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ii Anne G. Osborn, MD, FACR Kevin R. Moore, MD Distinguished Professor of Radiology William H. and Patricia W. Chil...

Author: Anne G. Osborn | Jeff Ross | Julia Crim | Karen L. Salzman | Susan I. Blaser

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ii

Anne G. Osborn, MD, FACR

Kevin R. Moore, MD

Distinguished Professor of Radiology William H. and Patricia W. Child Presidential Endowed Chair in Radiology University of Utah School of Medicine Salt Lake City, Utah

Pediatric Radiologist and euroradiologist Primary Children's Medical Center Department of Medical Imaging Salt Lake City, Utah

Jeffrey S. Ross, MD Neuroradiology Barrow eurologicallnstitute St. Joseph's Hospital Phoenix, Arizona

Lubdha M. Shah, MD Assistant Professor of Radiology University of Utah School of Medicine Salt Lake City, Utah

Miral D. Jhaveri, MD Karen L. Salzman, MD Associate Professor of Radiology Division of Neuroradiology University of Utah School of Medicine Salt Lake City, Utah

Assistant Professor Department of Diagnostic Radiology & Nuclear Medicine Rush University Medical Center Chicago, Illinois

Bronwyn E. Hamilton, MD Julia Crim, MD Chief of Musculoskeletal Radiology Professor of Radiology University of Utah School of Medicine Salt Lake City, Utah

Bryson Borg, MD Chief of Neuroradiology, MagnetIC Resonance Imaging Keesler Medical Center Keesler Air Force Base,Mississippi

Assistant Professor of Radiology Oregon Health & Science University Portland, Oregon

Susan I. Blaser, MD, FRCPC Staff euroradiologist The Hospital for Sick Children Associate Professor, Neuroradiology University of Toronto Ontario, Canada

Gregory L. Katzman, MD, MBA Professor and Chairman, Radiology University of Texas Medical Branch lohn Sealy Distinguished Endowed Chair of Radiology Galveston, Texas

AMIRSYS Names you know. Content you trust.

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AMIRSYS<& Names you know. Content you trust.-

First Edition Copyright © 2009 Amirsys, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or media or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from Amirsys, Inc. Composition

by Amirsys, Inc., Salt Lake City, Utah

Printed in Canada by Friesens, Altona, Manitoba,

Canada

ISBN: 978-1-9318-8402-0

Notice and Disclaimer The Information In this product ("Product") is provided as a reference for use by licensed medical professionals and no others. It does not and should not be construed as any form of medical diagnosis or professional medical advice on any matter. Receipt or use of this Product, In whole or in part, does not constitute or create a doctor-patient, therapist-patient, or other healthcare professional relationship between Amlrsys Inc. (" Amirsys") and any recipient. This Product may not reflect the most current medical developments, and Amirsys makes no claims, promises, or guarantees about accuracy, completeness, or adequacy of the information contained in or linked to the Product. The Product Is not a substitute for or replacement of professional medical judgment. Amirsys and its affiliates, authors, contributors, partners, and sponsors disclaim all liability or responsibility for any injury and/or damage to persons or property in respect to actions taken or not taken based on any and all Product information. In the cases where drugs or other chemicals are prescribed, readers are advised to che
Library of Congress Cataloging-in-Publication

repackaged or altered in any way by any third party.

Data

Expertddx. Brain and spine / [edited by] Anne G. Osborn, Jeffrey S. Ross, Karen L. Salzman. -- 1st ed. p.;cm. includes bibliographical references and index. ISBN 978-1-931884-02-0 1. Brain--Diseases--Diagnosis--Atlases. 2. Spine--Diseases--Diagnosis--Atlases.3. Diagnosis, Differential. I. Osborn, Anne G., 1943II. Ross, Jeffrey S. Oeffrey Stuart) III. Salzman, Karen L. IV. Title: Bra.in and spine. [DNLM: 1. Brain Diseases--diagnosis--Handbooks. 2. Diagnosis, Differential--Handbooks. 3. Diagnostic Imaging--Handbooks. 4. Spinal Diseases--diagnosis--Handbooks. WL 39 E96 2009] RC386.S.E97 2009 616.807S--dc22 200804133S

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To our (amilies and loved ones IVhose L1llSlinting support dllring the grlleling proce.5So( creating a bmlldneIV kind o( book IVas essential (evm crt/cia I) La ollr success. T/Janks and big /Jllgs!

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CONTRIBUTING AUTHORS Yoshimi Anzai, MD, MPH Professor, Department of Radiology University of Washington Medical Center Seattle, Washington

Nancy J. Fischbein, MD Associate Professor of Radiology and, by courtesy, Otolaryngology-Head and Neck Surgery Stanford University Medical Center Stanford, California

Gary M. Nesbit, MD Professor of Radiology, Neurology, Neurosurgery, and the Dotter Interventionallnstitute Oregon Health & Science University Portland, Oregon

Sheri Harder, MD Assistant Professor of Radiology Lorna Linda University Medical Center Lorna Linda, California

James D. Eastwood, MD Associate Professor of Radiology Duke University Medical Center Durham, North Carolina

H. Ric Harnsberger, MD Professor of Radiology R.C. Willey Chair in Neuroradiology University of Utah School of Medicine Salt Lake City, Utah

Troy Hutchins, MD Visiting Instructor University of Utah School of Medicine Salt Lake City, Utah

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EXPERf(D D BRAIN AND SPINE Once the appropriate technical protocols have been delineated, the best quality images obtained, and the cases queued up on PACS, the diagnostic responsibility reaches the radiology reading room. The radiologist must do more than simply "lay words on" but reach a real conclusion. If we cannot reach a definitive diagnosis, we must offer a reasonable differential diagnosis. A list that's too long is useless; a list that's too short may be misleading. To be useful, a differential must be more than a rote recitation from some dusty book or a mnemonic from a lecture way back when. Instead, we must take into account key imaging findings and relevant clinical information. With these considerations in mind, we at Amirsys designed our Expert Differential Diagnoses seriesEXPERTddx for short. Leading experts in every subspecialty of radiology identified the top differential diagnoses in their respective fields, encompassing specific anatomic locations, generic imaging findings, modality-specific findings, and clinically based indications. Our experts gathered multiple images, both typical and variant, for each EXPERTddx. Each features at least eight beautiful images that illustrate the possible diagnoses, accompanied by captions that highlight the pertinent imaging findings. Hundreds more are available in the eBook feature that accompanies every book. In classic Amirsys fashion, each EXPERTddx includes bulleted text that distills the available information to the essentials. You'll find helpful clues for diagnoses, ranked by prevalence as Common, Less Common, and Rare but Important. Our EXPERTddx series is designed to help radiologists reach reliable-indeed, expert-conclusions. Whether you are a practicing radiologist or a resident/fellow in training, we think the EXPERTddx series will quickly become your practical "go-to" reference.

Anne G. Osborn, MD Executive Vice President and Editor-in-Chief, Amirsys Inc. Paula J. Woodward, MD Executive Vice President and Medical Director, Amirsys Inc.

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PREFACE Expert Differential Diagnosis: Brain and Spine is comprised of over 250 expert differential diagnoses that cover a broad spectrum of central nervous system diseases focused on the brain and spine. As with all books in the EXPERTddx series, each topic is grouped according to anatomic location, generic imaging finding(s), modality-specific finding(s), or clinically based finding(s). A number of modules actually reflect more than one category. For example, "Suprasellar Masses, Pediatric" is both an anatomic location and a clinical (age-specific) finding while "Tllsointense Suprasellar Mass" is both a modality-specific and anatomically driven differential diagnosis.

Some EXPERTddxs have two or in a few cases even three modalilty-specific findings paired with an anatomic location (e.g., "Tl/T2 Isointense Parenchymal Lesions"). Obviously, the possible combinations of findings, locations, and clinical indications could generate a nearly infinite list of expert differential diagnoses. Too few EXPERTddxs are too superficial to be helpful. Too many becomes overwhelming. Our expert panel has created what we think is a very useful list of EXPERTddxs in the brain and spine (head and neck, the third "leg" of neuroradiology, will follow in 6 months). We know we have inevitably left some EXPERTddxs off the list. Equally inevitable, we also know we may have left an entity or two or three off an individual EXPERTddx that could have/should have been included. So we invite you, our readers, to send us your comments and suggestions. One of the great advantages of having an eBook companion included as part of your purchase is that updates, revisions, and additions will be added throughout the book's life. Have a suggestion or comment? Want to request a new EXPERTddx? Email me at aosborn@ amirsys.com and we will consider your suggestions. You just might find your idea showing up within a few weeks' time! Have a cool case or a better illustration? Send it along! Because we have created the whole new EXPERTddx series with you, our busy practicing colleagues in mind, we really do welcome your input! Finally, we have written Expert Differential Diagnosis: Brain and Spine so that it will be useful to both general radiologists as well as neuroradiologists and our colleagues in allied clinical specialties such as neurology and neurosurgery. We have included broad, overview ("general") EXPERTddxs as well as highly detailed, more in-depth modules that contain rare diagnoses only a subspecialist might need. Regardless of your level of specialization, we hope you will enjoy using our book and find it helpful in your daily practice. If it improves diagnostic accuracy and thus enhances patient care, we will have achieved our goal in publishing the Expert Differential Diagnosis series.

Anne G. Osborn, MD, FACR Distinguished Professor of Radiology William H. and Patricia W. Child Presidential Endowed Chair in Radiology University of Utah School of Medicine Salt Lake City, Utah

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ACKNOWLEDGMENTS Text Editing Douglas Grant Jackson Ashley R. Renlund, MA Kellie J. Heap

Image Editing Jeffrey J. Marmorstone Mitch D. Curinga

Medical Text Editing llenry J. Baskin, Jr., MD

Art Direction and Design Lane R. Bennion, MS Richard Coombs, MS

Production Lead Melissa A. Iloopes

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SECTIONS PART I

Skull and Brain Scalp, Skull Meninges Ventricles, Periventricular Regions Extra-Axial Spaces and Subarachnoid Cisterns Brain Parenchyma, General Supratentorial Brain Parenchyma Infratentorial Brain Parenchyma Sella/Juxtasellar, Pineal Region Arteries Veins, Venous Sinuses

PART II Spine Trans-Spatial Craniovertebral Junction Vertebral Body - Posterior Elements Intervertebral Disc - Endplate Extradural Intradural-Extramedullary Intramed u lIary

xv

SECTION 2

PART I

Meninges

Skull and Brain

Anatomically Based Differentials

SECTION 1

Dural Calcification(s)

1·2·2

Miral D. Jhaveri, MD

Scalp, Skull

Dural-based Mass, Solitary

1·2·4

Miral D. Jhaveri, MD

Anatomically Based Differentials Skull Normal Variants

Dural-based Masses, Multiple 1·1-2

Falx Lesions

Miral D. Jhaveri, MD

Scalp Mass

1·2·8

Miral D. [haveri, MD

1·1·4

1·2·12

Miral D. Jhaveri, MD

Miral D. Jhaveri, MD

Generic Imaging Patterns Generic Imaging Patterns "Hair on End"

Thick Dura/Arachnoid, Generalized 1·1·6

Pial Enhancement

Miral D. Jhaveri, MD

Thick Skull, Generalized

1·1·8

1·2·16

Yoshimi Anzai, MD, MPH & Judy Tan, MD

Dural Tail Sign

Miral D. Jhaveri, MD

Thick Skull, Localized

1·2·14

Yoshimi Anzai, MD, MPH & Judy Tan, MD

1·1·12

1·2·20

Miral D. /haveri, MD

Miral D. Jhaveri, MD

Thin Skull, Generalized Thin Skull, Localized

1-1-16

Miral D. /haveri, MD

Lytic Skull Lesion, Solitary

1·1·22

Miral D. Jhaveri, MD

Sclerotic Skull Lesion, Solitary Miral D./haveri, Miral D./haveri,

Anatomically Based Differentials Ventricles, Normal Variants

1·1·26

MD

Sclerotic Skull Lesions, Multiple

Ventricles, Periventricular Regions

1·1·18

Miral D. Jhaveri, MD

Multiple Lucent Skull Lesions

SECTION 3

1·1·14

Miral D. Jhaveri, MD

1·3·2

Susan I. Blaser, MD, FRCPC

Choroid Plexus Lesions 1·1·30

MD

Ependymal/Subependymal Bronwyn E. Hamilton,

Clinically Based Differentials

1·3·6

Karen L. Salzman, MD

Lesions

1·3-8

MD

Lateral Ventricle Mass

1-3·12

Karen L. Salzman, MD

Macrocephaly

1·1-32

Susan I. Blaser, MD, FRCPC

Microcephaly Susan I. Blaser, MD, FRCPC

Thick Septum Pellucidum

1-3·16

Karen L. Salzman, MD

1·1·38

Foramen of Monro Mass

1·3-18

Karen L. Salzman, MD

Third Ventricle Mass, General

1·3·22

Karen L. Salzman, MD

Third Ventricle Mass, Body/Posterior

1-3·26

Gregory L. Katzman, MD, MBA

Cerebral Aqueduct/Periaqueductal Karen L. Salzman, MD

XVI

Lesion

1·3·28

1-3-32

Fourth Ventricle Mass

Generic Imaging Patterns

Korell L. Salzillo II, MD

Enhancing

Generic Imaging Patterns "Bubbly-Appearing"

Intraventricular

/Jramvy" E. HOllliltall,

1-4-50

CSF-like Extra-Axial Fluid Collection 1-3-36

Mass

MD

Yasl1imi Alllai,

MO, MPH & Jllrly TOI7,MO

1-4-52

CSF-like Extra-Axial Mass 1-3-40

Ependymal Enhancement Bromvyn E. Hamilton, MD

Yasllimi Alllai,

MO, MPI-j & Jlldy TOI7,MO

Sulcal/Cisternal 1-3-44

Large Ventricles Bramvy" E. HOllliltall,

1-4-46

Cranial Nerve(s)

Alllle G. Osbam, MO, FACR

MO

1-4-54

Enhancement

Sl1eri L. /larrler, MO

1-4-58

Fat in Sulci/Cisterns/Ventricles

Small Ventricles

1-3-48

Yasllillli Allzai, MD, MPH & Jllrly Tall, MD

Bronwy" E. HamiltoIJ, MD

1-3-50

Asymmetric Lateral Ventricles /JroIlWYII E. Homiltall,

MO

Irregular Lateral Ventricles

1-3-54

Extra-Axial Flow Voids

1-3-58

T1 Hyperintense

Bromvyn E. Hamilton, MD

Periventricular

Enhancing

Lesions

Modality-Specific

Brollwy" E. Hamilton, MD

Intraventricular

Imaging Findings

Calcification(s)

1-3-62

Karen L. Salzman, MD

Periventricular

1-4-60

JOllies O. Eastwaad, MO

1-4-62

CSF

Branwy" E. Hamilton, MD

FLAIR Hyperintense

Modality-Specific

Imaging Findings

1-4-64

CSF

/JromvYII E. HOllliltal7, MD

T2 Hypointense

Extra-Axial Lesions

1-4-68

Bronwyn E. Hamilton, MD

1-4-72

Hyperdense CSF

Calcification

1-3-66

5115011 J. Blaser, MO, FRCPC

Periventricular

T2/FLAI R Hyperintense

Tray /llItellil7s,

MO & Korell L. Salzillo 11,MO

1-3-72

Lesions

Bronwyn E. Harniltofl, MD

Hyperdense Extra-Axial Mass(es) Miral o. JllOveri, MO

1-4-74

Hypodense

1-4-76

Extra-Axial Mass(es)

Brollwyn E. Hamilton, 1\1D

SECTION 4 Extra-Axial Spaces and Subarachnoid Cisterns

SECTION 5 Brain Parenchyma, General

Anatomically Based Differentials

Generic Imaging Patterns

Cistern, Subarachnoid

Space Normal Variants

1-4-2

Epidural Mass, Brain

1-4-4

Enlarged Sulci, Generalized

1-4-8

Effaced Sulci, Generalized

1-4-12

1-5-6

Lesion, Solitary

Effaced Sulci, Focal

1-4-16

Alllle G. Osbom, MO, FAC/I

Fissure Cysts

1-4-20

1-5-16

Mass, General

CSF-like Parenchymal

Lesion(s)

G. Osbam, MO, FACR & James

1-5-22

o. Eostwaorl,

Cyst with Nodule

MO

1-5-28

Troy lIutchins, MD & Karen L. Salzman, MD

1-4-24

Fat-like Lesion(s), General

1-5-32

Sireri L. Harrier, MO

H. /lie Homsberger, MO

Cystic CPA Mass

1-5-12

Lesion, Multiple

Solitary Cystic Parenchymal

Al7l7e

Alllle G. Osbam, MD, FACR

CPA Mass, Adult

Ring-Enhancing

AlIl7e G. Osbam, MO, FACR

Alllle G. Osbom, MD, FACR

1-4-28

Modality-Specific

H. Rie Homsberger, MD

Cistern Mass

1-4-32

Gregary L. Kotzmal7, MO, MBA

Cisterna Magna Mass Gregary L. Kotlmol7,

Ring-Enhancing

Yasl1imi Al7l0i, MO, MPH & Jllrly Tall, MO

Alllle G. Osba/"ll, MO, FACR

Prepontine

1-5-2

Lesions, General

Yasllillli Allzoi, MO, MPH & Jlldy Tall, MO

SI1CriL. Harrier, M 0

Interhemispheric

Multiple Enhancing Karen L. Salzman, MD

KorCll L. Salzillo 11,MD

Karen L. Salzman, MD

Calcification

1-5-34

Alllle G. Osbom, MO, FACR

1-4-38

MO, M/JA

Foramen Magnum Mass

Solitary Parenchymal

Imaging Findings

Multiple Parenchymal

Calcifications

1-5-40

Al7l1e G. Osbom, MO, FACR

1-4-42

Solitary J-1yperdense Parenchymal Al7l7e

Lesion

1-5-44

G. Osbam, MO, FACR

Multiple Hyperdense

Parenchymal

Lesions

1-5-50

Arme G. Osbom, MO, FACR

XVII

Solitary Hypodense

Parenchymal

Lesion

1-5-56

Anne G. Osborn, MD, FACR

Multiple Hypodense

Parenchymal

Multiple Brain Hyperintensities Common

Lesions

1-5-60

(T2/FLAlR),

1-5-64

Abnormal Shape/Configuration Callosum

1-6-46

of Corpus

Susan T. Blaser, MD, FRCPC

Corpus Callosum Holes

Gary M. Nesbit, MD

1-6-52

Karen L. Salzman, MD

Multiple Brain Hyperintensities Common

(T2/FLAlR), Less

1-5-70

Corpus Callosum Lesion without Mass Effect

1-6-54

Karen L. Salzman, MD

Gary M. Nesbit, MD

Corpus Callosum Mass

Multiple Brain Hyperintensities but Important

(T2/FLAIR), Rare

1-5-76

Karen L. Salzman,

Multiple Hypointense

Foci on T2

1-5-80

Nancy f. Fischbein, MD

1-6-58

MD

1-6-62

Basal Ganglia Calcification Karen L. Salzman, MD

Multiple Hypointense

Foci on GRE/SWI

1-5-82

Nancy f. Fischbein, MD

Tl/T2 Hyperintense

1-6-56

Karen L. Salzman, MD

Corpus Callosum Splenium Lesion

Gary M. Nesbit, MD

Tl Hyperintense Karen L. Salzman,

Parenchymal

Lesions

1-5-86

Anne G. Osborn, MD, FACR

T2 Hyperintense

Basal Ganglia MD

1-6-66

Basal Ganglia

1-6-70

Karen L. Salzman, MD

T2 Hyperintense

Parenchymal

1-5-90

1-6-74

Enlarged Perivascular Spaces Karen L. Salzman, MD

Anne G. Osborn, MD, FACR

TlfT2

1-6-40

Susan T. Blaser, MD, FRCPC

Karen L. Salzman, MD

Tl Hypointense, Lesions

Thin Corpus Callosum

Isointense

Parenchymal

Lesions

1-5-94

Anne G. Osborn, MD, FACR

Restricted Diffusion Bronwyn E. Hamilton,

Tl Hyperintense

1-5-98 MD

Parenchymal

Lesion(s)

1-5-102

Anne G. Osborn, MD, FACR

Perivascular Space Enhancing

Lesions

1-6-76

Karen L. Salzman, MD

1-6-80

Bilateral Basal Ganglia Lesions Nancy f. Fischbein, MD

Putamen Lesion(s)

1-6-84

Karen L. Salzman, MD

1-6-86

Globus Pallidus Lesion(s) Karen L. Salzman, MD

Clinically Based Differentials Brain Tumor in Newborn/Infant 1 Year

1-5-112

1-6-92

Nancy f. Fischbein, MD

1-6-96

"Pulvinar Sign"

Susan T. Blaser, MD, FRCPC

1-5-118

Epilepsy, General Bronwyn E. Hamilton,

Karen L. Salzman, MD

Bithalamic Lesions

Susan T. Blaser, MD, FRCPC

Brain Tumor in Child>

1-6-90

Unilateral Thalamic Lesion 1-5-106

Karen L. Salzman, MD

Tectal (Quadrigeminal

MD

1-6-98

Plate) Lesion

Karen L. Salzman, MD

SECTION 6 Supratentorial Brain Parenchyma

1-6-2

Gregory L. Katzman, MD, MBA

Thick Cortex

1-6-8 1-6-14 1-6-20

Karen L. Salzman,

T2/FLAIR

1-6-24

Cortical Enhancement

1-6-28

Solitary White Matter Lesion

1-6-30

Confluent

White Matter Lesions

Gary M. Nesbit, MD

Midline Cyst

1-6-34

1-7-18

Gregory L. Katzman, MD, MBA

Cerebellar Mass Gregory L. Katzman, MD, MBA

XVlll

1-7-14

Gregory L. Katzman, MD, MBA

Cerebellar Atrophy

Gary M. Nesbit, MD

1-7-10

Nancy f. Fischbein, MD

Infratentorial

Karen L. Salzman, MD

1-7-6

Nancy f. Fischbein, MD

Medulla Lesion

MD

1-7-4

Karen L. Salzman, MD

Pontine Lesion

fames D. Eastwood, MD

1-7-2

Karen L. Salzman, MD

Small Brainstem

Susan T. Blaser, MD, FRCPC

Focal Cortical Mass Cortical Hyperintensity

Anatomically Based Differentials Large Brainstem

Susan T. Blaser, MD, FRCPC

Thin Cortex

1-6-100

Nancy f. Fischbein, MD

SECTION 7 Infratentorial Brain Parenchyma

Anatomically Based Differentials Asymmetric Cerebral Hemispheres

Midbrain Lesion

1-7-22

Vermis Mass Gregory L. Katzmall,

Low

1-7-28

Modality-Specific

1-7-32

Hyperdense Suprasellar Mass

MD, MBA

erebellar Tonsils

Gregory L. Katzmall,

MD, MBA

Imaging Findings 1-8-52

AlIl1e G. Osbom, MD, FACR

Tl Isointense Suprasellar Mass

Generic Imaging Patterns "Cystic-Appearing"

Posterior Fossa Lesion

1-8-54

Alllle G. Osborn, MD, FACR

1'1 Hyperintense 1-7-34

SlIsall I. Blaser, MD, FRCPC

Suprasellar Mass

1-8-56

Alllle G. Osborn, MD, FACR

T1 Hypointense

Suprasellar Lesion

1-8-58

AlIl1e G. Osborn, MD, FAC/I

Clinically Based Differentials Posterior Fossa

eoplasm, Adult

1-7-40

SECTION 9

1-7-44

Arteries

Al1l1e G. Osborn, MD, FACR

Posterior Fossa Neoplasm, Pediatric SlIsal1l. Blaser, MD, FRCPC

Anatomically Based Differentials

SECTION 8

Abnormalities

Sella/Juxtasellar, Pineal Region

of Arterial Shape/Configuration

1-9-2

Am.e G. Osborn, MD, FACR

1-9-6

Fusiform Arterial Enlargement Siler; L. Harder, MD

Anatomically Based Differentials Pineal Region Mass, General

1-8-2

Gregory L. Katzmal1, MD, MBA

Ilyperattenuating

Pineal Gland Mass

1-8-6

Karel1 L. Salzman, MD

Quadrigeminal

Slier; L. Harder, M

("Dense") Artery

1-9-8

1-8-8

1-9-10

Gregory L. Katzlllal1, MD, MBA

MD, MBA

Pineal + Suprasellar Lesions

1-8-10

SECTION 10

Karen L. Salzmall, MD

Sella/Pituitary

°

Imaging Findings

Vascular Calcification(s)

istern Mass

Gregory L. Katzmall,

Modality-Specific

Normal Variants

Veins, Venous Sinuses

1-8-12

Al1l1e G. Osborn, MD, FACR

SeliarIJuxtaseliar

Calcification

1-8-14

Al1l1e G. Osborn, MD, FACR

1-8-18

Enlarged Pituitary Gland

1-8-20

lntrasellar Lesion

1-10-2

E. Hamillol1, MD & AlIl1e G. Osbom, MD, FAC/I

Enlarged Cortical Veins

1-10-8

jmlles D. Eastwood, MD

Alllle G. Osborn, MD, FACR

1-8-22

Cystic Intrasellar Mass Alllle G. Osborn, MD, FACR

Enlarged Deep (Medullary/Ependymal)

Veins

1-10-10

james D. Eastwood, MD

1-8-24

Suprasellar Mass, General

Unilateral Cavernous Sinus Mass

1-10-14

Alllle G. Osbom, MD, FACR

Amle G. Osborn, MD, FACR

Suprasellar Masses, Pediatric

1-8-30

Bilateral Cavernous Sinus Lesions

1-10-18

A.me G. Osbom, MD, FACR

SlIsall I. Blaser, MD, FlICPC

1-8-36

Suprasellar Cystic Mass

Meckel Cave Lesion

1-10-22

A.lIle G. Osbom, MD, FACR

Al1l1e G. Osborn, MD, FACR

1-8-40

Calcified Suprasellar Mass

Modality-Specific

Al1l1e G. Osborn, MD, FACR

Enhancing Suprasellar Mass

1-8-42

A.lIle G. Osbom, MD, FACR

Infundibular

Dural Sinus Lesion, General Bro"wy"

Al1l1e G. Osbom, MD, FACR

Absent/Thin

Anatomically Based Differentials

Hyperdense Dural Sinus

Imaging Findings 1-10-26

Al1l1e G. Osborn, MD, FACR

Stalk

1-8-44

Al1l1e G. Osborn, MD, FACR

Thick Infundibular

Stalk

1-8-46

A.me G. Osborn, MD, FACR

Hypothalamus

Lesion

1-8-48

Al1l1e G. Osborn, MD, FACR

XIX

SECTION 2 Craniovertebral Junction

PART II Spine

Anatomically Based Differentials

SECTION 1 Trans-Spatial

Cranio-Cervical junction Acute Injury

11-2-2

Julia Grim, MD

CVj Abnormality, General

11-2-4

Julia Grim, MD

Anatomically Based Differentials Cervical, Chronic Post-Traumatic Abnormality

CVj Soft Tissue Abnormality 11-1-2

11-2-8

Jeffrey S. Ross, MD

Julia Grim, MD

Cervical, Lower, Post-Traumatic Bony Abnormality

11-1-4

Generic Imaging Patterns CI-C2 Instability

Julia Grim, MD

11-2-12

Julia Grim, MD

Thoracic Bony Trauma

11-1-6

Julia Grim, MD

Odontoid Deformity

11-2-14

Julia Grim, MD

Lumbar Bony Trauma

11-1-8

Julia Grim, MD

Generic Imaging Patterns Scoliosis

11-1-10

Julia Grim, MD

11-1-12

Kyphosis Julia Grim, MD

11-1-14

Kyphoscoliosis, Child Julia Grim, MD

11-1-16

Julia Grim, MD

Kevin R. Moore, MD

11-1-26

Sacral Deformity Bryson Borg, MD

11-3-4

Flattened Vertebral Body, Solitary

11-3-6

Julia Grim, MD

Flattened Vertebral Body, Multiple

11-3-8

Julia Grim, MD

Dysmorphic Vertebral Body

Clinically Based Differentials Post-Operative

Chronic Back PainJRadiculopathy, Post-Operative

11-1-30

Enlarged Vertebral Body/Posterior Element

11-3-12

Lubdha M. Shah, MD

11-1-36

Enlarged Neural Foramen

11-3-16

Bryson Borg, M0

Kevin R. Moore, MD

Acute Upper Extremity PainJWeakness

11-3-10

Julia Grim,MD

Kevin R. Moore, MD

Vertebral Body ScallopingJWidened 11-1-42

Kevin R. Moore, MD

Bryson Borg, MD

11-3-20 11-3-24

Lubdha M. Shah, MD

Fracture, Vertebral Body 11-1-56

11-3-18

Jeffrey S. Ross, MD

Bony Lesion, Aggressive 11-1-52

Canal

Bryson Borg, MD

Spondylolisthesis 11-1-48

Bryson Borg, MD

Kevin R. Moore, MD

Cervical Bony Fusion

Generic Imaging Patterns 11-1-22

Sacrococcygeal Mass, Pediatric

Back Pain, Pediatric

11-3-2

11-1-18

Lubdha M. Shah, MD

Back Pain, Adult

Congenital Vertebral Anomalies

Julia Grim, MD

Sacral Mass, Adult

Lower Extremity Pain

Anatomically Based Differentials Julia Grim, MD

Platyspondyly, Diffuse

Acute Back Pain/Radiculopathy,

SECTION 3 Vertebral Body - Posterior Elements

11-3-28

Julia Grim, MD

Facet Abnormality, Non-traumatic

11-3-32

Lubdha M. Shah, MD

Fracture, Posterior Element

11-3-34

Julia Grim, MD

Pedicle Abnormality Bryson Borg, MD

xx

11-3-36

Modality-Specific

Imaging Findings

Enlarged Vertebral Body, Soap Bubble Expansion

11-3-42

Modality-Specific Soft Tissue Calcification,

Bryso/l Borg, MD

Vertebral Body Sclerosis, Diffuse

11-3-44

Bryso/l Borg, MD

Vertebral Body Thickened

Bony Trabeculae

11-3-46

Imaging Findings

Paraspinal

11-5-20

Extradural, Normal Marrow Signal

11-5-22

/11/;0 Cr;m, MD Kev;/I R. Moore, MD

Extradural, Abnormal Marrow Signal

Lllbd/IO M. Shah, MD

Vertebral Body, Tl Hyperintense

Signal, Diffuse

11-3-48

Vertebral Body, TJ Hyperintense

Signal, Focal

11-3-50

Vertebral Body, Tl Hypointense

Signal, Diffuse

11-3-52

Kevin R. Moore, MD

Vertebral Body, Tl Hypointense

Signal, Focal

11-3-56

Bryso/l Borg, MD

SECTION 4 Intervertebral Disc - Endplate

T1

11-5-36

Tl

11-5-40

Extradural Lesion, T2 Hyperintense, Isointense Bryson Borg, M 0

Bryson Borg, MD

Clinically Based Differentials Lumbar Soft Tissue Mass, Pediatric

Generic Imaging Patterns

11-5-42

Kev;" R. Moore, MD

11-4-2

Disc Contour Abnormality Jeffrey S. //055, M 0

Disc/Endplate

11-5-32

Bryso/l Borg, MD

Extradural Lesion, T2 Hypointense, I-Iypointense

Irregularity

11-4-6

Vertebral Endplate Contour Abnormality

11-4-10

Jeffrey S. Ross, MD /Illia Crilll, MD

SECTION 6 Intrad ural- Extramed uIlary Anatomically Based Differentials

Modality-Specific

Imaging Findings

Disc, Tl Hypointense

11-4-12

Jeffrey S. Ross, M 0

Intervertebral

11-5-30

Bryson Borg, M 0

Extradural Lesion, T1 Hypointense

Kevin R. Moore, MD

Intervertebral

11-5-26

Kev;n R. Moore, MD

Extradural Lesion, T1 Hyperintense

Kevin R. Moore, MD

Intervertebral

11-5-16

Kevin R. Moore, MD

11-3-38

Lllbd/IO M. SIlO/I, MD

Vertebral Body Sclerosis, Focal

Extradural Lesion, Solid Enhancement

Cauda Equina Enhancement,

Diffuse

11-6-2

Jeffrey S. Ross, MD

Subarachnoid

Space Narrowing

11-6-6

Blyso/l Borg, MD

Disc, T2 Hyperintense

11-4-14

Jeffrey S. Ross, M 0

Vertebral Endplate Signal Abnormality

11-4-16

Intradural/Extramedullary, Enhancement

Leptomeningeal

11-6-8

Kevin R. Moore, MD

Jeffrey S. Ross, M 0

Generic Imaging Patterns

SECTION 5 Extradural

Intradural/Extramedullary Enhancement

Lesion, No

11-6-12

Lesion, Solid

11-6-14

Kev;n R. Moore, MD

Intradural/Extramedullary Enhancement

Anatomically Based Differentials Epidural Mass, Spine

11-5-2

Ventral/Lateral

Kevin R. Moore, MD

Intradural Lesion, Serpentine

Bryso/l Borg, MD

Paraspinal Mass

11-5-8

Intradural/Extramedullary

Jeffrey S. Ross, M 0

11-6-18

Jeffrey S. Ross, MD

Lesion, Multiple

11-6-20

Bryson Borg, M 0

Generic Imaging Patterns Paraspinal Muscle Abnormality

11-5-10

Jeffrey S. Ross, MD

Extradural Lesions, Multiple

11-5-12

Bryso/l Borg, MD

Extradural Lesion, No Enhancement /11/;0 Cr;m, MD

11-5-14

Modality-Specific

Imaging Findings

Intradural/Extramedullary Lesion, Ring/Peripheral Enhancement

11-6-22

Kev;n R. Moore, MD

Intradural/Extramedullary Hyperi n tense

Lesion, T1

11-6-26

Jeffrey S. Ross, MD

XXI

Intradural/Extramedullary Hypointense

Lesion, T1

11-6-28

Myelopathy

/effrey S. Ross, MD

Intradural/Extramedullary Hypo

Lesion, Tl Hypo, T2

11-6-32

Lesion, T2 Hyper, Tl

11-6-34

/effrey S. Ross, MD

Intradural/Extramedullary Iso /effrey S. Ross, M D

Clinically Based Differentials Cauda Equina Syndrome

11-6-36

Bryson Borg, MD

SECTION 7

Intramedullary Anatomically Based Differentials Intramedullary

Mass

11-7-2

Bryson Borg, MD

Conus Abnormality

11-7-6

Bryson Borg, MD

Generic Imaging Patterns 11-7-10

Cord, Small/Atrophic Bryson Borg, MD

Intramedullary

Lesions, Multiple

11-7-12

Lubdha M. Shah, MD

Intramedullary

Lesion, Solid Enhancement

11-7-14

Lubdha M. Shah, MD

Intramedullary

Lesion, No Enhancement

11-7-18

Lubdha M. Shah, MD

Intramedullary Enhancement

Lesion, Diffuse/Ill-defined

11-7-20

Jeffrey S. Ross, MD

Intramedullary Enhancement

Lesion, Ring/Peripheral

11-7-24

Lubdha M. Shah, MD

Modality-Specific Intramedullary Hypointense

Imaging Findings

Lesion, Tl Hypointense, T2

11-7-26

Lubdha M. Shah, MD

Intramedullary

Lesion, T1 Hypointense

11-7-28

Lubdha M. Shah, MD

Intramedullary Isointense

Lesion, T2 Hyperintense, Tl

11-7-30

LlIbdha M. Shah, MD

Intramedullary

Lesion, T1 Hyperintense

11-7-34

Lubdha M. Shah, MD

Cord Lesion, T2 Hyperintense, Ventral

11-7-38

Lubdha M. Shah, MD

Cord Lesion, T2 Hyperintense,

Dorsal

11-7-40

Central

11-7-44

Lubdha M. Shah, MD

Cord Lesion, T2 Hyperintense, Lubdha M. Shah, MD

XXII

Clinically Based Differentials Kevin R. Moore, MD

11-7-48

xxv

PART I Skull and Brain Scalp, Skull Meninges Ventricles, Periventricular Regions Extra-Axial Spaces and Subarachnoid Cisterns Brain Parenchyma, General Supratentorial Brain Parenchyma Infratentorial Brain Parenchyma Sella/Juxtasellar, Pineal Region Arteries Veins, Venous Sinuses

SECTION 1

Scalp, Skull Anatomically Based Differentials Skull Normal Variants Scalp Mass

1-1-2 1-1-4

Generic Imaging Patterns "Hair on End" Thick Skull, Generalized Thick Skull, Localized Thin Skull, Generalized Thin Skull, Localized Lytic Skull Lesion, Solitary Multiple Lucent Skull Lesions Sclerotic Skull Lesion, Solitary Sclerotic Skull Lesions, Multiple

1-1-6 1-1-8 1-1-12 1-1-14 1-1-16 1-1-18 1-1-22 1-1-26 1-1-30

Clinically Based Differentials Macrocephaly Microcephaly

1-1-32 1-1-38

SKULLNORMAL VARIANTS 0..

co o

DIFFERENTIAL DIAGNOSIS

(f) C

•.. I'll

co

'tl

c I'll

Common • Skull Normal Variants o Arachnoid Granulations, Calvarium o Vascular Grooves o Venous Lakes o Emissary Veins o Parietal Thinning o Asymmetric Marrow, Petrous Apex o Asymmetric Foramina Ougular, Oval e) o Aerated Clinoids o Accessory Sutures (e.g., Mendosal) • Hyperostosis Frontalis Interna Less Common • Prominent Convolutional

Markings

Rare but Important • Wormian Bones

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Important to recognize normal anatomic variations o These are "leave me alone" lesions o Should not be mistaken for real disease (e.g., metastases) Helpful Clues for Common Diagnoses • Skull Normal Variants o Arachnoid Granulations, Calvarium • Sharply demarcated defect in inner table • Adjacent to/within dural venous sinuses • CSF density/intensity

Arachnoid

I 1 2

Granulations,

Vascular Grooves • Usually inner table • Caused by meningeal arteries, veins • Outer table produced by superficial temporal artery branches o Venous Lakes • Round or oval configuration • Diploic venous channel can usually be traced into venous lakes o Emissary Veins • Connect meningeal veins/dural venous sinuses with pericranial (scalp) veins • Chiefly in frontal, parietal bones o Parietal Thinning • Elongated oval-shaped thinness • Upper part of parietal bone involved o Asymmetric Marrow, Petrous Apex • Non-pneumatized marrow hyperintense on TlWI • Opposite side pneumatized • Hyperostosis Frontalis Interna o Predominately inner table overgrowth o Usually bilateral, symmetrical o Frontal; usually stops at coronal suture o ± Orbital roofs, parietal bones o

Helpful Clues for Less Common Diagnoses • Prominent Convolutional Markings o Brain pulsations - inner table depressions o Children> > adults Helpful Clues for Rare Diagnoses • Wormian Bones o Lamboid suture> fontanelles o Variable size, number (2-3 normal)

Calvarium

Axial NEeT shows a sharply marginated osseous defect due to an arachnoid granulation invaginatjng through the inner table of the right occipital bone 81.

Emissary Veins

Axial bone CT shows linear defects in the calvarium caused by prominent emissary veins 81. Also note a prominent

venous lake ~.

SKULL NORMAL

Parietal Thinning

Asymmetric

en

VARIANTS

Marrow,

r:: "

Petrous Apex (Left) Axial bone CT shows classic bilateral parietal thinning 8t a normal variation. (Right) Axial bone CT shows a typical example of asymmetric aeration of the pelrous apex. There;s normal

{ally marrow

=

within

the left petrous apex with an aerated right pelrous apex 81.

Aerated C1inoids (Left) Axial bone CT shows asymmetric

jugular

foramina,

with the left 81 larger than the right =:l. More commonly the right is larger than the left. (Right) Coronal bone CT shows bilateral aerated clinoids 81.

Hyperostosis

Frontalis Interna

Wormian

Bones (Left) Axial bone CT shows hypertrophic bone {ormation along the inner table of frontal bones 8t consistent with benign hyperostosis frontalis interna. (Right) Bone CT shows a diamond-shaped wormian bone in the region of the anterior

fontanelle

~.

I 1 3

SCALP MASS a.

ro

u

DIFFERENTIAL DIAGNOSIS

(f)

.. c:

C'Cl

CD "'C

c: ro

Common • Subgaleal Hematoma • Foreign Body • Lipoma • Sebaceous Cyst • Metastases, Skull less Common • Dermoid Cyst • Epidermal Inclusion Cyst • Basal Cell Carcinoma • Squamous Cell Carcinoma • Edema/Anasarca • Hemangioma • Venolymphatic Malformations • Neurofibromatosis Type 1 • Lymphoma • Langerhans Cell Histiocytosis Rare but Important • Sinus Pericranii • Atretic Cephalocele • Sarcoma (Kaposi, etc.)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Density of mass on NECT helpful o Hyperdense: Acute subgaleal hematoma o Fat density: Lipoma, dermoid cyst o Fluid density: Sebaceous cyst, epidermal inclusion cyst

Subgaleal

Hematoma

• Enhancing mass + skull changes: Metastasis, squamous/basal cell carcinoma Helpful Clues for Common Diagnoses • Subgaleal Hematoma o Not confined by cranial sutures o Traumatic, post-surgical • Lipoma o Well-defined fat density/signal intensity • Sebaceous Cyst o Often fluid density/intensity • Metastases, Skull o Destructive skull lesion with associated scalp mass Helpful Clues for less Common Diagnoses • Dermoid Cyst o Midline, frontotemporal> parietal o Fat density, signal • Epidermal Inclusion Cyst o Location similar to dermoid cyst o Fluid density, signal • Venolymphatic Malformations o Multiseptate cystic masses ± intracystic hemorrhage/fluid levels o ± Phleboliths (signal voids) • Neurofibromatosis Type 1 o Plexiform neurofibroma unencapsulated, infiltrating • Langerhans Cell Histiocytosis o "Punched-out" skull lesion without reactive sclerosis o ± Enhancing soft tissue mass

Lipoma

I 1 4

Axial NECT shows a posl-lraumauc acute hyperdense subgaleal hematoma not confined by sutures ~ as well as an epidural hematoma

=.

Axial NECT shows a homogeneous fat density lipoma (;8 in the frontal scalp.

,.-

SCALP MASS

(Jl

c: Cl

::l

Co

..,

OJ

Sebaceous Cyst

Metastases, Skull

Cl

(Left) Axial NECT shows a well-defined fluid density sebaceous cyst [;g in the subcutaneous fat of the occipital scalp. (Right) Axial T1 C+ MR shows a destructive metastasis &:I centered in diploic space that destroys both inner & oUler tables and extends both medially into epidural space & laterally into subgaleal space.

Dermoid

Cyst

::l (Jl ()

0> "0 (Jl

""c:

Basal Cell Carcinoma (Left) Axial NECT shows a

=

well-circumscribed,

oval

lesion within the subcutaneous tissues near the right orbit with density similar to that of the

subcutaneous rat, typical or a dermoid cyst. (Right) Coronal CECT shows an enhancing soft tissue mass ~

with superficial

ulceration

P.:;. On

excisional biopsy, this proved to be a basal cell

Neurofibromatosis

Type 1

carcinoma.

The underlying

calvarium

was not involved.

Langerhans Cell Histiocytosis (Left) Axial T2WI FS MR in patient with neurofibromatosis type 7 and a scalp mass shows the infiltrating "whorlsl! of tumor that are typical of

=

plexiform

neurofibroma.

(RighI) Axial CECT shows a lytic skulliesioll ~ in a child with an associated large enhancing scalp mass typical of Langerhans cell

a

histiocytosis.

I 1 5

"HAIR ON END"

OJ

-'"

(f)

0-

ro ()

DIFFERENTIAL DIAGNOSIS

c: nl

•... llJ "0

c: nl

• Expanded diploic space Thalassemia • Most severe in thalassemia major o Sickle Cell Disease • 5% of radiographs show "hair on end" • Hemangioma, Skull o Sharply marginated expansile skull lesion o Spiculated "hair on end" (sunburst) or "honeycomb" pattern • Metastases, Skull o Localized or diffuse o Dural/scalp involvement common o Often known primary malignancy o

(f)

Common • Anemias o Thalassemia o Sickle Cell Disease o Hereditary Spherocytosis • Hemangioma, Skull • Metastases, Skull Less Common • Neuroblastoma, Metastatic • Iron Deficiency Anemia • Cyanotic Congenital Heart Disease Rare but Important • Leukemia • Osteopetrosis • Granulocyte Colony-Stimulating (G-CSF) Treatment

Factor

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • "Hair" o Expanded diploe + spiculated periostitis o Accentuated trabeculae between inner/outer tables • "On end" o Trabeculae oriented perpendicular to inner, outer tables Helpful Clues for Common Diagnoses • Anemias o General etiology • Red marrow hyperplasia

Helpful Clues for Less Common Diagnoses • Neuroblastomar Metastatic o Skull/orbit ± sutural widening • Iron Deficiency Anemia o Severe, chronic o Mostly nutritionally deprived children • Cyanotic Congenital Heart Disease o Marrow expansion in uncorrected complex CHD can mimic thalassemia Helpful Clues for Rare Diagnoses • Leukemia o Almost always with sub- or epidural tumor • Osteopetrosis o Expanded marrow space ~ spiculated periosteal reaction o Pattern similar to severe anemias • Granulocyte Colony-Stimulating Factor (G-CSF) Treatment o Long-term treatment in severe congenital neutropenia

Thalassemia

Thalassemia

I 1 6

Lateral radiograph shows typical appearance of thalassemia with dense striations in a widened diploic space, giving the "hair on end" appearanceEB

Axial bone CT shows lypical "hair on endM appearance of the skull secondary to marked thickening of the diploic

marrow

most common

space

EB

Thalassemia

major

cause of this imaging finding.

is the

"HAIR ON END"

(J)

" c: III

::::l

Co

..•

OJ

Sickle Cell Disease

Sickle Cell Disease

III

(Left) Lateral scout radiograph from CT shows marked diploic thickening

=

with "hair on end"

appearance

in

a

patient

with

sickle cell disease. (Right) 5agiltal T1 WI MR shows marked diploic thickening ~ with "hair on end" appearance in severe sickle cell anemia.

::::l (j) Cl

OJ "0

(j) A

c:

=

Hemangioma,

Skull

Neuroblastoma,

Metastatic (Left) Anteroposterior radiograph demonstrates a well-demarcated lesion within the left frontal bone &J with spiculated or honeycomb appearance from intra diploic trabecular thickening. (Right) Coronal T1 C+ MR shows classic "hair on end" pa£lern, typical for metastalic neuroblastoma =:I.

Neuroblastoma,

Metastatic

leukemia (Left) Anteroposterior radiograph shows periosteal new bone projecting

from

both inner &J and outer =:I table of the skull with bidirectional spiculation in metastatic neuroblastoma. (Right) Axial CCCT shows a spiculated appearance of the outer and inner calvarium

~

due to extensive

involvement

in

marrow

leukemia.

Note large enhancing masses along the dura =:I and in the scalp~".

I 1 7

THICK SKULL, GENERALIZED

-'(fJ'" 0-

ro

u

• Phenytoin (Dilantin) Use, Chronic o Look for combination of thick skull + cerebellar atrophy = probable chronic Dilantin therapy o Up to 34% among patients with seizure disorder + anticonvulsant therapy • Shunted Hydrocephalus o Chronic shunted hydrocephalus often associated with diffuse calvarial thickening o Look for thick skull + shunt + chronic collapsed ventricles • Metastases (Diffuse Sclerotic) o Fat-suppressed Tl C+ scans helpful in detecting calvarial, subtle dural metastases o Common with prostate & breast metastasis o Look for associated focal/diffuse dura-arachnoid involvement • Paget Disease o Initial osteolytic change of skull in osteoporosis circumscripta o Late osteosclerotic phase • Osteoblastic areas crossing sutures • Marked thickening of the diploic space • "Tam-o'-shanter" skull • Focal areas of sclerosis in expanded diploic space: "Cotton wool" appearance (of skull) o Platybasia with basilar invagination

DIFFERENTIAL DIAGNOSIS

(fJ

c: co

"-

III "0

c: co

Common • Skull Normal Variants o Diffusely Thick Skull, ormal o Hyperostosis Frontalis Interna • Phenytoin (Dilantin) Use, Chronic • Shunted Hydrocephalus • Metastases (Diffuse Sclerotic) • Paget Disease Less Common • Microcephaly • Fibrous Dysplasia • Hyperparathyroidism • Acromegaly • Subdural Hematoma, Chronic (Calcified) • Anemias o Iron Deficiency Anemia o Sickle Cell Disease o Thalassemia • Extramedullary Hematopoiesis Rare but Important • Sclerosing Bone Dysplasias o Osteopetrosis o Pycnodysostosis o Melorheostosis • Fluorosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Diffuse diploic space expansion with/without adjacent cortical thickening • Most common cause by far of "thick skull" normal variant!

I 1 8

=

Helpful Clues for Common Diagnoses • Skull Normal Variants o Most common cause o Females normally have significantly thicker parietal/occipital bones than males o Hyperostosis frontalis interna • Usually bilateral, symmetrical • Spares areas occupied by superior sagittal sinus, cortical venous channels • Often ends at coronal sutures • May extend to parietal bones, orbital roofs • Females> 3S years old • 0 clinical significance • Etiology unknown

Helpful Clues for Less Common Diagnoses • Microcephaly o Skull overgrowth occurs secondary to small brain o Small brain causes = developmental anomalies or a result of very early insult • Fibrous Dysplasia o Can involve any aspect of skull o Can be focal or extensive o Medullary expansion with ground-glass appearance is classic o Four disease patterns • Monostotic (70-80%) • Polyostotic (20-30%) • Craniofacial (can be isolated; up to 50% of polyostotic) • Cherubism (mandible, maxilla) • Hyperparathyroidism o Granular appearance of skull with multiple areas of normal bone interspaced between • "Salt & pepper" or "pepper pot skull" appearance o Loss of distinction of inner & outer table

,.-c:

THICK SKUll, GENERALIZED Loss of lamina dura o Brown tumors o Chronic renal disease: Secondary hyperparathyroidism o t Serum calcium, t parathyroid hormone, ~ serum phosphorus Acromegaly o Calvarial hyperostosis (esp. inner table) o Prognathism (elongation of mandible) o Sellar enlargement, erosion o Enlarged paranasal sinuses (mainly frontal): 75% o t Growth hormone & IGF-l Subdural Hematoma, Chronic (Calcified) o Chronic calcified subdural hematoma along inner table simulates thick skull o Look for subtle cleavage between calcified membranes and the inner table Anemias o Chronic anemias: Hemolytic or iron deficiency o "Hair on end" skull with beta thalassemia o Thick skull due to diploic space enlargement o Parietal bones most commonly affected, relative sparing of the occipital squamae Extramedullary Hematopoiesis o ECT: Smooth homogeneous hyperdense masses mimicking subdural hematoma o Osseous findings of underlying disease • Thalassemia: "Hair on end" skull • Osteopetrosis: Dense bone obliterating medullary space o

•

•

•

•

Diffusely Thick Skull, Normal

CJl

Helpful Clues for Rare Diagnoses • Sclerosing Bone Dysplasias o Osteopetrosis • Marked sclerosis and deposition of osteopetrotic bone • Neurologic deficits: Blindness, conductive hearing loss, facial nerve palsy due to foraminal encroachment o Skeletal series diagnostic for diffusely dense bones • Fluorosis o Skull shows minimal changes in fluorosis o Bones at the base show marked thickening o Occipital protuberance very prominent, falx calcification o Skeletal survey helpful Other Essential Information • Appearance of thick skull caused by o Thick cortex (e.g., hyperostosis frontalis) o Expanded diploic space (e.g., metastases, anemia) o Adjacent tissue (e.g., old calcified subdural hematoma)

SELECTED REFERENCES 1. 2. 3. 4.

Chow KM et al: Cerebral alrophy and skull thickening due to chronic phenytoin lherapy. CMAJ. 176(3):321·3.2007 She R et al: Hyperostosis frontalis interna: case report and review of literature. Ann Clin Lab Sci. 34(2):206-8, 2004 Hollar MA: The hair-on-end sign. Radiology. 221(2):347-8, 2001 Ita K et al: Accentualed temporal line on the frontal skull radiograph: a sign of hyperparathyroidism. Radiology. 192(2):497-S02, 1994

Hyperostosis

Frontalis Interna

I Axial bone CT demonSlrales a diffusely lhick skull. which is commonly seen as a normal variation.

=.

Axial bone CT shows diffuse skulllhickening with classic changes of benign hyperoslosis inlerna predominantly bifronlal in this pauent.

1 9

THICK SKUll,

GENERALIZED

Shunted Hydrocephalus (Left) Sagillal TI WI MR demonslrales dirruse skull lhickening ~ secondary 10 chronic

Oilanlin

therapy.

NOlice also cerebellar alrophy (Right) Laleral radiograph shows diffuse skulllhickening in a patient wilh chronically shunted hydrocephalus. The shunt lube ~ is also seen.

Metastases (Diffuse Sclerotic) (Leh) Axial bone CT shows a diffuse thick skull wilh focal sclerotic

regions

in

a

patient with prostate melaSlasis. (Right) Axial T I WI MR shows lhe lypical MR appearance of diffuse, extensive skull Paget disease wilh diffuse calvarial diploic thickening and heterogeneous marrow ~.

(Left) Axial bone CT in an extremely retarded 5 , year old shows diffuse skull thickening

secondary

to

small brain. (Right) Axial bone CT shows a Ihick skull due 10POlyoslOtiC (ibrous dysplasia. NOle lhe characteristic ground·glass appearance or the diploic space l:ll.

I 1 10

Paget Disease

en

THICK SKULL, GENERALIZED

~ c:

III

:J

C-

..,

O:! Hyperparathyroidism

Subdural Hematoma,

III

Chronic (Calcified) (Left) Axial bone CT shows thick skull with mild sclerosis and a granular appearance of the diploe, as well as loss of distinction of inner & Duler table, in a patient with chronic renal failure and secondary hyperparathyroidism. (Right) Axial T2WI MR demonstrates chronic, calcified, bifrontal subdural hematomas EE resulting in skull thickening.

Sickle Cell Disease

:J Ul () Q)

-0

Ul

'"c:

Thalassemia fLeft) Coronal T2WI MR shows diffuse bone thickening with marked diploic widening E±l of both calvarium & skull base. (Right) Coronal bone CT shows diffuse diploic thickening

=

with

"hair on

end" appearance caused by blood-forming bone marrow hyperplasia. The underlying brain is normal.

Osteopetrosis (Left) Coronal T1 WI MR shows diffuse skull thickening and a dural-based mass in extramedullary hematopoiesis. (Right) Axial bone CT shows dirruse sclerosis and thickening involving the skull base and facial bones in a patient with

=

osteopetrosis.

I 1 11

THICK SKULL, LOCALIZED n. ('(l ()

DIFFERENTIAL DIAGNOSIS

(j)

c: III

•...

a:l 1J

c: III

=

Common • Hyperostosis Frontalis lnterna • Meningioma • Metastasis (Osteoblastic) Less Common • Fibrous Dysplasia • Paget Disease • Dyke-Davidoff-Masson • Cephalhematoma (Calcified) • Chronic Subdural Hematoma • Osteomyelitis (Chronic)

( alcified)

Rare but Important • Osteosarcoma • Osteochondroma • Frontometaphyseal Dysplasia • Osteopetrosis • Osteopathia Striata

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Focal cortex t ± diploic expansion • Look for associated dural lesion Helpful Clues for Common Diagnoses • Hyperostosis Frontalis Intema o Middle-aged, older women o Bilateral, symmetrical (bifrontal) o Overgrowth mostly inner table o Ends at coronal suture • Meningioma o Three patterns

Hyperostosis

I 1

Sagittal T 1 WI MR shows a typical example 01 local skull thickening lrom benign hyperostosis Note that the thickening

12

Frontalis Interna

stops at coronal

suture

=. =.

• Sclerotic: Dural-based mass, adjacent calvarium thickened, ± dural tail • lntradiploic: lntradiploic mass thickens, expands calvaria ± cortical d estru ction/thicken ing • "En plaque": Nodular dural thickening + associated extensive hyperostosis (juxta-orbital most common site) • Metastasis (Osteoblastic) o Common with prostate, breast metastasis o Look for associated focal/diffuse dura-arachnoid involvement Helpful Clues for Less Common Diagnoses • Fibrous Dysplasia o Young patient o Medullary expansion ("ground-glass") • Paget Disease o Late osteosclerotic phase o Focal areas of sclerosis in expanded diploic space ("cotton wool" appearance) • Dyke-Davidoff-Masson o Cerebral atrophy + ipsilateral compensatory osseous hypertrophy & hyperpneumatization of paranasal sinuses • Cephalhematoma (Calcified) o Birth trauma, subperiosteal hemorrhage o Early: Thin calcified shell, late sequelae: Incorporation of the calcified rim into the outer table of the skull • Chronic Subdural Hematoma (Calcified) o Chronic calcified SDH along inner table simulates thick skull o Looks like "double" skull on MR

Meningioma

Sagittal T1WI MR shows an intradiploie meningioma 81 with a massively thickened calvarium ~

THICK SKULL, LOCALIZED III

::l

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...

D) III

Fibrous Dysplasia (Left) Axial CECT shows localized hypemslOsis B>' with associated enhancing dural-based soft tissue ~ in pmstate metastasis. (Right) Axial bone CT shows well-de(ined focal calvarial thickening with gmund-g/ass appearance characteristic

:::l

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=-

for fibrous

dysplasia.

Paget Disease

Dyke-Davidoff-Masson (Left) Axial bone CT shows both lytic and blastic Paget disease as evidenced by focal lysis with sclemtic diploic expansion and thickened cortices EB. (Right) Axial bone CT shows left fmntal calvarial thickening with over

=

=

pneumatization

of the frontal

sinus E1 in Dyke-Davidoff-Masson.

Cephalhematoma

(Calcified)

Chronic Subdural Hematoma (Calcified) (Left) Axial CECT shows localized skull thickening due to a calcified cephalhemalOma SlI. (Right) Axial T2WI MR shows an

unusual appearance resembling a "double skull". Outer dark lines Ei:I are outer table, while the middle dark line ~ represents inner table; the intervening area is marrow.

Note additional

crescentic area deep

£0

table demarcated by an unusual third black line This represents an old calcified

chronic

hematoma.

inner

=.

subdural

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THIN SKUll, GENERALIZED

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DIFFERENTIAL DIAGNOSIS

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Common • Normal Infant Skull • Obstructive Hydrocephalus • Aqueductal Stenosis Less Common • Lacunar Skull • Hyperparathyroidism • Hypophosphatasia Rare but Important • Rickets • Osteogenesis Imperfecta • Cleidocranial Dysplasia • Primordial Dwarfism

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Gradual calvarial thinning: Chronic t ICP (e.g., aqueductal stenosis) • Demineralization: Hyperparathyroidism • Poor ossification o Hypophosphatasia, rickets o Osteogenesis imperfecta Helpful Clues for Common Diagnoses • Normal Infant Skull o Newborn: Vault thin, comprised of membranous bone o Parietal bones thin, often barely visible o Frontal, occipital bones more ossified o Severe underossification common in premature infants

• Obstructive Hydrocephalus o Etiology can be intra- or extraventricular o Unless shunted -+ skull gradually thinned • Aqueductal Stenosis o Lateral, 3rd ventricles t, 4th normal Helpful Clues for Less Common Diagnoses • Lacunar Skull o Membranous bone dysplasia -+ thin bone • Thinned calvarium is developmental, NOT caused by hydrocephalus • Resolves spontaneously by age 6 months although minor residua may persist into adulthood o Associations • Chiari 2, myelomeningocele ± encephalocele • Hyperparathyroidism o Osteopenia + cortical thinning o "Salt and pepper" calvarium o t Parathyroid hormone • Hypophosphatasia o Serum alkaline phosphatase ~ o Decreased ossification of skull, vertebrae • Skull may be "boneless" • Short tubular bones poorly/irregularly ossified with "frayed" metaphyses (similar to rickets) Helpful Clues for Rare Diagnoses • Osteogenesis Imperfecta o Osteoporosis + osseous fragility o Multiple fractures o Thin cortex, ~ ossification BOS o Multiple wormian bones

Normal Infant Skull

I 1 14

Axial bone CT shows normal generalized thin calvarial bones in a newborn E!:I with mildly overfapping sutures.

Axial NECT shows massively dilated ventricles in chronically obstructed hydrocephalus associated with diffuse thinning of calvarium E:I.

THIN SKULL, GENERALIZED III

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Lacunar Skull

III

Lacunar Skull (Left) Late,al ,adiograph in a patient with Chiari 2 malformation

shows the

typical appearance of "lacunar" skullEz, also known as Luckenshadel. (Right) Axial bone CT in the

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c

same patient shows a characteristic in Chiari

Hyperparathyroidism

2

"lacunar" skull

malformation.

Hypophosphatasia (Left) Anteroposterior radiograph in a 13 year old with parathyroid adenoma shows demineralization and generalized thinning of the skull Note the subtle "saIL and pepper"

=.

appearance

of the calvarium

~ (Right) Lateral radiograph shows the hypomineralized, markedly thin skull of a newborn

=

with infantile

hypophosphatasia.

Cleidocranial

Dysplasia (Left) Anteroposterior radiograph of a skull shows a classic "boneless" skull in osteogenesis imperfecta. Ossification of only the facial bones and two small regions of the cranium

It] is present.

(Right) Bone CT with 30 shaded surface display shows generalized

calvarial

thinning with multiple wormian

bones in and

around lambdoid

suture.

I 1 15

THIN SKULL, LOCALIZED

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Common • Skull Normal Variants o Parietal Thinning o Squamous Temporal, Occipital Bones • Arachnoid Cyst • Mega Cisterna Magna Less Common • Slow Growing Neoplasm o Oligodendroglioma o D ET o Ganglioglioma o Diffuse Astrocytoma, Low Grade • Paget Disease • Scalp Lesions o Dermoid Cyst o Epidermoid Cyst o Neurofibroma Rare but Important • Meningioma • Linear Scleroderma

(Coup de Sabre)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Evaluate underlying brain, overlying scalp! Helpful Clues for Common Diagnoses • Skull Normal Variants o Parietal, squamous thinning o Inner table intact; diploe, outer table thin • Arachnoid Cyst o Well-delineated CSF-like extra-axial mass

Parietal Thinning

I 1 16

Axial bone CT shows classic symmetric biparietal thinning II] Lhai is striking but normal.

Pressure erosion of adjacent calvarium 050-65% middle fossa; 5-10% convexity • Mega Cisterna Magna o Enlarged cisterna magna & intact vermis, normal cerebellar hemispheres o Scalloped occipital squamae o

Helpful Clues for Less Common Diagnoses • Slow Growing Neoplasm o Any cortically based slow growing neoplasm can cause inner table scalloping o Oligodendroglioma • Partially Ca++ cortical/subcortical mass o DNET • Young patient, chronic epilepsy • "Bubbly" cortical mass o Ganglioglioma • Partially cystic enhancing mass (child/young adult) o Diffuse Astrocytoma, Low Grade • White matter> cortex, nonenhancing • Paget Disease o "Osteoporosis/osteolysis circumscripta" o Early destructive phase • Well-defined lysis; frontal> occipital • Both inner, outer tables involved (inner usually more) • Scalp Lesions o Pressure erosion of outer table o Dermoid, epidermoid cysts; neurofibroma Helpful Clues for Rare Diagnoses • Meningioma o Can erode, invade, destroy calvarium

Arachnoid

Cyst

Axial NECT shows a typical arachnoid cyst with localized thinning of the adjacent calvarium =:iI.

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III

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(Left) Sagittal T I WI MR

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thinning

of the adjacent

occipital

bone lID. Vermis

and fourth ventricle

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normal. (Right) Axial T/ C+ MR shows a nonenhancing low signal intensity oligodendroglioma in the left frontal region

=

associated

with subtle thinning 01 the left frontal bone 81 as compared to the right.

(Left) Axial T2WI MR shows

a very classical appearance of a well-delineated cortically based "bubbly" mass, a ONET8I. Note focal cortical thinning ~. (Righi) Axial T2WI MR shows a lobulated cortically based ganglioglioma -7 causing localized

thinning

of

the skull 81.

(Left) Lateral radiograph

shows osteoporosis a specific appearance in early Pagel disease of the skull 81. (Right) Coronal J 1 C+ MR shows an atypical circumscripta,

meningioma

with solid and

cystic components

invading

the SSS81 with associated focal thinning of the calvarium c::£

I 1 17

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DIFFERENTIAL DIAGNOSIS

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Common • Skull Normal Variants • Surgical Defects, Calvarial o Burr Holes o CSF Shunts and Complications • Metastasis Less Common • Epidermoid Cyst • Langerhans Cell Histiocytosis • Plasmacytoma • Paget Disease • Hemangioma • Dermoid Cyst • Fibrous Dysplasia • Leptomeningeal Cyst • Osteomyelitis Rare but Important • Cephalocele • Tuberculosis • Neurosarcoidosis • Sinus Pericranii • Aneurysmal Bone Cyst • Aggressive Fibromatosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Margins of lytic lesion helpful o Surgical defects: Well-marginated o Metastasis, osteomyelitis: Permeative o Epidermoid: Dense sclerotic o Histiocytosis: "Beveled" edge

I 1 18

Helpful Clues for Common Diagnoses • Skull Normal Variants o Vascular grooves • Inner table: Meningeal arteries, veins • Outer table: Superficial temporal artery o Venous channels • Thin-walled veins, venous "lakes" • Connect meningeal veins/dural venous sinuses with pericranial veins • Diploic venous channel can usually be traced into venous lakes o Pacchionian (arachnoid) granulations • Within/adjacent to dural venous sinus • Round/oval filling defect in venous sinus • Large lesions remodel inner table • CSF density/signal intensity

• Surgical Defects, Calvarial o Check history! o Burr holes, surgical defects well-marginated • Metastasis o Destructive, permeative o Enhancing mass centered in diploe o ± Associated dural/scalp soft tissue o Often known primary malignancy • Breast, lung, prostate most common Helpful Clues for Less Common Diagnoses • Epidermoid Cyst o Involves both inner, outer tables o Well-defined o Lacks central trabeculae o Dense sclerotic margins o Typically round or lobulated o Restricts (hyperintense) on DWI • Langerhans Cell Histiocytosis o "Eosinophilic granuloma" o Well-defined lytic lesion o "Beveled" edge (inner table involved> outer) o No marginal sclerosis o ± Adjacent soft tissue mass 0<5 years o "Hole within hole", "button sequestrum" on ECT • Plasmacytoma o Lytic lesion with scalloped, poorly marginated, non-sclerotic margins o Often large at presentation o Biconvex expansion of involved bone • Paget Disease o Lytic phase: Well-defined lucent defect o "Osteoporosis circumscripta" o Frontal> occipital o Inner & outer tables both involved; inner usually more o Cortical thickening, coarse trabeculation hypointense Tl/T2WI • Hemangioma o Lytic diploic space lesion o Well-circumscribed o "Spoke wheel" or "reticulated" pattern o Strong enhancement • Dermoid Cyst o Well-circumscribed unilocular cyst containing fat o Expands diploe

(J)

LYTIC SKULL LESION, SOLITARY

Commonly near the anterior fontanelle, glabella, nasion, vertex, subocciput • Leptomeningeal Cyst o "Growing fracture" on radiography/NECT o Late complication of skull fracture with dural laceration o Smoothly marginated skull defect o Hyperintense on T2WI • Osteomyelitis o Usually complication of trauma, sinusitis, mastoiditis o Frontal> temporal bone o Mixed lytic/proliferative lesion o Moth-eaten/permeative medullary & cortical destruction o "Pott puffy tumor" = frontal soft tissue swelling o Often associated: Epidural abscess! o

Helpful Clues for Rare Diagnoses • Cephalocele o Herniation of brain, meninges, CSF,or a combination of all three o Dural laceration + dehiscent skull defect o Can be congenital or acquired (surgery, trauma) • Congenital: Parietal, occipital; young patient • Acquired: Basifrontal, history of trauma/su rgery • "Atretic cephalocele" should be in differential diagnosis of any midline subscalp mass in child, especially parietal region

Skull Normal Variants

c: "

• Neurosarcoidosis o Isolated area of bone translucency • Well-demarcated margins o Uncommon presentation o Look for associated • Pituitary/infundibulum, dural-based masses • Hilar adenopathy (CXR) • Sinus Pericranii o Vascular scalp mass communicates with dural venous sinus via transcalvarial vein o Transcalvarial vein courses through well-defined bone defect o Common frontal (40%) o Midline or paramedian o Superior sagittal sinus most commonly involved • Aggressive Fibromatosis o Benign fibrous tumor of infancy o Solitary/multiple benign myofibroblastic tumors • Subcutaneous tissue, muscle, bone, occasionally viscera • Neck lesions may extend intracranially o Well-defined lytic lesion with/without sclerotic rim o Can mimic any malignant or aggressive infection! o May need biopsy

Coronal 3D NEG shows a burr hole .-7, shunt tubing Ell in this patient with history of myelomeningocele and

& veins

Chiari 2 malformation. Premature closure of the right corona/suture is a/50 present

arachnoid granulations

a norma/thinning

" c

Burr Holes

Sagittal NECT - 3D VRT display of normal inner calvarial vault shows vascular groove for middle meningeal artery of squamous temporal bone!CB

(f)

I 1 19

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Epidermoid Cyst

(Lefl) Axial bone CT shows a Iylic skull lesion with irregular margins in a lung carcinoma metastasis t:2S. (Right) Laleral radiograph of skull shows an epidermoid cyst presenting as a well-defined lytic lesion with

dense sclerotic margins 81.

Langerhans Cell Histiocytosis (Left) Axial NECT shows an epidermoid cyst presenting as a well-defined lytic lesion with dense sclerotic margins SI. (RighI) Axial NECT shows a large destructive lesion with associated soft tissue mass in a patient with Langerhans cell histiocytosis

SI.

Plasmacytoma (Left) Axial bone CT shows a typical appearance of plasmacytoma involving the petrous apex, inner ear, and

clivus =:I. (RighI) Axial bone CT shows bOlh lytic and blastic Paget disease as evidenced by focal lysis =:I within a background of diffuse sclerotic diploic expansion and thickened

cortices

I 1 20

Paget Disease

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LYTIC SKULL LESION, SOLITARY

III

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Hemangioma

m ...

Dermoid Cyst

III

(Left) Axial bone CT shows a sharply marginated expansile hemangioma

with

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Q)

reticulated intra diploic trabecular thickening SII. (Right) Coronal bone CT shows a fat density lytic lesion involving the

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<:

sphenoid, consistent with a dermoid cyst

Fibrous Dysplasia (Left) Axial bone CT shows a variant case of mixed lucent and sclerotic SII ("Pagetoid") fibrous dysplasia affecting the left frontal bone. (Right) Axial bone CT shows a defect in the skull with herniation of dura in a posHraumalic leptomeningeal cyst

=

=.

Osteomyelitis

Sinus Pericranii (Left) Axial bone CT shows a permeative

pallern

of

destruction in (rontal osteomyelitis E.J with an associated scalp swelling (Right) Coronal T1 C+ MR shows a subcutaneous enhancing mass

rs

=.

=

communicaling lranscalvarial

with

a

vein ~

through a well-delineated, corticated skull defect SII.

I 1 21

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DIFFERENTIAL DIAGNOSIS

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Common • Skull Normal Variants o Venous Lakes o Emissary Veins, Transcranial o Arachnoid Granulations o Prominent Convolutional Markings o Parietal Foramina • Treatment-Related o Burr Holes o Surgical Defects, Calvarial • Metastases, Skull • Osteoporosis • Myeloma Less Common • Langerhans Cell Histiocytosis • Hyperparathyroidism • Lymphoma, Metastatic, Intracranial • Hemangioma • Leukemia • Osteomyelitis, Skull • Osteoradionecrosis • Chiari 2 (Lacunar Skull) Rare but Important • Neurosarcoid • Neurofibromatosis Type 1 (Lambdoid Defects) • Syphilis, Acquired

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • As with solitary lucent skull lesion, margins helpful o Sharply demarcated: Treatment-related, myeloma o Permeative: Metastasis, osteomyelitis o Beveled: Histiocytosis o Inner table involvement: Convolutional markings, arachnoid granulations

I 1 22

Helpful Clues for Common Diagnoses • Skull Normal Variants o Venous Lakes • Diploic venous can usually be traced to area of lucency • Slightly ragged configuration, poorly defined margin o Emissary Veins, Transcranial • Extremely variable positions

• Common in frontal and parietal bones • Very thin walls • Communicate with meningeal veins and dural sinuses o Arachnoid Granulations • Punched out defects inner table subjacent to dural venous sinuses • CSF density/intensity o Prominent Convolutional Markings • Related to pulsation of brain • Inner table, frequent in children • Become prominent in craniosynostosis, chronic raised intracranial pressure o Parietal Foramina • Two symmetric openings on each side of sagittal suture in the upper edge of parietal bones • Usually very small, permit passage of emissary veins • Treatment-Related o Burr holes, shunt-related, surgical defects o Sharply marginated • Metastases, Skull o Permeative skull destruction ± scalp/dural soft tissue o Often known primary malignancy o Commonly lung, breast, renal, thyroid • Osteoporosis o Older age group o Spotty demineralization appearing as lucent lesions • Myeloma o Multiple, well-circumscribed, lytic, punched out, round lesions o Skeletal survey helpful Helpful Clues for Less Common Diagnoses • Langerhans Cell Histiocytosis o Sharply marginated lytic defect with bevelled margins o Associated soft tissue mass o Large lesions: Geographic destruction o Brain: Thick enhancing infundibulum, absent posterior pituitary bright spot o 2-5 years: Multifocal disease • Hyperparathyroidism o Mottling of the cranial vault due to trabecular bone resorption o Alternating areas of lucency and sclerosis: "Salt and pepper" skull o Brown tumors: Multiple well-defined lytic lesions

en

MULTIPLE LUCENT SKULL LESIONS

Parathyroid hormone • Hemangioma o Sharply marginated expansile lesion o Diploic space, honeycomb, or sunburst appearance pattern o 1/3 have thin sclerotic rim o Multiple uncommon • Leukemia o Osteopenia with multiple lytic lesions o Sutural diastasis: Produced by t intracranial pressure o Tubular and flat bones more commonly involved o Skeletal survey may be helpful • Osteomyelitis, Skull o Permeative destruction ± scalp/epidural soft tissue o Usually occurs as a complication of trauma or sinusitis o Brain abscess is most common complication • Osteoradionecrosis o Mixed region of lysis and sclerosis o Radiates outward from epicenter of radiation portal • Chiari 2 (Lacunar Skull) o Caused by inherited mesenchymal defect, not hydrocephalus/increased intracranial pressure o Not same as prominent convolutional marklngs (normal variant) o Present at birth, largely resolves by 6 months o Minor changes may persist into adulthood o t

Venous lakes

o o

c" :

Involves both inner, outer tables Squamous portions of temporal/occipital bones, parietal bones

III

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Helpful Clues for Rare Diagnoses

• Neurosarcoid o Uncommon o Well-circumscribed lytic lesion o Involves inner, outer tables of calvarium o Sharp, non-sclerotic margins • Neurofibromatosis Type 1 (Lambdoid Defects) o Lambdoid suture defect o Associated sphenoid wing dysplasia o Plexiform neurofibromas of scalp, orbit common • Syphilis, Acquired o Lytic areas with demineralization/sclerosis of the outer table, diploe o Inner table less involved o Irregular worm-eaten osseous destruction o Associated presence of mucocutaneous findings or generalized lymphadenopathy

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SELECTED REFERENCES 1. 2. 3. 4.

5.

Connor SE et al: Imaging of the petrous apex: a pictorial review. Br J Radiol. 81(965):427-35, 2008 Porto Let al: Central nervous system imaging in childhood leukaemia. Eur J Cancer. 2004 Smith JK et al: Imaging manifestations

of neurosarcoidosis.

AJR Am J Roentgenol. 182(2):289-9S, 2004 Hasegawa M et al: Multicentric infantile myofibromatosis in the cranium: case report. Neurosurgery. 36(6): 1200-3, 1995 Zimmerman RD et al: Cranial CT findings in patients with meningomyelocele. AJR Am J Roentgenol. 1979

Emissary Veins, Transcranial

I Axial bone CT shows multiple linear lucent areas ~ due to prominent emissary veins. Note a fromal venous lake E:I with small venous tributaries It].

Axial bone CT shows small lucent foci in diploic space I:l:l. All could be traced traversing skull on multiple sections. findings are typical for emissary veins seen

"endon".

1 23

=

MULTIPLE LUCENT SKULL LESIONS

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co

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c:

•.. al III

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c:

III

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Arachnoid

Granulations

(Left) Coronal bone CT shows a large arachnoid granulation of the central skull base~. CECT scan (not shown) demonstrated CSF within the lucent defect. (Right) Lateral radiograph in a 6 year old shows prominent

convolutional

markings ~ Note that the sella ~ is normal, without enlargement or erosion to suggest increased intracranial pressure.

Parietal Foramina (Left) Anteroposterior radiograph shows large symmetric lytic areas in the parietal bones, consistent with a large parietal foramina ~ (Right) Coronal oblique 30 NECT shows a burr hole ~ with shunt tubing ~

Surgical (Left) Axial CECT in a patient with pterional approach anterior tempora/lobectomy shows surgical defects in

squamous temporal bone ~. Remote cerebellar hemorrhage ~ occurred a complication of the procedure. (Right) Axial bone CT shows multiple areas of permeative destruction -7 in the calvarium

of

a

patient

breast carcinoma

I 1 24

as

with

metastasis.

Defects,

Calvarial

Burr Holes

MULTIPLE LUCENT SKULL LESIONS III

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Osteoporosis

.,

Myeloma

III

(Left) Axial bone CT shows ill-defined areas of demineralization

=

in

osteoporosis. Lesions do not destroy bone; entire diploic space appears moderately deossified. (Right) Axial bone CT shows multiple punched out defects ~ in the calvarium

in a

patient

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c "

with

multiple myeloma.

Langerhans Cell Histiocytosis

Hyperparathyroidism (Left) Axial bone CT shows bilateral mastoid destructive lesions in a patient with Langerhans cell histiocytosis ~. (Right) Lateral radiograph shows a pattern of trabecular resorption of mixed lytic Ii8 and dense areas ~ that has been termed "salt and pepper" in hyperparathyroidism.

Chiari 2 (Lacunar Skull) (Left) Axial T t C+ MR shows multiple enhancing lesions E:I in a patient with multiple calvarial hemangiomas. (Right) Lateral radiograph shows the typical appearance of "/acunar" skull a/50 known as Luckenschadel, involving inner & outer tables of squamous bones and due to mesenchymal defects, not hydrocephalus.

I 1 25

SClEROTIC

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Common • Metastasis • Osteoma • Fibrous Dysplasia • Meningioma-Associated • Paget Disease

Hyperostosis

less Common • Osteomyelitis, Skull (Chronic) • Calcified Cephalohematoma Rare but Important • Calvarium Fracture (Chronic, Depressed) • Meningioma (Intraosseous) • Hemangioma • Craniostenosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Outer/inner table: Osteoma • Diploic space (DS) ± outer/inner table: Sclerotic metastasis • DS expansion + outer> inner table: FD • DS expansion + inner> outer table: Paget disease

I 1 26

Helpful Clues for Common Diagnoses • Metastasis o Most common tumors with intrinsically sclerotic metastases • Prostate • Breast • Lymphoma o Any lytic metastasis can become sclerotic after treatment o Use contrast-enhanced MR to assess intracranial involvement • Osteoma o Well-circumscribed, dense, hyperostotic o Location • Paranasal sinuses (frontal most common) • Calvarium • Facial bones, mandible o Outer table> inner table • Fibrous Dysplasia o 70% of all FD cases are monostotic o Expansile, widened diploic space o Imaging patterns relate to relative content of fibrous vs. osseous tissue • Classic: "Ground-glass" appearance

• Sclerotic, cystic, or mixed bone changes also seen • Can show variable enhancement, sometimes striking • Meningioma-Associated Hyperostosis o More common with en plaque meningioma than globular form o En plaque meningioma • Adjacent bony hyperostosis often disproportionately greater than underlying tumor o Cause of hyperostosis is controversial • Reactive or tumoral infiltration • Paget Disease o Older patient (vs. younger with fibrous dysplasia) o Late sclerotic phase • Widening of diploic space + coarsened trabeculae • Inner table, diploic space more involved than outer table • Round or oval area of sclerosis (usually within prior areas of "osteoporosis circumscripta") • Diffuse> > solitary involvement Helpful Clues for less Common Diagnoses • Osteomyelitis, Skull (Chronic) o Rare in calvarium • Classic imaging finding = "button sequestrum" • Dense island of dead bone within well-defined lytic area • Also seen in numerous other entities • Common: Eosinophilic granuloma, healing burr hole • Less common/rare: Tuberculous osteitis, radiation-induced bone necrosis, metastasis, Paget disease o More common in skull base • Spread of infection from paranasal sinuses, mastoid, petrous apex air cells • Ill-defined area of mixed osteosclerosis, lysis o ± Epidural/subdural empyema, brain abscess o Consider contrast-enhanced MR to assess extent • Calcified Cephalohematoma o Usually associated with birth trauma • Acute subperiosteal hemorrhage

SClEROTIC

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SKULL LESION, SOLITARY

C

o

• Healing stage may result in rim calcification Late sequelae • Calcified rim incorporated into outer table • Outer table eventually becomes sclerotic, thickened

Helpful Clues for Rare Diagnoses

• Calvarium Fracture (Chronic, Depressed) o Rare • Most depressed skull fractures are elevated, repaired o May have associated cephalocele with bony reaction (lysis> sclerosis) • Meningioma (Intra osseous) o Primary calvarial meningiomas rare • 1-2% of all meningiomas • Sometimes termed "ectopic" or "extradural" meningioma • Best term = primary extradural meningioma o Classification • Purely extracalvarial (type 1) • Purely calvarial (type 2) • Calvarial with extracalvarial extension (type 3) o Typical presentation • Middle-aged, older patient • Slow growing scalp swelling ± pain o Focal skull mass • Diploic space enlarges • Mixed lysis, sclerosis; lysis often predominates

• Can mimic metastasis • Hemangioma o Osseous hemangiomas of calvarium account for 0.2% of bone neoplasms o Benign vascular anomalies of bone o Expand diploic space, outer> inner table o Most are lytic, some sclerotic (rim) with "sunburst" appearance o Highly vascular • Variable histology • Can be venous, cavernous, or capillary type o ± Intracranial extension o ± Dural "tail sign" o Can mimic meningioma • Craniostenosis o Premature suture fusion o One of most common craniofacial anomalies o Can be syndromic (over ISO associated) or nonsyndromic • Usually isolated (nonsyndromic) o Sagittal suture most commonly affected o Dense suture "bone bridge" or "beaking"

III

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,.c Ul

SELECTED REFERENCES 1. 2. 3.

Ilukki J et al: Single suture craniosynostosis: diagnosis and imaging. Front Oral BioI. 12:79-90,2008 Agrawal Vet al: lntraosseous intracranial meningioma. AJNR Am J Neuroradiol. 28(2):314-5, 2007 Tokgoz N et al: Primary intraosseous meningioma: CT and MRI appearance. AJNR Am J Neuroradiol. 26(8):2053-6, 2005

Metastasis

I Axial bone CT shows a sclerotic metastasis from prostate carcinoma HJ that involves the diploic space as well as the inner table.

Axial bone CT shows a solitary sclerotic metastasis E> from breast carcinoma. This could also possibly have been a lytic metaSlasis that has been treated and become scleroUc.

1 27

SClEROTIC

SKULL LESIONr SOLITARY

a. OJ U

(fJ C 1tI

~

co

"C C 1tI

Osteoma

Osteoma (Left) Axial bone CT shows a classic large osteoma arising from the outer table of the occipital bone 81. (RighI) Axial bone CT shows an osteoma ~ arising from the inner table of the frontal

bone. Osteomas arise more commonly from the outer rather than the inner table.

Fibrous Dysplasia (Lefl) Axial bone CT shows a wel/-defined focal calvarial thickening with ground-glass appearance characteristic for fibrous dysplasia (RighI) Axial NECT shows an example of cystic fibrous dysplasia of the superior orbital rim. Note lucent cavity c;. surrounded by thick sclerotic rind l~ and the lucent rim 8

=.

Meningioma-Associated (Lefl) Axial bone CT shows focal hyperostosis associated with an en plaque meningioma 81. (RighI) Axial bone CT shows mostly late-stage thickening, sclerosis of temporal bone with a few scattered lytic

areas=.

I 1 28

Hyperostosis

Paget Disease

SCLEROTIC SKULL LESION, SOLITARY III

:J

0-

ro ., Osteomyelitis,

Skull (Chronic)

Osteomyelitis,

III

Skull (Chronic) (Left) Axial bone CT shows classic" bullon sequestrum" as a residual of chronic calvarial osteomyelitis. Note peripheral dense bony sclerosis 1m surrounding dense "sequestrum" E'J of dead bone within well-defined lucenl area. (Right) Axial bone CT in a patienl with a long history of ear infections shows typical appearance of chronic otitis media wilh malleus 1::1 and incus 81 surrounded by inflammatory

:J (JJ

o

Cl -0

(JJ

c ""

debris. Note

overlying calvarial sclerosis, thickening ffi

Calcified

Cephalohematoma

Meningioma

(Intraosseous) (Left) Axial bone CT shows calcified cephalohematoma

E'J with calcified rim incorporated into outer table of skull. (Rigl1t) Axial bone CT shows thick left frontal bone with lobulated hyperostosis 1::1 extending from outer lable. SoFt tissue

mass overlies hyperostosis

81. MR (not shown) demonstrated hyperostosis infiltrating, expanding diploic space. Primary inlraosseous meningiomas originate within diploic space, may extend both intra- and eXlracranially.

Hemangioma (Left) Axial bone CT shows a focaf expansile calvarial mass with well-delineated sclerotic margins d>, (Right) Axial NECT shows scferosis and fusion of metopic suture thaI caused a "keel-shaped" forehead (trigonocephaly) in this 7 month old infant.

=

I 1 29

SCLEROTIC

SKUll

nl

"-

lD "0

c: nl

Common • Metastases, Skull less Common • Fibrous Dysplasia • Paget Disease Rare but Important • Hyperparathyroidism • Osteoma • Osteopoikilosis • MeJorheostosis • Osteopathia Striata

("Brown Tumor")

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Osteoblastic metastasis, especially from prostate, by far the most common cause Helpful Clues for Common Diagnoses • Metastases, Skull o Osteoblastic or treated • Most common = prostate carcinoma • Any lytic metastasis following favorable response to treatment o Other malignancies with sclerotic metastases include breast, colon, melanoma, bladder, soft tissue sarcoma Helpful Clues for less Common • Fibrous Dysplasia o 20-30% polyostotic

Diagnoses

30

Axial bone CT shows multiple sclerotic metastases from prostate carcinoma.

Frontal, sphenoid, maxillary, ethmoid bones more commonly involved o Widened diploic spaces with outer table> inner table involvement o Ground-glass or sclerotic appearance • Paget Disease o Late osteosclerotic phase o Blastic lesions, often crossing sutures o "Tam-o'-shanter" skull: t t Diploic space, particularly inner table o "Cotton wool" skull: Focal areas of sclerosis within previous areas of osteoporosis circumscripta Helpful Clues for Rare Diagnoses • Hyperparathyroidism ("Brown Tumor") o Trabecular bone resorption in cranial vault o Alternating areas of lucency and sclerosis: "Salt and pepper" appearance o Brown tumors: Can become ossified during reparative process • Osteoma o In Gardner syndrome, multiple osteomas • Round dense lesions of outer table (less common in inner table) o Colonic polyposis + soft tissue tumors (especially desmoid) • Osteopoikilosis o Sclerosing bone dysplasia • Multiple radiopaque round, oval, or lanceolate spots of t radiodensity o Predilection for epiphysis/metaphysis in long and short tubular bones o Skull involvement rare

Metastases, Skull

Metastases, Skull

I 1

MULTIPLE

o

DIFFERENTIAL DIAGNOSIS c:

lESIONS,

=

=

Axial bone CT in a patient with lung carcinoma shows mixed lytic, sclerotic calvarial metastases with adjacent ossific foc; E!2 from destroyed bone ;n

adjacent dural soft tissue masses.

SCLEROTIC SKULL LESIONS, MULTIPLE III

:J

Co

..,

OJ

Fibrous Dysplasia

III

(Left) Axial bone CT shows mulliple lesions of classic polyostolic fibrous dysplasia H2 with expansion and ground-glass matrix. (Right) Axial bone CT shows mixed

:J (j) ()

OJ -0

sclerotic, lucent process af(ecting sphenoid bone, leFt

maxilla. Maxillary sinus lumen is obliterated PlIiJ; leFt pterygomaxillary Fissure~ is

narrowed.

Paget Disease

Paget Disease (Left) Lateral radiograph shows a classic appearance

of

Pagel disease,

with

changes consistent with osteoporosis circumscripla H2 and a "COllon wool" appearance due to multiple sclerotic lesions (Right) Axial bone CT shows diFFuse calvaria/thickening

with

multiple sclerotic areas 11:.'I in a background of osteolysis in a palient with Paget disease.

Osteoma (LeFt) Coronal bone CT shows generalized skull thickening secondary to chronic renal insufficiency and secondary hyperparathyroidism. Note the Focal areas of osteosclerosis 8:1. (Right) Anteroposterior radiograph shows large osteomas =::l. I-Iere, they are part of Gardner syndrome. This patient a/so has a long history of polyposis of the colon.

I 1 31

MACROCEPHALY n.

ro

u

DIFFERENTIAL DIAGNOSIS

CI)

c: III

•...

a:l "'0

c: III

::::J

-" en

Common • Benign Familial Macrocrania • Hydrocephalus and Obstructed CSF Spaces o Intraventricular Hemorrhage o Aqueductal Stenosis o Arachnoid Cyst o Enlarged Subarachnoid Spaces o Villous Hypertrophy of the Choroid Plexus o Subdural Hematoma, Chronic Less Common • Dandy-Walker Continuum • Neoplasm o Glioblastoma Multiforme o Teratoma • Neurocutaneous Disorders o Neurofibromatosis Type 1 o Tuberous Sclerosis Complex • Hemimegalencephaly • Megalencephaly Syndromes Rare but Important • Hydranencephaly • Inborn Errors of Metabolism o Glutaric Aciduria Type 1 o MLCI o Mucopolysaccharidosis o Alexander Disease o Canavan Disease • Achondroplasia • Fibrous Dysplasia

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Macrocephaly = head circumference> 2 standard deviations above mean for age-matched controls • Macrocephaly = macrocrania • Megalencephaly = subtype of macrocrania • Imaging infants/children with macrocephaly o Hydrocephalus or white matter abnormality found? Use contrast! • Glutaric aciduria type 1 = child abuse mimic

I 1 32

Helpful Clues for Common Diagnoses • Benign Familial Macrocrania o Family history important • Intraventricular Hemorrhage o Hemosiderin not always apparent on follow-up images

• Aqueductal Stenosis o Look for associated hemosiderin, vascular anomalies • Arachnoid Cyst o Steady-state acquisition sequence to identify cyst wall • Enlarged Subarachnoid Spaces o Look for traversing veins o Natural history: Resolution by 12-18 months • Villous Hypertrophy of the Choroid Plexus o Likely on a spectrum, including choroid plexus papilloma o Bilateral choroid plexus lesions typical • Subdural Hematoma, Chronic o MR identifies hemorrhagic components Helpful Clues for Less Common Diagnoses • Dandy-Walker Continuum o Classic Dandy-Walker & Blake pouch cyst: Vermian angulation, large bony posterior fossa o Classic Dandy-Walker • Incompletely lobulated vermis, deficient fastigial recess/primary fissure o Blake pouch cyst • Intact vermis, fastigial recess, and primary fissure • Neoplasm o Large, bulky neonatal tumors o Glioblastoma Multiforme • Enhancement, necrosis, hemorrhage o Teratoma • Fat, calcium, enhancing soft tissue • Neurofibromatosis Type 1 o Look for foci of abnormal signal intensity (FASI), optic nerve gliomas, cafe-au-lait spots o Macrocrania predominantly derived from bulky white matter • Tuberous Sclerosis Complex o Cutaneous markers (ash-leaf spots) may be occult in 1st year of life o Look for Ca++ subependymal nodules, radial Iines • Hemimegalencephaly o Look for cutaneous markers & stigmata of overgrowth syndromes • Hypomelanosis of Ito • Proteus syndrome • Linear sebaceous nevus syndrome

en ;J;

MACROCEPHALY

c:

• Megalencephaly Syndromes o Clues in name • Megalencephaly, polymicrogyria syndrome • Megalencephaly with dilated Virchow-Robin spaces • Cerebral gigantism (Soto syndrome) • Macrocrania-cutis marmorata telangiectatica congenita Helpful Clues for Rare Diagnoses • Hydranencephaly o Distinguish from maximal hydrocephalus o MR shows cortex, falx • Glutaric Aciduria Type 1 o Bilateral temporal lobe hypoplasia & large sylvian fissures o Resembles bilateral middle cranial fossa arachnoid cysts o Crisis: Caudate, putamen, globus paIlidus swelling, & t signal • MLCI o Diffusely t white matter signal o Temporal pole & frontoparietal cysts o Macrocrania differentiates from CMV (common microcephaly) • Mucopolysaccharidosis o Dilated perivascular spaces • Alexander Disease o Enhancement is the key to diagnosis! o Infant: Frontal swelling & t signal & enhancement o Juvenile: Brainstem foci of t signal & enhancement

• Canavan Disease o MRS key: t t NAA • Achondroplasia o Small skull base • Jugular foramina coarctation: CSF drainage impaired • Foramen magnum coarctation: CervicomedulJary compression • Fibrous Dysplasia o Focal or diffuse (leontiasis ossea) may head circumference o Classic radiograph/CT: Ground-glass o MR (T2): Black velvet appearance

::l C. OJ

..• III

::l (J)

n

D> "0

(J)

A

c:

t

SELECTED REFERENCES 1.

2.

3.

4.

5.

Colombani M et al: A new case of megalencephaly and perisylvian polymicrogyria with post-axial polydactyly and hydrocephalus: MPPH syndrome. fur J Med Genet. 49(6):466-71,2006 Groeschel Set al: Magnetic resonance imaging and proton magnetic resonance spectroscopy of megalencephaly and dilated Virchow-Robin spaces. Pediatr Neurol. 34(1):35-40, 2006 D'Ambrosio AL et al: Villous hypertrophy versus c1,oroid plexus papilloma: a case report demonstrating a diagnostic role for the proliferation index. Pediatr Neurosurg. 39(2):91-6,2003 Medina LS et al: Children with macrocrania: clinical and imaging predictors of disorders requiring surgery. AJNR Am J Neuroradiol. 22(3):564-70, 2001 Wilms G et al: CT and MR in infants with pericerebral collections and macrocephaly: benign enlargement of the subarachnoid spaces versus subdural collections. AJNR Am J Neuroradiol. 14(4):855-60, 1993

Hydrocephalus Benign Familial Macrocrania

III

and Obstructed Spaces

CSF

I Sagittal T1WI MR shows a normal-appearing corpus callosum and callosal isthmus E'l gyral pattern, myelin

maturation, and midline

slfuclures

benign familial macrocrania.

Anteroposterior radiograph shows massive macrocrania in a child with untreated hydrocephalus.

1

in this child with

33

MACROCEPHALY

:::>

-><

(f)

a.

ro

u (f)

Hydrocephalus

c: l\l

•...

CD

'tl

c: l\l

and Obstructed

CSF Intraventricular

Spaces

Hemorrhage

(Left) Axial NECT shows massive tri·ventricular hydrocephalus. The choroid plexus dangles in the fluid

=-

and the massa intermedia ~ is stretched thin. (Right) Axial T2WI MR in a 27 week gestational age (corrected)

premature

infant

shows an age-appropriate immature sulcal pattern. There is a small focus of ependymal hemosiderin ~ in the right trigone, a small clot 0:> in the left.

Intraventricular

Hemorrhage

Aqueductal

Stenosis

(Left) Axial T2' CRE MR in an infant born prematurely with shunted hydrocephalus shows evidence of

hemosiderin and volume loss in left caudothalarnic groove 82. Diffuse hemosiderin staining 1::1 of the ependyma follows remote IVI I. (Right) Sagittal T2WI MR shows hydrocephalus and a (unnel-shaped aqueduct of Sylvius ~ The appearance is typical, with the proximal aqueduct splayed and the distal aqueduct closed.

Arachnoid (Left) Sagittal T2WI MR

shows marked hydrocephalus and a 3rd ventricular arachnoid cyst. The wall of the cyst ~ obstructs the proximal aqueduct. Note additional infracerebellar & and retrocerebellar 1::1 loculations. (Right) Axial T2WI MR shows an arachnoid cyst almost completely filling the left

csr

hemicranium.

I 1 34

Note shift of

midline structures and marked calvarial expansion '=;. due to the effect of long-standing pulsation.

csr

Cyst

Arachnoid

Cyst

CIl

MACROCEPHALY

""c:

Villous Hypertrophy of the Choroid Plexus (Left) Coronal ultrasound shows prominent pericerebral subarachnoid fluid. The subarachnoid space (between l:ll and l:llJ measures over 10 mm. Veins

~

traverse the space,

confirming that the fluid is in the subarachnoid, not subdural, compartment. (Right) SagiHal T1 C+ MR shows marked hydrocephalus. There was symmetrical slightly nodular enlargement of the choroid plexus BI in this child. Villous hypertrophy is on a spectrum with CP papilloma.

Subdural Hematoma,

Chronic (Left) Axial FLAIR MR shows bilateral subdural collections BI of differing signal intensities and therefore likely different ages. Collections were nearly isodense on CT (not shown). (Right) SagiHal T2WI MR shows hydrocephalus, patent aqueduct, CSF flow voids fastigial crease I?--l< primary fissure large tegmento-vermian angle, &

a

incomplete

vermian

lobulation. This case is in the continuum between "c1assic Dandy-Walker" and Blake pouch cyst.

Glioblastoma

Multiforme

Teratoma (Left) Axial T2WI MR in a 6 week old infant with macrocrania shows a massive supratentorial low signal mass m with vascular flow voids l:ll. There is obstruction of both foramina of Monro by this lesion with resultant hydrocephalus. A small intraventricular hemorrhage ~ is present. (Right) Sagittal T2WI MR in a newborn shows a complex calcified midline mass Fat, soft tissue were seen on

CT. There is a dorsal cyst ~ and anomalous sinus ICB

I 1 35

MACROCEPHALY

::J

-'" en 0-

ro ()

en c: III

•...

III "C

c: III

Neurofibromatosis

Type 1

(Left) Axial T2WI MR shows bilateral hyperintensE foci in the globus pallidus and visualuaclS 81. Note hyperintensity, slight enlargement of pillars of fornix (Right) Sagillal TlWI MR in a newborn shows extensive radial white matter lines typical of tuberous sclerosis. Prior to myelin maturation these are best seen on TI WI sequences. There are Focal calcifications S':I in subependymal nodules.

=.

=-

Megalencephaly

Syndromes

(Left) Sagittal TI WI MR in a child with cerebral gigantism shows thick corpus callosum without isthmus ~ Note

overgrown cerebellum with impaction of herniated cerebellar tonsils 81 into foramen

magnurn.

(Right)

Coronal T2WI MR shows cerebellum, falx -;>. a tiny amount of occipital brain tissue 0:> along the tentorium.

No other

significant

supratentorial

structures are seen. Thalami (not shown) were present. CSF pulsations led to cranial vault enlargement.

Glutaric (Left) Axial T2WI MR shows prominent sylvian fissures 0:>, reflecting temporal lobe hypoplasia. Note increased signal intensity in caudate heads 81, putamina & globus pallidus !::l during acute metabolic crisis in this child. (Right) Sagillal T2 WI MR shows bulky white maller with markedly abnormal signal. Note temporal lobe ~ frontoparietal cysts E±l near vertex. Large head

=-

circumference

I 1 36

this from CMV

distinguishes

Aciduria

Type 1

Tuberous Sclerosis Complex

MACROCEPHALY Dl ::::s C-

O)

Mucopolysaccharidosis

~ Dl

Alexander Disease (Left) Sagillal T7WI MR shows dilated perivascular spaces 1:12. Callosal and perilrigonal distribution is the most common. (Right) Axial T2WI MR shows a frontal predominance of white maller

signal

::::s [f) (")

OJ -0

increase.

Additionally, the caudate heads ~ and putamina ~ are bright

Alexander Disease

Canavan Disease (Left) Coronal T7 C+ MR shows enhancement

of

=

teardrop-shaped fomiceal columns Sl chiasm and periventricufar

while matter

1:12. Frontal white mailer ~ is hypointense. illustrates

This case

the importance

of

contrast administration in evaluating any unknown while maller

disorder.

(Right) Axial NECT shows diffuse decreased white

=.

matter allenuation Thalami E!;,J are also low in

signal, as this is not a pure leukodystrophy. MRS showed elevated NAA.

Achondroplasia

Fibrous Dysplasia (Lefl) Sagillal T7 WI MR shows prominent pericerebral fluid ~ and typical glabellar indentation 81. The skull base is short, magnum is narrow 1:12. (RighI) Axial T7WI MR in a teen with leontiasis Qssea shows diffuse calvarial and skull base thickening by fibrous dysplasia. There is a typical ground-glass appearance. and the foramen

Note severe narrowing

of the

left lAC 81 and the orbital fissures ~ _

I 1 37

MICROCEPHALY

:J ~ (j)

Cl.

roo

DIFFERENTIAL DIAGNOSIS

(j)

c:

...

t\l

aJ

"0

c: t\l

:J

-'C/)"

Common • Secondary/Acquired from o Hypoxic Ischemic Encephalopathy o TORCH Infections o Nonaccidental Trauma o Meningitis o Fetal Alcohol Syndrome Less Common • Primary/Genetic with o Gyral Simplification o Cortical Dysplasia o Midline Anomaly o Cerebellar Hypoplasia o Hypomyelination Rare but Important • Microlissencephaly • Pseudo-TORCH o Aicardi-Goutieres • Progeroid Syndromes o Cockayne

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Was head circumference ever normal? • Decreased cranio-facial ratio on sagittal view helpful, tape measure best

I 1 38

Helpful Clues for Common Diagnoses • Hypoxic Ischemic Encephalopathy o Patterns helpful, even if no history • Profound: Atrophy, gliosis posterior putamen, lateral thalami, rolandic cortex • Prolonged progressive: Typical watershed encephalomalacia • Mixed: Features of both, ± calcified thalami • TORCH Infections o Agents most frequently causing microcephaly • Cytomegalovirus (CMV) most common by far • Rubella (now rare) o Look for cortical dysplasia, periventricular Ca++, hypomyelination (typically associated with CMV) • Nonaccidental Trauma o History is crucial

BUT look for evidence of trauma/fractures on ALL available films o Brain imaging • Global atrophy or hemiatrophy • Hemosiderin • Meningitis o Early infancy: Group B strep the most damaging • Hypothalamus • Chiasm • Inferior basal ganglia • Diffuse cortex, often asymmetric • Fetal Alcohol Syndrome o Microcephaly • By tape measure or MR volumetrics • Anomalies may occur, but not specific o Diffusion tensor imaging (DTI) reported to show abnormal connectivity o

Helpful Clues for Less Common Diagnoses • Gyral Simplification o Small, grossly normal brain o Looks like "small, but perfect brain" o Corpus callosum may appear thick, lack isthmus • Cortical Dysplasia o Any severe, diffuse dysplasia • Lissencephaly • Pachygyria • Midline Anomaly o Holoprosencephaly, agenesis CC o Assess corpus callosum presence, size, shape • Is there an isthmus? o Holoprosencephaly • Most severe are the smallest • Cerebellar Hypoplasia o May be clue to rare disorders • Microlissencephaly • TUBAIA mutations: Lissencephaly PLUS cerebellar hypoplasia o Assess degree of deficiency • Fastigial recess, primary fissure • Degree of vermian lobulation • Tegmento-vermian angle (is the inferior 4th ventricle open?) • Hypomyelination o May be a clue to rare disorders • Early onset West syndrome with cerebral hypo myelination and reduced white matter

en

MICROCEPHALY

~ c:

• 3-phosphoglycerate dehydrogenase deficiency • Progressive encephalopathy, edema, hypsarrhythmia, optic atrophy (PEHO)

SELECTED REFERENCES 1.

2.

Helpful Clues for Rare Diagnoses

• Microlissencephaly o "Z-shaped" brainstem o Callosal agenesis o Surface often totally smooth o Very small brain • Pseudo-TORCH o Aicardi-Goutieres • Autosomal recessive, important to diagnose • Elevated CSF alpha-interferon • Early onset: TREXI mutation • Late onset: RNASEH2Bmutation • Imaging CMV-like • Ca++ • Hypomyelination • Atrophy • Progeroid Syndromes o Cockayne • Cachectic dwarfism with mental retardation • Disorder of DNA repair • Several mutations known • Lack phenotype-genotype correlation • Facies & neuroimaging progressive • Basal ganglia/dentate Ca++ • Demyelination • Atrophy

3.

4.

5. 6.

7.

8.

9.

Ql

::l Co

..•

Gul A et al: Novel protein·truncating mutations in the

t1J

aspm gene in families with autosomal recessive primary microcephaly. J Neurogenet. 21(3):153-63, 2007 Hassan MJ et al: Previously described sequence variant in CDK5RAP2 gene in a pakistani family with autosomal recessive primary microcephaly. BMC Med Genet. 2007 Kure-Kageyama H et al: A patient with simplified gyral pattern followed by progressive brain atrophy. Brain Dev. 29(6):383-6,2007 Ornoy A et al: Fetal effects of primary and secondary cytomegalovirus infection in pregnancy. Reprod Toxicol. 21(4):399-409,2006 Tang BL: Molecular genetic determinants of human brain size. Biochem Biophys Res Commun. 345(3):911-6, 2006 Sztriha L et al: Extreme microcephaly with agyria-pachygyria, partial agenesis of the corpus callosum, and pontocerebellar dysplasia. J Child Neurol. 20(2):] 70-2, 2005 Abdel-Salam GM et al: Aicardi-Goutieres syndrome: clinical and neuroradiological findings of 10 new cases. Acta Paediatr. 93(7):929-36, 2004 de Vries 15 et al: The spectrum of cranial ultrasound and magnetic resonance imaging abnormalities in congenital cytomegalovirus infection. Neuropediatrics. 3S(2): 113-9, 2004 Riley EP et al: Teratogenic effects of alcohol: a decade of brain imaging. Am J Mod Genet C Semin Med Genet. 127(1):35-4], 2004

Ql

::l (j) (')

III '0 (j)

"

c:

I Coronal fLAIR MR shows cystic encephalomalacia SII

Axial NEeT in a 3 month old infant shows fusion or the

in the border zone distribution in this 3 year old with a

coronal sutures E2 due to severe brain volume loss, shrunken and calcified putamina and thalami ~

history of peripartum prolonged partial asphyxia.

=

following

severe mixed HIE.

1 39

MICROCEPHALY

-'='" (f)

0.

ro

u (f)

TORCH Infections

TORCH Infections

Nonaccidental Trauma

Nonaccidental Trauma

(Left) Axial T2W/ MR shows diffuse white matter

increased signal, periventricufar

calcificaUons

6R periventricular

cysts and diffuse franta/lobe po/ymicrogyria 81 in an

B

infant with confirmed

cytomegalovirus. (Right) Sagittal ultrasound shows perivenlricular

calcifications,

seen here as foci of increased echogenicity =:I. Note peri ventricular cyst E!ll in this patient congenital

of conFirmed

cytomegalovirus.

(Left) Axial FLAIR MR shows diffuse right hemispheric swelling and signal increase, left mesial frontal edema and a right pancake subdural hematoma 81. There is shift

=

of midline

structures

and

compression of the ipsilateral lateral ventricle. (Right) Axial NECT on follow-up in the same child, whose head circumference

is {ailing

below normal, shows right hemispheric volume loss and sulcal widening =:I.

I 1 40

(Left) Axial T2WI MR during the subacute phase of recovery following neonatal group B strep meningitis shows global volume 1055. The left hemisphere 81 is more affected than the right, although both are involved. r ocal necrosis of the globus pallidi =:I and hypothalamus is present. (Right) Axial T2WI MR in the chronic stage in the same infant shows calvarial thickening 81 and global, but asymmetric, volume 105s. Cavitary globus pallidus =:I changes are now

seen.

MICROCEPHALY

(J)

c" : Ql

::s Q.

III ..,

Fetal Alcohol Syndrome

Fetal Alcohol Syndrome

Ql

(Left) Sagiual TI WI MR in a 3 year old with FAS and microcephaly shows only a decreased crania-facial ratio. Microcephaly in fetal alcohol syndrome is easily confirmed by tape measure, as routine anatomic normal.

imaging

::s (j) (')

Q)

"0 (j)

" c

is usually

Volumelrics

and OTi

do, however, show abnormalilies. (Right) Axial T2WI MR in a 39 week fetus shows a few cerebral remnants. Hydranencephaly in this fetus follows exposure to alcohol, smoking, and polydrug abuse.

Gyral Simplification

Gyral Simplification (Left) Sagiual T7WI MR

shows a decreased crania-facial ratio and lack of

a callosal isthmus S1. The brainstem and cerebellum are normal. (Right) Axial T2WI MR shows a relatively normal

appearing

brain.

rlowever, closer perusal reveals mild trigonocephaly !:::I and generalized gyral simplification S1. The myelin maturation

is normal.

(Left) Axial NfeT shows a thick cortex with thin outer layer, sparse cell layer, and thick inner band of gray matter. Primitive sylvian fissures and very shallow sulci are present. (Right) Axial TlWI MR shows a similar appearance to the previous

image in another

child

I 1 41

MICROCEPHALY

::> .:£ (fJ Cl. Cll

<.l

(fJ

Midline Anomaly

C

•.. III

al

"'C C III

(Left) Sagittal T2WI MR in an infant with severe microcephaly shows absence of the corpus callosum, cortex crossing the midline ~ fused deep gray structures and a large dorsal cyst There is also a single central incisor ~.

(RighI) Axial T2WI MR again shows the large dorsal cyst There is a monovenUicle gray matter crossing the midline [;> and a primitive fused hippocampus ~

=

(Left) Sagittal T I WI MR shows mildly hypoplastic vermis with prominent surrounding CSF. The fasligial recess, primary fissure, and vermian lobu/aUon are present (RighI) Sagittal T2WI MR shows upward rotation of severely hypoplastic vermis in an infant with callosal agenesis, microcephaly, and only primitive sulcalion Fastigiaf crease and primary fissure are seen. Vermian lobulation is simplified. The mesencephalon is "angled" but not "Z4shaped".

=.

(Left) Sagittal T1WI MR shows a very thin corpus callosum SlI in this microcephalic infant (RighI) Axial T2WI MR shows corresponding severe hypomyelination.

I 1 42

Midline Anomaly

MICROCEPHALY OJ

::::l

C.

OJ ....• Microlissencephaly

OJ

(Left) Sagittal T2WI MR shows a "Z-shaped"

brainslem and severe cerebellar hypoplasia. There is open inferior 4th ventricle microcephaly, callosal agenesis, and a smooth cortical surface. (Right) Axial T2WI MR shows a complete lack of cerebral gyral formation

Aicardi-Goutieres

::::l Ul

<>

OJ -0

Ul

c '"

in the same child.

Aicardi-Goutieres (Left) Axial N[CT in this infant shows TORClI-like calcifications

within the basal

ganglia. (Right) Axial T2WI MR shows hypomyelination and severe atrophy in the same patient.

Calcifications

SI are

relatively occult on MR in this child.

(Left) Axial T1WI MR shows volume loss, hypomyelination, and hazy increased signal intensity of the basal ganglia 8l representing

calcification.

(Right) Coronal T2WI MR

shows volume loss and hypomyelination in the same child. These findings became more apparent with serial imaging.

I 1 43

SECTION 2

Meninges Anatomically Based Differentials Dural Calcification(s) Dural-based Mass, Solitary Dural-based Masses, Multiple Falx Lesions

1-2-2 1-2-4 1-2-8

1-2-12

Generic Imaging Patterns Thick Dural Arachnoid, Pial Enhancement Dural Tail Sign

Generalized

1-2-14 1-2-16 1-2-20

DURAL CALCIFICATlON(S)

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DIFFERENTIAL DIAGNOSIS Common • Physiologic Calcification, Dura • Osseous Metaplasia (Falx Contains Fatty Marrow) • Meningioma • Subdural Hematoma, Chronic Less Common • Basal Cell Nevus Syndrome • Benign Nonmeningothelial • Hyperparathyroidism • Hemodialysis • Meningitis

Tumors

Rare but Important • Pseudohypoparathyroidism • Familial Tumoral Calcinosis (Hypo- or Hyperphosphatemic)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Physiologic calcification of the dura common incidental finding on NECT Helpful Clues for Common Diagnoses • Physiologic Calcification, Dura a Common in the middle-age and elderly, falx or tentorium • Osseous Metaplasia (Falx Contains Fatty Marrow) a Incorrectly labeled "dense calcification" on NECT

ot be confused with true falx lipoma on TlWI • Meningioma a Calcified (20-25%): Diffuse, focal, sand-like, sunburst, globular, rim • Subdural Hematoma, Chronic a Inner membrane calcification (in 0.3-2.7%) termed "Matrioska head" or "armored brain" a

Helpful Clues for Less Common Diagnoses • Basal Cell Nevus Syndrome a Multiple jaw cysts (odontogenic keratocysts in 80-90%), mandible> maxilla, rib anomalies a Calcification of falx (eventually 100%), tentorium, peri-clinoid ligaments, dural, choroid plexus & basal ganglia • Benign Nonmeningothelial Tumors a NECT best diagnostic tool a Osteoma most common: Round dense lesion of the inner or outer table (outer table more common), no enhancement, no diploic involvement a Chondroma, osteochondroma less common • Hyperparathyroidism a Dural calcification, osteopenia and osteosclerosis of skull giving "salt and pepper" appearance • Hemodialysis a Long term hemodialysis, associated secondary/tertiary hyperparathyroidism a Calcifications falx, tentorium common Osseous

Physiologic

Calcification,

Dura

Metaplasia (Falx Contains Marrow)

Fatty

I 2 2

Axial bone CT shows physiologic calcification of the falx.

Axial NEeT shows thick calvarium and very prominent, thick ossification along the falx

=.

en

DURAL CALCIFICATlON(S)

c: "" ll.l

~

Osseous Metaplasia (Falx Contains Fatty Marrow)

a. OJ ....

Meningioma

III

(LeFt) Sagiltal T1 WI MR shows high signal Irom fat-containing osseous metaplasia along the lalx cerebri Cl:I. (Right) Axial bone CT shows marked hyperostosis and calcification in this plaque-like meningioma Cl:I along the lelt inner table 01 the skull.

Subdural Hematoma, Chronic

~

Basal Cell Nevus Syndrome (Left) Axial bone CT demonstrates bilateral chronic subdural collections with dense calcification along the inner membranes. Shunt tubes are noted in the lateral ventricles. (Right) Axial NECT demonstrates extensive dural calcification primarily involving the (alx cerebri and tentorium cere belli 9- in a patient with basal cell nevus syndrome and multiple jaw cysts.

(Left) Axial NECT demonstrates a rare, lobulated, calcified, chondroma

arising from the

lelt Iron tal dura Cl:I. (Rigl1t) Axial NECT shows densely calcilied dura, especially prominent along the tentorium

=.

Faint

calcification in the basal ganglia SI is seen.

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DURAL-BASED MASS, SOLITARY

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Common • Epidural Hematoma • Meningioma • Metastases, Meningeal • Neurosarcoid • Lymphoma, Metastatic, Intracranial • Empyema less Common • Tuberculosis • Meningioma, Atypical and Malignant • Benign Nonmeningothelial Tumors • Malignant Nonmeningothelial Tumors • Langerhans Cell Histiocytosis • Plasmacytoma • Neuroblastoma, Metastatic • Leukemia Rare but Important • Pseudotumor, Intracranial • Hypertrophic Pachymeningitis • Extramedullary Hematopoiesis • Rosai-Dorfman Disease • Neurocutaneous Melanosis (Melanocytoma/Mela noma) • Fibro-Osseous Lesion (Calcifying Pseudo neoplasm)

•

•

•

•

ESSENTIAL INFORMATION

•

I 2 4

Does not cross sutures unless sutural diastasis/fracture present, can cross falx & tentorium o Trauma history, calvarial fracture in 85-95% Meningioma o Hyperostosis, cortical irregularity, calcification, peritumoral edema, trapped CSF clefts common o Best imaging tool: MR + contrast 095% enhance homogeneously & intensely, dural tail often present o MRS: Elevated alanine Metastases, Meningeal o Multiple> solitary lesions o Skull often but not always infiltrated o Often known extracranial primary neoplasm Neurosarcoid o 5% present as solitary dural-based extra-axial mass o Presence of associated leptomeningeal enhancement additional clue o Abnormal CXR, labs (increase ESR, ACE levels) Lymphoma, Metastatic, Intracranial o Localized dural mass mimicking meningioma o 10-30% of patients with systemic lymphoma may develop secondary CNS involvement o Leptomeningeal, parenchymal involvement more common Empyema o Extra-axial fluid collection with rim-enhancement & restricted diffusion o Look for paranasal sinus or mastoid disease o

DIFFERENTIAL DIAGNOSIS

Helpful Clues for less Common Diagnoses • Tuberculosis o Giant tuberculoma may mimic meningioma o Abnormal CXR, lab values o Travel history to endemic areas, immunocompromised o MRS: Elevated lipid/lactate • Meningioma, Atypical and Malignant o Dural-based lesion locally invasive with areas of necrosis & marked brain edema o Indistinct tumor margins, may extend into brain, skull, scalp o Biopsy is essential

DURAL-BASED • Benign Nonmeningothelial Tumors (}Lesions of dura, skull, skull base, NECT best diagnostic tool (}Chondroma: Expansile, lobulated, curvilinear matrix calcification, mild enhancement (}Osteochondroma: Stalk is contiguous with the parent bone intramedullary marrow, may see calcified matrix in cap atop cortical bone (}Osteoma: Round dense lesion of the inner or outer table (outer table more common), no enhancement, no diploic involvement • Malignant Nonmeningothelial Tumors (}Highly aggressive dural, skull, scalp lesions invading locally (}Biopsy is essential • Langerhans Cell Histiocytosis (}Well-defined lytic skull lesion, beveled edge, associated dural & scalp soft tissue (}Younger age group • Plasmacytoma (}Solitary dural mass in patient with multiple myeloma, mimics meningioma (}Skeletal survey may help • Neuroblastoma, Metastatic (}Age < 5, known extracranial disease, calvarial-based mass, often around orbit/sphenoid wings (}NECT: "Hair-on-end" spiculated periostitis • Leukemia (}May present with or mimic hematoma

MASS, SOLITARY (}Homogeneously enhancing extra-axial tumor(s) in patient with known or suspected myeloproliferative disorder Helpful Clues for Rare Diagnoses

• Pseudotumor, Intracranial (}Enhancing, infiltrating meningeal mass (}Predilection for meninges of cavernous sinus area or basal meninges (}Intracranial involvement in absence of orbital disease is rule (> 90%) • Extramedullary Hematopoiesis (}Patients with chronic anemia or marrow depletion (}Multiple> solitary (}Lobulated, homogeneous (}Mimics subdural hematoma on NECT (}Strong homogeneous enhancement • Rosai-Dorfman Disease (}Sinus histiocytosis with massive lymphadenopathy (}Multiple> solitary (}Mimics meningiomatosis, sarcoid, extramedullary hematopoiesis

SELECTED 1.

2.

3.

REFERENCES

Sahin F et al: Dural plasmacytoma mimicking meningioma in a patient with multiple myeloma. J Clin Neurosci. 13(2):259-61, 2006 Richiello A et al: Dural metastasis mimicking falx meningioma. Case report.J eurosurg Sci. 47(3):167-71; discussion 171, 2003 Goldsher 0 et al: Dural "tail" associated with meningiomas on Gd-DTPA-enhanced MR images: characteristics, differential diagnostic value, and possible implications for treatment. Radiology. 176(2):447-50, 1990

Epidural Hematoma

=

Axial NEeT shows a classic biconvex hyperdense mass in the left middle cranial fossa typical for epidural hematoma Left (rontal contusions are a/so present

Coronal T1 C+ M R shows a densely, homogeneously enhancing dural-based mass with faim "sunburst" pattern ~ Note the U,ill dural tail associated with the

8'1.

massl!:lD.

=.

I 2 5

DURAL-BASED

(f)

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al

(Left) Axial T I WI MR shows

"0

a renal cell carcinoma

c C1l

=

metastasis involving the calvarium with associated scalp and dural-based mass. (Right) Axial T7 C+ MR shows a neurosarcoid with linear and nodular coating of the medulla, pons, and midbrain and focal dural-based mass along the tentorium B.

=

(Left) Coronal T7 C+ MR shows a dural-based enhancing mass in the region of the cisterna magna in a patient with systemic lymphoma. Note prominent "dural tails" PJ:!:l. (Right) Coronal TIWI MR show "en plaque" focal dural thickening SiI that can mimic meningioma. Notice the faint ependymal

=

enhancement around the temporal horn ~ ependymitis.

indicating

(Leh) Coronal T7 C+ MR shows enhancing mass mushrooming inwards (deforming underlying brain) as well as outwards into the scalp PJ:!:l with displacement/invasion of superior sagillal sinus ~. (Right) Axial bone CT demonstrates a large expansile hyperde/lSe lesion with a chondroid matrix arising from the left occipital bone. Ilistologically proven chondrobfastoma.

.=

/I

/I

=

I 2 6

MASS, SOLITARY

DURAL-BASED

MASS, SOLITARY

(f)

" C

Neuroblastoma,

Metastatic (Left) Axial CECT shows

heterogeneous

enhancement

of a primary meningeal sarcoma with a dura/-based mass skull destruction, and scalp infi/tralion 8:11. (Rigl1t) Coronal T7 C+ MR

s: CI>

:J :J co CI> CJ>

demonstrates an intensely enhancing diploic space/scalp metaSlasis with displacement of the superior sagillal sinus by the epidural tumor EillI.

=

leukemia (Left) Axial CECT

demonstrates homogeneously enhancing extra·axial dura/-based masses in patient with systemic leukemia. Note poorly defined margins, brain infiltration

[;>J

with

edema. (Rigl1t) Coronal Tl C+ FS MR shows mass in lefl cavernous sinus in a patient with infiltrating intracranial pseudolumor.

=

Dural "taW' P.:tJ along middle fossa (foor a/50 represents pseudOlumor.

(Left) Coronal T7 C+ MR shows a solitary dural-based mass in a patient with

=

striking spinal extramedullary hematopoiesis. This was the only intracranial lesion. (Right) Axial Tl C+ MR shows dural-based, strongly

enhancing masses in this patient with known sinus histiocytosis with massive lymphadenopathy.

I 2 7

DURAL-BASED MASSES, MULTIPLE

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DIFFERENTIAL DIAGNOSIS

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Common • Meningioma (Multiple Meningiomatosis) • Metastases, Meningeal • Subdural Hematomas, Chronic Less Common • Neurosarcoid • Neurofibromatosis Type 2 • Lymphoma, Metastatic, Intracranial Rare but Important • Extramedullary Hematopoiesis • Langerhans Cell Histiocytosis • Erdheim-Chester Disease • Rosai-Dorfman Disease • Epidural Hematoma • Myeloma • Leukemia • Tuberculosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • > 95% multiple dural-based masses are either meningiomas or metastases Helpful Clues for Common Diagnoses • Meningioma (Multiple Meningiomatosis) o 1-9% of imaged meningioma cases o Most occur in women o Can occur in absence of NF2 o MRS: Characteristic alanine peak • Metastases, Meningeal o Skull often but not always infiltrated o Multifocal > solitary lesions o NECT, bone algorithm, for osseous evaluation o MR C+ if dural, scalp involved o Often known extracranial primary neoplasm • Prostate, breast, neuroblastoma • Subdural Hematomas, Chronic o Remote trauma history o NECT • Varying density • Fluid-fluid levels • Less common: Calcification of inner membranes o

I 2 8

MR

• T1 C+ thick, enhancing, membranes

dural

• ± Foci of old hemorrhage

Helpful Clues for Less Common Diagnoses • Neurosarcoid o Multifocal, dural-based foci o Presence of associated leptomeningeal enhancement additional clue o Other findings • Abnormal CXR • Increased erythrocyte sedimentation rate (ESR) & serum angiotensin converting enzyme (ACE) • Neurofibromatosis Type 2 o Multiple inherited schwannomas, meningiomas, & ependymomas o Best diagnostic clue: Bilateral vestibular schwannomas o Schwannomas on cranial nerves and spinal nerve roots o Only 10% of patients with multiple meningiomas have F2 • Lymphoma, Metastatic, Intracranial o Multiple or solitary dural mass mimicking meningioma o 10-30% of patients with systemic lymphoma may develop secondary CNS involvement • Parenchymal> dural involvement Helpful Clues for Rare Diagnoses • Extramedullary Hematopoiesis o Found in patients with chronic anemias or marrow depletion o Smooth homogeneous dural-based masses o Mimics subdural hematoma on NECT o Isointense with brain on T1 WI, hypointense on T2WI o Enhances strongly, homogeneously o May show osseous findings of underlying disease o Confirm with Tc-99m-sulfur colloid scan • Langerhans Cell Histiocytosis o Well-defined lytic skull lesion with "beveled edges" o Associated dural & scalp soft tissue masses common o Patients often present with diabetes insipidus • Thick, enhancing infundibulum • Absent posterior pituitary bright spot • Erdheim-Chester Disease o Non-Langerhans type histiocytosis

DURAL-BASED

MASSES, MULTIPLE

(/)

" c:

Affects multiple organs (including long bones, skin, lung, soft tissue) o Histiocytic infiltration of long bone metaphyses • Manifests as sclerotic appearance on conventional radiographs o Dural mass lesions most common • Falx cerebri, tentorium, sella/parasellar regions • Biopsy essential for diagnosis o May involve brain parenchyma • Rosai-Dorfman Disease o Sinus histiocytosis with massive lymphadenopathy o Propensity to arise from the base of the skull, para sellar region, orbit o May resemble multiple meningiomatosis, sarcoid o CNS Rosai-Dorfman disease has definite male predominance o Dural-based, extra-axial enhancing masses most common finding o May infiltrate brain with striking perilesional cerebral edema o Biopsy essential for diagnosis • Epidural Hematoma o Trauma history o < 5% multiple/bilateral o NECT (acute phase) • Hyperdense biconvex extra-axial mass • 90-95% associated skull fracture o Does not cross sutures • May if sutural diastasis/fracture present o Can cross falx & tentorium

o

o

Meningioma (Multiple Meningiomatosis)

± Underlying contusions

of brain

parenchyma • Myeloma o Dural-based masses with lytic skull lesions o Skeletal survey may be helpful • Leukemia o May present with or mimic hematoma o Homogeneously enhancing extra-axial tumor(s) in patient with known or suspected myeloproliferative disorder • Tuberculosis o Marked meningeal enhancement, with basilar predominance, parenchymal tuberculomas, pachymeningeal involvement with dural thickening, enhancement (may mimic meningioma) o Abnormal CXR & lab values o Travel history to endemic areas, immunocompromised

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SELECTED REFERENCES 1.

2.

3.

4.

5.

Sundaram C et al: Isolated Rosai Dorfman disease of the central nervous system presenting as dural-based and intraparenchymallesions. Clin europathol. 24(3):112-7, 2005 Ahn JY et al: Meningeal chloroma (granulocytic sarcoma) in acute lymphoblastic leukemia mimicking a falx meningioma. J Neurooncol. 60(1):31-5, 2002 BendsZlls M et al: Diagnosing dural metastases: the value of HI magnetic resonance spectroscopy. Neuroradiology. 43(4):285-9,2001 Goyal M el al: Imaging appearance of pachymeningeal tuberculosis. AJR Am J Roentgenol. 169(5):1421-4, 1997 Wilson JD et al: Mill features of intracranial sarcoidosis mimicking meningiomas. Clin Imaging. ]8(3):184-8, 1994

Metastases, Meningeal

I Axial TI C+ MR shows multiple, lobulaled, strongly--enhancin{5; dural-based masses characteristic lor multiple meningiomalosis syndrome. The patienl had no evidence for NF2.

Coronal TI C + M R shows dural thickening and multiple dural-based melastasis ~. Notice the infiltraled inhomogeneously hypointense skull 81.

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MASSES,

MULTIPLE

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Subdural Hematomas,

III

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Chronic

(Left) Coronal T1 C+ MR shows a lelt parieta/l:ll and a very small right parietal chronic subdural hematoma ~ Both contain old blood. Note extensive dural

thickening and enhancement 1:]. (RighI) Axial T7 C+ MR shows marked enhancement 01 multi(ocal dural-based

neurosarcoid

=.

(Lefl) Axial T7 C+ MR shows extensive meningiomalOsis/ in the posterior fossa

=.

schwannoma

in the left

lAC-CPA SI and a tiny one at the (undus 01 the right lAC I:ll. (RighI) Axial T I C+ MR demonstrates multiple dural-based enhancing masses I:';] in the region of the cisterna magna and lelt CPA in a patient with systemic B cell lymphoma.

Extramedullary Hematopoiesis (Left) Axial T7 C+ MR shows multiple, enhancing, dural-based lesions along lalx cerebr; m. I esions were very hypointense on T2WI. (Rig"') Axial CECT shows multiple, destructive, osseous, and dura/-based

=

masses.

I 2 10

Langerhans Cell Histiocytosis

DURAL-BASED

Erdheim-Chester

Disease

MASSES,

MULTIPLE

Rosai-Dorfman

Disease

CIl

c: "

(Left) Axial T I C+ MR shows mulliple enhancing foci in the brain parenchyma and cavernous sinus/orbital apex B in a patient with non-Langerhans histiocytosis. (Righi) Coronal T1 C+ MR shows multiple, dural-based, strongly enhancing masses in a patient with known sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease).

=::I

Epidural Hematoma

Myeloma (Lefl) Axial NECT shows bilateral epidural hematomas PJ:i:l. Note rapid bleeding with ffuid-ffuid levels 2>. Bilateral epidural hematomas are uncommon (in contrast to subdural hematomas). (Righi) Axial NEeT shows mulliple deSlruclive skull and dural-based hyperdense masses II] in a patient with known myeloma.

(Left) Axial CECT shows large bilaleral convexity leukemic dural masses =::I. The outer and inner

calvarium HI appears spiculated due to the extensive marrow involvement.

(Right)

Coronal

T1 WI MR shows nodular "en plaque" dural thickening along bOlh sides of tentorium. Notice faint ependymal enhancement around the temporal horn -7 indica ling ependymilis.

=::I

I 2 11

FALX lESIONS

(f)

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• Osseous Metaplasia o Different from simple "dense dural calcification" on NECT o Look for cortex and medullary space (bone

DIFFERENTIAL DIAGNOSIS Common • Physiologic Calcification, Dura • Osseous Metaplasia • Subdural Hematoma, Acute • Meningioma • Metastases, Meningeal

CT)

Most common in anterior/mid-falx Mottled hyperintensity (1'1WI) surrounded by hypointense dense cortex (T2WI) o "Blooms" on GRE o True falx lipoma rare (look for chemical shift artifact) • Subdural Hematoma, Acute o Can be isolated; may extend along convexities, tentorium o Look for signs of nonaccidental trauma (shaking) in children with interhemispheric SDH • Meningioma o Common location for meningiomas o Most arise along middle 1/3rd of the superior sagittal sinus (SSS) o May grow into, occlude SSS o Look for "dural tail" sign • Metastases, Meningeal o Can mimic meningiomas o o

less Common • Neurosarcoid • Extra-Axial Empyema Rare but Important • Intracranial Hypotension • Hypertrophic Pachymeningitis • Erdheim-Chester Disease • Rosai-Dorfman Disease • Extramedullary Hematopoiesis • Chondrosarcoma • Solitary Fibrous Tumor • Hemangiopericytoma • Dural A-V Fistula

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Smooth dural thickening, enhancement usually benign • "Lumpy-bumpy" not always malignant! Helpful Clues for Common Diagnoses • Physiologic Calcification, Dura o Common in the middle-aged/elderly, or tentorium o Dense amorphous Ca++ plaques

Osseous

I 2 12

Metaplasia

Sagittal T1WI MR shows high signal from fat-containing osseous metaplasia along the falx cerebri 1:]. Also note chronically thrombosed, superior sagittal and straight sjnuse5~.

falx

Helpful Clues for less Common Diagnoses • Neurosarcoid o Nodular, "lumpy-bumpy" falx • Extra-Axial Empyema o Frontal sinusitis - empyema ± posterior extension along falx o Rim-enhancement, restricts on DWI

Subdural

Hematoma,

Acute

Axial NECT shows acute subdural hemorrhage, with a farger, parafalcine, interhemispheric component HJ and a smaller convexity component

=.

FALX LESIONS

Neurosarcoid (Left) Coronal TI C+ MR shows strongly enhancing mass attached to lalx. (Right) Axial T1WI MR shows "lumpy-bumpy" enhancement along the lalx and frontal dura in a patient with neurosarcoid

=.

Extramedullary

Hematopoiesis (Left) Axial TI C+ FS MR shows a classic multiloculated paralalcine subdural empyema 1:1'2 with rim enhancement (Right) Axial T2WI MR shows multiple, lobulated, dural-based masses ~ along the falx. Lesions are much more hypoinlenS€

than

typical meningiomas.

Dural A-V Fistula (Lelt) Lateral angiography in the early venous phase, shows a very hypervascular faJcine mass ~ with multiple veins

prominent

draining

The pre-operative

diagnosis was meningioma. HPC was lound at surgery. (Right) Lateral angiography shows a large posterior meningeal artery ~ prominent parafalcine vessels occluded SSS Acutely thrombosed dAvr mimicked brain tumor on MR. (Courtesy P Skejo, MOJ.

I 2 13

THICK DURA/ARACHNOID,

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DIFFERENTIAL DIAGNOSIS Common • Dural Thickening, Post-Operative • Metastases, Meningeal • Subdural Hematoma, Chronic • Meningitis • Intracranial Hypotension Less Common • Neurosarcoid • Lymphoma, Metastatic, Intracranial • Hypertrophic Pachymeningitis • Meningioma Rare but Important • Pseudotumor, Intracranial • Extramedullary Hematopoiesis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Dura is a thick dense fibrocollagenous sheet that is attached to skull at sutures • Arachnoid is a thin layer, loosely attached to the dura & contains arachnoid villi Helpful Clues for Common Diagnoses • Dural Thickening, Post-Operative o Post-operative dural enhancement may appear within hours, last months/years • Metastases, Meningeal o Smooth or nodular enhancement; usually accompanied by adjacent skull lesions • Subdural Hematoma, Chronic o Smooth dural enhancement

Dural Thickening,

Post-Operative

o MR sequences reveal blood products (GRE) • Meningitis o Dura/arachnoid pattern in meningitis less common than pia/subarachnoid • Intracranial Hypotension o Diffuse dural enhancement typical o "Slumping midbrain", low tonsils & subdural effusions/hematomas

Helpful Clues for Less Common Diagnoses • Neurosarcoid o Dural thickening & enhancement o Predilection for basal cisterns • Lymphoma, Metastatic, Intracranial o Usually diffuse, multifocal with underlying bone involvement o May selectively affect meninges • Hypertrophic Pachymeningitis o Diffuse dural thickening & enhancement o Idiopathic; etiology often undetermined even with biopsy • Meningioma o Focal or diffuse dural enhancement o May see adjacent bone changes o Multiple associated with F2 Helpful Clues for Rare Diagnoses • Pseudotumor, Intracranial o Enhancing, infiltrative meningeal mass o Predilection for cavernous sinus region & basal meninges • Extramedullary Hematopoiesis o Homogeneous enhancement in patients with chronic anemias or marrow depletion

Metastases,

Meningeal

I 2 14

Coronal T1 c+ MR shows smoolh durallhickening ~ & enhancement after a left parietal craniotomy. Posl-operaUve dural enhancement is usually diffuse 8, may lasl for years afler the procedure.

Axial T1 C+ MR shows diffuse enhancement

=

related

to metastatic disease. Metastatic disease is typically nodular 8, associated wilh adjacenl bone changes. Disease may be focal or diffuse.

THICK DURA/ARACHNOID,

Subdural Hematoma,

GENERALIZED

Chronic (Left) Coronal T1 C+ MR shows diffuse dural enhancement related to a chronic subdural hematoma E2. Hematomas show

=

I'b/ooming"

CRE

artifact on

sequences & may become calcified. (Right) Axial T1 C+ MR shows diffuse dural enhancement II] in this meningitis patient Leptomeningeal enhancement is much more

common than pachymeningeal enhancement

(dural)

in meningitis.

Meningitis remains a clinical-laboratory diagnosis.

Neurosarcoid (Left) Coronal T1 C+ FS MR shows smooth dural thickening & enhancement r=l in this patient with chronic headaches. Sagittal images (not shown) revealed a 'I slumping" midbrain typical of intracranial hypotension. (Right) Axial T1 C+ FS MR shows both smooth dural enhancement SI & leptomeningeal enhancement in this neurosarcoid

patient.

Dural

disease is common in neurosarcoid. There is a basilar predominance of the meningeal disease.

(Left) Axial T1 C+ MR shows diffuse dural thickening & enhancement classic for hypertrophic pachymeningitis. Idiopathic

=

pachymeningitis

can mimic

neoplasm

or aggressive

infection.

The enhancement

may be smooth or nodular. (Right) Coronal T1 C+ MR shows multiple extra-axial, dural-based masses due to meningiomas ~ in this patient with type 2 neurofibromatosis.

Bilateral

vestibular schwannomas also present.

are

I 2 15

en

PIAL ENHANCEMENT

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DIFFERENTIAL DIAGNOSIS Common • Meningitis • Metastases, Meningeal • Cerebral Infarction, Subacute • Neurosarcoid Less Common • Vasculitis • Glioblastoma Multiforme • Sturge-Weber Syndrome • Moyamoya Rare but Important • Wegener Granulomatosis, Brain • Lyme Disease • Dural A-V Fistula • Meningioangiomatosis • eurocutaneous Melanosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Pia is innermost layer of leptomeninges which covers brain & invaginates into sulci • Enhancement is typically related to infectious/inflammatory, vascular or neoplastic processes • Differentiate infectious & noninfectious processes to narrow differential

I 2 16

Helpful Clues for Common Diagnoses • Meningitis o Typical signs & symptoms of infection: Fever, neck stiffness, increased WBC o Can be divided into pyogenic, lymphocytic & chronic meningitis o TB, fungal meningitis often basilar & confluent o FLAIR MR: Sulcal hyperintensity o Normal enhanced brain MR does not exclude meningitis (clinical diagnosis) • Metastases, Meningeal o Nodular or mass-like leptomeningeal enhancement typical o Common primary tumors include breast, lung, melanoma & lymphoma o Primary tumor often known • Cerebral Infarction, Subacute o May see enhancement in late acute or early subacute infarct

Gyriform enhancement in a vascular territory typical • Associated with wedged-shaped area of T2/FLAIR hyperintensity • Neurosarcoid o Pial enhancement often associated with dural mass(es) • Predilection for basal cisterns o Parenchymal disease & leptomeningeal disease (approximately 1/3 each) o Facial nerve palsy & other cranial neuropathies common o Review CXR to look for bilateral symmetrical hilar lymphadenopathy o

Helpful Clues for Less Common Diagnoses • Vasculitis o Heterogeneous group of CNS disorders characterized by nonatheromatous inflammation & necrosis of vessel walls o In addition to pial enhancement, may see T2 hyperintensities, hemorrhage &/or restricted diffusion o DSA/CTA: Alternating stenosis & dilatation primarily 2nd & 3rd order branches • Glioblastoma Multiforme o May cause focal or diffuse pial enhancement in addition to primary enhancing mass • Related to primary extension of tumor or metastases • Sturge-Weber Syndrome o Enhancement related to pial angiomatosis: Unilateral 80%, bilateral 20% o Cortical Ca++, atrophy, & enlarged ipsilateral choroid plexus o Occipital, parietal & frontal/temporal lobes • Moyamoya o Idiopathic progressive arteriopathy of childhood o Progressive narrowing of distal ICA & proximal circle of Willis vessels with secondary collateralization o Cloud-like lenticulostriate & thalamostriate collaterals on angiography o Lenticulostriate collaterals: Enhancing "dots" in basal ganglia & "net-like" thin vessels in basal cisterns o FLAIR: "Ivy sign": Slow-flowing engorged pial vessels, thickened arachnoid o Leptomeningeal enhancement (contrast-enhanced "ivy sign")

PIAL ENHANCEMENT Helpful Clues for Rare Diagnoses • Wegener Granulomatosis, Brain o Nonneoplastic, aseptic, necrotizing vasculitis that preferentially involves upper & lower respiratory tracts & kidneys o Soft tissue mass in nose with septal & non-septal bone destruction o May extend into orbits & intracranially, affecting meninges • Lyme Disease o Multisystem inflammatory disorder may present as meningitis, encephalitis &/or vasculitis o Lesions simulate multiple sclerosis in a patient with skin rash & flu-like illness o T2 hyperintensity in periventricular white matter o Meningeal enhancement & CN? enhancement common • Dural A-V Fistula o Network of tiny vessels in wall of thrombosed dural venous sinus o Look for flow voids of collateral vessels o Diffuse dural enhancement is rare • Meningioangiomatosis o Rare o Hamartomatous cortical/leptomeningeal malformation o Cortical mass with Ca++ & enhancement o Can infiltrate parenchyma via perivascular spaces o Enhancement pattern: Linear, granular or gyriform

Neurofibromatosis found in 50% of patients (particularly NF2) • Neurocutaneous Melanosis o Congenital phakomatosis characterized by giant or multiple cutaneous melanocytic nevi & benign & malignant CNS melanotic lesions o Foci of T1 hyperintensity (parenchymal melanosis) in amygdala or cerebellum o Diffuse leptomeningeal enhancement o Hydrocephalus common o

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Alternative Differential Approaches • Infectious/inflammatory lesions: Meningitis, neurosarcoid, Lyme disease • Vascular lesions: Cerebral infarction, vasculitis, Sturge-Weber syndrome, Moyamoya disease, Wegener granulomatosis, dural A-V fistula • Neoplastic lesions: Metastases, glioblastoma multiforme

SELECTED REFERENCES 1.

2. 3.

Chu

we

et al:

eurocutaneous

melanomatosis

with a

rapidly deteriorating course. AJ RAm J Neuroradiol. 24(2):287-90,2003 Byrd SE Cl al: MR imaging of symptomatic neurocutaneous melanosis in children. Pediatr Radiol. 27(1):39-44, 1997 Aizpuru RN et al: Meningioangiomatosis: clinical, radiologic, and histopathologic correlation. Radiology. 179(3):819-21, 1991

Metastases,

Meningeal

I Coronal T1 c+ MR shows diffuse leptomeningeal enhancement It] in this patient with TB meningitis. T8 & fungal meningitides are often basilar & confluent.

Axial T1 C+ FS MR shows abnormal enhancement along the optic nerves ICR left temporal & occipital cerebral sulci It] in a breast cancer patient. Meningeal melastases may be smooth or nodular.

2 17

PIAL ENHANCEMENT

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(Left) Corona/ TI C+ MR shows diffuse leptomeningeal carcinomatosis with extensive enhancement. Meningeal metastases can mimic other meningeal processes including meningitis & neurosarcoid. (Right) Axial TI C+ MR shows leptomeningeal enhancement in the left occipita/lobe related to a

=

=

subacute posterior cerebral artery infarct. There was corresponding T2/FLAIR hyperintensity in the same vascular distribution.

Vasculitis (Left) Axial TI C+ MR shows finear & nodular enhancement !!:ill. Pial enhancement is often associated with dural disease. Patients commonly present with cranial neuropathies. eNS disease is present in 5% of

neurosarcoid patients.

=

(Right) Corona/ TI C+ MR shows focal pial & dural enhancement in this vasculitis patient related to TB meningitis. T2 images (not shown) show extensive hyperinlensily in the basal ganglia.

Glioblastoma

I 2 18

(Left) Axial CECT shows extensive pial enhancement related to diffuse CSF seeding of GBM. These malignant tumors often have associated ependymal extension which results in CSF seeding. (Right) Axial TI C+ MR shows extensive bilateral enhancement related lO pial angiomatosis. This is typically unilateral (BO%), & the occipita/lobe is most commonly involved. Angiomatosis is a congenital malformalion in which fetal cortical veins faillo develop normally.

Multiforme

Sturge-Weber

Syndrome

PIAL ENHANCEMENT

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III

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(Left) Axial T1 C+ MR shows punctate enhancement related to lenticulostriate collateral vessels in the basal ganglia & mild diffuse pial enhancement related to slow-flOIY in engorged pial vessels & thick arachnoid. The collaterals give the angiographic appearance of "pufr of smoke", moyamoya in Japanese. (RighI) Coronal T1 C+ MR shows pial enhancement I!:J2 & basal ganglia enhancement due to formation of collaterals in moyamoya

=

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=

disease.

(Left) Coronal T1 C+ MR shows enhancing CN] & CNS bilaterally within Meckel cave 811. CN7 was also involved in this Lyme

=

disease patient.

Imaging

often mimics multiple sclerosis with perivenlricular while maller lesions & enhancement. (Right) Axial T1 C+ FS MR shows enhancement

in the left

internal auditory canal-= involving CN 7 related to Lyme disease. Meningeal enhancement & involvement of the facial nerve is common.

Meningioangiomatosis

Neurocutaneous

Melanosis (Left) Axial T1 C+ MR shows focal serpentine cortical/pial enhancement in this

patient

with

=

meningioangiomalosis. This lesion is a hamartomatous malformation. CT showed calcification of the lesion. (Right) Axial T1 C+ MR show the entire surface of the brain and adjacent subarachnoid space enhance intensely related to pial melanosis.

Note

hydrocephalus caused by reduced absorption of through the arachnoid villi.

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I 2 19

DURAL TAIL SIGN

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DIFFERENTIAL DIAGNOSIS Common • Meningioma • Metastases, Meningeal

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Less Common • Neurosarcoid • Lymphoma, Metastatic, Intracranial • Tuberculosis Rare but Important • Histiocytosis • Meningioma, Atypical and Malignant • Erdheim-Chester Disease • Leukemia • Lymphocytic Hypophysitis • Pituitary Macroadenoma • Hemangioma, Calvarial • Schwan noma • Rosai-Dorfman Disease

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • "Dural taiJ" actually a 3D "collar" around dural-based lesion • Benign reactive dural thickening> neoplastic invasion • Suggestive of meningioma but not pathognomonic • Look for scalp, skull lesions • Clinical history, laboratory helpful • Biopsy may be necessary for confirmation

Helpful Clues for Common Diagnoses • Meningioma a 35-80% of intracranial meningiomas associated with dural tail a More common with convexity, falx meningiomas • Less frequently seen in posterior fossa • Least common in spine a Usually reactive change rather than direct neoplastic invasion • Metastases, Meningeal a Adjacent skull often but not always infil trated a Often but not always multifocal a Often known extra cranial primary neoplasm: Prostate, breast, neuroblastoma a Beware: Breast metastasis can mimic meningioma! Helpful Clues for Less Common Diagnoses • Neurosarcoid a Occasionally (5%) presents as solitary, dural-based, extra-axial mass a Presence of associated leptomeningeal enhancement additional clue a Abnormal CXR, lab values (ESR, ACE levels elevated) • Lymphoma, Metastatic, Intracranial a Localized dural mass mimics meningioma a Dural tail probably infiltrative tumor • Tuberculosis a Basilar leptomeningitis common a Dural involvement less common a Focal dural mass may mimic meningioma

Meningioma

Metastases, Meningeal

Axial TI C+ FS MR shows classic convexity meningioma with dural tail sign Note that benign (reactive) dural thickening is slightly more hyperintense than neoplasm itself

Coronal T7WI MR shows calvarial metastasis with associated dural, scalp soft tjssue involvement Notice

I 2 20

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the dural tail

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(Left) Axial T1 C+ MR shows marked enhancement of a multifocal dural-based neurosarcoid with a subtle dural tail ~ along the

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temporal bone. (Right) Coronal T1 C+ MR shows basilar meningitis and tuberculomas in sylvian fissure 81. Note dural thickening along right cavernous sinus

=.

leukemia (Leh) Coronal T1 C+ MR shows a granulocytic sarcoma with intense enhancement &.. Note dural tail [;> enhances even more strongly than the tumor. (Right) SagiLtal T1 C+ FS MR shows lymphocytic hypophysitis =:I enhancing intensely and uniformly, inseparable from the pituitary gland. Note a subtfe "dural tail sign" 81 along basisphenoid.

Pituitary Macroadenoma (Leh) SagiLtal T1 C+ MR shows a classic pituitary macroadenoma with sellar erosion and suprasellar extension Notice a thin dural tail extending inferiorly along the clivus 81. (Right) Coronal T1 C+ MR shows vestibular schwannoma entering lAC =:I. Note the dural tail Elll a rare finding

=.

with schwannomas.

I 2 21

SECTION 3

Ventricles, Periventricular Regions Anatomically Based Differentials Ventricles, Normal Variants Choroid Plexus Lesions Ependymal/Subependymal Lesions Lateral Ventricle Mass Thick Septum Pellucidum Foramen of Monro Mass Third Ventricle Mass, General Third Ventricle Mass, Body/Posterior Cerebral Aqueduct/Periaqueductal Lesion Fourth Ventricle Mass

1-3-2 1-3-6 1-3-8 1-3-12 1-3-16 1-3-18 1-3-22 1-3-26 1-3-28 1-3-32

Generic Imaging Patterns "Bubbly-Appearing" Intraventricular Ependymal Enhancement Large Ventricles Small Ventricles Asymmetric Lateral Ventricles Irregular Lateral Ventricles Periventricular Enhancing Lesions

Modality-Specific

Mass

1-3-36 1-3-40 1-3-44 1-3-48 1-3-50 1-3-54 1-3-58

Imaging Findings

Intraventricular Calcification(s) Periventricular Calcification Periventricular T2/FLAIR Hyperintense Lesions

1-3-62 1-3-66 1-3-72

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DIFFERENTIAL DIAGNOSIS Common • Asymmetric Lateral Ventricles (ALV) • Intraventricular CSF Pulsation Artifact (Flow-Related) • Cavum Septi Pellucidi (CSP) ± Cavum Vergae • Coarctation of Anterior Horns Less Common • Connatal Cysts • Germinolytic Cysts Rare but Important • Open Inferior 4th Ventricle (Blake Pouch Remnant)

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ESSENTIAL INFORMATION Key Differential Diagnosis Issues • ormal variants are asymptomatic • Frequency varies with site o Lateral ventricle variants common o Fourth ventricle less common o Third ventricle variants (such as thick floor) uncommon (rare at imaging) but important for endoscopic third ventriculostomy • Clinical history key! o Headaches o Papilledema o History of prior trauma, infection

I 3 2

Helpful Clues for Common Diagnoses • Asymmetric Lateral Ventricles (ALV) o Leaflet of septum pellucidum ± "pushed" to smaller ventricle side o ALV + normal hemisphere • Usually normal variant • Exclude obstruction at foramen of Monro • Cyst or web • Tumor (e.g., choroid plexus neoplasm) o ALV+ abnormal hemisphere • Larger hemisphere: Hemimegalencephaly (ipsilateral ventricle large, often deformed) • Smaller hemisphere: Unilateral atrophy or porencephaly o ALV = sign of functioning shunt if shunt in smaller ventricle o Helpful techniques in evaluating ventricles, possible obstruction

• • • •

Sagittal, coronal thin-section T2WI High resolution FIESTA CSF flow study Intraventricular contrast outlines obstruction • Intravenous contrast (helpful in detecting small lesions) • Intraventricular CSF Pulsation Artifact (Flow-Related) o Most common on high field MR • FLAIRsequence most commonly affected • Look at another sequence or another plane (artifact disappears) • Typically occur in phase-encoding axis • Look for phase artifact propagating across image • When in doubt, change phase-encoding direction and repeat sequence • Cavum Septi Pellucidi (CSP) ± Cavum Vergae o Developing ventricle closes from posterior - anterior • Therefore cavum vergae (CV) does not occur in isolation • CSP can exist ± CV but not reverse o CSP lacks ependymal lining (term "5th ventricle" inaccurate) o CSP leaflets should be parallel • If septal leaflets are not parallel, consider encysted cavum • Look for signs of obstructive hydrocephalus • Look for evidence of prior trauma with epi-GRE or SWI to detect hemorrhagic residua • Coarctation of Anterior Horns o Normal variant o Exclude subependymal pseudocysts seen with inborn errors of metabolism, TORCH, ischemia o Findings helpful in distinguishing coarcted anterior horns from pathologic subependymal pseudocysts • Peroxisomal biogenesis disorder (Zellweger): Cortical dysplasia, hypo myelination, stippled epiphyses, hypotonia • Mitochondrial disorders: MRS lactate doublet

VENTRiClES, NORMAL VARIANTS • TORCH (cytomegalovirus): Look for microcephaly, periventricular calcifications • Hypoxic ischemic insult of newborn: History of perinatal distress! Helpful Clues for less Common Diagnoses • Connatal Cysts o Considered normal variant o May be anterior choroid plexus cysts • Controversial entity • Transient finding • Present at birth • Spherical form • Can be multiple • Lined with epithelium • Partial "double wall" due to ependymal folding • No hemosiderin • No septations • Germinolytic Cysts o Juxtaventricular subependymal pseudocysts • Result from germinolysis • Lined with germinal/glial cells (not ependymal cells) • May have hemosiderin • May have septations o Probably NOT normal variant • Rarely isolated, look for other signs of CNS pathology • Distinguish from connatal cysts

Asymmetric

lateral

Ventricles

(AlV)

=-

Axial TlAIR MR s!lows mild asymmetry ventricles. Right lateral ventricle is larger

of laleral bUl both

are normal in size. There is neither obstruction nor perivenuicular edema.

III

Helpful Clues for Rare Diagnoses • Open Inferior 4th Ventricle (Blake Pouch Remnant) o Presence of complete vermis, fastigial recess • Differentiates Blake pouch remnant from Dandy-Walker cyst o Usually non-obstructive o FIESTA, CSF flow sequences helpful

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SELECTED REFERENCES I.

2.

3.

4.

5.

6.

7.

8.

Kiroglu Y el al: Cerebral lateral ventricular asymmetry on CT: how much asymmetry is representing pathology? Surg Radiol Anal. 30(3):249-55, 2008 van Baalen A et al: Anterior choroid plexus cysts: distinction from germinolysis by high-resolution sonography. Pediatr Int. 50(1):57-61, 2008 Munoz A et al: Cisternography and ventriculography gadopentate dimeglumine-enhanced MR imaging in pediatric patients: preliminary report. AJNR Am J euroradiol: 28(5):889-94, 2007 Robinson AJ et al: The cisterna magna septa: vestigial remnants of Blake's pOlich and a potentia) new marker for normal development of the rhombencephalon. J Ultrasound Med. 26(1):83-95, 2007 Robinson AJ et al: The fetal cerebellar vermis: assessment for abnormal development by ultrasonography and magnetic resonance imaging. Ultrasound Q. 23(3):2) 1-23, 2007 Born CM et al: The septum pellucidum and its variants. An MRI study. Eur Arch Psychiatry Clin Neurosci. 254(5):295-302, 2004 Rohde V et al: Virtual MRI endoscopy: detection of anomalies of the ventricular anatomy and its possible role as a presurgical planning tool for endoscopic third ventriculostomy. Acta Neurochir (Wien). 143(11):1085-91, 2001 Bakshi R et al: Intraventricular CSF pulsation artifact on fast fluid-attenuated inversion-recovery MR images: analysis of 100 consecutive normal studies. AJNR Am J Neuroradiol: 2] (3):503-8,2000

Asymmetric

lateral

Ventricles

o' ::J (J)

(AlV)

Coronal T2WI MR s!lows mild bowing of seplalleaflets across midline without any evidence of interstitial edema. Upper third ventricle, Fornices are also sligl1tly displaced across midline.

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Artifact

Intraventricular CSF Pulsation (Flow-Related)

Intraventricular CSF Pulsation (Flow-Related)

Artifact

Intraventricular CSF Pulsation Artifact (Flow-Related)

(Left) Coronal FL4IR MR shows typical bilateral anterior horn CSF Ilow related pulsation artilact I:'JI. (Right) Coronal T1WI MR in the same case during the same examination shows absence of any mass or bleed within the normal-appearing anterior horns.

(Left) Axial rL4IR MR shows prominent, inhomogeneous signal within third ventricle ~ loramen 01 Monro I:'JI. (Right) Coronal T1 C+ MR shows prominent {Jow artifact in anleroinferior third ventricle. Artifact can mimic colloid cyst but fornices ~ are normal (colloid cysts typically in upper third ventricle, wedged between pillars 01 lornix).

=

Cavum Septi Pellucidi (CSP) ± Cavum Vergae (Left) Axial FL4IR MR shows cavum septi pellucidi PJ::l. The fornices are represented by tear drop-shaped thickenings allhe posterior aspect of the septalleallets I:'JI. Walls of CSP are parallel. (Right) Axial rL4/R MR in the same case as previous image, shows cavum septi pellucid; is continuous with patent cavum vergae. The septal leaflets are parallel and unbowed.

I 3 4

Artifact

VENTRICLES, NORMAL

VI

VARIANTS

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Coarctation

of Anterior

Horns

Coarctation

of Anterior

Horns (Left) Axial TI WI MR shows right caudate head "stuck" to anterior wall of anterior horn of lateral ventricle. Coaptated (coarcted) frontal, occipital

horns are not uncommon

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variants. (RighI) Axial T2WI MR shows similar ependymal attachment leading 10 coarctation of right anterior horn.

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Connatal

Cysts

Con natal Cysts (Left) Coronal ultrasound shows a tiny strand connecting the walls of the anterior horn in a premature infant on day I of life. (RighI) Sagittal T2WI MR shows the same cyst in the same patient during the neonatal period. Note the gestational age appropriate incomplete development of the gyri and sulci in this

=

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premature

Germinolytic

Cysts

Open Inferior 4th Ventricle Pouch Remnant)

inFant.

(Blake (Lefl) Axial FLAIR MR in

newborn with seizure shows subependymal cyst 1:7 along caudothalamic groove. A distinct fluid-fluid level within the cyst represents dependent layering of blood products. Small hemorrhagic germinolytic cyst arising from germinal matrix. (RighI) Sagittal T2WI MR shows incomplete closure of inFerior aspect of fourth ventricle. There is an increased angle ~ between the vermis and brainslem due to presence of Blake pouch remnant.

I 3 5

CHOROID PLEXUSLESIONS

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DIFFERENTIAL DIAGNOSIS Common • Choroid Plexus Cyst • Enlarged Choroid Plexus Less Common • Choroid Plexus Papilloma • Meningioma • Metastasis, Intraventricular • Ventriculitis/Plexitis • Sturge-Weber Syndrome • Neurofibromatosis Type 2

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Rare but Important • Choroid Plexus Carcinoma • Lipoma • Langerhans Cell Histiocytosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Most common cause of choroid plexus mass in adults is benign degenerative cyst Helpful Clues for Common Diagnoses • Choroid Plexus Cyst o Common incidental finding in older patients (40% prevalence); bilateral o In fetus, consider trisomy 18 or 21 • Enlarged Choroid Plexus o Normal in fetus, may be giant o May occur after hemispherectomy o May occur with collateral venous drainage (i.e., AVM,Sturge-Weber)

Choroid

I 3 6

Plexus Cyst

Axial T1 C+ M R shows choroid plexus xanthogranulomas 1::1. Common in the elderly, they are typically located in the lateral ventricle atria, within the choroid plexus glomus. Cyst walls may enhance.

Helpful Clues for Less Common Diagnoses • Choroid Plexus Papilloma o Strongly enhancing, lobulated intraventricular mass in child o Atrium of lateral ventricle 50%, left> right • Meningioma o Solid, enhancing intraventricular mass o Origin of intraventricular location related to embryological invagination of arachnoid cells into choroid plexus • Metastasis, Intraventricular o Enhancing choroid plexus mass • Ventriculitis/Plexitis o Enhancing ependyma & choroid plexus o Ventriculomegaly with debris level • Sturge-Weber Syndrome o Enlarged, enhancing "angiomatous" ipsilateral choroid plexus o May be only finding in first 6 months o Related to abnormal fetal cortical veins • Neurofibromatosis Type 2 o Extensive choroid plexus Ca++, uncommon manifestation Helpful Clues for Rare Diagnoses • Choroid Plexus Carcinoma o Enhancing intraventricular mass & ependymal invasion • Lipoma o Extra-axial mass with fat intensity o 40-50% interhemispheric fissure, may extend into choroid plexus • Langerhans Cell Histiocytosis: Rarely presents as enhancing choroid plexus masses

Choroid

Plexus Cyst

Axial ultrasound shows small choroid plexus cysts I!:11l within normal prominent echogenic choroid plexus 1::1The fetus also had a cardiac anomaly, overlapping fingers, & clubfeet; trisomy 18.

CHOROID

PLEXUS LESIONS

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(Left) Axial TI C+ MR shows a lobular, enhancing mass arising from the choroid plexus glomus "ydrocephalus often accompanies choroid plexus tumors &, may be related to mechanical obstruction or CSF overproduction. Frond-like morphology, internal flow voids & vibrant enhancement are characteristic. (Right) Axial T I C+ MR shows a uniformly enhancing mass in atrium of left lateral ventricle, the most

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location

intraventricular

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Ventricu Iitis/Plex itis (Left) Axial TI C+ FS MR shows an enhancing choroid plexus mass with subtle ependymal involvement 81.

Intraventricular metastases typically involve the choroid

plexus. Additional lesions are with intracranial metastatic disease. (Right) Coronal n C+ MR shows ventriculitis & plexilis, a complication of this patient's cerebral abscess &, meningitis. Note enlarged, enhancing choroid plexus E1 & intense ventricular wall enhancement. common

Sturge-Weber

Syndrome

Langerhans Cell Histiocytosis (Left) Axial TI C+ MR shows left cerebral hemiatrophy with compensatory thickening of the calvarial diploic space Serpentine leptomeningeal-pial enhancement &, hypertrophy of the ipsilateral choroid plexus ~ is typical. (Right) Axial TI C+ MR shows an enhancing granuloma in the choroid plexus in this child with systemic LCH. Perivascular spread of LCiI is also seen in the basal ganglia E1 as subtle enhancement.

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•

•

less Common • Metastases o Glioblastoma Multiforme o Lymphoma, Primary CNS o Germinoma o Medulloblastoma (PNET-MB) o Ependymoma o Choroid Plexus Carcinoma • Ventriculitis • Opportunistic Infection, AIDS Rare but Important • Neurosarcoid • TORCH, General • Vasculitis • Langerhans Cell Histiocytosis • Alexander Disease

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Ependyma is the thin epithelial membrane lining the ventricular system of the brain & spinal cord • Subependymallesions lie beneath the ependyma • Majority of ependymal/subependymal lesions are infectious or neoplastic Helpful Clues for Common Diagnoses • Normal Variant (Mimic) o Normal "indentations" into ventricles: Caudate heads, thalami, pes hippocampus, facial colliculus o Subependymal veins enhance & may mimic pathology • Tuberous Sclerosis Complex o Calcified subependymal nodules classic o Cortical/subcortical tubers at juxtacortical location

I 3 8

White matter lesions along lines of neuronal migration may extend to ependyma o Subependymal giant cell astrocytoma (SGCA) in 5-10% Subependymal Giant Cell Astrocytoma o Enlarging, enhancing intraventricular mass in patient with tuberous sclerosis complex o Typically at foramen of Monro Focal Cortical Dysplasia o Radially oriented white matter bands • Thin linear/wedge-shaped "comet-tail" shaped hyperintensities • Extend from ependymal to subcortical white matter • Best seen on FLAIR> T2WI o Associated with overlying cortical thickening • Mild mass effect common • Non-enhancing, mildly T2 bright o Imaging & histologic features similar to cortical/subcortical tubers of TSC Heterotopic Gray Matter o Nonenhancing nodules along inner ventricle margin o Gray matter signal on all sequences o May be associated with seizures or incidental Developmental Venous Anomaly o Enhancing "Medusa head" with enlarged draining vein o May have enlarged subependymal veins o Often occurs at angle of ventricle o Focal, unilateral lesion Multiple Sclerosis o Demyelinating process characterized by periventricular lesions o Enhancing lesions often extend to involve ependyma o Incomplete ring suggests demyelination o

DIFFERENTIAL DIAGNOSIS

•

•

•

Helpful Clues for less Common Diagnoses • Metastases o Etiology: CNS > systemic primaries • P ET-MBmost common (pediatrics) • GBM & anaplastic gliomas (adults) • Lymphoma/leukemia can seed CSF o Narrow differential by history & imaging • Ventriculitis o Ventriculomegaly with debris levels & ependymal enhancement

EPENDYMALISUBEPENDYMAL

LESIONS

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Periventricular T2 hyperintensity characteristic o Usually due to intraventricular rupture of adjacent brain abscess, meningitis or shunt complication • Opportunistic Infection, AIDS o Toxoplasmosis & lymphoma may extend along ventricular margins o CMV cause ventriculitis, meningitis or ischemia; ventriculitis common o TB may cause ventriculitis o

Helpful Clues for Rare Diagnoses • Neurosarcoid o Dural & leptomeningeal disease common o Ependymal, perivascular space enhancement o Pial enhancement with underlying white matter T2 hyperintensity characteristic o May involve choroid plexus & extend to ventricular margin • TORCH, General o Congenital infections caused by transplacental transmission of pathogens o White matter volume loss & T2 hyperintensity common to all TORCH infections o Periventricular calcification may be seen in CMV or Toxoplasmosis o CMV: Microcephaly, periventricular pseudocysts & hyperintensities; commonly associated with migrational disorders o Toxoplasmosis: Parenchymal & periventricular calcifications

Normal Variant (Mimic)

• Vasculitis o Suggested by linear enhancement along the course of deep white matter penetrating vessels o Enhancement may extend to ependyma o Usually associated with confluent surrounding T2 hyperintensity o DWI restriction is common • Langerhans Cell Histiocytosis o Rare subependymal involvement o May involve choroid plexus & mimic subependymal disease • Alexander Disease o Predilection for frontal lobes o Intense bands of enhancement in periventricular/subependymal location o Near complete lack of myelination in infants with large head suggest diagnosis Alternative Differential Approaches • Considerations in seizure patients: Tuberous sclerosis, heterotopic grey matter or focal cortical dysplasia • Lesions with minimal or no mass effect: Focal cortical dysplasia, ventriculitis, vasculitis, dysmyelinating conditions, TORCH • Mass lesions: Gray matter heterotopia, SGCA, metastases, lymphoma

Tuberous Sclerosis Complex

I Coronal T2WI MR shows normal hippocampal gray matter which line the temporal horns and should not be mistaken for heterotopia.

=.

=

Axial NECT shows mulUple calcified & non-calcified SlI subependymal nodules, characterisUc for tuberous sclerosis. Subependymaf nodules are present in 98% of TSCpatients.

3 9

EPENDYMAlISUBEPENDYMAllESIONS

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Focal Cortical

Dysplasia

(left) Axial CECT shows ventriculomegaly & a mixed calcified, cystic & solid subependymal giant cell astrocytoma E2 at the foramen of Monro. SCCAs are identified in 10-15% of patients with TSC. (Right) Coronal FU\IR MR shows a characteristic band of high signal =::I extending to the ependymal surface in conjunction with focafly thickened abnormal appearing cortex ~ in this patient

with focal cortical

dysplasia.

Heterotopic

Gray Matter

Developmental

Venous Anomaly

(left) Axial T2WI MR shows subependymalnodules of gray maller

=

lining inner

margin of lateral ventricles. Islands of left frontal dysplastic gray matter are also seen extending to the ventricle !:ll. (Right) Axial T1 C+ FS MR shows classic "Medusa head" of a

developmental venous anomaly. Dilated hair-like medullary veins converge on a single "collector vein II E2 that drains into subependymal venous system.

=

Multiple (left) Axial FU\IR MR shows a hyperintense mass-like lesion in a patient not previously diagnosed with MS. Note involvement of the corpus callosum !:ll & extension to the ventricular ependyma E2. (Right) Coronal T1 C+ MR shows a mass in the right temporal lobe biopsy proven GBM. A 4th ventricular mass ~ with subependymal

enhancement

= represents

CSF tumor spread.

I 3 10

Sclerosis

Glioblastoma

Multiforme

EPENDYMAlISUBEPENDYMAL

en ,.-

LESIONS

c: ell

::::l Co

...

to Choroid

Plexus Carcinoma

ell

::::l

(Lefl) Axial CECT shows perivenlricular

enhancement

!:::l representing subependymal spread of primary CNS lymphoma. Secondary lymphoma often causes dural disease. (RighI) Axial T7 C+ MR shows massive left lateral ventricle choroid plexus carcinoma ~ with multiple nodules of metastatic CSF spread

;:0 Cll
o ::::l Ul

Ventriculitis

Ventriculitis (Left) Axial T1 C+ MR shows striking ependymal enhancement around moderately enlarged lateral

-=

ventricles.

Ventriculitis

was

caused by rupture of an abscess in/a the left lateral ventricle. Several parenchymal

=

enhancing

foci

are also seen likely representing microabscesses. (RighI) Coronal FLAIR MR shows perivenlricular hyperintensity in CMV ventriculitis in this AIDS patient. CMV is a common

=

cause of ventriculitis

in AIDS

patients.

TORCH,

General

Alexander

Disease (Lefl) Axial NECT shows bilateral ventricular & basal ganglia calcification. Note the primitive appearance of the sylvian cisterns due (0 bilateral opercular polymicrogyria Elll!. The patient had microcephaly and venlriculomegaly

in

CMV infection. (Right) Axial CECT shows bilateral frontal deep white matter low density consistent with demyelination & symmetric enhancement of caudate heads, putamina, & frontal periventricuJar

E:I.

white matter

I 3 11

LATERALVENTRICLEMASS

en c

.Q Ol Ql

cr:

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DIFFERENTIAL DIAGNOSIS Common • Choroid Plexus Cyst • Intraventricular Hemorrhage • Neurocysticercosis Less Common • Choroid Plexus Papilloma • Meningioma • Metastasis, Intraventricular • Subependymal Giant Cell Astrocytoma (SGCA) • Central Neurocytoma • Subependymoma • Neurosarcoid • Ependymal Cyst Rare but Important • Choroid Plexus Carcinoma • Ependymoma • Cavernous Malformation • Lymphoma, Primary C S • Astrocytoma • Langerhans Cell Histiocytosis • Epidermoid Cyst • Teratoma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Lateral ventricle masses differentiated by o Location within lateral ventricle o Patient age

I 3 12

Helpful Clues for Common Diagnoses • Choroid Plexus Cyst o Most common intraventricular mass o Arise in choroid plexus glomus, degenerative (xanthogranulomas) o All ages (usually older patients) o Considered normal variant (40% prevalence); usually bilateral o Commonly FLAIR& DWI hyperintense o In fetus, consider Trisomy 18 or 21 • Intraventricular Hemorrhage o Typically related to trauma o Commonly associated with traumatic SAH o May be first presentation of AVM o May become Ca++ mass in chronic phase • Neurocysticercosis o Ventricle is 3rd most common location, after subarachnoid spaces & parenchyma

Intraventricular cysts are often isolated, 4th ventricle most common o Intraventricular lesions are best seen on FLAIR&T1 MR

o

Helpful Clues for Less Common Diagnoses • Choroid Plexus Papilloma o Most common primary intraventricular neoplasm of childhood o Top CNS neoplasm in children < 1 Y o Lateral ventricle atrium most common site o Hydrocephalus very common o May metastasize throughout CSF • Meningioma o 1-2% of meningiomas are intraventricular o Lateral ventricle atrium most common site, left> right o If seen in a child, consider NF2 o Lobular, strongly enhancing mass • Metastasis, Intraventricular o Intraventricular metastases much less common than parenchyma, skull/dura, subarachnoid disease o Usually lateral ventricle related to choroid plexus, ependyma less common o Primary tumor often known • Subependymal Giant Cell Astrocytoma (SGCA) o Enhancing mass at foramen of Monro in tuberous sclerosis (TS) patients o Occurs in 15% of TS patients o Often cause ventricular obstruction • Central Neurocytoma o "Bubbly" mass with enhancement o Frontal horn or body of lateral ventricle • Typically attached to septum pellucid urn o Ca++ common, 50-70% • Subependymoma o T2 hyperintense lobular, nonenhancing intraventricular mass o 4th ventricle> lateral> 3rd ventricle o Variable enhancement, often none to mild • Neurosarcoid o Solitary or multifocal enhancing CNS masses with lung disease o Dura, leptomeninges, subarachnoid spaces most commonly involved o Ventricular system variably involved, commonly associated with hydrocephalus • May involve choroid plexus • Ependymal Cyst o onenhancing thin-walled congenital cyst

lATERAL VENTRIClE

CII

MASS

" c::

o o

Follows CSF on all sequences Lateral ventricle atrium most common

site

Helpful Clues for Rare Diagnoses • Choroid Plexus Carcinoma o Enhancing intraventricular mass with ependymal invasion • Ependymoma o 4th ventricle> > > > lateral ventricle o 1/3rd supratentorial, majority periventricular white matter o Ca++ common (50%); ± cysts, hemorrhage • Cavernous Malformation o Ca++ & hemosiderin rim common o Rarely intraventricular, 2.5-11% of cases • Lymphoma, Primary CNS o Typically enhancing lesions within basal ganglia, periventricular WM o Often involve, cross corpus callosum o Frequently abut, extend along ependymal surfaces • Astrocytoma o Often spreads from corpus callosum into fornix or septum pellucidum o Primary intraventricular is less common o Typically frontal horn or body of lateral ventricle o Imaging varies with tumor grade • Langerhans Cell Histiocytosis o Rarely presents as enhancing choroid plexus masses • Epidermoid Cyst o Congenital epithelial inclusion cysts

Choroid

Plexus Cyst

Coronal T1 C+ MR shows classic choroid plexus

=

xanthogranulomas in an elderly patient. Contrast-enhanced scans show cyst walls enhance but contents do not. They are often FlAIR & OWl bright.

Follows CSF on all sequences except FLAIR &DWI • Teratoma o Midline mass containing Ca++, soft tissue, cysts, & fat o Intraventricular location is rare o

Alternative Differential Approaches • Lateral ventricle mass: Child o Choroid plexus papilloma> > carcinoma o SGCA (young adult) o Ependymoma • Lateral ventricle mass: Adult o Choroid plexus cyst> > neurocysticercosis o Meningioma o Metastasis o Central neurocytoma o Subependymoma o Lymphoma • Lateral ventricle mass: Location o Near/adjacent to foramen of Monro: SGCA, subependymoma, central neurocytoma o Body: Central neurocytoma, subependymoma o Atrium: Choroid plexus cyst, choroid plexus papilloma, metastasis, meningioma, ependymal cyst, choroid plexus carcinoma o All locations: Neurocysticercosis, neurosarcoid, lymphoma

Intraventricular

<

C1>

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Hemorrhage

Axial NECT shows traumaUc subarachnoid hemorrhage, hemorrhagic contusion & intravent.ricu/ar

=. =.

hemorrhage (lVH) Traumatic IVH is relatively uncommon & usually reflects severe injury.

I 3 13

LATERAL VENTRICLE MASS

(/)

c .Q OJ Q)

n:: Neurocysticercosis

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c III

Choroid

Plexus Papilloma

(Left) Axial FLAIR MR shows the colloidal vesicular stage of neurocysticercosis with intraventricular lesions ~. Often the eccentric scolex may be seen in the vesicular stage on T2/rLAIR & post-contrast images. (Right) Axial CECT shows lobulated, enhancing, trigonal mass with hydrocephalus. Margins of this choroid plexus papilloma show characteristic frond-like irregularities. Etiology of the hydrocephalus may be mass effect or CSF overproduction.

Metastasis,

Intraventricular

(Left) Axial T1 C+ FS MR shows large meningioma in the atrium of left lateral ventricle. Tumor has "trapped" occipita/8ll and temporal horns. IRight) Axial T1 C+ FS MR shows an enhancing mass in the frontal horn of the lateral ventricle in this patient with metastatic melanoma. Following resection of this mass, the patient developed additional brain parenchymal

=

metastatic

foci.

Subependymal (Left) Axial FLAIR MR shows a classic SCCA I:] in the foramen of Monro in this tuberous sclerosis patient. Moderate hydrocephalus & corticallUbers ~ are seen. (Right) Axial T1 C+ MR shows a bubbly mass in the body of the right lateral ventricle with heterogeneous enhancement & enlargement of the right frontal horn. The mass is attached to the septum pellucidum, typical of central neurocytoma.

I 3 14

Giant Cell Astrocytoma (SGCA)

Central Neurocytoma

LATERAL VENTRiClE

MASS

Ul

" c:

Neurosarcoid (Left) Axial FLAIR MR shows

a small mass in the left lateral ventricle near the septum pellucidum. There is no evidence of obstructive hydrocephalus. The mass is hyperintense to gray matter & did not enhance following contrast, typical of subependymoma. (Right) Axial T1 C+ MR shows intensely enhancing masses in the choroid plexi of both lateral ventricles & thickening of infundibulum ~. eNS involvement is seen in approximately 5% of sarcoid patients.

=

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~

Q: C1> en

;0 C1> <0

o

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en

(Left) Coronal T1 C+ MR shows an ependymal cyst in the enlarged atrium of the left lateral ventricle. Note the thin cyst wall & displaced choroid plexus This was

==.

an incidental

finding.

The

lateral ventricle atrium is the most common site. (Right) Axial T2WI MR shows an ependymoma in the atrium of the right lateral ventricle. Note flow voids &J and extensive perilumoraf edema [<±. Most supralenwrial ependymomas are parenchymal.

Teratoma (Left) Axial T1 C+ MR shows subependymal spread of lymphoma. Primary CNS lymphoma is classically

=

located

WM

in perivenlricular

& abuts &/or extends

along ependymal surfaces as in this case. (Right) Axial T1WI MR shows heterogeneous mass with scallered small hyperintense foei, consistent with fat ~ & marked ventricular dilatation. Presence of fat & Ca++ indicates teratomatDus histology rather than choroid plexus tumor or ependymoma.

I 3 15

THICK SEPTUM PELLUCIDUM

CJ)

c

.2

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DIFFERENTIAL DIAGNOSIS Common • Cavum Septi Pellucidi (CSP) • Astrocytoma

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CO "C

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ttl

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Less Common • Lymphoma, Primary CNS • Germinoma • Metastasis, Intraventricular • eurofibromatosis Type 1 Rare but Important • Alexander Disease • Fused Fornices (Holoprosencephaly)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Septum pellucid urn should be 2 mm or less • Any neoplasm with propensity for ependymal/subependymal spread may cause thickened septum pellucidum Helpful Clues for Common Diagnoses • Cavum Septi Pellucidi (CSP) o Cystic CSF cavity of septum pellucidum between frontal horns, normal variant o Follows CSF on all sequences o May have associated mass effect • Astrocytoma o Often involves septum pellucidum from ependymal spread or corpus callosum o Primary tumor of septum pellucid urn rare o Imaging varies with tumor grade

Helpful Clues for Less Common Diagnoses • Lymphoma, Primary CNS o Enhancing lesions in basal ganglia or periventricular white matter typical o Often extend along ependymal surfaces • Germinoma o Ventricular disease related to CSF seeding o Primary intraventricular germinoma, rare • Metastasis, Intraventricular o May involve septum pellucidum by ependymal spread o Gray-white junction lesions most common • Neurofibromatosis Type 1 o Thickening related to presumed hamartomatous involvement of forniceal columns as they pass through septal leaves o Hypothalamic tumors may also infiltrate septum pellucidum Helpful Clues for Rare Diagnoses • Alexander Disease o Diffuse, symmetric bifrontal white matter disease in a macrocephalic infant o Columns of fornix/septum pellucidum may be involved o Enhancing periventricular rim, particularly around frontal horns in early disease • Fused Fornices (Holoprosencephaly) o Fused fornices is a specific sign (lobar), may mimic thick septum pellucidum o Absent septum pellucidum o Frontal lobe hypoplasia

Cavum Septi Pellucidi (CSP)

I 3 16

Axial T7 WI MR shows the classic appearance of CSP with posterior extension into a cavum vergae, seen as a CSF-signal collection between the bodies of the

=

lateral ventricles.

Axial T1 C+ MR shows enhancing mass infiltrating fornices, corpus callosum splenium, and septum pellucidum Glioblastoma mu/tiforme found at biopsy.

=.

THICK SEPTUM PElLUCIDUM

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c: " Ql

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(Left) Coronal T1 c+ MR shows an enhancing left insular mass with ependymal spread of tumor causing thickening & enhancement of the septum pellucidum. (Rig/It) Axial T1 C+ MR shows subependymal spread with involvement of the septum pellucidum. Primary CNS lymphoma is classically located

in

peri ventricular

white matter & abuts &/or extends along ependymal surfaces. Involvement of leptomeninges or dura is

more common in secondary

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co

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lymphoma.

(Left) Axial NECT shows hyperdense ventricular metastases related 10 germinoma. There is extensive tumor along the lateral ventricles & filling the occipital horns. (Right) Axial T1 C+ MR shows ependymal spread of metastatic melanoma.

While primary

malignant brain tumors such as GBM, germinoma, & lymphoma commonly spread along ependyma, this is a recognized but uncommon site for tumor deposits from extracraniaf neoplasms.

(Left) Axial T2WI MR shows thickening of the septi pellucidi in this NFl patient, presumed to represent hamartomatous

=

infiltration.

Note also Focal

areas of increased signal intensity in the globus pallidus bilaterally. (Right) Axial T1 C+ MR shows fullness & increased enhancement

P.:D as

in the fornices

well as abnormal

signal in the {rontal while mailer, caudate heads, & anterior putamina, typical of infantile Alexander disease.

I 3 17

FORAMEN

(J)

c:

OF MONRO

MASS

.Q Ol Q)

~

DIFFERENTIAL DIAGNOSIS Common • CSF Flow Artifact • Cavum Septi Pellucidi (CSP) • Colloid Cyst

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Q)

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Less Common • Neurocysticercosis • Tuberous Sclerosis Complex (Subependymal Nodule) • Subependymal Giant Cell Astrocytoma (SGCA) • Metastasis, Intraventricular • Astrocytoma (Fornix, Septum Pellucidum) • Subependymoma • Central Neurocytoma • Germinoma • Vertebrobasilar Dolichoectasia (VBD) Rare but Important • Choroid Plexus Papilloma • Choroid Plexus Cyst • Cavernous Malformation • Ependymal Cyst • Alexander Disease

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Foramen of Monro connects inferior lateral ventricles with 3rd ventricle • Majority of foramen of Monro lesions are related to flow artifact or a normal variant • Colloid cyst is most common, representing 15-20% of intraventricular masses • SGCA is most common in a child • Age is a helpful differentiating feature

I 3 18

Helpful Clues for Common Diagnoses • CSF Flow Artifact o Mu1tiplanar technique confirms artifact o Look for phase artifact • Cavum Septi Pellucidi (CSP) o Cystic CSF cavity of septum pellucidum between frontal horns, normal variant o Often associated with a posterior continuation, cavum vergae o Follows CSF on all sequences o May have associated mass effect • Colloid Cyst o Hyperdense mass at foramen of Monro on CT is characteristic

o o o

Pillars of fornix straddle, drape around cyst Attached to anterior 3rd ventricular roof Cysts typically do not enhance, but may have "rim-enhancement" on MR

Helpful Clues for Less Common Diagnoses • Neurocysticercosis o Cyst with "dot" inside (vesicular stage) o Convexity subarachnoid spaces most common; ventricles least common o Intraventricular cysts are often isolated o Imaging varies with development stage, host response • Tuberous Sclerosis Complex (Subependymal Nodule) o Calcified subependymal nodules 98% o Cortical/subcortical tubers, 70-95% o White matter lesions along lines of neuronal migration o If subependymal nodule at foramen of Monro enlarges, likely a SGCA • Subependymal Giant Cell Astrocytoma (SGCA) o Enhancing mass at foramen of Monro in tuberous sclerosis (1'S)patients o Occurs in 15% of TS patients o Often cause ventricular obstruction • Metastasis, Intraventricular o Primary tumor often known o Often multiple lesions at gray-white junctions o Typically involve choroid plexus if intraventricular • Astrocytoma (Fornix, Septum pellucidum) o Often spreads into fornix or septum pellucidum from corpus callosum o Primary tumor involvement less common o Imaging varies with tumor grade • Subependymoma o 1'2 hyperintense, lobular, nonenhancing, intraventricular mass o Intraventricular, inferior 4th ventricle typical (60%) • Lateral & 3rd ventricles less common o Lateral ventricle: Attached to septum pellucidum or lateral wall o May occur at foramen of Monro o Typically no or mild enhancement • Central Neurocytoma o "Bubbly" mass with moderate to strong enhancement

FORAMEN

OF MONRO

Lateral ventricle, attached to septum pellucid urn • Germinoma o Propensity to hug midline near the 3rd ventricle - 80-90% o Pineal region: 50-65%; suprasellar: 25-35% o Primary intraventricular germinoma is rare, typically 3rd ventricle o Ventricles often involved by CSF seeding • Vertebrobasilar Dolichoectasia (VBD) o Long segment irregular fusiform or ovoid arterial dilatation o Typically occurs in vertebrobasilar system more than carotid • Extreme VBD can cause hyperdense foramen of Monro mass o Look for "flow void", phase artifact on MR o CTA is also diagnostic for this pseudomass o

Helpful Clues for Rare Diagnoses • Choroid Plexus Papilloma o Enhancing ventricular papillary mass with hydrocephalus in a child o Atrium of lateral ventricle most common location (50%) o 3rd ventricle primary is less than 10% • Choroid Plexus Cyst o Typically bilateral & arise in choroid plexus glomus of adults o Considered part of normal aging o May rarely occur in foramen of Monro o Commonly DWI & FLAIRhyperintense • Cavernous Malformation

CSF Flow Artifact

en

MASS

" c:

Ca++ & T2 hypointense hemosiderin rim common o Rarely intraventricular, 2.5-11% of cases • Ependymal Cyst o Nonenhancing thin-walled congenital cyst with CSF density/intensity o Intraventricular common, typically lateral ventricle • Alexander Disease o Diffuse, symmetrical bifrontal WM disease in macrocephalic infant o Thick enhancing periventricular rim (particularly around frontal horns) o Intense enhancement characteristic of early disease o Columns of fornix often involved o

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Alternative Differential Approaches • Foramen of Monro mass: Adult o Pseudomass: CSF flow artifact, VBD, CSP o Colloid cyst o Neurocysticercosis o Metastasis, intraventricular o Astrocytoma o Subependymoma o Central neurocytoma o Choroid plexus cyst • Foramen of Monro mass: Child o Cavum septi pellucidi (CSP) o Tuberous sclerosis complex/SGCA o Germinoma o Choroid plexus papilloma o Ependymal cyst o Alexander disease

Cavum Septi Pellucidi (CSP)

I

=-

Axial TI WI MR shows a flow arUfact in & around the 3rd venlnde & foramen of Monro which mimics a mass. A flow artifact is typically seen on [LAIR images. Multiplanar technique confirms artifact

Coronal T7

c+

MR shows an unusually large cavum

septi pellucidi with mass effect. There is lateral bowing of the leaves of the septum pellucidum & lateral displacement of the foramen of Monro

=.

3 19

FORAMEN OF MONRO

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MASS

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(Left) Axial T1 WI MR shows a hyperintense lesion allhe foramen of Monro. Note draping of fornices over the cyst classic for colloid cyst. These are typically hyperdense on CT & may present acutely with hydrocephalus. (Right) Coronal T1 C+ MR shows a farge cystic intraventricular mass 1:1 with an enhancing nodule. Intraventricular cysts

=

are not uncommon

in

neurocyslicercosis, but a lesion of this size is unusual.

Intraventricular cysts are often isolated.

Tuberous Sclerosis Complex (Subependymal Nodule) (Left) Axial NECT shows calcified subependymal nodules at the foramen of Monro & low density cortical & subcortical tubers typical or tuberous scferosis. If a subependymal nodule at the foramen of Monro enlarges, SCCA is likely. (Right) Coronal T1 C+ MR shows a right foramen of Monro mass II] in a tuberous sclerosis patient, (a SCCA). Note small enhancing subependymal nodule in left foramen of Monro. SCCAs are WHO grade I tumors.

=

=

Astrocytoma (Fornix, Septum Pellucidum) (Left) Axial T1 C+ FS MR shows an enhancing renal cell carcinoma metastasis It] at the foramen

of Monro

with associated hydrocephalus

which mimics

a SCCA. Typically, intraventricular

metastases

occur in the choroid plexus. (Right) Axial CECT shows a

I 3 20

heterogeneously enhancing mass that appears to have arisen within & thickened the septum pellucidum. Note ependymal spread ~ in this glioblastoma multiforme patient with CSF seeding.

FORAMEN OF MONRO

MASS

Ul

c: " III

::l

Q.

..•

lJl III

Central Neurocytoma (Left) Axial T7 C+ MR shows an enhancing mass at the foramen of Monro, attached 10 the septum pellucidum . Typically these tumors have no or mild enhancement & are asymptomatic. (Right) Coronal T7 C+ MR shows a heterogeneous "bubbly" ventricular mass with bowing of the septum pellucidum. Central neurocytomas are typically located in the lateral ventricle, atlached to the septum pellucidum. "ydrocephalus related to foramen

Vertebrobasilar

Dolichoectasia

< Cl>

-ro..• ::l

o· (J)

of Monro

obstruction

Germinoma

::l

is common.

(VBD) (Left) Axial TI C+ MR shows multiple masses related to synchronous pineal & suprasellar germinomas. Enhancing

tumor infiltrates

the ependyma of the frontal horns & anterior columns of the fornix E:II at the foramen of Monro. Tumar seeding & brain invasion are common

findings with CNS germinoma. (Right) Axial NECT shows a slightly hyperdense "mass" at the foramen of Monro The mass was caused by extreme fusiform ectasia of the basilar artery.

=.

Cavernous Malformation

Alexander

Disease (Left) Axial T7WI MR shows multiple Jocules with mixed signal intensity, consistent with hemorrhages of different ages in this cavernous

malformation.

(Right) Coronal T7 C+ MR shows full forniceal columns with marked enhancement ~. Enhancement corresponds 10 foci of Rosenthal fiber accumulation. There is also subtle enhancement around the frontal horns. Diagnosis

required brain biopsy in the past

Testing for mutations

CFAP are now possible.

in

I 3 21

THIRD VENTRICLEMASS, GENERAL

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DIFFERENTIAL DIAGNOSIS Common • MR Artifacts, Flow-Related • Massa lntermedia, Normal • Colloid Cyst Less Common • Germinoma • Neurocysticercosis • Neurosarcoid • Prominent Massa Intermedia, Chiari 2 • Vertebrobasilar Dolichoectasia (Mimic) Rare but Important • Choroid Plexus Papilloma • Craniopharyngioma • Pituitary Macroadenoma • Tuber Cinereum Hamartoma • Chordoid Glioma • Lymphoma, Primary CNS • Langerhans Cell Histiocytosis • Glioma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Vast majority of 3rd ventricular "masses" are artifact or normal anatomy • Colloid cyst is only common lesion that is classically located in 3rd ventricle • These masses often occur in other locations but may occur primarily in 3rd ventricle o Germinoma, choroid plexus papilloma, craniopharyngioma, macroadenoma, lymphoma, hypothalamic hamartoma • Newly described rare tumor, chordoid glioma is primary to 3rd ventricle

I 3 22

Helpful Clues for Common Diagnoses • MR Artifacts, Flow-Related o May be differentiated from true mass by associated phase artifact o Multiplanar technique confirms artifact • Massa Intermedia, Normal o Normal grey matter connection of medial thalamus (interthalamic adhesion) o Absent in up to 20% of human brains o Unclear function • Colloid Cyst o 99% wedged into foramen of Monro o Attached to anterior 3rd ventricular roof o Pillars of fornix straddle, drape around cyst

o

Posterior part of frontal horns splayed laterally around cyst

Helpful Clues for Less Common Diagnoses • Genninolna o CNS germinomas have a propensity to hug the midline near 3rd ventricle - 80-90% o Location: Pineal region - 50-65%; suprasellar - 25-35%; basal ganglia and thalami - 5-10% o Primary intraventricular germinoma involving 3rd ventricle is rare o Ventricles usually involved from CSF dissemination • Neurocysticercosis o Convexity subarachnoid spaces most common location o May involve cisterns> parenchyma> ventricles o Intraventricular cysts are often isolated, 4th ventricle most common • Neurosarcoid o Solitary or multifocal C S mass(es) with lung disease o Location: Dura, leptomeninges, subarachnoid space most common • Often involves basal cisterns, particularly optic chiasm, hypothalamus, infundibulum, cranial nerves o Brain parenchyma: Hypothalamus> brain stem> cerebral> cerebellar hemispheres o Ventricular system variably involved, commonly associated with hydrocephalus • Prominent Massa Intermedia, Chiari 2 o Large massa intermedia, typical of Chiari 2 o Third ventricle may be high-riding if corpus callosum agenesis present • Vertebrobasilar Dolichoectasia (Mimic) o Long segment irregular fusiform or ovoid arterial dilatation o Typically occurs in vertebrobasilar system more than carotid circulation o Ectatic basilar artery may indent 3rd ventricle and/or foramen of Monro o MR (flow artifact) or CTA is diagnostic Helpful Clues for Rare Diagnoses • Choroid Plexus Papilloma o Strongly enhancing, lobulated, intraventricular mass in child o Location: Atrium of lateral ventricle (50%),

left> right; 4th ventricle (40%) o

3rd ventricle primary less than 10%

THIRD

VENTRIClE

MASS, GENERAL

CIl

c: ""

• Craniopharyngioma o Partially cystic/solid, calcified suprasellar mass in child o Location: Suprasellar (75%); suprasellar and intrasellar (21%); intrasellar (4%) o Rare ectopic locations: 3rd ventricle, nasopharynx, sphenoid sinus • Pituitary Macroadenoma o Enhancing sellar and suprasellar mass o Rarely have ectopic origins outside pituitary fossa • 3rd ventricle, sphenoid or cavernous sinus, pituitary stalk • Tuber Cinereum Hamartoma o Nonneoplastic congenital collection of heterotopic neurons and glia originating from tuber cinereum (3rd ventricle floor) o Small (typically - 1 em), round, mass contiguous with tuber cinereum o Sessile or pedunculated round mass, similar in density/intensity to gray matter o T1 C+: Nonenhancing (if enhances, consider glioma or other tumor) • Chordoid Glioma o Rare, slow growing, non-invasive glial tumor of 3rd ventricle o Enhancing mass in anterior 3rd ventricle contiguous with hypothalamic or suprasellar structures • Lymphoma, Primary CNS o Enhancing lesion in basal ganglia or peri ventricular white matter o Commonly abuts or extends along ependymal surface

MR Artifacts,

• Langerhans Cell Histiocytosis o Proliferation of Langerhans cell histiocytes forming granulomas in any organ system o Often thick enhancing infundibulum, absent posterior pituitary bright spot o Rarely presents as enhancing choroid plexus masses, nodules of leptomeninges, basal ganglia, cerebellar white matter, and brain parenchyma • Glioma o Primary astrocytomas and ependymomas of 3rd ventricle are rare o Imaging depends on tumor type and grade

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~

:0. Q. <1l C/l

Alternative Differential Approaches • 3rd ventricle mass: Adult o Pseudomass: MR artifacts, flow-related, vertebrobasilar dol ichoectasia o Colloid cyst o Neurocysticercosis o Neurosarcoid o Pituitary macroadenoma o Chordoid glioma • 3rd ventricle mass: Child o Germinoma o Choroid plexus papilloma o Craniopharyngioma o Tuber cinereum hamartoma o Langerhans cell histiocytosis

Flow-Related

Coronal T1 C+ MR shows a lIow artifact in the 3rd ventricfe which can mimic a ventricular mass Often an associated phase artifact is seen. Multiplanar technique confirms the artifact.

=.

Axial T1WI MR shows the normal massa intermedia (interlhalamic adhesion) as it connects Ule medial thalami This normal anatomic connection may occasionally mimic a mass.

=.

I 3 23

THIRD VENTRICLE MASS, GENERAL

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shows an enhancing tumor

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Germinoma

Colloid Cyst (Left) Axial NECT shows a classic hyperdense colloid cyst in the anterior 3rd ventricle, causing mild hydrocephalus. NOle lhe Fornices =.:I are draped and splayed around lhe mass. (Right) Axial T1 C+ MR projecting From lhe pineal region in/a lhe poslerior 3rd ventricle. Germinomas are

the most common in the pineal region and lypically involve lhe venlricles by spread.

csr

Neurocysticercosis (Left) Axial T2WI MR shows neurocysLicercus cyst in Jrd ventricle ~ causing acute,

severe obstructive hydrocephalus wilh lransependymal CSF flow =.:I. (Right) Coronal T1 C+ MR shows mulliFocal, dural, parenchymal, & venlricular masses in a sarcoid patient Involvement of lareral ventricles is much more common than 3rd ventricular =.:I disease. CNS is involved in 5-15 % of cases.

Prominent (Left) Axial T2WI MR shows lypical Features of a Chiari 2 malformation including an

enlarged massa intermedia !:l:I and colpocephaly. An enlarged massa intermedia may occasionally mimic a 3rd ventricular mass. A high-riding 3rd venlricle may also be seen if there is agenesis of corpus callosum. (Rig"') Axial CECT shows an

enhancing

I 3 24

II

mass at II

foramen of Monro m. Initial diagnosis was colloid CYSI. MR showed high flow caused by extreme FusiForm ectasia of the basilar artery.

Massa Intermedia,

Chiari 2

Vertebrobasilar

Dolichoectasia

(Mimic)

,..c:

CIl

THIRD VENTRICLE MASS, GENERAL

III

::l

Co

OJ .,

Choroid

Plexus Papilloma

III

Craniopharyngioma (Left) Axial CECT shows an enhancing lobular mass arising from the roof of the 3rd ventricle with significant associated hydrocephalus in this child. The imaging appearance is typical, but the location is unusual for a choroid plexus papilloma. (Right) Coronal TfWI MR shows a homogeneously hyperintense mass, likely a reflection of cholesterol-laden fluid, filling the 3rd ventricle. These suprasellar masses rarely

occur in the 3rd ventricle.

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< CD ;:.

:0.

n

CD (J)

;u CD

(Q

o· ::l (J)

(Left) Axial Tf C+ MR shows an invasive macroadenoma that extends from the sellar

and suprasellar regions into the 3rd ventricle!:l1. Ectopic pituitary macroadenomas may rarely occur;, primarify in the 3rd ventricle. (Right) Sagittal Tf WI MR shows a round mass contiguous

=

with the tuber cinereum within the 3rd ventricle, isoimense to gray matter. No enhancement is typical. If

enhancement is seen, must consider glioma or other tumors.

Glioma (Left) Axial T I C+ MR shows an enhancing mass in 3rd ventricle This rare tumor is found only in anterior 3rd ventricle & is associated with hydrocephalus & compression of adjacent structures. (Right) Axial Tf C+ MR shows an enhandng mass in upper 3rd ventricle =::I in a child, just be/ow foramen of Monro. Note associated hydrocephalus. Astrocytoma diagnosed at surgery. Initial pre-operative diagnosis was choroid plexus papilloma, although no lobulation was seen.

=.

I 3 25

THIRD VENTRICLE

(IJ

c

MASS, BODY/POSTERIOR

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ell

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• Neurocysticercosis o Cystic lesion typically slightly hyperintense to CSF o ± Discrete eccentric scolex o Cisterns> parenchyma> ventricles

DIFFERENTIAL DIAGNOSIS Common • Pulsatile CSF • Dilated Suprapineal • Neurocysticercosis

Recess

Less Common • Germinoma • Prominent Massa Intermedia, • Choroidal Metastases • Choroid Plexus Papilloma

Chiari 2

Rare but Important • Xanthogranuloma • Ependymal Cyst

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • True primary posterior 3rd ventricle masses rare • Most represent extension from pineal pathology Helpful Clues for Common Diagnoses • Pulsatile CSF o 2° to time-of-flight effects/turbulent flow o t With thinner slices, longer TE, imaging perpendicular to flow o Evaluate other planes for real vs. artifact • Dilated Suprapineal Recess o Chronic aqueductal stenosis (any etiology) o Third ventricle dilates o May deform rostral tectum, mimic tectal glioma

Pulsatile CSF

I 3 26

=

this as flow artifact.

Helpful Clues for Rare Diagnoses • Xanthogranuloma o CT variable o MR Tl iso-hyper/T2 hyperintense o Lateral> > 3rd ventricle o Obstruction infrequent (3rd > lateral) • Ependymal Cyst o Nonenhancing thin-walled cyst o CSF density/intensity o Rare in 3rd ventricle

Dilated Suprapineal

Axial FLAIR MR shows CSF flow anomaly manifesUng as a hypoinlense "pseudolesion" of the posterior 3rd ventricle. Examining other sequences & planes confirmed

Helpful Clues for Less Common Diagnoses • Germinoma o Usually extension from pineal tumor o Strong enhancement, ± CSF seeding o Restricted diffusion due to high cellularity • Prominent Massa Intermedia, Chiari 2 o Large mass a intermedia typical of Chiari 2 • Choroidal Metastases o Tl hypo T2 hyperintense; avidly enhance o Lateral ventricles> 3rd > 4th • Choroid Plexus Papilloma o Strongly enhancing, lobulated mass o Hydrocephalus, t intracranial pressure 2° to increased CSF production o Lateral ventricle> > 3rd

Recess

Sagillal T2WI MR reveals dilated suprapineal recess -? from chronic aqueductal stenosis !:l2. Note dilated lateral venfJicJe with upward bowing of corpus callosum ~ flallened fornices f2iJ.

THIRD VENTRICLE MASS, BODY/POSTERIOR

CJl

c: ""

Neurocysticercosis (LeFt) Axial T7 C+ MR demonstrates a classic

neurocyslicercosis

cyst

=

with an enhancing nodule representing the scolex 811(Right) Sagi!!al T7 C+ MR shows a robustly enhancing, predominantly solid tumor that Fil/sthe posterior 3rd ventricle, suprapineal recess, and inferior recesses DJ. The pineal gland appears engulFed by the mass and is probably the source of the

;0 (1)

tumor.

<0

o OJ Ul

Prominent

Massa Intermedia,

Chiari 2

Choroidal

Metastases (Left) Axial T2W/ MR shows an enormous massa intermedia ~ that nearly fills the entire third ventricle.

(Right) Axial T1W/ MR reveals two lesions which are isoinlense with gray maller =:I that are pineal & suprasellar masses involving the 3rd ventricle. Biopsy disclosed embryonal carcinoma.

Xanthogranuloma (Left) Axial rU\/R MR shows a heterogeneous mass involving the posterior 3rd

=

ventricle.

Note

ventriculomegalyand transependymal CSF resorption

E:I from

obstructive hydrocephalus. (Right) Axial N[CT demonstrates a close-up view of a hyperdense mass in the 3rd ventricle =:I.

I 3 27

CEREBRAL AQUEDUCT/PERIAQUEDUCTAL

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LESION

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Common • Aqueductal Stenosis • Tectal Glioma Less Common • Diffuse Axonal Injury (DAI) • eurocysticercosis • Multiple Sclerosis • Enlarged Perivascular Spaces • Diffuse Astrocytoma, Low Grade • Encephalitis (Miscellaneous) • Intraventricular Hemorrhage • Wilson Disease Rare but Important • Metastasis, Parenchymal • Wernicke Encephalopathy • Behc;:et Disease • Gliomatosis Cerebri (GC) • Leigh Syndrome • Alexander Disease

•

•

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Cerebral aqueduct/periaqueductallesions may be separated by lesion type o Masses & pseudomasses o Infectious/inflammatory processes versus metabolic disorders Helpful Clues for Common Diagnoses • Aqueductal Stenosis o Focal reduction in aqueduct size, congenital or benign acquired o Funnel-shaped aqueduct with "ballooned" lateral & 3rd ventricles & foramen of Monro proximal to obstruction o Normal 4th ventricle & foramina distal o All patients with suspected AS should be scrutinized for an obstructing mass! • Tectal Glioma o t T2 signal mass; ± enhancement o Expands tectum, obstructs aqueduct o Indolent, most only need CSF diversion

I 3 28

Helpful Clues for Less Common Diagnoses • Diffuse Axonal Injury (DAI) o Multifocal punctate hemorrhages at corticomedullary junction, corpus callosum, deep gray matter (GM) & upper brainstem (dorsolateral midbrain & pons)

Multifocal hypointense T2*/GRE foci related to blood product susceptibility Neurocysticercosis o Cisterns> parenchyma> ventricles o Basal cistern cysts may be racemose (grape-like), causing an aqueduct lesion Multiple Sclerosis o Multiple T2 hyperintensities in periventricular white matter (WM) & callososeptal interface; 10% infra tentorial o Internuclear ophthalmoplegia (I 0): Characteristic clinical finding related to brainstem lesion involving medial longitudinal fasciculus, present within periaqueductal region Enlarged Perivascular Spaces o Benign fluid-filled structures, accompany penetrating arteries o PVS usually 5 mm or less; may expand o Most common location for expanded "giant" PVS is midbrain; may cause hydrocephalus o Single or multiple well-delineated cysts isointense with CSF; no enhancement Diffuse Astrocytoma, Low Grade o Nonenhancing T2 hyperintense mass; supratentorial 2/3, infra tentorial 1/3 o 50% of brains tern "gliomas" are low grade astrocytoma • Occur in pons & medulla of children, may involve midbrain o Usually no enhancement, if C+ worry about malignant progression Encephalitis (Miscellaneous) o Location dependent on etiology o Diffuse brain parenchymal inflammation caused by a variety of pathogens, most commonly viruses o Abnormal T2 hyperintensity of GM ± WM or deep gray nuclei o Epstein-Barr virus: Symmetric BG, thalami, cortex, or brainstem o Varicella-zoster virus: Brainstem/cortical GM, cranial nerves o Japanese encephalitis: Bilateral thalami, brainstem, cerebellum, spinal cord, cerebral cortex o Listeria rhombencephalitis: Brainstem & cerebellum o

DIFFERENTIAL DIAGNOSIS

•

•

CEREBRALAQUEDUCT/PERIAQUEDUCTAllESION West Nile virus: Brainstem, substantia nigra, BG, thalami, anterior horn (cord), cerebellum o Enteroviral encephalomyelitis: Brainstem, spinal cord, & cerebellum • Intraventricular Hemorrhage o Associated with significant trauma o May occur within cerebral aqueduct • Wilson Disease o Symmetric T2 hyperintensity or mixed signal in putamen, globus pallidus (GP), caudate, & thalami o Characteristic "face of the giant panda" sign at midbrain o

Helpful Clues for Rare Diagnoses • Metastasis, Parenchymal o May involve brainstem; typically multiple lesions • Wernicke Encephalopathy o Curable neurologic disease caused by thiamine deficiency o Triad of neuro-ophthalmologic manifestations, ataxia, & global confusion o Symmetric increased T2 signal surrounding aqueduct & 3rd ventricle, floor of 4th ventricle & medial thalami o May affect only periaqueductal grey matter • Behc;:etDisease o Multisystem vasculitis of unknown origin, CNS involvement 5-10% o Classic triad of oral & genital ulcerations with uveitis

Aqueductal

T2 hyperintense lesions in brainstem, BG &/or deep WM o Variable enhancement • Gliomatosis Cerebri (GC) o T2 hyperintense infiltrating mass with enlargement of involved structures, no or minimal enhancement o Brainstem involvement 10-15% • Leigh Syndrome o Lesions predominantly in brainstem, BG (particularly putamen) & cerebral WM o Bilateral, symmetric increased T2 in putamina & periaqueductal gray matter o Edema characteristic of early disease • AJexander Disease o Diffuse, symmetric, bifrontal WM signal abnormality & enhancement o Obstructive hydrocephalus, especially neonatal/infantile subtypes 2° to aqueduct obstruction from periaqueductal disease o

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Alternative Differential Approaches • Masses: Tectal glioma, NCC, PVS, diffuse astrocytoma, metastases, GC • Pseudomasses: AS, encephalitis, Behc;:et • Infectious/Inflammatory: MS, encephalitis, Behc;:et • Metabolic: Wilson disease, Wernicke encephalopathy, Leigh syndrome, Alexander disease

Tectal Glioma

Stenosis

Sagittal T1WI MR shows large lateral & 3rd ventricles, with a normal 4th. The "funnel-shaped" stenotic aqueduct SI & dilated optic & infundibular recesses of the 3rd ventricle are well seen I!::l.

C/l

Sagittal T2WI MR shOl'VSa tecta I plate glioma ~ as a homogeneous, mildly T2 hyperintense mass. Lesions in this location often cause obslructive hydrocephalus,

requiring shunting.

I 3 29

CEREBRAL AQUEDUCT/PERIAQUEDUCTAL

C/)

c

o en Ql 0::

Neurocysticercosis

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C/) Ql

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LESION

(Left) Axial NECT shows OAI in dorsolateral midbrain a common location in the brainstem. This traumatic axonal Slrelch injury typically occurs at corlicomedullary junctions, along corpus callosum, deep gray mailer & upper brainslem. (Right) Sagillal TI WI MR shows enlarged lateral ventricles & a large cystic intravenlricular mass with a nodule 81. NCC may cause a periaqueductal lesion from an intraventricular lesion or racemose NCC in lhe basal cisterns.

Multiple

Sclerosis

Enlarged Perivascular Spaces

(Left) Axial T2WI MR shows a round hyperintense MS plaque in the midbrain leg mentum involving the anterior periaqueduclal gray maller. A lesion in this location often causes internuclear ophthalmoplegia (lNO), a clinical finding characteristic of MS. (Right) Sagillal T IWI MR shows markedly enlarged perivascular spaces resulting in a periaqueductal lesion. When these spaces become markedly enlarged, they most commonly aFFecl the midbrain.

=

Diffuse Astrocytoma,

I 3 30

(LeFt) Sagillal T2WI MR shows a foca/tegmental mesencephalic glioma PJ::i:I involving midbrain 8cerebral peduncle. Mass effect from lUmors in this location oflen result in hydrocephalus, requiring shunting. Brainstem gliomas typically involve pons. (Right) Axial fLAIR MR shows t signal within lhe midbrain I:] relaled 10 West Nile encephalitis. Brainstem, cerebellum, basal ganglia, & thalamic involvement is classic For West Nile encephalitis.

low Grade

Encephalitis

(Miscellaneous)

CEREBRAL AQUEDUCT/PERIAQUEDUCTAL

LESION

CJl

" c:

III

::::l

Co

..•

III

Intraventricular Hemorrhage

Wilson Disease

III

(Left) Axial NECT shows subarachnoid & intraventricular hemorrhage related to a gunshot wound. Note hyperdensity in cerebral aqueduct (RighI) Axial T2WI MR shows hyperintensity without mass effect involving the dorsal pons & midbrain. The midbrain hyperintensity illustrates the" face of the giant panda" sign ~. Hyperintensity in the midbrain tegmentum, with sparing of red nuclei & lateral portion of the substantia nigra, is typical.

="!.

::::l

<

Ctl

~ :::!. Q. Ctl

en

Gliomatosis Cerebri (GC) (Left) Axial FUlIR MR shows acute

Wernicke

encephalopathy with hyperintensity in midbrain involving periaqueductal gray. Involved structures include mamillary bodies, thalami, cortex, & subcortical WM. (Right) Axial FUlIR MR shows hyperintensity in brainslem & media/temporal lobes, enlargement with preservation of underlying architecture. CC usually involves hemispheric WM. Involvement of brainslem is uncommon, 10-15% or

cases.

(Left) Axial T2WI MR shows symmet,;c signal abnormality in the periaqueductal gray Symmetric signal abnormality of deep gray structures & brainstem are characteristic of mitochondrial disorders. Leigh syndrome classically involves putamen, thalami, & periaqueductal gray. (Right) Sagittal T1 C+ MR shows

="!.

=-

enhancement

fornix

Aqueductal

in chiasm,

& aqueductE!:l. involvement

is

& juvenile Alexander disease & may cause hydrocephalus. common

in infantile

I 3 31

en c

FOURTH VENTRiClE MASS

a

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DIFFERENTIAL DIAGNOSIS Common • Medulloblastoma (PNET-MB) • Ependymoma • Pilocytic Astrocytoma • Brainstem Glioma, Pediatric Less Common • Subependymoma • Choroid Plexus Papilloma • Neurocysticercosis • Epidermoid Cyst • Hemangioblastoma • Metastasis, Intraventricular • Atypical Teratoid-Rhabdoid Tumor (ATRT) Rare but Important • "Trapped" 4th Ventricle • Ependymal Cyst • Dermoid Cyst • Lipoma • EncephaJocraniocutaneous Lipomatosis • Rosette-Forming Glioneuronal Tumor • Central eurocytoma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Age of patient is very helpful in differentiating lesions of the 4th ventricle • For many pediatric 4th ventricle masses, imaging of entire neuraxis prior to surgery is recommended (medulloblastoma, choroid plexus tumors, ATRT) • MR with contrast is best imaging modality • Sagittal images helpful to determine tumor origin (location in 4th ventricle)

I 3 32

Helpful Clues for Common Diagnoses • Medulloblastoma (PNET-MB) o Arises from vermis or roof of 4th ventricle (superior medullary velum) o Small round blue cells: Hyperdense on CT o 50% have CSF dissemination at diagnosis o Solid, enhancing mass within 4th ventricle o Hydrocephalus in > 90% • Ependymoma o Arises from floor of 4th ventricle o "Plastic" tumor squeezes out lateral recesses, foramen of Magendie o Intratumoral cysts, hemorrhage common o 2/3 are infratentorial within 4th ventricle

Heterogeneous, enhancing mass • Pllocytic Astrocytoma o Cyst with enhancing mural nodule o Typically cerebellar hemisphere rather than intraventricular o 60% are cerebellar; 30% optic nerve/chiasm • Brainstem Glioma, Pediatric o Intrinsic to brainstem, not 4th ventricle o May be dorsally exophytic, project posteriorly into 4th ventricle o

Helpful Clues for Less Common Diagnoses • Subependymoma o Inferior 4th ventricle, obex (60%) o Middle-aged, older adults o T2 hyperintense lobular mass o No or mild enhancement is typical • Choroid Plexus Papilloma o 40% involve 4th ventricle (posterior medullary velum), CPA, & foramina of Luschka o 4th ventricle common location in adults o Lateral ventricle more common in child o Lobular, vibrantly enhancing mass • Neurocysticercosis o Convexity subarachnoid spaces most common location o May involve cisterns> parenchyma> ventricles o Intraventricular cysts are often isolated, 4th ventricle most common o Imaging varies with stage, host response • Epidermoid Cyst o Congenital epithelial inclusion cyst o 90% intradural, primarily in basal cisterns • CPA: 40-50%; 4th ventricle 15-20% o Nonenhancing, lobular, extra-axial mass o Follows CSF on all sequences except FLAIR &DWI

• Hemangioblastoma o Intra-axial posterior fossa mass with cyst & enhancing mural nodule abutting pia o Associated with von Hippel-Lindau disease o 90-95% posterior fossa: 80% cerebellar hemispheres; 15% vermis, 5% other (medulla, 4th ventricle) o 7-10% of posterior fossa tumors 060% cyst & "mural" nodule; 40% solid • Metastasis, Intraventricular o Intraventricular metastases often involve choroid plexus

FOURTH VENTRiClE MASS

CIl

" c:

Gray-white junction lesions most common Primary tumor often known • Atypical Teratoid-Rhabdoid Tumor (ATRT) o 50% infratentorial, most off-midline; CPA, cerebellum &/or brainstem o Large mass with cysts &/or hemorrhage o Variable enhancement o Very young patients, usually < 3 years o May mimic medulloblastoma o o

Helpful Clues for Rare Diagnoses • "Trapped" 4th Ventricle o Related to extraventricular obstructive hydrocephalus (EVOH) or "communicating" hydrocephalus o EVOH: Obstruction distal to 4th ventricle outlet foramina o Etiologies include thickened meninges (often related to SAH, meningitis, CSF tumor seeding, venous obstruction, NPH) • Ependymal Cyst o Typically lateral ventricle: Body or atrium o 4th ventricle location rare o Follows CSF on all sequences • Dermoid Cyst o Commonly sellar/parasellar/frontonasal o May occur as primary 4th ventricle mass o Fat appearance with droplets in cisterns, sulci, ventricles if ruptured • Lipoma o Well-delineated lobulated extra-axial mass with fat intensity o 40-50% interhemispheric fissure

Sagittal T1 C+ MR shaws heterogeneous enhancement of this 4th ventIicufar medulloblastoma. Hydrocephalus & CSF seeding are characteristic of these WHO grade 4 tumors.

o Rarely involves 4th ventricle • Encephalocraniocutaneous Lipomatosis o Rare congenital neurocutaneous syndrome characterized by ipsilateral cranial, facial, ocular, & CNS anomalies o Unilateral hemispheric cerebral atrophy & ventriculomegaly in a child with ipsilateral alopecia overlying a scalp lipoma o CNS lipomas occur inconsistently • Rosette-Forming Glioneuronal Tumor o Newly described rare tumor of 4th ventricle, WHO grade 1 o Midline mass of 4th ventricle; may involve brainstem, vermis • Central Neurocytoma o "Bubbly" mass in frontal horn or body of lateral ventricle o 4th ventricle, extremely rare, < 1%

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<0

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Alternative Differential Approaches • 4th ventricle mass in a child o Medulloblastoma, ependymoma, pilocytic astrocytoma, brainstem glioma, ATRT • 4th ventricle mass in an adult o Metastasis, choroid plexus papilloma, subependymoma, hemangioblastoma • 4th ventricle mass, all ages: Neurocysticercosis, epidermoid, dermoid, "trapped" 4th ventricle

Sagittal T1 c+ MR shows an enhancing 4th ventIicular mass with extension through the foramen of Magendie. Note ventIicufar obstIuction with an enlarged cerebral aqueduct =::I & a dilated 3rd ventIide EI.

I 3 33

FOURTH VENTRiClE

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c

MASS

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Pilocytic Astrocytoma

Brainstem Glioma,

essential for characterization of a pediatric

posterior

fossa

mass. Detecting the relationship of the mass to the 41h ventricle is key. (Right) Sagitlal T2WI MR shows a focal glioma, localed in the dorsal pOnlomedullary junction wilh mild mass effect on the anterior 4th ventricle.

Choroid (Left) Sagittal T2WI MR shows a typical T2 hyperintense,

inferior

4th

ventricfe subependymoma E!lI. Lack of hydrocephalus is typical of subependymoma. These intraventricular masses are often asymptomatic. (Right) Sagittal T1 C+ MR shows a lobular, midline 4th ventricular mass with robust enhancement & hydrocephalus. Other 4th ventricular tumors would not demonstrate such strong enhancement. These tumors may be in the 4th ventricle or at the lateral recess.

Neurocysticercosis (Left) Sagi!!al T1 WI MR shows a cyst with a nodule within

the inFerior 4th

ventricle~.

The lesion

showed no enhancement, in

I 3 34

Pediatric

(Left) Sagitlal T I C+ MR shows a mixed cystic & solid posterior fossa mass with patchy enhancement of the tumor nodule. Note the 3rd ventricular obstruction. Multiplanar MR imaging is

keeping wilh the vesicular stage. The protoscolex is the viable larva within the thin-walled cyst visible on MR. (RighI) Axial FLAIR MR shows the 4th ventricular lesion & mild edema in the adjacent brain E!lI. As Ihis was a solitary lesion~ it was resected for diagnosis. Intraventricular NCC lesions are best seen on T7 & FLAIR MR.

Plexus Papilloma

FOURTH

,.-c:

VENTRICLE MASS

CJl

Ql

::l Co tll ...•

Hemangioblastoma

III

(Left) Axial TI C+ FS MR shows a non enhancing CSF-like mass expanding the 4th ventricle. The "scalloped" expansion of the 4th ventricle suggests epidermoid.

<

(1)

::J

...• ~ (1)

Vl

Most posterior

fossa epidermoids occur in the CPA cistern, rather than intraventricular. (Right) Sagittal TI C+ MR shows a cystic-appearing mass of the vermis with an enhancing nodule 81 adjacent 10 the compressed 4th ventricle !::ll. The mural nodule of hemangioblaslOma typically abuts a pial surface.

Atypical Teratoid-Rhabdoid (ATRT)

::l

:;0 (1)

to

o· ::J Vl

Tumor "Trapped" 4th Ventricle (Left) Sagillal TI C+ MR shows a typical posterior fossa ATRT as an off-midline mass with marked heterogeneity & enhancement. There is compression & displacement of the 4th ventricle. (Right) Sagillal TI C+ MR shows extraventricular obstructive hydrocephalus (EVOH) with enlargement of the 4th ventriclel causing displacement of the pons & medulla. EVOII is caused by blocked reabsorption of CSF through the arachnoid villi.

(Left) Axial N[CT shows a large, round CSF-like mass filling the 4th ventricle. Ependymal cysts are most common in the lateral ventricles & relatively rare in the 4th ventricle. (Right) Sagillal T I WI MR shows encephalocraniocutancous IipomalOsis, also known as Fishman syndrome, which may be characterized by extensive intracranial lipomas. There is a large lipoma

extending

into the

upper cervical canal!::ll & a prominent subcutaneous lipoma.

I 3 35

'"

c:

o

"BUBBLY-APPEARING"

INTRAVENTRICULAR

MASS

Ol Q)

0:::

DIFFERENTIAL DIAGNOSIS Common • Choroid Plexus Cysts

'" Q)

U ";::

C Q)

> c:

.... '"

a!

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less Common • Neurocysticercosis • Central Neurocytoma • Ependymoma • Subependymoma • Epidermoid Cyst • Cavernous Malformation • Ependymal Cyst Rare but Important • Choroid Plexus Papilloma • Choroid Plexus Carcinoma • Parasites, Miscellaneous • Astroblastoma

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Purely cystic intraventricular masses are usually benign o Xanthogranulomas> > ependymal or inflammatory cysts • Only truly common "bubbly-appearing" intraventricular masses = choroid plexus cysts (xanthogranulomas) Helpful Clues for Common Diagnoses • Choroid Plexus Cysts o Benign xanthogranulomas o Choroid plexus glomi, bilateral o Increased prevalence with age o Usually asymptomatic (rarely cause obstruction) o Histologically most are xanthogranulomas • Benign degenerative process • Typically FLAIR hyperintense • May restrict on DWI • Inhomogeneous enhancement common

I 3 36

Helpful Clues for less Common Diagnoses • Neurocysticercosis o Often show rim enhancement o Look for characteristic scolex, parenchymal/cisternal lesions o Small intraventricular cysts best seen on FLAIR • Central eurocytoma o Who grade II neoplasm o Younger age patients

•

•

•

• Nearly 1/2 occur in the 3rd decade • 75% between 2nd-4th decades o Location • Arises from septum pellucid urn or lateral ventricle wall • Anterior (near foramen of Monro), mid-body> > atrium, temporal horn • Less common: 3rd ventricle • Rare: Extraventricular central neurocytoma • 13% bilateral o Imaging • Cyst-like areas seen in 2/3 of cases • Moderate enhancement is typical • Punctate calcifications in up to 1/2 • Hemorrhage not uncommon Ependymoma o WHO grade II neoplasms o Arises from differentiated ependymal cells lining ventricles, central canal of the spinal cord o Mean age - 6 years o Location • 58% 4th ventricle • 42% lateral, 3rd ventricles • Less common: Extraventricular ependymoma o Imaging • Ca++ in 40-80% • Occasional intra tumoral hemorrhage yields blood-fluid levels • Contrast-enhancement varies; usually intense but spares the cyst-like regions • Extension beyond ventricular margins (paraventricular) not uncommon Subependymoma o Middle-aged, older adults o Most located within the 4th, frontal horn of lateral ventricles o Varied enhancement: None to intense, calcification, cyst formation may occur o Extension of a subependymoma beyond the ventricular margins is rare, unlike for ependymoma Epidermoid Cyst o DWl most specific: Restricted diffusion o FLAIR next most helpful sequence, showing "gray" CSF or incomplete CSF suppression Cavernous Malformation o Intraventricular location is uncommon

"BUBBLY-APPEARING" INTRAVENTRICULAR MASS o Imaging appearance like cavernous malformations elsewhere oGRE or SWI sequence helpful to assess for susceptibility due to blood products • Ependymal Cyst o Lacks enhancement o CSF signal all sequences (FLAIR most specific) Helpful Clues for Rare Diagnoses • Choroid Plexus Papilloma o Nearly half present in 1st decade o WHO grade I (carcinoma is WHO grade III) o Presentation with hydrocephalus common; can be due to mechanical obstruction and/or overproduction of CSF o Locations: Lateral ventricle most common site (50% of cases) > 4th ventricle (40%; most common in adults) > 3rd ventricle (5%) o Imaging • Cauliflower-like lobulated tumor, usually with moderate or intense enhancement • Hemorrhage, cyst formation may occur • Necrosis and/or parenchymal invasion suggest choroid plexus carcinoma • Flow voids common • Pure "cystic" variant may occur within ventricles, subarachnoid spaces • Astroblastoma o "Bubbly" appearance common o Parenchymal> > intraventricular

Choroid

Plexus Cysts

Axial T1 C+ MR shows multiple rim-enhancing cysts some with solid-appearing nodules 8l in atria of both laleral venlricles. llislologically these cysts are

=,

xanthogranulomas.

Other Essential Information • Enhancing intraventricular tumors may require MR neuraxis screening for drop metastasis, particularly when choroid plexus tumors and ependymoma are suspected • Nonenhancing cystic lesions with DWI restriction characteristic for epidermoid cysts • Neurocysticercosis can rarely mimic other intraventricular cysts, such as colloid cyst o Cryptococcal infection can present in a similar fashion to cysticercosis

SELECTED REFERENCES

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Bell JW et al: Neuroradiologic characteristics of astroblastoma. Neuroradiology. 49(3):203-9, 2007 Mathews M et al: Intraventricular cryptococcal cysts masquerading as racemose neurocysticercosis. Sueg eurol. 67(6):647-9,2007

o' :J (j)

Prayer D et al: MR imaging presentation of intracranial

disease associated with Langerhans cell histiocytosis. AJNR Am J Neuroradiol. 25(5):880-91, 2004 Koeller KK et al: From the archives of the AFII'. Cerebral intraventricular neoplasms: radiologic-pathologic correlation. Radiographies. 22(6):1473-505, 2002 Figarella-Branger 0, Soylemezoglu F, Kleihues 1', lIassounJ. cntral neurocytoma. In: Klcihues P, Cavenee W, eds. Pathology and genetics of tumours of the nervous system. Lyon, France: IARC, 107-109,2000 Takara K et al: Intraventricular, cystic, atypical meningioma. Neurol Med Chir (Tokyo). 37(11):856-60, 1997 Furie OM et al: Supratentorial ependymomas and subcpendymomas: cr and MR appearance. J Com put Assist Tomogr. 19(4):518-26,1995 Wichmann Wet al: Neuroradiology of central neurocytoma. Neuroradiology. 33(2):143-8, 1991 Morrison G et al: Intraventricular mass lesions. Radiology. 153(2):435-42, J984

Choroid

Plexus Cysts

Axial OWl MR in another case shows bilateral choroid plexus cysts that show diffusion restriction an occasional finding in this entity.

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(LeFt) Axial T2WI FS MR shows multiple cysts in the quadrigeminal cistern ~ and atrium of righllareral ventricle ~. Note trapped temporal horn '2>, (Courtesy E. Bravo, MOJ. (Right) Axial T2WI MR shows multiple "bubbly" intraventricular cysts in a patient with known NCe. (Courtesy B. Villarreal, MOJ.

=

Central Neurocytoma (Left) Coronal T2WI MR shows a typical MR case of central neurocytoma with a classic "bubbly"

-=

muJUcyslic appearance.

These tumors are typically attached to the septum pellucidum. (Right) Coronal Tl C+ MR in the same case as previous image shows patchy enhancement 82 within the partly cystic, "bubbly-appearing" mass

that arises from the septum

=

pellucidum.

(Left) Sagittal T2WI MR shows a large, "bubbly-appearing" 4th ventricle/cisterna magna mass in a 9 year old with a 2 month history of morning vomiting and worsening headaches. (Right) Sagittal T2WI MR shows a large, "bubbly-appearing" mixed cystic and solid 4th ventricular/cisterna magna mass in a 40 year old female with headaches.

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Incomplete suppression on FLAIR gives this epidermoid cyst a "cauliflower" or "bubbly" appearance. (Right) Axial T2WI MR shows a lobulated fluid signal intensity cyst in the 4th ventricle =:II. Although an arachnoid cyst is a possibility, the insinuating margins are more typical (or epidermoid.

Cavernous Malformation

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Cavernous Malformation (LeFt) Axial T1WI MR shows typical findings of a cavernous malformation in the atrium of the left lateral ventricle 1m. Note the classic mixed signal appearance, with intrinsic -f 1 shortening.

(Right) Axial T2WI MR in the

same case as previous image shows a mixed signal

=

with areas of high and low T2 signal, intensity

characteristic

of cavernous

malformation.

Choroid Plexus Papilloma

Choroid

Plexus Papilloma (Leh) Coronal T1WI MR in a 43 year old female with headaches shows a well-delineated inhomogeneously hypointense mass in the 4th ventricle (Right) Axial T2WI MR in the same case shows the "bubbly" appearance of mass caused by multiple small cysts =:II. Choroid plexus papilloma

cz.

was confirmed

at surgery.

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DIFFERENTIAL DIAGNOSIS Common • Normal Variant • Developmental Venous Anomaly • Multiple Sclerosis Less Common • Ventriculitis • Opportunistic Infection, AIDS • Neoplasm with CSF Seeding • Lymphoma, Primary CNS • Tuberculosis Rare but Important • Subependymal Venous Congestion o Sturge- Weber Syndrome o Thrombosis, Deep Cerebral Venous o Arteriovenous Malformation or Dural A-V Fistula • Vasculitis • Neurosarcoid • Langerhans Cell Histiocytosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Pre-operative neuraxis MR (imaging) recommended in patients suspected of having CSF seeding of tumor

I 3 40

Helpful Clues for Common Diagnoses • Normal Variant o Subependymal veins enhance normally & may be mistaken fur pathol9GY • Developmental VenousAnomaly o Enhancing "Medusa head" (dilated medullary white matter veins) o May have enlarged subependymal veins o Almost always unilateral, focal lesion o Angle of ventricle common location • Multiple Sclerosis o Common locations: Subependymal, peri ventricular, posterior fossa o Ovoid or round enhancing lesion with no significant mass effect o "Horseshoe" (incomplete ring enhancement) characteristic of demyelination o Tumefactive MS may mimic neoplasm, and enhancement may extend to ependyma

Helpful Clues for Less Common Diagnoses • Ventriculitis o Ventriculomegaly with fluid-debris level & enhancement characteristic o Associated DWI restriction typical o May complicate meningitis, abscess, or shunt • Opportunistic Infection, AIDS o CMV commonly causes ventriculitis o TB may cause ventriculitis o Toxoplasmosis may extend to ependyma & mimic lymphoma • Neoplasm with CSF Seeding o Many parenchymal tumors result in ependymal spread as they abut ventricular surfaces o Ependymal spread most common in childhood tumors: Medulloblastoma> ependymoma, pineal & choroid plexus tumors o Malignant gliomas in adults (GBM, anaplastic astrocytoma/ oligod en drogli oma) commonly spread along ependyma o Metastases from extra cranial primary: Breast & lung most common • Lymphoma, Primary CNS o Enhancing lesion(s) within basal ganglia, periventricular WM o Frequently abut, extend along ependymal surfaces o Often involves, crosses corpus callosum • Tuberculosis o Typically basal meningitis, may be complicated by ventriculitis o Dural & parenchymal disease common Helpful Clues for Rare Diagnoses • Sturge-Weber Syndrome o May cause subependymal venous congestion o Cortical Ca++, atrophy, & enlarged ipsilateral choroid plexus o UsuaJly a sporadic congenital malformation in which fetal cortical veins fail to develop normally • Thrombosis, Deep Cerebral Venous o Hyperdense internal cerebral veins on ECT o Usually affects bilateral internal cerebral veins and variably involves vein of Galen & straight sinus

EPENDYMAL

•

•

•

•

o Deep gray nuclei, internal capsule, medullary WM typically affected o Venous stasis in deep WM (medullary) veins seen as linear enhancing foci radiating outwards from ventricles o May cause subependymal venous congestion Arteriovenous Malformation or Dural A-V Fistula o AVM: Vascular malformation with arteriovenous shunting • Tightly packed mass of enlarged, enhancing vascular channels • May cause subependymal venous congestion o DAVF: Network of tiny vessels in wall of thrombosed dural venous sinus • Transverse sinus> cavernous sinus • May thrombose, resulting in venous infarct • May cause subependymal venous congestion Vasculitis o Linear enhancement along course of penetrating vessels o Enhancement often extends to ventricular margins o Extensive T2 hyperintense white matter common Neurosarcoid o Leptomeningeal & dural enhancing masses o May occur intraventricularly or along ependyma Langerhans Cell Histiocytosis

Developmental

Axial

n

Venous Anomaly

C+ MR shows an enlarged seplal vein

Rare subependymal involvement perivascular space infiltration o May affect choroid plexus o

by

Alternative Differential Approaches • Neoplasm with CSF seeding: Medulloblastoma, ependymoma, germinoma, GBM, metastases, lymphoma, anaplastic astrocytoma, anaplastic oligodendroglioma, choroid plexus tumors, pineoblastoma, leukemia • Ependymal enhancement in a child: Medulloblastoma, ependymoma, choroid plexus or pineal tumor, leukemia • Ependymal enhancement in an adult: High-grade gliomas, metastases, lymphoma, multiple sclerosis • All ages: Normal variant, developmental venous anomaly, ventriculitis

SELECTED 1. 2.

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REFERENCES

Fukui MB et al: CT and MR imaging features of pyogenic ventriculitis. AJNR Am J euroradiol. 22(8):1510-6,2001 Gomori JM et al: Leptomeningeal metastases: evaluation by gadolinium enhanced spinal magnetic resonance imaging. J eurooncol. 36(1):55-60, 1998

Multiple Sclerosis

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this pa(jent with a prominent leh centrum semiovale developmental venous anomaly ~. subependymal veins PJ:ll.

ENHANCEMENT

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Axial T7 C + M R shows mulliple foci of contrasl-enhancemenl PJ:ll along the subependymal region, characteristic

of multiple

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Infection, AIDS

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ventricular wall

a

enhancement characteristic of ventricu!Ws. This was due to right temporal lobe abscess rupture. Note associated meningeal enhancement along the pons =::I. (Right) Coronal

Tl C+ MR shows

multifocal ring E:I & nodular enhancing masses in this AIDS patient with toxoplasmosis. Note ependymal enhancement !:;:l in lesion adjacent to the

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ventricular

surface.

Neoplasm with (SF Seeding (Left) Axial T1 C+ FS MR shows metastatic seeding along the ependyma of the frontal horns of the lateral ventricles =::I in this child with medulloblastoma. Note also {ocal intraventricular lesion in the right frontal horn. Pre~operaliveimaging of the entire neuraxis is recommended in patients with medulloblastoma. (Rig"') Axial T I C+ FS MR shows thin linear enhancement along the ependymal margins of 4th ventricle due to tumoral seeding.

=

(Left) Axial T1 C+ MR shows a thick rind of enhancing

ependymal & subependymal tumor

common

germinoma,

which

in has a

propensity for CSF spread & brain invasion.

(Right)

Axial

T1 C+ MR shows multifocal linear enhancement in leukemic

I 3 42

infiltration

of

cerebral microvasculature & perivascular spaces. This pallern of "carcinomatous encephalitis II is a rare manifestation of systemic leukemia. Enhancement extends lo lhe venlricular margins.

Neoplasm with (SF Seeding

EPENDYMAL

ENHANCEMENT

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Tuberculosis (Left) Axial T1 C+ MR shows

ependyrnalenhancen1enl related to spread of lymphoma 1lli\1. Primary CNS lymphoma is classically located in the periventricular white maHer and abuts &/or

extends along the ependymal surfaces. Involvement of the leptomeninges or dura is more common

in sEcondary

lymphoma. (Right) Coronal T1 C+ MR shows subtle subependymal enhancement 1m in addilion to more classic basal meningeal enhancement

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Malformation A-V Fistula

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tuberculosis.

Arteriovenous

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or Dural Vasculitis (Left) Axial T 1 C+ MR shows enlarged subependymal & deep while maHer veins in this patient with dural AVF This ependymal enhancement is related to subependymal venous congestion. (Right) Sagittal T I C+ M/? shows linear enhancement that extends to the ependyma in granulomatous angiitis, a rare cause of vasculitis. Sarcoid, amyloid, & intravascular lymphoma could mimic this appearance.

=

=

(Left) Coronal T1 C+ MR shows septum pel/ueidum thickening {.'{enhancement Ea. There is a thickened infundibular stalk Illi\1 & septum pellucidum with subtle adjacent ependymal enhancement (Right) Axial T 1 C+ MR shows markedly enhancing masses in the suprasellar cistern choroid plexus of both lateral ventricfes and tentorial apex Ea. The enhancing choroid plexus masses extend to the ependymal surface, mimicking ependymal enhancement

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Common • Aging Brain, Normal • Encephalomalacia, General • Obstructive Hydrocephalus o Meningitis o Subarachnoid Hemorrhage, NOS o Intraventricular Hemorrhage • Cerebral Atrophy, NOS o Chronic Hypertensive Encephalopathy o Multiple Sclerosis o Alcoholic Encephalopathy o Radiation and Chemotherapy o Diffuse Axonal Injury (DAI) o Post-Meningitis o Drug Abuse Less Common • Alzheimer Dementia • Normal Pressure Hydrocephalus • Multi-Infarct Dementia • Frontotemporal Dementia Rare but Important • Choroid Plexus Papilloma • Megalencephaly Syndromes • Huntington Disease • Creutzfeldt-]akob Disease (C]D) • Inborn Errors of Metabolism (End-Stage)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Imaging most important to distinguish acutely obstructive causes from non-obstructive causes • Dementias best diagnosed clinically

I 3 44

Helpful Clues for Common Diagnoses • Aging Brain, Normal o Ventriculomegaly in proportion to sulci o Reflects atrophy from parenchymal loss • Encephalomalacia, General o Volume loss from many causes (prior stroke, trauma, surgery) o Focal, in areas of parenchymal tissue loss (with focal ventricular enlargement), or diffuse when global • Obstructive Hydrocephalus o Surgically emergent condition o Types of obstructive hydrocephalus

• Intraventricular obstructive hydrocephalus (IVOH) = "non-communicating hydrocephalus": Due to obstructed CSF at level of ventricles from focal mass effect • Extraventricular obstructive hydrocephalus (EVOH) = "communicating hydrocephalus": Due to obstructed CSF resorption at level of sulci, meninges/arachnoid granulations • CSF overproduction (choroid plexus tumors) o Meningitis • Mild hydrocephalus typical, may be earliest imaging finding (EVOH) • Leptomeningeal enhancement • Complications: Cerebritis/abscess, effusions, ischemia o Subarachnoid Hemorrhage, NOS • Impaired CSF resorption (EVOH) • Subarachnoid blood, often aneurysmal o Intraventricular Hemorrhage • Impaired CSF resorption (EVOH) • Ventricular blood, often related to trauma or AVM • Cerebral Atrophy, NOS o Chronic Hypertensive Encephalopathy • Brain parenchymal changes due to long-standing effects of untreated or poorly treated systemic hypertension • May result in vascular dementia • Diffuse white matter (WM) atrophy with low density or high T2 signal • May have hemorrhagic foci on GRE (basal ganglia, thalamus, cerebellum) o Multiple Sclerosis • Periventricular WM pattern of T2 hyperintensities ± enhancement • Often dramatic callosal volume loss & ventriculomegaly • Lesions generally lack mass effect o Alcoholic Encephalopathy • Chronic alcohol abuse results in symmetric lateral ventricle enlargement & superior vermian atrophy • Wernicke involvement: Mamillary bodies, medial thalami, hypothalamus, periaqueductal gray matter o Radiation and Chemotherapy • Late volume loss & diffuse T2 hyperintensity WM

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LARGEVENTRICLES

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o

o

• Spares subcortical "U" fibers Diffuse Axonal Injury (DAI) • DAI best seen on GRE, FLAIR,& DWI • Classic locations: Gray-white matter junctions, callosum, deep nuclei • Accompanied by late WM volume loss Post-Meningitis • Late WM volume loss diffusely • May have encephalomalacia related to abscess, ischemia Drug Abuse • Consider in young patients with ischemic or hemorrhagic strokes • Chronic: Volume loss

Helpful Clues for Less Common Diagnoses • Alzheimer Dementia o Parietal & temporal cortical atrophy with/disproportionate hippocampal volume loss is suggestive • Normal Pressure Hydrocephalus o Clinical triad of dementia, gait apraxia, & incontinence o Ventriculomegaly disproportionate to sulcal prominence, normal hippocampus o CSF flow studies can detect increased velocity • Multi-Infarct Dementia o Multifocal infarcts involving cortical gray matter, subcortical WM, & basal ganglia o Strokes of multiple ages & lacunes common o Often associated with arteriolosclerosis, WM hyperintensity

• Frontotemporal Dementia o Anterior frontotemporal atrophy with WM hyperintensity; "knife-like gyri"

III

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Helpful Clues for Rare Diagnoses • Choroid Plexus Papilloma o Intraventricular enhancing mass in child o Hydrocephalus due to obstruction &/or CSF overproduction • Megalencephaly Syndromes o Ventricular enlargement ipsilateral to enlarged hemisphere • Huntington Disease o Focal enlargement of frontal horns due to caudate atrophy • Creutzfeldt-jakob Disease (CJD) o Hyperintensity involving deep nuclei &/or cortex on DWI > FLAIR • Inborn Errors of Metabolism (End-Stage) o Chronic ventriculomegaly from parenchymal volume loss

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Alternative Differential Approaches • Ventriculomegaly may represent atrophy or "compensated" hydrocephalus • Compensated hydrocephalus: Compressed or small sulci, little/no transependymal CSF migration, relatively stable over time • Acute hydrocephalus: Small or compressed sulci, transependymal CSF migration (T2 hyperintensity along ventricular margins), ventricles enlarge over short time period o Acute obstruction usually requires urgent treatment

Obstructive Hydrocephalus

Axial FLAIR MR shows mild ventricular enlargement ~ in proportion to the mild sulcal enlargement in an elderly patient with expected atrophy, Note lack of

Coronal T2WI MR shows massive acute obstructive hydrocephalus, with ballooned ventricles & transependymal CSF migration due to a tectal

significant

glioma

a

white maller

disease.

m obstrucUng

a

the cerebral aqueduct.

I 3 45

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(Left) Sagittal T1 C+ MR shows a dilated 4th ventricle & extensive enhancement obliterating the basal cisterns & Filling the cisterna magna ~ Meningitis may be complicated by hydrocephalus, usually due to impaired CST resorption (EVOH). (Right) Axial NECT shows blood in the basal cisterns E1 & subarachnoid spaces ~. Note blood levels in the occipital horns & ventricular dilation due to acute ("communicating") hydrocephalus ([vOH).

m

Multiple Sclerosis (Left) Axial T2WI MR shows marked parenchymal volume loss evidenced by ventricular prominence 8lI & marked white matter volume foss. Note multiple while maller T2 hyperintense plaques related to the patient's MS. Marked corpus callosum atrophy is typical. (Right) Axial FLAIR MR shows lateral ventricle enlargement & diFFuseparenchymal volume 1055in a patient with chronic alcohol abuse. White matter disease is also noted, likely arteriolosclerosis.

=

Radiation and Chemotherapy (LeFt) Axial T2WI MR shows diFFusehyperintensity throughout perivenlricular white matter sparing the subcortical U-Fibers & corpus callosum, in this young patient who underwent radiation & chemotherapy. (Right) Coronal T2WI MR shows marked venlriculomegaly in a patient with a history of coccidioides meningitis. Lack of transependymal CSF migration suggests the obstruction is likely chronic ("compensated") or low grade.

=

=

I 3 46

Post-Meningitis

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(Lefl) Axial T2WI MR shows multiple high signal foci in the basal ganglia !::ill & white maller caused by vasculitis related to drug abuse. In young patients with ischemia, drug use should be considered. Street drugs such as amphetamines may cause chemical vasculitis with secondary infarcts. (Right) Axial NECT shows multiple

hypoinlensilies

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with

associated volume 1055 consistent with prior territorial

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infarctions.

Basal ganglia lacunes are also typical.

Frontotemporal Dementia

Choroid Plexus Papilloma (Left) Axial NECT shows enlargement of the frontal horns with "knife-like" gyri 8l characteristic of Pick disease. Note relalive sparing of the parietal & occipital lobes. Selective frontal & temporal atrophy is characteristic. (Right) Axial Tl C+ MR shows venlriculomegaly !::ill due to an enhancing trigone mass ~ without obstruction. Ventriculomegaly is related to overproduction of CSF that outpaces the ability of arachnoid granulations to resorb CSF.

Huntington Disease (Left) Axial CECT shows an enlarged right hemisphere & characteristic ipsilateral enlarged deformed lateral ventricle in megalencephaly. (Right) Axial TlWI MR shows enlargement of both frontal horns, with 1055of the

-=

normal concave appearance of the lateral ventricular

margins, consistent with caudate head atrophy 1J::l.

I 3 47

SMALLVENTRICLES

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DIFFERENTIAL DIAGNOSIS Common • Normal Variant (Young Brain) • CSF Shunts and Complications • Cerebral Edema, Traumatic • Herniation Syndromes, Intracranial Less Common • Encephalitis • Intracranial • Intracranial • Intracranial • HIE, NOS • Meningitis

(Miscellaneous) Hypotension Hypertension, Idiopathic Hypertension, Secondary

Rare but Important • Brain Death • Inborn Errors of Metabolism (Acute Presentation)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Clinical presenting features usually help define the category of disease in question Helpful Clues for Common Diagnoses • Normal Variant (Young Brain) o Ventricles in children, young adults can normally appear quite small • CSF Shunts and Complications o CSF diversion • ± Reduced ventricular compliance o Compliance changes caused by • Ependymal scar/adhesions

CSF Shunts and Complications

I 3 48

=

Axial NECT shows small ventricles & indeterminate shunt position 61. SymptomaUc ventJicular collapse is known as "s/il·like venlfic1e syndrome" & suggests

overshunting.

o Cause shunted ventricle to collapse • Cerebral Edema, Traumatic o Low density parenchyma with sulcal & ventricular effacement o Hyperdense cerebellum, "reversal sign" • Herniation Syndromes, Intracranial o Ventricular effacement common

Helpful Clues for Less Common Diagnoses • Encephalitis (Miscellaneous) o White matter T2 hyperintensity & edema o Mild restriction on DWI common • Intracranial Hypotension o "Slumping" midbrain, acquired tonsillar herniation/ectopia, enhancing dura • Intracranial Hypertension, Idiopathic o "Pseudotumor cerebri" o Dilated optic nerve sheaths, basal cisterns effaced, small ventricles • Intracranial Hypertension, Secondary o Etiology: Any causes of high intracranial pressure or diffuse edema: Trauma, venous outflow obstruction, anoxic or metabolic encephalopathy, mass, brain death • HIE, NOS o Global anoxic/ischemic event results in DWI changes • Basal ganglia> diffuse cortex bright • Diffuse white matter restriction (may be subacute manifestation) o DWI abnormalities evolve slower than thromboembolic infarction • Meningitis o Mild hydrocephalus> > > small ventricles

Cerebral

Edema, Traumatic

=-

Axial NECT shows hyperdense foci of DAI which is commonly associated with tJaumaUc cerebral edema. Note sulcal & ventricular effacement ffi Loss of gray-while differentiation is common.

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Herniation

Syndromes, Intracranial

Encephalitis

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(Miscellaneous) (Left) Axial NECT shows low density subacute infarcts in the cerebellar hemispheres. Basal cisterns are effaced as is the 4th ventricle m in this patient with transtentoriaf herniation.

:l

=

Herniation

syndromes

typically result from trauma, ischemia, or mass. (Right) Axial fLAIR MR shows near confluent T2 hyperintensity in the deep white mailer & small ventricles Ell related to mild mass effect from the encephalitis.

=:J

(Left) Axial T7 C+ MR shows symmetric small ventricles and smooth diffuse linear pachymeningealthickening and enhancement ~. (Right) Coronal T1WI MR in young adult female with headaches, papilledema shows very small lateral ventricles EB Superficial sulci ~ also look somewhat less prominent than normal. Pituitary gland is normal for a young menstruating female.

=

(Left) Axial PO FSEMR shows enlarged bilateral hyperintense deep nuclei & small ventricles ~ from mass effect in HIE. Cortical hyperintensity is less prominent than on OWl (not

=:J

shown)

except for more

advanced bilateral occipiwl involvement liB (Right) Axial T2WI MR shows diffuse acute brain swelling in maple syrup urine disease & small ventricles due to subacute edema of deep white mailer thalami and internal capsules.

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DIFFERENTIAL DIAGNOSIS Common • Normal Variant • Extrinsic Mass Effect • Encephalomalacia, General • Intraventricular Hemorrhage • Herniation Syndromes, Intracranial • Surgical Defects • Obstructive Hydrocephalus • Choroid Plexus Cyst Less Common • Ventriculitis • CSF Shunts and Complications • Meningioma • Choroid Plexus Papilloma • Neurocysticercosis Rare but Important • Intraventricular Synechiae/Adhesions • Choroid Plexus Carcinoma • Ependymal Cyst • Dyke-Davidoff-Masson • Hemimegalencephaly

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Asymmetric lateral ventricles are most commonly seen as a normal variant

I 3 50

Helpful Clues for Common Diagnoses • Normal Variant o Asymmetric lateral ventricles seen in 5-10% of normal population o Asymmetry mild-moderate, left> right o Septum may be displaced across the midline o 0 associated mass effect, herniation, or parenchymal atrophy o Must exclude underlying mass or obstructing lesion • Extrinsic Mass Effect o Etiologies include mass, hemorrhage, infarct, infection o Mass can cause ventricular deformity, subfalcine herniation • Encephalomalacia, General o Parenchymal loss results in compensatory ventricular enlargement o Common etiologies include chronic infarct, trauma, surgery

• Intraventricular Hemorrhage o Involved ventricle may dilate early from mass effect o Chronic dilation may be due to scarring from adhesions o Etiologies include trauma, AVM, basal ganglia hemorrhage • Herniation Syndromes, Intracranial o Subfalcine herniation: Cingulate gyrus herniates under falx • Ipsilateral lateral ventricle compressed • Foramen of Monro obstructs, causes contralateral lateral ventricle enlargement o Unilateral descending transtentorial herniation (uncal): Herniation of medial temporal lobe inferiorly • Contralateral temporal horn becomes entrapped & enlarges o Entrapped ventricle: Typically temporal horn, by extrinsic mass effect • Surgical Defects o Look for calvarial defect or "tract" o Typically related to resection of mass o Ventricle enlarged unilateral to defect • Obstructive Hydrocephalus o Typically acquired & bilateral o May be unilateral if shunt complication or obstructing tumor is cause o Rare: Colloid cyst may obstruct unilateral foramen of Monro & cause unilateral ventriculomegaly • Choroid Plexus Cyst o Nonneoplastic, noninflammatory cyst of the choroid plexus o Common incidental finding in older patients (40% prevalence) o Typically bilateral, may be unilateral & enlarge lateral ventricle Helpful Clues for Less Common Diagnoses • Ventriculitis o Ventriculomegaly with debris level, enhancing ependyma o May affect lateral ventricles asymmetrically, particularly if related to shunt placement or abscess rupture • CSF Shunts and Complications o Common complications include shunt obstruction or breakage, infection, overdrainage

ASYMMETRIC LATERALVENTRICLES Asymmetric ventricles may result from overdrainage or underdrainage of an "isolated" ventricle • Meningioma o Intraventricular meningioma rare, typically left lateral ventricle o Associated with choroid plexus o Smooth enhancing intraventricular mass • Choroid Plexus Papilloma o Enhancing, lobulated intraventricular mass in a child o 50% in lateral ventricle atrium, left> right o May obstruct CSF flow or overproduce CSF o May have CSF spread of tumor • Neurocysticercosis o Intraventricular disease uncommon o Rarely may obstruct unilateral foramen of Monro & cause asymmetric lateral ventricle o Cyst with "dot" representing scolex characteristic o Tl & FLAIR best show intraventricular cysts o

Helpful Clues for Rare Diagnoses • Intraventricular Synechiae/Adhesions o May be congenital or acquired (prior bleed, infection, tumor) o Look for enhancing septae, intraventricular cysts within ventricle • Choroid Plexus Carcinoma o Enhancing intraventricular mass & ependymal invasion in young child o CSF seeding common

• Ependymal Cyst o Nonenhancing thin-walled cyst with CSF density/intensity o Lateral ventricle most common location • Dyke-Davidoff-Masson o Antenatal unilateral hemispheric infarction causes cerebral hemiatrophy o Ipsilateral calvarial thickening & hyperpneumatized frontal sinuses, temporal bones o Dilated ventricle from volume loss is ipsilateral to small hemisphere • Hemimegalencephaly o Unilateral hemispheric enlargement o Dilated, usually dysmorphic ventricle ipsilateral to enlarged hemisphere o Ipsilateral extra calvarial soft tissues may be larger

acrossmidline~.

::::l

a.

ro ...• III

::::l

;:0 C1> <0

o' ::::l en

Other Essential Information • High resolution "MR cisternography": CISS, balanced FFE, FIESTA o May detect small septations or arachnoid membranes causing obstruction • Cine CSF flow study may help detect physiologic flow obstruction from arachnoid webs or membranes o May assess adequacy of drainage procedures

Extrinsic Mass Effect

Normal Variant

Axial T2WI MR shows asymmetrically large right ventricular system I:] representing a normal variant. Note mild displacement of the septum pellucidum

III

Axial T1 horn lID primary common

C+ MR shows compression of the left frontal by a large periventricular enhancing mass !Ill eNS lymphoma. Extrinsic mass effect is a cause of ventricular asymmetry.

I 3 51

en c

ASYMMETRIC

o

lATERAL VENTRiClES

Cl Q)

0::

~ ~

.!l1 ()

Encephalomalacia,

·C

C Q) > ·C Q)

0..

en

Q)

U

·C

C Q)

> C

III

~

en

"C

c

III

General

Intraventricular

Hemorrhage

(Left) Axial T2WI MR shows chronic MCA ischemia as encephalomalacia with gliotic hyperintense borders PJ:lI. The adjacent sulci are prominent and there is enlargement of the ipsilateral lateral ventricle SI related to volume loss. (Right) Axial NECT shows a basal ganglia hypertensive hemorrhage with intraventricular extension m. Associated midline shift results in dilation of the contralateral ventricles from foramen

=

of Monro

=

obstruction.

Surgical Defects (Left) Coronal T1 C+ MR shows a right hemispheric subacute subdural hematoma causing subfalcine PJ:lI& uncal SI herniation. Mass effect compresses the right frontal horn. The left ventricle ~ is enlarged from foramen of Monro obstruction. (Rig"') Axial T2WI MR shows widening of right foramen of Monro seplum pellucidum deviation & enlarged right lateral ventricle eJ in this tuberous sclerosis patient with remole tumor resection.

=

Obstructive (Left) Axial NECT shows marked enlargement of the left lateral ventricle with bowing of seplum peflucidum across midline & transependymal CSF migration EI indicating acute obstruction. Findings were related to a small atrial diverticulum. (Right) Axial T2WI MR shows a medial atrial diverticulum a rare complication of severe hydrocephalus. CSF pouch herniates inferomedially through tentorial incisura.

=

=.

I 3 52

Hydrocephalus

ASYMMETRIC

LATERAL VENTRiClES III

:J Co

..• OJ III

(Left) Axial T' C+ MR shows a lobulated, nonenhancing mass =:I in the lateral ventricle atrium, a choroid plexus xanthogranuloma. This degenerative cyst of the choroid plexus is often found incidentally in older patients. (Right) Axial T7 C+ MR shows ventriculitis with asymmetric lateral ventricles related to a temporal lobe abscess rupture &

=

meningitis

rz.

:J

<

(tl

;:; ::!. ()

roen

;:0

Note

ventriculomegaly & ventricular wall enhancement characteristic of ventriculitis.

a

(tl

<0

o :::J en

(Left) Axial T2WI MR shows marked

enlargement

of the

isolated right lateral ventricle with transependymal flow of CSF p:;Jl indicating acute obstruction.

Note left shunt

=:I & completely decompressed left lateral ventricle. (Right) Axial T7 C+ MR shows enhancement within the mass in the atrium of the lateral ventricle =:I with encysted asymmetrically larger left lateral ventricle.

(Left) Axial T7 C+ FS MR shows a large mass in atrium of right lateral ventricle p:;Jl with trapped, encysted occipital horn 81. Ependymal enhancement represents tumor spread from choroidal metastasis. (Right) Axial FLAIR MR shows a cyst enlarging the left lateral ventricle with signal intensity isoinlens€ La CSF =:I. There was no enhancement of the cyst wall, typical of ependymal cyst.

I 3 53

IRREGULAR LATERALVENTRICLES

CIl C

o Ol C1l

a:::

Deformity is chronic Overlying skull or scalp also shows defect Peri ventricular Leukomalacia o "Wavy" margins or undulating lateral ventricular contours typical o Cysts or ill-defined T2 hyperintensity in periventricular white matter (WM) o Colpocephaly common & reflects predominant posterior WM loss Cerebral Infarction, Chronic o Vascular territory wedge-shaped area of encephalomalacia o Results in compensatory or "ex vacuo" dilation of the regional ventricle, due to volume loss Porencephalic Cyst o Cystic space in brain parenchyma with enlarged adjacent ventricle, may communicate with ventricle o Cyst may cause mild mass effect (from CSF pulsations) Chiari 2 o Pointed anterior horns, colpocephaly o Small posterior fossa, tecta I "beaking", downward herniation of cerebellar tissue through foramen magnum o Associated with a lumbar myelomeningocele o

DIFFERENTIAL DIAGNOSIS

o

CIl

C1l

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>

::::I

-"

l/)

Common • CSF Shunts and Complications • Surgical Defects • Peri ventricular Leukomalacia • Cerebral Infarction, Chronic • Porencephalic Cyst • Chiari 2 Less Common • Heterotopic Gray Matter • Tuberous Sclerosis Complex • Metastases, Intracranial, Other • Intraventricular Webs or Adhesions • CMV, Congenital • Schizencephaly

•

•

•

Rare but Important • Hemimegalencephaly • Holoprosencephaly • Holoprosencephaly Variants •

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Irregular ventricles may be the result of obstruction, chronic volume loss &/or congenital deformities o Obstruction: Mass effect, "ballooned" appearing ventricles, & transependymal CSF migration o Volume loss: Ventricle irregularity with brain parenchymal loss o Congenital: Look for associated findings (colpocephaly, subependymal nodules) • Ventricular deformities may become permanent despite relief of obstruction, due to parenchymal atrophy or acquired ventricular non-compliance • Enhancement may help differentiate etiologies

I 3 54

Helpful Clues for Common Diagnoses • CSF Shunts and Complications o Common complications include shunt obstruction/breakage, infection, overdrainage o Acquired ventricular non-compliance may result in ventricle deformity • Surgical Defects o Often evident from prior shunt tract or burr hole

Helpful Clues for Less Common Diagnoses • Heterotopic Gray Matter o Subependymal nodules follow gray matter signal & do not enhance o May be seen with epilepsy or incidental • Tuberous Sclerosis Complex o Subependymal nodules lining the ventricles characteristic • Mostly along striothalamic groove • Calcify with increasing age o Cortical & subcortical tubers are usually multifocal ± mild mass effect • Tubers are most easily seen on FLAIR • Rarely tubers may calcify or enhance o Enhancing mass at foramen of Monro = subependymal giant cell astrocytoma • Metastases, Intracranial, Other o CSF seeding of primary CNS tumors, lymphoma or systemic malignancy may cause irregular ventricles o May result in ventricular nodules which can deform the ventricles • Intraventricular Webs or Adhesions

IRREGULAR LATERAL VENTRiClES

CJl ;><"

r::

May be congenital or acquired (prior hemorrhage, infection or tumor) o Contours of ventricles may be rounded or balloon-like due to obstructive symptoms o Contrast ventriculography or cine CSF can be helpful to assess for evidence of physiological flow obstruction • CMV, Congenital o White matter volume loss o Periventricular calcifications are common o Polymicrogyria & cortical malformations may be seen • Schizencephaly o Outward "dimpling" of lateral ventricle suggests schizencephaly o Look for gray matter lining the CSF cleft o

Helpful Clues for Rare Diagnoses

• Hemimegalencephaly o Hamartomatous overgrowth of part/all of a hemisphere o Lateral ventricle ipsilateral to enlarged hemisphere is usually bizarre-shaped & typically enlarged • Holoprosencephaly o Congenital structural forebrain anomalies defined by degree of frontal lobe fusion o All types have absent septum pellucidum & frontal lobe fusion anomaly o Alobar: Monoventricle, often incompletely covered posteriorly by brain ("dorsal cyst") o Semi/obar: Anterior horns absent, partial occipital & temporal horns

Lobar: Anterior lateral ventricle may be deficient • Holoprosencephaly Variants o Middle interhemispheric (MIH) variant of holoprosencephaly o MIH: 25% hyperintense dorsal cyst, obstructs third ventricle o

III

::::l

a.

..,

llJ III

::::l

<

CD

~ :0. ~ CD

U>

Alternative

Differential

Approaches

• Tumors resulting in irregular ventricles are typically related to CSF dissemination • Adult tumors with CSF spread: GBM or other malignant gliomas • Pediatric tumors with CSF spread: Medulloblastoma, ependymoma, choroid plexus papilloma, pineal tumors • Systemic malignancies with CSF spread: Lymphoma, breast or lung cancers • Gadolinium studies can differentiate among causes of ependymal nodules • Nonenhancing subependymal nodules may represent gray matter heterotopia or TSC nodules o Gray matter heterotopias follow gray matter signal/density o TSC nodules follow white matter signal or are calcified • Enhancing nodules suggest ependymal tumor seeding

CSF Shunts and Complications

;;0 CD CO

o· ::::l

U>

Surgical Defects

I

=

left lateral ventricle, which remains irregularly enlarged

Axial T2WI MR shows irregular enlargement of the left occipital horn due to left temporal and occipital surgical defect & encephalomalacia from tumor removal

PJ:J.

in this localion.

Axial NECT shows a right frontal ventricular drain that

traverses the right ventricle but is not decompressing the

3 55

IRREGULAR LATERAL VENTRiClES

'"c

.Q C> Q)

0::: Periventricular leukomalacia (Left) Axial T2WI MR shows classic "wavy" or undulating contours

'"

Q)

u ·C C Q)

> C 01

...

al "C

c

01

of the lateral

=

ventricles in addition to colpocephaly (enlargement of the posterior portions of lateral ventricles). Colpocephaly refleclS the predominantly posterior volume 1055. (Right) Axial NECT shows irregular enlargement of the left frontal horn 81 due 10 focal regional parenchymal volume los5 in this patient with remote

MCA

infarct.

(Left) Axial CECT shows a low density outpouching from the right lateral ventricle 1::1. While a thin rim of cortex seems intact, the cyst nearly reaches brain surface & can be considered a porencephalic dilation or porencephalic lateral ventricle cyst. (Right) Axial NfCTshowsirregu~r~ dilated occipital horns 1::1 with interdigitation of parietal & occipital parenchyma across midline PJ:ll due 10 a falx deficiency.

(Left) Axial T1 WI FS MR shows multifocal nodularity along ependymal margins of both lateral ventricles 1:12. These nodules follow gray matter signal on all sequences & do not enhance or change over time. (Right) Axial T2WI MR shows multiple calcified subependymalnodules (SEN) 1:12 lining ventricles. Note also subcortical tubers PJ:ll. SEN calcify much more commonly than

cortical/subcortical tubers.

I 3 56

Approximately 50% SfN are calcified by 10 years of age.

IRREGULAR lATERAL VENTRiClES

CIl

""c: Ql

:J Co

tll .., Ql

CMV, Congenital (Left) Axial T2WI MR shows

:J

near complete coating of the ependymal lining of both lateral

=

venlricles

with tumor

nodules due to metastatic seeding of anaplastic oligodendroglioma. (Right) Axial NECT shows periventricuJar calcification ~ particularly along the

cauda-striatal groove in the context of microcephaly & developmental delay. This strongly suggests congenital CMV inFection. Note smooth ventricular margins, unlike calciFied nodules in TSC complex.

(Left) Axial NECT shows Focal outpouchings of CSF From both lateral ventricles with a CSF cleFt extending From lateral ventricles to the subpial surface. The "pial-ependymal seam" is gray matter-lined. (Right) Axial T2WI MR shows cortical dysplasia & open-lip schizencephaly Schizencephaly is closed-lip with a Fusedgray matter lined pial-ependymal seam or open-lip with large, gray matter-lined & Fluid-Filled CSF cleFts.

=

=.

(Left) Axial T2WI MR shows enlargement of leFt cerebral hemisphere accompanied by an irregular ipsilateral ventricle The body of the leFt hemispheric white matter is bulky. Note leFt Fornix ~ overgrowth. (Right) Axial TlWI MR shows a large

=.

/I

horseshoe*shaped"

monovenlricle with fused basal ganglia. There is no interhemispheric fissure & no identiFiable lobulation or formation of ventricular horns in this a/abar holoprosencephaly patient.

I 3 57

PERIVENTRICULAR

IJ)

c:

o

ENHANCING

LESIONS

Cl Q)

0::

DIFFERENTIAL DIAGNOSIS Common • Multiple Sclerosis • ADEM • Lymphoma, Primary CNS

IJ)

Q)

U 'C

C Q)

> c: III

'm "C

c:

III

Less Common • Glioblastoma Multiforme • Abscess • Toxoplasmosis, Acquired • Germinoma • Metastases, Parenchymal • Vasculitis • Lyme Disease • Ependymoma Rare but Important • Leukemia • Susac Syndrome • Alexander Disease • Ependymal/Subependymal

o May be identical to MS • Lymphoma, Primary CNS o Enhancing periventricular WM or BG mass o Often extend along ependymal surfaces o Often crosses corpus callosum o Solid appearing mass with low T2 signal, mild DWI restriction o Hyperdense on CT

Helpful Clues for Less Common Diagnoses • Glioblastoma Multiforme o Peripherally enhancing WM mass with central necrosis o Surrounding T2 hyperintensity & significant mass effect common o Often crosses corpus callosum • Abscess o Ring enhancing mass in peri ventricular

WM Veins (Mimic) •

ESSENTIAL INFORMATION

•

•

•

•

I 3 58

Smooth, thin, linear enhancement DWI restriction characteristic Toxoplasmosis, Acquired o Multiple WM & BG ring enhancing masses o May show "target" sign o DWJ restriction variable o Typically seen in HIV patients Germinoma o Enhancing midline mass (pineal, suprasellar) typical o Occurs in BG or thalamus 5-10% o Hyperdense on CT o CSF spread common Metastases, Parenchymal o Gray-white junctions & multiple enhancing lesions typical o May occur in periventricular WM o Primary tumor often known Vasculitis o Irregularities, stenosis & vascular occlusions o Multifocal cortical/subcortical & BG T2 hyperintensities; DWI restriction if acute o Patchy enhancement typical o Angiography remains gold standard for diagnosis Lyme Disease o Periventricular T2 hyperintensities + enhancement in patient with skin rash & flu-like illness o Cranial nerve enhancement may occur • eN? often involved o May be identical to MS o o

PERIVENTRICULAR • Ependymoma o Majority (2/3) infra tentorial • 4th ventricle in a child • ± Extension through lateral recesses into CPA cisterns o 1/3 are supratentorial • Most are extraventricular • Typically periventricular WM o Heterogeneous enhancing mass o 50% are calcified o Cysts, hemorrhage common Helpful Clues for Rare Diagnoses

• Leukemia o Typically involves dura o May see along penetrating vessels or ependyma o Enhancing mass(es) in a child • Susac Syndrome o Clinical triad: Encephalopathy, retinal artery occlusions, hearing loss o Corpus callosum, BG, posterior fossa lesions o May be identical to MS • Alexander Disease o Diffuse symmetric bifrontal WM signal abnormality & enhancement o ear total lack of myelin o Infant with macrocephaly, seizures, developmental delay • Ependymal/Subependymal Veins (Mimic) o Normal periventricular venous structures may become engorged with various pathologies

Multiple Sclerosis

Axial Tl C+ MR shows numerous enhancing MS plaques in the periventricular ~ & subcortical white matter. Note typical lack of mass effect. ADEM & Lyme disease may be idenUcal.

ENHANCING

LESIONS

• Venous thrombosis, vascular malformations (AVM, DVA) Alternative

Differential

Approaches

• Mass involving corpus callosum: GBM, lymphoma, MS, ADEM • Mass in immunocompromised patient: Lymphoma, abscess, toxoplasmosis, metastases • Single enhancing mass: MS (tumefactive), ADEM (tumefactive), lymphoma, GBM, abscess, germinoma, ependymoma • Multiple enhancing masses: MS, ADEM, lymphoma, abscess, toxoplasmosis, metastases, vasculitis, Susac syndrome

ell

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:J

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(f)

;:0 CD to

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(f)

SELECTED REFERENCES 1.

2.

3.

Lucchinetti CF et al: Clinical and radiographic spectrum of pathologically confirmed tumefactive multiple sclerosis. Brain. 131(Pt 7):1759-75, 2008 Hunt MA et al: Distinguishing primary central nervous system lymphoma from other central nervous system diseases: a neurosurgical perspective on diagnostic dilemmas and approaches. Neurosurg Focus. 21 (5):E3, 2006 Do TH et al: Susac syndrome: report of four cases and review of the literature. AJNR Am J Neuroradiol. 25(3):382-8, 2004

Multiple Sclerosis

Axial T1 C+ MR shows characteristic tumefaClive MS plaque with i((egula, thick, partial ring enhancement & mass effect These lesions may cross the corpus callosum & mimic tumors.

=.

I 3 59

PERIVENTRICULAR

(/)

c .Q

ENHANCING

LESIONS

Ol
0:::

ADEM

lymphoma,

Primary eNS

(Left) Coronal T1 C+ MR shows numerous foci of enhancement in the subcortical & perivenlricular white matter. enhancing

Fuzzy

margins are

typical for demyelination. ADEM typically follows an infection

or vaccination.

(Right) Axial T1 C+ MR

shows homogeneous enhancement perivenlricular

within

multiple

white maller

~ foci. Lack of significant surrounding T2 abnormality (not shown) & mild mass & corpus callosum involvement is common.

Glioblastoma

Multiforme

(Leh) Axial T1 C+ FS MR shows a large heterogeneously enhancing occipital lobe mass with central necrosis. Note extension across the splenium of the corpus ca/Josum B characteristic of glioblastoma multiforme. (Right) Axial T1 C+ FS MR shows a ring enhancing mass ~ in the left frontal lobe. Thin walled enhancement is typical of abscess; note impending intraventricular ruplUre~.

Germinoma (Left) Coronal T1 C+ MR shows multifocal masses with ring-enhancement

=.

Nodular enhancement is also frequently seen EJ. Toxoplasmosis often lacks restricted

diffusion

on MR,

unlike most abscesses. (Right) Coronal T1 C+ MR shows a large mixed solid & cystic heterogeneously enhancing mass involving the right basal ganglia ~. Up to 10% of CNS germinomas

basal ganglia.

I 3 60

arise within

the

PERIVENTRICUlAR

ENHANCING

en

lESIONS

r:: " Ql

::l 0OJ ., Ql

(Left) Axial T7 C+ MR shows enhancing lesions in the periventricuJar

::l

while maller

~ in this patient with a history of breast cancer. (Right) Axial T7 C+ MR shows patchy mullifocal enhancement consistent with

subacute inFarcts in this patient with lupus vasculitis. Vasculitis is often in the cortical & subcortical white matter, although basal ganglia involvement is common.

Associated

OWl

restriction may be seen.

;0 CD <0

o

::l

'" Lyme Disease

Ependymoma (Left) Axial T7 C+ MR shows multifocal punctate foci of

=

perivenlricular

enhancement

with associated T2 hyperintensity (not shown) without significant mass effect This pattern mimics MS and ADEM. (Right) Axial NECT shows a left perivenlricular enhancing mass with small cystic areas E1 that are commonly

=

present. [pendymomas more commonly are in or near the 4th ventricle but may be supratentorial (1/3 of cases). Calcifications

are seen in

50%.

Susac Syndrome

Alexander

Disease (Left) Sagittal FlAIR MR shows multiple hyperintense lesions in the corpus callosum, typical for Susac syndrome & MS. Enhanced scans typically show leptomeningeal enhancement. (Right) Axial T7 C+ MR shows characteristic near-tota/lack of while matter myelination & striking enhancement of the deep peri ventricular white matter These patients usually present with a large head.

=

a

I 3 61

en c

INTRAVENTRICULARCAlCIFICATlON(S)

.Q C) Q)

0:: ~

DIFFERENTIAL DIAGNOSIS

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C Q)

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C Q)

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:::J .>0:

C/)

Common • Physiologic Calcification, Choroid Plexus • Choroid Plexus Cyst • Neurocysticercosis • Neurofibromatosis Type 2 • Tuberous Sclerosis Complex less Common • Meningioma • Ependymoma • Intraventricular Hemorrhage (Mimic) • Choroid Plexus Papilloma • Subependymal Giant Cell Astrocytoma • Subependymoma • Central Neurocytoma • Cavernous Malformation • TORCH, General (Mimic) Rare but Important • Medulloblastoma (PNET-MB) • Choroid Plexus Carcinoma • Craniopharyngioma

ESSENTIAL INFORMATION

I 3 62

• Nodular calcified (healed) stage: Small, Ca++ nodules o Typically subarachnoid spaces; may involve cisterns> parenchyma> ventricles o Intraventricular cysts are often isolated; 4th ventricle most common o Most common cause of cerebral Ca++ under 30 years • Neurofibromatosis Type 2 o Nonneoplastic cerebral Ca++ is uncommon manifestation o Extensive choroid plexus Ca++ > cortical surface Ca++ > ventricular lining Ca++ • Tuberous Sclerosis Complex o Ca++ subependymal nodules (SEN), 98% of patients • Along caudothalamic groove> atrial> > temporal • 30-80% of SEN enhance, best seen on MR o Cortical/subcortical tubers, WM lesions 70-95% Helpful Clues for less Common Diagnoses • Meningioma o Calcified (20-25%): Diffuse, focal, sand-like, sunburst, globular, rim o Approximately 1% are intraventricular o Most common in left lateral ventricle • Ependymoma o Soft or "plastic" tumor: Squeezes out through 4th ventricle foramina o Ca++ common (50%) o 2/3rd infratentorial, arise from floor of 4th o Hydrocephalus common; ± cysts, hemorrhage • Intraventricular Hemorrhage (Mimic) o Typically associated with trauma o May be primary presentation of AVM o Acutely, hyperdense blood may mimic intraventricular Ca++ o May result in Ca++ in chronic phase • Choroid Plexus Papilloma o Intraventricular, papillary neoplasm derived from choroid plexus epithelium o Child with strongly enhancing, lobulated intraventricular mass; Ca++ in 25% o 50-70% - atrium of lateral ventricle o 4th ventricle most common site in adults • Sub ependymal Giant Cell Astrocytoma o Enhancing mass at foramen of Monro o Ca++ common; hydrocephalus common o Occurs in 15% of TSC patients

INTRAVENTRICULAR

CALCIFICATlON(S)

(J)

""r::

• Subependymoma o Rare, benign, well-differentiated, and intraventricular, ependymal tumor o T2 hyperintense lobular, nonenhancing intraventricular mass o May see cysts, hemorrhage, Ca++ o Inferior 4th (60%) > lateral ventricle • Central Neurocytoma o Typical "bubbly" appearance; Ca++ common o Lateral ventricle, attached to septum pellucidum o Moderate to strong enhancement • Cavernous Malformation o Rarely intraventricular, 2.5-11 % of cases o Ca++ & T2 hypointense hemosiderin rim common o Enhancement variable • TORCH, General (Mimic) o Acronym for congenital infections caused by transplacental transmission of pathogens o Taxa, CMV, HIV, & rubella cause parenchymal &/or periventricular Ca++ Helpful Clues for Rare Diagnoses • Medulloblastoma (PNET-MB) o Malignant, invasive, highly cellular embryonal tumor o 4th ventricle tumor, arise from roof (superior medullary velum) o Hydrocephalus common (95%) o 90% hyperdense related to high nuclear:cytoplasmic ratio

Physiologic

Calcification,

Choroid

Plexus

Axial NECT in a padent who presented following trauma. Note symmetric physiologic Ca++ ~ in the auia of the lateral ventricles in this young patient.

Ca++ in up to 20% Small tumor cysts/necrosis in 40-50% • Choroid Plexus Carcinoma o Child < 5 y, with enhancing intraventricular mass & ependymal invasion o Ca++ in 20-25% o Almost all in lateral ventricle o May see necrosis, cysts & hemorrhage • Craniopharyngioma o Partially Ca++, partially solid, cystic suprasellar mass in a child o Typically sellar & suprasellar o Rare within third ventricle o o

Alternative Differential Approaches • Calcified intraventricular mass: Adult o Meningioma (lateral ventricle) o Subependymoma (4th> lateral ventricle) o Central neurocytoma (lateral ventricle) o Cavernous malformation o Neurocysticercosis (4th ventricle) • Calcified intraventricular mass: Child o Ependymoma (4th ventricle) o Choroid plexus papilloma (lateral> 4th ventricle) o Subependymal giant cell astrocytoma (foramen of Monro) o Medulloblastoma (4th ventricle) o Craniopharyngioma (3rd ventricle)

Choroid

Plexus Cyst

Axial CECT shows bilateral choroid plexus cysts (xanthogranulomas), a common incidental finding in older patients. The cysts are calcified =::I & show mild rim-enhancement.

I 3 63

INTRAVENTRICULAR

C/)

c

.Q OJ Q)

0:::

(Left) Axial T2' CRE MR shows mullifocal

C/) Q)

u ·C C Q)

> C nl

Ca++

in

this patient with nodular calcified NCe. Note focal intraventricular Ca++ Ca++ typically occur at convexity subarachnoid spaces. (Right) Axial N[CT shows globular Ca++ within the ventricles in unusual

•.... 1IJ

locations

"C

the presence of extensive &/o( unusual intraventricular Ca++ suggests NF2.

c nl

Monro).

(foramen In

a

of

young patient,

(Left) Axial NECT shows bilateral Ca++ subependymal nodules in this tuberous sclerosis patient. These occur along caudothalamic groove, atria, & temporal horns. 50% calcify; progressive after I year. (Right) Axial NECT shows a hyperdense mass with central ~ & rim Ca++ in the left lateral ventricle.

Note associated

ventricular enlargement Approximately I % of meningiomas

~.-

are

intraventricular.

(Left) Axial NECT shows a partially calcified mass within the 4th ventricle. Ependymomas often partially calcify (50%) & characteristically extrude through the 4th ventricular foramen. (Right) Axial N[CT shows a lobulated mass in the atrium of the lateral ventricle with focal Ca++ 81. Note the marked expansion & septation of the lateral ventricle

=.

I 3 64

CAlCiFICATION(S)

I NTRAVENTRICU

LAR CALCIFICATION

(5)

C/l

" c: Ql

:J

Co

..,

lJl Ql

(Left) Axial NECT shows a calcified

foramen

or Monro

mass 81. Note dilated lateral ventricle

indicating

ventricular obstruction. Often, hydrocephalus is first presentation of tuberous sclerosis. (Rigl1t) Axial NECT shows a densely calcified 4th ventricular mass. Although

:J

<

;:l. :::!. Cl

CO en

rare in subependymomas, Ca++

is more commonly

seen in 4th ventricle subependymomas and in very large subependymomas.

;:0

CO

o' :::l

en

Central Neurocytoma

Cavernous Malformation (Left) Axial NECT shows a variant case of a solid central

neurocytoma with no cystic component Note mass at the foramen of Monro with a focal Ca++ =11. Lack of cysts suggests a subependymoma or SCCA (Right) Axial NECT shows a hyperdense mass centered in the lateral ventricles with rim Ca++ m. The mass consists of multiple I'focu/es" or "cysts" consistent with hemorrhages of different ages.

Medulloblastoma (PNET-MB) ~eft)Ax~/NECTshowsa large, 4th ventricular mass I:llIthat is higher in attenuation than brain parenchyma. Note a small focus of Ca++ 81 & hydrocephalus in this child with medulloblastoma. (Right) Axial NECT shows a

hypodense mass centered over a 3rd ventricle with a delicate rim of Ca++ 1:llI. Craniopharyngiomas are typically sellar & suprasellar, but they rarely occur in the third ventricle.

I 3 65

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PERIVENTRICULAR

CALCIFICATION

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Common • TORCH, General o CMV, Congenital o Toxoplasmosis, Congenital o Herpes Encephalitis, Congenital o HIV, Congenital o Rubella, Congenital • Tuberous Sclerosis Complex Less Common • Neurocysticercosis • Tuberculosis • Ventriculitis (Chronic) • Germinal Matrix Hemorrhage Rare but Important • Radiation and Chemotherapy • Pseudo-TORCH o Aicardi-Goutieres Syndrome o Coats-Plus Syndrome

•

•

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Look for associations o Brain destruction o Malformations o Other loci of calcification o History Helpful Clues for Common Diagnoses • TORCH, General o Classic acronym for congenital infections • Caused by transplacental transmission of pathogens • TOxoplasmosis, Rubella, Cytomegalovirus, Herpes • All cause parenchymal Ca++ • Most can cause lenticulostriate mineralization, vasculopathy • Some (CMV) cause migrational defects • Some (syphilis, herpes) cause meningitis, meningoencephalitis • Some (e.g., CMV) cause germinolytic cysts • Others (e.g., rubella, HSV) cause striking lobar destruction/encephalomalacia o Congenital HIV, syphilis also considered part of TORCH

I 3 66

Consider congenital HIV if bilateral symmetric basal ganglia C++ identified in child> 2 months old! o If congenital infection is diagnostic consideration, obtain NECT to detect Ca++ CMV, Congenital o Most common cause of intrauterine infection in USA o Timing of infection predicts pattern of damage o Hypomyelination o Cortical gyral anomalies o Microcephaly o Symmetric periventricular Ca++ in 30-70% Toxoplasmosis, Congenital o Periventricular & scattered Ca++ o Hydrocephalus (colpocephaly-like) Herpes Encephalitis, Congenital o Calcification pattern varies in HSV2 • Asymmetric periventricular • Scattered periventricular and deep gray • Subcortical white matter & cortex • Calcification pronounced in foci of hemorrhagic ischemia • Like rubella, rare cause of "stone brain" o Brain atrophy or cystic encephalomalacia • Focal or diffuse HIV, Congenital o Vertical HIV infection o Basal ganglia Ca++, atrophy o Consider congenital HIV if bilateral symmetric basal ganglia C++ identified in child> 2 months old! Rubella, Congenital o Periventricular and scattered o Scattered or hazy basal ganglia Ca++ o Rare "stone brain" • Extensive gyral calcification & gliosis o Micro-infarcts Tuberous Sclerosis Complex o Look for cutaneous markers of TS o Subependymal nodules • Variable-sized periventricular calcifications o Cortical tubers also calcify o

DIFFERENTIAL DIAGNOSIS

•

•

•

Helpful Clues for Less Common Diagnoses • Neurocysticercosis o Best clue: Dot inside cyst o Usually convexity subarachnoid space o Also gray-white junction, intraventricular o Nodular calcified (healed) stage

PERIVENTRICULAR

• Shrinks to small Ca++ puncta or nodule • Tuberculosis o Best diagnostic clue: Basal meningitis and pulmonary TB o Acute • Typically basal meningitis • ± Localized CNS tuberculoma o Chronic • Residual pachymeningeal • ± Localized Ca++ o "Target sign" • Calcification surrounded by enhancing rim (not specific) • Ventriculitis (Chronic) o Areas of prior hemorrhagic infarction prone to dystrophic calcification • Germinal Matrix Hemorrhage o Occasional ependymal, germinal matrix calcific foci Helpful Clues for Rare Diagnoses • Radiation and Chemotherapy o History! o Mineralizing microangiopathy • Pseudo-TORCH o Aicardi-Goutieres Syndrome • "Mendelian mimic of congenital infection" • Multifocal punctate calcifications • Variable locations including periventricular white matter, basal ganglia, dentate nuclei • Elevated CSF interferon (IFN-a) • TREXI mutations in some

CMV, Congenital

within

cortex

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in this deaf child,

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Coats-Plus Syndrome • a.k.a., cerebroretinal microangiopathy with calcifications and cysts (CRMCC) • Ocular coats: Retinal telangiectasia & exudate • CNS small blood vessel calcification • Extensive thalamic and gyraJ calcification • Defects of bone marrow & integument • Growth failure

SELECTED 1.

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REFERENCES

Briggs TA et al: Cerebroretinal microangiopathy with calcifications and cysts (CRMCC). Am J Med Genet A. I 46A(2): 182-90, 2008 Crow YJ et al: Aicardi-Goutieres syndrome: an important Mendelian mimic of congenital infection. Dev Med Child Neural. 50(6):410-6, 2008 Rice G et al: Clinical and molecular phenotype of Aicardi-Goutieres syndrome. Am J Ilum Genet. 81(4):713-25,2007 Linnankivi T et al: Cerebrorelinal microangiopathy with calcifications and cysts. Neurology. 67(8):]437-43, 2006 Abdel-Salam GM et al: Aicardi-Goutieres syndrome: clinical and neuroradiological findings of ]0 new cases.Acta Paediatr. 93(7):929-36, 2004 Malinger Get al: Fetal cytomegalovirus infection of the brain: the spectrum of sonographic findings. AJNR Am J Neuroradiol. 24(1):28-32, 2003 Numazaki K et al: Intracranial calcification with congenital rubella syndrome in a mother with serologic immunity. J Child Neurol. 18(4):296-7, 2003 Tanaka F et al: Association of osteopontin with ischemic axonal death in periventricular leukomalacia. Acta Neuropathol. 100(1):69-74,2000

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CMV, Congenital

Coronal NECT shows classic findings of TORCH. Note linear periventricular Ca++ ~ with scattered Ca++ foci

intrauterine CMV exposure.

CALCIFICATION

suggesting prior

Sagittal T2WI MR shows a thick cortex with small gyri, hyperintense white maNer and a thin layer of calcification!J:.:l in the same 18 month old deaf toddler.

I 3 67

PERIVENTRICUlAR

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(Left) Axial NECT shows basal ganglia SII and perivenuicular calcifications ~ in a child with typical colpocephalic dilation of the ventricles. (Right) Coronal T2WI MR shows marked ventriculomegaly and loss of the perivenlricular while

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III

and basal ganglia calcifications are occult on MR but do involve the right choroid plexus glomus

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(Left) Axial NECT shows scattered and peri ventricular calcifications. In this child, there is unilateral left-sided colpocephaly~. Note severe cortical mantle thinning SII over the cofpocephalic ventricle. (RighI) Axial T2' GRE MR shows similar findings, although the calcifications

e:I are not as well-visualized.

(Left) Axial NEeT in child who survived congenital herpes encephalitis shows scattered parenchymal calcifications ~. (Right) Axial NECT in same patient shows calcifications of the infarcted Rolandic cortex SII. They can be variable, predominantly involving damaged brain.

I 3 68

CALCIFICATION

PERIVENTRICUlAR

CALCIFICATION

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Rubella, Congenital (Left) Axial NECT shows hazy, symmetric basal ganglia calcification with diffusely prominent sulci and cisterns consistent with volume loss. In this one year old, the findings are highly suggestive of congenital I II V. (Right) Axial NEeT shows basal ganglia calcifications 81 and diffuse white matter

=

hypoinlensily.

There are faint

bilateral subependymal calcifications lining the

posterior horns

=.

Tuberous Sclerosis Complex (Left) Sagittal ultrasound in child with TSC, subependymal giant cell astrocytoma shows mass indenting lateral ventricle B. Tumor shows increased echogenicity (Right) Axial NECT shows variable

=.

calcification

in the

subependymal nodules. Calcification in these lesions progresses over lime.

(Left) Axial CECT shows disseminated "miliary" form of neurocysticercosis (NCC).

Note numerous cysts, each with a hyperdense central "dot" representing scolex small calcific foci, some of which are peri ventricular Eel cause

=. Innumerable

classic "starry sky" appearance of healed NCe. (Right) Axial T2' CRE MR show scattered calcifications throughout the brain. A few are in the deep gray structures and one is

=

intraventricular ~.

I 3 69

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CALCIFICATION

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(Left) Axial NECT shows nodular calcification E2 along the postero-medial temporal lobe on the tentorial surface. (RighI) Axial CECT in same patient shows the calcification to be largely obscured by the thick rind of pachymeningeal and leptomeningeal thickening and enhancement

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H2.

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(Leh) Axial T7 WI MR early in the course of the disease shows hemorrhagic infarction H2 of the ependyma and subependymal brain. (RighI) Axial NECT shows subependymal tissue necrosis and calciFication

the same areas

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m.

Germinal aeft)Ax~/N[CTshows while matter deficiency

due

to perivenlricular

leukomalacia. The gray matter I!:'J nearly approximates the ventricular surface. Small perivenlricular calcifications Ea are present at the site of prior germinal matrix hemorrhage. (Right) Axial NECT shows bilateral symmetric calcifications at the gray-white junction H2 due to mineralizing microangiopathy following radiation and chemotherapy.

I 3 70

Matrix

Hemorrhage

Radiation and Chemotherapy

PERIVENTRICULAR

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CALCIFICATION

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(Left) Axial T2WI MR from the same patient shows while mailer demyelination l:l:I. The calcificalions are occult. (Right) Axial NECT shows brain alrophy and bilaleralsymmelrical calcifications in the basal ganglia ~. Extension into the corona radiata (nol shown) was also present

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Syndrome (Left) Axial PO FSEMR shows extensive abnormal signal of white maller and volume 1055of gray & while matter. Faint calcifications ~ are presenl, allhough they are less well seen on MR lhan on NECT (Right) Coronal T2WI MR again shows severe volume loss. Faint perivenlricular

calcificalions ? and basal ganglia calcificalions ~ are present, mimicking the appearance of TORCH infections.

Coats-Plus

Syndrome

Coats-Plus

Syndrome (Left) Axial NECT shows extensive Byra!, brainstem, and perivenlricular calcifications. The brainstem is also swollen ~ and low density. Note post-operative change of lhe righl globe. (Right) Axial NECT shows dense perivemricular calcification that extends to involve the sparse subcortical white maller posleriorlya lhe fronlal while maller, cortex, and lhalami~. The pal/ern of calcification is lypical, although swelling occurs

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Obstructive Hydrocephalus Drug Abuse CADASIL Susac Syndrome

Rare but Important • Metachromatic Leukodystrophy • X-Linked Adrenoleukodystrophy • Mucopolysaccharidoses • TORCH Infections

(MLD)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Peri ventricular T2/FLAIR hyperintense lesions are often nonspecific, with significant overlap among etiologies • These guestions help narrow differential o How old is the patient? o Volume loss vs. mass effect? o Are there T2 * GRE "black dots"? o Is there enhancement? o Is the corpus callosum (CC) involved? o Are the basal ganglia involved?

I 3 72

Helpful Clues for Common Diagnoses • Aging Brain, Normal o Smooth, thin rim of peri ventricular hyperintensity, wide sulci, prominent ventricles o Sparing of cortex, subcortical/deep white matter (WM) & basal ganglia (BG) • Arteriolosclerosis o Patchy confluent & focal lesions; subcortical/deep WM & BG involved; ± cortical infarcts oGRE: Associated "black dots" (overlap with chronic hypertension & amyloid)

• Multiple Sclerosis o Linear/ovoid callosal & perpendicular caIJososeptallesions • Infratentorial (esp. brachium pontis, brainstem), optic nerve, spinal cord o T1 MR: Hyperintense rim: Chronic plague o T1 C+ MR: Enhancement with active disease: Nodular> ring> semilunar • ADEM o Lesions have less mass effect than expected for size; BG lesions common o T1 C+ MR: Enhancement & appearance may mimic MS; often need flu exam o Clinical: Viral prodrome or recent vaccination; monophasic • Diffuse Axonal Injury (DAI) oGRE: Multiple "black dots" at gray/white interface, CC, deep gray matter, brainstem o Clinical: Trauma patient • Metastases, Parenchymal o T1 C+ MR: Multiple enhancing masses at gray/white interface o T2/FLAIR: Hyperintensity has mass effect (vasogenic edema) Helpful Clues for less Common Diagnoses • Radiation and Chemotherapy o Numerous appearances based on injury • Periventricular leukoencephalopathy: Confluent T2 hyperintensity, spares subcortical V-fibers & CC • PRES: Symmetric posterior circulation subcortical/peri ventricular T2 hyperin tensi ty • Radiation necrosis: Vasogenic edema surrounds irregular, enhancing lesion(s) • Periventricular Leukomalacia (PVL) o Early: Periventricular cystic changes o Late: Undulating ventricular borders, ventriculomegaly, WM volume loss o Clinical: Pre term birth, spastic diplegia, visual & cognitive impairment • Lyme Disease o T1 C+ MR: Multiple enhancing cranial nerves; CN7 common o WM lesions may be identical to MS o Clinical: Meningoencephalitis, ± history of skin rash (erythema migrans); higher prevalence in New England • Vasculitis o Restricted diffusion in acute phase

PERIVENTRICULAR

T2/FLAIR

HYPERINTENSE

LESIONS

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T2/FLAIR MR: Ranges from normal to patchy asymmetric hyperintensity in multiple small vessel territories o DSA: Regions of alternating stenosis & dilatation primarily involving 2nd, 3rd order branches Obstructive Hydrocephalus o Periventricular "halos": Fingers of CSF-like hyperintensity most pronounced at ventricular horns o Ventricles dilated without sulcal widening or cortical volume loss Drug Abuse o Confluent peri ventricular WM; corticospinal tract & deep grey matter; often hemorrhagic o Cerebellar involvement in absence of hypertension, characteristic of inhaled heroin ("chasing the dragon") o Can cause a vasculitis CADASIL o Subcortical lacunar infarcts & leukoencephalopathy in young adult o Anterior temporal pole & external capsule lesions highly sensitive/specific o Frontal lobe has highest lesion load Susac Syndrome o Central CC > callososeptallesions o WM lesions may be identical to MS o Clinical triad: Encephalopathy, hearing loss, branch retinal artery occlusions o

•

•

•

•

Axial FLAIR MR shows prominent venlric/es, wide cortical sulci, and a thin rim of periventricular while matter hyperintensity 1:::1 in an elderly individual.

III

Helpful Clues for Rare Diagnoses

• Metachromatic Leukodystrophy (MLD): Confluent "butterfly-shaped" cerebral hemispheric WM T2 hyperintensity • X-Linked Adrenoleukodystrophy: Enhancing peri-trigonal WM demyelination • Mucopolysaccharidoses: T2 hyperintensity surrounds dilated MPS-filled PVS • TORCH Infections: Variable WM T2 hyperintensity, ± calcification Alternative

Differential

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• Patient age o Elderly: Normal aging, arteriolosclerosis, metastases o Young adult: MS, ADEM, vasculitis, drug abuse, CADASIL o Infant to child: ADEM, PVL, MLD, TORCH • Volume loss vs. mass effect o Volume loss: Normal aging, arteriolosclerosis, MS, PVL, CADASIL o Mass effect: MS (active), ADEM, metastases, obstructive hydrocephalus • T2 * GRE "black dots" present o Arteriolosclerosis, DAI, periventricular leukoencephalopathy (+ radiation-induced vascular lesions), chronic hypertension • Enhancement: MS, ADEM, Lyme disease, metastases, radiation necrosis • Corpus callosum involved: MS, ADEM, DAI, Susac syndrome • Basal ganglia involved: Arteriolosclerosis, ADEM, DAI, vasculitis, drug abuse

Axial FLAIR MR shows confluent periventricular and subcortical hyperintensity, focal right thalamus SI and left putamen I!:ll hyperintensity with diffuse white malLer volume 1055.

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subcortical and callososeptal ~ hyperintense lesions. The perpendicular

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at

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but asymmetric

enhancemenl. exhibilless expected

with

Lesions often

mass effect than for size.

Diffuse Axonal Injury (DAI)

Metastases, Parenchymal

(Left) Axial T2WI MR shows hyperintensity in corpus callosum splenium SI caused by axonal injury. GRE scan (not shown) disclosed some focal hemorrhages. (Right) Axial T2WI MR

shows two hyperintense lesions It] representing lung metastases that showed enhancement

following

contrast. Without contrast, may be difficult to differentiate these lesions from other WM diseases.

it

Radiation and Chemotherapy (Left) Axial T2WI MR shows treatment-related leukoencephalopathy of the periventricular & subcortical WM with sparing of the subcortical U-fibers ~ and corpus callosum, which is characteristic of this type of injury. (Right) Axial T2WI MR shows the typical "square comers" of periventricular leukomalacia of prematurity

I 3 74

at the junction

of the body and trigones of the lateral ventricles ~. Also note the typical periventricular hyperinlensily

SI

Periventricular leukomalacia

(PVl)

PERIVENTRICULAR

CIl

T2/FLAIR HYPERINTENSE LESIONS

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Vasculitis (Left) Axial T2WI MR shows multifocal hyperintense lesions in the subcortical & perivenlricular

=.

WM & corpus

callosum Lesions did not enhance following contrast. Lyme disease often mimics MS & can be confirmed with laboratory tests such as PCR & ELISA. (Right) Axial T2WI MR shows multiple foci of high signal in the peri ventricular WM & basal ganglia caused by chemical vasculitis. These T2 lesions are often associated with restricted OWl in acute phase.

=

Obstructive

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Hydrocephalus (Left) Axial FLAIR MR shows fingers of hyperintensity most pronounced at the ventricular horns ~ related to transependymal flow of CSF. The ventricles are dilated without widening of the cortical sulci. (Right) Axial FLAIR MR shows symmetric corticospinal tract corpus callosal &

a

confluent

perivenlricular

=

hyperintensity, often found in drug-induced leukoencephalopathy.

CADASIL

Susac Syndrome (Left) Axial FLAIR MR shows hyperintensity & volume 1055 in the subcortical anterior temporal=& periventricular WM in a 32 year old male with CADASIL, confirmed by chromosomal analysis. (Right) Sagiltal fLAIR MR shows central corpus callosum hyperintensities with relative sparing of the callososeplal imerface. Susac syndrome often mimics MS on MR but has a clinical triad which confirms the diagnosis.

=

I 3 75

SECTION 4 Extra-Axial Spaces and Subarachnoid Cisterns Anatomically Based Differentials Cistern, Subarachnoid Space Normal Variants Epidural Mass, Brain Enlarged Sulci, Generalized Effaced Sulci, Generalized Effaced Sulci, Focal Interhemispheric Fissure Cysts CPA Mass, Adult Cystic CPA Mass Prepontine Cistern Mass Cisterna Magna Mass Foramen Magnum Mass

1-4-2 1-4-4 1-4-8 1-4-12 1-4-16 1-4-20 1-4-24 1-4-28 1-4-32 1-4-38 1-4-42

Generic Imaging Patterns Enhancing Cranial Nerve(s) CSF-like Extra-Axial Fluid Collection CSF-like Extra-Axial Mass Sulcal/Cisternal Enhancement Fat in SulcijCisterns/Ventricles

Modality-Specific

1-4-46 1-4-50 1-4-52 1-4-54 1-4-58

Imaging Findings

Extra-Axial Flow Voids T1 Hyperintense CSF FLAIRHyperintense CSF T2 Hypointense Extra-Axial Lesions Hyperdense CSF Hyperdense Extra-Axial Mass(es) Hypodense Extra-Axial Mass(es)

1-4-60 1-4-62 1-4-64 1-4-68 1-4-72 1-4-74 1-4-76

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SUBARACHNOID

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VARIANTS

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DIFFERENTIAL DIAGNOSIS Common • Cavum Septi Pellucidi (CSP) • Mega Cisterna Magna • MR Artifacts, Flow-Related • Enlarged Subarachnoid Spaces Less Common • Cavum Velum Interpositum (CVI) • Enlarged Optic Nerve Sheath Rare but Important • Blake Pouch Cyst • Liliequist Membrane

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ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Normal variants have CSF density/intensity • Important to recognize normal variants & not mistake for more ominous pathology Helpful Clues for Common Diagnoses • Cavum Septi Pellucidi (CSP) o Elongated finger-shaped CSF collection between frontal horns of lateral ventricles o Posterior continuation between fornices often associated (cavum vergae) • Mega Cisterna Magna o Enlarged cisterna magna communicates freely with 4th ventricle & basal cisterns o Large posterior fossa o Normal vermis o Cistern crossed by falx cere belli, tiny veins o Occipital bone may appear scalloped

• MR Artifacts, Flow-Related o CSF flow artifact is common in basal cisterns, ventricles o Commonly seen on FLAIR MR o Artifact often extends outside skull • Enlarged Subarachnoid Spaces o Idiopathic enlargement of subarachnoid spaces (SAS) during first year of life o Increased head circumference (> 95%) a Resolves without therapy by 12-24 months Helpful Clues for Less Common Diagnoses • Cavum Velum Interpositum (CVI) o Triangular-shaped CSF space between bodies of lateral ventricles, below fornices, above 3rd ventricle o Often elevates, splays fornices & causes inferior displacement of internal cerebral veins & 3rd ventricle • Enlarged Optic Nerve Sheath o May occur as normal variant o Occurs in idiopathic intracranial hypertension (pseudotumor cerebri), NFl Helpful Clues for Rare Diagnoses • Blake Pouch Cyst o Failure of regression of Blake pouch cyst causes compression of basal cisterns o Free communication of 4th ventricle with prominent inferior CSF space • Liliequist Membrane o Thin arachnoid membrane separates suprasellar, interpeduncular, & prepontine cisterns

Cavum Septi Pellucidi (CSP)

I 4 2

=

Axial T1WI MR shows a cavum sepli pellucidi with posterior extension into a cavum vergae B, seen as a CSF-signalcollection that lies between the bodies of the lateral ventricles.

Sagiaal T1WI M R shows a prominent retrocerebellar CSF space Sl a mega cisterna magna. This normal variant requires no lreatment. Note normal vermis & 4th

ventricle.

CISTERN, SUBARACHNOID

SPACE NORMAL

CII :>:"

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=,

which can mimic

a mass. This artifact is often seen on FLAIR MR & can be confirmed on spin echo sequences (T!).

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Flow-voids due

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veins ~ are seen, conFirming that these are enlarged subarachnoid spaces & not subdural or epidural collections. This condition typically resolves without therapy. (Right) Sagittal T! WI MR shows a CVI that flattens the internal cerebral veins ::> &.

=

compresses the quadrigeminal cistern ~. Inferior displacement of the 3rd ventricle is also typical.

Enlarged Optic Nerve Sheath

Blake Pouch Cyst (Left) Axial TlWI MR shows prominent, dilated optic nerve sheaths & flattened orbits. While patulous optic nerve sheaths can occur as a

normal variant, the imaging findings together with clinical presentation are consistent with idiopathic intracranial hypertension. (Right) Axial T2WI MR shows an enlarged posterior fossa & Blake pouch cyst ~ The vermis is typically rotated but normal

in these patients.

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DIFFERENTIAL DIAGNOSIS Common • Epidural Hematoma • Meningioma • Dural Metastasis less Common • Lymphoma • Neurosarcoid • Epidural Empyema Rare but Important • Tuberculoma • Plasmacytoma • Meningioma, Atypical and Malignant • Hemangiopericytoma • Extramedullary Hematopoiesis • Leukemia • Gliosarcoma • Rosai-Dorfman Disease • Langerhans Cell Histiocytosis • Neurosyphilis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Pattern of enhancement o No enhancement: Hematoma o Rim enhancement: Abscess, rarely leukemia o Heterogeneous enhancement: Atypical or malignant meningioma, hemangiopericytoma, gliosarcoma o Diffuse enhancement: Most other lesions • Hyperdense: ECT o Epidural hematoma o Meningioma o Lymphoma o Tuberculoma o Plasmacytoma: Mildly hyperdense o Meningioma, atypical and malignant o Hemangiopericytoma o Leukemia o Epidural empyema: Sometimes

I 4 4

Helpful Clues for Common Diagnoses • Epidural Hematoma o Trauma most common etiology • Classic "lucid interval" in only 50% • Most EDHs occur at impact ("coup") site • Overlying fracture common 85-95%

• "Swirl sign" from rapid bleeding, unretracted clot o Arterial EDH = 90% • With fracture, nearly always secondary to MMA groove fracture o Venous = 10% • Adjacent to venous sinus • Meningioma o Hyperdense (70-75%) because of tightly packed cells ± calcification o Homogeneous intense enhancement (> 90%) o Vascular pedicle common/increased vascular markings o Underlying hyperostosis may be present o Peritumoral edema (60%) o MRS: Elevated alanine on short TE • Dural Metastasis o Underlying bone destruction/scalp involvement common • Fat-saturation helpful to distinguish enhancement from normal hyperintense marrow and scalp fat o Often multiple lesions o Often diffuse nodular enhancement o Primary malignancy • Breast, lung, melanoma, prostate most common Helpful Clues for less Common Diagnoses • Lymphoma o Dural-based lesions usually related to known systemic disease (secondary lymphoma) although occasionally seen in primary CNS lymphoma (PCNSL) • Often affects brain and spine • PCNSL: Usually basal ganglia, periventricular WM o Hyperdense on unenhanced CT/slightly hypointense on T2WI MR because of tightly packed blue cells o Homogeneous enhancement common • Neurosarcoid o Dural, leptomeningeal> > parenchymal disease • Especially basal cisterns involving optic chiasm, hypothalamus, infundibulum, cranial nerves (CN) • Lacy leptomeningeal enhancement typical • Hypointense dural lesions and subarachnoid space/sulci

EPIDURAL MASS, BRAIN

Systemic disease usually present • Chest radiograph may be helpful (lungs affected in > 90% NS patients) o African-American:Caucasian-American = 10:1

Gender: M:F = 2:1 • Epidural Empyema o Extra-axial collection with rim enhancement o MR best to demonstrate presence, nature, extent, and complications • Best imaging technique: T1 C+ and DWI • Complications: Cerebritis/cerebral abscess, dural venous sinus thrombosis, ischemia o Extra-axial collection, typically isodense to hyperdense to CSF o Look for underlying sinusitis/mastoiditis o

Helpful Clues for Rare Diagnoses • Tuberculoma o Hyperdense on NECT CT/T2 hypointense • Plasmacytoma o Usually homogeneous, mildly hyperdense on NECT • Meningioma, Atypical and Malignant o Bone/scalp/brain invasion common o Irregular heterogeneous enhancement pattern • Hemangiopericytoma o Lobular, enhancing, extra-axial mass with dural attachment ± skull erosion o May mimic meningioma, but without Ca++ or hyperostosis

Axial NEG sholVs a la'ge, slighUy inhomogeneously hyperdense, right epidural hematoma C]_ Foci of hypodensity I?J within the collection represent hyperacute hemorrhage ("swirl sign").

Typically involve falx, tentorium, or dural sinuses o Marked enhancement, often heterogeneous o Elevated myoinositol on short TE MRS may help to distinguish from meningioma Extramedullary Hematopoiesis o Juxta-osseous smooth homogeneous masses in patients with chronic anemias or marrow depletion o Soft tissue filling paranasal sinus(es) o Homogeneous enhancement Leukemia o Homogeneous enhancement • Rarely mimic abscess with enhancing rim o Most often a complication of acute myelogenous leukemia (AML) Gliosarcoma o Rare malignant neoplasm with both glial, mesenchymal elements o Heterogeneously enhancing mass with dural invasion, ± skull involvement Rosai-Dorfman Disease o Rare disease of the lymphoid tissues o Neurologic involvement is rare, but typical dural-based lesions may mimic meningioma Langerhans Cell Histiocytosis o Destruction of adjacent bone without periosteal reaction o Diabetes insipidus Neurosyphilis o Dural-based gumma may mimic meningioma o

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I 4 6

Lymphoma

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Gliosarcoma

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Cell Histiocytosis (Left) Axial T1 C+ MR shows

a left frontal mass with heterogeneous, thick, irregular enhancement and central necrosis, typical for gliosarcoma. Note the dural invasion SII. (Right) Axial T1 C+ FS MR shows a destructive, avidly enhancing, mastoid lesion with epidural extension

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I 4 7

ENLARGED SULCI, GENERALIZED

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Common • Aging Brain, Normal • Dementias o Alzheimer Dementia o Vascular Dementia o Dementia with Lewy Bodies o Frontotemporal Dementia • Chronic Alcoholic Encephalopathy • HIV Encephalitis Less Common • Chronic Hepatic Encephalopathy • Remote Generalized Insult o Trauma o Hypoxic Ischemic Encephalopathy o Meningitis o Encephalitis (Miscellaneous) o Multiple Sclerosis (Longstanding) o Radiation and Chemotherapy o Other Toxic/Metabolic Insults • Enlarged Subarachnoid Spaces (Benign Macrocrania of Infancy) Rare but Important • Steroids • Volume Loss Secondary to Nutrition or Hydration Status • Miscellaneous Neurodegenerative Disorders o Corticobasal Degeneration o Parkinson Disease o Huntington Disease o Multiple System Atrophy • Creutzfeldt-]akob Disease (ClD)

ESSENTIAL INFORMATION

I 4 8

Key Differential Diagnosis Issues • Some age-related volume loss (especially cortical) normal • Location helpful o Generalized or disproportionately affecting some parts of brain more than others? o Parieto-temporal/hippocampal (Alzheimer), frontotemporal (FTD or Lewy body disease) vs. parieto-occipital (Heidenhain variant of C]D) • Clinical information helpful o History of trauma, drug abuse, stroke, infection o

Dehydration, steroids may cause temporary

sulcal enlargement

o

Metabolic/demyelinating disorders (inherited or acquired, longstanding) may cause volume loss, sulcal enlargement

Helpful Clues for Common Diagnoses • Aging Brain, Normal o White matter volume decreases o Mild/moderate ventricular, sulcal enlargement o Thin periventricular hyperintense rim o Scattered white matter hyperintensities increase with age, normal o "Black dots" on GRE/SWI are NOT normal • Chronic hypertensive encephalopathy • Cerebral amyloid angiopathy • Dementias o Evaluate for other treatable (potentially treatable) causes of dementia (e.g., repeated trauma with subdural hematoma) • Endocrinopathy (e.g., hypothyroidism) • Alcohol/drug abuse • Depression ("pseudodementia") o General imaging findings • Differentiation solely on basis of CT, standard MR difficult • PET, fMRI helpful o Alzheimer Dementia • Temporal (especially hippocampal), parietal atrophy • Hypometabolic areas, perfusion deficits o Vascular Dementia • Second most common dementia • Volume loss, multiple chronic infarcts, lacunes • Multifocal white matter disease, often confluent (arteriolosclerosis) o Dementia with Lewy Bodies • Visual/a uditory hallucinations, delusions • Entire brain hypo metabolic (including visual cortex, cerebellum) o Frontotemporal Dementia • Anterior frontotemporal atrophy • "Knife-like" gyri • Up to 40% familial (tau mutations) • Chronic Alcoholic Encephalopathy o Generalized & cerebellar (superior vermian) atrophy o Hyperintense basal ganglia on Tl WI suggests chronic hepatic encephalopathy o Polydrug abuse common o Methanol less common; causes hemorrhagic putaminal necrosis

ENLARGED SULCI, GENERALIZED

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• HIV Encephalitis o Most common imaging finding in brains of HIV/AIDSpatients o Diffuse atrophy, "hazy" white matter hyperin tensi ty Helpful Clues for Less Common Diagnoses • Chronic Hepatic Encephalopathy o History of alcohol abuse, liver disease common o Atrophy (especially cerebellum), T1 shortening (especially globi pallidi) • Remote Generalized Insult o Any longstanding, sufficiently severe disease may cause brain atrophy, sulcal prominence o Trauma, infection, demyelination, radiation/ chemothera py, toxic/metabolic/hypoxic insult • If patients survive, brain often shrinks and sulci enlarge • Very chronic MS causes severe white matter loss, sulci enlarge, basal ganglia become hypointense • Enlarged Subarachnoid Spaces (Benign Macrocrania of Infancy) o Enlarged SASscommon in infancy • Bifrontal, symmetric • Peaks about 7 months, tends to resolve after age 1 o Danger signs • Rapid t OFC or signs of t ICP • Asymmetric, persisting after 1 year • Asymmetric

Helpful Clues for Rare Diagnoses • Steroids o May cause transient, reversible sulcal enlargement • Volume Loss Secondary to Nutrition or Hydration Status o Starvation, dehydration (may be reversible) • Miscellaneous Neurodegenerative Disorders o Multiple system atrophy (midbrain, corticobasal degeneration) o Parkinson-associated dementia (midbrain with loss of pars compacta) • Creutzfeldt-]akob Disease (ClD) o Early findings • Hyperintensity in anterior basal ganglia • "Pulvinar sign" (hyperintensity in posterior thalamus) • FLAIR,DWI positive o Later findings • Rapidly progressive atrophy, ventricular dilatation o Heidenhain variant • Peripheral cortex, especially occipital

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Axial T2WI MR in a 63 year old man with Alzheimer dementia shows large sylvian fissures, la/eral ventricles. The parie/o-occipital sulci are lessseverely affected.

4 9

ENLARGED SULCI, GENERALIZED

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survived, shows generalized atrophy plus symmetric volume loss, hyperintensily in pulamina =1 caudate nuclei 81.

HIV Encephalitis (Left) Axial FlAIR MR in longstanding HIV/AIDS on HAART shows diffuse ventricular, sulcal enlargement with while mailer hyperinlensity and volume loss. (Right) Axial NECT shows prominent bifronlal fluid collections. Note sublle findings for acute 7... subacute ::> subdural blood in Ihis child with repealed

trauma.

I 4 10

nonaccidental

Frontotemporal Dementia

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these are

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Huntington

Disease

Creutzfeldt-Jakob

Disease (CJD) (Left) Axial NECT shows focal caudate atrophy ell with convex frontal horns, generalized volume 1055 with enlarged sulci. (Right) Axial T1 C+ MR in a patient with rapid onset dementia shows generalized left hemispheric atrophy, diffuse gyral enhancement. Basal ganglia were normal. Variant manifestation of C/O.

I 4 11

EFFACED SULCI, GENERALIZED

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DIFFERENTIAL DIAGNOSIS Common • Generalized Cerebral Edema o Cerebral Edema, Traumatic o Hypoxic-Ischemic Encephalopathy o Hypotensive Cerebral Infarction o Toxic/Metabolic Encephalopathies (Many) • Subdural Hematoma, Subacute • Acute Obstructive Hydrocephalus • Meningitis • Aneurysmal Subarachnoid Hemorrhage Less Common • Metastases, Skull and Meningeal • Encephalitis • Thrombosis, Dural Sinus • Thrombosis, Deep Cerebral Venous • Acute Hypertensive Encephalopathy, PRES • Status Epilepticus • Intracranial Hypertension, Idiopathic Rare but Important • Neurosarcoid • Contrast Complications • Brain Death • Cerebral Hyperperfusion

Syndrome

ESSENTIAL INFORMATION

I 4 12

Easy to miss; when in doubt get CECT (look for enhanced cortical veins displaced away from skull) or MR (hyperintense on TlWI) • Acute Obstructive Hydrocephalus o Can be intra- or extraventricular • Intraventricular (look for discrepancy in size of ventricles indicating mass, aqueductal stenosis, etc.) • Extraventricular (CSF absorption alterations, e.g., with acute aneurysmal SAH or meningitis): All ventricles enlarged ± transependymal CSF flow o Any unexplained hydrocephalus on NECT scan should prompt CECT scan or MR without, with contrast • Meningitis o Pyogenic, granulomatous (even neoplastic) meningitis appear similar on imaging • Normal CSF spaces filled with pus or neoplasm - isodense/isointense with brain • Typically enhance strongly, uniformly o Beware: Meningitis is clinical/laboratory diagnosis; early meningitis may have normal imaging! • Aneurysmal Subarachnoid Hemorrhage o Basal, generalized vs. localized (with traumatic SAH) o Hyperdense on ECT scans o Beware: Acute aSAH is isointense with brain on Tl WI (fills normal hypointense CSF spaces), isointense with CSF on T2WI (may be difficult to detect) o

Helpful Clues for Less Common Diagnoses • Metastases, Skull and Meningeal o May fill, obliterate normal CSF spaces o Enhance; look for adjacent skull, dura lesions • Encephalitis o Temporal lobe, insula/cingulate gyrus swelling, hyperintensity: Suspect herpes o Other encephalitides may be nonspecific but look for predilection (e.g., West Nile in basal ganglia, thalamus) • Thrombosis, Dural Sinus o SSS > TS as cause for diffuse brain swelling o TS + vein of Labbe may cause extensive venous ischemia, hemorrhage, frank infarct

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NECT shows hyperdense sinus; CECT ~ "empty delta sign" o Beware: Hyperacute thrombus is isointense on 1'1WI, hypointense on T2WI (may mimic "flow void")! o T2* (GRE, SWI) best MR sequence to show blooming clot • Thrombosis, Deep Cerebral Venous o Hyperdense ICVs, straight sinus o Hyperdense thrombosed rcvs can make NECT look like CECT scan! o Hypodensity in thalami, basal ganglia, internal capsules, deep periventricular white matter • Acute Hypertensive Encephalopathy, o

PRES

Bioccipital cortical/subcortical edema, sulcal obliteration most common o May affect brainstem, cerebellum, basal ganglia, watershed (sometimes ONLY these areas without classic posterior cerebral territory involvement) o Hypodense on NECT, hyperintense on T2WI/FLAIR o Typically does not restrict on DWI • Status Epilepticus o Prolonged seizure causes hypermetabolic state, blood-brain-barrier leakage o Imaging within 24 hours after ictus • Cerebral edema (gyraJ swelling, sulcal obliteration) • May cause transient enhancement • May cause DWI restriction o

May mimic encephalitis, ischemic stroke, even neoplasm! o Follow-up scan shows resolution • Intracranial Hypertension, Idiopathic o Severe "pseudotumor cerebri" may cause diffuse brain swelling, papilledema, small ventricles o Look for "empty sella" plus dilated optic nerve sheaths indenting posterior globe o

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I Axial NECT shows diffuse brain swelling with loss of gray·while differentiation, diffuse sulcal effacement.

Small subdural hematoma is present ~.

Axial NECT in a padent with chronic hepadc encephalopathy and acute exacerbation shows diffuse cerebral edema, obliterated sulci, and effaced gray-while

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(Left) Axial NEeT shows perfeclly isodense subdural hematomas ~ same attenuation as cortex. All sulci are obliterated except one where CSF is seen in a sulcus displaced away Irom inner table ffi (Right) Axial NECT shows absence of visualized cerebral aqueduct ~ with enlarged 3rd, lateral ventricles and diffuse brain swelling. "Blurred" margins of lateral ventricles indicate transependymal CSF flow.

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Meningitis (Left) Axial NECT shows sulcal ell a cement over /elt convexity (contrast with normal-appearing right sulci) secondary to pyogenic meningitis &. Asymmetric involvement is unusual. (Right) Axial TlWI MR shows basal cisterns sulci I:llI appear effaced because they are lilled with isointense acute blood, not normal hypointense CSF Note acute obstructive hydrocephalus with blood-fluid levels in dilated lateral ventricles

Metastases, Skull and Meningeal (Left) Axial FlAIR MR in a patient with prostate cancer, headaches, shows normal right-sided sulci, thickened dura and infiltrated sulci m over entire left hemisphere. (Right) Coronal T I C+ MR in a patient with viral encephalitis shows diffuse right hemisphere swelling, especially temporal lobe. All surface sulci are obliterated. Note subIa/cine herniation from mass effect

I 4 14

Aneurysmal Subarachnoid Hemorrhage

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EFFACED SULCI, GENERALIZED

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cortical/subcortical lesions

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with PRES. (Right) Axial T2WI MR obtained after status epilepticus shows temporal lobe (and, to a lesser extent, parietal lobe) gyral hyperintensity CO> and mass effect mimicking encephalitis. Cyral swelling has effaced adjacent sulci.

Intracranial

Hypertension,

Idiopathic (Left) Axial T2WI MR shows dilated optic nerve sheaths elevation of optic nerve head liB Suprasellar cistern, sylvian fissure are small; superficial sulci almost effaced. (Right) Axial NECT in

a patient

with

right

arm/leg weakness 24 hours after left carotid endartereclOmy, shows swollen gyri with generalized decrease in left hemispheric sulci. Note hypodense parietal whitemaller=:l.MR

showed hyperintense cortex/while matle" decreased MTT

I 4 15

EFFACED SULCI, FOCAL

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DIFFERENTIAL DIAGNOSIS Common • Cortical Contusion • Cerebral Ischemia-Infarction, Acute • Spontaneous Intracranial Hemorrhage • Subdural Hematoma • Epidural Hematoma • Neurocysticercosis Less Common • Primary CNS Neoplasm o Meningioma o Oligodendroglioma o Ganglioglioma o Diffuse Astrocytoma, Low Grade o DNET o Pleomorphic Xanthoastrocytoma • Metastases, Parenchymal • Metastases, Skull and Meningeal • Abscess • Meningitis • Focal Cortical Dysplasia • Tuberous Sclerosis Complex • Thrombosed Cortical Vein(s) Rare but Important • Extra-Axial Empyema • Meningioangiomatosis • Superficial Siderosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Focal = one or several sulci (not hemisphere or whole brain) • Key concept: Is sulcal effacement caused by lesion within sulcus itself or underlying gyrus? o Intra- vs. extra-axial causes o Parenchymal> > sulcal disease • Imaging o Sulcal, gyral masses can be isodense on NECT, isointense on Tl-weighted MR difficult to detect!! o CECT, T2WI, FLAIR, Tl C+ scans most helpful

I 4 16

Helpful Clues for Common Diagnoses • Cortical Contusion o History of closed head injury o Heterogeneous hyper-/hypodense swollen gyri

Look for focal traumatic SAH adjacent to contusions • Cerebral Ischemia-Infarction, Acute o Cortical branch occlusion - gyral swelling o Difficult to see on ECT, Tl/T2WI o DWI helps distinguish ischemia (restricts) from neoplasm (usually doesn't) • Spontaneous Intracranial Hemorrhage o Children/young adult • Vascular malformation, venous occlusion, drug abuse o Middle-aged, older adults • Amyloid angiopathy, hypertension • Hemorrhagic neoplasm (metastasis, o

GBM)

• Subdural Hematoma o Usually crescentic, spreads over hemisphere - more generalized sulcal effacement o Occasionally focal, mimics EDH • Epidural Hematoma o Focal, biconvex extra-axial hematoma o Severe compression of underlying sulci o Mimics: Plasmacytoma, extra-medullary hematopoiesis, etc. • Neurocysticercosis o NCC cysts typically in subarachnoid spaces, depths of sulci o Intense pial inflammatory reaction may efface sulci Helpful Clues for Less Common Diagnoses • Primary CNS Neoplasms o Any cortical, subcortical neoplasm causes local mass effect, expanded parenchyma/compressed sulci o Age, history helpful • Child, young adult with longstanding seizures: Ganglioglioma (cyst, Ca++ common), DNET ("bubbly" appearance), low grade astrocytoma • Adult: Meningioma (dural-based, often Ca++), oligodendroglioma (Ca++ common, variable enhancement), PXA (look for "dural tail") • Metastases, Parenchymal o May cause focal mass, variable edema o Almost always enhances • Metastases, Skull and Meningeal o Dural-based, usually isodense/isointense with brain o Look for skull lesions

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• Abscess o Gray-white junction common site o Early stage (cerebritis) typically does not enhance o Late cerebritis/capsule stages ring-enhancement o Sulci compressed but don't enhance unless meningitis also present o DWI shows restriction early, helps distinguish abscess from neoplasm • Meningitis o Diffuse> focal, symmetric> asymmetric o Rarely affects solitary sulci; multiple adjacent sulci typically involved o FLAIR, Tl C+ stans best for detecting subtle disease • Focal Cortical Dysplasia o History of longstanding seizures o Perisylvian most common location o Follows gray matter on all sequences (occasionally slightly hyperintense on FLAIR) o Does not enhance o MRS usually normal • Tuberous Sclerosis Complex o Cortical tubers expand gyri, blur gray-white interface o Cortical/subcortical hyperintensity on FLAIR, T2WI o Tubers typically don't enhance o Taylor-type cortical dysplasia • Considered "forme fruste" of TSC • Solitary tuber • Caution: Can mimic neoplasm!

Cortical

Contusion

• Thrombosed Cortical Vein(s) o Usually occurs with dural sinus occlusion o May be isolated, solitary o Clinically devastating if vein of Labbe occluded o Can mimic hemorrhagic neoplasm/stroke/vascular malformation o T2* scan (GRE, SWI) helpful • Petechial hemorrhage in cortex ± focal SAH • Look for occluded dural sinus • Look for "cord-like" blooming in thrombosed vessel Helpful Clues for Rare Diagnoses • Extra-Axial Empyema o Look for sinusitis, mastoiditis ± underlying meningitis o Subdural> > epidural • Meningioangiomatosis o Usually child/young adult with seizure o Consider MA if calcified cortical lesion ± cysts o Typically hypointense "serpentine" cortical lesion o Enhances o May extend along PVSs, mimic neoplasm • Superficial Siderosis o History of repeated SAH helpful but not always present o Serpentine pial/cortical hypointensity on T2* scan> mass-like lesion o Posterior fossa> supratentorial brain

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Acute

I Axial NEG scan shows a left frontal hyperdensity with surrounding hypodensily typical of cortical contusion. Note effaced frontal sulci from focal mass effect.

Axial TIWI MR in patient "found down" several hours after "doing cocaine" shows a subtle, mostly isointense mass with adjacent sulcal effacement. Acute

=

drug·reJaled

cortical

inFarct.

4 17

EFFACED SULCI, FOCAL

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Spontaneous

II

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(Left) Axial T1 WI MR in 68 yo man with sudden onset of

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right-sided weakness shows

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mostly isoinlense cortical/subcortical mass 6> effacing adjacent sulci. T2 showed numerous peripherally-located microbleeds consistent with amyloid angiopathy. (Right) Axial NECT shows almost perfectly isodense right posterior

frontal mass

=.

Only indication of presence of mass is focal effacement of the underlying sulci. This is an easy lesion to miss.

"c '"

:J .:.; (f)

(Left) Axial NECT shows effacement of left posterior frontal sulci by calcified mass (Right) Coronal FLAIR MR shows inhomogeneously hyperintense left temporal lobe mass that infiltrates hippocampus, compressing temporal horn and effacing the collateral sulcus (compare with normal right side).

=-

=

(Left) Axial T1 WI MR shows hypointense left posterior parietal cortical/subcortical mass ~ with adjacent sulcal effacement. Mass was hyperintense on T2WI, FLAIR. WHO grade II fibrillary astrocylOma was found at surgery. (Right) Axial T1WI MR shows slightly "bubbly"

cOrLical-based mass ~ with focal gyral expansion, sulcal effacement.

I 4 18

Intracranial

Hemorrhage

EFFACED SULCI, FOCAL

(fl

;><"

c:

III

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Q.

to ....• III

(Left) Coronal T2WI MR in a 22 year old with longstanding temporal lobe epilepsy shows hyperintense cortically based mass 81 with adjacent sulcal compression. (Right) Axial T1 WI MR in a patient with known metastatic disease shows focal gyral expansion, sulcal effacement caused by

Tl isoinlenS€ metastasis.

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Abscess (Left) Axial T1 WI MR shows diffusely thickened, infiltrated inhomogeneously hypointense skull with adjacent dural-based mass 81. Note focal effacement of adjacent sulci. (Right) Axial NECT shows hypodense mass at gray-white junction that showed ring-like enhancement following contrast administration.

=

Thrombosed

Cortical

Vein(s) (Left) Axial FLAIR MR shows gyral swelling, subarachnoid hemoffhage causing focal sulcal hyperintensity T2' scan showed isolated cortical vein thrombosis. (Right) Axial FLAIR MR shows cortical/subcortical mass with effaced sulci,

=.

hypoinlense

area

!3iJ

suggestive of calcification. Lesion enhanced with contrast.

I 4 19

en c ~

INTERHEMISPHERIC

FISSURE CYSTS

Q)

~

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DIFFERENTIAL DIAGNOSIS

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Common • Pineal Cyst Less Common • Callosal Dysgenesis • Neurocysticercosis • Arachnoid Cyst Rare but Important • Holoprosencephaly (HPE) • Medial Atrial Diverticulum • Atretic Cephalocele • Dermoid Cyst • Epidermoid Cyst • Tumor-Associated Cysts • Aicardi Syndrome

c

Helpful Clues for Common Diagnoses • Pineal Cyst o Glial-lined intrapineal cyst located in pineal recess o Common (23% of healthy adults) o Multiple small « 2 mm) or larger confluent cysts o Usually isointense with CSF on 1'1-, T2WI; FLAIR variable o Wall thickness < 2 mm o Smooth rim-enhancement typical o Thick/nodular enhancement may be indistinguishable from pineocytoma • Truly cystic pineocytomas are rare • Some pineal cysts may have variant appearance, may even hemorrhage (cyst apoplexy)

lU

ESSENTIAL INFORMATION

I 4 20

Key Differential Diagnosis Issues • Anatomic sublocation key o Pineal/quadrigeminal region • Is it pineal cyst or cystic-appearing pineal tumor (e.g., pineocytoma) • CSF-like: Arachnoid cyst, epidermoid cyst, medial atrial diverticulum o Superior interhemispheric fissure • Most common: Cyst associated with callosal dysgenesis, holoprosencephaly; neurocysticercosis • Less common: Arachnoid cyst, atretic cephalocele, Aicardi syndrome o Posterior interhemispheric fissure • More common: Holoprosencephaly, medial atrial diverticulum • Less common: Epidermoid cyst o Anteroinferior interhemispheric fissure • Neurocysticercosis • Dermoid cyst (more common in midline) • Epidermoid cyst (less common in midline) • Two morphologically distinct types of interhemispheric CSF-containing cysts o Interhemispheric cyst associated with callosal dysgenesis or holoprosencephaly o Parasagittal cyst unassociated with callosal dysgenesis • Arachnoid cyst, medial atrial diverticulum • Tumor-associated cysts (macroadenoma, meningioma)

Helpful Clues for Less Common Diagnoses • Callosal Dysgenesis o 3rd ventricle open dorsally o Two types of agenesis with interhemispheric cyst • Type 1 (most common): Cyst is diverticulum of lateral ventricle, density/signal like CSF, ependymal-lined • Type 2: Multilocular/septated cysts within/adjacent to midline that do not communicate with ventricles, typically hyperdense/hyperintense to CSF • Neurocysticercosis o "Racemose" cysts> solitary cysts • Convexity sulci • Anteroinferior interhemispheric fissure • Suprasellar/basal, quadrigeminal cisterns • Arachnoid Cyst o Only S% of ACs occur in parasagittal region/interhemispheric fissure • Usually are convexity ACs that extend medially • Most are small, unilateral, asymptomatic o Large/symptomatic ACs in interhemispheric fissure rare • Typically not associated with callosal dysgenesis • May also "straddle" falx, extend equally on each side • Do not communicate with ventricular system • May cause progressive lower extremity weakness

INTERHEMISPHERIC

Helpful

Clues for Rare Diagnoses

• Holoprosencephaly (HPE) o Alobar HPE • Central monoventricle opens to large dorsal CSF-filled cyst • Cyst wall comprised of telencephalic roof plate, tela choroidea remnants o Semilobar HPE • May occur with large dorsal CSF space • Medial Atrial Diverticulum o Local herniation of posteromedial lateral ventricle o Typically associated with severe, long-standing hydrocephalus o Massive ventricular enlargement - uni- or bilateral pulsion diverticulae of inferomedial atrial wall o CSF-filled pouch herniates medially into quadrigeminal cistern • Large medial atrial diverticulae may extend inferiorly through incisura into posterior fossa • Atretic Cephalocele o T2 hyperintense subscalp mass extends through midline calvarial defect o ± Primitive falcine vein • Dermoid Cyst o Congenital inclusion cyst o Fat & calcification o Location • Midline> off-midline • Frontonasal, sella/parasellar, quadrigeminal cistern

,..c:

(IJ

FISSURE CYSTS

Look for fatty droplets in cisterns, sulci, ventricles • Epidermoid Cyst o 4-9x more common than dermoid cyst o

BUT • Off-midline> midline • Rarely arises in interhemispheric fissure o May adhere to surrounding structures like ACA, make resection difficult o Resembles CSF on CT, MR • Often very slightly hyperintense to CSF • Doesn't suppress on FLAIR • Restricts on DWI • Insinuates/infiltrates along subarachnoid cisterns • Tumor-Associated Cysts o Most common with pituitary macroadenoma, meningioma o Trapped pools of CSF (subarachnoid space) or interstitial fluid (perivascular spaces) • Aicardi Syndrome o X-linked dominant o Associated with broad spectrum of cerebral malformations (e.g., Dandy-Walker continuum) o Classic triad • Infantile spasms • Chorioretinallacunae • Agenesis CC ± interhemispheric cyst o Choroid plexus cysts, papillomas Other

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Essential Information

• FLAIR,DWI helpful to distinguish CSF-like cysts from other types

Pineal Cyst

I Sagiltal T7 c+ MR shows a unilocular cystic pineal gland with r;m-enhancement Note that cyst fluid is slighlly hyperintense to CSF in adjacent

=.

quadrigeminal/superior cerebellar cistern.

Sagiltal T2WI MR shows multiple tiny cysts in the pineal gland

4 21

INTERHEMISPHERIC

(/)

c ~

FISSURE

CYSTS

Q)

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w

Callosal Dysgenesis

Callosal Dysgenesis

Neurocysticercosis

Neurocysticercosis

Arachnoid Cyst

Arachnoid Cyst

(Left) Sagittal T2WI MR shows a dysgenetic corpus callosum EJ with a large Barkovich type 7 interhemispheric cyst (Right) Axial CECT shows callosal dysgenesis with widely-spaced, parallel, nonconverging, lateral ventricles Barkovich type 2b multilocular cysts EJ are slightly hyperdense and do not communicate with ventricles.

=.

=.

C III

~ CO "0

c

III

(Left) Axial T2WI MR shows NCC cysts in the anleroinferior interhemispheric fissure I::] as well as suprasellar cistern EJ. (Right) Sagittal T2WI FS MR shows multiple interhemispheric cysts in a patient with known neurocyslicercosis. (Courtesy r. Bravo, MOJ.

=

=

(Left) Axial FLAIR MR shows a CSF-like mass over the leFt cerebral convexity that extends medially to the interhemispheric fissure E1. Iligh signal intensity Foci lateral to cyst are small chronic subdural hematomas. (Right) Sagittal TlWI MR shows large CSF-like mass extending From supravermian cistern ED into cavum velum inlerposilUm

=..

flauening

internal

cerebral veins ~.

I 4 22

INTERHEMISPHERIC

FISSURE CYSTS

(J)

""c: III

::l Co

..• OJ

Medial Atrial Diverticulum

III

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(Left) Sagittal T2WI MR shows a semi/abar variant with a large dorsal cyst open to monoventricle

m

~ ... OJ ,

~

(Right) Axial NECT shows moderate but symmetric enlargement of both lateral ventricles. A pouch of CSF SlI protrudes medially from the right lateral ventricle ~ into the interhemispheric fissure, quadrigeminal,

and

superior cerebellar cisterns.

OJ

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3

Dermoid Cyst

C/l

(Left) Sagittal T2WI MR shows a hyperintense atretic parietal cephalocele I:] extending through the midline

cranium

bifidum.

Note persistent primitive falcine vein [;8 (Right) Axial NECT shows very hypodense

mass in the midline anleroinferior fissure. Note calcification

hemispheric the marginal

=.

Tumor-Associated Cysts (Left) Axial T2WI MR shows a hyperintense extra·axial mass in the posteroinferior interhemispheric fissure that displaces the occipital lobe anteriorly and erodes the skull posteriorly SlI. (Right) Axial T2WI MR shows a pituitary macroadenoma

=

=

with superior extension

into

the 3rd ventricle, anterior extension into the interhemispheric fissure. Note trapped CSF-likc pools of fluid SlI around the tumor representing nonneoplastic tumor-associated cysts.

I 4 23

CPA MASS, ADULT

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DIFFERENTIAL DIAGNOSIS Common • Vestibular Schwannoma Less Common • Meningioma, CPA-lAC • Epidermoid Cyst, CPA-lAC • Aneurysm, CPA-lAC • Arachnoid Cyst, CPA-lAC • Metastases, CPA-lAC Rare but Important • Neurofibromatosis 2, CPA-lAC • Sarcoidosis, CPA-lAC • Choroid Plexus Papilloma, CPA • Lipoma, CPA-lAC • Ependymoma, CPA • Pseudotumor, Intracranial • Schwannoma, Facial erve, CPA-lAC • Schwannoma, Jugular Foramen • Hemangioma, lAC • Neurenteric Cyst

ESSENTIAL INFORMATION

I 4 24

Key Differential Diagnosis Issues • Idealized imaging protocol in evaluating CPA mass lesions o Tl C+ fat-saturated MR is gold standard • Fat-saturation differentiates lipoma from vestibular schwannoma • Add DWI for possible epidermoid • Add GRE for aneurysm wall clot & calcification; tumor calcifications o T2 thin-section, high-resolution, MR gives more surgical data when vestibular schwannoma diagnosed • Amount of CSF cap in lateral lAC • Assessment of relationship to cochlear nerve canal • If small schwannoma, nerve of origin • Knowledge of relative incidence of lesions key in cerebellopontine angle o Vestibular schwannoma - 90% all CPA-lAC masses o Meningioma, epidermoid cyst, aneurysm, arachnoid cyst together represent - 8% all CPA-lAC masses o All other diagnoses in differential list - 2% of CPA-lAC masses

Helpful Clues for Common Diagnoses • Vestibular Schwannoma o Morphology: Ovoid intracanalicular mass (lAC); "Ice cream on cone" shape (CPA-lAC) o Tl C+ MR: Enhancing ± intramural cysts Helpful Clues for Less Common Diagnoses • Meningioma, CPA-lAC o Morphology: "Mushroom" dural-based mass capping lAC asymmetrically o Tl C+ MR: Enhancing ± dural "tails" ± CSF-vascular cleft if CPA component is larger • 25% of CPA meningiomas have extension/dural tail into lAC • Epidermoid Cyst, CPA-lAC o Morphology: Insinuating ± scalloping brainstem margin o Tl C+ MR: Nonenhancing; may be difficult to see o DWI: Restricted diffusion (high signal) makes diagnosis • Aneurysm, CPA-lAC o Morphology: Ovoid or fusiform; rarely lAC o Tl & T1 C+ MR: Complex signal mass from wall calcification, clot & flow o MRA, CTA, or angiography sort out diagnosis • Arachnoid Cyst, CPA-lAC o Morphology: Fills cistern with rounded margins o Imaging • Tl C+ MR: No enhancement • FLAIR attenuates • DWI: No restricted diffusion • Metastases, CPA-lAC o Morphology: Irregular, invasive margins o Tl C+ MR: Single or multiple enhancing masses in CPA area • 4 sites primarily involved: Flocculus, choroid plexus, arachnoid-dura, or pia Helpful Clues for Rare Diagnoses • Neurofibromatosis 2, CPA-lAC o Morphology: Bilateral ovoid lAC or "ice cream on cone" CPA-lAC masses o T1 C+ MR • Bilateral enhancing CPA-lAC masses pathognomonic of NF2 • Other schwannomas & meningiomas may be present

CPA MASS, ADULT

• Sarcoidosis, CPA-lAC o Laboratory: CSF lymphocytosis; t t blood angiotensin converting enzyme (ACE) o Morphology: En plaque or nodular dural lesion(s) o Tl C+ MR: Enhancing multifocal dural-based lesions • Choroid Plexus Papilloma, CPA o Morphology: Dumbbell shape with 4th ventricle and CPA cistern components • Pear-shaped if begins in foramen of Luschka o Tl C+ MR: Avidly enhancing mass in 4th ventricle projecting through foramen of Luschka into CPA cistern • Lipoma, CPA-lAC o Morphology: Ovoid if lAC; CPA lesion may be broad-based against brainstem oCT: Fat-density lesion of CPA ± lAC ± inner ear o T1 MR: High signal lesion disappears with fat-saturation o Caveat: If Tl C+ without fat-saturation, may be mistaken for vestibular schwannoma • Ependymoma, CPA o Morphology: Irregular soft tumor squeezes out through 4th ventricle foramen of Luschka into CPA cistern • Tumor margins amorphous oCT: Calcifications in 50% o Tl C+ MR: Heterogeneous enhancement of solid tumor components

Vestibular

•

•

•

•

•

• Marginal enhancement of tumor cyst wall Pseudotumor, Intracranial o Morphology: En plaque o Tl C+ MR: Thickened, enhancing dura o Caveat: May mimic meningioma, sarcoidosis or metastatic disease Schwannoma, Facial Nerve, CPA-lAC o Morphology: CPA-lAC mass with "labyrinthine tail" oCT: Labyrinthine segment CN? may be enlarged o Tl C+ MR: Enhancing tubular mass in CPA-lAC and labyrinthine segment CN? o Caveat: If not labyrinthine segment CN? involvement, cannot differentiate from vestibular schwannoma Schwannonla, Jugular Foramen o Tl C+ MR: Enhancing mass arising from jugular foramen • Mass projects cephalad into CPA cistern Hemangioma, lAC o Morphology: Ovoid lAC mass with punctate calcifications oCT: Punctate calcifications in lAC mass o Tl C+ MR: Enhancing lAC mass with focal low signal foci (calcifications) Neurenteric Cyst o Morphology: Rounded ovoid mass in prepontine cistern o MR: Intermediate to high signal Tl prepontine mass o Caveat: Tl increased signal differentiates from epidermoid cyst

Meningioma,

Schwannoma

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CPA-lAC

I Axial T1 C+ MR ,eveals enhancing mass filling the CPA & internal auditory canal 81. Note the cochlear

=

nerve canal is involved hearing preservation

=

difficult.

making resection with

Axial T1 C+ FS MR reveals an enhancing dural-based

mass centered over the lAC but with minimal lAC

=.

involvement The shape and the associated dural tail meningioma diagnosis.

B make

4 25

CPA MASS, ADULT

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Epidermoid

Cyst, CPA-lAC

Aneurysm,

CPA-lAC

Arachnoid

Cyst, CPA-lAC

Metastases,

CPA-lAC

Sarcoidosis,

CPA-lAC

(Left) Axial TI WI MR shows a low signal mass in the right CPA cistern that insinuates and enlarges the Foramen of Luschka and scallops the ventral cerebellar hemisphere 81. (Right) Axial TI C+ MR demonstrates a large enhancing distal vertebral artery aneurysm projecting up into the CPA cistern and compressing the area where CN? and CN8 exit the brainslem ~.

=

=

C

•.. III

aJ

"0 C III

(Left) Axial T2WI FS MR shows a high signal lesion in low CPA cistern. Note the anterior displacement of proximal CN8 by arachnoid cyst 81. The high signal results From absence of CSF (Jaw. (Right) Axial TI C+ FS

=

MR reveals an in homogeneously enhancing metastatic focus arising from dura along the prepontine

cistern. This metastasis reaches the anterior margin of the porus acuslicus

=.

Neurofibromatosis (Left) Axial T1 C+ MR shows bilateral enhancing CPA-tAC schwannomas The leFt

=.

schwannoma involves the intra temporal facia! nerve HJ indicating it is mosllikely a facial nerve scl1wannoma. (RighI) Axial TI C+ MR shows heaped up, dural-based, sarcoid deposit in right CPA that enters the internal auditory canal !l::I. Meckel cave is also aFFected81. This lesion

=

mimics

I 4 26

meningioma.

2, CPA-lAC

CPA MASS, ADULT

Ul

c: " III

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Co III

.., lipoma,

III

CPA-lAC (Left) Axial TI C+ MR reveals a pear-shaped inhomogeneously enhancing papilloma projecting from the lateral recess of the 4th ventricle through the foramen of Luschka into the low CPA cistern 82. (Right) Axial T1WI MR shows a

=

varianllhree-part

lipoma

=-

affecting the CPA cistern high anterior jugular foramen 82 and the vestibule of the inner ear P.:Z. No surgery is done for these lesions.

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3

Intracranial

CJ>

(Left) Axial TI C+ MR demonstrates an aggressive mixed cystic-solid enhancing ependymoma of the right CPA cistern 4th ventricle 8l and cerebellar hemisphere 1J:!ll. (Right) Axial T1 C+ MR demonstrates an extensive area of enhancing dural thickening along the right low CPA cistern. The intracranial pseudotumor also involves the subjacent jugular foramenB.

=-

=

Schwannoma,

Facial Nerve, CPA-lAC

Schwannoma,

Jugular Foramen (Left) Axial T I C+ MR shows

a variant facial nerve schwannoma with enhancing CPA-lAC

component II] extending into the geniculate ganglion

82. Note associated arachnoid cystlJ:!ll. (Right) Coronal TI + MR reveals a schwannoma projecting cephalad from the jugular foramen 82 into the CPA cistern. Note the normal lAC IJ:!ll is at the level of upper margin of the tumor.

rs

=

I 4 27

CYSTIC CPA MASS

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DIFFERENTIAL DIAGNOSIS

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Less Common • Vestibular Schwannoma with Intramural Cyst(s) • Neurocysticercosis, CPA • Hemangioblastoma • Large Endolymphatic Sac Anomaly (IP-2) Rare but Important • Vestibular Schwannoma with Arachnoid Cyst • Schwannoma, Facial Nerve, CPA-lAC with Cyst • Neurenteric Cyst • Schwannoma, Jugular Foramen with Intramural Cyst

ESSENTIAL INFORMATION

I 4 28

• Also sorts out solid and cystic components of lesions • May help with associated cranial nerve and arterial anatomy Helpful Clues for Common Diagnoses • Epidermoid Cyst, CPA-lAC o Congenital rest of epithelial tissue in CPA o Imaging • Insinuating ± scalloping brainstem margin • Tl C+ MR: Nonenhancing, cystic appearing; may be difficult to see • DWI: Restricted diffusion (high signal) makes diagnosis • Arachnoid Cyst, CPA-lAC o Congenital lesion resulting from failure of embryonic meninges to merge with cyst between split in arachnoid membrane o Imaging: Fills cistern with rounded margins • Tl C+ MR: No enhancement • Other MR: FLAIRattenuates; DWI: No restricted diffusion Helpful Clues for Less Common Diagnoses • Vestibular Schwan noma with Intramural Cyst(s) o Vestibular schwannoma may have either intramural or extramural (arachnoid cyst) cysts o Imaging • Solid CPA-lAC mass with intramural cysts • Tl C+ MR: Enhancing solid tumor component ± intramural cysts (common) ± arachnoid cyst (rare) • Neurocysticercosis, CPA o Intracranial infection caused by pork tapeworm (Taenia solium) o Imaging • Cysts with "dots" inside • Appearance varies with stage • Tl C+ MR: Cysts with enhancing thin or thick wall • Hemangioblastoma o Adult with intra-axial posterior fossa mass abutting pia o Imaging • Cerebellar cystic & solid tumor • Tl C+ MR: 60% of tumors with solid enhancing & cystic components (40% solid only)

CYSTIC CPA MASS

CJl

'"

c:

• Large Endolymphatic Sac Anomaly (IP-2) o Bilateral congenital S HL that appears in child with cascading hearing loss pattern o Most common congenital imaging abnormality o Imaging • CT: Enlarged bony vestibular aqueduct • T2 high-resolution MR: Enlarged endolymphatic sac + mild cochlear aplasia (modiolar deficiency, bulbous apical turn, scalar chamber asymmetry) Helpful Clues for Rare Diagnoses • Vestibular Schwannoma with Arachnoid Cyst o Vestibular schwannoma with extramural (arachnoid cyst) cyst o Neuro-otologist refer to as "herald cyst" o Imaging • CPA-lAC mass with extramural cyst • Tl C+ MR: Enhancing solid tumor component rare ± arachnoid cyst • Schwannoma, Facial Nerve, CPA-lAC with Cyst o Rare CPA-lAC mass with "labyrinthine tail" involving labyrinthine segment of facial nerve canal o Often present with hearing loss before facial nerve symptoms o Imaging • CT: Labyrinthine segment CN? may be enlarged

Epidermoid

• Tl C+ MR: Enhancing tubular mass in CPA-lAC & labyrinthine segment of facial nerve; intramural or extramural cyst visible • Neurenteric Cyst o Incidental rounded to ovoid mass in prepontine cistern o Imaging • MR shows intermediate to high signal T1 prepontine mass • Schwannoma, Jugular Foramen with Intramural Cyst o Presents with some mixture of 9-12 cranial neuropathy o Imaging • Bone CT: Enlarged sharply marginated jugular foramen • Tl C+ MR shows enhancing mass with intramural cysts arising from jugular foramen & projecting superomedially into CPA cistern often with brainstem compression

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=

Axial T7 C+ MR reveals a low signal epidermoid cyst lhat insinuates into foramen of Luschka and cerebellar hemisphere E:I. OWl MR sequence would show restricted diffusion.

Axial T7 C+ FS MR demonstrates a right CPA cistern arachnoid cyst displacing the proximal facial and vestibu/ocochlear nerves anteriorly H2.

=

I 4 29

CYSTIC CPA MASS

(/)

E ell

en

u -0

·0

Vestibular

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~ U
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Cyst(s)

compresses the brainstem

and cerebellum. (Right) Axial T1 C+ MR reveals the inFerior aspect of a large enhancing vestibular schwannoma in the leFt CPA cistern. An unusually prominent intramural cyst is present 81.

a. (f)

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X

w

Vestibular

Schwannoma with Intramural Cyst(s)

(Left) Axial T1 C+ MR shows a large enhancing vestibular schwannoma projecting from the lAC 1:1'1 into the CPA. The tumor has a large intramural cyst 81 &

ell

u

Schwan noma with Intramural

C III

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demonstrates a cystic mass in the right cerebellopontine angle cistern with an

enhancing wall 1:1'1. Adjacent enhancing, thickened

meninges are also seen 9. (Right) Coronal T1 C+

rs

MR shows multiple cysts in the right cerebellopontine angle cistern causing

-=

mass effect on the brainstem.

Secondary hydrocephalus present.

is

Hemangioblastoma (LeFt) Axial T1 C+ FS MR shows an inlracerebelfar mixed cystic-solid hemangioblastoma projecting into the leFt cerebellopontine angle cistern area. The solid nodule is avidly enhancing 1:1'1 (Right) Axial T2WI MR

reveals an intra cerebellar

I 4 30

high signal hemangioblastoma projecting into the cerebellopontine angle cistern area. Contrast is required to define enhancing nodule if present.

Hemangioblastoma

CYSTIC CPA MASS

CJl

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Cyst (Left) Axial TlWI MR shows a large endolymphatic sac within the posterior wall of the T-bone. CT would reveal a large bony vestibular aqueduct in this patient with large endolymphatic sac anomaly. (Right) Axial T2WI MR shows a vestibular schwannoma projecting from the lAC into the CPA cistern. An associated arachnoid cyst is visible compressing the brainslem & 4th ventricle ~ .

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Schwannoma, Jugular Foramen with Intramural Cyst

Schwannoma, Jugular Foramen with Intramural Cyst (Left) Axial T I C+ MR demonstrates an ovoid enhancing mass in low CPA cistern =:J. Multiple intramural cysts suggest the diagnosis of schwannoma.

Extension into jugular foramen is evident 81. (Right) Axial T2WI FS MR reveals large sharply marginated lesion in the jugular foramen E2. High signal mass projects medially into the low CPA cistern where it compresses the brainstem

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ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Anatomy o Extensive CSF space along ventral & lateral pons, dorsal to clivus (a.k.a, pontine cistern) o Bounded superiorly by interpeduncular cistern, inferiorly by subarachnoid space of spinal cord, & continuous about medulla with cerebellomedullary cistern • Many abnormalities, often from transpatial processes

I 4 32

Assess real vs. artifact in other planes Minimize TOF losses: Use short TE, image parallel to flow, acquire thicker slices Dolichoectasia (Vertebrobasilar) o Older patients o Look for ASVDin other vessels o Ectasia often extends into branches o May have significant mass effect on pons Fusiform Aneurysm, ASVD o Long segment fusiform arterial dilatation o Involves long nonbranching segments o Calcifications common o Lumen enhances strongly, clot does not Meningioma o Clival dural-based enhancing mass o Infratentorial (8-10%): CPA most common o Causes cranial neuropathies or ataxia Metastases, Skull and Meningeal o Enhancing lesion(s) with skull/meningeal destruction/infil tra tion o Manifestations: Smooth thickening, nodularity, loculation, fungating masses o Image entire neuraxis! o

DIFFERENTIAL DIAGNOSIS

Helpful Clues for Common Diagnoses • CSF Flow Artifact o MR artifacts divided into 2 categories: Time-of-flight effects & turbulent flow o Worsens with thinner slices, longer TE, and imaging perpendicular to flow

•

•

•

•

Helpful Clues for Less Common Diagnoses • Epidermoid Cyst o Usually extends medially from CPA cistern o Lobulated, irregular, insinuating CSF-like mass o Doesn't completely suppress on FLAlR; restricts on DWI • Chiari 2 ("Creeping Cerebellum") o Small posterior fossa with low torcular herophili o Cerebellar hemispheres/tonsils herniate anteriorly - "creeping" o Pons, cranial nerve roots often elongated • Exophytic Brainstem Glioma, Pediatric o Nonenhancing mass markedly expanding pons; may engulf basilar artery o Infiltrative have poor survival o Focal are uncommon, better prognosis • Pituitary Macroadenoma (Giant) o No distinct pituitary gland o Bone CT shows benign bony margins o Early intense but heterogeneous CTST+ o Dural "tail" may mimic meningioma • Neurocysticercosis o Cisterns> parenchyma> ventricles o Basal cistern cysts may be racemose o Cysts variable, typically 1 cm, range from 5-20 mm, contain a 1-4 mm scolex

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85% o

Bilateral subdural fluid collections in 15%

Helpful Clues for Rare Diagnoses

• Inflammatory Mass o Tuberculosis • Basilar meningitis, pulmonary TB • Thick basilar exudate ± tu berculomas/ abscesses o Fungal Diseases • Blastomycosis, coccidiomycosis, histoplasmosis, candidiasis • Meningeal enhancement, multiple enhancing brain lesions o Neurosarcoid • Classically infiltrates dura, leptomeninges, basal cisterns • Solitary or multifocal CNS mass(es) ± abnormal CXR • Clival Neoplasms o Chordoma, Clivus • Destructive midline mass centered in clivus with high T2 signal intensity • Sagittal images show tumor "thumb" indenting anterior pons o Chondrosarcoma, Skull Base • Arises from petro-occipital fissure • May extend posteriorly into prepontine cistern

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Axial FLAIR MR reveals a hyperintense artifact due to CSF turbulent flow. Also note sulcal hyperintensity from subarachnoid hemorrhage H1

• •

•

•

•

• Hyperintense on T2WI, enhances strongly but heterogeneously • Chondroid mineralization on CT (50%) o Plasmacytoma, Skull Base • Solitary intraosseous osteolytic soft tissue mass with non-sclerotic margins • Peripherally displaced osseous expansion/fragmentation may be seen o Nasopharyngeal Tumor (Invading Clivus) • Often squamous cell CA arising from nasopharyngeal mucosal space • Multi-planar MR images best show invasion of clivus Schwannoma o T2 hyperintense, enhance Arachnoid Cyst o Extra-axial cyst follows CSF attenuation/signal o Suppresses completely with FLAIR;no DWI restriction Craniopharyngioma o 90% Ca++, 90% cystic, 90% enhance o May extend behind sella into posterior fossa Neurenteric Cyst o Round/lobulated nonenhancing, slightly hyperintense to CSF mass o Benign malformative endodermal CNS cyst Ecchordosis Physaliphora o Notochord remnant o Extends from clivus into prepontine cistern o Hyperintense on T2WI

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Metastases, Skull and Meningeal (Left) Axial TI C+ MR demonstrates extensive renal cell metastatic disease involving the clivus & overlying dura effacing the prepontine cistern Ea. (Right) Axial T I C+ MR shows a typical MR case of leptomeningeal seeding of

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(Left) Axial TI C+ MR shows thick enhancement in the subarachnoid space & along the pia /illing the prepontine cistern and extending into the le/tlAC 81. Diagnosis: Cocci meningitis. (Right) Axial TI C+ MR demonstrates fine linear enhancement along the pia from candida meningitis.

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Predominance of tumor mass in posterior fossa is unusual.

(Left) Sagiltal T7 WI MR reveals a well-delineated, slightly ovoid, lobulated mass that was hyperintense to CSF on all sequences. (Right) Axial T2WI FS MR shows a lobulated mass in prepontine cistern that indents pons is hyperintense to CSF.Note subtle dehiscence of clivus B from which lesion arose.

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ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Cisterna magna (CM) between medulla (anterior), occiput (posterior) (a.k.a., cerebellomedullary cistern) o Below/behind inferior vermis o Large medullary cistern masses may extend laterally, posteriorly into CM • Most common adult lesions are tonsillar-associated o Indirect (secondary effect on tonsil) > direct (lesion in tonsil) • MR and clinical information helps DDx

I 4 38

Helpful Clues for Common Diagnoses • Herniation Syndromes, Intracranial o Most often 2° to posterior fossa (PF) mass effect o Tonsils pushed down into CM o "Peg-like" configuration of tonsils o Tonsil folia usually oriented horizontally ~ become vertically oriented when herniated o 4th ventricle may obstruct, cause obstructive hydrocephalus • Chiari 1 o Pointed cerebellar tonsils "- 5 mm below foramen magnum o Posterior fossa (PF) usually normal size o Age-related tonsil descent below "opisthion-basion line" common

Treatment aim = restore normal CSF flow at foramen magnum (FM) • Chiari 2 o Small PF ~ contents shift j. o "Cascade" of tissue (vermis, not tonsil) herniates j. through FM o - 100% associated myelomeningocele • Dandy-Walker Continuum (DWe) o DWC a broad spectrum of cystic posterior fossa (PF) malformations o DW malformation: Large posterior fossa and large CSF cyst, normal 4th ventricle absent, lambdoid-torcular inversion o OW variant: Failure of "closure" of 4th Ventricle, vermian hypoplasia o Mega cisterna magna: Communicates freely with 4th ventricle, basal subarachnoid spaces o 2/3 have associated C Sand/or extracranial anomalies o

Helpful Clues for Less Common Diagnoses • Arachnoid Cyst o Sharply demarcated extra-axial cyst that follows CSF attenuation/signal o FLAIRsuppresses; no diffusion restriction o Size varies from a few mms to giant o Often asymptomatic, found incidentally o CPA location> CM • Ependymoma o Cellular ependymomas more common in children o Soft or "plastic" tumor squeezes out of 4th ventricle foramina into cisterns o Ca++ common (50%); ± cysts, hemorrhage o Sagittal imaging can distinguish origin as floor vs. roof of 4th ventricle o Heterogeneous Tl/T2 signal with mild to moderate enhancement • Meningioma o CM rare PF location (CPA, medullary cisterns more common) o CM meningiomas usually arise from occipital squamosa o Well-demarcated, lobulated/rounded enhancing mass with dural attachment o Hyperostosis, tumoral calcifications, t vascular markings • Metastasis o Linear or nodular meningeal enhancement o MR CSF flow may be helpful establishing location and degree of CSF obstruction

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Primary tumors include breast, lung, melanoma, prostate o Lymphoproliferative malignancy = lymphoma and leukemia o Primary CNS tumor seed basal cisterns (drop metastases) o Image entire neuraxis! • Intracranial Hypotension o Sagittal shows brain descent in 40-50% o Caudal displacement of tonsils in 25-75% o Diffusely intensely enhancing dura in 85% o Bilateral subdural fluid collections in 15% o Frequently misdiagnosed syndrome of headache caused by • intracranial CSF pressure from spontaneous spinal CSF leak o

Helpful Clues for Rare Diagnoses • Subependymoma o T2 hyperintense lobular, nonenhancing intraventricular mass o Arises from 4th ventricle floor, may extend posteroinferiorly into cisterna magna o More common in middle-aged, older adults 00.7% of intracranial neoplasms • Epidermoid Cyst o Lobulated, irregular, CSF-like mass with "fronds" insinuates cistern o FLAIRusually doesn't completely null; diffusion yields high signal restriction 00.2-1.8% of all primary intracranial tumors o Congenital inclusion cysts; rare malignant degeneration into squamous cell carcinoma

Herniation

Syndromes,

• Dermoid Cyst o Fat appearance: Use fat suppression sequence to confirm o With rupture find fat droplets in cisterns, sulci, ventricles with extensive MR enhancement possible from chemical meningitis o Rare: < 0.5% of primary intracranial tumors o Rupture can cause significant morbidity/mortality o Rare malignant degeneration into squamous cell carcinoma • Hemangioblastoma o Intra-axial posterior fossa mass with cyst, enhancing mural nodule abutting pia o Classified as meningeal tumor of uncertain histogenesis o Familial = von Hippel-Lindau o 7-10% of posterior fossa tumors • Neurenteric Cyst o Round/lobulated nonenhancing, slightly hyperintense to CSF mass o Most intracranial NECs found in posterior fossa o Benign malformative endodermal CNS cyst o Part of split spinal cord malformation spectrum; persistent neurenteric canal o Location • Thoracic (42%), cervical (32%) • Others: Lumbar spine, basilar cisterns, brain parenchyma • Anterior medullary, CPA cisterns> CM

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magnum

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and effacing the cisterna magna.

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Chiari 2

MASS

Dandy-Walker Continuum (DWC)

(Left) Sagittal T1WI MR shows caudal descent of cerebellar verm;an tissue and elongated 4th ventricle !:ll as well as callosal dysgenesis 81 and a small posterior fossa. (Right) Sagittal T1WI MR demonstrates markedly

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posterior

fossa with

huge cisterna magna cyst B:I in continuity with 4th ventricle. Note upwardly rotated superior vermian remnant 11].

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flattening

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the cervicomedullary junction extending caudally into the upper cervical canal. (Right) Sagittal T1 C+ MR shows enhancing tissue extruding through the foramen of Magendie, filling cisterna magna and causing enlarged cerebral aqueduct dilated 3rd ventricle 81.

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Metastasis (Left) Sagittal T1 WI MR demonstrates dural-based tumor with significant mass effect compressing and displacing the cerebellum. Note the /rapped CSF clefts !:ll. The tumor encroaches on cisterna magna. (Right) Axial T1 C+ MR shows a typical case of primary CNS lymphoma with subependymal tumor spread. Note a posterior fossa mass near the foramen of Luschka as well as a 2nd dural-based mass 81.

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(Left) Sagitlal TI C+ MR shows obliteration of the

suprasellar cistern

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Hemangioblastoma (Left) Sagitlal TI C+ MR demonstrates a mostly solid hemangioblastoma involving the cerebellar tonsils and effacing the cisterna magna. (RighI) Axial T f C+ MR shows a neurenteric cyst encroaching upon the cisterna magna EB Although most often these are located anteriorly, when large they may extend posteriorly as in this case.

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Common • Acquired Tonsillar Herniation • Dolichoectasia (Vertebrobasilar) • Chiari 1 • Chiari 2 • Diffuse Astrocytoma, Low Grade Less Common • Meningioma • Schwannoma • Ependymoma • Metastases, Intracranial, Other • Subependymoma • Hemangioblastoma • Intracranial Hypotension • Skull Base Masses o Chordoma, Clivus o Chondrosarcoma, Skull Base o Giant Invasive Pituitary Macroadenoma Rare but Important • Epidermoid Cyst • Dermoid Cyst • Syringomyelia • Neurenteric Cyst

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Foramen magnum (FM) is posterior skull base aperture in occipital bone o Transmits medulla oblongata, vertebral arteries & accessory nerves (CNll) • FM mass can be divided into intra-axial, extra-axial, & skull base masses • Cisterna magna is skull base cistern between medulla anteriorly & occiput posteriorly Helpful Clues for Common Diagnoses • Acquired Tonsillar Herniation o Secondary to posterior fossa mass effect or severe hydrocephalus o Tonsils pushed inferiorly, impacted into FM

Cisterna magna obliterated 4th ventricle may obstruct causing hydrocephalus • Dolichoectasia (Vertebrobasilar) o Dilated, ectatic vessels in older patient o Typically affects vertebrobasilar system o May mimic a PM mass o

o

I 4 42

• Chiari 1 o Small posterior fossa, crowded FM o Low-lying, pointed cerebellar tonsils; > 5 mm below FM • Chiari 2 o Complex malformation of hindbrain with lumbar myelomeningocele o Tissue herniates through FM behind upper cervical cord o Elongated, "straw-like" 4th ventricle o Associated with dural abnormalities, "beaked" tectum, "towering" cerebellum, dysgenic corpus callosum • Diffuse Astrocytoma, Low Grade o Primary astrocytic brain tumor with intrinsic tendency for malignant progression o 50% of brain stem "gliomas" are low-grade astrocytoma; occur in pons & medulla of children o T2 hyperintense mass; ± enhancement Helpful Clues for Less Common Diagnoses • Meningioma o Extra-axial, enhancing, dural-based mass with dural "tails" o Often occur along clivus with extension through FM • Schwannoma o Benign encapsulated nerve sheath tumor composed of differentiated neoplastic Schwann cells o Enhancing extra-axial mass; T2 hyperintense o Often occur along cranial nerves at skull base with extension into FM • Ependymoma o Soft or "plastic" tumor, squeezes out through 4th ventricle foramina 02/3 infratentorial, 4th ventricle o Heterogeneously enhancing 4th ventricle mass • Metastases, Intracranial, Other o Enhancing mass, usually multiple o Primary tumor typically known • Subependymoma o Rare, benign, well-differentiated, intraventricular, ependymal tumor o Intraventricular, inferior 4th ventricle typical (60%) o T2 hyperintense lobular mass o Usually middle-aged or elderly male

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• Hemangioblastoma o Posterior fossa mass with cyst, enhancing mural nodule (60%); 40% solid mass o 80% cerebellar hemispheres; 15% vermis, 5% medulla, 4th ventricle o Often extend through FM • Intracranial Hypotension o Brain descent with tonsillar herniation &/or "sagging midbrain" in 40-50% o Diffuse, intense dural enhancement 85% o Headache caused by reduced intracranial CSF pressure • Chordoma, Clivus o Rare malignant tumor arising from remnants of primitive notochord o Destructive, T2 hyperintense midline mass in clivus o May extend into FM • Chondrosarcoma, Skull Base o Chondroid malignancy of the skull base, typically centered on petro-occipital fissure o Chondroid matrix on CT 50%; > 50% bone destruction o T2 hyperintense mass, heterogeneous enhancement o May extend into FM from adjacent bone • Giant Invasive Pituitary Macroadenoma o Pituitary macroadenoma with inferior extension to basisphenoid & basiocciput o Central skull base enhancing mass o No normal pituitary gland seen

CSF-like, lobular, extra-axial mass insinuates into cisterns, encases nerves/vessels o CPA 40-50%, 4th ventricle 15-20% • Dermoid Cyst o Midline mass with fat, may rupture o May involve posterior fossa, vermis, 4th ventricle • Syringomyelia o Cystic spinal cord cavity not contiguous with central cord canal o Expanded spinal cord with dilated, beaded, or sacculated cystic cavity • Neurenteric Cyst o Round/lobulated nonenhancing, slightly hyperintense mass in front of medulla, near pontomedullary junction o

Alternative Differential Approaches • Intra-axial mass: Diffuse astrocytoma, hemangioblastoma, metastases • Extra-axial mass: Meningioma, schwannoma, epidermoid, dermoid, neurenteric cyst, dolichoectasia • Skull base mass: Chordoma, chondrosarcoma, invasive pituitary macroadenoma • Ventricular mass: Ependymoma, metastases, subependymoma, hemangioblastoma • Tonsillar herniation: Chiari 1 & 2, intracranial hypotension

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Acquired

Tonsillar Herniation

Dolichoectasia

(Vertebrobasilar)

I Axial T2WI MR shows tonsillar herniation with the tonsils completely impacted into the foramen magnum obliterating the cisterna magna. This is commonly

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Axial T1WI MR shows ectasia of the vertebral arteries.

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(Left) Sagittal T1 WI MR shows herniaUon with diminished posterior fossa CSF The bony posterior fossa is small leading to a "mismatch" with the normal-sized cerebellum. The pointed cerebellar tonsils ~ protrude through the foramen magnum. (RighI) Sagittal T2WI MR shows dysgenesis of the corpus callosum ~ small posterior fossa, "beaked" tectum & downward shift of the pons, 4th ventricle, & cerebellum. Note also cortical dysplasia.

"tl

c::

III

(Left) Sagittal TI WI MR shows marked enlargement of the medulla ~ with extension through the foramen

magnum,

related

to

a brainstem glioma. Note encasement of the basilar artery. (Right) Sagittal T1 C+ MR show5 a clival meningioma with marked enhancement & a dural tail that extends through the foramen

magnum

11):],

Schwan noma (Left) Axial T1 C+ MR shows a large, enhancing extra-axial mass extending through the foramen magnum with a small lobule projecting anteriorly into the jugular foramen shown to be glossopharyngeal schwannoma. When farge, 5chwannomas may extend through the foramen magnum. (Righi) Sagittal T1 C+ MR shows a 4th ventricular heterogeneously enhancing mass extending posleroinferiorly into the cisterna magna & foramen magnum!:].

=-

I 4 44

MASS

FORAMEN MAGNUM

MASS Ql ;j

Co

...

OJ

Hemangioblastoma

Ql

(LeFt) Sagittal T2WI MR shows a large; heterogeneous 4 th ventricular subependymoma with extension through the foramen magnum. Heterogeneity is usually seen in larger lesions, related to cystic changes, blood products, &Ior calciFication. (Right) Sagillal n C+ MR shows an enhancing vermis mass extending through the Foramen magnum Ell with associated hydrocephalus. These primary tumors are

=

::I

m

~ Q], OJ X OJ (f)

'0 OJ () (1) (/)

OJ

:::J

C. (f) C IJ'

OJ OJ

~ ()

most common in the

::J'

cerebellar hemispheres.

Q. c.

;j

o (/)

m ~ Dermoid

;j (/)

Cyst (LeFt) Coronal T2WI MR shows a lobulated

hyperintense mass extending through the Foramen magnum Bright OWl conFirms the diagnosis of epidermoid. (Right) Sagiual nWI MR shows a

=.

hyperintense

extra-axial mass

at the foramen magnum Fat-saturation technique confirms

=.

fat in this dermoid

cyst.

Syringomyelia

Neurenteric

Cyst (LeFt) Sagillal T2WI MR shows syringomyelia extending into the brainstem (syringobulbia). There is T2 hyperintense signal with expansion

of the spinal cord

extending From the medulla to the cervical spinal cord. (Right) Sagittal nWI MR shows a large, well-delineated extra-axial foramen

magnum

mass

=

elevating & displacing the pons & medulla. The mass is very slightly hyperintense compared to CSF. Typical location

for neurenteric

cyst.

I 4 45

ENHANCING

(/l

c ~

CRANIAL NERVE(S)

OJ

u;

(5 "0

'0 C L U

~

ro .0 :J (j)

"0

c ro

(/l

OJ

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ro

0. (j)

ro

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ro, ro ~

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c: III

DIFFERENTIAL DIAGNOSIS

o

Common • Metastases • Neurofibromatosis Type 2 • Neurofibromatosis Type 1 o Plexiform eurofibroma o Optic Nerve Glioma • Multiple Sclerosis o Optic Neuritis Less Common • Viral, Post-Viral Neuritis o Bell Palsy o Herpes Zoster o ADEM • Lyme Disease • Lymphoma • Neurosarcoid • Opportunistic Infection, AIDS • Leukemia Rare but Important • Ischemia o Diabetes o Arteriolosclerosis (Microvascular Disease) • Langerhans Cell Histiocytosis • Chronic Inflammatory Demyelinating Polyneuropathy (ClOP)

ESSENTIAL INFORMATION

I 4 46

o

Key Differential Diagnosis Issues • Enhancement of cisternal, cavernous sinus CN segments always abnormal • Which cranial nerve(s) affected? o Optic nerve: MS, NFl (optic glioma), viral/post-viral o C 3, 6: Often ischemia (diabetes, arteriolosclerosis) o CN?: Bell palsy, Herpes zoster (Ramsay Hunt) o CN8: Schwannoma (sporadic or NF2 associated), metastasis • If multiple nerves involved, consider o Metastases, lymphoma, leukemia o NF2 o Lyme disease o ClOP (especially if nerves massively enlarged) • History important o Optic neuritis (majority have or develop MS)

Known neoplasm Flu-like illness (ADEM, viral neuritis)

Helpful Clues for Common Diagnoses • Metastases o Most common: CSF spread • Involves pia, CNs, may extend along perivascular spaces • Multiple thickened nerves> solitary involvement • Fundus of CPA/lAC most common site o Less common: Perineural tumor extension from extracranial primary • Extension into cisternal CN uncommon • Squamous cell, adenoid cystic carcinoma (CNS, ? involvement most common) • Neurofibromatosis Type 2 o Multiple schwannomas o Bilateral acoustic schwannomas diagnostic o Acoustic schwannoma plus schwannoma of one other CN highly suggestive o Schwannoma of "small" CN (e.g., C 3, 4) should raise consideration of F2 • Neurofibromatosis Type 1 o Plexiform Neurofibroma • Intracranial involvement less common than scalp, orbit, face (e.g., parotid gland) • Plexiform neurofibromas of CN3 or CNS may extend intracranially, involve cavernous sinus o Optic Nerve Glioma • Most are typical pilocytic astrocytomas (PAs)

• 15-20% of NFl patients develop PA (most commonly in optic pathway) • Up to 1/3 of patients with optic pathway PA have Nfl • Enhancement varies from none to striking • May be uni- or bilateral, extend to/from orbit, involve nerves/ chiasm/h ypotha lam us • Multiple Sclerosis o Optic nerve (ON) most commonly affected o 50-60% of patients with optic neuritis ultimately develop MS o Imaging • Mildly enlarged, enhancing ON • 40% extend to intracanalicular, prechiasmatic/chiasmatic segments

en

ENHANCING CRANIAL NERVE(S)

" c:

o

• Other CNs (e.g., trigeminal nerve) less commonly affected Non-MS associated optic neuropathy • Infectious (viral) • Anterior ischemic optic neuropathy (AION)

Most common intracranial involvement optic nerve/chiasm/hypothalamus o Other CNs rare • Opportunistic Infection, AIDS o Tuberculous meningitis, CMV neuritis (retina, optic nerve) o

=

III

::::l

Co

lD ....• III

::::l

m ~ ....• , Q) Q)

Helpful Clues for Less Common Diagnoses • Viral, Post-Viral Neuritis o Bell Palsy • Enhancement of intratemporal facial nerve • "Tuft" of enhancement in lAC less common o Herpes Zoster • Ramsay Hunt syndrome (Herpes zoster oticus) = vesicular rash of pinna, involvement of CN?, 8 in lAC, cochlea • Other CNs (e.g., 5) less common o ADEM • Rare manifestation of post-viral demyelination • Affected nerve minimally enlarged, enhances transiently • Lyme Disease o Most common = MS-like lesions in patient with skin rash, flu-like illness following deer tick bite o Can involve multiple CNs (CN? most common) • Lymphoma, Leukemia o Diffuse pial tumor spread - multiple CNs • Neurosarcoid

Helpful Clues for Rare Diagnoses • Ischeluia o Diabetes, microvascular disease • CN3, 6 most commonly affected • Optic nerve (anterior ischemic optic neuropathy) less common o Transient enhancement, then atrophy • Langerhans Cell Histiocytosis o Usually children o Optic nerve/ ch iasm/h ypo thala m us/ infundibular stalk most common • Infiltrated, thickened structures enhance strongly, uniformly o Disseminated intracranial LCH rare • Sulcal/cisternal enhancement • Multiple enhancing C s • Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) o Typical setting = chronic MS o Serial demyelination, remyelination "onion bulb" thickening of affected nerves o Massive enlargement, enhancement of spinal, cranial nerves (spinal> > C s)

x

0;" (f)

"0 Q) ()

Ul Q)

::::l Co (f) C

cr Q)

iil () :J"

:::l

o

a: o Ul

CD ....• :::l

Ul

Metastases

Axial TI C+ MR in a patient with disseminated malignant glial neoplasm shows diffuse enhancing metastases covering brain, CPA/lACs both

abducens nerves ~.

=.

Axial TI C+ F5 MR shows thickened, enhancing V2 in a patient with adenoid cystic carcinoma with perineural tumor spread in pterygopalatine fossa extending along foramen rotundum into Meckel cave ~

=.

I 4 47

ENHANCING

(/)

c ~

CRANIAL

NERVE(S)

Q)

U5 u

:g o

c

-<: <..l

l1l l1l

~

..c

:::l (fJ "0 C

l1l (/)

Q)

<..l

l1l 0-

(fJ

l1l

'x l1l , l1l ~ X w

Neurofibromatosis Type 2

Neurofibromatosis Type 2

Plexiform Neurofibroma

Optic Nerve Glioma

Multiple Sclerosis

Multiple Sclerosis

(Left) Axial T1 C+ MR shows bilateral acoustic schwannomas with classic "ice cream appearance

on cone"

m.

Note

arachnoid cyst associated with left lesion 82. (Right) Coronal T1 C+ FS MR in a patient with known NF2 shows trigeminal schwannomas in both Meckel caves as well as multiple schwannomas involving cervical spinal

=

nerve roots ~.

C III

~

aJ

"tl

c

III

:::l

oX:

en (Left) Axial T1 C+ FS MR in a patient with NF 1 shows unusually extensive plexiform neurofibroma of CN3 branches, extending from orbit through markedly enlarged

orbital fissure into

expanded cavernous sinus

=. Note scalp plexiform

neurofibroma 82. (Courtesy M. Martin, MOJ. (Right) Axial CECT in a child with NFl shows bilateral optic nerve gliomas extending through optic canals £0 chiasm The right optic nerve is noticeably enlarged, enhancing ED.

=.

(Left) Axial T1 C+ FS MR shows enhancement of almost the entire length of the left optic nerve =:I, including

segment

within

optic canal 82. (Right) Coronal T1 C+ FS MR in a patient with MS, left trigeminal neuralgia, shows enhancing left CNS Compare to normal nonenhancing right side ED.

=.

I 4 48

ENHANCING

CRANIAL

NERVE(S)

00

~ c::

III

:::l

C-

..,

O:!

Lyme Disease

~,

rs

(Lefl) Axial T7 C+ MR with magnified view shows variant case with enhancing "(undaltuft" in lAC with enhancing labyrinthine segment 81 leading to geniculate ganglion § (RighI) Axial T7 C+ FS MR shows enhancement in left lAC involving both CN7 and CN8 Note pial enhancement along pons 81 extending along CN6 from its brainstem exit to Dorelia canal PJ:].

=-

=.

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~ OJ, OJ

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rr OJ

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o w· eD .., :J

Neurosarcoid

(J)

(Lefl) Axial T7 C+ FS MR in a patient with known systemic lymphoma, right 3rd nerve palsy shows thickened, enhancing right oculomotor nerve

=-

intraconaf

retrobulbar enhancing tumor 81. (RighI) Axial T7 C+ MR shows enhancemen/ of both thickened optic nerves extending from optic cana/to optic chiasm

=.

Opportunistic Infection, AIDS

Chronic Inflammatory Demyelinating Polyneuropathy (ClOP) (Lefl) Axial T7 C+ MR in a patient with HIV/AIOS who presented

with confusion,

seizures, shows tubercular

meningitis r.:= that thickens, encases the righllrigeminal nerve [;B (RighI) Coronal T I C+ FS MR in a 39 year old woman with longstanding MS, left facial pain shows both trigeminal nerves are thickened, enhancing ffi

I 4 49

en c ~

CSF-liKE EXTRA-AXIAL FLUID COLLECTION

Q)

Ul U "0

'0 C £ U

~

<1l <1l .0

::::J (fJ "0 C

<1l

en Q)

u <1l n. (fJ <1l

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III

DIFFERENTIAL DIAGNOSIS Common • Aging Brain, Normal • Enlarged Subarachnoid Spaces • Mega Cisterna Magna • Subdural Hematoma, Chronic • Subdural Hygroma Less Common • Subdural Effusion • Dandy-Walker Continuum • Arachnoid Cyst • Intracranial Hypotension

• Mega Cisterna Magna o Cisterna magna measuring> 10 mm o Vermis intact • Subdural Hematoma, Chronic o Hypodense subdural collection; may be hyperdense to CSF & have septations • Subdural Hygroma o Results from tear in arachnoid; CSF density

Key Differential Diagnosis Issues • Absence of mass effect & veins traversing subarachnoid space suggests normal variant

Helpful Clues for Less Common Diagnoses • Subdural Effusion o Sterile CSF-like collection associated with meningitis • Dandy-Walker Continuum o Large posterior fossa with big CSF cyst o 4th ventricle appears contiguous with cyst • Arachnoid Cyst o CSF density/intensity ± bone remodeling • Intracranial Hypotension o Characteristic postural headache related to reduced intracranial CSF pressure o Subdural collections in 15% o "Slumping midbrain", low tonsils, dural enhancement

Helpful Clues for Common Diagnoses • Aging Brain, Normal o Decreased brain volume; mild low density/high intensity periventricular rim o No mass effect • Enlarged Subarachnoid Spaces o Physiologic enlargement of subarachnoid spaces o Benign macrocephaly of infancy o Head circumference> 95%

Helpful Clues for Rare Diagnoses • Extra-Axial Empyema o Peripherally enhancing extra-axial collection; DWI bright! • Cephalocele/Meningocele o Congenital herniation of intracranial structures through a skull defect • Epidermoid Cyst (Mimic) o CSF-like extra-axial mass; basal cisterns common

Rare but Important • Extra-Axial Empyema • Cephalocele/Meningocele • Epidermoid Cyst (Mimic)

ESSENTIAL INFORMATION

Aging Brain, Normal

Enlarged Subarachnoid

Spaces

I 4 50

Axial T2WI M R shows prominence of subarachnoid spaces (SAS) due to age-related cerebral involution. Lilck of mass effect & veins traversing SAS IdI is characteristic.

Axial T2WI MR shows prominent CSF spaces in this infant with macrocrania. Small linear flow voids g.. represent veins traversing the SAS. Enlarged SASresolve withoUltherapy by 12-24 month,.

en

CSF-liKE EXTRA-AXIAL FLUID COLLECTION

" c:

Ql

;, Co

.., OJ

Subdural Hematoma, Chronic

Ql

(Left) Sagiltal T1 WI MR shows a prominent retrocerebellar CSF space 81 without compression. There is a normal 4th ventricle & vermis ~. Mega cisterna magna is a normal variant & requires no treatment. (Right) Axial NrCT shows

m

~ .., ,

OJ OJ

>< 0;' (f)

" OJ

(1 (l)

subdural

en OJ ;,

The anterior

C.

acule-an-chronic frontoparietal hematoma.

;,

right

portion shows the hypodense chronic component I!:i'l with associated mass effect. The more acute blood layers posteriorly,

(f) C

0-

m ~

OJ

(1

::T :J

o

1i

o iii'

CD Dandy-Walker Continuum

3 en

Arachnoid Cyst (Left) Sagittal T2WI MR shows a large posterior fossa cyst continuous with the 4th ventricle. Note also the superiorly rotated vermian remnanlldl. classic for Dandy-Walker malformation. Patient a/so has macrocrania & hydrocephalus. (RighI) Axial T1 WI MR shows CSF

intensity extra-axial lesion

=-

causing thinning of the adjacent calvarium arachnoid cyst. Arachnoid cysts follow CSF signal on all MR sequences.

Intracranial Hypotension (Left) Coronal T1 C+ FS MR shows small bilateral subdural

effusions

=

over

the cerebral convexity. Note the diffuse dural thickening & enhancement characteristic for intracranial hypotension, (Right) Axial T1 C+ MR shows a peripherally enhancing subdural empyema in this sinusitis patient. OWl MR (not shown) shows restricted diffusion which can help differentiate empyema from more benign extra-axial fluid collections.

a

=

I 4 51

CSF-L1KE EXTRA-AXIAL

VJ C

MASS

L-

Q)

~

() "0

DIFFERENTIAL DIAGNOSIS

·0 C £ U Cll L-

Cll

.n ::::J CfJ

"0 C Cll VJ Q) U Cll Q.

CfJ Cll

·x 'P Cll L-

X

W

c:

Common • Arachnoid Cyst • Neurocysticercosis less Common • Pineal Cyst • Schwannoma (Cystic) • Epidermoid Cyst Rare but Important • Neurenteric Cyst • Leptomeningeal Cyst • Callosal Dysgenesis • Holoprosencephaly (Dorsal Cyst)

III L-

a! 'tl

c:

III

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Enhancement is helpful to differentiate CSF-like extra-axial masses Helpful Clues for Common Diagnoses • Arachnoid Cyst o Nonenhancing CSF-like mass, bone remodeling • Neurocysticercosis o Cyst with a scolex is pathognomonic o Racemose (grape-like) in basal cisterns: No scolex is typical o Subarachnoid & intraventricular disease often symptomatic from hydrocephalus &/or meningitis (enhancing)

Arachnoid

I 4 52

Helpful Clues for less Common Diagnoses • Pineal Cyst o Lies dorsal to midbrain at pineal gland o Usually asymptomatic, less than 2 cm • Schwannoma (Cystic) o Commonly located in cerebellopontine angle (CPA) cistern o Enhancement typical • Epidermoid Cyst o Lobular, insinuating nonenhancing mass o Restricted diffusion & FLAIR hyperintensity differentiates from arachnoid cyst Helpful Clues for Rare Diagnoses • Neurenteric Cyst o Posterior fossa: Anterior to brainstem, CPA o Nonenhancing midline or paramedian cyst o MR signal variable (protein content) • Leptomeningeal Cyst o Underlying brain shows encephalomalacia o Communicates with subarachnoid space o Well-marginated skull defect at site of cyst • Callosal Dysgenesis o Interhemispheric cyst common o Parallel lateral ventricles, colpocephaly, high riding 3rd ventricle • Holoprosencephaly (Dorsal Cyst) o Hydrocephalus is almost always present o Look for fused thalami, absence of interhemispheric fissures, septum pellucidum o May see corpus callosum agenesis

Arachnoid

Cyst

Sagittal T1WI MR shows an extra-axial mass causing thinning of the inner table of the skull Arachnoid cysts are benign & usually found incidentally. They follow CSFon all MR sequences.

'-=.

=

Cyst

Sagittal T1WI MR shows a large frontal arachnoid cyst with associated mass errect. Vast majority of

arachnoid cysts are incidentally found treatment.

&

require no

CSF-liKE

EXTRA-AXIAL

MASS III

::::l C.

...

OJ

Neurocysticercosis

III

Pineal Cyst (Left) Axial T1 C+ MR shows multiple hypointense cysts with mild peripheral enhancement. Note interhemispheric I:] & sylvian fissure E!lI cysts. Subarachnoid spaces are the most common location for NCC cysts. Cisternal NCC may be complicated by meningitis, hydrocephalus, or vasculitis. (RighI) Sagillal T1 WI MR shows a cystic mass in the pineal region. These are typically less than 2 em & incidental. Enhancement of compressed pineal gland may be seen.

=

::::l

m ~ ... Ql

Q, ~. Ql

(fJ "t)

Ql (') (l)

en Ql

:J

C. (fJ C 0Ql

...

Ql

(')

::T ::::l

o

c: o (jj' CD ...

Neurenteric

:J en

Cyst (Left) Axial T2WI MR shows wel'·circumscribed extra-axial mass ~ which is isointense to CSF. FLAIR & OWl MR can differentiate this lesion from an arachnoid cyst. (Right) Sagittal T1 C+ MR shows a mildly hyperintense non enhancing lesion in the prepontine cistern typical location for neurenteric cyst. MR signal is dependent on protein content of cyst. They are typically T I hyperintense or isointense & T2 hyperintense (to CSf).

=-

Callosal Dysgenesis (Left) Axial T2WI MR shows corpus callosum dysgenesis with a large dorsal interhemispheric cyst"" & prominent azygous artery The large dorsal cyst & the parallel lateral ventricles E!lI are typical of callosal dysgenesis. (Right) Axial NECT shows a large dorsal cyst associated with alobar holoprosencephaly~. Note absence

of septum

pellucidum

artiFacts ~

1:]. Streak are due to shunt

(not shown) inserted into the cyst.

I 4 53

SULCAL/CISTERNAL

rJJ

E

ENHANCEMENT

Q)

]2 U -0

'0 C

.L:

U l\l l\l .0

~ :J

en -0

c

l\l

rJJ

Common • Meningitis • Meningeal Carcinomatosis • Lymphomatous Meningitis • Neurocysticercosis • Tuberculosis Meningitis

•

Q)

U l\l

n.

en l\l

'xl\l

, ~ X l\l

w

c

~ '"

llJ -0

c

=':J" -'en "

less Common • Neurosarcoid • Sturge-Weber Syndrome • Fungal Diseases • Aneurysmal Subarachnoid Hemorrhage (Subacute May Enhance) • Opportunistic Infection, AIDS • Leukemia Rare but Important • Neurocutaneous Melanosis • Meningioangiomatosis • Contrast Leakage

•

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • All meningitides (infectious, granulomatous, neoplastic) have similar imaging appearance (enhancing pia ± sulcal/cisternal enhancement) • Location, pattern only minimally helpful • Nodular "leptomeningeal" (pial) enhancement o Meningeal carcinoma tosis o Lymphomatous meningitis o Tuberculosis meningitis o Leukemia o eurosarcoid o Fungal diseases • Thick basal cistern enhancement o Tuberculosis meningitis o Fungal diseases o eurosarcoid o Pyogenic meningitis o Lymphoma o Neurosyphilis

I 4 54

Helpful Clues for Common • Meningitis o Clinical-laboratory (not • Positive CSF by lumbar o Imaging may be normal helpful)

Diagnoses imaging) diagnosis puncture early (FLAIR

Use imaging to detect complications (e.g., ventriculitis, hydrocephalus, subdural empyema, cerebritis/abscess, secondary ischemia, dural venous thrombosis) Meningeal Carcinomatosis o CNS neoplasms (e.g., GBM, medulloblastoma, pineal tumors, choroid plexus tumors), extra-CNS primary tumors (breast, lung, melanoma common) o Look for other lesions (parenchyma, bone) Lymphomatous Meningitis o Involvement of leptomeninges or dura, more commonly in secondary lymphoma • Primary CNS lymphoma: Typically periventricular parenchymal disease o Often affects both brain, spine Neurocysticercosis o Cysts often in deep sulci, may incite intense inflammatory reaction o Cisternal NCC may appear racemose (multilobulated, grape-like), typically lacks scolex • Complications: Meningitis, hydrocephalus, vasculitis o Cisterns> parenchyma> ventricles o Best diagnostic clue: Cyst with "dot" (scolex) inside Tuberculosis Meningitis o Most common presentation of active CNS o

DIFFERENTIAL DIAGNOSIS

•

TB

Predilection for basal cisterns Complications: Hydrocephalus, ischemia common o Look for extracerebral TB (pulmonary) o TB often mimics other diseases like neoplasm

o

o

Helpful Clues for less Common Diagnoses • Neurosarcoid o Dural, leptomeningeal> > parenchymal disease o Lacy leptomeningeal enhancement typical o Look for infundibular stalk involvement o CXR may be helpful to assess for hilar/paratracheallymphadenopathy (most have systemic disease) • Sturge-Weber Syndrome o Atrophy of affected hemisphere o Pial angioma enhances o Ipsilateral choroid plexus often enlarged o Abnormally prominent medullary (deep white matter), ependymal veins

en

SULCAL/CISTERNALENHANCEMENT

""C • Fungal Diseases o Coccidioidomycosis, cryptococcus often basilar • Aneurysmal Subarachnoid Hemorrhage (Subacute May Enhance) o 1'2* GRE: Hypointense hemosiderin deposition in 70-75% of patients with prior SAH • Opportunistic Infection, AIDS o Meningeal involvement in AIDS (HIV or opportunistic infection> tumor) • Acute aseptic HIV meningitis • Cryptococcal or TB meningitis • Lymphoma: Extension of parenchymal disease • Other fungal: Candidiasis, aspergillosis, coccidiosis • Consider neurosyphilis • Leukemia o Meningeal disease, usually with acute lymphoblastic leukemia (ALL) o Multiple lesions at multiple sites are suggestive of diagnosis Helpful Clues for Rare Diagnoses • Neurocutaneous Melanosis o Giant or multiple cutaneous melanocytic nevi (GCMN) and o Benign, malignant CNS melanotic lesions occur o Foci of 1'1 hyperintensity (parenchymal melanosis) in amygdala or cerebellum

Diffuse/focal pial enhancement; may extend into parenchyma via perivascular spaces o Pre-contrast 1'1WI sulci/cisterns may be normal, iso-, or hyperintense • Meningioangiomatosis o Neurofibromatosis found in Yz of patients (particularly NF2) o Rare, hamartomatous cortical/leptomeningeal malformation o Best diagnostic clue: Cortical mass with Ca++ (with or without cysts) • Contrast Leakage o Increased signal in CSF on 1'1WI and FLAIR o Dialysis-dependent patient with end-stage renal disease o Contrast overload o Leakage from tumor o

Cll

~ Co

...

OJ Cll

~ m ~ ... 0>

dJ

>< 00·

en

-0 0>

()

<0

rn 0>

::J Co

en c C-

...

O>

0>

()

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o

Ci

Q rn

ro... ::J

Other Essential Information • Thin, curvilinear enhancement over brain surface reflects pial disease • Predilection for basal cisterns in inflammatory, granulomatous meningitis

'"

SELECTED REFERENCES 1. 2.

Fukui MB et al: MR imaging of thc mcningcs. Part II. Neoplastic disease. Radiology. 20] (3):60S-12, 1996 Meltzer CC et al: MR imaging of the meninges. Part I.

orrnal anatomic

features and nonneoplastic

Radiology. 201(2):297-308,

Meningeal

disease.

] 996

Carcinomatosis

I Axial T1 C+ MR shows extensive leptomeningeal enhancement of the sulci

Axial T1 C+ MR reveals extensive leplOmeningeal carcinomatosis with a basal predominance. There is diffuse coaUng of the cerebellar folia with additional nodular areas of enhancement E2.

4 55

SULCAL/CISTERNAL

(/)

c ~ Ql

~

o "0

'6 c J::

()

ro ~ ro --"::J

(/)

(Left) Sagittal T1 C+ MR shows extensive leptomeningeal carcinomatosis with diffuse coating of the cerebellar folia ffi Scattered nodular areas

Ql

of enhancement

(f) "0 C

ro

()

ro

n. (f)

ro

'x ro, ro ~ X w c

~ '"

are evident

=.

in the supratenlorium (RighI) Axial T I C+ FS MR shows enhancement in the internal auditory canal and in Meckel cave on the

=

right !G. Note extensive fetro-orbital

enhancement

in

this patient with lymphoma

ffi

III "0

c

'::J" en "" (Left) Axial T1 C+ FS MR shows ring·enhancing right CPA cistern cysts 1:;;1 and thickened enhancing meninges 81, (RighI) Axial T1 C+ FS MR shows small areas of ring-enhancement

in

the subarachnoid space 1:;;1.

(Left) Axial T1 C+ MR shows intense basal meningeal enhancement ffi (RighI) Axial T 1 C+ MR shows linear and nodular coating of the midbrain 1:;;1, Note thickening of the infundibular stalk PJ:J:l,

I 4 56

ENHANCEMENT

SULCAl/CISTERNAL

ENHANCEMENT III

::l

a. Sturge-Weber

Syndrome

Fungal

CD .,

Diseases

III

(Left) Axiat T7 C+ MR shows serpentine leptomeningeal enhancement ffi feft cerebrat atrophy, thickening o( the catvariat diptoic space =:1 and hypertrophy of the ipsilateral choroid plexus •. (Right) Axiat T7 C+ MR shows thick enhancement of the basal cisterns in this patient with coccidioidomycosis meningitis.

=

::l

m ~ ., III o III X

Qj.

en

-0

III

o <1l

VI III

::l

a.

en c rr

.,

III III

o

:T ::l

o

0.:

o (ii. CD ., Fungal

Diseases

Neurocutaneous

::l

Melanosis

VI

(Left) Axiat T7 C+ MR shows thick enhancement in the subarachnoid space and atong the pia =:1 Coccidioidomycosis meningitis. (Right) Axiat TI C+ MR shows intense enhancement

of the en/ire

surface of the brain and adjacent subarachnoid

space. Note associated communicating

hydrocephatus.

Meningioangiomatosis

Contrast leakage (Left) Sagittat T7 C+ MR shows serpentine cortical enhancement 1m. Consider meningioangiomalosis when a calciried corUea/lesion \.vill1 or without cysts is delected. (Right) Axiat FLAtR MR in patient with renal failure, contrast-enhanced MRA of the abdomen (\.'1'0 days earlier shows contrast accumulation in the CSF EE which appears diffusety hyperintense.

I 4 57

rJ) C

FAT IN SULCI/CISTERNS/VENTRICLES

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DIFFERENTIAL DIAGNOSIS Common • Lipoma • Subacute Hemorrhage (Mimic) Less Common • Dermoid Cyst (Ruptured) • Teratoma Rare but Important • Lipoidal Contrast (Mimic) • Metaplastic Meningioma (Lipomatous) • Choroid Plexus Xanthogranuloma (Mimic) • Encephalocraniocutaneous Lipomatosis

c: III L

a:l "'C

c:

III

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Review brain CT; fat may have confusing MR signal intensity • MR fat suppression technique helps differentiate lesions Helpful Clues for Common Diagnoses • Lipoma o Well-defined nonenhancing fatty mass o Locations: lnterhemispheric/pericallosal, suprasellar, quadrigeminal, & cerebellopontine angle (CPA) o Bulky interhemispheric/pericallosal lipomas often associated with agenesis/dysgenesis of corpus callosum • Subacute Hemorrhage (Mimic) o Tl shortening in subacute blood may mimic fat

I 4 58

=

Sagittal TlWI MR shows a lipoma with corpus callosum hypoplasia. Majority are supratentorial (80%), most common along interhemispheric fissure. Suprasellar & pineal region are less common.

o o

Blood products show "blooming" artifact on GRE sequence Does not suppress with fat suppression

Helpful Clues for Less Common Diagnoses • Dermoid Cyst (Ruptured) o Fat droplets in sulci o Signal nulled with fat suppression • Teratoma o Midline mass containing Ca++, soft tissue, cysts, & fat • Soft tissue component enhances o Pineal region common; suprasellar less common Helpful Clues for Rare Diagnoses • Lipoidal Contrast (Mimic) o Oil-based contrast agent o High Tl signal intensity • Metaplastic Meningioma (Lipomatous) o Dural-based enhancing mass with fat density/signal intensity o Look for adjacent hyperostosis • Choroid Plexus Xanthogranuloma (Mimic) o Nonneoplastic, noninflammatory cysts of choroid plexus o Low density on CT may mimic fat • Encephalocraniocutaneous Lipomatosis o Scalp lipomas ipsilateral to brain anomalies o CPA, Meckel cave, & foramen magnum lipomas

Sagittal TI WI MR shows an asymptomatic ribbon-like pericallosaJ lifX>ma ~. Lipomas are congenital malformations, not true neoplasms. 20% are infra tentorial,

most commonly

in the CPA.

FAT IN SULCI/C1STERNS/VENTRICLES

00

"

c:

(Left) Axial T I WI MR shows a ruptured dermoid 81 with characteristic fat droplets throughout the subarachnoid space 111.1. Ventricular fat-fluid levels are common. Chemical meningitis is a

common complicalion.

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~ ~ Ol Q, X

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(Right) Axial NECT shows a suprasellar mass I'll] containing fat & calcifications, teratoma. These midline masses are

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most commonly in the pineal region as are other germ cell

CT Ol Ol

tumors. The sort tissue components of these lesions

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enhance.

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Teratoma

en (Left) Axial T1 WI MR shows a heterogeneous lesion in the pineal region with small hyperintense foci related to fat. The lateral & 3rd ventricles are enlarged due to compression of the cerebral aqueduct. (Right) Sagittal T1 WI MR shows a metaplastic (lipomatous) meningioma with characteristic T1 hyperinlensily related to fat Ea. Signal characteristics are from triglyceride fat droplets

=

within metaplastic adipocyles.

Choroid Plexus Xanthogranuloma (Mimic) (Left) Axial CECT shows choroid plexus cysts in the atria of the lateral ventricles. These are commonly seen as incidental findings. On CT, the cysts may mimic fat. (Right) Sagittal T1WI MR shows encephalocraniocutaneous lipomatosis, a rare congenital neurocutaneous syndrome, which may be characterized by extensive intracranial lipomas. A large lipoma extends into the upper cervical canal P1t] & another in the CPA 81.

I 4 59

EXTRA-AXIAL

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DIFFERENTIAL DIAGNOSIS

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Common • Normal (Normal Arteries, Veins) • CSF Pulsation • Saccular Aneurysm • Fusiform Aneurysm, ASVD • Arteriovenous Malformation • Developmental Venous Anomaly Less Common • Dural A-V Fistula • Thrombosis, Dural Sinus • Fusiform Aneurysm, Non-ASVD • Dissecting Aneurysm • Pseudoaneurysm Rare but Important • Vein of Galen Malformation • Venous Varix

-"(f)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Vascular vs. CSF flow void (FV) o Vascular FVs sharply demarcated from surrounding CSF o If large, vascular FVs may cause phase artifact • Vascular FV vs. acutely thrombosed artery/vein o Thrombus iso- on Tl, hypointense on T2WI, can mimic FV o Do T2* (GRE/SWI) - clot "blooms"

Normal

I 4 60

(Normal

Arteries,

a.

Helpful Clues for Less Common Diagnoses • Dural A-V Fistula o Older; usually prior dural sinus thrombosis o Direct AV shunt • Thrombosis, Dural Sinus o Prominent collateral veins • Fusiform Aneurysm, Non-ASVD o Often more distally located than ASVD o Vasculopathy, vasculitis, mycotic, oncotic • Dissecting Aneurysm o Extra- > intracranial; VA > supra clinoid ICA Helpful Clues for Rare Diagnoses • Vein of Galen Malformation o t VOG, feeding/draining vessels • Venous Varix o Seen with AV shunting, venous strictures

Normal

Veins)

Axial T2WI MR shows paired ACA flow voids "on end" curvilinear MCA flow voids internal cerebral veins 1'71 proximal straight sinus ~ & superior sagittal sinus !:ll.

.2b

Helpful Clues for Common Diagnoses • CSF Pulsation o Ill-defined signal loss near artery • Saccular Aneurysm o Typically involve major branch points • Fusiform Aneurysm, ASVD o Long segment & focal outpouching (BA > ICA/branches) • Arteriovenous Malformation o Extra-axial feeding, draining vessels o Look for aneurysms (feeding arteries, intranidal), venous varices • Developmental Venous Anomaly o Draining vein & enlarged medullary veins o Tl C+ best sequence

=-

(Normal

Arteries, Veins)

Axial T2WI MR shows superior sagittal sinus flow void cortical veins entering sinus ~ .•. & superficial

cortical veins over the convexities ~.

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Ul

EXTRA-AXIAL FLOW VOIDS

c: III

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Co III .,

CSF Pulsation

III

Saccular Aneurysm (Left) Axial T2WI MR shows localized signal loss in the prepontine cistern CSF ~ due to pulsations from the basilar artery =:II. (Right) Axial T2WI MR shows a rounded flow void in the fissure It] representing

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(Left) Axial T2WI MR shows an ovoid mass that involves the horizontal segment of the left middle cerebral artery =:II. Note tortuous, elongated "flow voids" in both middle cerebral arteries. (Right) Axial PO FSEMR shows enlargement

of the internal

cerebral veins ~ prominent

as well as

areas of flow void

in an AVM nidus located in the lateral basal ganglia 8:1.

Developmental

Venous Anomaly

Dural A-V Fistula (Left) Axial T2WI MR shows

a

solitary prominent

flow

void near the vertex ~ that is substantially larger than other vascular flow voids at this level =:II. (Right) Axial T2WI MR shows high signal in the left transverse sinus & a number punctate &

or

curvilinear

signal voids

within it These small flow voids are part of a dural AVF within a chronically thrombosed dural sinus. Compare with the normal flow void of right transverse

sinus=.

I 4 61

11 HYPERINTENSE

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DIFFERENTIAL DIAGNOSIS Common • MR Artifacts, Flow-Related • MR Artifacts, Magnetic Susceptibility • Subarachnoid Hemorrhage • Intraventricular Hemorrhage • Meningitis

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ESSENTIAL INFORMATION Key Differential Diagnosis Issues • MR artifact common at high field strengths • CSF hemorrhage & infection often causes "dirty CSF", hyperintense to CSF & isointense to brain parenchyma o CSF FLAIRhyperintensity more common than true T1 CSF hyper intensity Helpful Clues for Common Diagnoses • MR Artifacts, Flow-Related o Pulsation artifact in phase encoding direction o Confirm artifact when seen outside skull • MR Artifacts, Magnetic Susceptibility o "Black holes" with T1 bright rim o Changing phase encode direction confirms

MR Artifacts,

• Subarachnoid Hemorrhage o May be traumatic, aneurysmal, or nonaneurysmal perimesencephalic • Location helps determine etiology o Typically isointense to brain, "dirty CSF" • Intraventricular Hemorrhage o Typically hyperintense to CSF & isointense to brain with a fluid level o May be T1 hyperintense, related to age • Meningitis o Typically isointense to brain, "dirty CSF" o Meningeal enhancement classic Helpful Clues for Less Common Diagnoses • Ventriculitis o Debris in ventricles from sediment, cells o Typically hyperintense to CSF & isointense to brain with a fluid level Helpful Clues for Rare Diagnoses • Dermoid Cyst (Ruptured) o Fat droplets within CSF spaces o Suppress with fat-saturation • Carcinomatous Meningitis o Rare, related to blood, cells, melanoma • Contrast Complications, NOS o Chronic renal failure causes delayed excretion & hyperintensity from recirculation o Gadolinium leak from lack of intact blood-brain barrier: Infection, PRES • Retained Pantopaque o Often focal T1 hyperintensity in CSF o Older adults (not used since 1980s)

Flow-Related

I 4 62

=

=

Axial TlWI MR shows CSFpulsation artifact on this spin echo Tl sequence (3T magneO. Anifact is confirmed by periodic high SII and low !l:?Jl signal

Axial T I C+ MR shows localized magnetic susceptibility artifact from an aneurysm clip. This results in localized Tl hyperintensity within the suprasellar cistern

artifacts in phase encoding

SII.

direction.

T1 HYPERINTENSE

CSF Ql

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Hemorrhage (Left) Axial TI WI MR shows "dirty" CSF in the suprasellar cistern, isointense with brain, related to aneurysm rupture. Note hydrocephalus with blood-fluid level ~ in lateral ventricle. (Right) Axial TI WI MR shows heterogeneous hyperintense signal anterior to the medulla. This is a typical distribution for nonaneurysmal perimesencephalic subarachnoid hemorrhage, which tends to collect around the midbrain & anterior to the pons.

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(Left) Axial TI WI MR shows hyperintense hemorrhage layering in the occipital horns 11II] & 3rd ventricle. Focal clot is seen in the frontal horn ~ in this patient with posterior fossa AVM rupture. (Right) Axial TlWI MR shows "dirty" CSF, isointens€

to brain

parenchyma in the basal cisterns ~ in this fungal meningitis patient. The CSF is also FLAIR hyperintense & enhances. Meningitis is a clinical-laboratory diagnosis.

Ventriculitis (Left) Axial TI WI MR shows debris layering posteriorly within the occipital horns in this 2 year old with

=

ventriculitis.

Note signal is

mildly hyperintense to CSF & isointense to brain. (Right) Sagittal TI WI MR shows numerous hyperintense foci in the subarachnoid spaces & supraselJar cistern SI related to rat droplets

=

from dermoid

rupture.

Hydrocephalus is caused by associated chemical meningitis.

I 4 63

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FLAIR HYPERINTENSE CSF

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Common • Subarachnoid Hemorrhage, OS • Intraventricular Hemorrhage • Meningitis • MR Artifacts, Magnetic Susceptibility • MR Artifacts, Flow-Related • MR Artifacts, Patient-Related • Metastases, Meningeal • Ventriculitis

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Less Common • Gadolinium in CSF due to o Blood-Brain Barrier Leakage o Chronic Renal Failure • Cerebral Ischemia-Infarction, Acute

•

Rare but Important • Dermoid Cyst (Ruptured) • Moyamoya •

ESSENTIAL INFORMATION

•

•

I 4 64

May be complicated by hydrocephalus, ventriculitis, abscess, vasculitis o Remains a clinical-laboratory diagnosis MR Artifacts, Magnetic Susceptibility o Regionally adjacent metal, blood, air-bone interfaces causes FLAIRhyperintensity o Distorts local magnetic field, altering null point for fluid (Tl), resulting in inappropriate high signal o Often seen close to aerated frontal sinuses & temporal bones o Common surrounding aneurysm clips MR Artifacts, Flow-Related o CSF flow artifacts are common in basal cisterns, foramen of Monro, aqueduct, & 4th ventricle o Periodic artifacts extending outside skull in phase encoding direction is diagnostic o Usually absent on spin echo sequences (Tl, T2); helpful to confirm artifact MR Artifacts, Patient-Related o Diffuse FLAIRhyperintensity o Common etiologies: Head motion, Propofol, 50% or greater supplemental oxygen (4-5x t signal with 100% 0,) Metastases, Meningeal o Usually due to cellularity &/or increased protein content within CSF o May be focal or diffuse o Meningeal enhancement typical o Adjacent bone changes common o Breast & lung most common distant primary tumors Ventriculitis o Ventriculomegaly with debris level o OWl bright & ventricular enhancement o Complication of meningitis, abscess, ventricular catheter o

DIFFERENTIAL DIAGNOSIS

Helpful Clues for Less Common Diagnoses • Blood-Brain Barrier Leakage o Etiologies include: Infection/inflammation, ischemia, tumor • Cerebritis, posterior reversible encephalopathy syndrome (PRES)may cause BBBleak • Acute/subacute stroke (poor prognostic sign suggests hemorrhagic transformation) • Neoplasms uncommon, usually with delayed imaging

FLAIR HYPERINTENSE CSF

(/I ;YC

r::

Gadolinium accumulates in CSF due to BBB leakage o May cause focal or diffuse FLAIR hyperintensity & enhancement • Chronic Renal Failure o Increased FLAIR related to delayed gadolinium clearance from circulation o May augment other pathologic causes of FLAIR hyperintensity o Usually seen with delayed imaging (may also be seen in normal patients) • Cerebral Ischemia-Infarction, Acute o May see hyperintense CSF related to vessel occlusion or slow flow o "Dot sign" related to occluded MCA branches in Sylvian fissure o Enhancement related to slow flow

o

o

Helpful Clues for Rare Diagnoses • Dermoid Cyst (Ruptured) o Fat-containing lesions are FLAIR bright from Tl shortening effects o Tl foci in subarachnoid spaces pathognomonic • Moyamoya o Progressive narrowing of distal ICA & proximal circle of Willis with collateraIs, anterior> posterior circulation o "Ivy sign": Bright FLAIR signal related to slow-flowing engorged pial vessels, thickened arachnoid membranes • More commonly seen in frontal & parietal lobes

Axial flAIR MR shows abnormal hyperinlensily wilhin lhe lefl-sided sulci The pauern of peripheral sulcal blood is more characteristic (or traumatic hemorrhage

=.

than aneurysm rupture.

Leptomeningeal "ivy sign")

enhancement

(contrast

Other Essential Information • Causes of pathologic FLAIR hyperintense CSF: Blood, elevated protein, or cells • FLAIR hyperintensity can be due to T2 prolongation or Tl shortening • "Fast" FLAIR can cause artifactual FLAIR hyperintensity Alternative Differential Approaches • FLAIR hyperintensity with enhancement: Meningitis, metastases, ventriculitis, blood-brain barrier leakage, chronic renal failure, acute ischemia, moyamoya

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REFERENCES

Morris JM et ai: Increased signal in the subarachnoid space on fluid-altenuated inversion recovery imaging associated with the clearance dynamics of gadolinium chelate: a potential diagnostic pitfall. AJNR Am J Neuroradiol. 28(10): 1964-7,2007 Stuckey SL et al: Hyperintensity in the subarachnoid space on FLAIR MRI. AJR Am J Roentgenol. ]89(4):913-21,2007 Cian[oni A et al: Artifact simulating subarachnoid and intraventricular hemorrhage on single-shol, fast spin-echo fluid-attenuated inversion recovery images caused by head movement: A trap for the unwary. AJNR Am J Neuroradiol. 27(4):843-9,2006 Frigon C et al: Supplemental oxygen causes increased signal intensity in subarachnoid cerebrospinal fluid on brain FLAIR MR images obtained in children during general anesthesia. Radiology. 233(1):S]-S, 2004 Bozzao A et al: Cerebrospinal fluid changes after intravenous injection of gadolinium chelate: assessment by FLAIR MR imaging. Eur Radiol. 13(3):592-7,2003

Axial flAIR MR shows high signal in lhe basal cislerns & along the sylvian fissure !:ll caused by subarachnoid blood relaled La aneurysm rupWre. Note also acule hydrocephalus 81.

=

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m ..,

~ en

I 4 65

FLAIR HYPERINTENSE CSF

Cfl

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(Left) Axial FLAIR MR shows

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en

the midbrain & in the suprasellar cistern 81. A

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Intraventricular Hemorrhage

=

small amount

of

intraventricular hemorrhage is presenl p:;J layering in the occipital horns. (Rigl1t) Axial fLAIR MR shows a basal ganglia hematoma in a patient with a hypertensive hemorrhage. Hyperintensity in the atrium of the left lateral ventricle B is indicaUve of intraventricular extension.

=

~

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MR Artifacts, Magnetic Susceptibility (Left) Axial FLAIR MR shows diffusely abnormal signal throughout the sulci 81 & pial surfaces caused by pyogenic meningitis. Hyperintensity in the choroid plexi p:;J suggests choroid plexitis. FLAIR hyperintense CSF may be more apparent than abnormal enhancement on contrast images in meningitis. (Right) Axial T2* GRE MR shows magnetic susceptibility artifact due to aneurysm clip placement in this patient with recent subarachnoid hemorrhage.

=

=

MR Artifacts, Flow-Related (Left) Axial FLAIR MR shows prominent round hyperinlense focus in the 4th ventricle Periodic artifacts in the phase encoding direction EJ confirm the suspicion of CSF pulsation artifact. (Rigl1t) Axial FLAIR MR shows hyperintensity within the CSf due to high levels of inspired oxygen at the time of imaging. This is a relatively

=.

=

common

artifact

requiring

sedation

study.

I 4 66

in patients for an MR

MR Artifacts, Patient-Related

flAIR

HYPERINTENSE

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CSF

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Ventriculitis (Left) Axial FLAIR MR shows scattered hyperintense signal at the sulci PJ:J:l & along the dura 1::1 related to meningeal metastatic disease. Enhanced images (not shown) revealed thickened, enhancing dura wilh subtfe sulcal enhancemenl. (Right) Axial FLAIR MR shows hyperintense material with the righllaleral venlricle ~ in this patient with meningoencephalitis & ventriculitis . Ventriculomegaly with debris level is most common imaging appearance.

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Barrier leakage

Blood-Brain

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Barrier leakage (Left) Coronal FLAIR MR shows focal hyperintense CSF 1::1 from local conlrast accumulation overlying a small parenchymal mass E!llI due 10 focal cerebritis. Contrast accumulation is relaled 10 blood-brain barrier leakage. (Rigl1t) Axial FLAIR MR shows diffuse CSf hyperinlensity due 10 gadolinium leakage in PRES. Note classic vasogenic edema in bOlh occipilal lobes ~ & extensive right temporal involvement. Renal

'"

=

function

Chronic

was normal.

Renal Failure (Left) Axial FLAIR MR shows diffuse hyperinlensity within the sulci in a patient with brain MR 2 days post-gadolinium injection for abdominal MRA (patient had a creatinine of 3.0). If history not known, would consider other meningeal processes. (Right) Axial FLAIR MR shows brighl CSF 1::1 in lhis patient with a hyperacute right MCA infarct. This abnormal signal is thoughllo be relaled 10 slow flow (luxury perfusion).

=

I 4 67

rn

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EXTRA-AXIAL

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DIFFERENTIAL DIAGNOSIS

•

Less Common • Epidural Hematoma • Subdural Hematoma, Mixed • Saccular Aneurysm • Lymphoma, Metastatic, Intracranial

•

Rare but Important • Neurosarcoid • Dural A-V Fistula • Leukemia • Hypertrophic Pachymeningitis • Extramedullary Hematopoiesis • Hemangiopericytoma • Retained Pantopaque

ESSENTIAL INFORMATION

I 4 68

•

Common • MR Artifacts, Flow-Related • MR Artifacts, Magnetic Susceptibility • Pneumocephalus • Physiologic Calcification, Dura • Meningioma • Metastases, Skull and Meningeal • Schwannoma

•

•

o Common surrounding aneurysm clips Pneumocephalus o Evidence of recent craniotomy or trauma o Completely black signal o Non-dependent location Physiological Calcification, Dura o Anterior parafalcine region most common o Ossification may demonstrate T1 hyperintensity centrally due to fatty marrow (mimics blood or lipoma) o Associations with chronic renal failure, where it may be more extensive Meningioma o Enhancing extra-axial mass with dural tail o Often T2 hypointense from high cellularity or intrinsic calcification Metastases, Skull and Meningeal o Enhancing extra-axial mass o Meningeal metastases typically associated with skull involvement o T2 hypointense if associated blood products (melanoma, renal cell carcinoma) o Primary tumor often known Schwannoma o Homogeneously enhancing extra-axial mass along cranial nerves, CPA most common o May show T2 hypointensity o T2 hyperintense cystic change is common

Helpful Clues for Less Common Diagnoses • Epidural Hematoma o Epidural collection in a trauma patient o Hyperacute, mixed & chronic hematomas may be T2 hypointense oGRE may show susceptibility artifact • Subdural Hematoma, Mixed o Subdural collection in a trauma patient o Hyperacute, mixed age & chronic hematomas may be T2 hypointense oGRE may show susceptibility artifact • Saccular Aneurysm o Round/ovoid T2 hypointense mass o Flow artifact in phase encoding direction o When thrombosed, challenging diagnosis • Maintain high suspicion when anatomically near vascular structures! • Lymphoma, Metastatic, Intracranial o Often a T2 hypointense dural lesion o Hypointensity related to high nuclear to cytoplasmic ratio o Systemic disease usually present

12 HYPOINTENSE o

Mimics other metastases

Helpful Clues for Rare Diagnoses

• Neurosarcoid o Hypointense durallesion(s) ± leptomeningeal disease> > parenchymal disease o Dural, leptomeningeal, subarachnoid space enhancement o 5% present as solitary dural-based extra-axial mass o Majority of patients have systemic disease • Dural A-V Fistula o Network of tiny vessels in wall of thrombosed dural venous sinus o Isointense thrombosed sinus ± "flow voids" o Look for serpiginous foci in CSF • Leukemia o Usually a dural-based enhancing mass o Commonly hypointense o Most often a complication of acute myelogenous leukemia • Hypertrophic Pachymeningitis o Diffuse dural thickening without known etiology o Involves at least 75% of dural surface o Typically T2 hyperintense o Dense fibrosing pseudotumor may appear "black" (rare) o Diagnosis of exclusion • Extramedullary Hematopoiesis o Juxta-osseous smooth homogeneous masses in chronic anemias or marrow depletion patients

MR Artifacts,

Flow-Related

EXTRA-AXIAL

LESIONS

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c: "

Typically T2 hyperintense; rarely T2 hypointense • Hemangiopericytoma o Lobular, enhancing extra-axial mass with dural attachment, ± skull erosion o May mimic meningioma, but without Ca++ or hyperostosis o Typically heterogeneously T2 hypointense • Retained Pantopaque o Signal parallels fat (shortens Tl/T2) o Usually older patients since not in use since late 1980s o

Alternative

Differential

Approaches

• Diagnosis by signal intensity • "Hypointense" T2 lesions: Meningioma, cellular metastases, schwan noma, lymphoma, leukemia • "Black" hypointense lesions: Air, calcification, (cortical) bone, dense fibrous tissue, flow voids from vessels or CSF flow • Diagnosis by location • Dural lesions: Physiologic Ca++, meningioma, metastases, epidural/subdural hematoma, neurosarcoid, hypertrophic pachymeningitis, extramedullary hematopoiesis • Osseous lesions: Hyperostosis frontalis intern a, metastases, fibrous dysplasia, osseous metaplasia, exostosis, myelofibrosis

MR Artifacts,

Magnetic

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Axial T2WI MR shows hypointense flow-related MR artifact due to CSF pulsations in the premedullary cistern. This artifact is not present on spin echo (Tl)

sequences.

=

Axial T2WI MR shows typical magnetic susceptibility artifact due to aneurysm clips. This artifact is also present close to aerated frontal & temporal bones.

4 69

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Pneumocephalus

Meningioma

(Left) Axial T2' GRE MR shows intraventricular blood SII & pneumocephalus 1:]. Pneumocephalus may be a cause of

II

blooming"

artifact

& multiple" black dots" on T2' (GRE or SWI) scans. (Right) Sagitlal T2WI FS MR shows a T2 hypointense lenlOrial-based mass m. Note lhe lectum [;8 is superiorly displaced A CSF clefl ~ supports the extra-axial location. Flow voids are common in meningioma.

Marked

enhancement

of the mass

was seen (not shown).

'tl

c

III

Metastases, Skull and Meningeal (Left) Axial T2WI MR shows hyperostosis in a plaque-like meningioma along the

=

lefl inner calvarium.

Calcified/ossified meningiomas

rarely enhance

except for a small dural tail.

CT can help exclude a more malignant process. (Right) Axial T2WI MR shows hypoinlenS€ extra-axial masses bilaterally I:] in this patient with osseous & dural metastases. There was

marked enhancement following

contrast.

Note

associated righl-lo-Iefl midline shift

Schwannoma (Left) Axial T2WI MR shows a large hypointense right CPA mass SII. A subtle rim of T2 hyperintense CSF (CSF "cleft") ~ helps to delineate

this as an extra-axial mass. (Right) Axial T2WI MR shows a giant heterogeneously

hypointense

mass which causes mass effect on lhe pons, creales a waist SII as it goes through porus trigeminus into a massively enlarged Meckel cave, trigeminal

I 4 70

schwannoma. The normal left Meckel cave ~ is seen.

12 HYPOINTENSE

,..

EXTRA-AXIAL LESIONS

(fl

c OJ

::l Q.

OJ ..,

Subdural Hematoma,

Mixed

OJ

Saccular Aneurysm (Lefl) Axial T2WI MR shows a hypoinlense subdural hematoma ill lhis trauma patient T2 hypoinlensily may be presenl in subdural

=

hematomas

of varying ages.

(RighI) Axial T2WI MR shows a giant aneurysm of the right middle cerebral artery If thromboses, these may be poorly seen or non-visualized on angiography. Lack of flow arlifact in the phase encoding direction suggests that this aneurysm is lhrombosed. This was conFirmed surgically.

=.

::l

m ~ .., OJ

Q, >< Qi. (fl

"CD OJ

C1

rJl OJ

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(fl C

r::r OJ .., OJ C1

::T ::l

o

0.:

o rJl

CD .., lymphoma,

Metastatic,

Intracranial

::l

Neurosarcoid

rJl

(Left) Axial T2WI MR shows subtle dural-based mass along the right sphenoid wing. NOle similar signal intensity in the involved masticator space E1 & orbit ~. (RighI) Axial T2WI MR shows both Meckel caves are filled with hypoinlense tissue instead of normal hyperintense in lhis

=

=

csr

sarcoid patient Neurosarcoid affecting both trigeminal nerves without other identifiable lesions is unusual.

leukemia

Extramedullary Hematopoiesis (Lefl) Axial T2WI MR shows

a hypoinlense extra-axial bifrontal mass ~ wilh adjacent calvarial destruction related to leukemia in this pediatric

patient

Leukemia

oFten presents as a dural·based enhancing mass. (RighI) Axial T2WI FS MR shows strikingly hypointense

extra-axial masses

= along

the dura in this patient with extramedullary hematopoiesis. These patients lypically have anemia

or another

depletion process.

marrow

I 4 71

HYPERDENSE CSF

C/l C

~ OJ ~ U "0 C

r. t.l

OJ

~ OJ

.0

:::J

(f) "0 C

OJ

o

C/l

Common • Subarachnoid Hemorrhage (SAH), Traumatic • Aneurysmal Subarachnoid Hemorrhage • Streak Artifact • Diffuse Cerebral Edema (Mimic) • Brain Death (Mimic)

OJ t.l

OJ D(f)

OJ

x

, ~ OJ OJ

;( W

t: III

'CO "0

t: III

Less Common • Contrast Material • Chronic Renal Failure • Ventriculitis • Meningitis • Metastases, Meningeal Rare but Important • Nonaneurysmal Perimesencephalic • Superficial Siderosis

SAH

:::J

""(f)

Gyri swollen, cisterns compressed "Cerebellar reversal sign": Density of cerebellum> > hemispheres • Brain Death (Mimic) o Diffuse low density in supratentorial brain causes "pseudo SAH" o Gyri swollen, cisterns compressed o "Cerebellar reversal sign": Density of cerebellum> > hemispheres o Clinical criteria for confirmation o

DIFFERENTIAL DIAGNOSIS

·0

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Subarachnoid Hemorrhage, Traumatic o Peripheral sulci, interpeduncular cistern o Less extensive than aneurysmal blood • Aneurysmal Subarachnoid Hemorrhage o Typically basal cisterns, may be diffuse o Location may indicate causative aneurysm • Streak Artifact o Non-anatomical distribution o Due to metal & dense bone interfaces • Diffuse Cerebral Edema (Mimic) o Diffuse low density in supratentorial brain causes "pseudo SAH" Subarachnoid

Hemorrhage Traumatic

Helpful Clues for Less Common Diagnoses • Contrast Material o Noncontrast CT follows recent contrast procedure (myelogram, cisternogram) • Chronic Renal Failure o Causes contrast recirculation from recent IV contrast injection • Ventriculitis o Ventriculomegaly with debris level, enhancing ependyma • Meningitis o Normal CT or mild ventriculomegaly o May see hyperdense CSF, especially in fungal infections & TB • Metastases, Meningeal o May see hyperdense CSF, effaced sulci Helpful Clues for Rare Diagnoses • Nonaneurysmal Perimesencephalic SAH o Small volume hemorrhage in basal cisterns • Superficial Siderosis o Atrophy; hyperdensity along brain surface

(SAH), Aneurysmal

Subarachnoid

Hemorrhage

I 4 72

Axial NEeT shows extensive traumatic SI\H

1m

&

subdural hematomas ~ Trauma is the most common cause of SAH & is typically less extensive than aneurysmalSAH.

=

Axial N£eT shows cisternal & intraventricular E1 hemorrhage from recent aneurysm rupture. The

location of the blood often indicates the causative aneurysm.

HYPERDENSE

(SF

CIl

"

l: OJ

::::l

a.

Streak Artifact

l:D ...•

Diffuse Cerebral Edema (Mimic)

OJ

(Left) Axial NECT shows a subtle linear hyperdensity in the left frontal extra-axial space 1:1 suspicious for possible acute blood. This was negative on short interim follow-up CT. Streak artifact is typically in a non-anatomic

location.

(Right) Axial NEeT shows multifocal subtle linear foci of high density =:I that may be mistaken for SAH. This is due to residual normal cortex & surrounding diffuse cerebral edema in this near-drowning patient

::::l

m ~ OJ Q,

x

0;' Ul

-0 OJ ()

CD

U> OJ

::::l

a. Ul l:

r::r

...•

OJ OJ

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o

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o U>

CD ...•

Brain Death (Mimic)

::::l

Contrast Material

U>

(Left) Axial NECT shows diffuse edema & complete loss of gray-white matter differentiation which accentuates the vascular structures. The density of the MCAs =:I may also be partly due to stasis or thrombosis. There is a "cerebellar reversal sign" ~ which reflects relative sparing of the

posterior Fossa contents. (Right) Axial NECT shows extensive contrast in the CSF spaces & right temporal horn E!ilI from recent ventriculography.

=

Nonaneurysmal

Peri mesencephalic

SAH (Left) Axial NECT shows increased density within the left sulci &J due to proteinaceous content nearly isodense with the underlying brain. Compare to normal hypodense CSF over the right hemisphere. (RigM) Axial NECT shows minimal prepontine cisternal blood in this patient with a

=

negative

angiogram.

The

volume of blood in perimesencephalic SAH is usually minimal & confined to the basal cisterns.

I 4 73

rn

HYPERDENSE

c ~

EXTRA-AXIAL

MASS(ES)

Q)

~

U u '0 c .r: u

~ CO

.n :::l (/) U C

CO

rn Q) u CO

a. (/)

.~ X

, ~ CO CO

X w c Cll

~

aI

-c

t: Cll

:::l ..ll: (/)

DIFFERENTIAL DIAGNOSIS Common • Subdural Hematoma, Acute • Epidural Hematoma • Meningioma • Metastases, Meningeal less Common • Thrombosis, Dural Sinus • Thrombosis, Cortical Venous • eurosarcoid • Lymphoma, Metastatic, Intracranial • Tuberculosis • Dural A-V Fistula Rare but Important • Extramedullary Hematopoiesis • Leukemia • Venous Varix (Isolated) • Hemangiopericytoma • Malignant Nonmeningothelial

Tumors

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Is it hemorrhage? • Or is it hyperdense mass(es) masquerading as hemorrhage? • CECT/Tl C+ MR helpful in differentiating between the two o 0 contrast-enhancement - hemorrhage o Contrast-enhancement within hyperdense mass excludes simple hemorrhage

Subdural

I 4 74

Hematoma,

Acute

Axial NEU shows a crescentic hyperdense extra-axial fluid collection typical for acute subdural hematoma

Helpful Clues for Common Diagnoses • Subdural Hematoma, Acute o NECT: Homogeneously hyperdense crescent-shaped extra-axial collection o May cross sutures, not dural attachments, may extend along falx & tentorium • Epidural Hematoma o NECT: Hyperdense biconvex extra-axial collection in acute phase o Does not cross sutures unless sutural diastasis/fracture, can cross falx & tentorium • Meningioma o 70-75% hyperdense on NECT, sharply circumscribed smooth mass abutting dura o > 90% enhance homogeneously & intensely on CECT • Metastases, Meningeal o NECT: Hypercellular or hemorrhagic o Skull/dura often/but not always infiltrated o Often known extra cranial malignancy Helpful Clues for less Common Diagnoses • Thrombosis, Dural Sinus o Hyperdensity along expected location of dural sinuses o May be associated with venous infarcts • Neurosarcoid o Multifocal dural-based foci, presence of leptomeningeal enhancement additional clue o Abnormal CXR, raised ESR, ACE levels

Epidural Hematoma

Axial NECT shows a classic epidural hematoma EB

biconvex

hyperdense

HYPERDENSE

EXTRA-AXIAL

,..

MASS(ES)

(JJ

c: III

:J 0llJ

Meningioma

..,

Metastases, Meningeal

III

(Left) Axial NECT in a patient with multiple meningiomalosis syndrome shows several hyperdense, lobulated, dural-based masses Bt,. (Right) Axial NECT shows a mildly hyperdense extra-axial mass overlying the cerebral convexity with adjacent calvaria/thickening [;8 in a patient with a prostate metastasis.

:J

m

~ ~ III x

'"

iii'

en

-0 III (") (1)

en

III

:J 0-

en c: CT III

~

III (")

::T :J Q, 0-

o en

ro~ Thrombosis, Dural Sinus

::J

Tuberculosis

en (Left) Axial NECT shows dural sinus thrombosis with hyperdensity along the expected location of the right transverse sinus ffi (Right) Axial NECT shows a

hyperdense

=:J found

extra-axial mass to be a dural

tuberculoma at surgery (Courtesy R, Ramakantan, MD)

Extramedullary Hematopoiesis

leukemia (Left) Axial NECT shows the typical appearance of extramedullary hematopoiesis with hyperdense, dural-based masses mimicking subdural hematomas in a patient with myelofibrosis. (Right) Axial NECT shows multiple hyperdense extra-axial masses (chloromas) ~ in a patient with leukemia, CECT showed

=

homogeneous enhancement.

I 4 75

en c ~

HYPODENSE

EXTRA-AXIAL

MASS(ES)

Cll

Ul U "0

'0 C

.<:

u

C1l C1l .0

~

OJ (/) "0 C

C1l

en

DIFFERENTIAL DIAGNOSIS Common • Arachnoid Cyst • Subdural Hematoma, Chronic • Post-Operative Epidural Fluid, Effusion, Fat, or Air • Pneumocephalus

Cll

u

C1l 0. (/)

ro .;;: , ['! C1l

x

w c:

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aJ

'tl

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less Common • Neurocysticercosis • Lipoma • Pineal Cyst • Schwan noma • Craniopharyngioma • Epidural Hematoma • Epidermoid Cyst • Rathke Cleft Cyst Rare but Important • Extra-Axial Empyema • Arachnoid Granulations, Dural Sinuses • Dermoid Cyst • Neurenteric Cyst (and Other Epithelial Cysts)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Hypodense extra-axial masses can often be best characterized using FLAIR & DWI MR • Wide window CT settings are important for differentiating air, fat, & water densities • Contrast-enhancement is key for differentiating cystic neoplasm & most infectious etiologies from benign or developmental cysts

I 4 76

Helpful Clues for Common Diagnoses • Arachnoid Cyst o Round/oval CSF density extra-axial mass o May remodel adjacent calvarium 050-60% middle cranial fossa; 10% CPA o DWI, FLAIR MR differentiate from epidermoid cyst • Subdural Hematoma, Chronic o Hypodense, lentiform subdural collection(s) o Can be uni- or bilateral o May be loculated, septated o Can have mixed density fluid-fluid layers o Enhancement along dural margins & septations common

• Post-Operative Epidural Fluid, Effusion, Fat, or Air o Fat/muscle used to repair craniofacial defects may have "mass-like" appearance o Post-operative fluid collections often contain blood products &/or protein resulting in hypodense collections o Surgical or traumatic arachnoid tear may permit CSF to collect in subdural space • Pneumocephalus o Typically related to trauma or post-surgical o Air may become trapped & expand resulting in "tension pneumocephalus" • "Mount Fuji sign": Subdural air separates/compresses frontal lobes, creating widened interhemispheric space between frontal lobe tips that mimics silhouette of Mount Fuji Helpful Clues for less Common Diagnoses • Neurocysticercosis o Convexity subarachnoid spaces most common location o Commonly involves basal cisterns o Racemose form less common: "Grape-like" cystic masses in basal cisterns o Imaging varies with stage & host response • Lipoma o Well-delineated, lobulated, fat density, extra-axial mass o 40-50% along interhemispheric fissure • Peri callosal & cisternal locations are common • Perisylvian location may be associated with seizures o Midline lipomas should prompt search for other abnormalities • Callosal dysgenesis • Azygous anterior cerebral artery • Aneurysms • Pineal Cyst o Homogeneous fluid-filled pineal mass o 25% have associated calcification o Rare enhancement along rim or in adjacent compressed pineal gland • Schwan noma o Most common CPA mass (85-90%) o Enhancing mass with extension into internal auditory canal ("ice cream on cone") o Intratumoral cysts in about 20% of cases o Associated arachnoid cysts rare

en

HYPODENSE EXTRA-AXIAL MASS(ES)

""

r::

• Craniopharyngioma o Calcified, cystic/solid suprasellar mass in a child o Rim &/or solid portions enhance • Epidural Hematoma o Extra-axial biconvex lesion o Usually hyperdense; late subacute/chronic or rapid acute bleeding ("swirl sign") may be partially hypodense • Epidermoid Cyst o Lobulated, insinuating CSF density mass with potential deformity of surrounding structures o DWI MR hyperintensity differentiates from other lesions (arachnoid cyst, cystic mass) • Rathke Cleft Cyst o Sellar/suprasellar cystic mass with intracystic nodule o No calcification or enhancement Helpful Clues for Rare Diagnoses • Extra-Axial Empyema o Subdural much more common than epidural empyema o Peripherally enhancing extra-axial lesion o DWI can help differentiate from other more benign lesions o 15% of cases have both epidural & subdural components o Complication of paranasal sinus disease & bacterial meningitis • Arachnoid Granulations, Dural Sinuses o Fluid signal cysts in or near dural sinuses o No enhancement

Arachnoid

Cyst

Coronal NECT shows an extra-axial CSF collection over the left convexity =::I with local mass effect. Note expansion & thinning of the regional overlying skull 81.

Scalloping of inner calvarium is common • Dermoid Cyst o Fat &/or calcifications are key to diagnosis o Commonly midline location o Look for pathognomonic "fat droplets" in ruptured dermoid cysts • Neurenteric Cyst (and Other Epithelial Cysts) o Neurenteric cyst: Round/lobulated nonenhancing, slightly hyperintense to CSF mass in posterior fossa, typically anterior to pons/medulla o Epithelial cysts not adequately differentiated by imaging: Characterized by histologic wall make-up o Internal signal depends on contents o

Other Essential Information • MR with DWI & FLAIR sequences helpful when considering these diagnoses: Arachnoid cyst, epidermoid cyst, neurenteric cyst, extra-axial empyema

III

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Alternative Differential Approaches • "Cystic" masses: Arachnoid cyst, neurocysticercosis, pineal cyst, schwannoma, craniopharyngioma, Rathke cleft cyst, epidermoid cyst, dermoid, neurenteric cyst • Enhancing lesions: Subdural hematoma, neurocysticercosis, schwannoma, craniopharyngioma, epidural hematoma, extra-axial empyema • DWI MR "bright" lesions: Epidermoid cyst, extra-axial empyema

Subdural

Hematoma,

Chronic

Axial NEeT shows crescentic hypodense extra-axial collection compressing the left hemisphere chronic subdural hematoma. Chronic hematomas & hygromas/effusions may appear similar.

=.

I 4 77

rn

HYPODENSE

<= ~

EXTRA-AXIAL

MASS(ES)

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Post-Operative

Epidural Fluid, Effusion, Fat, or Air

(LeFt) Axial NECT shows a hypodense extra-axial mass anterior 10 both frontal lobes Note that on brain windows, air & fat are not easily differentiated. Bone windows confirm the epidural fat packing. (Right) Axial NECT shows hypodense extra-axial masses bifrontally, characteristic of tension pneumocephalus. Note stretched bridging veins ~ & Mount Fuji sign E:!:2 where the frontal lobe lips resemble the mountain peaks .

=.

'tl

c: III

Neurocysticercosis (Left) Axial CECT shows an extra·axial cyst in the middle cranial

fossa

=

without

enhancement. Racemose or grape-like NCC occurs in the basal cisterns & typically contains no scolex & does not enhance unless there ;s associated meningitis. (Right) Axial NECT shows a midline extra-axial hypodense mass Bone windows (not shown) confirmed fat. Incidentally found lipoma in chis trauma patient. Midline location is typical for these

=.

congenital lesions.

Pineal Cyst (LeFt) Axial NECT shows a small pineal cyst with mild rim calcification. Unless nodularity is present, this is usually incidental, though if over 7 em, serial follow-up studies (over )-] years) is advisable to exclude growth (to avoid missing a cystic pineal tumor). (Right) Axial NECT shows a hypodense mass centered over the 3rd ventricle with a thin rim of

=

calcification

I 4 78

Itl. A cystic

mass, which extended from the suprasellar region, is typical.

Pneumocephalus

HYPODENSE

EXTRA-AXIAL

en

MASS(ES)

"

c:

III

:J

Co

OJ ., III

Epidural Hematoma (Leh) Axial NECT shows a biconvex right frontal mass with a hyperdense inner componenl =:I and hypodense outer component representing a very rapidly bleeding epidural hematoma. (Right) Axial NECT shows CST density extra-axial

mass deforming

the brainstem Insinuating

=:I.

:J

m ~ ~ , Q) Q)

X

iii' (f)

"0 Q)

o en

(1) Q)

:J

margins are

classic for epidermoids. & FLAIR MR confirm diagnosis.

C.

OWl

(f)

c:

0Q)

~ Q)

o

::r :J

o

a: o (ii'

ro~ :J en

Rathke Cleft Cyst (Left) Axial NfCT shows a hypodense suprasellar cyslic mass

1:].

An inlracystic

nodule is commonly seen on MR. No enhancement ;s typical. (Right) Axial CECT shows a lefl fronlal subdural empyema with enhancement along lhe deep margin =:I. A tiny focus of air is seen wilhin the collection Ii8 Underlying left fronlal white mailer hypodensily is consistent with vasogenic edema ~. Associated mass effect is evident

with midline

shifllO the righl.

Arachnoid Granulations,

Dural Sinuses

Dermoid Cyst (Leh) Axial NfCT shows a well-circumscribed round cyst =:I within the superior sagillal sinus which followed CSF, arachnoid

granulation.

The density & location are lhe key imaging findings for lhese lesions, which should nol be confused with

intraluminal thrombus. (Right) /lxial CECT shows a low density pineal

a

region

mass Fat droplets are present in the subarachnoid space =:I. due to dermoid rupture. A shunt is presenllo treat the hydrocephalus,

I 4 79

SECTION 5 Brain Parenchyma, General Generic Imaging Patterns Multiple Enhancing Lesions, General Ring-Enhancing Lesion, Solitary Ring-Enhancing Lesion, Multiple Solitary Cystic Parenchymal Mass, General CSF-like Parenchymal Lesion(s) Cyst with Nodule Fat-like Lesion(s), General

Modality-Specific

1-5-2 1-5-6 1-5-12 1-5-16 1-5-22 1-5-28 1-5-32

Imaging Findings

Solitary Parenchymal Calcification Multiple Parenchymal Calcifications Solitary Hyperdense Parenchymal Lesion Multiple Hyperdense Parenchymal Lesions Solitary Hypodense Parenchymal Lesion Multiple Hypodense Parenchymal Lesions Multiple Brain Hyperintensities (T2/FLAIR), Common Multiple Brain Hyperintensities (T2/FLAIR), Less Common Multiple Brain Hyperintensities (T2/FLAIR), Rare but Important Multiple Hypointense Foci on T2 Multiple Hypointense Foci on GRE/SWI T1/T2 Hyperintense Parenchymal Lesions T1 Hypointense, T2 Hyperintense Parenchymal Lesions T1/T2 Isointense Parenchymal Lesions Restricted Diffusion T1 Hyperintense Parenchymal Lesion(s)

1-5-34 1-5-40 1-5-44 1-5-50 1-5-56 1-5-60 1-5-64 1-5-70 1-5-76 1-5-80 1-5-82 1-5-86 1-5-90 1-5-94 1-5-98 1-5-102

Clinically Based Differentials Brain Tumor in Newborn/Infant Brain Tumor in Child> 1 Year Epilepsy, General

1-5-106 1-5-112 1-5-118

<1l

~

MULTIPLEENHANCING LESIONS, GENERAL

Ql

c Ql

<.9

DIFFERENTIAL DIAGNOSIS Common • Metastases, Parenchymal • Multiple Sclerosis • Neurocysticercosis • Abscess (Multiple)

c: Oro

•...

lD 't:l

c: ra

Less Common • ADEM • Opportunistic Infection, AIDS • Tuberculosis • Lymphoma, Primary CNS • Neurosarcoid • Glioblastoma Multiforme Rare but Important • Vasculitis • Lyme Disease • Lymphoma, Intravascular (Angiocentric) • Parasites, Miscellaneous • Susac Syndrome

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Superficial enhancement is usually vascular or inflammatory • Nodular cortical/subcortical enhancement is characteristic for hematogenous metastases & embolic disease • Ring-enhancing lesions have numerous etiologies: Gliomas (40%), metastases (30%), abscesses (8%), demyelinating disease (6%) • Thick, irregular ("shaggy") rim-enhancing lesions are usually malignant • OWl MR may help differentiate lesions

I 5 2

Helpful Clues for Common Diagnoses • Metastases, Parenchymal o Discrete enhancing parenchymal masses at gray-white interface o Account for up to 50% of all brain tumors o 80% hemispheres, 15% cerebellum, 3% basal ganglia (BG) o Enhancement: Punctate, solid, or ring o Primary tumor often known • Multiple Sclerosis o Multifocal periventricular & callososeptal T2 hyperintensities in a young adult o Active demyelination enhances transiently o Incomplete ring or "horseshoe shaped" enhancement is classic

• May be nodular, ring, or semilunar • Neurocysticercosis o Cyst with scolex in convexity subarachnoid spaces is typical o Four stages: Vesicular, colloidal vesicular, granular nodular, nodular calcified o Vesicular: No enhancement typical; may see discrete, eccentric scolex enhancement o Colloidal vesicular: Thick cyst wall enhances; enhancing marginal nodule o Granular nodular: Thickened, retracted cyst; nodular or ring enhancement o Nodular calcified: Small calcified lesion, rare minimal enhancement • Abscess (Multiple) o DWI + & T2 hypointense rim classic o Four stages: Early cerebritis, late cerebritis, early capsule, late capsule o Early cerebritis: No/patchy enhancement o Late cerebritis: Intense but irregular rim enhancement o Early capsule: Well-defined, thin-walled enhancing rim thicker on side near cortex o Late capsule: Cavity collapses, thickened enhancement of capsule especially side near cortex o Septic emboli ~ multiple lesions Helpful Clues for Less Common Diagnoses • ADEM o Multifocal T2 hyperintense lesions 1-2 weeks after viral infection or vaccination o Variable patterns of enhancement, incomplete ring classic • May be punctate, ring, or peripheral o Predilection for subcortical white matter o Bilateral, but asymmetric lesions • Opportunistic Infection, AIDS o Toxo: Multiple ring-enhancing lesions with surrounding edema in deep & superficial brain typical • Enhancement: Smooth, nodular or target (central nodule & peripheral rim) • Involves BG & gray-white junctions o Aspergillosis: Hemorrhagic, multifocal, poorly defined, enhancing lesions • Solid or rim enhancement • Tuberculosis o TB meningitis is most frequent manifestation, more common in children o Basilar meningitis & parenchymal lesions highly suggestive of TB

MUlTIPLE

ENHANCING

Tuberculomas: Typically parenchymal, supratentorial; solid or ring-enhancing • Lymphoma, Primary CNS o Enhancing lesions in periventricular white matter (WM) or BG o Majority supratentorial but deep gray nuclei are commonly involved o Often involve corpus callosum & extend along ependymal surfaces o Immunocompetent: Strong homogeneous enhancement o lmmunocompromised: Peripheral enhancement with central necrosis or homogeneous enhancement • Neurosarcoid o Solitary or multifocal CNS mass(es) & abnormal CXR classic o Typically leptomeningeal &/or dural enhancement o Rarely causes parenchymal nodules • Glioblastoma Multiforme o Rapidly enlarging malignant tumor characterized by necrosis & neovascularity o Thick, irregular rim enhancement surrounding necrotic core classic • May be solid, ring, nodular, or patchy o Rarely may be multifocal or multicentric o Supratentorial WM most common location

lESIONS,

Metastases,

enhancing

•

•

•

•

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III

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Multiple Sclerosis

Parenchymal

Axial T7 C+ MR shows multiple the corticomedullary junctions, metastatic disease. Significant edema is typical. OWl is typically

Multifocal areas of mildly irregular stenosis alternating with dilated segments o Multifocal subcortical ischemia, ± patchy or gyriform enhancement o DWI + in acute setting Lyme Disease o Lesions simulate multiple sclerosis in a patient with skin rash & flu-like illness o Some enhancement in WM lesions &/or meninges o Cranial nerve enhancement may be seen Lymphoma, Intravascular (Angiocentric) o Multifocal abnormal T2 hyperintensity in deep WM, cortex, or BG o Enhancement: Linear, patchy, nodular, gyriform, homogeneous, meningeal o Supratentorial location typical Parasites, Miscellaneous o Amebic encephalitis: Single or multiple focal, nodular, or ring-enhancing masses o Malaria: Punctate & ring hemorrhages, infarcts, cerebral edema o Paragonimiasis: Conglomerated, multiple ring-enhancing lesions o Trichinosis: Eosinophilic meningoencephalitis, vascular thrombi, infarcts Susac Syndrome o Encephalopathy, visual changes, hearing loss o "Holes" in middle of corpus callosum o Multifocal enhancing WM lesions o

o

Helpful Clues for Rare Diagnoses • Vasculitis o Heterogeneous group of CNS disorders characterized by non-atheromatous inflammation & necrosis of blood vessels

GENERAL

masses at

a classic location for associated vasogenic negative.

Axial T7 C+ MR shows the classic incomplete ring or "horseshoe-shaped" enhancement of demyelination in a patient with MS plaques. enhancement is transient &

indicates active disease.

I 5 3

MULTIPLE ENHANCING

co ~

lESIONS,

GENERAL

Q)

c Q)

c:> co

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Neurocysticercosis

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(Left) Coronal TI C+ Fs MR shows multiple small peripherally enhancing lesions in the subarachnoid spaces relaled 10 nodular calcified slage of NCe. NOle lack of edema. Lesions may be in different

=

stages in the same patient. (Right) Axial TI C+ (5 MR shows mullifocal enhancing

lesions related to septic emboli. OWl is Iypically positive.

Contrast MR mimics

metastases as the lesions are at gray·white

interfaces.

ADEM (Left) Axial T I C+ MR shows mullifocal subcorlical enhancement in this child wilh ADEM. Bilaleral bUI asymmetric involvement is Iypical. The deep gray nuclei are involved in 50% of cases. (Right) Axial TI C+ (5 MR shows multifocal ring-enhancing lesions, some with a classic "target" appearance Ell in Ihis patient with toxoplasmosis. Lesions are most often seen in Ihe BG & cerebral hemispheres. Patients respond well 10 Iherapy.

Tuberculosis (Left) Axial TI C+ MR shows

multiple tuberculomas in the

=

I 5 4

corlex & BG wilh ring & nodular enhancement H2. Classic TB caseating granulomas are T2 hypointense, which helps distinguish them from other enhancing lesions. (Right) Axial TI C+ MR shows solid & ring·enhancing lesions in this immunocompromised patient with primary eNS lymphoma. Ilemorrhage, necrosis, & ring-enhancing lesions are more common in immunocompromised palien/s.

Opportunistic

Infection,

AIDS

MULTIPLE ENHANCING

LESIONS, GENERAL Cll

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Glioblastoma

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Multiforme (Lefl) Axial T1 C+ MR shows nodular & linear enhancement with surrounding edema. Granulomatous leptomeningitis is the most common pathologic feature in neurosarcoid. Leptomeningeal enhancement is characteristic.

Periventricu/ar

WM T2 hyperintensities are seen in approximately 50% of cases. (RighI) Coronal T I C+ MR shows mult/focal enhancing masses related to GBM with involvement of Ihe perivascular spaces.

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Vasculitis (Left) Sagittal T1 C+ MR shows multiple linear enhancing foci. Granulomatous angiitis was found al biopsy. Imaging differential diagnosis includes sarcoid, amyloid angiopathy, vasculitis, & intravascular lymphoma. (RighI) Axial T1 C+ MR shows nodular enhancement & subtle patchy 81 enhancement typical of intravascular lymphoma. This rare diagnosis should be considered in patients with dementia, T2 hyperintense lesions, & enhancement.

(Left) Axial T1 C+ MR shows mulUfocal enhancing lesions in this patient with amebic encephalitis. Note nodular !:ll & ring enhancement typical for this parasite. (RighI) Coronal T1 C+ MR in a 27 year old woman with dizziness, headaches, blurred vision shows multjfocal enhancing lesions

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DIFFERENTIAL DIAGNOSIS Common • Metastases, Parenchymal • Glioblastoma Multiforme • Abscess • Intracerebral Hematoma (Subacute) • Cerebral Infarction, Subacute • Radiation Necrosis less Common • Tumefactive Demyelinating Lesion • Neurocysticercosis • Lymphoma, Primary CNS • Toxoplasmosis, Acquired • Tuberculoma • Aneurysm (Thrombosed) • Arteriovenous Malformation (Thrombosed) • Ganglioglioma • Pilocytic Astrocytoma Rare but Important • Lacunar Infarction (Subacute) • Fungal Diseases • Parasites, Miscellaneous

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Solitary ring-enhancing lesions most often related to tumor, infection, or demyelination • Location of lesion often helpful for diagnosis • Metastatic lesions are typically subcortical, while primary tumors are often deep • Smooth rim enhancement suggests abscess • Irregular, thick rim suggests tumor

I 5 6

T2 hypointense rim & thin enhancing rim DWI + in pyogenic abscess o Look for other signs of infection & source in mastoids & paranasal sinuses o Proton MR spectroscopy (MRS) within pyogenic abscess cavity shows elevated cytosolic amino acids (0.9 ppm), acetate (1.92 ppm), and succinate (2.4 ppm) • Intracerebral Hematoma (Subacute) o History of trauma, coagulopathy, amyloid angiopathy o Ring enhancement common subacutely o Look for blood products on MR (especially on GRE/T2*/SWI sequence) • Cerebral Infarction, Subacute o Signal changes in a vascular territory o May see gyriform Tl hyperintensity o Enhancement: Ring-like &/or gyriform o At this stage, DWT has normalized • Radiation Necrosis o Occurs months after radiotherapy in site of radiation portal o Perfusion MR may discriminate between radiation necrosis & tumor • Radiation necrosis: Hypoperfusion • Tumor: Hyperperfusion o

o

Helpful Clues for Common Diagnoses • Metastases, Parenchymal o Often significant vasogenic edema o Gray-white matter junction typical o Generally does not restrict on DWI o Multiple> single lesion • Glioblastoma Multiforme 095% of primary GBMs have central necrosis, rim enhancement, DWI negative o Heterogeneous white matter (WM) tumor with irregular, thick rim enhancement o Strong tendency to infiltrate widely • Abscess o Can be pyogenic, fungal, or granulomatous

Helpful Clues for less Common Diagnoses • Tumefactive Demyelinating Lesion o Seen in multiple sclerosis & ADEM o Often incomplete ring enhancement, little mass effect or vasogenic edema; resolves with steroid therapy o Often mimics neoplasm • Neurocysticercosis o Cyst with a scolex is pathognomonic o Ring enhancement seen in colloidal vesicular & granular nodular stage • Lymphoma, Primary CNS o Ring-enhancing pattern seen in immunocompromised patients o Typical locations: Periventricular, corpus callosum, basal ganglia (BG) o Hyperdense on CT, hypointense on T2 MR due to hypercellularity o MRS may differentiate from toxo o Lymphoma: Elevated choline level • Toxoplasmosis, Acquired o Solitary or multiple lesions with nodular or ring enhancement o Occurs in immunocompromised, especially HIV+ patients

RING-ENHANCING

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en

SOLITARY

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c:

• Tuberculoma o Associated with TB meningitis in 50% o Can be solitary or multiple • Aneurysm (Thrombosed) o May be partially or completely thrombosed o Laminated appearance of thrombus o May see pulsation artifact on MR • Arteriovenous Malformation (Thrombosed) o May be partiaJly or completely thrombosed o Blood products, calcium are common o Serpiginous nidus seen as flow voids on MR, large draining veins • Ganglioglioma o May be solid, cystic, or mixed solid-cystic o 1/3 have calcifications o Temporal lobes & cerebellar hemispheres most common locations o Temporal lobe lesions present with seizures • Pilocytic Astrocytoma o Common locations: CerebeJlum, hypothalamus, optic pathway o 4 predominant imaging patterns • Mass with enhancing cyst wall & intensely enhancing mural nodule (46%) • Mass with a non enhancing cyst & intensely enhancing mural nodule (21 %) • Necrotic mass with central nonenhancing zone (16%) • Predominantly solid mass with minimal cyst-like component (17%)

o

Associated with neurofibromatosis

type 1

Helpful Clues for Rare Diagnoses • Lacunar Infarction (Subacute) o Typically in BG, thalamus, or deep white matter o May enhance subacutely • Fungal Diseases o Rare infections that occur primarily in immunosuppressed patients o Includes nocardia, blastomycosis, coccidioidomycosis, histoplasmosis, candidiasis o Multiple lesions> single lesion • Parasites, Miscellaneous o Rare infections occur at aJi ages, most common in children & young adults o Patient's travel history important o May cause solitary or multiple ring-enhancing lesions o Amebic encephalitis: Single or multiple nodular or ring-enhancing masses o Paragonimiasis: Hemorrhage or infarct with granuloma formation; ring enhancement

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SELECTED REFERENCES 1.

Smirniotopoulos JG et al: Patterns of contrast enhancement in the brain and meninges. Radiographies. 27(2):525-5 1,2007

Metastases, Parenchymal

Axial T1 C+ [5 MR shows a solitary, thick-walled mass in the right cerebellum A thick enhancing rim suggestsWmor. Biopsy proved metastatic melanoma.

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Coronal T1 C+ M R shows a cystic mass with large mural nodule in the cerebellum 1:]. While this lesion resembles hemangioblastoma, the wall of most cystic hemangioblastomas rarely enhances.

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C

necrosis. CBMs lend to occur in the deep white

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OJ

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matler or deep nuclei & infiltrate widely beyond the enhancing margins. (Right) Axial T7 C+ MR shows a large glioblastoma multiforme E!2 with subependymal involvement Note the irregular

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peripheral

rim enhancement

in the tumor.

Abscess (Left) Axial T7 C+ MR shows a solitary ring-enhancing pyogenic abscess IclJ with perilesional vasogenic edema A smooth, thin enhancing wall & a T2 hypoinlense rim is

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characteristic of abscess. Often abscess walls are thinner along ventricular side, which may predispose to ventricular rupture. (RighI) Axial OWl MR shows a mass demonstrating restricted diffusion on OWl, which is typical of a pyogenic abscess R8

(Left) MRS shows Iypical

MRS

spectrum

of an

abscess

with volume of interest placed within the abscess cavity. MRS was obtained with TR20001TE35. Note the large lactate doublet peak resonating at /.3 ppm A large acetate peak is present at 2 ppm E!2. The peak at 0.9 ppm IJ::l represents cylosolic amino acids (leucine, isoleucine, valine). (Right) Axial CECT shows ring enhancement in a subacute left parietal hematoma 1J::l.

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Glioblastoma

Multiforme

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Cerebral

Infarction,

Subacute

Radiation

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Necrosis (Left) Axial T1 C+ MR shows an evolving infarct in the left temporal lobe ~ that was initially thought to represent a tumor. Follow-up MR (not shown) shows interval lesion involution with resolution of contrasl·enhancemenl.

(Right) Axial T1 C+ MR shows radiation necrosis E2 occurring in the site of a previous arteriovenous malformation

Tumefactive

Demyelinating

Lesion

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Neurocysticercosis (Left) Axial T1 C+ MR shows a biopsy-proven tumefactive demyelinating lesion secondary ta multiple sclerosis. (Right) Coronal T1 C+ MR shows a thick enhancing lesion Note the linear enhancing area that appears ta extend ta the brain surface E:I. This is a

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solitary neurocysticcrcosis

cysllhal is actually within the depths of a sulcus, not actually in the brain parenchyma. The linear enhancement is inflammation

along the pial

surface of the sulcus.

(Left) Sagittal T1 C+ MR shows an irregular ring-enhancing mass in the body of corpus callosum with extension into adjacent

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perivenlricufar

while matter

in an HIV patient. Periventricular

location

may

help differentiate from taxa. (Right) Axial TI C+ MR shows a ring·enhancing mass =:I & ependymal enhancement patient.

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in this II/V

Hemorrhage,

necrosis, & ring-enhancing lesions are common

in

patients with HIV/AIOS who develop CNS lymphomas.

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(Left) Coronal T7 C+ MR shows a left frontal tuberculoma ~. Meningitis occurs in approximately 50% of patienlS with CNS TB. TB is more common in children &, young adullS. (Right) Axial CECT shows an irregular, ring-shaped mass in the suprasellar cistern Note adjacent pial enhancement extending around the suprasellar cistern & into the sylvian fissure m in this patient with suprasel1ar tuberculoma with tuberculous meningitis.

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Aneurysm (Thrombosed)

Aneurysm

Arteriovenous Malformation (Thrombosed)

Arteriovenous

(Thrombosed)

(Left) Coronal T7 C+ MR shows a large extra-axial

basilar artery aneurysm anterior to the pons & medulla =:I with some nodular & rim enhancement. This mass is markedly hypointense on T2 MR. A laminated appearance may help with the diagnosis. (Right) Axial CECT shows ring enhancement in this partially thrombosed "giant" aneurysm (> 2.5 em) =:I. Giant aneurysms are more likely to thrombose.

(Left) Axial CECT shows a

heterogeneous,

ring-enhancing mass =:I with a fluid level SlI related to recent hemorrhage. Note surrounding edema. Thrombosed AVMs account for only 1-2% of all AVMs of the brain. When they occur, they often mimic neoplasm. (Right) Coronal T7 C+ MR shows a partially treated

right parietal arteriovenous malformation

that contains

serpentine flow voids typical of AVM.

I 5 10

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Malformation

(Thrombosed)

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(Left) Coronal T1 C+ FS MR shows a large partially

rim-enhancing cystic mass 8lI in the frontal lobe, compressing the frontal horn of the left lateral ventricfe. There is a strongly enhancing mural nodule within this cystic mass (not shown), typical of ganglioglioma. (Right) Axial T1 C+ MR

Pilocytic Astrocytoma

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Pilocytic Astrocytoma (Left) Coronal T1 C+ MR shows a cavitary cerebe/Jar pHocytic

astrocytoma

with

tumor cyst wall ~ and nodular r.:= enhancement. (Right) Coronal T1 C+ MR shows a ring·enhancing mass with

an

enhancing

mural

nodule that abuts dura. Pilocylic astrocytoma (PA) was found at surgery.

Supratentorial PA are uncommon in the cerebral hemispheres. Differential diagnosis includes ganglioglioma & pleomorphic xanthoastrocytoma.

Fungal Diseases

Parasites, Miscellaneous (Left) Axial T I C+ MR shows an irregular, mildly rim·enhancing mass with surrounding edema & ependymal enhancement Aspergilloma was found at surgery. (Right) Axial T1 C+ MR shows a heterogeneous ring-enhancing mass with mild leptomeningeal enhancement ~. Amebic

=

meningoencephalitis

was

found at biopsy.

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DIFFERENTIAL DIAGNOSIS Common • Metastases Parenchymal • Abscess • Multiple Sclerosis • ADEM • Neurocysticercosis Less Common • Tuberculosis • Opportunistic Infection, AIDS • Lymphoma, Primary CNS • Radiation and Chemotherapy • Multifocal Glioblastoma Multiforme • Subacute Intracerebral Hematomas • Subacute Cerebral Infarctions Rare but Important • Fungal Diseases • Parasites, Miscellaneous • Lyme Disease

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Ring-enhancing lesions are most commonly related to tumor, abscess, & demyelination • Smooth, thin ring enhancement is typical of an organizing abscess • Thick, irregular rings suggest a necrotic neoplasm

I 5 12

Helpful Clues for Common Diagnoses • Metastases Parenchymal o Associated with substantial vasogenic edema for relative size of lesion o Ring-enhancing lesions at corticomedu]]ary junctions • Abscess o Thin T2 hypointense rim characteristic o DWI shows restriction within abscess o Ventriculitis, meningitis may be present o Proton MRS of abscess cavity: Presence of cytosolic amino acids (0.9 ppm), succinate (2.4 ppm), & acetate (1.92 ppm) o Risk factors: Sepsis, immunocompromised, right to left pulmonary shunt o Multifocal disease often caused by septic emboli or paranasal sinus infection • Multiple Sclerosis o Enhancement indicates acute demyelination

Mass effect usually less than expected for size of lesion o Coexistence of enhancing & nonenhancing lesions due to relapsing, remitting nature of disease o Perivenular location "Dawson fingers" & undersurface of corpus callosum typical • ADEM o Usually monophasic o History of recent viral illness or immunization o Multifocal white matter (WM) &/or basal ganglia (BG) lesions o May have with punctate, ring, incomplete ring, or peripheral enhancement o May mimic multiple sclerosis (MS) • Neurocysticercosis o Parasitic infection caused by pork tapeworm, Taenia solium o Cyst with a scolex is pathognomonic o 4 stages: Vesicular, co]]oidal vesicular, granular nodular, nodular calcified o Ring enhancement seen in colloidal vesicular & granular nodular stages o

Helpful Clues for Less Common Diagnoses • Tuberculosis o Associated with TB meningitis in 50% o Caseating TB granulomas often have markedly T2 hypointense centers o Infants, children, & immunocompromised are predisposed o Review CXR to exclude miliary TB or primary TB infection • Opportunistic Infection, AIDS o Multiple ring-enhancing lesions in HIV+ patient: Consider toxoplasmosis, TB, pyogenic/fungal abscess, & lymphoma o Toxoplasmosis is most common opportunistic infection • BG & gray-white matter junctions • Asymmetric "target sign": Enhancing eccentric nodules within abscess cavity o MRS may differentiate Toxo from lymphoma; NAA & choline usua]]y nearly absent (Toxo) • Lymphoma, Primary CNS o Subependymallocation of lesions o Ring enhancement seen in HIV+ patients with lymphoma o MRS: Elevated choline peak o PET: Hypermetabolic

RING-ENHANCING Perfusion MR: Hyperperfusion Radiation and Chemotherapy o Radiation necrosis may cause multiple enhancing lesions o Often difficult to differentiate from recurrent tumor o MRS & MR perfusion may be useful • MRS: No elevated choline • MR perfusion: Hypoperfusion Multifocal Glioblastoma Multiforme o Seen in malignant transformation of low grade glioma & spread of primary GBM o Metachronous lesions uncommon Subacute Intracerebral Hematomas o History of trauma, coagulopathy, amyloid angiopathy o Look for blood products on MR (especially on GRE/T2*/SWI sequence) Subacute Cerebral Infarctions o Exclude vasculitis & embolic phenomenon as cause for multiple infarcts o Enhancement pattern is ring-like & gyriform o Gyriform Tl hyperintensity due to cortical laminar necrosis seen as early as 2 weeks post infarct o Contrast-enhancement of laminar lesions may be seen up to 8 months o

•

•

•

•

lESION,

MULTIPLE

Meningitis common Often multiple ring-enhancing lesions o Most common in immunosuppressed patients • Parasites, Miscellaneous o Amebic encephalitis: Meningoencephalitis; single or multiple focal, nodular, or ring-enhancing masses o Malaria: Punctate & ring hemorrhages, infarcts, cerebral edema, + enhancement • Lyme Disease o Multifocal T2 hyperintense periventricular WM lesions ± enhancement o Cranial nerve enhancement is common o Mimics MS in patient with skin rash & flu-like illness o o

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SELECTED REFERENCES 1.

2. 3.

Smirniotopolllos JG et al: Patterns of contrast enhancement in the brain and meninges. Radiographies. 27(2):525-5 I, 2007 Siskas N et al: Cortical laminar necrosis in brain infarcts: serial MR1.Nellroradiology. 45(5):283-8, 2003 Kamiyama M et al: Cortical laminar necrosis in brain

infarcts: chronological changes on MRI. 39(7):474-9, 1997

ellroradiology.

Helpful Clues for Rare Diagnoses • Fungal Diseases o Includes nocardia, blastomycosis, coccidioidomycosis, histoplasmosis, candidiasis

Metastases Parenchymal

Abscess

I Coronal T1 c+ FS MR shows multiple brain metastases from metastatic breast carcinoma. Significant associated vasogenic edema is common.

=-

Axial T1 C+ MR shows multiple brain abscesses ventriculitis a & meningitis m. Ventriculit.is is a complication of meningitis or a cerebral abscess that

ruptures into the ventricular system.

5 13

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Abscess

Multiple

Sclerosis

(Lefl) Axial T1 C+ MR shows abscesses with thin smooth enhancing waifs The thin waif sugges15infection rather than neoplasm. A T2 hypointense rim & OWl restriction is characteristic of abscess. (Right) Axial T1 C+ MR shows a horseshoe-shaped or U-shaped enhancement typical of demyelinating lesions. Another lesion is partially visualized in this image. Enhancing &

=.

=

nonenhancing

lesions often

coexist in MS.

ADEM

Neurocysticercosis

(Left) Axial T1 C+ MR shows a large, tumefactive ADEM lesion in the left cerebral hemisphere with mild incomplete

enhancement

E!iJ. Mass effect is less than that expected

for lesion size.

Another clue to its nonneoplastic nature is a second lesion on the right ~. (Right) Axial T1 C+ MR shows ring-enhancing right CPA cistern cysts & thickened enhancing meninges E2.

=

Opportunistic (Left) Axial T1 C+ MR shows multiple ring-enhancing foci due to tuberculomas. Caseating tuberculous granulomas with solid centers may be profoundly hypoinlense on T2 MR (not shown). (Right) Coronal T1 C+ Fs MR shows multiple ring-enhancing lesions in

=

=

an

1-11 V

patient

toxoplasmosis.

with An eccentric

target sign may be seen, typical of toxoplasmosis. MRs may help differentiate this from lymphoma.

I 5 14

Infection,

AIDS

RING-ENHANCING

LESION, MULTIPLE

CJl

c: "" III

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(Left) Coronal T1 c+ MR shows ring enhancement in Ihe basal ganglia Hemorrhage & necrosis occur in AIDS-related lymphoma, which leads to ring enhancement AIDS-relaled lymphoma occurs at a younger age than primary CNS lymphoma. (Right) Axial T1 C+ FS MR shows 2 ring-enhancing lesions in Ihe frontal lobes 9: Ihal have been stable for 2 years. These lesions

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within

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portal in this palient with sinonasaf adenocarcinoma.

Multifocal Glioblastoma Multiforme

Subacute Cerebral Infarctions (Left) Coronal T1 C+ MR shows multi/ocal glioblastoma multi/orme ~ in a patient who has previous tumor resection r:=. Ependymal spread is common in GBM. (Right) Sagiaal T1 C+ FS MR shows multiple enhancing watershed infarcts. Some 0/

=

these infarcts demonstrate

gyri/arm T1 hyperintensity (nolshown) secondary to cortical laminar necrosis.

(Left) Coronal T1 C+ MR shows multifocal ring-enhancing

lesions in an

immunocompromised

patient.

Blood cultures were

positive

for Nocardia

rena/transplant

in this

patient.

(Right) Axial T1 C+ MR shows ring ~ & punctate enhancement in this patient with Amebic

encephalitis.

This infection may be focal or diffuse with multiple ring-enhancing

lesions.

I 5 15

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SOLITARY CYSTIC PARENCHYMAL MASS, GENERAL

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DIFFERENTIAL DIAGNOSIS Common • Enlarged Perivascular Space • Encephalomalacia • Neurocysticercosis • Porencephalic Cyst • Glioblastoma Multiforme • Metastasis • Pilocytic Astrocytoma • Abscess Less Common • Intracerebral Hematoma (Resolving) • Multiple Sclerosis • Ganglioglioma • DNET • Pleomorphic Xanthoastrocytoma • Hemangioblastoma • Meningioma (Cystic) • Epidermoid Cyst • Dermoid Cyst • Neuroglial Cyst • Ependymoma, Supratentorial Rare but Important • Parasites, Miscellaneous • Schwan noma (Cystic) • eurenteric Cyst • Desmoplastic Infantile Ganglioglioma

ESSENTIAL INFORMATION

I 5 16

Key Differential Diagnosis Issues • Definition a Includes all cyst-like parenchymal masses a Excludes extra-axial cysts • Cisternal (e.g., arachnoid cyst), intraventricular (ependymal cyst) a Includes "pseudoparenchymal" lesions that can invaginate into brain, mimic cystic parenchymal mass • Epidermoid, dermoid cysts; cystic meningioma • Key clinical issue: Effect of age on diagnosis a Most common in child • Encephalomalacia, infection (abscess, parasite), neoplasm (primary> > metastatic) a Most common in adult • Enlarged perivascular space,

encephalomalacia,

neoplasm (GBM,

metastasis), infection

(abscess, parasite)

• Key imaging issues a Is cystic mass exactly like CSF? • Enlarged perivascular space, encephalomalacia, porencephalic or neuroglial cyst a Is cystic mass hypodense to parenchyma but hyperdense compared to CSF? • Cystic neoplasm, abscess, tumefactive demyelination, epidermoid or neurenteric cyst, parasites a Is density/signal intensity of surrounding brain abnormal? • Encephalomalacia, infection, neoplasm a Does lesion enhance? • Yes: Neoplasm, abscess, resolving (subacute) hematoma, tumefactive demyelination • No: Enlarged perivascular space (PVS), encephalomalacia, porencephalic or neuroglial cyst a Does cyst have mural nodule? • Neurocysticercosis (NCe), neoplasm Helpful Clues for Common Diagnoses • Enlarged Perivascular Space a Multiple lesions, clusters of variable-sized cysts> > solitary enlarged PVS a Well-delineated round/ovoid a Basal ganglia> white matter, midbrain, temporal lobe, dentate nucleus a Follows CSF density/signal intensity • Encephalomalacia a Trauma, infarct, surgery a Follows CSF a Adjacent parenchyma often hyperintense on T2WI, FLAIR • Neurocysticercosis a Multiple small> solitary small or large cyst ± visible scolex a Cyst fluid typically proteinaceous, not exactly like CSF a ± Enhancement, edema a Look for multiple parenchymal calcifications ("starry sky") • Porencephalic Cyst a CSF-containing cyst contiguous with ventricle • Glioblastoma Multiforme a 95% central necrosis ± hemorrhage a Thick, irregular rim enhancement

• Metastasis a

Rim enhances

SOLITARY CYSTIC PARENCHYMAL • Pilocytic Astrocytoma o Child, young adult o Cerebellar cyst + mural nodule • Abscess o Appearance depends on stage o Rim enhancement typical in late cerebritis, capsule stages Helpful Clues for less Common Diagnoses • Intracerebral Hematoma (Resolving) o Slightly hyperdense to CSF on NECT o Hyperintense on Tl-, T2WI o Rim enhancement common • Multiple Sclerosis o "Tumefactive" MS has "horseshoe-shaped" enhancing rim • Ganglioglioma o Cortically based cyst + enhancing nodule o ± Ca++; may remodel skull • DNET o NECT: Cortically based hypodense mass • Hyperdense to CSF o MR: "Bubbly" appearance • Pleomorphic Xanthoastrocytoma o Cortically based cyst + nodule o Look for adjacent "dural tail" • Hemangioblastoma o Middle-aged adult o Posterior fossa cyst + enhancing nodule that abuts pia • Epidermoid Cyst o Irregular "cauliflower-like" margins o Sylvian fissure, quadrigeminal mass can mimic intra-axial mass

Enlarged Perivascular

Space

Coronal T2WI MR shows a solitary cystic left temporal lobe lesion ~ that followed CSF on all sequences. Note the farge pedvascufar space.

MASS, GENERAL

Looks like CSF on NECT Does not suppress on FLAIR,restricts on DWI • Dermoid Cyst o Fat ± Ca++ o Look for fat "droplets" (rupture) • Neuroglial Cyst o Well-delineated CSF-like parenchymal cyst o No enhancement • Ependymoma, Supratentorial o 1/3 of ependymomas o 80% parenchymal, not necessarily related to ventricular wall o Usually large, ± cysts, hemorrhage o Ca++ seen in 50% o Variable heterogeneous enhancement of cyst wall, solid component o

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Helpful Clues for Rare Diagnoses • Parasites, Miscellaneous o Solitary or conglomerate cyst(s) o Some (e.g., hydatid cyst) very large • Schwan noma (Cystic) o Only 1-2% of schwannomas are in brain parenchyma o Peripheral cyst + enhancing nodule • Neurenteric Cyst o Most are extra-axial, posterior fossa o Do occur in supratentorial brain (rare) o Well-delineated cyst hyperintense to CSF • Desmoplastic Infantile Ganglioglioma o Infant with cystic supratentorial mass o Dural-based enhancing mural component

Enlarged Perivascular

Space

Coronal T1WI M R shows a solitary giant midbrain cyst ~ that compresses aqueduct Sl causing obstrucUve hydrocephalus 1:2. Enlarged pial-lined cyst was found at surgery

I 5 17

SOLITARY CYSTIC PARENCHYMAL

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(Left) Axial FLAIR MR in a patient with history of remote

right MCA

infarct

c

shows cystic

[ll

encephalomalacia 81 with spongiosis and gliosis, seen here as FLAIR hyperintensity surrounding the infarcted brain. (Right) Axial CECT in a patient with history of

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systemic cysticercosis and seizure shows a large CSF-like right temporal lobe cyst =:Ii. No other lesions were identified.

(Left) Coronal TI C+ MR shows a large leFt temporal lobe cyst 81 that thins, expands overlying skull =:Ii. NOle compression of the lateral ventricle 1J:ll. Surgery disclosed cyst lined by gliotic brain. (Right) Axial NEeT in patient with two·day history of increasing

headache,

leFt-sided weakness had CT scan to "rule out stroke". NECT shows low density right temporal lobe mass E±. Enhancing rim was seen on TI C+ MR (not shown). Biopsy disclosed glioblastoma mufliforme.

(Left) Axial CECT shows cyslic·appearing mass with thin enhancing rim HI edema Preoperative diagnosis was abscess, but biopsy disclosed

=.

adenocarcinoma.

Right

parahifar mass was Found on chest radiograph. A bronchogenic

I 5 18

carcinoma

primary was diagnosed. (Right) Axial NEeT in a 7 year old shows a hypodense leFt cerebellar mass that is hyperdense compared to CSF Patchy enhancement of solid component [;g was

seen on (fU (no{ shown).

MASS, GENERAL

SOLITARY CYSTIC PARENCHYMAL

en ,.-

MASS, GENERAL

r::

III

:l

C. llJ

... III

(Left) Axial CECT shows ill-defined cyslic lesion with surrounding edema in patient with pyogenic

=

meningitis,

enhancement

in

basilar cisterns E'J. These findings are characteristic of late cerebritis stage of abscess formation. (Right) Axial CECT shows low density mass that is not quite as hypodense as CSf in adjacent

ventricles.

Thin rim

enhancement is seen I:}:I

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3

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IOgether with some adjacent edema 81. MR disclosed features of late subacute

hematoma.

Multiple Sclerosis (Left) Axial T1WI MR shows cyslic-appearing right posterior parieta/lobe mass ~ Several other subtle hypointense lesions are present

Faint rim

enhancement was seen on TI C+ (not shown). (Right) Axial NECT shows hypodense right posterior parietal mass E1 with

=.

extensive

while maller

edema Partial (" horseshoe") rim

enhancement seen on T1 C+ MR is characteristic tumefaCl;ve

of

demyelination.

(Left) Axial T 1 C+ MR shows classic ganglioglioma with cortically based enhancing nodule E:I, nonenhancing cyst (Right) Axial CECT in a 16 year old with long·standing seizures shows nonenhancing cystic·appearing cortical mass Note subtle remodeling 01 adjacent skull 81. Both the patient's history and this CT image are classic ONn

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I 5 19

SOLITARY

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CYSTIC PARENCHYMAL

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0...

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Pleomorphic

Xanthoastrocytoma

(Left) Axial TI C+ MR shows

a cystic mass in right medial

temporal lobe 1:::1 with enhancing cortically based nodule 82. (Right) Axial TI C+ FS MR in a 42 year old shows posterior fossa parenchymal cystic mass 82 with enhancing nodule 1:::1 that abuts pia.

C

nl

(Left) Axial T2WI MR shows hyperintense cystic mass II] with solid dural-based nodule 82. This cystic meningioma

invaginales

into

the brain, making differentiation

between

intra-

and extra-axiallocalion

difficult. (Rigllt) Axial NECT shows left temporal lobe CSF-like mass. Note that the margins are irregular, slightly lobulated 1:::1. Mass did not suppress on FLAIR, showed strong restriction on OWl. Sylvian fissure epidermoid was found at surgery.

Dermoid (Left) Axial NECT shows

calcified hypodense frontal mass 82 that is like fat (not CSF). Note fat droplets in subarachnoid space 1:::1. This was diagnosed as a ruptured dermoid. (Right) Axial FLAIR MR shows a left temporal lobe cyst 82 that suppresses completely on FLAIR. This could be a solitary enlarged perivascular space or neuroglial cyst

I 5 20

Cyst

Hemangioblastoma

SOLITARY CYSTIC PARENCHYMAL

en

MASS, GENERAL

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r::

III

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III ., Ependymoma,

III

Supratentorial (Left) Axial FLAIR MR shows a cyst of CSF-intensity in the right medial temporal lobe These 50-called choroid fissure cysts are probably a variant of arachnoid cyst. (Right) Axial NECT in a young child shows cystic mass in right hemisphere that has solid component 8l Ca++ severe white matter edema. WI 10 grade '" cellular ependymoma was the diagnosis.

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Parasites, Miscellaneous

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Schwan noma (Cystic) (Left) Axial CECT shows a large, unilocular, CSF-like parenchymal cyst without edema or

=

enhancement.

Echinococcus

cysts grow slowly and may attain very large size. (Right) Axial T1 C+ MR shows right occipital cystic mass with a cortically based enhancing nodule 81. Parenchymal

=

schwannoma

was found at

surgery.

(Left) Coronal T1 C+ FS MR shows large, somewhat lobulated, CSF-like, nonenhancing,

intraparenchymal Neurenteric

cyst

=.

cyst found at

surgery. (Right) Coronal T1 C+ MR in infant with large head shows cystic mass with enhancing dural-based nodule (Courtesy M. Sage, MO).

=.

I 5 21

CSF-liKE

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LESION(S)

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DIFFERENTIAL DIAGNOSIS Common • Enlarged Perivascular Spaces • Encephalomalacia • Lacunar Infarction • Neurocysticercosis Less Common • Porencephalic Cyst • Multiple Sclerosis • Normal Variant o Hippocampal Sulcus Remnants o Connatal Cysts Rare but Important • Neuroglial Cyst • Cryptococcosis • Parasites, Miscellaneous • Mucopolysaccharidoses • Germinolytic Cysts • Miscellaneous Congenital

Malformations

ESSENTIAL INFORMATION

I 5 22

• "Clusters" of variably sized CSF-like cysts characteristic • Can occur anywhere but most common locations = basal ganglia, hemispheric white matter, midbrain, dentate nuclei • Variant (mostly in elderly) = "etat crible" ("cribriform state") with multiple tiny cysts in basal ganglia (BG) • Encephalomalacia o Etiology varies (trauma, infarction, etc.) o Can be solitary, multifocal, multicystic o CSF-like ± adjacent FLAIR hyperintensity • Lacunar Infarction o Solitary or multiple o Typically along single long unpaired penetrating arteries &/or vascular watershed zones • BG, thalamus, white matter (WM) common • Multifocal BG infarcts + surrounding gliosis = "etat lacunaire" or "lacunar state" • Neurocysticercosis o Most neurocysticercosis (NCC) cysts are actually in sulci o Cysts in vesicular stage smooth, thin-walled, with scolex generally visible as "dot" within cyst o Multiple lesions in mixed stages common • Some enhance, some do not • Ca++ (multiple = "starry sky" pattern) Helpful Clues for Less Common Diagnoses • Porencephalic Cyst o Communicates with ventricle &/or pial surface o Does not enhance • Multiple Sclerosis o Chronic "burned-out" lesions o Appear as CSF foci with hyperintense rinds on FLAIR/PD o Look for faint hyperintensity surrounding lesions on Tl WI ("lesion within a lesion") o Do sagittal FLAIR or T2WI to look for other lesions along callososeptal interface • Hippocampal Sulcus Remnants o "String of beads" cysts medial to temporal horns of lateral ventricles o Developmental variant, incidental • Remnants of vestigial primary embryonic hippocampal sulcus o Imaging • Between hippocampus, dentate gyrus

CSF-L1KE PARENCHYMAL

• Follow CSF on all sequences • No surrounding gliosis • Connatal Cysts o Single or multiple o Location • Intra- or periventricular (may actually be cysts of anterior choroid plexus) • Small cyst adjacent to tip of frontal horn may be normal anatomic variant o Lined with ependyma o Present at birth o Usually transient o Occasionally seen in older patients o No septations, no hemosiderin o Generally isolated without associated abnormalities Helpful Clues for Rare Diagnoses • Neuroglial Cyst o onenhancing CSF-like cyst o 0 surrounding signal abnormality o Does not communicate with ventricle o Subcortical WM, choroidal fissure common sites • Cryptococcosis o Nonenhancing gelatinous pseudocysts in perivascular spaces (PVS) o Multifocal > > solitary lesions o Most patients have HIV/AIDS • Parasites, Miscellaneous o Other than NCC, parasitic brain cysts uncommon o Hydatid cyst = large non enhancing unilocular cyst

Enlarged Perivascular

Spaces

LESION(S)

• Mucopolysaccharidoses o Multiple, bilateral o Dilated PVSs in deep periventricular WM • Germinolytic Cysts o Periventricular/subependymal cysts • Cyst(s) along caudothalamic groove probably result from germinolysis • Glial (not ependymal) lined cysts/pseudocysts resulting from germinolysis • Distinguish from "connatal" cysts (intraventricular anterior choroid plexus cysts) • Many etiologies, including inherited metabolic disorders (e.g., Zellweger, infantile Refsum), congenital infections (CMV) • eSF-like; ± septations, hemosiderin; do not enhance o Look for associated abnormalities • Leukoencephalopathy • Delayed myelination • Polymicrogyria, pachygyria, heterotopias • Miscellaneous Congenital Malformations o Several have parenchymal CSF-like cysts as part of syndrome • Van der Knaap leukoencephalopathies (megaloencephalic leukoencephalopathy with subcortical cysts, anterior temporal lobe cavitations) • Congenital muscular dystrophy (cerebellar cysts common, may represent dilated perivascular spaces)

Gl Cll

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Cll

Ql

Encephalomalacia

I Coronal T2WI MR shows cluster of variable-sized CSF-like cysts in lefl parieral subcortical white matter m. Lesions did not enhance. Follow-up scan 5 years later showed no change.

Axial TlWI MR in a patient with old left internal artery occlusion shows multicystic encephalomalacia. FlAIR.

5

T2-weighted scans showed extensive hyperinlensity in residual parenchyma

secondary to gliosis, spongiosis.

23

CSF-L1KE PARENCHYMAL

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Q)

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19 ro

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>-

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c ro ~

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(Left) Coronal T7WI MR in an elderly patient with bilateral chronic subdural

hematomas ~

shows

multiple lacunar infarcts ~ in while mailer, basal ganglia. (Right) Axial T7 C+ MR shows several nonenhancing CSF-like cysts ~ of variable sizes in a patient with NCe. Several may be cisternal, invaginating

into brain.

(Courtesy E. Bravo, MO).

(Left) Axial T7WI MR shows fluid replacing a portion of the anteromedia"eft temporal lobe The cystic space communicates with the lateral ventricle ~ and the pial surface of the brain SJ. (Right) Axial FLAIR MR

=.

shows a classic

=

porencephalic cyst that suppresses completely on FLAIR. Some gliosis is present, seen here as a faint area of increased signal intensity SJ.

Multiple Sclerosis (Left) Axial T7 WI MR in a patient with long-standing MS shows multiple hypointense foci that are almost (but not quite) CSF-like. Note the faint hyperintense rims ~ that surround plaques. (Right) Axial TlWI MR in the same patient shows that some lesions are CST intensity SJ. Several others are "bright" but clearly do not

=

resemble the other lesions

SJ or CSF in the lateral ventricles.

I 5 24

Multiple Sclerosis

CSF-L1KE PARENCHYMAL

en ,...

LESION(S)

c: III

::J a.

ro ., III

(Lelt) Axial T2WI MR shows multiple CSF-like cysts in both hippocampi just medial to temporal horns of lateral ventricles. This was an incidental finding on MR . (Right) Axial T2WI MR shows an array of several tiny round and ovoid CSr-like cysts in both hippocampi just medial LO temporal horns of lateral ventricles. FLAIR scan (not shown) demonstrated that the cysts suppressed completely.

=-

Connatal Cysts

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Con natal Cysts (Left) Coronal ultrasound in

a 7 day old premature infant shows a CSF-like intra- or periventricular cyst I:] with a tiny strand of tissue 811 that connects the walls of anterior horn. (Right) SagiLtal T2WI MR in same infant shows that the cyst ~ is definitely CSF-like.

Con natal Cysts (Left) Axial T7 WI MR in an asymptomatic patient shows a CSF-like cyst ~ adjacent to, but separated from, left frontal horn. A smaller cyst present posteriorly (Right) Axial T2WI MR in same patient shows cysts are surrounded by mild hyperintensity 811. Whether these are connalal/germinolytic cysts persisting into adulthood or neuroglial cyst is uncertain. Regardless of etiology, such asymptomatic cysts are benign and typically

nonprogressive.

I 5 25

CSF-liKE

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Neuroglial Cyst

(Left) Axial flAIR MR shows a large cystic mass that suppresses completely but neither enhanced nor restricted. At surgery cyst wall was composed of benign glial cells. (Right) Sagiual T2WI MR shows a variant case of neuroglial cyst that appears to arise from the tectum,

which

appears stretched ~ the cyst.

around

Parasites, Miscellaneous (Left) Axial T2WI MR in patient with HIV/AIOS shows several hyperintense cystic areas, representing dilated perivascular spaces ~J from cryptococcosis. fungi and gelatinous

material

collect within the spaces. There is typically liu/e to no enhancement following contrast administration.

(Right) Axial CECT shows a unilocular cyst in the right cerebral hemisphere with no surrounding edema or enhancement, typical of echinococcus (hydatid disease).

=

Mucopolysaccharidoses (Left) Axial T1WI MR shows multiple enlarged perivascular spaces in this young child with MPS 1H and minimal neurological

symptoms. Note severe perilrjgonal,

callosal

involvement. (Right) Axial FlAIR MR shows] findings typical of mucopolysaccharidosis: CSF-like dilated perivascular spaces filled with mucopolysaccharides ffi hyperintense

while maller,

and global atrophy.

I 5 26

CSF-L1KE PARENCHYMAllESION(S)

CJl

c:: " III

::::l

Co

to ... III

(Left) Axial T2WI MR in an inFant with congenital CMV shows hyperintense germinolytic cysts ~ and extensive perisylvian cortical dysplasia ~. Unexplained periventricular

T2

::::l

to ...ro ::::l -U

ro ... CD

::::l () ::r

hyperintensity perivenlricular cysts, and neuronal migration and

'< 3 ro

organization

G>

abnormalities

should suggest congenital CMV inFection. (Right) Axial T2WI MR in another inFant with congenital CMV inFection shows multiple perivenlricular

cysts

CD

::::l

CD

Q]

germinolytic

ffi

(Left) Coronal fLAIR MR in a patient with inFantile ReFsum disease shows bilateral perivenlricular

germinolytic

a.."

cysts mimicking Zellweger syndrome. (Right) Axial T2WI MR in an inFant with Zellweger syndrome shows germinolytic cysts at the caudothalamic groove The hyperintense white maller

is indicative

demyelination.

of

Also note the

perisylvian polymicrogyria

Ii8

Miscellaneous

Congenital Malformations

Miscellaneous

Congenital Malformations (Left) Axial T2WI MR in a child with congenital muscular dystrophy shows multiple small cystic lesions in the dysplastic cerebellum The pons is hypoplastic with dorsal cleFting ~ Hypomyelination of the temporal lobes is present 81. (Right) Coronal FLAIR MR in an 78 month old inFant with

=.

van der Knaap

leukoencephalopathy shows cystic changes in both temporal lobes

=.

characteristic

condition.

of this

I 5 27

CYST WITH NODULE

['(l Q)

c Q)

(9

DIFFERENTIAL DIAGNOSIS Common • Neurocysticercosis • Pilocytic Astrocytoma • Ganglioglioma • Hemangioblastoma Less Common • Metastases, Parenchymal • Glioblastoma Multiforme • Pleomorphic Xanthoastrocytoma • Abscess • Opportunistic Infection, AIDS, Toxoplasmosis • Parasites, Miscellaneous • DNET Rare but Important • Desmoplastic Infantile Ganglioglioma • Schwannoma, Intraparenchymal • Arteriovenous Malformation (AVM)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Cystic lesions with solid nodular components can be divided into 2 categories o Lesions that typically demonstrate cyst with nodule morphology • Neurocysticercosis (NCC), pilocytic astrocytoma, ganglioglioma, hemangioblastoma, pleomorphic xanthoastrocytoma (PXA), desmoplastic infantile ganglioglioma (DIG), intraparenchymal schwannoma o Lesions that may demonstrate cyst with nodule morphology • Metastases, glioblastoma multiforme (GEM), abscess, toxoplasmosis, parasites, DNET, thrombosed AVM • Although metastases, abscesses, & GEMs do not classically present as "cysts with nodules", they are included because of their overall prevalence o Statistically, the atypical form of these common diseases may be more likely than some of the other "classic" cyst with nodule lesions

I 5 28

Helpful Clues for Common Diagnoses • Neurocysticercosis o Cyst with "dot" inside representing scolex

Imaging appearance varies with stage; increased enhancement & edema when organism dies (inflammatory host response) o Location: Convexity subarachnoid space> > cisterns> parenchyma> ventricles • Pilocytic Astrocytoma o Cerebellar cystic mass with mural nodule in a child; rarely supratentorial o Tl C+: Nodule shows intense but heterogeneous enhancement • Ganglioglioma o Cortically based, slow-growing enhancing mass in older child or young adult o Cyst with nodule most common, may be solid o Most common tumor to cause temporal lobe epilepsy • Hemangioblastoma o Parenchymal posterior fossa cyst with nodule mass in an adult o Tl C+: Nodule abuts pial surface & shows intense, homogeneous enhancement o Multiple in von Hippel-Lindau syndrome (VHL) (25-40% of hemangioblastomas) o

Helpful Clues for Less Common Diagnoses • Metastases, Parenchymal o Discrete, gray-white interface mass(es) with adjacent vasogenic edema o Multiplicity, history of primary malignancy, helpful if present o Solitary metastasis may mimic GEM • Glioblastoma Multiforme o Malignant white matter mass with central necrosis o Predilection to spread across midline along corpus callosum; "butterfly glioma" o Tl C+: Thick, irregular, nodular enhancing margins o T2/FLAIR: Surrounding hyperintensity & mass effect reflect edema + infiltrative tumor • Pleomorphic Xanthoastrocytoma o Cortically based cyst + nodule ± involvement of adjacent meninges o Tl C+ • Enhancing nodule • Look for thickening, enhancement of adjacent meninges • 70% have "dural tail" o Temporal lobe predominance; young adult

CYST WITH NODULE

C/I

c: ""

• Abscess o T2 Hypointense rim with surrounding edema classic o Tl C+: Enhancing capsule thinnest at ventricular side o DWI: Cystic component bright (diffusion restriction) • Opportunistic Infection, AIDS, Toxoplasmosis o Toxoplasmosis: Enhancing central nodules with peripheral rim = "target" lesions o Location: Basal ganglia> hemispheres o Clinical: Immunocompromised patient • Parasites, Miscellaneous o Multiple enhancing lesions typical o May mimic brain tumor o Travel history critical • DNET o Bubbly, wedge-shaped, cortically based mass "points" toward lateral ventricle o T2: Very hyperintense; nodular, septate; no surrounding edema o Tl C+: No to minimal enhancement, may be nodular o Temporal lobe predominance Helpful Clues for Rare Diagnoses

• Desmoplastic Infantile Gangiiogiioma o Supratentorial cystic/nodular mass with dominance of the cyst o Cortically based nodule with intense enhancement & dural tail o May be massive o Peak age 3-6 months

• Schwan noma, Intraparenchymal o Only 1-2% of schwannomas are parenchymal o Cyst with strongly enhancing nodule • Arteriovenous Malformation (AVM) o When hemorrhagic with partial or complete thrombosis, may present as cyst with nodule o Blood breakdown products of various ages; fluid-fluid levels Alternative

Differential

Approaches

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• By location o Posterior fossa: Pilocytic astrocytoma, hemangioblastoma, metastasis o Temporal lobe: Ganglioglioma, pleomorphic xanthoastrocytoma, DNET o Gray-white junction: Metastases, abscess o Hemispheric: NCC, Metastases, GBM, infections, DIG, AVM • Patient age o Child & young adult: Pilocytic astrocytoma, ganglioglioma, PXA, DNET o Adult: Hemangioblastoma, GBM, metastases o Any age: Neurocysticercosis, abscess, other infections • Multiple lesions o Metastases (50-55%), NCC (50-70%), hemangioblastoma (VHL), abscesses (septic emboli), toxoplasmosis, parasites

<1l

::l

...• <1l Q)

Neurocysticercosis

Axial T1WI MR shows a frontal ~ & left laleral ventricular BI "cyst with dot". The "dot", or scolex, may be TI hyperintense Edema &. enhancement vary with stage & host response.

m.

Axial Tl C+ MR shows intense, heterogeneously

a cystic mass ~ enhancing

with an

mural noc/ule

HI

in

I 5

the posterior fossa of a child. Note associated temporal

horn dilatation related to U1etumor.

29

CYST WITH

ro ~

NODULE

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c (l)

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Hemangioblastoma

£

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(Left) Coronal T7 C+ MR shows a circumscribed cystic and solid mass in the tempora/lobe with intense enhancement of the solid mural nodule !:l. Note cortical location and lack of significant mass effect and edema. Gangliogliomas commonly cause temporal lobe epilepsy. (Right) 5agi((al T7 C+ MR shows a cystic mass ~ with an intensely and homogeneously enhancing mural nodule in the posterior fossa of an adult. The nodule typically abuts the pial surface.

a

Metastases,

Parenchymal

(Left) Coronal T7 C+ MR shows a cystic mass with a large enhancing nodule in the cerebellar hemisphere with rim enhancement 11]. This is an atypical appearance for a metastasis. Primary malignancy history & presence of other lesions are helpful for diagnosis. (RighI) Axial CECT shows a heterogeneous mass with irregular peripheral enhancement containing a nodular component ~. Aggressive features help diagnose this malignant

=

tumor.

Pleomorphic (Left) Coronal T7 C+ MR shows a cortically based left temporal lobe cystic mass liB with an enhancing nodule ~ in a young adult. Enhancement & thickening of the adjacent dura !:l help diagnose PXA & differentiate from a ganglioglioma. (Right) Axial T7 C+ F5 MR demonstrates a ring-enhancing lesion with a small enhancing mural nodule!:l. OWl MR (not shown) showed characteristic

I 5 30

diffusion

restriction in the central nonenhancing component.

Xanthoastrocytoma

Abscess

CYST WITH

en

NODULE

c "" ell

::l

a. Opportunistic Infection, Toxoplasmosis

AIDS,

lP .., ell

(Left) COlOnal Tl C+ MR shows basal ganglia, lhalamic, & parenchymal ring-enhancing lesions in

-=

an immunocompromised

::l OJ .., tlJ

::J -U tlJ

patient. Note f1target" appearance with central nodule in the 'ight tempo,allobe lesion. (Right) Axial CECT demonstrates a ring-enhancing lesion with an associated nodule ~ & surrounding vasogenic edema. Multiple punctate lesions are also apparent in this patient with amebic encephalitis.

=

CD ::l ()

::T

'< 3 tlJ

G) CD

::l CD

ill

(Left) Axial Tl C+ MR shows

a left tempo,allobe mass with a small focus of mild enhancement I:] within the bubbly, cystic mass. Faint nodular enhancement can be seen in 20% of ONETs. Lesions a,e typically T2 hyperintense & may erode the adjacent calvarium, as in this case. (Right) Coronal Tl C+ MR shows a large cyst with cortically based, intensely enhancing mural nodule

=

in an infant. Note

=

adjacent dural thickening & enhancement typical of DIG.

Schwannoma,

Intraparenchymal

Arteriovenous

Malformation

(AVM) fLeft} Axial T1 C+ MR shows a cystic parenchymal mass

=

with intensely

enhancing

mural nodule SI in the right occipital lobe. Although ganglioglioma was the pre-operative diagnosis, schwannoma

was found on

pathology. (RigI1l) Axial CECT shows a mixed density cystic and solid lesion with rim enhancement

=.

There

is a lIuid-fluid level within one of the cysts Ell representing

hemorrhage

in

this partially thlOmbosed AVM.

I 5 31

FAT-LIKElESION(S), GENERAL

ro

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..c:: t.l c

~

Ql

ro

0..

c

ro ~ co c 'iij ~

co 't:l

c III

DIFFERENTIAL DIAGNOSIS Common • Choroid Plexus Xanthogranuloma • Lipoma • Craniopharyngioma • Teratoma • Dermoid Cyst • Ossified Falx less Common • Asymmetric Marrow, Petrous Apex • Cholesterol Granuloma, Petrous Apex Rare but Important • "White" Epidermoid Cyst • Meningioma, Lipomatous • Encephalocraniocutaneous • Retained Pantopaque

Lipomatosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Fat vs. cholesterol-containing lesion o Fat (lipoma, dermoid, teratoma) o Cholesterol (craniopharyngioma, xanthogranuloma, cholesterol granuloma) • Fat vs. mimic (lesions with short Tl) Helpful Clues for Common Diagnoses • Choroid Plexus Xanthogranuloma o Common (70% of autopsies) o Incidental MR finding o Older patient with bilateral choroid plexus cysts • Hypodense, Ca++ on NECT

I 5 32

Axial N[CT shows bilateral hypodense, calcified choroid plexus cysts ~ in an elderly paUent. Cysts are xanthogranulomas and look more like CSFthan fat.

• Usually Tl hypointense • Lipoma o Subpial mass (-SO to 100 HU, short Tl) o 50% interhemispheric ± agenesis CC • Craniopharyngioma o Cyst contains high cholesterol fluid o Variable signal on MR • Teratoma o Midline mass with Ca++, adipose tissue • Dermoid Cyst o ± Cisternal fat droplets o NECT: 20-40 HU ± Ca++ o MR: Heterogeneously hyperintense • Ossified Falx o Osseous metaplasia, fatty marrow Helpful Clues for less Common Diagnoses • Asymmetric Marrow, Petrous Apex o Asymmetric aeration o Fatty marrow, no expansile change • Cholesterol Granuloma, Petrous Apex o Expansile PA mass o Tl/T2 hyperintense Helpful Clues for Rare Diagnoses • "White" Epidermoid Cyst o t Protein - short Tl/T2 • Meningioma, Lipomatous o Rare, inhomogeneously hyperintense • Encephalocraniocutaneous Lipomatosis o Scalp lipoma, hemispheric atrophy, variable intracraniaillpomas • Retained Pantopaque o Tl hyperintense; T2 iso-/hypointense o Spine> > > brain

Sagittal T1WI MR shows a small curvilinear interhemispheric lipoma =:I above the corpus callosum.

FAT-LIKE lESION(S),

en ,.-

GENERAL

c: IU

::::l Co

...IU

III

Teratoma (Left) T1WI MR shows classic adamantinomatous craniopharyngioma with striking T 7 shortening caused by thick, brownish ("crankcase") fluid containing high cholesterol. (Right) Sagillal T1 WI MR demonstrates hyperintense fat hypointense focal calcification and soft tissue ~ components in a suprasellar teratoma.

=-

=- =-

Dermoid

::::l

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Cyst

(Left) Sagillal Tf WI MR demonstrates a lesion of mixed signal in the quadrigeminal cistern Q in keeping with a dermoid cyst. There is evidence of rupture with lipid droplets noted throughout the subarachnoid space PJ:?]. A fat-fluid level was present in the lateral ventricle (not shown). (Right) Sagittal T1 WI MR shows hyperintense foci in the midline caused by fatty marrow in the osseous metaplasia i:l2.

Asymmetric

Marrow, Petrous Apex

Cholesterol V

Granuloma,

Petrous Apex (Left) Axial T1 WI MR shows increased signal within leFt petrous apex without expansion. Compare to the normal aerated right petrous apex 81. This is a "leave me alone" pseudolesionl (Right) Axial Tf WI FS MR shows expansile, hyperintense lesion in pelrous apex Lesion did not saturate, which lipoma or fat in asymmetric, unaerated petrous apex would have done.

=

=.

I 5 33

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SOLITARY PARENCHYMAL CALCIFICATION

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DIFFERENTIAL DIAGNOSIS Common • Neurocysticercosis • Tuberculosis • Cavernous Malformation • Oligodendroglioma • Ganglioglioma • Diffuse Astrocytoma, Low Grade • Pilocytic Astrocytoma Less Common • Arteriovenous Malformation • Ependymoma • Parasites, Miscellaneous Rare but Important • Physiologic Calcification, • "Brain Rock" • Calcified Embolus • Saccular Aneurysm • Metastasis, Parenchymal • TORCH Infection • DNET • Meningioangiomatosis

Brain

ESSENTIAL INFORMATION

I 5 34

Key Differential Diagnosis Issues • Solitary brain calcification includes o True parenchymal calcification o Some lesions that may look like they are in brain itself but are not actually in parenchyma • Lesion in deep sulcus (neurocysticercus cyst) • Lesion in vessel (calcified embolus, saccular aneurysm) • Key question: Is Ca++ solitary focus or are there multiple calcified foci in solitary mass-like lesion? • Solitary "dot-like" or globular Ca++ o Typically infectious (neurocysticercosis, TB, occasionally other rare parasites) o Less common • Physiologic (habenular commissure, unilateral basal ganglia) • Vascular (AVM, cavernous malformation, Ca++ embolus) o Rare = brain "rock" • Solitary mass-like lesion with clustered Ca++ o Neoplasm (many) o Cavernous malformation

Helpful Clues for Common Diagnoses • Neurocysticercosis o Nodular calcified (healed) stage o Multiple ("starry sky") > solitary lesions o Most NCC cysts are actually cisternal (within depths of superficial sulci) > brain parenchyma, ventricles • Tuberculosis o Healed gran uloma • Can be single or multiple • Many fewer lesions than CC • Occasionally solitary tuberculoma can be mass-like, mimic neoplasm • Cavernous Malformation o Solitary> multiple o Ca++ can be dot-like, clumped, or scattered within single lesion o Do MR with T2* scan (GRE, SWI) to look for hemorrhage, multiplicity • Oligodendroglioma o Cortical/subcortical mass o Slow-growing; may erode adjacent skull o 70-90% calcify (nodular, clumped) o Adult> child • Ganglioglioma o Slow-growing, cortically based neoplasm o Child/young adult with epilepsy o Common: Ca++ nodule, ± cysts o May erode/remodel adjacent skull • Diffuse Astrocytoma, Low Grade o Hemispheres> posterior fossa o Solid> > cystic mass o 10-20% calcify o Infiltrates brain o Intrinsic tendency to undergo malignant degeneration • Pilocytic Astrocytoma o Cerebellum> optic nerve/chiasm, 3rd ventricle> pons o Cyst with nodule (cerebellum) o Solid mass (optic chiasm/hypothalamus, pons) o Ca++, hemorrhage uncommon (unless pilomyxoid variant) Helpful Clues for Less Common Diagnoses • Arteriovenous Malformation o Little/no mass effect unless hemorrhage o Look for enlarged feeding arteries, draining veins o Occasional Ca++ in nidus, draining veins (phlebolith)

SOLITARY PARENCHYMAL

CALCIFICATION

C/)

~ r::

• Ependymoma o 3rd most common posterior fossa neoplasm in children (after medulloblastoma, pilocytic astrocytoma) 02/3 infra tentorial (4th ventricle) o 1/3 supratentorial (extra-ventricular, hemispheric WM) • Large, extensively calcified cystic/solid hemispheric mass in young child? Think ependymoma first! o 50% of all ependymomas calcify o Cysts, hemorrhage also common • Parasites, Miscellaneous o Except NCC, parenchymal Ca++ rare o Any healed parasitic infection can calcify Helpful Clues for Rare Diagnoses • Physiologic Calcification, Brain o True solitary, unilateral normal parenchymal Ca++ unusual • Basal ganglia usually bilateral, occasionally unilateral • Habenular commissure may Ca++ • "Brain Rock" o Dense globular parenchymal Ca++ o No infection, neoplasm, degeneration • Calcified Embolus o In artery within sulcus, not brain parenchyma • Saccular Aneurysm o Huge, bizarre-appearing, extensively calcified mass in adult? Think partial/completely thrombosed giant saccular aneurysm

• Metastasis, Parenchymal o Untreated metastases rarely calcify o Breast, mucinous carcinoma, osteosarcoma metastasis may calcify spontaneously • TORCH Infection o Multiple> > solitary o CMV most common o Cortical • DNET o Almost all patients < 20 years o Chronic epilepsy o Well-delineated, "bubbly" appearing cortical mass • May remodel overlying skull • Gross Ca++ uncommon, hemorrhage rare • < 20% enhance • May have adjacent cortical dysplasia • Meningioangiomatosis o Child/young adult with seizures o Hamartomatous cortical/leptomeningeal malformation o Meningovascular proliferation along perivascular spaces (PVSs) o 50% associated with neurofibromatosis o Cortical mass with Ca++ (often gyriform) o T2 hypointense o Plaque-like pial, linear enhancement along PVSs

Neurocysticercosis

=-

Nee. No

other brain lesions were identified.

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Neurocysticercosis

Axial N[CT shows solitary calcified NCC cyst probably in depths of sulcus. This was an incidental finding in an immigrant from endemic area who has systemic

ll>

Axial NECT shows small right medial frontal calcification in a patient with known neurocysticercosis. Although lesion looks intraparenchymal, it is most likely within a deep sulcus.

=

I 5 35

SOLITARY PARENCHYMAL

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CALCIFICATION

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Tuberculosis

Tuberculosis

(Left) Axial NECT in patient with known TB shows parenchymal calcification 811 with surrounding hypodensity, characteristic of healed caseating granuloma. (Right) Axial NEeT shows large bifrontal densely calciFied lesion withoul mass eFFect.Note encephalomalacia HJ in adjacent parenchyma. Solitary luberculoma was Found at surgery.

=:2

Cavernous Malformation (LeFt) Axial NEeT in child w/Family history of multiple cavernous malformation syndrome shows solitary, densely calcified right posterior frontal/anterior parietal lobe lesion =:2. One month later lesion hemorrhaged. Cavernous malformation was found at surgery. (Right) Axial NECT shows large solitary hyperdense mass that contains multi(ocal punctate calcifications E:I. "Popcorn"

=:2

appearance

within

hyperdense mass is typical for cavernous

malformation.

Cavernous Malformation (LeFt) Axial NECT shows a partially calcified leFtparietal mass ::3> with edema. MR disclosed cavernous malFormation, but NECT findings are indistinguishable From oligodendroglioma. (Right) Axial NEeT shows cortically based leFt Frontal hypodense mass with calcification Calcification is seen in the vast majority of oligodendrogliomas, typically nodular or clumped.

=.

I 5 36

SOLITARY PARENCHYMAL

CALCIFICATION

CIl

'"

c:

Ganglioglioma (Lefl) Axial CECT shows cystic left parietal mass

m in

with calcification

=

enhancing mural nodule. Ganglioglioma was found at surgery. (RighI) Axial NEeT in child with refractory temporal lobe epilepsy shows calcified temporal lobe lesion =:1 no significant mass effect. Ganglioglioma Solitary calcification

associated

Gl CD

was found at surgery.

::> without

cyst is less

CD

Gl

common appearance.

(Left) Axial NECT shows solitary right thalamic mass with central calcification

clump

=.

of

Note severe

obstructive hydrocephalus with transependymal CSF migration 81. WHO grade /I fibrillary astrocytoma was found at surgery. (RighI) Axial NEeT in a child with headache shows mass with rim =:1 globular 81 Ca++. Pilomyxoid

variant of

pilocytic astrocytoma found at surgery.

was

(Lefl) Axial NECT in a patient with first seizure shows slightly hyperdense right medial temporal lobe mass with focus of globular calcification 81. CECT scans (not shown) demonstrated that the mass consisted of enhancing serpentine vessels

=

characteristic

of an AVM

nidus. (RighI) Axial NECT in a young child shows a large, right hemisphere, multicystic mass with marked surrounding edema and dense clump-like calcification.

Ependymoma

was found at surgery.

I 5 37

SOLITARY PARENCHYMAL

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CALCIFICATION

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Parasites, Miscellaneous (Left) Axial NECT shows a large left frontal mass with extensive rim and globular calcification EJ. (Right) Axial NECT shows a mixed hypo- & hyperdense

=

right posterior

frontal mass

with early clump-like calcification Ameboma was found at surgery.

=.

C

III

Physiologic Calcification, (Lefl) Axial NEeT in a 67 year old woman who presented

with dizziness

shows a solitary "speck" of physiologic calcification in the left basal ganglia EJ. (Right) Axial NEeT shows densely calcified lesion without mass effect Lesion did not enhance on MR.

=

(Left) Axial NECT in a patient with acute right middle cerebral artery territory infarct shows calcification EJ that is actually in M 1 MCA segment. Note distal thrombus in vessel (Right) Axial NECT shows

=

=.

solitary calcification posterior

in right

frontal region

=.

Lesion appears to be at junction but is actually in a small cortical artery within depths of deep sulcus EJ.

gray-white

I 5 38

Brain

"Brain Rock"

SOLITARY PARENCHYMAL

en

CALCIFICATION

c: " III

::::I

Co

.,

lJl

Saccular Aneurysm

III

Metastasis, Parenchymal

::::I

(Left) Axial NECT shows a la'ge, mostly isodense mass

lJl .,

with striking rim calcification

Q)

8l

::::I -0

which proved to be a giani, chronically thrombosed aneurysm . (Right) Axial NECT in a patient with prior brain melaslases from clear cell carcinoma,

primary

site

unknown. Six months after radialion therapy one of the metastases has calcified 1m.

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C1>

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TORCH

Infection

DNET (Left) Axial NECT shows subtle lefl perivenlricular calcificalion Note broad, flal, fronloparielal gyri, suggesling a corlical neuronal migrational abnormalily ~ Note moderate ventricular dilatalion 1!:lI. (Right) Axial NECT shows a hypodense, right posterior fronlallobe, corlically based mass with adjacenl remodeling of lhe calvarium and a dOL of faint calcificalion ~ The diagnosis was ONET.

=-

(Left) Axial NECT in a 75 year old with chronic epilepsy shows dense gyriform calcificalion enlargement of adjacent subarachnoid space m. Meningioangiomalosis found at surgery. (Right) Axial NECT in young adult wilh chronic epilepsy shows

=-

superficial

cortical

=.

calcificalion MR demonstrated enhancing mass in adjacent pia that infiltrated

deep into brain

along perivascular spaces. Meningioangiomatosis identified

I

at surgery.

5 39

[1:1

MUlTIPLE PARENCHYMAL CALCIFICATIONS

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DIFFERENTIAL DIAGNOSIS Common • Normal • Neurocysticercosis • Cavernous Malformation

(Multiple)

Less Common • Tuberculosis • Tuberous Sclerosis Complex • Sturge- Weber Syndrome • Metastases, Parenchymal Rare but Important • Remote Brain Injury • Opportunistic Infection, AIDS • TORCH Infections • Lymphocytic Choriomeningitis • Metabolic (Inherited or Acquired) o Fahr Disease o MELAS o Hypothyroidism o Hyperparathyroidism o Hypoparathyroidism o Pseudohypoparathyroidism oX-linked Adrenoleukodystrophy • Pseudo-TORCH Syndromes • Radiation and Chemotherapy

ESSENTIAL INFORMATION

I 5 40

Key Differential Diagnosis Issues • Discrete, multifocal/scattered Ca++ • Hyperdensities on NECT, variably "blooming" hypointensities on T2*/GRE • Location helpful in differential diagnosis o Basal ganglia (physiologic in adults) • Abnormal Ca++ can be congenital, acquired • End result of toxic/metabolic (e.g., thyroid/parathyroid disorder), inflammatory/infectious etiologies (e.g., TORCH) o Cortex: Neurocysticercosis (sulci), TB, Sturge-Weber o Gray-white junction • Fahr disease • Tuberous sclerosis complex • Metastases (treated> > untreated) • Radiation/chemotherapy o Periventricular • Fahr disease • TORCH, pseudo-TORCH

• Tuberous sclerosis complex Helpful Clues for Common Diagnoses • Normal o Microscopic brain Ca++ ("calcospherocytes") • Ca++, iron deposits in microvessels • Common in elderly, especially basal ganglia (BG) • Except for BG, macroscopic brain parenchymal calcifications usually abnormal o Basal ganglia • Ca++ common in adults • Physiologic> > metabolic derangement (e.g., thyroid/parathyroid disorders) • Uni-/bilateral • Symmetric or asymmetric • Neurocysticercosis o Nodular calcified stage of neurocysticercosis (NCe) o Multiple, small ("starry sky" pattern) > solitary, large Ca++ o Lesions appear to be parenchymal but most actually in depths of sulci! • Cavernous Malformation (Multiple) o Multiple (familial) CM syndrome o 10-30% of cases o Variably-sized hyperdense/Ca++ lesions • Can be small/almost invisible, occasionally very large • Homogeneous or "salt and pepper" o T2* (SWI > GRE) best to detect Helpful Clues for Less Common Diagnoses • Tuberculosis o Ca++ uncommon ('" 20%) • Represents healed granuloma • Solitary> multiple small Ca++ more common • Ca++ often somewhat larger (can be giant) compared to NCC • Few scattered, larger Ca++ (TB) vs. numerous multiple small (NCe) o "Target sign" = central Ca++ surrounded by enhancing rim • Tuberous Sclerosis Complex o 98% have Ca++ subependymal nodules • Most along caudothalamic groove • 30-80% enhance • Enhancing lesion near foramen of Monro needs follow-up (growth indicates subependymal giant cell astrocytoma)

MULTIPLE

PARENCHYMAL

CALCIFICATIONS

CIl

" c:

Tubers in cortex, subcortical white matter • Up to 50% show some Ca++ by age 10 • Enhancement less common (10-15%), does not presage malignancy • Sturge-Weber Syndrome o Gyral (cortex, subcortical white matter) Ca++ (not in pial angioma!) o Atrophy/prominent subarachnoid spaces o Look for enlarged, enhancing ipsilateral choroid plexus, prominent medullary veins o 20% bilateral • Metastases, Parenchymal o Typically post-treatment (e.g., XRT for breast metastases) o Untreated metastases rarely Ca++ o Exceptions • Mucinous adenocarcinoma • Malignant bone neoplasms • Breast (rare) o

Helpful Clues for Rare Diagnoses • Remote Brain Injury o Rare cause of Ca++ o Can occur with trauma, infarction • Opportunistic Infection, AIDS o Most acute, not chronic; Ca++ rare o Co-infection with TB may cause Ca++ if patient survives • TORCH Infections o CMV most common intrauterine infection in developed countries o Others rare (e.g., toxoplasmosis, rubella, herpes)

• Lymphocytic Choriomeningitis o Rodent-borne o Causes necrotizing ependymitis, aqueductal obstruction o Can be indistinguishable from CMV • Fahr Disease o Cerebrovascular ferrocalcinosis o Extensive bilateral BG Ca++ o Can involve dentate nuclei, cerebral white matter • MELAS o Stroke-like cortical, basal ganglionic lacunar infarcts o Basal ganglia Ca++ • Hypothyroidism o May cause BG, cerebellar, subcortical white matter Ca++ • Hyperparathyroidism o Rare; BG Ca++ • X-Linked Adrenoleukodystrophy o Chronic lesions may Ca++ • Pseudo-TORCH Syndromes o Types • Baraister-Reardon • Aicardi-Goutieres o BG, cerebellar> periventricular Ca++ • Radiation and Chemotherapy o Mineralizing microangiopathy o BG, gray-white junction Ca++

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III

Gl C1>

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Neurocysticercosis

Axial NEeT shows multiple calcifications typical for healed cysticercosis. While most lesions look as if they

are in brain parenchyma, many are actually within cerebral sulci.

Axial NEeT scans in same patient at low ventricular fleft), high left frontal (right) regions show healed, calcified TB granulomata 1::1.

I 5 41

MUlTIPLE

OJ OJ

~

PARENCHYMAL

CAlCIFICATIONS

c OJ

(9

Tuberous Sclerosis Complex

Sturge-Weber

Syndrome

(Left) Axial CECT shows multiple parenchyma/l:lll and subependymal calcifications 811. (RighI) Axial NECT shows variant case of Swrge-Weber syndrome with focal sulcal enlargement

ffi

linear

calcifications in underlying thinned cortex SlI. Most patients show much more extensive atrophy and calcification.

Metastases,

Parenchymal

(Lefl) Axial NECT shows untreated calcified metastases in a patient with breast carcinoma, decreased mental status. Multiple lesions enhanced on CECT scan, including these lesions. (RighI) Axial NECT shows focal right temporal lobe infarct as a wedge-shaped area of low density encephalomalacic, gliotic brain 1:llI. Associated dystrophic calcification !J:gI is very rare. Ipsilateral ventricle is mildly enlarged related to volume 1055SlI.

=

TORCH (Lefl) Axial NECT shows extensive perivenlricular. basal ganglia cerebellar IaI calcification. The "primitive" appearance of sylvian cisterns are due to bilateral opercular polymicrogyria ~ (RighI) Axial NECT shows periventricular, thalamic calcifications with venlriculomegaly. Lymphocytic choriomeningilis can mimic cytomegalovirus.

I 5 42

Infections

Remote Brain Injury

MUlTIPLE

PARENCHYMAL

CALCIFICATIONS III

:J

a.

..,

OJ

Fahr Disease

MELAS

III

(Left) Axial NECT shows mulliple nearly symmeuic calcifications in basal ganglia, gray-while malter junclions. (Right) Axial NECT shows bilaleral basal ganglia calcifications

=..

bioccipilal

encephafomalacic

areas

m

in a child with MELAS, mulliple strokes.

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()

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'<

3 OJ

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ID

(Left) Axial NECT shows diffuse hyperdense calcifications

within

basal

ganglia and subcorlical white maller in a patient with proven hypothyroidism. (Right) Axial NECT shows dense laminar calcifications of lentorial dura as well as faint parenchymal calcification in basal ganglia

=

E2.

Pseudo- TORCH Syndromes

Radiation and Chemolherapy (Left) Axial NECT shows brainslem, parenchymal calCIfications more than perivenlricular calci(;cations,

suggesling a pseudo-TORCIf

syndrome such as Aicardi-Coulieres. (Right) Axial NECT shows striking symmetrical calcifications in basal ganglia, gray-white matter junction in a patient who had received prior radialion chemotherapy.

I 5 43

OJ

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SOLITARY HYPERDENSE PARENCHYMAL lESION

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DIFFERENTIAL DIAGNOSIS Common • Cerebral Contusion • Hypertensive Intracranial Hemorrhage • Cerebral Amyloid Disease • Glioblastoma Multiforme • Metastasis, Parenchymal • Thrombosis, Dural Sinus • Thrombosis, Cortical Venous less Common • Cavernous Malformation • Developmental Venous Anomaly • Arteriovenous Malformation • Medulloblastoma (PNET-MB) • Ependymoma, Supratentorial • Melanoma • Ganglioglioma • Lymphoma, Primary CNS • Germinoma • Anaplastic Oligodendroglioma Rare but Important • Drug Abuse • Tuberculoma • Neurosarcoid • Leukemia • Tuberous Selerosis Complex • Meningioangiomatosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Hyperdense parenchymal lesions o t Attenuation compared to normal brain • Caused by o Clotted blood (most common) o Nonhemorrhagic hypercellular (electron dense) mass (less common) o Calcification (excluded here) • History essential o Age o Trauma, hypertension, drug abuse, dementia, known extracranial primary neoplasm o Sudden onset vs. subacute/chronic

I 5 44

Helpful Clues for Common Diagnoses • Cerebral Contusion o Trauma o Location important • Cortex, subcortical white matter

•

•

• •

•

•

• Anterior inferior frontal, temporal lobes most common • Multiple> > solitary lesion o Evolves over time; 24-48 hours existing lesion may enlarge, become more hemorrhagic Hypertensive Intracranial Hemorrhage o Older hypertensive patient o Location important • Deep> superficial lesion • Nearly 2/3 striatocapsular • Thalamus 15-25% o Look for multifocal"microbleeds" • 1-5% • Best seen on T2* MR Cerebral Amyloid Disease o Causes 15-20% of all"spontaneous" intracranial hemorrhages (ICHs) in normotensive elderly patients o Classic = lobar hemorrhage (vs. basal ganglia in hypertension) o Look for "microbleeds" (do T2* MR) • Cortical/subcortical vs. basal ganglia, cerebellum (chronic hypertension) Glioblastoma Multiforme o Necrosis, hemorrhage common Metastasis, Parenchymal o Can be hemorrhagic or non hemorrhagic o Hypercellular, electron dense non hemorrhagic metastases Thrombosis, Dural Sinus o Multifocal > solitary hemorrhage o Parenchymal elot(s) adjacent to dural sinus (transverse sinus> superior sagittal sinus) Thrombosis, Cortical Venous o Multifocal > solitary hemorrhage o Can occur with or without dural sinus occlusion

Helpful Clues for less Common Diagnoses • Cavernous Malfornlation o Variable presentation o Acute hemorrhage • Common cause of spontaneous ICH in children, young adults o Epilepsy • Hyperdense calcified or noncalcified parenchymal mass • Developmental Venous Anomaly o Hemorrhage rare unless mixed with cavernous malformation

SOLITARY

HYPERDENSE

PARENCHYMAL

LESION

CIl

c: ""

Blood in transcortical draining vein slightly hyperdense to brain Arteriovenous Malformation o Common cause of spontaneous ICH in children, young adults o Rupture of intranidal aneurysm, stenosis/occlusion of draining veins Medulloblastoma (PNET-MB) o Electron dense tumor with high nuclear:cytoplasm ratio o Midline hyperdense posterior fossa mass in child? Suspect PNET-MB o Lateral (cerebellar) mass in older child/young adult? Suspect desmoplastic variant of medulloblastoma Ependymoma, Supratentorial o Most ependymomas are intraventricular, but up to 40% are supratentorial, parenchymal> intraventricular o Large hyperdense calcified solid/cystic hemispheric tumor in young child? Think ependymoma! Melanoma o Metastatic> primary CNS melanotic lesion o Melanin or hemorrhage - t density Ganglioglioma o Child/young adult with epilepsy o Most are partially cystic, contain Ca++ Lymphoma, Primary CNS o Corpus callosum, basal ganglia o Hemorrhage rare unless HIV/ AIDS Germinoma o Pineal> infundibulum> basal ganglia o

•

•

•

•

•

•

•

Densely cellular tumor but may also hemorrhage o Hyperdense basal ganglia mass in child/young adult? Think germinoma! • Anaplastic Oligodendroglioma o Mixed density common o May Ca++, hemorrhage o

Helpful Clues for Rare Diagnoses • Drug Abuse o Striatocapsular hemorrhage in young/middle-aged adult? Consider drug abuse • Tuberculoma o Granuloma mildly hyperdense o Can mimic intra- or extra-axial neoplasm • Neurosarcoid o Multifocal > solitary o Extra-axial> parenchymal mass(es) • Leukemia o Extra-axial> intra-axial lesion o Hyperdense parenchymal lesion can be hemorrhagic complication (more common) or chloroma (less common) • Tuberous Sclerosis Complex o Cortical, subcortical tubers can be hyperdense &/or calcified o Multifocal > solitary o Solitary large, "lobar-type" hyperdense tuber ± Ca++ can mimic neoplasm • Meningioangiomatosis o Cortical-based, gyriform hyperdensity o May be densely calcified o Can mimic neoplasm!

Hypertensive

Axial NECT shDws a left frDntal hyperdensity with surrDunding hypodensity, typical Df corUcal contusion. NDte effaced frDntai sulci from focal mass effect.

Intracranial

Gl ctl :J ctl

~ OJ

Hemorrhage

Axial NECT demDnstrates the high density mass

=

wid,

surrounding tow density edema E:I in the most common location for hypertensive hemorrhage. Note compression of the right lateral ventricle by the mass.

I 5 45

SOLITARY

~

HYPERDENSE

PARENCHYMAL

lESION

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E

>-

..c <.l

c

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ctl 0..

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~ IJJ

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=

Cerebral Amyloid Disease

aefOAx~/NECTshows focal lobar hematoma in a 68 yo normotensive, mildly demented patient with sudden onset of right-sided weakness.

T2* MR scan

showed multifocal peripheral black dots" characteristic of amyloid angiopathy. (RighO Axial NECT shows inhomogeneously hyperdense hematoma ~ surrounded by edema MR showed thick, irregular enhancing rind of tissue. Surgery disclosed G8M with intralesional hemorrhage of different ages. ,j

=.

Metastasis, Parenchymal

Metastasis, Parenchymal

Thrombosis, Dural Sinus

Thrombosis, Cortical Venous

(LefO Axial NECT shows right temporal lobe hematoma in this elderfy normotensive nondemented patient wilh decreasing mental status and right 3rd nerve palsy. Hemorrhagic metastasis from unsuspected

=

colon carcinoma

was found

at surgery. (RighO Axial NECT shows hyperdense mass with speckled calcifications [?J. Nonhemorrhagic metastasis from mucinous

=

adenocarcinoma

was Found

at surgery.

(LefO Axial NECT in a postpartum woman wiLh sudden headache followed by seizure shows left posterior temporal lobe hemorrhage 1:1 edema.

Transverse sinus is hyperdense ~.

MR showed

leFt transverse sinus thrombosis. (RighO Axial NECT shows hyperdense left

posterior parietal mass 9. Note superior sagittal sinus ~ appears normal. I lemorrhagic neoplasm was suspected.

I 5 46

Ilemaloma

with

adjacent thrombosed cortical vein was found at surgery.

SOLITARY HYPERDENSE

PARENCHYMAL

en ,...

LESION

c:

III

::::l

Co

Cavernous Malformation

O::J .,

Cavernous Malformation

III

(Left) Axial NECT shows a small, hyperdense left parietal lesion The

=.

diagnosis was cavernous malformation

without

gross

hemorrhage. (Right) Axial NECT in a young girl with 2 day history of headache, visual changes shows mixed

::::l OJ ., OJ

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density lesion in the right occipital lobe MR

OJ

documented hemorrhage but no other lesions. Cavernous

(l)

malformation

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Gl

with acute,

::::l

.,

(l)

subacute, and chronic hemorrhage was Found at

surgery.

(Leh) Axial NEeT shows a rounded, well-delineated, mildly hyperdense lesion in the left cerebellar hemisphere. CECTshowed

=

strong enhancement

with

"Medusa head" dilated venous tributaries.

(Right)

Axial NECT shows mixed density parenchymal hematoma in 24 year old with sudden severe headache, decreased

=

consciousness,

and right 3rd

nerve palsy. DSA disclosed arteriovenous with oullet

malformation vein stenosis.

Medulloblastoma (PNET-MB) (Leh) Axial NECT shows slightly hyperdense mass in the 4th ventricle with solitary faint calcified focus BI. Note obstructive hydrocephalus with dilated temporal horns~. (Right) Axial NECT shows heterogeneously hyperdense partially calcified ~

=

=

periventricular mass with surrounding edema.

Ependymoma adjacent to, but not within, lateral ventricle was Found at

surgery.

I 5 47

SOLITARY HYPERDENSE PARENCHYMAL

ro ~

lESION

Q)

c Q)

t? ro

E

>-

Melanoma

J::

U

~

(Left) Axial NECT in palient with known metastatic

0..

melanoma shows

c

ro ~

hyperdense left temporal lobe lesion (Right) Axial NECT in a 5 year old with

C

possible seizure shows a

III

hyperdense mass that thickens, distorts cortex Lesion showed minimal

C Q)

ro

[IJ

~

al

"0

c

III

=.

enhancement

=.

on MR, and on

NECT, it was indistinguishable from Taylor·type cortical dysplasia.

Germinoma (Left) Axial NECT shows an infiltrating mass 1:1 centered on the corpus callosum, that extends into adjacent deep periventricular

white maller

o( both hemispheres. The

mass is hyperdense compared to white maller, minimally hyperdense compared to cortex. (Right) Axial NECT shows a hyperdense periventricular lesion in the region o( the right caudate head/anterior limb o( the internal capsule.

=

(Left) Axial NECT shows biFrontal hemorrhagic "butterfly" lesion involving corpus callosum Imaging appearance is indislinguishable (rom glioblastoma multiforme, which was the pre-operative diagnosis. (Right) Axial NECT shows striatocapsular hematoma 1:'.1 typical (or hypertensive intracranial hemorrhage. This 22 year old presented to the emergency department with blood pressure 260/720 subsequent to a cocaine

=.

I 5 48

overdose.

SOLITARY HYPERDENSE PARENCHYMAL

en

lESION

" c: III

:J

a.

...

OJ

Tuberculoma

III

Neurosarcoid (Left) Axial NECT shows mixed hyper-, hypodense

mass

=. Tuberculoma

was

found at surgery. (Right) Axial NECT shows hypodense right posterior frontal mass with a mildly hyperdense cortical component 81. MR showed minimal palchy

=

enhancement.

:J

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...

OJ CO

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3 OJ

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Infiltraling

sarcoid was Found at surgery.

CO

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(Left) Axial NECT shows very hyperdense mass in left

cerebral

= with

while maller

adjacent edema ~ in a 79 year old with known history of AML, leukemic relapse,

presented with new onset seizure, right-sided weakness. The finding was presumed chloroma. (Right) Axial NECT shows a variant case of tuberous sclerosis complex with hyperdel1se calcified posterior fossa mass a large cortical ruber.

=-

(Left) Axial NECT shows hyperdense, parlially calcified lobar hamartoma in this patient with

=

tuberous sclerosis complex. This rare manifestation

may

mimic neoplasm. (Right) Axial NECT in a 16 year old with long-standing seizures shows thickened, hyperdense corlex focally effaced sulci. The cortex was hypointense on T2WI, with sulcal hyperintensity and

=-

enhancement

on MR.

I 5 49

ro ~

MULTIPLE HYPERDENSE

PARENCHYMAL

LESIONS

Ql

c Ql

C)

ro

E

>, .r: c

'-'

~ Ql

ro

11.

c

ro ~ co C III

~ III "t:l

c

III

Common • Cerebral Contusion • Diffuse Axonal Injury (DAI) • Hypertensive Intracranial Hemorrhage • Cerebral Amyloid Disease • Metastases, Parenchymal • Cavernous Malformations

I 5 50

•

Less Common • Cerebral Infarction, Subacute • Thrombosis, Cortical Venous • Acute Hypertensive Encephalopathy, PRES • Anticoagulation Complications • Glioblastoma Multiforme • Lymphoma, Primary CNS • Tuberous Sclerosis Complex

•

Rare but Important • Tuberculomas • Neurosarcoid • Leukemia • Thrombotic Microangiopathies (HUS/TTP) • Thrombolysis Complications • Parasites, Miscellaneous • Acute Hemorrhagic Leukoencephalopathy

•

ESSENTIAL INFORMATION

Other: Corpus callosum, deep gray nuclei, midbrain/brainstem o T2* scan (GRE/SWI) helpful Hypertensive Intracranial Hemorrhage o Solitary hematoma> patchy/multifocal hemorrhage o Deep> superficial lesions • Nearly 2/3 striatocapsular • Thalamus 15-25% o Look for multifocal"microbleeds" (1-5%), best seen on MR with GRE/SWI sequence • Basal ganglia, cerebellum (vs. cortical, peripheral in amyloid) Cerebral Amyloid Disease o Causes 15-20% of primary non traumatic intracranial hemorrhage in older patients o Classic = lobar hemorrhages of different ages o Most common manifestation actually "microbleeds" • Do T2* (GREor SWI) scan to detect Metastases, Parenchymal o Electron dense (hypercellular or hemorrhagic) o Some enhancement usually present Cavernous Malformations o Multiple (familial) lesions o NECT often normal unless acute intralesional hemorrhage o Iso-/hyperdense ± Ca++ o Mass effect absent unless hemorrhage o Do MR with T2* (GREor SWI) for optimal imaging o

DIFFERENTIAL DIAGNOSIS

•

Helpful Clues for Less Common Diagnoses • Cerebral Infarction, Subacute o Hemorrhagic transformation • Typically 2-3 days after ischemic infarct • Patchy petechial hemorrhages in cortex, basal ganglia • Thrombosis, Cortical Venous o With or without dural sinus thrombosis o Patchy cortical/subcortical petechial hemorrhages • Acute Hypertensive Encephalopathy, PRES o Most common: Patchy hypodense cortical/subcortical foci • Occipital lobes > basal ganglia> brainstem, cerebellum o Less common: Petechial hemorrhages (gross hematomas rare)

MULTIPLE

HYPERDENSE

PARENCHYMAL

LESIONS

en

" c:

• Anticoagulation Complications o Mixed density hemorrhages o Fluid-fluid levels, unclotted blood • Glioblastoma Multiforme o ecrosis, hemorrhage common • Low density center, thick irregular high density hypercellular rim o Multifocal GBM, "butterfly" GBM of corpus callosum • Both can appear to have separate hyperdense regions • Can be either hemorrhage or hypercell ular regions • Lymphoma, Primary CNS o Iso-/hyperdense lesions in corpus callosum, basal ganglia, periventricular WM o Frank hemorrhage? Suspect HIV/ AIDS • Tuberous Sclerosis Complex o 98% have Ca++ subependymal nodules o Some cortical, subcortical tubers calcify o Occasional noncalcified cortical, subcortical hyperdensities seen Helpful Clues for Rare Diagnoses • Tuberculomas o Meningitis> parenchymal lesions o Mildly hyperdense (rim> solid) ± edema o Healed granulomas may calcify • Neurosarcoid o Infiltrates along perivascular spaces -> parenchymal mass o May cause focal patchy hyperdense mass(es)

Cerebral Contusion

• Leukemia o Most parenchymal hyperdensities are hemorrhages o Hypercellular parenchymal masses (chloromas) < extra-axial tumor • Thrombotic Microangiopathies (HUS/TTP) o Thrombocytopenia, intravascular hemolysis characteristic of 3 disorders • Malignant hypertension (often with HUS) • Disseminated intravascular coagulation (DIC) • Thrombocytopenic thrombotic purpura (TIP) o Patchy petechial hemorrhages, predominately cortical • Thrombolysis Complications o 10-lS% hemorrhage • Petechial> gross lobar o Post-procedural T1 C+ MR may predict hemorrhagic transformation (HT) • If present, risk of HT t • Parasites, Miscellaneous o Cysts> hyperdensities o Consider travel history, especially in endemic area o Beware: Conglomerate parasitic masses can mimic brain tumor! • Acute Hemorrhagic Leukoencephalopathy o Fulminant variant of ADEM o Hyperintensities in/along perivascular spaces o Microhemorrhages > gross lesions oCT, MR may not show hemorrhage

Ql

:I

a. III ..., Ql

:I III ..., Q)

:I

-U

..., Q)

CD :I ()

:r '<

3

Q)

G) CD :J

...,

CD Q)

Diffuse Axonal Injury (OAf)

=

Axial NECT shows several hemorrhagic contusions in the inferior frontal lobes, anterior right temporal lobe, and posterior righllemporal lobe.

=-

Axial NECT shows scattered hyperdense foci of OAI at gray-white interfaces left thalamus Sl and midbrainP.::D.

I 5 51

MULTIPLE HYPERDENsE PARENCHYMAL

co ~

lESIONS

QJ C QJ

o co

E >,

-'u= c QJ

~ co 0-

c

co ~

[D

c co •...

[JJ

"tl

c

III

(Left) Axial NECT shows a large high density mass in the leit cerebellar hemisphere =:I. The right cerebellar hematoma oi slightly lesser increased attenuation ~ indicates active hemorrhage. (Right) Axial NECT in a hypertensive patient shows patchy pontine =:I and cerebellar hemorrhages PJ:].

Cerebral (Left) Axial NECT shows spontaneous leitlobar hemorrhage =:I in a demented, normotensive patient. (Right) Axial NECT at a higher level in the same patient shows a right lobar hemorrhage =:I. Multiple lobar hemorrhages suggest amyloid angiopathy.

(Left) Axial NECT shows a heterogeneous, slightly hyperdense lesion in the leit temporal lobe, with a central iocus oi hemorrhage ~ and surrounding vasogenic edema. This patient has metastatic

=

bronchogenic

carcinoma.

(Right) Axial NECT in the same patient shows 2 other slightly hyperdense lesions =:I in the leit iron tal lobe, one with central hemorrhage

ffi

Significant

vasogenic

I 5 52

surrounding

edema is present.

Amyloid

Disease

Cerebral Amyloid

Disease

MUlTIPLE

HYPERDENSE

PARENCHYMAL

en ,..

LESIONS

c: III

::::l Q.

..,

OJ Cavernous Malformations

III

(Left) Axial NECT shows faint hyperdensities in the septum pe//ucidum and left medial frontal cortex MR with SWI showed multiple cavernous malformations mixed with large venous malformation. (Righi) Axial NECT in a child with known multiple cavernous malformation syndrome shows 2 faint hyperdense lesions in left parietal lobe.

=.

=

::::l

..,

OJ Ql

::::l II

..,

Ql

::::l ::r

()

'<

3

Ql

G)
::::l

..,
Ql

(Left) Axial NECT obtained one week after acute ischemic

inFarction shows

hemorrhagic transformation, seen here as mulLifocal gyriform hyperdensities (Right) Axial NECT shows acute thrombosis of the superior sagittal sinus ~ with multifocal cortical/subcortical hemorrhages caused by cortical vein occfusions.

=.

=

Acute Hypertensive Thrombosis,

Cortical

Venous

Encephalopathy,

PRES (Leh) Axial NECT shows multiple hemorrhagic fod in the left temporal lobe MR disclosed thrombus in

=.

the left transverse sinus that extended into a large anastomotic vein of Labbe (VorL), causing massive parenchymal hemorrhages. This location is very characteristic of VorL occlusion. (Right) Axial NECT in 24 year old renal transplant patient on cyclosporine shows bilateral hypodensities in both occipital lobes with hemorrhagic foci Ell.

=

I S 53

~ Q)

MUlTIPLE

L

HYPERDENSE

PARENCHYMAL

LESIONS

---!

c Q)

<.9
E >-

.r:: ()

~

ro Cl..

c ~ III

c ~

CD "'C C III

(Lefl) Axial NECT in this 71 year old woman with laboratory-documented coagulopathy shows bilateral intracerebral hematomas with blood-fluid levels (RighI) Axial NECT shows bilateral hemorrhages E:I into "butterfly" lesion of the corpus callosum genu.

=.

Tuberous Sclerosis Complex (Left) Axial NECT shows 2 hyperdense periventricufar lesions It] with some surrounding vasogenic edema. These lesions are hypercellular, not hemorrhagic. (RighI) Axial NECT shows multifocal, discrete, hyperdense, non calcified subcortical hyperdensiUes Other scans showed typical calcified subependymal nodules.

=.

Tuberous Sclerosis Complex (Lefl) Axial NECT in a child with known tuberous sclerosis complex shows hyperdense masses in thickened cortex and basal ganglia The tuber in the caudate head is partially calcified E:I. (RighI) Axial NECT shows left frontal edema adjacent to several ring-like hyperdense lesions BiI in patient with known tuberculous

=.

=

meningitis.

I 5 54

Tuberculomas

MULTIPLE

HYPERDENSE

PARENCHYMAL

en

lESIONS

"

l: III

::l Co

..,

OJ III

(Left) Axial NECT shows hype,dense right occipital lesions 6tIthat showed strong but patchy enhancemenl.

neurosarcoid

Infiltrating

was proven at

biopsy. (Coullesy M. Hemmati, MDJ. (Right) Axial NECT shows extensive

lJJ .., OJ

::l -0

..,

OJ C1l

::l ()

::T '<

3

multiiocal pa,enchymal hemo(lhages in a ,apidly

OJ

deteriorating

C1l

teenager

with

acute myelogenous leukemia who presented in the emergency department with visual problems. CBC revealed the patient had almost no platelets.

Thrombotic

::l

Gl ::l

..,

C1l OJ

Microangiopathies (HU5/TTP) (Left) Axial NECT in septic patient

with disseminated

intravascular coagulopathy shows multiiocal petechial hemo(lhages p,edominately right irontal

=-

with lesser involvement

of

leit irontallobe 81. Innumerable bilateral cortical infarcts were seen on OWl.

(Right) Axial NECT obtained several hours after thrombolysis ior M 1 MCA

thrombus with ischemic territorial

infarction

shows

petechial hemo(lhages

Parasites, Miscellaneous

=.

Acute Hemorrhagic Leukoencephalopathy (Leit) Axial NECT shows patchy hyperdense lesions in the right posterior irontal lobe Amebiasis was iound at surgery. (Right) Axial NECT was obtained just prior to death in this 70 year old patient patient with

=.

mullifocal

hyperinlensilies

along perivascular spaces, as seen on MR. Diiiuse brain swelling but no iocal hemorrhages

were seen.

Autopsy iound acute hemo(lhagic leukoencephalitis.

I 5 55

SOLITARY HYPODENSE

CIl

E

>-

J::

U C Ql L-

CIl

Cl..

c CIl L-

en c ns ...

aJ "'C C

ns

DIFFERENTIAL DIAGNOSIS Common • Cerebral Contusion • Cerebral Ischemia-Infarction, Acute • Cerebral Infarction, Subacute • Cerebral Infarction, Chronic • Glioblastoma Multiforme • Anaplastic Astrocytoma • Metastasis • Oligodendroglioma Less Common • Diffuse Astrocytoma, Low Grade • Pilocytic Astrocytoma • Cerebritis • Encephalitis • Intracerebral Hematoma (Resolving) • Thrombosis, Cortical Venous Rare but Important • Multiple Sclerosis • ADEM • Tuberculoma

ESSENTIAL INFORMATION

I 5 56

Key Differential Diagnosis Issues • Definition o Includes solitary focal hypoattenuating parenchymal lesions that are hypodense to brain but hyperdense compared to CSF o Excludes cysts, cyst-like lesions o Excludes multifocal, diffuse/confluent white matter diseases • History key o Trauma (contusion, resolving hematoma)? o Sudden (e.g., stroke) vs. gradual onset (tumors, infection, demyelinating diseases) • Effect of age on differential diagnosis o Child • Diffuse astrocytoma, low grade • ADEM o Adult • Multiple sclerosis • ADEM • Glioblastoma multiforme • Anaplastic astrocytoma • Metastasis o Both • Contusion • Infection (cerebritis, encephalitis)

PARENCHYMAL

LESION

• Cerebral ischemia-infarction child)

(adult>

Helpful Clues for Common Diagnoses • Cerebral Contusion o Cortical/subcortical hypodensity o ± Petechial hemorrhages o Multifocal > solitary, confluent o Look for • Overlying scalp swelling (coup) or opposite lesion (contrecoup) • Adjacent traumatic subarachnoid hemorrhage o Lesions "bloom" (become more prominent) with time • Cerebral Ischemia-Infarction, Acute o Look for dense MCA, dot signs o Subtle effacement of gray-white interfaces • Insular ribbon sign • Hypodense/"smudged" basal ganglia • Cerebral Infarction, Subacute o Hypodensity increases o Mass effect increases o Wedge-shaped hypodensity in vascular distribution o Involves both gray, white matter; extends to cortex • Cerebral Infarction, Chronic o Gliotic, encephalomalacic brain o Hypointense on FLAIRbut often has hyperintense borders • Glioblastoma Multiforme o Glioblastoma multiforme (GBM) usually tumor of middle-aged, older adults o 95% central necrosis, thick enhancing rind, edema o Ca++ rare; gross hemorrhage common • Anaplastic Astrocytoma o Poorly-delineated, infiltrating o Ca++, hemorrhage less common o If any enhancement, suspect GBM • Metastasis o Iso- to hypodense mass, variable edema o Enhances (solid, ring, nodular) • Oligodendroglioma o Hypodense cortical/subcortical mass o 50% calcify o Enhancement variable Helpful Clues for Less Common Diagnoses • Diffuse Astrocytoma, Low Grade o Hypodense, nonenhancing o 2/3 supratentorial (hemispheres)

SOLITARY HYPODENSE 1/3 posterior fossa (brainstem, cerebellum) Pilocytic Astrocytoma o Cerebellum = cyst + nodule o Hypothalamus/optic pathway • Lobulated hypodense mass • Enhances strongly, uniformly Cerebritis o First, earliest stage of abscess formation o Poorly marginated hypodense mass o Enhancement none or minimal Encephalitis o Mostly viral • General imaging findings = hypodense mass, variable enhancement o Herpes encephalitis most common • Limbic system predilection (both temporal lobes, cingulum, subfrontal cortex) • Cortex, subcortical white matter • Enhancement, hemorrhage absent in early stage • MR with FLAIRmost sensitive Intracerebral Hematoma (Resolving) o Hypodense to brain but hyperdense to CSF o May show ring enhancement o MR shows evidence for resolving hemorrhage Thrombosis, Cortical Venous o Can be solitary or multiple o Can occur with or without associated dural sinus occlusion o May show "cord sign" (thrombosed cortical vein) o

•

•

•

•

•

=

Axial NEeT in this patient 24 hours after trauma shows

extensive cortical/subcortical hypodense mass with petechial hemorrhages ~. Note intraventricular blood-fluid level r=;J.

PARENCHYMAL o o o

Ul

lESION

c" :

Hypodense cortex/subcortical white matter lesion(s) Patchy petechial hemorrhage common Do CECT/CTV

III

::;, 0-

..•

lJl III

::;,

oMR

• Include T1 C+ • Do T2* (GRE/SWI), look for blooming clot in thrombosed cortical vein Helpful Clues for Rare Diagnoses

• Multiple Sclerosis o Multiple> solitary lesion o Solitary tumefactive MS plaque can mimic neoplasm o Hypodense on ECT o MR

• Do sagittal FLAIR • T1 C+ may show "horseshoe" enhancement • ADEM o Follows viral illness, vaccination o Multifocallesions > solitary o Solitary tumefactive demyelination can mimic neoplasm • Tuberculoma o Can be parenchymal or dural-based mass o Can be hyper- or hypodense or mixed o Variable enhancement (can mimic neoplasm)

=

Axial NEG shows hypodense right insular lesion with loss or gray-white dirrerenUation("insular ribbon sign") in this elderly patient who presented to the emergency

department

with acute stroke symptoms.

I 5 57

SOLITARY

C1l

~ Q)

HYPODENSE

PARENCHYMAL

LESION

C Q)

C)

Cerebral

Infarction,

Subacute

Cerebral

Infarction,

Chronic

(Left) Axial NECT 2 days after a stroke shows well-demarcated hypodensity in the cortical territory of the leFt middle cerebral artery 1:]. (Right) Axial NECT shows encephalomalacia I:] in leFt MCA distribution. Note enlargement

=

'-=

of lateral

ventricle secondary volume loss.

to

Glioblastoma

Multiforme

(Left) Axial NEC!, in a 65 year old in the emergency department with progressive headache & leFt-sided weakness; was obtained to "rule out stroke". It shows hypodense right temporal lobe mass 1:1 hypedense to C5f MR (not shown) disclosed enhancing rind around non enhancing center of mass. (Right) Axial CECT in a child shows a hypodense nonenhancing mass that enlarges the pons, flattens & compresses the 4th ventricle 1:]. /-ligh grade glioma was Found at biopsy.

Oligodendroglioma (Left) Axial CECT shows nonenhancing,

noncalcified

hypodense leFt Frontal mass I:] that involves both corlex and subcortical

white maller.

Oligodendroglioma with no atypical Features was Found at surgery. (Right) Axial CECT shows a hypodense diFFuselyinfiltrating non enhancing white matter mass I:] in leFt Frontal lobe. The cortex appears relatively spared in this patient with W/-IO grade II astrocytoma.

I 5 58

Diffuse Astrocytoma,

Low Grade

SOLITARY HYPODENSE

PARENCHYMAL

lESION

VI

c: " III

::J

0. III .,

Cerebritis

III

(Leh) Axial NECT in this 3 year old shows large lobulated hypodense mass 1m centered in the hypothalamus. MR showed that the mass enhanced strongly, uniformly. (Right) Axial NECT in teenager with 2 day history of headache, nausea, & vomiting shows an ill-defined hypodense area in right posterior temporal lobe =:2. OWl restriction, early rim enhancement were seen on MR (not shown).

Thrombosis, Cortical

::J III ., III

::J -U III

~ CD ::J

()

::r

'< 3 III

G) CD ::J

CD

OJ

Venous (Left) Axial NECT shows relatively well-delineated hypodense right hemisphere mass ~ that is not quite CSF-like. CECT (not shown) demonstrated rim enhancement;

T 1 WI showed

lesion contained homogeneously hyperintense fluid consistent with dilute free methemoglobin. (Right) Axial NECT in patient with occluded vein of Labbe shows hypodense left posterior temporal venous infarct with patchy hemorrhage 81.

=:2

Multiple

Sclerosis

ADEM (Left) Axial NECT shows a low density lesion isolated to the left frontal white matter in a patient with multiple sclerosis. (Right) Axial NECT shows a large, tumefactive ADEM lesion =:2. MR demonstrated "horseshoe" enhancement around the lesion margins.

=:2

I 5 59

~

MULTIPLE HYPODENSE PARENCHYMAL LESIONS

C

<.9

..

DIFFERENTIAL DIAGNOSIS Common • Cerebral Infarction • Trauma o Cerebral Contusion o Diffuse Axonal Injury (DAI) • Metastases, Parenchymal

C l'Cl

aI "'C

c l'Cl

Less Common • Multiple Sclerosis • Infection o Encephalitis (Miscellaneous) o Abscesses o Opportunistic Infection, AIDS o Tuberculosis • ADEM • Acute Hypertensive Encephalopathy, • Vasculitis

PRES

Rare but Important • Glioblastoma Multiforme • Osmotic Demyelination Syndrome • Tuberous Sclerosis Complex • Lyme Disease • Systemic Lupus Erythematosus • CADASIL • Rickettsial Diseases • Lymphoma, Intravascular (Angiocentric)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Includes multiple parenchymal lesions hypodense to brain but hyperdense compared to CSF • Cysts & cyst-like lesions are excluded

I 5 60

Helpful Clues for Common Diagnoses • Cerebral Infarction o Wedge-shaped area of hypodensity in a vascular distribution classic o Hypodensity increases with age of infarct • Acute: Subtle hypodensity • Subacute: t Hypodensity & edema • Chronic: Gliosis/encephalomalacia with volume loss typical o Cerebral hemispheres> posterior fossa o Often in a single vascular distribution o May appear as multiple lesions if embolic • Trauma o DAI & cerebral contusions typically hemorrhagic (hyperdense)

o Trauma history is usually known • Cerebral Contusion o Brain surface injuries involving superficial gray matter (GM) & contiguous subcortical white matter (WM) o Classic location: Anterior inferior frontal lobes & inferior temporal lobes o Hemorrhagic> nonhemorrhagic o Soft tissue injury in 70% of patients • Diffuse Axonal Injury (DAI) o Punctate hemorrhages at corticomedullary junction, corpus callosum, deep GM, & upper brainstem classic oCT often normal acutely (50-80%) o May see small hypodense edematous foci o Petechial hemorrhage in up to 50% • Metastases, Parenchymal o Multifocal enhancing lesions with edema at corticomedullary junctions Helpful Clues for Less Common Diagnoses • Multiple Sclerosis o Multiple hypodense periventricular lesions o Variable enhancement o Young adult presentation common • Infection o Pattern of brain involvement may help differentiate various etiologies o Fungal & parasitic infections less common • Encephalitis (Miscellaneous) o Viral agents most common o Many involve deep gray nuclei o Hypodense lesions with patchy enhancement common o Herpes encephalitis most common agent • Predilection for limbic system • Involves cortex and subcortical WM • Bilateral, asymmetric involvement • Abscesses o Four pathologic stages: Early cerebritis, late cerebritis, early capsule, late capsule o Imaging varies with abscess stage o Bacterial> > fungal/parasitic o Multiple often related to septic emboli o Frontal, parietal lobes commonly involved • Opportunistic Infection, AIDS o Toxoplasmosis: Multiple ring-enhancing lesions of varying size with surrounding edema in deep & superficial brain o PML: Large multifocal subcortical WM lesions without mass effect, enhancement

MULTIPLE

HYPODENSE

PARENCHYMAL

en

LESIONS

'"

r::

TB & fungal: Solid, mildly hyperdense or hypodense masses Tuberculosis o Basilar meningitis + parenchymal lesions highly suggestive o Tuberculomas: Hypodense parenchymal masses with solid or ring enhancement o Meningitis is most frequent manifestation of CNS TB & is more common in children ADEM o Multifocal WM &/or basal ganglia (BG) lesions after infection or vaccination o Hypodense flocculent, asymmetric lesions o Initial CT normal in 40% Acute Hypertensive Encephalopathy, PRES o Patchy cortical/subcortical PCA territory lesions in a hypertensive patient o Posterior parietal, occipital lobes > BG, posterior fossa o Usually bilateral, often asymmetric Vasculitis o Characterized by non-atheromatous inflammation & blood vessel wall necrosis o May see multifocallow density areas in subcortical WM, BG o Initial CT often normal; angiography remains gold standard o

•

•

•

•

Helpful Clues for Rare Diagnoses • Glioblastoma Multiforme o Single hypodense mass with central necrosis & rim enhancement common o Multifocal or multicentric disease rare

• Osmotic Demyelination Syndrome o Acute demyelination caused by rapid shifts in serum osmolality o 50% in pons (CPM): Central fibers involved; peripheral fibers spared o 50% extra-pontine sites (EPM): BG, WM • Tuberous Sclerosis Complex o Cortical/subcortical tubers, WM lesions o Frontal> parietal> occipital> temporal o Calcified subependymal nodules typical • Lyme Disease o Small hypodense periventricular lesions o Cranial nerve enhancement common • Systemic Lupus Erythematosus o Small multifocal hypodense WM lesions o Focal infarcts of various sizes; symptomatic "migratory" edematous areas o Frontal, parietal subcortical WM common • CADASIL o Characteristic subcortical lacunar infarcts & leukoencephalopathy in a young adult o Anterior temporal pole & external capsule lesions (high sensitivity & specificity) o Subcortical hypodense lesions typical, may be confluent • Rickettsial Diseases o Rocky Mountain spotted fever most common (skin rash) o III-defined areas of WM & GM hypodensity ± petechial hemorrhage o Variable enhancement • Lymphoma, Intravascular (Angiocentric) o Multifocal WM lesions + enhancement o May mimic chronic small vessel ischemia

Cerebral

Axial

NECT

hypodensities

shows

muldple

wedge-shaped

= related to chronic ischemia in this

multi-infarct dementia patient. The multiple distributions suggest a central embolic source.

vascular

-=

::J

0-

lD ., Ql

::J

....

lD Q)

:::J

-u Q) ...• CD

:::J () ::T '<

3

Q)

Contusion

Axial NECT shows hemorrhagic

contusions

Ql

& nonhemorrhagic

related to deceleration injury from a

mOlOr vehicle crash. NOle involvement of the fronlal & lemporallobes, classic locadon.

I 5 61

MULTIPLE HYPODENSE

cu ~

PARENCHYMAL

LESIONS

Q)

c Q)

c..? cu E >-

J::: <..l

C

~ cu Q)

a..

c

~ co c: I'll

~

CO

"c: I'll

Diffuse

Axonal Injury

(DAI)

Metastases,

Parenchymal

(Left) Axial NECT shows hemorrhagic & non hemorrhagic ~ foci of OAI in typical locations, most commonly at the gray-white interfaces. CRE/SWI MR often shows additional lesions. (Right) Axial NECT shows multiple hypodense lesions related to lung cancer metastases in this palient with altered mental status. Parenchymal metastases enhance after contrast & typically have significant surrounding vasogenic

=

=

edema.

Encephalitis

(Miscellaneous)

Abscesses

(Left) Axial NECT shows hypodensity in the temporal lobes bilaterally & inferior right frontal lobe related to herpes encephalitis. Cortex & subcortical white

a

matter involvement is typical. Associated hemorrhage is common. (Right) Axial NECT shows multiple parietal lobe hypodensities related to multiple abscesses. The frontal & parietal lobes are

=

most commonly involved. MR shows OWl restriction centrally.

Opportunistic (Left) Axial CECT shows multiple

ring-enhancing

lesions with surrounding hypodensity in this If/V patient with toxoplasmosis. Toxoplasmosis is the most

common opportunistic infection in the CNS. (Right) Axial NECT shows multiple hypodensilies in both hemispheres related to a combination

of edema

surrounding T8 granulomas ~ & infarcts secondary to T8 meningitis

=.

I 5 62

Infection,

AIDS

Tuberculosis

MULTIPLE

HYPODENSE

PARENCHYMAL

,...

Ul

lESIONS

c:

III

::l

Co

Acute Hypertensive

CD ..,

Encephalopathy,

III

PRES (Left) Axial NECT shows hypodensity in the deep gmy nuclei I:] & perivenlricular while maller

E1 in

this

young patient with acute symptoms after a recent viral illness. /nvolvement of white maller & deep gray structures ;5 common in ADEM. (RighI) Axial NECT shows hypodense lesions I:] in the parieta/lobes bilaterally in this hypertensive patient, typical of PRES.PRESis commonly OWl negative & reversible.

::l OJ .., OJ

::l -0

.., OJ

C1>

::l ()

or

'<

3

OJ

G) C1>

::l C1> .., Ol

(Left) Axial NECT shows multiple infarcts in this patient with angioinvasive fungal vasculitis related to aspergillosis. Multiple low density lesions in the subcortical white matter & deep gray nuclei is common. OWl MR may be positive acutely. (Right) Axial N[CT shows multiple parenchymal hypodensities I:] in the cortex & subcortical white

maller related to tubers. Note the multiple calcified subependymal nodules, characteristic of tuberous sclerosis complex.

Rickettsial Diseases (Left) Axial NECT shows multiple hypodense lesions in the while maller related to hypertensive encephalopathy secondary to severe renal involvement in this patient with lupus. (Right) Axial CECT shows low density in the deep gray nuclei bilaterally, with areas of petechial hemorrhage 1:]. White maller hypodensity is also seen. Rickettsial diseases often a((ect the basal ganglia & show small infarct-like lesions in both the deep gray & white matter.

I 5 63

MULTIPLE BRAIN HYPERINTENSITIES

ell

~

(T2/FLAIR),

COMMON

Q)

c Q)

t?

Common • Aging Brain, Normal • ormal Myelination • Reactive Astrocytosis (Gliosis) & Encephalomalacia • Atherosclerosis, Intracranial • Neurofibromatosis Type 1 o Myelin Vacuolization • Enlarged Perivascular Spaces o Mucopolysaccharidoses • Lacunar Infarction • Chronic Hypertensive Encephalopathy • Acute Hypertensive Encephalopathy, PRES • Cerebral Infarct, Subacute • Cerebral Infarct, Chronic • Hypotensive Cerebral Infarct • Cerebral Edema, Traumatic • Cerebral Contusion • Diffuse Axonal Injury (DAI) • Multiple Sclerosis • Metastases, Parenchymal • Lymphoma, Primary CNS • Radiation and Chemotherapy • Periventricular Leukomalacia

ESSENTIAL INFORMATION

I 5 64

Helpful Clues for Common Diagnoses • Aging Brain, Normal o White matter (WM) hyperintensities are normally seen • Rule of thumb: 1 per decade to age SO o Increase in number & size is exponential from age SO to 100 years o Due to gliosis, leukoariosis, & enlarged perivascular spaces (PVS) • Normal Myelination o T2 hyperintense myelin at birth, except posterior fossa, optic radiations, & corticospinal tracts o Corpus callosum (CC) myelinates from 4 to 9 months, splenium to genu o Parietal & frontal myelination from center to periphery until around 2 years of age • Reactive Astrocytosis (Gliosis) & Encephalomalacia o Brain's only response to insults: Infectious, stroke, trauma o

Gliosis is T2 hyperintense without mass effect, encephalomalacia

often associated

Encephalomalacia is a "hole" that follows CSF signal, often surrounded by gliosis Atherosclerosis, Intracranial o Results in distal emboli or hypoperfusion infarcts o Variable infarct location, depends upon vessel involved Neurofibromatosis Type 1 o Nonenhancing T2 hyperintensities in basal ganglia (BG) & deep cerebellum most commonly (myelin vacuolization) o No mass effect, unlike astrocytoma, the main differential in NFl o Develops in early childhood, peaks around age 8, & usually regresses by late teens Enlarged Perivascular Spaces o Commonly symmetric & peripheral in WM, but can be unilateral focal & deep o Inferior BG, near anterior commissure common location o Sharp margins & lentiform, follows CSF on T2/FLAlR in young patients o Often associated with gliosis in the elderly (FLAIRhyperintense) o MucopoIysaccharidoses • Dilated PVS usually with surrounding gliosis presenting in infancy • CC & peri atrial WM most common Lacunar Infarction o Usually in lenticular & caudate nuclei, thalamus, internal capsules, periventricular o

DIFFERENTIAL DIAGNOSIS •

•

•

•

WM

Acute: T2 hyperintense, diffusion positive o Chronic: Focal encephalomalacia with surrounding gliosis • Chronic Hyperintensive Encephalopathy o Usually deep & periventricular WM confluent hyperintensities o Often associated with T2 hypointensities from microhemorrhage on GRE images • Acute Hypertensive Encephalopathy, PRES o Peripheral subcortical confluent hyperintensities, mild mass effect o Bilateral occipital parietal is common, but many variations including hemorrhage • Cerebral Infarct, Subacute o Embolic infarcts usually cortical, wedge-shaped with mass effect o Microembolic infarcts are usually peripheral centrum semiovale or BG o

MULTIPLE

BRAIN HYPERINTENSITIES

Enhancement typical Cerebral Infarct, Chronic o Results in focal encephalomalacia & gliosis o Typically in a major vascular distribution Hypotensive Cerebral Infarct o Watershed infarcts • Parasaggitallinear "string of pearls" in the centrum semiovale • Wedge-shaped regions in the border zone between vascular distributions o Diffuse or multifocal cortical infarcts & BG o Diffusion positive acutely Cerebral Edema, Traumatic o Cerebral swelling without T2 change early, may develop hyperintensities o Contusion & DAI commonly with hemorrhage Cerebral Contusion o Cortical, subcortical hyperintensities with developing hemorrhage o Regions of injury: Temporal, frontal lobe, superficial brain with direct trauma Diffuse Axonal Injury (DAI) o Shear stress deceleration injury: Gray-white, midbrain hemorrhage; diffusion positive early o Typically in older children to young adults, as there is minimal subarachnoid space & brain movement Multiple Sclerosis o CC & peri 4th ventricular involvement characteristic o Radiating periventricular location, "Dawson fingers"

•

•

•

•

•

COMMON

Acute tumefactive lesion: Large with T2 hypointense ring that enhances, usually little mass effect Metastases, Parenchymal o Hyperintensities may be punctate to massive, with variable surrounding edema, mass effect o Hyperintensity, edema, & mass effect less prominent in posterior fossa, but risks higher Lymphoma, Primary CNS o Central region nearly T2 isointense due to high nuclear to cytoplasmic ratio o Surrounding edema variable, usually crossing or around CC in immunocompetent o Immunocompromised PCNSL will have multifocal ring-like "glioblastoma" look Radiation and Chemotherapy o Radiation leukomalacia: Confluent poorly marginated regions in the radiation field without enhancement o Radiation necrosis: Irregular ring-enhancing lesions with variable mass effect, may grow, CBV/choline low Peri ventricular Leukomalacia o WM volume loss, gliosis, & focal cystic lesion in the periatrial WM o Associated with prematurity o

o

•

(T2/FLAIR),

•

•

•

•

III

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a.

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Aging Brain, Normal

Axial FLAIR MR shows minimal deep while maIler hyperintensilies I:'.] & minimal gyral atrophy in this healthy 76 year old patient. These hyperinlensilies may be seen as parI of the aging process.

Axial FLAIR MR shows more extensive & confluent regions of hyperintensity including perivascular "leukoariosis" in this 96 year old healthy individual. Note the minimal atrophy.

I 5 65

MUlTIPLE

ro ~

BRAIN HYPERINTENSITIES

(T2/FlAIR),

COMMON

Q)

c Q) (9

ro

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ell

Normal

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normal

III

the centrum semiovale

•...

myelination

Normal

Myelination

within

=

ell

emanating

"'C C

capsules. (Right) Axial T2WI MR at 12 months of age shows normal residual hyperintense signal in the juxta cortical white maller of the frontal lobe & insula and in the peripheral white maller of the parietal lobes

III

Myelination

(Left) Axial T2WI MR shows a normal myelin pattern at 5 months of age. There;s hyperintensity throughout the frontal & parietal white maller & hypointellsity of

from the internal

=

81.

Reactive Astrocytosis (Gliosis) & Encephalomalacia

Reactive Astrocytosis (Gliosis) & Encephalomalacia

(Left) Axial FLAIR MR shows profound asymmetric perivenlricufar

while matter

volume loss & hyperintensity indicative of gliosis l:ll along with generalized left greater than right atrophy ill this microcephalic 14 year old. (Right) Axial T2WI MR

shows volume loss with enlarged subarachnoid, sylvian, & ventricular CST spaces @ CSF isointense cystic encephalomalacia Ii8 & mixed intensity gliolic brain in this patient with chronic hemispheric infarction.

Atherosclerosis, (Left) Axial T2WI MR shows parasaggital deep white maller hyperintensities in the right hemisphere, almost Forming a distinct line due to low-flow infarcts along watershed 7ones. This patient had an ICA occlusion with inadequate coJlalerals. (Right) Axial FLAIR MR shows multiple foci of parenchymal hyperintensities in the globus pallidi and

=

subinsular

= =-

while maller

characteristic of myelin vacuolization of NF I.

I 5 66

Intracranial

Neurofibromatosis

Type 1

MULTIPLE BRAIN HYPERINTENSITIES

(T2/FlAIR),

,.. r::

COMMON

(JI

III

::::l

0-

ro ., Myelin Vacuolization

Enlarged Perivascular Spaces

III

(Left) Axial FLAIR MR shows numerous

increased signal intensity in Ihe midbrain & lemporal lobe =:I due 10 myelin vacuolization,

common

in

Ihe BG & deep cerebellum. These are Iransienl & usually resolve in lale childhood. They have variable margins & rarely enhance. (RighI) Axial T2WI MR shows mulliple sharply demarcaled enlarged PVS =:I wilh a characteristic appearancel being sharply marginaled & oval, allhough markedly asymmetric.

Mucopolysaccharidoses

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focal areas of

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Mucopolysaccharidoses (Left) Axial T2WI MR shows enlarged PVS in the periatrial WM eXlending into posterolateral margin of lhe ee splenium 1J:2. These have a typical radialing, linear, eSF-isoimense appearance. (RighI) Axial (LAIR MR shows diffuse hyperintensily of the deep WM due CO gliosis & mullifocal eSF-intensily enlarged PVS filled wilh unmelabolized mucopolysaccharide. The degree of callosal & seplal involvement is rarely seen in olher forms of PVS

=

enlargement

Lacunar Infarction (Left) Axial T2WI MR shows very sublle increased signal in an acute lacunar infarct =:I (OWl posilive). A more well-defined chronic lacunar infarct ~

& chronic

while

matter disease are also seen. (Right) Axial FLAIR MR

shows hyperintensities in the periventricular while malle' with areas of chronic

=

hyperlensive hemorrhage IJ:2 in the putamina. GRE/SWI MR (not shown) often demonstrates additional hemorrhagic foci.

I 5 67

MUlTIPLE

ro

Acute Hypertensive Encephalopathy, PRES

E

>-

.!: (J

C Q)

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0..

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C nl

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BRAIN HYPERINTENSITIES

(T2/FLAIR),

COMMON

Cerebral

Infarct, Subacute

(Left) Axial FLAIR MR shows marked juxtacorUcal while matter hyperintensity =:II & modest gray matter hyperintensity & thickening typical for acute hypertensive encephalopathy. (RighI) Axial T2WI MR shows subacute cerebral infarction involving the middle cerebral &. anterior cerebral artery ~ vascular distributions with hyperintensity & gyral swelling and sulcal

= =

effacement.

The while matter

is less hyperintense than that seen in PRES.

(Leh) Axial fLAIR MR shows a chronic middle cerebral artery infarct with surrounding hyperintensilies due to gliosis & central CSF intensity due to encephalomalacia IJ:J. (Right) Axial FLAIR MR shows hyperintensilies in a

=

=-

linear "string of beads"

parasaggital WM corresponds to the

in the

which

watershed zone between basal perforating arteries & penetrating cortical vessels. The small central hypointense areas are due to encephalomalacia.

Diffuse Axonal Injury (DAI) (Left) Axial T2WI MR shows hyperintensilies in the medial peripheral frontal lobes at the gray-white matter junction, typical for OAI A small contusion I!:e is also

=.

seen. Associated hemorrhagic

foci are beller

seen with CRE/SWI. (Right) Axial FLAIR MR shows a large hyperintense lesion with a marked hyperintense rim with lesions in the corpus callosum & frontal lobe typical for a large acute demyelinating plaque

=

=

I 5 68

with smaller more chronic

lesions.

Multiple Sclerosis

MULTIPLE BRAIN HYPERINTENSITIES

(T2/FLAIR),

en

COMMON

~ c:

Multiple Sclerosis

Metastases,

Parenchymal (Left) Sagittal FLAIR MR shows numerous hype,intense plaques involving the juxtacortical deep, & peri ventricular white matter. The marked callosal involvement & perpendicular orientation at the callososeptal interface ~ are highly specific for MS. (RighI) Axial FLAIR MR shows multiple hemispheric hyperinlensiUes with central isoinlense masses ~ typical for parenchymal metastases. The prominent edema is also

=-

suggestive

G) CD :J

, CD OJ

of metastatic

disease.

Metastases, Parenchymal (Left) Axial T2WI MR shows scattered foci of T2 hyperintensity in the central while matter II}] that enhanced with gadolinium in this patient with metastatic breast cancer. This "miliary" pattern is more commonly seen with small cell lung, thyroid, and melanoma. (Right) Axial FLAIR MR shows hyperintense perivenlricuJar lesions m. The mixed intensity of the splenial callosal lesion PJ::I is due to a high nuclear to cytoplasmic

ratio within

the

tumor.

(Left) Axial T2WI MR shows periventricufar

while maller

& centrum semiovale

hyperintensWes with sparing of the subcortical U-fibers due to treatment-related leukoencephalopathy. (Right) Axial FLAIR MR shows enlargement of the

=

lateral ventricular trigones & periventricular hyperintensities due to gliosis PJ::l in this young adult who was born prematurely. Pedalrial white matler volume loss, gliosis, & macrocystic change in a premie are characteristic.

I 5 69

ro L

MULTIPLE

BRAIN HYPERINTENSITIES

(T2/FlAIR),

LESS COMMON

Q)

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Less Common • Cerebral Amyloid Disease • ADEM • Vasculitis • Sickle Cell Disease • Leigh Syndrome • Thrombosis, Cortical or Deep Venous • CMV, Acquired • CMV, Congenital • Cerebritis • Encephalitis (Miscellaneous) • Herpes Encephalitis • Septic Emboli • Neurocysticercosis (NCC) • Parasites, Miscellaneous ·PML • Opportunistic Infection, AIDS • Glioblastoma Multiforme • Gliomatosis Cerebri • Osmotic Demyelination Syndrome • CO Poisoning • Drug Toxicity, NOS • Tuberous Sclerosis Complex • Susac Syndrome

•

•

•

•

ESSENTIAL INFORMATION

I 5 70

Helpful Clues for Less Common Diagnoses • Cerebral Amyloid Disease o Multifocal juxtacortical small infarcts & hemorrhages of varying ages o Little to no deep white matter (WM) or basal ganglia (BG) involvement o Acute lobar hemorrhage, the usual presenting symptom, typically large o May see confluent WM hyperintensity • ADEM o Multifocal WM lesions, punctate to flocculent, with enhancement, faint & fuzzy early, ring-like later o May mimic MS, but lesions are often more peripheral WM & all at same stage o Usually 10-14 days following infection or vaccination • Vasculitis o Multiple hyperintensities typical; pial & subarachnoid hemorrhage common o Less cortical involvement & more enhancement than embolic stroke

Granulomatous (PACNS), drug-induced, & infectious vasculitis usually moderate-sized vessels: M1 to cortical surface, may involve basal structures o Lupus & radiation-induced vasculitis are small vessel & usually angiographically occult with punctate to confluent hyperintensi ties Sickle Cell Disease o Creates a moyamoya pattern of vascular stenosis & occlusion with infarcts in MCA territory or watershed o Demographic & family history differentiate it from classic moyamoya Leigh Syndrome o Symmetric hyperintensity in regions of oxidative activity o Putamina & periaqueductal gray> caudate > globi pallidi, brains tern, thalami, dentate Thrombosis, Cortical or Deep Venous o T2 hyperintensity without diffusion restriction unless infarction has developed o Lesions usually solitary when isolated cortical venous o Dural sinus: Multiple lesions o Deep venous: Bilateral thalamic CMV, Acquired o Opportunistic infection with periventricular (4th> lateral) & cerebellar > cortical hyperintensity with mild enhancement CMV, Congenital o Multifocal deep band-like T2 hyperintensity with microcephaly & calcifications o Cortical dysplasia, agyria, myelination delay, periventricular cysts Cerebritis o Early stage of bacterial infection, prior to cavitation & enhancement seen in abscess o Peripheral, poorly marginated large lesion with mass effect Encephalitis (Miscellaneous) o Most non-herpes encephalitides involve the BG, thalamus, midbrain, & WM o Variable enhancement Herpes Encephalitis o Cortical & subcortical WM with bilateral, asymmetric involvement of the medial temporal & inferior frontal lobes & insula o Pial-cortical enhancement; OWl positive o

DIFFERENTIAL DIAGNOSIS

•

•

•

•

MULTIPLE

BRAIN HYPERINTENSITIES

(T2/FLAIR),

LESS COMMON

en

" r::

• Septic Emboli o Scattered small juxtacortical hyperin tensi ties o Develop into small ring-enhancing micro-abscesses • Neurocysticercosis (NCC) o Vesicular phase: Small 10 mm cysts with central dot- or comma-shaped scolex, no edema, follows CSF o Colloidal phase: Cyst may enlarge, is hyperintense to CSF,+ surrounding edema, enhancement o Granular nodular & calcified phase: Cyst retracts, wall thickens, edema resolves, calcifies • Parasites, Miscellaneous o Cystic mass or masses with hypointense rim & surrounding edema o Many with hemorrhage, which is uncommon in bacterial infection

•

•

•

•

·PML Multifocallarge WM lesions that lack mass effect, rarely enhance o Involves subcortical U-fibers • Opportunistic Infection, AIDS o Toxoplasmosis: Peripheral ring-enhancing "abscesses" o Cryptococcus: Enlarged perivascular spaces o CMV: Subtle ventriculitis, pial inflammation o Tuberculosis: Meningitis, tuberculous abscesses • Glioblastoma Multiforme o Rarely multifocal or multicentric

Heterogeneous mass with irregular enhancement o May cross the corpus callosum Gliomatosis Cerebri o Extensive multilobar or diffuse cerebral hyperintensity with mild mass effect o Preservation of underlying architecture Osmotic Demyelination Syndrome o Central pontine hyperintensity sparing the periphery & cortical spinal tract, round or trident-shaped (CPM) o BG & WM lesions with extra-pontine myelinolysis (EPM) CO Poisoning o Bilateral globi pallidi hyperintensity ± adjacent hemorrhage o May see putamen, caudate, & WM hyperintensity Drug Toxicity, NOS o WM multifocal strokes: Cocaine, amphetamine o Diffuse leukoencephalopathy: Inhaled heroin Tuberous Sclerosis Complex o Cortical tubers: juxtacortical hyperintensities o Calcified subependymal nodules Susac Syndrome o Callosal involvement always; central rather than at callosal septal margin seen in MS o Will leave "holes" in central callosum in chronic cases o Involves BG in 70%, much more than MS o

o

•

•

III

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ro::J ()

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I Axial FLAIR MR shows patchy & confluent T2 hype,intensities 1:2 in the deep and subcortical white matter bilaterally. The lesion distribution is often more peripheral than in arteriolosclerosis.

Axial FLAIR MR shows numerous peripheral hyperintensities generally sparing the cortex & extending around the subcortical U-fibers typical for AD[M.

=-

Bilateral, asymmetric involvement is common.

5 71

MULTIPLE BRAIN HYPERINTENSITIES

(T2/FLAIR),

LESSCOMMON

(Lefl) Axial FLAIR MR shows confluent

while maller

hyperinlensity primarily affecling the fronlal lobes with a small amounl of old hemorrhage in the right hemisphere due to granulomatous angiitis. (Right) Axial PO FSEMR shows bilateral subfrontal infarctions with increased

=-

-=

flow voids in paramedian

sulci ~

due to pial collateral

engorgement in this African American child. The Findings

are similar to moyamoya differenl demographic.

in a

Thrombosis, (Left) Axial T2WI MR shows bilaleral putaminal hyperintensity & swelling classic for acute Leigh syndrome with periatrial signal abnormality~. (Right) Axial T2WI MR shows hyperinlensity & swelling in the lhalami, putamina, & caudate heads bilaterally with hypointensity of the internal cerebral & thalamOSlriate

=

=

veins due to deep venous thrombosis.

(Left) Coronal FLAIR MR shows thin regular linear hyperintensities in the immediate

perivenlricular

while maller & caudate rim of the lateral & 3rd ventricles typical for

=

acquired

=

CMV

ventriculitis

in

this AIDS patient. (RighI) Axial T2WI MR shows extensive periventricular hyperintensity with germinal matrix cysts ~ & perisylvian cortical dysplasia ~. Microcephaly &

=

calcifications

I 5 72

are also

common in congenital CMV.

Cortical

or Deep Venous

MUlTIPLE

BRAIN HYPERINTENSITIES

(T2/FLAIR),

,.-c:

LESS COMMON

CIl

Dl

:l Q.

l:D ....• Dl

Cerebritis (Left) Axial T2WI MR shows abnormal hyperintense signal in the cerebellar hemispheres ~ due to cerebellitis. Enhanced images showed

marked enhancement. Cerebellitis is often a disease of children & is typically bilateral. (Right) Axial FU\IR MR shows symmetric hyperintense signal within the thalami with involvement of the deep WM E!lI in this EBVencephalitis patient. Viral encephalitis typically involves the BG, thalami, cortex, &/o{

=

:l OJ ....• OJ :l

-U OJ ....• CD :l ()

::r

'< 3 OJ

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brainstem.

(Left) Axial FU\IR MR shows symmetric hyperinlensily in the medial temporal lobes & hippocampi bilaterally Sparing of the basal ganglia & brainstem is typical of herpcs enccphalitis. (RighI) Axial T2WI MR shows the typical appearance of a small brain abscess with a

=.

=-

hypointense rim central necrosis, & modest surrounding edema, occurring in a patient with streptococcal endocarditis with an associated cervical

cord abscess.

Neurocysticercosis

(NCC)

Parasites, Miscellaneous (Left) Sagittal T2WI MR shows numerous CSF isoinlense cysts with a

discrete, eccentric,

=

hypoinlense scolex in each & lack of edema, due to disseminated or "miliary" form of NCe. (Right) Axial FU\IR MR shows mixed hypo-/hyperintense right frontal mass with multiple smaller supratentorial masses

=

due

to

amoebiasis.

Hypoinlense hemorrhage or calcification, common in parasitic infections, is atypical for other infections.

I 5 73

MULTIPLE BRAIN HYPERINTENSITIES

~

(T2/FLAIR),

LESSCOMMON

Q)

c Q)

CJ

ro

E

>.

.r:

()

c

~ Q)

ro n.. c

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III

c ell

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CO 't:l C

ell

(Left) Axial T2WI FS MR shows confluent, high signal in the fronlallobes wilhout significant mass effect. The subcorlical U-fiber involvement leads to a "scalloped" appearance to the gray-white junction (;8 (Right) Axial FLAIR MR shows numerous mixed hyperintense lesions commonly seen with

m

toxoplasmosis, the most opportunistic eNS infection in AIDS. Ring enhancement is a/so typical. common

(Left) Axial T2WI MR shows mu/tifocal high signa/lesions in the BG midbrain E!:l & subcortical WM characteristic of gelatinous "pseudocysts" caused by

= =

cryptococcosis

due to

dilated PVS filled with fungi, mucoid material, & infiammalOry cells. (Right) Axial FLAIR MR shows extensive hyperintensity infiltrating the cerebral WM & corpus callosum 1::1 wilh mass effect due 10 atypical GBM.

Gliomatosis (Left) Axial T2W/ MR shows mullifocal hyperinlensily infiltrating Ihe thalamus, basal ganglia, insula, & fronla/lobe while & gray matter with mild associated enlargement

of the involved

structures, typical for gliomatosis cerebri. Involvement

of more than

one lobe is common. (Right) Axial T2WI MR shows high signal intensity in the pons with characteristic symmetric geographic pal/ern typical for centra! pontine myelinolysis (CPM).

=

I 5 74

Cerebri

Osmotic

Demyelination

Syndrome

MULTIPLE BRAIN HYPERINTENSITIES

(T2/FLAIR),

LESSCOMMON III

:J

0-

III .,

Osmotic

Demyelination

Syndrome

III

CO Poisoning (Left) Axial FLAIR MR shows hyperintensity in the bilateral putamina E:II and caudate nuclei !:l'l due to osmotic demyelination, extra-pontine. Central and extra-pontine myelinolysis are often seen in the same patient. (Right) Axial T2WI MR shows hyperintensity 8. decreased size of the globus pallidi =.1 surrounded by a hypointense rim Sltypical for chronic carbon monoxide poisoning.

:J OJ

03 :J

-U OJ

CD

:J ()

::r

'< 3 OJ

G) CD :J CD ., OJ

Tuberous Sclerosis Complex (Left) Axial T2WI MR shows multiple hyperintense foci involving the basal ganglia 8. cerebral white maUer !:l'l caused by amphetamine-induced vasculitis. (Right) Axial T2WI MR shows multiple subcortical hyperinlensilies =.1 due to peripheral tubers. The hypointense subependymal nodules!:l'l 8. heterogeneous giant celt astrocytoma at the foramen of Monro E:II are diagnostic of tuberous sclerosis.

=.1

Tuberous Sclerosis Complex

Susac Syndrome (Left) Axial T2WI MR shows normal

immature

myelin in

this infant with subtle premature hypointensity in a tuber of the medial left frontal white maUer along with multiple low signal intensity subependymal nodules 81. (Right) Axial FLAIR MR shows hyperintensities in the

=-

white maller

=-

involvement

with

of the corpus

callosum always associated with Susac syndrome. Imaging often mimics multiple sclerosis.

I 5 75

ro ~

MUlTIPLE

BRAIN HYPERINTENSITIES

(T2/FLAIR),

RARE BUT IMPORTANT

QJ

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Rare but Important • CADASIL • Neurosarcoid • Hashimoto Encephalopathy • Granulomatous Angiitis • Lyme Disease • West Nile Encephalitis • Wegener Granulomatosis, Brain • Paraneoplastic Syndromes • Lymphoma, Intravascular (Angiocentric) • Olivopontocerebellar Degeneration • Subacute Sclerosing Panencephalitis • Rasmussen Encephalitis • Kernicterus

•

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Lesion location is critical: Gray vs. white matter (WM), basal ganglia (BG) vs. periphery, or specific locations • Treatment in these diagnoses is often specific & consideration of these rare diagnoses is important • Enhancement helps separate inflammatory from noninflammatory lesions

I 5 76

Helpful Clues for Rare Diagnoses • CADASIL o Subcortical bilateral anterior temporal poles involved early o Diagnosis age 20-40 years is common, unique to CADASIL o External capsule involvement somewhat specific, but other WM regions, thalamus, BG, pons also commonly involved o Frontal lobe predominant involvement developing into confluent lesions will become more prominent after age 50 o Migraine-like symptoms common, but CADASILlesions larger than typical punctate lesions in migraineurs o Can have a multiple sclerosis-like appearance early in the disease, although callosal involvement is rare • Neurosarcoid o Pial & leptomeningeal involvement with extension via perivascular spaces o Peripheral WM hyperintensities, intense enhancement

Parenchymal lesions can extend to the periventricular WM; usually confluent o Associated T2 hypointensity in dura & leptomeninges is characteristic, but can be seen with secondary lymphoma & metastasis Hashimoto Encephalopathy o MR positive in 25%, involves hippocampus, WM, cerebellum o Lesions usually ill-defined, no enhancement o May mimic olivopontocerebellar degeneration (OPCD) Granulomatous Angiitis o Multiple subcortical & cortical infarcts, often with peripheral subarachnoid hemorrhage o Peripheral segmental symmetric stenoses typical, not seen in CADASILor chronic hypertensive disease Lyme Disease o Scattered lesions 2-3 mm typical, usually less than 10 mm o May be DWI + & may enhance o Cortical involvement unusual o Myalgia, arthralgias, petechial rash of the palms & soles suggest Lyme disease West Nile Encephalitis o Midbrain, substantia nigra, cerebellum, & anterior horn of the spinal cord involvement typical o Moderate-sized lesions, ill-defined, leptomeningeal enhancement Wegener Granulomatosis, Brain o Similar to neurosarcoid in distribution, T2 signal, & enhancement o Necrotizing vasculitis with paranasal sinus & orbital involvement Para neoplastic Syndromes o Limbic encephalitis: Hyperintensity in amygdala, hippocampus, cingulate gyrus, & inferior frontal lobe WM o Paraneoplastic cerebellar degeneration: Bilateral peripheral cerebellar & pontine involvement o Mild edema in the acute phase; atrophy in the chronic phase Lymphoma, Intravascular (Angiocentric) o Multifocal, often confluent periventricular hyperintensity o

DIFFERENTIAL DIAGNOSIS

•

•

•

•

•

MULTIPLE

BRAIN HYPERINTENSITIES

(T2/FlAIR),

RARE BUT IMPORTANT

en ,... c:

Radiating enhancement pattern along deep medullary veins Olivopontocerebellar Degeneration a Cruciate T2 hyperintensity in lower pons a Cerebellar hemispheres more involved than vermis, with "fine comb" cerebellar folia in dominant form a Lateral cerebellar hemisphere atrophy with "fish mouth" deformity in recessive form Subacute Sclerosing Panencephalitis a Multifocal large or diffuse T2 hyperintensity extending into the gyri with callosal involvement; no enhancement a Similar features to progressive multifocal leukoencephalopathy with differing past medical history a Diffuse atrophy with severe WM volume loss late a Presents in childhood or early adolescence Rasmussen Encephalitis a Early focal cortical swelling & gray-white differentiation loss, usually does not enhance o Atrophy of the cerebral hemisphere or a lobe late a Begins in childhood, progressive seizures, hemiparesis, cognitive deterioration Kernicterus o Globus pallidus, hippocampi, substantial nigra & dentate nuclei, T2 & T1 hyperintensity o Encephalopathy due to deposition of unconjugated bilirubin a

•

•

•

•

III

Alternative Differential Approaches

• Characterize lesions by enhancement a Enhancing multiple rare T2 lesions • Neurosarcoid • Wegener granulomatosis • Granulomatous angiitis • Lymphoma, intravascular a Nonenhancing multiple rare T2 lesions • CADASIL • Hashimoto encephalopathy • Lyme disease • West Nile encephalitis • Paraneoplastic syndromes • Olivopontocerebellar degeneration (OPCD) • Subacute sclerosing panencephalitis • Rasmussen encephalitis • Kernicterus • Characterize lesions by location a Anterior temporal lobe: CADASIL,trauma o Limbic system/cerebellum: Paraneoplastic syndromes, herpes a Olive, pons, cerebellum: OPCD, multisystem atrophy a Unilateral hemisphere: Rasmussen encephalitis, Sturge-Weber, Dyke-Davidoff-Mason o Deep white matter: Granulomatous angiitis, intravascular lymphoma, Hashimoto, multiple sclerosis, arteriolosclerosis a Basal ganglia: Kernicterus, hypoxia, West Nile, Leigh, Wilson

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CADASIL

I

=

Axial FLAIR MR shows hyperintensity in the subcorUcal white matter of the anterior temporal lobes typical of CAOASft along with periventricular lesions in this 32 year old woman.

Axial T2WI F5 MR shows extensive confluent frontal white matter hyperintensity in this 57 year old woman. The extensive, confluent involvement is atypical for chronic hypertensive change or MS.

5 77

MUlTIPLE

BRAIN

HYPERINTENSITIES

(T2/FlAIR),

RARE BUT IMPORTANT

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Neurosarcoid

Neurosarcoid

(Left) Axial FLAIR MR shows unusual signal abnormality along the corpus callosum caudate nucleus, a thickened septum pellucidum & bilateral parieto-temporal white mailer. (Right) Coronal T1 C+ MR shows enlargement of the choroid plexus I:] & enhancement in the cerebellum. The left convexity lesion has typical pial-leptomeningeal enhancement with extension into the parenchyma ~ via

m

=-

perivascular spaces.

Granulomatous

Angiitis

(Left) Axial T2WI MR shows multiple confluent hyperintensities in the frontal & parietal white matter that extend into the gyri but spare the immediate juxtacortical white maller

=

related

to

Ilashimoto encephalopathy (Rigl1t) Axial T2WI MR show confluent

while matter

hyperintensity primarily affecting the (rontallobes with smaller regions on the right posteriorly. Old hemorrhage in the right hemisphere I:] suggests vasculitis.

Lyme Disease (Left) Axial fLAIR MR shows small white maller

I 5 78

hyperintensity in the deep, peripheral, & juxtacortical white malter. The scattered peripheral nature with small foci is typical for Lyme disease. (Right) Axial FLAIR MR shows multiple hyperinlensities surrounding the red nuclei !:ll & in the basal ganglia 1:]. The combination of basal ganglia & midbrain involvement is lypical for a viral encephalitis, in this case due to West Nile virus.

West Nile Encephalitis

MUlTIPLE BRAIN HYPERINTENSITIES (T2/FlAIR), RAREBUT IMPORTANT

en

'c":

III

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lXl III

(Left) Coronal T2WI MR shows typical limbic encephalitis involving the medial temporal lobes =:I & right insular cortex PJ:I. This mimics herpes encephalitis, but lack of hemorrhage as we/J as cingulate involvement (not shown) favors limbic encephalitis. (Right) Axial FLAIR MR shows multiple, poorly marginated, (.f/.- confluent hyperintensilies in the periventricular, deep, & peripheral white mailer =:I with an outwardly radiating pattern seen in lymphoma.

:3

(Left) Axial T2WI MR shows disproportionate cerebellar =:I & pontine atrophy with cruciform T2 signal within t.he lower pons, the" hot cross bun" sign E±I characteristic for OPCD.

Note the normal supratentorial brain. (Right) Axial T2WI MR shows subcortical white maller hyperintensities III which have ill-defined margins &

spare the cortex. This is atypical for MS or stroke. SSPEusually ocwrs after a clinically silent period of months to years.

Rasmussen Encephalitis

Kernicterus (Leh) Axial T2WI MR shows ill-defined whit.e matter hyperintensities in the {rontal lobe within a larger region of striking atrophy of the frontal & parietal lobes. Rasmussen encephalitis. I-femicranium hypoplasia of Dyke-Davidoff-Mason & cortical hypointensity of Sturge-Weber are absent. (Right) Coronal T2WI MR

shows abnorrnal hyperintensity in the hippocampus =:I & globus pallidi PJ:I in a patient with age·appropriale immature myelin.

I 5 79

MULTIPLE HYPOINTENSE FOCI ON 12

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DIFFERENTIAL DIAGNOSIS Common • Neoplasm o Lymphoma o Metastases, Parenchymal o Multifocal Glioma • Atypical Infection o Bacterial (TB, Nocardia) o Fungal Diseases o Toxoplasmosis, Acquired Less Common • Neurosarcoid • Neoplasm-like Conditions o Post-Transplant Lymphoproliferative Disorder (PTLD) o Lymphomatoid Granulomatosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • These lesions show mild T2 hypointensity or "intermediate" signal intensity (51) o Lesions are often isodense or mildly hyperdense to gray matter (GM) on CT • Lesions in this ddx often associated with vasogenic edema & "bright" on T2/FLAIR, but are centrally iso- or hypointense to GM • Neoplasms included are generally small round blue-cell tumors (e.g., lymphoma) or highly cellular metastases with high nuclear-to-cytoplasmic ratio • DWI variable; may be mildly reduced due to t cellularity of some of these lesions

Helpful Clues for Common Diagnoses • Lymphoma o Both primary & secondary CN5 lymphoma may present as intermediate 51masses • PCN5L often limited to brain parenchyma • 5CN5L more likely to involve leptomeninges, dura, bone • Metastases, Parenchymal o Highly cellular, non-necrotic metastases o Breast & lung mets often T2 intermediate • Atypical Infection o Pyogenic abscesses typically have central t 51on T2WI because of pus o Atypical non-pyogenic "abscesses" often have intermediate 51on T2WI • In TB, due to caseous material • Fungal: Due to absence of pus, concentration of paramagnetic ions • Toxo: May show "eccentric target sign" o Variable reduced diffusion Helpful Clues for Less Common Diagnoses • Neurosarcoid o Parenchymal nodules & masses often intermediate T2 51due to high cellularity o Look for dural/leptomeningeal disease • Post-Transplant Lymphoproliferative Disorder (PTLD) o Parenchymal lesions resemble lymphoma • Lymphomatoid Granulomatosis o Rare lymphoproliferative disorder o Typical: Punctate & linear enhancement o Large coalescent nodules T2 intermediate

Metastases, Parenchymal

I 5 80

Axial T2WI MR shows multiple

brain parenchymal

masses lID with intermediate SI & variable associated vasogenic edema. The lesions enhanced intensely 8.. homogeneously- typical of primary eNS lymphoma.

Axial T2WI MR shows multiple lesions with associated

vasogenic edema. The 2 posterior lesions 1:.1 show fairly homogeneous intermediate 51, while the left frontal lesion I:i.'.l has a rim of low SI.

MULTIPLE HYPOINTENSE FOCI ON 12 III

::l

a. [ll .,

Multifocal

III

Glioma (Left) Axial T2WI MR shows areas of vasogenic edema in the right frontal & left temporal lobes, with central intermediate 51 ~ & associated mass effect The T2 hypointense central masses enhanced post-gadolinium. (Right) Axial T2WI MR shows multiple lesions that are intermediate in 5/ I:] & associated with vasogenic edema. These lesions showed ring enhancement. This patient had evidence for pulmonary TB as well as epididymo-orchitis.

Fungal Diseases

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CD

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(Left) Axial T2WI MR shows multifocallesions with intermediate 51centrally &/or involving

the rim with

significant vasogenic edema. Blood cultures were positive for Nocardia, a gram-positive bacillus, in this immunocompromised

patient. (Righi) Axial T2WI MR shows multiple centrally T2 hypointense lesions with associated vasogenic edema. Only minimal enhancement was seen, & this patient with disseminated aspergillosis was severely neutropenic.

1::1

(Left) Axial T2WI MR shows multiple

intermediate

=

5/

lesions with associated edema & mass effect in an HIV+ man. The lesions enhanced post-gadolinium. (Right) Axial T2WI MR shows mass-like areas of intermediate Sllissue & adjacent 10 the lateral ventricles & involving the choroid plexus. These masses enhanced intensely post-gadolinium. Confluent areas of increased 51 surrounding the temporal horns are consistent with transependymal flow of C5F.

I 5 81

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FOCI ON GRE/SWI

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DIFFERENTIAL DIAGNOSIS Common • Chronic Hypertension • Cerebral Amyloid Angiopathy (CAA) • Diffuse Axonal Injury (DAI) • Metastases, Parenchymal • Pneumocephalus Less Common • Vascular Malformations o Cavernous Malformation, Multiple o Multiple Micro-Arteriovenous Malformations • Infections o Neurocysticercosis o Tuberculomas o Fungal Diseases o Septic Emboli • Vasculitis • Vasculopathy • Radiation and Chemotherapy o Radiation-Induced Telangiectasia o Mineralizing Microangiopathy

•

•

•

Rare but Important • Coagulopathy • Leukemia • Metastatic Atrial Myxoma • Devices and Complications •

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • NECT may help with differential diagnosis o Air black on CT, calcification (Ca++) dense, hemosiderin staining not appreciable • GRE/SWI susceptibility generally greater for hemosiderin than for Ca++ • Distribution of GRE/SWI hypointensities o CAA typically peripheral/subcortical, while hypertension (HT ) changes are central o Subarachnoid involvement suggests pneumocephalus, cysticercosis • Gadolinium enhancement o eoplasm & infection generally enhance, whereas CAA, HTN changes, DAI do not

I 5 82

Helpful Clues for Common Diagnoses • Chronic Hypertension o Increased prevalence of GRE/SWI hypointensities related to "microbleeds"

Predominate in basal ganglia, thalami, brainstem (esp. pons), cerebellum Cerebral Amyloid Angiopathy (CAA) o Usually affects age> 6S years unless familial o Lesions predominantly juxta-cortical, cerebellar o Relative sparing of deep gray nuclei, brainstem o May coexist with HTN changes & Alzheimer disease o Often accompanied by moderate to severe small vessel ischemic changes in hemispheric white matter (WM) Diffuse Axonal Injury (DAI) o Classic triad: Lobar WM, corpus callosum, dorsolateral brainstem o History of severe head injury with acceleration-deceleration mechanism o Often associated with cerebral contusions, EDH/SDH, SAH, IVH Metastases, Parenchymal o Classically hemorrhagic mets: Melanoma, thyroid carcinoma, renal cell carcinoma, choriocarcinoma o Lung & breast cancer so prevalent, account for many cases of hemorrhagic metastasis o Hemorrhage may be seen at presentation or following treatment Pneumocephalus o Obvious on CT, can be confusing on MR o Often high signal edge surrounding low signal center, suggesting artifact o Seen post-trauma, post-surgical, CSF leak, spinal intervention o

Helpful Clues for Less Common Diagnoses • Vascular Malformations o Cavernous Malformation, Multiple • Occur both supra- & infratentorially • Autosomal dominant inheritance pattern • Not associated with developmental venous malformation o Multiple Micro-Arteriovenous Malformations • Occur in setting of HHT • Associated with vascular shunts & AVMs in other organ systems • Infections o Neurocysticercosis • Stage 4 lesions (chronic, healed) present as punctate & rounded Ca++ on CT

MULTIPLE HYPOINTENSE FOCI ON GRE/SWI

CIl

r:: ""

• Variable hypointensity on GRE Tuberculomas • Active lesions: Often central intermediate Sl on T2WI • Treated lesions: Often calcified, GRE/SWI hypointense • Often present with TB meningitis o Fungal Diseases • Invasive fungal infection is associated with multifocal brain parenchymal hemorrhage • Usually seen in severely imm unocompromised patients o Septic Emboli • Associated with multifocal infarction, often hemorrhagic • May result in microabscesses • Vasculitis o Brain micro hemorrhage may be due to primary or secondary CNS vasculitis • Vasculopathy o Small vessel vasculopathy (e.g., CADASIL or sickle cell disease) is associated with cerebral microbleeds & hemorrhage • Radiation and Chemotherapy o Brain radiation is associated with formation of multiple telangiectasias • Distribution conforms to radiation port • Increase over time o Chemotherapy • In combination with radiation may lead to mineralizing microangiopathy • Dense Ca++ on CT, variable loss of signal on GRE/SWI o

=-

Axial T2 CRE MR shows multiple hypointense foci in the central pons a characteristic location for hypertensive microhemorrhages. This patient also had a remote lobar hemorrhage Ei:I.

Helpful Clues for Rare Diagnoses • Coagulopathy o May cause hemorrhage into underlying lesions (metastasis, CAA) o "Spontaneous" hemorrhage may also occur • Leukemia o Microhemorrhages may indicate blast crisis • Metastatic Atrial Myxoma o "Oncotic" aneurysm may lead to SAH, parenchymal hematoma, or microhemorrhages • Devices and Complications o Cardiac valves; cardiopulmonary bypass • Patients who have been on bypass pump often have nonspecific punctate GRE hypointensities o Coils, methacrylate, other foreign materials • Aneurysm clips & coils usually cause GRE hypointensity outside & at base of brain • Coiling of more peripheral aneurysms may lead to signal loss that appears to be parenchymal • Embolic material in AVM

Gl C1l

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~

III

Alternative Differential Approaches • Patient's age o Older patient: CAA, HTN changes, metastatic disease, infection o Younger patient: DAl, infection, familial vascular malformations, iatrogenic

Axial T2' CRE MR more superiorly in the same patient shows characteristic hypertensive microhemorrhages in the thalami and basal ganglia =::I, as well as the remote right temporal hematoma Ei:I.

I 5 83

MUlTIPLE

co ~

HYPOINTENSE

FOCI ON GRE/SWI

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c Q)

(9

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Cerebral Amyloid Angiopathy

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(Left) Axial T2' CRE MR in a patient with a right frontal lobe hematoma shows innumerable microhemorrhages located predominantly in the periphery of the brain. This patient also has small vessel ischemic changes in the cerebral while maller. (Right) Axial T2' CRE MR shows that amyloid angiopathy may involve the cerebellum but typically spares the brainslem. In this

=

=

case cerebellar involvement is mild, 8, the supratentorial involvement is severe.

Diffuse

Axonal Injury

(Left) Axial T2' CRE MR shows multiple punctate foci of low signal intensity in the bifrontal parasagittal white matter This distribution is typical of OAI. The frontal lobes are often preferentially effected. (Right) Axial T2' CRE MR shows multiple foci of susceptibility in a patient with lung cancer metastases. Even if metastases are not initially hemorrhagic, they may hemorrhage after treatment 8, mimic pathology such as amyloid angiopathy.

=.

=

Pneumocephalus (Left) Axial T2' CRE MR shows multiple rounded foci of low signal intensity in the subarachnoid space (SAS). The patient had IVH E::I & recent posterior fossa craniotomy. The round shape of the lesions, their "shiny" periphery, 8, their SAS distribution suggest air. (Right) Axial T2' CRE MR shows multiple foci of low signal intensity in the frontal & parietal lobes. There are 2

=

=

dominant

I 5 84

lesions on the left

8, punctate nonspecific ks0nsonther~ht~

(DAI)

Metastases, Parenchymal

(CAA)

MULTIPLE HYPOINTENSE

FOCI ON GRE/SWI

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c: III

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Multiple Cavernous Malformation,

Multiple

Micro-Arteriovenous Malformations

OJ ....• III

(Left) Axial T2WI MR in the prior patient shows "mulberry" appearance & peripheral hemosiderin staining

of one

=

cavernous

malformation & a fluid-fluid level in another 1J:!lI. The punctate additional cavernous

malformations

are

OJ ...•• OJ

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'< 3

not seen on this FSE T2WI. (Right) Axial T2* CRE MR

OJ

shows several large

(t)

hemorrhagic lesions in the brain as well as multiple punctate foci of susceptibility This HHT patient had prior brain & pulmonary hemorrhages.

(t)

=

Neurocysticercosis

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Fungal Diseases (Left) Axial T2' CRE MR shows multifocal hypointensities scattered throughout the sulci, parenchyma, & ventricles. Some of these lesions showed ring enhancement on T1 C+ scans, & many were calcified on CT (not shown). (Right) Axial T2' CRE MR shows multiple foci of hemorrhage along the course of the penetrating

medullary vessels in a patient with AML & fungal sepsis. Autopsy confirmed disseminated aspergillus infection.

Vasculitis

Radiation-Induced

Telangiectasia (Left) Axial T2 CRE MR shows punctate foci of CRE susceptibility in a patient with known lupus vasculitis. (Right) Axial T2* CRE MR shows multiple foci of CRE hypointensity in the brain parenchyma & signal loss due to a right cranioplasty ~. This patient had prior

=

=

radiation treatment of an astrocytoma as well as surgical resection of a radiation-induced meningioma.

These lesions

are consistent with radiation·induced telangiectasias.

I 5 85

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11/12 HYPERINTENSE

PARENCHYMAL lESIONS

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DIFFERENTIAL DIAGNOSIS Common • Intracerebral Hematoma • Cavernous Malformation • Cerebral Amyloid Disease less Common • Multiple Sclerosis • Neurofibromatosis Type 1 • Metastases, Parenchymal • Cerebral Infarction, Subacute Rare but Important • Lymphoma, Primary CNS • Lipoma • Fahr Disease

ESSENTIAL INFORMATION

I 5 86

• Rim "ages" faster than center Early subacute parenchymal hemorrhage • Typically 3-6 days • Contains methemoglobin within RBCs • Tl shortening in periphery • Isointense centrally • Profound T2 hypointensity o Late subacute/early chronic hemorrhage • Cells lyse, release methemoglobin • Extracellular dilute free methemoglobin demonstrates diffuse Tl shortening, T2 prolongation • Hematoma demonstrates hyperintensity on both Tl/T2WI • Develops hypointense rim • Cavernous Malformation o Zabramski type 1 = subacute hemorrhage • Hyperintense on Tl WI • T2 signal depends on hematoma stage • Early subacute: Hypointense on T2WI • Late subacute: Hyperintense on T2WI o Zabramski type 2 = mixed signal (classic "popcorn" ball) • Fluid-fluid levels in multiple "caverns" • Iso-/hyperintense on Tl WI • Hypo-/hyperintense on T2WI • Complete T2-hypointense hemosiderin rim surrounds lesion • Important: Do T2* scan (GRE/SWI) to look for multiple lesions • Cerebral Amyloid Disease o Elderly normotensive demented patient o Look for multiple parenchymal hemorrhages of different ages • Subacute hematomas are hyperintense on both Tl/T2Wls • Do T2* sequence! • > 50% have multiple cortical/subcortical "black dots" (micro hemorrhages) • CAA microbleeds rare in cerebellum, basal ganglia (typical for chronic hypertensive encephalopathy) o

Helpful Clues for less Common Diagnoses • Multiple Sclerosis o Most MS plaques are hypointense on Tl WI, hyperintense on T2WI o Chronic plaques may develop faint hyperintense "ghost" or "rim" on Tl WI that surrounds hypointense lesions o Deep periventricular white matter most common location

11/T2

HYPERINTENSE

PARENCHYMAL

lESIONS

en ,.. r::

• Neurofibromatosis Type 1 a Bilateral basal ganglia hyperintensity common in NFl a Foci of abnormal signal intensity ("FASIs") on T2WT represent myelin vacuolization, clumping, disappear with age • Metastases, Parenchymal a Most are iso-/hypointense on Tl WI a T2 signal intensity variable a Metastases with subacute hemorrhage or melanin may display Tl shortening • Cerebral Infarction, Subacute a Hemorrhagic transformation • Typically occurs between 2-5 days • Foci of punctate or gyriform Tl shortening • T2 hyperintensity typically much larger • Basal ganglia, cortex most common sites Helpful Clues for Rare Diagnoses • Lymphoma, Primary CNS a Classic primary CNS lymphoma is solid infiltrating tumor a Typically isointense with gray matter on both Tl/T2WIs a AIDS-related lymphoma • Increasing prevalence • Hemorrhage, necrosis common • Hyperintense on both Tl/T2WTs • Ring or "target" enhancement • Lipoma a Fat is not normal in CNS (i.e., inside arachnoid) anywhere!

CNS lipomas are congenital malformations, not neoplasms a Typically located in subpial space along brain surfaces a On standard spin-echo imaging, fat is hyperintense on Tl WI, hypointense on T2WI a Because of ]-coupling, lipomas are hyperintense on both Tl and T2-weighted fast spin echo scans a Look for chemical shift artifact a To confirm, do fat-suppressed sequence • Fahr Disease a Also known as cerebrovascular ferrocalcinosis or bilateral striopallidodentate calcinosis a Degenerative neurologic disorder with extensive, typically bilaterally symmetrical nonarteriosclerotic calcifications a Some cases have bizarre-appearing hyperintensities on both Tl/T2WIs corresponding to dense parenchymal calcifications a

G) (1)

:::l (1)

~ Ql

Intracerebral Hematoma

Axial T1WI MR showstypicaJ late subacute intracerebral hematoma with homogeneous hyperintensity due to extracellular dilute methemoglobin.

Axial T2WI MR in the same patient as the previous image shows that the hematoma remains hyperintense.

I 5 87

T1/T2

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HYPERINTENSE

PARENCHYMAL

LESIONS

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previous image shows the

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mass remains mostly hyperintense on T2WI with nodule ~ demonstrating typical "popcorn ball" mixed

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Cavernous Malformation

Cavernous Malformation

Multiple Sclerosis

Multiple Sclerosis

(Left) Axial T7 WI MR shows mostly hyperintense left parietal mass ~ with a small mixed signal intensity nodule ~ (Right) Axial T2WI MR in the same patient as the

signal intensity.

(Left) Axial T7WI MR shows a subacute hemorrhage in right temporal lobe. A more acute left parietal

hemorrhage

= is almost

completely isoimense with brain. (Right) Axial T2WI MR shows that subacute right tempora/lobe

hematoma

remains hyperintense

to

brain while more acute left

parietal

hemalOma

11Im

appears inhomogeneously hypointense.

(Left) Axial T7 WI MR in a patient with long-standing MS shows multiple ovoid white maller lesions. Lesions are mostly hypointense, have faint but definite "ghost-like" hyperintense rims ~ ("lesion within a lesion" appearance). (Right) Axial T2WI MR in the same patient

as the previous image shows lesions are uniformly

hyperintense. Note classic perivenous demyelinating plaques within prominent perivascular spaces.

=

I 5 88

11/T2

HYPERINTENSE

PARENCHYMAL

,..c:

LESIONS

Ul

III

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Metastases, Parenchymal (Left) Axial T7WI MR in a with known metastatic melanoma shows multiple hyperintense foci at the gray-white matter junction. (Right) Axial T2WI MR in the same patient as patient

=

the previous image shows Jargesllesion remains hyperiniense ffi Chronic hemorrhage is seen around

second metastasis

=-

left-sided lesion barely visible with mild edema ~.

Cerebral

Infarction,

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Subacute (Left) Sagittal T7WI MR in a patient with subacute right middle cerebral infarct shows faint hyperintense foci in cortex !:J indicating hemorrhagic

transformation.

(Righi) Axial T2WI MR shows farge hyperintense right MCA infarct~. A small focus of more acute hemorrhagic transformation is seen 1m.

fLeft) Axial T7 WI MR in a patient with HIV/AIOS shows bilateral inhomogeneously hyperintense lesions in basal ganglia, suggesting subacute hemorrhage (Right) Axial T2WI MR in an HIV/AIOS patient shows moderately but inhomogeneousJy hyperintense lesions in both basal ganglia CNS lymphoma in immunocompetent patients is usually isointense with gray matter on both T7/T2WI.

=.

I 5 89

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DIFFERENTIAL DIAGNOSIS Common • Enlarged Perivascular Spaces • Arteriolosclerosis • Chronic Hypertensive Encephalopathy • Cerebral Amyloid Angiopathy • Lacunar Infarction • Demyelinating Disease o Multiple Sclerosis o ADEM o Susac Syndrome • Encephalomalacia o Post-Traumatic o Post-Ischemic • Neurocysticercosis • Cerebral Contusion • Diffuse Axonal Injury (DAI) Less Common • Primary Brain Tumor o Diffuse Astrocytoma, Low Grade o Anaplastic Astrocytoma o Glioblastoma Multiforme o Oligodendroglioma o Gliomatosis Cerebri • Metastases, Parenchymal • Abscess • Cerebral Amyloid Disease • Encephalitis o Herpes Encephalitis o Encephalitis (Miscellaneous) • Cerebritis • Vasculitis • Neurofibromatosis Type 1 • Tuberous Sclerosis Complex Rare but Important • Neurosarcoid • Radiation and Chemotherapy • Inherited Leukodystrophies (Many)

ESSENTIAL INFORMATION

I 5 90

Key Differential Diagnosis Issues • Very broad differential diagnosis • Most parenchymal masses, benign or malignant, are hypointense on Tl-, hyperintense on T2WI • Look for presence/absence of mass effect, enhancement, blooming on T2* GRE/SWI, diffusion restriction, etc., to help narrow differential diagnosis

• Location generally less helpful (some exceptions like herpes encephalitis, Fl, TSC, enlarged PVSs) Helpful Clues for Common Diagnoses • Enlarged Perivascular Spaces o All locations, all ages but most common in basal ganglia/around anterior commissure, in midbrain, dentate nuclei, hemispheric white matter o Contain interstitial fluid; follow CSF signal on all sequences o May cause focal mass effect (expanded gyri, occasionally cause aqueductal obstruction) o May look bizarre, mimic neoplasm but spare cortex, do not enhance • Arteriolosclerosis o Small vessel ischemic changes ("microvascular disease") o Scattered or confluent white matter/basal ganglia hypointensities on Tl WI, hyperintense on T2WI o No enhancement o Patients generally older, often hypertensive • Chronic Hypertensive Encephalopathy o Look for confluent lesions around atria of lateral ventricles o Do T2* (GRE or SWI) to look for microbleeds (central> peripheral) • Cerebral Amyloid Angiopathy o Elderly normotensive demented patients o Hemorrhages of different age, peripheral microbleeds on T2* • Demyelinating Disease oMS> > ADEM • History of viral illness, recent immunization suggests ADEM o Susac Syndrome • Rare; often mistaken for MS! • Young to early middle-aged females • Progressive encephalopathy, sensorineural hearing loss, visual symptoms • "Holes" in middle of corpus callosum Helpful Clues for Less Common Diagnoses • Primary Brain Tumor o Most primary brain neoplasms typically hypointense on Tl WI, hyperintense on T2WI; may be difficult to distinguish neoplastic from nonneoplastic etiologies

T1 HYPOINTENSE,12

•

•

•

•

HYPERINTENSE

• DWI helpful (neoplasms generally don't restrict; ischemia/infarction, infection typically do) • MRS helpful in some cases (t Cho) o Presence/absence/pattern of enhancement helpful but often nonspecific o Tend to be infiltrative rather than discrete, round masses Metastases, Parenchymal o Tend to be round rather than infiltrative o Gray-white junction common location o Almost always enhance (ring, punctate, solid) o May cause multifocal white matter hyperintensities, mimic "small vessel disease" o Difficult to detect or differentiate from vascular disease without contrast Abscess o Early cerebritis stage can be difficult to distinguish from ischemia, neoplasm o Late cerebritis to late capsule stages show ring enhancement o DWI restriction at all stages typical o MRS often shows lactate, amino acid peaks Cerebral Amyloid Disease o Can be multifocal, diffuse (amyloid angiopathy) • Do T2* (GRE/SWI) to detect micro bleeds • Peripheral> central (basal ganglia) o Lobar (hemorrhages of different ages) o Mass-like ("amyloidoma" rare) Herpes Encephalitis o Affects limbic system

Enlarged Perivascular

not enhance.

c: "

• Temporal lobes, insular cortex • Cingulate gyrus, subfrontal cortex o Look for "sequential bilaterality" in temporal lobes o Preferentially involves cortex o FLAIR,DWI most sensitive for early detection o Hemorrhage with TI shortening in late acute/subacute stages • Vasculitis o Can be primary CNS or secondary to systemic disorder o Combination of cortical/subcortical, basal ganglia disease suggestive o Punctate/linear enhancement common • Neurofibromatosis Type 1 o Foci of abnormal signal intensity best seen on T2WI, FLAIR o Hypointensities on TI WI less common; basal ganglia may have hyperintensity o Typically represent myelin vacuolization, not demyelination; are transient (rarely seen in adults) o No enhancement; if present, suggests possibility of astrocytoma (usually pilocytic) • Tuberous Sclerosis Complex o Cortical/subcortical tubers hypointense on TI, hyperintense on T2WI (similar signal to WM lesions of NFl) o Look for other stigmata of TSC (e.g., subependymal nodules, lesions along radial glial bands)

Spaces

Axial T2WI MR shows bizarre va,iable-sized hyperintense white matter cysts with gyral expansion cortical sparing lesions followed CSFon TI WI, did

en

PARENCHYMAL lESIONS

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Arteriolosclerosis

Sagittal TI WI MR in a patient with clinical diagnosis of Binswanger

vasculaNype

dementia

shows

mu/tjfocal

discrete and confluent lesions in subcortical, deep perivent/ieu/ar white maller _

I 5 91

T1 HYPOINTENSE,12

HYPERINTENSE

PARENCHYMAL

lESIONS

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(Leh) Axial T2WI MR shows several types o( T2 hyperintense lesions: Chronic hypertensive encephalopathy (typically periatrial changes) 1C>1 lacunar infarcts [;>1 prominent perivascular spaces ffi (RighI) Axial T2WI MR shows multifocal hyperintensities in subcortical white matter Presence of acute chronic 81 hemorrhage plus

= =.

peripherallocalion

is

characteristic for CAA.

(Lefl) Sagittal T7 WI MR in this patient with known MS shows deep perivenlricular hypointense lesions oriented perpendicular to the ventricular margin These lesions are perivenular demyelinating MS plaques. (RighI) Axial T7WI MR shows discrete, ill-defined hypointense foci ~ in a patient with a history of

recent viral illness. Many additional lesions were present on fLAIR, T2WI.

Susac Syndrome (Lefl) Sagittal T7 WI MR shows multifocal hypoinlensilies in the middle of the corpus callosum I:] in this 31 year old man with encephalopathy,

sensorineural hearing loss, visual symptoms. (Courtesy P. Rodriguez, MO). (RighI) Axial T2WI MR in a patient with decreasing mental status shows mulliFocal white maller

hyperinlensilies

lID.

Severa/lesions enhanced with contrast. Breast carcinoma

I 5 92

was found on

Further evaluation.

Metastases,

Parenchymal

11 HYPOINTENSE,12

HYPERINTENSE

PARENCHYMAL

lESIONS III

::l

Co

..,

OJ III

(Left) SagiLral T1 WI MR in polydrug abuser shows 2 inhomogeneously hypointense lesions that enhanced slrongly with contrast and showed reSlriction on DWI. (RighI) Axial T1WI MR shows diffuse cortical swelling, hypointensity in left temporal lobe with less prominent involvement of right temporal lobe SI. Bilateral disease suggests herpes encephalitis.

=

=

Cerebritis

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Vasculitis (Lefl) Axial T1 WI MR in a 16 yo with headache, nausea developing 2 weeks after URI shows in homogeneously hypointense mass in right temporal lobe T1 C+ scan (nol shown) demonstrated poorly delineated enhancing rim characteristic for early cerebritis stage of abscess. (RighI) Axial T2WI MR shows hyperintense basal ganglia, thalami in this young female patient with known systemic lupus erythematosus and probable SLE vasculitis.

(Lefl) Axial T1 WI MR shows an optic chiasm astrocytoma hypointense foci in pons [;8 Pontine lesions were hyperintense on T2WI. (RighI) Axial T1 WI MR shows a large, flat gyri with hypointense juxtacorlical lesions in muflipfe tubers and white matter, as well as numerous calciried hyperintense subependymal nodules ffi Subcortical lesions were hyperintense on T2WI, fLAIR.

=-

I 5 93

~

11/12 IsOINTENsE PARENCHYMAL lESIONS

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DIFFERENTIAL DIAGNOSIS Common • Cerebral Ischemia-Infarction, Hyperacute • Intracerebral Hematoma (Hyperacute) • Capillary Telangiectasia • Developmental Venous Anomaly • Meningioma

•

less Common • Metastases, Parenchymal • Lymphoma, Primary CNS Rare but Important • Neurosarcoid • Heterotopic Gray Matter • Tuber Cinereum Hamartoma • Tuberous Sclerosis Complex • Cerebral Infarction, Subacute

•

ESSENTIAL INFORMATION

•

•

I 5 94

• Look for "dot sign" (intravascular high signal intensity caused by occlusion/slow flow) • Found in 10% of patients with acute stroke Intracerebral Hematoma (Hyperacute) o Clot contains intracellular oxyhemoglobin, which is diamagnetic o Although hyperacute clot can be isointense on Tl WI, most hematomas are inhomogeneous, often hyperintense on T2WI Capillary Telangiectasia o Can be anywhere • Pons, medulla> supratentorial cortex, white matter o Imaging • Unless unusually large, typically invisible on Tl/T2WI • Use T2* sequence (become hypointense on GRE, SWI) • Tl C+ shows "brush-like" enhancement • May see tiny central draining vein within lesion Developmental Venous Anomaly o Most common cerebrovascular anomaly o Imaging • If small, often invisible on Tl/T2WI • Larger DVAsmay have discernible flow void or flow-related enhancement • If slow flow in "Medusa head" (medullary veins), may become hypointense on T2* (GRE/SWI) • Best seen on Tl C+ Meningioma o Not truly a parenchymal lesion although some may invaginate into brain o Included because often isointense to cortex, difficult to detect on nonenhanced TlWI, T2WI o Look for signs of extra-axial location • Gray-white matter "buckling" • CSF-vascular "cleft" o Most enhance on Tl C+

Helpful Clues for less Common Diagnoses • Metastases, Parenchymal o Most hyperintense on FLAIR,T2WI o Gray-white matter junction distortion • Few are isointense on both Tl/T2WI • Most (not all) have detectable edema

T1/12

ISOINTENSE

PARENCHYMAL

lESIONS

(J)

""c:

• Look for subtle alteration in gyral shape, sulcal effacement o Most enhance • Lymphoma, Primary CNS o Hypercellular tumor, high nuclear:cytoplasm ratio • Isointense (cortex, basal ganglia) on both Tl/T2WI • Hemorrhage, necrosis rare unless HIV/AIDS o Look for anatomic distortion of deep periventricular structures o Almost always enhances Helpful Clues for Rare Diagnoses

• Neurosarcoid o Can be anywhere, look like almost anything! o Dural-based masses> > parenchymal lesions o Infiltration along perivascular spaces parenchymal masses o Isointense on Tl WI • Typically hyperintense on T2WI, FLAIR • Exception: Lesions in infundibular stalk usually isointense on all sequences o Enhance strongly, sometimes heterogeneously • Heterotopic Gray Matter o Isointense to cortex on all sequences, no enhancement o Can be cortical, subcortical white matter, subependymal

Cerebral

Ischemia-Infarction, Hyperacute

Axial T2WI MR shows very subtle focus of white matter hyperintensity in right posterior frontal lobe ~ tI,at is isointense with gray maHer. OWl showed anterior MCA division

infarct.

Beware: Masses of heterotopic gray matter can distort ventricle, mimic tumor! • Tuber Cinereum Hamartoma o Typical clinical presentation • Young male with isosexual precocious puberty • Gelastic seizures o Imaging • > 90% isointense with cortex on all sequences • 10% cystic, slightly hyperintense on PD, FLAIR,T2WI • Tuberous Sclerosis Complex o Cortical "tubers" • Thickened gyri • "Blurred" gray-white interface • Mostly isointense with cortex, occasionally hyperintense o Subependymal nodules • Mostly isointense with white matter • Variable, often heterogeneous intensity if densely calcified • May enhance on Tl C+ • If enhancing SEN at foramen of Monro, surveillance to watch for giant cell astrocytoma warranted • Cerebral Infarction, Subacute o Imaging • 10 days to 2 weeks after ictus • MR "fogging effect" may render stroke isointense on Tl/T2WI • DWI may pseudonormalize • Lesion typically enhances o

Intracerebral

Hematoma

III

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CD

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(Hyperacute)

Axial T7WI FS MR in a patient with AML, acute clinical deterioration with normal NEeT minutes before this scan shows left frontal lesion ~ isointense with cortex. T2W/showed expanding hematoma.

I 5 95

11/12

ro ~

ISOINTENSE

PARENCHYMAL

LESIONS

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Developmental

Metastases, (Lefl) Axial T1WI MR shows left parietal sulcal effacement by an isointense, dural-based mass ~ (RighI) Axial T1 WI MR in

a

patient

with known

metastatic breast cancer shows expansion of left posterior frontal gyri by mass that is so completely ;sointense with brain that it can't be identified separately from surrounding

normal

parenchyma.

(Lefl) Axial T1WI MR shows corpus callosum thickening and expansion by an ;sointens€ mass that demonstrated strong homogeneous enhancement (not shown). Primary CNS lymphoma was documented on stereotaxic biopsy. (RighI) Axial T2WI MR in the same

=

as previous image shows corpus callosum patient

splenium

lesion

remains

mostly isointense with cortex but is slightly hyperintense to

I S 96

Venous Anomaly

(Left) Axial T2WI MR shows no discernible abnormality. T2' CRE scan (not shown) disclosed hypointense pontine lesion with "brush-like" enhancement following contrast administration. Most capillary telangiectasias are not detectable on either T1 or T2Wls. (RighI) Axial T1 WI MR shows flow void of OVA transmantle draining vein. Enlarged medullary radicles constituting OVA ~ are almost invisible but enhanced strongly on T1 C+ scan.

white maller.

Adjacent

edema Ell is hyperintense.

Parenchymal

11/12

ISOI NTENSE PARENCHYMAL

en

lESIONS

c: " III

:l Co

OJ .,

Heterotopic

Gray Malter

Heterotopic

III

Gray Malter (Left) Axial TI WI MR shows

:l

bilaleral

OJ .,

subependymal nodules of heterotopic gray mailer 8 that are isointense with cortex. (RighI) Axial T2WI MR in the same patient as the previous image shows the nodules of heterotopic

OJ :l

extensive

gray maller

isointense

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with cortex.

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Tuber Cinereum

Hamartoma (Left) Sagittal Tf WI MR in a 9 year old boy with precocious puberty shows a sessile mass in the hypothalamus/Jrd ventricfe floor. (RighI) Axial TlWI MR shows multiple cortical tubers isointense with gray mailer subependymal nodules [;8 mostly isoinlense

=

with white maller.

Cerebral

Infarction,

Subacute

Cerebral

Infarction,

Subacute (Left) Axial Tf WI MR 2 weeks aFter right occipital infarct shows no definite

abnormality. (RighI) Axial T2WI MR in the same patient as the previous image shows only slight hyperintensity =:I with most of the affected cortex /lOW isoinlense

1/

with

of T2 Fogging" effect in subacute

normal

brain because

infarction.

I 5 97

RESTRICTEDDIFFUSION

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DIFFERENTIAL DIAGNOSIS Common • Cerebral Ischemia-Infarction, • Abscess • Empyema • Epidermoid Cyst

Acute

Less Common • Intracerebral Hematoma • Diffuse Axonal Injury (DAI) • Encephalitis (Miscellaneous) • Meningioma • Primary CNS Lymphoma • Acute Hypertensive Encephalopathy, • Creutzfeldt-]akob Disease (C]D) • Multiple Sclerosis • Osmotic Demyelination Syndrome • Status Epilepticus • Hypoglycemia • Wernicke Encephalopathy

PRES

ESSENTIAL INFORMATION

I 5 98

Key Differential Diagnosis Issues • Clinical history can help differentiate between various etiologies: Infection, stroke, and neoplasm • Morphology &/or location useful a Vascular distribution or wedge-shaped: Ischemia a Round "cystic" T2 hyperintense lesions: Abscess, septic emboli a Solid intermediate-low signal T2 round lesions: Solid ce]Jular masses (e.g., lymphoma, metastases, meningioma) a Extra-axial cyst: Epidermoid (cholesteatoma in temporal bone) a Central pontine &/or deep nuclei: CPM/EPM, deep venous ischemia, PRES • Degree of DWI hyperintensity is useful a Subacute & evolving strokes have less intense DWI brightness as cytotoxic changes fade over time & are replaced by progressively increasing vasogenic edema a Hypoperfusion infarcts usually have less intense DWI brightness a Inflammatory/infectious causes for diffusion restriction are characteristically less hyperintense than acute stroke • Check ADC map to confirm true restriction!

Helpful Clues for Common Diagnoses • Cerebral Ischemia-Infarction, Acute a Abrupt clinical onset a Occur in a vascular distribution a Punctate white matter (WM) lesions often of small vessel origin • May be clinically silent a Venous ischemia may have increased or mixed DWI changes; often hemorrhagic • Abscess a Restriction centrally in "cystic" or ring-enhancing lesions a T2 hypointense rim characteristic a DWI restriction may be seen in bacterial, granulomatous, or parasitic infections (e.g., neurocysticercosis) • Toxoplasmosis has variable DWI • Empyema a Peripheral rim enhancement typical a Extra-axial fluid coJJections that restrict are usually pus-filled • Mimic: Extra-axial hematomas • Epidermoid Cyst a Lobular extra-axial mass follows CSF intensity except on FLAIR& DWI a DWI (usually markedly bright) is more specific than FLAIR(may be bright or subtle "dirty CSF"); both show increased signal relative to CSF a Cholesteatoma of middle ear or petro us apex histologically same & DWI bright (thin slice DWI helpful) Helpful Clues for Less Common Diagnoses • Intracerebral Hematoma a DWI signal variable; bright or "black" a Conventional Tl/T2 sequences & clinical history help to distinguish a GRE sequence may clarify (susceptibility reflects blood products in most stages of hemorrhage evolution except early hyperacute) • Diffuse Axonal Injury (DAI) a Classic locations: Gray-white junction, deep WM, corpus callosum, brainstem a Typically bright on DWI a Other useful sequences: FLAIR,GRE, SWI • Some foci appear only on some MR pulse sequences • DAI may be hemorrhagic or nonhemorrhagic a Trauma history

RESTRICTED DIFFUSION

• Encephalitis (Miscellaneous) o DWI signal is variable: Increased, mixed, or decreased o Bright DWI signal is usually less intense than seen with acute ischemia & abscess o T2 hyperintense lesions • Meningioma o Mild restriction common due to cellularity o Enhancing extra-axial mass • Primary CNS Lymphoma o Often DWI bright due high cellularity o Periventricular location & homogeneous enhancement typical • Acute Hypertensive Encephalopathy, PRES o T2 hyperintensity in posterior circulation bilaterally in a hypertensive patient o Usually doesn't restrict on DWI!! • Vasogenic edema (t diffusion) > > cytotoxic edema (restricted diffusion) • If DWI restriction present - poor prognosis (indicating progression to infarction) o Critical to assess ADC to separate the 2 components, both may be present • Creutzfeldt-Jakob Disease (CJD) o DWI restriction in basal ganglia (BG), thalami ± cortical ribbon (esp. insula) o DWI hyperintensity increases over time o Older patient with rapidly t dementia • Multiple Sclerosis o Demyelination rarely causes restriction o Most show increased diffusion on ADC o Callososeptallesions characteristic

Cerebral

Ischemia-Infarction,

Acute

• Osmotic Demyelination Syndrome o May restrict acutely o Classic locations (pons, BG) & clinical picture diagnostic • Status EpiIepticus o DWI restriction occurs in the acute-subacute phases, involving cortex & hippocampi most commonly o Usually a patient in status for prolonged time period (often 24+ hours) • Hypoglycemia o Bioccipital, parietal lesions typical o Clinical history usually confirmatory • Wernicke Encephalopathy o Restriction in/around 3rd ventricle & midbrain o Mamillary body, medial thalamus, hypothalamus, & periaqueductal gray bilateral T2 hyperintensity & enhancement

Cerebral

Ischemia-Infarction,

=::I

due to vein of

ischemia.

OWl in acute

Axial OWl MR shows high signal Labbe thrombosis

cerebral

venous ischemia more commonly demonstrates vasogenic or mixed vasogenic & cytotoxic edema.

lenticulostriate arteries.

~

Acute

Axial OWl M R shows artery

Cl> 0>

Other Essential Information • Round foci of DWI restriction that resemble abscess MUST be correlated with conventional MR images o Homogeneously enhancing solid masses that restrict are usually cellular neoplasm • Especially if relatively T2 iso- to hypointense o Densely cellular tumors can restrict (due to high nuclear:cytoplasmic ratio) • Lymphoma, PNET, medulloblastoma; some metastatic diseases, meningioma

poste,ior temporal region

restriction in the caudate & =::I related to acute middle ischemia with involvement of the

G) Cl> :J

& venous

I 5 99

RESTRICTED

~

DIFFUSION

c
<.9 ell

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c

~

CI)

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III

Abscess

Empyema

(Left) Axial OWl MR shows central restriction within a ring·enhancing left parietal lesion consistent with abscess. This abscess was complicated by intraventricular rupture and ventriculitis which has a poor prognosis. (Right) Axial OWl MR shows restriction in bifrontal epidural fluid collections =::I related 10 empyemas, a complication of this patient's frontal sinusitis. Epidural hematomas may have a similar imaging appearance.

=..

a

Epidermoid

Cyst

Diffuse Axonal Injury (DAI)

(Left) Axial OWl MR shows classic findings of markedly restricted diffusion within an extra-axial cystic structure anterior to the medulla consistent with epidermoid. An arachnoid cyst, a mimic on conventional imaging, would show dark CSF signal on OWl MR. (Right) Axial OWl MR shows a typical case of OAI involving the left thalamus =::I & right temporal deep white maller near the gray-white matter junction 81. CRE or SWI may show additional OAI foci.

=-

Encephalitis

I 5 100

(Left) Ax;al OWl MR shows increased signal in the medial left temporal lobe =:I in this 25 year old with herpes encephalitis. Herpes encephalitis typically involves the gray matter of the limbic system & is bilateral, but asymmetric. (Right) Axial OWl MR shows restricted diffusion in a parenchymal & dural-based left anterior temporal mass =:I in this patient with secondary Nt-Ii. Both primary & secondary lymphoma may show OWl restriction.

(Miscellaneous)

Primary CNS Lymphoma

RESTRICTED DIFFUSION

(JJ

"

c:

Acute Hypertensive Encephalopathy, PRES

Acute Hypertensive Encephalopathy, PRES (Left) Axial OWl MR shows hyperintensity in the posterior circulation bilaterally =:I in this patien! with known PRES. The presence 01 cytotoxic edema in PRESindicates a poor prognosis and usually reflects irreversibly infarcted tissue. Conlirmation with AOC maps is important, however. (Right) Axial AOC shows mixed difFusion characteristics, with areas of (bright) vasogenic edema 8lI & (dark) cytotoxic edema 1:::1 in the same patient as the previous

Creutzfeldt-Jakob

Disease (CJD)

Multiple

Gl CO :J CO

~ Ql

image.

Sclerosis (Lelt) Axial OWl MR shows increased signal without mass effect involving the caudate nuclei typical 01 CIO. Symmetric involvement 01 the caudate & putamen is

=-

more common than involvemen! 01 the globus pallidus or thalamus. (Right) Axial OWl MR shows a presumed acutely restricting plaque =:I in a young patient with known MS and recent exacerbation. These focaf lesions may be dillicult to differentiate

from acute

ischemia.

Osmotic

Demyelination

Syndrome

Status Epilepticus (Left) Axial OWl MR shows acute restriction in the central pons in this patient with a rapid correction of hyponatremia. Central pontine myelinolysis may show restricted diffusion & enhancement in the acute selling. (Right) Axial OWl MR shows mild dilluse linear hyperintensity along the lelt parietal and temporal cortex in this patient with status epilepticus. These MR changes may resolve completely or result in mild regional atrophy.

=

=

I 5 101

ro ~

11 HYPERINTENSE

PARENCHYMAL

LESION(S)

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ltl

DIFFERENTIAL DIAGNOSIS

a

Common • Mineral Deposition a Physiologic Calcification a Trace Element Deposition • MR Artifacts, Flow-Related • Intracerebral Hematoma (Late Subacute) Less Common • Multiple Sclerosis • Metastases • Cerebral Amyloid Disease • Cavernous Malformation • Neurocutaneous Syndromes a Neurofibromatosis Type 1 a Tuberous Sclerosis Complex Rare but Important • Hypoxic-Ischemic Injury a HIE, NOS a Cerebral Infarction, Chronic a Cortical Laminar Necrosis • Acute Hypertensive Encephalopathy, PRES • Encephalitis a Herpes Encephalitis a Encephalitis (Miscellaneous) • Melanin Deposition a Melanoma Metastases a Meningeal Melanocytoma a Neurocutaneous Melanosis • Thrombotic Microangiopathies (HUS/TTP) • Fabry Disease • Fahr Disease • Fungal Diseases • Kernicterus • Leukemia • Dermoid Cyst (Ruptured)

ESSENTIAL INFORMATION

I 5 102

Melanin Hypoxic-ischemic injury as well as nonhemorrhagic cerebral infarction a Remyelination/hypermyelination a Macrophage infiltration • Phagocytosis, paramagnetic free radicals a

Key Differential Diagnosis Issues • Short Tl on Tl WI scan related to a Deposition of paramagnetic substances • Methemoglobin • Non-heme iron (e.g., ferritin) a Mineral deposition (e.g., calcium) • Calcification • Trace element deposition a Fat a Melanin a Proteinaceous materials a Increased lipid or cholesterol content

Helpful Clues for Common Diagnoses • Mineral Deposition a Bilateral, symmetrical a Basal ganglia most common location • MR Artifacts, Flow-Related a Look for propagation across image a Entry phenomena, phase artifact • Intracerebral Hematoma (Late Subacute) a Age-related causes • Young patients: Vascular malformation, neurocutaneous syndrome, blood dyscrasias, metabolic disorders • Elderly patients: Hypertension (basal ganglionic), amyloid (lobar, peripheral) hemorrhagic metastases a Check history • Trauma: Hemorrhagic DAI, contusions (typical locations) • Infection: Abscess, encephalitis Helpful Clues for Less Common Diagnoses • Multiple Sclerosis a Look for hazy "rim" or "ghost" of Tl shortening around chronic lesions • Metastases a Hemorrhagic (renal cell, melanoma) a Melanoma (hemorrhagic vs. intrinsic Tl shortening from melanin) • Cerebral Amyloid Disease a Lobar, cortical/subcortical a Hemorrhages of different ages • Cavernous Malformation a Can be single or multiple, large or small, homogeneous or "popcorn" appearance • Neurocutaneous Syndromes a Neurofibromatosis Type 1 • Basal ganglia, internal capsules • Symmetric Tl shortening due to myelin clumping or microscopic calcification a Tuberous Sclerosis Complex • Subependymal nodules often hyperintense on noncontrast Tl WI • Cortical tubers hyperintense early (unmyelinated brain), variable later • Streaky or wedge-shaped white matter hyperintensities (unmyelinated brain)

11 HYPERINTENSE PARENCHYMAL LESION(S)

CIl

c: ""

• Taylor-type cortical dysplasias may initially be hyperintense (unmyelinated brain)

Hemorrhagic lesions • Hematoma (subacute) • Infarct (hemorrhagic transformation) • Trauma (contusion, axonal injury) • Vascular malformation • Neoplasm (primary, metastatic) o Protein-containing lesion • Colloid cyst • Craniopharyngioma • Rathke cleft cyst • Atypical epidermoid o Fat-containing • Lipoma • Dermoid • Meningioma with lipomatous differentiation o Calcification &/or ossification • Metabolic • Calcified neoplasm (e.g., oligodendroglioma) • Infection (TB, NCe) • Dural ossification o Other mineral accumulation • Liver failure o Melanin-containing lesions

o

Helpful Clues for Rare Diagnoses • Hypoxic-Ischemic Lesions o Hemorrhagic transformation in ischemic stroke (cortex> basal ganglia) o Hypotension - cortical laminar necrosis (gyriform Tl shortening) o Heat stroke - thermal injury, Tl shortening in external capsules, paraventricular thalami, cerebellum • Acute Hypertensive Encephalopathy,

PRES Gross hemorrhage rare; petechial uncommon o Typically occipital lobes • Encephalitis o Herpes encephalitis • Hemorrhagic cortical necrosis • "Sequential bilaterality" in temporal lobes highly suggestive • May also involve cingulate gyrus, subfrontal region o Other: West Nile may cause basal ganglionic necrosis, Tl shortening o

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Other Essential Information • Do T2* (GRE or SWI) scan in all patients with unexplained intracranial hemorrhage to look for additional lesions Alternative Differential Approaches • Spontaneously hyperintense intracranial lesions

Axial T1WI MR shows symmetrical foci of TI shortening In the basal ganglia in this patient with proven hypothyroidism.

=

Tl

Axial T1WI MR in this patient wilh chronic liver failure shows T 1 hyperintense lesions in the basal ganglia and posterior thalami (pulvinar).

I 5 103

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T1 HYPERINTENSE

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<9

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(Left) Axial T I WI MR shows a classic lale subacute intracerebral hematoma with TI shortening caused by extracellular melhemoglobin. (Right) Sagiual TI WI MR shows multiple hyperintense

CO

foci in the midbrain

~

8:. <= ~ CO

"CO "0

lii

and

Fornix ~ in this patient with closed head trauma and dj(fuse axonal injury.

(Left) Coronal TI WI MR shows a striking flow artifact within the 3rd and lateral ventricles If you look at adjacent brain parenchyma, you see propagation of a phase artifacl [;> across the scan indicating that this is flow related. (Right) Axial T1WI MR shows multiple hypoinlense lesions in the white matter. Note slight, hazy "rings" of subllc T7

=.

shortening

around

a

many of

the lesions presumably due to coagulative necrosis in the periphery of chronic MS plaques.

(ieft) Axial TI WI MR in patient with known metastatic renal cell carcinoma

shows multiple

foci of TI shortening gray·white

at

maller junction.

Findings are characteristic

of

metastases with subacute hemorrhage. (Right) Axial TI WI MR in elderfy

normotensive demented

I 5 104

patient with history of "multiple strokes" & clinical diagnosis of "vascular dementia II shoW's multiple T 1 hyperintense lesions in patient with both lobar & microhemorrhages

=.

PARENCHYMAL

LESION(S)

11 HYPERINTENSE

PARENCHYMAL

LESION(S)

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III

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tD

Cavernous Malformation

Neurofibromatosis

Type 1

III

(Left) Sagittal T7 WI MR in a patient with multiple cavernous

malformation

syndrome shows a typical "popcorn"·fike lesion II] along with a much smaller hyperintense focus E!lI of subacute hemorrhage. (RighI) Axial T7WI MR shows bilateral pallidal, thalamic~ and internal capsule hyperintensities ffi commonly seen in NF ,. These probably represent myelin clumping or T7 shortening caused by microcalcifications.

Tuberous Sclerosis Complex

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Acute Hypertensive Encephalopathy, PRES (Lefl) Sagittal T7 WI MR shows radial white matter lines ~ and subependymal hamartomas ~ as areas of increased signal intensity on unenhanced T7Wls prior to myelin

maturation.

Following

myelination they are best seen on FLAIR. (RighI) Axial T7WI MR shows bioccipital subacute hemorrhages ~ in patient with severe PRES. Frank ischemia/infarction,

hemorrhage are rare complications; most lesions resolve spontaneously with blood pressure normalization.

Encephalitis (Miscellaneous)

Melanoma Metastases (Left) Axial T1 WI MR shows bilateral foci of T I shortening It] in this patient with West Nile encephalitis. (Right) Axial T7 WI MR shows 3 foci of T7 shortening =::I in a patient with known melanoma. Melanin has an intrinsic short T7, but melanoma metastases often hemorrhage as well.

I 5 105

~ '"

BRAIN TUMOR IN NEWBORN/INFANT

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DIFFERENTIAL DIAGNOSIS Common • Anaplastic Astrocytoma • Teratoma • Medulloblastoma (PNET-MB) • Supratentorial PNET • Supratentorial Ependymoma • Choroid Plexus Papilloma Less Common • Subependymal Giant Cell Astrocytoma • Desmoplastic Infantile Ganglioglioma • Desmoplastic Infantile Astrocytoma • Glioblastoma Multiforme Rare but Important • Choroid Plexus Carcinoma • Atypical Teratoid-Rhabdoid Tumor • Neurocutaneous Melanosis (Mela noma/Melanocytoma) • Pineo blastoma • Brainstem Glioma, Pediatric • Medulloepithelioma

ESSENTIAL INFORMATION

I 5 106

• Sparse Ca++ '" 20% • Enhancement usual (may be late/slow) • Hemorrhage rare a Hypercellularity reflected on imaging • Hyperdense (NECT), hypointense (T2) a Medulloblastoma with extensive nodularity • Subtype with expanded lobular architecture • Grape-like enhancement • Better prognosis • Supratentorial PNET a Large complex mass • Restricts on DWI (differentiates from ependymoma) • Heterogeneous signal, enhancement • Ca++ more common than in posterior fossa PNETs • Hemorrhage, necrosis common a Hemispheric • Mean diameter 5 em • Especially newborn/infants • Minimal peritumoral edema a Suprasellar • Early neuroendocrine, visual disturbances a Pineal (pineoblastoma) • Hydrocephalus, Parinaud syndrome • Supratentorial Ependymoma a Peri/extraventricular> intraventricular • Periventricular ependymal rests • Large, bulky • Ca++ '" 50% • Variable necrosis, hemorrhage • Choroid Plexus Papilloma a CPP: Lobulated intraventricular mass • Lateral> 4th> 3rd • NECT: [so- to dense • Iso- to slightly hyperintense on T2WI • Vividly enhancing a Hydrocephalus common Helpful Clues for Less Common Diagnoses • Subependymal Giant Cell Astrocytoma a Enhancing mass near foramen of Monro a Found in tuberous sclerosis complex a Look for • Subependymal Ca++ nodules • Tubers (best on FLAIR) • Desmoplastic Infantile Ganglioglioma a DIGs often have large cyst a Cortically based enhancing tumor nodule

BRAIN TUMOR IN NEWBORN/INFANT

Enhancing adjacent pia & dura • Desmoplastic Infantile Astrocytoma o Similar to (but rarer than) DIG • Glioblastoma Multiforme o Bulky irregular enhancing tumor o Peritumoral edema, mass effect o Hemorrhage, central necrosis, cysts o t Glucose metabolism, avid FDG accumulation on PET o

Helpful Clues for Rare Diagnoses

• Choroid Plexus Carcinoma o Similar to CPP PLUS • Brain invasion • Ca++, cysts, bleed • Ependymal, subarachnoid space seeding (can be seen with both CPP, CPC) • Atypical Teratoid-Rhabdoid Tumor o PNET-MB-likePLUS • Metastases at diagnosis more common • Cysts, hemorrhage more common • Cerebellopontine angle cistern location more common • Neurocutaneous Melanosis (Melanoma/Melanocytoma) o Giant or multiple cutaneous melanocytic nevi PLUS • Melanosis: Bright Tl amygdala, cerebellum • Melanoma: Melanosis + diffuse leptomeningeal enhancement • Pineoblastoma o Large heterogeneous pineal region mass • Peripheral Ca++

Anaplastic

• Small cysts • Inhomogeneous enhancement o Invades adjacent structures • Corpus callosum, thalamus, midbrain, vermis o Hydrocephalus usual at diagnosis • Brainstem Glioma, Pediatric o Imaging appearance, prognosis vary with tumor type, location o Tectal • Pilocytic astrocytoma • Clinically indolent course (may cause obstructive hydrocephalus) • Variable enhancement/Ca++ o Focal tegmental mesencephalic • Pilocytic astrocytoma • Cyst + nodule • Surgery, radiation, or chemotherapy • Patients generally do well o Diffuse pontine glioma • Diffusely infiltrating fibrillary astrocytoma • Nonenhancing early in course • Enhancement with malignant progression • Survival generally poor • Medulloepithelioma o Rare malignant embryonal brain tumor o Young children « 5 years) o Histologic differentiation varies • Neuronal, astrocytic, ependymal, melanotic, etc. o Imaging appearance reflects variable differentiation

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Astrocytoma

Coronal CECT in this 7 month old shows obstructive hydrocephalus and a large, i"-defined midline mass SI with ring enhancement and central necrosis.

Coronal T2WI MR in same case shows mass E:I is extensively infiltrating, with bithalamic and upper

midbrain

hyperintensity

hydrocephalus

=-

with transependymal

causing

I 5

obstructive

CSF migration.

107

BRAIN TUMOR IN NEWBORN/INFANT

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Teratoma

Teratoma (Left) Axial T7WI MR in Ihis 7 day old infanl shows T7 brighl signal from fal scallered Ihroughoullhe lesion. (Right) Axial NECT in Ihe same child al 15 monlhs shows a complicaled pineal region mass consisting of fat solid lissue and calcificalion PJgI.

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a

C1l

Medulloblastoma (Left) Axial T2WI MR in a 4 monlh old infant shows intermediate

to low signal

mass that splays and encases posterior

communicating

E.1

and superior cerebellar 11Im arleries. (Right) Coronal T7 C+ MR in Ihis 10 monlh old shows grape-like nodular enhancement lID. Medul/oblaslOma wilh extensive nodularity is a PNET-MB varianllhal has somewhat betler prognosis.

(Lefl) Axial T2WI MR in a 12 week old infanl shows a mixed helerogeneily lefl lemporallobe mass. (Right) Axial T2* CRE MR shows multifocal

hemosiderin

calciFic foci ~.

I 5 108

and

(PNET-MB)

Medulloblastoma

(PNET-MB)

BRAIN TUMOR

IN NEWBORN/INFANT

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Choroid

Plexus Papilloma

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(Left) Axial T2WI MR shows coloboma 8l and temporal lobe subependymal heterotopia in a 4 day old girl with Aicardi syndrome. (RighI) Coronal T I C+ MR shows bilateral choroid plexus papillomas. The left ~ is bulky and frond-like, while the right 81 is stretched by the associated cyst.

a large cyst

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Subependymal

Giant Cell Astrocytoma (Lefl) Sagittal ultrasound shows a bulky subependymal giant cell astrocytoma 81 at the foramen

of Monro

in this

newborn with cardiac rhabdomyoma and tuberous sclerosis. There are multiple additional tubers ~ on the same image. (RighI) Coronal T7 C+ MR in a 7 month old infant shows a massive right (ronlal cystic tumor with

a

solid enhancing component that involves the medial frontal cortex and falx.

=

Desmoplastic

Infantile

Astrocytoma

Desmoplastic

Infantile

Astrocytoma (Lefl) Axial T2WI MR in a 9 month old infant shows a right temporal cystic and solid ~ tumor with surrounding edema. (RighI) Coronal T7 C+ MR in the same infant shows encasement of the right middle cerebral artery ~ by the avidly enhancing solid component 81 of the tumor.

I 5 109

BRAIN TUMOR IN NEWBORN/INFANT

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Glioblastoma

Multiforme

(Left) Axial T2WI MR in this 6 week old infant shows a markedly heterogeneous bifrontal mass lesion with hemorrhages of various ages §. There is obstruction of both foramina of Monro and enlargement of the lateral ventricular trigones. (Righi) Axial T7 C+ MR shows extensive enhancement of thislumor.

Choroid

Plexus Carcinoma

(Left) Axial T7 C+ MR in this 9 month old infant shows a large, bulky, avidly enhancing left intraventricular tumor ~ with invasion of the overlying brain ED. There are multiple intraventricular metastases ~ (Right) Anteroposterior angiography performed as a part of pre-operative embolization shows hyper vascularity ~ and multiple areas of contrast puddling ~.

Atypical Teratoid-Rhabdoid (Left) Sagittal T2WI MR in this 7 month old inFant shows hydrocephalus and a complicated solid & cystic tumor filling the 4th ventricle, supravermian cistern and extending through the tentorial incisura E!llI. (Right) Coronal T1 C+ MR in the same 7 month old shows a right frontal metastatic deposit B.

I 5 110

Tumor

BRAIN TUMOR IN NEWBORN/INFANT III

~ C-

Neurocutaneous Melanosis (Melanoma/ Melanocytoma)

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Neurocutaneous Melanosis (Melanoma/ Melanocytoma)

O:! III

(Left) 5agiltal T1WI MR

:l

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shows increased signal

OJ

intensity of the hippocampus E!l:I in this 70 month old with

~

a large cutaneous

nevus.

Pachymeningealthickening

= is present

prior to

contrast administration. (Right) Coronal T1 C+ MR

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during the same examination

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shows diffuse pachy· and leptomeningeal metastatic melanoma.

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Pineoblastoma

Pineoblastoma

(Left) Sagittal T2WI MR in a 7 month old infant shows a mass in the pineal region traversing the tentorial incisura into the supravermian

cistern. There

;s compression

of the aqueduct of 5ylvius with resultant hydrocephalus. Acute edema along the fiber tracts of the corpus callosum renders a striated pattern El (Right) Axial OWl MR in the same patient shows typical diffusion

Brainstem

Glioma,

Pediatric

restriction.

Medulloepithelioma (Left) 5agiltal T1 C+ MR in

this newborn shows massive expansion of the pons and medulla by a nonenhancing mass. (Right) 5agiual T1WI MR in a 5 day old infant shows a massive

hemorrhagic tumor replacing and expanding the upper cervical

spinal cord, the

brainslem, and the cerebellum. The tumor protrudes through the incisura and displaces the straight sinus E!l:I.

I 5 111

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BRAIN TUMOR IN CHILD> 1 YEAR

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DIFFERENTIAL DIAGNOSIS Common • Pilocytic Astrocytoma o Cerebellar JPA o Optic Pathway Glioma o Pilomyxoid Astrocytoma (Rare) • Medulloblastoma (PNET-MB) • Ependymoma • Brainstem Glioma, Pediatric • Diffuse Astrocytoma, Low Grade • Subependymal Giant Cell Astrocytoma • DNET • Craniopharyngioma less Common • Germinoma • Choroid Plexus Papilloma • Ganglioglioma • Oligodendroglioma • Neurofibromatosis Type 2 o Meningioma o Schwannoma • Pineoblastoma • Pleomorphic Xanthoastrocytoma • Anaplastic Astrocytoma • Glioblastoma Multiforme • Gliomatosis Cerebri • Supratentorial PNET • Teratoma Rare but Important • Astroblastoma • Choroid Plexus Carcinoma • Atypical Teratoid-Rhabdoid Tumor • Primary CNS Sarcoma • Metastases o Metastases, Skull and Meningeal o Metastases, Parenchymal o Leukemia o Neuroblastoma, Metastatic o Neurocutaneous Melanosis (Melanoma, Melanocytoma) • Central Neurocytoma • Dysplastic Cerebellar Gangliocytoma

ESSENTIAL INFORMATION

I 5 112

Key Differential Diagnosis Issues • Diffusion weighted imaging helpful • All of the following restrict on DWI o PNET-MB o Pineoblastoma (pineal PNET)

Atypical teratoid-rhabdoid tumor (ATRT) o Germinoma o Epidermoid • May present with hemorrhage into tumor o Primary CNS sarcoma o Supratentorial PNET o Neuroblastoma metastatic to brain tissue o Pilomyxoid variant of pilocytic astrocytoma o

Helpful Clues for Common Diagnoses • Pilocytic Astrocytoma o Low density NECT o High signal T2 • Medulloblastoma (PNET-MB) o Hyperdense 4th ventricle (V) mass on NECT o Restricts on DWI • Ependymoma o 60% posterior fossa • "Plastic" tumor in 4th ventricle, extrudes through foramina o 40% supratentorial • Mixed cystic, solid mass with Ca++ • Brainstem Glioma, Pediatric o Location predicts pathology, prognosis • Infiltrating pontine glioma worst • Diffuse Astrocytoma, Low Grade o Hemispheres, thalami (can be bithalamic), tectum, brainstem (pons, medulla) • 50% of brainstem "gliomas" are low grade, diffusely infiltrating astrocytomas o Poorly marginated o Hypo- on Tl WI, hyperintense on T2WI o No enhancement • Subependymal Giant Cell Astrocytoma o Location at foramina of Monro typical o Look for cortical/subcortical tubers o Look for subependymal nodules • DNET o Almost all in patients < 20 years o Chronic epilepsy o "Bubbly appearing" cortically based mass o Ring sign on FLAIR • Craniopharyngioma o Nearly half of pediatric suprasellar masses o 90% Ca++/cystic/enhance Helpful Clues for less Common Diagnoses • Germinoma o Suprasellar + pineal masses together best clue o Early ependymal infiltration

BRAIN TUMOR IN CHILD> 1 YEAR • Choroid Plexus Papilloma o Densely enhancing o Cotyledon- or frond-like surface • Neurofibromatosis Type 2 o If multiple schwannomas, think NF2+ o Look for "hidden", dural-based meningiomas with C+ • Pineoblastoma o Restricts on DWI o Look for CSF spread (ventricles, ependyma) • Pleomorphic Xanthoastrocytoma o Cortically based tumor (temporal lobe most common site) o Dural reaction ( "tail") common o Enhancing ill-defined mass plus cyst • Anaplastic Astrocytoma o Diffusely infiltrating o Classic do not enhance • Glioblastoma MuItiforme o Typically arises from lower grade astrocytoma • Gliomatosis Cerebri o Less likely to enhance o More likely bilateral o More likely to spread across callosal tracts • Supratentorial PNET o Infant with large, bulky, complex hemispheric mass o Ca++, hemorrhage, necrosis common o Peritumoral edema sparse/absent • Teratoma o Neonate with large bulky midline mass o Ca++, soft tissue, cysts, fat

Cerebellar

Helpful Clues for Rare Diagnoses • Astroblastoma o Large, hemispheric o Well-circumscribed o "Bubbly" solid and cystic • Choroid Plexus Carcinoma o Similar to CPP • Invades ependymal surface & brain • Less homogeneous than CPP • Atypical Teratoid-Rhabdoid Tumor o Heterogeneous intracranial mass in infant o 50% infra tentorial, early CSF spread • Metastases o Pial, leptomeningeal • PNET • Ependymoma • Anaplastic astrocytoma • Germinoma • Choroid plexus carcinoma o Falx • Leukemia involves both sides of the falx o Bone & dura: Neuroblastoma> leukemia • CT: Bone spiculation, "hair on end" • MR: Bone expanded and marrow replaced • Central Neurocytoma o "Bubbly" lobulated mass in body of lateral ventricle • Dysplastic Cerebellar GangIiocytoma o Look for evidence of Cowden disease o Striated cerebellum • Enlarged low signal cerebellar folia

Cerebellar

JPA

Axial NEG shows typical midline cystic tumor with large low density mural nodule There is hydrocephalus with interstitialedema.

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JPA

Axial T2WI MR shows the nodule to be high signal intensity, a clue to the high nuclear-to-cytoplasm ratio in cerebellarIPAtumors.

I 5 113

BRAIN TUMOR IN CHILD>

1 YEAR

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Optic Pathway Glioma

Pilomyxoid

Astrocytoma

(Rare)

(Left) Axial T2WI MR shows poorly marginated hyperintensity =:I that extends posteriorly from optic chiasm/hypothalamus along both optic radiations. (Right) Axial T2WI MR shows a large, hyperintense, well-circumscribed mass. It arises from the hypothalamic region and demonstrates no edema of adjacent structures.

Medulloblastoma

(PNET-MB)

Medulloblastoma

(PNET-MB)

(Left) Axial T2WI MR shows a Jow signal midline tumor. There is an associated cyst =:1_ (Right) Axial OWl MR shows diffusion restriction within the tumor nodule, an excellent clue to the aggressive nature of the lesion.

Brainstem (Left) Sagittal T2WI MR shows a large, heterogeneous, low signal mass that widens the tegmenta-cerebellar angle and extends through the inferior recesses of the 4th ventricle. There is extension into the upper cervical spinal canal =:1_ (Right) Sagittal T2WI MR shows diffuse expansion of the pons and medulla

glioma_

I 5 114

due to an infiltrating

Glioma, Pediatric

BRAIN TUMOR IN CHILD>

en ,.-

1 YEAR

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Giant Cell Astrocytoma

ll>

DNET (Lcfl) Coronal T1 C+ MR shows bilateral, asymmetric enhancing lesions at the foramina location

of Monro.

The

is characteristic

for

subcpendymal giant cell astrocytoma. The child also had skin and other brain lesions typical of tuberous sclerosis. (RighI) Coronal FLAIR MR in a child with

tAl ., III

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seizures shows an

=-

insular·based

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lesion with a

partial bright ring the ONET FLAIR ring sign.

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III

Germinoma (Lcfl) Sagittal T1WI MR shows a suprasellar collection of cysts of many signal intensities. One!:] is very high signal intensity, likely due to protein; another extends behind the clivus 81; and the remainder herniate

into Jrd ventricle.

Calcification 1:1:1 is noted in the solid component above the dorsum sella. (RighI) Sagittal T1 C+ MR shows a medium-sized pineal mass with central necrosis 1m. There is a very small enhancing

infundibular

Choroid

mass in the

recess

e=.

Plexus Papilloma (Lefl) Coronal T1 C+ MR shows a large enhancing mass within the right lateral venlricle. The surface is frond-like, and there is no brain invasion. appearance

The

is typical for a

choroid plexus papilloma. (RighI) Axial TI C+ MR shows a cystic and solid thalamic mass. This lesion was heavily calcified on NECT (not shown).

I 5 115

BRAIN TUMOR IN CHILD>

ro ~

1 YEAR

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Neurofibromatosis

Type 2

(Left) Coronal T2WI MR shows multiple dural-based meningiomas ED at the vertex. There are a/50 bilateral, asymmetric, vestibular schwannomas ~ in this teen with NF2. (Right) Sagittal T2WI MR shows a low signal pineal mass that obstructs the aqueduct. This lesion was dense on NEeT and restricted on DWI.

(Left) Coronal T1 C+ MR shows a cortically based temporal lobe tumor. It is ill-defined, invades adjacent brain tissue, enhances, and contains

a rim-enhancing

cyst ~. (Right) Axial T2WI MR shows bithalamic involvement by

homogeneous

lUmor,

did not enhance

which

on T I C+

image (not shown).

Supratentorial (Left) Coronal T1 WI MR shows marked expansion of the left temporal lobe by a hemorrhagic ED mass. (Right) Sagittal T2WI MR shows a mixed solid, cystic, and calcified

pineal

region

mass Blthat obstructs the aqueduct of Sylvius. This teenaged patient presented with Parinaud

phenomenon.

There is acute edema involving the septal-callosal interface =:II.

I 5 116

PNET

Pineo blastoma

BRAIN TUMOR IN CHILD>

Choroid

Plexus Carcinoma

1 YEAR

Atypical Teratoid-Rhabdoid

Tumor (Left) Axial T1 C+ MR shows a large heterogeneously enhancing trigonal mass with brain invasion and

ependymal spread 811. (RighI) Axial T2WI MR shows a mixed signal mass obstructing both the right 811 and left foramina of Monro.

Gl

ct> ::J ct> ~ OJ

Atypical Teratoid-Rhabdoid

Tumor (Left) Axial OWl MR in the same patient shows extensive diffusion restriction in the left frontal ATRT. (RighI) Axial CECT in metastatic PNET-MB shows "comb-like" enhancement of the interfoliate sulci ~ Note moderately enlarged lateral ventricles 1:1 caused by

extraventricular obstructive hydrocephalus

from diffuse

cisternal metastases.

leukemia

Neuroblastoma,

Metastatic (Lefl) Axial T1 C+ FS MR in a child with ALL shows involvement of the posterior and anterior 811 falx by densely enhancing tissue. Both sides of the falx are involved ventrally. (RighI) Coronal FLAIR MR shows expansion of the lesser wing of sphenoid by neuroblastoma. There is an

=

additional

calvarial

and

dural-based focus at the vertex EJ.

I 5 117

EPILEPSY, GENERAL

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Common • Acquired Causes o Trauma o Remote Stroke o Remote Infection o Neoplasms o Mesial Temporal Sclerosis (MTS) o Vascular Malformations o Toxic/Metabolic Insult, NOS o Drug Abuse • Heterotopic Gray Matter • Perisylvian Dysplasia • Schizencephaly • Septo-Optic Dysplasia • Tuberous Sclerosis Complex (TSC) • Focal Cortical Dysplasia, Taylor Type (Balloon Cell Dysplasia) • Focal Cortical Dysplasia • Pachygyria-Polymicrogyria • Lissencephaly Type 1 • Band Heterotopia • Hemimegalencephaly Less Common • Neuronal & Mixed Neuronal-Glial Tumors o DNET o Ganglioglioma • Pleomorphic Xanthoastrocytoma

•

•

•

•

Rare but Important • Sturge-Weber Syndrome • Status Epilepticus

I 5 118

MTS: Small, hyperintense hippocampus associated with temporal lobe epilepsy o Causative vascular malformations include AVM & cavernous malformations o Toxic-metabolic & drug abuse patients may present with seizures Heterotopic Gray Matter o Gray matter (GM) nodules, follow GM signal on all MR sequences o Subependymal most common location o Can be found incidentally in patients without seizures Perisylvian Dysplasia o Common site for cortical dysplasia o Typically bilateral o ± Septo-optic dysplasia, schizencephaly Schizencephaly o CSF cleft extending to ventricular ependyma, GM-lined o Outpouching or "dimpling" of lateral ventricular contour "points" to cleft o Two morphologic varieties • Closed lip: GM ependymal seams touch • Open lip: GM seams separated by cleft o May be unilateral or bilateral o Absent septum pellucidum common o Associated with septo-optic dysplasia Septo-Optic Dysplasia o Some consider mildest form of holoprosencephaly o Septum pellucidum absence + optic nerve hypoplasia, ± pituitary dysfunction o Common associated malformations: Schizencephaly, perisylvian dysplasia Tuberous Sclerosis Complex (TSC) o T2 hyperintense cortical/subcortical tubers o Subependymal nodules follow white matter (WM) signal until calcified o 10-15% develop giant cell astrocytoma Focal Cortical Dysplasia, Taylor Type (Balloon Cell Dysplasia) o Imaging & histology = tubers in TSC • Histology shows "balloon cell" dysplasia o Solitary dysplasia; lack other TSC features o T2 hyperintense "comet tail" from cortex to ventricle; best seen on FLAIR> T2 > T1 Focal Cortical Dysplasia o Thickening &/or nodular cortex o Blurred gray-white junction Pachygyria-Polymicrogyria o Pachygyria: Thick, smooth cortex o

DIFFERENTIAL DIAGNOSIS

ESSENTIAL INFORMATION

•

Key Differential Diagnosis Issues • Generalized seizure disorders usually nonlocalizing • Partial complex (focal) epilepsy usually due to focal structural abnormality (i.e., MTS) • High-resolution MR necessary to fully evaluate epilepsy

•

Helpful Clues for Common Diagnoses • Acquired Causes o Trauma is most common cause in adults o Trauma, remote stroke, or infection results in encephalomalacia &/or gliosis, which may cause epilepsy o Benign, malignant tumors

•

•

,... C/)

EPILEPSY, GENERAL

c:

Polymicrogyria: Small, "pebbly", cobblestone or micronodular appearing gyri (cortical dysplasia) • Lissencephaly Type 1 o "Smooth" brain lacking normal gyral infolding; thick cortex o Spectral continuum with po Iymicrogyria -pach ygyr ia • Band Heterotopia o Most genetic; X-linked inheritance o Most (90%) are female • Males severely affected, rare survival o Band of incompletely migrated GM between cortex & ventricle (double cortex) o GM band size inversely proportional to overlying cortex thickness • Hemimegalencephaly o Unilateral hemispheric overgrowth o Dysplastic enlarged ipsilateral ventricle o Overlying skull & soft tissues overgrown o

Helpful Clues for Less Common Diagnoses • DNET o Discrete T2 hyperintense "bubbly" cortical mass, low grade neuronal neoplasm o Associated cortical dysplasia common o Medial temporal lobe most common • Ganglioglioma o Cystic/solid enhancing, cortically based mass, mixed neuronal-glial tumor o Temporal lobe most common site o Associated cortical dysplasia common • Pleomorphic Xanthoastrocytoma o Cyst + enhancing nodule classic

Mesial Temporal Sclerosis (MTS)

Coronal FlAIR MR shows high signal in the right hippocampus 1:2 related to this paUent's MTS. The primary MR features are T2 hyperintense signal, atrophy of the hippocampus, & loss of internal architecture.

o o

Well-circumscribed, no surrounding edema Involvement of adjacent meninges typical

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Helpful Clues for Rare Diagnoses • Sturge-Weber Syndrome o Malformation of cortical & pial veins o Clinical diagnosis by trigeminal distribution facial "port-wine" stain o Earliest intracranial finding = ipsilateral enlarged choroid plexus o Later = ipsilateral hemiatrophy • Status Epilepticus o Focal cortical (& subcortical) edema, T2 hyperintense • Varied cortical enhancement • Usually DWI & FLAIR bright o Persistent seizures, often 2: 24 hours o May show hyperperfusion: High CBV & CBF, delayed MTT o Most resolve in days-weeks o Long term atrophy may result

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Other Essential Information • "New onset seizures" require routine brain MR with & without contrast o Rule out acute lesions: Hemorrhage, tumor, infection, & stroke • "Epilepsy" high resolution MR evaluation o High resolution Tl/T2 (3D techniques at 1 mm slices preferred) through entire brain o IR techniques improve gray-white matter contrast (STIR, FLAIR, & Tl FLAIR) o High field strength (3T) preferred

Mesial Temporal Sclerosis (MTS)

Coronal T1WI MR shows typical decreased parenchymal volume 1:2 of U,e hippocampus in MTS.

I 5

Internal architecture remains preserved in this case. Mild enlargement of the adjacenllemporal

horn is common.

119

EPILEPSY, GENERAL

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Vascular Malformations

Vascular Malformations

Heterotopic Gray Matter

Heterotopic Gray Matter

(Left) Axial Tl WI MR shows hyperintensity related to recent hemorrhage in a cavernous malformation

=-

Seizures are often the presenting

symptom

for

vascular lesions such as a cavernoma or AVM. (Right) Axial T2' GRE MR shows susceptibility artifact in this cavernous malformation It] with recent hemorrhage. GRE/SWI MR is helpful to search for additional lesions that may be occult on other

sequences.

(Left) Axial Tl WI MR shows mu/tiFocal gray maller

nodules lining both lateral ventricles Note a/50 heterotopic gray matter within the left frontal lobe white matter PlB.

=.

I feterotopic

gray matter

follows gray matter signal on all MR sequences & does 110t enhance. (Right) Coronal T2WI MR shows multiple foci of cortical gray matter lining the ependymal margin of both lateral ventricles These may be associated with seizures or may be asymptomatic.

=.

(Left) Sagittal Tl WI MR shows multifocal dysplastic cortex Perisylvian involvement (perisylvian dysplasia) BlI is common. Such focal abnormalities are found in many patients with partial complex epilepsy. (Right) Coronal T2WI MR shows symmetric frontal and opercular bilateral polymicrogyria also known as cortical dysplasia. Note additional bands of laminar heterotopic gray matterE:l.

=.

=-

I 5 120

EPILEPSY, GENERAL

,.c: CIl

(Left) Axial T1 WI MR shows a classically located perisylvian open lip schizencephaly, with a wide CSF cleft Ell lined with gray matter The cleft margins do not lOuch in open-lip schizencephaly. (Right) Axial T2WI MR shows a closed-lip schizencephaly lined by dysplastic gray matter

=.

=.

Note the characteristic

ventricular outpouching

~

Flow voids from embryonic

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vessels lay adjacent to the lateral margin of the schizencephalic cleft P.::l.

(Left) Coronal T2WI MR shows seplO-optic dysplasia, with small optic chiasm 8absent septum pellucidum 68 Note that the sella is also small These patients

=.

frequently also have pituitary hypofunction. (Right) Coronal T2WI MR shows right perisylvian polymicrogyria in this seplO-optic dysplasia patient, a common association.

=

However. schizencephaly is nearly always associated with polymicrogyria, adjacent 10 the schizencephalic cleft.

Tuberous Sclerosis

Complex

(TSC)

Tuberous Sclerosis

Complex

(TSC) (Left) Coronal FLAIR MR shows numerous subcortical hyperinlensilies consistent with tubers in this TSC patient Several subependymal nodules (SEN) Ell are also present. Before they calcify, SEN

=

follow

white matter signal.

(Right) Axial T1 C+ MR shows a subependymal giant cell astrocytoma seen in 10-/5% of patients with TSC. Note the associated ventriculomegaly. Multifocal subcortical tubers P1tJ are seen in the left hemisphere.

=..

I 5 121

EPILEPSY, GENERAL

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Focal Cortical Dysplasia, Taylor Type (Balloon Cell Dysplasia)

Focal Cortical Dysplasia, Taylor Type (Balloon Cell Dysplasia)

(Left) Coronal T2WI MR shows classic findings in Taylor dysplasia, demonstrating juxtacorlical high signal with a thin "seam' of high signal E!ilI tracking along the expected course of the radial glial fibers to the subependymal margin. FLAIR is often more sensitive to these dysplasias. (Rig"') Coronal FLAIR MR shows a single focus of mild gyral expansion ~ and classic thin high signal seam extending to the ventricle

=

= E!ilI.

Focal Cortical

Dysplasia

(Left) Coronal T7WI MR shows thickened, ill-defined frontal cortex with mild blurring of the gray-white junctions related to [ocal cortical dysplasia. Such findings should be confirmed

=

with multipJanar

imaging

or

isovoxel reconstructions. (Right) Sagittal T7 WI MR shows small disorganized perisylvian gyri with a cobblestone appearance,

=

characteristic

for

polymicrogyria. Other areas of cortex appear thickened E!ilI & indistinct related to pachygyria.

Band Heterotopia (Left) Axial T2WI MR shows a thin band of gray matter in the deep white matter of both hemispheres in a 6

=

month

old. Some consider

band heterotopia to be in the gray matter heterotopia spectrum. (Right) Coronal T2WI MR shows decreased sulcalion,

primitive

a

=

I 5 122

sy/vian

fissures & thick bands of incompletely migrated cortex consistent with band heterotopia ("double cortex"). Note thickness of overlying cortex is inversely proportional to band heterotopia.

Band Heterotopia

EPILEPSY, GENERAL III

::::l

C-

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III

(Left) Coronal T1WI MR show an enlarged right hemisphere and ventricle compared to the left. Note ipsilateral dysplastic appearing gray matter I:] in this hemimegalencephaly patient. (Right) Coronal T1 WI MR shows a nearly cystic-appearing mass in the mesial right temporal lobe 81. This was a proven DNET (dysembryoplastic neuroepithelial tumor), a neuronal tumor commonly associated with dysplastic

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cortex.

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Xanthoastrocytoma (Left) Axial T1 C+ MR shows a circumscribed cystic & solid mass in the anterior temporal lobe 1:]. This well-differentiated neuronal-glial tumor is the most common tumor to cause temporal lobe epilepsy. (Right) Axial T1 C+ MR shows a cystic and solid enhancing temporal mass 8l typical of pleomorphic xanthoastrocytoma (PXA), recurrent in this case. PXAs often extend to the adjacent meninges & have a "dural tail".

Sturge-Weber

Syndrome (Left) Coronal T1 C+ MR shows right hemiatrophy, pial enhancement, and angiomatosis of CSF spaces. This congenital malformation has failure of

=

cortical venous development that leads to progressive venous occlusion and ischemia. (Right) Coronal FLAIR MR shows marked hyperintensity involving temporal cortex and adjacent subcortical

while matter

=

in a patient with persistent status epilepticus. These changes resolved slowly over the following weeks.

I 5 123

SECTION 6 Supratentorial Brain Parenchyma Anatomically Based Differentials Asymmetric Cerebral Hemispheres Thick Cortex Thin Cortex Focal Cortical Mass Cortical Hyperintensity T2/FLAIR Cortical Enhancement Solitary White Matter Lesion Confluent White Matter Lesions Thin Corpus Callosum Abnormal Shape/Configuration of Corpus Callosum Corpus Callosum Holes Corpus Callosum Lesion without Mass Effect Corpus Callosum Mass Corpus Callosum Splenium Lesion Basal Ganglia Calcification T1 Hyperintense Basal Ganglia T2 Hyperintense Basal Ganglia Enlarged Perivascular Spaces Perivascular Space Enhancing Lesions Bilateral Basal Ganglia Lesions Putamen Lesion(s) Globus Pallidus Lesion(s) Unilateral Thalamic Lesion Bithalamic Lesions "Pulvinar Sign" Tectal (Quadrigeminal Plate) Lesion Midbrain Lesion

1-6-2 1-6-8 1-6-14 1-6-20 1-6-24 1-6-28 1-6-30 1-6-34 1-6-40 1-6-46 1-6-52 1-6-54 1-6-56 1-6-58 1-6-62 1-6-66 1-6-70 1-6-74 1-6-76 1-6-80 1-6-84 1-6-86 1-6-90 1-6-92 1-6-96 1-6-98 1-6-100

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DIFFERENTIAL DIAGNOSIS Common • ormal Variant • Encephalomalacia, General o Post-Ischemic Encephalomalacia o Post-Traumatic Encephalomalacia o Post-Inflammatory Encephalomalacia • Contusion/Traumatic Cerebral Edema • Cerebral Ischemia-Infarction, Acute • Cerebral Infarction, Chronic • Alzheimer Dementia • Multi-Infarct Dementia • CMV, Congenital • Frontotemporal Dementia • Dyke-Davidoff-Masson less Common • Hypoxic Ischemic Encephalopathy • Encephalitis • Sturge-Weber Syndrome • Plagiocephaly • MELAS • Hemimegalencephaly of Tuberous Sclerosis Rare but Important • Hemimegalencephaly (Sporadic or Familial) • Pachygyria-Polymicrogyria • Gliomatosis Cerebri • Epidermal Nevus Syndrome • Schizencephaly • Encephalocraniocutaneous Lipomatosis • Proteus Syndrome

•

•

•

•

•

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Differential diagnosis list is vast and could logically be subdivided as follows o One hemisphere larger than the other o One hemisphere smaller than the other

I 6 2

Helpful Clues for Common Diagnoses • Normal Variant o Minor asymmetry of otherwise normal appearing density/intensity parenchyma o Substantial individual diversity of left-right gyral cerebral cortex asymmetries o Cerebral asymmetry patterns are not universal & show variation based on origin • Encephalomalacia, General o All etiologies appear as CSF replacing destroyed parenchyma due to

•

•

• Post-ischemic loss of tissue following parenchymal hypoxic cell death • Post-traumatic loss from parenchymal irreversible traumatic insult • Post-inflammatory loss by irreversibly injured tissue o Post-Traumatic Encephalomalacia • Parenchymal loss replaced by CSF • Occur in characteristic locations where brain is adjacent to bony protuberance or dural fold Contusion/Traumatic Cerebral Edema o Patchy superficial hemorrhages within edematous background, loss of gray-white distinction o Swelling with loss of sulci, fissures, & cisterns Cerebral Ischemia-Infarction, Acute o Early cortical swelling in defined vascular distribution(s) o DWI restriction with correlating ADC map Cerebral Infarction, Chronic o Volume loss with gliosis along margins o Loss in a defined vascular distribution Alzheimer Dementia o Parietal & temporal cortical atrophy with disproportionate hippocampal volume loss o Often affects brain asymmetrically Multi-Infarct Dementia o Multifocal infarcts of gray matter, white matter, basal ganglia, pons o Usually bilateral, but may be unilateral CMV, Congenital o Microcephaly, cerebral calcification, cortical gyral abnormalities, cerebellar hypoplasia, & myelin delay or destruction o Gestational age at time of infection determines pattern of CNS injury Frontotemporal Dementia o Caused by focal cortical atrophy involving frontal &/or temporal lobes o Worse atrophy of dominant hemisphere Dyke-Davidoff-Masson o Cerebral hemiatrophy with ipsilateral hypertrophy of the skull and sinuses o Caused by an intrauterine or perinatal carotid artery infarction

Helpful Clues for less Common Diagnoses • Hypoxic Ischemic Encephalopathy o Acquired neonatal condition generally attributed to cerebral hypoperfusion

ASYMMETRIC

CEREBRAL

HEMISPHERES

en ""

C

•

•

•

•

•

o Several brain injury patterns attributed to differing clinical variables Encephalitis o Abnormal T2 hyperintensity of gray matter ± white matter, or deep gray nuclei o Diffuse brain parenchymal inflammation caused by a variety of pathogens, most commonly viruses Sturge- Weber Syndrome o Cortical Ca++, atrophy, and enlarged ipsilateral choroid plexus o Unilateral 80%, bilateral 20%; occipital> parietal> frontal/temporal lobes > diencephalon/midbrain> cerebellum Plagiocephaly oCT: Osseous asymmetry with thickened & sclerotic suture margins o Premature unilateral closure of coronal &/or lambdoidal sutures MELAS o Stroke-like cortical lesions crossing typical vascular territories o Acute - gyriform swelling; chronic atrophy Hemimegalencephaly of Tuberous Sclerosis o Unilateral lobar/hemispheric overgrowth o Look for other markers of TSC (e.g., subependymal nodules)

Helpful Clues for Rare Diagnoses • Hemimegalencephaly (Sporadic or Familial) o Hamartomatous overgrowth of hemisphere

•

•

•

• •

•

o Defect of cellular organization, neuronal migration Pachygyria-Polymicrogyria o Findings range from incomplete lissencephaly to excessively small & prominent gyral convolutions o Disorder of neuronal migration Gliomatosis Cerebri o T2 hyperintense infiltrating mass with enlargement of involved hemisphere o Typically hemispheric white matter involvement, involves cortex in 19% Epidermal Nevus Syndrome o Hemimegalencephaly is most common CNS abnormality o Also migration abnormalities, vascular malformations, corpus callosal agenesis, Dandy-Walker, myelomeningocele, Chiari malformations, & tumors Schizencephaly o Transmantle gray matter lined clefts o "Closed-lip" (small) or "open-lip" (large) Encephalocraniocutaneous Lipomatosis o Hemispheric atrophy, ventriculomegaly with ipsilateral alopecia overlying a scalp lipoma o Hydrocephalus is frequently present Proteus Syndrome o Complex hamartomatous disorder involving half the body o CNS: Hemimegalencephaly, subependymal calcified nodules, & periventricular cysts

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Normal Variant

I Axial T2WI MR shows normal asymmetry, especially involving the left temporal/occipital lobes =:I as compared to the right. in this paUent with headache and a normal MR.

Axial T2WI MR shows typical MCA distribuUon chronic infarct as encephalomalacia WiUl gliotic hyperintense margins !:ll. Adjacent sulci & ventricle SI are prominent from volume loss.

6 3

ASYMMETRIC

Post- Traumatic

CEREBRAL

HEMISPHERES

Encephalomalacia

Post-Inflammatory

Encephalomalacia

(Left) Axial NECT demonstrates posHraumalic encephalomalacia of bilaleral reclus gyri ~ & lefl temporal tip ~ in characteristic locations adjaCenllO bony surfaces. (Right) Axial Tl C+ MR shows extensive cavitation of bilateral hemispheric white matter with extreme volume los5 and cavity retraction bilalerally, right more lhan left, all sequelae from Citrobacler meningitis.

=

Contusion/Traumatic

Cerebral

Edema

Cerebral

Ischemia-Infarction,

(Left) Axial NECT shows diffuse hypodensity, decreased gray-white matter differentiation, & diffuse sulcal effacement in the righl hemisphere. Note a/50 traumatic subarachnoid hemorrhage subdural hemorrhage mass effect, & leftward midline shift. (Right) Axial CECT shows a classic wedge-shaped acute infarction with hypodensity loss of gray-while interface, & insular ribbon, as well as effacemenl of sulci & ipsilateral ventricle.

=-=-

=-

Cerebral (Left) Axial NECT shows a right lemporallobe infarcl as a wedge-shaped encephalomalacic brain with low density margins of gliOlic brain. Associated dystrophic calcification is

=

.=

rare. Ipsilateral

I 6 4

ventricle

;s

mildly enlarged from volume loss 8:1. (Right) Axial FLAIR MR shows typical findings of Alzheimer dementia with more pronounced atrophy involving the temporal lobes, left more than righI, besl evidenced as asymmetry of the cortices & sylvian fjssures

8:1.

Infarction,

Chronic

Alzheimer

Dementia

Acute

ASYMMETRIC

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CEREBRAL HEMISPHERES

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III

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Multi-Infarct Dementia

III

CMV, Congenital (Left) Axial NECT shows the classic appearance of multi-infarct

dementia

perivenlricular

with

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while matter

hypodensity =:I as well as multiple bilateral MCA distribution cortical infarcts ~. (Right) Axial NECT shows bilateral perivenlricular calcifications =:I and ventriculomegaly right more involved than left.

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Dyke-Davidoff-Masson (Left) Axial NEeT demonstrates a classic CT appearance of frontotemporal

dementia,

also known as Pick disease, with bilateral frontal and temporal lobe atrophy right side more involved than left. (Right) Axial NEeT demonstrates left-sided hemispheric atrophy with ipsilateral ventricular enlargement =:I and osseous hypertrophy with hyper-pneumatization of the

=-

sinuses~.

(Left) Axial T2WI MR demonstrates asymmetric perivenlricular infarction

white matter

and loss

from

HIE. (Right) Coronal T1 C+ MR reveals a typical MR case of viral encephalitis =:I without

significant

enhancement,

mimicking

low grade glioma

a

or infarct.

I 6 5

ASYMMETRIC

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HEMISPHERES

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Syndrome

(Left) Coronal TI C+ MR demonstrates right hemiatrophy with extensive

unilateral

pial enhancement

=.

right coronal

synostosis resulting in asymmetry. Craniosynostosis of one suture leads to excessive growth of unfused sutures and significant

plagiocephaly.

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Hemimegalencephaly of Tuberous Sclerosis

MElAS (Left) Axial T2WI MR shows right temporal lobe cortical hyperintensily and swelling with relative sparing of underlying while mailer =::I. Under/ying white matter sparing, MRS is helpful in making distinction. (Right) Axial NECT reveals Ihal the en/ire lefl frontal lobe is replaced by a hamartomatous overgrowth of disordered and partially calcified

neural tissue

=.

Hislologically Ihese lesions share characteristics with hemimegalencephalyand are uncommon.

Hemimegalencephaly Familial) (Left) Axial T2WI MR enlargement of leFt cerebral hemisphere with left Fornix overgrowth. In this patient, there is normal signal inlensily of gray and white matter despile the asymmetry. (Right) Axial FLAIR MR demonstrates cerebral asymmetry resulting confirms

=

from right perisylvian

dysplasia

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(Sporadic or

ASYMMETRIC

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into the insula,

basal ganglia, and internal capsule !:l as well as mild mass effect upon lhe right lateral ventricle. (Right) Axial T2WI MR shows left hemimegalencephaly Sl diffuse gyralthickening & hyperintense demyelination !:l ipsilaleral to facial hemihyperlrophy.

=-

Encephalocraniocutaneous

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(Left) Axial T2WI MR shows hyperinlensily involving bOlh the cortex and subcortical while mailer of the right tempora1- parietal, and occipital lobes NOle

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Lipomatosis (Left) Axial T2WI MR shows a small dimple on the lateral wall of lhe lateral ventricle "poin!ing" to the site of the fused pial-ependymal seam The aperlUre of the clefl is lined by helerolopic gray mailer 81. (Right) Axial NECT demonstrates unilateral, lefl-sided hemispheric atrophy wilh associated enlargement of the left lateral ventricle and subarachnoid space over the hemisphere An overlying

=.

scalp lipoma is not shown.

Proteus Syndrome

Proteus Syndrome (Left) Axial low field T2WI MR shows righl hemimegalencephaly in a 6 year old girl with normal

karyotype and PrOleus syndrome. Note mild ipsilateral venlriculomegaly 81 and prominenl soft !issues (Right) Coronal low field T1WI MR shows right hemimegalencephaly in lhe same pa!ien!. Note mild ipsilateral ventriculomegaly 81 and prominent skull/sofl

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tissues

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DIFFERENTIAL DIAGNOSIS Common • Encephalitis • Herpes Encephalitis Less Common • Hypomyelination (Pseudo Thick Cortex) • Tuberous Sclerosis Complex • Taylor Cortical Dysplasia • Pachygyria-Polymicrogyria • Hemimegalencephaly • Lissencephaly Type 1 Rare but Important • eoplasms Associated with Cortical Dysplasia o DNET o Ganglioglioma o Dysplastic Cerebellar Gangliocytoma • Glioblastoma Multiforme • Gliomatosis Cerebri • Meningioangiomatosis • Congenital Muscular Dystrophy

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • EXCLUDES transient (e.g., MELAS, cortical edema from stroke/seizure, etc.) • Is cortex thick on both Tl and T2W sequences? • Does cortex follow gray matter signal intensity (malformations)? or is it hyperintense (infection, neoplasm)? • Is thickened cortex very focal (think neoplasm)? or more generalized (malformation) ?

I 6 8

Helpful Clues for Common Diagnoses • Encephalitis o Commonly identified agents: Enterovirus, HSVl, Mycoplasma pneumonia, Epstein-Barr, HHV-6, influenza o Etiology not found in '" 50% o Hyperintense on T2WI, FLAIR o Thickened, hyperintense temporal lobe/insular cortex • Herpes Encephalitis o Often bilateral, asymmetric o Look for cingulate gyrus, subfrontal cortex involvement o Restricts strongly on OWl

o

Enhancement,

hemorrhage

follow

Helpful Clues for Less Common Diagnoses • Hypomyelination (Pseudo Thick Cortex) o Diminished/absent white matter (WM) myelination for age • Lacks peripheral "arborization" of white matter o Can be primary or secondary • Primary hypomyelination (e.g., Pelizaeus-Merzbacher ) • Secondary (prematurity, malnutrition) o Imaging • "Pseudo" thick cortex appearance • Poor gray-white differentiation on Tl WI in children> 1 year • Poor gray-white differentiation on T2WI in children> 2 years • Small brain with thin corpus callosum • Tuberous Sclerosis Complex o Flattened, thickened gyri with "blurred" GM/WM border o Can be calcified, involve entire mantle o Look for subcortical WM hyperintensities, subependymal nodules • Taylor Cortical Dysplasia o Also known as focal cortical dysplasia (FCD) type 2A/B o "Balloon cell" dysplasia o Malformation of cortical development o Refractory focal epilepsy o Thickened cortex with Tl hyperintensity, T2 hypointensity in infancy • Rare Ca++ o Lesion conspicuity decreases with WM maturation • Pachygyria-Polymicrogyria o Polymicrogyria ...•excessively small, prominent convolutions ("gyri on gyri") o Pachygyria (sometimes called incomplete lissencephaly) ...•thickened, dysplastic cortex o Both cause appearance of "thick cortex" on imaging o Density/signal intensity of affected cortex same as normal gray matter • Hemimegalencephaly o Hamartomatous overgrowth of part/all of a hemisphere o Enlarged hemisphere with thickened, often dysplastic cortex

CIl

THICK CORTEX

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C

Ipsilateral ventricle often enlarged, abnormally shaped o White matter often overgrows, is hypermyelinated • Lissencephaly Type 1 o Most severe type (complete agyria) is Miller-Dieker syndrome o Thick, multilayered cortex o "Hour glass" configuration with shallow sylvian fissures in severe cases o

Helpful Clues for Rare Diagnoses • DNET o Young patient, longstanding seizures o Well-demarcated "bubbly" intracortical mass o Often associated with adjacent cortical dysplasia • Ganglioglioma o Child/young adult, seizures o Superficial hemispheres, temporal lobe o Cyst with nodule, ± Ca++, enhancement typical o Solid ganglioglioma can resemble Taylor cortical dysplasia (TCD does not enhance) • Dysplastic Cerebellar Gangliocytoma o Thickening, overgrowth of cerebellar folia o Gyriform "layered" or "striated" pattern o Can cause significant mass effect o Cowden-Lhermitte-Duclos (COLD) syndrome is considered new phakomatosis • Multiple hamartoma-neoplasia syndrome • Long term cancer screening (breast, thyroid)

=-

Coronal FLAIR MR shows subl!c, but bilateral hippocampal SI, temporal lobe cortex and insular COrlex ;>J signal increase and swelling in a child with proven Mycoplasma encephalitis.

• Glioblastoma Multiforme o White matter> > gray matter o Tumor infiltration of cortex, subpial extension may occur late o Hemorrhage, enhancement common o Primary GBM (older patient) 95% necrotic with thick irregular enhancing rim o Secondary GBM (younger patient) shows enhancing focus within lower grade tumor • Gliomatosis Cerebri o Tumor infiltrates but preserves underlying brain architecture o Two or more lobes affected o T2 hyperintense infiltrating mass enlarges cortex, basal ganglia o MRS shows elevated myo-inositol (mI) o Most are WHO grade II or III diffusely infiltrating astrocytoma • Meningioangiomatosis o Cortical mass with variable Ca++ o Linear &/or gyriform enhancement o Perivascular proliferation of vessels in meninges, cortex o May infiltrate along perivascular spaces, cause mass effect • Congenital Muscular Dystrophy o Cobblestone lissencephaly (overmigration) o Z-shaped brainstem o Hypoplastic rotated cerebellum (similar to Dandy-Walker continuum)

Coronal FLAIR MR shows swollen, hyperintense temporal lobe cortex ~ with relative sparing 01 the underlying white matter. OWl (not shown) revealed restricted diffusion in insular cortex, cingulale gyri.

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(Left) Axial NECT in a 4 month old with hypomyelination ~ shows decreased volume and while matter density. The thin arbors of while maller give a false impression that the cortex, especially in occipital poles, is thickened 81. (Right) Coronal T2WI MR in an 18 month old with Pelizaeus-Merzbacher disease (PMD) shows white maller hypomyeJinalion in occipital lobes 81 and cerebellum giving the appearance of prominent thick cortex.

=-

Tuberous Sclerosis Complex (Left) Axial FLAIR MR shows multiple large, (fat, thickened gyri with classic subcortical hyperinlensilies

E1

characteristic for cortical tubers. (Right) Axial T2WI MR in an 8 month old shows two maniFestations of tuberous sclerosis complex: Densely calcified, thickened transmantle hamartoma in the right parietal lobe and 2) characteristic "tubers" ~ in the left. Note multiple subependymal nodules 81.

=

(Left) Coronal PO FSf MR shows focaf cortical thickening with high signal of the expanded gyrus 81. (Right) Axial CECT in the same child shows a focal low density, noncalcified cortical/subcortical mass Ea. There is no enhancement, and there are neither subependymal nodules nor a foramen

of Monro

astrocytomas.

I 6 10

giant cell

Tuberous Sclerosis Complex

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TH ICK CORTEX

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(Left) Axial T2WI MR in a 10 month old with refractory seizures shows bilateral perisylvian foci of polymicrogyria giving the appearance of thick cortex. Note abnormal veins !:ll and subtle laminar heterotopia 81. (Right) Sagittal T1WI MR shows a thick cortex ~ lining the sylvian fissure in another child with bilateral primitive sylvian fissures and perisylvian polymicrogyria.

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pachygyria- Polymi crogyria (Left) Axial T2WI MR shows unilateral

fronto-parietal

polymicrogyria with blurring of the gray-white junction 81 and a nodular appearance (Right) Axial T2WI MR in a different child shows a much more extensively involved brain. Both hemispheres have a diffusely

=.

thickened,

striated cortex

due to polymicrogyria.

Hemimegalencephaly (Lcft) Axial T2WI MR shows expanded left hemisphere with diffuse overgrowth of while maller

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and some

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gray matter as well (Right) Axial T2WI MR shows a diffusely thickened, partially calcified left frontal cortex 81. The remainder of the left hemisphere has decreased signal intensity throughout gray and white matter~

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MR shows a thickened "cobblestone" cortex ~ and a hypoplastic cerebellum . The 4th ventricle =::I is opened inferiorly due to vermian hypoplasia and cephalad rotation.

DNET (Left) Axial FLAIR MR shows thickened, hyperintense cortically based mass with "rim sign" of hyperintensity

on FLAIR =::I. Lack of edema also is characteristic for ONET. (Right) Axial T7WI MR shows typical multinodular low signal intensity mass SI focally expanding the cortical mantle and remodeling the inner cortex ~ of the calvarium.

(Left) Axial PO rSf MR shows thickened, hyperintense cortex in a S year old with epilepsy. Without contrast-enhanced scan, this image would be indistinguishable from Taylor cortical dysplasia. (Right) Axial T7 C+ MR in the same patient shows several small

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foci

Ganglioglioma

surgery.

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THICK CORTEX

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(Left) Axial T2WI MR shows a striated ;50- and hypointense posterior fossa mass E!l2 that displaces the

4th ventricle~.

There is an

additional epidermoid cyst 1:11. (Right) Coronal T2WI MR shows thickened, striated-appearing cerebellar {olia ~ in a patient with Lhermiue·Ouc/os disease. In

this case, there was no association with Cowden syndrome.

Glioblastoma Multiforme (Left) Coronal T2WI MR in a 74 year old shows iso- & hyperintense right temporal lobe & insular mass 1:11 involving both gray & white maller. Note necrosis, Focal hemorrhage liB Tumor spread across anterior commissure thickens the left temporal lobe cortex ~ (Right) Axial FLAIR MR shows a typical case of meningioangiomatosis,

most

commonly found in NF2. Fine gyriform increased

density was present on NECT FLAIR MR shows linear increased

signal ~.

(Left) Axial T2WI MR in an adult shows involvement of the temporal pole cortex Sl hippocampus ffi & mesencephalon Involvement

of more

than

one lobe or region is typical of gliomatosis cerebri. (Right) Axial T2WI F5 MR in a 12 year old shows hyperintense, swollen gyri

I:]

with involvement

of the

midbrain E!l2 related to gliomatosis cerebri. WI 10 grade III diffusely infiltrating astrocytoma was found. (Courtesy M.

WarmUlh·Metz, MOr

I 6 13

THIN CORTEX

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Less Common • Multiple Sclerosis • Alzheimer Dementia • Multi-Infarct Dementia • Frontotemporal Dementia Rare but Important • Microcephaly • Subcortical Laminar Heterotopic Gray Matter • Inborn Errors of Metabolism (Gray Matter Disorders)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Is cortical thinning focal (typical for encephalomalacia) or generalized? • Is cortex thin but normal signal intensity? o If abnormal, consider infection, infarction, trauma, etc. • Child vs. adult o Child: History important • Prematurity, family history of inborn error of metabolism • Seizures (heterotopias, encephalomalacia) o Adult: Normal cognitive function or demented?

I 6 14

Helpful Clues for Common Diagnoses • Aging Brain o White matter (WM), not gray matter (GM) volume loss predominates in normal "successfully aging" brain • Posterior vermis, cerebellum> cerebral hemispheres • Cortical thinning minimal o "Black line" in visual, motor/sensory cortex common in normal older patients • Prematurity o Hemispheric WM almost completely unmyelinated ("wet brain") o Cortex always appears thin

• Pre- and post-central gyri myelinate early • Hyperintensity on Tl WI, hypointensity on T2WI normal o Note: White matter injury of prematurity spares GM • Undulating ven tricular borders, ventriculomegaly • Generalized volume loss due to " WM • Obstructive Hydrocephalus o "Maximal" hydrocephalus thins cortical mantle o May be difficult to distinguish from hydranencephaly on NECT • MR diagnostic • Cerebral Infarction, Chronic o Usually wedge-shaped, involves both cortex & underlying WM o "Hierarchy" of vulnerability to territorial or hypotensive ischemia • CAI hippocampus most sensitive • GM generally more vulnerable than WM o Collateral flow across pial watershed (border zones) may permit cortex within ischemic penumbra to survive o Thin rim of cortex may persist adjacent to densely ischemic core of infarct o Often hyperintense on T2/FLAlR, reflecting spongiosis/gliosis • Encephalomalacia, General o Trauma, infection, toxic-metabolic insults o May primarily affect GM, WM, or both o Can be generalized (e.g., following global hypo perfusion) or focal Helpful Clues for Less Common Diagnoses • Multiple Sclerosis o Multiple T2/FLAlR hyperintensities perpendicular to callososeptal interface o Chronic, severe multiple sclerosis (MS) causes variable brain atrophy • WM»GM • But normal-appearing GM may have abnormal metabolic profile with" NAA • Cortical loss in secondary-progressive MS common • Alzheimer Dementia o Alzheimer dementia (AD) is most common of all dementias o Best diagnostic clue = temporoparietal cortical atrophy + disproportionate hippocampal volume loss • Perihippocampal fissures widen

THIN CORTEX • Hippocampal, entorhinal cortex thins • Temporal horns enlarge • Perfusion MR, FDG, & PET can identify hypometabolic areas • Multi-Infarct Dementia o Also known as "vascular" dementia o Second most common dementia after AD • 10-30% of all dementing disorders o Imaging findings vary • Generalized, diffuse atrophy • Large ventricles, superficial sulci • Generalized cortical thinning • Focal territorial &/or lacunar infarcts • Subcortical WM T2/FLAIR hyperintensities • Diffuse bilateral, confluent deep WM hyperintensity secondary to arteriolosclerosis • Frontotemporal Dementia o One of several tauopathies, also known as Pick disease o Frontotemporal dementia (FTD) causes disproportionate frontotemporal atrophy o "Knife-like" gyri with very thin cortex o Subcortical WM usually hyperintense o Parietal, occipital lobes relatively spared Helpful Clues for Rare Diagnoses • Microcephaly o Small head size, • craniofacial ratio o Sutural overlap common o Simplified gyri with thin cortex o Shallow sulci o Many causes

Axial FLAIR MR in an intellectually normal 65 year old shows mild ventricular, sulcal enlargement. Thin rim of periventricular hyperintensity =::I is normal. Very mild cordcal thinning E1 is present.

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• Primary (genetic) microcephaly (e.g., microlissencephaly, many syndromes) • Secondary (nongenetic) microcephaly (e.g., TORCH infection, fetal alcohol syndrome) • Subcortical Laminar Heterotopic Gray Matter o "Band" heterotopia ("double cortex"): LlS1 or LISX1 • Thick inner band of dysplastic GM in subcortical WM • Overlying cortex thin (not all neurons "arrive") o Classic lissencephaly: (LIS1) • Shallow sylvian fissure ("hourglass" configuration of hemispheres) • Thin outer layer of GM • "Cell sparse" WM zone • Thick inner band of GM • Inborn Errors of Metabolism (Gray Matter Disorders) o Includes inborn errors of metabolism that affect WM > > GM o Many "poliodystrophies"; all uncommon o All have similar imaging appearance • Generalized atrophy with t sulci, thinned cortex • Cortical signal generally normal • BUT WM often hyperintense due to secondary axonal degeneration o Lysosomal (example: Neuronal ceroid lipofuscinosis) clue • Hypointense thalami (best seen on standard T2WI, not FSET2WI)

Axial T2WI MR in an elderly demented patient with su/xordcal arteriosclerodc leukoencephalopathy shows diffuse confluent hyperintensity in hemispheric white matter but only mild cortical thinning E1.

I 6 15

THIN CORTEX

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Prematurity

Prematurity

(Left) Sagittal T2WI MR in a normal 28 week premalUre infant shows thin cortical

ribbon 81. The brain is smooth, and only the central ~,

calcarine

and

It] fissures

parielOoccipital

are present. (Right) Axial T2WI MR in the same patient shows age-appropriate, undersulcated brain. The shallow, "squared" sylvian fissures are normal, as is the very thin cortical mantle overlying almost completely unmyelinated hemispheric while matter.

Prematurity (Left) Axial T2WI MR in a 32 week normal but premature infant shows more advanced 5ulcaliofl,

with deepening

of

the sylvian fissures. WM is stiff largely unmyelinated, and cortex appears thin 81. (Right) Axial T2WI MR in the

same premature baby shows thin cortical

mantle

overlying

almost completely unmyelinated white matter with the exception of hypointense WM Ii8 deep to the central sulci. Mild hypointensity of the cortex of pre-, post-central gyri E±I is normal.

Obstructive (Left) Coronal NECT in an 11 week old infant shows

"maxima/" hydrocephalus. Note massively enlarged ventricles

within

cranium.

Very thin, almost

imperceptible

am surrounds

huge

cortical mantle ventricles.

Posterior fossa appears

comparatively actually

small but is

normal

in size.

(Right) Coronal T2WI MR in the same patient shunting remain

large, cortical

very thin

I 6 16

after

shows ventricles

E±J.

mantle

Hydrocephalus

Obstructive

Hydrocephalus

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THIN CORTEX

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Obstructive

Hydrocephalus

Obstructive

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Hydrocephalus (Left) Axial T2WI MR in a patient with severe congenital hydrocephalus after shunting shows stenogyria with thinned, "crenelated"

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cortex along

interhemispheric fissure. (Right) Coronal T2WI MR in

the same patient shows more clearly the stenogyria ~ with thinned cortex along lhe interhemispheric fissure.

Cerebral

Infarction,

Chronic

Cerebral

Infarction,

Chronic (Left) Axial T2WI MR, obtained many years after near-tolallefl hemisphere infarction

secondary

to

internal carotid artery occlusion, shows thin rims of gliolic hyperintense cortex ~ surrounding cystic encephalomalacia. (Right) Axial FLAIR MR in a patient with systemic lupus erylhemalosus and multiple old infarcts shows diffusely atrophic right hemisphere wilh enlarged sulci, shrunken gyri, and markedly lhinned

cortexB.

Cerebral

Infarction,

Chronic

Cerebral

Infarction,

Chronic (Left) Axial NEeT in a child wilh Slurge-Weber syndrome shows small left hemisphere with very atrophic, calcified cortex. Dystrophic Ca++ is in brain (nolleptomeningeal angioma),

and cortical

thinning is secondary chronic

to

venous (not arteria/)

ischemia. (Right) Axial T2WI MR in the same patient shows how thin the affeeled cortex is compared to the normal

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right side.

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THIN CORTEX

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Encephalomalacia, General

Encephalomalacia, General

Multi-Infarct Dementia

Frontotemporal Dementia

(Left) Coronal T2WI MR obtained in a child 5 months after initial neonatal

group

B

Streptococcal meningitis shows generalized volume loss with gliosis and thinned cortex ~ in the leFt temporal lobe. (Right) Coronal T2WI MR in child with Rasmussen encephalitis shows thinned cortex around the left sylvian Fissure=:I compared to the normal right side.

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(Left) Axial T2WI MR shows hypointense bodies of caudate nuclei confluent plaques and thin cortex 81. (Right) Axial T2WI MR shows disproportionate atrophy of occipital lobes with striking cortical thinning [;8 The Heidenhain variant of Alzheimer dementia primarily a(Fects the occipital cortex.

=

=..

(Left) Axial NECT shows classic mulli·infarct dementia with multi-territorial infarctions.

cortical

Peri ventricular

white matter hypodensity, multiple cortical infarcts EB thinned cortex, shrunken parielooccipilal

gyri

E:II

are

all seen. (Right) Axial FLAIR MR shows predominate

I 6 18

Frontal lobe atrophy with striking cortical thinning. Some gyri demonstrate a classic" knife-like II appearance =:I. There is also associated white matter T2 hyperintensity 81.

THIN CORTEX

Microcephaly (Left) Axial T2WI MR in an infant wlhead circumference 3 standard deviations below mean shows simplified gyral pattern, thin corlex i7 ~ shallow sulci, & broad flat gyri. The infant had familial

autosomal recessive microcephaly. fRight) Axial T2WI MR in an 8 month old with microcephaly related to congenital CMV shows thin cortex [;8 delayed myelination. Germinolytic cysts ffi periventricular calcifications & large

a

subarachnoid spaces are also seen.

Subcortical

laminar Heterotopic Gray Matter

Subcortical

laminar Heterotopic Gray Matter (Left) Axial T2WI MR in a 2 week old with Miller-Dieker syndrome shows

"hourglass-shaped"

=-

brain,

smooth thin cortex thick band of subcortical laminar heterotopic gray matter [;8 and primitive veins in sylvian fissures !:ill. (Right) Sagiltal T1 WI MR shows subcortical "bands II or II ribbons II of heterotopic gray matter ~ separated from thinned overlying cortex S'I by a strip of myelinated white maller

Inborn Errors of Metabolism (Gray Matter Disorders)

Inborn Errors of Metabolism (Gray Matter Disorders) (Left) Axial T2WI MR in a child with neuronal ceroid lipofuscinosis (CLN3 or Batten variant) shows markedly thinned cortex S'I throughout both hemispheres. Thalami are shrunken, very hypointense fRight) Axial T2WI MR in a child with lysosomal storage disorder (CLN 7 ) shows generalized atrophy with very thin cortex !:ill, classic "dark"thalamiG & basal ganglia S'I.

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I 6 19

FOCAL CORTICAL MASS

DIFFERENTIAL DIAGNOSIS Common • Cerebral Ischemia-Infarction, Acute (Cortical) • Metastases, Parenchymal • Oligodendroglioma • Cerebritis • Diffuse Astrocytoma, Low Grade Less Common • Venous Infarction • Pleomorphic Xanthoastrocytoma • Tuberous Sclerosis Complex • Pachygyria-Polymicrogyria (Focal Cortical Dysplasia) • DNET • Ganglioglioma Rare but Important • Pilocytic Astrocytoma • Cavernous Malformation • Desmoplastic Infantile Ganglioglioma • Viral Encephalitis • Astroblastoma

ESSENTIAL INFORMATION

I

Usually solid, may be complex with central cystic or necrotic areas o May be hemorrhagic with increased Tl SI o May be solitary but frequently are multiple & bilateral • Oligodendroglioma o T2 hyperintense mass, variable enhancement o Calcification is common o Frontal> other lobes; usually a single mass • Cerebritis o Gray & white matter are often involved together o T2 hyperintense with variable enhancement & variable DWI appearance o Cerebritis essentially represents a developing brain abscess & is commonly caused by pyogenic bacteria o May be solitary or multifocal • Diffuse Astrocytoma, Low Grade o T2 hyperintense WM mass, may involve gray matter o May mimic stroke; however ADC values typically normal to elevated o No or minimal enhancement is typical o Usually a solitary mass o Bilateral disease may be seen in gliomatosis cerebri, a rare infiltrative process o

Helpful Clues for Less Common Diagnoses • Venous Infarction o T2 hyperintense lesion o Associated hemorrhage is very common, often at gray-white junctions o Typically related to dural sinus thrombosis o May be multiple & bilateral if the superior sagittal sinus is involved • Pleomorphic Xanthoastrocytoma o Cortical enhancing mass with adjacent cyst, classic appearance o Enhancement extends to meninges, causing a "dural tail" o Temporal lobe is most common location o Occurs in young adults • Tuberous Sclerosis Complex o Multiple cortical "tubers" = cortical hamartomas are T2 hyperintense & nonenhancing o Calcified subependymal nodules ± enhancing giant cell astrocytoma at the

foramen of Monro is classic o

6 20

Usually a multiple & bilateral process

FOCAL CORTICAL

en

MASS

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When solitary, consider Taylor cortical dysplasia • Pachygyria-Polymicrogyria (Focal Cortical Dysplasia) o Limited to gray matter; focal or regional thickening of the cortex o Variable T2 appearance; no enhancement o Many have deep sulci with thickened cortex that mimics a mass o Occasionally a linear region of increased T2 signal connects the focal cortical dysplasia with the ependymal surface • DNET o Multicystic cortical mass, frequently seen in the temporal lobe o "Bubbly" appearance classic o Variable enhancement o Solitary lesion in a young adult typical • Ganglioglioma o Enhancing (multi)cystic mass; may be solid or have a cyst & nodule appearance o Calcification is common o Temporal lobe is most common location o Solitary lesion o

Helpful Clues for Rare Diagnoses • Pilocytic Astrocytoma o Enhancing nodule with or without an associated cyst, most common appearance o Children> adults o Cerebellum & optic pathways are frequent locations o May rarely occur in the cortex o Solitary lesion Cerebral

Ischemia-Infarction, (Cortical)

• Cavernous Malformation o Heterogeneous mass with a "mulberry" appearance related to blood products o Hemosiderin ring "blooms" on GRE; Tl bright locules o May have increased CT density &/or punctate calcifications o Sometimes associated with a developmental venous anomaly o May be deep as well as cortical o May be solitary or multiple, bilateral • Desmoplastic Infantile Ganglioglioma o Frontal/parietal locations common o Cystic mass with enhancement o May be massive, occupy majority of hemisphere o Presentation occurs when younger than 6 months • Viral Encephalitis o Cortical swelling; minimal enhancement o Not in a typical vascular territory o Temporal, frontal, cingulum are often seen in herpes simplex virus • Astroblastoma o Large hemispheric solid & cystic mass with heterogeneous enhancement of solid portion o Superficial mass involves cortex & subcortical WM typical o Children & young adults

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Acute Metastases,

Parenchymal

I & mass effecl in the right middle cerebral artery vascular distribution related to acute ischemia. A wedge-shaped lesion in a

Axial OWl MR shows hyperinlensily

vascular territory is classic.

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2 masses localed al Ihe gray-while each with low density in the adjacent while maller representing vasogenic edema H2.

Axial

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(Left) Axial FLAIR MR shows a high signal mass SI containing a {ocal area of lower signal:±" representing a calcification within the tumor. A calcified frontal lobe mass involving the cortex & subcortical while maller is typical of oligodendroglioma. (Right) Coronal T7 C+ MR shows patchy enhancement significant edema, & mass effect. A mature abscess wall & central cavity are not yet

present, differentiating cerebritis from abscess.

Diffuse Astrocytoma,

Low Grade

Venous Infarction

(Left) Axial T2WI MR shows a well-circumscribed frontal lobe diffuse astrocytoma, low grade Ea. There was no significant enhancement of the mass following contrast injection. (Right) Axial NECT shows ill-defined low density ~ associated with subcortical hemorrhages and a hyperdense superior

=

sagittal sinus E:I. Ilemorrhage is common in venous infarction. The parenchymal findings can mimic a primary tumor or

metastases.

Pleomorphic (Left) Axial T7 C+ MR shows enhancing parenchymal nodule SI associated with a cyst in the temporal lobe. These features are nonspecific but are typical of PXA. (Right) Axial T2WI MR shows several areas of high T2 signal & slight mass effect representing cortical hamartomas ("tubers")~. There are several subependymal nodules, some with dark signal suggesting calcification ~ Subependymal nodules often enhance, while cortical

=

I 6 22

tubers rarely do.

Xanthoastrocytoma

Tuberous Sclerosis Complex

FOCAL CORTICAL MASS

Pachygyria-Polymicrogyria Cortical Dysplasia)

CJ)

:0:c:

(Focal

DNET (Left) Axial T2WI MR shows bilateral deep sulci lined with pebbly dysplastic cortex Band-like heterotopic gray mailer is also seen bilaterally E2. The lack of normal-appearing gyri & unusual cortex makes this a mimic of focal mass. (Right) Sagittal T1 WI MR shows a mass in the parieto-lemporal-occipital junction with a central cystic area liB The mass did not enhance with contrast

=.

material.

A mullicystic

"bubbly" appearance is common.

Pilocytic Astrocytoma (Left) Coronal T I C+ MR shows an enhancing nodule ~ associated with a tumor cyst E2. The findings are not specific but are typical of ganglioglioma. The temporal lobe is a very common location for ganglioglioma. Patients typically present with seizures. (Right) Axial T7 C+ MR shows an occipital lobe enhancing nodule E2 associated with a small cyst The findings are not specific but are typical of pilocytic

=.

astrocytoma.

Cavernous Malformation (Left) Coronal T2 CRE MR shows typical hypointense appearance of a cavernous malformation [;8 The lesions may be calcified but usually "bloom" 0/1 CRE due to contained blood products. They may be associated with developmental venous anomaly. (Right) Coronal T7 C+ MR shows a very large right hemispheric, predominantly cystic mass with an enhancing mass along the medial wall Findings are nonspecific but typical of this entity.

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I 6 23

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DIFFERENTIAL DIAGNOSIS Common • Cerebral Ischemia-Infarction, Acute • Cerebral Contusion • Hypotensive Cerebral Infarction • Status Epilepticus • Herpes Encephalitis

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Less Common • Diffuse Astrocytoma, Low Grade • Acute Hypertensive Encephalopathy, PRES • Vasculitis • Oligodendroglioma • Anaplastic Oligodendroglioma • Hypoxic-Ischemic Encephalopathy, NOS • DNET • Pleomorphic Xanthoastrocytoma • Tuberous Sclerosis Complex • Cerebritis • Hypoglycemia Rare but Important • MELAS(Acute Presentation) • Creutzfeldt-jakob Disease (C]D) • Dysplastic Cerebellar Gangliocytoma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Vast majority of cortical lesions are related to ischemia & trauma • Remainder of lesions much less common and include primarily tumors & infections • DWI may help differentiate lesions

I 6 24

Helpful Clues for Common Diagnoses • Cerebral Ischemia-Infarction, Acute o T2 hyperintensity in a typical vascular distribution (ACA, MCA, PCA) o Wedge-shaped, involves gray matter (GM) & white matter (WM) o DWI restriction • Cerebral Contusion o T2 hyperintensity in inferior frontal & temporal lobe GM & subcortical WM o Blood products nearly always present oCT: Patchy superficial hemorrhages with surrounding edema o History of trauma • Hypotensive Cerebral Infarction o "Border zone" or watershed infarct related to insufficient cerebral blood flow

T2 hyperintense cortically based, wedge-shaped lesions at border zone between vascular territories o Edematous gyri with local mass effect o May involve basal ganglia (BG) & thalamus o DWI positive acutely • Status Epilepticus o T2 hyperintensity in GM &/or subcortical WM with mild mass effect o May focally involve hippocampus or corpus callosum o DWI positive acutely; variable enhancement • Herpes Encephalitis o T2 hyperintensity in the limbic system & temporal lobes; DWI positive o Subtle blood products, patchy enhancement common o Typically bilateral, but asymmetric o Acute onset, often with fever; may present with seizures o

Helpful Clues for Less Common Diagnoses • Diffuse Astrocytoma, Low Grade o Infiltrating T2 hyperintense WM mass o May extend to involve cortex o No enhancement typical • Acute Hypertensive Encephalopathy, PRES o Patchy cortical/subcortical PCA territory lesions in a patient with severe acute/subacute hypertension (HTN) o Parietooccipital T2 hyperintense cortical lesions in 95% o DWI: Usually normal o Variable patchy enhancement o Diverse causes, clinical entities with HTN • Vasculitis o Multiple small areas of T2 hyperintensity in deep & subcortical WM, often bilateral o GM involvement common o DWI positive in acute setting o Variable enhancement • Oligodendroglioma o Calcified T2 hyperintense frontal mass o Slowly growing but diffusely infiltrating cortical/subcortical mass o Variable enhancement • Anaplastic Oligodendroglioma o Calcified frontal lobe mass involving cortex/subcortical WM, ± enhancement o May appear discrete, but always infiltrative

CORTICAL

HYPERINTENSITY

T2/FlAIR

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Difficult to differentiate from oligodendroglioma • Hypoxic-Ischemic Encephalopathy, NOS o Bilateral cortical involvement common o Oeep gray nuclei often involved o OWl positive in acute setting • DNET o Well-demarcated, wedge-shaped "bubbly" cortical mass o Temporal & parietal lobes most common o May remodel overlying bone o Typically a young patient with longstanding seizures • Pleomorphic Xanthoastrocytoma o Supratentorial 1'2 hyperintense cortical mass with adjacent enhancing dural "tail" o Enhancing nodule abuts pia o Temporal lobe most common site o Found almost exclusively in young adults • Tuberous Sclerosis Complex o 1'2 hyperintense cortical & subcortical tubers o Calcified subependymal nodules nearly always present o Subependymal giant cell astrocytoma 15% o Taylor cortical dysplasia: Solitary tuber in cortex & subcortical WM • Cerebritis 01'2 hyperintense "mass" with mass effect o Typically DWI positive o Patchy enhancement • Hypoglycemia .. o Severe parietooccipital edema or mfarcts m a newborn with seizures o

Axial T2WI MR shows a local cortical hyperintensity & edema ~ in the medial posterior Iron tal lobe. OWl restriction

&

history

cerebral artery inlarct.

confirmed

this

acute

anterior

Parietal, occipital lobes > temporal or BG o OWl: Restricted diffusion, decreased AOC (may be transient) o

Helpful Clues for Rare Diagnoses • MELAS (Acute Presentation) o Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes o Multifocal bilateral 1'2 hyperintensities, typically reversible o Predominantly GM involvement, may involve subcortical WM o MRS shows lactate peak • Creutzfeldt-jakob Disease (CjD) o Rapidly progressing, fatal, potentially transmissible dementing disorder o Progressive 1'2 hyperintensity of BG, thalamus, & cerebral cortex (gyriform) o OWl positive o Frontal & temporal lobe cortex most commonly involved o Occipital lobe involvement in Heidenhain variant • Dysplastic Cerebellar Gangliocytoma . o Enlarged 1'2 hyperintense cerebellum with preservation of folia o Striated, laminated, or "tigroid" appearance o Associated with Cowden syndrome

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Alternative Differential Approaches • Temporal lobe cortical lesions: Ischemia, contusion, status epilepticus, herpes encephalitis, ONET, PXA

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(Left) Axial T2WI MR shows hyperinlensily in the cortex & subcortical white matter in a patient with a severe hypotensive event & a Iypical walershed patlem of ischemia. (Righi) Coronal FLAIR MR shows hyperinlensily in the cortex & subcortical while maller of Ihe temporal lobe in a parienl imaged following a long episode of slatus epi/epricus. OWl may be positive acutely. Perfusion MR shows marked hyperemia on Ihe side of Ihe epilepric focus aculely.

=

Diffuse Astrocytoma, (Left) Axial rLAIR MR shows difruse swelling & hyperintensity in Ihe righl temporal lobe & cingulate gyri. Ilerpes encephaliris typically allecls Ihe limbic system & is commonly bilateral. OWl is posirive acutely. (Right) Axial T2WI MR shows a difluse hyperintense fronlallobe mass E1 with involvement of the corlex & underlying white malter. Allhough Ihese tumors may appear discrete, they are infiltrative. Tumor cells eXlend beyond Ihe region of signal change.

Acute Hypertensive

Encephalopathy,

PRES

I 6 26

(Left) Axial T2WI MR shows marked hyperinlensily & swelling 01 Ihe bilaleral fronlO·parietal cortex II::] in Ihis palient wilh PRES.OWl was negalive. PRESIypically involves the posterior circulation but may extend into Ihe fronlallobes when severe. (Right) Axial FLAIR MR shows abnormal hyperinlensily in the cortex & subcortical white maller of Ihe parielallobes in rhis parienl with vasculiris. OWl is positive aculely. Bi/aleral involvement is common.

Low Grade

CORTICAL

HYPERINTENSITY

T2/FLAIR III

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C. OJ ., III

DNET (Left) Axial T2WI MR shows a heterogeneous frontal lobe mass. Calcification was

::l

present on the corresponding CT. Enhancement is noted in about 50% of these tumors. Imaging of grade If & grade Ifl (anaplastic) tumors is often similar. (Right) Coronal FLAIR MR shows a cortically based, hyperintense "bubbly" mass in this young patient. These low grade tumors are most common in the temporal & parietal lobes & often remodel the adjacent skull.

Pleomorphic

Xanthoastrocytoma

Tuberous Sclerosis Complex (Left) Axial T2WI MR shows a heterogeneous temporal lobe mass with a large cystic

component

=. Post-contrast

imaging typically shows an enhancing nodule abutting the pial surface. Surgical resection of PXA is usually curative. (Right) Axial FLAIR MR shows multiple hyperintense cortical & subcortical tubers, typical of TSC. Calcified subependymal nodules are present 81 but are better seen on T1 & T2 sequences as well as CT.

(Left) Axial FLAIR MR shows hyperintensity & swelling of the posterior temporal, opercular, parietal, & occipital cortex with blurring of gray & white matter. Involvement of the basal ganglia is also noted. Imaging is typical of profound hypoglycemia. (Rigllt) Axial T2WI MR shows marked enlargement of the cerebellum with preservation of the cerebellar folia pattern, giving a characteristic "striated cerebellum" or "tigroid" appearance.

=

I 6 27

CORTICAL ENHANCEMENT

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• Status Epilepticus o Patchy or gyriform enhancement o Underlying white matter (WM) spared • Acute Hypertensive Encephalopathy,

DIFFERENTIAL DIAGNOSIS Common • Cerebral Infarction, Subacute • Herpes Encephalitis • Hypotensive Cerebral Infarction • Status Epilepticus • Acute Hypertensive Encephalopathy, • Cerebritis

PRES

PRES

Less Common • Malignant Gliomas • Vasculitis • Hypoglycemia Rare but Important • MELAS • Cerebral Hyperperfusion • Osmotic Demyelination

Syndrome Syndrome

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Cerebral Infarction, Subacute o Gyriform enhancement characteristic o Petechial hemorrhage or pseudolaminar necrosis often seen (Tl hyperintense) o DWI has typically normalized • Herpes Encephalitis o Predilection for limbic system o Typically bilateral, asymmetric; DWI + o Enhancement patchy or gyriform • Hypotensive Cerebral Infarction o Commonly at cortical "border zones" o Gyriform enhancement subacutely

Cerebral

Infarction,

Patchy cortical/subcortical PCA territory lesions in a patient with hypertension o Patchy enhancement, may be gyriform • Cerebritis o T2 hyperintense lesion with mass effect & patchy enhancement; DWI + o

Helpful Clues for Less Common Diagnoses • Malignant Gliomas o May involve cortex or have subpial spread • Vasculitis o Multiple small areas of T2 hyperintensity in deep & subcortical WM, often bilateral o Enhancement patchy or gyriform • Hypoglycemia o Severe parietooccipltal edema/infarcts o Patchy enhancement Helpful Clues for Rare Diagnoses • MELAS o Multifocal bilateral T2 hyperintensities o Patchy enhancement • Cerebral Hyperperfusion Syndrome o Carotid endarterectomy, angioplasty, or post-stenting patient o Increased vessel & patchy enhancement • Osmotic Demyelination Syndrome o May rarely involve cortex o Pseudolaminar necrosis &/or gyriform enhancement rare

Subacute

I 6 28

Axial T7 C+ MR shows marked gyri/arm enhancement in this subacute infarct. Remember the "2-2-2 rule" for strokes: Enhancement begins at 2 days, peaks at 2 weeks, & generally disappears by 2 months.

Coronal T7 c+ MR shows gyri/arm enhancement in the temporal lobes & insular cortex in this herpes

encephalitis involvement

patient.

Bilateral

=but

asymmetric

of the limbic system is most common.

CORTICAL

ENHANCEMENT

,.c: Ul

Status Epilepticus (Lcft) Coronal T7 C+ MR shows diffuse gyriform cortical enhancement & basal ganglia enhancement ~. T7 hyperintensity representing pseudolaminar cortical necrosis is common in this type of ischemia. (Right) Coronal T7 C+ MR shows gyriform & meningeal enhancement in the right parietal & occipital lobes, related to status epileplicus. Ten days after imaging, once the patient's seizures were controlled, there was resolution of enhancement

Acute Hypertensive

Encephalopathy,

PRES (Left) Axial T7 C+ MR shows multifocal areas of punctate enhancement

=..

active blood-brain

indicating barrier

disruption in this case of PRES. PRESis typically completely reversible but may become complicated by hemorrhage or infarcts. (Right) Axial TI C+ MR shows patchy enhancement SII within an ill-defined "mass ". The lesion showed restriction

on OWl (not

shown), typical of cerebritis. This represents the early cerebrilis stage of abscess {ormation.

Vasculitis (Left) Axial T7 C+ MR shows gyriform & patchy enhancement. OWl images (not shown) reveal bright diffusion indicating

restriction acute ischemia.

Multiple vascular distributions are commonly involved. (Right) Corolla I T 1 C+ MR shows increased vascularity in the left hemisphere with ill-defined punctate enhancement suggesting blood-brain barrier leakage in this carotid endarterectomy patiellt. OWl is normal, & there is increased perfusion (rCBT).

=.

I 6 29

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SOLITARY WHITE MATTER LESION

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DIFFERENTIAL DIAGNOSIS Common • Enlarged Perivascular Spaces (PVS) • Lacunar Infarction • Arteriolosclerosis • Multiple Sclerosis • Metastasis • ADEM • Reactive Astrocytosis (Gliosis) • Glioblastoma Multiforme Less Common • Encephalitis (Miscellaneous) • Oligodendroglioma • Diffuse Astrocytoma, Low Grade • Anaplastic Astrocytoma • Oligoastrocytoma Rare but Important • Thrombosis, Cortical Venous • Osmotic Demyelination Syndrome • Gliomatosis Cerebri

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Majority of solitary white matter (WM) lesions are vascular or neoplastic

I 6 30

Helpful Clues for Common Diagnoses • Enlarged Perivascular Spaces (PVS) o Sharp margins & lentiform, follow CSF on all sequences o May be associated with gliosis in elderly (FLAIRhyperintense rim) o Solitary enlarged PVS unusual, smaller characteristic lesions often seen elsewhere in the brain o Usually in lentiform nuclei, rarely in thalamus • Lacunar Infarction o Usually in basal ganglia (BG), thalamus, internal capsules, less commonly in periventricular WM o Mildly irregular, but sharp margins, T2 hyperintense rim, ± GRE hypointense hemosiderin rim o Often associated with more confluent WM arteriolosclerotic or hypertensive changes • Arteriolosclerosis o Usually multiple & confluent, but can be solitary early in the disease

Usually in deep & periventricular WM o Associated with lacunar infarcts • Multiple Sclerosis o Corpus callosum (CC) & peri 4th ventricular involvement in a young adult o Acute tumefactive lesions large with hypointense T2 ring that enhances, usually with little mass effect o Solitary lesion commonly in deep or peripheral WM & at the onset of typical disease or with tumefactive lesions o Enhancement may be ring-like or "U" shaped in the subcortical fibers • Metastasis o May be punctate to massive, with variable surrounding edema, mass effect o Hemorrhagic in renal cell, melanoma, choriocarcinoma o Hyperintensity, edema, & mass effect less prominent in posterior fossa, but risks higher o Solitary at presentation in 45-50% • ADEM o Usually multifocal WM lesions, but can be solitary o Range from punctate to flocculent, with enhancement, faint & fuzzy early, ring-like later o Usually 10-14 days following infection or vaccination o Often occurs in children 3-5 years, but can occur at any age • Reactive Astrocytosis (Gliosis) o Gliosis is T2 hyperintense without mass effect & often associated with focal atrophy (encephalomalacia) o FLAIRhelpful in separating microcystic encephalomalacia & gliosis (hyperintense) from macrocystic changes (hypointense) o Brain's only response to insult: Infectious, stroke, trauma • Glioblastoma Multiforme o Irregular WM mass with ring enhancement, hemorrhage o Mass effect, heterogeneous signal typical o Often involves, extends across CC o

Helpful Clues for Less Common Diagnoses • Encephalitis (Miscellaneous) o Most non-herpes encephalitides involve BG, thalamus, midbrain, & WM o Poorly marginated, mild mass effect

SOLITARY WHITE MATTER LESION

Usually multiple, but may be solitary in midbrain, or with solitary cerebritis o Variable enhancement of the parenchyma or meninges Oligodendroglioma o Peripheral lesion, often with significant cortical involvement o Frontal & temporal lobes, often with skull changes due to slow growth o Calcification common, enhancement from none to intense Diffuse Astrocytoma, Low Grade o Often peripheral, but occurs in any lobe & brainstem o Poorly marginated, cortical involvement less common o Usually no enhancement, hemorrhage, or calcification Anaplastic Astrocytoma o WM tumor midrange between GBM & low grade with significant overlap o Typically more enhancement & mass effect than low grade astrocytoma Oligoastrocytoma o Similar to low grade or anaplastic astrocytoma in appearance o May arise from a lower grade oligodendroglioma or astrocytoma o

•

•

•

•

Helpful Clues for Rare Diagnoses • Thrombosis, Cortical Venous o Lesions usually solitary when isolated cortical venous o Dural sinus: Multiple lesions

Axial T2WI MR shows a sharply demarcated CSF-like

hyperintensity near the anterior commissure internal capsule. This is a typicallaealian for a solitary enlarged PVS.

=

&

lower

& appearance

,.-r::: CIl

Deep venous: Bilateral thalamic T2 hyperintensity without diffusion restriction unless infarct has developed o Usually subcortical WM, sparing the cortex, often hemorrhagic o Look for the thrombosed cortical vein which may be hyperintense on Tl or FLAIR,hypointense on GRE • Osmotic Demyelination Syndrome o Central pontine myelinolysis: Pontine hyperintensity sparing the periphery & cortical spinal tract, round or trident-shaped, usually solitary o Extra-pontine myelinolysis: BG & WM lesions usually bilateral, but may be solitary • Gliomatosis Cerebri o Extensive multilobar or diffuse cerebral hyperintensity with minimal mass effect o Unilateral multilobar disease may appear to be a large solitary lesion o

o

Alternative Differential Approaches • Solitary white matter lesions in a child: Enlarged PVS, ADEM, gliosis, encephalitis, low grade astrocytoma • Solitary white matter lesions in an adult: Enlarged PVS, lacunar infarct, arteriolosclerosis, MS, metastasis, ADEM, gliosis, gliomas, encephalitis, venous thrombosis, osmotic demyelination syndrome, gliomatosis cerebri

Axial T2WI MR shows an acute lacunar infarcUon

involving the corticospinal tract in the cerebral peduncle

I 6

r:=.

Lacunar infarctions most commonly occur in the basal ganglia and thalamus.

31

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Multiple

Sclerosis

(Left) Axial T2WI MR shows hyperintensity in the pons without mass effect =:I related to arterioloscferosis. These WM lesions are most common in peri ventricular & subcortical WM. Arteriolosclerosis is expected in patients with a history of hypertension &lor diabetes. (Right) Axial FLAIR MR shows a large hyperintense

lUmefactive

lesion

=

with

MS lesion.

Metastasis

ADEM

(Left) Axial FLAIR MR shows a solitary T2 hyperintense lesion in the juxta cortical right frontal lobe white maller. There is a small central focus of isointensity =:I that may be due to hemorrhage in this testicular embryonal carcinoma metastasis. (Right) Axial FLAIR MR shows a large, tumefactive ADEM lesion =:I with hyperinlensily sparing the cortex. The mass effect is less than expected for lesion size. Gadolinium

enhancement was at the peripheral margin.

Reactive Astrocytosis (Gliosis) (Left) Axial FLAIR MR shows increased signal intensity in the medial left temporal lobe =:I (gliosis), with dilatation of the left temporal horn !J:il in this seizure patient

mesia/temporal

with

sclerosis.

(Right) Axial T2WI MR shows a heterogeneous,

discrete appearing mass

I 6 32

=

in the posterior temporal/occipital region. Lack of surrounding edema is very unusual for CBM. The hypointensity is likely related to blood products, common in CBM.

Glioblastoma

Multiforme

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SOLITARY WHITE MATTER LESION

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Encephalitis

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(Miscellaneous) (Left) Coronal T2WI MR shows edema & hyperintensity of the temporal lobe & insula with involvement of gray & white matter with significant mass effect due to a viral encephalitis. The lateral neocortical location is rare in herpes. (Right) Axial FLAIR MR shows a hyperintense white maller mass involving the cortex with mild mass effect Although this may mimic acute stroke, extension into the ACA distribution makes that diagnosis unlikely

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Diffuse Astrocytoma,

low Grade

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Astrocytoma (Left) Axial FLAIR MR shows

a frontal lobe mass centered in the white matter with focal low signal likely related to cystic change. Involvement & expansion of the overlying cortex is less prominent than a typical oligodendroglioma. (Right) Axial fLAIR MR shows a hyperintense WM mass

=

involving

the insula.

Although the mass appears discrete,

tumor cells often

extend beyond the signal abnormality Imaging mimics a low grade

=.

astrocytoma.

(Left) Axial T2WI MR shows

a WM lesion with mild cortical involvement & mass effect related to venous

=

ischemia.

T2 appearance

is

nonspecific, but OWl & cortical

vein abnormality

were definitive. (Right) Axial T2WI MR shows striking hyperintensity within the central pons with mild mass effect due to central pontine myelinolysis (CPM). The mass effect & sharp geographic appearance favors CPM over arteriolosclerosis or

=

neopbsm.

I 6 33

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CONFLUENT WHITE MATTER LESIONS

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DIFFERENTIAL DIAGNOSIS Common • Aging Brain, Normal • Arteriolosclerosis • Chronic Hypertensive Encephalopathy • Multiple Sclerosis • Multi-Infarct Dementia • Hypotensive Cerebral Infarction • Cerebral Amyloid Disease Less Common • Glioblastoma Multiforme • Radiation and Chemotherapy • HIV Encephalitis ·PML • Encephalitis (Miscellaneous) • CADASIL • Inherited Metabolic Disorders o Metachromatic Leukodystrophy (MLD) oX-linked Adrenoleukodystrophy (XLD) o Alexander Disease o Canavan Disease o Zellweger o Van der Knaap Leukoencephalopathies o Hypomyelination • ADEM • Enlarged Perivascular Spaces Rare but Important • Lymphoma, Primary C S • Lymphoma, Intravascular (Angiocentric) • Gliomatosis Cerebri • Hypothyroidism • CO Poisoning • Subacute Sclerosing Panencephalitis • Drug Abuse • Maple Syrup Urine Disease

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Confluent white matter (WM) lesions are all T2/FLAIR hyperintense & CT hypodense

I 6 34

Helpful Clues for Common Diagnoses • Aging Brain, Normal o Usually multiple T2 hyperintensities, but can become confluent in late elderly o Less severe for age than arteriolosclerosis or chronic hypertensive encephalopathy o Lack history of hypertension, diabetes, or other vascular disease

• Arteriolosclerosis o Confluent periventricular & deep WM o Spares corpus callosum (CC) • Chronic Hypertensive Encephalopathy o Basal ganglia (BG) lacunae typical o Usually deep, periventricular confluent T2 hyperintensities o Hypointense micro hemorrhages on T2* common • Multiple Sclerosis o Radiating peri ventricular location, "Dawson fingers" o Acute tumefactive lesions large with hypointense T2 ring that enhances variable mass effect • Multi-Infarct Dementia o Similar to arteriolosclerosis & chronic hypertensive encephalopathy, but usually with peripheral & cortical infarcts o BG & pons infarcts common • Hypotensive Cerebral Infarction o Chronic hemodynamic hypotensive lesions are multifocal or confluent parasagittal WM lesions o Acute hypotension may result in confluent juxta cortical or diffuse WM lesion often associated with cortical necrosis • Cerebral Amyloid Disease o Confluent WM hyperintensity less common than peripheral multifocal lesions o Multifocal juxtacortical small infarcts & hemorrhages of varying ages common, with little to no BG involvement Helpful Clues for Less Common Diagnoses • Glioblastoma Multiforme o Large confluent mass that may cross CC o Can have unusual spread patterns: Ependymal, pial, which can create large confluent regions • Radiation and Chemotherapy o Radiation necrosis may mimic high grade neoplasm; has low cerebral blood volume o Leukoencephalopathy: Diffuse confluent hyperintensity • HIV Encephalitis o Confluent diffuse WM hyperintensity with atrophy classic; spares subcortical U-fibers

·PML o

Large multifocal or confluent subcortical WM lesions without mass effect

CONFLUENT

en

WHITE MATTER LESIONS

• Encephalitis (Miscellaneous) o Herpes encephalitis: Medial temporal & inferior frontal confluent T2 hyperintense • Predominantly cortical, but involves WM o Most non-herpes encephalitides involve BG, thalamus, midbrain, & WM • CADASIL o Onset at age 20-40 is common o Bilateral anterior temporal subcortical lesions appear eaL"lyin diagnosis o External capsule involvement somewhat specific o After age SO, frontal lobe involvement develops into confluent lesions • Inherited Metabolic Disorders o Usually diffuse, confluent o Mitochondrial usually multifocal o All present in infancy, childhood, or rarely in young adults (Alexander disease, MLD) • ADEM o Multifocal lesions, punctate to flocculent o May become confluent when massive o Enhancement: Faint & fuzzy early, ring-like later o Usually 10-14 days following infection or vaccination • Enlarged Perivascular Spaces o Variable-sized clusters, CSF-like o Can cause focal mass effect Helpful Clues for Rare Diagnoses • Lymphoma, Primary CNS o Callosal peri ventricular, may be peripheral, central isointense mass, modest mass effect

c: "

• Lymphoma, Intravascular (Angiocentric) o Often confluent radiating periventricular hyperintensity along deep medullary veins • Gliomatosis Cerebri o Confluent or diffuse with minimal mass effect is typical • Hypothyroidism o Diffuse WM hyperintensity in Hashimoto encephalopathy • CO Poisoning o Diffuse WM hyperintensity in severe cases o Globi pallidi hyperintensity classic • Subacute Sclerosing Panencephalitis o Diffuse T2 hyperintensity extending into the gyri with CC involvement o Diffuse atrophy with severe WM volume loss late o 0 enhancement • Drug Abuse o Periventricular or diffuse WM pattern with inhaled heroin or rare vasculitis • Maple Syrup Urine Disease o Diffuse cerebellar & brainstem WM T2 hyperintensity with lesser supratentorial involvement

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Alternative Differential Approaches • Inherited metabolic disorders o Macrocephaly: Canavan, van der Knaap, Alexander disease, mucopolysaccharidoses o Frontal: Alexander disease o Occipital: XLD

I Axial T2WI MR shows diffuse hyperintensity with sparing of the juxlacorlical & deep central while

=

matter E:I. Findings are typical for extensive age-related changes in this elderly gentleman.

=

Axial T2WI MR shows diffuse patchy hyperintensily in the perivenlIicular while matter due to elderly microangiopathy, a mixed eUology of arteriolosclerosis,

venous collagenosis, and amyloid.

6 35

CONflUENT

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WHITE MATTER lESIONS

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Multiple Sclerosis (lefl) Axial T2WI MR shows patchy & conlluentloci 01

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hyperintensity in the centrum

C

semiovale & atrophy. Although nonspecilic, these

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findings are characteristic

of

chronic hypertensive encephalopathy. Associated basal ganglia inlarcts &

hemorrhage are common. (RighI) Axial T2WI MR shows significant, predominantly while maller atrophy and confluent

==

periventricular

&

juxta cortical hyperintense plaques of severe chronic multiple sclerosis.

Multi-Infarct Dementia

Hypotensive Cerebral Infarction

Cerebral Amyloid Disease

Glioblastoma Multiforme

(Left) Axial FLAIR MR shows confluent

periventricular

(.~

subcortical while malter hyperintensities It] with minimal

callosal involvement

PJ::I

& significant atrophy. typical for arteriolosclerosis in this multi-infarct

dementia

patient. (RighI) Axial FLAIR MR shows confluent

linear

hyperintensity of the cortex, the subcortical "U-fibers" I<±. & diffuse white mailer hypointel1sity due to profound hypoxic encephalopathy in this child with a hypotensive event.

=

(Lefl) Axial FLAIR MR shows confluent hyperinlensilies in the periventricular while matter bilaterally & severe thinning of the involved corpus callosum PJ::I. Demyelination (callosal) & small vessel disease (periventricular)

cannot

be

differentiated from amyloid angiopathy with this pattern. (RighI) Axial PO FSf MR shows thick hyperintense periventricular signal related to diffuse ependymal spread of glioblastoma

=

I 6 36

mulliforme.

CONFLUENT

CJl

WHITE MATTER LESIONS

c: ""

HIV Encephalitis (Left) Axial T2WI MR shows diffuse cloud-like hyperintense signal throughout the centrum semiovale

~

=

with sparing of

the subcortical V-fibers due to treatment-related leukoencephalopathy. (Right) Axial FLAIR MR shows conffuent high signal I:] in the periventricular & subcortical white matter, sparing the V-fibers 81. The diffuse cortical & white malter atrophy is typically seen in lale II/V

encephalitis.

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CADASll (Left) Axial FLAIR MR shows symmetric hyperintense signal of the deep white matter 81 in this patient with EBVencephalitis. Typical imaging fealUres include symmetric T2 hyperintense signal in the basal ganglia, thalami,

cortex, &/or

brainstem. (Right) Axial T2WI MR shows diffuse abnormal hyperintense conffuent lesions throughout the white malter in the later stage of CADASIL Note the lack of atrophy despite extensive disease.

=

Metachromatic

leukodystrophy

(MlD) (Left) Axial T2WI MR shows conffuent occipital & parietal hyperintensities & volume loss due to gliosis. This distribution is classic for persistent uncontrolled neonatal hypoglycemia. (Right) Axial T2WI MR shows conffuent hyperintensity in the white matter involving the subcortical V-fibers There is normal appearing cortex & significant white maller volume loss due to MLD.

=.

I 6 37

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CONFLUENT

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WHITE MATTER lESIONS

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Canavan Disease (Left) Axial FLAIR MR shows extensive confluent hyperinlensity due to demyelination of the peritrigonal

II.]

while maller

& corpus callosum splenium in a characteristic distribution for XLD. (Right) Axial T2WI MR shows demyelination throughout

=

the entire white maller

incfuding the subcortical U-fibers in this macrocephalic Canavan

infant with

disease. MR

spectroscopy would show a characteristic

elevated

NAA

peak.

Zellweger

Van der Knaap leukoencephalopathies

(Left) Axial T2WI MR shows confluent

white maller

hyperintensity =.:I extending into gyri with small caudothalamic cysts ~ & symmetric sylvian cortical dysplasia 8l cfassic for Zellweger. (Righi) Axial T2WI MR shows white maller

hyperintensity

in

nearly all of the hemispheric white maller with partial sulcal effacement, sparing the corpus callosum suggesting mild white mailer volume expansion typical of van der Knaap leukoencephalopathy.

=

=-

ADEM (Left) Axial T2WI MR shows confluent while maller hyperintensity & atrophy =.:I with marked caudate atrophy ~ due to hypomyelination with atrophy of the basal ganglia and cerebellum (I-I-ABC). (Right) Axial T2WI MR shows poorly marginated hyperinlensily with some sparing of the subcortical U·fibers

=

in

a

patient

with

chronic ADEM. This is somewhat more symmetric than is typically seen.

I 6 38

CONflUENT

WHITE MATTER lESIONS

(Lefl) Axial T2WI MR shows marked expansion of the corpus callosum =1 cingulate & occipital gyri by innumerable clusters of CSF-signal enlarged perivascular spaces. Cyral expansion with sparing of the overlying cortex is common. (Courtesy L. Valanne, MO). (RighI) Axial T2WI MR shows confluent hyperintensity in the right temporal and parietal lobe while matter with a nearly isoinlenS€ mass ~ crossing the corpus callosum splenium.

=

Gliomatosis

Cerebri (Left) Axial T2WI MR shows patchy confluent areas of hyperintensity in the deep & subcortical white maller in a somewhat radiating pattern =1 along with some mild dilated perivascular spaces PJ:l:l. (RighI) Axial FLAIR MR shows extensive, confluent hyperintensity throughout the majority of the cerebral whiLe matter

=

with mass effect

& callosal thickening related to gliomatosis

Preservation of the underlying architecture is typical.

cerebri.

(Lefl) Axial FLAIR MR shows confluent, symmetric hyperintensity extending peripherally into the subcortical areas, a very rare manifestation of hypothyroidism known as Ilashimoto encephalopathy. (RighI) Axial T2WI MR shows a striking paLLern of edema in the cerebellar while mailer & brainstem =1 typical for maple syrup urine disease. There was relative sparing of the

=

supratentorial structures, also common in this disease.

I 6 39

THIN CORPUS CAllOSUM

DIFFERENTIAL DIAGNOSIS Common • Normal Variant • Immature Brain • Encephalomalacia • Multiple Sclerosis • White Matter Injury of Prematurity • Callosal Dysgenesis • Callosectomy/Callosotomy • Obstructive Hydrocephalus Less Common • Hypomyelination • Alcoholic Encephalopathy • Injury (Any Cause) Rare but Important • Susac Syndrome • Holoprosencephaly • Inherited Metabolic Disorders • Hereditary Spastic Paraplegia with Thin Corpus Callosum (HSP-TCC)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Diffuse corpus callosum (CC) thinning can be normal o Newborn (immature brain) • Abnormally thin CC can be inherited or acquired o Seen in many congenital malformations, inherited metabolic disorders o Check history for trauma, surgery, ischemia- infarction • Thin CC, normal signal hyperintensity o Normal variant, immature brain o Secondary to hemispheric white matter (WM) volume loss o Dysgenesis • Thin CC, abnormal signal intensity o Hypomyelination or demyelinating disease (chronic MS, Susac syndrome) o Injury (trauma, ischemia, radiation, toxic-metabolic insult) o Obstructive hydrocephalus

I 6 40

Helpful Clues for Common Diagnoses • Normal Variant o Focal thinning of corpus callosum at "isthmus" (junction between posterior body, splenium) is normal

Sagittal section slightly off-midline can make CC appear mildly thinned • Immature Brain o Hemispheric WM in newborn unmyelinated, CC thin and hypointense on TlWI o As myelination progresses, CC thickens, becomes hyperintense on Tl WI • CC splenium at 4 months • CC genu at 6 months • By 8 months CC essentially like an adult's • Encephalomalacia o Holohemispheric WM volume loss, regardless of etiology, causes diffuse CC thinning o Focal WM loss can cause focal CC thinning • Multiple Sclerosis o Look for T2/FLAIR hyperintense lesions along callososeptal interface o Ependymal "dot-dash" sign along callosoventricular border occurs early o Long-standing MS with decreased hemispheric WM volume results in thinned CC • White Matter Injury of Prematurity o CC thinning secondary to periventricular white matter infarction o Posterior CC disproportionately affected • Callosal Dysgenesis o Hypoplasia or absence of part or all of CC o CC remnants vary in size, shape o Most common abnormality associated with other malformations • Chiari 2 malformation • Heterotopias • Interhemispheric lipoma • Cephaloceles • Callosectomy/Callosotomy o History important! o Look for surgical changes of craniotomy, ventriculostomy • Obstructive Hydrocephalus o Obstructive hydrocephalus causes two kinds of CC abnormalities, stretching & intrinsic signal abnormality o As lateral ventricles enlarge, CC is stretched, appears thinned • Look for associated signal abnormality in CC (sagittal T2WI/FLAlR best) o

,.,.

THIN CORPUS CAllOSUM

CJl

c: o

Post-shunt decompression may show CC thinning, signal abnormality • Can appear bizarre, causing horizontal hyperintense "streaks" in CC on axial imaging • Can extend into periventricular WM • Theories: Impingement of CC against falx cerebri with resulting ischemia or axonal stretch

Helpful Clues for Less Common Diagnoses • Hypomyelination o Undermyelination, delayed myelin maturation o Diminished/absent WM myelination o Can be primary or secondary • Alcoholic Encephalopathy o Marchiafava-Bignami disease • Alcohol toxic to WM • Necrosis in middle layers of CC • Thinned, hypointense CC seen on T1 WI o Look for other associated abnormalities • Superior vermian atrophy • Wernicke encephalopathy • Injury (Any Cause) o Trauma (e.g., axonal injury, radiation-induced leukoencephalopathy) o Ischemia Helpful Clues for Rare Diagnoses • Susac Syndrome o

M
o

Classic triad • Encephalopathy memory loss)

(headache,

Immature

• Vision problems (retinal artery occlusions) • Hearing loss o Always involves CC • Central> callososeptal interface lesions • Middle callosal "holes" (subacute/chronic) • Holoprosencephaly o Many variants; often affect CC • Inherited Metabolic Disorders o Focal or diffuse atrophy • Focal: X-linked adrenoleukodystrophy • Diffuse: Many • Hereditary Spastic Paraplegia with Thin Corpus Callosum (HSP-TCC) o HSP-TCC is one of many hereditary spastic paraplegias • Autosomal recessive with SPGll gene mutations on chromosome 15 • Progressive neurodegenerative disorder o Clinical • Slow t spastic paraparesis • Adolescent-onset cognitive decline • Pseudobulbar dysfunction o Imaging • Thin CC (especially genu, body) with progressive atrophy • Cerebral, cerebellar atrophy often associated

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confusion,

Brain

I Sagittal T7WI MR in term infant imaged at 2 days of age shows thin corpus callosum I:'] with no discernible myelination. This is the normal appearance of an

immature, largely unmyelinated brain.

=.

Axial Tl WI MR in 32 week gestation premature

shows very thin corpus callosum genu total lack of hemispheric myelination,

infant

reflecting

6 41

THIN CORPUS

CALLOSUM

Encephalomalacia

Encephalomalacia

Encephalomalacia

Encephalomalacia

Multiple

Multiple

(Left) Axial OWl MR in a newborn shows extensive diffusion reslriction of Ihe lefl hemisphere following perinatal stroke. Acute axonal degeneration of Ihe corpus callosum 81 is present. (Right) Coronal T2WI MR al follow-up shows a large area of cystic encephalomalacia ~ and a very thin corpus callosum

81

::J

-"en

(Left) Sagittal OWl MR in a neonale wilh group B strep meningitis shows multifocal brain ischemia~. There is diffuse restriction of the corpus callosum I!:ll due 10 axonal degeneration. (Right) Sagittal T I WI MR in same child al follow-up imaging shows severe thinning

of the

corpus callosum 81.

(Left) Sagillal FLAIR MR in a leenager wilh MS shows severe atrophy

of the corpus

callosum with increased signal intensity of the corpus

callosum Sllhe seplal-callosal interface, and Ihe fornix (Right) Axial FLAIR MR shows extensive demyelinating plaques 81 in the same teen.

=.

I 6 42

Sclerosis

Sclerosis

THIN CORPUS

en

CALLOSUM

~ r::

III

:::l

Co OJ

.,

White Matter Injury of Prematurity

III

White Matter Injury of Prematurity (Left) Sagittal T1WI MR shows extreme thinning of corpus callosum in a child with cerebral palsy and history of premature birth & prolonged stay in NICU. (Right) Axial T2WI MR shows typical scalloping of the ventricles due to indentation by gray matter 81. The peritrigonal white maller is severely deficient in this same ex-premature infant with perivenlricular leukomalacia. Note relative sparing of genu

:::l

=

=.

(Left) Sagittal T1WI MR in child with Chiari 2 malformation

shows thin,

dysgenetic-appearing corpus callosum ~ (Right) Coronal T2WI MR shows severe thinning of the dysgenetic corpus callosum ~ in the same child with Chiari 2 malformation. Note absence of the leaflets of the septum pellucidum.

Callosectomy/Callosotomy

Callosectomy/Callosotomy (Left) Sagittal T2WI MR

shows absent midline corpus callosum, post-callosotomy for seizure control. Note normal cingulate gyrus 81 and pericallosal artery (Right) Corolla I T1WI MR shows a farge callosotomy defect 81 in the same child in treatment of intractable epilepsy due to Lennox-Gastaul syndrome.

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I 6 43

THIN CORPUS

C1l

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CALLOSUM

()

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Q)

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(])

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o C Q)

ro~ Cl.

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c::

.. l'Cl

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"0

c:: l'Cl

Obstructive

Hydrocephalus

(Left) Sagiltal T2WI MR in palient with long-standing aqueduclal stenosis shows thinned, stretched corpus callosum with some hyperintensity posteriorly !:.2. Note hyperdynamic CSF with "flow voids" 81. (Right) Sagittal T7 WI MR shows very thin corpus callosum III with hypomyelination, minimal T7 shortening 81 indicative of minimal myelination in the splenium. Other images showed striking lack of myelination in this 5 month old infant.

=

(Left) Sagiltal T7 WI MR in this chronic alcoholic shows thinned corpus callosum with striking hypointensity in the middle layers ffi characteristic

for

Marchiafava-Bignami

disease. (Right) Sagittal T7 WI MR shows thinned body splenium of corpus callosum following neonatal parietooccipital ischemia from combination of Hlf hypoglycemia.

=

Susac Syndrome (Left) Axial T2WI MR in the same infant reflecls sequelae

of HIE and hypoglycemia. There is extensive posterior atrophy. The genu !:.2 of the corpus callosum is norma! in size, the splenium severely atrophied 81. (Right) Sagittal FLAIR MR shows moderately thinned corpus callosum with multiple hyperintensilies, especially in the middle and posterior segments Note several middle callosal" holes" 8l characteristic for Susac

=.

I 6 44

syndrome.

THIN CORPUS CAllOSUM Ql

::l Co

OJ .., Ql

(Left) Sagittal TI WI MR shows layers of white E!ilI and gray maller comprising anterior corpus callosum in this child with semi/abar holoprosencephaly. (Right) Coronal T2WI MR shows layering of white E!ilI and gray matter in expected region of the genu of the corpus callosum in this same child with semilobar holoprosencephaly.

::l (J) C

"0 .., OJ

CD :::l

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'< 3 OJ

Inherited Metabolic Disorders

Inherited Metabolic Disorders (Left) Sagittal TI WI MR in child with urea cycle disorder shows diffuse thinning of corpus callosum, most striking in the posterior body and splenium (Right) Sagittal TI WI MR in a 10 year old with cobalamin C deficiency shows marked volume loss of the body of the well-myelinated

=.

=

corpus callosum.

This finding

and hypomyelination (mild in this child) are characteristic of this disorder.

It is important

to

consider this diagnosis, as treatment is available.

Inherited Metabolic Disorders (Left) Sagittal TI WI MR in a pre-teen boy with symptomatic X-linked

adrenoleukodystrophy shows focal thinning E!ilI and signal loss in the splenium of the corpus callosum. (Right) Axial TI C+ MR in the same child with classic X-ADL shows enhancemef1l of the leading edge of demyelination E!ilI and focal atrophy [;8 of the splenium of the corpus callosum.

I 6 45

C1l

E

ABNORMAL

SHAPE/CONFIGURATION

OF CORPUS CALLOSUM

>.r: u c

~ Q)

DIFFERENTIAL DIAGNOSIS

C1l

0..

c

~ (])

C1l 'C

o C Q)

ro~

c. ::J

(fJ C

'" "-

III

"c '"

Common • Normal Variant • Callosal Dysgenesis • Callosotomy • Neoplasm o Lipoma o Glioblastoma Multiforme o Lymphoma, Primary CNS • Decreased White Matter Volume o Hypomyelination o Periventricular Leukomalacia o HIE, Term o Cerebral Infarction, Chronic o Diffuse Axonal Injury (DAI) o Multiple Sclerosis o Radiation and Chemotherapy • Obstructive Hydrocephalus Less Common • Holoprosencephaly • Holoprosencephaly

Variants

Rare but Important • Hypertensive Intracranial Hemorrhage • Marchiafava-Bignami

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Normal corpus callosum (CC) varies in thickness, shape • Isolated callosal dysgenesis not common o Look for second lesion o Associated CNS anomalies in > 50% • Heterotopia • Cortical dysplasia • Noncallosal midline anomalies • Abnormal brainstem or cerebellum • If not congenital, history crucial!

I 6 46

Helpful Clues for Common Diagnoses • Normal Variant o Size, shape, thickness of normal CC vary • Splenium, genu are largest parts of corpus callosum • Narrowing between body, splenium ("isthmus") is normal • Dorsal surface of fully developed, normally myelinated corpus callosum often "wavy" o Immature corpus callosum is thin

• Pre-myelination • Gradually thickens with progressive myelination • Callosal Dysgenesis o One or all segments absent • Rostrum, splenium most likely deficient • Remnants vary in size, shape, configuration o "Micro" CC • Small, but well-formed • Often syndromic o "Mega"CC • Isthmus usually absent • Megalencephalic (bulky white matter) • Or small to normal brain (syndromic) • Callosotomy o Surgical disruption • Focal: Approach to 3rd ventricle or suprasellar tumor • Diffuse: Surgery for intractable seizures o Best seen on sagittal or coronal MR • Neoplasm o Can be benign/focal or malignant/diffusely infiltrating o Lipoma • 40-50% interhemispheric fissure • Common in callosal dysgenesis • Can be bulky, mass-like ("tubonodular" type, usually associated with CC agenesis; may extend through choroidal fissures into lateral ventricles) • Thin mass curving around CC body/splenium ("curvilinear" type, CC present but may be dysgenetic) o Glioblastoma Multiforme • "Butterfly" glioma • Central necrosis + thick irregular rim enhancement o Lymphoma, Primary CNS • Hyperdense on NECT • Strong, uniform enhancement o Decreased White Matter Volume • Many causes (congenital, acquired) • All may result in focal or diffuse callosal thinning o Hypomyelination • Chromosomal, inborn errors of metabolism o Peri ventricular Leukomalacia • Premature infant • "Scalloped" lateral ventricles

ABNORMAL SHAPE/CONFIGURATION

OF CORPUS CALLOSUM

(J)

c: ""

HIE, Term • Term infant with profound partial asphyxia - WM/cortex damaged o Cerebral Infarction, Chronic • Axonal loss - focal/diffuse thinning CC o Diffuse Axonal Injury (DAI) • 20% involve CC (splenium, undersurface posterior body) o Multiple Sclerosis • Chronic, late • Obstructive Hydrocephalus o Acute • Corpus callosum (CC) stretched • CC bowed upwards • Forniceal columns bowed downwards o Chronic • Post-shunt encephalomalacia • Sequela of acute callosal impingement against falx

• Middle CC body "dips" • Gray matter crosses at dip • If severe, add bilateral perisylvian polymicrogyria

o

Helpful Clues for Less Common Diagnoses • Holoprosencephaly o Corpus callosum absent in alobar • Large dorsal "cyst" often present o Semilobar may have residual splenium • Frontal fusion & hypoplasia • Splenium may be present o Lobar • Genu mayor may not be present • Gray matter often crosses with genu • Holoprosencephaly Variants o Middle interhemispheric variant • a.k.a., syntelencephaly • Splenium, genu present, body deficient

III

:J C.

CD ., III

:J (J)

Helpful Clues for Rare Diagnoses • Hypertensive Intracranial Hemorrhage o CC rare primary site • Marchiafava-Bignami o Middle-aged alcoholic o CC demyelination, necrosis, atrophy

c:

.,

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III

CD :J 8' ., III

OJ ., III :J

"U III

SELECTED REFERENCES

CD

:J

(")

].

2.

3.

4.

5.

6. 7.

8.

9.

Pierson TM et al: Mega-corpus callosum, polymicrogyria, and psychomotor retardation: confirmation of a syndromic entity. Neuropediatrics. 39(2):123-7, 2008 Samaranch Let al: SPGll compound mutations in spastic paraparesis with thin corpus callosum. Neurology. 71(5):332-6, 2008 Matar6 M et al: Functional and magnetic resonance imaging correlates of corpus callosum in normal pressure hydrocephalus before and after shunting. J Neurol Neurosurg Psychiatry. 78(4):395-8,2007 Hetts SW et al: Anomalies of the corpus callosum: an MR analysis of the phenotypic spectrum of associated malformations. AJRAm J Roentgenol. 187(5):1343-8,2006 Rollins N: Semilobar holoprosencephaly seen with diffusion tensor imaging and fiber tracking. AJNR Am J Neuroradiol. 26(8):2]48-52, 2005 Kinsman SL: White matter imaging in holoprosencephaly in children. CUff Opin Neurol. ] 7(2):1 ]5-9,2004 Barkovich AJ et al: Callosal agenesis with cyst: a better understanding and new classification. Neurology. 56(2):220-7,200] Kier EL et al: The normal and abnormal genu of the corpus callosum: an evolutionary, embryologic, anatomic, and MR analysis. AJNR Am J Neuroradiol. 17(9):1631-41, 1996 Mendelsohn DB et al: Corpus callosum lesions after closed head injury in children: MR], clinical features and outcome. Neuroradiology. 34(5):384-8, 1992

Normal Variant

::r

'< 3

III

Normal Variant

Sagittal Tl WI FSMR with a close-up view of the corpus callosum shows normal "wavy" dorsal surface. Note the focal thinning along posterior body a common normal finding.

=-

=-

Sagittal TlWI MR shows a normal neonatal corpus callosum thin due to age-appropriate lack of myelin maturation. The cingulale gyrus ~ is normal.

I 6 47

ABNORMAL

Cll

E

:>.

.<: () c
~ Cll

a.. c Cll ~ co Cll

·C

o C
"§ a. :J

CIJ

C nl

•... co "t:l C nl

:J

(Left) Sagiltal T1 WI MR shows callosal agenesis. Note radial array of

paracentral gyri "pointing" 10 the Jrd ventricfe as well as absence of identifiable cingulate gyrus. Hippocampal

commissure

is

visualized posteriorly 81. (Right) Coronal r2WI MR shows the absence of crossing callosal fibers, the presence of Probst bundles and vertical hippocampi

a

~

-'"

(f)

(Left) Sagiltal T1WI MR shows only a residual genu IJ:.:I of the corpus callosum, with absence of the body and splenium and truncation of the rostrum. (Right) Sagittal TlWI MR shows absent rostrum, small deformed genu, thick body and absent splenium in this child with Chiari 2. Note

a

=-=

prominent

massa inlermedia

inferiorly beaked tectum and caudally displaced 4th ventricfe.

(Left) Sagiltal T1WI MR in a child with severe microcephaly shows a short, thick corpus callosum =:I. Note the normal

narrowing

(isthmus) at junction of body; splenium is absent Actual callosal volume is small. (Right) Sagittal T2WI MR shows focal defect at the junction

of the genu and

body of the corpus callosum the site of surgical approach to this child's suprasellar tumor

a

=.

I 6 48

SHAPE/CONFIGURATION

OF CORPUS

CALLOSUM

ABNORMAL

SHAPE/CONFIGURATION

OF CORPUS

en ;K"

CALLOSUM

c: Ql

::I Q.

III ., Ql

(Left) Sagiltal T1 WI MR shows a large midline lipoma and a small remnant of the body SlI of the corpus callosum. (Right) Coronal T1 C+ MR shows classic "bullerfly" glioblastoma multi/orme of the corpus callosum Central necrosis with an irregular rind of enhancing tumor is typical.

=.

::I (JJ

c:

"0 ., Q)

co::I S ., 00' OJ ., Q)

:J lJ Q)

., CO

::I

o ::T

'<

3 Q)

(Left) Axial T1 C+ MR shows primary CNS lymphoma involving splenium of the corpus callosum. Gadolinium enhancement shows avid, solid enhancement of splenial tumor

& extension

into

adjacent parenchymal white mailer. (Right) Sagittal T1 WI MR shows marked callosal thinning SlI & atrophy in a child whose hydrocephalus follows unilateral grade 4 intravenlricular hemorrhage.

Posteriorly there is more severe callosa! volume loss ~.

Periventricular leukomalacia

Cerebral

Infarction,

Chronic (Left) Axial T2WI MR in the same child shows marked 1055 of periventricular white matter, septal destruction, & focal porencephaly ~ at site of prior grade 4 hemorrhage. Posterior white maller IOS5 correlates with focal CC atrophy. (RighI) Sagillal T1 WI MR shows focal thinning SlI of body & splenium of corpus callosum, following neonatal parietooccipital ischemia & gliosis from combination of hypoxic ischemic encephalopathy & hypoglycemia.

I 6 49

ABNORMAL

ell

E

SHAPE/CONFIGURATION

OF CORPUS

CALLOSUM

>.

.<::

()

c [I:' ell

Cl..

Cerebral

C

~

en

ell

'C

.8 c (I)

ro~ a.

::J CfJ

C ell

Infarction,

Chronic

Diffuse

Axonal Injury

(DAI)

(Left) Coronal T2WI MR shows parietal ulegyria E!lI and marked thinning of the corpus callosum allhe psalterium (Right) Sagillal T1WI MR shows swelling and signal loss of the expected region of the isthmus E!lI of the corpus callosum due 10 shear injury.

'-=.

'!Xl "0

c ell

::J

-"en

Multiple

Sclerosis

(Left) Axial rLAIR MR shows abnormal signal of crossing callosal fiber tracts

'-=

fo/Jowing traumatic

shear

injury. (Right) Sagillal FLAIR MR shows multiple hyperintense foci in the corpus callosum as well as a large pontine lesion E!lI. The isthmus (posterior body) of CC is thinned more than normally because of axonal loss from multiple centrum semiovale lesions.

=

Radiation and Chemotherapy (Left) Sagillal T1 WI MR shows diffuse thinning E!lI of the rostrum, genu, and body of the corpus callosum following treatment for ALL. (Right) Sagillal T2WI MR shows mild stretching and thinning of the corpus callosum due to hydrocephalus. There is obstruction of the aqueduct of Sylvius by a tectal glioma

Ii8

I 6 50

Obstructive

Hydrocephalus

ABNORMAL SHAPE/CONFIGURATION

OF CORPUS CAllOSUM

CJl

c: " III

::::J Co

...

OJ III

(Left) Sagillal T2WI MR shows the absence of corpus callosum. White mailer S'I traverses the midline, although not in compact bundle form. There is a large dorsal cyst. Note the lack of vermian primary fissure due

to associated rhombencephalosynapsis. (RighI) Axial T1WI MR shows the lack of midline fissure. White maller ~ is in continuity along the midline. 8asal ganglia S'I approximate each other.

::::J

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...OJ

1:>

CD OJ

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OJ OJ

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(Lefl) Sagillal T1WI MR shows both white, gray maller H2 crossing midline anterior and posterior to "dip" PJ:!.:I in CC where only

gray matter traverses. This is a middle interhemispheric variant (synte/encephaly). (Right) Axial TI WI MR in the

same case shows gray·white maller traversing together H2 in the expected location of splenium. Gray matter protrudes ~ into ventricular system. Septum pellucidum is absent

(Lefl) Axial NECT shows extensive hemorrhage into the genu and splenium of the corpus calfosum, with extension along the septal leaflets PJ:!.:I and into the ventricles in this child following cardiac transplant. (Right) Sagittal FLAIR MR shows linear bright signal at the callososeptal interface demyelination of the splenium 8l and an otherwise generally thin corpus callosum.

=-

I 6 51

co

CORPUS CAllOSUM

E

>.r: u c OJ

~ co

a.. c

co ~

co co

'C

o C OJ

ro~ 0..

:J (f) C

co ~

III "C

c co :J

-"en

DIFFERENTIAL DIAGNOSIS Common • Multiple Sclerosis • Diffuse Axonal Injury (DAI) Less Common • Post-Surgical • ADEM • Obstructive Hydrocephalus • Lacunar Infarction Rare but Important • Enlarged Perivascular Spaces • Marchiafava-Bignami Disease • Susac Syndrome

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Multiple Sclerosis o Callososeptal interface T2 hyperintensities o "Burned out" chronic lesions have Tl hypointense center, very slight hyperintense rim (lesion within lesion) • Diffuse Axonal Injury (DAI) o Punctate hemorrhages at gray-white interfaces & corpus callosum (CC) typical o "Blooming" on T2*, GRE, SWI common o May result in focal encephalomalacia Helpful Clues for Less Common Diagnoses • Post-Surgical o Small CC "holes" common after shunt o Defects may result from transcallosal surgery (e.g., for colloid cyst)

HOLES

• ADEM o Both subcortical white matter (WM), deep gray nuclei often involved o May mimic multiple sclerosis • Obstructive Hydrocephalus o Dorsal, middle layers may show Tl hypointense & T2 hyperintense signal o May be related to CC compression against falx during acute ventricular obstruction • Lacunar Infarction o Uncommon; rich blood supply to CC o Focal ischemia with surrounding gliosis o Supplied by anterior communicating artery, peri callosal artery, & posterior pericallosal artery Helpful Clues for Rare Diagnoses • Enlarged Perivascular Spaces o Follow CSF on all sequences o When CC involved, adjacent brain often involved • Marchiafava-Bignami Disease o Rare complication of chronic alcoholism; CC demyelination & necrosis o T2 hyperintense CC (middle layers) virtually pathognomonic o Sudden onset of altered mental status, seizures, dysarthria, ataxia, hypertonia, pyramidal signs • Susac Syndrome o Classic clinical triad = encephalopathy, visual changes, hearing loss o Multifocal supratentorial WM lesions + CC o "Holes" in CC middle layers characteristic

Diffuse Axonal Injury (DAI)

I 6 52

Sagittal Tf WI MR shows mulUple hypointense lesions in U,e CC & deep white mailer perpendicular to the lateral ventricle in this young adult. These lesions may have a mildly hyperintense rim.

=

Sagittal T2' eRE MR shows muMocal hypointensilies at the gray-white interfaces & CC related to OAi. The CC lesion will likely result in focal encephalomalacia, causing a "ce hole".

CORPUS

CALLOSUM

HOLES III

::l

a. III ., Obstructive

ADEM

III

Hydrocephalus (Left) SagiLtal FLAIR MR shows multifocal hyperintensiLies within the CC & pons in this ADEM patient with a recent flu-like illness. Imaging mimics MS. These lesions often result in "CC holes" chronically. (Rigl1t) Axial T2WI MR

shows a peculiar transverse "striated" appearance of the CC body resulLing from

prior severe obstructive hydrocephalus. In about 15% of patients with shunted hydrocephalus, CC signal abnormalities may be

::l

en c

-0

., Q)

CD

~

o:0. Q)

OJ ., Q)

~ -U Q)

~ CD ~ ()

::T

'< 3 Q)

seen.

(Left) SagiLtal T1 WI MR shows a CC hole Il::l related to

a

lacunar

infarct in

a

moyamoya patient. Note the T1 shortening related to additional anterior circulation ischemia. Lacunar infarcts are uncommon as there is a rich CC blood supply. (Right) Sagittal T1 WI MR shows mulLiple "cysLic" lesions that follow CSF in the CC & cingulate gyrus. When perivascular spaces are in the CC, there is often involvement of the adjacent brain, cingulate gyrus in this case.

Marchiafava-Bignami

Disease

Susac Syndrome (Lelt) Sagittal T1WI MR shows cla.5sic findings (or Marchiafava-Bignami disease with a thinned CC & hypoinlensily in the middle layers l:llI. NOle that the genu, body, & splenium are all involved. T2 hyperintensity that extends to the deep white matter is also common. (Right) SagiLtal T2WI MR shows a

subtle hyperintense" hole" in the central CC l:llI in this young adult with Susac syndrome. Iioies in the middle layers of the CC are characteristic.

I 6 53

co

CORPUS CAllOSUM

E

lESION WITHOUT MASS EFFECT

>. .£ l)

C

DIFFERENTIAL DIAGNOSIS

~ Q)

co

0-

c

co ~

CD

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en c

co ~

co

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Common • Multiple Sclerosis • Diffuse Axonal Injury (DAI) less Common ·PML • ADEM • Periventricular Leukomalacia Rare but Important • Enlarged Perivascular Spaces • Vasculitis • Lyme Disease • Susac Syndrome • X-Linked Adrenoleukodystrophy • Metachromatic Leukodystrophy (MLD)

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Multiple Sclerosis o Multiple perpendicular callososeptal T2 hyperintensities characteristic o Corpus callosum (CC) almost always involved, subcallosal striations early • Diffuse Axonal Injury (DAI) o Punctate hemorrhages at corticomedullary junction & CC typical o CC involvement in 20%; 75% involve splenium/undersurface of posterior body Helpful Clues for less Common Diagnoses

·PML o

I 6 54

Bilateral, asymmetric involvement typical

Large multifocal subcortical white matter (WM) lesions without mass effect • ADEM o 10-14 days after viral illness/vaccination o Involves subcortical WM, deep gray nuclei o May mimic multiple sclerosis • Periventricular Leukomalacia o Small CC typical, ± T2 hyperintensity o Peritrigonal WM loss & "wavy" ventricular margins o

Helpful Clues for Rare Diagnoses • Enlarged Perivascular Spaces o Cystic lesions follow CSF on all sequences o May involve CC • Vasculitis o Subcortical WM commonly affected o DWI bright & enhancement typical • Lyme Disease o May mimic multiple sclerosis o Cranial nerve enhancement common • Susac Syndrome o Classic triad: Encephalopathy, retinal artery branch occlusions, hearing loss o Multifocal supratentorial WM lesions + CC • X-Linked Adrenoleukodystrophy o Enhancing peritrigonal demyelination o Involves CC splenium early, followed by peritrigonal WM & WM tracts • Metachromatic Leukodystrophy (MLD) o Confluent "butterfly-shaped" cerebral hemisphere WM T2 hyperintense signal o Late involvement of CC, V-fibers, pyramidal tracts, internal capsule

Multiple Sclerosis

Diffuse Axonal Injury (OAf)

Sagittal fLAIR MR shows mu/tjfocal hyperinlense lesions wilhin the CC & sulx:orlical while mailer. typical {or MS. Sagillal FLAIR MR helps idenlily sulx:allosal

Sagiual T2WI MR shows hyperinlensily in lhe CC body & local hypoinlensily in lhe splenium E!ilI relaled 10 OAI. Correialion with eRE or SWI sequences lypically shows mulliple addilionallesions.

=

striations seen in early disease stages.

=

CORPUS

CALLOSUM

LESION WITHOUT

,.-c:

MASS EFFECT

(J)

'a.:"l ...

OJ (Left) Axial FLAIR MR shows confluent, high signal in the frontal lobes that crosses the CC without significant mass effect.

There is involvement

of the subcortical U-fibers, typical of PML. No enhancement is characteristic. (Right) Axial T2WI MR shows a "wavy" ventricular

margin

m& a

small corpus callosum, typical of PVL. Note also perilrigonal while matter 1055 & deep sulci. PVL often occurs in premature

infanl5

related to a hypoxic-ischemic

':"l (J)

c:

... m :l o...

"0 Ql

iii'

...

OJ Ql

:l

lJ

...

Ql

CD :l (")

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event

(Left) Axial T2WI MR shows innumerable clusters of CSF-signal cysts in the corpus callosum & occipital white matter related to perivascular spaces. These are rare in the corpus callosum. (Right) Sagittal FLAIR MR shows hyperintensities in the middle layers of the CC, typical of Susac syndrome. Central CC involvement is more common than callososeptal interface involvement.

Imaging

may

mimic MS, so clinical history is important for diagnosis.

(Left) Axial FLAIR MR shows marked hyperintensity in the CC splenium & peritrigonal white maller related to demyelination

in this patient

with X-ALD. CC splenium is involved early. Enhancement is cfassic. (Right) Axial T2WI MR shows confluent hyperintense periventricular white matter~ (butterfly pattern) related to demyelination. Note the preservation of subcortical U-fiber myelination SlI. Hyperintensity & volume loss of the

CC is common.

I 6 55

ro

CORPUS CAllOSUM

E

MASS

>L U C Q) L

ro CL

c ro L

co ro

·C

o C Q)

ro L

Cl.

::J (/J

C

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DIFFERENTIAL DIAGNOSIS Common • Glioblastoma Multiforme • Lymphoma, Primary C S • Anaplastic Astrocytoma less Common • Oligodendroglioma • "Tumefactive" Multiple Sclerosis • Gliomatosis Cerebri • Lipoma Rare but Important • "Tumefactive" ADEM • Enlarged Perivascular Spaces

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Glioblastoma Multiforme o Heterogeneously enhancing mass o Classically crosses corpus callosum (CC), results in a "butterfly glioma" o Central necrosis, blood products typical • Lymphoma, Primary CNS o Homogeneously enhancing, 1'2 hypointense mass o Usually involves basal ganglia, periventricular white matter (WM) o Often crosses CC, extends along ependymal surfaces • Anaplastic Astrocytoma o 1'2 hyperintense WM mass with variable enhancement

Glioblastoma

o

Often involves, crosses CC

Helpful Clues for less Common Diagnoses • Oligodendroglioma o Calcified frontal lobe mass involving cortex/subcortical WM o May extend into CC o Heterogeneous enhancement 50% • "Tumefactive" Multiple Sclerosis o CC lesions characteristic o Single tumefactive lesion common o Often incomplete, "horseshoe-shaped" enhancement, open toward cortex • Gliomatosis Cerebri o 1'2 hyperintense infiltrating mass with enlargement of involved structures o May cross CC o Typically nonenhancing at presentation • Lipoma o Often associated with CC dysgenesis o 1'1 hyperintense mass along CC Helpful Clues for Rare Diagnoses • "Tumefactive" ADEM o 10-14 days after viral illness/vaccination o Often involves subcortical WM & deep gray nuclei o Incomplete ring enhancement characteristic • Enlarged Perivascular Spaces o May cause mass effect, particularly in midbrain o Follow CSF signal on all sequences o No enhancement

Multiforme

lymphoma,

Primary eNS

I 6

T1

mass

involving

perialfial

56

C+ M R

Axial

while

shows

the

a

corpus

maller.

helerogeneously callosum

Cenlfaf

of these malignanllumors.

necrosis

enhancing

splenium

& left

is characteristic

Axial

T1 C+ MR shows

a homogeneously

enhancing

mass involving t.he corpus callosum splenium perialrial hypointense

while

malter.

&, enhances

Lymphoma homogeneously.

is

typically

& T2

CORPUS CALLOSUM MASS

CJl

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Anaplastic

Astrocytoma (Left) Axial FLAIR MR shows a hyperintense mass that involves the corpus callosum splenium & parietal lobes. Anaplastic astrocytomas occur in hemispheric

white

malter, and neoplastic cells are almost always found beyond the signal abnormality. (Right) Axial T2WI MR shows a heterogeneous frontal lobe mass that involves the corpus callosum genu, cortex, & subcortical white matter. These tumors are typically calcified, which is

OJ

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ii3

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3 Ql

often better seen on CT.

"Tumefactive"

Multiple

Sclerosis

Gliomatosis

Cerebri (Left) Axial FLAIR MR shows marked

while maller

hyperintensity I:j] with extension into the corpus callosum. There is a central hypointense mass causing mass effect on the adjacent ventricle. Enhancement was an incomplete ring, typical (or demyelination. (Right) Axial FLAIR MR shows extensive hyperintensity in the white matter with involvement of the corpus callosum genu & splenium. Gliomatosis cerebri at biopsy. Bilateral involvement

is common.

(Left) Sagittal T1 WI MR shows a fat-intensity

lesion

I:j] in the interhemispheric fissure, wrapping

around

the

mildly hypoplastic corpus callosum. The lipoma also extends anteriorly along the interhemispheric fissure to involve the fronlallobes ~. (Right) Sagiltal TI WI MR shows marked expansion of the corpus callosum, cingula Ie, & occipital gyri by innumerable clusters of CSF-signal cysts, perivascular spaces. Involvement of the corpus callosum is rare.

I 6 57

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Common • Diffuse Axonal Injury (DAI) • Multiple Sclerosis • Status Epilepticus • Drug Toxicity, NOS Less Common • Transient Metabolic Derangement • Encephalitis (Miscellaneous) • Hypoxic-Ischemic Encephalopathy, • Alcoholic Encephalopathy • Neoplasms ·PML • Hypoglycemia Rare but Important • X-Linked Adrenoleukodystrophy • Acute Hypertensive Encephalopathy, • ADEM • White Matter Disease with Lactate • Enlarged Perivascular Spaces • Systemic Lupus Erythematosus

NOS

PRES

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Corpus callosum (CC) has 4 named parts: Rostrum, genu, body, & splenium • Splenium is most likely portion to be affected by various pathologies o Possibly related to posterior pericallosal artery vascular supply • Splenium lesions may have similar imaging appearance, history often key to diagnosis • Many etiologies may cause a reversible T2 hyperintense lesion o Pathophysiology for reversible lesions is thought to be cytotoxic edema

I 6 58

Focal splenium lesion less common CC almost always involved, callosal striations seen early o May have characteristic incomplete ring or horseshoe enhancement • Status Epilepticus o T2 hyperintensity in supratentorial gray matter &/or subcortical white matter (WM) with mild mass effect typical o May focally involve hippocampus or CC splenium • Drug Toxicity, NOS o Multiple drugs have been associated with a reversible splenium lesion • Anti-epileptic agents, metronidazole, sympathomimetic-containing diet pills o Focal T2 hyperintensity, DWI positive o Metronidazole encephalopathy may also affect dentate, brainstem, & WM o

DIFFERENTIAL DIAGNOSIS

Helpful Clues for Common Diagnoses • Diffuse Axonal Injury (DAI) o Punctate hemorrhages at gray-white interfaces, corpus callosum (CC), deep gray matter, & upper brainstem typical o CC involved in 20%; 75% involve splenium & undersurface of posterior body o T2*/GRE & SWI typically shows multiple additional lesions • Multiple Sclerosis o Callososeptal T2 hyperintensities characteristic

Helpful Clues for Less Common Diagnoses • Transient Metabolic Derangement o Focal T2 hyperintense splenium lesion, DWI positive o Typically reversible • Encephalitis (Miscellaneous) o Multiple infectious agents may cause focal T2 hyperintense splenium lesion • Influenza type A, rotavirus, E. coli, measles, mumps, adenovirus, herpes, varicella, EBV, West ile, salmonella o Typically reversible & DWI positive • Hypoxic-Ischemic Encephalopathy, NOS o Most common in deep gray nuclei o DWI positive acutely o Focal splenium lesion less common • Alcoholic Encephalopathy o Marchiafava-Bignami: Sudden onset of altered mental status, seizures, dysarthria, ataxia, hypertonia, pyramidal signs • T2 hyperintense CC (middle layers) virtually pathognomonic o Toxic leukoencephalopathy with demyelination, rare complication, often involves splenium & peri ventricular WM o Superior vermian atrophy common • Neoplasms o Lymphoma & glioblastoma (GBM) classically cross CC splenium or genu o Enhancing WM mass with CC extension o Lymphoma: Homogeneous enhancement o GBM: Heterogeneous enhancement

CORPUS

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·PML o Occurs in immunosuppressed or immunocompromised patients o T2 hyperintensity in subcortical & deep WM, crosses ee splenium & genu o Involves subcortical V-fibers • Hypoglycemia o Severe parietooccipital edema &/or infarcts in a newborn o T2 hyperintensity in occipital & parietal lobes; commonly affects splenium o DWI positive o May be reversible if treated early Helpful Clues for Rare Diagnoses • X-Linked Adrenoleukodystrophy o Enhancing peritrigonal WM demyelination o Splenium involved early followed by peri trigonal WM & other WM tracts (corticospinal tracts/forn ix/ comm isural fibers/visual and auditory pathways) o Typically spares subcortical V-fibers • Acute Hypertensive Encephalopathy, PRES o Reversible WM edema induced by hypertension o Typically affects cortex & subcortical WM of parietal & occipital lobes o Posterior circulation o Rarely affects splenium • ADEM o Subcortical WM & deep gray nuclei commonly involved

Diffuse Axonal Injury (DAI)

May focally involve splenium o Typically multiple lesions • White Matter Disease with Lactate o Van der Knaap leukoencephalopathy subtype o Diffuse periventricular, deep cerebral WM T2 hyperintensity + spinal involvement o Posterior ee & posterior limb of internal capsule involved o Positive lactate peak • Enlarged Perivascular Spaces o May occur throughout ee o Follow eSF on all MR sequences o When present in ee, adjacent brain often involved • Systemic Lupus Erythematosus o May cause focal lesion in splenium related to vasculitis o

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Alternative Differential Approaches • Reversible splenium lesions o Status epilepticus, drug toxicity, transient metabolic derangement, encephalitis, hypoglycemia, PRES • Splenium lesions in a child o DAI, status epilepticus, drug toxicity, encephalitis, HIE, hypoglycemia, ALD, ADEM, WM disease with lactate, perivascular spaces • Splenium lesions in an adult o DAI, status epilepticus, drug toxicity, encephalitis, alcoholic encephalopathy, neoplasms, PML, PRES, ADEM, perivascular spaces

Multiple Sclerosis

I Axial T2WI MR shows focal hyperintensity in the CC

Axial T7 C+ MR shows a tumefactive multiple sclerosis

splenium P.t] related to OAf. OWl is often positive in acute OAi. T2*/CRE & SWI sequences often show

(MS! plaque that extends into the splenium. The incomplete ring of enhancement P.:JJ is characteristic of demyelination. The CC is almost always involved in MS.

multiple additional lesions.

6 59

CORPUS

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Status Epilepticus (Left) Sagittal T2WI MR shows focal hyperintensity in the CC splenium =::lI caused

by transient slaWs epilepticus. Acutely this lesion is OWl positive & typically resolves completely. (Right) Sagittal T2WI MR shows hyperinlensily throughout the spleniurn

with

extension

into

the body

of the CC in this patient with renal failure & electrolyte imbalance. These MR findings are usually completely reversible. Enhancement is rarely

present

(Left) Axial T2WI MR shows focal hyperintensity in the CC splenium P:J:I related to

an Epstein-Barr virus infection.

This reversible

lesion does not enhance. (Right) Axial OWl MR shows focal restriction in the splenium in this patient with viral encephalitis. The patient's symptoms & MR findings completely resolved, as is typical of this process. Imaging mimics status epileplicus,

anti-epileptic

medica lion toxicity. early Marchiafava-Bignami

disease,

& acute ischemia.

(Left) Axial fLAIR MR shows subtle focal hyperintensity in the CC splenium E!i:I related to West Nile virus encephalitis. West Nife virus typically involves the deep gray nuclei & brainstem. (Right) Axial T2WI MR shows focal a ute ischemia in the CC splenium E!i:I of this 2 year old related to a

morphine overdose. Note

I 6 60

subtle hyperintensity in the basal ganglia. Involvement of the deep gray nuclei is common in hypoxic·ischemic encephalopathy.

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Encephalopathy (Left) Sagittal T2WI MR shows focal hyperintensity in the central CC splenium related to early Marchiafava-Bignami disease. This disease often affeclS the body & splenium of lhe Cc. Involvement of the middle layers of the CC is virtually pathognomonic. (Right) Axial T1 C+ MR shows enhancement in the splenium & forceps major of the CC ~ as well as the perivenlricular

while matter

related to acute demyelination from severe alcohol poisoning.

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(Left) Axial T1 C+ MR shows diffuse enhancement in the splenium of lhe CC related 10 primary CNS lymphoma. This tumor classically crosses lhe CC & spreads along the ependyma. Extension to the adjacent

while matter is

lypical. (Right) Axial T2WI MR shows hyperintenshy in the CC splenium & perivenlricular

while maller

in this immunosuppressed patient. PML lypically does not enhance. involvement

Note of the

subcortical U-fibers, characteristic of PML.

(Left) Axial FLAIR MR shows focal increased

signal

intensity in the splenium of the CC =::I related to demyelination in early X-ALD. This typically

progresses to involve the forceps major of the CC & adjacent

white matter. Bone

marrow transplant may help to prevent progression of the disease. (Right) Sagittal FLAIR MR shows a focal hyperintense lesion in the splenium in this young patient with a recent viral illness. ADEM often mimics MS, as in this case.

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I 6 61

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BASALGANGLIA CALCIFICATION

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DIFFERENTIAL DIAGNOSIS Common • Aging Brain, Normal • eurocysticercosis less Common • Fahr Disease • Hypoxic-Ischemic Injury, NOS • MELAS • Congenital Infections o HIV, Congenital o CMV, Congenital • Endocrinologic Disorders o Hyperparathyroidism o Hypoparathyroidism o Pseudohypoparathyroidism o Pseudopseudohypoparathyroidism o Hypothyroidism • Toxoplasmosis, Acquired • Leigh Syndrome • Tuberculosis • Radiation and Chemotherapy • Cavernous Malformation (Mimic) • Vascular Calcification (Mimic) • Tuberous Sclerosis Complex (Mimic) Rare but Important • Hallervorden-Spatz Syndrome • CO Poison ing • Parasites, Miscellaneous

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Basal ganglia (BG) Ca++ is end result of multiple toxic, metabolic, inflammatory, and infectious insults • Location of Ca++ helpful to determine underlying cause (globus pallidus [GP] vs. putamen vs. caudate) • Patient age may impact differential diagnosis

I 6 62

Helpful Clues for Common Diagnoses • Aging Brain, Normal o Commonly affects GP more than putamen o Seen in aging brain as normal variant o Typically in patients older than 30 years o If occurs with other Ca++, consider pathologic condition • Neurocysticercosis o May occur anywhere in brain

o

• Convexity subarachnoid spaces most common Imaging varies with pathologic stage • Ca++ in nodular calcified (healed) stage

Helpful Clues for less Common Diagnoses • Fahr Disease o Bilateral symmetric BG Ca++, often with Ca++ in other locations o GP is most common site of Ca++ (lateral> medial) o Other locations: Putamen, caudate, thalami, dentate nuclei of cerebellum, cerebral white matter, internal capsule o Associated abnormalities: Parkinsonism in autosomal dominant FD • Hypoxic-Ischemic Injury, NOS o HIE, term: Profound acute injury results in decreased BG and thalamic density, ± hemorrhage acutely • Lateral thalami and posterior putamen typical • May show Ca++ in chronic phase o HIE in adults: Putamen> GP typically • May have history of "anoxic event" • MR > CT for acute changes • May show Ca++ in chronic phase • MELAS o BG Ca++ in child or young adult with cortical lesions (parietooccipital > tem poroparietal) • HIV, Congenital o Symmetric BG Ca++ and cerebral atrophy • GP and putamen> caudate o Subcortical WM Ca++ common o Ca++ occur in a fairly symmetric fashion a result of a calcific vasculopathy of medium and small arteries • CMV, Congenital o Periventricular Ca++, microcephaly, and cortical dysplasia characteristic o Periventricular > > BG Ca++ • Endocrinologic Disorders o Bilateral BG: GP and putamen, dentate nuclei, thalami, subcortical areas o Ca++ in primary hypoparathyroidism is more diffuse than in other etiologies of Ca++ • Toxoplasmosis, Acquired o Typically multifocal, but BG common site (up to 75%) o Enhancing lesion most common acutely

BASAL GANGLIA

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CALCIFICATION

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Post-therapy, Ca++ is common Leigh Syndrome o Bilateral, symmetric t T2/FLAIR putamina and peri-aqueductal gray matter o Putamen> caudate> GP, Ca++ when chronic Tuberculosis o Typically causes tuberculous meningitis &/or localized CNS infection, tuberculoma o Approximately 20% of tuberculomas calcify Radiation and Chemotherapy o Mineralizing microangiopathy causes BG and subcortical WM Ca++, atrophy o Mineralizing microangiopathy common with chemotherapy and XRT o Typically occurs 2 or more years after XRT Cavernous Malformation (Mimic) o Hyperdense mass (Ca++ and blood products) may occur in any location Vascular Calcification (Mimic) o May relate to physiologic vascular calcification, atherosclerosis, aneurysm, or vascular mass Tuberous Sclerosis Complex (Mimic) o Subependymal nodules are typically calcified; occur along caudothalamic groove, peri ventricular o

•

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•

•

Helpful Clues for Rare Diagnoses • Hallervorden-Spatz Syndrome o Rare neurodegenerative disorder with brain iron accumulation

T2 MR characteristic: High signal within bilateral GP with surrounding low signal, "eye of the tiger" o CT may show mineralization in GP • CO Poisoning o Typically hypodense, symmetric GP on CT, T2 hyperintense o GP Ca++ occurs as end result • Parasites, Miscellaneous o Amebic encephalitis: Supratentorial, frontal lobes and basal ganglia • Typically enhancing lesions acutely, may calcify in chronic phase o Malaria: Predilection for BG, cortex • Hemorrhage, infarcts and cerebral edema • May show Ca++ in chronic phase o Paragonimiasis: Acutely often hemorrhage or infarct, followed by Ca++ granulomas o

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Alternative Differential Approaches • BG Ca++ in a child o Mitochondrial encephalopathies: MELAS, MERRF,Leigh syndrome o Congenital infections: HIV, CMV o HIE, term o Associated with Down syndrome o Aicardi-Goutieres syndrome (pseudo-TORCH) o Cockayne syndrome o Long-term complications of radiation therapy for childhood brain tumors and intrathecal chemotherapy

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Axial NECT shows typical basal ganglia calcification in this 75 year old male who presented after minor trauma. Note location within the globus pallidus, typical for

Axial CECT shows a calcified left putamen nodule that represents the nodular, calcified (healed) stage of NCe. Note right external capsule cyst with central "dot"

normal aging brain.

representjng a scolex.

6 63

BASAL GANGLIA

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(Left) Axial NECT shows typical CT appearance of Fahr disease with extensive calcifications present in the basal ganglia, cerebral white matler, and at subcortical gray-white junclions. (Right) Axial NECT shows calcification of thalami and BC ~ from stalus marmQratus. There is atrophy and a collapsed calvarium fof/owing remote mixed HIE. Profound acute HIE typically affects Be.

(Left) Axial NECT shows calcificalion of globus pallidus bilaterally I:?] in this child Note low density in medial occipital lobes related to ischemia.

BC calcification

is abnormal in children and young adults. (Right) Axial NECT shows symmetric BC calcification with scattered foci of subcortical calcification. Note typical involvement

of lentiform

nuclei greater than caudate heads.

(Left) Axial NECT shows

peri ventricular and basal ganglia calcifications. Periventricular calcifications, venlriculomegaly, and microcephaly strongly suggest congenital CMV infection. (Right) Axial NEeT shows diffuse hyperdense calcifications within the basal ganglia, thalami, and subcortical white matter. Calcification related to systemic disease is typically

symmetric.

I 6 64

CALCIFICATION

BASAL GANGLIA

CALCIFICATION III

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(Lefl) Axial CECT shows an enhancing Be mass 111 in an AIDS patient. Post-lherapy, enhancing lesions typically calcify. Be is the most common

location

followed

by thalamus, then hemispheres. (RighI) Axial T2WI MR shows symmetric T2 hyperintensity in the basal ganglia E±I bilaterally in this child with

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Radiation and Chemotherapy

Vascular Calcification

(Mimic) (Lefl) Axial NECT shows mineralizing

microangiopathy related to radiation therapy and chemotherapy for a posterior fossa medulloblastoma. Note symmetric Ca++ in Be and subcortical while maller. (RighI) Axial NECT shows intracranial atherosclerotic disease with extensive

Ca++

in internal carotid and middle cerebral arteries I:] which

mimics

Be

Ca++.

Posterior fossa aneurysm is partially visible.

Hallervorden-Spatz

Syndrome (Left) Axial NECT shows calcified subependymal nodules

in the foramen

of

Monro region bilaterally in this child with seizures, mimicking Be Ca++. S[N occur in 98% of patients with tuberous sclerosis. (RighI) Axial NECT shows mineralization in CP bilaterally related to iron accumulation in a patient

with pantothenate kinase-associated neurodegeneration (PKAN); look for "eye of the tiger" on T2 MR.

I 6 65

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11 HYPERINTENSE

DIFFERENTIAL DIAGNOSIS Common • Physiologic Calcification, Brain • Neurofibromatosis Type 1 • Hepatic Encephalopathy • Hyperalimentation Less Common • Hypoxic-Ischemic Encephalopathy, NOS o HIE, Term o Hypotensive Cerebral Infarction • CO Poisoning • Kernicterus • Wilson Disease Rare but Important • Endocrine Disorders o Hypothyroidism o Hyperparathyroidism o Hypoparathyroidism o Pseudohypoparathyroidism o Pseudopseudohypoparathyroidism • Hypoglycemia • Hallervorden-Spatz Syndrome • Fahr Disease • Encephalitis (Miscellaneous) o Japanese Encephalitis o HIV, Congenital

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Basal ganglia (BG) are paired deep gray nuclei & include caudate nuclei, putamen, & globus pallidus (GP) • Lentiform nucleus: Putamen & GP • Corpus striatum: Caudate, putamen, & GP • BG Tl hyperintensity is usually symmetric, related to calcification (Ca++) or other mineralization

I 6 66

Helpful Clues for Common Diagnoses • Physiologic Calcification, Brain o Commonly affects GP more than putamen o Seen as normal variant in aging brain o Typically in patients older than 30 years • Neurofibromatosis Type 1 o Focal areas of increased signal intensity (FASI)characteristic, T2 hyperintense o FASIoccur in deep gray nuclei, GP most common

BASAL GANGLIA T1 hyperintensity in GP, thought to be related to FASI&/or mineralization o Tl hyperintensity increases with age, but may resolve by adulthood • Hepatic Encephalopathy o GP & substantia nigra (SN) hyperintensity o History of liver disease • Hyperalimentation o Abnormal manganese metabolism in patients undergoing parenteral feeding o T1 hyperintensity in GP & SN o

Helpful Clues for Less Common Diagnoses • Hypoxic-Ischemic Encephalopathy, NOS o Includes anoxia, hypoxia, near drowning, & cerebral hypoperfusion injury o Tl & T2 hyperintense BG & cortical lesions o DWI restriction if acute • HIE, Term o Cerebral hypoperfusion injury o Several patterns of injury related to infant development, severity & duration of insult o Tl & T2 hyperintense BG & thalamus with profound insult o May involve posterior mesencephalon, hippocampi, & peri-Rolandic cortex • Hypotensive Cerebral Infarction o Insufficient cerebral blood flow o Border zone between major arterial terri tories typical o May be isolated to BG or thalami o T1 hyperintensity related to blood or pseudolaminar necrosis • CO Poisoning o Bilateral, symmetric GP T2 hyperintensity o May also involve putamen, thalamus, white matter (WM) o If hemorrhagic necrosis, Tl hyperintense • Kernicterus o Tl & T2 hyperintensity in GP in a neonate o Acute: Tl & (subtle) T2 hyperintensity in GP, hippocampi, SN o MR changes may be reversible with exchange transfusion in some cases • Wilson Disease o Children: T1 hyperintensity in GP o Children & adults: Symmetric T2 hyperintensity or mixed intensity in putamina, GP, caudate, & thalami o Characteristic "face of the giant panda" sign at midbrain level & T2 hyperintense WM tracts

11 HYPERINTENSE Helpful Clues for Rare Diagnoses

• Endocrine Disorders o All 5 may result in BG Ca++, particularly GP & putamen o May also see Ca++ of caudate dentate thalamus, SN, & subcortical WM ' o Symmetric involvement is typical o Variable Tl signal, often hyperintense, related to phase of calcification • Hypothyroidism 01'1 hyper- & T2 hypointensity in BG & SN o Etiologies include autoimmune disease & post-therapy (thyroidectomy, XRT) • Hyperparathyroidism o BG Ca++ typical, ± dural Ca++ (rare) o Etiologies include parathyroid adenoma & chronic renal failure • Hypoparathyroidism o Caudate nucleus> putamen & GP Ca++ o Dentate nuclei, centrum semiovale , cortex , & mesencephalic gray matter also involved o More diffuse Ca++ than other etiologies • Pseudohypoparathyroidism o BG Ca++ common o May see pulvinar & dentate nuclei Ca++ o Resistance to parathyroid hormone o Includes Albright hereditary osteodystrophy (AHO) • Short stature, obesity, brachydactyly, & ectopic ossifications • Pseudopseudohypoparathyroidism o Patients with AHO with normal responses to parathyroid hormone

BASAL GANGLIA May have hypoparathyroidism • Hypoglycemia o Neonatal hypoglycemic brain injury o Occipito-parietal edema or infarcts, ± BG • Hallervorden-Spatz Syndrome o Preferred terms: Pantothenate kinase-associated neurodegeneration (PKAN)or NBIA-l o Progressive neurodegenerative disorder with brain iron accumulation o "Eye of the tiger": Symmetric GP T2 hyperintensity surrounded by hypointensity o May see Tl hyperintensity in T2 hypointense areas (iron accumulation) • Fahr Disease o Bilateral symmetric BG Ca++ on CT o GP most common site for Ca++ o Putamen, caudate, thalami, cerebellum, cerebral WM may also be involved • Encephalitis (Miscellaneous) o Rabies encephalitis: 1'1 hyperintensity in bilateral BG, rare • Japanese Encephalitis o T2 hyperintense foci in WM , brainstem , BG, thalami bilaterally typical o If hemorrhagic, may see 1'1 hyperintensity • HIY, Congenital o BG Ca++ (30-85%) > frontal WM > cerebellum o Symmetric BG Ca++ & cerebral atrophy • GP & putamen> caudate o Tl hyperintensity related to Ca++ o

I Axial TlWI MR shows subtle hyperintensity in the CP BI related to physiologic calcification in this 76 year old patient. Calcification is a common normal variant in the aging brain

Axial Tl WI MR shows hyperintensity in the BC & thalamus in this NF I paUenL The CP & internal capsule are commonly involved. Note also large right BC FASI.

6 67

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(Lefl) Axial T1 WI MR shows hyperintensi/y in the BG, most prominent in the CP & blurring of the gray-white junctions related to acute edema in this hepatic encephalopathy patient. With treatment, reversal of the bright lesions is often seen in 3-6 months. (RighI) Axial T1WI MR shows hyperintense GP in a paUent receiving TPN. The hyperintensity is likely caused by manganese deposition &/o{ an

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reaction

to the

deposition.

HIE, Term (Lefl) Coronal T1 WI MR shows hyperinlensily in the BG, predominantly at the putamen 1::1] & caudate heads in this patient with hypoglycemia & hypoxia. Whether the damage is from the hypoglycemia or seizure-induced hypoxia is difficult to de/ermine. (RighI) Axial T1WI MR shows bright signal within the lentiform nucleus & lateral thalamus E!2 bilaterally, related to profound acute HIE in this neonate.

=

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CO Poisoning (Lefl) Axial T I WI MR shows hypointensity in the GP with

surrounding hyperintensity

-=

in this patient with a remote history of hypoxic-ischemic encephalopathy related to hypotension. Imaging mimics CO poisoning. (RighI) Axial T1WI MR shows heterogeneous signal in the GP bilaterally with areas of central hypoinlensily with a surrounding

I 6 68

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hyperintensity The heterogeneous signal is likely related to necrosis &/or blood products.

11 HYPERINTENSE

BASAL -GANGLIA III

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(Left) Axial T1 WI MR shows acute changes of kernicterus with T1 shortening in the GP & ventral thalami ~. A history of sustained or pronounced neonatal hyperbilirubinemia is typical. (Right) Axial T1WI MR shows mixed signal intensity in the putamen bilaterally ~ in a young adult with Wilson disease. Wilson disease is an inborn error of copper metabolism characterized by liver cirrhosis,

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Hallervorden-Spatz Syndrome (Left) Axial T1WI MR shows hyperintensity in the BG related to hyperdense calcifications in this patient with hypothyroidism. (Right) Coronal T1WI MR shows hypointense GP with surrounding hyperintensily ~. This corresponds to the "eye of the tiger" sign on T2 MR imaging in which T2 hyperintensity surrounded by pallidal T2 hypointensity (iron deposition).

(Left) Axial T1WI MR shows hyperintensity in the BG, predominantly involving the Gp, in this patient with Fahr disease. The corresponding CT showed dense calcification. (Right) Axial NECT shows symmetric BG calcification with scattered foci of symmetric subcortical calcification in the frOnial & parietal lobes. Note typical involvement of the lentiform nuclei greater than the caudate heads. T1 MR often shows corresponding hyperintensity in the Be.

I 6 69

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Common • Hypoxic-Ischemic Encephalopathy, o Hypotensive Cerebral Infarction o HIE, Term • Neurofibromatosis Type 1 • ADEM • CO Poisoning • Vasculitis o Systemic Lupus Erythematosus o Hemolytic Uremic Syndrome o Infectious Vasculitis

NOS

•

•

•

less Common • Drug Abuse • Gliomatosis Cerebri • Osmotic Demyelination Syndrome • Encephalitis (Miscellaneous) Rare but Important • Creutzfeldt-]akob Disease (CJD) • Acute Hypertensive Encephalopathy, • Metabolic, Inherited o Leigh Syndrome o Wilson Disease o MELAS o MERRF o Glutaric Aciduria Type 1 • Huntington Disease

•

PRES

•

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Basal ganglia (BG) are paired deep gray nuclei & include caudate nuclei, putamen, & globus pallidus (GP) • Lentiform nucleus: Putamen & GP • Corpus striatum: Caudate, putamen, & GP • Symmetric BG lesions suggest a toxic/metabolic process or hypoxia • DWI may help differentiate BG lesions

I 6 70

Border zone between major arterial territories typical o DWI restriction if acute HIE, Term o Involvement of BG & thalamus typically seen with profound insult o T1 & T2 hyperintensity in BG & thalamus o Ventrolateral thalamus typically involved o DWI restriction if acute Neurofibromatosis Type 1 o Focal areas of increased signal intensity (FASI)characteristic, BG typical o May also see FASIin brainstem ADEM o Multifocal white matter (WM) & BG lesions following infection/vaccination o Bilateral, asymmetric T2 hyperintensities CO Poisoning o Bilateral, symmetric GP T2 hyperintensity o May also involve putamen, thalamus, WM Vasculitis o Heterogeneous group of CNS disorders characterized by nonatheromatous inflammation & blood vessel wall necrosis o Angiography: Multifocal areas of smooth or mildly irregular stenosis alternating with dilatations o T2 hyperintensity in BG & WM o DWI restriction if acute Systemic Lupus Erythematosus o CNS involvement in up to 75% of cases, typically multifocal ischemia o True vasculitis of CNS is rare in SLE o Small multifocal WM lesions ± BG Hemolytic Uremic Syndrome o May cause vasculitis or hypertensive encephalopathy (PRES) o BG involvement typical in patients with neurological complications of HUS Infectious Vasculitis o Bacterial meningitis: Infarct due to vascular involvement seen in 25% o Tuberculous meningitis: Skull base vessels most commonly involved o Lenticulostriate artery involvement common o

DIFFERENTIAL DIAGNOSIS

Helpful Clues for Common Diagnoses • Hypoxic-Ischemic Encephalopathy, NOS o Includes anoxia, hypoxia, near drowning, & cerebral hypo perfusion injury o T1 & T2 hyperintense BG & cortical lesions o DWI restriction if acute • Hypotensive Cerebral Infarction o Infarct resulting from insufficient cerebral blood flow to meet metabolic demands o May be isolated to BG

•

•

Helpful Clues for less Common Diagnoses • Drug Abuse o Young/middle-aged patient with stroke o May cause stroke &/or vasculitis o T2 hyperintensities or hemorrhage in BG

12 HYPERINTENSE • Gliomatosis Cerebri o Diffusely infiltrating glial tumor involving 2 or more lobes, frequently bilateral o Typically hemispheric WM with BG or thalami (75%) o Often infiltrates beyond BG into WM • Osmotic Demyelination Syndrome o 50% in pons (CPM) & 50% extra-pontine sites (EPM): BG & cerebral WM o Symmetric hyperintensity in BG, WM • Encephalitis (Miscellaneous) o Many pathogens, most commonly viruses o Abnormal T2 hyperintensity of gray matter ± WM or deep gray nuclei o West Nile encephalitis: Symmetric BG, thalami, mesial temporal lobe, brainstem, & cerebellum T2 hyperintensities o Japanese encephalitis: High signal foci in WM, brainstem, BG, thalami bilaterally o Epstein-Barr virus: Symmetric BG, thalami, cortex, or brainstem T2 hyperintensities o Mycoplasma: May cause acute bilateral striatal necrosis Helpful Clues for Rare Diagnoses • Creutzfeldt-jakob Disease (C]D) o Progressive T2 hyperintensity of BG, thalamus, & cerebral cortex o Symmetric T2 hyperintense caudate nuclei, putamen> GP • Acute Hypertensive Encephalopathy, PRES o Typically seen in patients with severe hypertension

BASAL GANGLIA Patchy cortical/subcortical PCA territory lesions o BG involvement less common o No diffusion restriction on DWI typical Leigh Syndrome o Symmetric T2 hyperintense lesions with onset in infancy/early childhood o BG: Corpus striatum> GP o Bilateral lesions in putamen & peri-aqueductal gray are classic Wilson Disease o Symmetric T2 hyperintensity in putamen, GP, caudate, & thalami o Characteristic "face of the giant panda" sign at midbrain level & T2 hyperintense WM tracts MELAS o T2 hyperintensities in putamen, may be asymmetric or unilateral o Multifocal T2 hyperintensities in BG, deep WM in chronic phase MERRF o Propensity for BG, caudate nuclei o Watershed ischemia/infarcts common Glutaric Aciduria Type 1 o T2 hyperintensities in corpora striata, GP, ± WM disease o Characteristic opercular widening Huntington Disease o Hyperintense signal in caudate & putamen in juvenile HD o

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anoxic injury. Symmetry suggests a toxic/metabolic process or hypoxic-ischemic injury.

Axial FLAIR MR shows hyperintensity in the posterior putamen & lateral thalami in this neonate with profound HIE. OWl findings are most sensitive at 2 to 6 days after the HIE event.

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6 71

12 HYPERINTENSE

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BASAL GANGLIA

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Type 1

CO Poisoning

(Left) Axial T2WI MR shows foci of abnormal

signal

intensity (FASI) in the BC B. Lesions are usually bilateral but asymmetric. The CP is the most common location for FASI, though they maya/so be seen in the brainstem. (Right) Axial T2WI MR shows bilateral CP hyperintensities & diffuse hyperintensity throughout the white matter 81 but sparing of the subcortical U-fibers, typical of CO poisoning.

=

Infectious Vasculitis

Systemic Lupus Erythematosus (Left) Axial T2WI MR shows symmetric high signal intensity in the BC & thalami related to vasculitis, a rare manifestation of SLE. OWl is bright in the acute setting. SLE usually results in multifocal

ischemia

in the

white matter & Be. (Right) Axial T2WI MR shows confluent

hyperintensity

in

the BC bilaterally related to meningitis·induced vasculitis. OWl is bright in the acute selling.

Be

involvemenl

is

typical of lenticulostriate artery disease.

Osmotic

I 6 72

(Left) Axial T2WI MR multiple BC hyperintensities B caused by vasculitis in a young adult with a history of amphetamine abuse. OWl is bright in the acute setting. Drug abuse should be considered in a young adult with stroke. (Righi) Axial FLAIR MR shows extrapontine myelinolysis (EPM) as symmetric hyperintensities in the caudate head ~ & putamen 81 related to rapid correction of hyponatremia. EPM may occur without central pontine myelinolysis.

Demyelination

Syndrome

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T2 HYPERINTENSE BASAL GANGLIA

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Encephalitis

(Miscellaneous)

Creutzfeldt-Jakob

Disease (CJD) (Left) Axial FLAIR MR shows symmetric hyperintensities in the BC thalami, & insular cortex E1 in a West Nile encephalitis patient. Symmetric involvement of the BC, thalami, mesial temporal structures, brainstem, & cerebellum ;s typical. (Right) Axial T2WI MR shows symmetric hyperintensities in the caudate heads & putamen ~ in a patient with progressive dementia, cia. FLAIR & OWl are the most sensitive for diagnosing CjD.

=-

=

Acute Hypertensive

Encephalopathy,

PRES

leigh Syndrome (Left) Axial FLAIR MR shows symmetric increased signal intensity in the subcortical WM 8:1 & BC PJ:.:I related to PRES. OWl is typically negative in PRES.PRES usually involves posterior circulation territory. Be

involvement is uncommon. (Right) Axial T2WI MR

shows bilateral symmetric

=-

foci of abnormal signal in the caudate PJ:.:I & putamen typical of Leigh disease. Lack of associated mass effect indicates chronic disease.

MERRF

Glutaric

Aciduria Type 1 (Left) Axial T2WI MR shows mullifocal

hyperintensities

in

=..

the cortical gray maller putamen, & caudate head PJ:.:I bilaterally. Muscle biopsy disclosed findings consistent with myoclonic epilepsy with ragged red fibers (MERRF). (Right) Axial T2WI MR shows lentiform nuclei enlargement & hyperimensily 8:1. Note the wide sylvian fissures, typical of CA 1. OWl (not shown) revealed restricted diffusion within the lentiform nuclei.

I 6 73

ENLARGED PERIVASCULAR SPACES

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DIFFERENTIAL DIAGNOSIS Common • Normal Variant • Aging Brain, Normal

• Aging Brain, Normal o PVS are commonly seen as the brain loses volume as part of normal aging Helpful Clues for less Common Diagnoses • Cryptococcosis o Enlarged PVS in BG & superior brainstem o May see DWI hyperintense rim

less Common • Cryptococcosis Rare but Important • Mucopolysaccharidoses • Tumor-Associated Cysts, Nonneoplastic • CADASIL • Megalencephaly with Dilated Perivascular Spaces • Hypomelanosis of Ito

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Perivascular spaces (PVS) are pial-lined interstitial fluid-filled structures that accompany penetrating arteries • Most commonly seen as a normal variant Helpful Clues for Common Diagnoses • Normal Variant o Round/oval fluid-filled spaces that have CSF density/intensity, no enhancement o Rare mass effect (giant PVS) o Most commonly seen at anterior commissure, inferior basal ganglia (RG) o Common: Midbrain, deep white matter (WM), subinsular cortex, extreme capsule o Rare: Thalami, dentate nuclei, corpus callosum (CC), cingulate gyrus

Helpful Clues for Rare Diagnoses • Mucopolysaccharidoses o Enzyme deficiency & inability to break down glycosaminoglycan (GAG) o PVS dilated by accumulated GAG o CC & periatrial WM most common sites o Surrounding T2 hyperintensity common ± additional patchy WM signal • Tumor-Associated Cysts, Nonneoplastic o "Cysts" caused by enlarged/obstructed PVS reported with pituitary adenomas • CADASIL o Subcortical lacunar infarcts & leukoencephalopathy in young adults o Dilated PVS are frequent in CADASIL, involving temporal WM & BG o PVS dilation in CADASIL increases with age (may be related to aging or vascular wall alterations) • Megalencephaly with Dilated Perivascular Spaces o Enlarged WM PVS with surrounding T2 hyperintensity • Hypomelanosis of Ito o Large PVS with periventricular T2 hyperintensity

Normal Variant

I 6 74

=

Axial T2WI MR shows a small cluster of C5F-like slructures H1 along the anterior commissure at the inferior basal ganglia, the most common locaUon for

Axial TI C+ FSMR shows no enhancement of the PVS which is typical. Occasionally, the penetrating vessel may be seen centrally within the pvs. These

enlarged perivascular spaces.

occur as normal variants at al1ages.

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(Left) Axial T2WI MR shows multiple enlarged PVS in typical locations: Subcortical white mailer BG 8l & subinsular regions They are often bilateral & symmetric and are considered part of the normal aging process. Up to 2S% may have a small T2 hyperintense rim. (Right) Axial CECT shows multiple enlarged PVS in this patient with cryplococcosis.

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Note lack of enhancement,

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typical of this infection. Patients are often immunocompromised.

Mucopolysaccharidoses

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confluent

white

mailer disease. These PVS are filled with unmetabolized mucopolysaccharide. Note involvement of the corpus callosum a typical location for enlarged PVS in this disorder. (Right) Coronal T7 C+ FS MR shows a giant macroadenoma m with surrounding extratumoral cysts representing enlarged PVS that contain trapped pools of interstitial fluid.

=-

=

Megalencephaly with Dilated Perivascular Spaces

Hypomelanosis

of 110 (Left) Axial T2WI MR shows bilateral perivenlricular enlarged PVS 81 in a patient with megalencephaly. Findings suggest that PVS enlargement refleclS an underlying brain pathology causing neuroaxonaf damage. (Right) Axial FLAIR MR shows enlarged PVS with surrounding WM hyperintensity in this patient with incontinentia pigmenti (hypomelanosis of Ito). Patients with this rare syndrome have typical whorled skin lesions & may have hemimegalencephaly.

I 6 75

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Common • Meningitis • Neurosarcoid • Tuberculosis • Vasculitis Less Common • Glioblastoma Multiforme • Lymphoma, Intravascular (Angiocentric) • Cerebral Amyloid Disease Rare but Important • Metastases • Granulomatous Angiitis • Langerhans Cell Histiocytosis • Wegener Granulomatosis, Brain • Moyamoya (Mimic) • Meningioangiomatosis • Neurocutaneous Melanosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Perivascular spaces (PVS) are pial-lined, fluid-filled structures that accompany penetrating arteries • PVS follow CSF on all MR sequences • Rarely an enhancing vessel may be seen centrally within the PVS as a normal variant • Enhancement of PVS is typically related to infection, vasculitis, or tumor • Age of patient may help differentiate lesions

I 6 76

Helpful Clues for Common Diagnoses • Meningitis a Enhancing leptomeninges typical a Hydrocephalus very common a Inflammatory cells may extend along PVS a More common in children a May cause an infectious vasculitis; infarction due to vasculitis in 25% • Neurosarcoid a Multisystem inflammatory disease characterized by noncaseating granulomas a Meningeal enhancement typical (leptomeningeal & dural) a May invade brain via PVS & cause diffuse or focal mass-like lesions a Periventricular T2 hyperintense lesions common (50%)

May cause a small vessel vasculitis (involves penetrating arteries) • Tuberculosis a Meningitis + parenchymal lesions common appearance a Inflammatory cells may extend along PVS a May cause an infectious vasculitis • Skull base vessels most commonly involved (supracJinoid ICA & Ml) • Vasculitis a Heterogeneous group of CNS disorders with inflammation & blood vessel necrosis a Primary or secondary to systemic disease a Alternating stenosis, dilatation primarily involving 2nd, 3rd order branches a Angiography best for diagnosis a Multifocal ischemia in subcortical white matter (WM) & basal ganglia (BG) a May cause PVS enhancement a

Helpful Clues for Less Common Diagnoses • Glioblastoma Multiforme a Peripherally enhancing, centrally necrotic WM mass typical a Often involves corpus callosum a May metastasize along PVS • Lymphoma, Intravascular (Angiocentric) a Rare malignancy characterized by intravascular proliferation of lymphoid cells with a predilection for CNS & skin a Multifocal T2 hyperintensity in deep WM, cortex, or BG + enhancement typical a May see cortical infarct-like lesions a May cause a vasculitis • Cerebral Amyloid Disease a Lobar hemorrhages of different ages & multifocal "black dots" typical a Amyloid deposits may occur along PVS a May cause a vasculitis a Occurs in elderly adults Helpful Clues for Rare Diagnoses • Metastases a Multifocal parenchymal enhancement at gray-white interfaces typical a May rarely spread along PVS or involve meninges a Primary tumor often known • Granulomatous Angiitis a Primary angiitis isolated to the CNS (idiopathic) a Manifests as multiple intracranial stenoses a May cause PVS enhancement in BG or WM

PERIVASCULAR

SPACE ENHANCING

LESIONS

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• Langerhans Cell Histiocytosis o Thick enhancing pituitary stalk is most common CNS manifestation o Lack of pituitary "bright spot" o May extend along PVS o Rarely causes enhancing choroid plexus, BG, &/or leptomeningeal nodules • Wegener Granulomatosis, Brain o Chronic systemic arteritis involving lungs, kidneys, & sinuses o CNS involved in 15-30% due to direct invasion from nose/sinuses o May cause intracerebral & meningeal granulomas or vasculitis o May cause meningeal & PVS enhancement • Moyamoya (Mimic) o Moyamoya is an angiographic pattern o Idiopathic progressive arteriopathy of childhood o Slowly progressive occlusion of the supraclinoid ICAs o T2 MR shows multiple dark flow voids in BG related to lenticulostriate collaterals o Contrast MIl.shows enhancement of these collaterals mimicking PVS enhancement o Pattern has been reported with neu rofibromatosis, atherosclerosis, radiation therapy • Meningioangiomatosis o Cortical mass with enhancement & Ca++ o Proliferation of blood vessels & meningothelial cells around vessels in meninges, cortex, & underlying WM o Often extends into cortex via PVS

NF2 in about 1/2 of patients Children, young adults usually present with seizures or headaches • Neurocutaneous Melanosis o Rare phakomatosis: Giant or multiple cutaneous melanocytic nevi & melanocytic lesions of the leptomeninges & parenchyma o Melanocytes often confined to PVS in parenchymal melanosis o Amygdala, cerebellum, basis pontis, & thalami common parenchymal sites o o

Alternative Differential Approaches

• PVS enhancing lesions in a child o Meningitis, TB, Langerhans cell histiocytosis, moyamoya (mimic), meningioangiomatosis, neurocutaneous melanosis • PVS enhancing lesions in an adult o Neurosarcoid, TB, vasculitis, GBM, intravascular lymphoma, metastases, cerebral amyloid disease, granulomatous angiitis, Wegener granulomatosis • PVS enhancing lesions in an elderly adult o GBM, intravascular lymphoma, metastases, cerebral amyloid disease

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Neurosarcoid

I Coronal Tl c+ MR shows striking enhancement in the PVS 8lI along the penetrating arteries in the basal ganglia in this patient with bacterial meningitis.

Diagnosis is made by lumbar puncture.

Coronal T1 c+ MR shows nodular parenchymal enhancement 8lI in the frontal lobe of this sarcoid patient Parenchymal involvement is typically caused by PVS invasion of the granulomatous disease.

6 77

PERIVASCULAR

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foci

m

along the penetrating perivascular spaces in this TB meningitis patient. TB may cause a true vasculitis with muflifocallacunar & cortical infarcts as sequelae. (Right) Axial T' C+ MR shows striking enhancement in the brain parenchyma & perivascular spaces of the basal ganglia in this HIV patient. I-{IV vasculitis is

=

increasing

in incidence,

particularly

in children.

Glioblastoma

Multiforme

(Left) Axial TI C+ F5 MR shows multifocal glioblastoma multiforme with involvement of the PV5 as patchy contrast enhancement s::I in the basal ganglia. (Right) Coronal TI C+ MR shows linear enhancement along the

perivascular spaces ED representing lymphoma. enhancement of T2 white abnormality.

intravascular This occurs in areas mailer signal The linear

enhancement

along PVS can

help suggest the diagnosis in a dementia patient.

Cerebral (Left) Axial TI C+ MR shows nodular enhancement representing intravascular lymphoma involving the perivascular spaces. Enhancement patterns are variable in intravascular lymphoma & may be linear, punctate, patchy, nodular, ring-like, gyriform, or homogeneous. (Right) Axial TI C+ MR shows nodular

=

enhancement

I 6 78

in the basal

ganglia ~ related to amyloid in the perivascular spaces. Amyloid deposits are typically interstitial, vascular, or perivascular.

Amyloid

Disease

PERIVASCULAR

SPACE ENHANCING

lESIONS III

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(Left) Coronal T1 C+ MR shows linear enhancement along the perivascular spaces of the frontal lobes. Imaging mimics sarcoid & intravascular lymphoma. Biopsy disclosed granulomatous angiitis. (Right) Axial T7 C+ MR

=.2

shows punctate

&

linear

enhancement in the tempora/lobe & pons =.2 representing involvement of

the perivascular spaces. Biopsy disclosed Langerhans cell histiocytosis in this young patient.

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shows irregular enhancement in the frontal lobes of this patient with Wegener granulomatosis of the paranasal sinuses. Invasion of the meninges & brain from the sinuses occurs in up to 30% of these patients. (Right) Axial T7 C+ MR shows enhancing lenticulostriate collateral vessels in the basal ganglia related to the patienes dista//CA stenosis bilaterally. These colfalerals mimic

=

perivascular space enhancement.

(Left) Coronal T1 C+ MR shows linear enhancement =.2 related to a calcified pial-based mass seen on CT. Meningioangiomatosis infiltrating

the brain

parenchyma via the PVS was identified at surgery. (Right) Axial T7 C+ MR shows a strongly enhancing superficial mass that fills the adjacent sulci & extends into the underlying brain. Surgery disclosed exlensive melanosis that had invaded the brain via the perivascular spaces.

I 6 79

Cll

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LESIONS

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Common • Enlarged Perivascular Spaces • Lacunar Infarction o Atherosclerotic o Other Vasculopathy; Vasculitis • Mineralization • Manganese Toxicity o Liver Disease; Hyperalimentation • Hypoxic-Ischemic Encephalopathy • Neoplasm o CNS Lymphoma; Astrocytoma • Trauma • Neurofibromatosis Type 1 • Toxin Exposure/Drug Abuse Less Common • Infection o Cryptococcosis; Toxoplasmosis; Viral Encephalitides • Osmotic Demyelination Syndrome • ADEM • Posterior Reversible Encephalopathy Syndrome (PRES) • Venous Ischemia/Infarction Rare but Important • Neurosarcoidosis • Creutzfeldt-]akob Disease (C]D) • Mitochondrial Encephalopathies o Leigh Syndrome; MELAS • Huntington Disease • Metabolic Disorders o Wilson Disease o Pantothenate Kinase Associated Neurodegeneration (PKAN) o Organic Acidopathies

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Basal ganglia (BG) "lesions" may be normal variants (e.g., perivascular spaces), normal changes over time (e.g., Ca++, iron deposition in the aging brain), or true pathology

I 6 80

Helpful Clues for Common Diagnoses • Enlarged Perivascular Spaces o Very common, especially in older patients o Follow CSF on all sequences o If extensive in BG, so-called "etat crible"

• Lacunar Infarction o Reduced diffusion if acute o May mimic enlarged perivascular space if chronic, but typically t SI on FLAIR o Usually due to small vessel disease in patients with vascular risk factors o May be due to vasculitis (infectious or non-infectious) or non-atherosclerotic vasculopathy (e.g., CADASIL) • Mineralization o In normal aging, usually affects globus pallidus (GP) o Involvement of caudate &/or putamen suggests underlying metabolic condition o Check for radiation, chemotherapy history • Manganese Toxicity o Attributed to t manganese (Mn) levels o Also seen with total parenteral nutrition ~ high serum Mn levels o Bilateral symmetric GP t Tl SI • Common in patients with chronic liver disease • Hypoxic-Ischemic Encephalopathy o Often also involves cerebral cortex, hippocampi, thalami o Reduced diffusion in acute phase • Neoplasm o CNS lymphoma commonly involves bilateral BG • Typically intermediate SI on T2WI, enhance post-gad, mild. diffusion o Astrocytoma may diffusely infiltrate BG • Bithalamic involvement common • ± Extension into midbrain • Trauma o Axonal stretch/shear vs. tearing of lenticulostriate vessels o Variably hemorrhagic o GRE/SWI useful • Neurofibromatosis Type 1 o Areas of T2 t SI are common in the GP, brainstem, & cerebellar white matter (WM) o Represent areas of myelin vacuolization & myelin dysplasia • Toxin Exposure/Drug Abuse o CO poisoning characteristically causes symmetrical T2 bright lesions of the GP o Drugs of abuse, notably heroin, may cause injury similar to CO poisoning o Cyanide may cause selective injury to GP, subthalamic nuclei, cerebellum

BILATERALBASALGANGLIA LESIONS Helpful Clues for Less Common Diagnoses • Infection o Cryptococcal meningitis: Gelatinous pseudocysts cause multiple t T2 foci in BG • Usually nonenhancing, no • diffusion, seen in HIV+ patients o Toxoplasmosis: Ring-enhancing lesions o Viral encephalitis: Many types may affect BG, often symmetrically • Osmotic Demyelination Syndrome o Caudate nuclei, putamina are common locations for extrapontine myelinolysis o Typically symmetrical T2 hyperintensity • ADEM o Patchy, asymmetrical BG t T2 lesions o Also subcortical WM, thalami, spinal cord, optic nerves • Posterior Reversible Encephalopathy Syndrome (PRES) o BG involvement usually accompanied by subcortical WM t T2 lesions • Venous Ischemia/Infarction o BG involvement usually occurs with severe bithalamic involvement Helpful Clues for Rare Diagnoses • Neurosarcoidosis o Enhancing nodules with edema • Creutzfeldt-]akob Disease (C]D) o T2 hyperintensity may variably affect bilateral BG, thalami, & cerebral cortex o Cortical involvement usually asymmetric, while BG & thalami more symmetric o Reduced diffusion; no enhancement

• Mitochondrial Encephalopathies o Often symmetrical except MELAS o Reduced diffusion in acute phase of injury • Huntington Disease o T2 hyperintensity & severe atrophy of bilateral caudate, putamina • Metabolic Disorders o Large number of inborn errors of metabolism can affect bilateral BG o Also acquired conditions such as kernicterus, hypoglycemia o Wilson disease: Autosomal recessive (AR); • biliary excretion of copper; t T2 Sl in BG o PKAN:AR disorder of coenzyme A metabolism; "eye of the tiger" sign in GP; symmetrical t T2 surrounded by • T2

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Alternative Differential Approaches • Bilateral caudate and putamina I lesions o Symmetrical: HIE; extra-pontine myelinolysis; Wilson disease o Variably symmetrical: CJD; toxic, metabolic, or mitochondrial processes o Asymmetrical: Enlarged perivascular spaces; lacunar infarcts; vasculitis; neoplastic infiltration; ADEM o Reduced diffusion: HIE; vasculitis or vasculopathy; C]D; encephalitis; metabolic or mitochondrial disorder • Bilateral globus pallidus lesions o Symmetrical: HIE; CO poisoning; manganese toxicity; PKAN o Asymmetrical: Mineralization (variable); NFl (variable)

Lacunar Infarction

I Axial T2WI MR shows multiple small punclale foci of t 51 in bilateral caudate nuclei & putamina that {ollow CSF on all sequences. Thalami & perivemricular WM show evidence of chronic ischemic change.

=

Axial OWl MR shows multiple small asymmetrical foci of • diffusion in the Be & in the hemispheric WM EZl This patient had meningitis & infectious vasculitis affecUng multiple small vessels.

6 81

BILATERAL BASAL GANGLIA

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LESIONS

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=

with

pseudohypoparathyroidism. Ca++ associated with normal aging affec!s the Cp, usually symmetrically. (Right) Axial T1WI MR shows symmelrical t 51 in the CP in a patient with end·scage liver disease from hepatic cirrhosis. After liver transplantation, the signal abnormality regressed over time.

(Left) Axial OWl MR shows symmetrical diffusion in the caudate nuclei 81 & putamina in a patient who suffered cardiac arrest & was comatose. There is also ~ diffusion in the cortical ribbon, most evident in the occipital lobes ~ (Right) Axial CECT shows contrast-enhancing masses with associated vasogenic edema involving the caudate nuclei i:llI & the ependymal surfaces of bilateral fron!al horns. An enhancing mass E1 is also seen in the atrium.

*

=

Trauma (Left) Axial T2 CRE MR shows severe traumatic injury, with scalp hemalomas, 5AH, fVH, bifrontal hemorrhagic contusions, & hemorrhagic shear injury of the BG i:llI & !halamus 81. Edema is also present in the putamina & frontal lobes. Swelling of the right temporal cortical ribbon ~ was due to vascular injury & MCA infarct (Right) Axial T2WI MR shows t 51 in the CP & lef! > right thalami 81 in a child with Nfl, representing myeNn vacuolization.

=

I 6 82

Neurofibromatosis

Type 1

BILATERAL BASAL GANGLIA

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LESIONS

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OJ (LeFt) Axial FLAIR MR shows fairly symmetric t 51 in the GP I:] & hemispheric WM in a severely altered patient days after being found in a mobile home with a faulty propane heater. Imaging typical of CO poisoning. (Right) Axial PO F5f MR shows "fluffy" irregular t 51 without mass effect involving bilateral caudate nuclei & putamina. diffusion

There was no

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(Left) Axial T2WI MR shows diffuse symmetrical t 51 in bilateral caudate nuclei & putamina in a patient who had rapid correction of hyponatremia. Diffuse t 51 of the inner cortex/subcortical WM is also seen. (Righi) Axial OWl MR shows asymmetrical J. diffusion in the caudate

nuclei

&

Anterior>

putamina ED. posterior

putamina! abnormality is typical of C/O. Note also asymmetrical

~ diffusion

in

the frontal & temporal lobe cortical ribbon 1:].

(LeFt) Axial FLAIR MR shows patchy t 51 in bilateral caudate & putamina in a young child with pyruvate dehydrogenase complex deficiency & an acute clinical

decompensation. These lesions showed J. diffusion & no post-gadolinium enhancement. (Right) Coronal FLAIR MR shows fairly symmetric t 51 in the bilateral caudate nuclei & putamina in this patient with Wilson disease, a rare

autosomal recessive disorder characterized by impaired biliary excretion of copper.

I 6 83

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DIFFERENTIAL DIAGNOSIS Common • Hypertensive Intracranial Hemorrhage • Hypoxic-Ischemic Encephalopathy o HIE, Term o Hypotensive Cerebral Infarction less Common • Methanol Toxicity • Osmotic Demyelination • Leigh Syndrome

Syndrome

Rare but Important • Creutzfeldt-]akob Disease (C]D) • Huntington Disease • Parkinson Disease • Multiple System Atrophy

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Hypertensive Intracranial Hemorrhage o Related to systemic hypertension o Putamen most common (60-65%) o Look for underlying lesion if no hypertension! • Hypoxic-Ischemic Encephalopathy o Includes anoxia, hypoxia, near drowning, & cerebral hypoperfusion injury o T1 & T2 hyperintense basal ganglia (BG) & cortical lesions; may affect only putamen o HIE, Term • Acquired, usually cerebral hypoperfusion

o

• Profound acute HIE - deep gray matter, posterior mesencephalon, hippocampi, & peri-Rolandic cortex injury Hypotensive Cerebral Infarction • May be isolated to deep nuclei, BG • Bilateral, symmetric T2 hyperintensity • DWI bright in acute setting!

Helpful Clues for less Common Diagnoses • Methanol Toxicity o Putaminal necrosis, ± hemorrhage o Symmetric T2 hyperintense lesions o Often subcortical WM lesions • Osmotic Demyelination Syndrome o Extrapontine myelinolysis results in T2 hyperintensity in putamen & caudate • Leigh Syndrome o Symmetric T2 hyperintense lesions with onset in infancy/early childhood o Lesions primarily in brains tern, BG & WM; putamen> GP Helpful Clues for Rare Diagnoses • Creutzfeldt-]akob Disease (CJD) o Progressive T2 hyperintensity of BG, thalamus, & cerebral cortex o Putamen & caudate> GP • Huntington Disease o Caudate atrophy, t T2 caudate/putamen • Parkinson Disease o Hypointensity of putamen (iron) o ± T2 hyperintense foci in putamen & GP • Multiple System Atrophy o Posterior putaminal atrophy ± T2 hyperintensity or hypointensity (iron)

I 6 84

Axial NECT shows a large hemorrhage in the putamen with extension laterally into adjacent while matter. If there is no hyperlension hislory, an underlying lesion should be considered.

Axial NEeT shows hypodensily in the putamen ~ bilaterally related to infarcts in this 2 month old who had a near drowning even/. This type of I liE often a(feelSthe deep gray nuclei.

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(Left) Axial T1 WI MR shows hyperintensity within the putamen !:ll & lateral thalami related to profound asphyxia in this newborn. Several patterns of HIE may occur related to

=

infant development,

severity

& duration of insult. Involvement of BG & thalamus is typically seen with profound insult. (RighI) Axial NECT shows mixed density lesions in the BG. Note gross & petechial hemorrhage in the putamen typical of acute methanol toxicity.

=-

Osmotic Demyelination

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Syndrome (Left) Axial fLAIR MR shows extrapontine myelinolysis ([PM) with symmetric hyperintensity in the putamen & caudate heads bilaterally. EPM may occur with or without

=

pontine

involvement.

(Right)

Axial T2WI MR shows symmetric hyperintensity in the putamen ~ with associated edema related to acute Leigh syndrome. Hyperintensity was also noted in the periaqueductal gray, which is sensitive for diagnosis of Leigh syndrome.

Creutzfeldt-Jakob

Disease (CJD)

Huntington Disease (Left) Axial fLAIR MR shows symmetric hyperintensity within the putamen SI & pulvinar of the thalamus !:ll in this patiellt with C/O. Involvement of the caudate heads is also typical. FLAIR & OWl are the most sensitive MR sequences for this diagnosis. (Right) Axial PO FSE MR shows volume loss of the caudate heads SI. Note symmetric hyperintensity in the caudate heads & putamen typical of juvenile HUnlingtof1

=-

disease.

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PALLIDUS LESION(S)

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DIFFERENTIAL DIAGNOSIS Common • Hypoxic-Ischemic Encephalopathy, • HIE, Neonate • CO Poisoning • Neurofibromatosis Type 1

NOS

Less Common • Drug Abuse • Hyperalimentation • Hepatic Encephalopathy • Leigh Syndrome • Cyanide Poisoning • Kernicterus • Hypothyroidism • Fahr Disease Rare but Important • eurodegeneration with Brain Iron Accumulation (NBIA) • Hallervorden-Spatz Syndrome • Maple Syrup Urine Disease • Methylmalonic Acidemia • Wilson Disease

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Globus pallidus (GP) are paired deep nuclei within the basal ganglia (BG) with lateral & medial segments • Lentiform nucleus = putamen & GP • Corpus striatum = caudate, putamen, & GP • Majority of GP lesions are symmetric indicating a toxic/metabolic process or hypoxia • Lesions may be differentiated based on patient age or Tl/T2 signal abnormality

I 6 86

Helpful Clues for Common Diagnoses • Hypoxic-Ischemic Encephalopathy, NOS o Includes anoxia, hypoxia, near drowning, & cerebral hypoperfusion injury o Occurs in adult or child, pattern depends on severity of insult o Tl & T2 hyperintense BG & cortical lesions; may affect only GP • HIE, Neonate o Acquired condition related to cerebral hypoperfusion o Several patterns of injury related to infant development, severity & duration of insult

Involvement of BG & thalamus typically seen with profound insult o Tl & T2 hyperintensity in BG & thalamus o Ventrolateral thalamus typically involved • CO Poisoning o Bilateral, symmetric GP T2 hyperintensity o May also involve putamen, thalamus, white matter (WM) o If hemorrhagic necrosis, Tl hyperintense o Chronic: T2 hyperintensity in centrum semiovale, internal/external capsules, & corpus callosum often seen • Neurofibromatosis Type 1 o Focal areas of increased signal intensity (FASI)characteristic o FASI:T2 hyperintensities within deep nuclei, most commonly affecting GP o May be present within brainstem o FASIare transient & rarely enhance o

Helpful Clues for Less Common Diagnoses • Drug Abuse o Methylenedioxymethamphetamine (a.k.a. MDMA, "Ecstasy") causes bilateral GP ischemia from prolonged vasospasm o Heroin: GP ischemia &/or toxic leukoencephalopathy, hypoxic brain injury o MDMA & heroin: T2 hyperintense GP o Heroin inhalation: Symmetric WM T2 hyperintensity • Hyperalimentation o Abnormal manganese metabolism in patients undergoing parenteral feeding o Tl hyperintensity in GP & substantia nigra (S ), related to manganese • Hepatic Encephalopathy o Tl hyperintensity in GP & SN o History of liver disease • Leigh Syndrome o Symmetric T2 hyperintense lesions with onset in infancy/early childhood o Lesions primarily in brainstem, BG & WM; putamen> GP • Cyanide Poisoning o Bilateral T2 hyperintense GP o May involve cerebellar cortex o Causes hemorrhagic necrosis • Kernicterus o Tl & T2 hyperintensity in GP in a neonate o Acute: Tl & (subtle) T2 hyperintensity in GP, hippocampi, SN

GLOBUS

PALLIDUS LESION(S)

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Chronic: T2 hyperintensity in GP & dentate nucleus o MRI changes may be reversible with exchange transfusion in some cases • Hypothyroidism o T1 hyperintensity & T2 hypointensity in BG & SN related to calcification (Ca++) o Diffuse WM T2 hyperintensity in Hashimoto thyroiditis • Fahr Disease o Bilateral symmetric BG Ca++ on CT o GP most common site o Putamen, caudate, thalami, cerebellum, cerebral WM may also be involved o

Helpful Clues for Rare Diagnoses

• Neurodegeneration with Brain Iron Accumulation (NBIA) o Includes Hallervorden-Spatz, aceruloplasminemia, neuroferritinopathy o Progressive neurodegenerative disorder with extrapyramidal motor impairment & brain iron accumulation o T2 hypointensity in GP & SN • Hallervorden-Spatz Syndrome o Preferred terms: Pantothenate kinase-associated neurodegeneration (PKAN)or NBIA-l o "Eye of the tiger": Bilateral, symmetric GP t T2 surrounded by hypointensity o Symmetric T2 hyperintense SN • Maple Syrup Urine Disease o T2 hyperintensity in cerebellar WM, brainstem, GP

May affect thalamus, cerebral peduncles, corticospinal tracts • Methylmalonic Acidemia o Bilateral GP T2 hyperintensity, ± periventricular WM • Wilson Disease o Children: T1 hyperintensity in GP o Children & adults: Symmetric T2 hyperintensity or mixed intensity in putamina, GP, caudate, & thalami o Characteristic "face of the giant panda" sign at midbrain level & T2 hyperintense WM tracts o

Alternative

Differential

Approaches

• Tl hyperintense GP lesions: HIE, CO poisoning, hyperalimentation, hepatic encephalopathy, kernicterus (acute), hypothyroidism, Wilson disease (child) • T2 hyperintense GP lesions: HIE, CO poisoning, NFl, drug abuse, Leigh syndrome, cyanide poisoning, kernicterus (chronic), PKA , MSUD, MMA, Wilson disease • GP lesions in a child: HIE, NFl, Leigh syndrome, kernicterus, NBIA, PKAN,MSUD, MMA, Wilson disease • GP lesions in an adult: HIE, CO poisoning, drug abuse, hyperalimentation, hepatic encephalopathy, cyanide poisoning, hypothyroidism

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I Axial FLAIR MR shows hyperintensity in lhe GP bilaterally E1 related to an acute hypoxic·ischemic event. Imaging mimics CO fXJisoning or other drug

Axial T1WI MR shows brighl signal wilhin lhe Gp, putamen, & latera/thalamus. Imaging pattern is typical for profound acute HIE, seen in an acute event such as

abuse. DWI is positive in the acute setting.

uterine rupture or cord prolapse.

6 B7

GLOBUS

PAlliDUS

CO Poisoning (Left) Axial FlAIR MR shows heterogeneous hyperintensity within the globus pallidus 81 bilaterally related 10 CO poisoning. The heterogeneity is likely related to necrosis &/o(

c: IV •...

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blood

produc15. (Right) Axial FlAIR MR shows extensive Focal

areas of increased signal intensity (FASI) 81 in the GP in this NFl patient most common

GP is

location

for

FASI. Enhancement of these lesions is worrisome but does nol always signal neoplastic change.

(Left) Axial PO FSEMR shows hyperintense GP 81 related to heroin abuse in this young adult, likely related to ischemia. MOMA would mimic this appearance. (Right) Axial T7 WI MR shows bilateral, symmetric hyperintensity in the BC, predominanlly in the GP ~. This hyperintensity resolved after therapy. The patient's movement disorder also resolved, showing that both clinical & imaging findings of hepalOcerebral degeneration can be reversible.

(Left) Axial T2WI MR shows bilateral,

symmetric

hyperintensilies in the putamina & CP The (;ndings are suggestive of mitochondrial encephalopathy. (Right) Axial T2WI MR shows symmetric hyperintensities in the CP bilaterally in this adult patient with a history of cyanide poisoning history.

=.

=

Differential

considerations

in

an adult would include CO poisoning, drug abuse, & hypoxia.

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Neurofibromatosis

Type 1

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GLOBUS PALLIDUS LESION(S)

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Kernicterus (Left) Axial T1WI MR shows hyperintensity in the GP in this child with acute kernicterus. There are many causes for elevation of bilirubin to toxic levels; the most common worldwide is erythroblastosis fetalis. (Right) Axial T2WI MR shows hyperintensity in the GP bilaterally in this child with treated hyperbilirubinemia. MR obtained at 6 month follow-up shows typical GP hyperintensity of chronic

=

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kernicterus.

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bilateral hyperinl€nsities in the medial GP ~ in this patient with hypothyroidism related to prior thyroidectomy. (Right) Axial T2WI MR shows symmetric hypointensity within the GP 81. The "eye of the tiger" appearance is absent, characteristic of NBIA Although physiologic brain iron accumulation in the GP & SN may be identified in young adults, the degree of T2 hypointensily in this case is abnormal.

(Left) Axial T2WI MR shows classic "eye of the tiger" appearance of PKAN.- Small, symmetric hyperintense foci in the anteromedial GP on a background of hypointensity r=.:l. This appearance has a nearly 7.- I correlation with the PKAN2

=

mutation,

hence the new

designation of PKAN. (Right) Axial T2WI MR shows symmetric hyperintensity in the GP bilaterally in this

=

metlly/malonic

acidemia

patient. Associated WM

hyperinlensily is

variable.

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DIFFERENTIAL DIAGNOSIS Common • Lacunar Infarction • Hypertensive Intracranial Hemorrhage • Neurofibromatosis Type 1 Less Common • Diffuse Astrocytoma, Low Grade • Glioblastoma Multiforme • Anaplastic Astrocytoma • ADEM Rare but Important • Multiple Sclerosis • Thrombosis, Deep Cerebral Venous • Germinoma

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Lacunar Infarction o Small, < 1.5 em T2 hyperintensity in thalamus or basal ganglia (BG) o DWI restriction if acute o Related to ischemia of penetrating vessels • Hypertensive Intracranial Hemorrhage o BG > thalamus> pons/cerebellum> hemisphere bleed in a hypertensive patient o 15-25% in thalamus o May enhance subacutely o Intraventricular hemorrhage common • Neurofibromatosis Type 1 o Focal areas of signal intensity (FAS!)in deep gray matter characteristic (60-85%)

o o o

Globus pallidus, white matter (WM), thalami, hippocampi, brainstem Bilateral> > unilateral No enhancement!

Helpful Clues for Less Common Diagnoses • Diffuse Astrocytoma, Low Grade o Nonenhancing T2 hyperintense mass o May be bilateral • Glioblastoma Multiforme o Peripherally enhancing WM mass typical o May involve thalamus or BG • Anaplastic Astrocytoma o T2 hyperintense mass ± enhancement • ADEM o Muitifocal WM &/or BG lesions following infection/vaccination o Thalamic involvement common o Typically bilateral, but asymmetric lesions Helpful Clues for Rare Diagnoses • Multiple Sclerosis o Periventricular WM, corpus callosum T2 hyperintense lesions most common o Rarely involves thalamus • Thrombosis, Deep Cerebral Venous o Typically bilateral, related to internal cerebral vein (ICV) thrombosis o T2 hyperintensity in thalamus o Hyperdense lCV on CT • Germinoma o Enhancing mass in pineal or suprasellar region; 5-10% involve BG or thalamus

Lacunar Infarction

I 6 90

Axial FlAIR MR shows a focal hyperintensity within the thalamus

=

related to an acute lacunar infarct. Note abnormal perivenlricular hyperintensity related to

chronic small vessel ischemia 81.

Axial NEeT shows a hypertensive hemorrhage p:J with associated intraventricular hemorrhage, a common complication. The thalamus is the second most common location for hypertensive hemorrhages.

UNILATERAL THALAMIC

en

LESION

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Hypertensive

Intracranial

Hemorrhage

Neurofibromatosis

Dl

Type 1 (Left) Axial T2' eRE MR shows muttiFocal areas of "blooming" related to hemosiderin in this chronic hypertension patient. Note large area in left thalamus ~ related to a prior hypertensive hemorrhage. (Right) Axial FLAIR MR shows multiple foci of abnormally increased signal in the globus pallidus & thalamus typical of NFl. They are related focal areas of signal intensity (FAS/), which are most common in the deep gray nuclei.

=

Diffuse Astrocytoma,

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Low Grade (Left) Axial FLAIR MR shows a discrete basal ganglia & thalamic hyperintense mass with a distinct lack of surrounding edema. 20% of low grade astrocytomas involve deep gray matter~ including the thalamus & basal ganglia. (Right) Axial T1 C+ MR shows an enhancing right thalamic mass, anaplastic astrocytoma Although these usually occur in white matter, involvement of the deep gray nuclei is not uncommon.

=.

Thrombosis,

Deep Cerebral

Venous (Left) Axial T2WI MR shows large confluent regions of hyperintense signal in the white matter BI & thalami ADEM predominantly involves white matter.

=.

Bilatera/

is more common

than unifateral disease. (Right) Axial T2WI MR shows bilateral thalamic hyperintensity related to internal vein thrombosis. Bilateral disease is much more common than unilateral. Hemorrhage often accompanies venous thrombosis typically parenchymal.

=

I 6 91

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BITHAlAMIC LESIONS

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DIFFERENTIAL DIAGNOSIS Common • Arterial Ischemia • Venous Ischemia/Deep Venous Thrombosis • ADEM • Diffuse Astrocytoma/Gliomatosis Cerebri less Common • Hypoxic-Ischemic Encephalopathy, NOS o HIE, Term Neonate o Profound Hypoperfusion Injury, Adult • Acute Hypertensive Encephalopathy, PRES • Lymphoma, Primary C S • Multiple Sclerosis • Vasculitis • Wernicke Encephalopathy • Osmotic Demyelination Syndrome • Encephalitis/Encephalopathy o Viral (Multiple Agents) o Acute Necrotizing Encephalopathy (ANE) of Childhood Rare but Important • Creutzfeldt-]akob Disease (CJD) • Paraneoplastic Syndromes • Inborn Errors of Metabolism o Krabbe Disease o Wilson Disease o GMI, GM with Gangliosidoses • Mitochondrial Disorders • Solvent Inhalation, Toxic Ingestion • Fahr Disease • Kernicterus

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Reduced diffusion in bithalamic process: Artery of Percheron infarct; bilateral PCA infarcts; encephalitis; HIE; vasculitis; metabolic disorder; mitochondrial disorder • Bithalamic lesions with hemorrhage: Deep venous thrombosis; vasculitis; encephalitis • Symmetrical bithalamic lesions: Wernicke encephalopathy; osmotic myelinolysis; HIE; CJD; inborn errors of metabolism

I 6 92

Helpful Clues for Common Diagnoses • Arterial Ischemia o Often associated with vertebrobasilar disease, "top of the basilar" syndrome

Acute onset of symptoms, reduced diffusion o Artery of Percheron infarct: Occlusion of a common vascular trunk that arises from one PI segment, supplies bilateral thalami o Infarction of midbrain often also present • Venous Ischemia/Deep Venous Thrombosis o Usually thrombosis of vein of Galen, straight sinus, bilateral internal cerebral veins o Edema, swelling with venous ischemia o Reduced diffusion, parenchymal hemorrhage with venous infarction o CTV or MRV useful to establish specific diagnosis • ADEM o Often affects thalami bilaterally o May cause swelling, T2 hyperintensity, variable enhancement o Usually associated with white matter (WM) lesions elsewhere in brain, with T2 high signal & variable gad enhancement • Diffuse Astrocytoma/Gliomatosis Cerebri o Bithalamic infiltration by neoplastic cells usually occurs with diffuse astrocytoma or gliomatosis cerebri o

Helpful Clues for less Common Diagnoses • Hypoxic-Ischemic Encephalopathy, NOS o Commonly affects bilateral thalami when profound • Diffuse thalamic injury in preterm neonates • Lateral thalamic injury in term neonates o Thalamic injury in adults usually accompanied by global severe injury to cortex, hippocampi, & basal ganglia • Acute Hypertensive Encephalopathy, PRES o Thalamic involvement typically occurs in patients who also have classic symmetrical parietooccipital T2 hyperintensity o Often bilateral, not necessarily symmetrical o T2 high signal, variable swelling; reduced diffusion, gad enhancement atypical • Vasculitis o Patchy T2 high signal & reduced diffusion o CTA or MRA possibly abnormal; catheter angio shows irregularity, narrowing

BITHALAMIC

en

LESIONS

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c:

Primary angiitis of CNS vs. secondary (drug-induced, SL£, PAN, Wegener, etc.) • Wernicke Encephalopathy o T2 high signal in dorsal medial nucleus of thalamus o Enhancement usually absent; may show variably reduced diffusion o Associated midbrain, mamillary body abnormalities may be seen • Osmotic Demyelination Syndrome o Extrapontine myelinolysis (EPM) often accompanied by central pontine myelinolysis o EPM commonly affects thalamus; external capsule; putamen; caudate nucleus o Typically very symmetrical • Encephalitis/Encephalopathy o Many encephalitides may affect thalami: EBV,Japanese encephalitis; West ile virus o Acute necrotizing encephalopathy (ANE): Affects infants, children; thalamic involvement common • Controversial if viral etiology vs. more likely immune-mediated or metabolic pathogenesis Helpful Clues for Rare Diagnoses • Creutzfeldt-]akob Disease (C]D) o May affect medial thalami & pulvinar, giving so-called hockey stick appearance o Thalamic involvement initially suggested to be typical of vC]D, but also described with sC]D

Arterial Ischemia

Diffusion usually reduced in C]D; no enhancement Paraneoplastic Syndromes o May cause symmetrical T2 hyperintensity in posterior thalamus o May mimic prion disease, but. diffusion usually not seen Inborn Errors of Metabolism o Krabbe Disease • Thalami typically dense on CT, have short T2 on MR o Wilson Disease • T2 high signal in thalami may be seen • More commonly involves putamina & caudate nuclei Mitochondrial Disorders o Often symmetric reduced diffusion o Involvement of gray & white matter Solvent Inhalation, Toxic Ingestion o Toluene may cause thalamic hypointensity due to iron deposition o

o

•

•

•

•

Alternative Differential Approaches • Bithalamic process in a child: ADEM; HIE; diffuse astrocytoma; encephalitis; inborn errors of metabolism; mitochondrial disease; toxin exposure; ANE • Bithalamic process in an adult: Deep venous thrombosis; arterial infarction; astrocytoma; vasculitis; C]D; paraneoplastic syndrome

Arterial Ischemia

I Axial OWl MR shows high 51 representing reduced diffusion in the bilateral thalami I:j] & occipital lobes, as well as the corpus callosum splenium. MRA showed no flow in PCAs. Diagnosis

was bilateral

PCA infarction.

Axial OWl MR shows bithalamic areas of • diffusion I:j] in an elderly patient with confusion, R > L hemiparesis, & abnormal eye movements. LBrge vessels were normal, and artery of Percheron inFarct was the diagnosis.

6 93

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edema, without hemorrhage.

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Absent vein of Calen flow void compared with normal sagillal sinus flow void 81. OWl was ~ in the thalami, related to venous infarct (not shown).

(Left) Coronal flAIR MR in a child shows asymmetrical hyperintensity in the thalami =.1 as well as areas of t Sf involving the subcortical V-fibers 81. Patchy enhancement was present, but no ~ diffusion. LP: t Protein & lymphocytes. (Right) Axial T2WI MR in a patient with cognitive decline & left hemibody paresthesia shows asymmetrical enlargement & T2 hyperintensity of the thalami, right caudate, & putamen in this patient

Anaplastic astrocytoma.

HIE, Term Neonate (Left) Axial T2WI MR shows severe swelling and hyperintensity in the thalami ~ in a neonate who had poor Apgar scores after a complicated delivery. Reduced diffusion was also present. (Right) Axial OWl MR shows ~ diffusion of the thalami as well as diffusely in the cerebral

=

cortex in a patient

who

suffered profound hypotension after aortic dissection & rupture. No significant

6 94

Venous

(Left) Axial NECT shows edema in bilateral thalami & right caudate with parenchymal & intraventricular hemorrhage t Density in the internal cerebral veins 81 & straight sinus P.:i'l represent deep venous thrombosis. (Right) Axial T2WI MR shows bithalamic & corpus striatum

ADEM

I

Venous Ischemia/Deep Thrombosis

swelling

or mass

effect is present at this lime.

Diffuse Astrocytoma/Gliomatosis Cerebri

BITHAlAMIC

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lESIONS

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Acute Hypertensive Encephalopathy, PRES

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=

(Left) Axial FLAIR MR shows t 51 in the thalami & subcortical WM of the parietaf lobes 81. No enhancement

or

+

diffusion

was present. The patient was a liver transplant recipient & had renal disease. (Right) Axial FLAIR MR shows a bithalamic mass with

=

surrounding vasogenic edema. The lesion enhanced intensely & homogeneously post-gadolinium and showed mildly reduced diffusion centrally on the basis of high cellularity.

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(Left) Axial T2WI MR shows symmetrical t 51 in the medial thalami bilaterally without ! diffusion or enhancement. Periaqueductal gray matter also showed t 51. The patient was on TPN & responded rapidly to thiamine. (RighI) Axial OWl MR shows! diffusion in the thalami in a /I hockey stick" pallern in a patient with rapidly progressive dementia. Note! diffusion in the caudate nuclei & putamina, as well as right

=

=

temporal

Paraneoplastic

Syndromes

cortical

ribbon

E:I.

Krabbe Disease (Left) Axial FLAIR MR shows fairly symmetrical t 51 in the thalami, caudate nuclei, & frontal WM in a patient with rapidly progressive dementia & a movement disorder. No ! diffusion was present. Work-up eventually led to a diagnosis of non-small cell lung carcinoma & a paraneopJaslic syndrome that improved after treatment of the tumor. (Right) Axial T2WI MR shows symmetrical .1- 51 in B thalami in a patient with Krabbe disease. The thalami were dense on N[eT.

=

I 6 95

"PULVINAR

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DIFFERENTIAL DIAGNOSIS Common • Creutzfeldt-]akob Disease (C]D) • Creutzfeldt-]akob Disease, Variant (vC]D) Less Common • Fabry Disease • Thalamic Infarct (Mimic) • Neoplasms (Mimic) • ADEM (Mimic) Rare but Important • Periventricular Leukomalacia • Status Epilepticus

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • "Pulvinar sign": T2 hyperintensity in bilateral pulvinar, most sensitive for vC]D • T1 hyperintensity in pulvinar also called "pulvinar sign" (Fabry disease) Helpful Clues for Common Diagnoses • Creutzfeldt-]akob Disease (C]D) o Rapidly progressive, fatal neurodegenerative disease o Prion protein accumulates in neurons o 85% of cases sporadic; 15% genetic or familial o Infectious/iatrogenic cases, including vC]D, < 1% o , T2 in basal ganglia (BG), thalamus, cortex o FLAIR& DWI MR most sensitive

I 6 96

=-

=

Axial FU\/R MR shows abnormal hyperintensity involving the pulvinar medial thalami, putamen & caudate, characterisUc for C/D. Thalamic involvement is less commonly seen than in velD.

SIGN" • Creutzfeldt-]akob Disease, Variant (vC]D) o Bilateral T2 pulvinar hyperintensity o ± , T2 dorsomedial thalami, periaqueductal gray, caudate nuclei Helpful Clues for Less Common Diagnoses • Fabry Disease o Multisystem X-linked disorder with renal & cardiac dysfunction and stroke o T1 hyperintensity in bilateral pulvinar o CT may show mineralization in pulvinar o May see ischemia, white matter (WM) lesions, & vertebrobasilar dolichoectasia • Thalamic Infarct (Mimic) o Artery of Percheron infarct & internal vein thrombosis: Bilateral T2 hyperintensity o HIE may affect only deep gray nuclei o DWI bright in acute setting • Neoplasms (Mimic) o Lymphoma or astrocytoma may cause bilateral thalamic T2 hyperintensity • ADEM (Mimic) o T2 hyperintensity in bilateral thalami o WM lesions typically also present Helpful Clues for Rare Diagnoses • Periventricular Leukomalacia o Pulvinar hyperintensity may be seen in association with PVL o Thalamic involvement suggests more severe motor & mental disabilities • Status Epilepticus o Peri-ictal T2 hyperintensity, DWI restriction in bilateral pulvinar, often with hippocampal & cortex involvement

=

Axial FU\/R MR shows bilateral hyperintensities in the posterior UJa/ami, "pulvinar sign" of vCID. FU\IR & OWl MR are most sensiUve for diagnosis. vCIO is primarily seen in the United Kingdom.

"PULVINAR

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(Left) Axial OWl MR shows

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(JJ

the pulvinar bilaterally EE characteristic for velD. vClO is caused by ingestion of beef produc15 infected with

C

symmetric

bovine

OWl restriction

spongiform

encephalopathy. It is rare, making up < 1% of all Clo cases. (Right) Axial TI WI MR shows symmetric hyperintensity in the pulvinar the "pulvinar sign" of Fabry disease. Hyperintensity is also noted in the basal ganglia.

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(Left) Axial FlAIR MR shows hyperinlensily in the medial thalami classic location

=-

for major penetrating

artery

of Percheron stroke. Some patients have a dominant large posterior perforating artery instead of multiple

smaller ones. When these arteries are occluded, devastating midbrain & thalamic

infarcts may occur.

OWl is positive in the acute selling. (Right) Axial T2WI MR shows asymmetric bithalamic hyperintensity

H2.

Astrocytoma

was found

at biopsy.

ADEM (Mimic)

Periventricular leukomalacia (Left) Axial FlAIR MR shows symmetric

hyperinlensity

in

the pulvinar 1:]. Note involvement of the occipital subcortical white matter E:I. ADEM involves the deep gray structures more often than other demyelinating processes. 1l is typically bilateral but asymmetric. (Right) Axial T2WI MR shows hyperintensity in the pulvinar I:] of the thalamus bilaterally in this patient with spastic quadriparesis & PVL. Note wavy ventricular margins, typical of PVL.

I 6 97

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DIFFERENTIAL DIAGNOSIS Common • Diffuse Astrocytoma, Low Grade • Brainstem Glioma, Pediatric less Common • Lipoma • Neurofibromatosis Type 1 • Chiari 2 Rare but Important • Cavernous Malformation • Progressive Supranuclear Palsy

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Tectum is dorsal portion of midbrain, dorsal to cerebral aqueduct • Tectum includes superior & inferior colliculi & periaqueductal gray matter Helpful Clues for Common Diagnoses • Diffuse Astrocytoma, Low Grade o Nonenhancing T2 hyperintense mass o Supratentorial 2/3, infratentoriall/3 o 50% of "brainstem gliomas" are diffuse astrocytomas • Brainstem Glioma, Pediatric o Heterogeneous group of gliomas o Tectal glioma: Most indolent, often only need CSF diversion • Expands tectum & obstructs aqueduct • T2 hyperintense mass ± enhancement

Helpful Clues for less Common Diagnoses • Lipoma o Well-delineated lobulated extra-axial mass with fat attenuation/intensity o Interhemispheric fissure most common location (30-40%) o 20-25% pineal region (attached to tectum) • Neurofibromatosis Type 1 o Focal areas of signal intensity (FASI) in white matter & deep gray matter • Typically involve globus pallidus • May involve brainstem o Tectal gliomas are associated with Nfl • Chiari 2 o Complex malformation of hindbrain associated with neural tube closure defect, usually lumbar myelomeningocele o Small posterior fossa, "beaked" tectum o "Towering" cerebellum protrudes up through incisura, compresses tectum Helpful Clues for Rare Diagnoses • Cavernous Malformation o Heterogeneous "popcorn" mass with T2 hypointense rim (hemosiderin) o Brainstem lesions common when multiple • Progressive Supranuclear Palsy o Midbrain, superior colliculi, & superior cerebellar peduncle atrophy o T2 hyperintensity in periaqueductal gray o Midbrain atrophy described as "penguin" & "hummingbird" sign on sagittal MR o "Morning glory sign": Concave lateral tegmentum on axial images

I 6 98

Sagittal T2WI MR shows a hyperintense mass involving the tectal plate along the posterior 3rd ventricle ~ in this young adult. Sagittal imaging is helpful 10 define

lesions in this location.

Axial T2WI MR shows a hyperintense mass involving the tectal plate Lesions in this location often cause

obstruction shunting.

of

=_

the

cerebral aqueduct,

requiring

TECTAL (QUADRIGEMINAL

PLATE) LESION Ql

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(Left) Sagittal TI WI MR shows a homogeneous mass arising from the superior colliculus a tectal glioma. Tectal gliomas are the most benign of the brainstem gliomas. They often have an indolent course & usually only require CSF diversion. They are most often pilocytic astrocytomas. (Right) Sagittal T1WI MR shows a hyperintense mass along the inferior collicu/us typical location for a collicular lipoma. Fat suppression confirms the diagnosis.

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Neurofibromatosis

Type 1

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Chiari 2 (Left) Axial FLAIR MR shows multiple foci of abnormally increased signal (FASt) in the brainslem & cerebellum, typical of neurofibromatosis type 7. FASI are most common in the globus pallidus but may also be seen in the brainstem. (Right) Sagittal T1 WI MR shows a beaked tectum E!ll characteristic of Chiar; 2. Note the smaJl posterior fossa with caudal displacement of brainstem & 4th ventricle IJ:.:l as well as the cerebellar nodulus.

=

Cavernous Malformation (Left) Axial T2WI MR shows a hemorrhagic midbrain cavernous

malformation

=

with low signal blood products & surrounding edema related LO a recent hemorrhage. Blood products of varying ages result in a II popcorn II or "mulberry" appearance. (Right) Sagittal T2WI MR shows a severely atrophic tectal plate in this patient with PSP.PSP is characterized by midbrain & superior colficufus atrophy. Parkinsonian-like symptoms are common in PSP.

I 6 99

MIDBRAIN lESION

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Common • Cerebral Ischemia-Infarction, Acute • Trauma (Diffuse Axonal Injury, Contusion) • Demyelinating Disease (MS, ADEM) • Metastasis • Cavernous Malformation • Enlarged Perivascular Spaces • Wallerian Degeneration less Common • Aqueductal Stenosis • Brainstem Tumor o Tectal Glioma o Low Grade Neoplasm • JPA, Diffuse Fibrillary Astrocytoma o High Grade Neoplasm • Anaplastic Astrocytoma, GBM, PNET • Wernicke Encephalopathy • Mitochondrial Cytopathy Rare but Important • Infection o Progressive Multifocal Leukoencephalopathy (PML) o Abscess, Encephalitis • Vasculitis • Intracranial Hypotension • Progressive Supranuclear Palsy (PSP) • Parkinson Disease • Amyotrophic Lateral Sclerosis (ALS) • Drug Toxicity

•

•

•

•

•

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Most common midbrain lesions are ischemic, traumatic, demyelinating, vascular, or neoplastic • Hemorrhage usually due to trauma, vascular malformation, or hemorrhagic metastasis; hypertensive hemorrhage rare in midbrain

I 6 100

Helpful Clues for Common Diagnoses • Cerebral Ischemia-Infarction, Acute o Acute onset of clinical symptoms, often hemiparesis (corticospinal tracts), cranial neuropathy (nuclei of III, IV; a nucleus of V), &/or ataxia (red nucleus) o Presence of reduced diffusion: High SI on DWI, low SI on ADC map

Often accompanied by lesion of basilar artery, so consider MRA or CTA Trauma (Diffuse Axonal Injury, Contusion) o Appropriate clinical history; FLAIR,DWI particularly helpful to assess for edema (cytotoxic &/or vasogenic); GRE to assess for hemorrhage o Brainstem DAI typically dorsolateral, usually seen with hemispheric & callosal involvement; check for additional sites of injury Demyelinating Disease (MS, ADEM) o T2 bright lesions typically without reduced diffusion or GRE abnormality, often enhance post-gadolinium o Assess rest of brain for additional white matter (WM) lesions o Consider MR of optic nerves, spinal cord Metastasis o Typically enhance, associated with vasogenic edema; additional lesions often present in brain, meninges, or bone o May be hemorrhagic Cavernous Malformation o Often bright on T1 & T2WI; "mulberry-like" morphology; >SI on GRE o Associated developmental venous anomaly (DVA)may be present Enlarged Perivascular Spaces o Usually seen at base of cerebral peduncles o Follow CSF on all MR seq uences Wallerian Degeneration o Acute: Variable> diffusion and t SI on T2 o Chronic: Volume loss; variable T2 SI o

DIFFERENTIAL DIAGNOSIS

III

Helpful Clues for less Common Diagnoses • AqueductaI Stenosis o Cause of "congenital" hydrocephalus: May be due to a web or adhesion; often post-infJammatory or post-intraventricular hemorrhage o Assess tectum carefully on axial T2 & FLAIRto exclude subtle nonenhancing tectal glioma • Brainstem Tumor o Multiple histologies can affect midbrain & other parts of brainstem o Imaging varies with tumor histology o "Tectal gliomas": Typically confined to tectum, nonenhancing, present with chronic hydrocephalus

MIDBRAIN

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LESION

c:

• Generally better prognosis then other brainstem tumors; associated with NFl • Wernicke Encephalopathy o Thiamine deficiency; most commonly seen in alcoholics; also malnutrition, malabsorption, HIV/AIDS o Classic clinical triad: Ataxia, encephalopathy, oculomotor dysfunction o Symmetrical t T2 SI variably involves periaqueductal gray matter, dorsomedial thalami, mamillary bodies o • Diffusion, post-gad enhancement variably present acutely • Mitochondrial Cytopathy o Typically affects deep gray nuclei of cerebrum &/or gray matter structures of brainstem in symmetrical fashion o • Diffusion, t T2 SI typically present with acute flare of disease o t Lactate peak may be seen with MR spectroscopy Helpful Clues for Rare Diagnoses • Infection o Progressive multifocal leukoencephalopathy (PML) • Usually severely immunocompromised patients (AIDS, organ transplant, chemotherapy) • Classic: WM lesions without enhancement or mass effect • May cause pattern of "small dots" in WM or brainstem that eventually coalesce into more typical geographic lesions

Cerebral Ischemia-I nfarction,

Acute

Pyogenic abscess: Central. diffusion; also ring enhancement, vasogenic edema Vasculitis o Nonspecific t SI on T2WI; often I diffusion Intracranial Hypotension o Downward displacement of midbrain, loss of cisterns; "folding" if severe Progressive Supranuclear Palsy (PSP) o Atypical Parkinsonian syndrome: Supranuclear ophthalmoplegia, pseudobulbar palsy, dysarthria, postural instability, frontotemporal dementia o Neuropathological hallmark: Midbrain atrophy; tau + aggregates o MR: Midbrain atrophy; variable midbrain T2 hyperintensity Parkinson Disease a Imaging findings typically subtle; possible • volume of substantia nigra, • hypointensity of lateral margin of substantia nigra Amyotropic Lateral Sclerosis (ALS) o Degenerative disease of upper and lower motor neurons in the motor cortex, brainstem, and spinal cord o Imaging hallmark: t T2 SI of corticospinal tracts; no mass effect, enhancement Drug Toxicity o Notably metronidazole; symmetrical t T2 SI, variable. diffusion o Dentate nuclei usually involved o

• •

•

•

•

•

Trauma (Diffuse Axonal Injury, Contusion)

I Axial OWl MR in a 71 year old shows high signal intensity representing reduced diffusion in the midbrain 1GB This lesion sharply respects midline An AOC map confirmed lrue reduced diffusion.

Axial NEG shows a shear hemorrhage I:!lI in the right dorsolateral midbrain. This paUent with severe head trauma has evidence of scalp injury 8J and post-traumatic SAIl ffi among other injuries.

6 101

MIDBRAIN lESION

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=-

enhanced

&

was

symplOmaticallyacute. Periventricular

white maller

lesions ~ are also present in this young woman with MS. (Right) Axial NEeT shows a focal hemorrhage in the right midbrain with surrounding edema Additional hemorrhagic lesions are present in the temporal lobe ~ This patient had metastatic

melanoma.

(Left) Axial T2WI MR shows

a well-circumscribed lesion 1::1 with a hemosiderin rim & heterogeneous internal signal due 10 blood products. The trunk of a large associated OVA that drains brainslem and cerebellum Ii8 is also seen. (Right) Axial f2WI MR shows bilateral linear T2 bright structures at the base of the cerebral peduncles bilaterally These followed CST on all sequences. Small perivascular or V;rchow-Robin spaces are common in this location.

=.

(Left) Axial T2WI MR shows

a hyperintense & mildly atrophic left cerebral peduncle This patient had a prior left MCA stroke, & left temporal atrophy is present. (Right) Sagittal T2WI MR shows a funnel-shaped aqueduct of Sylvius normal 4th ventricle thinned & stretched corpus callosum Sl & downward displacement of the floor of the 3rd ventricle ~ The

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aqueduclalobstruction

I 6 102

is

due to a web or adhesion, and no mass is present.

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MIDBRAIN lESION

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Tectal Glioma (Left) Sagittal T2WI MR shows a high signal inlensily mass ~ confined 10 lhe tectum, causing severe obslructive hydrocephalus. There was no associated enhancement or surrounding edema. (Rig"') Axial T2WI MR shows an expansile mass of lhe midbrain =:I lhat exlends well beyond lhe tectum.

There is no

associated edema. Surprisingly, no hydrocephalus is present. The mass enhanced intensely & homogeneously. Palhology confirmed IPA.

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(Left) Axial FLAIR MR shows an expansile lesion involving the dorsal midbrain =:I. The lesion has an ill-defined interface with normal midbrain. Severe obstructive hydrocephalus is presenl 81 wilh lransependymal flow of CSF~. (Rig"') Axial FLAIR MR shows symmetrical t 51 of the dorsal midbrain & periaqueductal gray matter =:I as well as t Sloflhe mamillary bodies 81. This patient was severely malnourished & responded to thiamine

treatment.

(Left) Axial FLAIR MR shows symmetrical t 51of the dorsal midbrain & periaqueductaf

gray matter

=:I in a 2 year old.

The lesion demonstrated! diffusion & no enhancement. Additional symmetrical lesions were present in the putamina. (Right) Axial FLAIR MR shows patchy t T2 51in righl midbrain & cerebral peduncle, associated with mild volume loss. Addilional multifocal peripheral/subcortical WM lesions are present in the righltemporallobe.

I 6 103

SECTION 7 Infratentorial Brain Parenchyma Anatomically Based Differentials 1-7-2 1-7-4

Large Brainstem Small Brainstem Pontine Lesion Medulla Lesion Infratentorial Midline Cyst Cerebellar Atrophy Cerebellar Mass Vermis Mass Low Cerebellar Tonsils

1-7-6

1-7-10 1-7-14 1-7-18 1-7-22 1-7-28 1-7-32

Generic Imaging Patterns "Cystic-Appearing"

Posterior Fossa Lesion

1-7-34

Clinically Based Differentials Posterior Fossa Neoplasm, Posterior Fossa Neoplasm,

Adult Pediatric

1-7-40 1-7-44

LARGE BRAINSTEM

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DIFFERENTIAL DIAGNOSIS Common • Brainstem Glioma • Hypertensive Intracranial Hemorrhage Less Common • Intracranial Hypotension • Osmotic Demyelination Syndrome • Cerebral Ischemia-Infarction, Acute • Demyelination • Encephalitis • Cavernous Malformation

Rare but Important • Metastases, Parenchymal • Syringobulbia • Hypertrophic Olivary Degeneration • Hemangioblastoma

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Brainstem Glioma o Pontine> medulla> mesencephalic glioma o Enlarged, 1'2 hyperintense mass • Hypertensive Intracranial Hemorrhage o Pons hemorrhage in a hypertensive patient o Basal ganglia> thalamus> pons Helpful Clues for Less Common Diagnoses • Intracranial Hypotension o Downward displacement of brain through incisura ("slumping" midbrain) • "Fat pons" can mimic neoplasm! o ± Dural enhancement, SDH

Brainstem

Glioma

• Osmotic Demyelination Syndrome o Typically involves central pons 01'2 hyperintense, ± enhancement, DWI • Cerebral Ischemia-Infarction, Acute o "Top of the basilar": Midbrain & thalamic infarcts ± temporal & occipital lobes o May have midbrain, pons, or medulla ischemia related to vertebrobasilar perforator or cerebellar artery disease 01'2 hyperintense edema, DWI bright • Demyelination o Includes multiple sclerosis & ADEM o Brainstem enlargement with acute lesions o Focal 1'2 hyperintensity ± enhancement • Encephalitis 01'2 hyperintensity & enhancement typical o Etiologies include Listeria monocytogenes, enterovirus, West Nile virus, herpes, EBV, adenovirus, Japanese encephalitis • Cavernous Malformation o Heterogeneously bright on 1'1 & 1'2 o Hemosiderin rim classic Helpful Clues for Rare Diagnoses • Metastases, Parenchymal o Enhancing mass with edema o Multiple lesions common • Syringobulbia o Extension of cervical syrinx into brainstem • Hypertrophic Olivary Degeneration o Unilateral or bilateral 1'2 hyperintensity & enlargement of medullary olives • Hemangioblastoma o Nodular enhancement ± cyst

Hypertensive

Intracranial

Hemorrhage

I 7 2

Axial T2WI FS MR shows expansion and hyperintensity of the pons by a diffusely infiltraUng glioma. Note that the pons engulfs the basilar artery 1:;'.1 typical of these

tumors.

Axial NEeT the pons

shows a hypertensive hemorrhage within Note that ale blood has dissected into the

=.=.

4th ventricle Extension of blood into the venlJicular system is common.

LARGE BRAINSTEM

en

c" : III

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Intracranial Hypotension

..•

Osmotic Demyelination Syndrome

III

(Lefl) Sagillal T7 c+ MR shows classic intracranial hypotension with a "slumping midbrain" ffi dural engorgement, & downward tonsillar displacement. Signal in the brainstem is normal, which helps differentiate this from other etiologies. (RighI) Axial T2WI MR shows high signal in the centra! pons with peripheral sparing. Preservation

Cerebral

Ischemia-Infarction,

Acute

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acutely.

Demyelination (Left) Axial T2WI MR shows acute pontine

ischemia

related to occluded pontine perforating arteries off the basilar artery. There is mild swelling & subtle high signal in the pons. Brainstem

=

ischemia

often respects

midline.

OWl is positive

acutely. (RighI) Axial T2WI MR shows a large multiple sclerosis plaque in the pons BI & cerebellum 1::1.

Brainstem lesions are commonly to

seen in addition

supratentorialles;o17s.

The

middle cerebellar peduncle is often involved.

Cavernous Malformation (Lefl) Axial T7 WI MR shows hemorrhage in the pons secondary to a pontine cavernoma.

Even in a

hypertensive patient, follow-up imaging to exclude an underlying vascular lesion is helpful. (RighI) Axial T2WI MR shows bilateral

inferior

olivary nuclei hyperintensity & hypertrophy ffi following radiotherapy to a midbrain AVM. This rare degeneration results from an insulllO the dcntato-rubro-olivary pathway. The causative lesion is often in the pons or midbrain.

I 7 3

SMALL BRAINSTEM

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DIFFERENTIAL DIAGNOSIS Common • Cerebral Infarction, Chronic • Wallerian Degeneration less Common • Multiple Sclerosis, Chronic • Multiple System Atrophy o Olivo pontocerebellar Degeneration o Striatonigral Degeneration Rare but Important • Friedreich Ataxia (Spinocerebellar Ataxia) • Progressive Supranuclear Palsy • Congenital o Prematurity-Related Atrophy o Congenital Muscular Dystrophy o Pontocerebellar Hypoplasias

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Cerebral Infarction, Chronic o May be lacunar, territorial, related to small vessel disease, or hypertensive hemorrhage o Brainstem supplied primarily by cerebellar arteries & vertebrobasilar perforators o Brainstem T2 hyperintensity & atrophy • Wallerian Degeneration o Chronic infarct along corticospinal tract leads to volume loss of cerebral peduncle, ventral pons, & medullary pyramid o Typically T2 hyperintense

Cerebral

I 7

Infarction,

the prominent 4th ventricle related to the

4

Helpful Clues for Rare Diagnoses • Friedreich Ataxia (Spinocerebellar Ataxia) o Severe atrophy of spinal cord (posterior) o Mild atrophy of medulla & vermis • Progressive Supranuclear Palsy o Midbrain, collicular & superior cerebellar peduncle atrophy o T2 hyperintensity in periaqueductal gray o Midbrain atrophy described as "penguin", "hummingbird", & "morning glory sign" • Prematurity-Related Atrophy o Cerebellar> brainstem atrophy • Congenital Muscular Dystrophy o Kinked or notched brain stem • Pontocerebellar Hypoplasias o Cerebellar & brainstem hypoplasia

Wallerian

Chronic

Axial T2WI MR shows multiple hyperintensilies within the pons related to chronic small vessel ischemia. Note atrophy.

Helpful Clues for less Common Diagnoses • Multiple Sclerosis, Chronic o Brainstem atrophy ± T2 hyperintensity • Multiple System Atrophy o Includes olivopontocerebellar atrophy, striatonigral degeneration, & Shy-Drager o MR features overlap • Brainstem & cerebellar atrophy • Pons, middle cerebellar peduncle r T2 • Putamen: T2 hypointensity o MSA-C: Cerebellar signs predominate o MSA-P: Parkinsonism predominates o Olivopontocerebellar Degeneration • Pons T2 cruciform hyperintensity • Pons, olives, & cerebellar vermis atrophy o Striatonigral Degeneration • • T2 signal in putamen & midbrain

brainslem

Degeneration

Axial T2WI MR shows hyperintensity 8, atrophy of the cerebral peduncle ~ related to wallerian degeneration secondary to a large remote right MCA distribution infarct.

SMAll

BRAINSTEM III

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Multiple Sclerosis,Chronic

III

(Le(t) Axial FLAIR MR shows mulli{ocal hyperinlensilies in the brainslem &. subcortical while maller. Note associated atrophy o( the brainstem related to chronic MS in this young patient. (Right) SagiLtal T1WI MR shows a small pons & cerebellar vermian atrophy in this patient with cerebellar signs & clinical diagnosis o( MSA-C. Imaging (in dings overfap between MSA subtypes. Brainstem & cerebellar atrophy with sparing o( the cerebral hemispheres is typical.

Olivo pontocerebellar

Degeneration

:::l

Olivopontocerebellar Degeneration (Left) SagiLtal T1 WI MR shows striking atrophy o( the pons, medulla, & cerebellum. Note normal appearance o( the cerebral hemispheres in this classic imaging o( sporadic olivoponlocerebellar atrophy (MSA-C subtype). (Right) Axial T2WI MR shows cruciform hyperinlensily in pons, "hot cross bun" sign ~ related to loss o( myelinated transverse pontocerebellar (ibers & neurons in pontine raphe. Note atrophy o( pons & cerebellum, typical o( MSA.

(Left) Axial T2WI MR shows typical abnormal T2 hypointensity in the substantia nigra & a small midbrain in a patient with slrialonigral degeneration, a type o( MSA. MSA is characterized by dysautonomia, parkinsonism, & cerebellar atrophy. (Right) SagiLtal T1WI MR shows marked atrophy o( the rostral midbrain causing a "hummingbird" or "penguin" sign. Note also the superior collicu/us & cerebellar atrophy, classic findings o( PSP.

=

=-

I 7 5

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DIFFERENTIAL DIAGNOSIS Common • Arteriolosclerosis (Ischemic Rarefaction) • Cerebral Ischemia-Infarction, Acute • Hypertensive Intracranial Hemorrhage • Brainstem Tumor • Vascular Lesion o Capillary Telangiectasia, Cavernous Malformation, AVM Less Common • Demyelinating Disease (MS, ADEM) • Malignant Neoplasm o Metastasis, High Grade Tumor, Lymphoma • Pilocytic Astrocytoma • Wallerian Degeneration • Acute Hypertensive Encephalopathy, PRES • Focal or Multifocal Infection o Pyogenic Abscess, Tuberculoma, PML • Osmotic Demyelination Syndrome • Neurofibromatosis Type 1 Rare but Important • Brainstem Encephalitis • Vasculitis • Multiple System Atrophy • Radiation Necrosis • Mitochondrial Disorder • Maple Syrup Urine Disease • Infiltrative Disorder o Langerhans Cell Histiocytosis; Neurosarcoid; Whipple Disease

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Pontine lesions that present acutely are typically ischemic or hemorrhagic • Diffuse astrocytomas present in a more insidious fashion

I 7 6

Helpful Clues for Common Diagnoses • Arteriolosclerosis (Ischemic Rarefaction) o Ischemic rarefaction of pons very common in older patients with ASVDrisk factors o Mild diffuse t SI on T2WI without mass effect, enhancement, or J, diffusion • Cerebral Ischemia-Infarction, Acute o Pontine infarct typically respects the midline & shows reduced diffusion • Consider CTA or MRA to assess vertebrobasilar circulation

• Hypertensive Intracranial Hemorrhage o Hypertensive hemorrhages usually central o Acute pontine hemorrhage usually hypertensive, but may be due to cavernoma or AVM o CTA or MR/MRA to look for AVM • Brainstem Tumor o Massive expansion of pons, "engulfing" basilar artery, often nonenhancing o Typically diffuse fibrillary astrocytoma • Vascular Lesion o Capillary telangiectasia: Usually small, asymptomatic; "feathery" enhancement; signal loss on GRE; common in pons Helpful Clues for Less Common Diagnoses • Demyelinating Disease (MS, ADEM) o Often involvement of middle cerebellar peduncles; incomplete ring enhancement o Additional lesions in corpus callosum, hemispheric white matter (WM), spinal cord, optic nerves • Malignant Neoplasm o High grade tumor (GBM, PNET) often accompanied by edema, irregular enhancement, increased CBV o Metastases to pons associated with edema, often other enhancing lesions of brain parenchyma, dura, bone o Lymphoma usually homogeneously enhances, may show mildly J, diffusion • Pilocytic Astrocytoma o Focal enhancing lesion without edema • Wallerian Degeneration o Acute: Variable • diffusion and t SI on T2 o Chronic: Volume Joss; variable T2 SI • Acute Hypertensive Encephalopathy, PRES o Most commonly involves parietooccipital subcortical WM o Infratentorial T2 hyperintensity often present in pons, cerebellum o Best appreciated on FLAIR;usually no enhancement or DWI abnormality • Focal or Multifocal Infection o Pyogenic abscess will typically reduce diffusion, whereas tuberculoma may not o PML often causes multiple small dots of T2 hyperintensity in the brainstem • Osmotic Demyelination Syndrome o Commonly involves centra] pons, spares corticospinal tracts, may show. diffusion

en ,...

PONTINE lESION

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• Neurofibromatosis Type 1 o Common in dorsal pons, due to dysmyelination/myelin vacuolization o No mass effect, enhancement Helpful Clues for Rare Diagnoses • Brainstem Encephalitis o Multiple causative agents including listeria monocytogenes, West Nile, HSV 1 o Acute presentation, swelling, irregular enhancement, variable> diffusion • Vasculitis o May mimic demyelinating lesions; look for reduced diffusion, vascular irregularity, irregular enhancement • Multiple System Atrophy o Sporadic neurodegenerative disorder encompasses olivopontocerebellar atrophy, striatonigral degeneration, & Shy-Drager o When Parkinsonism predominates, MSA-P; when cerebellar signs predominate, MSA-C o Imaging may show putaminal volume loss, "slit-like" lateral putaminal T2 hyperintensity (MSA-P), or "hot cross bun" appearance, atrophy of pons/middle cerebellar peduncles (MSA-C) • Radiation Necrosis o Correlate with history; look for evidence of a port (fatty marrow in skull base) o May occur many years after radiation • Mitochondrial Disorder o May be congenital or acquired (e.g., perinatal exposure to zidovudine)

Symmetrical T2 hyperintensity that often involves hemispheric WM, deep gray nuclei, & pons o Often> diffusion acutely; volume loss in chronic phase • Maple Syrup Urine Disease o Neonate: Cerebellar WM, brainstem > supratentorial edema • Infiltrative Disorder o Enhancing lesions typical o

Other Essential Information • MR is study of choice for pontine pathology • Parallel imaging techniques may be helpful to reduce susceptibility artifacts that can obscure pontine pathology

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Alternative Differential Approaches • Pontine lesion in a child: Demyelination (ADEM), brainstem encephalitis, or diffuse astrocytoma; metabolic or mitochondrial disorder • Pontine lesion in an adult: Likely to be ischemic or hemorrhagic o Hypertensive hemorrhage in older adult o Vascular malformation (AVM, cavernoma) in young adult • Enlargement of pons: Diffuse astrocytoma; brainstem encephalitis; severe ADEM, PRES • Atrophy of pons: Prior injury (ischemic, hemorrhagic, infectious, metabolic); walJerian degeneration; MSA; other neurodegenerative disorder

Cerebral

Axial T2WI MR shows i"-defined central pontine T2 high signal in all elderly man. Cerebrum demonstrated volume loss as well as pedvenlricular and subcortical while matter T2 hyperintensities.

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Axial OWl MR shows reduced diffusion ill the left pons thai respects the midline in a patienl wiU, aCLIte onset right hemiparesis. A 2nd area of acute infarcll!l:1 is seen in the temporal lobe.

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(Lefl) Axial NECT shows central pontine high density B consistent with acute hemorrhage. This hypertensive patient had an abrupt onset of headache followed by loss of consciousness. (RighI) Axial FLAIR MR shows massive expansion of the pons in a young girl with gradual onset di(ficulty walking & cranial neuropathy. The pons is diffusely bright, & the basilar artery SI appears to be "engulfed" by tumor. The lesion did not enhance or

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region.

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I 7 8

enhancement or reduced diffusion. (RighI) Axial T2WI MR shows multiple large, bright, somewhat ill-defined lesions in the pons & middle cerebellar peduncles. Several of the lesions showed mild enhancement but no reduced diffusion. This child was subsequently diagnosed with ADEM.

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Pilocytic Astrocytoma (Left) Axial T2WI MR shows a centrally hemorrhagic lesion with a low signal intensity rim & surrounding vasogenic edema. The pons is moderately expanded in this /5 year old. Biopsy confirmed GBM. (Right) Axial TI C+ MR shows a fairly weJl-circumscribed low Silesian in the dorsal pons with central enhancement~. The lesion was T2 bright, & there was no associated edema. Biopsy showed juvenile pilocytic astrocytoma in this young boy.

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Osmotic Demyelination Syndrome (Left) 5agillal TI C+ MR shows a large rim-enhancing lesion in the dorsal pons. A "daughter" lesion !1m is beginning to form. There was associated vasogenic edema & central reduced diffusion. Pyogenic abscess. (Right) Axial FLAIR MR shows central pontine high·signal intensity, with sparing of a thin peripheral rim of pontine tissue as well as the descending corticospinal tracts There was reduced diffusion & no enhancement in the lesion. CPM.

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Infiltrative Disorder (Left) Axial T2WI MR shows marked atrophy of the pons & visualized cerebellum. The pons shows a "hot cross bun U appearance due to selective loss of myelinated transverse pontocerebellar fibers & neurons in the pontine raphe. Corticospinal tracts are preserved. (Right) Axial T1 C+ MR shows irregular linear & nodular enhancement throughout the pons, extending to middle cerebellar peduncles & cerebellum. High signal on T2 was present. Neurosarcoidosis.

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Common • Lateral Medullary Infarct • Wallerian Degeneration • Demyelinating Lesion (MS, ADEM) • Vascular Lesion o Cavernous Malformation; AVM • Brainstem Glioma, Pediatric o Diffuse Fibrillary Astrocytoma o Exophytic Cervicomedullary Glioma Less Common • Brainstem Neoplasm, Adult o Glioma, High or Low Grade o Hemangioblastoma o Metastasis, Lymphoma • Vasculitis • Medial Medullary Infarct • Infection (Abscess, Tuberculoma, • Syringobulbia

Rare but Important • Hypertrophic Olivary Degeneration • Infiltrative Disorders (Langerhans Cell Histiocytosis, Neurosarcoid) • Mitochondrial Disorder • Viral Encephalitis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Acute onset of cranial nerve deficits and Horner syndrome in an older patient suggests medullary infarction o CT suboptimal for evaluation of medulla; MR with diffusion is indicated o Posterior circulation should be assessed intra- & extracranially with CTA or MRA o Vertebral artery dissection a consideration in younger patient; add Ax Tl with fat-sat • Reduced diffusion in focal medullary lesion usually due to acute medullary infarction • Volume loss of medullary pyramides) usually due to wallerian degeneration o Look for remote infarct • Expanded medulla? Neoplasm> infarction, demyelination, infection

I 7 10

•

•

PML)

Helpful Clues for Common Diagnoses • Lateral Medullary Infarct o Reduced diffusion; often subtle T2 abnormality in acute phase

Typically dorsolateral, due to occlusion of vertebral artery or PICA; check CTA or MRA o Wallenberg syndrome: Deficits in pain/temperature sense, dysphagia, hoarseness, vertigo, diplopia, Horner syndrome Wallerian Degeneration o Acute wallerian degeneration may lead to medullary pyramid T2 hyperintensity, mildly reduced diffusion o Chronic infarction along corticospinal tract leads to volume loss of medullary pyramid; variable T2 signal Demyelinating Lesion (MS, ADEM) o Usually associated with WM lesions in other parts of brain, may enhance, diffusion typically not reduced Vascular Lesion o Cavernous malformation may be associated with developmental venous anomaly; GRE hypointense o CTA or MRA may help to evaluate for high flow vascular malformation Brainstem Glioma, Pediatric o Diffuse infiltrative astrocytoma: Medullary expansion, t T2 SI, usually nonenhancing o Pediatric astrocytoma may also be exophytic from cervicomedullary junction • Dorsal or ventral; often enhancing o

DIFFERENTIAL DIAGNOSIS

•

•

Helpful Clues for Less Common Diagnoses • Brainstem Neoplasm, Adult o Medullary expansion, areas of irregular enhancement likely high grade glioma o Hemangioblastoma presents as nodular enhancement ± cyst • Usually in setting of VHL; look for other lesions in cerebellum, spinal cord o Focal enhancing lesion + associated edema: Consider metastasis, lymphoma • Vasculitis o Multifocal T2 lesions, variable ~ DWl o CTA or MRA may show vascular irregularity, but catheter angiography generally indicated o Often associated with systemic symptoms, abnormal CSF • Medial Medullary Infarct o Less common vertebrobasilar stroke syndrome

MEDULLA lESION

Classic Ipsilateral hypoglossal palsy, contralateral hem iparesis, contralateral lemniscal sensory loss • Infection (Abscess, Tuberculoma, PML) o Medullary pyogenic abscess rare; reduced diffusion, peripheral enhancement o Tuberculoma: Ring or nodular enhancement, central T2 hypointensity, diffusion variable o PML: Multifocal T2 abnormality, no mass effect, immunocompromised patient • Syringobulbia o Cervical syrinx may extend cephalad into medulla o Assess for Chiari 1 malformation, spinal cord tumor, other obstruction to CSF flow o

Helpful Clues for Rare Diagnoses • Hypertrophic Olivary Degeneration o Insult to dentato-rubro-olivary pathway o Classic symptom: Palatal tremor o Uni- or bilateral enlargement, T2 hyperintensity of inferior olivary nucleus o No reduced diffusion, no post-gad enhancement o Chronic phase: Possible volume loss • Infiltrative Disorders (Langerhans Cell Histiocytosis, Neurosarcoid) o T2 abnormality, irregular linear and nodular enhancement o Diffusion typically not reduced, vascular imaging studies normal • Mitochondrial Disorder o Symmetrical t T2 51, often ! diffusion

lateral

Medullary

May mimic medullary encephalitis, or vice versa • Viral Encephalitis o Typically symmetrical, nonspecific t 51on T2WI; variably! diffusion o Specific diagnosis usually made with CSF analysis o

Other Essential Information • MR is always the imaging study of choice for medullary pathology

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Alternative Differential Approaches • Medullary lesion with reduced diffusion o Typically medullary infarct; assess vertebrobasilar circulation o Occasionally seen with demyelination: Look elsewhere for typical lesions o May occur with mitochondrial disease or brainstem encephalitis (more diffuse, symmetrical) • Medullary lesion with GRE hypointensity o Typically cavernous malformation; give gadolinium to look for DVA o Other possibilities: Hemorrhage due to AVM,neoplasm, infection, prior trauma • Medullary lesion with gadolinium enhancement o Neoplasm, infection, demyelination • Medullary expansion o Usually seen with diffuse infiltrative astrocytoma in a child or young adult

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Glioma, High or low Grade

(Left) Axial T2WI MR shows a small, mildly hyperintense medullary pyramid ffi This patient had a left MCA stroke with right hemiparesis 1 year earlier. (Right) Axial T2WI MR shows extensive high signal in the central medulla ~ & the right medullary pyramid laC The lesion does not respect the midline or usual vascular boundaries. This patient had known MS & presented with subacute onset of left-sided weakness & lower cranial neuropathies.

(Left) Axial T2WI MR shows a well-circumscribed lesion in the dorsolateral medulla with peripheral hemosiderin staining There is central hyperintensity & subtle surrounding edema. The patient was acutely symptomatic & had bled into this cavernous

malformation.

(Right) Axial T2WI MR shows diffuse but asymmetrical medullary expansion & T2 hyperintensity =:I in a 7 year old This medullary astrocytoma did not

enhance.

(Left) Sagiltal T I C+ MR shows a lobulated, ventrally exophytic, moderately enhancing

mass arising (rom

the medulla of a child. The pons & upper spinal cord were not involved by Wmor. (Right) Axial TI C+ MR shows an irregular, peripherally enhancing mass It] with central necrosis involving the medulla in a 39 year old man. The patient had no symptoms of infection, & diffusion was not reduced

I 7 12

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a well-defined peripherally enhancing lesion with a thin regular rim II] involving the left dorsal medulla. The lesion was intermediate on T2WI. This patient also had lung nodules and epididymo-orchitis. Tuberculosis. (Right) Axial T2WI MR shows multiple small T2 hyperintense lesions scallered in the medulla. There was no associated

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secondary to hemangioblastoma. (Right) Axial T2WI MR shows enlargement & hyperintensity of the medullary olives R > L, in a patient with prior hemorrhage into a brainstem cavernoma.

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Common • Mega Cisterna Magna • Arachnoid Cyst Less Common • Neurocysticercosis • Dandy-Walker Continuum • Obstructive Hydrocephalus ("Trapped" or "Encysted" 4th Ventricle) • Pilocytic Astrocytoma • Hemangioblastoma • Epidermoid Cyst • Dermoid Cyst • Enlarged Perivascular Spaces Rare but Important • Congenital Vermian Hypoplasia • Ganglioglioma • Pleomorphic Xanthoastrocytoma • Neurenteric Cyst

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Is mass intra- or extra-axial? • lf extra-axial, cistern or 4th ventricle? o CSF cistern (mega cisterna magna, Dandy-Walker continuum, arachnoid cyst, epidermoid cyst) o 4th ventricle (encysted ventricle, neurocysticercosis, dermoid or epidermoid cyst, cystic neoplasm) • lf intra-axial, pons, vermis, or cerebellum? o Cerebellum (enlarged perivascular spaces, cystic neoplasm) o Vermis (cystic neoplasm, vermian hypoplasia) o Pons (cystic neoplasm> > enlarged perivascular spaces)

I 7 14

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Helpful Clues for Common Diagnoses • Mega Cisterna Magna o Enlarged posterior fossa CSF space o Normal vermis completely covers 4th ventricle (rules out Dandy-Walker malforma tion/varian t) o May show striking scalloping of skull (due to CSF pulsations) • Arachnoid Cyst o Sharply demarcated extra-axial cyst o Follows CSF attenuation/signal

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Suppresses on FLAIR,no DWI restriction Size varies from few millimeters to giant Often asymptomatic, found incidentally

Helpful Clues for Less Common Diagnoses • Neurocysticercosis o Best clue: Cyst with "dot" inside • ± Discrete eccentric scolex • Cyst slightly hyperintense to CSF o Cisterns> 4th ventricle • Dandy-Walker Continuum o DWC: Broad spectrum of cystic posterior fossa malformations o DW malformation: Large posterior fossa + large CSF cyst, normal 4th ventricle absent, lambdoid-torcular inversion o DW variant: Failure of "closure" of 4th ventricle, vermian hypoplasia o Includes persistent Blake pouch cyst, mega cisterna magna 02/3 have associated CNS &/or extracranial anomalies • Obstructive Hydrocephalus ("Trapped" or "Encysted" 4th Ventricle) o Due to obstructing lesions of 4th ventricle; all foramina must be involved (Magendie, Luschka, aqueduct) o May be from hemorrhage, infectious, inflammatory, or neoplastic causes o Ventricle enlarged but maintains basic shape o CSF intensity/attenuation • Pilocytic Astrocytoma o Cystic cerebellar mass with enhancing mural nodule o Cerebellum> vermis, 4th ventricle o Child> adult • Hemangioblastoma o Best diagnostic clue: Adult with intra-axial posterior fossa mass with cyst, enhancing mural nodule abutting pia o Size varies from tiny to several centimeters o 1-2% of primary intracranial tumors, 7-10% of posterior fossa tumors o May be associated with von Hippel-Lindau syndrome • Epidermoid Cyst o Congenital inclusion cyst o Lobulated, irregular, insinuating CSF-like mass with "fronds" o CerebeUopontine angle cistern> 4th ventricle

INFRATENTORIAl FLAIR usually doesn't completely null; restricts on DWI • Dermoid Cyst o Congenital inclusion cyst o Looks like fat • Use fat-suppression sequence to confirm • ± Rupture (fat droplets in cisterns, sulci, ventricles) • May cause chemical meningitis, extensive enhancement • Enlarged Perivascular Spaces o Pial-lined interstitial fluid-filled structures that accompany penetrating arteries but do not communicate directly with subarachnoid space o Cluster of variably sized intra-axial cysts o Off-midline (dentate nuclei) > midline (vermis, pons) o Follow CSF • Suppress completely on FLAIR • No restriction on DWI • No enhancement o "Leave me alone" lesion that should not be mistaken for serious disease o

Helpful Clues for Rare Diagnoses • Congenital Vermian Hypoplasia o Prototype = Joubert syndrome o Inherited hypoplasia or aplasia of vermis characterized by transient episodic hyperpnea, oculomotor abnormalities, ataxia, variable mental retardation

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"Molar tooth" brainstem; "bat wing" or "umbrella" shaped 4th ventricle; vermian remnant variable size o Midline anomalies common (holoprosencephaly, frontonasal dysplasia, facial clefting) • Ganglioglioma o Best diagnostic clue: Partially cystic, enhancing, cortically based mass in child/young adult o Cortical dysplasia commonly associated o Excellent prognosis if surgical resection complete o Malignant degeneration rare, approximately 5-10% (glial component) • Pleomorphic Xanthoastrocytoma o Supratentorial cortical mass with adjacent enhancing dural tail o Cyst and enhancing mural nodule typical o 98% supratentorial, rarely found in cerebellum o Despite circumscribed appearance, tumor often infiltrates • Neurenteric Cyst o Benign malformative endodermal C S cyst o Round/lobulated nonenhancing mass o Anterior to pontomedullary junction, slightly off-midline o Slightly/moderately hyperintense compared to CSF o

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Coronal TlWI MR demonstrates a sharply demarcated cyst in the midline posterior fossa just behind the vermis =:l. Contents followed CSF signal intensity on all

sequences.

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associated mild

obstructive hydrocephalus with transependymal CSF flow!:iJ. (Right) Sagillal T2WI MR demonstrates a markedly enlarged posterior fossa with cephalad rotation of superior vermian remnant ~ and a thinned inner table of the occipital

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Hemangioblastoma (Left) Sagillal T7 C+ MR shows a cystic-appearing midline mass II] with enhancing mural nodule B of hemangioblastoma. (Right) Axial T2WI MR demonstrates a typical MR appearance of a large epidermoid cyst as a mildly lobulated lesion that expands the 4th ventricle,

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I 7 16

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Cyst (Left) Sagittal T2WI MR shows hyperintense extra-axial ovoid mass 1m anterior

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DIFFERENTIAL DIAGNOSIS Common • Aging Brain, Normal • Encephalomalacia, NOS • Progressive on-Familial Adult Onset Cerebellar Degeneration o Chronic Vertebrobasilar Insufficiency o Alcoholic Encephalopathy o Phenytoin (Dilantin) Use, Chronic o Paraneoplastic Syndromes o Lithium Intoxication o Radiation and Chemotherapy o Hypothyroidism less Common • Cerebellitis, NOS Rare but Important • Multiple System Atrophy • Ataxia, Hereditary, NOS • Ataxia Telangiectasia • Cerebellar Atrophy, Hereditary, OS • Congenital Vermian Hypoplasia (Mimic)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Clinical history often more important in making diagnosis than imaging findings

I 7 18

Helpful Clues for Common Diagnoses • Aging Brain, Normal o ~ Brain volume (including cerebellum) with t age • Relative t CSF spaces • Selective atrophy of WM (not gray matter) predominates o "Successfully aging brain": Thin periventricular high signal rim without white matter hyperintensities o May find focal/confluent periventricular white matter hyperintensities • Encephalomalacia, NOS o All etiologies appear as CSF replacing destroyed parenchyma due to • Post-ischemic loss of tissue following parenchymal hypoxic cell death • Post-traumatic loss from parenchymal irreversible traumatic insult • Post-inflammatory loss by irreversibly injured tissue

• Progressive Non-Familial Adult Onset Cerebellar Degeneration o Chronic Vertebrobasilar Insufficiency • Vertebral artery stenosis, posterior circulation ischem ia • Posterior circulation ischemia of hemodynamic or embolic etiology • Atrophy w/sulcal enlargement; DWI dark o Alcoholic Encephalopathy • Primary (direct) effects of EtOH = neurotoxicity - cortical/cerebellar degeneration & atrophy • Best clue: Disproportionate superior vermian atrophy • F-18 FDG PET:Significant decrease in whole-brain metabolism o Phenytoin (Dilantin) Use, Chronic • Dilantin vs. seizures as cause of atrophy debated • Dilantin induces organic cerebellar damage & may interfere w/intestinal absorption of folate causing folate deficiency - cerebellar atrophy • Seizures can cause cerebellar atrophy as cerebellum is very sensitive to hypoxia cerebellar atrophy • Normal orientation & anisotropy of middle cerebellar peduncle & transverse pontine fibers o Paraneoplastic Syndromes • Remote neurological effect(s) of cancer, associated with extra-CNS tumors • Most common tumor: Small cell lung carcinoma • Manifestation of paraneoplastic encephalomyelitis associated w/cerebellar degeneration o Lithium Intoxication • Lithium is a neurotoxin with a particular affinity for the cerebellum • Atrophy of internal granule and Purkinje cell layers with dentate gliosis neuronal loss and spongiosis • Preceded by neuroleptic malignant syndrome o Radiation and Chemotherapy • Injury may be divided into acute, early delayed injury, late delayed injury • Diffuse white matter injury or necrosis • Radiation - induces cryptic vascular malformations; blood products

CEREBElLAR ATROPHY o

Hypothyroidism • Best diagnostic clue: Symmetrical pituitary enlargement reversible with thyroid hormone replacement therapy • May see generalized atrophy; alternatively focal cerebellar vermis or olivo pontocerebellar atrophy • • Cerebral perfusion & metabolism

Helpful Clues for Less Common Diagnoses • Cerebellitis, NOS o Rare inflammatory syndrome typically occurring as primary infectious, post-infectious, post-vaccination, or idiopathic disorder o Bilateral diffuse hemispheric abnormalities are most common (73%) o Often results in moderate to severe atrophy Helpful Clues for Rare Diagnoses • Multiple System Atrophy o Sporadic progressive neurodegenerative disorder of adult onset, unknown etiology o "Hot cross bun" sign: Cruciform pontine hyperintensity on T2WI o Impaired orientation/anisotropy of middle peduncle transverse pontine fibers • Ataxia, Hereditary, NOS o Example: Friedreich ataxia - cerebellar, spinal atrophy o Can be divided into autosomal dominant, autosomal recessive, X-linked, mitochondrial

Some etiologies (e.g., cerebrotendinous xanthomatosis) may have diffuse white matter T2 hyperintense lesions • Ataxia Telangiectasia o Progressive neurodegenerative disorder; onset in early childhood; 1 in 40,000 o Multisystem disease - cerebellar ataxia, oculomucocutaneous telangiectasias, & susceptibility to certain infections and neoplastic processes o Purkinje cell loss, atrophy of dentate nuclei, diffuse spongy degeneration, multiple foci of coagulative necrosis w/calcification in white matter • Cerebellar Atrophy, Hereditary, NOS o Middle-aged patients; severe superior vermian atrophy o Lesser involvement of cerebellar cortex o Severity of cerebellar atrophy correlates well with degree of ataxia • Congenital Vermian Hypoplasia (Mimic) o Prototype = Joubert syndrome o Inherited hypoplasia or aplasia of vermis characterized by transient episodic hyperpnea, oculomotor abnormalities, ataxia, variable mental retardation o "Molar tooth" brainstem; "bat wing" or "umbrella" shaped 4th ventricle; vermian remnant variable size o

Encephalomalacia,

Axial T2WI MR 3T MR obtained at age 76 if/ustrates generalized alfophy changes of prominent folial =:I and subarachnoid spaces 81. Also note slfiking ectasia of the basilar artery~

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(Lefl) Axial T1 WI MR reveals focal left cerebellar atrophy as a residua of closed head injury. (RighI) Sagittal T1 WI MR shows the classic finding of significant cerebellar atrophy with supratentorial parenchyma that appear normal.

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Paraneoplastic

Syndromes

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(Left) Axial GCT demonstrates a typical CT case with enhancement of cerebella, hemispheres bilaterally =:I. (Right) Sagittal TI WI MR of spontaneous olivopontocerebellar atrophy shows striking atrophy of the pons =:I,medulla 8l and cerebellar vermis Note the normal appearance of cerebral hemispheres .

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(Left) Sagittal T7 WI MR of hereditary olivopontocerebellar atrophy reveals striking vermian atrophy =:I as well as severe pontine atrophy with flattening 81. (Right) Axial T2WI MR reveals severe diffuse atrophy and gliosis =:I of cerebellar hemispheres in a patient with spinocerebellar ataxia.

(Left) Axial T7 WI MR demonstrates diffuse cerebellar =:I atrophy. Not shown are the normal cerebral hemispheres. (Right) Axial T2WI MR reveals hypoplasia of the

vermis, which could be mistaken for cerebellar atrophy =:I. Note the typical "molar tooth" shape g>J of the mesencephalon.

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CEREBELLAR

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Common • Cerebral Ischemia-Infarction, Acute • Hypertensive Intracranial Hemorrhage • Neoplasms o Medulloblastoma (P ET-MB) o Pilocytic Astrocytoma o Hemangioblastoma o Metastases, Parenchymal

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Less Common • Enlarged Perivascular Spaces • "Tumefactive" Demyelinating Disease o Multiple Sclerosis o ADEM • Abscess • Cerebellitis, NOS • Vascular Malformation, with/without Hemorrhage o Cavernous Malformation o Arteriovenous Malformation o Dural A-V Fistula Rare but Important • Tuberculosis • Glioblastoma Multiforme • Dysplastic Cerebellar Gangliocytoma • Oligodendroglioma • Ganglioglioma • Remote Cerebellar Hemorrhage

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Child vs. adult o Child: Neoplasm> infection, demyelinating disease o Adult: Ischemia, hypertensive hemorrhage > neoplasm

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Helpful Clues for Common Diagnoses • Cerebral Ischemia-Infarction, Acute o PICA distribution most common • DWI restriction w/correlating ADC map • Early cortical swelling • "Hemorrhagic transformation" in 15-45% • Hypertensive Intracranial Hemorrhage o Round/elliptical high density mass o 10% occur in pons, cerebellum • Medulloblastoma (PNET-MB) o 4th ventricle> cerebellum o Desmoplastic variant

• Pilocytic Astrocytoma o Best clue: Cystic mass + enhancing mural nodule o Childhood (not adult) tumor • Hemangioblastoma o Adult with intra-axial posterior fossa mass with cyst, enhancing mural nodule abutting pia o May be associated with von Hippel-Lindau syndrome • Metastases, Parenchymal o Intra-axial posterior fossa mass in middle-aged/older adult? Think metastasis! o Can be solitary but look for other lesions Helpful Clues for Less Common Diagnoses • Enlarged Perivascular Spaces o Fluid-filled spaces that look like CSF, surround/accompany penetrating arteries o No diffusion; may have FLAIR hyperintense parenchymal rim • Multiple Sclerosis o Fulminant acute plaque or conglomeration of acute plaques forming mass lesion(s) o May display ring enhancement simulating tumor or abscess o Most common disabling CNS disease of young adults; 1:1000 in developed countries • ADEM o Lesions 10-14 days following infection/vaccina tion o Large flocculent FLAIRhyperintensity but with less mass effect than that expected o Punctate, ring, incomplete ring, peripheral enhancement • Abscess o Especially in children o Ring-enhancing lesion • High signal on DWl, low ADC • T2 hypointense rim with surrounding edema o Central necrotic area may show presence of acetate, lactate, alanine, succinate, pyruvate, amino acids on MRS • Cere belli tis, NOS o Typically occurs as a primary infectious, post-infectious, post-vaccination, or idiopathic disorder o Variable enhancement - none to intense;

meningeal enhancement can be seen o

Abnormal T2 hyperintensity

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swelling

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Bilateral diffuse hemispheric abnormalities are most common (73%) • Cavernous Malformation o "Popcorn ball" appearance with complete hypointense hemosiderin rim on T2WI MR o ECT: 40-60% Ca++ • Arteriovenous Malformation o "Bag of black worms" (flow voids) on MR with minimal/no mass effect o Flow-related aneurysm on feeding artery 10-15%; intranidal "aneurysm" > 50% • Dural A-V Fistula o Best imaging tool: DSA with superselective catheterization of feeders o Dural AVFinvolving the region of the foramen magnum, tentorium, torcula Herophili, or posterior fossa veins (e.g., inferior vermian vein) may affect cerebellum o Most often presents with hemorrhage Helpful Clues for Rare Diagnoses • Tuberculosis o CECT: "Target sign" -+ central Ca++ or enhancement surrounded by enhancing rim o T1 C+: Solid homogeneous to rim enhancement; ± central necrosis o MRS: Prominent lipid, lactate but no amino acid resonances • Glioblastoma Multiforme o Thick irregular enhancing rind of neoplastic tissue surrounding necrotic core

Cerebral

Ischemia-Infarction,

Acute

Axial T2WI MR demons!rales a lypical case of PICA acute infarction as hyperintensity associated with swelling in lhe righl cerebellar hemisphere SI and laleral medulla =:I_

Characterized by necrosis and neovascularity o Viable tumor extends far beyond signal abnormali ties Dysplastic Cerebellar Gangliocytoma o Widened cerebellar folia with a striated appearance on MR o Thinning of skull may be apparent o a.k.a., Lhermitte-Duclos disease, associated with Cowden syndrome Oligodendroglioma o Partially Ca++ subcortical/cortical mass in middle-aged adult o Majority calcify -+ nodular or clumped Ca++ (70-90%) o May expand, remodel, erode calvarium Ganglioglioma o Partially cystic, enhancing, cortically based mass in child or young adult o Ca++ common -+ 35-50% o Cortical dysplasia is commonly associated Remote Cerebellar Hemorrhage o Occurs after supratentorial craniotomy o Superior cerebellar folia • Bilateral (33%) • Contralateral to side of surgery (29%) • Ipsilateral (22%); isolated vermian (9%) o

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Hemorrhage

Axial NEeT shows a large high densily mass in !he lefl cerebellar hemisphere =:I wilh some adjacenl areas of s/ighdy lesser increased auenualion indica ling aclive

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Medulloblastoma

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(Left) Axial T7 C+ MR shows a poorly defined mass with components in vermis, right cerebellar hemisphere with irregular pattern of enhancemenl Note temporal horn enlargement from obstructive hydrocephalus 81. (Right) Axial T7 C+ MR shows classic cystic cerebellar pilocylic astrocytoma with

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robustly enhancing mural nodule 81.

Hemangioblastoma

Metastases,

Parenchymal

(Left) Axial T7 C+ FS MR demonstrates a typical MR appearance of cerebellar hemangioblastoma with both an avidly enhancing solid nodule and cystic component 81. (Right) Axial T7 C+ MR demonstrates left cerebellar, temporal tip intensely enhancing masses T7 and T2 shortening (not shown) demonstrated hemorrhage. Pathology confirmed metastases from renal cell carcinoma.

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Metastases, Parenchymal (Left) Axial T7 C+ MR shows solitary metastasis with thin rim enhancement no

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adenocarcinoma metastases of unknown origin. (Right) Axial T7 C+ MR demonstrates a variably sized cluster of non enhancing CSF-like cysts in left dentate nucleus, cerebellum P.>J Note mild mass effect on 4th ventricle

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Enlarged Perivascular Spaces

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(Left) Axial T2WI MR shows variant case of MS with large demyelinating plaques in pons ~ and the right cerebellar hemisphere A mild mass effect is present. fRight) Axial FLAIR MR demonstrates hyperintense flocculent ADEM lesions of the cerebellum.

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Abscess

Abscess

fLeft) Axial T1 C+ MR shows a thick rim of enhancement I:] surrounding a nonenhancing central core. At surgery, a well-developed cerebral abscess with thick collagenous capsule was drained. fRight) MRS of abscess with TR2000/TE288 shows a large lactate peak resonating at 1.3 ppm a large acetate peak at 2 ppm El a smaller alanine peak at 1.5 ppm and a peak at 0.9 ppm ~ representing cytosolic amino acids

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Cerebellitis,

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Cavernous Malformation (Left) Axial T2WI MR shows a typical case 01 cerebellitis as hyperinlensity and mild swelling of bilateral cerebellar hemispheres ~. Post-contrast images showed marked associated enhancement. (Right) Axial T2WI FS MR demonstrates

the classic "popcorn

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appearance of a cavernous malformation in the upper vermis associated with a developmental venous anomaly (not shown). Note T2 heterogeneity of interstices with hypoinlense hemosiderin rim.

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CEREBElLAR

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Cavernous Malformation (Left) Axial SWI in patient with multiple cavernous malformation syndrome

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susceptibility-weighted sequence by revealing innumerable cavernous malformations, many of which were not apparent on CRE or T2 imaging. (Right) Axial NECT in a young woman with severe headache and collapse shows cerebellar hemorrhage with upward herniation causing obstructive hydrocephalus.

Arteriovenous

Malformation

Dural A-V Fistula

(Left) Anteroposterior CTA in the same patient with 3D reconstruction demonstrates a large right cerebellar AVM with a prominent draining vein 8:1. (RighI) Sagittal T2WI MR shows prominent flow voids impacting the inferior vermis Ell multiple serpentine flow voids adjacent to the cord &, cord hyperintensity with mild fusiform cord expansion from C7 to C4~.

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phase shows a dural fistula IG>lsupplied by posterior meningeal branches ffi (Right) Axial T7 C+ MR reveals irregular rim enhancement around a tuberculoma with associated leptomeningeal enhancement around the pons and 3rd cranial nerves

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Tuberculosis

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Glioblastoma Multiforme (Left) Axial T7 C+ FS MR reveals CBM CSF spread as a deFined vermian enhancing nodule as well as an enhancing coaling along numerous subarachnoid space structures~. (Right) Axial T2WI MR shows a large nonenhancing mass involving the left cerebellar hemisphere The most characteristic imaging feature is preservation of the cerebellar folia pattern or "stria/ed cerebellum ", typical

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(Left) Axial T1 C+ MR shows variant case of 4/h ventricular oligodendroglioma that mimics ependymoma. Images reveal heterogeneous enhancement of mass Ea involving 4th ventricle foramen of Luschka. Intraventricular oligodendrogliomas are very rare, occurring in 1 to 10% of cases. (Right) Axial T7 C+ MR at 0.6 T reveals a cyst-like lesion that demonstrates thick ring-like enhancement and significant local mass effect.

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Remote Cerebellar Hemorrhage

Remote Cerebellar Hemorrhage (Left) Axial NECT obtained

immediate status post supratentorial

craniotomy

reveals spontaneous superficial cerebellar hyperdense hemorrhage

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following the cerebellar folia is the most typical pattern observed. (Right) Axial T2* CRE MR performed 2 days following craniotomy shows to better advantage a hemorrhage in a superficial configuration lit] in a linear pattern of blood products, which appears to follow the cerebellar folia.

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VERMIS MASS

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DIAGNOSIS

Common • Medulloblastoma (PNET-MB) • Pilocytic Astrocytoma Less Common • Metastasis • Hemangioblastoma Rare but Important • Dural A-V Fistula • Arteriovenous Malformation • Cavernous Malformation • Cerebellitis • Atypical Teratoid-Rhabdoid Tumor • Dermoid Cyst • Glioblastoma Multiforme • Ganglioglioma • Dysplastic Cerebellar Gangliocytoma • Rhombencephalosynapsis (Mimic)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Patient age o Child: PNET-MB, pilocytic astrocytoma (PA), ATRTmost common o Adult: Metastasis, hemangioblastoma most common • Does mass originate in vermis or 4th ventricle (V)? o Vermis: PA, metastasis, hemangioblastoma, cerebellitis, ATRT o 4th ventricle: PNET-MB (from superior medullary velum), ATRT

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Helpful Clues for Common Diagnoses • Medulloblastoma (PNET-MB) o 30-40% of childhood infratentorial tumors o Round, hyperdense 4th ventricle mass • Arises from 4th ventricle roof • Posteroinferior spread into cisterna magna • Distinguishes P ET-MBfrom ependymoma (arises from floor, extrudes laterally) • Look for early subarachnoid spread o Lateral cerebellar hemisphere location • Desmoplastic variant • More common in older children, adults • Pilocytic Astrocytoma o Cystic mass with enhancing mural nodule

Hemispheres> vermis o Ca++ 20%, hemorrhage rare o

Helpful Clues for Less Common Diagnoses • Metastasis o ALWAYSinclude metastasis in differential diagnosis of posterior fossa parenchymal mass in adult! • Seen in 25% of cancer patients at autopsy • Location approximately 80% hemispheres, 15% vermis, 5% pons/midbrain o Metastases have rounded configuration • Usually displace rather than infiltrate tissue • Virtually 100% enhance • Variable edema o Can be hematogenous or originate from leptomeningeal carcinomatosis • Hemangioblastoma o Adult with intra-axial posterior fossa mass = metastasis vs. hemangioblastoma • Classic imaging of hemangioblastoma = cyst + enhancing mural nodule abutting pia • Solid mass ± hemorrhage less common • Size varies (tiny to several centimeters) o Only 1-2% of 1 intracranial tumors but 7-10% of posterior fossa tumors • 80% cerebellar hemispheres • 15% vermis, 5% other (medulla, 4th V) o ± von Hippel-Lindau syndrome • Hemangioblastomas in VHL typically don't develop until young adulthood, middle age • Rare in children 0

Helpful Clues for Rare Diagnoses • Dural A-V Fistula o 10-15% of all cerebrovascular malformations o Dural AVF involving foramen magnum, tentorium, torcula Herophili, or posterior fossa veins (e.g., inferior vermian vein) may affect vermis o May be occult, cause tinnitus o Can present with hemorrhage o Rare: Dementia • Arteriovenous Malformation o "Bag of black worms" on MR with minimal/no mass effect unless hemorrhage o

Posterior fossa < hemispheres

VERMIS MASS o Headache, hemorrhage in 50% • Cavernous Malformation o Benign vascular hamartoma with masses of immature blood vessels ("caverns"), intralesional hemorrhages, no neural tissue o Seizure 50%, neurologic deficit 25%, asymptomatic 20% o NECT: 40-60% Ca++

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• Most common pattern = "popcorn ball" with hypointense rim • May present initially with large hematoma o Can be familial, multiple (multiple cavernous malformation syndrome) • Do T2* scan (GRE or SWI) in all cases of spontaneous, "unexplained" intracranial hemorrhage! • Cerebellitis o Rare inflammatory syndrome • Can be primary infectious, post-infectious, post-vaccination, or idiopathic o Imaging often nonspecific o

MR > > CT

• Bilateral hemispheric involvement (75%) • T2 hyperintensity • Variable enhancement (none to intense) • Atypical Teratoid-Rhabdoid Tumor o Infant/young child o 50% infra tentorial o Off-midline> vermis o Mass often large, heterogeneous o Can mimic PNET-MB

Axial NECT shows a rounded hyperdense mass ~ within expanded 4th ventricfe 81, Note enlarged temporal horns indicative of obstructive hydrocephalus,

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• Dermoid Cyst o Rare: < 0.5% of 1 intracranial tumors o Fat appearance: Use fat-suppressed sequence to confirm o With rupture find fat droplets in cisterns, sulci, ventricles w/extensive enhancement possible from chemical meningitis • Glioblastoma MuItiforme o Rapidly enlarging tumor with necrosis, neovascularity o Peak 45-70 years but may occur at any age o Cerebellum uncommon primary site o 95% have thick, irregular enhancing rind of neoplastic tissue surrounding necrotic core • Ganglioglioma o Well-differentiated, slowly growing neuroepithelial tumor composed of neoplastic ganglion cells & glial cells o Partially cystic, enhancing, cortically based mass in child or young adult o Hemispheres> > cerebellum o Ca++ common (35-50%) • Dysplastic Cerebellar Gangliocytoma o Also known as Lhermitte-Duclos disease o Thick cerebellar folia with "striated" appearance on MR o Mass effect may be striking o Associated with Cowden syndrome • Rhombencephalosynapsis (Mimic) o Single lobed cerebellum w/transverse folia o Dentate nuclei, superior cerebellar peduncles fused o Vermis absent 0

Sagiual T1 C+ MR shows a midline cystic mass ~ with solid enhancing nodule E2 in vermis. Note compression, anterior displacement of 4th ventricle

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Pathology confirmed adenocarcinoma of unknown primary. (Right) Sagittal T1 C+ MR in an adult with headache, papilledema demonstrates cystic mass involving vermis, with a strongly enhancing mural nodule SlI. Note compression, anterior displacement of 4th ventricle

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Arteriovenous

Malformation

(Left) Sagiltal T2WI MR shows prominent flow voids within the posterior fossa m

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hyperintensity and mild fusiform cord expansion from C1 to C4 !:J. (Right) Axial CECT show an enlarged feeding artery in the CPA cistern

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Cavernous (Leh) Axial T2WI FS MR demonstrates a mixed signal intensity lesion or the vermis It] with a "popcorn"

appearance and classic peripheral hemosiderin staining. (Right) Axial CECT shows diffuse enhancement of the cerebellum ~ in a young patient with cerebellitis.

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Malformation

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Dermoid Cyst (Left) Sagittal T1 C+ MR in lhis 2 year old shows a

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(Left) Axial T2WI MR shows a classic appearance for dysplaslic cerebellar gangliocylOma as a hyperintense mass with dislinct strialed morphology

D11. The vermis is a less common site than the cerebellar hemisphere. (Right) Axial T2WI MR shows fusion of cerebellar

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Common • Tonsillar Ectopia • Chiari 1 • Herniation Syndromes,

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• Sagittal phase contrast MR best Low torcular, effaced posterior fossa cisterns o Folia orientation runs more vertically o Look for syrinx, CVJ/skull base anomalies • Herniation Syndromes, Intracranial a Tonsils impacted inferiorly into FM a Posterior fossa CSF cisterns effaced a Clinically associated with decreased mental status or obtundation

DIFFERENTIAL DIAGNOSIS

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ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Cerebellar tonsils may normally lie up to 5 mm below foramen magnum (FM) • Normal rounded tonsillar shape/configuration more important than precise measurement • Normal folia course horizontally, not vertically • Chiari 2 is not in differential diagnosis (herniated tissue is nodulus of vermis, not tonsils!) Helpful Clues for Common Diagnoses • Tonsillar Ectopia a Zero to 4.8 mm below foramen magnum a Avoid terms "Chiari A" or "Chiari 1/2" • Chiari 1 a Pointed "peg-like" cerebellar tonsils> 5 mm below foramen magnum o Absent CSF space/flow behind tonsil

Helpful Clues for less Common Diagnoses • Intracranial Hypotension a Can be spontaneous or acquired o "Slumping" midbrain, flattened pons, optic chiasm draped over dorsum sellae a Diffusely enhancing thickened dura ± SOH • Basilar Invagination (Mimic) a A mimic -+ tonsils are normal a Primary often associated with bony malformations such as occipitalization of the atlas or Klippel-Feil; often familial a Secondary from acquired bone diseases that cause "softening" & skull base flattening, such as osteogenesis imperfecta, osteomalacia, Paget Helpful Clues for Rare Diagnoses • Brain Death a Gyral swelling with complete central brain herniation -+ tonsils pushed downward a No intracranial vascular flow a Clinical diagnosis, legal criteria varies

Tonsillar Ectopia

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Foreshortened clivus, norma/4th ventricle.

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(Left) Sagittal CINE phase contrast MR demonstrates CSF flow as black on this diastolic image Lack of posterior CSF flow E!:J is

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Basilar Invagination (Mimic) (Left) Sagittal T1 WI MR shows tonsillar descent obliteration of suprasellar cistern as well as a sagging and fat midbrain. (Right) Sagittal T1 WI MR

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DIFFERENTIAL DIAGNOSIS Common • Mega Cisterna Magna • Arachnoid Cyst • Dandy-Walker Continuum • Pilocytic Astrocytoma • Encephaloceles • Obstructive Hydrocephalus less Common • Epidermoid Cyst • Dermoid Cyst • Neuroglial Cyst • Ependymal Cyst • Hemangioblastoma • Schwannoma (Cystic) • Abscess • Enlarged Perivascular Spaces Rare but Important • Syringobulbia • Neurenteric Cyst • Atypical Teratoid-Rhabdoid Tumor • Metastases, Intracranial, Other • Neurocysticercosis • Chordoma • Congenital Muscular Dystrophy

ESSENTIAL INFORMATION

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Key Differential Diagnosis Issues • Cystic-appearing lesion exactly like CSF on all sequences? o Mega cisterna magna (MCM), arachnoid cyst (AC), Dandy-Walker Continuum (DW) o Trapped 4th ventricle, enlarged perivascular spaces (t PVSs), neuroglial or ependymal cyst • Cystic-appearing lesion not exactly like CSF? o Congenital inclusion cyst (dermoid, epidermoid, neurenteric cysts) o Infection such as abscess, neurocysticercosis (NCC) o eoplasm (pilocytic astrocytoma, hemangioblastoma, metastasis, chordoma) • Is cyst intra- or extra-axial? • Intra-axial o Trapped fourth ventricle (4th V), t PVSs o Neoplasm (e.g., pilocytic astrocytoma), infection (abscess, NCC) o Inclusion cyst in 4th V (epidermoid)

• Extra-axial o MCM, AC, DW, neurenteric cyst, NCC, neoplasm (schwannoma) • DWI, Tl C+ scans helpful additions Helpful Clues for Common Diagnoses • Mega Cisterna Magna o Communicates freely with all CSF spaces o Normal tegmento-vermian angle « 5-10°) • Arachnoid Cyst o Mass effect on vermis o ± Hydrocephalus o Use FLAIR,DWI to exclude epidermoid • Dandy-Walker Continuum o "Classic" Dandy-Walker malformation • Cystic dilatation 4th V ~ t posterior fossa (PF), torcular-lambdoid inversion • Hypoplastic vermis • Vermian remnant rotated anterosuperiorly over cyst o Blake pouch cyst (BPC) • Embryonic BPC doesn't regress • Enlarged PF, 4th V open inferiorly • Vermis anatomically complete • Pilocytic Astrocytoma o Cystic cerebellar mass o Enhancing mural nodule • Encephaloceles o Isolated encephalocele: Lacks Chiari 2 o Chiari 3 = Chiari 2 PLUS • Occipital or cervical encephalocele containing cerebellum o Syndromic occipital encephalocele • Klippel-Feil, Meckel-Gruber, etc. • Obstructive Hydrocephalus o Outlets obstructed4th ventricle t t o Maintains "kidney bean" configuration o 3rd V, shunted lateral ventricles small Helpful Clues for less Common Diagnoses • Epidermoid Cyst o Cerebellopontine angle> 4th V > diploic o Frond-like, cystic (CSF-like) o Doesn't suppress completely on FLAIR o Restricts on DWI • Dermoid Cyst o Midline "fatty" mass • "Droplets" in CSF if ruptured • Look for dermal sinus, midline vertebral/skull base anomalies • Neuroglial Cyst o

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• Ependymal Cyst o CSF-like o Intra- > para ventricular • Hemangioblastoma o Posterior fossa mass with cyst, enhancing mural nodule that abuts pia o ± Arterial feeders, flow-voids o Look for markers of von Hippel-Lindau (VHL) • Visceral cysts, renal clear cell carcinoma o Adult> > older teen (unless VHL) • Check family history! • Schwannoma (Cystic) o Vestibular schwannoma (VS) looks like "ice cream on cone" o Cysts can be intratumoral or VS-associated (arachnoid) o Solid component enhances • Abscess o T2 hypointense rim with surrounding edema o Ring-enhancing o DWI hyperintense, ADC hypointense • Enlarged Perivascular Spaces o CSF-like, nonenhancing, non restricting o Most common PF site = dentate nuclei o Less common = cerebellum, pons Helpful Clues for Rare Diagnoses • Syringobulbia o May occur with either Chiari 1 or 2 o Cervicaljholocord syrinx common o May extend further into brain (syringocephaly)

• Neurenteric Cyst o Slightly hyperintense extra-axial cystic mass, nonenhancing o Anterior pontomedullary, CPA cisterns • Atypical Teratoid-Rhabdoid Tumor o 50% infratentorial (usually off-midline) o Intratumoral cysts, hemorrhage common o Gross macrocysts less common • Metastases, Intracranial, Other o Myriad of non enhancing interfoliate cysts • Low or high grade brain or spine primary • Also reported with breast primary o Choroid plexus papilloma cysts can be entirely extra-axial, nonenhancing • Neurocysticercosis o Cyst with "dot" (scolex) inside o Subarachnoid spaces, sulcal depths most common o Intraventricular cysts often isolated • 4th ventricle most common • Chordoma o High signal T2 o Moderate to marked enhancement unless necrotic, mucinous o High attenuation foci (CT) may be occult onMR • Congenital Muscular Dystrophy o Best diagnostic clues • Severely "floppy" infant • Z-shaped or cleft pons • Multiple small CSF-like cerebellar cysts (may be PVSsor trapped CSF from overmigration of neurons)

Arachnoid

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Cyst

I Sagittal T1WI MR shows a mega cisterna magna 81. The tentorium is normally located, and the posterior fossa is mildly prominent. There is no mass effect upon the vermis.

Sagittal T1WI MR shows a reuocerebellar arachnoid cyst. There is enlargement of the posterior fossa, elevation of the lent, and mild compression of Ule

7

vermis.

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Dandy-Walker

Continuum

Dandy-Walker

Continuum

(Left) Sagittal T1 WI MR shows typical enlarged posterior rotation

fossa, upward of the small vermian

remnant,

elevation

tentorium,

of the

and mass effect

upon the brainslem

in

"classic" Dandy-Walker malformation. (Right) Sagillal T2WI MR shows enlargement

4th ventricle communicates enlarged

of the inferior

which with an

cisterna magna

in

this infant with a Blake pouch cyst.

(Left) Sagillal T1 C+ MR shows a large cystic neoplasm of the vermis. There is compression of the brainstem and 4th ventricle PJ::l by the rim-enhancing mass. Nodular thickening E!:I is present in the caudal aspect of this cerebellar "juvenile" pifocylic astrocytoma UPA). (Right) Axial T2WI MR shows very high signal of the cystic component

The solid rim of

the JPA is thick Ii8 and brighter than gray mailer.

Encephaloceles (Left) Sagillal PO FSf MR shows a classic Chiar; 3 malformation

with extension

of infratenloriallissue and also the venous system 0::>] into the large occipital encephalocele. (Right) Axial T2WI MR shows cerebellar tissue ~ protruding into the encephalocele sac.

I 7 36

Encephaloceles

"CYSTIC-APPEARING"

POSTERIOR

CIl

FOSSA LESION

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(Left) Sagittal T2WI MR shows a dilated trapped 4th ventricle in a child with a history of hydrocephalus due to intraventricular hemorrhage as a premature inFant. Note the corpus callosum & thinned due to perivenlricular

leukoma/acia.

The 3rd ventricle, unlike the 4th ventricle,

is normal

in

size. (Rig"') Sagittal T2WI MR in a child with mild ventriculomegalyand holocord syrinx 81 demonstrates extension of the syrinx into the medulla

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(Left) Axial T1 C+ MR shows a small, CSF-like cyst 81 deForming the right cerebellopontine angle. (Right) Axial OWl MR shows diffusion restriction of the lobular mass Ell confirming the presence of an epidermoid tumor. An arachnoid cyst would not restrict.

Dermoid Cyst

Dermoid Cyst (Left) Sagillal T2WI MR shows a cystic structure [? indenting

the inferior

vermis.

Note also the segmentation anomalies of C2 81 and the midline sagillal cleFting of the upper cervical cord in this child with Klippe/-Feil anomaly. (Right) Axial OWl MR in the same child shows diffusion restriction 81. The dermoid was subjacent to a dermal sinus.

I 7 37

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POSTERIOR

FOSSA lESION

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Neuroglial

Cyst

(Left) Sagittal T2WI MR shows a large CSF intensity cyst filling the pineal/quadrigeminal

region.

With the rim of brain parenchyma stretched around the mass, it is intra-axial and most likely represents a neuroglial cyst (Right) Sagittal T1 C+ MR shows a small, well-delineated CSF-filled cyst SI in the inferior 4th ventricle. Cyst displaces the enhancing choroid plexus IJ:11 which is draped over it.

Hemangioblastoma (Left) Sagittal T2WI MR in a teenager with von Hippel-Lindau shows a large tumor-associated cyst in the medulla. There are flow voids within the adjacent soft tissue mass. Typical upper cervical cord edema SI is present. (Right) Coronal T1 C+ MR in the

=

e::l

same patient shows enhancement of the soft tissue nodule This is classic hemangioblastoma with tumor nodule, cyst wall

e::l.

composed

of nonneoplastic

tissue (compressed cerebellum).

Schwannoma (Left) Axial T1 C+ MR shows a large cyst is associated with an lAC/CPA mass. Note the classic "ice cream on a cone" Et:I enhancement, typical for vestibulocochlear schwannoma. Associated cysts are uncommon. (Righi) Axial T2WI MR shows typical low signal intensity rim of the abscess cavity IaI surrounded by edema. There is mastoiditis the underlying etiology of the abscess in this child.

a

I 7 38

(Cystic)

Abscess

"CYSTIC-APPEARING"

POSTERIOR

FOSSA lESION III

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Enlarged Perivascular Spaces

Neurenteric

Cyst

III

(Lefl) Axial T2WI MR shows clusters of multiple tiny hyperintense cystic areas in dentate nuclei, basal ganglia E1 The cystic" lesions" are clusters of enlarged

::::J

perivascular spaces,

Q)

constituting

OJ ...••

the condition

called Uetat crib/e'l (French for cribriform state). It is considered a normal variant and typically does not cause symptoms. (RighI) Sagittal T2WI MR shows a high signal cystic mass 81 that indents the anterior aspect of the medulla.

Metastases,

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Intracranial, Other (Left) Sagittal TI C+ MR shows a superior 4th ventricle mass E1 and a large rim-enhancing cyst. Cysts are more common with posterior fossa atypical teratoid-rhabdoid tumor than PNET-Mf3. (Rig"') Axial T2WI MR shows extensive inlerfoliale cystic metastases associated with high grade spinal astrocytoma.

=

Neurocysticercosis

Congenital Muscular Dystrophy (Lefl) Sagittal TI WI MR shows a cyst with a nodule inside the fourth ventricle

Ncurocysticcrcosis

cyst

was confirmed

pathologically. The pro£oscolex is the viable

larva within the smooth, thin-walled cyst. (RighI) Axial T2WI MR shows multiple small cystic lesions in the dysplastic cerebellum The pons is hypoplastic with dorsal clefting ~ Hypomyelination of the temporal lobes is present 81.

=.

I 7 39

ro

POSTERIOR

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FOSSA NEOPLASM,

ADULT

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DIFFERENTIAL DIAGNOSIS Common • Vestibular Schwannoma Less Common • Meningioma, CPA-lAC • Metastases, CPA-lAC • Metastasis, Parenchymal • Hemangioblastoma • Other Schwannomas o Schwannoma, Trigeminal, Intracranial o Schwannoma, Facial Nerve, CPA-lAC o Schwan noma, Jugular Foramen o Schwannoma, Hypoglossal Nerve • Subependymoma • Choroid Plexus Papilloma Rare but Important • Astrocytomas o Glioblastoma Multiforme (GBM) o Anaplastic Astrocytoma o Diffuse Astrocytoma, Low Grade o Pilocytic Astrocytoma • Paraganglioma, Glomus JuguJare • Dysplastic Cerebellar Gangliocytoma (Lhermitte-Duclos) • Medulloblastoma (Desmoplastic Variant) • Hemangiopericytoma • Lymphoma • Ecchordosis Physaliphora • Rosette-Forming Glioneuronal Tumor of the Fourth Ventricle • Cerebellar Liponeurocytoma

ESSENTIAL INFORMATION

I 7 40

o

• Overall most common by far is metastasis • Hemangioblastoma most common primary • Astrocytomas, most common supratentorial tumors, rare in PF Fourth ventricle • Subependymoma > choroid plexus papilloma (CPP) • Subependymoma in inferior fourth ventricle (obex) • CPP in body/lateral recess, CPA

Helpful Clues for Common Diagnoses • Vestibular Schwannoma o By far most common adult posterior fossa neoplasm; all others less common or rare! o 90% of all CPA-lAC masses o Looks like "ice cream on cone" (CPA-lAC) o Enhances strongly o ± Intra- or extra tumoral cysts Helpful Clues for Less Common Diagnoses • Meningioma, CPA-lAC o "Mushroom-shaped" mass caps lAC o Flat base towards dural surface o ± Hyperostosis, dural tail sign o 25% show lAC involvement! • Metastases, CPA-lAC o CPA metastases can arise in 4 locations • Dura-arachnoid • Cranial nerves (7, 8 most common) • Flocculus • Choroid plexus (foramen of Luschka) o Irregular, invasive margins • Metastasis, Parenchymal o Second only to VS as adult PF neoplasm o Most common parenchymal PF tumor o Rarely may be only brain metastasis! • Hemangioblastoma o 95% posterior fossa (hemispheres> > vermis> brainstem, 4th ventricle) o < 50% of patients have VHL (look for multiple lesions, visceral cysts, etc.) o Imaging • 60% non enhancing cyst + strongly enhancing mural nodule abutting pia • 40% solid, ± blood products • Other Schwannomas o Trigeminal (CN5) schwan noma • Upper CPA mass • Look for "dumbbell" shape (CPA + Meckel cave components)

POSTERIOR

FOSSA NEOPLASM,

ADULT

,...

C/l

c:

Facial nerve (CN?) schwannoma • CPA-lAC mass with "labyrinthine tail" • Look for labyrinthine segment tumor (if absent, can't distinguish from VS) o Jugular foramen OF) schwannoma • Enhancing mass arising from JF • Smooth remodeling of bony margins • Projects cephalad into CPA cistern o Hypog]ossal (CN12) schwannoma (rare) • Smooth remodeling of hypoglossal canal • Look for ipsilateral tongue atrophy • Subependymoma o Middle-aged/elderly adult o Most small, asymptomatic o T2 hyperintense lobulated mass in inferior 4th ventricle (obex) o May have cysts, Ca++; hemorrhage rare • Choroid Plexus Papilloma 040% of CPPs occur in 4th V, CPA o Most common in adults o Cauliflower or frond-like excrescences o Intense, relatively uniform enhancement o

Helpful Clues for Rare Diagnoses • Astrocytomas o Glioblastoma Multiforme (GBM) • Infratentorial GBMs rare • Typically necrotic, ring-enhancing o Anaplastic Astrocytoma • Also rare; infiltrative, variable enhancement o Diffuse Astrocytoma (Low Grade) • Young adults o Pilocytic Astrocytoma

Vestibular

•

•

•

•

• Rare in adults Paraganglioma, Glomus jugulare o Superolateral into middle ear> > CPA o Look for "sa]t and pepper" "flow voids" o Erosive, destructive, infiltrative Dysplastic Cerebellar Gangliocytoma (Lhermitte-Duclos) o Widened, irregular cerebellar folia with layered/laminated "striped" appearance o May cause significant mass effect o Typically doesn't enhance (rarely may) Medullob]astoma (Desmoplastic Variant) o "Desmoplastic" variant more common in 2nd, 3rd decades • Off-midline (lateral cerebellar hemisphere) location • Enhances; CSF spread less common Ecchordosis Physaliphora o Small, gelatinous tissue mass considered ectopic notochordal remnant o Midline of craniospinal axis from dorsum sellae to sacrococcygeal region o Clivaljretrocliva] in posterior fossa o Found in 2% of autopsies o Typically asymptomatic o Hypointense on Tl WI, hyperintense on T2WI; nonenhancing o May involve/erode clivus, ± stalk-like connection to mass

III

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Schwannoma

Axial T1 C+ MR shows a large extra-axial enhancing mass =:I displacing/rotaUng !he pons. Note !he extension into lAC ~ and a cenfJal intratumoraf cyst

Axial T1 C+ MR shows a large, mushroom-shaped, enhancing mass in the right CPA cistern. The mass has a broad base towards !he dural surface. Note dural tail sign ES:I or reactive meningeal thickening in lAC

I 7 41

POSTERIOR

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FOSSA NEOPLASM,

ADULT

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Metastases, CPA-lAC

Metastasis, Parenchymal

(Leh) Axial T2WI MR in a female with breast carcinoma shows a lobulated extra-axial mass in the right flocculus ~ with associated parenchymal edema ~. Normal flocculus on left 81. (Right) Coronal T1 C+ MR shows enhancing nodule ~ with rim-enhancing cyst [;8 This was the only lesion in a patient with known systemic cancer. Lesion resembles a hemangioblastoma (HeB), but the cyst wall in most HCBs is nonneoplastic (nonenhancing compressed cerebellum).

Hemangioblastoma

Schwan noma, Jugular Foramen

(Left) Axial T1 C+ FS MR

shows classic

=

hemangioblastoma with solid tumor nodule abutting pial surface of cerebellum. Associated cyst 81 does not enhance because wall is

compressed,

nonneoplastic

cerebellum. (Right) Axial T1 C+ MR shows large, solid, intensely enhancing,

extra-axial mass extending into enlarged, smoothly remodeled

jugular

foramen

1m. Intratumoral cysts, not present in this case, are common in posterior fossa schwannomas.

Choroid (Left) Sagittal T2WI MR shows a small, mildly hyperintense mass m in the inferior

fourth ventricle,

found incidentally in this 43 year old male with headache, trigeminal neuralgia. No hydrocephalus was idenulied. Presumed subependymoma. (Right) Coronal T1 C+ MR in a 43 year old female with headaches shows a "speckled" or "bubbly" strongly but heterogeneously enhancing

I 7 42

ventricle

mass in the fourth

=

with extension

into the lateral recess 81.

Plexus Papilloma

POSTERIOR

FOSSA NEOPLASM,

Diffuse Astrocytoma,

ADULT

low Grade (Left) Axial T7 C+ MR in an older teenager w/nausea &

vomiting shows inhomogeneously enhancing vermian mass I:) with cystic, solid components. Pre-operative diagnosis was malignant astrocytoma. WHO wade If tumo, was found at biopsy, possibly secondary to sampling as this tumor looks nasty! (Right) Sagittal T2WI MR in 25 year old lema Ie with lower cranial nerve palsies shows dorsally exophytic pontomedullary mass =::a. Biopsy-proven WI 10 grade If astrocytoma.

Dysplastic Cerebellar Gangliocytoma (lhermitte-Duclos)

Medulloblastoma

(Desmoplastic

Variant) (Left) Coronal T2WI MR shows enlarged, dysplastic-appearing cerebellar folia with striated, mixed hyper-lisointense mass in right cerebellum =::a. (Right) Axial T2WI MR in a 26 year old male shows inhomogeneously hyperintense mass in lateral cerebellum Mass enhanced heterogeneously. Desmoplastic medulloblastoma is most likely etiology; were this a child, atypical teratoid rhabdoid tumor would be a

=-

consideration.

(Lefl) Axial T7 C+ MR shows a large, inhomogeneously enhandng, destructive, transcalvarial mass with both intracranial

~

and

extracranial ~ components. (RighI) Sagittal TlWI MR shows a midline mass in

=

front of and indenting

the

pons 81. Note the loss 01 cortical margin in the clivus ~ from which the mass originates. The mass was extremely hyperintense on T2Wt consistent with its notochordal remnant origin.

I 7 43

POSTERIOR

FOSSA NEOPLASM,

DIFFERENTIAL DIAGNOSIS Common • Pilocytic Astrocytoma • Medulloblastoma (PNET-MB) • Ependymoma • Brainstem Glioma, Pediatric

c: ns •...

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c: ns

Less Common • Ganglioglioma • Schwannoma • Meningioma, CPA-lAC • Hemangioblastoma • Choroid Plexus Papilloma Rare but Important • Anaplastic Astrocytoma • Atypical Teratoid-Rhabdoid Tumor • Choroid Plexus Carcinoma • Medulloblastoma Variants • Medulloepithelioma • Dysplastic Cerebellar Gangliocytoma

ESSENTIAL INFORMATION

I 7 44

Key Differential Diagnosis Issues • Most common pediatric posterior fossa (PF) tumors o Medulloblastoma (PNET-MB) o Astrocytomas • Pilocytic astrocytoma (PA) • Infiltrating "glioma" (astrocytoma, WHO grade II) o Ependymoma • Imaging o Findings on conventional MR overlap o Location helpful in differential diagnosis • Tectum, cerebellum: PA • Pons: Diffusely infiltrating astrocytomas • Midline (vermis, fourth ventricle): PNET-MB,PA • Fourth ventricle + lateral recess/CPA mass: Ependymoma o DWI, MRS (normalized to water) • Can discriminate between pediatric PF tumors • PNET-MB,atypical teratoid-rhabdoid tumor (ATRT)show DWI restriction o Examine entire neuraxis in child with PF tumor prior to surgery! • Tl C+ essential (look for CSF spread) • History, PE (e.g., cutaneous markers) important

PEDIATRIC

Helpful Clues for Common Diagnoses • Pilocytic Astrocytoma o Child with cystic cerebellar mass + mural nodule o Solid component low density NECT, high signal T2 • Medulloblastoma (PNET-MB) o Early childhood: Solid vermis mass extends into, fills, &/or obstructs 4th ventricle o Later onset: Lateral cerebellar mass o Hypercellular: t Density on NECT, I T2 o DWI: Restricts o 2-5% have nevoid basal cell carcinoma (Gorlin) syndrome (BCCS) • Typically seen with desmoplastic variant • Look for jaw cysts, bifid ribs, ete. • XRT can lead to induced basal cell carcinomas, other intracranial neoplasms within irradiated field • Ependymoma o Extrudes through 4th V outlet foramina into cisterns o Coarse calcifications o Diffusion restriction uncommon, may predict anaplastic behavior • Brainstem Glioma, Pediatric o Tectal plate glioma • NECT: Increased density progresses to Ca++ • CECT/MR: Faint or no enhancement o Pontine glioma • Enlarged pons engulfs basilar artery • Enhances late in course, rarely at diagnosis o Dorsal exophytic glioma • Tumor protrudes into 4th ventricle • If large, may be difficult to differentiate from PA • Look for FLAIRsignal change in dorsal brainstem or peduncles Helpful Clues for Less Common Diagnoses • Ganglioglioma o Brainstem most common PF site o Look for expansion of nucleus cuneatus/gracilis • Schwannoma o Vestibular schwannoma (lCA/CPA) looks like "ice cream on cone" 01'2 hyperintensity helps differentiate from meningioma o Multiple in NF2

POSTERIOR

FOSSA NEOPLASM,

• Meningioma, CPA-lAC o Broad dural base, covers lAC o Variable signal, but T2 hypointensity common o Hyperostosis, tumoral calcifications o May have intra- or juxtatumoral cyst(s) • Hemangioblastoma o Late teen or adult o Intra-axial (cerebellum> medulla, cord) • Cyst + nodule> solid • Solid component shows flow voids, enhances avidly • Multiple lesions diagnostic of von Hippel-Lindau (VHL) o Avidly enhancing mural nodule abuts pia o Look for visceral markers of VHL in any child/young adult with hemangioblastoma • Choroid Plexus Papilloma o Frond-like 4th V or CPA tumor o Avidly enhancing o Hydrocephalus common Helpful Clues for Rare Diagnoses • Anaplastic Astrocytoma o Infiltrating mass involves predominantly white matter o Enhancement none to sparse or patchy enhancement o Ring enhancement suggests progression to GBM • Atypical Teratoid-Rhabdoid Tumor o Imaging similar to PNET-MBplus • ATRTpatients generally younger • Cysts, hemorrhages more common

•

•

•

•

PEDIATRIC

• CPA involvement more common • Frequent metastases at diagnosis o Both ATRT,PNET-MB show diffusion restriction Choroid Plexus Carcinoma o Similar to CPP plus • Cysts, necrosis, bleeds • CSF/ependymal/parenchymal spread Medulloblastoma Variants o Desmoplastic medulloblastoma (MB) • 5-25% of all medulloblastomas • 55-60% of PNET-MBs in children < 3 Y • PNET-MBin older children, young adults often also desmoplastic variant • Desmoplastic subtype of MB in children < 2 is major diagnostic criterion for basal cell nevus syndrome (Goriin syndrome) • Nodular collections of neurocytic cells bounded by desmoplastic zones • Lateral (cerebellar) location o MB with extensive nodularity (MBEN) • Formerly called "cerebellar neuroblastoma" • Usually occurs in infants • Gyriform or "grape-like" appearance • May mature - better prognosis Medulloepithelioma o Rare embryonal brain &/or ocular tumor o Inhomogeneous signal, enhancement Dysplastic Cerebellar Gangliocytoma o Diffuse or focal hemispheric mass o Thick cerebellar folia with "striated" appearance o Evaluate for Cowden syndrome

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Pilocytic Astrocytoma

Sagittal T1 C+ MR shows a typical tumor cyst with enhancing mural nodule There is hydrocephalus and protrusion of the cerebellar tonsils ~ through the foramen magnum facquired Chiari 1)_

=_

=

Axial T2WI MR shows increased signal of the solid component of the mass. Interstitial edema ~ is present in the temporal lobes_

I 7 45

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POSTERIOR

E

FOSSA NEOPLASM,

PEDIATRIC

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Medulloblastoma (Left) Sagiltal T2WI MR

shows a hyperintense mass

=:I filling

and expanding the 4th ventricle. The tumor docs not extend through the 4th ventricular outlet foramina. There is hydrocephalus with acquired tonsillar herniation ~. (Rigllt) Coronal T I C+ MR

shows heterogeneous enhancement SII of the 4th ventricular I'N£T-MB.

(Lefl) Sagiltal T1 WI MR shows a large tumor filling the 4th ventricle =:I and extruding SIIthrough the obex into the upper spinal canal. (RighI) Axial T2WI MR shows a heterogeneous tumor expanding and extruding through the right foramen of Luschka SII. There are a few coarse calcific foci ~ within the tumor.

(Left) Sagittal T2WI MR in an infant with a teclal plate

I 7 46

glioma shows marked hydrocephalus involving the 3rd and lateral ventricles. The corpus callosum is stretched thin =:I. The tectal plate [;8 is bulbous and slightly increased in signal intensity. The aqueduct of Sylvius is obstructed IdJ. (RighI) Sagiltal T2WI MR in this child with a diffusely infiltrating pontine glioma shows homogeneous signal intensity of the expanded ponsSll.

(PNET-MB)

Medulloblastoma

(PNET-MB)

POSTERIOR

Brainstem Glioma,

FOSSA NEOPLASM,

PEDIATRIC

Pediatric (Lefl) Sagittal T1 C+ MR shows marked expansion of the medulla 81 by a complex mass with inlralesional cystic areas and avid, but heterogeneous, enhancement

in this child

with dorsal exophylic brainstem glioma. The inFerior 4th ventricle is deformed by the protruding mass. (RighI) Sagittal T2WI MR shows marked expansion of the medulla and upper cervical spinal cord 81. The inFerior 4th venuicle is deformed ~ by the dorsally protruding mass.

Schwannoma

Schwannoma (Left) Axial T2WI MR shows

a bulky heterogeneous right cerebelloponline angle mass crosses the midline. There is also

a which extensive

remodeling

of the

right internal auditory canal t=lI by this schwannoma. (RighI) Axial T1 C+ MR in another child shows small bilateral vestibular schwannomas. The right

lesion E:I assumes the appearance

of "ice cream

on

a cone". Both demonstrate intra labyrinthine extension ~.

Meningioma,

CPA-lAC

Meningioma,

CPA-lAC (Left) Axial T2WI MR shows a low signal, lobular cerebellopontine angle mass ~ with hyperostosis 81 of the adjacent petrous apex. There is mild rota lion of the medulla due to mass effect. (RighI) Coronal NECT shows diffuse hyperostosis 81 adjacent to the meningioma

~.

I 7 47

POSTERIOR FOSSA NEOPLASM, PEDIATRIC

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(Left) Sagittal T2WI MR shows a solid component with multiple flow voids ~ a cyst EB and edema of the medulla and upper cervical cord 81. (Right) Sagittal T7 C+ MR shows the cyst 8110 better advantage than the prior T2WI image. Here, the cyst's contents have slightly increased signal.

"0

c

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(Left) Axial T2WI MR shows multiple Foci of abnormal signal intensity in the peripheral right cerebellar hemisphere and in the cerebellar while maller adjacent 10 the lateral recess of the 4th ventricle. (Right) Axial T7 C+ MR shows enhancement =:I Following

-=

gadolinium

administration.

The lesion adjacent to the 4th ventricle lateral recess has ill-defined margins.

Atypical Teratoid-Rhabdoid (Left) Sagittal T2WI MR

shows extensive posterior (ossa

I 7 48

a pineal

region

and intraventricular low signal intensity masses. MultiFocal deposits of tumor at diagnosis are strongly suggestive of an atypical teratoid-rhabdoid tumor. (Right) Sagittal T7 C+ MR shows quite variable enhancement of the posterior Fossa~ pineal region=, and intraventricular B tumor deposits. There is marked hydrocephalus.

Tumor

Atypical

Teratoid-Rhabdoid

Tumor

POSTERIOR

FOSSA NEOPLASM,

en ,.-

PEDIATRIC

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Choroid

Plexus Carcinoma

Choroid

Q)

Plexus Carcinoma (Left) Axial T1 C+ MR shows a slightly heterogeneous, but avidly enhancing, mass within the right foramen of Luschka There is an associated cyst 81. (Right) Axial T2WI MR in a different child unde'going treatment for choroid plexus carcinoma shows a large skull base metastatic deposit E.I.

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Medulloepithelioma (Left) Axial NECT in a one day old infant shows a dense, lobular mass filling the posterior fossa. Foci of

increased density superimposed in the mass are due to hemorrhage. Note the blood-CSF level in the dilated infundibular recess 81. (Right) Coronal TI C+ MR in the same infant following biopsy shows extension into the spinal canal [;8 Cas in the ventricular system follows

=

neurosurgical

intervention.

There is extensive ependymal seeding

=.

(Left) Axial T1 C+ MR shows mass involving the left cerebellar hemisphere. Preservation of

a large nonenhancing

the cerebellar

=-

folia pallern,

or "striated cerebellum" is characteristic for dysplastic cerebellar gangliocytoma (Lhermitte-Duclos). This disease has a strong association with Cowden syndrome. (Right) Axial T2WI MR again shows the pattern of a "striated cerebellum"

=-

I 7 49

SEClilON 8

SellalJuxtasellar, Pineal Region Anatomically Based Differentials Pineal Region Mass, General Pineal Gland Mass Quadrigeminal Cistern Mass Pineal + Suprasellar Lesions Sella/Pituitary Normal Variants Sellar/]uxtasellar Calcification Enlarged Pituitary Gland Intrasellar Lesion Cystic Intrasellar Mass Suprasellar Mass, General Suprasellar Masses, Pediatric Suprasellar Cystic Mass Calcified Suprasellar Mass Enhancing Suprasellar Mass Absent/Thin Infundibular Stalk Thick Infundibular Stalk Hypothalamus Lesion

Modality-Specific

1-8-2 1-8-6 1-8-8 1-8-10 1-8-12 1-8-14 1-8-18 1-8-20 1-8-22 1-8-24 1-8-30 1-8-36 1-8-40 1-8-42 1-8-44 1-8-46 1-8-48

Imaging Findings

Hyperdense Suprasellar Mass T1 Isointense Suprasellar Mass T1 Hyperintense Suprasellar Mass T1 Hypointense Suprasellar Lesion

1-8-52 1-8-54 1-8-56 1-8-58

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DIFFERENTIAL DIAGNOSIS Common • Pineal Cyst less Common • Cavum Velum Interpositum (CVI) • Meningioma • Pineocytoma • Arachnoid Cyst • Tectal Plate Glioma • Neurocysticercosis • Lipoma • Intracranial Hypotension • Medial Atrial Diverticulae (Obstructive Hydrocephalus) Rare but Important • Germinoma • Epidermoid Cyst • Dermoid Cyst • Vein of Galen Malformation

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Quadrigeminal cistern (QC) o Bounded by quadrigeminal plate, splenium, vermis, & tentorial margin o Extends between layers of 3rd ventricle tela choroidea o Contents: Caudal internal cerebral veins ...• vein of Galen, distal parts of quadrigeminal artery, PCA P4 segment, & C 9 exit o Synonyms: Cisterna quadrigeminalis, cistern of great cerebral vein, cisterna venae magnae cerebri, Bichat canal, cisternal quadrigeminalis, & superior cistern

I 8 2

Helpful Clues for Common Diagnoses • Pineal Cyst o Homogeneous fluid-filled mass above & clearly distinct from tectum o 55-60% slightly T1 hyperintense to CSF; FLAIRdoesn't suppress; 60% enhance (partial/complete rim, nodular) o Cystic expansion of pineal in some females begins in adolescence, decreases with age o Can't distinguish from pineocytoma on basis of imaging studies alone

Helpful Clues for less Common Diagnoses • Cavum Velum Interpositum (CVI) o Axial MR/CT shows triangular-shaped CSF space between bodies of lateral ventricles o FLAIRsuppresses completely; no enhancement o Dilatation of velum interpositum, precise etiology unknown o Common in early infancy, rare in adults • Meningioma o Avidly enhancing mass, trapped pools of CSF common, focal calcification may represent displaced pineal o Arise from posterior portion of the velum interpositum, falx, or tentorium o Velum interpositum meningiomas: M = F, in both pediatric & adult populations o May be symptomatic from compression of quadrigeminal plate • Pineocytoma o Enhancing, circumscribed pineal mass which "explodes" pineal Ca++ o May mimic pineal cyst or pineoblastoma o May compress but does not invade adjacent structures o - 45% of pineal parenchymal tumors • Arachnoid Cyst o Sharply demarcated extra-axial cyst that follows CSF attenuation/signal o Quadrigeminal arachnoid cysts (AC) are 3rd most common infra tentorial AC o Symptoms depend on compression of brain stem, cerebellum, & aqueduct o Elevated ICP & sudden death have been reported • Tectal Plate Glioma o Tectal distortion or thickening by localized mass o Tl hypointense, T2 hyperintense, ± enhancement o Onset aqueductal stenosis often without associated brain stem signs o Reported as indolent lesions often remaining stable in size for many years • Neurocysticercosis o May involve cisterns> parenchyma> ventricles o Basal cistern cysts may be racemose o Cysts variable, typically 1 cm, range from 5-20 mm and contain a 1-4 mm scolex

PINEAL REGION

MASS, GENERAL

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Cystic lesion isointense to CSF,may see discrete, eccentric scolex • Lipoma o Well-delineated lobulated extra-axial mass with fat attenuation/intensity 040-50% interhemispheric fissure (over corpus callosum) o Ca++ varies from none to extensive o Fat-suppressed MR is diagnostic • Intracranial Hypotension o Corpus callosal descent can efface QC o Sagittal shows brain descent in 40-50% o Diffusely, intensely enhancing dura in 85% o Bilateral subdural fluid collections in 15% • Medial Atrial Diverticulae (Obstructive Hydrocephalus) o Mechanism • Massive ventricular dilatation causes stretching & dehiscence of fornix unilateral or bilateral diverticula of inferior medial atrial wall • Enlargement of pial pouch creates subarachnoid cyst that may herniate through incisura into QC o Imaging • Focal dehiscence of medial atrial wall • Draping of medial atrial wall over free margin of tentorium with continuity of CSF around tentorial edge • Contralateral internal cerebral vein displaced • Presence of septa separating diverticulum from 3rd ventricle o

Helpful Clues for Rare Diagnoses • Germinoma o Pineal region mass that "engulfs" the pineal gland o Tl/T2 iso- or hyperintense to gray matter o Strong uniform enhancement, ± CSF seeding • Epidermoid Cyst o Lobulated, irregular, CSF-like mass with "fronds" insinuates cistern o FLAIRusually doesn't completely null; diffusion yields high signal restriction 00.2-1.8% of all primary intracranial tumors o Congenital inclusion cysts; rare malignant degeneration into squamous cell CA • Dermoid Cyst o Fat appearance: Use fat suppression sequence to confirm o Rupture - fat droplets in subarachnoid spaces with extensive enhancement possible from chemical meningitis o < 0.5% of primary intracranial tumors o Rare malignant degeneration into squamous cell carcinoma • Vein of Galen Malformation o Dilated arteries feeding into large midline venous pouch o Thin sagittal images define anatomy & relationship to cerebral aqueduct o < 1% cerebral vascular malformations at any age o Neonatal> infant presentation most common; rare adult presentation

Pineal Cyst

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shows an isoinlense mass

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wilh flow voids ~. Visualization of a normal pineal gland ~ & elevation of midbrain lectum ~ helps exclude pineal tumors from lhe differential diagnosis. (Right) Axial CECT shows a lypical CT case of a pineocytoma with "exploded" pre-existing calcificalion Also note the typical lack of significant mass effect.

=.2.

Arachnoid (Left) Sagillal T1 WI MR

shows an arachnoid cyst extending posteroinferiorly from the quadrigeminal

cistern, compressing the superior vermis inferiorly -7. (Right) Sagittal T2WI MR demonstrales a typical tectal plate low grade astrocytoma as a predominantly homogeneous, slightly hyperintense mass involving the lectal plale proper EB

(Left) Axial T2WI FS MR shows multiple cysticercosis cysts in the quadrigeminal cistern atrium right lateral ventricle ~ (Courtesy E. Bravo, MO). (Right) Axial T1WI MR reveals a fat-intenSity lesion =.2 within the quadrigeminal cistern exerting mass effect

upon the quadrigeminal plate (R> L). Fat suppression (not shown) confirmed lipoma.

I 8 4

Cyst

Tecta I Plate Glioma

en

PINEAL REGION MASS, GENERAL

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Intracranial Hypotension

Medial Atrial Diverticulae (Obstructive Hydrocephalus) (Left) Sagittal T1 C+ MR shows cisternal effacement by splenium impacting internal cerebral veins ~ & quadrigeminal plate BI. Note 1055 of suprasellar cistern & dural enhancement . (Right) sagillal T1 WI MR shows an atrial diverticulum ~ that has protruded through the lateral ventricle medial waif

=

under the Fornix

Note

the severely compressed displaced 4th ventricfe BI.

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Germinoma (Left) sagillal T1 C+ MR shows an enhancing germinoma !l±. Note compression of the tectal plate and CsF tumor seeding BI. (Right) Axial T2WI MR shows a T2 hyperintense lobulated mass

=

centered in ambient cistern

extending into suprasellar & quadrigeminal cisterns BI displacing the quadrigeminal plate ~_

~

Dermoid Cyst

Vein of Galen Malformation (Left) Axial CECT demonstrates a low density ruptured dermoid in the pineal region BI with fat droplets in subarachnoid spaces Note vemricular shuml!:J placed for chemical meningitis. (Right) Sagittal T1WI MR shows a large well-delineated area of signal 1055behind the 3rd ventricle BI. Note phase artifact from high flow I!:J & large persistent primitive fa/cine sinus

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I 8 5

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PINEAL GLAND MASS

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DIFFERENTIAL DIAGNOSIS Common • Pineal Cyst • Germinoma • Pineocytoma Less Common • Teratoma • Pineoblastoma Rare but Important • Retinoblastoma (Trilateral) • Germ Cell Neoplasms, Malignant • Diffuse Astrocytoma, Low Grade

NOS

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ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Pineal Cyst o Homogeneous fluid-filled pineal mass o May see rim enhancement o Most are < 1 cm but may be up to 2 cm • Germinoma o Most common germ cell tumor (GCT) & pineal tumor o Homogeneous, hyperdense mass with enhancement, ± CSF seeding o Central, "engulfed" Ca++ classic • Pineocytoma o Demarcated round or lobular mass, typically with Ca++ o Strong, homogeneous enhancement o May compress adjacent structures, but no invasion

I 8 6

Helpful Clues for Less Common Diagnoses • Teratoma o 2nd most common GCT & pineal tumor o Midline mass containing Ca++, soft tissue, cysts, & fat; variable enhancement • Pineoblastoma o Highly malignant, primitive embryonal tumor of pineal gland o Large, heterogeneous pineal mass with "exploded" peripheral Ca++ & hydrocephalus Helpful Clues for Rare Diagnoses • Retinoblastoma (Trilateral) o Bilateral ocular tumors + midline intracranial neuroblastic tumor o Trilateral rare: 80% pineal, 20% suprasellar • Germ Cell Neoplasms, Malignant NOS o Uncommon, highly malignant tumors: Choriocarcinoma, endodermal sinus tumor, embryonal cell carcinoma, mixed o Heterogeneously enhancing pineal mass o Characteristic elevation of serum tumor markers: Choriocarcinoma, ~-hCG; endodermal sinus tumor, AFP; embryonal cell carcinoma, ~-hCG & AFP • Diffuse Astrocytoma, Low Grade o Rarely arise from pineal gland o Pilocytic astrocytoma most common Alternative Differential Approaches • Helpful to divide pineal gland masses into o Pineal parenchymal masses o Germ cell tumors o "Other cell" tumors/lesions

Pineal Cyst

Pineal Cyst

Axial FLAIR MR shows a pineal mass that does not suppress, which is typical. Pineal cysts are very common, with a 1-4% prevalence at imaging. They are most often asymptomatic.

Axial T1 C+ MR shows a pineal mass with no enhancement, typical of a pineal cyst. If there is rim or

nodular (rare) enhancement, it may not be distinguishable from a pineocytoma on imaging alone.

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Pineocytoma (Left) Axial T1 C+ MR shows a well-defined, enhancing pinea/wmor that projects into the posterior 3rd ventricle. The patient is a male adolescent with Parinaud syndrome, typical presentation for germinoma. (Right) Axial T1 C+ MR shows a pineal mass with peripheral & central enhancement.

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Enhancement

of pineocyloma can be solid, peripheral, or both. Imaging of a pineocytoma may mimic a pineal cyst or pineoblastoma.

(Left) Axial T1 WI MR shows a heterogeneous pineal region mass with small hyperintense foci representing fat Note associated hydrocephalus. (Right) Axial T1 C+ MR shows a cystic & solid pineal

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mass

with

heterogeneous

enhancement.

Note

associated hydrocephalus. Pineoblastoma is a highly maJignanllumor

with poor

survival. Spina! screening should be performed, as up to 45% present with spinal dissemination.

(Left) Axial T1 C+ MR shows an enhancing mass in the pineal gland with associated hydrocephalus in this patient with bilateral retinoblastoma. Trilateral disease is rare and has a dismal prognosis. (Right) Axial T1 C+ MR shows a heterogeneously enhancing mass, a mixed malignant GCT with

embryonal carcinoma elements. [mbryonal carcinoma is typically part of a mixed malignant GCT. These types of tumors are solid masses, often with cysts & hemorrhage.

I 8 7

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DIFFERENTIAL DIAGNOSIS Common • Metastases Less Common • Cavum Velum Interpositum (CVI) • Arachnoid Cyst • eurocysticercosis • Ascending Transtentorial Herniation Rare but Important • Lipoma • Epidermoid Cyst • Dermoid Cyst • Vein of Galen Malformation

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Quadrigeminal cistern (QC) lesions are smaller subset of "pineal region masses" o Bounded by quadrigeminal plate, splenium, vermis, & tentorial margin o Extends between layers of tela choroidea o Contents: Caudal internal cerebral veins, vein of Galen, peA (quadrigeminal or P3 segment), posteromedial choroidal arteries, CNIVexit • Masses arising from QC itself (and its contents) < < those from nearby structures Helpful Clues for Common Diagnoses • Metastases o Linear &/or nodular enhancing lesions o Image entire neuraxis!

Metastases

I 8

Sagillal T7 c+ MR shows typical leptomeningeal (pia & arachnoid) metastases lID in the quadrigeminal cistern

as well as widespread throughout the cerebellar {olia.

8

Helpful Clues for Less Common Diagnoses • Cavum Velum Interpositum (CVI) o Axial MR/CT shows triangular-shaped CSF space between bodies of lateral ventricles o FLAIR suppresses completely • Arachnoid Cyst o Sharply demarcated extra-axial cyst that follows CSF attenuation/signal o No diffusion restriction • Neurocysticercosis o Cystic lesion isointense to CSF, may see discrete, eccentric scolex o Basal cistern cysts may be racemose • Ascending Transtentorial Herniation o Large posterior fossa mass --+ upward herniation of vermis --+ mass effect on quadrigeminal cistern ± obstructive hydrocephalus Helpful Clues for Rare Diagnoses • Lipoma o Well-delineated, lobulated, extra-axial mass with fat attenuation/intensity o Ca++ varies from none to extensive • Epidermoid Cyst o Lobulated, irregular, CSF-Iike mass o FLAIR usually doesn't completely null; diffusion yields high signal restriction • Vein of Galen Malformation o Dilated arteries feeding into large midline venous pouch o Look for prominent "flow voids" and phase artifact

Cavum Velum Interpositum

(CVI)

Sagillal T7WI MR reveals a well-defined cavum velum imerpasiwm isoinlense with CSF, displacing the internal cerebral veins inferiorly ~ and compressing the quadrigeminal cistern ~.

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(Left) Sagillal TI WI MR shows an arachnoid cyst compressing the vermis inferiorly widening the quadrigeminal cistern and extending into velum inlerposilum (Right) Sagittal STIR MR reveals multiple hyperintense CYSIS in the quadrigeminal cistern and basal subarachnoid spaces 811.

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lipoma (Left) Axial NECT shows complete effacement of the quadrigeminal cistern caused by upward herniation of the vermis through the tentorial incisura that also compresses the aqueduct ED. resulting in obstructive hydrocephalus with dilated 3rd and lateral venlricles ~. (Right) Sagillal T2WI MR demonstrates a fat intensity lipoma within the quadrigeminal cistern displacing the vermis which suppressed with T 1 fat suppression (not shown).

-=

Epidermoid

Cyst

Vein of Galen Malformation (Left) Axial TI WI MR demonstrates a lobulated CSF-like epidermoid within the quadrigeminal cistern. (Right) Sagillal TI WI MR demonstrates a prominent flow void within the quadrigeminal cistern from a vein of Galen malformation as well as associated fiswlae 81.

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DIFFERENTIAL DIAGNOSIS Common • Germinoma less Common • Lymphoma, Primary CNS • Metastases, Intracranial, Other Rare but Important • Germ Cell Neoplasms, Malignant • Retinoblastoma (Quadrilateral)

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ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Age may be a helpful differentiating feature • Diabetes insipidus is a common presenting feature of infundibular masses • Parinaud syndrome is a common presentation of pineal masses Helpful Clues for Common Diagnoses • Germinoma o Most common germ cell tumor o Hug midline near 3rd ventricle: 80-90% o Pineal region: 50-65%; suprasellar: 25-35% o Pineal + suprasellar - 10% o Hyperdense masses on CT o Homogeneous enhancement o CSF seeding common Helpful Clues for less Common Diagnoses • Lymphoma, Primary CNS o Homogeneous enhancing mass(es) along ependymal surface typical

o May involve sellar & pineal regions • Metastases, Intracranial, Other o Enhancing masses at gray-white junctions o May involve pineal & suprasellar regions o Primary tumor often known

Helpful Clues for Rare Diagnoses • Germ Cell Neoplasms, Malignant NOS o Uncommon, highly malignant tumors: Choriocarcinoma, endodermal sinus tumor, embryonal cell carcinoma, mixed germ cell tumor o Heterogeneously enhancing masses o Imaging cannot reliably differentiate o Characteristic elevation of serum tumor markers • Choriocarcinoma: ~-hCG; endodermal sinus tumor: AFP; embryonal cell carcinoma: ~-hCG & AFP • Retinoblastoma (Quadrilateral) o Bilateral calcified ocular tumors + midline neuroblastic tumors (pineal & suprasellar) o 40% are familial & account for nearly aJl bilateral & multilateral disease o Trilateral disease rare: 5-15% of familial lesions (80% pineal, 20% suprasellar) o Quadrilateral disease extremely rare o Dismal prognosis, < 24 month survival Alternative Differential Approaches • Pineal + suprasellar lesions in a child: Germinoma, germ cell neoplasms, retinoblastoma • Pineal + suprasellar lesions in an adult: Lymphoma, metastases

Germinoma

Germinoma

I 8

C + M R shows a mildly enhancing suprasellar & a small synchronous pineal mass 81 in this

Axial T1

mass ~

~ & suprasellar regions in this patient with CSF spread of germinoma. Enhancing tumor infiltrates the

patient who

10

C+ MR

Sagittal T1

Germinoma

presented

with diabetes insipidus.

was proved at biopsy.

ependyma

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of the (rontal horns

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(Left) Sagiltal TI C+ MR shows an enhancing mass in

:3

the suprasellar region that extends into the pituitary infundibulum SlI as well as along the du,a of the posterior

clivus

1'1:D.

Primary

lymphoma was found at biopsy Note prominent enhancement of the pineal gland presumed lymphoma. (Right) Sagiltal TI C+ MR shows resolution of the suprasellar mass, 5

=-

months after treatment.

also a normal appearance the pineal gland =:lI.

Note to

Germ Cell Neoplasms, Malignant NOS (Left) Sagiltal TI C+ FS MR shows enhancing masses in the suprasellar & pineal regions in a young male patient Imaging mimics a germinoma. Biopsy revealed an embryonal carcinoma. Elevation of serum markers ~-hCC & AFP is characteristic. (Right) Axial TI WI MR shows an enhancing pineal mass with hydrocephalus in this patient with bilateral retinoblastoma. Imaging represents trilateral disease with a pineal tumor;,

the most common location in trilateral disease.

Retinoblastoma (Quadrilateral)

Retinoblastoma (Quadrilateral) (Left) Axial CECT shows bilateral

calcified

masses in

this relinoblaslOma patient Bilateral orbital masses occur in 25-30% of patients with retinoblastoma. imaging

Brain

is important

to

search for trilateral or quadrilateral disease. (Right) Axial CECT shows a large enhancing suprasellar mass & dilatation of the temporal horn in this patient with bilateral retinoblastoma. The familial hereditary form accounts for essentially all multilateral disease.

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NORMAL

VARIANTS

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Beware: "Macroadenoma-appearing" pituitary in young males may be physiologic hyperplasia, not tumor! • Pituitary "IncidentalOIlla" o "Filling defects" in 15-20% of normal scans o Cystic changes common, may be transient • "Empty" Sella (ES) o Rarely (if ever) truly empty o Intrasellar CSF, pituitary gland flattened against sellar floor o Primary ES • Considered normal variant • Usually asymptomatic, incidental finding • 5-10% prevalence • Peak age 40-49 years o Secondary ES • Surgery, radiation, bromocriptine therapy • Sheehan syndrome (postpartum pituitary necrosis) o

DIFFERENTIAL DIAGNOSIS Common • Pituitary Hyperplasia (Physiologic) • Pituitary "lncidentaloma" • "Empty" Sella (ES) Less Common • "Bright" Pituitary Gland • Absent Posterior Pituitary "Bright Spot" • Small Sella Turcica • "]"-Shaped Sella Rare but Important • Paramedian ("Kissing") Internal Carotid Arteries

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Prior to evaluating sella/pituitary, essential to know patient age, gender o Maximum height varies with gender, age • 6 mm children • 8 mm males, postmenopausal females • 10 mm young females • 12 mm pregnant/lactating females Helpful Clues for Common Diagnoses • Pituitary Hyperplasia (Physiologic) o Enlarged pituitary gland • 10-15 mm, convex upwards • Enhances strongly, uniformly o May be indistinguishable from macroadenoma, lymphocytic hypophysitis

Helpful Clues for Less Common Diagnoses • "Bright" Pituitary Gland o Neonate: Adenohypophysis large, hyperintense on T1 WI o Size, signal! during first 6 weeks • Absent Posterior Pituitary "Bright Spot" o Neurohypophysis normally has short T1 o Commonly absent in central DI o Found in up to 20% of normal patients • Small Sella Turcica o Small or shallow bony sella can be normal o Causes pituitary gland to protrude upwards

Pituitary "Incidentaloma"

I 8 12

Coronal T1 c+ MR in a young postpartum lactating female shows an upwardly bulging pituitary gland Physiologic hyperplasia wid, gland measured almost 12 mm in height

=.

Sagittal T1 C+

MR in asymptomaUc adult shows possibly a small Rathke cleft cyst Such findings are common at both imaging (15-20% of cases) and autopsy.

nonenhancing pituitary cyst

SELLA/PITUITARY

NORMAL

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VARIANTS

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"Bright" Pituitary Gland

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(Left) Sagittal T1 Wt MR in an asymptomatic patient shows a primary empty sella with downward herniation of CSF into the suprasellar cistern The pituitary gland is flallened against the sellar floor 81. (Right) Sagillal T1WI MR in newborn shows a large, hyperintense adenohypophysis a normal finding.

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Small Sella Turcica (Left) Sagiltal T1 C+ MR shows a small, shallow sella turcica~. This causes the normal-sized pituitary gland to protrude superiorfy,

=

mimicking

macroadenoma.

(Right) Coronal T1 C+ MR in the same patient as the previous image shows a (fat shallow sella turcica SI, causing upward bulging of the pituitary gland Gland height measured 9 mm,

=.

normal

Paramedian Small Sella Turcica

("Kissing") Internal Arteries

in this young woman.

Carotid (Left) Sagillal T1 WI MR shows a small, shallow sella and pituitary 81 in a patient with Kallmann syndrome with hypopituitarism. Small sella a/so occurs as a normal

=

variant,

indistinguishable

on

imaging alone. (Right) Axial Tf WI MR shows "flow voids" of both cavernous internal carotid arteries (lCAs), which curve much more medially than usual "Kissing carotids" are normal variants.

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I 8 13

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SELLAR/JUXTASELLARCALCIFICATION

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DIFFERENTIAL DIAGNOSIS Common • Physiologic Calcification, Vascular • Physiologic Calcification, Dura • Atherosclerosis, Intracranial • Saccular Aneurysm • Meningioma • Craniopharyngioma • eurocysticercosis Less Common • Astrocytoma a Pilocytic Astrocytoma a Diffuse Astrocytoma, Low Grade a Pilomyxoid Astrocytoma a Chordoid Glioma • Dermoid Cyst • Arteriovenous Malformation Rare but Important • Cavernous Malformation • Chordoma, Clivus • Pituitary Macroadenoma • Chondrosarcoma, Skull Base • Rathke Cleft Cyst • Benign Nonmeningothelial Tumors a Chondroma a Osteochondroma a Osteoma

ESSENTIAL INFORMATION

I 8 14

Key Differential Diagnosis Issues • Is patient asymptomatic? • Is calcification physiologic or pathologic? a Physiologic • Vascular (age-related changes of ASVD) • Dural (petroclinoid ligament often calcified) a Pathologic • Look for associated mass in/around sella, cavernous sinus • Anatomic sublocation important a Dura (cavernous sinus, tentorium, petroclinoid ligaments) calcifies but less often than falx a Arteries (cavernous/supraclinoid ICA) physiologic Ca++ common a Pituitary, infundibulum, hypothalamus almost never show physiologic Ca++

Helpful Clues for Common Diagnoses • Physiologic Calcification, Vascular a ]uxtasellar dura, vessels, not brain • Atherosclerosis, Intracranial a Some age-related ASVD Ca++ normal, physiologic a Relationship to stenosis, stroke controversial • Thickness of Ca++ plaque does not correlate directly with luminal stenosis • Dense, globular Ca++ may be more significant than mural/laminar • Some authors suggest high grade of cavernous ICA Ca++ correlates with small (not large) vessel ischemia • Saccular Aneurysm a Supra/juxtasellar > intracavernous a Mural Ca++ common a Can be rim, globular a Aneurysm often partial/completely thrombosed • Meningioma a Ca++ 20-25% • Diffuse or focal • Solid ("brain rock") or scattered • Ca++ pattern highly variable • Psammomatous ("sand-like") or "sunburst" > globular> rim a Look for dural "tail" a Look for changes in adjacent planum sphenoidale a Can cause blistering, hyperostosis, hypertrophied ethmoid or sphenoid sinuses ("pneumosinus dilatans") • Craniopharyngioma a In children, 90% cystic, 90% Ca++ (rim, globular) a Adults often solid with globular Ca++ • Neurocysticercosis a Healed racemose NCC in basal cisterns may Ca++ Helpful Clues for Less Common Diagnoses • AstrocytOIua a Pilocytic Astrocytoma • Common in optic chiasm/hypothalamus/3rd ventricle (2nd most common location after cerebellum) • Enhancement varies (none to striking) • Ca++ uncommon in supratentorial PAs! a Diffuse Astrocytoma, Low Grade

SELLAR/JUXTASELLAR

• WHO grade II may calcify but uncommon in this location • No enhancement o Pilomyxoid Astrocytoma • Rare tumor; common location • Hemorrhage common, Ca++ uncommon o Chordoid Glioma • Newly described distinct tumor entity • Hypothalamus/anterior 3rd ventricle mass • Ovoid, well-circumscribed • Usually solid mass; may have associated cysts (rare) • Hyperdense on NECT • Ca++ uncommon • Hypointense on T1-, iso- to mildly hyperintense on T2WI • Enhances strongly, usually uniformly • Dermoid Cyst o Sellar/parasellar/frontonasal region most common site o Unilocular fat-like cyst o Look for "droplets" in sulci, cisterns (ruptured dermoid) o 20% have capsular Ca++ • Arteriovenous Malformation o Supra/juxtasellar < hemispheres o 25-30% Ca++ Helpful Clues for Rare Diagnoses • Cavernous Malformation o Common lesion that commonly shows Ca++

Physiologic

Calcification,

Dura

Axial bone CT shows physiologic calcification in both cavernous internal carotid arteries as well as dura of the cavernous sinus wall dorsum sellae P.:iJ and both petroclinoid ligaments 81.

=

CALCIFICATION

Hypothalamus, juxtasellar lesions uncommon Chordoma, Clivus o 35% arise in skull base o Epicenter at sphenooccipital synchondrosis o Destructive, invasive o Often have "thumb-like" posterior tumor extension through clivus o 50% contain ossific fragments of destroyed bone on NECT o Hyperintense on T2WI Pituitary Macroadenoma o Most common lesion in this location o Only 1-2% Ca++ o Can be very invasive, destructive Chondrosarcoma, Skull Base o Epicenter at petro-occipital fissure o 50% have chondroid calcification in tumor matrix (arcs, rings) o Hyperintense on T2WI o Enhance strongly, heterogeneously o Whorls of enhancing lines within tumor matrix Rathke Cleft Cyst o Only 10-15% Ca++ vs. > 90% of craniopharyngioma o Calcified RCC may be indistinguishable Benign Nonmeningothelial Tumors o Chondroma, osteochondroma, osteoma may all show Ca++ in cap or tumor matrix o Rare cause of juxtasellar Ca++ o

•

•

•

•

•

Atherosclerosis,

III

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(1)

1il <-

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1il .""

Intracranial

Axial NEeT shows prominent calcific changes in both supraclinoid internal carotid arteries 11m caused by atheroscferosis.

I 8 15

c:

SELLAR/JUXTASELLAR CALCIFICATION

o

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Ul

ctl

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Saccular Aneurysm (Left) Axial aCT shows a giant, mostly thrombosed, saccular aneurysm. Note ring enhancement SI of the thrombosed segment as well as globular and rim PJ:J calcification. (Right) Axial CECT shows an extensive plaque-like calcification along the optic nerve sheath and left anterolateral cavernous sinus E1.

=

=

nl OJ

-"(f)

Craniopharyngioma

=

(Left) Axial NECT shows rim and globular PJ:J calcification in a mufticystic suprasellar mass in child. Note fluid-fluid level SI. Most calcified suprasellar rnasses in children are craniopharyngiomas. (Right) Axial NECT shows punctate Ca++ in the suprasellar and ambient cisterns from

=

chronic racemose cysticercosis. (Courtesy E. Bravo, MOJ.

Pilomyxoid (Left) Axial NECT shows calcification

=

hypothalamic/suprasellar mass in 12 year old child. Diagnosis: Pilomyxoid variant of pi/oeytie astrocytoma. (Right) Axial NECT in this 48 year old with progressive visual decline shows hyperdense suprasellar mass with globular calcifications Pre-operative diagnosis was papillary subtype of

=.

craniopharyngioma.

Chordoid glioma of 3rd

I 8 16

ventricle

surgery.

was found at

Astrocytoma

Neurocysticercosis

SElLAR/JUXTASElLAR

en

CALCIFICATION

~ c:

III

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tlJ

Dermoid Cyst

Arteriovenous Malformation

III

(Left) Axial NECT shows a mass with fat-debris level E!llI extending from the suprasellar cistern into the sylvian fissure. Note calcification ~ and fat droplets in CSF from a ruptured dermoid. (Right) Axial NECT shows a slightly hyperdense calcified E!llI mass in the right medial temporal lobe. CECT scans showed typical findings of

=

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arteriovenous

malformation.

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to

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Cavernous Malformation

Chordoma, Clivus (Left) Axial NECT shows a very large, partially calcified mass 6>- extending inferiorly from the ventricles into the

hypothalamus. (Right) Axial CECT shows destructive lesion of central skull base encasing both internal carotid arteries and containing flecks of residual bone or calcifications ~_

Pituitary Macroadenoma

Chondroma (LeFI) Coronal CECT shows a large, lobulated, calcified -1>1 intra- and suprasellar mass that encases the right internal carotid artery [;B Only '-2% of macroadenomas calcify. (Righi) Coronal CECT shows an inlrasellar mass with dense globular calcification typical of benign chondroma. No stalk was found connecting the chondroma to parent bone. (Courtesy L. Cromwell, MO).

=-

I 8 17

ENLARGED PITUITARY GLAND

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DIFFERENTIAL DIAGNOSIS Common • Pituitary Hyperplasia • Pituitary Microadenoma • Pituitary Macroadenoma less Common • Neurosarcoid • Langerhans Cell Histiocytosis • Lymphocytic Hypophysitis • Pituitary Macroadenoma (Mimic) Rare but Important • Intracranial Hypotension • Meningioma • Metastases to Gland/Stalk • Dural A-V Fistula • Pituicytoma • Pseudotumor, Intracranial • Lymphoma, Primary CNS • Leukemia

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Not all "enlarged pituitary glands" are abnormal! o Size/height varies with gender, age • Children = 6 mm • Males, postmenopausal females = 8 mm • Young menstruating females = 10 mm (can bulge upwards) • Pregnant, postpartum lactating females = 12mm

Enhances strongly, uniformly • 15-20% have incidental cyst or nonfunctioning microadenoma (pituitary "incidentaloma") • Variants/mimics of "enlarged pituitary" o "Pseudoenlargement" secondary to unusually shallow bony sella o Medially positioned cavernous internal carotid arteries ("kissing carotids") may make gland appear enlarged o

Helpful Clues for Common Diagnoses • Pituitary Hyperplasia o Can be normal (young menstruating females) o Enlarged gland ± upward bulging o May be related to end-organ failure or neuroendocrine tumors • Pituitary Microadenoma o May enlarge gland o Best identified with dynamic, contrast-enhanced MR • Pituitary Macroadenoma o Pituitary gland can't be distinguished from mass o Enhances strongly, often heterogeneously Other Essential Information • Venous congestion (intracranial hypotension, dAVF) can enlarge gland • Beware: Child or young adolescent male with "pituitary adenoma" most likely has pituitary hyperplasia, not neoplasm! o Evaluate for end-organ failure (e.g., hypothyroidism)

Pituitary Hyperplasia

I 8 18

Coronal

TI

c+

=

MR shows

a

physiologically

enlarged

pituitary gland in this 28 year old lactaUng woman. The gland measures nearly 12 mm in height. Follow-up scan 1 year laler was normal.

Coronal TI c+ MR in a 51 year old man shows mildly enlarged pituitary gland I:] measuring 11mm in height. Note

faint area of slightly

mm microadenoma

less enhancement

found at surgery.

~.

An 8

ENLARGED PITUITARY GLAND Ql

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Neurosarcoid (Left) Sagittal Tl WI MR shows enlarged pituitary gland that elevates optic chiasm SlI. Enlarged gland is almost ;sointense with brain in this example of classic macroadenoma. (Right) Coronal Tl C+ MR shows a diffusely enlarged pituitary gland with subtle dural thickening along the floor of the middle cranial fossa SlI. This proved to be

=

=

neurosarcoidosis.

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Langerhans Cell Histiocytosis (Left) Coronal T I C+ MR shows a uniformly enlarged, enhancing pituitary gland SlI with upward extension and displacement of the optic chiasm in this child with known histiocytosis. (Right) Sagittal Tl C+ FS MR shows enlargement of the pituitary gland and infundibular stalk. The lesion resolved with

=

corlicosteroids and endocrine replacement.

Pituitary Macroadenoma

(Mimic)

Intracranial

Hypotension (Left) Sagittal Tl WI MR shows a very shallow bony sella SlI with optic chiasm draped over the pituitary. The gland measures 9 mm, which is normal in 79 year old women. "Pseudo-enlarged" gland. (Right) Sagittal TlWI MR shows sagging midbrain. Note upward bulging pituitary gland with draping of the optic chiasm over the gland in this patient with postural hypotension, intractable headaches.

=

=

I 8 19

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INTRASEllAR lESION

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DIFFERENTIAL DIAGNOSIS Common • Pituitary Hyperplasia • Pituitary Microadenoma • Empty Sella less Common • Pituitary Macroadenoma • Rathke Cleft Cyst • Craniopharyngioma • Neurosarcoid Rare but Important • Lymphocytic Hypophysitis • Intracranial Hypotension • "Kissing Carotid Arteries" • Saccular Aneurysm • Meningioma • Metastasis to Gland/Stalk • Lymphoma, Primary CNS • Dural A-V Fistula • CNS Siderosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Not all "enlarged pituitary glands" are abnormal! o Size/height varies with gender, age • Pituitary "incidentaloma" (cyst, non functioning adenoma) in 15-20% of normal MRs o If it doesn't enhance, cyst is a more likely etiology than microadenoma

Helpful Clues for Common Diagnoses • Pituitary Hyperplasia o Physiologic (e.g., young menstruating or postpartum females) o Pathologic (end-organ failure, neuroendocrine tumors, etc.) • Pituitary Microadenoma o < 10 mm in diameter, may enlarge gland o 70-90% hypointense, enhance more slowly than normal pituitary • Empty Sella o lntrasellar CSF collection ~ pituitary gland flattened against sellar floor o 5-10% prevalence on MR Helpful Clues for less Common Diagnoses • Rathke Cleft Cyst o T1WI: 50% hypo-, 50% hyperintense o T2WI: 70% hyper-, 30% iso-/hypointense • Look for "intracystic nodule" (45-50%) • Craniopharyngioma o Completely intrasellar craniopharyngioma uncommon Helpful Clues for Rare Diagnoses • Lymphoma, metastasis often infiltrate adjacent structures • Venous engorgement ~ bulging gland o Look for intracranial hypotension, dAVF • CNS Siderosis o "Black" pituitary gland on T2* o Found with iron overload states> > SAH • Thalassemia • Hemochromatosis

Rathke Cleft Cyst

Pituitary Microadenoma

I 8 20

=.

Coronal T2WI MR shows a hyperintense intrasellar mass Pre-operative diagnosis was Rathke cleft cyst. An almost entirely cystic m;croadenoma was found at

surgery.

=

Coronal T2WI MR shows hyperintense cystic intJasellar mass found incidentally on MR. This is probably a Rathke cleft cyst or pars intermedia cyst.

INTRASEllAR

lESION

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c: III

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C-

...

O:!

Neurosarcoid

III

(Lefl) Sagittal T1 WI MR

shows a hyperintense inlra~/suprase/Jar mass

=

that displaces the pituitary gland I!::ll. Totally intra sellar craniopharyngioma

without

suprasellar extension is rare. (RighI) Coronal T1 C+ MR shows a slightly enlarged pituitary gland with a thickened infundibulum above ~ in a patient with

=

proven neurosarcoidosis.

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lymphocytic

Hypophysitis (Lefl) Sagittal T1 C+ MR shows an enlarged, uniformly

enhancing

=

pituitary gland

with slight

suprasellar extension. This was proven to be lymphocytic hypophysitis. (Rig"') Coronal T2WI FS MR

shows

II

kissing"

(paramedian)

=

cavernous

ICAs projecting medially into the selJa turcica. Cavernous ICAs normally lie laterally within carotid sulcus of sphenoid bone.

eNS Siderosis (Left) Coronal T1 C+ MR shows a mass lesion diffusely infiltrating/expanding pituitary gland Note

=.

extension

into cavernous

sinus

suggesting more

aggressive pathology. (Rig"') Coronal T2WI MR in 9 year old with long-standing thalassemia major shows profoundly hypoimense pituitary gland caused by iron overload syndrome.

=

I 8 21

c Q

CYSTIC INTRASELlAR MASS

OJ OJ

cr: Iii OJ c 0..

DIFFERENTIAL DIAGNOSIS Common • Empty Sella (ES) • Intracranial Hypertension,

Idiopathic

less Common • Obstructive Hydrocephalus • Rathke Cleft Cyst • Craniopharyngioma • Arachnoid Cyst (AC) • Epidermoid Cyst • Neurocysticercosis Cyst Rare but Important • Pituitary Apoplexy • Saccular Aneurysm (Thrombosed)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Cystic mass originating WITHIN sella vs. intra sellar extension from suprasellar lesion • Intrasellar extension of suprasellar lesion> cystic intrasellar mass Helpful Clues for Common Diagnoses • Empty Sella (ES) o Small crescent of compressed pituitary gland lines bottom of sella turcica o "Primary" ES considered normal variant o "Secondary" = surgery, pituitary infarction • Intracranial Hypertension, Idiopathic o "Pseudotumor cerebri" F> > M o Empty sella ± dilated optic nerve sheaths, small ventricles

Helpful Clues for less Common Diagnoses • Obstructive Hydrocephalus o Anterior recesses of 3rd ventricle enlarge • Herniate inferiorly into sella • If chronic may expand, erode bony sella • Rathke Cleft Cyst o Usually < 1 em; can be giant, erode sella o 45% have "intra cystic nodule" o ± "Claw sign" (enhancing rim of pituitary around nonenhancing cyst) • Craniopharyngioma o Truly intrasellar craniopharyngioma rare o If no Ca++ difficult to distinguish from Rathke cleft cyst • Arachnoid Cyst (AC) o Truly intra sellar AC rare o Usually extension from suprasellar AC • Epidermoid Cyst o Suprasellar location < off-midline • Neurocysticercosis Cyst o Suprasellar cysts - intrasellar Helpful Clues for Rare Diagnoses • Pituitary Apoplexy o Can be life-threatening (secondary to pituitary insufficiency) o Acutely may present as necrotic, rim-enhancing mass • Saccular Aneurysm (Thrombosed) o Medially projecting from cavernous ICA o If thrombosed may appear low signal intensity on Tl C+ scans

Intracranial

I 8 22

Sagittal T1WI MR shows empty sella with herniation of CSF through the diaphragma sellae =.lI flattening the pituitary gland inferiorly against the sellar floorE:l.

Hypertension,

Idiopathic

Axial T2WI MR shows idiopathic intracranial hypertension (pseudolumor cerebri) with "empty sella" =.lI and dilated opUc nerve sheaths 1!:i2.

CYSTIC INTRASEllAR

MASS III

:;, Co

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(Left) Sagiltal T2WI MR shows aqueduclaf stenosis with severe obstructive hydrocephalus. NOle marked enlargement of bony sella 1:1

m

and intrasellar inferior

herniation

of

3rd ventricle ~

(Right) Coronal T1 WI MR shows an intrasellar Ralhke clefl cyst seen here as a CSF-like mass that displaces Ihe piWitary gland inferiorly and laterally around it.

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Arachnoid

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Cyst (AC) (Left) Coronal T2WI MR shows a CSF-like intrasellar mass ~ Surgery disclosed inlrasellar craniopharyngioma

with

only a small suprasellar component. (Right) Sagiltal T1WI MR shows an intra· and suprasellar arachnoid cyst 1:1. The lesion did not restrict on OWl, differentiating

epidermoid

it from

cyst.

(Left) Axial T2WI MR shows a large epidermoid cysl extending into the sella and suprasellar subarachnoid

'-=

space from the quadrigeminal and ambient cisterns 1:1. (Right) Sagiltal T7 C+ MR shows suprasellar

'-=

racemose NCC CYSlS extending into sella turcica E!ll (fattening pituitary gland against sellar (foor ffi

I 8 23

SUPRASEllAR MASS, GENERAL ro
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DIFFERENTIAL DIAGNOSIS Common • Pituitary Macroadenoma • Meningioma • Saccular Aneurysm • Craniopharyngioma • Pilocytic Astrocytoma less Common • Dilated Third Ventricle • Arachnoid Cyst • Neurocysticercosis • Rathke Cleft Cyst • Neurosarcoid • Langerhans Cell Histiocytosis • Germinoma • Dermoid Cyst • Lipoma Rare but Important • Lymphocytic Hypophysitis • Tuber Cinereum Hamartoma • Epidermoid Cyst • Pituicytoma • Diffuse Astrocytoma, Low Grade • Pilomyxoid Astrocytoma • Ectopic Neurohypophysis • Metastasis • Lymphoma, Metastatic • Leukemia • Cavernous Malformation • Tuberculoma • Pituitary Abscess

ESSENTIAL INFORMATION Key Differential • Is mass arising • Does it mostly • Is patient adult

I 8 24

Diagnosis Issues from pituitary or other site? involve infundibular stalk? or child?

Helpful Clues for Common Diagnoses • Most common diagnoses ("big five") account for> 75% of all suprasellar masses • Pituitary Macroadenoma o Most common of all suprasellar masses = suprasellar extension of macroadenoma o Gland, mass can't be separated o Cystic, hemorrhagic changes common o Mass is the pituitary gland • Meningioma o Arises from diaphragma sellae

Thin black line (diaphragma sellae) separates mass from pituitary o "Dural tail sign" • Not pathognomonic but highly suggestive • Signal intensity following contrast usually> tumor itself • Saccular Aneurysm o Most arise from circle of Willis o Are usually slightly eccentric, not midline o Signal intensity may be mixed • Partial/complete thrombosis common • Complex/disturbed flow may cause spin dephasing • Look for phase artifact o Occasionally fusiform aneurysm/ectasia of basilar artery may project into suprasellar cistern • Craniopharyngioma o Most common suprasellar mass in child o Adamantinomatous subtype o Imaging • 90% Ca++, 90% cystic • 90% enhance (rim ± nodule) o Second peak in middle-aged adults • Papillary subtype • Solid> cystic; Ca++ uncommon • Pilocytic Astrocytoma o Second most common suprasellar mass in children (rare in adults) o Hypothalamus/optic pathways o Pilocytic > > pilomyxoid type (see below) o

Helpful Clues for less Common Diagnoses • Dilated Third Ventricle o Most common "cystic" suprasellar mass o Third ventricle enlarged secondary to obstructive hydrocephalus • Arachnoid Cyst o Elevates, displaces third ventricle • Neurocysticercosis o Suprasellar cistern, sylvian fissures common sites o Variable size cysts, enhancement o Reactive meningeal changes may be striking (e.g., stalk thickening, vascular encasement) • Rathke Cleft Cyst o Look for intracystic nodule o Pituitary displaced by mass

• Neurosarcoid o

Thickened stalk may be only sign

SUPRASELLAR

MASS, GENERAL

C/l

~ c:

• •

• •

o Look for dural-based masses Langerhans Cell Histiocytosis o Thickened stalk, child with Dl Germinoma o Stalk ± gland o Can be only site but look for pineal mass Dermoid Cyst o Fat-like ± droplets (ruptured) Lipoma o Fatty mass stuck on hypothalamus o Use fat-saturated Tl WI

•

•

•

Helpful Clues for Rare Diagnoses

• Lymphocytic Hypophysitis o Thick, nontapering stalk ± pituitary mass o Diabetes insipidus common o Often occurs in peripartum females • Tuber Cinereum Hamartoma o Clinical presentation helpful (gelastic seizures; male with precocious puberty) o Can be "collar button" or "sessile" o Between infundibulum (anteriorly), mammillary bodies (posteriorly) o Signal intensity like cortex o Does not enhance • Pituicytoma o Low grade (WHO I) glial neoplasm of infundibulum or neurohypophysis oM> F, most patients 40-60 years o Hypopituitarism, visual disturbances o Well-demarcated, homogeneously enhancing infundibular mass • Diffuse Astrocytoma, Low Grade

• •

•

•

o Infiltrating mass difficult to distinguish from pilocytic astrocytoma (PA) Pilomyxoid Astrocytoma o Rare, more aggressive PA variant o Infant/young child with bulky H-shaped suprasellar mass o Often hemorrhages (PA, low grade do not) Metastasis o Gland ± stalk mass in patient with known primary Lymphoma, Metastatic o Destructive, infiltrative mass engulfs gland, stalk Leukemia o Gland/stalk + sinus mass clues Cavernous Malformation o "Popcorn ball" mass o Third ventricle, optic chiasm rare sites Tuberculoma o TB meningitis> > frank tuberculoma in suprasellar cistern o Focal mass wiring enhancement common o If caseating, mass is hypointense on T2WI o If non caseating, mass generally hyperintense on T2WI Pituitary Abscess o Very rare but potentially life-threatening o May resemble pituitary apoplexy at imaging • Cystic-appearing intrasellar mass with suprasellar extension • Hypodense on NECT • Hyperintense on T2WI • Rim-enhancing

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Pituitary Macroadenoma

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Sagittal T 1 C+ FS MR shows a pituitary macroadenoma The pituitary gland cannot be seen separate from U,e mass. The mass is the gland, which is diffusely enlarged by the tumor.

Sagittal T7 C+ MR shows a classic suprasellar meningioma arising from the diaphragma sellae Idl which clearly separates the mass from the normal pituitary below Ell. Note dural "tails"

=.

I 8 25

c

SUPRASELLAR

Q

MASS,

GENERAL

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Saccular Aneurysm (Left) Sagittal T7 WI MR shows a farge, mixed signal intensity, suprasellar mass Laminated clot of different ages gives mass an

=.

"onion skin" appearance.

Note residual patent lumen 81. (Right) Sagillal T7WI MR shows a craniopharyngioma 81 with variable T7 shortening within the multilocu/aled

cystic

components. The pituitary gland PJ:J:l is clearly distinct from the mass .

Pilocytic Astrocytoma

Dilated Third Ventricle

(Left) Sagiltal T7 C+ MR shows a large pi/ocytic astrocytoma, seen here as a lobulated inhomogeneously enhandng suprasellar mass Pituitary 81 is clearly separate from the mass. (Right) Sagittal T7 C+ MR

=.

shows obstructive hydrocephalus with a dilated 3rd ventricle 81. The large anterior recesses compress and displace the infundibular stalk and hypothalamus inferiorly.

=

Arachnoid (Left) Sagittal T7 WI MR

shows a class;c suprasellar arachnoid cyst. Note that the CSF-Iike suprasellar mass

=

elevates the 3rd ventricle and displaces the infundibular stalk anteriorly 81. (Right) Sagiltal T7 WI MR in a patient with known neurocysticercosis shows a markedly thickened inFundibulum e.'I as well as multiple supra- and intrasellar cysts 8asal cistern lesions are common in NCe.

=.

I 8 26

Cyst

Neurocysticercosis

SUPRASELLAR

Rathke Cleft Cyst

MASS, GENERAL

Neurosarcoid (Lefl) Sagittal TI WI MR shows a typical Rathke cle(t cyst. Note that the well-delineated hype,intense sup,asellar mass I:] is clearly distinct from the pituitary gland below PJ:ll. (RighI) Sagillal T1 C+ MR in a patient with known systemic sarcoidosis and diabetes insipidus shows a thickened, enhancing

infundibulum

=.

This was the only intracranial finding.

(Leh) Sagillal T1 C+ MR in a child with known histiocytosis and diabetes insipidus shows a strongly enhancing mass involving the infundibular stalk and hypothalamus 1:]. (RighI) Sagillal T1 C+ MR shows a germinoma with sellar 81 and suprasellar involvement. The infundibular stalk is markedly thickened, while the pineal gland is normal.

=

(Lefl) Sagillal T1 C+ MR shows a ruptured dermoid cyst 81 with a large

supra/parase/Jar component. Note multiple high signal intensity droplets I:] scallered throughout the subarachnoid space. (RighI) Sagillal T1WI MR shows a hypothalamic lipoma seen here as a lobulated hyperintense mass above and behind the sella. This

=-

was an incidental

finding in

an asymptomatic

patient.

I 8 27

c

SUPRASELLAR

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MASS,

GENERAL

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Tuber Cinereum

Hamartoma

(Left) Sagittal T1 C+ FS MR in a 19 year old pregnant woman shows a uniformly enhancing sellar/suprasellar mass m. Note reactive dural thickening 81. Lymphocytic hypophysitis was found at surgery. (Rig!Jt) Sagittal T 1 WI MR shows a classic luber cinereum hamartoma The hamartoma looks like a "collar button" of gray

m.

matter interposed between the infundibulum and mammillary bodies.

(Left) Axial T1 WI MR shows an epidermoid cyst The lobulated CSF-like mass extends into the suprasellar !:ill and quadrigeminal 81 cisterns. (Right) Sagitlal T1 C+ MR shows a pituicytoma,

=.

seen here as a large solid infundibular mass !:ill with mild mass effect on the optic chiasm and anterior 3rd ventricle.

Diffuse Astrocytoma, (Left) Coronal T1 C+ MR shows a rounded enhancing mass separate from pituitary gland below Ell displaced optic chiasm above !:ill. Grade 11fibrillary

=

astrocytoma

=.

I 8 28

of

hypothalamus (possibly infundibular stalk) was found at surgery. (Right) Coronal T2WI MR in a 21 year old man with sudden headache and visual problems shows a hemorrhagic suprasellar mass Initial diagnosis was pi/oeytie astrocytoma. Final diagnosis was PMA.

Low Grade

Pilomyxoid

Astrocytoma

SUPRASELLAR

en ,.-

MASS, GENERAL

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Metastasis

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(Left) Sagittal T7WI MR shows posterior pituitary ectopia, seen here as a hyperintense focus !:>J along the upper infundibulum. Note a small pituitary gland Ell with an absent "bright spot". (Right) Sagittal T7 C+ MR shows a metastasis enlarging the infundibulum, extending into the pituitary gland ~ This was the only intracranial manifestation of metastatic lung carcinoma.

=

lymphoma,

Metastatic

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en !E.

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x iii en

CD Q)

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leukemia (Left) Sagillal T7 WI MR shows a destructive, diffusely infiltrating mass with signiHcant infra-, 5upra- and

relrose/Jar extension

=.

Lesion enhanced strongly. quite uniformly on T7 C+ scans (not shown) and demonstrated "dural tail sign" Ell. (Right) Coronal CECT shows opacification of sphenoid sinus Other images

(not shown)

disclosed lobulated

mucosal-based

masses in the

maxillary/ethmoid sinuses. Note rounded, thickened infundibular stalk

=.

Tuberculoma (Left) Sagillal T7WI MR

shows suprasellar "popcorn ball" of mixed signal intensity ~

appearing

to arise within

3rd ventricle. Type 2 cavernous

malformation

was

diagnosed. (Right) Axial CECT shows a tuberculoma in the suprasellar cistern, seen here as a ring-enhancing mass. Note accompanying findings of TB meningitis Ell. (Courtesy S. Candy, MO).

=

I 8 29

c .Q

SUPRASEllAR MASSES, PEDIATRIC

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DIFFERENTIAL DIAGNOSIS Common • Pilocytic Astrocytoma • Craniopharyngioma • Pituitary Hyperplasia (Physiologic) • Hydrocephalus less Common • Germinoma • Tuber Cinereum Hamartoma • Arachnoid Cyst • Langerhans Cell Histiocytosis • Pituitary Stalk Anomalies • Teratoma Rare but Important • Lipoma • Pituitary Macroadenoma • Dermoid Cyst • Leukemia • Pilomyxoid Astrocytoma • Saccular Aneurysm • Retinoblastoma (Trilateral) • Lymphocytic Hypophysitis • Lymphoma, Primary CNS • Rathke Cleft Cyst

ESSENTIAL INFORMATION

I 8 30

Key Differential Diagnosis Issues • Is mass extra- or intra-axial? • Extra-axial masses arise from pituitary/infundibulum, meninges, vessels o If extra-axial mass appears to arise from pituitary/infundibulum, determine origin of mass as precisely as possible • Pituitary gland: Think physiologic hyperplasia, hypophysitis, macroadenoma (rare in children) • Infundibular stalk: Germinoma, histiocytosis; stalk anomalies, lymphoma, leukemia (rare) o Nonpituitary extra-axial masses (normal pituitary gland can usually be identified inferior to lesion) • Craniopharyngioma • Hydrocephalus • Arachnoid cyst • Saccular aneurysm • Intra-ax.ial masses arise from chiasm/hypothalamus/3rd ventricle

Optic chiasm/hypothalamus: Pilocytic or pilomyxoid astrocytoma, tuber cinereum hamartoma, lipoma o Third ventricle: Hydrocephalus> > neoplasm • T1 hyperintense suprasellar mass in child? Think craniopharyngioma, lipoma, dermoid, posterior pituitary ectopia o

Helpful Clues for Common Diagnoses • Pilocytic Astrocytoma o Most PAs occur in children 5-15 years old o Enlarged optic nerve/chiasm/tract o Usually solid, iso-/hypointense on T1 WI; hyperintense on T2WI, FLAIR o Variable enhancement (none to intense) o If large, bulky H-shaped mass in infant, may be pilomyxoid variant • Craniopharyngioma o 90% Ca++ (globular, rim) 090% cystic (may have multiple) o 90% enhance (rim, nodule) o Density/signal intensity within cysts/locules varies with content • Pituitary Hyperplasia (Physiologic) o Up to 10 mm height, convex superior margin in young menstruating females o "Macroadenoma-appearing" mass in child? • May be hyperplasia, not tumor (especially prepubescent male)! • Hydrocephalus o Enlarged 3rd ventricle (aqueductal stenosis, obstructive hydrocephalus) o Anterior recesses protrude inferiorly o May enlarge bony sella over time Helpful Clues for less Common Diagnoses • Germinoma o 50-60% involve pituitary gland/stalk o Often presents with diabetes insipidus (DI) • Tuber Cinereum Hamartoma o Isosexual precocious puberty> gelastic seizures o Pedunculated ("collar button") or sessile mass between infundibular stalk, mamillary bodies • Can be tiny (1-2 mm) or giant (3-5 em) • Isointense with gray matter (occasionally slightly hyperintense on FLAIR) • Doesn't enhance • Arachnoid Cyst o 10% suprasellar o Sharply marginated CSF-like cyst

SUPRASEllAR MASSES, PEDIATRIC Sagittal Tl- or T2WI shows 3rd ventricle elevated, compressed over cyst a Suppresses on FLAIR,DWI negative • Langerhans Cell Histiocytosis a Child usually < 2 years old • May have central DI a 10% of LCH cases involve stalk, pituitary gland ± hypothalamus • Rare: Choroid plexus, leptomeninges, cerebellar WM, brain parenchyma a Look for solitary/multiple lytic skull lesions with "beveled edges" • Pituitary Stalk Anomalies a Posterior pituitary ectopia • Short stature ± endocrine deficiencies • Posterior pituitary "bright spot" missing • Mislocated along tuber cinereum • Stalk small/absent a Duplicated pituitary gland/stalk • Endocrinologically normal • ± Midline facial anomalies • Tuber cinereum/mamillary bodies fused • Teratoma a Optic chiasm> pineal a Ca++, cysts, soft tissue, fat a

Helpful Clues for Rare Diagnoses • Lipoma a Fatty hypothalamic mass • Pituitary Macroadenoma a "Figure-of-eight" pituitary mass a Gland can't be separated from mass • Dermoid Cyst a Fat-like mass ± droplets in CSF

• •

•

• •

•

•

• Fat suppression sequences confirm 020% Ca++ Leukelnia a Rare; look for other lesions (sinuses, dura) Pilomyxoid Astrocytoma a Rare variant of PA a Large, bulky suprasellar mass in infant a May hemorrhage (rare in PA) Saccular Aneurysm a Rare in children « 2% of all saccular aneurysms occur in pediatric age group) a When occur, often large/bizarre a Thrombus common a Look for residual patent lumen, phase artifact Retinoblastoma (Trilateral) a Third tumor in pineal or suprasellar region Lymphocytic Hypophysitis a Adolescent> child a May cause DI a Can mimic macroadenoma, pituitary apoplexy Lymphoma, Primary CNS a Rare in children a Can mimic hypophysitis, germinoma, LCH Rathke Cleft Cyst a Rare in children a Cyst in/above pituitary, separate from stalk a Rarely calcifies, does not enhance ("claw" of enhancing pituitary tissue may surround mass) a Intracystic nodule virtually pa thognomonic

III

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C. OJ

., III

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iii Vl

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CD OJ

Pilocytic Astrocytoma

Coronal T7 C+ MR shows chiasmatic glioma. prechiasmaUc optic nerves are expanded surrounded by enhancing tumor.

The and

Coronal pilocytic

T7 c+ MR shows a very large suprasellar astrocytoma. This solid and cystic mass

I 8

involves the suprasellar cistern, the chiasm, the hypothalamus

and protrudes into the 3rd ventricle.

31

c

SUPRASELLAR

.Q

MASSES,

PEDIATRIC

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a::

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co

(Left) Sagittal T1 WI MR shows typical cysts of varying signal intensity in the suprasellar cistern~ herniating into the 3rd ventricle. There is enlargement of the bony

Qi

sella and erosion of the

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)(

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dorsum sella =:1. (Right) Coronal T2WI MR shows calcification allhe base of the lesion 81.

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c I'll

Germinoma (Left) Sagittal T1 C+ MR shows large pituitary gland =:1 projecting above shallow pituitary fossa following prolonged shunting. Note associated thickened calvarium 81. (Right) Sagittal T2WI MR shows typical synchronous suprasellar =:I, pineallaJ masses in teen who presented with signs of t intracranial

pressure.

Note

increased signal in body of corpus callosum

at site of

hippocampal commissure disruption c;. caused by acute hydrocephalus.

(Leh) Sagittal T1 C+ MR in

the same patient shows inhomogeneous enhancement II1~LThe suprasellar mass perches on dorsum sella; the pineal obstructs the aqueduct. (Right) Sagittal T1 C+ MR shows a large nonenhancing pedunculated mass =:1 extending from tuber cinereum between mamillary bodies and infundibular stalk in a child with ge/astic seizures.

I 8 32

SUPRASELLAR

MASSES,

,...

PEDIATRIC

C/l

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.,

III

Tuber Cinereum

Hamartoma

Arachnoid

CIl

Cyst (Left) Axial FLAIR MR shows mildly increased signal intensity within the hamarlOma Unlike small hamartomas, which foJ/ow gray maLLersignal on T2 and FLAIR sequences, large hamarlOmas may be slightly brighter on FLAIR and T2 than gray matter. (Right) Coronal T2WI MR shows erosion of the dorsum sella, upward displacement of the hypothalamus, and extension inlO the right middle cranial fossa caused by suprasellar arachnoid cyst

=.

=.

Langerhans Cell Histiocytosis

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Pituitary Stalk Anomalies (Lefl) Sagittal T1 C+ MR in a teen shows nodular thickening of infundibular recess ~, Additionally, there is a tiny pars intermedia cyst e.1. Note upwardly convex pituitary gland (normal physiologic hyperplasia) (Right) Coronal T1WI MR shows thickening of the tuber cinereum {tubomammillary fusion) in a child with 2 pituitary glands ~ due 10 maternal genetics. Both glands are bright on T1 WI images in the premature

=,

=

newborn.

Teratoma (Left) SagiLLalT1 WI MR shows bright fat with a central focus of calcification There is a soft tissue mass ~ in the region of the tuber cinereum in this child who had multiple other congenital anomalies. (Right) Axial FLAIR MR in the same patient shows heterogeneous suprasellar teralOma ffi metopic synostosis dehiscent tentorium Ea. A small nodule of

=.

=

perivenlricular

heterotopia

also seen in wall of right temporal horn

=,

is

I 8 33

c Q

SUPRASELLAR MASSES, PEDIATRIC

OJ Q)

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ro

(Left) Axial T1 WI MR shows a multilobed lipoma l:ll in the suprasellar cistern. (Right) Sagittal T1 C+ FS MR in the same patient shows loss of signal in lipoma l:ll

-a>

{ollowing

~ CO

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fat saturation.

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Pituitary Macroadenoma

Pituitary Macroadenoma

(Left) Sagittal T1 WI MR shows a large bilobed sellar and suprasellar !:i12 macroadenoma in a teenager with acromegaly. Note also the enlarged frontal sinuses 81. (Right) Coronal T1 C+ MR shows a fairly homogeneously enhancing macroadenoma 81 that abuts the cavernous sinus in the same acromegaJ;c teen. Note thickened scalp l:ll.

Pilomyxoid (Left) Sagillal T2WI MR shows a large, very hyperintense, suprasellar pilomyxoid astrocytoma that displaces the mesencephalon posteriorly. (Right) Sagillal T2WI FS MR in a newborn shows a large, lobular, thrombosing, suprasellar saccular aneurysm lID.

I 8 34

Astrocytoma

Saccular Aneurysm

SUPRASEllAR

MASSES, PEDIATRIC III

::l

Co

., OJ III

(Left) Axial MRA shows obliteration of the right distal internal carotid artery and faint increased signal in the posterior ~ aspect of the thrombosing aneurysm. (Right) Coronal T2WI MR shows a large low signal suprasellar mass ~ that abuts the hypothalamus. Patient had ocular retinoblastoma.

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Retinoblastoma

(Trilateral) (Left) Coronal T1 C+ MR in the same patient shows intense, uniform enhancement. Note bilate,al cavernous sinus invasion (Right) Sagittal T1 C+ MR in a pregnant teenager who developed acute onset of vision problems in lale 3rd trimester shows large enhancing mass with reactive dural thickening 61. Pre-operative diagnosis was macroadenoma.

rs

=.

=

Rathke Cleft Cyst (Left) Sagittal T1 C+ MR shows thickening ~ and subtle enhancement of the infundibular stalk, chiasm, and tuber cinereum. (Right) Coronal T2WI MR shows a well-delineated suprasellar cyst The pituitary gland and stalk are not seen, and

=.

there was no calcification

on

high resolution NECT.

I 8 35

SUPRASEllAR CYSTIC MASS

DIFFERENTIAL DIAGNOSIS Common • Enlarged Third Ventricle o Obstructive Hydrocephalus o Aqueductal Stenosis • Arachnoid Cyst • Craniopharyngioma • Neurocysticercosis (NCC) t:

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aI

"t: III

less Common • Rathke Cleft Cyst • Dermoid Cyst • Epidermoid Cyst • Enlarged Perivascular Spaces (PVSs) Rare but Important • Pituitary Macroadenoma • Pituitary Apoplexy • Astrocytoma o Pilocytic Astrocytoma o Pilomyxoid Astrocytoma • Ependymal Cyst • Saccular Aneurysm

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Where does the mass originate? o Third ventricle: Think hydrocephalus> intraventricular cystic mass (ependymal cyst, craniopharyngioma) o Suprasellar cistern: Arachnoid, other congenital/infectious cysts o Pituitary gland/sella turcica: Necrotic/cystic neoplasm o Brain parenchyma: Enlarged perivascular spaces, cystic/low density neoplasm

I 8 36

Helpful Clues for Common Diagnoses • Enlarged Third Ventricle o CSF density/signal intensity o No enhancement (unless infection, neoplasm) o Obstructive Hydrocephalus • Can be intra- or extra-ventricular (noncommunicating or communicating) • If acute, periventricular "halo" of transependymal CSF • "Cystic mass" = dilated 3rd ventricle o Aqueductal Stenosis • t Lateral, 3rd ventricles • Normal 4th ventricle

• Usually longstanding, "compensated" so no transependymal CSF • Arachnoid Cyst o 10% of ACs suprasellar (SSAC) o Sharply marginated CSF density/signal intensity mass • Suppresses on FLAIR • Does not restrict on DWI o 3rd ventricle elevated, displaced over AC • Displaces temporal lobes laterally • Displaces midbrain, pons posteriorly • Infundibular stalk typically displaced anteriorly • "Mickey mouse ears" on coronal = cyst + lateral ventricles o If large, may also cause obstructive hydrocephalus • Craniopharyngioma o 90% of childhood craniopharyngiomas cystic • Cyst fluid hyperdense/intense to CSF o 90% have some Ca++ (globular or rim) o 90% enhance (rim, nodular) o Suprasellar cistern> > within 3rd ventricle • Neurocysticercosis (NCC) o Look for "clusters" of cysts in subarachnoid cisterns ("racemose" CC) o Look for cyst + scolex o FLAIRbest sequence to detect (cyst fluid doesn't suppress completely) Helpful Clues for less Common Diagnoses • Rathke Cleft Cyst o 60% purely suprasellar or intra sellar with suprasellar extension o Variable density/signal intensity • Usually t compared to CSF • 10% calcify (curvilinear, in cyst wall) o Look for • Intracystic nodule (45%) • "Claw" of compressed, enhancing pituitary displaced around cyst • Dermoid Cyst o Most common site = sellar/parasellar, frontonasal o Fat densi ty/signal intensity o 20% have capsular Ca++ o Look for evidence of rupture • Fat droplets in subarachnoid spaces • Fat-fluid levels in ventricles • Chemical shift artifact in frequency encoding direction

SUPRASELLAR

,...

CYSTIC MASS

C/l

c

• Epidermoid Cyst o Rare in suprasellar cistern o Lobulated, insinuating growth pattern 0> 95% hypodense (similar to CSF) • FLAIR,DWI best to distinguish epidermoid from AC, enlarged 3rd ventricle • Epidermoid doesn't suppress completely, restricts on DWI • Enlarged Perivascular Spaces (PVSs) o Usually variable-sized "clusters" o Off-midline (basal ganglia) o Round or ovoid (basal ganglia), linear (white matter) o Like CSF on all sequences (contain interstitial fluid) • Suppresses completely on FLAIR • Does not restrict on DWI Helpful Clues for Rare Diagnoses • Pituitary Macroadenoma o Solid ± intra- or extra tumoral cysts • Extratumoral cysts may be trapped/enlarged PVSs or arachnoid cysts • Cysts often hyperdense/intense compared to CSF o Solid> rim enhancement • Pituitary Apoplexy o Rare; may be life-threatening (severe panhypopituitarism) o Necrotic pituitary with little/no enhancement (may show rim) o Hemorrhage may bloom on T2* (GRE, SWI)

=-

Sagillal T2WI MR shows EVOH wilh markedly enlarged laleral 3rd El and 4lh I!:1\'l ventricles. A CSF suprasellar mass caused by an enlarged 3rd venlficle was diagnosed.

Compression/edema of hypothalamus, optic chiasm/tracts may cause hyperintensity on T2WI o Restricts on DWI o Markedly hypointense on ADC • Astrocytoma o Pilocytic > > pilomyxoid astrocytoma o Most suprasellar astrocytomas are solid, not grossly cystic • Ependymal Cyst o Rare; 3rd ventricle least common site o Round/ovoid; CSF-like • Saccular Aneurysm o Aneurysms may be associated with true perianeurysmal cysts • Obstructed perivascular spaces posited as etiology o Partly or completely thrombosed may have "cystic"-appearing foci within clot • Rare • Acute thrombosis can present with panhypopituitarism, SAH o Imaging can mimic necrotic adenoma • Hypodense center, iso-/hyperintense rim on TlWI • Look for mixed age laminated clot • "Blooms" on GRE • Rim may enhance o

Sagillal T2WI MR shows massively enlarged 3rd SlI and laleral ventricles, an enlarged "funnel-shaped" aqueducl and a medial atrial diverticulum R> compressing the 4th ventricle

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I 8 37

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CYSTIC MASS

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Arachnoid Cyst (Left) Sagiltal T2WI FS MR shows a lobulated, sharply marginated, CSF-like, suprasellar cyst =:I extending into the sella 8l elevating the 3rd ventricle ICR and causing obstruclive hydrocephalus. (Right) Coronal T2WI FS MR in an 8 year old child with delayed growth shows a hyperintense suprasellar mass =:I that slightly compresses and displaces the pituitary gland SI toward the lelt.

Rathke Cleft Cyst (Left) Coronal T2WI MR shows a suprasellar cystic mass and a moderate

=

compensated hydrocephalus. Another cyst is present in the right Meckel cave 81 in this patient with racemose NCe. (Right) Sagittal T1 C+ MR shows an intra- and suprasellar cyst that does not enhance. Note the displaced pituitary gland and infundibular stalk =:I form a "claw" around the lesion.

Dermoid Cyst (Left) Axial NECT shows a large, mixed density suprasellar and subfrontal mass =:I. Low density "droplets" that resemble fat are seen in the adjacent sylvian fissure E1 in this patient with a ruptured dermoid. (Right) Axial T2WI MR shows an epidermoid cyst in the suprasellar cistern, widening the interpeduncular fossa and extending into the ambient and quadrigeminal

.:=

cisterns.

I 8 38

SUPRASELLAR

en

CYSTIC MASS

c: "

Ql

:l

Co

..• lJl Ql

(Left) Sagillal TI WI MR in a 1S year old with headaches shows multiple CSF-like cysts in the hypothalamus, thalamus, and midbrain ~ that bulge into the suprasellar subarachnoid space [;8 (Right) Axial TI C+ MR shows 2 neoplasm-associated cysts: A large trapped perivascular space 81 caused by a pituitary

(f)

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macroadenoma

and a small imrawmoraJ cyst

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within the adenoma.

CD <0

o· :l

(LeFt) Axial CECT shows pituitary apoplexy caused by

a

necrotic

pituitary

I::l.

macroadenoma

appearance

Imaging

resembles

a

thrombosed aneurysm. (Right) Sagillal T2WI MR shows a very hyperintense suprasellar mass, almost as bright as CSF A thin rim of normal-looking brain borders the mass ffi indicating its

intra-axial origin.

(Left) Sagillal STIR MR with a close-up view shows a large cystic lesion within the 3rd ventricle The lateral ventricles 81 are markedly enlarged, but the 4th ventricle ~ is normal. (Right) Axial TlWI MR shows a partially thrombosed

=.

saccular aneurysm

=. Part

of the clot is very hypodense P!:J and is seen here as a mass in the posterior

suprasellar cistern.

I 8 39

c

CALCIFIED SUPRASELLAR MASS

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DIFFERENTIAL DIAGNOSIS Common • Atherosclerosis, Intracranial • Craniopharyngioma • Meningioma • Aneurysm o Saccular Aneurysm o Fusiform Aneurysm, ASVD Less Common • Neurocysticercosis • Pilocytic Astrocytoma • Dermoid Cyst Rare but Important • Pituitary Macroadenoma • Tuberculosis • Chondroid Tumor

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Is Ca++ curvilinear, punctate, globular, etc.? • Does lesion enhance? Helpful Clues for Common Diagnoses • Atherosclerosis, Intracranial o Curvilinear Ca++ o Usually bilateral o Often multifocal o Older patients • Craniopharyngioma o Globular, punctate, &/or ring Ca++ o Younger patients (older adult tumors more often solid, Ca++ less frequent)

Atherosclerosis,

I 8 40

=

• Meningioma o Psammomatous (sand-like) Ca++ o Solid> rim enhancement o Middle-aged, older patients (unless NF2) • Aneurysm o Saccular Aneurysm • Calcification less common than with fusiform aneurysm, ASVD • Curvilinear (peripheral arcs, rings) pattern o Fusiform Aneurysm, ASVD • Linear ± rim Ca++ • Ca++ often present in other vessels Helpful Clues for Less Common Diagnoses • Neurocysticercosis o Nodular calcified stage o Usually parenchymal> > cisternal Ca++ • Pilocytic Astrocytoma o Common in children, young adults o Ca++ uncommon in hypothalamic PA • Dermoid Cyst o 20% have capsular Ca++ o Contain lipid o Look for evidence of rupture (fatty droplets in subarachnoid spaces, cisterns) o No enhancement unless chemical meningitis Helpful Clues for Rare Diagnoses • Only 1-2% of macroadenomas calcify • TB, healing/healed granulomatous infections cause parenchymal> > cisternal Ca++ • Chondromas, enchondromas arise from central base of skull

Intracranial

Axial NEeT shows a fusiform, parUally calcified mass in the suprasellar cistern that represents an ectaUc~ supraclinoid, internal carotid artery with calcified

Axial NEeT shows a cystic suprasellar mass with globular and rim calcificaUons Note fluid-fluid level within one of the cysts m. This is an example of classic

atherosclerotic plaque.

craniopharyngioma.

=.

CALCIFIED SUPRASELLAR MASS

,...

VI C Ql

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Co

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OJ Ql

(Left) Axial NECT shows a hyperdense suprasellar mass with Focal calciFications m in this patient with cfassic meningioma arising from the central skull base. (Right) Axial NECT shows a huge, well-delineated hyperdense suprasellar mass with rim calciFications The diagnosis: Giant mostly thrombosed, saccular aneurysm.

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Fusiform Aneurysm, ASVD

Neurocysticercosis (Left) Axial NECT shows a hype,dense FusiFormbasi/ar artery aneurysm 81 and calcified fusiform aneurysmal ectasias of both internal carotid arteries (Right) Axial NECT shows a suprasellar, ambient cistern Ca++ in this patient with racemose Nee, multiple cysts. (Courtesy E. Bravo, MO).

=.

=

Dermoid Cyst (Left) Axial NECT shows a low density suprasellar mass with rim and globular calciFication 81. Biopsy disclosed pilomyxoid variant of pi/oeytie astrocytoma. (Right) Axial NECT shows a large hypodense calciFied suprasellar mass aD. Note fat density droplets 81 in subarachnoid space. This is a ruptured dermoid cyst.

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I 8 41

c

ENHANCING SUPRASElLAR MASS

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DIFFERENTIAL DIAGNOSIS Common • Pituitary Macroadenoma • Meningioma • Saccular Aneurysm • Craniopharyngioma • Pilocytic Astrocytoma Less Common • Diffuse Astrocytoma, Low Grade • Neurosarcoid • Langerhans Cell Histiocytosis • Germinoma • Lymphocytic Hypophysitis Rare but Important • Metastasis • Lymphoma • Leukemia

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Effect of age on differential diagnosis important • Common lesions ("big five") account for > 75% of all suprasellar masses • Most other lesions < 1-2% each • Differential diagnosis narrows if mass confined to infundibulum Helpful Clues for Common Diagnoses • Macroadenoma vs. Meningioma o Macroadenoma: Gland can't be identified separate from mass

Meningioma: Mass distinct from gland (hypointense diaphragma sellae separates mass above from pituitary gland below) • Saccular Aneurysm o Coronal plane helpful in distinguishing aneurysm from normal pituitary o Look for phase artifact, "flow void" on MR • Craniopharyngioma o 90% Ca++, 90% cystic, 90% enhance o Papillary variant (more common in adults) may be solid, noncalcified, enhances strongly • Pilocytic Astrocytoma o More common in children o Expands hypothalamus, optic chiasm, may extend into optic nerves/tracts o Variable enhancement o Pilomyxoid variant • Infant> child • Aggressive behavior • Large, bulky tumor with lateral extension to temporal lobe common • Hemorrhage in 20-25% o

Helpful Clues for Less Common Diagnoses • Histiocytosis, germinoma in children/young adults • eurosarcoid in older patients Helpful Clues for Rare Diagnoses • Solitary metastasis to gland/stalk rare • Lymphoma, leukemia usually with systemic disease

Pituitary Macroadenoma

I 8

Coronal T1 C + M R shows inhomogeneously enhancing

intra- and suprasellar mass

=. Pituitary gland can't be

found separate from and indeed IS the mass.

42

Coronal TI c+ FS MR shows suprasellar enhancing mass 81 separated from normal pituitary gland below P:!.':l by thin black line of diaphragma sellae

=.

ENHANCING

SUPRASEllAR

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MASS

c: III

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(Left) Axial T1 C+ MR shows suprasellar enhandng mass

=

with prominent phase artifact E!llI caused by large basilar lip aneurysm with

slow intralumcnal

flow.

(Right) Coronal T1 C+ MR in a child shows

intra·/supraseJlar mass. Apical

nonenhancing

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portion

is surrounded by thin enhancing rim PJ:;}lI. Solid

portion enhances strongly

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but heterogeneously

(Left) Axial T1 C+ FS MR shows enhancing suprasellar mass involving optic chiasm hypothalamus E!llI with

=

pial enhancement

along

inFerior fronta/lobe~.

Lesion a/so involved optic nerve. (Right) Sagittal T1 C+ MR in child with diabetes insipidus, known LCH, shows thickened enhancing pituitary stalk mass extending into hypothalamus.

=

(Left) Coronal T1 C+ FS MR in 22 year old man with

diabetes insipidus shows hydrocephalus,

enhancing

sellar/suprasellar mass. Germinoma commonly presents with 01; macroadenoma oflen has visual defects. (Right) Coronal T1 C+ FS MR in a 19

year

old pregnant

woman

with acute vision problems shows enhancing

intra-/suprasellar mass

=.

Pre-operative diagnosis was macroadenoma, but the patient's history is more consistent with LH.

I 8 43

c

ABSENT/THIN INFUNDIBULAR STALK

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DIFFERENTIAL DIAGNOSIS less Common • Pituitary Stalk Transection, Post-Traumatic • Pituitary Stalk Transection, Post-Surgical • Pituitary Stalk Anomalies • Septa-Optic Dysplasia (SOD) • Holoprosencephaly Rare but Important • Neurocysticercosis • Meningitis

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ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Is small/absent stalk congenital or acquired? • Clinical information extremely helpful o History of trauma or surgery? o Hypothalamic/pituitary axis dysfunction? o Short stature? Helpful Clues for less Common Diagnoses • Pituitary Stalk Transection, Post-Traumatic o Usually occurs following motor vehicle accident o Can occur with closed head injury o May occur with or without accompanying basilar skull fracture • Pituitary Stalk Transection, Post-Surgical o Children: Most common after craniopharyngioma resection o Adults: Most common after macroadenoma resection

• Pituitary Stalk Anomalies o Most common = ectopic posterior pituitary • Posterior pituitary "bright spot" in hypothalamus • Stalk thin or absent • Shallow sella, small pituitary o Less common = duplicated stalk • Two separate, thinned stalks present • Infundibular recess of 3rd ventricle widened, interposed between duplicated stalks • Tuber cinereum thickened, often fused with mammary bodies • Septo-Optic Dysplasia (SOD) o Absent septum pellucid urn o Frontal horns "pointed" inferiorly o "Squared" or "box-like" appearance of lateral ventricles on coronal imaging o Small optic chiasm • Holoprosencephaly o Many people consider lobar holoprosencephaly = SOD Helpful Clues for Rare Diagnoses • Neurocysticercosis o Racemose NCC cysts in suprasellar cistern surround, stretch/thin infundibular stalk • Meningitis o Children with group B streptococcus o Diencephalic infarction o Secondary atrophy of optic chiasm, pituitary stalk

Pituitary Stalk Transection, Post- Traumatic

I 8 44

Coronal T7WI MR in a child with remote head trauma who subsequently developed pituitary insufficiency shows traumatic cephalocele and absenUinapparent pituitary stalkEl.

=

SagitIBI T1 WI MR alter lfanssphenoidal hypophysectomy shows very thin inlundibular stalk EI along with secondary empty sella

=.

ABSENT/THIN

INFUNDIBULAR

en ,.-

STALK

c:

III

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a.

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Pituitary Stalk Anomalies (Left) Sagittal TI WI MR in a 2 year old child with short stature, abnormally low bone age shows absent infundibular stalk

a

ectopic

posterior

pituitary

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(1)

OJ

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5i rJl

bright spot ell and small pituitary gland r=J. (Right) Coronal TlWI MR in the

(1)

..•

III

same patient as the previous image shows absent stalk 81 and ectopic

pituitary

posterior

bright spot hypothalamus =:II. II

II

in

(Left) Sagittal TI WI MR

shows two small-sized

pituitary stalks =:II in this case of duplicated pituitary stalks. Note abnormal configuration of posterior pituitary 81. (Right) Coronal T7 WI MR in the same case

as previous image shows thinned, duplicated in(undibular stalks 81.

(Left) Coronal T2WI MR shows classic SOD with thin stalk inferiorly "pointed" frontal horns ell and absent septum pellucidum with "squared

off" appearance

of

lateral ventricles 81. (Right) Sagittal TI C+ MR shows racemose NCC cysts surrounding, stretching infundibular stalk 81 and extending into sella, flattening pituitary gland against floor =:II.

I 8 45

c

THICK INFUNDIBULAR STALK

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c

a::

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(f)

DIFFERENTIAL DIAGNOSIS Common • Neurosarcoid • Germinoma

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co

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en

less Common • Meningitis • Histiocytosis • Lymphocytic

Hypophysitis

Rare but Important • Metastasis (to Stalk/Pituitary) • Ectopic Neurohypophysis • Pituicytoma • Lymphoma, Primary CNS • Leukemia • Transected Pituitary Stalk

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Know what normal stalk looks like! o Tapers from top (at tuber cinereum) to bottom (pituitary gland) o 2 mm or less in diameter • "Thick" stal k o More than 2 mm diameter o Loss of normal "top to bottom" tapering • Patient age extremely important in differential diagnosis of thick stalk o Child = histiocytosis, germinoma o Adult = neurosarcoidosis, hypophysitis, metastasis, lymphoma

Helpful Clues for Common Diagnoses • Neurosarcoid o Isolated stalk lesion uncommon o Adults> > children • Germinoma o May be primary in stalk/hypothalamus o Often presents with diabetes insipidus (D!) Helpful Clues for less Common Diagnoses • Meningitis o "Stalkitis" usually part of generalized pia-subarachnoid space infection o Isolated stalk infection rare • Histiocytosis o Calvarium> brain parenchyma, meninges o Infundibulum/hypothalamus = most common CNS site • Children> adults • Absent pituitary "bright spot" common • Stalk thick, hyperintense, enhancing • Lymphocytic Hypophysitis o Thick, enhancing stalk ± pituitary mass Helpful Clues for Rare Diagnoses • Metastasis, Lymphoma o Look for other lesions, infiltration of adjacent structures • Pituicytoma o Posterior pituitary "bright spot" often absent Other Essential Information • Pituitary stalk anomaly, transected stalk (traumatic/post-surgical) can make stalk appear "stubby"

Neurosarcoid

I 8 46

Germinoma

Sagittal T I C+ MR shows a diffusely thickened, intensely enhancing piwitary stalk in an adult with known

shows

inlracraniaJ

infundibulum ~ hypothalamus/anterior

= sarcoidosis and diabetes insipidus. This was the only lesion.

Sagittal T7 C+ MR in a 13 year old girl with central 01

enhancing suprasellar mass and extending 3rd ventricfe.

=

involving into

/he

THICK INFUNDIBULAR

STALK

(fl

c: " III

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(Left) Sagittal T I C+ MR in a patient with coccidioidomycosis meningitis E!l:I shows diffuse thickening and enhancement along the infundibular stalk and hypothalamus t±. (Right) Sagittal T1 C+ MR in a child with known Langerhans cell histiocytosis and central 01 shows a thickened, rounded, enhancing infundibular stalk =:1. This was the only intracranial lesion.

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(I)

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Metastasis (to Stalk/Pituitary) (Left) Sagittal T1 C+ MR in a middle-aged man presenting with 01 shows thickened infundibular/hypothalamic enhancing mass. Pre-operative diagnosis was granulomatous disease. Biopsy showed LH. (Rigllt) Sagittal T1 C+ MR in a patient with 01 and widespread systemic metastases shows enhancing mass infiltrating

pituitary

and

thickening infundibulum =:1. This was the only intracranial lesion.

(Left) Sagittal T1 C+ MR in a child with growth failure shows bulbous enlargement of the infundibulum small pituitary gland =:1 and absent "bright SpOI." (Right) Sagittal T1 C+ MR in a 22 year old woman with delayed growth, hypopituitarism for 6 years shows an intensely enhancing mass in the infundibular stalk extending into the hypothalamus.

=

=

I 8 47

c

HYPOTHALAMUS LESION

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DIFFERENTIAL DIAGNOSIS Common • Pilocytic Astrocytoma • Diffuse Astrocytoma, Low Grade Less Common • Craniopharyngioma • Germinoma • Neurosarcoid • Langerhans Cell Histiocytosis • Lipoma • Lymphocytic Hypophysitis • Metastases o Hypothalamic/Pituitary Axis Metastases o Lymphoma o Leukemia • Tuber Cinereum Hamartoma • Ectopic Posterior Pituitary Rare but Important • Other Gliomas o Chordoid Glioma o Pilomyxoid Astrocytoma o Pituicytoma o Ganglioglioma • Demyelinating Disease o Multiple Sclerosis o ADEM • Wernicke Encephalopathy • Cavernous Malformation

ESSENTIAL INFORMATION

I 8 48

Helpful Clues for Common Diagnoses • Astrocytoma o Most common primary neoplasm of hypothalamic-optic chiasm region o Usually low grade (pilocytic > WHO grade II fibrillary) o Age < 5 years o Endocrine dysfunction in 20% o Look for evidence for NFl • 20-50% of patients with pilocytic astrocytoma Helpful Clues for Less Common Diagnoses • Craniopharyngioma o Second-most common suprasellar mass in children o Occurs anywhere from intrasellar to stalk to anteroinferior 3rd ventricle o 90% calcify, 90% have multiple cysts (mixed signal intensity), 90% calcify • Germinoma o Can be primary in hypothalamus/stalk • M = F (vs. male predominance in pineal gland) o 10% "double" midline lesions (pineal & hypothalamus) o DI, diencephalic syndrome, precocious puberty common o Thick enhancing stalk, 3rd floor, absent posterior pituitary "bright spot" • Neurosarcoid o Adult with stalk, meningeal lesions o Other infectious/inflammatory lesions that can mimic sarcoid • Wegener granulomatosis • TB, syphilis • Langerhans Cell Histiocytosis o Stalk/hypothalamus lesion in a child • Lipoma o Lipoma: Sessile T1 hyperintense lesion on subpial surface of hypothalamus o Osteolipoma: Rare; fat density/signal intensity & calcification • Lymphocytic Hypophysitis o Peripartum female most common o Can mimic macroadenoma • Metastases o Hypothalamic/Pituitary Axis Metastases • 1-25% of systemic cancers at autopsy • Less common at imaging • Breast, lung most common primary tumors

HYPOTHALAMUS

en ;1r:

lESION

c:

Lymphoma • Pituitary/stalk/hypothalamus uncommon site • Can be primary or metastatic a Leukemia • Often involves dura, paranasal sinuses • Tuber Cinereum Hamartoma a Children with gelastic seizures, males with isosexual precocious puberty a Can be pedunculated or sessile a Density/signal intensity typically isointense with cortex a No Ca++, enhancement a Sessile lesion may be difficult to distinguish from hypothalamic astrocytoma (no change on follow-up) a

Helpful Clues for Rare Diagnoses • Other Gliomas a Chordoid Glioma • Floor of 3rd ventricle • Hyperintense with strong, uniform enhancement a Pilomyxoid Astrocytoma • Infant/young child • "H"-shaped tumor of hypothalamus; extension into medial temporal lobes common • Often large, bulky, ± hemorrhage (rare in pilocytic astrocytoma) • ± Hemorrhage (25% of PMAs; rare in pilocytic astrocytoma) a Pituicytoma • Stalk, posterior pituitary lobe

Sagittal T2WI MR shows classic pilocytic astrocytoma =:I originating from hypothalamus and optic chiasm. (Courtesy P.Rodriguez, MO).

• Low grade astrocytoma • Enhances strongly, uniformly a Ganglioglioma • Very rare in hypothalamus/chiasm • Young adult (mean age = 20 years) • Demyelinating Disease a Optic chiasm involvement> > hypothalamus a Enhancing, slightly enlarged optic nerves/chiasm seen with both MS, ADEM • Wernicke Encephalopathy a Acute: Abnormal hyperintensity/enhancement of mamillary bodies, inferolateral walls of 3rd ventricle, periaqueductal gray matter a Chronic: Mamillary atrophy a Note: Occurs in both alcoholics, nonalcoholics (e.g., long-standing parenteral nutrition) • Cavernous Malformation a Hypothalamus/3rd ventricle rare location a Looks like CM elsewhere

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Other Essential Information • Child with DI, no visible lesion may have germinoma; surveillance with Tl C+ scans essential!

SELECTED ].

2.

REFERENCES

Hamilton BE et al: Anatomic and pathologic spectrum of pituitary infundibulum lesions. AJR Am J Roentgenol. 188(3):W223-32,2007 Saleem SN et al: Lesions o( the hypothalamus: MR imaging diagnostic features. Radiographies. 27(4):1087-108, 2007

Sagillal TI C+ MR shows inhomogeneously enhancing

mass in anterior 3rd venlIicle, hypothalamus

=.

I 8 49

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HYPOTHALAMUS

o en

LESION

Ql

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.:

ro

Ql (/)

ro

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--,::J

Iii Qj (/) C l'Cl

"CD "C

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Germinoma (Left) Sagittal T1WI MR shows large hyperintense craniopharyngioma

originating from the 3rd ventricle ~ and hypothalamus. Note sparing of the suprasellar cistern [;8 (Right) Sagillal T1 C+ MR in 13 year old boy with central diabetes insipidus shows enhancing

mass in anterior

3rd ventricle/hypothalamus I:]] displacing pituitary stalk ~ anteriorly.

Neurosarcoid (Left) Sagillal T1 C+ MR shows an enhancing mass infiltrating hypothalamus I:]] and infundibular stalk. Patient is an adult who presented with diabetes insipidus. (Right) Sagittal T1 C+ MR in child with DI shows enhancing mass infiltrating the hypothalamus,

=

tuber cinereum,

infundibular

stalk, and pituitary gland.

(Left) Sagittal T1 C+ MR shows enhancing mass in anterior third ventricle, hypothalamus 1:]]. The pituitary stalk E!:J is slightly thickened. (Right) Sagittal T1 C+ fS MR shows pituitary hypothalamic E!:J masses in this patient with proven B-cell lymphoma.

=-

I 8 50

Langerhans Cell Histiocytosis

HYPOTHALAMUS

LESION III

::::l

Co

-.

III

Tuber Cinereum

Hamartoma

Chordoid

Glioma

III

(Left) Sagittal T2WI MR in a 12 year old child with gelastic seizures shows sessile hypothalamic mass with cyst 81. No enhancement was seen on T1 C+ scan. Variant cases

=

may mimic

astrocytoma.

(Right) Sagittal T1 WI MR in this 6S year old patient shows isoinlense hypotha/amic/3rd ventricular mass displacing, compressing optic chiasm !:J:I. Intense homogeneous enhancement was seen on T1 C+ slUdy.

=

Pilomyxoid

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Astrocytoma (Left) Sagittal T2WI MR in a 3 year old child with NF I and diencephalic syndrome shows large hyperintense hypothalamic mass bulging into anterior

3rd ventricle

6>J. (Right) Sagillal T I C+ MR in a 22 year old woman with hypopituitarism shows large enhancing hypothalamic/infundibular stalk mass!:J:I.

Multiple

Sclerosis (Left) Sagillal fLAIR MR shows mullifocaf hyperintensiUes along the callososeptal interface and in the hemispheric white matter, as well as optic chiasm/hypothalamus ~ (RighI) Axial FLAIR MR in patient with long-standing hyperalimentation shows hyperintensity in mammillary bodies as well as periaqueductal gray maller

19.

I 8 51

c

HYPERDENSE SUPRASEllAR MASS

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DIFFERENTIAL DIAGNOSIS Common • Pituitary Macroadenoma • Aneurysm o Saccular Aneurysm o Fusiform Aneurysm, ASVD • Meningioma Less Common • Craniopharyngioma • Rathke Cleft Cyst • Germinoma • Neurosarcoid Rare but Important • Parenchymal Metastases • Primary CNS Lymphoma • Pilomyxoid Astrocytoma • Tuberculosis • Fungal Diseases • Chordoid Glioma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Is mass from pituitary gland or other structure? Helpful Clues for Common Diagnoses • Pituitary Macroadenoma o Approximately 10% hyperdense • Cellularity, hemorrhage o Pituitary gland can't be separated from mass • Gland is the mass

• Saccular Aneurysm o Nonthrombosed aneurysms slightly hyperdense to brain o Partially/completely thrombosed aneurysms may be very hyperdense • Fusiform Aneurysm, ASVD o May involve either ICA or BA o on aneurysmal dolichoectasia common in older patients o ASVD > non-ASVD (e.g., inherited vasculopathy, AIDS-related, etc.) o ASVD often Ca++ • Meningioma o 10% in sellar/suprasellar region o Pituitary gland separate from mass Helpful Clues for Less Common Diagnoses • Craniopharyngioma o Children: Adamantinomatous type • Usually cystic, Ca++ • Rarely hyperdense o Adults: Papillary type more common • Iso/slightly hyperdense • Solid, rarely calcified • Rathke Cleft Cyst o Only 10% purely suprasellar, hyperdense • Germinoma o Mildly hyperdense to brain o Look for pineal mass (but can be primary infundibulum/3rd ventricle lesion) Alternative Differential Approaches • Hyperdense suprasellar mass with Ca++ o Children: Craniopharyngioma o Adults: Aneurysm, meningioma

Pituitary Macroadenoma

I 8 52

Axial NECT in a 60 year old woman presenting in the emergency department with severe headache shows a hyperdense mass in the suprasellar cistern !:ill. Scout view (not shown) demonstrated an expanded sella.

Axial NECT in a patient with headache and bitemporal hemianopsia shows a somewhat lobulated hyperdense suprasellar mass !:ill. CTA demonstrated partially thrombosed lCA aneurysm.

HYPERDENSE

SUPRASEllAR

MASS III

::l Cl.

to ., III

(Left) Axial NECT in elderfy woman with "altered mental staWs /I shows very large, hyperdense, partially calcified frontal/suprasellar mass =:I. NOle acute obstructive hydrocephalus SlI. (Rig"') Axial NECT shows a hyperdense suprasellar mass SlI that contains punctate calcifications DJ. Craniopharyngioma was found at surgery.

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Germinoma (Left) Axial NECT in a patient with headaches and normal neurologic examination shows a hyperdense sellar/intrasellar mass =:I. MR showed Rathke cleft cyst with classic inlracystic nodule. (Right) Axial NECT in a 22 year old man with headaches, lethargy, and diabetes insipidus shows a hyperdense suprasellar mass MR showed a 2nd lesion in the pineal gland.

Tuberculosis (Left) Axial NECT shows hyperdense suprasellar mass Extension into cavernous sinus helps distinguish this from many other entities

in this location. (Right) Axial N[CT in a patient with known tuberculosis shows an inhomogeneously hyperdense suprasellar mass DJ. Rim enhancement was seen following contrast in this patient with caseating tuberculoma.

I 8 53

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T1 ISOINTENSE SUPRASELLARMASS

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DIFFERENTIAL DIAGNOSIS Common • Pituitary Macroadenoma • Pituitary Hyperplasia • Meningioma • Pilocytic Astrocytoma • Diffuse Astrocytoma, Low Grade Less Common • Rathke Cleft Cyst • Germinoma • Neurosarcoid • Langerhans Cell Histiocytosis • Tuber Cinereum Hamartoma • Lymphocytic Hypophysitis Rare but Important • Metastasis (Pituitary &/or Stalk) • Pituicytoma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Where does lesion arise from? o Pituitary gland/sella turcica (macroadenoma, hyperplasia, hypophysitis, metastasis) o Infundibulum (germinoma, histiocytosis, pituicytoma) o Brain (astrocytoma), meninges (meningioma) • Does it enhance? o Yes: Macroadenoma, meningioma, aneurysm, neoplasm

No: Tuber cinereum hamartoma, RCC • Few lesions remain isointense with cortex on all MR sequences o Pituitary macroadenoma or hyperplasia o Meningioma, tuber cinereum hamartoma o Histiocytosis, sarcoidosis o

Helpful Clues for Common Diagnoses • Pituitary Macroadenoma, Hyperplasia o Both isointense to gray matter (GM) • Meningioma o Usually isointense on all sequences o ± Ca++, enhances • Astrocytomas (pilocytic > diffusely infiltrating) o Usually iso-/hypo- on Tl, hyperintense on T2WI o Variable enhancement (none to striking) Helpful Clues for Less Common Diagnoses • Rathke Cleft Cyst (depends on cyst content) o Most are hypointense o 25% iso-, 10% hyperdense o Rim may enhance ("claw sign") • Germinoma o Isointense on Tl-, iso/hypo on T2WI o Enhances strongly, uniformly • Neurosarcoid, Langerhans Cell Histiocytosis o LCH (child), sarcoid (adult) - thick, enhancing stalk • Tuber Cinereum Hamartoma o > 90% isointense on Tl WI, non enhancing o May be slightly hyperintense on PD, FLAIR

Pituitary Macroadenoma

I 8 54

Coronal TJWI MR shows a large intra- and suprasellar mass elevating and compressing the optic chiasm m. The mass cannot be distinguished from the pituitary

m that is isoinlense

gland.

gland below

=

Sagittal T7WI MR shows an intra- and suprasellar mass with gray maHer. The diaphragma

sellae ~

clearly separates the mass from the pituitary

T1 ISOINTENSE SUPRASEllAR

MASS

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c: " III

:J Co

OJ "'"

III

(Left) Axial T1WI MR shows an enlarged optic chiasm c;. and nerves in this patient with neurofibromatosis type

1. (Right) Axial T1WI MR shows a slightly inhomogeneous suprasellar mass I:] that is largely isoinlense with adjacent brain.

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ell Q)

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Ci ~ [fl

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Tuber Cinereum

Hamartoma (Left) Coronal T1 WI MR in 21 year old woman shows a well-delineated

isoinlense

suprasellar mass I:]slightly displacing the inlundibular stalk to the lelt and the pituitary gland inleriorfy. This incidental finding is a presumed Rathke clelt cyst. (Right) Sagittal T1 WI MR in a 77 year old woman with precocious puberty shows a classic "collar button"

=

lesion positioned

between

the inlundibulum i/1 Iront E2 and the mamillary body behind~.

(Left) Sagittal T1WI MR in a 42 year old man with diabetes insipidus and headache shows an isoinlense suprasellar mass CO> elevating and compressing the optic chiasm. (Rigl1t)Sagittal T IWI MR in a patient with visual

problems and diabetes insipidus shows an ;so;ntens€ suprasellar mass arising from

the inlundibular stalk 1:]. The lesion enhanced strongly and uniformly. (Courtesy A Hasso, MO).

I 8 55

c

11 HYPERINTENSE SUPRASELLAR MASS

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DIFFERENTIAL DIAGNOSIS Common • Pituitary Macroadenoma • Craniopharyngioma Less Common • Saccular Aneurysm (Thrombosed) • Rathke Cleft Cyst • Ectopic Neurohypophysis • Lipoma • Dermoid Cyst Rare but Important • Pituitary Apoplexy • Pilomyxoid Astrocytoma • Cavernous Malformation • Meningioma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Most common cause for t Tl is subacute hemorrhage o T2* (GRE or SWI) useful • Age helpful in common diagnoses o Children = craniopharyngioma o Adults = pituitary macroadenoma, thrombosed aneurysm Helpful Clues for Common Diagnoses • Pituitary Macroadenoma o Hemorrhage, sometimes cystic change • Craniopharyngioma o 90% Ca++, 90% cystic, 90% enhance

o

"Crankcase" oily content hyperintensity

..• Tl

Helpful Clues for Less Common Diagnoses • Saccular Aneurysm (Thrombosed) o Usually eccentrically located, not directly suprasellar o Subacute/chronic mural thrombus • Rathke Cleft Cyst o May have very short Tl if high protein content or hemorrhage from cyst apoplexy o Look for intracystic nodule o Look for "claw" of enhancing pituitary gland wrapped around cyst • Ectopic Neurohypophysis o Pituitary stalk tiny or nonexistent o "Bright spot" on hypothalamus o Does not saturate with fat suppression • Lipoma o Suppresses with fat saturation • Dermoid Cyst o Fat droplets in sulci, cisterns (ruptured) Helpful Clues for Rare Diagnoses • Pituitary Apoplexy o Subacute hemorrhage has short Tl o Rim enhancement typical • Pilomyxoid Astrocytoma o May hemorrhage • Cavernous Malformation o "Popcorn" appearance • Meningioma o • Tl (psammomatous Ca++; hemorrhage, lipomatous transformation rare)

Pituitary Macroadenoma

Craniopharyngioma

I 8 56

Sagittal TI WI MR shows a hemorrhagic intra- and suprasellar mass in a patient who presented with pituitary apoplexy. The diagnosis was macroadenoma with subacute hemorrhage.

=

Coronal

TlWI

MR

shows

hyperintense suprasellar mass ffi inCJasellarcomponent is seen

BI.

a

homogeneously

A

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Craniopharyngioma

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Saccular Aneurysm (Thrombosed)

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Rathke Cleft Cyst (Left) Sagittal T1 WI MR shows a mixed signal, mostly hyperintense, suprasellar mass Note a "flow void" from the anterior cerebral artery SI supplying this largely thrombosed giant aneurysm. (Right) Sagittal T1WI MR shows a presumed Rathke cleft cyst, seen here as a well-delineated hyperintense suprasellar mass ~ clearly separable from pituitary gland. This was found incidentally on a standard MR scan.

=.

Dermoid

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Cyst (Left) Sagittal T1 WI MR shows a hyperintense hypothalamic mass with absent infundibulum. Anterior pituitary ~ is normal to slightly small in size. Note the lack of a "bright" neurohypophysis. (Right) Axial T1WI MR shows a mixed signaf~ primarily hyperintense mass SI in the suprasellar and quadrigeminal cisterns. Note fat droplets in subarachnoid spaces in this

=

=

patient

with ruplUred

dermoid cyst.

Cavernous Malformation

Meningioma (Left) Sagittal T1 WI MR shows a mixed iso-, hyperintense suprasellar mass E±I with hypointense rim [;8 characteristic of Zabramski type 2 cavernous malformation. (Right) Axial T1WI MR shows mostly isointense suprasellar mass with

some

Tl shortening

ED.,

possibly caused by psammomatous calcification, not hemorrhage.

I 8 57

11 HYPOINTENSE SUPRASELLAR LESION

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DIFFERENTIAL DIAGNOSIS

o

Rim/ring (NCC, craniopharyngioma,

RCC)

Helpful Clues for Common Diagnoses • Dilated Third Ventricle o Enlarged 3rd ventricle recesses protrude into suprasellar cistern, sella turcica o Behaves exactly like CSF on FLAIR, OWl • Arachnoid Cyst (AC) o Bows 3rd ventricle up, over cyst o Suppresses on FLAIR, no restriction on OWl • Neurocysticercosis (NCC) o Cysts often show rim enhancement

Common • Dilated Third Ventricle • Arachnoid Cyst (AC) • Neurocysticercosis (NCC) Less Common • Pilocytic Astrocytoma (PA) • Craniopharyngioma • Epidermoid Cyst • Rathke Cleft Cyst • Enlarged Perivascular Spaces

III

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-"(/)

Rare but Important • Pituitary Macroadenoma • Saccular Aneurysm (Acutely Thrombosed) • Pituitary Apoplexy • Pilomyxoid Astrocytoma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Tl hypointense lesion = hypointense compared to brain, not necessarily - CSF • Lesions CSF-like on all sequences o Enlarged 3rd ventricle, arachnoid cyst, perivascular spaces o Epidermoid cyst • Lesions hypointense to brain but hyperintense to CSF on Tl WI o Neoplasms o Congenital or infectious cysts • Enhancing hypointense lesions o Solid (astrocytoma, adenoma)

Helpful Clues for Less Common Diagnoses • Pilocytic Astrocytoma (PA) o Hyperintense to CSF on Tl WI o Enhancement typical • Craniopharyngioma 090% cystic, 90% Ca++, 90% enhance o Cyst signal variable (hyper> hypointense) • Epidermoid Cyst o No suppression on FLAIR, restricts on OWl • Rathke Cleft Cyst o Cyst fluid more often hyperintense o Look for "claw sign" of enhancing pituitary around cyst Helpful Clues for Rare Diagnoses • Pituitary Macroadenoma o Small intratumoral cysts common o Extratumoral cysts (trapped perivascular spaces) less common o Necrosis/apoplexy may appear cystic, show rim enhancement

Dilated Third Ventricle

I 8

Sagittal T7 WI MR shows aqueductal stenosis 81 causing marked enlargement or the third ventricle with herniation

58

cistern I!!f].

of anterior

recesses into

the suprasellar

=-

Sagittal T7 C+ MR shows a CSF-like suprasellar mass compressing/elevaUng the 3rd ventricle deviating lhe inFundibulum anteriorly E1 and causing severe obstrucUve hydrocephalus.

T1 HYPOINTENSE

SUPRASELLAR

en

LESION

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ro ., Ql

(Left) Sagittal T1 C+ MR shows multiple hypoimense basal cYS15with peripheral enhancemenl~in the supra· and intrasellar ~ cisterns. (Right) Axial T1 WI MR in child with known NFl shows a lobulated hypointense mass filling the suprasellar cistern. The mass enhanced strongly but heterogeneously following contrast administration.

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CD

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(Left) Coronal T1WI MR shows a mixed ;50- EI and hypointense suprasellar mass in a child with chiasm compression ~ causing bitemporal hemianopsia. Hypoinleflsily in this case is caused by dense calcification. (Right) Axial T1 C+ FS MR shows a lobulated, CSF-Iike, non enhancing mass infiltrating the quadrigeminal, ambient 1:1 and suprasellar cisterns

=

a

Enlarged Perivascular Spaces

Saccular Aneurysm (Acutely Thrombosed) (Left) Axial T1 WI MR shows variable-sized CSF-like cYS15 E±J in hypothalamic region. Prominent PV5s are common in basal ganglia, less common in midline basal brain structures. (Right) Axial T1 C+ MR shows nonenhancing, hypoinlense, intra- & suprasellar mass I::] in a female with headache & sudden onset left CN6 palsy. Pituitary apoplexy was pre-operative diagnosis. An

rs

acutely thrombosed internal carotid artery aneurysm was found at surgery.

I 8 59

SECTION 9 Arteries Anatomically Based Differentials Abnormalities of Arterial Shape/Configuration Fusiform Arterial Enlargement

Modality-Specific

1-9-2 1-9-6

Imaging Findings

Hyperattenuating ("Dense") Artery Vascular Calcification(s)

1-9-8

1-9-10

ABNORMALITIES OF ARTERIAL SHAPE/CONFIGURATION

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DIFFERENTIAL DIAGNOSIS Common • Atherosclerosis, Intracranial • Dolichoectasia • MR Artifacts, Flow-Related • Saccular Aneurysm • Fusiform Aneurysm, ASVD Less Common • Vasospasm • Fusiform Aneurysm/Vasculopathy, Non-ASVD • Dissection • Pseudoaneurysm Rare but Important • Blood Blister-like Aneurysm • Vasculitis • Moyamoya

ESSENTIAL INFORMATION

I 9 2

Key Differential Diagnosis Issues • Effect of patient age on diagnosis o Middle-aged or elderly • Atherosclerosis (ASVD) • Dolichoectasia • Saccular aneurysm • Fusiform aneurysm o Child or young adult • Consider inherited vasculopathy (e.g., collagen-vascular disease like Ehlers-Danlos) • Child with fusiform vasculopathy: Check HIV status • Moyamoya • Is there evidence for hemorrhage? o Subarachnoid • Saccular aneurysm ± vasospasm • Blood blister-like aneurysm • Dissection or dissecting aneurysm (especially vertebrobasilar) o Parenchymal • Moyamoya (adult) • Vasculitis (especially drug-related) • Pseudoaneurysm (especially with trauma history) • Does lesion involve short or long segment of vessel, bifurcation vs. nonbranching point? o Short, bifurcation -+ saccular aneurysm,

ASVD

o o

Short nonbranching -+ pseudoaneurysm, blood blister-like aneurysm Long, nonbranching -+ ASVD, dolichoectasia, fusiform aneurysm (ASVD, non-ASVD), vasculitis, vasospasm

Helpful Clues for Common Diagnoses • Atherosclerosis, Intracranial o Distal basilar artery (BA), cavernous/supra clinoid internal carotid artery (lCA) > cortical branches o Findings • ormal aging: Arterial Ca++, wall thickening • Most common: Focal stenosis, luminal irregularities • Less common: Elongation/ectasia • Uncommon: Thrombosis, occlusion o Remember: Most common cause of "vasculitis" appearance is ASVD, not vasculitis! • Dolichoectasia o Elongation, dilatation, tortuosity without focal aneurysmal dilatation o BA > ICA > MCA o Slow flow may cause signal inhomogeneity, phase artifact • MR Artifacts, Flow-Related o Pulsation may cause spin dephasing, signal loss in adjacent CSF (especially around distal basilar artery) o Phase artifact propagation may distort vessel contours, propagate across imaged slice o Slow flow & fully relaxed spins in entry slice(s) -+ Tl shortening may mimic thrombus • Saccular Aneurysm o Round or ovoid outpouching ± "tit" or lobulations o Arises from major vessel bifurcation o Variable neck (narrow, wide, broad-based) o Aneurysmal SAH common • Fusiform Aneurysm, ASVD o Long segment irregular fusiform/ovoid arterial dilatation o Vertebral arteries, BA > ICA, MCA o Hematoma with variable aged clot common o Residual lumen enhances strongly o Variant = "giant serpentine aneurysm" • Large, partially thrombosed mass

ABNORMALITIES OF ARTERIAL SHAPE/CONFIGURATION • Clot of varying age • No definable neck Helpful Clues for Less Common Diagnoses • Vasospasm o Etiology • Most common: Ruptured aneurysm ~ aSAH ~ vasospasm 5-7 days later • Less common: Trauma o Imaging • Long- or short-segment stenosis • Often multifocal • ± Cerebral ischemia/infarction • Fusiform Aneurysm/Vasculopathy, Non-ASVD o Fusiform or ovoid dilatation in absence of ASVD o Long, affects nonbranching vessel segments o Can be solitary or multifocal o Vertebral/BA > carotid o Younger patients o Inherited (e.g., Ehlers-Danlos) or acquired (viral or collagen-vascular) • Dissection o Can be traumatic or spontaneous o May cause SAH o Vertebral> > internal carotid artery o Look for Tl hyperintense clot around residual lumen o Focal dilatation ~ dissecting aneurysm • Pseudoaneurysm o Cavitated clot lacks normal arterial wall o Trauma, infection = common causes

Atherosclerosis,

Peripheral location (distal to circle of Willis) o Often adjacent to skull base or dura (tentorial incisura, falx) o

Helpful Clues for Rare Diagnoses • Blood Blister-like Aneurysm o Broad-based hemispheric bulge o No definable neck o Contained only by adventitia/fibrous cap so easily ruptures o Look carefully for BBA in "angiogram-negative" SAH o Most common location = supraclinoid ICA • Vasculitis o Primary arteritis of the CNS o Secondary vasculitis • Infectious • Autoimmune • Substance abuse • Radiation-induced o Multifocal alternating stenoses, dilatations o Remember: Most common cause of "vasculitic" pattern in older patient is ASVD! Other Essential Information • Mimics of arterial abnormalities o Anything with short Tl can mimic aneurysm on MRA • Lipoma • Pituitary gland on Tl C+ • ROI that includes part of adjacent vessel o Pulsation artifact

Dolichoectasia

Intracranial

I Anteroposterior angiography shows mulUfocal stenoses characteristic for atherosclerosis (ASVD). ASVD is most common cause of this vasculitis-like pattern of alternating stenoses and dilatations.

Axial T1WI generalized €CtaUcMCA the pulsating

MR in normal 79 year old man with arterial dolichoeclasia shows elongated. =.2 with substanUal phase arUfact SI from vessel.

9 3

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ABNORMALITIES

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OF ARTERIAL SHAPE/CONFIGURATION

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(Left) Axial T2WI MR shows CSF "f/ow void" & around the distal basilar artery, a common finding with hyperdynamic but normal arterial pulsation that is especially common in children. (Right) Lateral angiography with 3D prominent

reconstruction

from selective

DSA of right internal carotid artery shows typical multilobulated saccular aneurysm junction

=

arising from

of internal

posterior

carotid,

communicating

arteries.

Fusiform Aneurysm, ASVD

Fusiform Aneurysm, ASVD

(Left) Sagittal MRA reprojected from axial data shows huge fusiform basilar artery aneurysm in this 61 year old man with posterior circulation TlAs. Most of the aneurysm is filled with thrombus~. Flow in residual patent lumen is present (Right) Lateral angiography shows bizarre,

=.

fusiform ectasia

of middle

cerebral artery ffi extending into M2 segment in sylvian fissure :i8

Vasospasm (Left) Lateral angiography shows a saccular aneurysm

(;>J and narrowed cortical vessels ~

indicating a

vasospasm caused by an aneurysmal subarachnoid hemorrhage (aSAI I). (Right) Lateral angiography in 47 year old man with spontaneous intracranial hemorrhage (not shown) shows fusiform elongation of an MCA branch ~ Patient later admitted to using street drugs.

I 9 4

Fusiform Aneurysm/Vasculopathy, Non-ASVD

ABNORMALITIES

en ,.-

OF ARTERIAL SHAPE/CONFIGURATION

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Fusiform Aneurysm/Vasculopathy, Non-A5VD

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(Left) Axial T2WI MR in a 13 yea, old child with II/VIAIOS shows enlarged, bizarre-appearing middle cerebral arteries 3-. (Right) Axial T7 C+ FS MR in a

patient

with

:>

posterior

circulation ischemic symptoms several days after a severe deceleration injury shows that both vertebral

arteries are markedly enlarged by subacute clot

=. Right VA appears

completely thrombosed, while small residual lumen is seen on left 81.

Pseudoaneurysm

Blood Blister-like Aneurysm (Left) Axial MRA shows traumatic pseudoaneurysm arising from P2 segment of posterior cerebral artery Impaction against tentorium during CJ 1/ probably injured PCA, creating this gradually enlarging pseudoaneurysm. (Right) Lateral angiography shows classic blood blister-like aneurysm c7 along greater curvature of supra clinoid internal carotid artery. Hemispherical bulge with broad orifice is typical for BBAs. (Courtesy D. Phillips, MO).

Vasculitis

Moyamoya (Left) Sagittal oblique angiography shows classic changes of vasculitis, with alternating areas of stenosis and dilatation ffi Note pseudoaneurysm ~ a rare complication of vasculitis. (Right) Lateral angiography shows tapered occlusion ~ of supra clinoid internal carotid artery, with tangle of

"puff of smoke lenticulostriate collaterals.

II

:t>-

I 9 5

rn

FUSIFORM ARTERIAL ENLARGEMENT

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DIFFERENTIAL DIAGNOSIS Common • Dolichoectasia • Atherosclerotic • Nonaneurysmal

Fusiform Aneurysm Dissection

Less Common • Dissecting Aneurysm/Pseudoaneurysm • Vasculitis • Nonatherosclerotic Fusiform Aneurysm/V asculopath y o Neurofibromatosis Type 1 o Systemic Lupus Erythematosus o Ehlers-Danlos IV o Marfan Syndrome Rare but Important • Giant "Serpentine" Aneurysm • Atypical Saccular Aneurysm

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Ectasia = elongated/tortuous artery • Fusiform aneurysm o Long segment fusiform arterial dilatation o Can be acute (dissecting) or chronic (ASVD, nonatherosclerotic vasculopathy) Helpful Clues for Common Diagnoses • Dolichoectasia o Dilated/elongated arteries ± slow flow o Vessel layers intact o Older patients

Most common manifestation of intracranial ASVD o Vertebrobasilar > internal carotid artery o Ectasia often extends into branches • Atherosclerotic Fusiform Aneurysm o Thick wall ± organized thrombus o Variable slow flow • Nonaneurysmal Dissection o Vertebral> basilar> internal carotid artery o Lacks changes of ASVD in other vessels o Can be spontaneous or traumatic o

Helpful Clues for Less Common Diagnoses • Dissecting Aneurysm/Pseudoaneurysm o Focal arterial dilatation o Trauma = most common etiology o Next to hard/fixed structures (bone, dura) • Vasculitis o Involves multiple vessels o Alternating stenoses/dilatations • Nonatherosclerotic Fusiform Aneurysm/Vasculopathy o Younger patient; history of inherited vasculopathy, immune disorder Helpful Clues for Rare Diagnoses • Giant "Serpentine" Aneurysm o Large, partially thrombosed mass o Distal branches arise from aneurysm dome o Lacks definable neck o ICA/MCA > vertebrobasilar artery • Atypical Saccular Aneurysm o Arises from vessel bifurcations o Long "aspect ratio" - fusiform appearance o Often multilobulated, bizarre

Dolichoectasia

I 9 6

Sagittal T7WI MR shows elongated basilar artery with slow flow, thickened waif =:II. Apex of tortuous basilar artery indents hypothalamus, 3rd ventricle BI.

Axial T2WI MR shows an elongated, tortuous basilar artery with thickened arterial waif ffi typical for atherosclerosis-associated fusiform ectasia.

FUSIFORM

ARTERIAL ENLARGEMENT III

~ Q.

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III

(LeFt) Sagittal T7 WI MR shows a large extra·axial

mass anterior to the

=.

brainstem Note signal caused by slow flow, laminated clot in this classic ASVD fusiform aneurysm. (Rig"') Axial T7 WI MR shows an enlarged right vertebral artery with high signal intensity as well as an absent "flow void" of the left vertebral artery PJ::I.

~

» ;:+ ro ::::!. ro U>

=

Dissecting Aneurysm/Pseudoaneurysm

Vasculitis (LeFt) Axial T7WI MR in a patient with remote closed head injury shows a hyperintense mass ~ ambient

cistern with

in the

a

hypointense "slow flow" ~ seen within the mass. (Right) Axial T2WI MR shows strikingly enlarged middle

cerebral arteries ~

in this

chi/d with congenital HIV/AIOS (an uncommon but well-recognized cause of pediatric fusiform arteriopathy) .

Nonatherosclerotic Fusiform Aneurysm/Vasculopathy (Left) Anteroposterior oblique view of the left vertebral angiogram shows focal elongations and widening of the basi/ar artery in a 6 year old child with Ehlers-Danlos type 4. (Right) Lateral angiography in 30 year old man with a subarachnoid Ijemorrhage shows an elongated, bizarre-appearing, multi/obulated aneurysm ~ with long "aspect ratio", tit-like projections.

I 9 7

(j) Q)

HYPERATTENUATING ("DENSE") ARTERY

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III

DIFFERENTIAL DIAGNOSIS Common • Physiologic Hyperdensity • Cerebral Ischemia-Infarction,

Acute

Less Common • Atherosclerosis, Intracranial • Polycythemia • Fusiform Aneurysm (ASVD, Non-ASVD) • Dissection • Pseudoaneurysm Rare but Important • Devices and Complications

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Presence, localization of focal neurologic findings important • High hematocrit/hemoconcentration can mimic "dense MCA sign"! o Compare to other intracranial vessels! • Diffuse low density brain (anoxia, etc.) makes ALL vessels appear hyperdense, mimics thrombus or SAH! Helpful Clues for Common Diagnoses • Physiologic Hyperdensity o Circulating blood in arteries normally slightly hyperdense to brain • Especially prominent in newborns with unmyelinated, hypodense brain

I 9 8

Axial NECT demonslIates relatively hyperdense internal

carotid arteries III] in this neonate. Note the corresponding increased density of the transverse sinuses=.

• Diffuse cerebral edema makes vessels appear hyperdense ("false dense MCA sign") • Cerebral Ischemia-Infarction, Acute o Acute thrombus in affected vessel (e.g., true "dense MCA sign") Helpful Clues for Less Common Diagnoses • Atherosclerosis, Intracranial o ASVD with microcalcifications can mimic "dense" MCA • Polycythemia o Can be physiologic (elevated hematocrit in newborns, high altitude, etc.) o umerous pathologic causes • Fusiform Aneurysm (ASVD, Non-ASVD) o Vertebrobasilar > carotid circulation o Thickened walls may appear hyperdense o Non-ASVD: Younger; inherited vasculopathy, immune disorder • Dissection o Most posterior circulation o Trauma most common etiology • Pseudoaneurysm o Trauma most common etiology Helpful Clues for Rare Diagnoses • Devices and Complications o Coils, balloons, stents, methacrylate, etc. o Embolized foreign bodies, calcified atheromata can cause hyperattenuating vessel sign

Axial NECT shows "false dense MCA sign" in a patient with diffuse cerebral edema. Low density brain makes normal MCA =:I and cerebellum SI appear hyperdense.

HYPERATTENUATING

("DENSE") ARTERY

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c: III

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to ... III

(Left) Axial NECT shows increased density ("dot sign") in a distal left middle cerebral artery (MCA) branch (Right) Axial NECT shows calcified embolus in MCA branch in patient with abrupt onset right-sided weakness.

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=.

=

(Left) Axial NECT shows calcification

in the

supraclinoid internal carotid arteries ffi (Right) Axial NECT shows hyperdense arteries 1m as well as veins and dural sinuses m in a patient with markedly elevated hematocrit. Polycythemia

can mimic

a

CECT scan but vessels are usually not as dense.

Dissection

Devices and Complications (Left) Axial NECT shows high density thrombus in the internal carotid artery PJ:J related to dissection of the left ICA just above the carotid bulb (not shown). (Right) Axial NECT shows embo/ized hyperdense material in the left MCA in an IV drug abuser, possibly secondary to talc powder. Adjacent hypodense parenchyma is in keeping with a subacute

=

infarct.

I 9 9

VASCULAR CALCIFICATlON(S)

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DIFFERENTIAL DIAGNOSIS Common • Physiologic Calcification, Vascular • Atherosclerosis, Intracranial • Diabetes • Saccular Aneurysm • Fusiform Aneurysm, ASVD Less Common • Chronic Renal Failure • Cavernous Malformation • Arteriovenous Malformation • Calcified Plaque Embolus • Hyperparathyroidism Rare but Important • Mineralizing Microangiopathy

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Atherosclerotic, diabetic, & renal failure calcifications are often comorbidities in the same patient Helpful Clues for Common Diagnoses • Physiologic Calcification, Vascular o Barely discernible mural calcifications without narrowing o Unaccompanied by evidence of disease o Only in medial layer; assoc. w/elastin • Atherosclerosis, Intracranial o Eccentric mural calcifications with focal lumenal narrowing o Mostly in intimal layer; assoc. w/collagen

Physiologic

I 9 10

Axial

NEU

Calcification,

shows

barely

Vascular

discernible,

probable

physiologic, intracranial, vascular calcifications without lumenal narrowing arteries ED.

involving bilateral internal carotid

• Diabetes o Concentric nature in contrast to eccentric calcified atherosclerotic plaque • Saccular Aneurysm o Chunky or curvilinear mural calcifications o May appear as hypointense rim on MR • Fusiform Aneurysm, ASVD o Long segment irregular fusiform dilatation o Mural calcifications common Helpful Clues for Less Common Diagnoses • Chronic Renal Failure o Vascular calcification & arterial stiffness occurs due to disturbances of calcium metabolism • Cavernous Malformation o "Popcorn" appearance with hypointense hemosiderin rim on T2WI MR • Arteriovenous Malformation o Calcifications in 25-30% • Calcified Plaque Embolus o Calcified cerebral emboli change in site, size, & attenuation with time o Not a contraindication to thrombolysis • Hyperparathyroidism o Subsequent hypercalcemia can lead to vascular, soft tissue, & joint calcifications Helpful Clues for Rare Diagnoses • Mineralizing Microangiopathy o Deposition of calcium in small vessels of previously irradiated parenchyma o Most often occurs after combined treatment with chemotherapy & radiation

Atherosclerosis,

Axial NEeT shows supracJinoid internal

Intracranial

eccentric calcificaUon of carotid arteries bilaterally

associated with lumenal narrowing.

the

VASCULAR CAlCiFICATlON(S)

Diabetes

Saccular Aneurysm (Left) Axial NECT shows concentric arterial wall calcifications of the basilar artery ~ In the correct clinical selling this is not a pathognomic but a presumptive diagnosis of diabetes. (Right) Axial NEeT shows chunky & curvilinear wall calcification I:]] of a basilar tip aneurysm. There is also subarachnoid hemorrhage in the basal cisterns 81 following rupture.

(Leh) Axial NECT shows rim calcification of a large fusiform basilar artery aneurysm ~ Also note classic atherosclerotic eccentric

internal

carotid

&

MCA calcifications (Right) Axial NECT demonstrates a calcified cortical/subcortical mass in the left cerebral hemisphere I:] of a cavernous malformation.

(Leh) Axial NECT demonstrates an acute right MCA stroke secondary to an acute calcified plaque embolism 81. (Right) Axial NEeT shows extensive calcifications of mineralizing microangiopalhy from prior radiation therapy and chemotherapy with involvement of the basal ganglia and subcortical white

-=

maller.

I 9 11

SEClrlON 18 Veins, Venous Sinuses Anatomically Based Differentials Dural Sinus Lesion, General Enlarged Cortical Veins Enlarged Deep (Medullary/Ependymal) Veins Unilateral Cavernous Sinus Mass Bilateral Cavernous Sinus Lesions Meckel Cave Lesion

Modality-Specific Hyperdense Dural Sinus

1-10-2 1-10-8 1-10-10 1-10-14 1-10-18 1-10-22

Imaging Findings 1-10-26

DURAL SINUS LESION, GENERAL

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DIFFERENTIAL DIAGNOSIS Common • Arachnoid Granulations, Dural Sinuses • Dural Sinus Hypoplasia-Aplasia • Thrombosis, Dural Sinus • Dural A-V Fistula Less Common • Meningioma • Metastasis • Lymphoma • Depressed Skull Fracture • Intracranial Hypotension Rare but Important • Dural Venous Sinus Stenosis • Thrombophlebitis • Polycythemia • Hemangioma • Leukemia • Rosai-Dorfman Disease • Extramedullary Hematopoiesis • Lipoma • Masson Vegetant Intravascular Hemangioendothelioma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Includes generic lesions affecting ALLdural venous sinuses o Cavernous sinus (CS) unique because of contents, proximity to skull base o Has diagnoses (e.g., perineural metastasis, aneurysm, schwannoma) that do not affect other sinuses • Imaging challenge: Differentiate dural sinus thrombosis (DST) from stenosis, anatomic variants o CTV best o MRV shows anatomical narrowing/occlusion o T2* (GRE/SWI) shows thrombus

I 10 2

• Transverse sinus (TS) most common site "Flow gaps" on MRV can mimic DST • Confirm "flow gaps" on source data • No "blooming" thrombus on T2* • If MRV is unclear, CTV helpful • Thrombosis, Dural Sinus o Symptoms vary with extent of thrombus, collaterals, cortical vein involvement o NECT • Hyperdense clot in sinus • Cortical/subcortical hemorrhages (bilateral parasagittal if superior sagittal sinus or temporal lobe if vein of Labbe) • ± Edema (vasogenic > cytotoxic) o CECT shows "empty delta sign" o

Helpful Clues for Common Diagnoses • Arachnoid Granulations, Dural Sinuses o Can be large (> 1 cm), remodel calvarium • May narrow but not occlude sinus o Round/ovoid, well-circumscribed o CSF density/signal intensity • Dural Sinus Hypoplasia-Aplasia o Seen in up to 1/3 of normal scans

o

MR

• Loss of normal "flow void" • Clot elongated, fills sinus, shows susceptibility on T2* • Confirm with MRV o Chronic thrombosis difficult diagnosis • Progressive recanalization &/or granulation tissue forms • Chronic thrombus enhances, mimicking patent dural sinus • Dura also thickens, enhances; bizarre-appearing collaterals may mimic vascular malformation • May have clinical, imaging findings of intracranial hypertension (pseudotumor cerebri) • Dural A-V Fistula o Most acquired; clinical manifestations vary • Pulsatile tinnitus, exophthalmos • Less common = progressive encephalopathy (dementia), diffuse white matter hyperintensity from chronic venous hypertension o Imaging • Flow voids within wall of thrombosed dural sinus common • High grade lesions prone to intracranial (usually parenchymal) hemorrhage • Small web of vessels on collapsed MRA images may suggest diagnosis • DSA gold standard for diagnosis Helpful Clues for Less Common Diagnoses • Meningioma o Enhancing dural-based mass ± "tail" o May invade, occlude, or compress dural sinuses

DURAL SINUS

LESION,

GENERAL

CIl

"

c:

Bony hyperostosis variable Metastasis o Systemic primaries may compress or invade dural sinuses o Usually arise from calvarium with secondary dural involvement Lymphoma o Dural-based mass(es) common in metastatic lymphoma Depressed Skull Fracture o May lacerate/compress/occlude dural sinus o ± Venous epidural hematoma (EDH) o Venous EDH develops slowly, presents late! Intracranial Hypotension o Dural venous engorgement, enhancement o Slumping midbrain, tonsillar descent, SDHs

•

•

•

•

Helpful Clues for Rare Diagnoses • Dural Venous Sinus Stenosis o Focal short segmental narrowing on CTV, MRV, or DSA (venous phase) o May cause intractable headaches (intracranial hypertension) o Patients with suspected symptomatic venous outflow restriction, pressure gradient at venography may improve after stent • Thrombophlebitis o Complication of infection (meningitis, rhinosinusitis, or mastoiditis) o Infection spreads easily due to valveless nature of intracranial venous system

Arachnoid

Granulations,

May cause septic venous thrombosis Polycythemia o High hematocrit - "dense" dural sinus Hemangioma o Capillary/cavernous vasoformative neoplasm o Convexity dura or venous sinus (CS most common) o May present with mass effect or intracranial hypertension Leukemia o Dural-based enhancing masses o May compress/invade dural sinuses Rosai-Dorfman Disease o Younger patients o Lymphadenopathy> para nasal sinus disease o Lymphadenopathy usually coexists if C S disease is present o Solitary/multiple dural-based enhancing masses Extramedullary Hematopoiesis o Dural-based enhancing masses o Dural sinus compression/invasion rare Lipoma o Fat in dural sinus rare; CS most common Masson Vegetant Intravascular Hemangioendothelioma o Rare benign tumor of young patients o Papillary endothelial hyperplasia o Can cause stenosis, hypertension o Can mimic meningioma o

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Dural Sinuses

I Axial T2WI FS

= ~

MR

shows

in the righllranSVerse probably

represenUng

a

large ovoid

CSF-signal mass

sinus with internal "flow vein.

void"

Axial

T1 C+ FS MR in the same patient

shows that the

lesion E:II does not enhance and is the same signal as CSF. Vein ~

enhances.

in an asymptomatic

This was an incidental

patient.

10

finding

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DURAL SINUS LESION, GENERAL

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Arachnoid Granulations,

Dural Sinuses

(Left) Axial erCT shows hypodense CST-like lobulated filling defect in the

right transverse sinus

=.

Note adjacent calvarial scalloping ~ (Right) Axial bone CT in the same patient shows smooth, well-delineated erosion of the calvarium caused by arachnoid granulation.

Arachnoid Granulations,

Dural Sinuses

Arachnoid Granulations,

Dural Sinuses

Arachnoid Granulations,

Dural Sinuses

Arachnoid Granulations,

Dural Sinuses

(Left) Sagittal T1 WI MR shows a round fluid signal cystic lesion within the

superior sagittal sinus

= that

followed CSF on all sequences. This is a variant case because of the atypical size and location of the lesion. (Right) Coronal oblique angiography shows a large filling defect =:I in the superior sagittal sinus caused by giant arachnoid granulation.

(Left) Axial T2WI MR with video inversion shows a cluster of sharply marginated CSF-like cysts I2J remodeling the inner calvarium. (Right) Axial T2WI MR shows an arachnoid granulation that appears to communicate directly with the adjacent subarachnoid space via ~1 defect in its inner margin

I 10 4

along the inner table of the calvarium ~. It also contains a hypoinlense "knuckle" of tissue E:lthat forms an intraosseous meningoencephalocele.

DURAL SINUS

lESION,

en

GENERAL

c: "" III

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Co OJ .., III

(Left) Coronal MRV shows no flow-relaled signal wilhin the left transverse or sigmoid sinuses on lhe MRV MIP projection. Compare to normal dominant right transverse and sigmoid ~ sinuses. (Right) Coronal MRV shows flow-related signal within an asymmetrically smaller lefl transverse sinus it is

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important to review the source images before concluding lhatlack of flow on MIPs is genuine.

Thrombosis,

Dural Sinus

Thrombosis,

Dural Sinus (Left) Sagillal CTA shows that anterior 1/3 of superior sagittal sinus is patent E'J. Posterior 2/3 are filled with nonenhancing clOI (Right) Axial T2' CRE MR in

=.

the same patient shows II blooming" of clot in superior sagittal sinus EB Note extension into adjacent

cortical veins ~

Thrombosis,

Dural Sinus

Thrombosis,

Dural Sinus (Left) Laleral MRV shows lack of flow-relaled

enhancement in the

=

expected localion of lhe superior sagittal sinus consistent with acute lhrombosis. (Right) Axial T2WI MR shows bilateral parenchymal foci of swelling and high T2 signal in areas of associated cortical venous

ischemia

=

in the same

patient as the prior image. These findings are due to associated cortical venous occlusion.

I 10 5

DURAL SINUS

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LESION, GENERAL

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Dural A-V Fistula

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sigmoid sinus ~ with retrograde filling of transverse & contralaleral

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Dural A-V Fistula

(Left) Lateral angiography shows thrombosis at the of the transverse,

dural sinuses. Several enlarged lransosseous perforating branches from occipital artery supply dAVF ffi (Right) Axial T2WI MR shows normal right "flow void'l liB Left side is hyperintense and contains numerous

tiny" (Jow voids"

=.:I.

Dural AVF developed in chronically occluded left transverse sinus.

Meningioma (Left) Axial NECT shows a densely calcified meningioma that originated within and mildly expands superior sagittal sinus (Right) Coronal T1 C+ MR

=.

shows dural-based metastasis

=.:I on

both sides of superior sagittal sinus, which is invaded and thrombosed by the tumor E!1I.

(Leh) Sagittal T1 C+ MR shows an enhancing dural-based mass =.:I in the region of cisterna magna that is encroaching into the region of the torcular

herophili E!1I in a patient with systemic lymphoma. (Right) Axial NECT shows a large acute epidural hematoma due to a depressed skull fracture through the torcular and transverse sinus (not shown), resulting in dural sinus laceration and bleeding.

=

I 10 6

Metastasis

DURAL SINUS

lESION,

GENERAL III

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C.

III ., III

(Left) Coronal T7 C+ MR in this patient with intracranial hYPolensions shows engorged dural venous sinuses ~ thickened enhancing dura ~ Pituitary gland (not shown) also appeared enlarged. (Right) Axial MRV shows small caliber of both

transverse-sigmoid junctions,

sinus

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with focal stenosis

in the left transverse sinus

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=

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in a patienl with papilledema and headaches.

Thrombophlebitis (Left) Axial CECT shows bilateral proptosis. The

cavernous sinuses are enlarged with a lack of contrast

opacification

due to

thrombosis PJ:ll. Mucosal disease and fluid levels consistent with acute rhinosinusitis can be seen in multiple sinuses. (Right) Axial NECT shows hyperdense superior sagillal sinus ~ & cortical veins ~ and mimics CrCT in this 22 year old patient

with chronic

right-to-left cardiac shunt, hematocrit of 67.

(Left) Coronal T7 C+ MR in this /] year old shows a strongly enhancing left

=

cavernous sinus lesion encasing

the left internal

carotid artery

a",

extending

into sella and middle

cranial

fossa. (Right) Sagittal T7 C+ MR in another 73 year old with frontal 50ft tissue swelling shows dural, calvaria/ enhancing mass that occludes anterior

superior sagillal sinus PlB. Acute lymphoblastic leukemia was found.

I 10 7

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ENLARGED CORTICAL VEINS

DIFFERENTIAL DIAGNOSIS Common • Normal • Developmental Venous Anomaly • Arteriovenous Malformation • Dural A-V Fistula Less Common • Thrombosis, Dural Sinus • Thrombosis, Cortical Venous Rare but Important • Venous Varix • Vein of Galen Malformation • Sinus Pericranii

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Is there one enlarged vein or several? • Are they definitely veins? Could some be arteries? • Is there evidence of thrombosis? Helpful Clues for Common Diagnoses • Normal o Major anastomotic cortical veins (Trolard, Labbe, SMCV) can be very prominent • Developmental Venous Anomaly o Central vein of DVA can drain cortically o "Medusa head" configuration • Arteriovenous Malformation o Prominent cortical veins tend to be regional, geographically related to nidus o Look for varices, stenoses, stagnant flow

Normal

Caution: Prominent veins may persist even if no residual AV shunting present • Dural A-V Fistula o Chronic dural sinus thrombosis (vascularized thrombus) common precursor o Cognard type ITB shows reflux into cortical veins; types III-IV have direct cortical drainage • Hemorrhage risk t o

Helpful Clues for Less Common Diagnoses • Thrombosis, Dural Sinus o Thrombosis/stenosis causes increased back pressure o T2* (clot "blooms"), CECT or Tl C+ MR ("empty delta" sign) helpful • Thrombosis, Cortical Venous o Can occur without dural sinus occlusion o Hyperdense on NECT ("cord sign") o T2* most useful ("blooms") Helpful Clues for Rare Diagnoses • Venous Varix o Usually with AVM or dAVF o Isolated venous varices are rare • Vein of Galen Malformation o Deep veins but cortical may t if large • Sinus Pericranii o Transcalvarial communication between dural venous sinus, extracranial (scalp) veins o Sometimes associated with DVA

Developmental

Venous Anomaly

I 10 8

Axial Tl C+ MR shows symmetric prominenl enhancing comcal veins, right SlI larger than lelt 1:ll1. These are much larger than the other cortical veins PJ::I.

Lateral

digital

subtraction

angiography

with

3D

rendering shows classic DVA with "hair-like" difated medullary veins I:ll1 and large transcortical draining vein SlI. (Courtesy P.Lasjaunias, MOJ.

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ENLARGED CORTICAL VEINS

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arteriovenous

malformation

(not shown). (RighI) Axial TI C+ FS MR in a patient with righllransverse sinus dAVF shows reflux into very enlarged

cortical

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Dural Sinus

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vein of

Labbe EB (RighI) Axial T2* GRE MR shows thrombosed superior sagittal sinus ED with blooming clot extending into multiple enlarged cortical veins ~.

Vein of Galen Malformation

Sinus Pericranii (Lefl) Sagillal TI WI MR shows variant type of vein of Galen

malformation

with

enlarged vein of Galen ~ straight sinus Idl and innumerable dilated cortical veins (RighI) Lateral angiography shows paramedian venous anomaly from the sagittal sinus involves the sagittal sinus, calvarium, and scalp E!iilI in a patient with sinus pericranii.

I 10 9

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DIFFERENTIAL DIAGNOSIS Common • Developmental Venous Anomaly • Arteriovenous Malformation Less Common • Sturge-Weber Syndrome • Thrombosis, Deep Cerebral Venous • Thrombosis, Dural Sinus • Dural A-V Fistula • Glioblastoma Multiforme • Intracranial Hypotension Rare but Important • Capillary Telangiectasia • Blue Rubber Bleb Nevus Syndrome • Dural Venous Sinus Stenosis • Vein of Galen Malformation • Demyelinating Disease, NOS • Lymphoma, Intravascular (Angiocentric) • Encephalitis (Miscellaneous) • Granulomatous Angiitis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Urgent: Look for deep (i.e., internal cerebral) vein or dural sinus occlusion! • If not venous occlusion, consider o Could the lesion be a DVA? o Are there prominent cortical vessels as well? o Is there associated cortical abnormality?

I 10 10

Helpful Clues for Common Diagnoses • Developmental Venous Anomaly o Enlarged medullary veins o Drains into single dominant transcortical vein o Empties into dural sinus or deep ependymal vein o Solitary unless blue rubber bleb nevus syndrome o Hemorrhage rare unless associated with cavernous malformation • Arteriovenous Malformation o Parenchymal nidus, prominent cortical vessels o Enlarged medullary veins less common o Deep (subependymal) drainage associated with t hemorrhage risk

o

On Tl C+ small AVMs may appear as focal "blush" & draining vein

Helpful Clues for Less Common Diagnoses • Sturge- Weber Syndrome o Facial hemangioma ipsilateral to leptomeningeal (pial) angiomatosis o Paucity of normal cortical venous drainage causes chronic venous ischemia o NECT: Cortical Ca++, atrophy o CECTITl C+ MR • Enhancing pial angioma • Enlarged medullary veins • Enlarged choroid plexus ipsilateral to malformation common o FLAIRMR: "Ivy sign" of t sulcal signal • Thrombosis, Deep Cerebral Venous o Usually affects both internal cerebral veins (ICVs) ± vein of Galen (VaG), straight sinus (SS) o Initial findings may be subtle! o NECT • Hyperdense ICVs ± VaG, SS • Hypodense thalami, basal ganglia, ± deep white matter • ± Petechial hemorrhages o CECT • "Empty delta sign" if clotted SS, venous confluence • May see irregular "shaggy" enhancement around ventricles from engorged medullary veins oMR

• Tl: Deep veins iso- to hyperintense • T2: Hypointense clot may mimic "flow voids" • T2/FLAIR: Bilateral basal ganglia, thalami hyperintensities • T2* (GRE/SWI): Best sequence; clots "bloom" • Tl C+: Deep medullary veins may enlarge, enhance o DSA • Absent ICVs ± nonfilling of VaG, SS • Thrombosis, Dural Sinus o Chronic superior sagittal sinus occlusion medullary, ependymal veins enlarge as collateral venous drainage o Can mimic blue rubber bleb nevus syndrome • Dural A-V Fistula o Higher Cognard grades (IlB and above)

ENLARGED

DEEP (MEDULLARY/EPENDYMAL)

VEINS

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• Enlarged cortical> > medullary veins • Increased flow voids near or in dural venous sinus • Glioblastoma Multiforme a GBM, other malignant gliomas may develop necrosis, prominent neovascularity a Draining deep white matter (medullary, ependymal) veins may become very prominent • Intracranial Hypotension a Orthostatic headaches a Look for "sagging" floor of 3rd on sagittal, tonsillar herniation a Passive dural venous congestion common; medullary/deep ependymal vein enlargement less common Helpful Clues for Rare Diagnoses • Capillary Telangiectasia a Large capillary telangiectasia (typically> 1 cm) may have prominent central draining vein a Best seen on Tl C+ scan a Becomes hypointense on T2* (GRE/SWI) images • Blue Rubber Bleb Nevus Syndrome a Multiple cutaneous (bluish venous "blebs"), GI hemangiomas a Diverse CNS vascular malformations, venous variants common • Multiple DVAsclassic • Variant: Sinus pericranii & multiple DVAs

• Dural Venous Sinus Stenosis a Patients often have undiagnosed source of severe chronic recurrent headaches a Increased collateral flow, venous prominence, variable t ICP • Vein of Galen Malformation a Infant/child with dilated VOG a Enlarged ICVs, ependymal veins> > medullary veins • Demyelinating Disease, NOS a Fulminant demyelinating disease • Causes acute perivenular inflammation • Increased blood flow, loss of normal BBB a MS, ADEM, acute necrotizing/hemorrhagic leukoencephalopathy variants a Enhancement of deep medullary veins may be very prominent • Lymphoma, Intravascular (Angiocentric) a Clinical presentation • Stroke-like symptoms • Less common: Dementia, progressive mental status decline a Intravascular tumor plugs ± extension into perivascular spaces a Punctate, linear enhancing foci • Encephalitis (Miscellaneous) a Parenchymal T2/FLAIR abnormality ± mild-moderate enhancement • Granulomatous Angiitis a Enhancing foci ± mass effect a May have striking deep perivenular enhancement

Developmental

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I Axial T1 C+ MR shows prominent medullary tribularies ~ of deep OVA. Prominenl septal, internal cerebral, subependymal roof veins 81 drained lesion. This was an incidenlal finding.

Ulleral 3D OSA shows a classic deep OVA. Oi/aled medullary veins ~ drain into enlarged deep subependymaJ veins ~ and from there into internal cerebral vein 81. (Courtesy P.Ulsjaunias, MO).

10 11

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(Left) Axial T I C+ MR haws left parietal AVM wilh deep drainage into subependymal veins of lateral ventricle ~ NOle enlargement of choroid plexus glomus secondary to increased venous drainage_ (Right) Axial T1 C+ MR shows enhancing pial malformation

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enlarged left thalamo-slriale vein

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choroid

plexus IlI1 typical secondary findings in Slurge-Weber syndrome.

Thrombosis, (Left) Axial T1 C+ MR shows

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striking linear enhancement

in deep medullary veins secondary to venous stasis caused by bilateral ICV occlusion. (Right) Lateral angiography shows poor opacification of 555, with only a few irregular, small parasagitlal channels open

lCB Most venous drainage is occurring through massively enlarged medullary veins inlO prominent

subependymal

veins, ICV

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sinus shows prominent white

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matter "blushll with enlarged medullary. deep ependymal veins Ia. (Right) Axial T1 C+ MR shows an enhancing DVF wilh a subslantial band of phase-encoding artifact. There is a prominent left-sided enhancing basal vein •.

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I 10 12

Dural Sinus

ENLARGED

DEEP (MEDULLARY

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Intracranial Hypotension

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(Left) Axial T1 C+ FS MR shows enhancing necrotic right parieto·occipital mass with very prominent draining veins ~. Biopsy had dise/osed CBM. (RighI) Axial T1 C+ MR shows mild

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=

(Left) Coronal T1 C+ MR shows multiple linear enhancing foci along deep medullary veins and

perivascular spaces

=.

Biopsy proved intravascular lymphoma. (Right) Sagillal T1 C+ MR shows multiple linear enhancing foci in deep periventricular

cerebellum. biopsy-proven granulomatous

white matter

This is angiitis.

(Courtesy /. Pingree, MD).

I 10 13

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DIFFERENTIAL DIAGNOSIS

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Common • Pituitary Macroadenoma • Meningioma • Schwan noma • Metastases, Skull and Meningeal • Lymphoma, Metastatic, Intracranial • Nasopharyngeal Carcinoma Less Common • Saccular Aneurysm • Carotid-Cavernous Fistula, Traumatic • Thrombosis, Cavernous Sinus • Dermoid Cyst • Epidermoid Cyst • Neurosarcoid • Pseudotumor, Intracranial • Hemangioma Rare but Important • Plexiform Neurofibroma • Chordoma • Tuberculosis • Iatrogenic

ESSENTIAL INFORMATION

I 10 14

Key Differential Diagnosis Issues • Lateral dural walls of cavernous sinuses (CSs) should be flat or concave on axial/coronal imaging o Convex outer margin indicates abnormality o Lateral dural wall thick, easy to see; medial = thin, difficult to delineate • CSs are septated (not single pool of venous blood) • CSs enhance strongly but contain normal filling "defects" (Meckel cave, cranial nerves, ICA) • If mass present, is it intrinsic or extrinsic to cavernous sinus? • Where does mass originate? o Sella: Pituitary macroadenoma o Sphenoid sinus/central skull base: Metastasis, nasopharyngeal carcinoma o Dura: Meningioma, hemangioma, pseudotumor • Does it contain "flow voids"? o Aneurysm o

Dural AVF

Helpful Clues for Common Diagnoses • Pituitary Macroadenoma o Cavernous sinus invasion common with macroadenoma o Difficult to determine unless florid o Mass, gland indistinguishable (gland IS mass) • Meningioma o Diffusely infiltrates sinus, thickens dura o Lateral dural wall can sometimes be identified within thickened, intensely enhancing CS mass o Look for dural "tail" along clivus, tentorium o Look for other meningiomas (multiple meningioma syndrome) • Schwannoma o Most common = trigeminal, in Meckel cave o Typically well-marginated o Usually hyperintense on T2WI o Solitary> multiple (NF2) • Metastases, Skull and Meningeal o Three patterns • Hematogenous (direct or extension from skull base) • Perineural along cranial nerve (usually from nasopharyngeal or sinus tumor) • Direct geographic invasion (squamous cell, minor salivary gland tumors most common primaries) • Lymphoma, Metastatic, Intracranial o Primary CS rare; usually history of disease elsewhere • Nasopharyngeal Carcinoma o Two patterns • Direct cephalad extension into central skull base, CS • Perineural extension into cavernous sinus(es) along CNV2 Helpful Clues for Less Common Diagnoses • Saccular Aneurysm o Can be spontaneous, post-traumatic (pseudoan eu rysm) o Can be patent or partially thrombosed o Prominent "flow void", pulsation (phase) artifact • Carotid-Cavernous Fistula, Traumatic o Superior ophthalmic vein enlarged o ± Basilar skull fracture

UNILATERAL CAVERNOUS

SINUS MASS

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Usually at junction of vertical, horizontal ICA segments Thrombosis, Cavernous Sinus o onenhancing thrombus, thickened enhancing dural walls o May be secondary to sinusitis (thrombophlebi tis) o Superior ophthalmic vein(s) often enlarged o Proptosis common Dermoid Cyst o Typically in Meckel cave, not CS proper o Fat density/signal intensity Epidermoid Cyst o Typically in Meckel cave, not CS proper o CSF density/signal intensity o Usually occurs as extension from CPA lesion Neurosarcoid o Can be uni- or bilateral o Look for thickened infundibular stalk, dural masses Pseudotumor, Intracranial o Un i- > bilateral o Typically extends posteriorly from orbital apex into CS o Extensive dural enhancement along middle fossa can be present o Occasionally can be invasive, destructive; mimics neoplasm or aggressive infection Hemangioma o True vasoformative neoplasm in CS, dura o May mimic meningioma o

•

•

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Helpful Clues for Rare Diagnoses

• Plexiform Neurofibroma o Occurs only in NFl o Involves cutaneous, orbital branches of CNS

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into the left cavernous sinus lCB

displacing and

encasing the cavernOUSinternal carotid artery Eli:I. The tumor laleralto the ICA I:] confirms CS invasion.

Axial TI C + FS M R shows meningioma 01 the right cavernous sinus with thickening along both sides of the lateral dural waif Eli:I and effacement 01 the internal archilecture comparecllo the norma"ell side!:l:.

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10 15

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Schwannoma

Lymphoma, Metastatic, (Left) Axial T7 C+ FS MR in patient with non-Ilodgkin lymphoma who presented with left-sided facial weakness shows an enhancing mass along the maxillary division of CNS in the cavernous sinus extending into the apex of the pterygopalatine fossa 81. (Right) Axial TI C+ FS MR shows nasopharyngeal

=-

carcinoma

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spreading

into the

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c/;vus the left cavernous sinus/Meckel cave and intracavernous carotid artery wall~

fLeft) Axial CTA in a man with a headache, remole history of MVA sho\Vs a partially calcified right cavernous carotid artery pseudoaneurysm =:II. fRight) Axial CECT shows prominent orbital vessels =:II and a markedly enlarged right superior ophthalmic vein ~ in a patient with trauma and right-sided proptosis. The righl cavernous sinus is also distended, showing abnormal enhancement m.

I 10 16

Metastases, Skull and Meningeal

(Left) Axial T I C+ MR shows a classic trigeminal schwannoma in the right Meckel cave 81. Compare with the normal left side !:l:l. Schwannomas are typically hyperintense on T2WI, enhancing strongly. (Right) Coronal TI C+ FS MR shows a unilateral cavernous sinus metastasis m.

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Nasopharyngeal

Carcinoma

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CAVERNOUS

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(Left) Axial TI C+ FS MR in a patient with acute sphenoid sinusitis shows a unilateral nonenhancing clot in the right CS 8l a thrombosed cavernous ICA and early cerebritis in the adjacent brain ~. (RighI) Axial TI WI MR shows a dermoid cyst in the right Meckel cave and cavernous sinus Compare to the normal CSF-filled left Meckel cave

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81.

(Left) Axial TI C+ MR in

woman

with

headache,

nausea, and vomiting shows thickened dura along the left cavernous sinus Ill. SymplOms and findings resolved quickly after IV steroids. (Right) Axial TI C+ MR shows a clival chordoma 81 with extension into the left cavernous sinus ~. The right cavernous sinus, including the Meckel cave

=.. is normal.

I 10 17

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SINUS

LESIONS

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DIFFERENTIAL DIAGNOSIS Common • Pituitary Macroadenoma • Meningioma • Metastasis, Skull Base • Lymphoma, Metastatic, Intracranial Less Common • Neurofibromatosis Type 2 • Carotid-Cavernous Fistula • Thrombosis, Cavernous Sinus • Chordoma, Clivus • Plasmacytoma • Neurosarcoid • Langerhans Histiocytosis, Skull Base Rare but Important • Pseudotumor, Intracranial • Leukemia • Extramedullary Hematopoiesis • Germ Cell Neoplasms • Erdheim-Chester Disease • Benign Nonmeningothelial Tumors

ESSENTIAL INFORMATION

I 10 18

• Variable extension into CS proper Look for "dural tail" (thickening along tentorium, middle fossa) o Look for obliteration of CSFin Meckel caves o May extend inferiorly along clivus • Metastasis, Skull Base o Permeative, destructive mass • Hematogenous spread from extracranial primary common (e.g., breast) • Most commonly centered in central skull base (BaS), secondary extension into CS • May also be direct geographic extension from nasopharyngeal carcinoma o CS involvement can be uni-, bilateral; symmetric or asymmetric o Sagittal TI, coronal TI C+ FS scans useful • Lymphoma, Metastatic, Intracranial o Primary central BaS lymphoma rare o Uni- > bilateral o Isointense, avidly enhancing o Associated cranial nerve, meningeal (dural) lesions common o Tumor often surrounds, encases but does not occlude cavernous ICAs o

Helpful Clues for Less Common Diagnoses • Neurofibromatosis Type 2 o Multiple schwannomas, meningiomas • Most common CS schwannoma = trigeminal (Meckel cave) • Look for meningiomas of CS, optic nerve sheath, tentorium o Look for bilateral vestibular schwannomas (YS, diagnostic of NF2), evidence for prior CPA/temporal bone surgery • One YS + other schwan noma, meningioma highly suggestive • Carotid-Cavernous Fistula o Uni- > bilateral carotid-cavernous fistulas o Look for CS "flow voids" in addition to ICAs o Look for t superior ophthalmic vein(s) (SOY) • CTA helpful screening study • DSAto delineate fistula site(s) • Thrombosis, Cavernous Sinus o Can be spontaneous, sterile, or septic (thrombophlebitis) • Look for infection in paranasal sinuses, orbits

BILATERAL CAVERNOUS Nonenhancing areas within intensely enhancing CS • Lateral dural wall, CS septations enhance, thrombus does not • Look for t SOVs Chordoma, Clivus o Destructive T2 hyperintense mass centered in clivus o Large lesions may invade CS • Displace but rarely occlude ICAs o Chondrosarcoma may mimic • Usually unilateral, arises from petro-occipital fissure Plasmacytoma o Solitary destructive mass of central BOS • Centered in sphenoid sinus, clivus • Isointense, strongly enhancing mass • Bi- > unilateral Neurosarcoid o CS rare site o Look for other lesions • Pituitary, infundibular stalk lesion • Cranial nerve involvement • Dural-based masses o Infiltrating CS mass(es) • Lesions enhance strongly, uniformly • Bone destruction rare Langerhans Histiocytosis, Skull Base o Osteolysis with sharply defined scalloped margins ± soft tissue mass o Varies from small punched out lesion to widespread diffuse bony involvement • May destroy almost entire BOS o Homogeneous enhancement o

•

•

•

•

SINUS

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Helpful Clues for Rare Diagnoses

• Pseudotumor, Intracranial o 90% of intracranial pseudotumors occur without orbital disease o Tolosa-Hunt syndrome (painful ophthalmoplegia) when CS involved • Uni- > bilateral • Look for associated meningeal thickening (can be extensive) • Bone invasion, destruction may occur • Leukemia o Paranasal sinus/orbit involvement typical o Bilateral CS involvement rare • Extramedullary Hematopoiesis o CS involvement rare o Look for associated dural-based masses (calvarium, spine) • Germ Cell Neoplasms o Rare; typically involve pituitary gland/stalk • Erdheim-Chester Disease o Rare non-Langerhans cell histiocytosis o Disseminated xanthogranulomatous infiltrative disease of unknown origin o Adults> children o Long bones> brain, CS, orbits (rare) • Benign Nonmeningothelial Tumors o Benign cartilaginous tumors may arise from central BOS o If large, extend intracranially into CS

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I Coronal T1 WI MR shows a large macroadenoma with the "figure-of-eight" configuration, extension into the

suprasellar cistern and both cavernous sinuses aD.

rs

Axial T1 C+ MR shows a strongly enhancing central skull base mass extending laterally into both cavernous sinuses l:l1. A histologically typical meningioma was lound at surgery.

10 19

BILATERAL CAVERNOUS

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Intracranial

(Left) Axial T7 C+ FS MR shows a classic case of nasopharyngeal carcinoma extending superiorly into the sphenoid sinus, clivus, and cavernous sinuses The left Meckel cave is involved while the right BI is spared. (Right) Axial T7 C+ MR shows an extensive, destructive central skull base mass that infiltrates the sphenoid sinus and both cavernous sinuses The

=.

=.

mass encases both cavernous

carotid arteries

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Neurofibromatosis (Leh) Coronal T 1 C+ FS MR shows schwannomas in both Meckel caves Bilateral vagal schwannomas are also present~. (Right) Axial T2WI MR shows numerous abnormal II (Jow voids II, predominately in the left ~ but also the right cavernous sinuses, in this patient with red eye, proptosis 2 weeks following head trauma.

=.

=

(Left) Axial T7 C+ MR shows bilateral cavernous sinus thrombosis, resulting as a complication of acute sinusitis. Note nonenhancing areas within the cavernous sinus thickened enhancing dura of tentorium and sphenoid wings BI. (Right) Coronal T2WI MR shows a large dival chordoma with bilateral

=

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cavernous

I 10 20

sinus invasion

S.

Type 2

Carotid-Cavernous

Fistula

BILATERAL CAVERNOUS

SINUS

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Neurosarcoid (Left) Axial T2WI FS MR shows isointense central skull base mass that extends superiorly into the sella turcica and both cavernous sinuses (Right) Coronal T1 + FS MR shows both Meckel caves Iilled with

strongly enhancing tissue

m.

Note that the infundibular stalk 81 and pituitary gland appear normal.

langerhans

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Skull Base

Pseudotumor,

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Intracranial ILeft) Coronal CECT shows a central skull base lytic lesion with sharply defined margins. A large 50ft tissue component invading skull

base, both cavernous sinuses, and nasopharynx P.:I enhances strongly and uniformly. (Right) Axial T1 C+ MR shows bilateral cavernous sinus enhancement left more striking than right, in a patient with left-sided cranial neuropathies. Symptoms resolved with the administration of steroids.

leukemia

Germ Cell Neoplasms (Left) Axial T2WI MR shows a leukemic mass in the right orbit !::l infiltrating the lacrimal gland and the superior reclus muscle ~ Note isoinlenS€ tissue in

both cavernous sinuses ~ suggesUng extension of leukemic infiltrate. (Right) Coronal CECT shows an enhancing mass infiltrating the pituitary gland 81 and both cavernous sinuses

=.

I 10 21

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• Schwannoma, Trigeminal, Intracranial • Meningioma • Metastasis, Skull Base less Common

• • • • • • •

Metastasis, CSF/Meningeal Metastasis, Perineural CNV3 Meningitis Neurosarcoid Neurofibroma Pseudotumor, Intracranial Pituitary Macroadenoma

Rare but Important

• • • • • • •

Metastasis, Perineural CNV2 Trigeminal Herpetic Neuritis Lipoma Epidermoid Cyst Dermoid Cyst Neurocysticercosis Chronic Thrombosis, Dural Sinus

---

ESSENTIAL INFORMATION

Key Differential

I 10 22

• Acute muscles • Chronic muscles

DIFFERENTIAL DIAGNOSIS

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Diagnosis Issues

• Normal Meckel cave (Me) o Anatomy • CSF-filled, dura-arachnoid lined invagination into cavernous sinus (CS) • Contains CNS fascicles, semilunar ganglion • Communicates directly, freely with prepontine/cerebellopontine cisterns o Normal imaging • Ovoid, smooth CSF-filled cisterns on axial, coronal scans resemble "open eyes" • Bilaterally symmetric hypointensity on TlWI • Bilaterally symmetric hyperintensity on T2WI • Abnormal Meckel cave o "Winking" Meckel cave sign • One MC filled with soft tissue, not CSF • One MC therefore NOT = CSF density /intensity • Asymmetric appearance = "Winking" Meckel cave (one "eye" appears closed) o Look for CNS motor denervation secondary to MC mass • May be only sign of subtle lesion

hyperintensity, enhancement of of mastication - atrophy, fatty infiltration of of mastication

Helpful Clues for Common

Diagnoses

• Schwannoma, Trigeminal, Intracranial o Variable configuration • "Dumbbell" tumor with CPA component, constriction of tumor at entrance to Meckel cave, Meckel cave mass • May involve MC only • ± Extracranial extension along VI, V2, &/or V3

Unilateral unless NF2 o Hyperintense on T2WI, strong enhancement on TI C+ o May result in atrophy of muscles of mastication • Meningioma o Uni- > bilateral involvement o Dural thickening along cavernous sinus, tentorium (dural "tail sign") o ± Ipsilateral denervation, atrophy of muscles of mastication • Metastasis, Skull Base o Metastases to Meckel cave can be hematogenous, direct geographic extension, perineural, or CSF spread • Hematogenous spread to central skull base (BaS) with secondary involvement of cavernous sinus • Direct extension from extracranial primary (e.g., nasopharyngeal squamous cell carcinoma) into central BaS • Uni- > bilateral involvement o Sagittal Tl WI helpful • Look for replacement of normal fatty clival marrow ± cortical destruction o

Helpful Clues for less Common

Diagnoses

• Metastasis, CSF/Meningeal o Pia-arachnoid tumor spread may extend into MCs o ± Enhancement along cisternal CNS • Metastasis, Perineural CNV3 o Retrograde tumor spread along mandibular nerve o Look for mass in retromolar trigone, masticator space o Adenoid cystic carcinoma, squamous cell carcinoma most common

CJl

MECKEL CAVE LESION

'"

c:

CNV3 appears thick, enhancing ± erosion of foramen ovale • Meningitis o Any etiology (e.g., pyogenic, TB) o Dura-arachnoid disease can extend into o

MC o Look for basal cistern enhancement • Neurosarcoid o Pituitary gland, infundibular stalk, dural masses common o Can be uni- or bilateral • Neurofibroma o Orbit/scalp/lid plexiform in NFl o May extend posteriorly through SOF, infiltrate VI branches - MC • Pseudotumor, Intracranial o Typically originates in/around orbit o Extends through SOF into CS, MC o Variable dura-arachnoid thickening, enhancement o Idiopathic invasive subtype • May erode bone, mimic aggressive infection, neoplasm • Pituitary Macroadenoma o Can extend into one or both CSs, MCs o Pituitary gland generally cannot be distinguished from mass o Gland IS mass o Aggressive invasive type may destroy central skull base, clivus • Pituitary adenoma> > > > carcinoma • Can mimic malignant disease, so do endocrine workup

ll>

Helpful Clues for Rare Diagnoses • Metastasis, Perineural CNV2 o Often skin carcinomas (basal, squamous cell) o Infiltrates along inferior orbital canal o May enlarge/erode foramen rotund urn o Thickened, enhancing maxillary nerve • Trigeminal Herpetic Neuritis .. o Herpes zoster oticus > trigeminal neuntls o Edematous, enhancing CNS • Ophthalmic division most commonly involved • Lipoma o MC is rare site o Uni- > bilateral • Epidermoid Cyst o May originate in MC or as extension from CPA epidermoid o Does not suppress on FLAIR;restricts on DWI • Dermoid Cyst o Looks like fat in MC, not CSF o May occur with or without rupture, CSF fatty droplets • Neurocysticercosis o Cysts in basal cisterns may extend into one or both MCs • Chronic Thrombosis, Dural Sinus o Chronically occluded dural sinus(es) o Dural thickening, enhancement secondary to collateral venous drainage o May involve one or both MCs

::] Q.

..,

OJ ll>

::]

<

(1)

:J (f)

< (1)

:J

o C (f)

CJl

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I Coronal T2WI MR shows a classic "winking Meckel cave sign". The normal (right! Meckel cave is CSF-filled, hyperintense 81. The left side is filled with a mass that is hypointense and expands the Meckel cave

=.

Coronal T7 c+ MR in the same patient shows that the normal Meckel (right! is CSF-filled and hypointense 81 on this sequence. Contrast this with the enhancing mass that fills the left Meckel cave

=.

10 23

MECKEL CAVE LESION

(J) Q) (J)

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CIJ (J)

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II) "t:J C III

(Left) Coronal T1 C+ MR shows a meningioma in the right Meckel cave =:I. The left Meckel cave is filled with CSF E!:II as is normal. (Right) Axial T1 C+ MR shows a metastasis 10 the left petrous apex that extends in10 the clivus and the left Meckel cave =:I. The right Meckel cave B is normal and CSF-filled.

Metastasis, CSF/Meningeal (Left) Axial T I C+ FS MR in patient with diffuse CSF spread of glioblastoma multiforme shows pial

metastases covering the cerebellum~. The tumor has spread into the left Meckel cave =:I. Note the normal in the right Meckel cave E!:II. (Right) Coronal T I C+ FS MR shows perineurallumor extension of squamous cell carcinoma from the masticator space E!:IIthrough an enlarged foramen ovate ~ into the left cavernous sinus and Meckel cave =:I.

csr

Neurosarcoid (Left) Coronal T1 C+ MR shows basilar and cisternal meningitis with thickened, enhancing meninges and extension into the right Meckel cave ~. (Right) Coronal T1 C+ FS MR shows a sarcoid infiltrating the pituitary gland E!:II as well as both Meckel

=

caves

I 10 24

=.

,..c:

Ul

MECKEl CAVE LESION

Ql

:J C.

...

tll Ql

Metastasis, Perineural CNV2 (Left) Axial TI C+ MR shows an enhancing lesion in left cavernous sinus & Meckel cave l:ll. Thickened dura, enhancing pituitary gland, & infundibulum (not shown)

were also present. Symptoms, findings resolved after steroids. (Right) Axial C[CT w!curved reformatted image shows cheek melanoma l:ll spreading along left CNV2 from infraorbital foramen through inferior orbital canal !J::l & foramen {alundum ~ into Meckel cave B1. (Courtesy 5. van der Westhuizen, MO).

:J

<

~. :::J

(j)

< CD :::J

o

c: (j)

Ul :::J

c: (j)

CD

(j)

(Left) Axial TI C+ MR shows an enhancing right CNS l:ll extending into the Meckel cave. The left trigeminal nerve BI and Meckel cave appear normal. (Right) Axial T2WI MR shows an epidermoid in the upper CPA cistern wrapped around CNS, extending into the right Meckel cave l:ll. The epidermoid cyst is slightly hyperintense to CSF in the normal left Meckel cave B1.

Dermoid Cyst

Chronic Thrombosis, Dural Sinus (Left) Axial N[CT shows a fat-I.ike lesion in the right Meckel cave found incidentally in a patient with a headache after trauma. MR discf.osed a ruptured dermoid cyst with multiple fat droplets in the CSF cisterns. (RighI) Coronal TI C+ MR in a patient with multiple chronically

occluded venous sinuses shows dural l:ll and Meckel cave B engorgement caused by collateral venous drainage pathways. (Courtesy M. Castillo, MO).

I 10 25

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en ::J o c:: OJ

> en c:: OJ

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lD

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(f)

HYPERDENSE

DIFFERENTIAL DIAGNOSIS Common • Physiologic Hyperdensity • Thrombosis, Dural Sinus • Polycythemia • Subdural Hematoma, Acute (Mimic) less Common • Lymphoma, Metastatic, Intracranial • Metastases, Skull and Meningeal • Meningioma Rare but Important • Hemangioma • Leukemia • Extramedullary Hematopoiesis (Mimic) • Masson Hemangioma

ESSENTIAL INFORMATION

I 10 26

Key Differential Diagnosis Issues • Evaluate density, configuration of dural sinuses o ALLdural sinuses appear slightly hyperdense compared to adjacent brain, CSF on NECT o Margins of dural sinuses typically flat or slightly concave • Density: Is "dense dural sinus" TOO dense? o Measure dural sinus density o Compare to internal carotid artery (as internal standard) o If too dense, is it thrombosis or polycythemia? • Dural sinus thrombosis (DST) > > polycythemia • Check hematocrit! • If any question, do CECT + CTV or MR + MRV (include GRE or SWI sequence!) • Look for nonenhancing thrombus • Configuration: Disrupted dural sinus, bulging dural sinus, irregular/lobulated dural sinus o Some neoplasms invade dural sinuses o Usually meningioma or metastasis o May appear hyperattenuating if densely cellular o May also cause dural sinus thrombosis (e.g., meningioma in superior sagittal sinus)

DURAL SINUS Helpful Clues for Common Diagnoses • Physiologic Hyperdensity o At hematocrit of 43 (normal) • Intravascular blood in arteries, veins, dural sinuses appears slightly hyperdense compared to normal brain • At hematocrit of 70, circulating biood 63% denser o Dural sinuses appear especially dense in newborns because of • Physiologic polycythemia at birth • Unmyelinated/low density brain • Thrombosis, Dural Sinus o Many causes of DST o Trauma • May tear sinus • ± Thrombosis • Thin subdural hematoma can layer along falx, tentorium, mimic "empty delta sign" (latter seen on CECT, not NECT!) o Meningitis o Dehydration, hypovolemia • Shock, cardiac failure, other "low flow" states o Hypercoagulable states • Antiphospholipid antibody syndrome • Von Willebrand disease • Post-anticoagulation "rebound" phenomenon • Postpartum o Hormonal • Pregnancy, postpartum • Oral contraceptives o Hemoglobinopathies (e.g., sickle cell disease, thalassemia) o Vasculitis • Some vasculitides (e.g., Behc;:et)have propensity to cause DST • Polycythemia o Can be physiologic • Newborn • High altitude o Pathologic • Cyanotic congenital heart disease • COPD o ALLvessels (arteries, veins, dural sinuses) become hyperdense in polycythemia • t Hemoglobin protein - t dural sinus density • NECT in patient with polycythemia "looks like" a CECT

HYPERDENSE DURAL SINUS • Do not mistake for DST (MR + MRV clarifies) • Subdural Hematoma, Acute (Mimic) o May layer along tentorium, superior sagittal sinus ..• mimic dural thrombosis Helpful Clues for less Common Diagnoses • Lymphoma, Metastatic, Intracranial o Central skull base lymphoma may extend diffusely • Destroys bone • Infiltrates adjacent structures • May extend into one or both cavernous sinuses o Hyperdense, strongly enhancing • Metastases, Skull and Meningeal o Skull metastases commonly invade underlying dura o If adjacent to dural venous sinus, may extend into and compromise sinus • Meningioma o Expands into (or, less commonly, originates from) dural venous sinus o Grows slowly, so collateral blood flow develops o Sellar/parasellar/clival meningiomas commonly involve one or both cavernous sinuses Helpful Clues for Rare Diagnoses • Hemangioma o Capillary &/or cavernous hemangiomas may arise within dura o Cavernous sinus common site o May mimic meningioma

• Leukemia o Dural-based mass(es) along falx can mimic DST o Adjacent to, usually not within, venous sinus • Extramedullary Hematopoiesis (Mimic) o Dural-based mass(es) typical adjacent to, not within, venous sinus • Masson Hemangioma o Synonyms • Vegetant intravascular hemangioendothelioma • Intravascular papillary endothelial hyperplasia (IPEH) o Found in head, neck, fingers, trunk, occasionally viscera (liver) o Exuberant endothelial proliferation within veins, including dural venous sinus o Benign; can be mistaken for angiosarcoma

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CJ)

en c '" CJ)

CD

CJ)

Other Essential Information • Foreign body can mimic DST o Retained medical devices, catheters, bone cement, AVM glue, bullets, etc.

SELECTED REFERENCES 1.

2.

Teksam Met al: Frequency and Topographic Distribution of Brain Lesions in Pediatric Cerebral Venous Thrombosis. AJNR Am J Neuroradiol, 2008 Healy JF et al: Polycythemia mimicking venous sinus thrombosis. AJNR Am J Neuroradioi. 23(8):1402-3, 2002

I

=-

Coronal NECT in an asymptomaUc adult shows normal, slighdy hyperdense superior sagittal sinus falx

cerebri=.

-=

Axial NECT shows relaUvely hyperdense internal carotid arteries in a neonate. Note that the dural venous sinuses 81 also appear hyperdense. Low density of unmyelinated brain accentuates this appearance.

10 27

HYPERDENSE

(j) Q) (j)

DURAL SINUS

:::J C

C/) (j)

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o C

Thrombosis, Dural Sinus

Q)

> (j)

c

'Qi

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"ell "'C

c

C'Cl

(Left) Axial NECT in a premature

infant shows

striking hyperdensity of transverse sinuses II] caused by physiologic polycythemia of newborns and Jow density of adjacent, almost completely unmyelinated brain. (Right) Axial NECT shows a moderately hyperdense superior sagittal sinus 1m (contrast with normal mild hyperdensity). Note subtle effacement of the left frontal sulci E!l:I subarachnoid hemorrhage (later identified on FLAIR MR).

Thrombosis, Dural Sinus (Left) Axial NECT shows hyperdense, expanded straight sinus with convex margins The clot extends into the vein or Galen B torcular Herophili PJ::I. (Right) Axial NECT in the

=.

same patient shows hyperdense, expanded, somewhat lobulated-appearing superior sagillal sinus ICB clot in cortical

vein ~

("cord

sign").

(Left) Axial NECT looks like it is a contrast-enhanced scan. It isn't! The patient has a markedly elevated hematocri( which makes dura intracranial arteries, veins, venous sinuses I;] all appear hyperdense. (Right) Axial NEeT in the same patient shows striking hyperdensity of superior sagittal sinus caused by polycythemia (hematocrit = 70).

=

=

I 10 28

Thrombosis, Dural Sinus

HYPERDENSE

Ul

DURAL SINUS

'"c: III

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a. OJ ....• III

(Left) Axial NECT in a patienl with subdural hematoma shows mimic of thrombosed dural sinus. High densily blood is layered along the straighl sinus and falx ~ It also mimics lhe "empty delia sign" seen with OS!. which is idemified on CECT as enhancing dura

surrounding nonenhancing clol. (Right) Axial NEeT shows an acute right-sided subdural hematoma that has spread inlo interhemispheric fissure along lhe falx 81 and

=

tentorium

lymphoma,

Metastatic,

Intracranial

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Metastases, Skull and Meningeal (Left) Axial N[CT shows bilateral hyperdense masses in cavernous sinus in a patient with known systemic lymphoma who developed multiple cranial nerve palsies. Note suprasellar mass 81. MR showed extensive skull base infiltration~ cranial nerve

=

involvement.

(Right) Axial

NECT shows hyperdense sellar/suprasellar mass with left cavernous sinus extension ~ NK/T-cell lymphoma of pituitary gland that extends into cavernous sinus was found at surgery.

leukemia (Left) Coronal NECT shows hyperdense calcified mass involving central skull base, cavernous sinus, extending posteriorly along clivus and tentorium. Histologically typical

meningioma

was

found at surgery. (Right) Axial NECT shows mulliple hyperdense dural-based

masses

over convexity,

adjacent to falx and superior

sagittal sinus.

29

PART II Spine Trans-Spatial Craniovertebral Junction Vertebral Body - Posterior Elements Intervertebral Disc - Endplate Extradural Intradural-Extramedullary Intramedullary

SECTION 1

Trans-Spatial Anatomically Based Differentials Cervical, Chronic Post-Traumatic Abnormality Cervical, Lower, Post-Traumatic Bony Abnormality Thoracic Bony Trauma Lumbar Bony Trauma

11-1-2 11-1-4 11-1-6 11-1-8

Generic Imaging Patterns Scoliosis Kyphosis Kyphoscoliosis, Child Platyspondyly, Diffuse Sacral Mass, Adult Sacrococcygeal Mass, Pediatric Sacral Deformity

11-1-10 11-1-12 11-1-14 11-1-16 11-1-18 11-1-22 11-1-26

Clinically Based Differentials Acute Back Pain/Radiculopathy, Post-Operative Chronic Back Pain/Radiculopathy,Post-Operative Acute Upper Extremity Pain/Weakness Lower Extremity Pain Back Pain, Adult Back Pain, Pediatric

11-1-30 11-1-36 11-1-42 11-1-48 11-1-52 11-1-56

co

CERVICAL, CHRONIC

POST-TRAUMATIC

ABNORMALITY

~

Cl.

(fJ

U, c co

DIFFERENTIAL DIAGNOSIS

~

Common • Post-Traumatic o Accelerated Degeneration o Os Odontoideum o Post-Operative Spinal Complications o Kyphosis o Scoliosis o Ligament Ossification • Trauma Mimics o Ossification, Anterior Longitudinal Ligament o DISH o Post-Operative Change, Normal o Pathologic Vertebral Fracture o Rheumatoid Arthritis, Adult o Juvenile Idiopathic Arthritis o Craniovertebral Junction Variants o Klippel-Feil Spectrum o OPLL o Achondroplasia

Ql

C C.

(fJ

less Common • Osteomyelitis, C1-C2 • Crystalline Arthropathies o Gout, calcium pyrophosphate deposition disease, hemodialysis arthropathy

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Single level &/or upper cervical degenerative disease suggests prior injury

Accelerated Degeneration

II 1 2

• Wide surgical decompression without fusion often yields unstable spine with secondary deformity • Ossification of anterior longitudinal ligament (ALL)known as DISH when> 4 adjacent levels affected o May see smaller foci of ossification due to trauma, aging, or seronegative arthropathy o Look for other signs of trauma to help make distinction o Small foci of ossification ALLdistinguished from trauma by normal configuration of underlying vertebra • Posterior element injuries not uncommonly missed acutely o Malalignment, focal degenerative disease signs suggest prior injury • Fracture nonunion sometimes difficult to determine o Prolonged failure of bridging callus • Time to healing depends on age, health, and fracture location o Sclerosis of apposing fracture margins • Craniocervical instability due to multiple causes o Trauma o Arthritis: Rheumatoid arthritis, seronegative, calcium pyrophosphate deposition disease o Congenital: Achondroplasia, trisomy 21 o Infection • Kyphosis, scoliosis due to many causes o Short curve deformities suggest trauma, infection, congenital, or tumor

Os Odontoideum

Sagittal oblique T2WI MR shows 2S year old man with

Sagittal NEeT shows nonunited dens fracture ~

fXJsHraumatic disc degeneration arthritis. Chronic facet subluxation

odontoideum) and posHraumatic PLL ossification Ea. Pseudarthrosis in DISH -7 is a common finding and

= and uncovertebraJ

unless oblique views are obtained.

~

is easily missed

does not necessarily indicate trauma.

(os

CERVICAL, CHRONIC

POST-TRAUMATIC

en

ABNORMALITY

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Ossification,

OJ

Anterior longitudinal ligament

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(Left) Sagittal STIR MR shows post-traumatic kyphosis and acce/eraled degeneralive disease. (Right) Laleral radiograph shows mature-appearing ossicle fell/O be degenerative in

en

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=-

origin, in anterior

longitudinal ligament of a 55 year old. Underlying vertebral contour is normal, excluding leardrop-Iype fracture.

Post-Operative Change, Normal

Rheumatoid Arthritis, Adult (Left) Sagillal NrcT shows normal post-operative appearance afler C2 corpec/Omy =:I and slrul graft E!lI placement posleriorly. (Right) Sagillal bone CT shows anterior occipul-C7 subluxation !:Jl and extensive bony erosions ~ Allhough C7-2 subluxation is more common in rheumatoid

arthrilis,

subluxation also occurs at this level and in lower cervical spine.

Juvenile Idiopathic Arthritis

OPll (Left) Lateral radiograph shows facet fusion at C2-3 =:I. Congenital fusion anomalies may have same appearance as }IA. fusions may involve

vertebral

bodies, posterior elements, or bOlh. (Right) Sagillal bone CT shows bulky ossification PLL >=:> as well as ALL =:I. Post-traumatic heterotopic ossificalion is usually limited to 1-2 levels in cervical spine.

II 1 3

CERVICAL, LOWER, POST-TRAUMATIC BONY ABNORMALITY

ro ro

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,

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DIFFERENTIAL DIAGNOSIS

ESSENTIAL INFORMATION

f0-

Common

Key Differential

al

• Subaxial Cervical Spine Fractures o Hyperflexion Injury, Cervical o Posterior Column Injury, Cervical o Burst Fracture, Cervical o Hyperflexion-Rotation Injury, Cervical o Lateral Flexion Injury, Cervical o Hyperextension Injury, Cervical o Hyperextension-Rotation, Cervical o Pathologic Vertebral Fracture o Shear Injury • Post-Traumatic Deformity o Accelerated Degeneration o Facet Arthropathy, Cervical o Kyphosis o Scoliosis • Nontraumatic Entities that Mimic Trauma o Ossification of Anterior Longitudinal Ligament o Metastases, Lytic Osseous o Rheumatoid Arthritis, Adult o Juvenile Idiopathic Arthritis o Klippel-Feil Spectrum o Post-Operative Change, Normal o Facet Arthropathy, Cervical o Incomplete Fusion, Posterior Element o Osteomyelitis, Pyogenic

• Evaluate for post-traumatic instability with flexion/extension views o Not accurate in 1st week after injury

c: '0. rn

Less Common

• Spondyloarthropathy,

Seronegative

Diagnosis Issues

Helpful Clues for Common

Diagnoses

• Signs of acute injury o Malalignment, focal kyphosis, or lordosis o Soft tissue swelling (not always present) o Fracture line • Signs of remote trauma o Cervical deformity o Single level facet osteoarthritis • MR very helpful in questions of acuity of injury, and distinguishing trauma from trauma mimics o Look for bone marrow edema on fluid sensitive sequences • Trauma mimics o Ossification of anterior longitudinal ligament: No bone donor site visible o Growth disturbance in congenital and childhood disorders o Infection: Vertebral end plates eroded o Metastatic disease • May see round or oval bone lesion, or involvement of entire vertebral body • Cortex destroyed not just disrupted as in trauma o Incomplete fusion shows smoothly contoured margins, unlike trauma

II 1 4

Lateral radiograph

shows

flexion

teardrop

fracture

=

due to anterior compression, and widened interspinous distance [;8 due to posterior distraction.

Coronal bone CT shows isolated articular pillar fracture I:llI of C7 due to lateral flexion injury. Although posterior column fractures may be isolated, search should be made for associated

fractures.

CERVICAL, LOWER, POST-TRAUMATIC

BONY ABNORMALITY

Hyperflexion-Rotation Injury, Cervical (Leh) Sagiltal bone CT shows loss of height of C7 verlebral body and relropulsed fragment ~ into canal indicating axial load (burst) injury. (Right) Laleral radiograph shows focal kyphosis indica ling flexion injury. Grade 1 anlerofislhesis and unilateral facel dislocation P al C5-6

=

indicate

rotational

component

of injury. C6

articular pillars are superimposed, but pillars of C5 and above levels are rotated; this is a key sign of rOlation

injury.

Pathologic Vertebral Fracture (Lefl) Sagittal bone CT shows hyperextension injury with small bony avulsion 81. I'yperextension teardrop fractures such as this are usually smaller than Ihose seen in hyperflexion injuries. Note fused levels above fracture (RighI) Lateral radiograph shows severe compression fracture of C5 81 due to multiple myeloma. All visualized vertebrae are oSleopenic, but no focal lesions are visible, a

=.

common

appearance

on

radiographs of diffuse spine myeloma.

Ossification of Anterior longitudinal ligament (Lefl) Lateral radiograph shows discontinuous ligamentous ossification 1m. Ossification is adjacent to vertebral bodies with normal contour, and no donor sites are visible. (Right) Axial N[CT shows enlarged spinal canal and dysplastic posterior elements. Clues lO nonlraumatic

etiology

are

smooth, corticated edges of bone defecls 81 and normal SOfllissues.

II 1 5

THORACIC BONY TRAUMA

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DIFFERENTIAL DIAGNOSIS Common • Fractures o Anterior Compression Fracture o Pathologic Vertebral Fracture o Lateral Compression Fracture o Chance Fracture o Burst Fracture o Facet-Lamina Fracture • Nontraumatic Fracture Mimics o Schmorl Node o DISH o Physiologic Wedging, Vertebral Body o Kyphosis, Idiopathic o Scheuermann Disease o Limbus Vertebra/Ring Apophysis o Sickle Cell o Osteomyelitis, Pyogenic Less Common • Trauma and Post-Traumatic Abnormalities o Fracture-Dislocation, Thoracolumbar Junction o Distraction Fx, Low Thoracic o Kilmmell Disease • Nontraumatic Fracture Mimics o Langerhans Cell Histiocytosis o Scoliosis and Kyphosis, Congenital o Renal Osteodystrophy o Achondroplasia o Osteomyelitis, Granulomatous o Cushing Disease

Anterior

Compression

Fracture

I I

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues • Important to distinguish between types of vertebral body fractures since treatment differs by type • Fractures most common at thoracolumbar junction • When one spine fracture is seen, always look for others Helpful Clues for Common Diagnoses • Anterior Compression Fracture o Never involves posterior vertebral body cortex or neural arch o Easily missed in upper T-spine on radiographs • Chance Fracture o Usually extends through posterior vertebral body cortex, but no retropulsed fragment o Horizontal fracture of posterior elements OR rupture of interspinous ligaments and facet joints • Burst Fracture o Always extends through posterior vertebral body cortex, may have retropulsed fragment o Vertical fracture of posterior elements also present • Scheuermann Disease o 4 or more levels involved; undulating end plates; normal anterior cortex

Burst Fracture

II 1 6

Sagillal NECT shows T4 compression fracture ~ and TS Chance fracture The degree of anlerior heighl loss and presence of horizontal posterior element fracture E!2 disunguish Chance fracture.

=.

Sagillal bone CT shows T3 bUN fracture wilh ret.ropulsed fragment Compression fractures are present at T4 and T5 r.:D. Patient is skeletally immature (nole ring apophyses ffi.

=.

THORACIC

BONY TRAUMA

(Left) Axial bone CT shows right T1 0 laminar fracture PJ::l associated with vertebral body fracture Chance injury. Facet (ractures may be isolated, but laminar fractures rarely are. (Right) Lateral radiograph shows mild anterior wedging T12 and L 1 81. Physiologic wedging may occur at T11-L7 and involves both endplates, while the anterior vertebral body cortex is

=-

normal,

(Left) Lateral radiograph shows thoracic kyphosis ~ without focal bony deformity. Idiopathic kyphosis probably originates as a postural problem but often becomes rigid. (Right) Sagiltal bone CT shows 4 adjacent vertebral bodies 81 affected

with anterior

wedging, undulating endplates, and Schmor/ nodes. These findings, especially combined with normal anterior vertebral

body cortices, are pathognomonic.

Fracture-Dislocation, Thoracolumbar Junction

Scoliosis and Kyphosis, Congenital (Left) Sagiltal bone CT shows ]-column fracture-dislocation.

=

Anterior

~ and posterior longitudinal ligament avulsions result in anterolisthesis of T6-7. Posterior column disruption is shown by spinous process fraclure

at T5

fractures

ffi

laminar

were also present

(not shown). (Right) Lateral radiograph shows focal kyphosis 81 at T10-11 due to vertebral body fusion. Diagnosis is readily made by CT or MR if radiographs are

II

equivocal.

1 7

ro ~ Cl. (/) , C/)

c

ro ~

Iell C

a.

(/)

LUMBAR

DIFFERENTIAL DIAGNOSIS Common • Fractures o Anterior Compression Fracture o Burst Fracture o Chance Fracture o Pathologic Vertebral Fracture o Facet-Posterior Fracture o Transverse Process Fracture • Fracture Mimics, Vertebral Body o Schmori Node o Physiologic Wedging o Limbus Vertebra o Scheuermann Disease o Scoliosis and Kyphosis, Congenital o Neurogenic (Charcot) Arthropathy o Sickle Cell o Osteomyelitis, Pyogenic o Post-Operative Spinal Complications • Fracture Mimics, Posterior Elements o Incomplete Fusion, Posterior Element o Spondylolysis o Post-Operative Change, ormal Less Common • Fracture and Post-Traumatic Abnormalities o Lateral Compression Fracture o Fracture-Dislocation o Ktimmell Disease o Insufficiency Fracture, Pedicle o Apophyseal Ring Fracture • Fracture Mimics o Renal Osteodystrophy o Achondroplasia Anterior

II 1

Compression

o

Osteomyelitis,

Sagittal bone CT shows fracture BI involving anterior and superior cortices of vertebral body; while sparing

Granulomatous

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Anterior Compression Fracture o Never involves posterior vertebral body cortex or neural arch o Unless osteoporosis, > 40% loss of height suggests Chance fracture, not compression • Burst Fracture o Extends through posterior vertebral body cortex o Usually but not always have retropulsion of fragment into spinal canal o Fractures of posterior elements vertically oriented • Chance Fracture o Often extends through posterior cortex o Always either horizontally oriented posterior element fracture OR widened interspinous distance due to interspinous ligament rupture • Transverse Process Fracture o Associated with retroperitoneal soft tissue injury, bony and ligamentous injury in pelvis • Physiologic Wedging o May be seen at Tll-Ll levels o Usually affects both superior and inferior endplates equally o No angular deformity of endplates or anterior cortex

Fracture

posterior cortex. Posterior elements are also intact

8

BONY TRAUMA

Burst Fracture

=

Sagittal bone CT shows involvement of posterior cortex which distinguishes this injury from compression

fracture.

LUMBAR BONY TRAUMA

Pathologic Vertebral

Fracture (Left) Sagittal NEeT shows anterior vertebral compression and horizontal fracture through posterior elements. In contrast, a burst fracture

has vertically

oriented posterior element fracture. (Right) Lateral radiograph shows L3 compression fracture Lytic bone lesion is not well

=.

seen, but anterior

displacement of aorta E2 due to sort tissue rnass points to pathologic fracture.

Schmorl Node

Limbus Vertebra (Left) Lateral radiograph shows multiple Schmorl nodes.' Shallow, smooth, bowl-shaped vertebral endplate depressions [;>J. Fractures are more angular in appearance. (Right) Lateral radiograph shows nonunited ring apophysis Sclerotic margins of apophysis and subjacent vertebral body are helpful signs to distinguish from chip fracture.

=.

Neurogenic

(Charcot)

Arthropathy

Sickle Cell (Left) Lateral radiograph shows chronic fractures with 1055 of height of L3 vertebral body I!:iJ and absence of anleroinferior

corner of L2

E2. There is clear instability, with widened facet joints. Sclerosis and extensive bone

=

debris are clues to diagnosis, as is patient history. (Right) Sagittal T2WI MR shows central depressions in vertebral endplates at multiple levels, the classic Lincoln log appearance reflecting bone II

infarcts.

/I

II 1 9

SCOLIOSIS

co

~ Cl. CIJ, (/)

c

co ~

IQl

c Q.

CIJ

DIFFERENTIAL DIAGNOSIS Common • Scoliosis, Idiopathic • Scoliosis, Degenerative • Trauma o Lateral Compression Fracture, Lumbar o Lateral Compression Fracture, Thoracic o Lateral Flexion Injury, Cervical • Scoliosis, Neuromuscular o Cerebral Palsy o Muscular Dystrophy o Friedrich Ataxia o Poliomyelitis o Hemiparesis/Hemiplegia o Paraparesis/Paraplegia • Scoliosis and Kyphosis, Congenital o Partial Vertebral Duplication o Failure of Vertebral Formation o Klippel-Feil Spectrum o VACTERLAssociation • Infection o Abscess, Paraspinal o Osteomyelitis, Pyogenic o Osteomyelitis, Granulomatous • Failed Back Surgery Syndrome • Neurogenic (Charcot) Arthropathy • Limb Length Inequality • Chest Wall Abnormality o Rib Anomaly o Sprengel Deformity Less Common • Pleural or Pulmonary o Empyema

Pneumonectomy o Fibrothorax • Tumor o Pathologic Vertebral Fracture o Osteoblastoma o Osteoid Osteoma • Congenital Syndromes with Normal Segmentation o Connective Tissue Disorders o Neurofibromatosis Type 1 o Osteogenesis Imperfecta o Mucopolysaccharidoses o Fibrous Dysplasia o Fetal Alcohol Syndrome o Proteus Syndrome o Tethered Spinal Cord • Radiation Therapy in Childhood o

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Painful scoliosis: Trauma, tumor, infection • Short-curve scoliosis: Congenital anomaly, tumor, infection, trauma, degenerative, post-operative • Balanced S-curve scoliosis: Idiopathic, connective tissue disorders • C-curve scoliosis: Neuromuscular, osteogenesis imperfecta

Abnormality

Scoliosis, Idiopathic

II 1 10

Anteroposterior radiograph shows classic, balanced, S-shaped curve, convex to right in thoracic spine. There is often minimal wedging of vertebrae on concave side of scoliosis.

Coronal T2WI MR shows asymmetric degeneraUve disc disease, with narrowing and discogenic sclerosis E!:t on left at U-4.

SCOLIOSIS

Trauma

Scoliosis, Neuromuscular (Left) Anteroposterior radiograph shows lateral compression fracture of L 7 resulting in short-curve scoliosis. (Right) Anteroposterior radiograph shows C-shaped curve SI characteristic of neuromuscular scoliosis. Failure of Fusion of the

=

posterior elements I:] is seen in the lumbar spine.

Rib Anomaly (Left) Anteroposterior radiograph shows leFt T7 7 hemivertebra IJ::]:l Fused to T72, and right T7 I hemivertebra Fused to T70. (Right) Anteroposterior radiograph shows dextroscoliosis related to the rib anomaly SI which has

caused separation

or right

4th and 5th ribs.

Osteoid Osteoma (Left) Anteroposterior radiograph shows short-curve scoliosis and pleural thickening in patient with focal pain. Because of these Findings, CT

=

scan was performed

and

showed osteoid osteoma. (Right) Anteroposterior

radiograph shows extreme scoliosis leading to shortening of trunk in osteogenesis imperfecta. Multiple

rib fractures are a/so

present.

II 1 11

KYPHOSIS

C1l

~ C>(/) , en

c

DIFFERENTIAL DIAGNOSIS

t= Ql

c: '0.

en

Osteogenesis Imperfecta Neurofibromatosis Type 1 o Achondroplasia o Mucopolysaccharidoses • Osteomyelitis, Granulomatous o o

C1l

Common • Postural Kyphosis • Idiopathic Kyphosis • Degenerative Disc Disease • Fracture o Anterior Compression Fracture, Thoracic o Anterior Compression Fracture, Lumbar o Burst Fracture, Lumbar o Hyperflexion Injury, Cervical o Chance Fracture, Thoracic o Chance Fracture, Lumbar o Hangman's C2 Fracture o Pathologic Vertebral Fracture • Multiple Myeloma • Metastases, Lytic Osseous • Metastases, Blastic Osseous • Scheuermann Disease • Failed Back Surgery Syndrome • Hardware Failure Less Common • Osteomyelitis, Pyogenic • Seronegative Spondyloarthropathy • Juvenile Idiopathic Arthritis • Post-Operative Infection • Neurogenic (Charcot) Arthropathy • Scoliosis, Neuromuscular • Paraparesis/Paraplegia • Scoliosis and Kyphosis, Congenital o Failure of Vertebral Formation o Klippel-Feil Spectrum o Vertebral Segmentation Failure • Congenital Syndromes

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Flexible Kyphosis: Postural, sometimes degenerative, failed fusion • Short-Curve Kyphosis: Infection, trauma, Charcot arthropathy and congenital fusion anomalies, degenerative (sometimes adjacent to surgical fusion) • Undulating Endplate: Scheuermann kyphosis • Cortical Break or Angular Deformity: Trauma • Destruction Vertebral Endplate: Infectious or post-infectious, neuropathic arthropathy, severe instability • Fused Vertebrae: Congenital, juvenile idiopathic arthritis, infection, seronegative spondyloarthropathy, post-traumatic, post-surgical • Multiple Wedged Vertebrae: Osteoporosis, pathologic fracture due to myeloma or metastasis, Scheuermann kyphosis, osteogenesis imperfecta, achondroplasia, mu copo Iysaccha rid osis

Degenerative

Postural Kyphosis

Disc Disease

II 1 12

Lateral radiograph shows diffuse kyphosis without bony abnormality. This is a common finding due to poor posture and may become fixed over time.

l.iJteral radiograph

shows

loss of normal

lordosis and

I:] due to degenerative disc disease. Degenerative kyphosis is

slight

kyphosis

common

at

C4-5

and

C5·6

in both cervical and lumbar spine.

KYPHOSIS

Anterior

Compression

Fracture, Thoracic

Burst Fracture, Lumbar (Left) Lateral radiograph shows multiple compression fraclUres due to senile osteoporosis in 80 year old patient. Always consider multiple myeloma in differential of this appearance. (Right) Lateral radiograph shows dynamic kyphosis at acute burst fraclure when patient stands upright in a brace 81.

=

=

Measure

deformity

from

1

level above fracture to I level below.

Chance Fracture, Lumbar

Failed Back Surgery Syndrome (Left) Sagitlal bone CT shows kyphosis due to combination of anterior compression and posterior distraction with horizontal spinous process fraclure 81 and widened interspinous distance ~. (Right) Lateral radiograph shows kyphosis al 13-4. Deformity developed post-surgery. Lucency around pedicle screw -7 is sign of failed fusion.

=

=

Achondroplasia

Osteomyelitis,

Granulomatous (Leh) Lateral radiograph shows anteriorly wedged vertebral bodies, scalloped posterior vertebral body cortices and short pedicles characteristic of achondroplasia. (RighI) Sagitlal bone CT shows

=-

characteristic hairpin-turn kyphosis called gibbus deformity and extensive spinal fusion seen in POll disease (spinal tuberculosis).

=

II 1 13

ro ~ DC/), C/)

c

co ~

IC1l

c '0.

en

KYPHOSCOLIOSIS,

DIFFERENTIAL DIAGNOSIS Common • Traumatic o Burst Thoracolumbar Fracture o Lateral Compression Fracture, Lumbar o Lateral Compression Fracture, Thoracic o Lateral Flexion Injury, Cervical o Chance Fracture, Thoracic • Congenital o Scoliosis and Kyphosis, Congenital o Failure of Vertebral Formation o Klippel-Feil Spectrum o Partial Vertebral Duplication o Tethered Spinal Cord o Caudal Regression Syndrome • Scoliosis, Idiopathic • Scheuermann Disease • Scoliosis, Neuromuscular • Juvenile Idiopathic Arthritis • Kyphosis, Idiopathic • Kyphosis ormal in Infants Less Common • Infection o Osteomyelitis, Pyogenic o Osteomyelitis, Granulomatous o Prevertebral Abscess o Post-Operative Infection • Tumor o Osteoid Osteoma o Osteoblastoma o Aneurysmal Bone Cyst o Ewing Sarcoma o Langerhans Cell Histiocytosis

• • • • •

CHILD

Syringomyelia Neurofibromatosis Type 1 Connective Tissue Disorders Post-Operative Spinal Complications Diastematomyelia

Rare but Important • Post-Radiation

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • MR may be useful in certain cases o Painful scoliosis: Tumor, infection o Atypical curve: Often have underlying bony or neural abnormalities o Congenital scoliosis: Assess full extent of bony abnormalities • CT useful to characterize congenital scoliosis Helpful Clues for Common Diagnoses • Congenital curve may progress rapidly, especially if it includes unfused hemivertebrae • Scheuermann kyphosis presents in adolescence, may be misdiagnosed as fracture o Involves multiple levels, see Schmorl nodes or undulation of end plates without angular deformity • Lumbar kyphosis normal in infants o Lumbar lordosis develops after infant begins to sit upright

Traumatic

II 1 14

Sagillal bone CT shows kyphoUc deformity !l:lI in flexion-distraction type injury. Kyphosis also seen due to burst or compression fracture.

Anteroposterior bone CT 3D reformation shows left T II hemivertebra Short-curve, unbalanced kyphoscoliosis is typical of congenital kyphoscoliosis.

=.

KYPHOSCOLIOSIS,

CHILD

Scheuermann

Disease (Left) COlOnaIbone CT shows Klippe/-Feil spectrum, with extensive fusion anomalies of cervical spine, with dexlroscoliosis. Kyphosis was also present. (Right) Sagittal bone CT shows kyphosis due to vertebral wedging~. Note undulating endplates and Schmor/ nodes at 4 contiguous levels. 7S% of Scheuermann cases show

scoliosis.

Juvenile Idiopathic

Arthritis (Left) Anteroposterior radiograph shows C-shaped scoliosis typical of

neuromuscular scoliosis. There is a/so often

persistence of infantile kyphosis in neuromuscular disease. (Right) Lateral radiograph shows mild kyphosis due to cervical fusions~. Kyphosis due to juvenile chronic (idiopathic) arthritis is usually not severe.

Infection (Left) Sagittal T2WI MR shows infantile

tuberculosis

causing kyphotic deformity, epidural abscess =:I, and pre vertebral abscess ~. Spinal TB can be present without pulmonary abnormalities. (Right) Lateral radiograph shows large expansile mass =:I, aneurysmal bone cyst in this case, involving posterior

elements and causing kyphotic deformity at C2- J level.

II 1 15

PlATYSPONDYlY,

Cll

DIFFUSE

~

CL (/J

U, C Cll ~

IQl C

a. (/)

DIFFERENTIAL DIAGNOSIS Common

• • • •

Multiple Myeloma Osteoporosis Sickle Cell Scheuermann Disease

less Common

• Metastases, Lytic Osseous • Osteogenesis Imperfecta • Mucopolysaccharidoses Rare but Important

• • • • • •

Spondyloepiphyseal Dysplasia Ehlers-Danlos Syndrome Achondroplasia Cushing Disease Thanatophoric Dwarfism Gaucher Disease

ESSENTIAL INFORMATION Key Differential

Diagnosis Issues

• Uncommon condition irrespective of cause • In adults, usually due to severe osteoporosis or myeloma o Compression fractures may be so extensive that they cause uniform flattening at all levels o More commonly, amount of vertebral height loss varies from level to level o Metastases uncommonly show uniform platyspondyly • Dwarfisms show limb abnormalities also

Multiple Myeloma

II 1 16

Lateral radiograph shows 1055 of vertebral body height at almost all visualized levels, due to multiple pathologic fractures. Height los5 is greater anteriorly than posteriorly.

• Connective tissue disorders show scalloping of posterior vertebral body margin o Due to dural ectasia Alternative

Differential

Approaches

• Uniform flattening o Spondyloepiphyseal dysplasia o Osteogenesis imperfecta • Anterior height loss> posterior o Osteoporosis o Multiple myeloma o Scheuermann disease o Metastases, lytic osseous o Osteogenesis imperfecta • Vertebral "beak" o Mucopolysaccharidoses o Achondroplasia (at thoracolumbar junction) • Limited to lumbar region o Ehlers-Danlos syndrome • Central loss of vertebral body height o Sickle cell ("Lincoln Log" vertebrae) o Cushing disease ("fish mouth" vertebrae) o Osteogenesis imperfecta ("fish mouth" vertebrae) o Gaucher disease • Also seen in multiple rare dwarfism syndromes o Enchondromatosis has been reported to involve spine (spond yloenchondrod ysplasia) o Dysosteosclerosis o Kniest dysplasia

Sickle Cell

Sagittal T1WI MR shows abnormal low T1 marrow signal and characteristic 1055 of vertebral body height at all levels due to bone infarcts.

PLATYSPONDYLY,

Scheuermann

Disease

DIFFUSE

Osteogenesis

Imperfecta (Left) Laleral radiograph shows flattened vertebral bodies and undulating endplates at every visualized level. Vertebral

flattening

;5

characteristically more severe anteriorly than posteriorly. (Right) Anteroposterior radiograph shows flattening of all included vertebral bodies, central endplate depression,

and severe osteoporosis.

Achondroplasia fLeft) Sagittal T2WI MR shows lIattened vertebral bodies throughout visualized spine and undulating endplates. Appearance differs from Scheuermann disease in lack of vertebral wedging (Righi) Sagittal TI WI MR shows diffuse vertebraillattening. At thoracolumbar junction there is additional,

characteristic

anterior hypoplasia in kyphosis.

Thanatophoric

Dwarfism

Gaucher

resulting

Disease (Left) Anteroposterior radiograph

shows diffuse

=

platyspondyly and characteristic limb shortening and deformity~. (Right) Lateral radiograph shows extensive bony infarcts and" Lincoln Log" appearance ~ that can mimic sickle celf disease.

=

II 1 17

SACRAL MASS, ADULT

CIl

.~ 0(fJ

,

Vi C

~ CI>

c Q.

III

Common • Lytic Osseous Metastases • Sacral Stress Fracture • Occult Intrasacral Meningocele • Chordoma • Lymphoma • Giant Cell Tumor • Multiple Myeloma • Paget Disease

•

Less Common • Anterior Sacral Meningocele • Aneurysmal Bone Cyst • Chondrosarcoma Rare but Important • Secondary Osteosarcoma • Ewing Sarcoma

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Multiplicity suggests metastases or multiple myeloma • Soft tissue component with character of internal matrix (e.g., chondroid matrix) can provide diagnostic clues

II 1 18

Helpful Clues for Common Diagnoses • Lytic Osseous Metastases o Most often with breast, lung, kidney, thyroid, oro- & nasopharyngeal, GI tract, bladder, uterine, ovarian, melanoma, chordoma, & paraganglioma primaries • ExpansiJe, osteolytic lesions observed with kidney & thyroid mets o Hypointense on Tl WI, hyperintense on T2WI & STIR; diffusely enhance • T1 hypointensity after therapy may be residual tumor or fibrosis o Cortex, particularly posteriorly, & pedicles are often destroyed, while intra vertebral discs are usually spared • Sacral Stress Fracture o T1 hypointensity & T2 hyperintensity reflects marrow edema • Occult Intrasacral Meningocele o CSF pulsation remodels sacral canal, which shows smooth enlargement o Follows CSF signal intensity; no neural elements are seen within cyst

Tarlov cyst is similar in etiology: Congenital dilatation of nerve root meningeal sleeve • Tarlov cysts frequently multiple & eccentrically centered over neural foramen Chordoma o Arise in midline o Most common locations: Sacrococcygeal> spheno-occipital> vertebral body o Hyperintense to discs on T2WI; internal septations, variable enhancement, often amorphous intra tumoral calcium o Can have large soft tissue component o Involvement of adjacent vertebral bodies via transdiscal extension; may be epidural, perivertebral, & perineural extension Lymphoma o May involve epidural space with vertebral body extension & bone erosion o May be primarily osseous with bone destruction or "ivory vertebra" appearance o Appears slightly hyperdense on NECT & demonstrates homogeneous enhancement Giant Cell Tumor o Lytic expansile lesion in sacrum or a vertebral body with narrow zone of transition & usually non-sclerotic margins o Although internal matrix is absent, there may be residual bone trabeculae o Can coexist with an ABC o Radiologically & histologically identical to brown tumors, which occur in setting of hyperparathyroidism o Majority occur in 3rd to 5th decades Multiple Myeloma o Bone scintigraphy detects only 10%; PET imaging is sensitive for monitoring treatment response, as MM lesions are metabolically active o Clinically, monoclonal gammopathy and Bence Jones proteinuria are present Paget Disease o Hypointense cortex & thickened trabeculae o Active phase: Fibrovascular marrow (Tl hypointense/T2 hyperintense) o Mixed phase: Fatty marrow (hyperintense on T1 WI and T2WI) o

DIFFERENTIAL DIAGNOSIS

CIl

•

•

•

Helpful Clues for Less Common • Anterior Sacral Meningocele

Diagnoses

SACRAL MASS, ADULT Presacral cyst that is contiguous with thecal sac, protruding through an anterior osseous defect; widened sacral canal & neural foramina o No soft tissue mass, enhancement, or calcification, which are seen with sacrococcygeal teratomas o Neurenteric cyst is within spinal canal; may be associated with dysraphism & vertebral formation anomalies • Aneurysmal Bone Cyst o Arise in neural arch & majority (75-90%) extend into vertebral body o Cortical thinning & focal cortical destruction are common • More permeative bone destruction, wider zone of transition and infiltration into surrounding soft tissues with sarcomas • Expansile remodeling of bone can result is loss of pedicle contour on AP radiograph o Fluid-fluid levels can be seen with telangiectatic osteogenic sarcoma as well as o

ABC

Majority of patients younger than 20 years o Renal cell carcinoma can also have a "soap bubble" expansile appearance • Chondrosarcoma o May be isolated or secondary to osteochond rom a/ en ch on drom a degeneration o 50% of these lytic destructive lesions demonstrate a chondroid matrix with "rings and arcs" o

o

Cortical disruption tissues

& extension

into soft

Helpful Clues for Rare Diagnoses • Secondary Osteosarcoma o Often has an osteolytic, expansile appearance without periosteal reaction • Cortical disruption may not be present • Permeative appearance with a wide zone of transition • 80% have a bone matrix and 20% have a lytic appearance o Secondary osteosarcomas can occur after radiation treatment or may be sarcomatous transformation of Paget disease or other benign bone lesion • Most secondary osteosarcomas patients are older than 50 years • Insidious onset of pain, greatest at night o Calcified pulmonary metastases can be seen • Ewing Sarcoma o Permeative destructive lesions of sacrum or vertebral body; cortical perforations rather than extensive cortical bone loss o Majority before 20 years old; however, second smaller peak at age 50 years, which present with spine & sacral lesions o Central areas of necrosis are common

lytic Osseous Metastases

Axial NEeT shows multiple blas/ic BI and somewhat permeative lytic lesions throughout the sacrum and visualized pelvi.t;. There is no SOfllissue mass.

=

Axial T1 WI M R shows an il/-defined T1 hypoinlense area involving the right sacral ala ~ with haziness of the adjacent fat & obscuration of cortical margins. Discrete fracture line is not identified.

II 1 19

SACRAL MASS, ADULT

co

~ Cl. (fJ, (/)

c

co ~

IQ)

c Cl.

(fJ

Occult Inlrasacral Meningocele (Left) Axial T2WI MR demonstrates an extradural cyst IJ:ll of fluid signal in caudal spinal canal. Cyst remodels and enlarges the spinal canal. (Right) Sagittal TI C+ MR shows a flonenhancing extradural cyst in caudal spinal canal. These are sacral meningeal cysts, while dorsal meningoceles arc true meningoceles protruding through dysraphism.

=

(Left) Sagittal TI WI MR shows a destructive sacral mass that demonstrates T I hypointensily. Mass may

=

extend along nerve roots and enlarge neural foramina. (Right) Sagittal T2WI MR shows a destructive sacral mass with marked T2 hyperintensityand septalioflS, which is characteristic of a chordoma.

=

Locaf recurrence

is common

(90%), and there may be seeding along the operative

tract

(Left) Axial NECT shows epidural lymphoma that fills the left sacral neural foramina ~ and erodes into adjacent bone 1J:ll. (Right) Sagittal NECT shows massive sacral giant cell tumor with pelvic extension~. There is erosion of the inFerior sacrum Pathologic fractures occur in 30%, and these lesions are locally aggressive with 12·50% recurrence.

=.

II 1 20

Occult Intrasacral Meningocele

SACRAL MASS, ADULT

(Left) Axial T2WI MR shows innumerable small marrow

lesions

= in sacrum and

iliac wings. (Right) Axial T1WI MR shows typical heterogeneous fatty signal and thickened dark trabeculae of Paget disease involving the sacrum.

=

Anterior

Sacral Meningocele

Secondary Osteosarcoma (Left) Sagittal T1 WI MR

reveals a cystic presacral

=.

mass Sacrum has a scimitar shape. There is a

sma/J unrelated Tarlav cyst 81. (Right) Axial NEeT with sofe tissue windows confirms an aggressive, expansile process & with multiple areas of cortical breakthrough. No definite bone production by tumor is

present.

Ewing Sarcoma

Ewing Sarcoma (Left) Axial bone CT shows i/f·defincd sclerosis in right parasacral ilium with

a

unilaminar periosteal reaction. Sofllissue mass ~ is appredable on both sides of ilium. (Right) Coronal STIR MR demonstrates heterogeneous high signal on STIR and involvement of right sacrum ~ and adjacent portions of right ilium. It extends along sacral

nerves a a common pattern in sacral Ewing sarcoma.

II 1 21

SACROCOCCYGEAL

ro

~ Q. CfJ, rJl C

ro

.=

Ql

c Q.

CIl

DIFFERENTIAL DIAGNOSIS Common • Sacrococcygeal Teratoma • Presacral Abscess Less Common • Chordoma • Neuroblastic Tumor • Plexiform Neurofibroma • Lymphoma • Chondrosarcoma • Ewing Sarcoma Rare but Important • Rhabdomyosarcoma • Osteosarcoma • Dermoid and Epidermoid Tumors • Myxopapillary Ependymoma • Anterior Sacral Meningocele • Terminal Myelocystocele • Enteric Cyst

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Myriad pathologies produce sacrococcygeal masses; clinical data directs differential list • Fever, elevated inflammatory markers prompt search for infection source • Identification of tumor matrix narrows differential considerations • Location and relationship of mass to important regional structures impacts tumor resecta bility • Look for osseous invasion or epidural extension, which may alter surgical planning

II 1 22

Helpful Clues for Common Diagnoses • Sacrococcygeal Teratoma o Very heterogeneous density/signal intensity, enhancement of solid tumor portions o AAP grade based on proportion of external and internal tumor • Male sex, large proportion internal tumor, older age at diagnosis portend worse outcome o Often detected on routine obstetrical ultrasound => elective cesarean section • Fetal MR valuable for confirmation of diagnosis, AAP grading

MASS, PEDIATRIC Sacrum and coccyx usually spared, even when tumor spreads into spinal canal via sacral hiatus o Coccyx must be resected or recurrence risk high • Presacral Abscess o Fever, serum inflammatory markers usually elevated, prompting clinical consideration of diagnosis o Regional soft tissue inflammation, discitis, epidural abscess, or vertebral osteomyelitis o Rim enhancement and diffusion restriction on DWI MR characteristic o

Helpful Clues for Less Common Diagnoses • Chordoma o Strong predilection for sacrum (50%) • Other common locations include clivus (35%) and vertebra (15%) o Characteristic very high T2 signal intensity limits differential considerations o No tumor matrix (in distinction to chondrosarcoma) • Osseous debris within tumor may mimic matrix on CT • Neuroblastic Tumor o Paraspinal location along sympathetic chain (neural crest derivatives) o Benign (ganglioneuroma) -+ intermediate grade (gangJioneuroblastoma) highly malignant (neuroblastoma) o Frequently calcified, encircles vessels and regional structures o Important upstaging findings affecting surgical management include bilaterality and epidural extension • MR best imaging modality for detecting tumor extension into spinal canal through neural foramen • Plexiform Neurofibroma o Neurofibromatosis type 1 o Grape-like or botryform morphology with characteristic distribution along nerves (major or minor peripheral nerves/plexi) o Hyperintense on STIR MR, T2Wl MR • Lymphoma o Protean imaging appearances o Often large at diagnosis; may be focal or diffuse o Relatively low signal intensity on T2WI MR ± mild diffusion restriction reflects high tumor cellularity -+

SACROCOCCYGEAL MASS, PEDIATRIC • Chondrosarcoma a Very high T2 signal intensity; may be difficult to distinguish from chordoma on imaging a Chondroid matrix (when present, 50%) diagnostic • Ewing Sarcoma a Usually older child/adolescent presentation age a Aggressive or permeative bone destruction a Cellular signal intensity (relatively low signal intensity on T2WI MR) Helpful Clues for Rare Diagnoses • Rhabdomyosarcoma a Aggressive soft tissue mass with frequent bone invasion a Rarely arises primarily in sacrum; usually regional extension from prostate or uterus primary tumor a Signal characteristics variable; frequently shows cellular characteristics with lower signal intensity on T2WI MR • Osteosarcoma a Destructive lesion with frank bone destruction and large soft tissue mass a May arise in pre-existing lesion (aneurysmal bone cyst, fibrous dysplasia) a Osteoid matrix makes diagnosis • Dermoid and Epidermoid Tumors a Consider previous lumbar puncture with nonstyletted needle, congenital dermal sinus tract a Contains fat &/or squamous debris

Sacrococcygeal Teratoma

Epidermoid component ~ diffusion restriction Myxopapillary Ependymoma a Very uncommon sacral and presacral ependymomas have been described a Most myxopapillary ependymomas arise near conus or filum (may be confined entirely to filum terminale) a CSF-disseminated intradural metastases common Anterior Sacral Meningocele a Cyst contiguity with thecal sac through enlarged neural foramen is diagnostic a Most ASM are simple CSF signal cysts; may also have lipomatous component (complex ASM) Terminal Myelocystocele a Spinal cord termination always low a Cystic dilatation of distal spinal cord central canal (myelocystocele) extending through a dilated subarachnoid fluid collection (meningocele) Enteric Cyst a Fortuitous adjacent location to sacrum in isolated mesenteric or intestinal duplication cyst a Split notochord malformations (neurenteric cysts) a

•

•

•

•

Other Essential Information • Patient age and signal characteristics on MR imaging are most helpful criteria to narrow pertinent differential diagnosis list

Presacral Abscess

Sagittal T2WI MR shows typical case of large MP type 2 SeT with mixed cystic and solid mass. The internal

Sagillal STIR MR shows intervertebral disc space infection at L5~57 level with extensive prevertebral T2

portion is predominately solid portion E1 is more cystic.

hyperinlensily representing presacral abscess.

=

and the external

II 1 23

SACROCOCCYGEAL

co

MASS, PEDIATRIC

~ 0.. CIJ, Cf)

c co

t=

Chordoma

Q)

c 'Q. CJ)

(Left) Sagittal STIR MR shows a well-defined, markedly hyperintense mass at the S2 level involving the central aspect o( the sacrum extending into presacral space and dorsally into sacral canal. (Right) Sagittal T2WI MR demonstrates a large presacral soft tissue mass with sacral vertebral bone involvement as well as epidural extension ~ through the neural foramina.

=

Plexiform

Neurofibroma

lymphoma

(Left) Coronal STIR MR in a patient with NF / reveals multilevel bilateral T2 hyperintense plexiform neurofibromas involving the spinal and pelvic nerves and relevant plexuses. (RighI) Axial TI C+ MR shows a large destructive sacral mass with avid enhancement spreading into the dorsal soft

rs

tissues.

Ewing Sarcoma (Left) Axial T2WI FS MR shows a large sacral Ewing sarcoma with bone destruction and extension into the dorsa/lumbosacral soft tissues. (Right) Sagittal T2WI MR demonstrates a large exophytic sacral mass engulfing lower sacral verlebra and extending into central spinal canal It] through the sacral hiatus EB

II 1 24

Rhabdomyosarcoma

SACROCOCCYGEAL

MASS, PEDIATRIC

(J)

"0

::::l

11l

-l

~ tll ::::l

en,

Osteosarcoma (Left) Axial T1 C+ FS MR demonstrates a destructive pelvic mass with multiple enhancing areas of solid tumor ~ as well as fluid-filled, nonenhancing necrotic regions =:I. (Right) Sagittal T1 WI MR depicts a mixed signal intensity

(j) -0

~ tll

expansile extradural sacral mass =:I. Additional findings include low-lying spinal cord and fatty filum infiltration.

Myxopapillary

Ependymoma

Anterior

Sacral Meningocele

rs MR

(Left) Sagittal T1 C+ reveals a heterogeneous

presacral mass with osseous destruction and spinal extension. Conus ;5 low lying. Exact pathological diagnosis of this rare lesion has been debated but shows many features of sacral ependymoma. (Right) Sagittal T2WI MR demonstrates a large CSF signal intensity presacral cyst that is contiguous with the thecal sac through an enlarged sacral foramen =:I.

Anterior

Sacral Meningocele

Terminal Myelocystocele (Left) Sagittal T1WI MR in a patient with caudal regression depicts a variant complex ASM with both cyst and lipoma components extending through the sacral foramina to produce sacral mass. (Right) Sagittal T1WI MR shows classic

=

appearance

of terminal

myelocystocele, with a low-lying tethered spinal cord, distal hydromyelia =:I traversing a meningocele EJ.

II 1 25

SACRAL DEFORMITY

ro

~

n.

(f)

enc

ro ~

t-

a>

c

'Q.

en

Common • Sacral Foraminal Mass o Dural Dysplasia o Neurofibroma • Insufficiency Fracture, Sacral • Sacral Traumatic Fracture • Metastatic Disease • Ependymoma, Myxopapillary,

•

Spinal Cord

less Common • Dorsal Dysraphism o Myelomeningocele/Myelocele o Lipomyelomeningocele/Lipomyelocele o Terminal Myelocystocele • Meningocele, Occult Intra sacral • Meningocele, Anterior Sacral • Chordoma • Teratoma, Sacrococcygeal • Caudal Regression Syndrome

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Bone-algorithm CT and MR are complementary modalities • CT superior to assess bone cortex o Bony remodeling: Dural dysplasia, neurofibroma, ependymoma o Bone destruction: Metastases, chordoma • MR superior to assess soft tissue contents of the sacral canal and foramina Helpful Clues for Common Diagnoses • Dural Dysplasia o Intrinsic weakness in dura o Transmission of chronic CSF pressures leads to bony remodeling and expansion of lumbosacral canal and neuroforamina o Contents follow CSF signal on MR and show no appreciable enhancement o Can be seen with neurofibromatosis type 1, Marfan disease, homocystinuria, Ehlers-Danlos, and ankylosing spondylitis • Neurofibroma o Fusiform enlargement of nerve root(s) o Heterogeneous enhancement o Multiple lesions typical of type 1 neurofibromatosis

II 1 26

Bony remodeling caused by intraspinal or transforaminallesions can cause scalloping or the posterior lumbar vertebra and sacrum, neuroforaminal widening Insufficiency Fracture, Sacral o Unilateral or bilateral vertical component through the sacral alae, possibly with a horizontal component through the body o Subtle fracture may be hard to identify even with high-quality CT o Associated marrow edema signal most conspicuous on fat-saturated T2WI (e.g., STIR) o Increased tracer uptake on bone scan Sacral Traumatic Fracture 095% occur in conjunction with other pelvic fractures o Denis classification • Zone 1: Lateral to neuroforamina • Zone 2: Through neuroforamina • Zone 3: Through spinal canal o Higher Denis zones associated with increasing probability of significant neurologic deficit Metastatic Disease o Renal, lung, breast, and prostate carcinomas are common primaries to develop osseous metastases o Sacral fracture can develop within bone weakened by tumor or by pelvic radiation therapy Ependymoma, Myxopapillary, Spinal Cord o Most common neoplasm of the conus and distal spinal canal o Marked enhancement typical o Can show signs of necrosis (heterogeneity, cyst formation) and hemorrhage: Subarachnoid hemorrhage, superficial siderosis o Bony remodeling when large: Scalloping of the margins of the spinal canal, foraminal enlargement o

DIFFERENTIAL DIAGNOSIS

•

•

Helpful Clues for less Common Diagnoses • Dorsal Dysraphism o Common features: Everted elements of dorsal neural arch; tethered, dysraphic cord o LipomyelomeningoceJe, lipomyelocele: Placode adherent to fatty mass contiguous with subcutaneous fat; intact skin

SACRAL DEFORMITY

Myelomeningocele, myelocele: Placode exposed; no overlying skin o Lipomyelocele, myelocele: Placode lies within spinal canal o Lipomyelomeningocele, myelomeningocele: Placode and meninges protrude through spinal defect o Terminal myelocystocele: Meningeal sac containing tethered, hydromyelic cord extends through sacral defect; intact skin • Meningocele, Occult Intrasacral o CSF-containing meningeal cyst within the sacral canal; thin or imperceptible wall; no appreciable enhancement o Does not contain neural elements o Chronic CSFpulsation pressure leads to expansion and bony remodeling o Often asymptomatic, may be associated with low back pain, radicular symptoms, and bladder dysfunction • Meningocele, Anterior Sacral o CSF-containing meningeal sac protruding into the pelvis through an enlarged sacral foramen or a defect in a dysplastic sacrum o Important to determine if nerve roots traverse the neck of the sac for surgical planning • Chordoma o Malignant tumor arising from notochord remnants; 50% sacrococcygeal in location o Hyperintense on T2WI; usually containing multiple septae; calcification common in sacral chordoma o

Peak incidence in 5th and 6th decades, rare in children • Teratoma, Sacrococcygeal o Rare, congenital tumors arising from totipotential cells in the caudal cell mass o Most are large, encapsulated with mixed solid and cystic components o Sacral canal involved in 2% o Classified by location • Type I: Caudal, external tumor mass without a significant presacral component • Type II: Caudal tumor with significant pelvic component • Type III: Mainly intrapelvic, with minimal external mass • Type IV: Completely intrapelvic (presacral) • Caudal Regression Syndrome o Spectrum of congenital anomalies arising from maldevelopment of lower vertebral column, cord, and pelvic viscera o Hypoplastic distal cord with truncated or "blunted" terminus o Hypoplasia or variable agenesis of the lumbosacral spine o Non-spine anomalies, variably present • Anal atresia • Bladder exstrophy, abnormalities of external genitalia • Renal aplasia or ectopia o

Dural Dysplasia

Axial

NEeT

and foramina

shows widened, remodeled sacral canal

1m due

to enlarged thecal sac and nerve

root sleeves in this patient with dural dysplasia.

=

Sagittal T2WI MR shows marked seal/oping of the posterior sacrum and L5 vertebral body

with an

II 1

enlarged thecal sac in this patient with dural dysplasia and neurofibromatosis

type

,.

27

SACRAL DEFORMITY

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ro

D-

,

C/) (/)

<::

C1l

t= Ql

<:: Q.

en

Neurofibroma

Insufficiency

Fracture, Sacral

(Left) Axial NECT shows enlarged sacral foramina ~ due 10 multiple neurofibromas

in this patient

with NF I. Note large left gluteal mass due 10 a plexiform

neurofibroma

B.

(Right) Axial NEeT shows marked osteoporosis and disruption of the anterior sacral cortices due to bilaleral insufficiency fraclures ~.

Sacral Traumatic Fracture

Metastatic Disease

Ependymoma, Myxopapillary, Spinal Cord

Myelomen ingocele/ Myelocele

(Left) Axial bone CT shows fraClure through the left sacral foramina (zone It) Et and subtle fraclure of the right sacral ala ~. (Right) Axial T2WI FS MR shows

presacral rhabdomyosarcoma engulfing and invading the

sacrum~

(Left) Sagi!!al T1 C+ MR shows large, lobulated hyperintense mass filling the distal thecal sac and expanding/remodeling the sacrum C>. (Right) Sagittal T2Wf MR shows open spinal dysraphism and a CSF-filled, hyperintense myelomeningocele sac containing

nerve roots

inserting onto a dorsal neural placode~.

II 1 28

SACRAL DEFORMITY

(Left) Sagittal TI WI MR shows low-lying spinal cord inserting directly into a

lumbosacral lipomatous

a

mass extending through a dorsal sacral defect to be contiguous

with

subcutaneous

fat. Note distal

=.

hydrosyringomyelia (Right) Sagittal STIR MR shows asymptomatic large CSF-signal cystic mass within the sacral canal associated with marked thinning/remodeling of the sacral body.

=-

Meningocele,

Anterior

Sacral

Chordoma (Left) Sagittal T2WI MR shows presacral cyst 81 contiguous with thecal sac through an enlarged sacral foramen ~. (Right) Sagittal T2WI MR shows large, expansile, well-defined mass involving sacrococcygeal region with heterogeneously hyperintense

and fine

internal septations

Teratoma,

=.

Sacrococcygeal (Left) Sagittal T2WI MR shows a large, cauda! mass containing soft tissue elemen15 and septated cys15 81. Foci of hypointense signal correspond to

=

calci{;cation

or hemorrhage

(Right) Anteroposterior radiograph shows hypoplastic sacrum 81 and iliac wings in this patient

with severe caudal regression syndrome. L4 and LS vertebrae are absent

=.

II 1 29

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ro

t= Gl

c: a.

I/)

ACUTE BACK PAIN/RADICUlOPATHY, POST-OPERATIVE

DIFFERENTIAL DIAGNOSIS Common • Intervertebral Disc Herniation, Recurrent • Intervertebral Disc Herniation, Acute o Intervertebral Disc Herniation, Cervical o Intervertebral Disc Herniation, Thoracic o Intervertebral Disc Herniation, Lumbar o Intervertebral Disc Extrusion, Foraminal • Peridural Fibrosis less Common • Post-Operative Infection o Abscess, Paraspinal o Abscess, Epidural o Abscess, Subdural • Post-Operative Complication o Hematoma • Hematoma, Epidural • Hematoma, Subdural o Hardware Failure o Vertebroplasty Complications o Bone Graft Complications Rare but Important • Post-Operative Complication o Brachial Plexus Traction Injury o Infarction, Spinal Cord • Post-Operative Infection o Abscess/Myelitis, Spinal Cord

ESSENTIAL INFORMATION

II 1 30

Helpful Clues for Common Diagnoses • Intervertebral Disc Herniation, Recurrent o Focal extension of disc material beyond endplate margins at previously operated intervertebral disc level o Subset of failed back surgery syndrome (FBSS) o Fat suppression of Tl WI (pre- and post-gadolinium) may increase sensitivity for detecting peridural fibrosis and for differentiating fibrosis from disc herniation • Intervertebral Disc Herniation, Acute a Localized « 50% of disc circumference) displacement of disc material beyond edges of vertebral ring apophyses a Unfortunate luck to present with new disc herniation after previous surgery at another level • Peridural Fibrosis

a

a a

Scar formation within epidural space following lumbar surgery Subset of FBSS Fat suppression of Tl WI (pre- and post-gadolinium) increases sensitivity for detecting peridural fibrosis and for differentiating fibrosis from disc herniation

Helpful Clues for less Common Diagnoses • Post-Operative Infection a Infectious sequelae following operative procedures a May manifest in one or more areas at operative site including paravertebral tissues and subdural or epidural spaces, but frequently starts in intervertebral disc space a Abscess, Paraspinal • Infection of paravertebral soft tissues surrounding spine • Paravertebral enhancing phlegmon or peripherally enhancing liquified collection a Abscess, Epidural • Extradural spinal infection producing abscess formation • Frequently spondylodiscitis extends into adjacent epidural space => enhancing epidural phlegmon ± peripherally enhancing fluid collection • May also see isolated epidural abscess without discitis • Lower thoracic, lumbar> cervical, upper thoracic a Abscess, Subdural • Purulent pus collection developing in "potential" space between dura and arachnoid • Post-Operative Complication a Hematoma, Epidural • Blood extravasation into the epidural spinal compartment • Long segmental extra-axial mass encasing or displacing spinal cord or cauda equina • Typically multisegmental, but Illay be focal when associated with focal fracture or disc extrusion o Hematonla, Subdural • Accumulation of blood between dura and arachnoid

ACUTE BACKPAIN/RADICULOPATHY, POST-OPERATIVE

o

o

o

• Signal characteristics variable depending on age of blood products Hardware Failure • Mechanical breakdown, malfunction, or malposition of metallic implant • May present either with chronic pain or calamitously with acute pain Vertebroplasty Complications • Cement extravasation into spinal canal, foramen, or vertebral venous plexus • Pulmonary artery cement embolization • Vertebral osteomyelitis • "Bounce back" vertebral fracture Bone Graft Complications • Graft migration, graft displacement, or graft extrusion • Abnormal alignment, position, or placement of graft ± associated neurologic deficit, instability, infection • Cervical> thoracic> lumbar

Helpful Clues for Rare Diagnoses • Post-Operative Complication o Brachial Plexus Traction Injury • Stretch injury or avulsion of ~ 1 cervical roots, brachial plexus • Stretch injury: Enlargement or attenuation of stretched (but contiguous) plexus elements

Intervertebral Disc Herniation, Recurrent

• Avulsion injury: Attenuated or disrupted proximal roots/rami within or immediately distal to lateral CSF-containing dural sac diverticulum devoid of neural elements ± retracted distal nerve roots, nerve "retraction ball" o Infarction, Spinal Cord • Thoracic spinal cord infarction 2° arterial occlusion (radicular artery) • Artery of Adamkiewicz frequently implicated • Usually extends to involve more than one vertebral body segment • Central hyperintensity on T2WI more common than wedge-shaped involvement of anterior 2/3 of spinal cord • Post-Operative Infection o Abscess/Myelitis, Spinal Cord • Spinal cord infection with necrosis • Spinal cord neoplasm mimic; ring-enhancing mass within cord with appropriate clinical history of inflammation/infection is highly suggestive • Pyogenic infection most common but granulomatous infections have been described • May show positive diffusion (reduced ADC) restriction similar to brain abscess, but lack of diffusion restriction does not exclude abscess

Intervertebral Disc Herniation, Recurrent

II Sagittal T1 C+ MR in a posl-operalive

=

recurrel1l

back pain demonstrates

that ventrally

compresses

a

paUent with

recurrent

the thecal sac.

L4-5 IINP

Axial Tl C+ FS MR in a post-operative

recurrent back pain reveals a large recurrent disc herniation ~~L

patient

with

post-operalive

1 31

ACUTE BACK PAIN/RADICULOPATHY,

Cll

POST-OPERATIVE

~ a. (/) , en c

~ Cll

fell

c a.

(/)

Intervertebral

Disc Herniation,

Cervical

Intervertebral

Disc Herniation,

Intervertebral

Disc Herniation,

Lumbar

Intervertebral

Disc Extrusion, Foraminal

Thoracic

(Left) Axial T2* eRE MR reveals a large left cervical disc herniation

producing

spinal cord deformation

and

narrowing of the lefllateral spinal canal. (RighI) Axial T2WI MR depic15 a left paracentral thoracic disc herniation that produces mild spinal cord deformation but no significanl narrowing of the central spinal canal.

(Lefl) Axial T2WI MR in a patient with left leg pain demonstrates a huge left lateral recess disc extrusion =:I that obliterates lhe left lateral recess and deforms the thecal sac. (RighI) Axial T2WI MR reveals a huge right Foraminal and far lateral

=

disc extrusion in a symptomatic patient with acute right leg pain.

Peridural Fibrosis (Lefl) Axial T1 C+ MR shows diffuse enhancement of right lateral epidural space and surrounding exWng root t;econdary to peridural fibrosis. There is extensive enhancement of the disc curette site =:I. (RighI) Axial T1 C+ MR depic15 extensive enhancing epidural fibrosis circumferentially

surrounding

the thecal sac =:I. Note mewl susceptibility artifact from fusion cage ~.

II 1 32

Peridural Fibrosis

ACUTE BACK PAIN/RADICUlOPATHY,

Abscess, Paraspinal

POST-OPERATIVE

Abscess, Paraspinal (LeFt) Sagiltal STIR MR aFter L4-S posterior lumbar interbody fusion (PUF) shows abnormal fluid signal intensity in L4-5 disc

interspace and posterior

50ft

tissue abscess with fluid-debris level ffi (Right) Axial T2WI MR following L4-S PUF shows increased signal intensity in dorsal soft tissues &, abscess collection surrounding posterior spinal fusion hardware (metallic susceptibility E!lI! & edema

in paraspinal muscles.

Abscess, Epidural

Abscess, Epidural (Left) Sagi!!al T7 C+ MR in a patient with back pain and fever demonstrates a well-delineated,

post-operative

rim-enhancing,

post-operative epidural abscess at the SI level (Right) Axial T7 C+ FS MR delineates a well-circumscribed,

=.

=

rim-enhancing

epidural

abscess producing mass effect and displacement of the thecal sac to the right

(LeFt) Sagi!!al T2WI MR shows two level fusion from

CJ to C5 with metal artifact from screws. Screw artifact at C5 level extends to the ventral epidural space adjacent to the spinal cord

E1.

Note congenital

fusion at

C6-7. (Right) Axial T7 C+ MR following interbody Fusion and posterior pedicle screw fixation shows

extensive enhancement

of

paraspina/ musculature involving dorsal muscles as we/J as psoas and multifidus muscles=.

II 1 33

ACUTE BACK PAIN/RADICULOPATHY,

co

POST-OPERATIVE

~ Q. (f) , (/)

c

co ~

IQ)

C

e-

rn

Hematoma,

Epidural

Hematoma,

Epidural

Hematoma,

Subdural

Hematoma,

Subdural

(Left) Sagillal T7 WI MR shows wide cervical laminectomy defect with intermediate signal intensity filling the laminectomy defect, representing epidural hematoma; which compresses posterior thecal sac and spinal cord~. Note surgical drain 81. (Right) Sagittal TlWI MR following L]-L5 laminectomy shows intermediate signal mass (not /racking CSF) filling the laminectomy site and extending into dorsal epidural space, compressing

=

the thecal sac.

(Left) Sagillal T7 WI MR reveals a mildly hyperintense subacute subdural hematoma I:ll following spinal surgery that dorsally

compresses the thecal sac and spinal cord. (Right) Sagittal T2WI MR following vertebroplasty in a patient with severe multilevel

degenerative disc disease shows severe compression deformities at T72, L1, and moderate deformity at L2. Note subdural I:ll and subarachnoid blood layer PJ::l in distal thecal sac.

Hardware (Left) Axial bone CT following myelography with bilateral pedicle screws in place shows lucency surrounding the left pedicle screw indicating loosening

with superimposed stress fracture through the left pedicle and posterior vertebral body I:ll. (Right) Lateral radiograph in an NF I patient with operated

scoliosis shows dramatic presentation with acute back pain and spinal hardware protruding through skin.

II 1 34

Failure

ACUTE BACK PAIN/RADICULOPATHY,

POST-OPERATIVE

Bone Graft Complications (Lefl) Axial TI WI MR shows injected low signal intensity methacrylate within the anterior vertebral body as intended, as well as extending into the left

paravertebral soft tissues adjacent 10 the aorta E!:I.

=

(RighI) Sagillal TI WI MR depicts disccctomy and bone graft placement at C3-4 through CS-6. There is posterior displacement of graft components

into

ventral epidural space, producing spinal cord

compression

Brachial Plexus Traction Injury

=.

Brachial Plexus Traction Injury (Lefl) Coronal STIR MR in an infant with right arm

paralysis following difficult obstetrical delivery demonstrates right C6 and C7 nerve raal avulsion

pseudorncningoceles

m.

(RighI) Axial T2' eRE MR shows right CB and TI nerve

rool/ventral primary ramus stretch injuries resulting in marked nerve root enlargement and abnormal T2 hyperintensity.

Infarction,

Spinal Cord

Abscess/Myelitis,

Spinal Cord (Left) SagiHal T2WI MR in a patient manifesting post-operative paraplegia following thoracoabdominal aneurysm repair shows abnormal T2 hyperintensity extending from mid La distal thoracic spinal cord (RighI) SagiHal TI C+ MR shows intramedullary rim-enhancing spinal cord abscess with adjacent Jow signal intensity edema.

=.

II 1 35

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CHRONIC BACK PAIN/RADICULOPATHY, POST-OPERATIVE

Q. (/)

,

rJ)

c

co

~ Q)

c Q. (/)

DIFFERENTIAL DIAGNOSIS Common • Failed Back Surgery Syndrome • Peridural Fibrosis • Intervertebral Disc Herniation, Recurrent • Degenerative Disc Disease • Instability • Post-Laminectomy Spondylolisthesis • Accelerated Degeneration Less Common • Hardware Failure • Bone Graft Complications • Vertebroplasty Com pJications • Post-Operative Infection • Scoliosis, Degenerative Rare but Important • Arachnoiditis, Lumbar • Arachnoiditis Ossificans, Lumbar

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Careful clinical exam will often distinguish radiculopathy from mechanical back pain, enabling a tailored differential list • Carefully consider hardware failure or indolent infection in post-operative implant patients presenting with chronic back pain

II 1 36

Helpful Clues for Common Diagnoses • Failed Back Surgery Syndrome o Continued low back pain ± radicular pain following lumber spinal surgery o Myriad etiologies manifest clinically as failed back surgery syndrome (FBSS) o Look for specific abnormal imaging findings that may be addressed clinically • Peridural Fibrosis o Scar formation within epidural space following lumbar spinal surgery o Subset of FBSS o Tl C+ FS MR imaging increases sensitivity for detecting peridural fibrosis and permits differentiation of fibrosis from disc herniation • Intervertebral Disc Herniation, Recurrent o Focal extension of disc material beyond endplate margins at previously operated intervertebral disc level o Subset of FBSS

T1 C+ FSMR imaging increases sensitivity for detecting peridural fibrosis and permits differentiation of fibrosis from disc herniation • Degenerative Disc Disease o Generalized and multifactorial process affecting discovertebral unit leading to biomechanical/morphologic alterations o Imaging diagnosis of degenerative disc disease does not distinguish symptomatic from asymptomatic levels • May be asymptomatic or associated with back/neck pain ± radiculopathy • Instability o Loss of spine motion segment stiffness, where applied force produces greater displacement than normal, producing pain/deformity o Deformity increases with motion and increases over time o Any spinal motion segment (comprised of two adjacent vertebrae, disc and connecting spinal ligaments) may be involved • Most common at post-operative levels, particularly if posterior elements removed by laminectomy o AP translation at unstable level may vary from few mm to entire width of vertebral body • Post-Laminectomy Spondylolisthesis o Loss of spine motion segment stiffness, where applied force produces greater displacement than normal, producing pain/deformity o AP canal diameter narrows at subluxation level, distinguishing from spondylolysis where the AP canal diameter is increased • Accelerated Degeneration o Synonyms include spinal "transitional degenerative syndrome" and "accelerated segmental degeneration" o Degeneration of disc space/facets at level(s) adjacent to spinal fusion 2° to altered biomechanical forces - degenerative disc changes, disc herniation, and/or subluxation o Identical changes occur at motion segments above or below congenital segmentation anomaly levels o

CHRONIC BACK PAIN/RADICUlOPATHY, Helpful Clues for less Common Diagnoses • Hardware Failure o Mechanical breakdown or malfunction of spinal fusion hardware o Malposition of spinal fusion hardware without mechanical failure of implant o Presentation symptoms range from indolent with chronic pain to calamitously with acute pain • Bone Graft Complications o Abnormal alignment, position, or placement of graft or hardware ± associated neurologic deficit, instability, infection • Graft migration, graft displacement, or graft extrusion o Cervical> thoracic> lumbar • Vertebroplasty Complications o Complication types include • Extravasation of cement into spinal canal, neural foramen, or vertebral venous plexus • Pulmonary embolization of cement • Vertebral osteomyelitis • "Bounce back" fracture adjacent to vertebroplasty level • Post-Operative Infection o Infectious sequelae following operative procedures o Most frequently begins in intervertebral disc space ~ disci tis, epidural abscess, subdural abscess, &/or paraspinal abscess

POST-OPERATIVE

Look for unexpected abnormal MR enhancement post-spinal surgery imaging • Scoliosis, Degenerative o "De novo" scoliosis o Lateral spinal curvature due to degenerative disc and facet disease o Radiculopathy secondary to foraminal narrowing and nerve root compression o Usually seen in older patients o

Helpful Clues for Rare Diagnoses • Arachnoiditis, Lumbar o Post-inflammatory adhesion and clumping of cauda equina nerve roots in thecal sac o Imaging shows either absence of discrete nerve roots ("empty sac") or peripheral displacement of nerve roots in thecal sac • Arachnoiditis Ossificans, Lumbar o Intradural ossification associated with post-inflammatory adhesion and clumping of lumbar nerve roots o Look for focal calcific density on CT or hyperintensity on TlWI and T2WI within lumbar nerve root aggregate

II Sagittal T7 C+ MR shows

large recurrent

L4-S disc

T7WI MR shows large osteophyte at U-4 compressing thecal sac and prior multilevel laminectomies. High signal within thecal sac is

herniation compressing thecal sac E2 with thin peripheral enhancement. Note linear enhancement

residual from prior

within disc due £0 disc degeneration

Sagittal

=

Panlopaque

myelography.

=.

1 37

CHRONIC

co

BACK PAIN/RADICUlOPATHY,

POST-OPERATIVE

~ a. CfJ, en c co ~

I-

al C

a. m

Peridural Fibrosis

Peridural Fibrosis

Intervertebral Disc Herniation, Recurrent

Intervertebral Disc Herniation, Recurrent

Intervertebral Disc Herniation, Recurrent

Intervertebral Disc Herniation, Recurrent

(Left) Axial TI C+ MR shows a large amount of homogeneously enhancing left lateral epidural fibrosis surrounding thecal sac and exiting root =:I. (Right) Axial TI C+ MR demonSlrates exuberant

enhancing

epidural fibro.;is circumferenlially surrounding the thecal sac =:I. Note metal artifact

(rom

intervertebral fusion cages

Sli

(Left) Sagittal TI C+ MR demonstrates post-operative changes following L4 & L5 laminectomies. Absence of enhancement helps distinguish

recurrent

L4-5

disc herniation lID from epidural scar tissue. (Right) Axial TI C+ FS MR demonstrates post-operative laminectomy changes with recurrent left L4-5 paracentral disc extrusion =:I. Note absence of disc fragment

enhancement.

(Left) Sagittal TI C+ MR shows a recurrent intervertebral disc herniation =:I following decompressive laminectomy. so(t tissue enhancement

of paraspinal

muscles is common in subacute period. (Right) Axial TI C+ FS MR after L5 left hemilaminectomy shows large recurrent L5-S 1 disc extrusion/free

Fragment with

variant peripheral enhancement lID.

II 1 38

CHRONIC

Bone Graft Complications

BACK PAIN/RADICULOPATHY,

Post-Operative

POST-OPERATIVE

Infection (Left) Axial NECT in a patient with right back and flank pain and palpable mass demonstrates protrusion of colon and mesenteric Fat through the large right iliac wing bone graft harvest site (Right) SagiILal T 1 C+ MR following upper lumbar

=.

decompressive laminectomy shows extensive mufti/evel degenerative disc changes and large dorsal epidural abscess at lumbosacral junction.

=

Post-Operative

Infection

Scoliosis, Degenerative (Left) Axial T1 C+ MR in a patient with chronic back pain SlaWS post explantation of spinal fusion hardware shows enhancing muscle changes of pyomyositis as well as pus and inflammawry phlegmon in operative bed and pedicle screw track 7,. (Right) Anteroposterior radiograph shows multilevel degenerative disc and facet disease producing degenerative scoliosis.

=

Arachnoiditis,

lumbar

Arachnoiditis Ossificans,

lumbar (Left) Sagittal bone CT after myelography shows a large soft tissue intradural filling defect that engulfs the distal cauda equina =>

=

chronic

inflammatory

pseudomass of arachnoiditis. (Right) Axial NECT shows irregular calcification involving the distal thecal sac at the sacral level indicating end-stage calcific

=.

arachnoiditis

(similar to

bone, less dense than Panwpaque).

II 1 41

ro

ACUTE UPPER EXTREMITY

PAIN/WEAKNESS

~

Cl. (fJ

enc

ro ~

IQ.)

c c.

(fJ

DIFFERENTIAL DIAGNOSIS Common • Intervertebral Disc Herniation o Intervertebral Disc Herniation, Cervical o Intervertebral Disc Herniation, Traumatic • Cervical Fracture with Nerve Compression o Burst Fracture, Cervical o Hyperflexion Injury, Cervical o Lateral Flexion Injury, Cervical o Hyperflexion-Rotation Injury, Cervical o Pathologic Vertebral Fracture Less Common • Syringomyelia • Traumatic Dural AVFistula • Peripheral Neuropathy o Brachial Plexus Traction Injury o Radial Neuropathy o Ulnar Neuropathy o Median Nerve Entrapment o Suprascapular erve Entrapment • Infection o Abscess, Paras pinal o Abscess, Epidural o Osteomyelitis, Granulomatous o Osteomyelitis, Pyogenic Rare but Important • Idiopathic Brachial Plexus Neuritis • Acute Transverse Myelitis, Idiopathic • Secondary Acute Transverse Myelitis • ADEM, Spinal Cord

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Careful clinical exam distinguishes radiculopathy from mechanical back pain or myelopathy, limiting pertinent differential diagnosis list

II 1 42

Helpful Clues for Common Diagnoses • Intervertebral Disc Herniation o Intervertebral Disc Herniation, Cervical • Localized « 50% of disc circumference) displacement of disc material beyond edges of vertebral ring apophyses • Clinical symptoms affected by level, location, herniation size o Intervertebral Disc Herniation, Traumatic • Disc herniation following trauma

• Muscle, ligamentous injuries suggest etiology • Cervical Fracture with Nerve Compression o Burst Fracture, Cervical • Typically mid- or lower cervical spine • Axial compression - comminuted fracture extending through both end plates o Hyperflexion Injury, Cervical • Typically mid or lower cervical spine • Flexion force disrupts capsular & posterior ligaments - anterior vertebral displacement/angulation, focal kyphosis, t space between spinous processes o Lateral Flexion Injury, Cervical • Typically mid or lower cervical spine • Articular mass fracture ± fractures of transverse and uncinate processes, vertebral body o Hyperflexion-Rotation Injury, Cervical • Typically mid or lower cervical spine • Traumatic disruption of cervical spine (ligaments ± bony elements) - facet subluxation, focal vertebral angulation, rotation o Pathologic Vertebral Fracture • Fracture through abnormal bone weakened by tumor or infection • Search for trabecular and cortical bone destruction, spinal cord &/or nerve root compression Helpful Clues for Less Common Diagnoses • Syringomyelia o Expanded spinal cord with central dilated, beaded, or sacculated cystic cavity • Traumatic Dural AV Fistula o AVFnidus with enlarged draining veins o Radiculopathy 2° to nerve compression by enlarged epidural veins • Peripheral Neuropathy o Brachial Plexus Traction Injury • Stretch injury or avulsion of ~ 1 cervical roots, brachial plexus elements • Denervation changes in dorsal paras pinal muscles, arm and forearm muscles innervated by terminal peripheral nerve branches o Radial Neuropathy • Focal radial nerve enlargement, abnormal T2 hyperintensity

ACUTE UPPER EXTREMITY • Characteristic entrapment locations include mid humeral shaft or fibrous arch of Frohse o Ulnar Neuropathy • Focal ulnar nerve enlargement, abnormal T2 hyperintensity • Most common in cubital tunnel (elbow); uncommon in Guyon tunnel (wrist) or brachial plexus o Median Nerve Entrapment • Focal median nerve enlargement, abnormal T2 hyperintensity • Entrapment most common at carpal tunnel or pronator teres muscle o Suprascapular Nerve Entrapment • Mass impinges nerve at spinoglenoid or suprascapular notch • Abnormal T2 hyperintensity in denervated muscles • Infection o Abscess, Paraspinal • Paravertebral enhancing phlegmon or peripherally enhancing liquified pus collection o Abscess, Epidural • Spondylodiscitis with adjacent enhancing epidural phlegmon ± peripherally enhancing fluid collection • May extend over many vertebral segments o Osteomyelitis, Granulomatous • Tuberculosis or brucellosis most common

PAIN/WEAKNESS

o

• May produce spinal cord, nerve compression Osteomyelitis, Pyogenic • Ill-defined abnormal vertebral marrow signal centered at disc with loss of adjacent end plate definition • May produce spinal cord, nerve compression

Helpful Clues for Rare Diagnoses

• Idiopathic Brachial Plexus Neuritis o Parsonage-Turner syndrome o Immune-mediated neuropathy of brachial plexus o Smooth enlargement of brachial plexus elements, mild diffuse nerve and muscle enhancement • Acute Transverse Myelitis, Idiopathic o Inflammatory lesion involving both spinal hemicords - bilateral motor, sensory, and autonomic dysfunction o Lesion extent> 2 vertebral segments + eccentric enhancement • Secondary Acute Transverse Myelitis o Inflammatory disorder of spinal cord associated with many etiologies o T2 hyperintense lesion with mild cord expansion, minimal to no enhancement • ADEM, Spinal Cord o Para/postinfectious immune-mediated inflammatory disorder of spinal cord white matter o Multiple sclerosis mimic

II T2WI MR demonslIates a C4-5 cervical disc herniation with spinal cord deformation. location corresponds with left arm pain. Sagittal

Axial T2* eRE MR shows a large left C6-7 cervical

herniation

with

deformation of

concordant

with clinical

localization

disc

the spinal cord

1

of leh arm pain.

43

ACUTE UPPER EXTREMITY PAIN/WEAKNESS

~ Q. (fJ, (/)

C

~ GI

c '0. (fJ

Intervertebral Disc Herniation, Cervical

Intervertebral Disc Herniation, Traumatic

(Left) Axial T2WI FS MR in a

patient

with

leFtarm pain

shows a small cervicalllNP E!lI with abnormal asymmetric T2 hyperintensity of the irritated left C7 nerve root (Right) Sagittal T2WI MR shows ligamentous injury with herniated C6-7 disc 8l disruption of anterior longitudina/l:i4 posterior longitudinal and interspinous ligaments P.::J.

=.

=-

Burst Fracture, Cervical (Left) Axial T2WI FS MR demonstrates a sagittally oriented

burst fracture

=

through the C5 vertebral body with extensive marrow and soft tissue edema.

(Right) Axial bone CT reveals

a C6 burst fracture with right facet capsular

injury and

narrowing of the right C6 neural foramen.

Lateral Flexion Injury, Cervical (Left) Sagittal T2WI MR depicts a traumatic hyped/exion cervical spine injury with right C5-6 facet perch It] and concordant right C6 radiculopathy. (Right) Axial T2WI MR reveals isolated fracture involving right C7 articular pillar and transverse process The fracture was much more conspicuous on CT (not shown) than MR.

=.

II 1 44

ACUTE UPPER EXTREMITY PAIN/WEAKNESS

VI

"C

:J (l)

-I

Q] :J

lateral

Flexion Injury, Cervical

Pathologic Vertebral

Fracture (Left) Axial T2WI MR demonstrates a right C6-7 facet fracture and

=

'"en,

"C

~. OJ

extensive sort tissue edema in patient with lateral compression/stretch injury and right arm pain. (Right) Axial TI C+ FS MR shows a pathological fracture line through a cervical renal cell carcinoma lytic metastasis with acute right arm pain.

=

Traumatic

Dural AV Fistula (Left) Sagittal T2WI MR

shows a large cervicothoracic syrinx in a symptomatic child with Chiar; 1 malformation. Heterogeneous signal intensity within the syrinx cavity reflects dynamic CST pulsation artifact. (Right) Sagittal T2WI MR shows dilated epidural plexus flow voids in a patient with healed C2 fracture complaining of "leaky plumbing II sound in his head, right arm pain, and multilevel arm weakness.

=

Brachial Plexus Traction Injury (Left) Axial T2WI MR demonstrates abnormal enlargement and T2 hyperintensity of the right C8 and TI Ell nerve roolS and ventral primary rami following stretch injury. (Right) Axial STIR MR in a patient with radial neuropraxic injury ("Saturday night palsy") reveals marked abnormal nerve T2 hyperintensity equal to that of regional vessels B.

=

=

II 1 45

ro

ACUTE UPPER EXTREMITY

~ (fJ,

PAIN/WEAKNESS

Q.

(/)

c

ctl ~ I-

Ulnar Neuropathy

(l)

c Q.

en

=

anteriorly and nerve heterogeneous intensity.

=

is

in signal

Suprascapular

rs

fLeft) Axial T1 C+ MR demonstrates a large rim-enhancing cyst producing adjacent scapular erosion. Diffuse

=

enhancement of the infraspinatus muscle

secondary to acute denervalion is visible ~J. (Right) Axial T 1 C+ MR with vertebral osteomyelitis shows extensive enhancement of pre vertebral phlegmon SI and peripheral enhancement of ventral epidural abscess de/orming the spinal cord

=

(Left) Sagillal T 1 C+ MR (chronic coccidiomycosis) shows destruction of C7, T1 bodies and large preverrebral abscess with relative sparing of the intervertebral discs. (RighI) Axial T1 C+ MR (chronic coccidiomycosis) depicts a large prevertebral abscess ~ with adjacent osseous destruction and soft tissue inflammation engulfing exiting nerve roots.

=

II 1 46

Median Nerve Entrapment

(Left) Axial T2WI FS MR reveals internal ulnar nerve architectural distortion at cubital tunnel with abnormally enlarged hyperintense nerve Fascicles and regional perineural soft !issue edema. (Right) Axial STIR MR depicts MR appearance of abnormal median nerve in the carpal tunnel. The flexor retinaculum is bowed

Nerve Entrapment

Abscess, Epidural

ACUTE UPPER EXTREMITY PAIN/WEAKNESS

fJl -C ::::J

-l

~ Ql ::::J

,

(f> (f)

(Left) Sagittal T1 C+ MR in an IV drug abusing patient

u

~ Ql

with neck pain and {ever

shows destructive changes of C4-5 disc space with marrow enhancement,

focal

kyphosis, and epidural phlegmon. (Right) Axial T1WI FS MR demonstrates extensive

marrow

and soft

tissue inflammalOry

changes

in a patient with vertebral pyogenic osteomyelitis and arm pain.

(Left) Coronal oblique STIR MR (Parsonage·Turner

syndrome) demonstrates abnormal T2 signal hyperintensity and enlargement of the right brachial plexus neural elements =:S. (Right) Sagittal T1 C+ MR reveals multilevel spinal cord swelling and

abnormal intramedullary enhancement

involving both

gray and white maller.

ADEM, Spinal Cord

ADEM, Spinal Cord (Left) Sagittal T2WI MR in a pediatric patient developing right leg weakness following a viral illness several I'veeks previously shows multiple patchyexpansile intramedullary T2 hyperintense lesions. (Right) Axial T1 C+ MR depicts a typical case of monophasic spine AOrM lesions with abnormal intramedullary enhancement

=.

II 1 47

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c

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IQ)

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en

LOWER EXTREMITY PAIN

DIFFERENTIAL DIAGNOSIS Common • Intervertebral Disc Bulge • Intervertebral Disc Herniation • Stenosis, Acquired Spinal, Lumbar • Stenosis, Foraminal, Lumbar • Stenosis, Congenital Spinal • Spondylolisthesis • Spondylolysis • Metastases Less Common • Abscess, Epidural, Paravertebral • Hematoma, Epidural-Subdural • Ependymoma, Myxopapillary, Spinal Cord • Neurofibroma • Schwan noma • Facet Joint Synovial Cyst • Arachnoiditis, Lumbar • Primary Bone Tumor o Multiple Myeloma o Osteoid Osteoma/Osteoblastoma o Osteosarcoma o Chondrosarcoma • Femoral Neuropathy • Retroperitoneal Hematoma • Tethered Spinal Cord

•

•

•

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Majority of lower extremity pain due to pathology within the extremity o Osteoarthritis of the hip or knee o Meniscal pathology o Tendinous or ligamentous injury o Trauma o Deep venous thrombosis o Infection/inflammation o Neoplasms of the soft tissues and bone • Neurogenic leg pain due to impingement on the distal cord or nerve roots in the spinal canal, neuroforamina, or retroperitoneum • Also consider vascular claudication as a remote source of lower extremity pain

II 1 48

Helpful Clues for Common Diagnoses • Intervertebral Disc Bulge o Diffuse (> 50% circumference) extension of the disc beyond its normal margins • Intervertebral Disc Herniation o Classified morphologically

•

•

• Protrusion: Wider than deep, limited by adjacent endplates on sagittal images • Extrusion: Deeper than wide or extends beyond either adjacent end plate on sagittal images • Sequestration: Herniated disc not in continuity with the remaining disc Stenosis, Acquired Spinal, Lumbar o Multifactorial process o Relative lumbar canal stenosis: < 12 mm; absolute lumbar canal stenosis: < 10 mm Stenosis, Foraminal, Lumbar o Multifactorial process o Loss of fat within the neural foramen on sagittal T1WI Stenosis, Congenital Spinal o Developmental narrowing of the lumbar canal and neural foramina due to short, squat pedicles o Otherwise mild degenerative changes in disc and posterior elements can result in symptomatic stenosis Spondylolisthesis o Displacement of a vertebral body relative to the inferior vertebra o Direction • Anterolisthesis • Retrolisthesis, usually degenerative etiology • Lateral listhesis o Etiology • Degenerative, secondary to loss of intervertebral disc height and laxity in facet joints • Spondylolytic • Traumatic Spondylolysis o Defect of pars interarticularis, may be unilateral or bilateral o Classified into early, progressive, and terminal stages (Morita) o Hairline fracture of early stage often difficult to appreciate with CT • Fracture can be suggested by MR (hyperintense STIR) or SPECT (tracer avid) o Unilateral spondylolysis associated with increased risk of contralateral pars fracture Metastases o Common primaries: Breast, lung, kidney, prostate

LOWER EXTREMITY PAIN

CIl "C

::::l (1)

o o

Lesions typically multiple Either lytic or sclerotic on CT, typically hypointense Tl/hyperintense T2 signal on MR

o

Either epidural tumor or pathologic vertebral compression fracture can impinge on nerve roots or the cord

Helpful Clues for Less Common Diagnoses • Abscess, Epidural, Paravertebral o Epidural fluid collection with marked peripheral enhancement o Usually in the setting of discitis-osteomyelitis due to pyogenic or mycobacterial infection o Can also be seen with inoculation arising from surgery or instrumentation (e.g., epidural catheter placement) • Hematoma, Epidural-Subdural o MR signal of blood products varies with age o Subacute hemorrhage sometimes difficult to differentiate from epidural fat on both T1 and FSET2 (another use for STIR) • Ependymoma, Myxopapillary, Spinal Cord o Most common tumor of the conus medulJaris and lumbosacral canal o Marked enhancement typical o Can show signs of necrosis and hemorrhage o Bony remodeling when large: Scalloping of the margins of the spinal canal, foraminal enlargement

Intervertebral

• Neurofibroma and Schwannoma o Both can manifest as a transforaminal ("dumbbell") mass o Foraminal enlargement due to remodeling • Facet Joint Synovial Cyst o Circumscribed, cystic lesion associated with a degenerative facet joint o Can cause canal stenosis and impinge on the ipsilateral traversing or exiting nerve root • Arachnoiditis, Lumbar o Usually a post-surgical complication o Clumping of nerve roots, "empty sac sign", calcification (unusual) • Tethered Spinal Cord o Cord normally terminates above the L2-3 level o Causative lesions • Tight filum terminale • Dysraphism • Diastematomyelia

-I

iiJ ::::l en, en -0 OJ

0;'

Disc Bulge

II Axial T2WI MR shows eccentric disc bulge ~ with extraforaminal impingement on a swollen left L5 nerve root~.

Sagittal T1WI MR shows intraforaminal disc extrusion completely effacing the fat within the L5-S1 neural foramen=.

1 49

lOWER

C'
EXTREMITY PAIN

~

c.

(/J

en c ~

C'
IeI)

c c. (/J

Stenosis, Acquired Spinal, lumbar (Left) SagieealT2WI MR shows advanced degenerative changes with moderate-La-severe canal stenosis at multiple levels of ehe lumbar spine A/50 seen is hemangioma in L 1 vertebral body (Right) Sagittal T7WI MR shows moderalely severe /.5-51 foraminal stenosis due to endplaee osteophyte and

=.

=

roslrocaudal

facet

subluxation. L4-5 foramen is narrowed by disc bulge and facee hypertrophy. Noee healed fracture of Ihe L4 pedicle 1J:iJ.

Spondylolisthesis (Left) Axial T2WI MR shows a narrowed AP diameter of ehe lumbar canal wieh short Ihickened pedicles (Right) Laeeral myelography sholVs bilateral L5 spondylolysis and a pronounced L5-S I spondylolisehesis There is abrupe cue-off filling in the caudal ehecal sac due COehe resulting canal stenosis ~.

=.

=.

Spondylolysis (Left) Sagittal T2W/ MR shows a defece of ehe left L3 pars interarticularis 7] with mild anterior displacement of L3 on L4, resulting in moderately severe narrowing of the L3-4 neural foramen (Right) Axial T7 C+ MR shows T 12 renal cell carcinoma metastasis with extensive epidural component compressing the conus medul/aris

=.

=.

II 1 50

Metastases

LOWER EXTREMITY PAl N

Abscess, Epidural, Paravertebral

Hematoma,

Epidural-Subdural (Lefl) Sagittal T/ C+ MR shows ventral epidural abscess resulting in marked canal stenosis at the L5 level ~. (RighI) Sagittal T2WI MR shows dorsal epidural hematoma from T 12-L] causing severe canal stenosis

=-

and compressing the conus and cauda equina.

Ependymoma,

Myxopapillary, Cord

Spinal Schwannoma (Left) Sagittal T 1 C+ MR shows a large, heterogeneously enhancing mass essentially filling the caudal thecal sac from L2 through L5 (RighI) Axial T2WI MR shows right T/2-L7 lransforaminal mass, with heterogeneously hyperintense signal, expanding the neural foramen causing severe

=.

canal stenosis and compression medullaris

Facet Joint Synovial Cyst

Arachnoiditis,

of the conus

=.

Lumbar (Lefl) Axial T2WI MR shows a cystic lesion in the right

a.

lateral lumbar canal in contact with a degenerated right L4-5 facet joint, resulting in canal stenosis and compression of the exiling right L5 nerve root (not shown). (RighI) Axial T2WI MR shows peripheral clumping of nerve roots in the distal thecal sac, resulting in the "empty sac sign", Note laminectomy at this level.

II 1 51

BACK PAIN, ADULT

ro

~ a. CfJ, rJ)

c ro ~

fOl

c a.

en

DIFFERENTIAL DIAGNOSIS Common • Intervertebral Disc Bulge • Intervertebral Disc Herniation • Facet Arthropathy • Intervertebral Disc Anular Tear • Stenosis, Acquired Spinal • Spondylolysis • Spinal Muscle Injury • Instability • Benign Compression Fracture • Schmorl Node Less Common • Osteomyelitis, Pyogenic • Osteomyelitis, Granulomatous • Metastatic Disease • Insufficiency Fracture, Sacral • Obstructive Uropathy Rare but Important • Ependymoma, Myxopapillary, Spinal Cord • Primary Bone Tumor o Multiple Myeloma o Osteoid Osteoma/Osteoblastoma o Osteosarcoma o Chondrosarcoma • Aortic Aneurysm • Marrow Replacement Processes o Sickle Cell o Leukemia o Thalassemia o Mucopolysaccharidoses

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Back pain is a major health and economic problem in the industrialized world • Substantial burden to the healthcare system and to the economy as a whole due to lost productivity (disability, absenteeism) • Back pain is the most common indication for imaging of the spine • Most common causes of back pain are those relating to degenerative changes in the intervertebral discs and facet joints

II 1 52

Helpful Clues for Common Diagnoses • Intervertebral Disc Bulge o Diffuse (> 50% circumference) extension the disc beyond its normal margins

of

• Intervertebral Disc Herniation o Classified by morphology as protrusion, extrusion, or sequestration • Facet Arthropathy o Joint space narrowing, osteophyte formation o Often accompanied by ligamentous hypertrophy o May be secondary to altered load bearing in the setting of degenerative disc disease, by which it is almost invariably accompanied o "Blocky" facet morphology does not necessarily represent degenerative change • Intervertebral Disc Anular Tear o Focal T2 hyperintensity in dorsal disc margin, representing disruption of the anulus fibrosus o May enhance on post-contrast sequences o Relatively frequent finding; majority are asymptomatic • Stenosis, Acquired Spinal o Narrowing of the spinal canal o Multifactorial 0< 10 mm diameter of the lumbar canal is absolute stenosis • Spondylolysis o Defect of pars interarticularis, may be unilateral or bilateral o Classified into early, progressive, and terminal stages (Morita) o Hairline fracture of early stage often difficult to appreciate with CT; can be suggested by MR (hyperintense STIR) or SPECT (tracer avid) o Unilateral spondylolysis associated with increased risk of contralateral pars fracture (e.g., terminal spondylolysis on one side with early/symptomatic spondylolysis on the other) • Spinal Muscle Injury o Muscular strain, with variable degrees of edema/hemorrhage and disruption o Best visualized on fat-saturated T2 sequences • Instability o Greater displacement than normal for a given force through a spinal motion segment resulting in a diminished ability of the vertebral column to protect the spinal cord and nerve roots

BACK PAIN, ADULT Multifactorial Dynamic instability: > 3 mm motion between flexion and extension • Benign Compression Fracture o Due to axial loading injury, especially through osteoporotic bone o No or minimal radial expansion of vertebral circumference o Horizontal fracture plane; sclerotic band on Cl~ band-like or triangular T2 hyperintensity on sagittal MR o Anterior wedging common; posterior cortex usually intact and neural arch spared o Differentiation of benign from pathologic compression fracture is often not straightforward • Schmorl Node o Herniation of nucleus pulposus into an adjacent vertebral body through an end plate defect o o

Helpful Clues for Less Common Diagnoses • Osteomyelitis, Pyogenic o Early disc space destruction, with hyperintense T2 signal and enhancement o Type I signal in adjacent endplate marrow with enhancement on post-contrast sequences (MR) o Endplate demineralization and destruction (CT)

Intervertebral

Disc Herniation

Infiltrative soft tissue signal/attenuation in epidural space &/or displacing normal paravertebral fat; may develop into epidural/paravertebral abscess • Osteomyelitis, Granulomatous o Infection due to tuberculosis or other granulomatous disease (e.g., brucellosis) o Destruction of bone with relative sparing of the disc o Large psoas abscesses o Large prevertebral abscesses dissecting extensively below the anterior longitudinal ligament • Metastatic Disease o Common primaries: Breast, lung, kidney, prostate o Lesions typically multiple o Either lytic or sclerotic on CT, typically hypointense T1/hyperintense '1'2signal on MR o Extraosseous extension may occur into the epidural or paravertebral spaces o May cause pathologic vertebral fracture • Insufficiency Fracture, Sacral o Diagnosis often an unexpected finding on MR of the lumbar spine o Unilateral or bilateral vertical fractures through the sacral ala ± horizontal fracture through the body o Linear hypointensity on '1'1WI in the fracture, '1'2hyperintensity appreciated best on fat-saturated sequences (e.g., STIR) o

Facet Arthropathy

II Axial T1WI MR shows a large extruded disc fragment in the left antem/ate,al epidural space at the L4 leve/!:ll.

=-

Axial NEeT shows severe degenerative changes in the facet joints at the L4·5 level with joint space narrowing, irregularity, and osteophyte formation.

1 53

BACK PAIN, ADULT

ro

~ <>CfJ, (/)

c

ro ~

f-

a>

c Co

CfJ

Intervertebral

Disc Anular Tear

(Left) Sagittal STIR MR shows focal T2 hyperintensity in the dorsal margins of the L4-s and L5-s1 discs demonstrating presence of anular tears. Type I degenerative marrow change is seen adjacent to the L4- 5 disc 81. (Right) Axial T1 WI MR shows severe central

=

canal stenosis due to diffuse

disc bulging effacing the ventral thecal sac 8l and posterior

facet degenerative

arthropathy ~ and right-sided ligamentous hypertrophy

=.

Spinal Muscle Injury (Left) Sagittal NECT shows (unilatera/) L5 pars fracture with corticated margins ffi demonstrating

presence

of

terminal spondylolysis with pseudoarthrosis. (Right) Axial STIR MR shows hemorrhage and edema in the right paraspinous musculature

=.

Benign Compression (Left) Sagittal T1WI MR shows loss of height and anterior wedging of the L 1 body ~ with mild canal

compromise due to retropulsed bony elements in this patient who suffered an axial loading injury six months previously. (Right) Sagittal T1 C+ MR shows peripherally enhancing fluid collection replacing the L5-s1 disc space ventral epidural and paravertebral phlegmon, and dorsal epidural abscess ~ in this intravenous drug abuser.

=-

II 1 54

Fracture

BACK PAIN, ADULT

Osteomyelitis,

Granulomatous

Metastatic Disease (Left) Axial T7 C+ MR shows pathologic marrow enhancement with large epidural and bilateral psoas abscesses PJ:ll. (Right) Axial T 1 C+ MR shows vertebral melanoma metastasis with epidural extension causing severe

=

-=

canal stenosis and cord compression.

Insufficiency Fracture, Sacral

Multiple Myeloma (Left) Sagittal STIR MR shows cortical disruption and hyperintense signal lhrough the second sacral segment representing lhe horizontal component of a sacra! insufficiency fracture. (Right) Sagittal T 1 WI MR shows mulliple hypointense

=-

vertebral lesions, some

=-

indicated with in this patient with multiple myeloma.

Osteosarcoma

Sickle Cell (Left) Axial CECT shows a lytic vertebra/lesion with infiltrative margins and a

large extra osseous component

m arising

from

Pagetic bone of the L4 vertebral body. (Right) Coronal NECT shows diffusely sclerotic marrow spaces due to multiple bone infarcts and the characteristic central endplate compression deformities ~ of sickle cell anemia.

II 1 55

BACKPAIN, PEDIATRIC

ctl

~ Cl. (fJ, en c

DIFFERENTIAL DIAGNOSIS

ctl

t= Q)

c Co

en

Common • Scoliosis a Scoliosis, Idiopathic a Scoliosis, Neuromuscular a Scoliosis, Congenital • Trauma a Fracture a Spinal Muscle Injury, Traumatic • Syringomyelia • Spondylolysis • Scheuermann Disease Less Common • Stenosis, Congenital Spinal • Guillain-Barre Syndrome • Neoplasm a Leukemia a Neuroblastic Tumor a Ewing Sarcoma a Ependymoma, Myxopapillary, Spinal Cord a Metastases, CSF Disseminated a Metastases, Hematogenous a Osteoid Osteoma a Langerhans Cell Histiocytosis • Osteomyelitis a Osteomyelitis, Granulomatous a Osteomyelitis, Pyogenic Rare but Important • Intervertebral Disc Herniation • Acute Transverse Myelitis, Idiopathic • Secondary Acute Transverse Myelitis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Clinical history, physical examination, and appropriate laboratory investigations constrains differential considerations

II 1 56

Helpful Clues for Common Diagnoses • Scoliosis a Scoliosis, Idiopathic • Usually sigmoid S-shaped • Pelvic tilt => limb-length discrepancy • No vertebral segmentation anomalies a Scoliosis, Neuromuscular • C-shaped curvature common • Baclofen infusion device clue if present a Scoliosis, Congenital

•

•

•

•

• Vertebral segmentation and formation anomalies • Rib fusions, pedicular bars => more likely progressive curvature Trauma a Fracture • Similar criteria to adults a Spinal Muscle Injury, Traumatic • MR or CT best for diagnosis • T2WI FSMR or STIRMR most helpful for diagnosis, determining extent Syringomyelia a Chiari 1 malformation common association in pediatric patients a Always consider traumatic, neoplastic causes • Administer contrast if tumor suspected or nodularity detected Spondylolysis a Unilateral or bilateral; may not see osseous break (stress reaction) a Oblique plain radiographs, MR show osseous defects well a Bone scintigraphy sensitive for detecting stress reaction prior to pars fracture Scheuermann Disease a Most common in adolescent age group a Diagnostic criteria include anterior wedging, kyphosis, endplate irregularity a May see significant kyphosis ± scoliosis

Helpful Clues for Less Common Diagnoses • Stenosis, Congenital Spinal a Reduced AP diameter of central spinal canal a Pedicles are short, thick, and more laterally angled a Predisposes to symptomatic degenerative spine disease at younger age • Guillain-Barre Syndrome a Smooth, linear enhancement of cauda equina and conus pia diagnostic in correct clinical context a If nodular enhancement, consider tumor or granulomatous infection • Neoplasm a Leukemia • Look for "bright disc" sign (marrow infiltration) • Consider NHL in younger patients a Neuroblastic Tumor • Often diagnosed in younger patients

BACK PAIN, PEDIATRIC • Spinal invasion through neural foramina affects surgical treatment planning; MR best for detection o Ewing Sarcoma • Usually adolescent age group • Aggressive destructive or permeative lesion, cellular MR signal characteristics o Ependymoma, Myxopapillary, Spinal Cord • May present with chronic or longstanding back pain • May have extensive intradural metastases at time of diagnosis o Metastases, CSF Disseminated • Consider choroid plexus, pineal region, suprasellar, posterior fossa tumors, glial neoplasms, leukemia/lymphoma • Most commonly seen in brain tumors with intimate CSF contact o Metastases, Hematogenous • Relatively rare • Consider neuroblastoma, lymphoma, and tumors with bone to bone metastatic patterns (Ewing sarcoma, osteosarcoma) o Osteoid Osteoma • Pain classically worst at night • Symptoms alleviated with aspirin o Langerhans Cell Histiocytosis • May mimic neoplasm symptoms, imaging appearance (small, round blue cell tumor) • Classic etiology of severe vertebra plana • Vertebral height often makes surprising recovery after treatment

Scoliosis, Idiopathic

• Osteomyelitis o Osteomyelitis, Granulomatous • May be centered at disc space; TB tends to spare disc space until late in disease process • Look for paravertebral masses with TB o Osteomyelitis, Pyogenic • Frequently centered in intervertebral disc space • Abnormal marrow signal intensity, paraspinal inflammatory mass Helpful Clues for Rare Diagnoses • Intervertebral Disc Herniation o Diagnostic criteria identical to adults • Acute Transverse Myelitis, Idiopathic o Idiopathic inflammatory spinal cord disorder ~ bilateral motor, sensory, and autonomic dysfunction o Central cord lesion extends> 2 vertebral segments (often 3-4 segments), eccentric enhancement o Thoracic> cervical cord (10%) • Secondary Acute Transverse Myelitis o Inflammatory disorder of spinal cord associated with many etiologies o Hyperintense lesion on T2WI with mild cord expansion without significant enhancement o Thoracic> cervical> conus medullaris

Scoliosis, Neuromuscular

II Anteroposterior patient

radiograph in a female adolescent S·shaped idiopathic thoracic

sho\,\ls substantial

dextrosco/iotic curvature with lumbar levoscoliosis.

Anteroposterior radiograph in a cerebral palsy patient with spasUcity shows convex right C-shaped neuromuscular scoliosis. Note baclofen infusion system

1

for spasticity

57

trealmenl.

BACK PAIN, PEDIATRIC

<1l

~ 0(f) , If)

<=

~

<1l

Iell

c: '0. (f)

Scoliosisr Congenital (Left) Coronal bone CT 3D reformats in a VACTERL patient with convex right

spinal curvature demonstrates multiple rib fusions on the left, upper thoracic block vertebra, T7 and T12 hemivertebra 8l and T9 butterfly vertebra PJ::l. (Right) Sagittal T1WI MR in a Chiar;

1 malformation

patient shows a large cervical syrinx. Despite sacculated appearance,

the

syrinx fluid compartments

are in contiguity and would likely respond to a single

catheter drain.

Scheuermann

Disease

(Left) Sagittal bone CT in a pediatric patient with back

pain reveals an L5 pars defect

with minimal of L5 on S I. (Right) Sagittal bone CT in an adolescent patient anterior

subluxation

depicts mullilevel anterior wedging with endplate irregularities

of Scheuermann

disease producing rounded kyphotic thoracic deformity.

Guillain-Barre (Left) Sagittal T2WI MR

demonstrates marked narrowing of lumbar spinal canal anteroposterior

diameter. Anteroposterior canal diameter should normally increase rather than decrease in lower lumbar spine. (Right) Sagittal T1 C+ MR in a patient with

ascending paralysis demonstrales

avid smoolh,

linear enhancemenl

of

venlral conus pia and cauda

equina.

II 1 58

Syndrome

BACK PAIN, PEDIATRIC

Ependymoma, leukemia

Myxopapillary, Cord

Spinal (Left) Sagittal STIR MR in a newly diagnosed patient reveals abnormal hyperintense marrow signal and numerous vertebral compression fractures (Right) Sagittal T1 C+ MR reveals diffuse abnormal intradural ehhancement within thecal sac, obscuring conus termination and cauda equina and distorting normal conus and cauda equina.

=.

Metastases,

CSF Disseminated (Left) Sagittal T1 C+ MR spinal surveillance imaging in a pediatric patient with malignant brain glial neoplasm shows extensive smooth and nodular enhancing intradural drop metastases. (Right) Axial bone CT of the cervical spine demonstrates a well·circumscribed lytic lesion in the expanded right pedicle 1:1:1 with dense central nidus.

Secondary

Acute Transverse

Myelitis (Left) Sagittal T1 C+ fS MR shows C3/4 disc space height loss with fluid signal intensity and abnormal marrow and epidural enhancement adjacent to disc space indicating discitis with osteomyelitis. No spinal cord compression is present (Right) Sagittal T2WI MR associated with acute eNS demyelination demonstrates abnormal intramedullary T2 hyperinlensity extending to conus level (not shown). The areas of abnormality are patchy rather than contiguous.

II 1 59

SIECTION 2 €:raniovertebral Junction Anatomically Based Differentials Cranio-Cervical Junction Acute Injury CVJ Abnormality, General CVJ Soft Tissue Abnormality

11-2-2 11-2-4 11-2-8

Generic Imaging Patterns C1-C2 Instability Odontoid Deformity

11-2-12 11-2-14

c

CRANia-CERVICAL JUNCTION ACUTE INJURY

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~ QJ

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QJ

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U Q)

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en

DIFFERENTIAL DIAGNOSIS Common • Trauma o Odontoid C2 Fracture o Burst Fracture, C2 o Hangman's C2 Fracture o Jefferson C1 Fracture o Occipital Condyle Fracture o Dissection, Vertebral Artery o Traumatic Disc Herniation o Os Odontoideum o Spinal Cord Injury Without Radiographic Abnormality (SCIWORA) • Nontraumatic Mimics o Pathologic Vertebral Fracture o Cran iovertebral Junction Variants o Incomplete Fusion, Posterior Element o Pseudosubluxation C2-3 o Torticollis less Common • Atlanto-Occipital Dislocation • Atlanto-Axial Rotary Subluxation

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • MR very useful to evaluate for ligament injuries o Coronal STIRrarely performed but useful in this region • Coronal, sagittal reformations essential on CT for full evaluation of injury

Odontoid

C2 Fracture

• CT arteriogram equally accurate and faster than MR arthrogram for vertebral dissection o Time is often of the essence in these patients, who tend to have multiple injuries Helpful Clues for Common Diagnoses • Odontoid C2 Fracture o Usually low-velocity injury in elderly • Jefferson CI Fracture o If combined displacement of lateral masses > 6.9 mm, unstable o High likelihood of other fractures: Spine, skull, pelvis, lower extremity • Os Odontoideum o Chronic, nonunited odontoid fracture • Spinal Cord Injury Without Radiographic Abnormality (SCIWORA) o Occurs primarily in children o MR: Injuries to cord, ligaments, intervertebral discs, cartilaginous endplates 02/3 severe cervical injuries in children < 8 years are SCIWORA • Pseudosubluxation C2-3 o Children < 10 years old, anterolisthesis may measure up to 4 mm Helpful Clues for less Common Diagnoses • Atlanto-Occipital Dislocation o High incidence cord injury o Formerly usually fatal; now often survive to hospital

Burst Fracture,

C2

II 2 2

Sagittal NCCT shows type 2 dens fracture 1::1 in an osteoporotic patient. Soft tissue swelling is mild. These fractures are commonly subtle on radiographs and best seen on lateral (not odontoid) vie\oV.

Sagittal bone CT shows comminuted C2 body fracture with characteristic retropulsion of posterior cortex

=.

Additional burst fractures are commonly elsewhere in the spine.

present

CRANia-CERVICAL

Hangman's

C2 Fracture

JUNCTION

ACUTE INJURY

Jefferson Cl Fracture (Left) Sagittal oblique 3D CT shows bilateral C2 pedicle (ractures

=

without

fracture

of vertebral body. Effendi classification uses presence of disruption of C2- 3 disc and facet joints as a measure of the severity of injury. (Right) Axial bone CT shows multiple fractures of C 1 ring 1:':1. Lateral displacement in this patient indicates rupture of transverse ligament of dens and resultant instability.

Occipital

Condyle Fracture

Os Odontoideum (Left) Coronal NECT shows nondisplaced occipital condyle fracture 1:':1 as well as C4 articular pillar fracture reflecting lateral flexion injury. (Rig"') Sagittal bone CT shows chronic, nonuniled dens fracture so-called as odonloideum. This may be unstable, and flexion-extension views should be performed.

a

=-

Craniovertebral

Junction Variants

Craniovertebral

Junction Variants (Left) Axial bone CT shows anterior

and posterior

cfefts

SII of C 7. Smooth, corticated margins are signs distinguishing this from trauma. (Rig"') Sagittal bone CT shows anterior arch of C I fused 10 clivus 1:':1 and posterior arch fused 10 C2 SII.

II 2 3

c

CVJ ABNORMALITY,

o

GENERAL

U C

--,:J <1l

~

.n Q)

t Q)

>

.Q

c <1l

~

U C1l

c

'a.

VJ

II 2 4

DIFFERENTIAL

DIAGNOSIS

Chondrosarcoma Chordoma (Usually Clivus) o Aneurysmal Bone Cyst • Cranial Settling, Platybasia and Basilar Invagination, Acquired o Paget Disease o Rheumatoid Arthritis, Adult o Osteomalacia/Rickets o o

Common • Bone Trauma o Odontoid Fracture, C2 o Burst Fracture, C2 o Hangman's Fracture, C2 o Jefferson Cl Fracture o Occipital Condyle Fracture o Os Odontoideum • Congenital Neural Abnormalities o Chiari 1 Malformation o Chiari 2 Malformation • Congenital Bone and Ligament Abnormalities o Achondroplasia o Craniovertebral Junction Variants o Trisomy 21 o Mucopolysaccharidoses • Arthritis o Osteoarthritis o Rheumatoid Arthritis o Juvenile Idiopathic Arthritis o Spondyloarthropathy, Seronegative o CPPD • Soft Tissue Calcification or Ossification o Calcific Tendinitis, Longus Coli o Spondyloarthropathy, Seronegative o OPLL o CPPD • Extramedullary Mass o Metastases o Lymphoma o Plasmacytoma o Pannus from Rheumatoid Arthritis o Abscess, Epidural, Paravertebral o Osteomyelitis, CI-C2 o Nasopharyngeal Carcinoma o Neurofibromatosis Type 1 o Schwannoma o Paraganglioma o Meningioma • Intramedullary Mass o Syringomyelia o Chiari 1 Malformation o Chiari 2 Malformation o Hemangioblastoma, Spinal Cord o Pediatric Brainstem Glioma • Bone Mass o Metastases o Multiple Myeloma o Osteomyelitis, CI-C2

Less Common • Rotary Subluxation, CI-2 • Atlanto-Occipital Dislocation • Grisel Syndrome • Carotid Dissection/Pseudoaneurysm

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Hint: Differentiate trauma vs. bony congenital variant o Soft tissue swelling usually evident in trauma o Cortication of bone indicates nonacute trauma o Os odontoideum thought to be nonunited fracture, not congenital variant • Hint: Watch for mass adjacent to dens o Pannus from RA: Dens eroded, no calcification o Seronegative spondyloarthropathy: Like RA, plus enthesophytes, joint fusion o Juvenile inflammatory arthropathy: Like adult RA or seronegative spondyloarthropathy • Usually involves multiple levels in cervical spine • Growth disturbance characteristic o CPPD: Calcifications, cysts in bone o Infection: Usually involves disc space • Tuberculosis involves disc space later in course of infection o OPLL, osteoarthritis: No bony erosion o Tumor: Origin in bone, meninges or cord • Hint: Watch for heterogeneous high signal in bone marrow without cortical breakthrough o Myeloma o Lymphoma o Metastases Helpful Clues for Common • Types of C2 fractures o Odontoid Fracture, C2

Diagnoses

CVJ ABNORMALITY, • Type I: Obliquely oriented through tip • Type II: Horizontally oriented through base • Type Ill: Really a fracture of body; horizontally oriented, through body and below base of dens o Burst Fracture, C2 • Axial load injury • Extends through posterior cortex of vertebral body o Hangman's Fracture, C2 • I-Iyperflexion or hyperextension, usually from MVA • Traumatic spondylolisthesis of C2 • Fracture through C2 pedicles • Usually see focal kyphosis and anterolisthesis at C2-C3 • Effendi type I: Traumatic spondylolisthesis isolated • Effendi type II: Also disruption of C2-C3 disc • Effendi type Ill: Also disruption of C2-C3 facet joints o Os Odontoideum • Chronic nonunited fracture • Congenital Bone and Ligament Abnormalities o May be multiple o May be isolated, detected as incidental finding in adulthood o Often cause adjacent premature degeneration • Trisomy 21 o Spinal stenosis

Odontoid

Fracture,

Instability occiput-Cl and CI-C2 o Unlike RA, no erosion of dens • Osteoarthritis o Common at craniocervical junction o Involves synovial articulations: Facet joints, dens/Cl articulation o Dens and anterior arch of Cl develop osteophytes, sclerosis best seen on CT o May have prominent soft tissues posterior to dens but no erosions o Facet osteoarthritis at occiput-Cl or CI-C2 may develop large osteophytes, synovial cysts • Rheumatoid Arthritis o Calcification never present o Pannus heterogeneous signal intensity on MR o Low signal intensity areas on T2Wl mimic crystals, calcification o Almost always see erosion of dens o Early erosion: Loss of subchondral bone plate o Late erosion: Pencilling of dens o Facet erosion: Atlanto-axial impaction o Craniocervical disease does not occur without peripheral disease (hands/feet) • CPPD o Mimics RA on MR, but subchondral bone plate not eroded o Calcifications visible on CT, radiographs o

Burst Fracture,

C2

=.

Sagittal NECT shows type /I odontoid f,acture This fracture usually occurs in elderly patients, often from a ground level fall, and may be missed on radiographs

due to oSleopenia.

GENERAL

=

<-

c OJ

~

o· OJ

C2

Sagiltal NECT shows horizontal and vertical fractures of C2 due to axial load injury.

II 2 5

c

CVJ ABNORMALITY,

o

GENERAL

nc --,:J

ro ~

.0 OJ

t

OJ

> .Q c ro ~ () Q)

c: '0.

In

Chiari 1 Malformation

Chiari 2 Malformation

Craniovertebral Junction Variants

Trisomy 21

Osteoarthritis

Juvenile Idiopathic Arthritis

(Left) SagiHal T2WI MR shows typical peg·shaped

=-

appearance

of cerebellar

tonsils which descend to level of CI arch. 4th ventricle is normal. There is a small syrinx =.:I. (Right) Sagittal T2WI MR shows characteristic

Chiar; 2

features of small posterior fossa and 4th ventricle, medullary kink =.:I and verminal ectopia through foramen

magnum

~.

(Left) Lateral radiograph shows CI =.:I fused to occiput, resulting in dysmorphic CI·C2 articulations and dysmorphic C2 body. Odontoid is triangular in shape !:?:l. (Right) SagiHal bone CT shows OIC2 subluxation 81 without erosions. There was no history of trauma. Marked narrowing

of spinal canal

was symptomatic.

(Left) Sagittal T2WI MR shows apparent mass r.:= posterior to dens which is osteophyte formation. Although OA can mimic mass on MR, diagnosis is straightforward

on CT where

bone spurs are seen. (Right) Sagittal T2WI MR shows cortical margin of odontoid lost anteriorly due to erosions, and 50ft tissue mass ED is due to pannus. Cranial settling is present, with odontoid at level of clivus.

II 2 6

CVJ ABNORMALITY,

GENERAL ()

~ OJ ::::>

Pannus from Rheumatoid

o

Arthritis

<

(Left) Sagittal bone CT shows calcifications and soft tissue fullness II] at craniocervical junction due to CPPD. CPPD of craniocervical

junction

not uncommon

in elderly

C1l

;:l. C1l

0-

OJ

is

patients and may cause instability. (Rigllt) sagitlal STIR MR shows extensive erosion of odontoid process and large SOfllissue mass II] from rheurnalOid arthritis. RA may mimic

infection

or

tumor.

Osteomyelitis,

C1-C2 (Left) Sagittal T2WI MR shows epidural abscess compressing spinal cord. (Right) Sagittal T2WI MR shows wbercular osteomyelitis involving C2 body with extension into pre vertebral space E!:J. Posterior elements are also involved Sparing of disc space is characteristic of tubercular osteomyelitis early in its course.

=

=.

Meningioma (Left) Sagittal bone CT shows calcified mass with dural tail arising from ventral dura at C2 providing clue to dural origin. There is mass effect on adjacent spinal cord. (Rigllt) Sagittal T2WI Fs MR shows multiple small foci of abnormal signal intensity in bone marrow of C·spine,

=

=

clivus, and occiput.

Note

posterior element involvement, which is a common MR finding with myeloma.

II 2 7

c

CVJ SOFT TISSUE ABNORMALITY

:go c

-,:::> ro ~

.0 Q)

t Q)

>

.Q

c

~

U Ql

c .0. tJ)

DIFFERENTIAL DIAGNOSIS Common • Rheumatoid Arthritis • Retro-Odontoid Pseudotumor • Osteomyelitis, CI-C2 • Extramedullary Tumor o Metastases o Lymphoma o Plasmacytoma o Nasopharyngeal Carcinoma o Neurofibromatosis Type 1 o Schwannoma o Paraganglioma o Chordoma o Chondrosarcoma o Meningioma • Intramedullary Mass o Syringomyelia o Chiari 1 Malformation o Chiari 2 Malformation o Glioma, Brainstem o Hemangioblastoma, Spinal Cord Less Common • Carotid Pseudoaneurysm/Dissection • Synovial Cyst Rare but Important • Neurenteric Cyst

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Do intralesion calcifications represent arc-whorl intralesional calcifications (chondrosarcoma) or fragmented destroyed bone (chordoma, metastasis)? • Does patient have known primary neoplasm (metastasis), myeloma (plasmacytoma), or a nasopharyngeal mass (nasopharyngeal carcinoma)?

II 2 8

Helpful Clues for Common Diagnoses • Rheumatoid Arthritis o Thickened & inflamed synovium called pannus o ever involves spine without hands &/or feet involvement o Odontoid erosions, ligamentous laxity o CI-C2 instability in 33% of all RA patients o Neutral, flexion, and extension lateral radiographs performed for evaluation

• High correlation to neurologic symptoms with distance 9 mm or more between Cl-2 • Retro-Odontoid Pseudotumor o Increased soft tissue dorsal to odontoid secondary to Cl-2 osteoarthritis • Low signal mass on T1 & T2 (fibrotic) • May cause cervicomedullary junction compression o Usually seen with altered biomechanics of lower cervical spine •• surgical/congenital fusion o Mimics appearance of RA o Multiple other levels of degenerative disc disease • Osteomyelitis, CI-C2 o Infection starts as septic arthritis of Cl-2 o Risk factors include diabetes, drug abuse, endocarditis, immunocompromise o Soft tissue mass and bone destruction at Cl-2 level • Staph aureus most common organism in USA • Mycobacterium tuberculosis most common worldwide o MR shows low Tl signal mass centered at Cl-2 with variable involvement of odontoid and lateral masses at C2 o May show enlarged atlanto-dental interval o Epidural mass with thecal sac/cord corn pression o Grisel syndrome: Inflammatory, nontraumatic subluxation of CI-C2 following peripharyngeal infection • Extramedullary Tumor o Metastases • Multiple lesions, bone destruction, systemic primary o Lymphoma • Large pharyngeal mucosal space mass with associated cervical adenopathy> 50% of time • NHL 5x as common as Hodgkin disease in head & neck o Nasopharyngeal Carcinoma • Mass centered in lateral pharyngeal recess of NP with deep extension & cervical adenopathy • Nodal metastases present in 90% of cases at presentation

CVJ SOFT TISSUE ABNORMALITY • Multi-planar images show invasion of clivus, sphenoid bone & sinus, Cl & C2 bodies o Neurofibromatosis Type 1 • Plexiform neurofibroma => diffuse enlargement of major nerve trunks/branches - bulky rope-like ("bag of worms") nerve expansion with adjacent tissue distortion • Look for kyphoscoliosis ± multiple nerve root tumors, plexiform neurofibroma, dural ectasia/lateral meningocele o Schwannoma • Hypoglossal or upper cervical roots as site of origin • Hypoglossal neuropathy results in tongue denervation • Dumbbell with uniform enhancement • Larger lesions may show central cystic formation o Paraganglioma • Multiple black dots ("pepper") in tumor substance indicating high velocity flow voids from feeding arterial branches • Jugular foramen or vagal varieties may present with upper cervical/skull base level mass o Chordoma • Mass is hyperintense to discs on T2WI, with multiple septa • Destructive, lytic lesion • May extend into disc, involve 2 or more ad jacen t vertebrae o Chondrosarcoma

Rheumatoid Arthritis

• Lytic mass with or without chondroid matrix, cortical disruption, and extension into soft tissues • Chondroid matrix mineralization of "rings and arcs" (characteristic) o Meningioma • Foramen magnum, jugular foramen OF), upper cervical dura locations • Carotid space => connection to JF above with JF margins showing permeative-sclerotic or hyperostotic changes on bone CT • Absence of high-velocity flow voids on T1 MR • Tl C+ MR shows enhancing, JF mass Helpful Clues for Less Common Diagnoses • Aneurysm/Vertebral Dissection o Multiple etiologies => dissection, post-traumatic, atherosclerotic, iatrogenic, congenital • Synovial Cyst o Round, central T2 hyperintense mass with low signal margin o Associated with dorsal Cl-2 articulation or degenerated facets Helpful Clues for Rare Diagnoses • Neurenteric Cyst o Intraspinal cyst + vertebral abnormalities (persistent canal of Kovalevsky, segmentation and fusion anomalies)

Retro-Odontoid Pseudotumor

II Sagittal T1WI MR shows rheumatoid arthritis involving

C1·C2 articulation with dens erosion and extensive

=.

pannus (ormation There is mild compression of medulla by pannus and obscuraUon of fat planes.

Sagittal T1WI MR shows CI-C2 degenerative pseudopannus in patient with DISH. The odontoid is not eroded, but tile ADI is t. Cord compression occurs between degenerative pannus & posterior C 1.

=

2 9

c

CVJ SOFT TISSUE ABNORMALITY

o

nc -,::J t1l .0

~ Ql

Osteomyelitis,

t

Ql

> .Q c t1l

~

U Ql

C

a.

r/)

Cl-C2

Metastases

(Left) Sagiltal T2WI MR show large pre vertebral abscess spanning Cl to C4 lID and extension posteriorfy involving interspinous region 81. Findings are typical for T8. (Right) Axial Tl C+ FS MR shows melaslatic lung cancer with extensive extracapsular nodal spread.

Post-contrast image shows Ihe mass has ill-defined borders with invasion of the longus capitis muscle !'::1l and invasion to the pharyngeal mucosal space 81.

Metastases

Lymphoma

(Left) Axial CTA shows Ihe classic appearance of thyroid metastasis with thin

expansiJe bony margin with the predominalely

lytic

lesion within left

facel/lamina of C3 ~. (Right) Axial CECT shows homogeneous mass in the relropharyngeal space, displacing Ihe parapharyngeal fal anterolaterally 81 and encircling the right internal carotid artery

Plasmacytoma (Left) Sagiltal Tl C+ MR shows variant MR case an unusually large skull base plasmacytoma engulfing the clivus and extending into the nasopharynx and abutting Cl-C2. (Right) Sagiltal TlWI MR shows a typical case of an aggressive nasopharyngeal squamous cell carcinoma with invasion of Ihe skull base by direct extension H2.

or

=

II 2 10

Nasopharyngeal

Carcinoma

en "2.

CVJ SOFT TISSUE ABNORMALITY

::::l CD

o ~ III

::::l

Neurofibromatosis

Chordoma

Type 1

(Left) Axial TI C+ MR shows multiple

large neurofibromas

within dorsal 50ft tissues and

paravertebral regions. Symmetrical

=

farge intradural

lesions compress the cervical cord at the C2 level. (Right) Sagillal TI C+ MR demonstrates an isointens€ expansile mass arising from the cfivus~. Notice the posterior indentation or "thumbing"

0· < CD ::I. CD

r:::r

~ III L. C

::::l

$:l0· ::::l

of the pons.

Chordoma (Left) Sagillal T 1 C+ MR shows large heterogeneous signal mass in the cervical epidural space, involving rhe dorsal aspect of C2- 3 junction and extending larerally, with diffuse enhancement. (Rig"') Coronal TI WI MR shows typical MR case of petro·occipital

fissure skull

base chondrosarcoma

Carotid

=.

Pseudoaneurysm/Dissection (Left) Sagillal T1 C+ MR shows well-defined and

homogeneously

enhancing

mass with a broad dural margin

Ea at

the foramen

magnum, typical for meningioma.

There is

compression of the medulla. (Right) Axial CTA shows the CT features of a pseudoaneurysm of rhe internal carotid artery locared below the skull base.

=

II 2 11

c

Cl-C2

o

nc

-,:J CO

~

.c Q) t Q)

> .Q c CO

~

U OJ

c:

'Q. CJ)

INSTABILITY

Common • Trauma o Jefferson Cl Fracture o Odontoid C2 Fracture o Hyperflexion Injury, Cervical o Rotary Subluxation, Atlantoaxial o Os Odontoideum o Pathologic Vertebral Fracture • Non-Traumatic o Rheumatoid Arthritis, Adult o Spondyloarthropathy, Seronegative Less Common • Non-Traumatic o CPPD o Osteomyelitis, CI-C2 o Grisel Syndrome o Achondroplasia o Trisomy 21 (10-20%, 1-2% Symptomatic) o Spondyloepiphyseal Dysplasia o Mucopolysaccharidoses (MPS) • Mimics of Instability o Normal Variant o Incomplete Fusion, Posterior Element o CraniovertebraJ Junction Variants o Calcific Tendinitis, Longus Coli o Pseudosubluxation (Childhood)

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Imaging Evaluation of Instability

Transverse ligament of dens critical to anteroposterior stability o Normal distance from inferior margin Cl arch to dens < 2 mm in adults o Increased distance indicates rupture transverse ligament • Flexion-extension views useful • May be false negative in 1st week after injury o Jefferson fracture unstable if combined lateral displacement of Cllateral masses relative to articular pillars of C2 " 7 mm Incomplete fusion of posterior elements does not cause instability because ligaments intact Grisel syndrome in association with retropharyngeal infection, primarily seen in children Rheumatoid arthritis often also involves atlanto-axial articulations, lower cervical uncovertebral and facet joints o Will not be present in C-spine unless peripheral involvement also present o RA pannus does not calcify Calcified inflammatory tissue around dens usually due to CPPD o

DIFFERENTIAL DIAGNOSIS

•

•

•

•

Other Essential Information • Craniocervical junction injuries often multilevel • Os odontoideum felt to represent nonunited dens fracture

Jefferson C1 Fracture

Odontoid C2 Fracture

II 2

=

Axial bone CT shows lateral dislocation of C1

relative

lateral displacement

12

instability.

to C2 arUcular pillars

of lateral masses>

of lateral masses . Combined

7 mm confirms

Sagittal

NECT shows

type

/I odontoid

fracture

=.

unstable injury seen primarily in elderly paUents, after a trivial injury such as a ground level fall.

an

often

Cl-C2

en

INSTABILITY

-C ::::s (1)

Os

Odontoideum

Rheumatoid

Arthritis,

Adult (Lefl) Sagillal bone CT shows nonuniled

dens fracture

=..

called as odontoideum. These are commonly unstable and should be evaluated with flexion/extension views. (RighI) Sagillal NECT shows widening of CI-2 interval SI due to rupture of transverse ligament of dens caused by

pannus. Note bony erosion ofdens=.

CPPD fLeft) Sagillal bone CT shows calciFications around dens ~ in this patient presenting with instability. CPPO crystals were seen on biopsy at time of surgical fusion. (RighI) Sagillal T2WI MR shows MRSA infection involving

occiput

=

to C2.

Prevertebral abscess

and

abscess surrounding dens =:7& narrowing evident.

Craniovertebral

spinal canal are

Junction Variants (Left) Sagillal N[CT shows C2-] pseudosubluxation = in a child. Posterior laminar line from C1 to C] is normal. C2-] anterolisthesis of < 4 mm is seen as a normal variant in up to 40% of children. fRighl) Anteroposterior radiograph shows failure of fusion of posterior arch C 7 8l mimicking fracture. Unlike (racture, rnargins of defect are smooth

and corlicaled.

II 2

c

ODONTOID

o

DEFORMITY

13 c

--,::J

co ~

.0

OJ

t

OJ

> .Q

c co ~

U Q)

c a.

en

DIFFERENTIAL DIAGNOSIS

CPPD Rarely, gout • Hypoplasia: Odontoid short and body of C2 dysmorphic o o

Common • Trauma o Odontoid C2 Fracture o Os Odontoideum • Arthritis o Rheumatoid Arthritis, Adult o CPPD o Seronegative Spondyloarthropathy o Juvenile Idiopathic Arthritis • Tumor o Metastases, Lytic Osseous o Multiple Myeloma • Craniovertebral Junction Variants Less Common • Congenital o Spondyloepiphyseal Dysplasia o Hypoplastic Odontoid Process o Klippel-Feil Spectrum o Down Syndrome o Mucopolysaccharidoses • Tumor o Osteochondroma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Erosion vs. hypoplasia vs. trauma • Erosion of odontoid: Odontoid may have pencil tip or erosion at base • Soft tissue mass around odontoid o Infection o Rheumatoid arthritis Odontoid

Helpful Clues for Common Diagnoses • Acute Trauma: Odontoid may be displaced or angled posteriorly on lateral view o Often difficult to see fracture on odontoid view, especially in osteopenic patients • Chronic Post-Traumatic Deformity o Os Odontoideum: Rounded ossicle o Angular Deformity: Tip of odontoid points posteriorly • Bone Tumor: Marrow abnormality visible on CT or MR; lytic lesions difficult to see on radiographs due to overlying structures • Rheumatoid Arthritis (RA): Pannus never calcifies; arthritis always present in hands or feet if seen in neck • Seronegative Spondyloarthropathy o Syndesmophytes fuse multiple vertebrae; erosions of odontoid may look same as RA • CPPD: Soft tissue mass contains calcification • Infection: Usually unifocal; often epidural extension • Congenital Deformity: Odontoid abnormal in shape but cortex intact; other anomalies often present

C2 Fracture

II 2 14

=

I.2teral radiograph shows posterior displacement of the odontoid relative to the body of C2, indicating an odontoid fracture.

Sagittal STIR MR shows a sofl tissue mass around U,e dens and bony erosion of the dens 81.

=

ODONTOID

DEFORMITY

o ~ OJ

:J

Juvenile Idiopathic

a

Arthritis

<

(Left) Sagiltal bone CT shows chronic separation of C 1 and C2 and a tapered contour of the odontoid.

Heterotopic

ossification 1::1 has developed between the odontoid and C1. (Right) Sagittal STIR MR shows a treated myeloma lesion =:I of C2, with partial collapse of the odontoid into the vertebral body.

Craniovertebral

C1l

::+ C1l

CT OJ

~

'C

:J

~

o· :J

Junction Variants (Left) Sagittal bone CT shows a normal physeal scar

-=

between

the ossification

centers for the dens and for

the C2 vertebral body. Lucency around the physeal scar is also normal. (Right) Lateral radiograph shows a tapered, small odontoid process =:I secondary to the congenital fusion of occiput andCl.

Down Syndrome (Left) Sagittal bone CT shows congenital fusion of C2 and C3 leading to a tower-like appearance of the odontoid process PJ:'J. (Right) Sagiltal bone CT shows an unusually shaped odontoid without erosions and the widening of the Cl-2 interval in this patient with symptomatic instability related to trisomy 21.

II 2 15

SECTION 3 Vertebral Body - Posterior Elements Anatomically Based Differentials Congenital Vertebral Anomalies Cervical Bony Fusion

11-3-2 11-3-4

Generic Imaging Patterns Flattened Vertebral Body, Solitary Flattened Vertebral Body, Multiple Dysmorphic Vertebral Body Enlarged Vertebral Body/Posterior Element Enlarged Neural Foramen Vertebral Body Scalloping/Widened Canal Spondylolisthesis Bony Lesion, Aggressive Fracture, Vertebral Body Facet Abnormality, Non-traumatic Fracture, Posterior Element Pedicle Abnormality

Modality-Specific Enlarged Vertebral Vertebral Vertebral Vertebral Vertebral Vertebral Vertebral

11-3-6 11-3-8 11-3-10 11-3-12 11-3-16 11-3-18 11-3-20 11-3-24 11-3-28 11-3-32 11-3-34 11-3-36

Imaging Findings

Vertebral Body, Soap Bubble Expansion Body Sclerosis, Focal Body Sclerosis, Diffuse Body Thickened Bony Trabeculae Body, T1 Hyperintense Signal, Diffuse Body, T1 Hyperintense Signal, Focal Body, T1 Hypointense Signal, Diffuse Body, T1 Hypointense Signal, Focal

11-3-38 11-3-42 11-3-44 11-3-46 11-3-48 11-3-50 11-3-52 11-3-56

CONGENITAL

l/)

c

VERTEBRAL ANOMALIES

Q)

E Q) W ~ o

'C Q)

eno

CL

>o

'0

CO

~
.0 Q)

1:: Q)

> Q)

c: c..

DIFFERENTIAL DIAGNOSIS

o o

Common • Abnormalities of Segmentation o Failure of Vertebral Formation o Vertebral Segmentation Failure o Partial Vertebral Duplication o Klippel-Feil Spectrum o Craniovertebral Junction Variants o VACTERL Association o Scoliosis and Kyphosis, Congenital • Acquired Vertebral Body Fusion

en

o

DISH

• •

•

less Common • Multiple Abnormally Formed Vertebrae without Fusion, Congenital o Achondroplasia o Osteogenesis Imperfecta o Thanatophoric Dwarfism o Spondyloepiphyseal Dysplasia o Mucopolysaccharidoses

ESSENTIAL INFORMATION

Juvenile Idiopathic Arthritis o Spondyloarthropathy, Seronegative o Post-Operative Change, Normal Spinal Dysraphism o Incomplete Fusion, Posterior Element o Meningocele, Dorsal Spinal o Myelomeningocele o Lipomyelomeningocele o Diastematomyelia Caudal Regression Syndrome Multiple Abnormally Shaped Vertebrae, Acquired o Scheuermann Disease o Sickle Cell o Juvenile Idiopathic Arthritis o Cushing Disease o Osteomyelitis, Granulomatous o Radiation of Spine in Childhood Single Abnormally Shaped Vertebra, Acquired o Limbus Vertebra o

•

Post-Traumatic Deformity Osteochondroma

Partial Vertebral

Key Differential Diagnosis Issues • Must decide if single or multiple levels involved • Abnormalities acquired in childhood cause growth disturbance, mimic congenital anomalies • Extra-spinal abnormalities often helpful in diagnosis Helpful Clues for Common Diagnoses • Abnormalities of segmentation may not be visible on routine radiographs o Coned-down views, CT scan, or MR useful especially at craniocervical junction o Always consider, especially with atypical scoliosis • Short curve, unbalanced, or thoracic convex left • Widened spinal canal on AP radiograph sign of dysraphism

Klippel-Feil Spectrum

Duplication

II

3 2

Coronal bone CT shows left hemivertebra

=

associated rib. It causes a shorl-curve scoliosis.

lacking an

=

radiograph shows a failure of segmentation of C2-C3 involving both vertebral bodies and facet joints. There is wide variability in extent of fusion in Klippel-Feil spectrum. Lilteral

CONGENITAL

Juvenile Idiopathic

VERTEBRAL ANOMALIES

Arthritis (Left) Lateral radiograph shows small fused vertebral bodies 81 and facet joints in the lower cervical spine, indistinguishable from congenital Fusion. A wide Cl-2 interval is a clue to diagnosis. (RighI) Sagittal bone CT shows ossification of the anterior longitudinal ligament that clearly is beyond the margins of the vertebral bodies, distinguishing this entity from fusion anomalies.

=

=

Post-Operative

Change, Normal

m CD

3

CD

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en

Diastematomyelia (Left) Sagillal CECT shows Facet joint Fusion Although current fusion techniques usually employ hardware, older techniques may not and may be confused with congenital fusion. (Right) Axial T2WI MR shows a bone spur dividing the spinal canal and a split spinal cord 81.

=.

=

limbus Vertebra

Osteochondroma (Left) Sagillal NECT shows a failure of fusion of ring apophysis E3I that occurs in

adolescence due to extension of disc material between the apophysis and the remainder

of the

vertebral body. (Right) Axial bone CT shows an osteochondroma mimicking a bony septum in the spinal canal. These benign tumors rarely involve the spine and are not present at birth.

=

II 3 3

CERVICAL BONY FUSION

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DIFFERENTIAL DIAGNOSIS Common • Abnormalities of Segmentation o Failure of Vertebral Formation o Partial Vertebral Duplication o Klippel-Feil Spectrum o Vertebral Segmentation Failure • Juvenile Idiopathic Arthritis • DISH • Post-Traumatic Deformity • Spondyloarthropathy, Seronegative • OPLL • Post-Operative Change, Normal Less Common • Osteomyelitis, Pyogenic • Osteomyelitis, Granulomatous

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Fusion occurring congenitally or in childhood o Vertebral bodies small in anteroposterior dimension relative to adjacent segments o Juvenile idiopathic arthritis: Associated with arthritis elsewhere • May see cervical instability • Involves vertebral bodies and facet joints o Congenital fusion: May be isolated abnormality or multiple levels • May involve vertebral body, facet joints or both • Known as Klippel-Feil spectrum Vertebral

II 3 4

Segmentation

Failure

Lateral radiograph shows fusion =:I of the anterior and posterior columns of C2 and C3. Note that the vertebral bodies arc narrow in AP dimension, a sign of congenital or childhood fusion.

• May be associated with Sprengel deformity • Often see scoliosis or kyphosis • Fusion due to seronegative spondyloarthropathy o Normal size of vertebral bodies o Intervertebral discs and facet joints fused o Sacroiliac joints always involved with erosions often progressing to ankylosis o Thin syndesmophytes in ankylosing spondylitis cause "bamboo spine" appearance o Flowing ossification along paraspinous ligaments seen in psoriatic and reactive arthritis • Fusion due to DISH o Flowing ossification along paraspinous ligaments o Patients usually older than SO years o Sacroiliac joints usually normal but rarely appear fused due to enthesophytes • Surgical fusion o Older surgeries often without hardware Helpful Clues for Less Common Diagnoses • Fusion due to osteomyelitis o Rare in cervical spine o Vertebral body fusion usually does not affect facet joints o Loss of vertebral body height, loss of definition of endplates o Single level in pyogenic, often multiple in granulomatous o Often develop kyphosis

Juvenile Idiopathic

Arthritis

Lateral radiograph shows fusion of the C7-T2 vertebrae 9. The narrow AP dimension reflects a growth disturbance from childhood fusion. The widened c/-2 1:1] distance is a clue to }IA.

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CERVICAL BONY FUSION

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Juvenile Idiopathic

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Arthritis (Left) Sagillal bone CT shows an unusual fusion between the anterior arch of the C 7 and dens PJ:ill in a patient with juvenile idiopathic arthritis and c/-2 subluxation. (Right) Sagillal T1 WI MR shows bulky anterior ossification confluent over 4 vertebral bodies. Ossification of this

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magniwde may cause

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dysphagia.

Spondyloarthropathy,

Q)

Seronegative (Left) Lateral radiograph shows thin syndesmophytes PJ:ill along the vertebral bodies and fusion of facet joints (Right) Lateral radiograph shows bulky ossification of the posterior longitudinal ligament Patient has less extensive ossification of the anterior longitudinalligamenl.

=.

=.

Post-Operative

Change, Normal (Left) Lateral radiograph shows anterior intervertebral fusion performed without hardware. The normal size of the vertebral bodies distinguishes this from congenital or childhood fusion. A lack of deformity distinguishes this from fusion due to infection. (Right) Sagittal T2WI MR shows osteomyelitis at C6-7 Osteomyelitis not infrequently leads to vertebral fusion.

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=.

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FLATTENED VERTEBRAL BODY, SOLITARY

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DIFFERENTIAL DIAGNOSIS Common • Pathologic Vertebral Fracture o Osteoporosis o Metastases, Lytic Osseous o Metastases, Blastic Osseous o Plasmacytoma o Multiple Myeloma o Steroids o Langerhans Cell Histiocytosis o Giant Cell Tumor o Ewing Sarcoma o Leukemia o Lymphoma o Osteomyelitis, Pyogenic o Hemangioma • Burst Fracture • Chance Fracture • Failure of Vertebral Formation less Common • Ki.immell Disease

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Single vertebra plana should always raise suspicion for underlying lytic lesion Helpful Clues for Common Diagnoses • Radiographic findings suggesting that a vertebra plana is due to tumor o Normal bone density in remainder of spine

II 3 6

Cortical destruction: Vertebral body or neural arch o "Absent pedicle" sign o Lytic or blastic lesion seen in other vertebrae • MR appearance often allows differentiation between vertebra plana due to osteoporosis and tumor a Osteoporosis: Band-like or stellate abnormal signal, focal cortical break but no widespread cortical destruction o Tumor: Cortical destruction, round or ovoid marrow replacement, marrow replacing entire vertebral body or involving neural arch • Langerhans cell histiocytosis most likely cause in young patients • Congenital vertebral anomalies cause well-demarcated hypoplasia o

Helpful Clues for less Common Diagnoses • Ki.immell Disease a Gas in flattened vertebral body Other Essential Information • Paraspinous soft tissue mass not a helpful differen tial diagnostic finding o May be due to hematoma in non pathologic fracture, to paraspinous tumor, or to paraspinous abscess

Osteoporosis

Osteoporosis

Sagittal bone CT shows flattened, sclerotic T6 \'ertebra with callus formation, in elderly paUent. Mild T7 compression fracture is a/50 present

Sagittal Tl WI MR shows fracture line at LJ surrounded by band of low signal intensity, characteristic of acute fracture edema/hemorrhage. allow-up confirmed osteoporotic burst fracture.

81 due to subacute burst fracture,

=

=

r

flATTENED

VERTEBRAL BODY, SOLITARY

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CT OJ

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Langerhans Cell Histiocytosis (Left) Sagittal T7WI MR shows pathologic L3 burst fracture with complete vertebral marrow

by

replacement cortical

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tumof,

destruction,

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and

exlraosseous extension

(Right) Lateral radiograph shows vertebra plana in a 9 year old boy. Ewing

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sarcoma may have the same

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appearance

on imaging.

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Burst Fracture (Left) Sagittal T2WI MR shows 2 vertebral bodies and intervening

disc space

involved with tumor, but only C6 shows flattening Involvement of vertebrae with osteomyelitis lends to be nonunifo,m. (Right) Sagittal T7WI MR shows

=.

traumatic

burst fracture,

retropulsion

with

of posterior

vertebral body cortex 81. Note hemangioma ~ at the level above the fractu,e.

Failure of Vertebral

Formation

Ki.immell Disease (Left) Coronal bone CT shows that the left side of L3 is markedly hypoplastic a congenital anomaly that may be isolated or associated with VACT£RL syndrome. (Right) Coronal bone CT shows flattened vertebral body containing gas pathognomonic for

=-

Kiimmefl

disease. Cas has

migrated from the disc space into the nonunited

fracture

with secondary

osteonecrosis.

II 3 7

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DIFFERENTIAL DIAGNOSIS Common • Traumatic Fractures • Pathologic Vertebral Fracture o Osteoporosis o Metastases, Lytic Osseous o Multiple Myeloma o Metastases, Blastic Osseous o Leukemia o Lymphoma • Sickle Cell • Scheuermann Kyphosis less Common • Osteogenesis Tmperfecta • Achondroplasia • Cushing Disease • Spondyloepiphyseal Dysplasia • Caudal Regression Syndrome Rare but Important • Radiation Therapy to Spine in Childhood

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Traumatic spine fractures often occur at multiple contiguous or noncontiguous levels even in young patients • MR useful to look for marrow replacement disorder in patients with multiple fractures • Metastases o Radiographs: Cortical breakthrough, loss of pedicle

Traumatic

II 3 8

Fractures

Sagittal STIR MR shows mulliple compression

~ due patient.

10

oCT: Destruction of trabeculae o MR: Rounded lesions underlying fractures, often elsewhere in spine as well • Myeloma, lymphoma, leukemia o Similar to metastases, but loss of pedicle uncommonly seen on radiographs o MR, CT show posterior element involvement is common o Lytic lesions in spine often difficult to see on radiographs • Most common appearance is diffuse osteopenia, fractures o Focal, round areas of marrow replacement or diffuse marrow replacement may be seen • Sickle cell: Vertebral height lost centrally only ("Lincoln Log vertebrae") • Scheuermann kyphosis o 5° wedging of at least 4 contiguous vertebrae o Schmorl nodes & undulating vertebral endplates o Usually involves thoracic spine Helpful Clues for less Common Diagnoses • Osteogenesis Imperfecta o Severe osteopenia, thin bone cortices o Multiple fractures varying in severity, including pancake vertebrae o Scoliosis often present • Cushing Disease o Pronounced concavity of end plate ("fish mouth vertebrae")

Osteoporosis

fraclUres

molar vehicle accident in a 30 year old

LLlteraJ radiograph shows multiple compression fractures ~ due 10 osteoporosis. CT or MR is useful in these patients to exclude marrow replacement by tumor.

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VERTEBRAL BODY, MULTIPLE

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Blastic Osseous (Left) Sagittal bone CT shows mulliple flallened verlebrae There is a moth-eaten appearance lhroughoullhe verlebral bodies due 10 myeloma and a single large lytic lesion E2. (Right) Coronal bone CT shows 1055 of heighl of mulliple verlebral bodies E2 due 10 blaslic metastases. Allhough the bone is increased in density, it is not structurally sound, and patients are at increased fracture risk.

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(Left) Coronal NECT shows diffuse bony sclerosis and vertebrae with variable degrees of flallening. Cenlral verlebral flaltening with preserved margins

=

resembles

lOy

"Lincoln

Logs". (Right) Sagiltal T2WI MR shows flaltening and wedge deformities of 5 adjacent vertebrae

=.

Involvement

of at

least 4

vertebrae with at least 50 wedging of each verlebra, undulating appearance of endplales, and definable Schmor! nodes indicate Scheuermann kyphosis.

Osteogenesis

Imperfecta (Left) Anleroposterior radiograph shows severe osteoporosis. Variable degrees of vertebral flaltening refleCl fraclure, of varying severity. (Right) Coronal bone CT shows mild verlebral flaltening and undulating vertebral endplates.

II 3 9

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DYSMORPHIC VERTEBRAL BODY

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DIFFERENTIAL DIAGNOSIS Common • Single Vertebral Body o Post-Traumatic Deformity o Schmorl ode o Limbus Vertebra o Metastases, Lytic Osseous • Multiple but not all Vertebral Bodies o Abnormal Segmentation • Partial Vertebral Duplication • Vertebral Segmentation Failure • Klippel-Feil Spectrum o Scheuermann Disease o Scoliosis o Metastases, Lytic Osseous o Juvenile Idiopathic Arthritis o Neurogenic (Charcot) Arthropathy o Post-Radiation Changes • Diffusely Abnormal Vertebral Bodies o Sickle Cell o Osteogenesis Imperfecta o Achondroplasia less Common • Single Vertebral Body o Klimmell Disease o Osteochondroma o Ewing Sarcoma o Langerhans Cell Histiocytosis • Multiple Vertebral Bodies o Osteomyelitis, Pyogenic o Osteomyelitis, Granulomatous • Diffusely Abnormal Vertebral Bodies o Thanatophoric Dwarfism Schmorl Node

II 3

Lateral fluoroscopy shows extending into Schmorl node

discographic contrast Schmorl nodes are

=:I.

caused by disc intravasation into vertebrallxx1y.

10

o

Mucopolysaccharidoses

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Single vertebrae with abnormal appearance usually post-traumatic • 2 or more adjacent vertebrae with abnormal appearance usually segmentation anomaly Helpful Clues for Common Diagnoses • Scheuermann disease causes undulating appearance of vertebral endplates • Cushing disease causes cupping deformity of vertebral endplates • Infection and neurogenic arthropathy are centered on intervertebral disc and show endplate erosions • Juvenile idiopathic arthritis results in vertebral bodies that are tall relative to anteroposterior diameter • Klimmell disease distinguished by gas in vertebral body • Sickle cell causes "Lincoln Log" deformity • Mucopolysaccharidoses and achondroplasia cause "bullet vertebrae" with anterior portion of body small • Vertebral bodies near apex of a scoliosis often mildly misshapen • Tumors involving only part of vertebral body may cause a dysmorphic appearance due to partial collapse

Limbus Vertebra

Sagittal bone CT shows well-marginated ossicle

=:I at

anterior corner of vertebral body. Limbus vertebra is due to disc herniating between vertebral body & ring apophysis, preventing normal fusion.

DYSMORPHIC

Vertebral

Segmentation

Failure

VERTEBRAL BODY

Scheuermann

Disease (Left) Lateral radiograph shows congenital fusion of occiput and C1 Ell with resultant abnormal motion causing a dysmorphic appearance of C2 ~. C4 and CS are flatter than normal,

without

definite

fusion anomaly. (RighI) Sagiual bone CT shows mild anterior wedging and irregular vertebral endplales due to multiple Schmorf nodes characteristic of Scheuermann kyphosis.

a

Sickle Cell

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(Left) Laleral radiograph shows fused vertebrae with narrow

AP diameter

due to growlh failure. Erosion of dens ~ is a clue to Ihe diagnosis. (Right) Sagiual T2WI MR shows /I Lincoln Log'I appearance 81 of almosl alf the included vertebrae, with preserved peripheral body height and central flattening reflecting bone infarcts.

Osteochondroma

Osteomyelitis,

Granulomatous (Left) Coronal bone CT shows an osteochondroma of C2 causing deformity of both the C2 and C 1. Osteochondromas of the

=

spine are very rare, even in

patienls with multiple hereditary exostoses. (Right) Sagittal bone CT shows multiple, fused, misshapen verlebrae and kyphosis due to tuberculosis.

II 3 11

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DIFFERENTIAL DIAGNOSIS Common • Facet Arthropathy o Facet Arthropathy, Cervical o Facet Arthropathy, Lumbar o Baastrup Sign • Paget Disease • Aggressive Hemangioma • Compensatory Enlargement o Scoliosis o Spondylolysis • Congenital Fusion Less Common • Metastases, Lytic Osseous • Aneurysmal Bone Cyst • Osteoblastoma • Chordoma Rare but Important • Fibrous Dysplasia • Chondrosarcoma • Osteochondroma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Osteoblastoma should always be considered in the differential diagnosis of painful scoliosis • Center of the lesion in the vertebral body vs. posterior element may help with the differential diagnosis

II 3 12

Helpful Clues for Common Diagnoses • Facet Arthropathy, Cervical o Capsular laxity and joint space narrowing may lead to degenerative spondylolisthesis o Osteoarthritis of synovial-lined zygapophyseal joints o Hypertrophic changes with osteophytes, normal bone mineralization, & joint space narrowing • Facet Arthropathy, Lumbar o Osseous hypertrophy with articular joint space narrowing and encroachment upon neural foramen o Irritation of synovium produces synovial hyperplasia with paradoxical joint space widening o Facet arthrosis syndrome with low back, hip, and buttock pain aggravated by rest

• Baastrup Sign o Close approx. & contact of adjacent spinous process with reactive sclerosis, enlargement & flattening of apposing interspinous surfaces o "Kissing" spinous processes o Cystic degeneration of interspinous ligaments and posterocentral epidural cyst • Paget Disease o Enlarged vertebra and neural arch with diffusely coarsened & haphazard bony trabecular pattern • Most commonly L3 & L4 • Cortex is thickened • Anterior concavity of the vertebral body is lost o Can cause spinal stenosis & neural forami nal narrowing o 0 epidural soft tissue component unless sarcomatous degeneration • Aggressive Hemangioma o Expanded & indistinct cortex, irregular honeycombing pattern, & soft tissue mass • Trabecular condensation thinner in comparison to Paget disease o Lesions commonly involve entire vertebral body with extension into neural arch o Typically occur between T3 & T9 o Epidural extension may cause cord compression o Can become symptomatic with growth, which often occurs during pregnancy • Compensatory Enlargement o Scoliosis • Minimal structural vertebral deformities & advanced degenerative changes • Facet osseous overgrowth, asymmetric disc space, & discogenic sclerosis at the concave aspect of the scoliosis • Unilateral radicular symptoms on the side of the concavity of the deformity o Spondylolysis • Defects in pars interarticularis (PI) may be due to repetitive stress injury • Spinal canal is elongated at the level of the pars defect on axial imaging • Most common at LS • Sclerosis of PI, volume averaging of superior facet spur, partial facetectomy, blastic metastases may mimic spondylolysis

ENLARGED

VERTEBRAL BODY/POSTERIOR

• Congenital Fusion a Vertebral bodies smaller than normal with tapered contour at fused disc space a Rudimentary disc space with reduced height & diameter, "wasp waist" a Degenerative changes at adjacent levels a ± Fusion of posterior elements Helpful Clues for less Common Diagnoses • Metastases, Lytic Osseous a 50-70% bone destruction required for detection on radiography a Lesion involves posterior cortex & pedicle a Diffuse involvement of marrow gives the appearance of brighter disc than bone on TlWI a Fat suppression on enhanced Tl WI helpful to unmask lesions • Aneurysmal Bone Cyst a Arise in the neural arch with the majority (75-90%) extending into the vertebral body a Expansile remodeling of bone with cortical thinning a Fluid-fluid levels with hemorrhage a No tumor matrix • Osteoblastoma a Originate in the neural arch, often extend into the vertebral body 0> 1.5 cm (osteoid osteoma < 1.5 cm) a Narrow zone of transition with sclerotic rim a Bone matrix on CT or radiograph

ElEMENT

May be associated with an aneurysmal bone cyst (10-15%) a Painful scoliosis (50-60%) • Chordoma a Rare involvement of the vertebral body a Purely lytic a T2 hyperintense with multiple septations a Variable enhancement a Amorphous intratumoral Ca++ in 30% of vertebral lesions a

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Helpful Clues for Rare Diagnoses • Fibrous Dysplasia a Neural arch involvement> vertebral body a Spine involvement in polyostotic disease a Mildly expansile lesion with characteristic ground-glass matrix a Heterogeneous Tl & T2 signal and enhancement • Chondrosarcoma a Lytic, destructive lesion with cortical destruction and extension into the soft tissues a ± Chondroid matrix (50%) of "rings & arcs" • Osteochondroma a Sessile or pedunculated osseous lesion contiguous with the parent vertebra a Cartilaginous cap> 1.5 cm in adults concerning for malignant transformation

Facet Arthropathy

Axial

bone

overgrowth stenosis.

CT shows severe left unilateral

ffi

facet

causing moderately severe central

=

Sagittal T7WI MR shows degeneration changes of lhe interspinous ligament and ligamentous flavum WiU1 a poslerior epidural cySI!:;].

II 3

ENLARGED VERTEBRAL BODY/POSTERIOR

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C

ELEMENT

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Paget Disease (Left) Sagittal STIR MR shows a mildly enlarged L2 vertebral body in the AP dimension with relatively low signal. Enlargement & brighter signal in the spinous process 81 reflect more fibrovascular tissue. (Right) Sagittal T2WI MR shows a T2 hyperintense mass involving a thoracic vertebral body & posterior elements, with a large amount of epidural extension & cord compression A typical hyperintense hemangioma is seen the level above 81.

=

=

=.

=

Scoliosis

Spondylolysis

fLeft) Axial T2WI MR shows (acet osteoarthritis asymmetric disc space narrowing, &. discogenic sclerosis E2 at the concave aspect of the scoliosis. Disc bulges can be far lateral & are better seen on the axial views. (Right) IIxial CECT shows myelogram of chronic isthmic spondylolysis 1:1 resulting in the "wide canal" sign. There is increased AP diameler of bony canal at L5 relative to more the cephalad levels.

Congenital Fusion (Left) Sagittal bone CT shows fusion of L I, L2, & L3 vertebral bodies. Smaller fused vertebrae are characteristic of congenital

=

fusion. Advanced

degenerative disc disease below the kyphoscoliosis results in spinal & neural foraminal stenosis ~. (Rig"') Sagittal STIR MR shows an enlarged hyperintense upper thoracic vertebral body lesion and a smaller lesion in the body below A heterogeneous enlarged thyroid mass is also

=.

II 3 14

seen

81.

Metastases,

Lytic Osseous

ENLARGED VERTEBRAL BODY/POSTERIOR

ElEMENT

<

CD

Aneurysmal Bone Cyst

;::+ CD rr ~

Osteoblastoma (Left) Axial NECT shows a large bony expansile mass that involves the entire posterior element ~ and body 1:1] of C2. {/uid-(fuid levels are characteristic. There may be minimal enhancement (Right) Axial T2WI MR shows a

heterogeneous

III

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o

0-

'<

mass

expanding the right lamina E1. Scoliosis is concave on the side of the tumor. The

mass enhanced heterogeneously on T1 C+ scan (not shown).

Chordoma (Left) Sagittal T1 C+ MR shows diffuse marrow

replacement 811 with enhancing epidural mass

1:1]

and severe cord compression !:ll. T2 hyperintensity &, heterogeneous enhancement are typical for vertebral chordoma. (Right) Axial NECT shows focal expansion of the lamina and spinous

process 811 with areas of cyst formation &, ill-defined calcific matrix

Chondrosarcoma

=.

Osteochondroma (Left) Sagittal T2WI MR shows a large enhancing soft tissue mass with verlebral body !:ll and posterior elementlC7J involvement &, cord compression. (Right) Coronal T2WI MR shows a heterogeneous extradural mass 811 with a thin T2

rs

hyperintense cartilaginous cap that compresses the spinal cord against the ventrolateral spinal eana/. The spinal cord is deviated anteriorly and to the left but there's no abnormal spinal cord signal.

= II 3 15

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ENLARGED

C

NEURAL

FORAMEN

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Common • Nerve Sheath Tumor o Schwannoma o Neurofibroma • Perineural Root Sleeve Cysts • Dural Dysplasia • Lytic Metastasis to Vertebral Body or Pedicle Less Common • Osteomyelitis, Granulomatous • Neuroblastic Tumor • Post-Traumatic Pseudomeningocele • Meningocele, Lateral • Vertebral Artery Ectasia or Aneurysm • Osteolytic Primary Bone Tumor o Aneurysmal Bone Cyst o Plasmacytoma Rare but Important • Hypoplastic or Absent Pedicle

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • CT useful to distinguish bony remodeling (benign or low grade mass) from osteolysis (aggressive neoplasm, infection) Helpful Clues for Common Diagnoses • Nerve Sheath Tumor o Transforaminal "dumbbell-shaped" enhancing soft tissue mass • Perineural Root Sleeve Cysts

Schwannoma

II 3 16

Circumscribed foraminal masses, often multiple, tend to be small (1-3 cm) o Contents follow CSF, no enhancement, ± opacification with myelography • Dural Dysplasia o Transmission of chronic CSF pressures by weakened dura leads to bony remodeling and expansion of lumbosacral canal and neuroforamina o Can be seen with neurofibromatosis type I, Marfan disease, homocystinuria, Ehlers-Danlos, and ankylosing spondylitis • Lytic Metastasis to Vertebral Body or Pedicle o Destructive process with loss of cortex, wider zone of transition to normal bone, multiple osseous lesions o Renal, lung, and breast are common primaries to develop osteolytic metastases o

DIFFERENTIAL DIAGNOSIS

Helpful Clues for Less Common Diagnoses • Osteomyelitis, Granulomatous o Tuberculosis may present with osteolytic lesion of the neural arch o Also: Brucellosis, coccidioidomycosis, blastomycosis, actinomycosis • Neuroblastic Tumor o Paravertebral mass ± transforaminal and epidural extension o Foraminal enlargement by remodeling or bony destruction • Post-Traumatic Pseudomeningocele o Cystic transforaminal structure, neural elements usually absent

Neurofibroma

=

with remodeled, well-corlicaled margin and severely thinned pedicle in this patient with a large

Axial T1 C+ MR shows an oblong, enhancing soft tissue mass extending through and enlarging the left C4-S neural foramen The intraspinal component causes

lfansforamina/schwannoma.

severe cord compression ~.

Sagillal NECT shows an enlarged neural foramen

=_

ENLARGED

Perineural

Root Sleeve Cysts

NEURAL FORAMEN

Dural Dysplasia (Left) Axial T2WI MR shows thin-walled cystic foraminal masses larger on the left, remodeling the thoracic neural foramina bilaterally. (Rigllt) Lateral radiograph shows posterior vertebral scalloping and enlargement

=

of multiple

neuroforamina

=:11 due

to dural dysplasia in this patient with neurofibromatosis type I.

m

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3 CD

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lytic Metastasis to Vertebral Pedicle

Body or Neuroblastic

Tumor (Left) Axial NECT shows destructive renal cell metastasis destroying posterolateral thoracic vertebral body, resulting in widening of the bony margins

of the neural

foramen =:11. (Right) Sagillal T1WI MR shows transforaminal

invasion of

the epidural space in this patient with a paraspinal neuroblastoma. There is remodeling and enlargement of the left T12-L 1 neural foramen with abnormal soft tissue also in adjacent neuroForamina.

=

Post-Traumatic

Pseudomeningocele

Meningocele,

lateral (Left) Axial T1 WI MR shows the cyst-like fluid collection extending through, and chronically enlarging, the neural (oramen at the site

-==

of

a

remote

nerve root

avulsion. (Right) Axial NECT shows large soft tissue density with smooth margin extending through an enlarged

foramen

=

left thoracic

neural

and filling the

left hemithorax

in this patient

with type 1 neurofibromatosis.

II 3 17

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less Common • Congenital Skeletal Disorders o Achondroplasia o Mucopolysaccharidoses (Morquio, Hurler) • Diastematomyelia • Juvenile Idiopathic Arthritis • Severe, Longstanding Communicating Hydrocephalus • Hydrosyringomyelia • Acromegaly

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • ormal Variant o Body slightly concave on all surfaces • Vertebral Segmentation Failure o Single level cervical fusion a rather common, incidental anomaly Vertebral Segmentation

"Waisted" appearance at the fusion due to stress shielding Dural Dysplasia o Intrinsic weakness in dura, transmitted CSF pressure causes bony remodeling o Seen with neurofibromatosis type 1, Marfan disease, homocystinuria, Ehlers-Danlos, and ankylosing spondylitis Ependymoma o Enhancing intramedullary or in trad ural-extramed ullary (lurn bosacral canal) mass Schwannonla o Extramedullary mass, typically ventral or lateral to the cord or within fibers of the cauda equina o Those associated with canal remodeling typically fusiform or dumbbell in shape Neurofibroma o In this context, not reliably differentiated from schwannoma (see above) Meningioma o Intradural-extramedullary enhancing mass, with broad dural base Arachnoid Cyst o Circumscribed, thin-walled, nonenhancing extramedullary mass, follows CSF signal/attenuation o

DIFFERENTIAL DIAGNOSIS Common • Normal Variant • Vertebral Segmentation Failure • Dural Dysplasia • Intraspinal Mass o Ependymoma o Schwannoma o Neurofibroma o Meningioma o Arachnoid Cyst o Lipoma o Astrocytoma o Dermoid and Epidermoid Tumors

CANAL

•

•

•

•

•

•

Helpful Clues for less Common Diagnoses • Achondroplasia o Congenitally short, narrowed pedicles; bullet-shaped vertebral bodies with posterior scalloping

Failure

Dural Dysplasia

II 3

Sagittal bone CT shows developmental fusion of C3 and C4 with "waisting" allhe level of the fusion ~

Lateral radiograph demonstrates posterior scalloping of multiple vertebral bodies and enlargement of

=

multiple

18

neural foramina

neurofibromatosis.

~

in thi5 patient

with type 7

VERTEBRAL BODY SCALLOPING/WIDENED

Ul

CANAL

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Schwannoma (Left) Sagiltal Tl C+ MR shows a large lobulated enhancing mass tilling the distal thecal sac and expanding & remodeling the lumbosacral canal (Right) Sagittal Tl C+ MR shows unusually extensive,

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Cyst

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Achondroplasia (Left) Sagittal T2WI MR shows a large lobulated extradural mass, tollowing CSF signal, widening the spinal canal by remodeling the dorsal elements and compressing the spinal cord. (Right) Lateral radiograph

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shows shortened pedicles and posterior scalloping

Diastematomyelia

Juvenile Idiopathic

vertebral

Arthritis (Left) Axial T2' GRE MR shows dysmorphic vertebral body with enlarged cervical canal and a split spinal cord ~> (Right) Lateral radiograph shows tusion at multiple abnormally slender cervical vertebral bodies with a widened

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canal

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II 3 19

SPONDYlOLISTHESIS

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DIFFERENTIAL DIAGNOSIS Common • Pediatric Pseudosubluxation • Dysplastic • Degenerative Disc Disease • Spondylolysis • Post-Treatment Instability • Posterior Column Injury, Cervical Less Common • Osteomyelitis, Pyogenic • Tuberculous Infection • Tumor o Metastasis o Lymphoma o Multiple Myeloma o Primary Bone Tumor • Osteosarcoma • Osteoblastoma • Chondrosarcoma • Rheumatoid Arthritis, Adult

ESSENTIAL INFORMATION

II 3 20

Key Differential Diagnosis Issues • Spondylolisthesis ~ displacement of one vertebral body relative to another o Dysplastic (congenital abnormality of arch) o Isthmic (fatigue or stress fractures of pars) o Degenerative (osteoarthritic segmental instability of facets) o Traumatic o Pathologic (local bone disease) • Most common is isthmic and degenerative • Spondylolisthesis can occur with or without spondylolysis • Spondylolisthesis graded by amount of anterior displacement of superior body by 25% stages o < 25% ~ grade 1, < 50 ~ grade 2, < 75% grade 3, < 100% ~ grade 4, > 100% ~ spondyloptosis • Anterior displacement of vertebral body ~ "uncovering" of the posterior disc margin with pseudobulge deformity • Look for focal herniations in addition to the pseudobulge at the level of spondylolisthesis and at adjacent levels where stress is increased

• Spondylolysis ~ break in pars interarticularis of vertebrae leaving two parts o Anterior component of vertebral body, pedicle, superior facet o Posterior component of inferior facet, lamina, spinous process Helpful Clues for Common Diagnoses • Pediatric Pseudosubluxation o Normal mobility C2 on C3 in flexion o Seen in 40% of children at C2-3, 14% of children at C3-4 level o Only seen with flexion o May be mistaken for ligamentous injury, since 70% of cervical spine fractures in children occur from Cl to C3 o C2 displaced up to 3-4 mm o Age < 14 years o Swischuk line: Drawn from anterior aspect of CI-C3 spinous processes ~ normal within 1 mm of anterior C2 spinous process o If in doubt on plain film or CT, then MR to exclude ligamentous injury • Degenerative Disc Disease o Most common at L4-5 o Wide canal sign not present since no defects in pars o Usually grade 1 without lysis o Look for severely degenerated facets + disc degeneration o Lose of height of neural foramen with stenosis as superior body slips forward o Posterior retrolisthesis ~ disc degeneration with disc height loss, rostrocaudal subluxation of facets • Spondylolysis 090% at L5-S1, bulk of remainder at L4-5 • L3 and above unusual ~ question gymnastics o 20% may have unilateral defect in pars o May show contralateral compensatory bone hypertrophy and sclerosis • Not to be mistaken for osteoid osteoma! o Wide canal sign present (increase in AP diameter of bony canal at lysis level relative to normal levels) with bilateral lysis • Post-Treatment Instability o Deformity that increases with motion and increases over time o Dynamic slip> 3 mm in flexion/extension

SPON DYLOLISTH ESIS Static slip of 4.5 mm or greater Angulation> 10-15° suggests need for surgical intervention o Stabilizing anatomic structures • Anterior longitudinal ligament (resists hyperextension) • Posterior longitudinal ligament • Intertransverse ligaments (connect neighboring transverse processes) • Interspinous ligaments (resists hyperflexion) • Facet capsule • Ligamentum flavum • Intervertebral disc: Main stabilizer of lumbar and thoracic spine • Muscular attachments • Posterior Column Injury, Cervical o Fractures of laminae, facets, or spinous processes o Disruption of ligaments bridging spinous processes + laminae o If capsular ligaments torn, facets, &/or laminae both fractured, rotational instability may exist o Flexion extension films or fluoroscopy to assess degree of instability o o

Helpful Clues for Less Common Diagnoses • Tuberculous Infection o Endplate irregularity and bone destruction o T2 hyperintense disc, vertebral bodies o Look for associated epidural phlegmon/ abscess

Pediatric

Fat-suppressed post-contrast Tl images useful for epidural disease and paravertebral/psoas extension • Tumor o Destruction of posterior elements + vertebral body leads to secondary instability • Rheumatoid Arthritis, Adult o Subaxial anterior + posterior subluxations common o Atlantoaxial subluxation in 5% of patients with cervical rheumatoid arthritis o Instability may also be present at lower levels of cervical spine o Spine radiographs in flexion/extension to assess for instability o Look for Cl-2 involvement with retrodental pannus + subaxial spondylolisthesis o

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SELECTED REFERENCES 1.

2.

3. 4. 5.

Nizard RS et al: Radiologic assessment of lumbar intervertebral instability and degenerative spondylolisthesis. Radiol Clin North Am. 39(1):55-71, v-vi, 2001 Brady WJ et al: ED use of flexion-extension cervical spine radiography in the evaluation of blunt trauma. Am J Emerg Med. 17(6):504-8, 1999 Frymoyer JW et al: Segmental instability. Rationale for treatment. Spine. 10(3):280-6, 1985 Swischuk LE: Anterior displacement of C2 in children: physiologic or pathologic. Radiology. 122(3):759-63, 1977 Cattell HS et al: Pseudosubluxation and other normal variations in the cervical spine in children.

J

Bone Joint

Surg Am. 47(7):1295-309,1965

Pseudosubluxation

=-

Sagittal NECT shows slight subluxation at C2-3 which is within normal variation. Posterior laminar fine from Cl to C3 is normal. Normal anterior displacement orC2 on C3 is up to 4 mm.

Sagittal TI WI MR shows dysplastic spondylolisthesis in a repaired myelomeningocele patient with Chiari 2. Small and trapezoid-shaped LS body in contrast to the more normal-sized L4.

=-

II 3 21

SPONDYLOLISTHESIS

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Dysplastic (Left) Sagiltal CECT shows dysplastic form of spondylolisthesis with slight anterior subluxation L5 on 51 =:I in this 72 year old. (Right) Sagittal CECT shows absent pars at L5-S 7 level SlI in this case of dysplastic form of spondylolisthesis. Contrast to normal pars and inFerior facet at L4.

1Il

Degenerative

Disc Disease

(Left) Sagiltal T 1 WI MR shows multilevel severe degenerative disc disease with spondylolisthesis at L4-5 =:I and retrolisthesis at L2-] SlI. There is marked loss of disc space height at multiple levels. (Right) Sagittal NECT shows spondylolisthesis and spondylolysis at L5-S7 with a well-defined corticated break ~ There is moderate Foraminal stenosis at L5-51.

Spondylolysis (Left) Sagittal bone CT shows severe spondylolytic spondylolisthesis with the posterior margin L5 vertebral body =:I at the same position as the anterior margin S 7 SlI. II pars defect is readily apparent with premature large osteophytes and foraminal narrowing. (Right) Lateral radiograph in flexion shows grade 2 anterolislhesis that improved on extension related to wide multilevel

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laminectomies.

II 3 22

Post- Treatment Instability

SPONDYLOLISTHESIS

Post-Treatment

Instability

Posterior Column

Injury, Cervical (Left) Sagiltal T1 WI MR shows post-operative spondylolisthesis following a lumbar laminectomy L4 & 5 E1. Acute compression fracture is present at L 1. (Right) Coronal NECT shows comminuted fracture of posterior elements at C7 c::l.

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(Left) Sagiltal T2WI MR shows flexion rotation injury of the cervical spine with a Facet fracture,

vertebral

subluxation =::I, and cord edema. There is widening of the posterior elements at C6-781. (Right) Sagiltal T2WI MR shows bilateral facet subluxation and C5-6 subluxation following trauma, with cord hemorrhage 81 and ALL disruption ~.

Tumor (Left) Sagittal N£CT shows destruction of L5 and SI centered at the intervertebral disc level, with anterolisthesis of L5 on 5 I due to loss of disc stability from disc space infection.

(Right) Sagiltal T1 WI MR shows pars defect at L5-SI E::II in this patient with extensive bony metastatic disease. Multiple pathologic nodes are present lID.

II 3 23

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DIFFERENTIAL DIAGNOSIS Common • Metastases, Lytic Osseous • Metastases, Blastic Osseous • Lymphoma • Multiple Myeloma • Osteomyelitis, Pyogenic • Osteomyelitis, Granulomatous less Common • Degenerative Endplate Changes • Accelerated Degeneration • Schmorl Node • Langerhans Cell Histiocytosis Rare but Important • Spondyloarthropathy, Hemodialysis • Neurogenic (Charcot) Arthropathy

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Bone destruction (tumor, infection) vs. remodeling, short transition zone (degenerative disc disease)

II 3 24

Helpful Clues for Common Diagnoses • Metastases, Lytic Osseous o Lytic, permeative diffusely enhancing lesion destroys posterior cortex & pedicle o Tl hypointense/T2 hypo ~ hyperintense, T2 hyperintense rim surrounding hypointense met • Metastases, Blastic Osseous o Sclerotic lesion destroys posterior cortex & pedicle o Tl/T2 hypointense with variable enhancement depending on degree of sclerosis • Lymphoma o Lytic, permeative bone destruction may cross disc spaces o Tl hypointense, T2 iso-/hyperintense, & diffuse uniform enhancement o ± Soft tissue mass • Multiple Myeloma o Multifocallytic lesions with cortical disruption & extraosseous soft tissue component • Pedicle involvement is late o Compression fractures with variable canal narrowing

• 67% appear benign • Osteomyelitis, Pyogenic o III-defined Tl hypointensity in vertebral marrow with loss of adjacent end plate delineation o T2/STIR hyperintense marrow o Endplate osteolytic/osteosclerotic changes on CT & vertebral collapse o Disc space narrowing & enhancement o ± Paraspinal/epidural infiltrative soft tissue with loculated fluid (75%) • Osteomyelitis, Granulomatous o Tuberculous spondylitis shows vertebral collapse & large paraspinal abscess (± calcification) • ± Destruction of disc • Isolated posterior element involvement o Brucellar spondylitis shows anterosuperior epiphysitis (L4) with associated sacroiliitis • Intervertebral disc destruction & relatively intact vertebrae o Multiple (non)contiguous vertebrae with endplate irregularity & osteolysis o Enhancement of epidural soft tissue mass, marrow, disc, dura, subligamentous soft tissues o Chronically shows fusion across disc space Helpful Clues for less Common Diagnoses • Degenerative EndpIate Changes o Loss of disc space height, loss of horizontal nuclear cleft on T2WI, linear disc enhancement • No bone destruction • Vacuum phenomenon (low Tl/T2 signal) o Type 1: Tl hypo-!T2 hyperintense, may show prominent enhancement • Inflammatory in orgin, but association with lower back pain controversial • Associate with segmental instability with good clinical outcome following fusion o Type 2: Tl/T2 hyperintense o Type 3: Tl/T2 hypo intense, sclerosis on CT & radiographs • Accelerated Degeneration o Degenerative changes of disc space/facets at levels adjacent to surgical fusion & congenital segmentation anomalies • Most common finding at adjacent segment is disc degeneration • No bone destruction o Response to altered biomechanical stresses

BONY LESION, AGGRESSIVE

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Intradiscal pressure, t facet loading, & t mobility occur after fusion implicated in causing adjacent segment disease • Rate of symptomatic adjacent segment disease t with transpedicular instrumentation (12.2-18.5%) • Fusion with other forms of instrumentation or with no instrumentation (5.2-5.6%) • Risk factors: Instrumentation, fusion length, sagittal malalignment, facet injury, age, & pre-existing degenerative changes • Schmorl Node o Focal invagination of vertebral endplate by disc material • Low Tl/high T2 signal in adjacent marrow if acute • Diffuse marrow enhancement if acute, marginal enhancement if subacute • Most commonly seen at the T8 through Lllevels & always contiguous with parent disc • t

Helpful Clues for Rare Diagnoses • Spondyloarthropathy, Hemodialysis o Erosions of anterior corners of vertebral body & erosions & cysts of adjacent endplates with minimal osteophyte formation o Severe narrowing of disc space o ± Soft tissue mass o Crystal (visible calcification) & amyloid deposition

Low Tl signal, low to intermediate T2/STIR signal o Progression to vertebral body collapse or listhesis with spinal instability & cord compression o Imaging simulates an infectious process with destruction & irregular enhancement of the endplates & narrowing of disc space o Disease correlates with duration of hemodialysis, although can be seen with only chronic renal insufficiency • Neurogenic (Charcot) Arthropathy o Destruction of discs, end plates, & facet joints with preserved bone density o Bone debris around vertebrae & fluid collections, which do not enhance as avidly as abscess o Diffuse enhancement involving discs & facet joints o Most often in lumbar spine, sometimes in lower thoracic spine • Involves 1-2 spinal levels o Can be rapidly progressive destroying a joint in a month o Etiologies include diabetes mellitus, neurosyphilis, status post-traumatic paraplegia o

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Axial NECT shows a renal cell metastasis destroying the right side of a thoracic vertebral body. right posterior elements. & right costovertebral joint The ventral margin shows bony expansion.

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II 3 25

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BONY LESION, AGGRESSIVE

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lymphoma (Left) Sagittal T1WI MR shows a soft tissue mass replacing L5 vertebra with exlraosseous extension ~ & pathologic compression fracture. (Right) Axial T1 C+ MR shows marrow replacement & heterogeneous enhancement throughoullhe vertebral body, extending into the right neural arch Ell. There is extension of tumor into the anterior paraspinous soft tissues ~ & epidural space. The epidural extent of the lUmor results in the "draped curtain 1/ sign

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Osteomyelitis, (Left) Sagittal T1 WI MR reveals mullifocal geographic areas of abnormal signal Majority of the lesions are lower signal intensity than the intervertebral discs, a sign that these represent tumor rather than

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heterogeneous

marrow.

(Right) Sagittal STIR MR shows C5·6 disc space infection with disc irregularity & increased signal in contiguous bodies. A small epidural abscess ~ mildly effaces the cord. There is extensive prevertebral edema

=.

Osteomyelitis, (Left) Sagittal T2Wf FS MR shows complete collapse of the L2 body Ell. Adjacent intervertebral discs are contiguous. A focal abscess ~ protrudes posteriorly with compression of the thecal sac. (Right) Sagittal STIR MR shows bone marrow edema adjacent to endplates multiple bulging discs, & narrowing of intervertebral discs. This pallern is characteristic of edema secondary either to instability or to loss of cushioning effect of the intervertebral discs.

=-

II 3 26

Granulomatous

Pyogenic

BONY LESION, AGGRESSIVE

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severe degenerative changes al T1UI, U-2, & L2-] EB (Right) Sagillal T1 C+ fS MR shows a bone bruise at level 01 Schmorlnode. The band-like region of marrow enhancement m surrounding the Schmorl node ~ is consistent with acute injury.

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(Left) Coronal N[CT shows amyloid/crystal deposition disease in patient

with fang

term renal failure. There are multiple areas bone erosion centered about synovial joints with mild bony expansion. (Right) Coronal bone CT shows extensive bony debris in the

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II 3 27

C/)

FRACTURE,VERTEBRALBODY

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DIFFERENTIAL DIAGNOSIS Common • Vertebral Body Only a Anterior Compression Fracture, Thoracic a Anterior Compression Fracture, Lumbar a Lateral Compression Fracture, Lumbar a Lateral Compression Fracture, Thoracic a Burst Fracture (Mild) a Pathologic Vertebral Fracture a Hyperflexion Injury, Cervical a Hyperextension Injury, Cervical • Vertebral Body Plus Posterior Elements a Burst Thoracolumbar Fracture a Burst Fracture, Lumbar a Burst Fracture, Cervical a Pathologic Vertebral Fracture a Burst Fracture, C2 a Hyperflexion Injury, Cervical a Hyperextension Injury, Cervical a Chance Fracture, Thoracic a Distraction Fx, Low Thoracic • Fracture Mimics a Schmorl Node a Limbus Vertebra a Kyphosis, Idiopathic a Scheuermann Disease a Sickle Cell a Scoliosis and Kyphosis, Congenital a Neurogenic (Charcot) Arthropathy a Osteomyelitis, Pyogenic Less Common • Lymphoma • Cushing Disease • Ki.immell Disease • Osteomyelitis, Granulomatous • Congenital Syndromes a Failure of Vertebral Formation a Osteogenesis Imperfecta a Diastematomyelia a Achondroplasia, Mucopolysaccharidoses a Mucopolysaccharidoses Rare but Important • Ewing Sarcoma • Apophyseal Ring Fracture

ESSENTIAL INFORMATION

II 3 28

Key Differential Diagnosis Issues • Mechanism of injury a Compression, burst: Axial load injuries

Chance: Anterior compression, posterior distraction a Fracture/dislocation: Shear forces • Treatment of different types of fractures is different, so imaging distinction is important • Imaging may overestimate or underestimate mechanical instability of spine • Fracture vs. fracture mimic a History of trauma may not be available or reliable a Fractures may be single or multiple levels a May have different kinds of fractures at different levels • e.g., burst and compression at 2 different levels a Multiple, uniformly involved levels of deformity usually not traumatic a

Helpful Clues for Common Diagnoses • Compression Fracture a Does not involve posterior vertebral body cortex or posterior elements a Common throughout thoracic and lumbar spine a May involve anterior or lateral portion of vertebral body a Often occur at multiple levels in normal or osteoporotic bone a Most common type of pathologic fracture • Burst Fracture a Burst fracture extends through posterior cortex of vertebral body a More severe burst fractures show vertically oriented fractures of neural arch a Most common at thoracolumbar junction • Chance Fracture a Anterior compression vertebral body a In conjunction with horizontally oriented fracture of posterior elements OR ligamentous injury resulting in separation of adjacent spinous processes a Most common at thoracolumbar junction • Hybrid Fractures a Some fractures have elements of both burst- and chance-type injury • Retropulsion of posterior vertebral body cortex + separation of posterior elements • Best to categorize as Chance and add description of burst elements • Compression or Burst Fracture due to Trauma or Osteoporosis

FRACTURE, VERTEBRAL BODY

MR: Band-like configuration of abnormal signal a CT: Trabeculae compressed but not destroyed • Compression or Burst Fracture due to Tumor a Radiographic findings • Focal osteopenia or osteosclerosis • Cortical destruction • Nonvisualization of pedicle contour on AP radiograph a helpful sign a MR findings • Rounded configuration of abnormal signal, or diffuse abnormal signal adjacent to fracture • Cortical breakthrough beyond fracture line is often seen • Additional areas of abnormal signal without fracture helpful signs when present a CT findings • Destruction of trabeculae adjacent to fracture • Cortical break beyond fracture line is often seen • Additional areas of bony destruction without fracture helpful signs when present • Limbus Vertebra a Ossicle anterior corner of vertebral body, smoothly contoured & corticated a Failure of fusion of ring apophysis • Kyphosis, Idiopathic a

Anterior Compression Fracture, Lumbar

Smooth vertebral endplate contour, multiple vertebrae a Diagnosis of exclusion • Scheuermann Disease a Undulating contour of endplates a Discrete Schmorl nodes variably present a 4 or more contiguous vertebral bodies with at least S° wedging each • Sickle Cell a H-shaped or "Lincoln Log" vertebrae with central depression and preserved margins • Infection or Neuropathic Arthropathy a Endplate destroyed, irregular a

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Helpful Clues for Less Common Diagnoses • Kiimmell Disease a Gas in vertebral body cleft; flattened vertebral body • Osteomyelitis, Granulomatous a Multiple vertebral fusions, kyphosis • Congenital Vertebral Anomalies a Smoothly marginated, usually involve multiple vertebral bodies • Osteogenesis Imperfecta a Severe osteopenia, scoliosis, multiple fractures of varying severity • Achondroplasia, Mucopolysaccharidoses a Bullet-shaped vertebrae

Burst Thoracolumbar Fracture

SI in this young palient with normal bone density

Lateral radiograph shows burst fracture in a young patient, with retropulsion of posterior vertebral body

Palient has chronic spondylolysis of L4.

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II 3 29

FRACTURE, VERTEBRAL BODY

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Marrow

is

diffusely abnormal signal intensity. (Rigl1t) Lateral radiograph shows wedge deformity and "flexion teardrop" fragment at CS. Widened interspinous distance ~ and laminar

1::1

fracture m are evidence of posterior distraction Force.

(Left) Sagittal NECT shows characteristic pattern of cervical injury in DISH. Hyperextension fracture ~ extends through ossified ALL and vertebral body. In ankylosing spondylitis, fracture usually extends through disc and spares vertebral body. (Right) Sagiltal STIR MR shows

anterior vertebral

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compression and tear of interspinous ligaments E2 indicating

flexion-distraction

(Chance) fracture.

Chance Fracture, Thoracic (Left) Sagiltal bone CT shows flexion-distraction

injury,

with anterior compression E1 and posterior distraction fractures. There is also retropulsion r=::l of the posterior cortex of the vertebral body (Lypical of

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the

preponderant patlern is that of a Chance fracture. (Right) Sagiltal NECT shows fracture-dislocation at T4-S Ell. Cord was lransected.

II 3 30

FRACTURE, VERTEBRAL BODY

Schmorl Node

Kyphosis, Idiopathic (Left) Sagittal bone CT shows a typical Schmorf node a bowl-shaped depression in the vertebral endplate due to disc material herniating through endplate. (Right) Lateral radiograph shows marked kyphosis of the upper thoracic spine and multilevel degenerative disc disease m. There are no congenital abnormalities, fractures, Scheuermann

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(Left) Anteroposterior radiograph shows "butterfly

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cleft in vertebra can be mistaken for fracture. (Right) Sagittal bone CT shows fracture !l:J through vertebral body and posterior arch after spinal fusion in this paraplegic patient. Neurogenic arthropathy features fractures lhallend nOlla heal, with resultant abnormal motion and bony destruction.

(Left) Sagittal bone CT shows bony destruction at L1 and L2 SlI due to osteomyelitis, causing kyphosis and hardware failure. (Right) Sagittal bone CT shows gas-filled cleft in vertebral posHraumatic avascular necrosis Kiimmell disease.

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II 3 31

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FACET ABNORMALITY,

NON-TRAUMATIC

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DIFFERENTIAL DIAGNOSIS Common • Normal Variant o Facet Tropism • Facet Arthropathy o Facet Synovial Cyst • Tumor Destruction o Metastases, Lytic Osseous o Lymphoma o Multiple Myeloma Less Common • Rheumatoid Arthritis, Adult • Congenital Fusion • Septic Facet Joint Arthritis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Assess vertebral abnormalities, multiplicity (i.e., metastases), & soft tissue component (i.e., RA pannus, epidural abscess) Helpful Clues for Common Diagnoses • Normal Variant o Facet Tropism • Asymmetry in orientation of zygapophyseal joint surfaces up to 35% • L5-S1 > L4-5 • Stress hypertrophy of pedicle on the more coronally oriented side • Facet Arthropathy o Osseous facet overgrowth with encroachment upon neural foramina

II 3 32

Cartilage erosion & joint space narrowing o Facet Synovial Cyst • Extradural cystic mass extending from degenerative facet joint • Internal high Tl/low T2 signal due to hemorrhage or proteinaceous content & low T2 rim 2° wall calcification • Tumor Destruction o Lytic mets: Irregular preservation of trabeculae & buttressing, isolated fronts of cortical bone resorption coalescing to confluence o Multiple myeloma: Sharply defined, spheroid lesions with smooth borders & effaced/erased trabeculae, absence of remodeling o

Helpful Clues for Less Common Diagnoses • Rheumatoid Arthritis, Adult o Inflammatory arthritis involve synovial joints (facet & uncovertebral) w/erosions o Cervical spine involvement in 60% • C1-C2 instability in 33%; atlantoaxial subluxation in 5% • Congenital Fusion o Segmen tation failure of 2 or more cervical vertebra o Vertebral body narrowing at fused rudimentary disc space o ± Fusion of facets & spinous processes • Septic Facet Joint Arthritis o T2 hyperintensity and enhancement extends into adjacent soft tissues o ± Epidural abscess/phlegmon

Facet Tropism

Facet Synovial Cyst

Axial T2WI MR shows asymmetry of the face15 and lamina 8

Axial T2WI MRshows an extradural lesion SI extending anleromedially into the spinal canal from a hypertrophic facet joint !:D. Internal mixed to proteinaceous material.

hypoinlensily

may be due

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Metastases, lytic Osseous (Left) Sagillal TI WI MR shows expansile hypoinlense lesion involving the body, pedicle, and articular pillars of a mid-thoracic vertebral body The soft tissue component extends into the epidural space. (Right) Axial CTA shows a thyroid metastasis giving thin expansile bony margin with the predominantly lytic lesion involving the vertebral body and left facet/lamina of C3 There is epidural extension with cord compression E1.

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Rheumatoid Arthritis, Adult (Left) Sagillal TI WI MR shows multiple thoracic bodies & articular pillar with abnormal/ow T J signal & a large paravertebral & epidural mass. The mass is typical for lymphoma, given the infiltrate nature of the body involvement without bone destruction & low T2 signal (not shown). (Rigl1t) Coronal bone CT shows

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erosion of the

odontoid & C2 vertebral body ~ There is erosive disease also at the C2-3 and C3-4 facet joints

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Septic Facet Joint Arthritis (Left) Sagittal bone CT shows Fusion of multiple facet joints ~ in the lumbar spine. There is also partial fusion of the intervertebral disc spaces and hypoplasia of the sacrum SlI. (Right) Axial TI C+ MR shows a large epidural abscess with thick enhancement~. Note a large psoas abscess & extension of the inFection to the right facet joint with diffuse facet bone enhancement & juxta facet soft tissue involvement a.

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II 3 33

FRACTURE, POSTERIOR ELEMENT

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DIFFERENTIAL DIAGNOSIS Common • Cervical o Hyperextension Injury, Cervical o Burst Fracture, Cervical o Hangman's C2 Fracture o Lateral Flexion Injury, Cervical o Jefferson Cl Fracture o Burst Fracture, C2 o Clay Shoveler's Fracture o Hyperflexion-Rotation Injury, Cervical o Hyperflexion Injury, Cervical • Thoracic o Chance Fracture, Thoracic o Burst Thoracolumbar Fracture o Facet-Lamina Fracture, Thoracic • Lumbar o Burst Fracture, Lumbar o Spondylolysis o Facet-Posterior Fracture, Lumbar o Transverse Process Fracture o Chance Fracture, Lumbar o Pedicle Stress Fracture • All Spinal Levels o Pathologic Vertebral Fracture Less Common • Fracture Mimics o Metastases, Lytic Osseous o Incomplete Fusion, Posterior Element o Neurogenic (Charcot) Arthropathy o Vertebral Segmentation Failure o Hypoplastic Rib, Supernumerary Rib

Hangman's

II 3 34

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues • Must distinguish between isolated posterior column injury and multicolumn injury o Isolated posterior column • Due to lateral flexion or rotation, direct blow, or hyperflexion • Clay shoveler's fracture a stable hyperflexion injury o Multiple column • Due to any injury mechanism, not necessarily unstable • Non-bony involvement of middle, anterior columns often best seen on MR Helpful Clues for Common Diagnoses • Prevertebral soft tissues of cervical spine may be normal in isolated posterior element fracture • Burst fracture: Posterior column fracture in vertical plane • Flexion-distraction fracture: Posterior column fracture in horizontal plane • Spondylolysis easily missed on axial images; use following signs o "Double facet" sign: Spondylolysis is anterior to facet joint o "Wide canal" sign: Increased AP dimension of spinal canal

C2 Fracture

Axial bone CT shows bilateral C2 pedicle fractures indicating hangman's-type fracture.

=:I

Axial bone CT shows le{l·sided (ractures of anterior It] and posterior 8lI ring of C7. This is a variant Jefferson fracture.

en

FRACTURE, POSTERIOR ELEMENT

~. :J (l)

< (l)

;:l. (1)

cr ~

Burst Fracture, Lumbar (LeFI) Axial bone CT shows L2 burst fracture.

Unlike

Chance

fracture,

posterior

element

fractures are

vertically oriented I:'] and there is retropulsion of posterior vertebral body cortex ICB (RighI) Axial bone CT shows LS spondylolysis 81 anterior 10 lacet joints I:'] (double Facet sign). AP diameter of canal is widened (wide canal sign).

OJ

OJ

o Q. '<

m CO

3 (1)

:J

Ui

Transverse Process Fracture (Lefl) Sagittal bone CT shows isola led Iracture ollhe L 1

superior articular process II] with minimal displacement. Posterior element fractures can be isolated, but a search should always be made lor other Iractures. (RighI) Coronal bone CT shows isolated leFt L4 laleral process fracture

=.

These fractures

are often associated retroperitoneal

with

and pelvic

injuries.

Chance Fracture, Lumbar

Incomplete

Fusion, Posterior Element (Lefl) Sagittal bone CT shows L 7 Chance fracture (flexion-distraction) characteristic

with

horizontal

Iracture 81 01posterior elements. Vertebral body is compressed anteriorly IJ:;J. (RighI) Anteroposterior radiograph shows lailure 01 lusion 01 LS lamina I:'] and absent spinous process. This

is a

very common

normal

variant.

II 3 35

en

PEDICLE ABNORMALITY

C ell

E ell

W

~ o

"'ell"

C;;

o

0..

~

.0

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t

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> ell

c: a. m

Common • Congenitally Short Pedicles • Stress Reaction • Trauma • Thinning/Remodeling from Intraspinal Transforaminal Mass o Schwannoma o Neurofibroma o Perineural Root Sleeve Cyst o Arachnoid Cyst o Dural Dysplasia o Meningocele, Lateral o Ependymoma • Destructive Tumor o Metastases, Lytic Osseous o Aneurysmal Bone Cyst Less Common • Sclerotic/Bone-Forming Tumor o Metastases, Blastic Osseous o Fibrous Dysplasia o Osteoid Osteoma o Osteoblastoma o Osteosarcoma • Osteomyelitis, Granulomatous • Achondroplasia • Congenitally Absent or Hypoplastic

Decreased AP dimension of spinal canal and neural foramina • Stress Reaction o Abnormal biomechanicalloading across neural arch, associated with fractures of the pars and pedicle, and degenerative facet disease o Sclerosis (CT) or T2/STIR hyperintensity (MR) ± visible pedicle or pars fracture • Thinning/Remodeling from Intraspinal or Transforaminal Mass o Implies chronic mass effect/slow growth o Cortical margin should be intact on thin-slice bone algorithm CT • Metastases o Often multiple o Thin-slice bone algorithm CT useful to differentiate bony destruction from benign bony remodeling o Purely lytic: Renal, thyroid o Purely sclerotic: Prostate, carcinoid, bladder o Mixed sclerotic &/or lytic: Lung, breast o

DIFFERENTIAL DIAGNOSIS

or

Pedicle

Helpful Clues for Less Common Diagnoses • Osteomyelitis, Granulomatous o Bony destruction o Epidural/paraspinal abscesses with irregular marginal enhancement

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Congenitally Short Pedicles o Predominately lower lumbar spine Congenitally

II 3 36

Short Pedicles

Axial NECT shows a typical case of shari lumbar pedicles resulung in congenital spina.l stenosis with Ule characteristic trefoil spinal canal cross section.

Stress Reaction

=

Sagittal STIR MR shows abnormally hyperintense signal within the left L4 pedicle in lhis 15 year old who 'aler developed a pedicle stressfracture on CT

PEDiClE

Schwannoma

ABNORMALITY

Arachnoid Cyst (Left) Lateral radiograph shows marked thinning and superior displacement of an L I pedicle!:ll associated with foraminal remodeling/enlargement ~ in this patient with lransforaminalschwannoma. (Right) Axial pos/-myelogram NECT shows thinning of lhe pedicles l:l1 due to chronic remodeling by an intraspinal arachnoid cysl EJ.

Metastases,

OJ

o

c.

'<

m CO 3 C1l

:J

en

Blastic Osseous (Left) Axial TI C+ MR shows enhancing mass in the lumbar canal scalloping lhe posterior vertebral body and markedly remodeling and thinning lhe verlebral pedicles bilalerally l:l1. (Right) Axial NECT shows blastic lID metastasis in the lefl L4 pedicle due to prostate carcinoma. Note the permeative lytic lesions in lhe ver/ebral body.

Osteomyelitis,

Granulomatous (Left) Sagillal T I WI MR

shows destructive process in L2 body eXlending into pedicle wilh abnormal hypoinlense signal and loss of superior cortex Epidural phlegmon ex/ends lhrough adjacenl neuroForamina. (Right) Bone CT (30 surface shaded display) shows congenilal absence of lhe righl L5 pedicle EJ. L5 spinous process and righl pars are fused to the L4 neural arch

=.

EB

II 3 37

en

ENLARGED

C

VERTEBRAL BODY, SOAP BUBBLE EXPANSION

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DIFFERENTIAL DIAGNOSIS Common • Metastases, Lytic Osseous o Lung Carcinoma o Thyroid Carcinoma o Renal Cell Carcinoma • Multiple Myeloma • Osteoblastoma • Giant Cell Tumor • Aneurysmal Bone Cyst Less Common • Chordoma • Chondrosarcoma Rare but Important • Fibrous Dysplasia • Telangiectatic Osteosarcoma • Enchondroma • Angiosarcoma • Cystic Angiomatosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Zone of transition is helpful to assess aggressiveness • Multiplicity of lesions, soft tissue component, & vascularity of lesions can be helpful in narrowing the differential diagnosis

II 3 38

Helpful Clues for Common Diagnoses • Metastases, Lytic Osseous o Lung, thyroid, renal, breast, oro-/nasopharyngeal carcinoma • Destructive lesion involving the posterior cortex & pedicle • Intervertebral discs are spared • Location proportionate to red marrow (lumbar> thoracic> cervical) • Multiple Myeloma o Multifocal malignant proliferation of monoclonal plasma cells leads to heterogeneous Tl marrow signal o May be expansile, but vertebral compression is more common o Vertebral body more frequently involved o Pedicle involvement later than with metastases • Osteoblastoma

Ovoid expansile mass originating in the neural arch, often extend into the vertebral body o 40% in spine • 40% cervical, 25% lumbar, 20% thoracic, 15-20% sacrum o Florid edema (corona effect) suggests an aggressive process, attributable to prostaglandin release by the tumor o Peri tumoral edema enhances avidly with gadolinium administration o Usually demonstrates more discrete bone matrix as compared to fibrous dysplasia o Bone scan demonstrates avid radionuclide uptake by the tumor • Giant Cell Tumor o Expansile, lytic lesion with narrow zone of transition o ± Cortical breakthrough o Centered in vertebral body o Margin usually not sclerotic o ± Residual bone trabeculae • Aneurysmal Bone Cyst o Expansile lesion may show cortical breakthrough o Shows a narrower zone of transition o Centered in posterior elements o Can be associated with fibrous dysplasia o

Helpful Clues for Less Common Diagnoses • Chordoma o Midline soft tissue mass with osseous destruction o T2 hyperintense mass with multiple septa o Can involve adjacent vertebral bodies by extension across disc space o Arise from notochord remnants • Chondrosarcoma o Lytic mass ± chondroid matrix, "rings & arcs" o Cortical disruption o Extension into soft tissues o Nonenhancing areas: Hyaline cartilage, cystic mucoid tissue, necrosis o Neural arch involved more frequently than vertebral body Helpful Clues for Rare Diagnoses • Fibrous Dysplasia o Well-defined, expansile, radiolucent lesion o Neural arch involved more frequently than the vertebral body

ENLARGED VERTEBRAL BODY, SOAP BUBBLE EXPANSION

Spine involvement typically in polyostotic disease o Fusiform bone expansion with "ground-glass" matrix o Heterogeneous T1/T2 signal & heterogeneous enhancement o Paraspinal soft tissue extension & vertebral collapse rare o Prevalence of scoliosis in patients with polyostotic fibrous dysplasia & spinal lesions is reported between 40% and 52% • Telangiectatic Osteosarcoma o Wide zone of transition with adjacent bone o Permeative appearance & cortical disruption o Multiple fluid-fluid levels o Soft tissue mass ± mineralization • Enchondroma o Expansile, homogeneous, slightly enhancing lesion with or without calcification • Arise either from migration of hyperplasitic immature spinal cartilage outside vertebral axis • Or from metaplasia of connective tissue in contact with the spine or annulus fibrosus o Common benign cartilaginous tumour involving the acral skeleton but extremely rare in the vertebral column (2% of cases) • Angiosarcoma o Lumbar region is most commonly affected o 33% in axial skeleton o

m

CO 3 ctl :::J

SELECTED 1.

REFERENCES

en

Leet AI et al: Fibrous dysplasia in the spine: prevalence of with scoliosis. J Bone Joint Surg Am. 86-A(3):531-7, 2004 Murphey MD et al: From the archives of the AFIP. Musculoskeletal angiomatous lesions: radiologic-pathologic correlation. Radiographies. 15(4):893-917, 1995 Kumar R et al: Expansile bone lesions of the vertebra. Radiographies. 8(4):749-69, 1988 lesions and association

2.

3.

Thyroid Carcinoma

lung Carcinoma

=

SagillalSTfR MR shows a hyperintense lesion expanding a thoracic verlebral body the articular facels & epidural space 1:2.

a

Coarse trabecular/honeycomb pattern is suggestive of a vascular tumor • Cystic Angiomatosis o Lytic, well-defined, round or oval lesions within the medullary cavity o Intact cortex & variable peripheral sclerosis o Endosteal scalloping & honeycombed or latticework appearance o Discrete circular or serpentine lytic areas within bone suggest vascular channels o No periosteal reaction o

=

Axial NECT shows a lytic lesion involving the C3 body & lefl facelliamina wilh thin expansile bony margin. A soft tissue component SI in the lefl lateral epidural space is beller seen on MR (not shown).

II 3 39

ENLARGED

(/)

c

VERTEBRAL

BODY, SOAP BUBBLE EXPANSION

Q)

E Q)

l1J

~

o

'C

Renal Cell Carcinoma

Q)

U5 o

a.. >.

-0

o

[IJ ctl ~

.0 Q)

t Q)

> Cl>

c: '0. l/l

Renal Cell Carcinoma

(Left) Sagittal T7WI MR shows a large expansife mass involving the ribs & right side of T7 & TB bodies with considerable epidural extension ~. (Rig"') Axial T7WI MR shows a large mass destroying the right aspect of a mid-thoracic vertebral body, the right posterior elements, and the right ribs & costovertebral joint. Epidural extension causes cord compression The ventral

=-

margin shows bony expansion with a "soap

bubble" pattern

=:l.

Multiple

Myeloma

Osteoblastoma

(Left) Sagittal T7 C+ FS MR shows [ocal tumor involvement with enhancement E:I with

replacement of the vertebral & posterior element marrow by tumor and slight spinous process expansion~. There is severe cord compression

at both levels. (Right) Axial bone CT shows a well-demarcated expansile lesion with a narrow

transition

&

matrix~.

zone of

ground-glass

Minimal

cortical

destruction with extension into the right lateral recess is present ~.

Osteoblastoma (Left) Sagittal T7 C+ FS MR shows extensive reactive edema in the adjacent

=

posterior elements, vertebral body, & sort tissues related to an asteoblastoma.

The

peritumoral edema enhances avidly with gadolinium administration. (Rig"') Axial CECT shows a lytic, heterogeneously

enhancing

vertebral body mass ~ posterior

with

cortical

breakthrough. Mass extends into the right pedicle =:l.

II 3 40

Giant Cell Tumor

ENLARGED VERTEBRAL BODY, SOAP BUBBLE EXPANSION

Aneurysmal Bone Cyst

Chordoma (Left) Axial T2WI MR shows mass

a multi/oculated containing

multiple

fluid-fluid levels of mixed signal intensity, ,eflecting blood products. Note nodular

enhancement

of

solid componenlS & seplae between di/ated, blood-filled

spaces. Severe canal compromise by the tumor. (Right) Axial NECT shows a destructive, lytic lesion with associated sofllissue expanding lhe occipilal condyles & skull base 81. The anterior margin has a scalloped appearance 1:':1.

Chordoma

-u

o en

ro-

=:!.

o ~ m

ro 3 <1l

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Chondrosarcoma (Left) Coronal oblique S71R MR shows a well-defined mass involving the central

aspect of the sacrum, with T2/STIR hyperintensily & patchy contrast enhancement. (Right) Sagittal T7 C+ MR shows a large, intensely

enhancing

soft tissue mass with vertebral body & posterior element involvement ~ and

cord compression. enhancement of septa results in a ring & arc pattern.

Telangiectatic Osteosarcoma (Left) Axial NECT shows {ocal expansion

of the lamina

and spinous process of L2 with areas of cyst formation & ill-defined calcific malrix. (Right) Axial T' C+ MR shows an aggressive mass ~ in the L5 vertebral body & extending into the posterior elements, spinal

1:':1

canal, paraspinous

soft

tissues. Enhancement of solid components -7 surrounds nonenhancing, low signal cystic areas m.

II 3 41

VERTEBRAL BODY SCLEROSIS, FOCAL

(/)

c Q)

E w Q)

o

.'"

Q)

1iJ o

a.. >-

"0

o

al

ro ~

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> Gl

c: 0-

m

DIFFERENTIAL DIAGNOSIS Common • Bone Island • Hemangioma • Degenerative Endplate Changes • Metastases, Blastic Osseous • Insufficiency Fracture, Pedicle • Vertebroplasty/Kyphoplasty • Compression Fracture Less Common • Chronic Osteomyelitis • Early Ankylosing Spondylitis • Osteoid Osteoma

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Bone Island a Most common cause of a focal sclerotic density a Cortical bone density with faint, spiculated border a Normal uptake on bone scan • Hemangioma a Coarse, thickened vertical trabeculations • Degenerative Endplate Changes a CT analog to type 3 marrow on MR a Should see advanced degenerative change in the adjacent disc space a Extensive end plate sclerosis: Consider chronic osteomyelitis • Metastases, Blastic Osseous

II 3 42

Multiple vertebral bodies typically involved o Sclerotic (e.g., prostate, carcinoid, medulloblastoma, neuroblastoma) or mixed sclerotic and lytic (breast, lung) • Insufficiency Fracture, Pedicle a Reactive sclerosis of portions of the neural arch associated with abnormal biomechanicalloading a Can be seen with chronic fractures of the contralateral pedicle or pars, developmentally incomplete neural arch, or advanced degenerative change • Compression Fracture a Sclerosis can be seen resulting from either trabecular impaction or from the healing response a

Helpful Clues for Less Common Diagnoses • Chronic Osteomyelitis a Advanced destructive endplate changes, paravertebral soft tissue &/or fluid a Typically more extensive involvement of the adjacent vertebral bodies than seen with degenerative end plate changes • Early Ankylosing Spondylitis a Erosions and reactive sclerosis result in square vertebral bodies and "shiny corners" • Osteoid Osteoma a Central lytic focus with surrounding (reactive) bony sclerosis a Classic history is night pain, relieved by aspirin/NSAIDs

Bone Island

Hemangioma

Axial bone CT shows dense, corticalbone density lesion =:I with characteristic appearance of a bone island, including spiculated or Ilbrush-like" margins and

Axial bone CT shows characteristic appearance of a benign vertebral hemangioma, with circumscribed border and sparse, thickened trabeculae.

absence of destructive changes.

VERTEBRAL BODY SClEROSIS, FOCAL

< CD ;:+

CD CT

~

Metastases, Blastic Osseous (Left) Coronal bone CT shows marked discogenic sclerosis at L2-3 EliJ in an asymmetric distribution due to scoliosis and lateral-lis thesis. (Right) Axial NECT shows both blastic =:I and somewhat expansile lytic prostate carcinoma metastases involving the T 12 vertebral body.

III

OJ

o a. '<

m

CD 3 CD

OJ

en

Insufficiency Fracture, Pedicle (Left) Axial NECT shows a developmentally incomplete neural arch !D. Chronic stress changes include hypertrophy/sclerosis of the left pedicle and stress fracture of the left lamina EliJ. (Right) Sagittal bone CT shows compression fracture of inferior 13 body ~ Note increased sclerosis secondary to trabecular impaction. Remote appearing compression fracture of L 1 and acute L5 compression fracture also present

=.

Osteoid Osteoma (Left) Lateral radiograph shows squared configuration of the anterior vertebral body cortices and the characteristic "shiny corner" sign ~ of early ankylosing spondylitis. fRight) Axial bone CT shows an osteoid osteoma in the neural arch [;8 that contains bone matrix and has a narrow zone of transition. Reactive sclerosis is present around the lesion.

II 3 43

en

VERTEBRAL BODY SClEROSIS,

C E

DIFFUSE

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Common • Discogenic Sclerosis • Metastases, Blastic Osseous • Chronic Discitis/Osteomyelitis • Healing Fracture • Renal Osteodystrophy • Paget Disease • Sickle Cell Disease less Common • Osteopetrosis • Osteosarcoma • Myelofibrosis

•

•

Rare but Important • Radiation • Sclerotic Myeloma • Lymphoma • Hypervitaminosis A or D • Fluorosis

•

•

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Discogenic Sclerosis o Sclerotic endplate marrow, correlates to type 3 Modic changes on MR, involving both sides of the disc space o Endplate destruction or abnormal paravertebral soft tissue should prompt consideration of chronic osteomyelitis • Metastases, Blastic Osseous

Typically involves multiple vertebral bodies o Metastases from prostate, breast, carcinoid, and urothelial primaries; in children: Neuroblastoma and medulloblastoma Chronic DiscitislOsteomyelitis o Marrow sclerosis typically associated with other findings of chronic infection • Advanced end plate destruction • Paravertebral/epidural soft tissue/phlegmon Renal Osteodystrophy o Osteopenia or osteosclerosis o May manifest with endplate sclerosis ("rugger jersey" spine) Paget Disease o Patchy or diffusely sclerotic "picture frame" vertebra due to cortical thickening o Vertebral body usually enlarged Sickle Cell Disease o Medullary sclerosis due to multiple bone infarcts o Central end plate compression deformities, causing classic "H-shaped" vertebral body o

DIFFERENTIAL DIAGNOSIS

Helpful Clues for Rare Diagnoses • Lymphoma o Diffuse vertebral sclerosis ("ivory vertebra") is a rare presentation of lymphoma in the spine

SELECTED REFERENCES 1.

Graham TS: The ivory vertebra sign. Radiology.

235(2):614-5, 2005

II 3 44

Discogenic Sclerosis

Metastases, Blastic Osseous

Sagittal NECT shows severe disc space narrowing at L5-SI with vacuum phenomenon and diffusely increased sclerosis in the adjacent marrow spaces of L5 and the first sacral segment.

Sagittal CECT (CT myelogram) shows an osteoblastic metastasis (carcinoid primary) in the 13 vertebral body with 50ft tissue extension into the ventral epidural space causing canal stenosis.

VERTEBRAL BODY SClEROSIS, DIFFUSE

(Jl "0

:J

CD

< CD ;+ CD

cr ~

Chronic Discitis/Osteomyelitis (Left) Sagittal NECT shows marked sclerosis of the L3 and L4 bodies with extensive

endplate irregularity and

III

CO

o Cl. '<

bone destruction in this with chronic sequelae of pyogenic disc space infection. (Right) Axial CECT shows sclerotic vertebral body secondary to renal osteodystrophy. Note small nonfunctioning kidneys

patient

=.

m CD

3 CD

:J

Ui

Sickle Cell Disease (Left) Lateral radiograph shows a lypical case of vertebral Paget disease with a diffusely sclerotic and slighlly enlarged L3 vertebral body 81. (Right) Coronal NECT of this patient with sickle cell anemia shows diffuse vertebral sclerosis and multiple central endplate compression deFormities.

Osteopetrosis (Left) Lateral radiograph shows diffuse sclerosis of the vertebral bodies. This

appearance mixes the features of Ilrugger jersey" and "bone in bone" presentations

of

osteopetrosis. (Right) Sagittal NECT shows diffusely sclerotic thoracic vertebra ("ivory

vertebra")

in this

patient with lymphoma.

II 3 45

<J>

VERTEBRAL BODY THICKENED

C

BONY TRABECULAE

Q)

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DIFFERENTIAL DIAGNOSIS Common • Hemangioma • Paget Disease • Osteoporosis Less Common • Fibrous Dysplasia • Plasmacytoma

Key Differential Diagnosis Issues • Vertebral expansion in Paget disease, fibrous dysplasia, plasmacytoma

Helpful Clues for Less Common Diagnoses • Fibrous Dysplasia o Ground-glass matrix in mildly expanded lesion of the neural arch> vertebral body • Plasmacytoma o Originate in the vertebral body, although involvement of the posterior elements not uncommon o Endplate fractures produce curvilinear low signal areas &/or cortical irregularities • Thickened cortical struts in expanded vertebral body, "mini brain"

Helpful Clues for Common Diagnoses • Hemangioma o Corduroy pattern of thickened trabeculae & intervening fat o Aggressive lesions are characterized by epidural extent & cord compromise o Tl/T2 hyperintense • Paget Disease o Coarsened & irregular bony trabecular pattern with cortical thickening o Heterogeneous, predominantly hypointense on T1 & hyperintense on T2 o Vertebral expansion leads to varying degrees of spinal & neural foraminal stenosis

Helpful Clues for Rare Diagnoses • Metastases, Blastic Osseous o Vertebral body, esp. posterior cortex, & pedicle are involved o Sclerotic lesions may be discrete & nodular, mottled, or diffusely increased density o Hypointense on Tl WI & T2WI o Variable enhancement depending on degree of sclerosis • Lymphoma o Bony lymphomatous involvement results from hematogenous spread (95%) o Diffuse, mottled pattern with reduced signal on Tl & T2 sequences

Q)

> Ql

c: Co

en

• Osteoporosis o Marrow heterogeneity with focal islands of red marrow & centers of fat o Focal deposits of yellow marrow, esp. in posterior elements, around central venous channels, & adjacent to endplates

Rare but Important • Metastases, Blastic Osseous • Lymphoma

ESSENTIAL INFORMATION

Hemangioma

II 3 46

Sagittal T7WI MR shows a hyperintense L4 vertebral

lesion

m without

epidural expansion.

=

Sagittal NECT shows classic honeycomb appearance of hemangioma with thickened trabecula intact cortex, & focal low attenuation between trabeculae.

=

VERTEBRAL BODY THICKENED

BONY TRABECULAE

< CD ;:l.

Paget Disease

CD 0-

Osteoporosis (Lefl) Sagiltal TI WI MR demonstrates an abnormal L2 vertebral body mildly

=-

enlarged

in AP dimension,

~ OJ OJ

o c. '<

with slight height 1055& TI shortening from increased marrow

fat. There is

enlargement & heterogeneous signal in the spinous process 8l reflecting more fibrovascular tissue content. (RighI) Sagiltal TlWI MR shows chronic L3 & TI 0 Iraclures ~ with laity marrow signal. The L2 & T I 2 Iraclures are acute with low signal superior endplates l:i1.

m

ro 3 CD

:J

Vi

(Left) Coronal bone CT shows extensive ground-glass vertebra/lesions. There is osseous expansion with mixed sclerosis, lytic, & ground-glass changes 01 the skull base, lace, spine, & calvarium in a patient with severe polyostotic librous dysplasia. (RighI) Coronal bone CT shows vertebra plana at CS secondary to plasmacytoma. There is a mixed sclerotic and lytic lesion [3>] 01 the vertebral body.

(Lell) Sagiltal TI WI MR shows multiple local hypoinlenS€ areas in the upper thoracic vertebral bodies with epidural extension & cord compression 1tJ. There is a pathologic lower thoracic Iraclure 81 with no bony retropulsion. (RighI) Sagiltal NECT shows sclerotic metastatic

lesion from

lymphoma.

II 3 47

VERTEBRAL BODY, 11 HYPERINTENSE

c'"

SIGNAL,

DIFFUSE

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DIFFERENTIAL DIAGNOSIS Common • Post-Irradiation Vertebral Marrow • Normal Variant • Heterogeneous Fatty Marrow • Osteoporosis less Common • Hemangiomas • Paget Disease

(Multiple)

Ql

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'Q.

en

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Establish whether pattern is diffusely hyperintense marrow signal or multiple foci of hyperintensity within more cellular marrow Helpful Clues for Common Diagnoses • Post-Irradiation Vertebral Marrow o Diffuse hyperintense fatty marrow signal intensity within correct clinical context o Look for abrupt sharp demarcation between hyperintense fatty marrow and lower signal intensity normal marrow at peripheral margin of radiation field • Normal Variant o Normal marrow complement of fat and cellular elements o More frequently seen in older patients • Heterogeneous Fatty Marrow o Multiple patchy areas of fat signal intensity within multiple vertebral bodies

Post-Irradiation

II 3 48

Vertebral

Marrow

o More frequently seen in older patients • Osteoporosis o Decreased cellular marrow elements with proportionally greater marrow fat content o Osteopenia on CT or plain radiography may help assist diagnosis

Helpful Clues for less Common Diagnoses • Hemangiomas (Multiple) o Fatty stroma within well-delineated benign indolent vertebral body tumors o Rarely a diagnostic dilemma • Distinct fat signal intensity masses within more conventional appearing marrow distinguishes from diffuse hyperintensity of fatty marrow involving entirety of vertebral body marrow • Paget Disease o Fibrovascular marrow in active phase • Heterogeneous but predominantly hypointense on Tl WI MR, hyperintense on T2WI MR • Interspersed foci of fatty marrow • Post-gadolinium enhancement helps distinguish from diffuse fatty marrow o Fatty marrow in mixed phase • Hyperintense on TlWl and T2WI MR • Most often imaged in this phase • Involved vertebral body may be increased in size compared to normal adjacent vertebrae

Post-Irradiation

SagiNal T7 c+ MR demanslIates diffuse ve,tebral marrow hyperintensity following craniospinal irradiaUon for CSFdisseminated aligoaslIocytoma metastases

=.

Vertebral Marrow

Sagittal T7WI MR shows typical bright T7 hyperintensity in the vertebral marrow at irradiated spina/levels in this patient with breast adenocarcinoma.

VERTEBRAL BODY, 11 HYPERINTENSE

SIGNAL,

DIFFUSE

CJl

"S!. :l

ct>

<
Normal Variant

,

Normal Variant (Left) Sagittal T7 WI MR in an elderly patient with diffuse falty marrow and spondylitic myelopathy shows diffuse marrow hyperintensity related 10 fat content. (Right) Sagittal T7WI MR in an older patient with post-operative spondylolisthesis at L4-5 reveals diffuse increased fally marrow signal intensity.

OJ

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o c. '<

m
3
:::l

en

Heterogeneous Fatty Marrow

Osteoporosis (Left) Sagittal T I WI MR demonstrates variant heterogeneous fatty marrow signal intensity in an elderly patient with multilevel degenerative disc disease. (Right) Sagittal T7WI MR shows diffusely increased fatty marrow signal inlensity with numerous compression fractures at multiple levels.

Marrow signal intensity within

the fractures

varies

from hypoinlense in the acute fractures =:I to hyperintense in a chronic fracture~.

(Left) Sagittal T7WI MR demonstrates one large and two small E!ilI fatty stroma vertebral hemangiomas. Diagnosis is slightly harder because of background mild diffuse fatty marrow content. (Right) Sagittal T7WI MR shows an abnormal L2 vertebral body =:I that is mildly enlarged in anteroposterior dimension, with slight height loss and T7 shortening from increased

=

marrow

fat.

II 3 49

VERTEBRAL BODY, 11 HYPERINTENSE

rn

C

SIGNAL,

FOCAL

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en

DIFFERENTIAL DIAGNOSIS Common • Normal Variant • Hemangioma • Degenerative Endplate Changes • Focal Fatty Marrow • Gadolinium Enhancement less Common • Paget Disease • Metastasis, Melanoma Rare but Important • Vertebral Marrow Hemorrhage

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Use fat saturation &/or STIR MR imaging to distinguish fat from other etiologies of 1'1 hyperintensity Helpful Clues for Common Diagnoses • Normal Variant o Heterogeneous marrow signal related to interspersed normal fat and hematopoietic elements in vertebral body • Hemangioma o Benign vertebral body vascular tumor with hyperintense 1'1 signal intensity o Usually incidental lesion identified on imaging performed for unrelated reasons • Degenerative Endplate Changes o Type 1: Hypointense on 1'1WI, hyperintense on T2WI

II 3 50

Type 2: Hyperintense on 1'1WI, isointense on T2WI o Type 3: Hypointense on 1'1WI and T2WI • Focal Fatty Marrow o Discrete focus of 1'1 hyperintensity representing macroscopic collection of fat interspersed with cellular marrow elements o Suppresses on fat-saturated or STIR MR imaging • Gadolinium Enhancement 01'1 shortening produces high 1'1 signal intensity o Chemical fat saturation or STIR MR imaging will not abolish 1'1 shortening (unlike fat) o

Helpful Clues for less Common Diagnoses • Paget Disease o Enlarged vertebra and neural arch with trabecular coarsening and cortical thickening • Metastasis, Melanoma o Melanotic metastases may demonstrate 1'1 hyperintensity on unenhanced 1'1WI MR Helpful Clues for Rare Diagnoses • Vertebral Marrow Hemorrhage o Subacute blood products will demonstrate 1'1 shortening o Consider underlying mass lesion (may be occult)

Sagilwl T1WI MR depic15 scallered foci of marrow hyperintensity, reflecting normal variation of vertebral

Sagillal T1WI MR reveals a hyperinlense L4 verlebral body lesion =:I without epidural expansion. T1

marrow

shortening represents the fatty stromal component.

comfXJsition.

VERTEBRAL BODY, 11 HYPERINTENSE SIGNAL, FOCAL

VI

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<

ell

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Degenerative

c:r ~

Endplate Changes (Left) Sagillal TI WI MR reveals focal fal =.:I adjacent to verlebral endplales al L4-5, characteristic of

degenerative

OJ

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disc disease

marrow changes. The fal merges with adjacenl erythropoietic marrow. (Right) Sagillal TlWI MR shows multilevel disc space narrowing and disc bulges in mid and lower lumbar spine. Note rally marrow adjacent to degeneraled endplales 8l a frequenl finding of degenerative disc disease.

Gadolinium

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en

Enhancement (Left) Sagittal T1WI MR demonstrates well-circumscribed focal fally verlebral marrow =.:I mimicking a vertebral hemangioma. (Right) Sagillal T1 C+ MR demonslrales an enhancing L3 colon carcinoma metastasis with posterior epidural extension. Signal intensity is similar to fat. Fat saturation techniques are useful to distinguish fal from enhancement.

=

Paget Disease

Vertebral

Marrow

Hemorrhage (Left) Sagillal T1WI MR shows an abnormal L2 vertebral body =.:I wilh mildly enlarged anteroposterior dimension, mild heigh I loss, and TI shortening from increased marrow fal. (Right) Axial T1 WI MR (aneurysmal bone

cyst) shows extensive cortical destruction around 1/2 of spinal canal and

severe canal compromise

by

tumor NOle mulliloculated mass containing mulliple fluid-fluid levels. Mixed signal intensity reflecls the presence of blood products.

II 3 51

en

VERTEBRAL BODY, 11 HYPOINTENSE

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DIFFERENTIAL DIAGNOSIS Common • Hyperplastic Vertebral Marrow • Normal Variant (Technical) • Neoplasm o Metastases, Blastic Osseous o Leukemia o Lymphoma o Multiple Myeloma Less Common • HIV

• SickJe Cell • Renal Osteodystrophy Rare but Important • Myelofibrosis • Osteopetrosis • Fibrous Dysplasia • Extramedullary Hematopoiesis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Determine whether there is diffusely abnormal hypointense vertebral marrow signal intensity or scattered patchy areas of hypointensity within multiple vertebra • Hypointense marrow appearance by itself is relatively nonspecific; look for ancillary clues that may permit a specific diagnosis

II 3 52

Helpful Clues for Common Diagnoses • Hyperplastic Vertebral Marrow o Physiologic process in which fatty marrow is converted to red marrow in response to systemic stress o Intervertebral discs are hyperintense compared to vertebral marrow on Tl WI • Normal Variant (Technical) o Marrow demonstrates hypointense signal artifactually due to MR pulse sequence technique o Commonly observed when Tl FLAIR imaging is used at higher field (2; 3T) imaging to reduce patient heating related to specific absorbed radiation (SAR) o Tl FLAIRproduces lower marrow signal intensity in normal bone marrow compared to that observed using spin echo or fast spin echo Tl WI MR technique

SIGNAL,

DIFFUSE

• Less likely to produce erroneous diagnosis of marrow infiltration as radiologist gains experience using this technique • Neoplasm o Metastases, Blastic Osseous • Hematogenous systemic dissemination (arterial or venous via Batson plexus) > perineural, lymphatic, CSF spread • Marrow initially infiltrated, trabeculae destroyed, then subsequently bone cortex destroyed • Blastic rather than lytic presentation occurs when bone production exceeds bone destruction o Leukemia • Acute or chronic, myeloid or lymphoid white blood cell neoplasia with spinal involvement as component of systemic disease burden • Single or multiple vertebral involvement • Most common (classic) spinal presentation is diffuse osteopenia with multiple vertebral fractures ± lytic spine lesions o Lymphoma • Lymphoreticular neoplasms with wide variety of specific diseases & cellular differentiation • Variable imaging manifestations o Multiple Myeloma • Multifocal malignant proliferation of monoclonal plasma cells within bone marrow • Multifocal, diffuse, or heterogeneous Tl hypointensity; may be diffusely hypointense in high disease burden, particularly if accompanied by severe anemia Helpful Clues for Less Common Diagnoses • HIV

Marrow hypointensity reflects generalized anemia • Need high index of suspicion to specifically diagnose in absence of ancillary findings • Sickle Cell o Hereditary hemoglobin abnormality resulting in anemia, deformed (sickle) red cells that occlude blood vessels o

VERTEBRAL BODY, 11 HYPOINTENSE

SIGNAL,

DIFFUSE

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Classic imaging appearance: Marrow hypointensity with multiple H-shaped vertebral bodies o Differing disease severity depending on hemoglobin subtype(s) and whether patient is homozygous or heterozygous • Homozygous: HbSS (sickle cell anemia) • Heterozygous: HbSA (sickle cell trait, asymptomatic), HbSC (less severe form) o Sickle cell crisis: Acute episode of severe bone, abdomen, chest pain • Renal Osteodystrophy o Bony changes attributable to chronic, end-stage renal disease o Secondary hyperparathyroidism (HPTH), osteomalacia, bone sclerosis, aluminum toxicity contribute to findings o Best diagnostic imaging clue: "Rugger jersey" spine o

Helpful Clues for Rare Diagnoses • Myelofibrosis o Very low signal intensity noted in bone marrow on all MR pulse sequences o Myelodysplastic syndromes: Myeloproliferative disorders that may show myelofibrosis at some point in their evolution • "Primary" form may be a precursor to polycythemia vera and chronic myeloid leukemia • More commonly reflects a secondary phenomenon secondary to leukemia, lymphoma, or metastatic tumor

• Osteopetrosis o Heterogeneous grouping of hereditary osteoclast disorders o Diffuse increase in bone density and thickened bone cortex involving entire skeleton • Fibrous Dysplasia o Best diagnostic clue: Mildly expansile lesion with ground-glass bone matrix o Monostotic: Single bone lesion only • Monostotic disease usually an incidental finding o Polyostotic: Bone lesions in multiple bones • Usually presents in first or second decade • Often associated with growth disturbances, pathological fractures through abnormal weakened bone o McCune-Albright syndrome: Polyostotic FD, precocious puberty, cafe-au-Iait skin lesions • Extramedullary Hematopoiesis o Epidural ± paravertebral proliferation of hematopoietic tissue in response to profound chronic anemia o Minimally enhancing isointense thoracic intra- or paraspinal soft tissue masses in conjunction with diffuse marrow hypointensity o Consider when thoracic epidural/paraspinal isointense masses detected in patients with hemoglobinopathies or myeloproliferative disorders

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Normal Variant (Technical)

T1 WI MR in caudal

Axial T1WI MR in a chronic anemia patient shows

Sagittal

homogeneous

artifactual

hYfXJintense

vertebra and iliac wing bone

marrow signal inlensil~ darker than the adjacent

recovery

muscles.

patient

diffuse marrow

regression

hYfXJintensity

IT1 FLAIR) pulse sequence heating at 3.0 Tesla.

syndrome

shows

on T1 inversion

II 3

used to limit SAR &

53

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SIGNAL,

DIFFUSE

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metastatic

infiltration

marrow

CD

signal intensity. There is an epidu,al mass at L4 (RighI) Sagittal T1WI MR shows ma,kedly decreased signal within all ve,teb,al bodies and poste,io, elements, with reversal of the usual adult disc/ve,teb,al body ,elationship (i.e., disc is usually da,ke, than ve,teb,al

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Metastases,

Blastic Osseous

of bone

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CO .0

Blastic Osseous

(Lefl) Sagittal T1 WI MR demonst,ates diffuse manifesting

low

=.

marrow).

leukemia

leukemia

(Lefl) Sagittal T1WI MR in a patient with chronic myelogenous leukemia shows diffuse hypoplastic ma"ow signal T 1 C+ MR (not shown) showed diffuse marrow enhancement (RighI) Sagittal T1WI MR reveals diffuse marrow replacement marrow

manifesting

signal intensity

as lower

than that of adjacent intervertebral discs.

HIV (Lefl) Sagittal T1WI MR shows diffuse, homogeneous, hypoinlense marrow signal and multiple vertebral compression fractures.

Severe

compression

present at L2

fracture

is

=. Fractures

also involve superior endplates of L4 and L5. (Rigilt) Sagittal T1 WI MR demonstrates mild marrow hypointensity in an AIDS patient

with chronic

anemia

and CMV poly,adieulopathy

II 3 54

VERTEBRAL BODY, T1 HYPOINTENSE

SIGNAL, DIFFUSE

<

(1)

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Sickle Cell (Left) Sagiltal Tl WI MR shows diffuse hypointense marrow signal intensity and central endplale depressions at multiple levels. Diffuse low marrow

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signal indicates

hemosiderin deposition from multiple transfusions or myelofibrosis. (Right) Sagiltal TlWI MR demonstrates low marrow signal intensity within the vertebral bodies and multiple endplate compression

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fractures.

(Left) Sagittal Tl WI MR

shows homogeneous low bone marrow

secondary

signal intensity

to fibrosis.

Marrow signal intensity is lower than the intervertebral disc signal, indicating this is not erythropoietic

marrow.

(Right) Sagittal TlWI MR depicts typical homogeneous, markedly hypointense vertebral marrow in a patient with myelofibrosis.

Osteopetrosis (Left) Sagiltal T2WI MR shows dense, sharply demarcated bands of low signal intensity due to bony sclerosis. Note that sclerosis and trabecular thickening are also present centrally in the vertebral bodies. Tl WI would show similar low signal intensity. (Right) Sagiltal T I WI MR reveals hypoinlense marrow signal in the clivus and odontoid process in this patient with polyostotic fibrous dysplasia.

II 3 55

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VERTEBRAL BODY, 11 HYPOINTENSE

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SIGNAL,

FOCAL

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DIFFERENTIAL DIAGNOSIS Common • Basivertebral Vein • Schmorl Node • Bone Island • Hemangioma (Atypical) • Fracture • Surgical Material o Metallic Hardware o Bone Cement • Osteomyelitis, Pyogenic • Osteomyelitis, Granulomatous • Degenerative Endplate Change (Types 1 & 3) • Metastases • Multiple Myeloma Less Common • Limbus Vertebra • Kummell Disease Rare but Important • Vertebral Pneumatocyst

ESSENTIAL INFORMATION Helpful Clues for Diagnoses • Basivertebral Vein o Linear or triangular structure projecting ventrally from the center of the posterior body • Schmorl Node o Hypointense Tl, variably hyperintense T2, circumscribed vertebral body lesion o In continuity with an adjacent disc space

Schmorl

• Bone Island o Focal sclerotic lesion, markedly hypointense on all sequences, with normal marrow signal elsewhere o CT may be useful to confirm diagnosis • Hemangioma (Atypical) o Some lipid-poor hemangiomas are isointense or hypo intense to marrow on TlWI o Bone algorithm CT can assess for characteristic bony features (thickened vertical trabeculae) • Fracture o Fracture line often difficult to delineate on MR o Associated marrow edema hypointense on TlWI • Osteomyelitis, Pyogenic o Hypointense Tl marrow signal adjacent to the level of infection • Metastases o Nearly all metastases hypointense on Tl WI, whether blastic or lytic o Multiple lesions typical • Limbus Vertebra o Unfused fragment of the ring apophysis, usually anterosuperior vertebral margin o Mid-lumbar most common • KiimmelJ Disease o Post-traumatic osteonecrosis o Horizontal, gas-filled intravertebral cleft is a characteristic finding; appears as signal void on MR

Node

Bone Island

II 3 56

Sagittal T7WI MR shows circumsuibed L2 vertebral body lesion, isointense to disc material, in contact with the L1-2 disc space.

Sagittal T7WI MR shows iocalsignal void within anterior

L4 body, without reactive marrow change or other marrow abnormality.

VERTEBRAL BODY, 11 HYPOINTENSE

SIGNAL, FOCAL

< C1> ;:+ C1>

rr ~ (Left) Sagittal T1 WI MR shows L5 body lesion with diffusely hypointense T1 signal I:] and extension into the ventral epidural space. T2WI (not shown) had typical vertical striations of

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hemangioma.

Heterogeneous lesion of L 7 was also a hemangioma. (Right) Sagittal T1WI MR shows horizontally oriented (racture extending through vertebral body ='2 and posterior elements ~ (Chance fracture) in MVA patient with ankylosing spondylitis.

Metallic

m

CD 3 C1> OJ

Ui

Hardware (Left) Sagittal T1 WI MR shows signal void adjacent to the C5-6 disc space, demonstrating the presence of an intervertebral disc prosthesis. (Right) Sagittal T1 WI MR shows hypointense marrow

signal in L3 and L4

!C associated

with destructive endplate changes and epidural phlegmon ='2.

Degenerative

Endplate Change (Types 1

&3)

Metastases (Left) Sagittal T1 WI MR shows hypointens€ signal in inferior endplale marrow of L5 ='2 associated with

advanced degenerative changes in the L5-S7 disc space. (RighI) Sagittal T1 WI MR shows multiple metastatic

lesions in cervical

and thoracic vertebral bodies

='2.

II 3 57

SEClilON 4 Intervertiebral Disc - Endplatie Generic Imaging Patterns Disc Contour Abnormality Intervertebral Disc/Endplate Irregularity Vertebral Endplate Contour Abnormality

Modality-Specific

11-4-2 11-4-6 11-4-10

Imaging Findings

Intervertebral Disc, T1 Hypointense Intervertebral Disc, T2 Hyperintense Vertebral Endplate Signal Abnormality

11-4-12 11-4-14 11-4-16

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DISC CONTOUR

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ABNORMALITY

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DIFFERENTIAL DIAGNOSIS Common • Intervertebral Disc Bulge • Disc Pseudobulge • Protrusion, Intervertebral Disc o Cervical o Thoracic o Lumbar • Extrusion, Intervertebral Disc o Cervical o Thoracic o Lumbar • Free Fragment, Intervertebral Disc o Cervical o Thoracic o Lumbar • Intervertebral Disc Extrusion, Foraminal • Intervertebral Disc Herniation, Recurrent • Peridural Fibrosis • Osteophyte • OPLL • Epidural Mass o Metastasis o Lymphoma o Epidural Abscess o Epidural-Subdural Hematoma Less Common • Discal Cyst • Hardware Malposition • Meningioma (Calcified) • Schwannoma (Foraminal) • Limbus Vertebra

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Main differential point is whether or not lesion is contiguous to the intervertebral disc, or abutting the disc o Additional key findings include signal on Tl, T2 images relative to nearby intervertebral disc; presence or absence of enhancement o Large extrusion and protrusion should not have homogeneous or intense central enhancement

II 4 2

Helpful Clues for Common Diagnoses • Intervertebral Disc Bulge o Circumferential disc "expansion" beyond the confines of vertebral end plates

o

•

•

•

•

•

•

•

> 50% of disc circumference

Up to 40% of asymptomatic adults will have bulging disc o Short radius of extension beyond disc margin :$ 3 mm Disc Pseudobulge o "Uncovering" of disc related to spondylolisthesis o Smooth generalized extension of disc margin without focal defect Protrusion, Intervertebral Disc o Triangular focal disc abnormality with base broader than apex o Anterior extradural mass in contiguity with the disc space Extrusion, Intervertebral Disc o Base of herniation is narrower than portion extending into epidural space o May be associated with sequestered or "free fragment" o Larger extrusion commonly show peripheral enhancement with granulation tissue Intervertebral Disc Extrusion, Foraminal o Obliterated perineural fat in neural foramen on sagittal images o May enhance peripherally o Contiguous to disc on parasagittal images Intervertebral Disc Herniation, Recurrent o Contiguous with intervertebral disc margin o Central lack of enhancement, with peripheral granulation tissue enhancement common o Distinguish from peridural fibrosis by nonenhancing component, mass effect Peridural Fibrosis o Scar formation within epidural space after lumbar surgery o Infiltration of epidural/perineural fat by enhancing soft tissue density (intensity) o Smooth marginated soft tissue, usually without mass effect o Typically slightly increased in T2 signal relative to disc herniation o Homogeneously enhances Osteophyte o Variable in MR signal due to relative presence of bone, red marrow, or fatty marrow o Often associated with disc degeneration and disc bulge/herniation o

DISC CONTOUR ABNORMALITY Typical "claw" configuration from adjacent endplates • OPLL o Flowing multilevel ossification posterior to vertebral bodies o Narrows AP dimension of canal and produces cord compression o May show low T1 signal (cortical bone) or high T2 signal (fatty marrow) o Typical "upside down T" or "bowtie" configuration on axial images • Epidural Abscess o Epidural mass with peripheral enhancement o Associated with findings of disc space infection (endplate irregularity and erosion, disc and body T2 hyperintensity, irregular enhancement) • Epidural-Subdural Hematoma o Acute may show isointense Tl signal, with subacute Tl hyperintense o Long segmental extra-axial mass encasing or displacing cord or cauda equina o Rarely focal, as when associated with focal fracture or disc extrusion o

Helpful Clues for Less Common Diagnoses • Discal Cyst o Uncommon finding with degenerative disc disease o Focal area of fluid signal intensity adjacent to intervertebral disc margin o May reflect evolution of disc herniation with hemorrhage

Intervertebral

Axial

T2WI MR shows

generalized extension vertebrallxxiy

L5-57 disc bulge

BI

as

disc margin beyond the

margin, without focal deformity.

•

•

•

•

o

en

()

Disc Pseudobulge

Disc Bulge

or the

May spontaneously regress Hardware Malposition o Pedicle screw position may extend into intervertebral disc o Look for low signal of metal implant with halo of high signal (spatial mismapping) o Precise position of screw tip requires CT Meningioma (Calcified) o Intradural-extramedullary lesion, not extradural o Large calcified lesion may be difficult to define as intradural o Large amounts of calcification may minimize enhancement Schwannoma (Foramina I) o Generally not ventral to thecal sac, but arise along foramen with intradural and extradural components (dumbbell configuration) o May be difficult to distinguish from lateral herniation • More solid enhancement than large herniation • May show cystic change Limbus Vertebra o Intraosseous disc herniation at junction of cartilaginous end plate o Unfused apophyseal fragment at vertebral margin o Anterior more common and posterior o If posterior, consider limbus herniation with fracture of the end plate/apophysis o

Sagittal T1WI MR shows degeneration L5-S7 with type I endplale changes. There is "uncovering" of posterior aspect of disc with thecal sac deformity. Note L4-5 retrolisthesis with uncovering of inferior disc margin ~.

=

II 4 3

DISC CONTOUR

:ffi0-

ABNORMALITY

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W Ll (/)

Extrusion, Intervertebral

o

Q)

C

'Q. (Jl

Disc

Extrusion, Intervertebral

Disc

(Left) 5agillal T2WI MR shows multiple midthoracic disc extrusions, severely compressing thoracic cord. Extrusions show typical pallern of larger componenl in epidural space than at disc base. (RighI) 5agillal T2WI MR shows large extrusion with free fragment al L5-5 I, with inferior migration A small protrusion is present at L4-5S1. L5-51 disc is degenerated

c=.

Intervertebral Disc Herniation, Recurrent (Left) 5agillal T1WI MR shows large eXlraforaminal extrusion which is contiguous with the parent intervertebral disc and obscures the foramina! fat

-=

and

exiling

nerve root

Compare with the normal foramen below. (Right) Axial T1 C+ MR shows large, right

paracentral recurrent herniation with a small amount of peripheral enhancing epidural fibrosis. The exiting root is effaced and nol separately identified.

(Left) Axial T1 WI MR shows ill-defined soft lissue along the course of the exiling right L5 root l:lI due 10 post·operalive fibrosis. (RighI) Axial T1 WI MR shows large, well-defined focus of very low signal

posterior to disc margin

m

due 10 OPLL. There is severe spinal cord deformalion l:lI.

II 4 4

DISC CONTOUR

en

ABNORMALITY

"::J CD

Epidural Abscess (Left) SagiLLalT2WI MR shows destfllction of LS & S I centered at the disc leve/, with anlerolisthesis

of L5 on

=-

S 1 and effacement of thecal sac and prevertebral soft tissue Ell. (Right) Sagillal T2WI MR shows well-defined fluid signal intensity Ell at the site of herniation on a prior study (not shown). This may reflect involution

hemorrhage

o (ii. Cl

m ::J

a. "2OJ

CD

of a prior

within the disc

herniation.

(Left) SagiLLalT1 WI MR shows linear low signal from anterior

screw ~

extending

into the ventral aspect of the

spinal canal. Note the slight high signal halo at the screw tip. (Right) SagiLLalT2WI MR shows a heavily calcified cervical

meningoma

seen as

lobular low signal mass ~ with broad dural margin. Obtuse CSF margin could be confusing for OPLL or herniation.

limbus Vertebra

limbus Vertebra (Left) SagiLLalT2Wl MR shows limbus herniation with focal contour defect at the thoracolumbar

junction

=.

Defining limbus avulsion or herniation

is difficult

without

CT confirmation. (RighI) Axial N[CT shows limbus fracture 0(( of the posterior superior margin with mild mass effect upon thecal sac.

II 4 5

INTERVERTEBRAL DISC/ENDPlATE

DIFFERENTIAL DIAGNOSIS

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Common • Degenerative Disc Disease • Degenerative Endplate Changes (Modic Changes) • Schmorl Node • Accelerated Degeneration • Scheuermann Disease • Pyogenic Disc Space Infection • Tuberculous Disc Space Infection • Fungal Infection (Coccidiomycosis) • Rheumatoid Arthritis less Common • Neurogenic (Charcot) Arthropathy • Ankylosing Spondylitis • Brucellosis • Bone Infarcts o Sickle Cell o Gaucher • Post-Treatment: Bone Morphogenetic Protein • Hemodialysis Spondyloarthropathy Rare but Important • Gout • Spondyloepiphyseal • Ochronosis

Dysplasia

ESSENTIAL INFORMATION

II 4 6

Key Differential Diagnosis Issues • Primary consideration is infection vs. other o Classic pattern of disc space infection includes • Endplate irregularity • Loss of distinction of disc margin and end plate on Tl weighted images • Abnormal T2 signal disc hyperintensity • Abnormal T2 vertebral body hyperintensity • Abnormal irregular enhancement of the disc o Epidural enhancing soft tissue (phlegmon) or rim-enhancing mass (abscess) definitive findings o Fat-suppressed T2 images &/or fat-suppressed post-contrast Tl images especially useful for evaluation of paraspinal and epidural soft tissues

o

IRREGULARITY

Severe degenerative endplate changes may be associated with end plate irregularity and fluid within disc giving T2 hyperintensity • Should not see epidural soft tissue or paraspinal soft tissue Definite overlap in MR findings between early disc space infection and severe degenerative endplate changes => biopsy required

Helpful Clues for Common Diagnoses • Degenerative Disc Disease/Endplate Changes o Disc hypointense on Tl WI and T2WI o Endplates may be irregular, with Schmorl nodes, but margin between disc and vertebral body preserved o Mild post-gadolinium enhancement, often linear along endplate margins in horizontal direction o No paravertebral or epidural soft tissue to suggest infection • Schmorl Node o Well-defined, smoothly marginated end plate herniation o May see variable marrow signal around it, depending upon age of insult • Acute shows t STIR, chronic shows normal or fatty marrow halo • Accelerated Degeneration o Aberrant biophysical stresses from altered normal spinal motion/fusion o Wolff law; living tissue responds to chronic changes in stresses & strains o Increased mobility in remaining mobile segments is hypothesized to cause accelerated degenerative pathologic changes • Scheuermann Disease o Kyphosis secondary to multiple Schmorl nodes --> vertebral body wedging o Three or more wedged thoracic vertebrae with irregular endplates o Thoracic spine pain and tenderness worsened by activity in teenager, young adult • Pyogenic Disc Space Infection o Severe endplate irregularity with loss of distinction of disc from end plate o t T2 signal from disc, endplate, ± vertebral body

INTERVERTEBRAL DISC/ENDPLATE IRREGULARITY Paravertebral and epidural soft tissue • Tuberculous Disc Space Infection o Endplate irregularity and osteolysis o Multiple (non)contiguous vertebrae involved, including posterior elements o Migration of phlegmon underneath all with erosion of vertebral body corners o May mimic metastatic disease • Fungal Infection (Coccidiomycosis) o Variable appearance from small focal body involvement ~ gross vertebral body/disc destruction o Multiple bodies involved, similar to TB • Rheumatoid Arthritis o C1-C2 instability in 33% of all RA patients o Facet and uncovertebral joint erosions o Multilevel subluxations, uncommon disc and adjacent vertebral body destruction o

Helpful Clues for Less Common Diagnoses • Neurogenic (Charcot) Arthropathy o 4 of classic "S Os" related to spine: ormal density bone, destruction, disorganization, debris • Ankylosing Spondylitis o Endplate irregularity with acute inflammation phase, or chronic with fusions and Schmorl node formation o Irregularity with chronic fracture and pseudoarthrosis development • Brucellosis o Granulomatous osteomyelitis pattern o May see pattern mix similar to pyogenic w/disc involvement, + skip lesions like TB

Degenerative Disc Disease

• Bone Infarcts o Sickle cell & Gaucher disease: "H-shaped" vertebral bodies o May see only vertebral collapse with Gaucher • Post-Treatment: Bone Morphogenetic Protein o Bone morphogenetic protein (rhBMP-2) bone lytic resorption defects occur at fusion sites in up to 1/3 patients o Transforming growth factor acts as signaling molecule to attract mesenchymal stem cells • Binds to receptors and causes stem cells to differentiate into osteoblasts with bone formation • Hemodialysis Spondyloarthropathy o Peridiscal destructive arthritis in patient on long-term hemodialysis

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Cl. "0

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ro

Helpful Clues for Rare Diagnoses • Ochronosis o Deposition of homogentisic acid and its metabolites secondary to absence of homogentisic acid oxidase enzyme o Premature degenerative disc disease with calcified intervertebral discs o Osteopenia and spinal ankylosis Other Essential Information • SED: Group of disorders (congenita, tarda) characteristic defect in epiphyses, which appear irregular o Likely relate to collagen II (COL2A1 gene) mutations Degenerative Endplate Changes (Modic Changes)

II

=-

Sagitlal T2WI MR shows endplate irregularity T12-L1 due to disc degeneravon and irregularity at 13-4

from Schmorl node ~.

There is multilevel severe

central stenosis. Note L1 hemangioma.

Sagittal T1WI MR shows multilevel severe disc degeneration with type II endplate changes There is diffuse irregularity of the endplates at these levels.

=.

4 7

INTERVERTEBRAL DISC/ENDPlATE

Q)

ro Q.

IRREGULARITY

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Accelerated

Degeneration

Scheuermann

Disease

(Lefl) Sagiflal T2WI MR shows C4-S anterior fusion with concomitant severe disc degeneration al CS-6 =:lI with loss of disc signal, endplate irregularity, & loss of disc heigh/. (RighI) Sagiflal bone CT shows endplale irregularities and vertebral wedging SI bUI no widening of paraspinous soft tissues. The vertebral endplate depressions have an undulating

contour.

Tuberculous

Disc Space Infection

(Lefl) Sagiflal T1 C+ MR shows nonenhancing necrotic bone extending into superior LS endplale !::I & ven1ral epidural phlegmon =:lI. L3-4 disc space infeclion shows irregular endplate enhancement ~ (RighI) Sagitwl T2WI MR shows multifocal verlebral body disease SI and disc involvement

with irregularity

=:lI & subligamenlous extension.

Rheumatoid (Lefl) Sagiltal T2WI MR shows minor disc involvement at C6-7 =:lI with extensive prevertebraf

component above and below that disc level SI. Note the extensive focal body involvemenl of C7. (RighI) Sagiltal STIR MR shows erosive changes of C 1 and odontoid process with peridental pannus with effacement of thecal sac. There is subaxial endplate irregularity most pronounced al C3-4 =:lI.

II 4 8

Arthritis

INTERVERTEBRAL DISC/ENDPlATE

IRREGULARITY

(Lefl) Coronal bone CT shows typical appearance of Charcot arthropathy of the lumbar spine with proliferative

new bone

E!:I and lucent pseudoarthrosis extending transversely across all formation

columns. (RighI) Sagittal T2WI MR shows a pronounced fracture

oblique

involving

=

thoracic spine irregular fracture

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chronic

the lower

with the site

functioning as a pseudoarthrosis.

Post-Treatment: Sickle Cell

Bone Morphogenetic Protein (Lefl) Sagittal T1 WI MR shows typical MR

appearance

of vertebrae in

sickle cell disease with H-shaped vertebrae Ell and marrow low signal due to hemosiderin

deposition

from

multiple transfusions. (RighI) Sagittal T2Wt MR shows multiple

small "cystic"

appearing lesions with T2

hyperintensity involving the L5 and S I bodies. Note the smooth margins, with abrupt transition marrow

to more normal signal, and lack of

adjacent

Hemodialysis

marrow

edema.

Spondyloarthropathy (Lefl) Lateral radiograph shows destructive crystal arthropathy at C4-5 simulating

infection.

There is

diffuse endplate irregularity Ell. Soft tissue calcifications indicate

crystal deposition

J:!J. (RighI) Sagittal T2WI MR shows a 50 year old with epiphyseal dysplasia with diffuse platyspondyly with rectangular-shaped vertebral bodies and endplate

irregularity.

II 4 9

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ro 0.

VERTEBRAL ENDPLATE

CONTOUR

ABNORMALITY

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• Limbus Vertebra: Small separate corner portion of endplate, well-marginated • Fracture: Angular deformity of end plate, ± visible fracture line • Scheuermann Disease: Undulating end plates 4 or more levels + kyphosis, with or without discrete Schmorl nodes • Osteomyelitis: Endplate erosion, vertebral body destruction, osteopenia or osteosclerosis • Sickle Cell: Depression central portion of endplate ("Lincoln Log")

DIFFERENTIAL DIAGNOSIS

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Common • Schmorl Node • Degenerative Endplate Changes • Limbus Vertebra • Anterior Compression Fracture • Lateral Compression Fracture • Scheuermann Disease • Osteomyelitis, Pyogenic • Sickle Cell Less Common • Neurogenic (Charcot) Arthropathy • Osteomyelitis, Granulomatous • Cushing Disease • Osteogenesis Imperfecta • Achondroplasia • Mucopolysaccharidoses • Thanatophoric Dwarfism • Spondyloepiphyseal Dysplasia

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • May be due to trauma, developmental or congenital disorders, degenerative disease or infection Helpful Clues for Common Diagnoses • Schmorl Node: Cup-shaped defect in endplate • Degenerative Changes: Osteophytes may elongate or form hook adjacent to endplate

Helpful Clues for Less Common Diagnoses • Neurogenic Arthropathy: Mimics osteomyelitis; endplate destruction and erosion, non united fracture fragments, heterotopic ossification • Osteomyelitis, Granulomatous: Vertebral endplate destruction and deformity, but disc spaces preserved until late; may involve multiple levels; bone fusion and kyphosis • Cushing Disease: C-shaped end plate ("fish mouth") • Osteogenesis Imperfecta: Variable flattening and deformity due to fractures; severe osteopenia • Achondroplasia, Mucopolysaccharidoses: Anterior beak deformity • Spondyloepiphyseal Dysplasia: Vertebrae flattened but taller in center than at sides

Degenerative

II 4 10

Sagiltal T1WI MR shows cup-shaped

deformity

endplate and normal marrow signal intensity.

=

of

Endplate Changes

Coronal bone CT shows advanced degenerative disc disease, with endplate irregularities and subchondral cysts. Endplate remodeling is partiy due to scoliosis in this p<1lient.

VERTEBRAL ENDPlATE

Anterior

Compression

Fracture

CONTOUR

Scheuermann

ABNORMALITY

Disease (Lcfl) Sagittal T1 WI MR shows an L2 compression fracture.

Anterior

portion

of

cndplate is depressed I:] with cortical stepo(f. Oblique fracture line ~ is surrounded by low signal edema. (Righi) Sagillal T1WI MR shows undulating vertebral endplates and mild wedging o( 6 adjacent vertebral bodies ~. Although endplates are abnormal in contour, their signal intensity is normal.

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Achondroplasia (Lefl) Sagittal bone CT shows large L3-L4 endplate erosions much more severe than seen with degenerative disease. Sclerosis of vertebrae adjacent to erosions is a common finding in vertebral osteomyelitis. (RighI) Sagittal T1 WI MR shows bullet-shaped vertebrae at thoracolumbar junction, resulting in kyphotic deformity 1:]. De(ormity is less widespread than in mucopolysaccharidoses.

=-

Mucopolysaccharidoses (Left) Sagittal bone CT shows flattened

vertebrae

with

anterior beaking characteristic of Morquio

syndrome 1:]. (RighI) Coronal bonc CT shows mildly flallened vertebrae with undulating endplatc contours. extremity radiographs showed flallened epiphyscs, corroborating diagnosis.

II 4 11

Q)

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INTERVERTEBRAL

DISC, T1 HYPOINTENSE

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DIFFERENTIAL DIAGNOSIS Common • Congenital Vertebral Body Fusion • Degeneration/Calcification • Degeneration/Vacuum Phenomenon • Osteophyte • Instrumentation/Implants less Common • Kummell Disease • Pseudoarthrosis o Neurogenic (Charcot) Arthropathy o Post-Traumatic Instability o Post-Operative Spinal Complications

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Congenital Vertebral Body Fusion o Linear small low signal disc with "wasp waisting" of vertebral bodies • Degenerative Disc Disease o Calcification or vacuum phenomenon within intervertebral disc o Loss of disc space height, vacuum phenomenon seen as low signal within disc on TlWI o Decreased signal of intervertebral disc on T2WI, loss of central nucleus high signal classic findings of disc degeneration • Osteophyte o Variable appearance due to type of marrow, degree of cortical bone

May show linear low signal on all pulse sequences with dense cortical bone o Larger osteophytes may contain fatty marrow with t Tl signal o Claw-like appearance contiguous with end plates/ disc • Instrumentation/Implants o Low signal with distortion and spatial mismapping of signal ~ high signal surrounding halo o Small amount of metal artifact may give significant artifact, not visible on CT/plain films • Typical following cervical discectomy o

Helpful Clues for less Common Diagnoses • Kiimmell Disease o Nonunited vertebral body fracture undergoes secondary necrosis and collapse o Nitrogen accumulates in fracture cleft o Usually elderly, osteoporotic patients o Low signal on Tl WI from gas, variable high signal T2WI, STIRfrom body • Neurogenic (Charcot) Arthropathy o Destructive arthropathy when pain and proprioception are diminished/lost, while joint mobility is maintained o Preserved bone density, bony debris best seen on CT, helps distinguish from infection o Lumbar spine, rapidly progressive, vacuum phenomenon

Degeneration/Vacuum

Phenomenon

II 4 12

Sagittal T2WI MR shows L1-2 congenital

=

fusion with

rudimentary linear low signal intervertebral disc mild kyphotic angular deformity:

and

Sagittal TI WI MR shows low T1 signal (rom endplates & disc at L5-57 due to combined disc degeneration/gas & adjacent type 111marrow change Note type If endplate change L2-S and Schmor! nodes.

=.

INTERVERTEBRAL DISC, T1 HYPOINTENSE

(Left) Sagittal TI WI MR shows horizontal low signal at LS-Sllevel due to a large osteophyte extending

=

into the inFerior neural

o (fJ ()

foramen 8l displacing the exiting L5 root. (Right) Sagittal T I WI MR shows metal artifact from Bryan cervical disc prosthesis made from 2 titanium alloy porous coated shells. Note low signal artifact with spatial mismapping with increased signal halo.

=

Instrumentation/I

mplants

Kiimmell

Disease (Left) Axial TI C+ MR shows post-operative changes following imerbody fusion and posterior pedicle screw fixation with low signal from the graft cages and adjacent hardware EJ. (Right) Sagittal T1WI MR shows severe vertebral collapse with gas-filled vertebral body cleft EJ and vacuum disc phenomenon

=

I!:J.

Pseudoarthrosis (Left) Sagittal T1 WI MR shows solid fusion at L4-5. Pseudoarthrosis seen as irregular low signal extending through L5 disc space and posterior elements with fusion above and below that level. (Right) Sagittal T1 WI MR shows typical MR appearance of neuropathic arthropathy with anterolisthesis and sharply demarcated endplate

=

erosions=.

II 4 13

INTERVERTEBRAL

Q)

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DIFFERENTIAL DIAGNOSIS Common • Normal Variant • Degenerative Disc Disease • Vertebral Disc Anular Tear • Post-Operative Change, Normal • Post-Traumatic • Disc Space Infection less Common • Pseudoarthrosis o Neurogenic (Charcot) Arthropathy o Seronegative Spondyloarthropathy

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Normal Variant o Central disc shows biconvex central high signal o Horizontal low signal extends through nucleus giving bisaucer shape o Loss of central signal with disc degeneration • Degenerative Disc Disease o Typical decreased signal of intervertebral disc on T2WI o May show linear T2 hyperintensity with fluid-filled cleft in disc o Uncommon discal cysts along posterior margin o No paravertebral or epidural mass to suggest infection • Vertebral Disc Anular Tear Normal Variant

II 4 14

Sagittal T2WI MR shows normal hyperintensity of L2-3, L3-4 discs with horizontal central low signal (intranuclear cleft). There is degeneration and loss of signal of L4-S, LS·Sl 81.

=

DISC, 12 HYPERINTENSE Focal increased signal in anulus on T2WI with low signal of parent disc o Tl C+: Focally enhancing nidus in posterior disc margin o Discography demonstrates contrast leak from central site of injection through anulus o Discography is more provocative test (symptom simulation) than diagnostic imaging modality • Post-Operative Change, Normal o Disc intervention may lead to increased fluid and T2 hyperintensity o Nonspecific post-operative change • Post-Traumatic o t T2 signal suggests disc disruption o Look for disruption of ALL, PLL • Disc Space Infection o Abnormal disc t T2 with abnormal morphology hallmark of disc space infection o 2 adjacent vertebrae involved with end plate irregularity and intervening disc abnormality o Paraspinal ± epidural infiltrative soft tissue ± loculated fluid collection o

Helpful Clues for less Common Diagnoses • Neurogenic (Charcot) Arthropathy o Irregular disc space fluid, facet involvement, spondylolisthesis, debris, disorganization

Degenerative

Disc Disease

Sagittal T2WI MR shows disc T2 hyperintensity related to degeneraUon with fluid·filled cleft This is T2

=.

hyperintensity associated with degeneration and not disc space infection.

INTERVERTEBRAL DISC, 12 HYPERINTENSE

Degenerative

Disc Disease

Vertebral

Disc Anular Tear (Left) Sagittal T2WI MR shows a well-defined fluid signal intensity at dorsal disc margin a. consistent with a "discal cysl". This may reflect involution

of a prior

disc herniation hemorrhage. (Right) Sagittal T2WI MR shows anufar tears as focal

hyperintensity within dorsal anulus =:I. There is mild degeneralion of L3-4 through L5-sl with signal loss.

Vertebral

Disc Anular Tear

Post-Operative

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Change, Normal (Left) Sagittal T2WI MR shows linear T2 hyperintensity from ventral anular lears al L2-] and L3-4 ~. NOle type I endplale change al L5-sl wilh spondylolisthesis. (Right) Sagittal STIR MR shows L4/5 pur There is fluid signal intensity in Ihe L4/5 disc interspace adjacenlto graft

= which can be normal.

Also large dorsal soft tissue abnormality SI relaled to pseudomeningocele with hemorrhage.

Post-Traumatic (Left) sagillal STIR MR shows severe burst fracture involving Ihe L1 body wilh disc hyperinlensily =:I, with marked posterior bony retropulsion and severe

thecal sac compression ~. (Right) Sagittal STIR MR shows T2 hyperinlensily of

intervertebral disc and adjacent verlebral bodies from pyogenic infection. There is facet involvement

SI and epidural abscess =:I.

II 4 1S

VERTEBRALENDPLATESIGNAL ABNORMALITY

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DIFFERENTIAL DIAGNOSIS Common • Degenerative Endplate Changes • Schmorl Node • Pyogenic Osteomyelitis • Wedge Compression Fracture • Post-Treatment o Post-Operative Infection o Post-Operative Instability o Post-Operative Degenerative Endplate Changes • Pseudoarthrosis o Post-Traumatic o Neurogenic (Charcot) Arthropathy o Post-Operative • Hemangioma Less Common • Rheumatoid Arthritis • Ankylosing Spondylitis • Hemodialysis Spondyloarthropathy Rare but Important • Gout

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Degenerative Endplate Changes o Type I: • Tl, t T2; present in 4% of patients undergoing MR for disc disease o Type II: t Tl; present in 16% of patients undergoing MR for disc disease

Type III: • Tl, • T2; least common, approximately 1% o Other signs of disc degeneration o No associated soft tissue mass • Schmorl Node o Intravertebral disc herniation o Well-corticated margins o May show t T2 signal if acute • Pyogenic Osteomyelitis o Ill-defined hypointense vertebral marrow on Tl WI with loss of end plate definition on both sides of the disc o Paraspinal ± epidural infiltrative soft tissue ± loculated fluid collection • Wedge Compression Fracture o Depression of vertebral end plate, usually superior only o t STIRsignal intensity, band-like or triangular configuration if acute o

Alternative Differential Approaches • Bright Tl signal (fatty endplate) change vs. low Tl signal • Bright Tl signal o Type II degenerative endplate change o Chronic Schmorl node o Chronic compression fracture o Healed osteomyelitis (fatty marrow conversion) o Hemangioma or focal fatty marrow • Low Tl signal o Everything else!

II 4 16

Sagilta! T2W! MR shows degenerative type I endp!ate changes at multiple levels as linear bands of T2 hyperintensity adjacent to degenerated discs

=.

Sagittal T1 C+ FS MR is remarkable for pronounced type I endpJale enhancement and fine, linear enhancement of the intervertebral disc. No endplale

irregularity or paravertebral mass suggests infection.

VERTEBRAL

ENDPlATE

SIGNAL

ABNORMALITY

Schmorl Node (Left) Sagillal TI C+ FS MR shows inFerior endplace L 1 Schmorl node, wilh adjacent type I degenerative endplale enhancement 81. (Right) Sagillal T2WI MR shows irregular T2 hyperinlensity from the intervertebral

o (J) ()

disc

=::I

region with epidural phlegmon and bone dislOrling the ventrallhecal sac.

Wedge Compression

Fracture (Left) Sagillal STIR MR shows horizontal band-like appearance of multiple acule compression

fractures

=-

indicating underlying benign etiology such as trauma or oSleopenia. (Right) Sagillal TI WI MR show the anlerior fusion over multiple

segments with fal signal and irregular

chronic

1::1

fracture

as a pseudoarthrosis 81. site functioning

(Left) Sagillal T2WI MR shows palchy amorphous T2 hyperintense material replacing intervertebral disc and eroding adjacent endplales =::I. (Right) Sagillal T I WI MR shows multilevel well-defined endplale erosions and low Tl signal I:D. Severa/lesions have a "punched

out" appearance,

typical for gout.

II 4 17

SECTION 5 Extradural Anatomically Based Differentials Epidural Mass, Spine Ventral/Lateral Paraspinal

11-5-2 11-5-8

Mass

Generic Imaging Patterns Paraspinal Extradural Extradural Extradural

Modality-Specific Soft Tissue Extradural, ExtraduraC Extradural Extradural Extradural Extradural

11-5-10 11-5-12 11-5-14 11-5-16

Muscle Abnormality Lesions, Multiple Lesion, No Enhancement Lesion, Solid Enhancement

Imaging Findings

Calcification, Paraspinal Normal Marrow Signal Abnormal Marrow Signal Lesion, T1 Hyperintense Lesion, T1 Hypointense Lesion, T2 Hyperintense, Tl Isointense Lesion, T2 Hypointense, T1 Hypointense

11-5-20 11-5-22 11-5-26 11-5-30 11-5-32 11-5-36 11-5-40

Clinically Based Differentials Lumbar Soft Tissue Mass, Pediatric

11-5-42

EPIDURAL

MASS, SPINE

Common • Intervertebral Disc Herniation • Facet Arthropathy • Hypertrophied Ligamentum Flavum • Epidural Lipomatosis • Synovial Cyst • Epidural Fluid Collections a Pseudomeningocele a Hematoma a Abscess • Epidural Metastatic Disease • Neurofibroma • Schwannoma • Arachnoid Cyst • OPLL Rare but Important • Tumoral Calcinosis • Primary Bone Tumor a Hemangioma a Plasmacytoma a Osteoblastoma a Aneurysmal Bone Cyst a Lymphoma a Leukemia a Chordoma a Chondrosarcoma a Giant Cell Tumor a Ewing Sarcoma a Osteosarcoma • Extramedullary Hematopoiesis • Angiolipoma

•

•

•

•

•

ESSENTIAL INFORMATION

II 5 2

Helpful Clues for Common Diagnoses • Intervertebral Disc Herniation a Most common epidural mass a Virtually always ventral or ventrolateral to the thecal sac a May have thin rim of enhancement, especially if recurrent/post-operative • Facet Arthropathy a Joint space narrowing, osteophyte formation, effusion a Often accompanied by ligamentous hypertrophy a May be asymmetric • Hypertrophied Ligamentum Flavum

Abnormal thickened ligamentum flavum, may calcify a Often associated with degenerative facet arthropathy Epidural Lipomatosis a Prominent epidural fat, can be seen with prolonged steroid administration or Cushing syndrome a Affects distal thoracic and lumbar spine a Key finding is mass effect on the thecal sac • "Y"shaped or trefoil configuration of thecal sac on axial images Synovial Cyst a Sign of facet degeneration a Circumscribed, fluid-filled structure a Adjacent/contiguous with a facet joint a Cyst along ventral facet may impinge on thecal sac or nerve root Pseudomeningocele a Epidural fluid collection a Surgical or traumatic dural defect causing a CSF leak a Margins may enhance if located within a surgical bed Hematoma a May be spontaneous or associated with trauma or instrumentation a Signal varies with the age of the hemorrhage a Mild or no enhancement Abscess a May be associated with disc space infection or instrumentation/inoculation a Marked peripheral enhancement typical, contents typically approximate fluid signal on Tl/T2 Epidural Metastatic Disease a Enhancing soft tissue mass, may be multiple a Most often associated with epidural extension from a vertebral metastasis a May also occur with transforaminal spread from a paraspinal or posterior mediastinal tumor Neurofibroma a Enhancing nodular, fusiform, or dumbbell mass associated with a nerve root a Epidural neurofibroma typically intraforaminal or transforaminal a

DIFFERENTIAL DIAGNOSIS

•

•

EPIDURAL May be associated with vertebral scalloping, thinning/remodeling of pedicles '. o Most (90%) solitary, non-syndromlC o May be multiple, extensive; associated with plexiform neurofibromas (neurofibromatosis type 1) • Schwannoma o Enhancing nodular, fusiform, or dumbbell mass associated with a nerve root o Most schwannoma intradural in location; epidural schwannoma typically intraforaminal or transforaminal o Not reliably distinguished from solitary neurofibroma • Arachnoid Cyst o Thin walled, nonenhancing o Contents follow CSF o May be associated with vertebral scalloping, thinning/remodeling of pedicles • OPLL o Thickened, calcified posterior longitudinal ligament o Ventral to thecal sac, may cause significant canal stenosis o Cervical involvement more frequent than thoracic o Best appreciated with CT o Most often hypo intense on Tl/T2WI o Center may become Tl/T2 hyperintense if a marrow space develops within the ossified ligament o

Intervertebral

MASS, SPINE Helpful Clues for Rare Diagnoses • Tumoral Calcinosis o Lobulated, calcific mass with surrounding the facet joint o May see bone remodeling, no destruction • Hemangioma o Extraosseous component of an "aggressive" vertebral hemangioma more frequently hypo intense on Tl WI • Lymphoma o Enhancing epidural mass or epidural extension from a vertebral lesion o Spinal lymphoma may also manifest with leptomeningeal or intramedullary lesions • Leukemia o Granulocytic sarcoma (chloroma) • Solid mass composed of leukemic cells outside of the bone marrow • In the CNS, usually epidural; distinct from leukemic meningitis (subarachnoid) • Extramedullary Hematopoiesis o Paravertebral and epidural lobulated masses o Thoracic paraspinallocation most common o Associated with severe harrow hyperplasia due to chronic anemia • Angiolipoma o Epidural mass with mixed fat and soft tissue components

Disc Herniation

=

Axial T2WI MR shows a sequestered disc fragment in the left anterolateral epidural space at the L4 level impinging on the left L4 nerve root.

=

Axial T2WI MR shows bilateral facet hypertrophy effacing the thecal sac posterolaterally and contribuUng to moderate canal stenosis.

II 5 3

EPIDURAL

MASS, SPINE

Epidural Lipomatosis (Left) Sagittal T1 WI MR shows severe central canal stenosis at L4-5 due to extensive posterior ligamentous hypeftrophy 1:::1 effacing the thecal sac dorsally. Note also disc space narrowing and mild degenerative anterolisthesis E.:J at this level. (Right) Axial T1WI MR shows the typical appearance

of prominent

epidural fat compressing the thecal sac, causing a Y" or trefoil appearance of the thecal sac 1:::1. fI

Synovial Cyst

Pseudomeningocele

(Left) Axial T2WI MR shows a circumscribed, ring· shaped lesion ~ arising from the ventral aspect of the right L4-5 lumbar facet resulting in moderate canal stenosis. (Right) Sagittal FSEIRshows a large fluid collection at L4-5 laminectomy site extending from the epidural

space into the subcutaneous £issues. Resulting mass effect and small disc herniation 1:::1 significanlly effaces the thecal sac 8>,

Abscess (Left) Sagittal T1WI MR shows a subdural hematoma in the thoracic spine both ventral 1:::1 and dorsal !:±I to the thecal sac. (Right) Sagittal T1 C + M R shows a large ventral epidural collection margins

with enhancing

II] extending

from

C2 into the upper thoracIc spine, causing canal narrowing

and significant

cord compression.

II 5 4

EPIDURAL

Epidural Metastatic

Disease

MASS, SPINE

Neurofibroma (Lefl) Axial T1 WI MR shows

a primary lung neoplasm invading the chest wall and paraspinous tissues, extending through the neural foramen into the epidural space with mild thecal sac effacement. (RighI) Axial T2* GRE MR shows a cylindricallransforaminal mass of the cervical spine.

=

The intraspinal epidural component causes severe canal stenosis and cord compression ~.

Schwan noma

Arachnoid

Cyst (Lefl) Axial CrCT shows a

I'dumbbell" schwannoma with lransforaminaJ

mass and

associated bony remodeling. The intraspinal component has mild mass effect on the thecal sac ffi (Righi) Sagittal T2WI MR shows a circumscribed, CSF-signal extradural mass with widening of the canal, containing two foci of flow artifact=.

(Lefl) Axial bone CT shows marked ossification of the cervical posterior longitudinal ligament ~ causing severe canal stenosis. (RighI) Axial bone CT shows tumoral calcinosis, with an exuberant calcific mass involving dorsal elements of the lumbar spine

=

II 5 5

EPIDURAL

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MASS, SPINE

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Plasmacytoma (Lefl) Axial T2WI MR shows an aggressive vertebral hemangioma

involving

the

neural arch with marked extension into the epidural space contributing to severe canal stenosis. (RighI) Sagittal T1 WI MR shows an upper thoracic compression fracture with ventral epidural extension 1:1] causing canal stenosis and cord compression.

Osteoblastoma

Aneurysmal

Bone Cyst

(Lefl) Axial T2WI MR in a patient with a painful scoliosis shows an expansile mass arising from the right L2 lamina. The dorsal epidural component mildly effaces the poslerolalcralthecal sac ~. (RighI) Axial T2WI MR shows a multiloculated, expansile mass containing multiple fluid-fluid levels associated with the dorsal elements.

Chondrosarcoma (Lefl) Sagittal T1 C+ MR shows an enhancing, infiltrative,

circumferential

epidural mass B>' with multiple vertebral body involvement 1:1] in this patient with lymphoma. (RighI) Axial T1 C+ MR shows a large, aggressive-looking thoracic vertebral body mass with peripheral enhancement and epidural extension ~.

II 5 6

EPIDURAL

en

MASS, SPINE

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Giant Cell Tumor

a.

Giant Cell Tumor (Left) Axial CECT shows lytic, hetefOgeneously enhancing vertebral body mass, extending into the right pedicle with right lateral =:I and epidural

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exlra05seOU5 extension.

(Right) Axial TI C+ MR shows a large enhancing mass in the cervical epidural space, compressing the cord at the C2-] level and extending into the left paravertebral region thfOugh an enlarged left neural foramen =:I.

Ewing Sarcoma

Osteosarcoma (Left) Axial T2WI MR shows a thoracic vertebral body lesion with a large exlraosseous component filling the left hemithorax 811 and extending into the epidural space PJ::l. (Rigllt) Axial T1 C+ FS MR shows a permeative L3 lesion with

extraosseous extension into the epidural paravertebral

=:I and 3>

spaces.

(Left) Sagittal T1 WI MR shows extramedullary

hematopoiesis

presenting as

a dorsal epidural soft tissue

mass

=.. causing canal

stenosis and cord compression. (Right) Sagittal T1WI MR shows a large dorsal epidural heterogeneously hyperintense mass

causing canal stenosis and cord compression.

II 5 7

VENTRAL/LATERAL

DIFFERENTIAL DIAGNOSIS Common • Lymphadenopathy o Lymphoma o Metastases • Metastases, Vertebral Body • Aortic Aneurysm • Paras pinal Abscess • Retroperitoneal Hemorrhage • Meningocele, Lateral • Neurogenic Tumor o Schwannoma o Neuroblastoma o Ganglioneuroma Less Common • Extramedullary Hematopoiesis • Retroperitoneal Lymphocele • Retroperitoneal Fibrosis • Liposarcoma, Soft Tissue • Fibrosarcoma, Soft Tissue

PARASPINAL MASS

Testicular germ cell tumors: Nodes at level of ipsilateral renal hilum o Metastases • Vertebral body involvement with sparing of disc space, with adjacent soft tissue extension • Aortic Aneurysm o Dilatation of the aorta (Ao) ~ l.Sx the normal diameter (S cm ascending Ao, 4 cm arch/thoracic Ao, 3 cm distal abdominal o

Ao)

Always measure Ao outer-to-outer borders Symptoms: Chest, back, or abdominal pain, distal embolization Paras pinal Abscess o Look for associated disc space infection o Central necrotic foci without enhancement Retroperitoneal Hemorrhage o High density collection in retroperitoneal space with fluid-fluid level o Causes include anticoagulation, aneurysm, & tumor rupture Meningocele, Lateral o CSF signal/density meningeal protrusion through neural foramen into adjacent intercostal/extrapleural space o Strong association with NFl Neurogenic Tumor o Schwannoma: Well-circumscribed, "dumbbell"-shaped, enhancing spinal mass centered about foramen o

o

•

•

ESSENTIAL INFORMATION

•

Helpful Clues for Common Diagnoses • Lymphadenopathy o Lymphatic or hematogenous spread • Testicular, ovarian cancer • Melanoma • Prostate, lung, breast o Direct extension from primary intra-abdominal neoplasms: Pancreas, GI cancers

•

lymphadenopathy

II 5 8

Axial CEer shows a melastatic germ cell tumor as a large confluent/ow density retroperitoneal mass 81 that displaces the aorla anteriorly.

Metastases

Axial T1WI MR shows a mass invading the left lateral lhoracic vertebral body, left posterior elements, & neural foramen Epidural extension effaces the thecal sac but does not compress the cord.

=.

VENTRAL/LATERAL PARASPINAL MASS

Aortic Aneurysm

Paraspinal Abscess (Left) Axial CECT shows retroperitoneal (ibrosis ~ surrounding an abdominal aortic aneurysm, also called "perianeurysmal Fibrosislr. This is believed to result from immunologic response to atheromatous plaque. (Right) Axial CECT shows a brucellosis abscess as a well-defined, non enhancing foci involving both psoas muscles and the prevertebral space.

=

Paraspinal Abscess

Meningocele,

Lateral (Left) Sagittal T2WI MR shows thoracic spinal TB in a young child with kyphotic deformity and large epidural and paraspinal abscesses ~. (Right) Axial T2WI MR shows one appearance of lateral meningocele associaled with Nf I. T2 image shows dural ectasia involving midthoracic thecal sac ~ with right lateral meningocele 81 projecting into the paraspinal region.

Schwan noma

Extramedullary

Hematopoiesis (Left) Axial TI C+ MR shows well-defined enhancing mass ~ within the neural foramen with inlralumOral cysts typical of schwannoma. (Right) Axial T2WI MR shows a lypical appearance o( extramedullary

hematopoiesis

presenting as

bilateral paraspinal masses ~. All marrow signal will be abnormal.

II 5 9

PARASPINAl MUSClE ABNORMALITY

DIFFERENTIAL DIAGNOSIS Common • Traumatic Spinal Muscle Injury • Muscle Denervation • Pseudomeningocele • Paraspinal Abscess • Tumor, Benign o Lipoma, Soft Tissue o Hemangioma, Soft Tissue o Neurofibroma o Schwannoma less Common • Tumor, Malignant o Metastasis o Fibrosarcoma, Soft Tissue o Malignant Fibrous Histiocytoma o Neuroblastic Tumor o MPNST • Rhabdomyolysis

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Traumatic Spinal Muscle Injury o Muscle T2 hyperintensity related to traumatic contusion, laceration, hematoma o Muscle may still be functional, even with severe injury • Muscle Denervation o Asymmetric muscle volume loss with fatty replacement ~ chronic denervation o Acute denervation may show enlargement Traumatic Spinal Muscle Injury

II 5 10

Axial CECT shows a righl L3 transverse process fraclure

~ and extensive hematoma involving the right psoas muscle and fXJ5lerior paraspinous muscles.

• Pseudo meningocele o Spinal cyst contiguous with thecal sac, not lined with meninges o CSF-filled spinal axis cyst with supportive post-operative or post-traumatic ancillary findings • Paraspinal Abscess o Paravertebral enhancing phlegmon or peri pherally enhancing lig uified collection o Ill-defined infiltrative paraspinal soft tissue o Obliterated soft tissue fascial plane o Low density or t T2 intramuscular collection • Tumor, Benign o Well-defined soft tissue enhancing lesion o Neurofibroma, schwannoma at foramen Helpful Clues for less Common Diagnoses • Tumor, Malignant o Enlarging, heterogeneous, soft tissue mass o Look for adjacent bone destruction o Any patient with spontaneous musculoskeletal hemorrhage should be evaluated for underlying MFH • Rhabdomyolysis o Clinical and biochemical syndrome resulting from damage of integrity of skeletal muscle, with release of toxic muscle cell components into circulation o Elevated serum creatine kinase (CK) 5x normal value, 100% sensitive o Increased T2 signal within affected skeletal muscle group

Traumatic Spinal Muscle Injury

Posl-myelogram CT shows mulliple foci of calcificalion within the dorsa! paraspinal muscles 1::1 after inlerbody fusion and posterior instrumentation related to operative

trauma and subsequent myositis ossificans.

PARASPINAL

Muscle Denervation

MUSCLE ABNORMALITY

Pseudo meningocele (Left) Axial T1WI MR in patient with Chiar; 2 shows lumbosacral dysraphism and repaired myelomeningocele changes as well as striking replacement of the paraspinal muscles with fat, an extreme end result of severe chronic denervalion. (Right) Axial T1WI MR shows large dorsal soft tissue pseudomeningocele SlI following multilevel lumbar laminectomy and fusion. There are bone graft fragments within the fluid collection=.

Paraspinal

Abscess

Neurofibroma (Left) Axial NECT shows extensive destructive coccidiomycosis involving the lumbar spine. Large paravertebral and dorsal

paraspinal

Ee:I

=

abscesses are

present with vertebral body lysis. (Right) Axial T2WI FS MR shows a typical appearance of large neurofibromas in a patient with NFl

involving

the upper

thoracic spine with large exlraForaminaJ

component

SlI.

Metastasis

Rhabdomyolysis (Left) Axial T1 WI MR shows renal cell metastasis involving the right thoracic rib with extension into the adjacent musculature. There is sligh I righllaleral epidural eXlension (Right) Axial T2WI MR shows diffuse hyperintensity from right paraspinal muscles, sparing the psoas muscle in this ca,e of post-operative rhabdomyolysis.

=.

=

II 5 11

EXTRADURAL

DIFFERENTIAL DIAGNOSIS Common • Multiple Disc Herniations • Facet Arthropathy • Hypertrophied Ligamentum • Epidural Fluid Collections o Hematoma o Abscess • OPLL • Epidural Metastases • Plasmacytoma • Neurofibromatosis Type 1

Flavum

Rare but Important • Extramedullary Hematopoiesis • Multiple Epidural Hemangioma

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Multiple Disc Herniations o Disc herniations are most common ventral epidural mass in the spine o May have a thin rim of enhancement, especially if recurrent/post-operative • Facet Arthropathy o Most often associated with disc degeneration at that level o Thinning of articular cartilage, osteophyte formation o Often accompanied by ligamentous hypertrophy o "Blocky" facet morphology may be normal variant, not degenerative Multiple

II 5 12

LESIONS,

MUlTIPLE

• Hypertrophied Ligamentum Flavum o Similar to facet arthropathy, often at a level with disc degeneration; may be a response to altered loading or instability o Posterolateral effacement of epidural fat and thecal sac • Hematoma o Post-traumatic, coagulopathic, or post-surgical etiology o Signal varies with age of hemorrhage o Mild or no peripheral enhancement • Abscess o May be associated with disc space infection or instrumentation/inoculation o Marked peripheral enhancement typical • OPLL o Thickened, calcified posterior longitudinal ligament o Ventral to thecal sac, may cause significant canal stenosis o Cervical involvement more frequent than thoracic o Best appreciated with CT • Epidural Metastases o Enhancing soft tissue mass, may be multiple o Most often due to epidural extension of a vertebral metastasis, primary epidural metastases also occur o May also occur with transforaminal spread from a paras pinal or posterior mediastinal tumor

Disc Herniations

Sagittal T2WI MR shows multiple large lower thoracic disc herniations, which efface the thecal sac and compress the cord at multiple levels ClI.

=

Sagittal T2WI MR shows multiple levels of hypertrophic, ossified ligamentum {fayum, some labeled with effacing the thecal saCfJOsterolaterally.

EXTRADURAL

lESIONS,

MULTIPLE

Abscess (Left) SagiHal TI WI MR shows a spontaneous epidural hematoma presenting with two ventral lentiform-shaped epidural hematomas =:I effacing the thecal sac & compressing the spinal cord. Note the appearance of normal dorsal epidural fat 0:> .. (Right) Sagittal TI C+ MR shows a multiloculated, dorsal epidural abscess which compresses cord ventrally over a long segment. Metal/ic artifact =:I is due 10 recently placed spinal fusion hardware.

a

(Left) Sagittal T2WI MR shows multiple foci of posterior ligament ossification with resulting canal stenosis and cord compression E!:1 (Right) SagiHal T2WI MR in a patient with metastatic thymic carcinoma shows diffuse

=

vertebral metastases. In several locations, epidural extension results in thecal sac effacement, canal stenosis, and cord compression.

=

Neurofibromatosis

Type 1

Extramedullary

Hematopoiesis (Leh) Sagillal TI WI MR shows intraspinal extension of neurofibromas at two levels causing canal stenosis and cord compression. (Right) SagiHal T2WI MR shows diffusely hypointense ,narrow and nodular masses in the ventral epidural space of the sacral canal in this patient with thalassemia.

=-

=

II 5 13

EXTRADURAL

LESION,

DIFFERENTIAL DIAGNOSIS Common • Nonbony o Stenosis, Acquired Spinal, Lumbar o Facet Joint Synovial Cyst o Hematoma, Epidural-Subdural o Sequestered Disc Fragment o Perineural Root Sleeve Cyst o Pseudomeningocele o Arachnoid Cyst o Lipoma, Spinal o Epidural Lipomatosis o Metal Artifact • Bony o Limbus Vertebra o Schmorl Node o Bone Island o Degenerative Endplate Changes (Type Ill) o OPLL o Ossification Ligamentum Flavum o Post Irradiation Vertebral Marrow o Myelofibrosis o Partial Vertebral Duplication o Diastematomyelia Less Common • Osteochondroma • Dorsal Dermal Sinus

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Enhancement may be difficult to see against fatty bone marrow unless fat saturation used Stenosis, Acquired

II 5 14

Spinal, Lumbar

Sagittal T2WI MR shows severe facet osteoarthritis, with large bone spur 1:2 and associated redundancy of ligamentum

flavum

occasionally

enhance.

causing spinal stenosis. Osteophyles

NO ENHANCEMENT Post-contrast MR should include at least 1 sequence using fat saturation • Nonenhancing extradural masses can often be distinguished by location o Sequestered disc anterior to thecal sac o Facet joint cyst adjacent to arthritic facet joint o Perineural cyst in neural foramen or lateral o Hematoma often mimics disc o

Helpful Clues for Common Diagnoses • Some lesions will enhance when acute/active but not in chronic stages o Hematoma o Post-operative scar after discectomy enhances for 12-18 months o Schmorl node o Degenerative endplate changes o Acute disc sometimes shows peripheral enhancement due to inflammatory tissue • All spinal bone tumors enhance except osteochondroma, bone island • Facet joint cyst can be followed to arthritic facet joint • Pseudomeningocele vs. abscess o Pseudomeningocele: Homogeneous fluid with thin rim of enhancement o Abscess: Heterogeneous fluid, thick, irregular rim of enhancement Helpful Clues for Less Common Diagnoses • Osteochondroma: Marrow continuity between vertebra and exostosis o Cartilage cap seen in childhood, tends to regress in adulthood

Facet Joint Synovial Cyst

Sagittal TI C + MR shows a large facet cyst 81. Enhancement of cyst capsule, as seen here, is common.

EXTRADURAL

lESION,

NO ENHANCEMENT

Pseudomeningocele (Left) sagiual T2WI MR shows a sequestered disc 8::1 posterior to 51 vertebra. Hematoma may have the same appearance, probably accounting for many cases of "spontaneously resolving" disc herniation. (Right) sagiual T1 C+ MR shows a large, nonenhancing fluid collection following spinal surgery. It can usually be distinguished from an abscess by smoolh walls and a thin rim of enhancement reflecting an adjacent

=

reactive

Degenerative Epidural Lipomatosis

change.

Endplate Changes (Type

III) (Left) sagiu<11T2WI MR shows extensive fat in the spinal canal, narrowing the thecal sac. Lipomatosis, like all fat, shows minimal enhancement with gadolinium. (RighI) Sagittal T1 WI MR shows low signal intensity adjacent to the L5-s/ disc reflecting reactive bony sclerosis; this pattern wUf not enhance with gadolinium, although earlier phases of degenerative change often

=-

enhance,

reflecting

hyperemia.

Osteochondroma (Leh) Sagittal T1 C+ MR shows a low signal intensity throughout the spine, nonenhancing.

The vertebral

venous plexus does show normal enhancement. (Right) sagiual STIR MR shows a bony projection from the C4 vertebra The continuity of bone marrow between the vertebral body and the exostosis is indicative of

=.

osteochondroma.

II 5 15

ro ~ :J

EXTRADURAL

LESION, SOLID ENHANCEMENT

"0

ro ~ X

w Q)

r::

'50

en

DIFFERENTIAL DIAGNOSIS Common • Peridural Fibrosis • Metastases, Blastic Osseous • Metastases, Lytic Osseous • Neurofibroma • Schwannoma • Lymphoma • Plasmacytoma Less Common • Venous Vascular Malformation • Neuroblastic Tumor • Ewing Sarcoma • Hemangioma Rare but Important • Langerhans Cell Histiocytosis • Extramedullary Hematopoiesis • Osteosarcoma • Hemangiopericytoma • Angiolipoma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Use all known clinical information as clues to help narrow the differential possibilities Helpful Clues for Common Diagnoses • Peridural Fibrosis a Epidural scar formation after lumbar spinal surgery a Infiltration of epidural/perineural fat by enhancing soft tissue density (intensity) in correct clinical context • Metastases, Blastic Osseous a Bone production> bone destruction a Destroys posterior vertebral body cortex first - pedicle a Hypointensity reflects blastic changes • Metastases, Lytic Osseous a Bone destruction> bone production a Destroys posterior vertebral body cortex first - pedicle a Lesions diffusely enhance (may mask lesions if no fat suppression used) • Neurofibroma a Variable involvement of spinal root, neural plexus, peripheral nerve, or end organs

II 5 16

Plexiform neurofibromas are pathognomonic of NFl, often affect sacral or brachial plexus • Schwannoma a Neoplasm of Schwann cell investiture of spinal and peripheral nerves a Peripheral origin pushing adjacent axons rather than infiltration within distinguishes from neurofibroma a Consider neurofibromatosis type 2 if many tumors are identified • Lymphoma a Lymphoreticular neoplasms with wide variety of specific diseases & cellular differentiation a Multiple types with protean imaging manifestations • Plasmacytoma a Solitary monoclonal plasma cell tumor of bone or soft tissue a Often without specific features to distinguish from solitary hematogenous metastasis a

Helpful Clues for Less Common Diagnoses • Venous Vascular Malformation a Congenital transpatial vascular malformation of venous channels present from birth a Mass-like, frequently enhances moderately (less than soft tissue hemangioma) a No arterial vessels within lesion a Venous channels may be large; look for phleboliths to make specific diagnosis • Neuroblastic Tumor a Neuroblastic tumors = ganglioneuroma, ganglioneuroblastoma, and neuroblastoma a Abdominal (40% adrenal, 25% paraspinal ganglia) > thoracic (15%) > pelvic (5%) > cervical (3%); miscellaneous (12%) a Identification of intraspinal spread has important treatment and prognostic implications • MR is more sensitive than CT for detecting intraspinal spread • Ewing Sarcoma a Usually adolescents, younger adults a Permeative cellular lytic lesion of vertebral body or sacrum a Involve vertebral body, ribs, ilium before neural arch • Hemangioma

EXTRADURAL lESION, SOLID ENHANCEMENT o

o

Typical "benign" (fatty stroma) hemangioma hyperintense on Tl WI and T2WI MR + contrast enhancement "Aggressive" hemangioma iso- to hypointense on Tl WI and hyperintense on T2WI MR + avid contrast enhancement • Lesion growth, bone destruction, vertebral collapse, absence of lesion fat, active vascular component • Pathologic fracture or epidural extension is common - cord compression

Helpful Clues for Rare Diagnoses • Langerhans Cell Histiocytosis o Abnormal histiocyte proliferation granulomatous skeletal lesions o Thoracic (54%) > lumbar (35%) > cervical (11%)

Most frequent imaging appearances • Vertebra plana sparing disc space • Destructive lesion with soft tissue component resembling other epidural spinal tumors o Use location and patient age to suggest diagnosis • Extramedullary Hematopoiesis o Epidural ± paravertebral proliferation of hematopoietic tissue rests in response to profound chronic anemic state o Enhancing isointense thoracic intra- or paraspinal masses with associated diffuse marrow hypointensity o Mid-thoracic> cervical, lumbar • Osteosarcoma o

Peridural

Fibrosis

T1 C+ MR demonstrates extensive enhancing epidural fibrosis circumferenlially surrounding the thecal sac Note metal artifact from intervertebral fusion cages 8:1.

Axial

=.

Wide zone of transition, permeative appearance, cortical breakthrough, and soft tissue mass o 80% have bone matrix visible on radiographs and CT • Osteoid matrix produced directly by malignant cells o Majority arise in posterior elements • Hemangiopericytoma o Hypervascular neoplasm arising from pericytes o Avidly enhancing mass with large soft tissue component expanding/eroding spinal canal • Angiolipoma o Benign tumor with adipose and vascular elements o Hyperintense mass on unenhanced Tl WI, enhancement on fat-suppressed Tl WI o Focal or infiltrating forms • Infiltrating more common in anterior epidural space, may destroy adjacent bone • Focal more common in posterior thoracic epidural space, no bone destruction o No vascular flow voids o

Metastases,

Sagiltal T1

c+

Blastic Osseous

MR shows abnormal enhancement of

multiple vertebral breast carcinoma metastases. CT

II 5

imaging (not shown) confirmed blastic appearance.

17

EXTRADURAL LESION, SOLID ENHANCEMENT

Metastases,

lytic Osseous

Neurofibroma

(Left) Sagittal T7 C+ MR demonstrates abnormal enhancement of lytic renal cell carcinoma metastasis The diagnosis was confirmed with bone CT (not shown). (Right) Axial T7 C+ MR reveals a large right lumbar epidural and paraspinal neuroFibroma in a patient with confirmed neurofibromatosis lype ,.

=.

=

Schwannoma (Left) Axial T7 C+ MR depicts a large right cervicothoracic

schwannoma with dumbbell intradural and extradural components. Note spinal

cord I:] compression. (Right) Sagittal T7 C+ MR reveals enhancing epidural tumor extension of Ilodgkin lymphoma, producing spinal cord compression.

-=

Plasmacytoma (Left) Axial T7 C+ MR shows extensive

enhancing

epidural

tumor displacing the spinal cord. There is also marrow infiltration

into the transverse

processes

and adjacent

"Drape"

configuration

ventra/wmor confirms

rib. of the

extension

epidural

localization. (Right) Axial T7 C+ FS MR demonstrates a paraspinal enhancing neuroblastoma with epidural extension through the ipsilateral

neural foramen,

displacing the dural sac.

II 5 18

Neuroblastic

Tumor

EXTRADURAL

Ewing Sarcoma

lESION,

SOLID ENHANCEMENT

Hemangioma (Left) Axial T7 C+ MR reveals a huge paraspinal Ewing sarcoma that arises from the ipsilateral posterior rib with epidural

extension,

producing spinal cord compression. (Right) Sagiltal T7 C+ MR depicts an

aggressive vertebral hemangioma associated with pathological compression fracture, producing a large epidural mass and thecal sac

compression.

Extramedullary

Hematopoiesis (Left) Sagittal T7 C+ FS MR

demonstrates

complete

collapse of the T /2 vertebral body (vertebra plana). The vertebral body and the adjacent 50ft tissues reveal

marked enhancement following gadolinium administralion. (Right) Sagittal T7 C+ MR depicts an elongated ovoid

well-circumscribed epidural soft tissue mass with diffuse

and intense enhancement compressing the distal thoracic spinal cord.

(Left) Axial T7 C+ MR shows

a large lobulated enhancing mass in left paravertebral

soft

tissues and osseous posterior elements El extending along the dural margin into the ipsilateral

neural foramen

=. (Right) Sagiltal T7

C+ FS

a farge dorsal intensely enhancing epidural mass in the upper thoracic spine, producing spinal cord compression. MR demonstrates

II 5 19

SOFT TISSUE CALCIFICATION, PARASPINAL

Common • Heterotopic Ossification o DISH o Spinal Muscle Injury, Traumatic o Post-Operative Change, Normal o Neurogenic (Charcot) Arthropathy • Calcification o Calcific Tendinitis, Longus Coli o Osteomyelitis, Granulomatous Less Common • Heterotopic Ossification o Spondyloarthropathy, Seronegative o Osteosarcoma • Calcification o Schwannoma o Polymyositis/Dermatomyositis o Spondyloarthropathy, Hemodialysis o Juvenile Idiopathic Arthritis Rare but Important • Fibrodysplasia Ossificans Progressiva (FOP)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Heterotopic ossification: General term meaning bone forming outside normal sites o Myositis ossificans: Heterotopic ossification forming in muscles o Causes: Trauma, surgery; paraplegia Helpful Clues for Common • Heterotopic Ossification

Over time, forms cortex and internal trabeculae • In osteosarcoma, structure lacking o DISH, seronegative spondyloarthropathy: Ossification of paraspinous ligaments follows ligament contour o Charcot arthropathy: Combination of florid periosteal new bone and small bone fragments in soft tissues • Usually more exuberant and disorganized than post-traumatic heterotopic ossification • "5 Ds" of Charcot joint: Preserved or increased density, bone debris, destruction, joint distention, joint dislocation • Calcification o Calcific tendinopathy of longus coli: Linear calcification associated with longus coli muscle edema, often fluid collection o Hydroxyapatite, gout, or scleroderma: Amorphous or globular o Calcium pyrophosphate deposition disease: Linear o Granulomatous infection: Irregularly shaped, associated with abscess o Polymyositis: Fine, reticular pattern along fascial planes o

DIFFERENTIAL DIAGNOSIS

Diagnoses

Helpful Clues for Less Common Diagnoses • Juvenile Idiopathic Arthritis o Periosteal new bone or ligament ossification

DISH

Heterotopic Ossification

II 5 20

=

Coronal bone CT shows post-traumatic ossification in paraspinous fat. Mature bone architecture distinguishes it from osteosarcoma.

=.

Sagittal bone CT shows unusually bulky ossification of anterior longitudinal ligament This degree of ossification

may cause dysphagia.

SOFT TISSUE CALCIFICATION,

Calcific Tendinitis,

PARASPINAL

Longus Coli (Left) Anteroposterior radiograph shows florid, paraspinous, periosteal new bone ~ bone sclerosis, bone debris, disorganization,

and bone destruction, all hallmarks of Charcot arthropathy. (RighI) Axial CECT shows calcification in the longus coli muscle. Muscle is Jaw attenuation and enlarged.

Osteomyelitis,

Granulomatous

Spondyloarthropathy,

=

Seronegative (Lefl) Axial NECT shows vertebral body erosions and a low attenuation paraspinous 81 and spinal canal mass !:;J. Note the calcifications Itl; this combination usually indicates TB. (RighI) Anteroposterior radiograph shows slender ossification of the paraspinou5 ligaments Sacroiliac joint fusion m is key to diagnosis.

=.

Osteosarcoma

Juvenile Idiopathic

Arthritis (Left) Axial bone CT shows a mass containing

immature

ossification and involving ilium, sacrum,

sacroiliac

joint, and sort tissues. Although the density of osteosarcoma varies, its appearance is always aggressive. (RighI) Sagittal bone CT shows heterotopic ossification related to long-standing atlantoaxial subluxation in jlA. Periosteal new bone ~ is a more

=

common

finding.

II 5 21

EXTRADURAL, NORMAL MARROW SIGNAL

ell

~ ::J

""0

ell ~ X

W

Gl

l:

a. m

Common • Disc Herniation o Intervertebral Disc Herniation, Cervical o Intervertebral Disc Herniation, Thoracic o Intervertebral Disc Herniation, Lumbar o Intervertebral Disc Extrusion, Foraminal • Osseous Degenerative Disease o Intervertebral Disc Bulge o Facet Mthropathy, Cervical o Facet Arthropathy, Lumbar o Facet Joint Synovial Cyst • Infection o Abscess, Epidural o Abscess, Paraspinal • Trauma o Hematoma, Epidural-Subdural o Hematoma, Spontaneous Epidural o Hematoma, Paraspinal • Neoplasm o Neuroblastic Tumor o Lymphoma o Schwan noma o Neurofibroma • Ligamentous Ossification o OPLL o DISH o Ossification Ligamentum Flavum • Ligamentous Hypertrophy • Peridural Fibrosis • Perineural Root Sleeve Cyst Less Common • Epidural Lipomatosis • Teratoma, Sacrococcygeal

•

•

•

Rare but Important • Neurenteric Cyst

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Clinical context helps narrow differential list

II 5 22

Helpful Clues for Common Diagnoses • Disc Herniation o Intervertebral Disc Herniation, Cervical • Localized displacement of disc material beyond vertebral ring apophyses o Intervertebral Disc Herniation, Thoracic • T6 - T11 most common, rare in upper thoracic spine

Intervertebral Disc Herniation, Lumbar • Most common at L4-5, L5-S1 o Intervertebral Disc Herniation, Foraminal • Soft tissue mass contiguous with parent disc - extruded disc material in neural foramen Osseous Degenerative Disease o Intervertebral Disc Bulge • Generalized circumferential disc extension beyond vertebral ring apophyses o Facet Arthropathy, Cervical • Osteoarthritis of synovially lined apophyseal joints - facet overgrowth + joint space narrowing o Facet Arthropathy, Lumbar • Similar findings to cervical spine o Facet Joint Synovial Cyst • Extradural cystic mass communicating with facet joint + degenerative changes disc, facet joint • Lumbar (90%) > > cervical, thoracic Infection o Abscess, Epidural • Extradural spinal infection with abscess formation ± spondylodiscitis o Abscess, Paraspinal • Suppuration of paraspinal soft tissue from direct extension or hematogenous pathogen dissemination • Calcified psoas abscesses '* tuberculosis Trauma o Hematoma, Epidural-Subdural • Hypo-, iso-, or hyperintense depending on blood product age o Hematoma, Spontaneous Epidural • Accumulation of hemorrhage between dura & spine without significant trauma or iatrogenic procedure o Hematoma, Paraspinal • Frequently associated with vertebral body fracture • Signal intensity reflects blood product composition, age Neoplasm o Neuroblastic Tumor • Ganglioneuroma, ganglioneuroblastoma, and neuroblastoma • Intraspinal spread has important treatment and prognostic implications o

DIFFERENTIAL DIAGNOSIS

•

EXTRADURAL, NORMAL MARROW SIGNAL Lymphoma • Variable imaging manifestations are often nonspecific o SchwannOina • Schwann cell neoplasm of peripheral nervous system • Consider neurofibromatosis type 2 if many tumors identified o Neurofibroma • Nerve sheath tumor of spinal root, neural plexus, peripheral nerve, or end organs • Plexiform neurofibroma pathognomonic of NFl • Ligamentous Ossification o OPLL • Flowing multilevel ossification posterior to vertebral bodies • "Upside down T" or "bowtie" configuration on axial images o DISH • Bulky flowing anterior vertebral ossification • Thoracic> cervical, lumbar spine; R > > L (opposite aorta) o Ossification Ligamentum Flavum • Linear thickening and ossification of ligamentum flavum • Ligamentous Hypertrophy o Degenerative disc disease, redundancy and thickening of ligamentum flavum - spinal stenosis • Peridural Fibrosis o

Intervertebral

Disc Herniation,

Cervical

Sagiaal T2WI MR depicts a large rounded C5·6 disc extrusion (base of herniation is narrower than apex beyond the disc margin) effacing the thecal sac.

Enhancing scar formation within epidural space after lumbar surgery • Perineural Root Sleeve Cyst o Dilatation of arachnoid and dura of spinal posterior nerve root sheath o Most common in lower lumbar spine and sacrum (Tarlov cyst) o

Helpful Clues for Less Common Diagnoses • Epidural Lipomatosis o Excessive accumulation of intraspinal fat (~ 7 mm) compressing thecal sac - cord compression, neurologic deficits o Long-term exogenous steroid administration or excessive endogenous steroid production • Teratoma, Sacrococcygeal o Large heterogeneous sacral tumor ± calcification, cysts, hemorrhage o Rarely marrow invasion, even if adjacent soft tissue tumor or intraspinal spread through sacral hiatus Helpful Clues for Rare Diagnoses • Neurenteric Cyst o Intraspinal cyst lined by enteric mucosa (split notochord spectrum) o ± Vertebral abnormalities (persistent canal of Kovalevsky, segmentation and fusion anomalies)

Intervertebral

Disc Extrusion,

Foraminal

Axial T2WI MR demonstrates a large left L4-5 far lateral disc herniation BI extending into the left neural foramen

displacing

the exiling L4

nerve

root

II 5

lEI.

23

EXTRADURAL,

C1l

~ :J

NORMAL

MARROW

SIGNAL

-0 C1l

~ X

W

Ql

c: C-

oo

Facet Arthropalhy,

Cervical

Facet Arthropathy,

Lumbar

(Lefl) Axial bone CT

demonstrates severe osseous hypertrophy and facet degenerative changes that distort the articular joint surfaces. (RighI) Axial T2WI MR reveals severe bilateral facet degenerative changes, with enlargement of the facets and distortion of the articular surfaces, narrowing the lateral recesses. Ligamentous thickening also contributes to central canal stenosis.

Facet Joint Synovial Cyst

Abscess, Epidural

(Left) Axial T2WI MR shows a large left synovial cyst 1::1 associated with severe degenerative facet changes. Note significant compression of the thecal sac SI by cyst mass effect compounded by multifactorial spinal stenosis. (RighI) Sagittal T I C+ MR

demonstrates a long segment rim-enhancing

lumbar

epidural abscess without contributory discitis or marrow signal abnormality.

Abscess, Paraspinal (Lefl) Axial T I C+ FS MR shO\vs abnormal paraspinaf muscle enhancement with a {Deal abscess in a patient with septic facet joint infection. The vertebral body

=

and transverse process marrow

II 5 24

signal is normal.

(Righi) Sagittal T1 WI MR shows a typical appearance of a large subacute epidural hematoma demonstrating T 1 hyperintensity 1::1. This presentation was spontaneous and idiopathic; no underlying lesion was detected.

Hematoma,

Spontaneous

Epidural

EXTRADURAL,

Ossification

ligamentum

Flavum

NORMAL

MARROW

Peridural

SIGNAL

Fibrosis (Left) Axial T IWI MR demonstrates a small (Deus of asymptomatic ossification within the thoracic IigamenlUm flavum (Right) Axial TI C+ MR in a post-operative patient with pain shows diffuse enhancement of the right lateral epidural space and surrounding exiting foot secondary to peridural fibrosis. There is extensive enhancement of the disc curelte site

=.1.

=.

Perineural

Root Sleeve Cyst (Left) Axial TI C+ MR reveals an incidental, well-circumscribed, nonenhancing, inlraspinat CSF intensity root sleeve cyst at the L5 level. (Right) Sagittal T1WI MR shows marked epidural lipomatosis in a young cerebral palsy patient. Imaging was obtained after inability to place an epidural catheter. Note thick dorsal epidural fat proliferation that substantially narrows the central spinal canal and

=.1

compresses the thecal sac.

Teratoma,

Sacrococcygeal (Left) Sagittal T I WI MR reveals a heterogeneous sacral tumor that anteriorly displaces the reclUm and urinary bladder. Note absence of abnormal sacral marrow signal and lack

or

tumor extension into the spinal canal through the sacral hialUs. (Right) Sagittal TI WI MR shows a large ventral cystic mass in the spinal canal compressing the ventral spinal cord in contiguity with a second prevertebraf enteric cyst with similar signal characteristics.

=

a

II 5 25

EXTRADURAL, ABNORMAL MARROW SIGNAL

DIFFERENTIAL DIAGNOSIS Common • Vertebral Fracture with Epidural Hematoma • Osteomyelitis, Pyogenic • Metastases, Blastic Osseous • Metastases, Lytic Osseous • Osteomyelitis, Granulomatous • Multiple Myeloma • Plasmacytoma • Lymphoma • Hemangioma Less Common • Chondrosarcoma • Chordoma • Osteoblastoma • Aneurysmal Bone Cyst • Ewing Sarcoma Rare but Important • Extramedullary Hematopoiesis • Hemangiopericytoma • Osteosarcoma • Giant Cell Tumor • Echinococcus

ESSENTIAL INFORMATION

II 5 26

Helpful Clues for Common Diagnoses • Vertebral Fracture with Epidural Hematoma o May be seen following any cause of vertebral fracture (traumatic, compression, pathological) o Abnormal marrow signal reflects combination of edema, hemorrhage o Look for fracture line to confirm diagnosis • Osteomyelitis, Pyogenic o Bacterial suppurative infection of vertebrae, intervertebral disc o Ill-defined hypointense vertebral marrow (TIWI), destruction of vertebral endplate cortex on both sides of disc o Paraspinal ± epidural infiltrative soft tissue ± loculated fluid collection • Metastases, Blastic Osseous o Bone production> bone destruction o Lesion centered in posterior cortex initially ~ pedicle o Hematogenous dissemination (arterial or venous via Batson plexus) > perineural, lymphatic, CSF spread

• Metastases, Lytic Osseous o Bone destruction> bone production o Lesion centered in posterior cortex initially ~ pedicle o Usually enhances diffusely; may mask lesion if fat suppression not used • Osteomyelitis, Granulomatous o Granulomatous (tuberculosis, brucellosis, fungal) infection of spine + adjacent soft tissues • Tuberculosis: Gibbus vertebrae, relatively intact discs, large paraspinal abscesses • Brucellosis: Anterosu perior epi physitis with associated sacroiliitis • Multiple Myeloma o Multifocal malignant bone marrow proliferation of monoclonal plasma cells o Multifocal diffuse or heterogeneous Tl hypointensity, T2 hyperintensity, variable enhancement • Plasmacytoma o Solitary monoclonal plasma cell tumor of bone or soft tissue o Often lacks specific features to distinguish from solitary hematogenous metastasis • Lymphoma o Lymphoreticular neoplasms with wide variety of specific diseases, cellular differentiation o Protean imaging manifestations often nonspecific • Hemangioma o Typical "benign" (fatty stroma) hemangioma: Hyperintense on Tl WI and T2Wl MR + contrast enhancement o "Aggressive" hemangioma: Iso- to hypointense on Tl WI, hyperintense on T2WI + avid contrast enhancement • Lesion growth, bone destruction, vertebral collapse, absence of fat, active vascular component • May extend epidurally ~ cord compression Helpful Clues for Less Common Diagnoses • Chondrosarcoma o Primary or secondary (degeneration of osteochondroma or enchondroma) o Lytic mass ± chondroid matrix, cortical disruption, extension into soft tissues o Tumor cells produce chondroid matrix mineralization with "rings and arcs"

EXTRADURAL,

ABNORMAL

• Chordoma o Malignant tumor arising from notochord remnants o Sacrococcygeal> clivus> > vertebral body o Lesion center in posterior vertebral body, marked T2 hyperintensity help distinguish from hematogenous metastasis • Osteoblastoma o Benign, well-circumscribed, expansile lesion of neural arch with osteoid matrix o Peritumoral edema may obscure lesion, mimic malignancy or infection on MR • Aneurysmal Bone Cyst o Expansile neoplasm centered in neural arch containing thin-walled, blood-filled cavities o Fluid-fluid levels 2° hemorrhage, blood product sedimentation • Ewing Sarcoma o Usually seen in adolescents, younger adults o Permeative lytic lesion involves vertebral body, ribs before neural arch Helpful Clues for Rare Diagnoses

• Extramedullary Hematopoiesis o Epidural ± paravertebral proliferation of ectopic hematopoietic tissue in response to profound chronic anemia o Minimally enhancing isointense thoracic intra- or paraspinal masses + diffuse cellular marrow signal • Hemangiopericytoma

Vertebral

MARROW

SIGNAL

Hypervascular neoplasm arising from pericytes o Avidly enhancing lesion expanding/eroding spinal canal, with large soft tissue component • Osteosarcoma o Aggressive sarcoma containing matrix (immature, woven osteoid) produced directly by malignant cells o Wide zone of transition, permeative, cortical breakthrough, soft tissue mass o 80% have bone matrix visible on radiographs or CT • Giant Cell Tumor o Locally aggressive neoplasm composed of osteoclast-like giant cells o Lytic expansile lesion in vertebral body or sacrum with narrow zone of transition, non-sclerotic margin o Matrix absent; may have residual bone trabeculae • Echinococcus o Tapeworm infestation in endemic areas o Multiloculated, multiseptated T2 hyperintense mass with minimal enhancement o Liver, lung most common, bone involvement rare o

Fracture with Epidural Hematoma

Sagillal T1WI MR shows a C7 burst fracture =:I with canal compromise caused by bolh retropulsion of the fracture fragment and poslerior epidural hematoma 8l compressing the spinal cord.

Sagillal T1 C + M R reveals a large prevertebral rim-enhancing abscess extending from a C5-6 disc space infeclion E:I. There is a linear ventral epidural phlegmon that extends from C4 to C6 PJ:J.

=

II 5 27

EXTRADURAL,

ABNORMAL

MARROW

SIGNAL

Q)

c: a.

C/)

Osteomyelitis,

Granulomatous

(Left) sagiltal T1 C+ MR shows marrow enhancement and palhological thoracic vertebral fracture with relalive preservation of the intervertebral disc space. There is epidural extension with spinal cord compression in lhis case of lab-proven TB. (Right) sagiltal T1 C+ Fs MR depicts multiple enhancing vertebral metastases producing abnormal marrow enhancement in the cervical and thoracic spine. There is extensive epidural tumor extension at T5

=.

Plasmacytoma (Left) Axial T1 C+ Fs MR shows extensive rib & vertebral body tumor infiltration and marrow signal abnormality. The tumor produces a large enhancing epidural mass with secondary spinal cord compression. (Right) Axial T1 C+ Fs MR demonstrales extensive tumor infiltration of a lumbar vertebra extending into the right transverse process and paraspinal 50ft tissues. Characteristic appearance of the "curtain sign II confirms epidural extension.

=

Chondrosarcoma (Left) sagiltal T1 C+ MR reveals intense patchy enhancement of a destruclive vertebral mass (path-proven chondrosarcoma) with severe spinal cord compression secondary to dorsal epidural eXlension (RighI) Sagittal T7 C+ FS MR shows a destructive heterogeneously enhancing C3 vertebral tumor with large epidural mass producing spinal cord compression. T2WI MR (nOI shown) revealed diffuse T2 hyperintensity.

=.

II 5 28

Lymphoma

EXTRADURAL,

Osteoblastoma

ABNORMAL

MARROW

Aneurysmal

SIGNAL

Bone Cyst

rs

(Left) Axial T1 C+ MR demonstrates a heterogeneous mass EJ expanding the left pedicle with extensive enhancing reactive

perilumoral

edema

in the adjacent posterior elements, vertebral body, and 50ft tissues. (Right) Axial T1 C+ MR shows an expansile

mufti/oeulated

vertebral mass with multiple fluid-fluid levels. Note extensive

conical

destruction, severe canal stenosis, and enhancement of septae between dilated, blood-filled spaces.

Ewing Sarcoma (Left) Axial TI C+ MR demonstrates a large enhancing paravertebral mass that extends into the left epidural space through the ipsilateral neural foramen, displacing the spinal cord. (Rig"') Sagittal T1 C+ MR depicts a large, lobulated enhancing mass in dorsal 50ft tissues and dorsal spinal osseous elements. Note extension along dural margin,

compressing

the

thecal sac and displacing cauda

equina.

(Left) Sagittal T7 C+ MR shows L3 bone marrow

replacement by malignant tumor that permeates through the posterior cortex into the spinal canal and paraspinou5 50ft tissues. There is diffuse marrow

and

epidural enhancement associated with a pathologic fracture. (Right) Sagittal T1 C+ MR shows a large osseous expansile

mass

involving predominantly posterior

elements,

multiple fluid-fluid

the

with

levels and

diffuse mild enhancement.

II 5 29

EXTRADURAL

LESION,

DIFFERENTIAL DIAGNOSIS Common • Normal Epidural Fat • Epidural Lipomatosis • Hematoma, Epidural-Subdural Less Common • OPLL (with Fatty Marrow) • Extraosseous Hemangioma • Lipomyelomeningocele • Terminal Lipoma Rare but Important • Angiolipoma • Metastatic Melanoma

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Normal Epidural Fat o Usually most conspicuous dorsally in the thoracic region on midline sagittal slices o Key finding is lack of significant mass effect on the thecal sac • Epidural Lipomatosis o Overabundance of epidural fat, most commonly affecting thoracic and lumbar spine o Resulting compression of the thecal sac leads to a Y-shaped or trefoil cross section o May be associated with prolonged steroid administration or with hypercortisolism • Hematoma, Epidural-Subdural

II 5

Sagittal TI WI MR shows a typical case of epidural lipomatosis in a patient taking high dose corticosteroids.

11 HYPERINTENSE Actual signal characteristics depend on hematoma age; methemoglobin (subacute) hyperintense on Tl WI o Can be clearly differentiated from epidural fat with frequency-selective fat-suppressed sequence o

Helpful Clues for Less Common Diagnoses • OPLL (with Fatty Marrow) o Always ventral to thecal sac, mostly in cervical spine o OPLL will be most reliably defined on CT • LipomyeIomeningocele o Lumbosacral dysraphism • Everted elements of neural arch • Caudal fatty mass, contiguous with neural placode of a tethered, dysraphic cord; disjunction protrudes through the dysraphic defect • Skin-covered (closed spinal dysraphism) o Often discovered in infancy, but can be occult and come to attention during adolescence or adulthood • Terminal Lipoma o Lipoma of cord terminus or filum, often associated with tethered cord o Lipoma extends through caudal spondyloschisis, becomes confluent with subcutaneous fat o Not associated with myeloschisis: Represents disorder of regressive differentiation rather than of primary neurulation

Sagittal TI WI MR shows a case of subacute spontaneous epidural hematoma Compare with

=.

normal epidural fat dorsally I~~

30

EXTRADURAL

lESION,

11 HYPERINTENSE

OPLL (with Fatty Marrow) (Lell) Sagittal T1 WI MR shows a large local lumbar epidural hemorrhage, ellacing the thecal sac and

resulting in canal stenosis.

Hyperintense T1 signal is compatible with a subacute chronicity. (RighI) Sagittal T1WI MR shows compression of an atrophic

cord by an ossilied posterior longitudinal ligament with areas 01 latty marrow

=.

Extraosseous Hemangioma (Lell) Sagittal T1 WI MR shows atypical (lipid-poor) hemangioma 01 L5 with exlraosseous extension into the ventral epidural space

=. A second

lesion is

present at L 1 ~. (RighI) Sagittal T1 WI MR shows lumbosacral delect with tethered cord and caudal latty mass R>J in this inlant

=

with IipomyeJomeningoceJe.

Terminal

Lipoma (Lell) Sagittal T1WI MR shows a tethered cord terminating in a fatty mass. Overlying

neural arches are

intact. (RighI) Sagittal T I WI MR shows a large dorsal epidural T1 hyperintense mass

with heterogeneous

signal.

II 5 31

EXTRADURAL

ell L

::J

LESION, 11 HYPOINTENSE

""CJ

ell L

X

DIFFERENTIAL DIAGNOSIS

W Cl>

c:

·ii lJ)

Common • Disc Herniation • Osteophyte • Degenerated, Hypertrophic Ligamentum Flavum • Post-Operative Change, Normal o Epidural Gas o Metal Artifact o Peridural Fibrosis • Facet Joint Synovial Cyst • Epidural Fluid Collections o Pseudomeningocele o Hematoma (Acute) o Epidural Abscess • Epidural Metastatic Disease Less Common • Neurofibroma • Arachnoid Cyst • Ossification of the Posterior Longitudinal Ligament (OPLL) Rare but Important • Extramedullary Hematopoiesis • Extraosseous Component of a Hemangioma • Primary Bone Tumor o Plasmacytoma o Osteoblastoma o Aneurysmal Bone Cyst o Lymphoma/Leukemia o Giant Cell Tumor o Chordoma o Osteosarcoma o Chondrosarcoma o Ewing Sarcoma • Tumoral Calcinosis • Extradural Arteriovenous Fistula

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Vast majority of "extradural lesions" relate to degeneration of intervertebral disc and dorsal elements • Impact of epidural mass lesion on spinal cord and nerve roots is best evaluated with MR

II 5 32

• CT myelography alternative in patients who cannot undergo MR (e.g., pacemaker, spinal stimulator, etc.)

• Contrast-enhanced sequences recommended for evaluation of infection, tumor, and post-operative spine Helpful Clues for Common Diagnoses • Disc Herniation o Most common ventral epidural lesion at level of disc space o Extrusions extend away from disc space; sequestered fragments will be separated from disc level o "Vacuum disc phenomenon" (nitrogen gas) in disc herniation can manifest as epidural signal void • Peridural Fibrosis o Post-operative epidural scar/fibrosis in the surgical bed following discectomy, laminectomy o Peridural scar/fibrosis enhances, recurrent disc herniation won't enhance (distinction important as it influences decision to re-operate in cases of failed back surgery) • Facet Joint Synovial Cyst o Circumscribed cystic lesion contiguous with facet joint o Invariably associated with degenerative facet disease o If marked enhancement or severe T2 hyperintensity in adjacent marrow, consider infected facet joint • Pseudomeningocele o Epidural CSF collection at site of dural defect (post-surgical or post-traumatic) • Hematoma (Acute) o Lobulated collection, typically extending over multiple vertebral segments o Oxyhemoglobin and deoxyhemoglobin both isointense or hypointense on T1WI, becoming hyperintense in the subacute phase with the conversion to methemoglobin o No or relatively mild peripheral enhancement o May be spontaneous, due to coagulopathy, instrumentation, or trauma • Epidural Abscess o Lobulated collection, typically extending over 1-2 vertebral segments o Marked peripheral enhancement (abscess); epidural phlegmon may enhance more homogeneousl y

EXTRADURALLESION, T1 HYPOINTENSE

CJl

"'C

::::l

lD

Associated findings: Discitis/osteomyelitis, psoas abscess; patient typically has clinical signs of infection • Epidural Metastatic Disease o Epidural extension from bony vertebral metastasis (renal cell, lung, lymphoma) or transforaminal extension from paraspinal tumor (neuroblastoma) o

Helpful Clues for Less Common Diagnoses • Neurofibroma o Can be completely extradural, can also be intradural or transdural o Circumscribed margins, foraminal remodeling/ en largement a Rapid enlargement or pain: Consider malignant degeneration • Arachnoid Cyst a Typically dorsal to thecal sac, may extend laterally into neural foramina a Follows CSF on all pulse sequences a Chronic CSF pressure leads to remodeling and thinning of neural arch • Ossification of the Posterior Longitudinal Ligament (OPLL) a Longitudinal structure in ventral epidural space: When large, often develops central T1 hyperintensity (marrow space) a Cervical spine involvement more frequent than thoracic a Can cause significant canal compromise Helpful Clues for Rare Diagnoses • Extramedullary Hematopoiesis

Paravertebral and epidural lobulated masses; thoracic paraspinallocation most common o Associated with severe marrow hyperplasia due to chronic anemia • Extraosseous Component of a Hemangioma o Extraosseous extension of vertebral hemangioma, causing epidural soft tissue mass o Extraosseous component more frequently hypointense on Tl WI • Primary Bone Tumor o In general, MR superior in assessing epidural involvement, canal compromise, scope of marrow involvement, and extension into the paraspinal soft tissues o CT can be useful to assess matrix, zone of transition, etc. o

=-

Sagittal T1WI MR shows multiple disc herniations the largest herniation, at C3-4, associated with cord

compression.

n.

c

~ Ql

Alternative Differential Approaches • If lesion has very low or absent signal, shortens differential to o Metal artifact o Epidural gas (acute post-operative, traumatic) o Gas ("vacuum disc phenomenon") in a disc herniation o Ossified ligamentum flavum o OPLL o Tumoral calcinosis o Extradural arteriovenous fistula

Degenerated, Disc Herniation

m

~ ~ Ql

Hypertrophic Flavum

Ligamentum

Axial T1WI MR through L4-5 shows advanced degenerative facet arthropathy. Marked ligamentous hypertrophy is present ICB effacing the thecal sac posterolateralfy.

II 5 33

~

EXTRADURAL

LESION,

T1 HYPOINTENSE

::J

"0

~

X

w Q)

c: ~

(Left) Axial T1WI MR shows unifateral mild ossification in the ligamentum fJavum as well-defined low signal effacing the dorsal thecal sac 1:']. (Right) Axial T1WI MR shows epidural fibrosis extending from a laminotomy defect along the left of the thecal sac to the ventral epidural space. Homogeneous enhancement is typical.

Pseudomeningocele (Left) Axial T1WI MR shows a circumscribed extradural mass I:'] at the L4-5 level closely associated with the right facet joint. Cysts are better evaluated on T2 images or post-contrast. (Right) Axial T1 C+ MR shows a large CSF collection extending dorsally from a laminectomy defect I:'] into the subcutaneous tissues.

(Left) Sagittal Tl WI MR shows a large extradural collection dorsal to the thecal sac 1:']. Low Tl signal

was due to an acute chronicity and was expected

to become hyperintense as the collection aged. (Right) Sagittal Tl WI MR shows a ventral, epidural, mass-like process extending cephalad from the LJ-4 level 1:']. Key finding is that of extensive marrow changes ;n L3 and L4 vertebral bodies 81.

II 5 34

EXTRADURAL

Epidural Metastatic Disease

LESION,

11 HYPOINTENSE

Neurofibroma (Left) Axial Tl WI MR shows a chest wall mass !:1:l destroying the adjacent thoracic vertebra and extending into the epidural space EJI in this patient with non-small cell lung carcinoma. (Right) Axial TlWI MR shows a circumscribed soft tissue mass extending through a widened neural foramen to abut the thecal sac.

=

Ossification

of the Posterior longitudinal ligament (OPll)

Extramedullary Hematopoiesis (Left) Sagittal Tl WI MR

shows an extensive ossification of the posterior longitudinal ligament 1::1 resulting in canal stenosis

and cord compression. (Right) Axial TlWI MR shows an abnormally hypointense marrow signal and rounded hypointense 50ft tissue in the ventral epidural space o( the sacral canal in this patient with thalassemia.

=

Extraosseous Component Hemangioma

of a lymphoma/leukemia (Left) Sagittal Tl WI MR

shows a low signal mass involving the posterior thoracic body and dorsal elements, with an exlraosseous dorsal epidural 50ft

tissue mass

= resulting

in cord compression. (Right) Axial Tl WI MR shows an extensive abnormal marrow signal due to leukemia and a soft tissue mass in the epidural space of the sacral canal 1::1.

II 5 35

EXTRADURAL

lESION,

12 HYPERINTENSE,

Common • Intervertebral Disc Herniation • Synovial Cyst • Peridural Fibrosis • Epidural Fluid Collections o Abscess, Epidural o Hematoma, Epidural-Subdural • Epidural Metastatic Disease • Neurofibroma • Schwannoma Rare but Important • Primary Bone Tumor o Plasmacytoma o Lymphoma o Chordoma o Chondrosarcoma o Giant Cell Tumor o Ewing Sarcoma

• (Acute)

•

ESSENTIAL INFORMATION

II 5 36

Helpful Clues for Common Diagnoses • Intervertebral Disc Herniation o Most common epidural lesion in adult population o Intermediate-to-Iow T1 signal o Variable T2 signal, depending on disc hydration • Herniations of the protrusion and extrusion subtypes most frequently hypointense relative to normal disc • Sequestered disc fragments often of moderate-to-high T2 signal • Synovial Cyst o Circumscribed, fluid-filled structure o Variable iso- or hypointensity on T1 WI; centrally hyperintense on T2WI o Adjacent/contiguous with a facet joint o Cyst along ventral facet may impinge on thecal sac or nerve root o Seen with degenerative facet changes • Peridural Fibrosis o Epidural scar formation following spinal surgery o Normal post-operative finding o Infiltrative morphology, rarely mass-like o Isointense T1; variable T2 signal, usually hyperintense relative to disc material o May surround nerve root

Can only be differentiated from recurrent disc herniation on post-contrast imaging • Peridural fibrosis will homogeneously enhance, blending into extradural fat on non-FS TlWI Abscess, Epidural o May be associated with disc space infection or instrumentation/direct inoculation o Contents typically approximate fluid signal on Tl/T2WI • Increased T1 signal (isointense) may occur secondary to increased protein content o Marked peripheral enhancement typical on post-contrast imaging Hematoma, Epidural-Subdural (Acute) o May be spontaneous or associated with trauma or instrumentation o Signal varies with the age of the hemorrhage • Acute hemorrhage (oxyhemoglobin) isoor mildly hypointense on Tl WI, hyperintense on T2WI o Minimal or no enhancement on post-contrast imaging Epidural Metastatic Disease o Enhancing soft tissue mass, may be multiple o Most often associated with epidural extension from a vertebral metastasis o May also occur with transforaminal spread from a paraspinal or posterior mediastinal tumor Neurofibroma o Enhancing nodular, fusiform, or dumbbell mass associated with a nerve root o Epidural neurofibroma typically intraforaminal or transforaminal o May be associated with vertebral scalloping, thinning/remodeling of pedicles o Most (90%) solitary, nonsyndromic o May be multiple, extensive; associated with plexiform neurofibromas (neurofibromatosis type 1) Schwannoma o Enhancing nodular, fusiform, or dumbbell mass associated with a nerve root o

DIFFERENTIAL DIAGNOSIS

•

•

•

11 ISOINTENSE

EXTRADURAL

lESION,

12 HYPERINTENSE,

Most schwannoma intradural; epidural schwannoma typically intraforaminal or transforaminal o Not reliably distinguished from solitary neurofibroma

o

Helpful Clues for Rare Diagnoses • Plasmacytoma o Solitary plasma cell tumor, osteolytic tumor, ± compression fracture, ± extraosseous extension o Often indistinguishable from lytic metastases • Lymphoma o Enhancing epidural mass or epidural extension from a vertebral lesion o Often indistinguishable from metastases o Spinal lymphoma may also manifest with leptomeningeal or intramedullary lesions • Chordoma o Arises from notochord remnants: Midline, osteolytic tumor o Sacrococcygeal location most common, followed by clivus; vertebral lesion rather uncommon o May extend into epidural/paraspinal spaces o Heterogeneous iso- or hypointense on T1WI; marked hyperintensity on T2WI o Variable enhancement • Chondrosarcoma o Destructive tumor, chondroid matrix o Iso- or hypointense on Tl WI; marked hyperintensity on T2WI

Intervertebral

Disc Herniation

11 ISOINTENSE

Heterogeneous enhancement • Giant Cell Tumor o Lytic, expansile vertebral body lesion; narrow zone of transition o May extend into epidural/paraspinal spaces o Heterogeneous iso- or hypointense on Tl WI; heterogeneous hyperintensity on T2WI • Areas of low-to-intermediate T2 signal may reflect areas of high collagen content and hemosiderin deposition o Propensity to extend across sacroiliac joint & disc space is unusual for other lesions and may simulate infection • Ewing Sarcoma o Destructive tumor o Iso- or hypointense on Tl WI; moderate to hyperintense signal on T2WI o Paraspinal soft tissue mass often a feature of spinal Ewing sarcoma o

Intervertebral

Disc Herniation

II Axial T7WI MR shows sequestered disc fragment in the left anterolateral spinal canal The fragment is similar in signal to skeletal muscle on T7WI.

=.

Axial T2WI MR shows the same disc sequestration on T2WI =1 in which it is hyperintense to both skeletal

5

muscle and to normal disc material.

37

~

EXTRADURAL

lESION,

T2 HYPERINTENSE,

T1 ISOINTENSE

:J

"0

ro ~ X

W

Gl

c: ~

(Left) Axial T1WI MR shows

an abnormal rounded mass in Ihe righllateral canal

=

spinal

that is in continuity

wilh a degeneraled facel join/. The mass has intermediale signal on T I WI. (Right) Axial T2WI MR

=-

shows the same mass on T2WI in which Ihere is a sharply circumscribed margin, Ihin wall, and hyperintense signal centrally. Nole Ihe increased fluid within both facel joints and a sublfe protrusion of Ihe lefl facet's synovial capsule

Peridural Fibrosis

Peridural Fibrosis

Abscess, Epidural

Abscess, Epidural

(Left) Axial T1 WI MR shows post-operative peridural fibrosis as abnormal soft tissue Ihat replaces the normal (brighO epidural fal between the anterolateral margin of the thecal sac and the left S 7 nerve root sleeve~. (Right) Axial T2WI MR in Ihe same patient shows epidural fibrosis to be heterogeneously hyperintense on FSE T2WI, approaching Ihe intensily of epidural fa/.

=

=

(Left) Sagillal T1 WI MR shows a L]-4 disc space infection with replaced marrow signal in adjacent vertebra and a ventral epidural abscess hypoinlense on T1 WI. A second dorsal epidural collection is a/so present. (Right) Sagillal T2WI MR in the same patient shows the ventral phlegmon as moderalely hyperinlense on T2WI The full exlent of the dorsal collection is more apparenl ~ and approaches CSF in hyperintensily.

=

=

=.

II 5 38

EXTRADURAL

lESION,

12 HYPERINTENSE,

11 ISOINTENSE

CIl

~. ::l CD

m ~ ~ OJ Hematoma,

Epidural-Subdural

(Acute)

Hematoma,

Epidural-Subdural

0-

(Acute)

C

~

(Left) Sagittal T1WI MR shows an acute epidural

hematoma

=- isoin£ense

OJ to

lhe cord on T1WI, associaled wilh bursl fracture of C7 81. (Right) Sagittal STIR MR in the same patient shows a T2 hyperintense dorsal epidural

hematoma

= associated

wilh C7 burst fracture 81.

Epidural Metastatic

Disease

Epidural Metastatic

Disease (Left) Axial T1 WI MR in lhis patient with metastatic lung

carcinoma shows a large metastatic lesion to C2 with preverlebral PJ:J:l and epidural lID extension, isoinlense to cord and skelelal muscle on T IWI, effacing lhe lhecal sac

and compressing the cervical cord 81. (Right) Axial T2' eRE MR in the same palienl shows lhe epidural sofllissue =:I 10 be moderately hyperintense on T2 weighted imaging

Neurofibroma

Neurofibroma (Left) Axial T1 WI MR shows a large lransforaminal mass, hypointense on T I WI, enlarging lhe lefl Lt-2 neural foramen.

The intraspinal

componenl =:I mildly effaces lhe thecal sac. (Right) Axial T2WI MR in lhe same palient shows more clearly lhe foraminal widening and lhecal sac effacement by lhe intraspinal

component

1tJ.

Note the central hypointensity with surrounding T2 hyperintensity, demonstrating the "target sign" of a neurofibroma.

II 5 39

EXTRADURAL

LESION, 12 HYPOINTENSE,

DIFFERENTIAL DIAGNOSIS Common • Intervertebral Disc Herniation • Endplate Osteophyte • Facet Osteophyte • Ossification Ligamentum Flavum • OPLL • Epidural Gas • Metal Artifact Rare but Important • Epidural AVF

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Intervertebral Disc Herniation o Most common epidural lesion in adult population o Intermediate-to-Iow Tl signal o Variable T2 signal, hyperintense signal can be seen with annular fissures and sequestrations • Endplate Osteophyte o Endplate osteophyte formation commonly accompanies degenerative disc disease o May be difficult to distinguish osteophyte from a disc herniation on MR; NECT can supplement evaluation • Ossification Ligamentum Flavum o Enlargement of ligamentum flavum causing variable posterolateral encroachment on the thecal sac o Best conspicuity of calcifications on NECT

T1 HYPOINTENSE

If sufficiently ossified, may produce marrow space with hyperintensity on TlWI o Idiopathic, probably related to hydroxyapatite or calcium pyrophosphate deposition o May observe changes of DISH or OPLL elsewhere in spine • OPLL o Idiopathic condition, resulting in calcification and thickening of the posterior longitudinal ligament o Most common in the cervical spine, can involve upper thoracic o Variable encroachment on the ventral spinal canal o If sufficiently ossified, may produce a marrow space with hyperintensity on TlWI • Epidural Gas o Routinely seen in the acute post-operative period o Can occur from • "Vacuum" disc phenomenon extending into disc herniation • "Vacuum" joint phenomenon extending into facet synovial cyst • Metal Artifact o Epidural catheters o Spinal cord stimulators o Spinal fusion hardware o Displaced intervertebral devices o

Intervertebral

Disc Herniation

II 5

Sagittal T1WI MR shows a large disc extrusion at L4-5.

Extruded disc material is similar in signal to the remainder of the intervertebral disc on T I WI.

40

Sagittal T2WI MR again shows large disc exlfusion that is hypointense on T2WI.

EXTRADURAL

LESION, 12 HYPOINTENSE,

11 HYPOINTENSE

(Left) SagiLlal T IWI MR

shows severe disc space narrowing at LS-SI with small endplate osteophytes Small disc extrusion is present at L4-S~. (Right) SagiLlal T2WI MR also shows endplate osteophytes at LS-SI =.2 and the small disc extrusion at L4-S~.

=.

Ossification

Ligamentum

Flavum

Ossification

Ligamentum

Flavum (Left) Axial T1 WI MR shows hypointense signal within a thickened thoracic ligamentum f1avum with mild posterolateral effacement of the thecal sac. (Right) Axial T2WI MR also shows hypoinlense signal associated with the thickened, ossified ligamentum f1avum

=

=

Metal Artifact (Left) SagiLlal T1WI MR shows two level fusion from

C3 to C5 with metal artifact from screws Screw artifact at C5 level extends to the ventral epidural space adjacent to the cord S.

=.

Note the congenital

fusion at

C6-7. (Right) SagiLlal T2WI MR again shows metallic artifact in epidural space at C5S due to malpositioned screw from anterior

cervical

fusion.

II 5 41

~ OJ

:J

LUMBAR SOFT TISSUE MASS, PEDIATRIC

"0

~ OJ

X w Q)

c: C-

oo

DIFFERENTIAL DIAGNOSIS Common • Lipomyelomeningocele • Myelomeningocele • Lipoma, Spinal • Spinal Muscle Injury, Traumatic • Scoliosis Less Common • Plexiform Neurofibroma • Ewing Sarcoma • Lymphoma • Venous Vascular Malformation • Lymphatic Malformation • Abscess, Paraspinal Rare but Important • Metastases, Lytic Osseous • Hemangiopericytoma • Meningocele, Dorsal Spinal • Pseudomeningocele

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Appearance of overlying skin, pertinent clinical information helps limit differential list

II 5 42

Helpful Clues for Common Diagnoses • Lipomyelomeningocele a Lipomyelocele = neural placode-lipoma complex contiguous with subcutaneous fat through dysraphic defect, attaching to and tethering spinal cord a Lipomyelomeningocele = lipomyelocele + meningocele, enlargement of subarachnoid space, displacement of neural placode outside of spinal canal • Myelomeningocele a Posterior spinal defect lacking skin covering => neural tissue, CSF, and meninges exposed to air a Lumbosacral (44%) > thoracolumbar (32%) > lumbar (22%) > thoracic (2%) a Low-lying cord on post-operative MR imaging does not always = clinical tethering • Lipoma, Spinal a Arise from premature separation (dysjunction) of cutaneous ectoderm from neuroectoderm during neurulation

Profound hypodensity on CT and Tl WI hyperintensity characteristic of fat a Use chemical fat saturation or inversion recovery MR techniques to confirm fat content • Spinal Muscle Injury, Traumatic a Paraspinal muscle fiber disruption from indirect forces => abnormal muscle T2 hyperintensity and swelling a Most commonly from MVA; also athletic injuries, blow from falling objects, direct injury • Scoliosis a General term for any lateral curvature of spine • Dextroscoliosis: Curve convex to right • Levoscoliosis: Curve convex to left • Kyphoscoliosis: Scoliosis with component of kyphosis • Rotoscoliosis: Scoliosis which includes rotation of vertebrae a Short-curve scoliosis usually has underlying abnormalities; consider congenital, neoplasm, or inflammation a

Helpful Clues for Less Common Diagnoses • Plexiform Neurofibroma a Long, bulky, multinodular nerve enlargement is pathognomonic for NFl a Often affects sacral or brachial plexi • Ewing Sarcoma a S% of all Ewing tumors in spine (sacrum> rest of spine) a Usually in adolescents or younger adults a Permeative lytic lesion of vertebral body or sacrum involving vertebral body before neural arch • Contiguous spread along peripheral nerves from spine or sacral primary, but may originate in soft tissues • Lymphoma a Lymphoreticular neoplasms with wide variety of specific diseases & cellular differentiation a Multiple types demonstrate variable imaging manifestations • Venous Vascular Malformation a Congenital trans-spatial vascular malformation of venous channels present from birth

LUMBAR SOFT TISSUE MASS, PEDIATRIC May be mass-like, frequently enhances moderately (less than soft tissue hemangioma) a No arterial vessels within lesion, venous channels may be large a Look for phleboliths to make specific diagnosis • Lymphatic Malformation a Congenital trans-spatial vascular malformation of lymphatic channels present from birth a Typically minimal to no enhancement, although septations may enhance, especially if previously inflamed a Fluid-fluid levels strongly suggest diagnosis a May grow rapidly if hemorrhage or concurrent viral infection • Abscess, Paras pinal a Suppuration of paraspinal soft tissue from direct extension or hematogenous dissemination of pathogens a Identification of calcified psoas abscesses suggests tuberculous paraspinal abscess a

Helpful Clues for Rare Diagnoses • Metastases, Lytic Osseous a Osteolytic metastases of primary tumor to spine; bone destruction exceeds bone production ~ lytic rather than blastic a Lesion usually destroys posterior cortex, pedicle first • Hemangiopericytoma

Vividly enhancing hypervascular neoplasm arising from pericytes expanding/eroding spinal canal with large soft tissue component a Dural-based if primary, epicenter in bone if metastatic a Previously called angioblastic meningioma, but probably different tumors • Meningocele, Dorsal Spinal a Skin-covered dorsal dural sac containing arachnoid, CSF protruding thorough posterior osseous defect into subcutaneous tissues • Always skin-covered; skin may be dysplastic or ulcerated a Lumbosacral junction, sacrum> > cervical, thoracic • Mild cases may show only absent spinous process or localized spina bifida • More severe cases show multisegmental spina bifida, spinal canal enlargement • Pseudomeningocele a CSF-filled spinal axis cyst with supportive post-operative or post-traumatic ancillary findings a Cyst contiguous with thecal sac, not lined by meninges a Fat-saturated T2WI best sequence to demonstrate pseudomeningocele and localize dural communication a

lipomyelomeningocele

Sagillal T7WI MR demonsl,ales a low-lying spinal cord inserting into a large lipomatous malformation that is contiguous with subcutaneous fat extending through a poslerior dysraphic defect

Sagillal T7WI MR shows a large unrepaired myelomeningocele sac 1m. Neural elements are seen protruding into the sac which was not skin covered, confirming diagnosis of myelomeningocele.

II 5

a

43

LUMBAR SOFT TISSUE MASS, PEDIATRIC

<1l

~ :::J

"0 <1l

~ X

ill Q)

c:

enC-

Spinal Muscle Injury, Traumatic (Left) Sagittal T1 WI MR demonSlrates a large terminal lipoma adherent to the distal spinal cord contiguous with subcutaneous fat in a patient clinically presen!ing with a palpable lumbar mass. (RigM) Axial T2WI MR in a trauma patient with back pain and swelling reveals characteristic diffuse soft tissue edema in the right paraspinal muscles and subcutaneous tissues.

rs

Scoliosis

Plexiform

Neurofibroma

(Left) Axial T2WI FS MR in a patien! with VACTERL demonstrates prolrusion of the left paraspinal soft tissues due 10 congenital scoliosis, explaining palpable area of clinical concern. Note also dysplastic right kidney~. (RighI) Axial STIR MR in this patient with neurofibromalOsis type 1 reveals two palpable T2 hyperintense soft tissue plexiform neurofibromas

=

=.

Ewing Sarcoma (Left) Axial T2WI FS MR depicts a large pelvic [wing sarcoma with fUmor extension

into the

lumbosacral soft tissues, producing pain and a clinically palpable mass. (Right) Axial T 1 C+ MR demonstrates a large enhancing thoracolumbar epidural mass at the site of palpable concern, extending into the paraspinal muscles and epidural space.

II 5 44

lymphoma

lUMBAR

Venous Vascular Malformation

SOFT TISSUE MASS, PEDIATRIC

lymphatic

Malformation (Left) Axial TI C+ FS MR

shows homogeneous enhancement

within a

subcutaneous

dorsal soft

tissue mass. The size of this clinically palpable mass changed with position and onset of crying. (Right) Axial f2WI FS MR reveals a large abdominal 81 lymphatic malformation

with

trans-spatial extension into the right lumbar flank soft

=

lissues of this palient with Proteus syndrome. Note characterislic fluid-fluid level

PJ:2l.

(Left) Axial TI C+ MR following posterior spinal fusion reveals a large rim-enhancing fluid collection that surrounds the hardware with marginal inflammation in the dorsal

=

paraspinal

soft tissues.

(Right) Axial TI C+ MR shows a large, lobulated, paravertebral enhancing mass that involves the left dorsal elements 81. Note extension along dural margin into left neural foramen

1m.

Pseudomeningocele (Left) Sagillal TI WI MR shows mildly low-lying conus at L2 and large skin-covered dorsal CSF signal mass communicating with the thecal sac via a very thin, fluid signal pedicle traversing the posterior elements Ii8 (Right) Axial aWl MR shows a large CSF signal fluid collection in the dorsal lumbar soft tissues, extending From the right

=

hemilaminectomy

site into

subcutaneous tissues. There is no displacement or mass eFFectupon the thecal sac.

II 5 45

SECTION 6 Intrad u ral- Extramed ullary Anatomically Based Differentials Cauda Equina Enhancement, Diffuse Subarachnoid Space Narrowing Intradural/Extramedullary, Leptomeningeal

Enhancement

11-6-2 11-6-6 11-6-8

Generic Imaging Patterns Intradural/Extramedullary Lesion, No Enhancement Intradural/Extramedullary Lesion, Solid Enhancement Intradural Lesion, Serpentine Intradural/Extramedullary Lesion, Multiple

Modality-Specific Intradural/Extramedullary Intradural/Extramedullary Intradural/Extramedullary Intradural/Extramedullary Intradural/Extramedullary

11-6-12 11-6-14 11-6-18 11-6-20

Imaging Findings

Lesion,Ring/Peripheral Enhancement Lesion, T1 Hyperintense Lesion, T1 Hypointense Lesion, T1 Hypo, T2 Hypo Lesion, T2 Hyper, T1 Iso

11-6-22 11-6-26 11-6-28 11-6-32 11-6-34

Clinically Based Differentials Cauda Equina Syndrome

11-6-36

CAUDA

EQUINA

ENHANCEMENT,

DIFFERENTIAL DIAGNOSIS Common • Spinal Meningitis • CSF Disseminated Metastases • Guillain-Barre Syndrome • CMV Polyradiculopathy Q)

c: c.

en

less Common • Sarcoidosis • Arachnoiditis • Lymphoma • Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) • Spinal Stenosis Compression • Disc Herniation Compression • Hereditary Motor & Sensory Neuropathies Rare but Important • Viral Radiculomyelitis • Rabies • Tick-Borne Encephalitis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Limited imaging differential considerations include single vs. multiple root involvement, smooth vs. nodular enhancement a Multiple root involvement most common and least specific for a single diagnosis a Single root involvement over long segment favors radiculitis secondary to disc herniation or stenosis a Smooth enhancement most common and least specific a Nodular enhancement much more likely with tumor or sarcoidosis

II 6 2

Helpful Clues for Common Diagnoses • Spinal Meningitis a Shows diffuse, smooth enhancement of multiple roots and distal pial surface of cord a Look for additional lesions such as subdural spinal empyema, epidural abscess or phlegmon a Nonspecific appearance for etiology, whether pyogenic, granulomatous, fungal a Clinical history critical => LP mandatory • CSF Disseminated Metastases

DIFFUSE

Metastatic disease may show either diffuse smooth enhancement or more nodular form a Lung, breast carcinoma most common for systemic primaries a PNET, GBM most common for CNS primaries a Look for bony metastases, retroperitoneal lymphadenopathy • Guillain-Barre Syndrome a Acute inflammatory demyelinating polyradiculopathy (AIDP) a 1-2 cases/IOO,OOO per year a Monophasic demyelinating polyneuropathy related to prior infection, esp. Campylobacter jejuni enteritis • GB characterized by ascending limb weakness and areflexia • Cranial nerve involvement in 50% • Back pain 30-50% • Respiratory failure • Autonomic instability with labile BP, cardiac arrhythmias • Progression to plateau in 2 weeks a Number of variants described • Miller Fisher syndrome (MF) => ophthalmoplegia, ataxia, areflexia • => Bickerstaff encephalitis appears closely related to MF with addition of alteration of consciousness or long tract signs • Acute post-infectious axonal polyradiculoneuropathy (AMSAN) • Acute motor axonal neuropathy (AMAN) • Acute sensory ataxic neuropathy (ASAN) • Relapsing variants a Treat with plasma exchange and IVlg a 10% have permanent disability • Poor prognosis can be predicted based on age, preceding diarrhea, and disability score 2 weeks from presentation a Molecular mimicry => infectious agent sharing epitopic determinants with nerve tissue incites immune response leading to nerve inflammation a GB & variants represent autoimmune disease to glycolipid structures • Campylobacter jejuni => GM1, GMlb, GDla, GalNac-GDla, GQlb • Haemophilus influenza => GM1, GTla • Mycoplasma pneumoniae => a

Galacterocerebroside

CAUDA EQUINA

ENHANCEMENT,

• Cytomegalovirus => GM2 Microbial genetic polymorphism can determine clinical presentation of human autoimmune disease • C. jejuni strain with gene cst-ll(ThrSl) has GMI or GDla epitope => Guillain-Barre • C. jejuni strain with gene cst-ll(AsnSl) has GQlb epitope => Miller Fisher syndrome • CMV Polyradiculopathy o Infection in AIDS, impaired cell mediated immunity o Assess for other infectious lesions => Toxo, crypto, TB, PML o May progress rapidly with anesthesia and weakness, variable amount of pain o Estimated 10% of AIDS patients have clinical deterioration related to CMV o CMV radiculitis in 3% of autopsies of AIDS patients o

Helpful Clues for less Common Diagnoses • Chronic Inflammatory Demyelinating Polyneuropathy (Cmp) o Group of disorders of peripheral nerves with similar clinical features o Must be distinguished from hereditary, metabolic, and diabetic neuropathies o Aberrant cellular and humoral immune response to peripheral nerve antigens o Unlike GB, CIDP is rarely preceded by infection & involved antigens are unknown

DIFFUSE

CIl '0 ::::J CD

Treatment with corticosteroids, plasma exchange, IVIg o Nerve hypertrophy of multiple roots in symmetrical fashion o May mimic appearance of multiple schwannomas or neurofibromas with NF2 or Nfl, respectively • Spinal Stenosis Compression o Typically focal, mild enhancement of cauda equina at single level of severe central canal stenosis o Multiple levels suggests other etiology than stenosis • Disc Herniation Compression o Single lumbar root enhancing over long s~gment related to compression by caudal disc herniation o Enhancement may reflect intrinsic neural abnormality or distended radicular vein o 0 clear relationship to symptoms or outcome o

SELECTED REFERENCES I.

Koga M et al: Campylobacter jejuni cst-II polymorph isms and association with development of Guillain-Barre syndrome. Neurology. 69(17):1727-8; author reply 1728, 2007

2.

Steininger : Clinical relevance of cytomegalovirus infection in patients with disorders of the immune system.

3.

4.

Clin Microbiollnfec!. 13(10):953-63,2007 Willison HJ: Gangliosides as targets for autoimmune injury to the nervous system. J Neurochem. 103 Suppl 1: 143-9, 2007 Yuki N et al: Axonal Guillain-Barre syndrome: carbohydrate mimicry and pathophysiology. J Peripher Nerv Sys!. 12(4):238-49,2007

CSF Disseminated Metastases

rs

Sagiltal T7WI MR shows poslerior epidural abscess wilh cauda cquina compression, L3-4 disc space infectjon EI with body enhancement, and meningitis with dislal diffuse nerve rool enhancement

&'

=

Sagillal TI WI FSMR shows multiple enhancing nodules in distal cauda equina EJ from lung carcinoma metastases. Marrow signal is normal. Nodular foci

indicate tumor or granulomatous disease.

II 6 3

CAUDA

EQUINA

CSF Disseminated (Left) SagiHal T1 C+ MR shows glioblastoma drop metastases as multiple globular irregular areas of enhancement along the clumped cauda equina and distal cord 81. (RighI) Sagittal T1 C + M R shows multiple enhancing cervical rootlets in this patient with Cuiflain-Barre and

=

respiratory

failure.

(Left) Axial T1 C+ MR shows

extensively enhancing

=

ventral and dorsal nerve roots which spare the distal cord. Ventral enhancement predominating for motor variant of Guillain-Sarre. (Right) Axial T1 C+ fS MR shows diffuse cauda equina enhancement of multiple roots due to AIDS polyradiculopathy (CMV) No focal masses are present History is critical is typical

=.

since appearance

is

nonspecific.

(Left) Sagittal T1 C+ MR shows a variant case of spinal sarcoidosis, revealing multiple subarachnoid nodules interspersed

=

among the cauda equina. (Right) Sagittal T1 C+ MR shows leptomeningeal root enhancement

from

disseminated intrathecal leukemic metastasis encircling the distal spinal cord and infiltrating the cauda equina.

=..

II 6 4

ENHANCEMENT,

Metastases

DIFFUSE

Guillain-Barre Syndrome

CAUDA EQUINA

Chronic Inflammatory Polyneuropathy

Demyelinating (ClOP)

ENHANCEMENT,

DIFFUSE

Spinal Stenosis Compression (Left) Axial T1 C+ MR shows a typical case of spinal chronic

inflammatory

demyelinating polyneuropathy (ClOP), with enlargement and abnormal

=

nerve enhancement

of both

intradural and extradural !::l components. (Right) Axial T1 C+ MR shows focal root enhancement

at site of

severe central stenosis

Disc Herniation

Compression

e.

Hereditary Motor & Sensory Neuropathies (Left) Axial T I C+ MR shows single rool enhancement [;>l due to disc herniation at L4-5 level (not shown), reflectmg radiculitis. Engorged radicular vein may show similar finding. (Right) Sagillal T1 C+ MR shows diffusely thickening and mildly enhancing nerves of the cauda equina in this patient with Charcot-Marie-Tooth.

Viral Radiculomyelitis

Tick-Borne

Encephalitis (Left) Axial T1 C+ MR shows

enhancement of the cord and cauda equina Nile virus is an arthropod-borne

=. West

flavivirus

that can cause meningitis, encephalitis, acute flaccid paralysis, or poliomyelitis-like syndrome. (Right) Sagittal T1 C+ MR shows rickellsial infection (Rocky Mountain spotted fever) with diffuse cauda equina enhancement

=.

II 6 5

SUBARACHNOID SPACE NARROWING

Ql

c: Co

en

Common • Stenosis, Acquired Spinal • Stenosis, Congenital Spinal • Extra-axial Mass o Hematoma, Epidural-Subdural o Abscess, Epidural o Meningioma o Metastasis, Epidural o OPLL • Enlarged Cord o Demyelinating Disease • Multiple Sclerosis, Spinal Cord (Acute) • ADEM, Spinal Cord • Acute Transverse Myelitis, Idiopathic • Neuromyelitis Optica o Syringomyelia o Ependymoma, Cellular, Spinal Cord o Astrocytoma, Spinal Cord o Metastases, Spinal Cord o Radiation Myelopathy Less Common • Arachnoiditis, Lumbar

•

•

•

•

•

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Stenosis, Acquired Spinal o Multifactorial process involving disc herniation and degenerative hypertrophy of the posterior elements • Stenosis, Congenital Spinal

Stenosis, Acquired

II 6 6

Developmentally narrow canal; short, thick pedicles o Frequency: Lumbar> cervical> thoracic Hematoma, Epidural-Subdural o May be spontaneous or associated with trauma or instrumentation o Signal varies with the age of the hemorrhage o Mild or no enhancement Abscess, Epidural o May be associated with disc space infection or instrumentation/inoculation o Marked peripheral enhancement typical Meningioma o Dural-based, circumscribed, enhancing mass Multiple Sclerosis, Spinal Cord (Acute) o Cord expansion uncommon, indicates an acute lesion; resolves in 6-8 weeks o Hyperintense on T2WI, variable enhancement o Image brain to check for supratentorial lesion(s) Ependymoma, Cellular, Spinal Cord o Circumscribed, enhancing intramedullary mass o Necrosis and hemorrhage possible Astrocytoma, Spinal Cord o Fusiform enlargement, infiltrative margins; no or variable enhancement o Imaging cannot reliably differentiate from ependymoma o Appearance can be simulated by acute MS, ADEM, neuromyelitis optica, myelitis o

DIFFERENTIAL DIAGNOSIS

•

Spinal

Axial CECT (CT myelogram) shows almost complele 1055of the CSF spaces wilhin the thecal sac due 10 protruding disc, facet arlhropathy and ligamenlous hypertrophy ~.

=-

Sagiltal T2WI MR shows a congenilally small cervical canal, with virtually complete 1055of the CSF spaces surrounding the cord althe CJ-C5 levels.

SUBARACHNOID

Hematoma,

Epidural-Subdural

SPACE NARROWING

Abscess, Epidural (Left) Axial T2WI MR shows

a ventral, lentiform epidural hemorrhage compressing the thecal sac and dorsally displacing the fibers of the cauda equina. (Right) Sagillal T2WI MR shows a large ventral epidural collection =:lI extending from C2 into the upper thoracic spine, effacing the CSF space of the cervical canal and

compressing the cervical cord. Note myelopathic signal changes d>:.

Metastasis,

Epidural (Left) Sagillal n C+ MR shows circumferential enhancing epidural soft ti.<sue=:lIthat effaces the CSF spaces of the

mid-thoracic spine and causes cord compression in this patient with lymphoma. Note prevertebral soft tissue S> as well. (Right) Sagittal T2WI MR shows thickened, ossified posterior longitudinal ligament =:lI effacing the thecal sac and focally compressing the cervical cordE!lll.

Neuromyelitis

Optica

Astrocytoma,

Spinal Cord (Left) Sagillal T2WI MR shows effacement of the extramedullary CSF spaces by a long segment of fusiform cervical cord enlargement. Cord

enlargement is accompanied by diffuse T2 hyperinlensity. (Right) Sagillal T2WI MR shows loss of subarachnoid spaces due to a large

heterogeneous mass enlarging the cervical cord and the associated syrinx 1tJ.

II 6 7

INTRADURAl/EXTRAMEDULLARY,

~ ro :::J

"0 Q)

E ro ~

;(

w,

ro ~ :::J "0 ro ~

C Q)

c: Co

C/)

DIFFERENTIAL DIAGNOSIS Common • Guillain-Barre Syndrome • Metastases, CSF Disseminated • Meningitis, Spinal • Ependymoma, Myxopapillary, • Neurofibromatosis Type I o Neurofibroma

Spinal Cord

Less Common • Neurofibromatosis Type 2 o Schwannoma • Lymphoma • Leukemia • Chemical Meningitis Rare but Important • Sarcoidosis • Arachnoiditis, Lumbar • Hypertrophic Neuropathy • Anterior Radiculopathy Syndrome • ClOP

• Malignant

Peripheral Nerve Sheath Tumors

ESSENTIAL INFORMATION

II 6 8

LEPTOMENINGEAL

ENHANCEMENT

Infection of spinal cord leptomeninges and subarachnoid space o Smooth or irregular diffuse extensive meningeal enhancement or diffuse cerebral spinal fluid (CSF) enhancement • Ependymoma, Myxopapillary, Spinal Cord o Slow-growing glioma arising from ependymal cells of filum terminale o Enhancing cauda equina mass ± hemorrhage occurring nearly exclusively in conus, filum terminale, cauda equina • Neurofibromatosis Type 1 o Neurofibroma • Localized (90%), diffuse, or plexiform (pathognomonic for NFl) neoplasms of nerve sheath origin • Intradural/extramedullary common, may extend outside neural foramen in dumbbell shape • Cervical> thoracic, lumbar o

Helpful Clues for Less Common Diagnoses • Neurofibromatosis Type 2 o Schwannoma • Peripheral nervous system nerve sheath neoplasm • Multiple in NF2; identification of other classic lesions (vestibulocochlear or trigeminal schwannomas) helps clinch diagnosis • Lymphoma o Lymphoreticular neoplasms with wide variety of specific diseases & cellular differentiation o Protean variable imaging manifestations • Leukemia o White blood cell neoplasia with spinal involvement as component of systemic disease o Abnormal enhancement of marrow, focal lesion, or leptomeninges on CECT and MR o Diffuse osteopenia with multiple vertebral fractures ± lytic spine lesions helps suggest disease in context of intradural enhancement • Chemical Meningitis o Nonspecific smooth (not nodular) enhancement of intradural nerve roots in correct clinical context o Often see some enhancement of conus pia

INTRADURAL/EXTRAMEDULLARY,LEPTOMENINGEAL ENHANCEMENT o

May persist after causative agent removed, but should gradually return to normal signal on follow-up studies

Helpful Clues for Rare Diagnoses • Sarcoidosis o Noncaseating granulomatous disease of spine and spinal cord o Protean imaging manifestations mimic multiple spinal pathologies • Invariable presence of systemic disease helps make diagnosis and avoid biopsy • Arachnoiditis, Lumbar o Post-inflammatory adhesions + clumping of nerve roots o Best diagnostic clue is absence of discrete nerve roots within thecal sac ("empty sac sign") • Nerves are adhesed to wall of thecal sac, dural margins enhance o Evidence of prior lumbar surgery helps suggest diagnosis • Hypertrophic Neuropathy o Hereditary disorder characterized by focal or diffuse peripheral nerve enlargement o Fusiform peripheral nerve mass(es) ± enlarged cauda equina nerve roots • Anterior Radiculopathy Syndrome o Chemotherapy-related anterior nerve root enhancement associated with intrathecal methotrexate treatment • Progressive paraparesis after intrathecal methotrexate administration followed by complete or partial recovery

Guillain-Barre

Sagittal TI

C+

MR shows

Avid enhancement without nodularity of anterior spinal cord pia and ventral lumbosacral nerve roots • CIDP o Characterized by relapsing or progressive muscle weakness ± sensory loss o Focal or diffuse fusiform enlargement and abnormal T2 hyperintensity of cauda equina, nerve roots/plexi, and peripheral nerves o Lumbar> cervical, brachial plexus, thoracic/intercostal> cranial nerve o Both spinal nerve roots and peripheral nerves (extraforaminal > intradural) involved • Malignant Peripheral Nerve Sheath Tumors o Malignant tumor of neural sheath origin involving spinal root, neural plexus, peripheral nerve, or end organs o Large infiltrative, often hemorrhagic, soft tissue mass anatomically related to neurovascular bundle o Paravertebral, rarely intraspinal o

Other Essential Information • Diverse etiologies necessitate close clinical correlation to make a specific diagnosis

Syndrome

diffuse smooth

linear

enhancement of the conus pia and cauda equina nerve roots.

Sagittal TI

C+

MR demonstrates multiple

nodular

leptomeningeal enhancing metastatic tumor deposi15

II 6

(intracranialoligoaslrocyloma).

9

INTRADU

RAL/EXTRAMEDU

LLARY, LEPTOMEN ING EAL EN HANCEMENT

Ependymoma, Myxopapillary, Spinal Cord (Left) Axial demonstrates enhancement

Ql

r:: Co

en

n

C+ FS MR smooth linear of conus pia

and cauda equina nerve roots. The CSF shows slightly higher signal intensity than normally expected for CSF,

suggesting proteinaceous conten!. CSF should have signal intensity similar to other simple fluids on MR imaging; variation from this merits Further evaluation. (Right) Sagiual T1 C+ MR shows copious intradural enhancing tumor filling the distal thecal sac.

Neurofibroma

Schwannoma

(Left) Sagittal T1 C+ MR shows nodular enhancing neurofibromas within the conus leptomeninges and the cauda equina. The diagnosis was neurofibromatosis

type

1.

(Right) Sagiual T1 C+ MR shows diffuse leplOmeningeal enhancement and innumerable small schwannomas in the cauda equina. The diagnosis was neurofibromatosis

type 2.

lymphoma (Left) Sagiual T1 C+ MR shows diffuse nodular leptomeningeal enhancement following intrathecal dissemination of Burkiu lymphoma. (Right) Axial T1 C+ MR shows enhancing intradural lymphoma metastases along the leplOmeninges, surrounding the distal conus and diffusely involving the nerve roots.

II 6 10

I NTRADU

RAlIEXTRAMEDU

LLARY, LEPTOMEN I NGEAL EN HANCEMENT

(Left) Sagittal T1 C+ MR conFirms diFFuse leptomeningeal enhancement

from

disseminated intrathecal leukemic metastasis encircling the spinal cord and inFiltrating the cauda equina. (Right) Sagitlal T I C+ MR shows diffuse leptomeningeal enhancement, representing chemical meningitis in a aneurysmal subarachnoid hemorrhage patient. T1 WI MR beFore contrast (not shown) demonstrated no T1 shortening.

Sarcoidosis (Left) Sagittal T1 C+ MR shows diFFusenodular enhancing coating of the conus leptomeninges and cauda equina. (Right) Sagittal T1 C+ MR shows diFFuseenhancement of ventral conus pia and cauda equina

(anterior

radieulopathy syndrome). Leptomeningeal tumor dissemination may produce an identical imaging appearance to other disseminated metastases.

csr

Malignant

Peripheral Nerve Sheath Tumors

rs

(LeFt) Sagittal T1 C+ MR demonstrates variant striking diFFusepial and cauda equina

nerve rool

enhancement. Axial T2WI MR images (not shown) confirmed peripheral nerve enlargement. (Right) Sagittal T1 C+ MR shows a nodular neuroFibroma along the dorsal conus and extensive enhancement of the distal leptomeninges and thecal sac From metastatic MPNST (NFl).

II 6

INTRADURAL/EXTRAMEDULLARY LESION, NO ENHANCEMENT

DIFFERENTIAL DIAGNOSIS Common • Filum Terminale Fibrolipoma • CSF Flow Artifact • Arachnoid Cyst Ql

C Co

en

Less Common • Subarachnoid Hemorrhage • Conjoined Nerve Roots • Dermoid and Epidermoid Tumors • Epidermoid Tumor, Acquired • Meningioma (Calcified) Rare but Important • Neurenteric Cyst • Arachnoiditis, Lumbar • ClOP

• Hypertrophic

Neuropathy

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Clinical correlation permits more specific diagnosis Helpful Clues for Common Diagnoses • Filum Terminale Fibrolipoma o Linear fat signal in filum terminale, normal conus position • CSF Flow Artifact o Tl hyperintense, T2 hypointense com pared to CSF o Cannot confirm in exactly same place on orthogonal imaging planes • Arachnoid Cyst

Filum Terminale

II 6 12

o

CSF signal on T1WI, ~ CSF signal on T2WI

Helpful Clues for Less Common Diagnoses • Subarachnoid Hemorrhage o Variable appearance depending upon clot formation, blood product age • Conjoined Nerve Roots o Aberrant root sleeve containing 2 nerve roots • Dermoid and Epidermoid Tumors o Lumbosacral or cauda equina CSF signal mass ± diffusion restriction (epidermoid) • Epidermoid Tumor, Acquired o Iatrogenically implanted epithelial elements (prior lumbar puncture with nonstyletted needle) • Meningioma (Calcified) o Hypointense on Tl WI, T2WI; calcifications obscure enhancement Helpful Clues for Rare Diagnoses • Neurenteric Cyst o Intraspinal cyst lined by enteric mucosa ± vertebral anomalies • Arachnoiditis, Lumbar o Post-inflammatory adhesion & clumping of intrathecal nerve roots o May not perceive discrete nerves because adhesed to dural sac • CIDP

Focal/diffuse fusiform nerve enlargement, abnormal T2 hyperintensity • Hypertrophic Neuropathy o Fusiform peripheral nerve ± cauda equina mass(es) o

Fibrolipoma

CSF Flow Artifact

=

Sagittal T7WI MR demonstrates linear high signal

Sagillal

intensity wi!hin cauda equina, reflecting typical pallern

arachnoid cYSt~

of ("tty infiltration by fibrolipoma.

thecal sac dorsal to the spinal cord, caused by altered (Jow dynamics.

T7WI MR in a padent

with

an epidural

shows CSF flow artifact

in !he

INTRADURAL/EXTRAMEDULLARY

LESION,

NO ENHANCEMENT

Arachnoid Cyst

rs

(Left) Sagillal T7 C+ MR reveals a large CSF signal arachnoid

cyst, centered

in

epidural fa/, producing dorsal mass effecl on the dura and spinal cord. There is no cyst wall enhancement.

(Right) Sagillal T7 C+ MR demonslrales diffuse, slightly increased CSF signal intensity within the thecal sac, reflecting

proteinaceous

debris. There is no abnormal intradural enhancement.

Conjoined Nerve Roots (Left) Sagillal TI C+ FS MR shows two nonenhancing nerve roots in Ihe left LS

=

neural foramen. Enhancement foramina

in the

above and below

the L5 level reflect enhancement within the dorsal rool ganglia. (Right) Sagittal T I C+ MR sho\Vs irregular CSF signal architectural

distortion

of the

cauda equina nerve roots without abnormal enhancement,

representing

an epidermoid that was acquired after lumbar puncture.

Hypertrophic Neuropathy (Left) Sagillal T7 C+ MR demonstrates a large ventral neurenteric cyst, producing

spinal cord compression. There was no enhancement

of the cyst wall, and no associated vertebral

anomalies were detected. (Right) Axial TlWI MR demonstrates diffuse enlargement of the intradural cauda equina nerve roots. Imaging slices taken more caudally (not shown) also showed bilateral extradural peripheral nerve enlargement

II 6 13

INTRADURAL/EXTRAMEDULLARY

DIFFERENTIAL DIAGNOSIS

Ql

c: "ii

en

Common • Solid Mass o Schwannoma o Meningioma o Neurofibroma o Ependymoma, Myxopapillary, Spinal Cord • Leptomeningeal o Metastases, CSF Disseminated o Post Chemo/Radiation Therapy Nerve Enhancement Less Common • Leptomeningeal o Leukemia o Lymphoma o Guillain-Barre Syndrome o Meningitis, Spinal o Sarcoidosis Rare but Important • Solid Mass o Paraganglioma o Malignant Nerve Sheath Tumors • Leptomeningeal o Hypertrophic Neuropathy oCIDP o CMV Radiculopathy o Anterior Lumbar Radiculopathy Syndrome o Metachromatic Leukodystrophy (MLD) o P ET

ESSENTIAL INFORMATION

II 6 14

LESION, SOLID ENHANCEMENT • Neurofibroma o Localized (90%), diffuse, and plexiform (pathognomonic for NFl) nerve sheath neoplasms o Multilevel nerve root and paraspinal tumors ~ neurofibromatosis type 1 • Ependymoma, Myxopapillary, Spinal Cord o Occurs almost exclusively in conus, filum terminale, cauda equina o Enhancing cauda equina mass with hemorrhage o Usually spans 2-4 vertebral segments; may fill entire lumbosacral thecal sac • Metastases, CSF Disseminated o Spread of malignant tumors through the subarachnoid space o Smooth/nodular enhancement distributed on cord surface and nerve roots • Post Chemo/Radiation Therapy Nerve Enhancement o Nonspecific smooth (not nodular) enhancement of intradural nerve roots ± conus pia o May persist after therapy completed, but should gradually return to normal signal on follow-up studies Helpful Clues for Less Common Diagnoses • Leukemia o Abnormal enhancement of leptomeninges on CECT and MR o Look for diffuse osteopenia, multiple vertebral fractures ± lytic spine lesions to suggest diagnosis • Lymphoma o Protean imaging manifestations; nodular leptomeningeal metastases rare • Guillain-Barre Syndrome o Autoimmune post-infectious or post-vaccinial acute inflammatory demyelination of peripheral nerves, nerve roots, cranial nerves o Smooth pial enhancement of the cauda equina and conus • Meningitis, Spinal o Infection of spinal cord leptomeninges and subarachnoid space o Smooth or irregular meningeal enhancement ± CSF enhancement, abnormal CSF signal intensity ("dirty CSF") • Sarcoidosis

INTRADURAl/EXTRAMEDULLARY o

o

Combination of leptomeningeal and peripheral intramedullary mass-like enhancement Invariable presence of systemic disease helps make diagnosis and avoid biopsy

Helpful Clues for Rare Diagnoses • Paraganglioma o Well-defined intradural extramedullary vascular mass with prominent flow voids, intense enhancement o Cauda equina > > cervical, thoracic spine • Malignant Nerve Sheath Tumors o Malignant nerve sheath tumor involving spinal root, neural plexus, peripheral nerve, or end organs o Large circumscribed infiltrative enhancing mass ± hemorrhage • Hypertrophic Neuropathy o Hereditary disorder characterized by focal or diffuse peripheral nerve ± cauda equina enlargement o Distal extremity atrophy ± abnormal muscle Tl hyperintensity, volume loss (chronic denervation - fatty atrophy) • CIDP o Enlargement and abnormal T2 hyperintensity of nerve roots, plexi, or peripheral nerves o Lumbar> cervical, brachial plexus, thoracic/ intercostal> cranial nerve • CMV RadicuIopathy o Immunosuppressed AIDS patients

Sagillal Tl c+ MR demonslrales a large homogeneous inlradural mass Ihal fills the spinal canal and displaces the spinal cord in a paUent with path-proven schwannoma.

LESION, SOLID ENHANCEMENT Smooth pial enhancement of the conus, cauda equina o onenhanced MR imaging is frequently normal - routine contrast administration recommended in AIDS patients • Anterior Lumbar Radiculopathy Syndrome o Chemotherapy-related anterior spinal cord pia and ventral nerve root enhancement following intrathecal methotrexate treatment • Metachromatic Leukodystrophy (MLD) o Autosomal recessive deficiency of lysosomal enzyme arylsulfatase A o Nonspecific contrast enhancement of cauda equina nerve roots o Specific diagnosis suggested by characteristic brain findings • PNET o Primary leptomeningeal origin of PNET tumor o Nodular enhancement of cauda equina, leptomeninges o

Sagittal Tl C+ FS MR reveals an intradural mass lesion wilh avid mass enhancemenl and flallened base EE suggesting dural attachment producing compression of adjacent spinal cord.

II 6 15

INTRADURAL/EXTRAMEDULLARY

LESION,

SOLID

ENHANCEMENT

Ependymoma, (Left) Sagittal T1 C+ MR shows a typical appearance o( solitary intradural cauda equina neurofibroma (Right) Sagittal T' C+ MR reveals a mass within the thecal sac, obscuring the conus termination and cauda

=.

Ql

c: a.

rtl

equina. Note the avid homogeneous

tumor

enhancement.

Metastases, (Lefl) Sagittal T' C+ MR shows nodular enhancing leptomeningeal "drop" metastases from intracranial oligoastrocytoma. (Right) Sagittal T1 C+ MR demonstrates abnormal nodular cauda equina infiltration. The cauda equina nerve roots are abnormally thickened with diffuse leptomeningeal enhancement caused by disseminated intrathecal leukemic metastasis encircling the conus and infiltrating the cauda equina.

=

(Left) Sagittal T1 C+ MR shows extensive enhancing leptomeningeal metastases in this patient with non-Hodgkin lymphoma. (Rig/") Sagittal T' C+ MR shows mild thickening and avid enhancement of the ventral motor roots of the cauda equina and conus pia

=.

II 6 16

CSF Disseminated

Myxopapillary, Cord

Spinal

INTRADURAL/EXTRAMEDULLARY

LESION,

SOLID

ENHANCEMENT

Sarcoidosis (Lefl) Sagillal T7 C+ MR demonstrates diffuse leptomeningeal enhancement along the cervical spinal cord extending up into the posterior fossa E±. (Rig"l) Sagittal T I C+ MR shows multiple enhancing subarachnoid nodules interspersed among the cauda equina and studding the conus pia.

Malignant

Nerve Sheath Tumors

rs

(Lefl) Sagittal T I C+ MR shows a small enhancing intradural nodular mass nestled within the cauda equina with avid mass enhancement typical of paraganglioma. (Rigllt) Sagillal T I C+ MR in a patient wit" NFl shows a nodular neurofibroma along the dorsal conus and extensive enhancement of the distal leptomeninges and thecal sac from metastatic malignant nerve sheath tumor.

=

C1DP

(MV Radiculopathy (Lefl) Sagittal T7 C+ FS MR demonstrates striking diffuse pial and cauda equ;na nerve root enhancement. Other images (not shown) confirmed peripheral nerve enlargement (RighI) Sagittal T7 C+ MR shows irregular cauda equina nerve rool

enhancement secondary to CMV polyradiculopathy. Nonenhanced MR imaging (not shown) was normal.

II 6 17

INTRADURAL

~ co

LESION,

SERPENTINE

:::J

"0 Q)

E

co ~ X

UJ

...!.

co ~ :::J

"0

co ~ C C1l

c: Co

l/l

DIFFERENTIAL DIAGNOSIS Common • CSF Flow Artifact • Vascular Malformation, Type 1 • Vascular Malformation, Type 2 • Redundant Roots due to Thecal Sac Compression a Central Stenosis a Herniation (Uncommon) Less Common • Tumor Feeding Vessels a Hemangioblastoma, Spinal Cord a Ependymoma, Myxopapillary, Spinal Cord a Paraganglioma a Schwannoma • Hereditary Motor/Sensory Neuropathy • Collateral Veins/IVC Occlusion • Vascular Malformation, Type 3 • Vascular Malformation, Type 4 • Brain Dural A-V Fistula

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • CSF Flow Artifact a Related to both time-of-flight (TOF) effects and turbulent flow • TOF signal loss seen with SE or FSE when protons do not experience both initial RF pulse and subsequent refocusing pulse • Increased signal loss with higher flow velocity, thin slices, longer TE, imaging perpendicular to flow CSF Flow Artifact

• GE imaging less susceptible to CSF flow artifacts • Turbulent flow leads to more rapid proton dephasing with signal loss a Repeat study with different plane of imaging, and GE sequences with short TE • Vascular Malformations a Most common is type 1 dural fistula • Lesions are extramedullary AVFs, not true AVMs • Venous drainage from the DAVF results in increased pial vein pressure that is transmitted to intrinsic cord veins • Venous hypertension from engorgement reduces intramedullary AV pressure gradient, causing reduced tissue perfusion & cord ischemia • Hallmark is T2 hyperintense cord (usually distal thoracic), intradural flow voids on cord surface, esp. dorsal • Redundant Roots due to Thecal Sac Compression a Seen with severe central canal stenosis or, much less commonly, large herniation a Typically seen cephalad to level of severe stenosis Helpful Clues for Less Common Diagnoses • Tumor Feeding Vessels a Associated with vascular tumor such as ependymoma or hemangioblastoma a Look for primary enhancing soft tissue mass

Vascular Malformation,

Type 1

II 6 18

Sagillal T2WI MR shows extensive normal CSF flow dephasing that involves the dorsal subarachnoid space

=

=.

Sagittal T2WI MR shows typical serpentine flow voids on dorsal aspect of thoracic cord with T2

hyperintensity within distal thoracic cord (venous hypertensive edema).

INTRADURAL

LESION,

Ependymoma, Central Stenosis

SERPENTINE

Myxopapillary, Cord

Spinal (Left) Sagittal T2WI MR shows severe stenosis with disc bulging producing extensive nerve root redundancy seen al mulliple serpentine low signal rools of the cauda equina within lhecal sac 81. (Right) Sagitlal T2WI MR shows intradural tumor that has prominent feeding serpentine vessels 81.

=

=

Hereditary

Motor/Sensory

Neuropathy

Collateral

Veins/IVC Occlusion (Left) Sagitlal T2WI MR

shows a case of Charcol-Marie-Tooth with diffuse enlargement of the intradural cauda equina nerve roots. The conus is normal. (Right) Sagittal T2WI MR shows chronic inferior vena cava occlusion E:I with intradural collateral venous drainage in the lumbar spine

=

Vascular Malformation,

Type 4

Brain Dural A-V Fistula (Left) Sagittal T2WI MR shows multiple prominent flow voids within subarachnoid space and involving cervical cord from lhis eXlensive AVM. (Right) Sagittal T2WI MR shows multiple flow voids on cervical cord surface 1:1 wilh diffuse cord T2 hyperintensity. There is a posterior fossa AV fistula wilh intraspinal drainage 81.

II 6 19

INTRADURAL/EXTRAMEDULLARY LESION, MULTIPLE

DIFFERENTIAL DIAGNOSIS Common • CSF Flow Artifact • Neurofibromatosis Type 1 • Neurofibromatosis Type 2 • Metastases, CSF Disseminated Cl)

c: a.

en

Less Common • Multiple Nerve Sheath Tumors (Multiple, Nonsyndromic) o Schwannoma o Neurofibroma • Meningiomas, Multiple • Type 1 DAVF • Hemangioblastoma, Spinal Cord • Granulomatous Disease Rare but Important • Cysticercosis

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Neurofibromatosis Type 1 o Multiple, enhancing, bulky, fusiform nerve root masses; may be intradural, extradural, or transdural o Associated findings: Extraspinal plexiform neurofibromas, kyphoscoliosis, dural ectasia o Suddenly enlarging or painful lesion: Consider malignant degeneration • Neurofibromatosis Type 2

Neurofibromatosis

II 6 20

Multiple, circumscribed extramedullary masses associated with nerve roots, at any location along the spine or cauda equina • Metastases, CSF_Disseminated o Spread from an extraspinal primary (breast, lung, lymphoma/leukemia) or "drop metastases" from a CNS primary (medulloblastoma, ependymoma, GBM) o Single/multiple dural- or pial-based enhancing nodules; can become confluent, causing a "sugar coated" appearance o

Helpful Clues for Less Common Diagnoses • Multiple Nerve Sheath Tumors (Multiple, Nonsyndromic) o Most common "intradural extramedullary" masses, but non-syndromic lesions are usually solitary o "Target sign", hemorrhage, degeneration all more common with neurofibroma than with schwannoma • Meningiomas, Multiple o Dural-based, intensely enhancing, nearly isointense on Tl WI, variably hyperintense on T2WI o Multiple meningiomas can be seen with type 2 neurofibromatosis Other Essential Information • Extramedullary masses (schwannomas, meningiomas) frequently result in cord compression

Type 1

Sagittal T1 C+ MR shows typical case of muldple

Sagittal T1 C+ MR shows muldple enhancing nodules

enhancing nodules in the cauda equina in this patient

within fibers of tbe cauda equina in this patient with

with neurofibromatosis type 1.

neurofibromatosis type 2.

INTRADURAL/EXTRAMEDULLARY

Metastases, CSF Disseminated

LESION, MULTIPLE

Metastases, CSF Disseminated (Left) Sagittal T I C+ MR shows typical case of drop metastases from a pineal germinoma, with multiple extramedullary masses along the surface of the conus and fibers of the cauda equina. (Right) Sagittal TI C+ MR shows a bulky dural mass compressing the cervicomedullary junction 81 and multiple pial lesions in this patient with small cell lung cancer.

=

Hemangioblastoma,

Spinal Cord (Left) Sagittal T2WI MR shows T2 hyperintensity in the cord (from venous hypertension) and innumerable intradural flow voids along the exterior of the cord in this patient with a dural AV fistula. (Right) Sagittal TI C+ MR shows multiple focal enhancing hemangioblastomas along the dorsal cord surface in this patient with yon Hippel-Lindau. Note lesion in the posterior fossa ~.

=

Cysticercosis (Left) Sagittal TI C+ MR

shows a case of neurosarcoid, revealing multiple enhancing subarachnoid nodules interspersed among the cauda equina and along the pia of the conus. (Right) Sagittal CECT rCT myelogram) shows multiple subarachnoid filling defects, representing cysts from cysticercosis.

II 6 21

INTRADURAL/EXTRAMEDUllARY LESION, RING/PERIPHERAL ENHANCEMENT

DIFFERENTIAL DIAGNOSIS Common • Arachnoid Cyst • Schwannoma (Cystic) • Meningioma (Cystic or Calcified) CI>

r:: Q.

1Il

less Common • Neurenteric Cyst • Meningitis, Spinal Rare but Important • Cysticercosis • Arachnoiditis, Lumbar • Arachnoiditis Ossificans, Lumbar • Echinococcus • Hypertrophic Neuropathy

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Using all available clinical information helps constrain the differential diagnosis list • Status of anatomical structures adjacent to the spinal cord may help suggest the correct diagnosis

II 6 22

Helpful Clues for Common Diagnoses • Arachnoid Cyst o Peripheral enhancing (faint) or nonenhancing (more common) loculated extramedullary CSF intensity fluid collection o Displaces adjacent spinal cord or nerve roots o CSF signal intensity on T1WI MR, ~ CSF signal on T2WI MR • Reflects combination of signal alteration related to cyst proteinaceous content and comparatively. flow related signal loss compared to CSF in thecal sac o Consider FLAIRMR to accentuate signal differences between cyst and CSF (analogous to imaging brain arachnoid cyst) • Schwannoma (Cystic) o Peripheral nervous system nerve sheath neoplasm originating from Schwann cells o Typically originates from dorsal rather than ventral spinal nerve roots o Arises from single nerve fascicle and displaces other adjacent nerve fascicles peri pherall y

• Characteristic mass effect on fascicular pattern on short axis imaging may help distinguish from neurofibroma • Meningioma (Cystic or Calcified) o Slow growing, benign tumor originating from dura mater o Presence of diffuse or focal intraspinal calcification helps suggest a specific diagnosis o Calcified portions may be hypo intense on both T1WI MR and T2WI MR or be relatively inconspicuous Helpful Clues for less Common Diagnoses • Neurenteric Cyst o Intraspinal cyst lined with enteric mucosa o Abdominal or mediastinal location • Ventral> dorsal • Extramedullary (80-85%) > intramedullary (10-15%) • Midline> paramedian o Look for associated vertebral abnormalities (persistent canal of Kovalevsky, segmentation, and fusion anomalies) to help make diagnosis o However, not all neurenteric cysts are associated with vertebral segmentation anomalies however • Meningitis, Spinal o Infection of spinal cord leptomeninges and subarachnoid space cerebrospinal fluid surrounding spinal cord o Best diagnostic clue is diffuse, extensive subarachnoid enhancement of meninges and identification of CSF inflammatory loculations o Additional helpful clues (when present) include "dirty" CSF showing slightly increased Tl & T2 signal intensity or presence of fluid/debris level in terminal thecal sac Helpful Clues for Rare Diagnoses • Cysticercosis o CNS parasitic infection caused by pork tapeworm (Taenia solium) o Thoracic (60-75%) > cervical, lumbar location o May be extraspinal (vertebral body) or intraspinal (extradural, subarachnoid, intramedullary) o Most frequently see multilocular cysts rather than a single cyst

INTRADURAL/EXTRAMEDULLARY LESION, RING/PERIPHERAL ENHANCEMENT

en

"'C ::::J

(l)

• Arachnoiditis, Lumbar a Post-inflammatory adhesions producing clumping of nerve roots a Best diagnostic clue; Nonidentification of discrete nerve roots within thecal sac ("empty sac sign") • Nerves are adhesed to wall of thecal sac • Dural margins enhance a Evidence of prior lumbar surgery or residual intrathecal Pantopaque myelographic contrast helps suggest correct diagnosis • Arachnoiditis Ossificans, Lumbar a Intradural ossification associated with post-inflammatory adhesions and clumping of lumbar nerve roots a Evidence of prior lumbar surgery or residual intrathecal Pantopaque myelographic contrast helps suggest correct diagnosis a Look for focal calcific density on CT or hyperintensity on T1 WI and T2WI within lumbar nerve root aggregate • Echinococcus a Disease caused by cyst stage of echinococcus genus tapeworm infestation a Usually seen in patien ts living in endemic area for echinococcus a Liver, lung involvement are most common a Bone involvement is rare

Arachnoid

Cyst

Axial TI C+ FS MR shows anlerior displacement of lower lhoracic spinal cord =:lI by a fainUy

rim-enhancing posterior intraspinal fluid intensity mass 81.

Best diagnostic clue; Identification of multi loculated, multiseptated T2 hyperintense vertebral body/posterior element mass showing minimal enhancement • Hypertrophic Neuropathy a Hereditary disorder characterized by focal or diffuse peripheral nerve enlargement a Fusiform peripheral nerve mass(es) ± cauda equina nerve roots a ± Abnormal muscle Tl hyperintensity, volume loss (chronic denervation - fatty atrophy) a Best diagnostic clue; Focal or diffuse peripheral nerve enlargement + distal extremity atrophy a

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Q. C

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, m

~ ~ OJ 3

CD

Q. C OJ

-<

Other Essential Information • Using all available clinical information helps to constrain the differential diagnosis list • Pattern of involvement of regional spinal axis structures may also provide useful clues that can help limit diagnosis list • Important to assess for spinal cord compression

Schwan noma (Cystic)

Axial T1 C+ MR shows a wefl-circumscribed ventral

intraspinal mass compressing the spinal cord with intense peripheral enhancement and a centIal cystic nonenhancing region

=-

II 6 23

INTRADURAL/EXTRAMEDUllARY

Gl

c: 0-

m

lESION,

RING/PERIPHERAL

ENHANCEMENT

(Left) Sagittal T1 C+ MR in patient with path-proven meningioma demonstrates an intradural mass at T3-4 producing spinal cord compression. Note avid mass enhancement and small dural taill:J suggesting meningioma. (Right) Axial T1 C+ MR shows a heavily calcified cervical dural-based hypointens€ mass producing spinal cord E!l:I compression. Heterogeneous mass enhancement, eccentricity helps distinguish from severe focal OPLL

=

Neurenteric

Cyst

Meningitis,

Spinal

Spinal

Meningitis,

Spinal

(Left) Axial T1 C+ MR

demonstrates a dorsal complex multilocular extramedullary heterogeneous ring-enhancing mass 1m that produces severe spinal cord compression. No vertebral anomalies were identified in this patient. (Right) Axial T1 C+ MR demonstrates smooth abnormal enhancement of the conus pia and cauda

m

equina nerve roots (confirmed fungal meningitis).

Meningitis, (Left) Axial T1 C+ FS MR shows smooth tinear enhancement of cauda equina nerve roots. CSF shows slightly higher signal intensity than normal, indicating proteinaceous content. (Right) Axial T1 C + MR demonstrates diffuse leptomeningeal enhancement coating cervical spinal cord. This patient was diagnosed with histoplasmosis and successfully treated with antifungal medication.

II 6 24

INTRADURAL/EXTRAMEDULLARY

Cysticercosis

LESION,

RING/PERIPHERAL

ENHANCEMENT

Cysticercosis (Left) Axial TI C+ MR reveals a {ocal cystic mass within the distal thoracic spinal canal producing fusiform spinal cord expansion and demonstrating mild cyst wall enhancement. (Right) Sagiual TI C+ MR shows a cystic and solid ring-enhancing mass that produces severe spinal cord

=

compression and secondary involvement of the upper cervical cord.

Arachnoiditis,

Lumbar

Arachnoiditis

Ossificans,

Lumbar (Left) Axial TI C+ MR depicts thickened and

clumped nerve

rOOlS

=

within the central aspect of thecal sac related 10 arachnoiditis. Note prior lamineclOmy defect, suggesting source of arachnoiditis. (RighI) Axial NECT in patient with myxopapil/ary ependymoma (tumor not shown) shows J;near dural calcification Ossifying arachnoiditis is secondary to tumoral post-hemorrhagic inflammation.

=.

Echinococcus

Hypertrophic

Neuropathy (Left) Coronal TlWI MR depicts multicystic echinococcus lesions. The large complex cystic mass extends through the paravertebral region into the epidural space E2 and compresses the thecal sac. (Right) Axial TlWI MR depicts moderate abnormal enlargement of the intradural cauda equina nerve roots. There was also abnormal enlargement of extradural peripheral nerves in the lower extremities (not shown) of this patient with Charcot-Marie-Tooth.

II 6 25

INTRADURAL/EXTRAMEDULLARY LESION, 11 HYPERINTENSE

DIFFERENTIAL DIAGNOSIS

Ql

c: a.

m

Common • Metal Artifact • Filum Terminale Fibrolipoma • Lipoma • Subdural Hematoma • Subarachnoid Hemorrhage • Lipomyelomeningocele Less Common • Dermoid and Epidermoid Tumors • Melanoma Metastasis • Pantopaque Rare but Important • Melanotic Schwan noma • Melanocytoma

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Metal Artifact o MR '* geometric distortion + signal loss secondary to dephasing o Minimize with FSE, larger FOY, higher bandwidth, small voxel, orientation of frequency encode direction o Minimize pedicle screw artifact by orienting frequency encode gradient parallel to screw long axis, using FSE technique • Filum Terminale Fibrolipoma o Tl WI shows small linear focus of fat, with normal conus position and morphology

Incidental in 4-6% of autopsy subjects Intraspinal lipoma if larger lesion and filum> 2 mm in thickness • Lipoma o Spinal lipoma intimately associated with dorsal spinal cord (intradural) or distal cord/filum insertion (terminal) o Hyperintense (Tl WI) intradural mass o Use frequency selective fat suppression if unsure of composition of hyperintense mass • Subarachnoid Hemorrhage o Intradural collection hyperintense on Tl WI, predominantly hypointense on T2WI or gradient-echo imaging o Subarachnoid shows fluid-fluid level o Subdural shows well-defined outer dural margin, lobulated inner margin • Lipomyelomeningocele o Subcutaneous fatty mass contiguous with neural placode/lipoma via posterior dysraphism o Cord always tethered o Cutaneous stigmata (50%); hemangioma, dimple, dermal sinus, skin tag, hairy patch o

o

Helpful Clues for Less Common Diagnoses • Dermoid and Epidermoid Tumors o Epidermoid '* nonenhancing, CSF signal-like intradural mass within cauda equina • Look for dermal sinus association o Dermoid shows heterogeneous mass with mixed signal (fat)

Metal Artifact

II 6 26

Sagittal T1WI MR shows two level fusion from C3 to CS with metal artifact from screws Screw artifact at C5 level extends to the ventral epidural space adjacent to thecordSl.

=.

Sagittal T1WI MR shows fine linear region of T1 hyperintensity

along

the filum

The conus is normal in position.

terminale

due to fat

1m.

INTRADURAL/EXTRAMEDULLARY

Lipoma

LESION, 11 HYPERINTENSE

CIl "t:l ::::J CD

Subdural Hematoma (Left) Sagittal T7 WI MR shows lumbar skin dimple with dermal sinus tract containing a small dermoid t:21 The low-lying spinal cord is affixed to a dorsal intradural lipoma SII. (Right) Axial T7WI MR shows Ihe subdural location of the hemorrhage, with an intact

=

Dermoid

and Epidermoid

curvilinear

outer dural

margin lobulated

and a typical inner margin.

Tumors (Left) Sagillal T7 WI MR shows telhered cord that terminates into a lipomatous mass I:lJ atlhe L4-S level, and a dorsal bony dysraphism. (Right) Axial TI WI MR shows a large dermoid

tumor

=

with T I

hyperintensity and a well-defined lobulated contour.

Pantopaque

Melanotic

Schwannoma (Left) A,ial T1WI MR shows a focal high signal wilhin distallhecal sac due 10 prior Pantopaque myelography

m.

Note changes of prior

laminectomy. (Right) Sagillal T7 WI MR shows a varianl case of an intradural extramedullary schwannoma involving the lumbar nerve rools wilh high signal seen on pre-contrast T I

=

images due to melanin.

II 6 27

INTRADURAL/EXTRAMEDULLARYLESION, 11 HYPOINTENSE

CI)

c: a.

CJ)

Common • CSF Flow Artifact • Post-Operative Intrathecal Gas • Metal Artifact • Arachnoid Cyst • Epidermoid • Meningioma, Calcified • Schwan noma, Cystic • Vascular Malformation Less Common • CSF Disseminated Metastases • Displaced Cord with Prominent Adjacent CSF o Spinal Cord Herniation o Arachnoiditis/Adhesion o Post-Traumatic Pseudomeningocele • Arachnoiditis Ossificans • Cysticercosis • Ependymoma, Myxopapillary (Calcified) • Glioma, Exophytic

•

•

Rare but Important • eurenteric Cyst •

ESSENTIAL INFORMATION

II 6 28

Helpful Clues for Common Diagnoses • CSF Flow Artifact o Linear or rounded low signal with ill-defined margins surrounding cord due to normal CSF motion o Typically most prevalent in dorsal thoracic spine o Include axial GE images to minimize artifact and exclude vascular flow voids • Metal Artifact o Geometric distortion and signal loss secondary to dephasing o Tl images show focal central signal loss with peripheral "halo" of t signal related to spatial mismapping o Image quality: Fast spin echo> conventional spin echo < gradient echo o Smaller voxel size, lower field strength decrease artifact amount o Appropriate geometric orientation of frequency encode direction parallel to pedicle screws shows thecal sac best

• Arachnoid Cyst

Nonenhancing extramedullary loculated CSF intensity collection displacing cord or nerve roots o May be suggested by mass effect on cord and nerve roots without direct wall visualization o Partial filling of cyst may occur with CT myelography, with wind-sock type Epidermoid o Nonenhancing intradural mass similar to CSF intensity within cauda equina o Should not track CSF on all pulse sequences, as would arachnoid cyst o Should not enhance, unless complicated by infection o If lumbar in child, look for associated dermal sinus track Meningioma, Calcified o Enhancing intradural/extramedullary mass and dural tail o Calcified lesions may show little enhancement, very low Tl/T2 signal o May show target pattern with central calcification, peripheral homogeneous tumor enhancement Schwannoma, Cystic o Well-circumscribed, dumbbell-shaped, enhancing spinal mass o May be solid, yet show Tl homogeneous hypointensity o Tl hypointensity may also reflect cyst formation Vascular Malformation o Serpentine flow voids with well-defined margins o Variable pattern depending upon type (fistula vs. AVM) and location (cord vs. pial vs. transpatial) o Most common is type 1, with vessels on dorsal cord surface with cord T2 hyperintensity due to venous hypertension o

DIFFERENTIAL DIAGNOSIS

•

Helpful Clues for Less Common Diagnoses • CSF Disseminated Metastases o Smooth/nodular enhancement along cord, roots is best clue o Without contrast, leptomeningeal mets may show ill-defined cord & cauda with "dirty" CSF appearance • Spinal Cord Herniation o Herniation of spinal cord through defect in dura of ventral canal

INTRADURAL/EXTRAMEDULLARY

Focal anterior displacement of cord with expansion of dorsal subarachnoid space in upper thoracic spine o Distinguish from posterior arachnoid cyst by more abrupt cord deformity with idiopathic herniation Arachnoiditis/Adhesion o Focal tethering of cord to dura from prior surgery, infection, or SAH o Shown by distortion of location and morphology of cord within thecal sac o May be associated with arachnoid cysts, superficial siderosis, cord edema Post-Traumatic Pseudomeningocele o CSF collection typically associated with upper cervical fracture (odontoid) with ventral CSF collection and displacement of cord posteriorly o Multisegmental posterior displacement of cervical cord in face of significant cervical trauma o Distinguish from acute epidural hemorrhage that shows isointense Tl signal, heterogeneous T2 signal Arachnoiditis Ossificans o Uncommon presentation of arachnoiditis due to prior trauma, lumbar surgery, subarachnoid hemorrhage, myelography, spinal anesthesia o End-stage arachnoiditis with diffuse or nodular low signal on all pulse sequences involving dura and cord surface, cauda equina Cysticercosis

o

•

•

•

•

Metal Artifact

=.

CNS parasitic infection caused by pork tapeworm, Taenia soli urn o Intradural cyst with evidence of similar lesions in brain most helpful clue o Parenchymal, leptomeningeal, intraventricular, spinal form with cyst size up to 2 cm • Exophytic Intramedullary Tumor o Solid exophytic component may mimic !D/EM lesion o Look for contiguous extension into cord on sagittal/axial planes o Contrast enhancement may show contiguous nature of intramedullary mass o

Helpful Clues for Rare Diagnoses

• Neurenteric Cyst o Intraspinal cyst and vertebral abnormalities o Focal osseous canal enlargement, widening of interpedicular distance o Complex signal transpatial mass with cord deformity o Smaller versions may show Tl hyperintensity at Cl-2 junction

Arachnoid

Sagittal TI WI MR shows two level fusion from C3 to C5 with metal arUfact from screws

LESION, T1 HYPOINTENSE

Screw artifact at C5

level extends to the ventral epidural space adjacent to cord8l. Note congenital fusion at C6-7.

Cyst

Axial TlWI MR shows typical case of intradural arachnoid cyst wilh CSF signal displacing /he cord posteriorly.

=

II 6 29

INTRADURAL/EXTRAMEDULLARY

LESION, 11 HYPOINTENSE

Epidermoid (Lefl) Sagiltal TI WI MR demonstrates a hypo;ntense intradural mass nestled within the cauda equina that displaces adjacent nerve roots. (RighI) Axial TlWI MR shows epidermoid as rounded hyperintensity centrally within the thecal sac, displacing roots to the periphery.

=

Ql

s:: a.

en

(Lefl) Axial TI C+ MR shows variant case a heavily calcified cervical meningoma I:] displacing cord to the left with severe cord compression ~. (RighI) Axial NfCT shows densely calcHied meningioma I::] filling the cervical thecal sac, with displacement of the cord to the left.

or

Schwannoma, (Left) Sagiltal TlWI MR shows subtle low signal mass caudal to the conus medullaris, hypointense to the cord 1:]. (RighI) Sagiltal TI C+ MR shows ID/[M mass with slightly

heterogeneous

but intense

enhancement 1:]. Solid and mixed solid/cystic masses may show quite low T 1

signal.

II 6 30

Cystic

Schwannoma,

Cystic

INTRADURAL/EXTRAMEDULLARY

LESION, 11 HYPOINTENSE

CSF Disseminated

Metastases (Left) Sagittal T1WI MR shows multiple intradural flow voids (rom dural fistula with intraspinal drainage (RighI) SagilLal T1WI MR shows disseminated

=.

leptomeningeal

metastasis as

ill-defined low T1 signal, with obscuration of the normal

cauda equina.

Arachnoiditis/Adhesion (Lefl) Sagittal T IWI MR shows typical case of cord herniation

demonstrating

focal cord thinning and ventral kinking Primary differential for this case is posterior arachnoid cyst vs. cord herniation. (RighI) Sagittal T1 C+ MR shows posterior displacement of the cervical cord I:] with ventral angulation at thoracic junction due to prior SA/-! and subsequent

=.

=.

arachnoiditis.

Neurenteric

Cyst (Left) Sagittal T1WI MR in a patient with type I odontoid (racture shows pronounced CSF signal collection anterior to the cervical cord with generalized posterior cord displacement. (RighI) Sagittal T1WI MR shows mediastinal enteric cyst I:] communicating with a contiguous spinal canal neurenteric cyst E:I. The mediastinal enteric cyst extends into the ventral spinal canal through a patent canal of Kovalevsky.

=

II 6 31

INTRADURAL/EXTRAMEDULLARYLESION, 11 HYPO, 12 HYPO

DIFFERENTIAL DIAGNOSIS

Cl>

c a.

l/l

Common • CSF Flow Artifact • Post-Operative Change, Normal • Metal Artifact • Vascular Malformation • Meningioma, Calcified Less Common • Ependymoma, Myxopapillary (Calcified) • Arachnoiditis Ossificans • Superficial Siderosis

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • CSF Flow Artifact o Related to both time-of-flight (TOF) effects and turbulent flow • Turbulent flow => more rapid dephasing with signal loss • TOF signal loss seen with SE or FSEwhen protons do not experience both initial RF pulse and subsequent refocusing pulse • Increased signal loss with higher flow velocity, thin slices, longer TE, imaging perpendicular to flow • Gradient echo imaging less susceptible to CSF flow artifacts o Repeat study with different imaging plane, GE sequences with short TE • Post-Operative Change, Normal o Most common will be small foci of gas from violation of dura

II 6 32

• Metal Artifact o Fast spin echo better than conventional spin echo better than gradient echo o Use larger field of view o Appropriate geometric orientation of frequency encode direction • Parallel to pedicle screws • Vascular Malformation o Most common is type 1 dural fistula o Hallmark is T2 hyperintense cord (usually distal thoracic), intradural flow voids (especially dorsal) • Meningioma, Calcified o Well-defined ID/EM lesion with dural base o Generally low T2 signal o Solitary lesion, except with F2 Helpful Clues for Less Common Diagnoses • Ependymoma, Myxopapillary (Calcified) o Well-defined enhancing cauda equina mass with evidence of prior hemorrhage • Arachnoiditis Ossificans o Intradural ossification associated with post-inflammatory adhesion and clumping of lumbar nerve roots o Low signal thickened dura and roots • Superficial Siderosis o SAH (multiple etiologies) causing hemosiderin deposition on cord, nerve surface o Diffuse hypointensity of cord surface on T2WI, GE

CSF Flow Artifact

Metal Artifact

Sagillal STIR MR shows prominent signal loss involving the CSF throughout the cervical and upper thoracic spine =::1 related to CSFpulsation and flow dephasing.

Axial T2 GRE MR shows Up of Baclafen delivery catheter to the left of the upper thoracic cord =::1.

INTRADURAl/EXTRAMEDULLARY

(Jl

LESION, 11 HYPO, 12 HYPO

~. :J CD

(Lefl) Sagittal T2WI MR shows multiple IDIEM flow voids with cord hyperintensity & expansion from C 1-4 in this case of posterior fossa dural fistula ~ with cervical venous drainage. (RighI) Lateral angiography shows intradural draining veins E2. This mimics the pallern of type 1 fistula, but hypertensive myelopathy

=

was caused by posterior fossa fistula shunting.

Meningioma,

=

with spinal

Calcified (Lefl) Sagittal T2WI MR shows a thoracic IDIEM mass with a central low signal (calcification)

11Im

displacing the cord posteriorly 81. (RighI) Sagittal T2WI MR shows a broad dural-based hypointense calcified meningioma producing

=

spinal cord compression.

Arachnoiditis Ossificans (Left) Axial T2WI MR shows peripheral low signal surrounding a distal thecal

sac due to thickened and calcified dura from severe arachnoiditis (Rig"') Sagittal T2WI MR shows a typical case of superficial siderosis with hypointense deposilion along the entire cord surface

=.

=.

II 6 33

INTRADURAL/EXTRAMEDULLARY LESION, 12 HYPER, T1 ISO

DIFFERENTIAL DIAGNOSIS

Cll

s:: Q.

l/)

Common • Schwannoma • Neurofibroma • Epidermoid • Ependymoma • CSF Disseminated

Metastases

Less Common • Cysticercosis • Tuberculoma • Sarcoidosis • Meningioma Rare but Important • Paraganglioma • Capillary Hemangioma • Neurenteric Cyst • Echinococcus

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Schwannonla o Well-circumscribed, dumbbell-shaped, enhancing spinal mass o 30% of primary spine tumors o 75% T2 hyperintense o Solitary unless part of inherited tumor syndrome, such as NF2 o Scan entire spine in asymptomatic patients with suspected neurofibromatosis type 2 • Neurofibroma

Schwannoma

II 6 34

Sagillal T2WI MR shows a sharp margin of rounded schwannoma m involving the cauda equina as a T2 hyperintense mass and displacing the fOOts of cauda posleriorly

=.

Bulky multilevel spinal nerve root tumors in patient with NFl o Rapid growth of NF suggestive of malignant transformation o Target sign suggestive of neurofibroma •• peripheral high signal, central lower signal • Epidermoid o Nonenhancing intradural mass similar to CSF signal on T2/Tl images • Ependymoma o Myxopapillary type within caudal sac may show near iso T1 signal, T2 hyperintensity o Large fraction (20-30%) may show little enhancement • CSF Disseminated Metastases o Look for "dirty" CSF appearance on T1, with indistinct cauda and conus o Diffuse or nodular enhancement along cauda equina o

Helpful Clues for Rare Diagnoses • Capillary Hemangioma o Benign tumor of endothelial cell origin o T2 hyperintense enhancing well-defined intradural mass o May be indistinguishable from meningioma or schwannoma • Neurenteric Cyst o Intraspinal cyst and vertebral abnormalities o Osseous canal enlargement, widening of interpedicular distance o Iso- - hyperintense T1 reflecting protein/mucin content

Neurofibroma

Coronal STIR MR shows multiple bilateral thoracic and lumbar nerve root neurofibromas extending through the neural foramina into the paraspinallissues.

INTRADURAL/EXTRAMEDUllARY

lESION,

T2 HYPER, T1 ISO

~ --. OJ

a.

Epidermoid

c (Lefl) Sagittal T2WI MR shows a typical case of an intradural epidermoid tumor with well-defined margin and diffuse T2 hyperintensity (Right) Sagittal TlWI MR shows low to isoinlense signal, intradural epidermoid masses at L2-] 81 and LS-sacrum There is a dermal sinus tract extending dorsally from the low sacral regione=.

=.

--.OJ

T

m

~ --. OJ

3

a. c Q)

-<

=.

Epidermoid

CSF Disseminated Metastases (Left) Sagittal T2WI MR shows a dorsal dermal sinus ~ with intradural epidermoids involving the cauda sac lID and near conus 81. (Right) Sagittal TlWI MR shows a typical case of drop metastases from a brain gHat neoplasm: Abnormal slightly increased CSF signal intensity with poor definition of conus.

CSF Disseminated Metastases

Cysticercosis (Left) Sagittal STIR MR

shows drop metastases from a brain glial neoplasm as a vague, increased obscuration

signal and

of nerve roots of

=.

cauda equina (Right) Axial T2WI MR shows cord involvement by cysticercosis with a well-defined rounded lesion with T2

hyperintensity.

II 6 35

CAUDA EQUINA SYNDROME

__

C1l

c: Co

l/l

D_I_FF_E_R_E_N_T_IA_L_D_I_AG_N_O_S_IS __

Common • Stenosis, Acquired Spinal, Lumbar o Intervertebral Disc Herniation, Lumbar o Spondylolisthesis • Trauma o Burst Fracture, Lumbar o Sacral Fracture (Zone 3) o Traumatic Spondylolisthesis o Penetrating Injury • Post-Operative Spinal Complications • Abscess, Epidural, Paravertebral • Neoplasm o Metastases o Ependymoma, Myxopapillary, Spinal Cord o Meningioma o Arachnoid Cyst • Hematoma, Epidural-Subdural Less Common • Multiple Sclerosis, Spinal Cord Rare but Important • Sarcoidosis • Type IV AVF • Tethered Spinal Cord • Ankylosing Spondylitis ·CIDP • Guillain-Barre Syndrome (Atypical Presentation)

Stenosis, Acquired

II 6 36

Spinal, lumbar

Axial T2WI MR shows severe lumbar canal narrowing at

L4-5 =:I secondary to disc bulge, ligamentous hypertrophy, and marked facet osteophyte.

I I__

E_S_SE_N_T_IA_L_I_N_F_O_R_M_A_T_IO_N __

Key Differential Diagnosis Issues • Cauda equina syndrome (CES): Low back pain, sciatica, leg weakness, saddle hypoesthesia/anesthesia, urinary incontinence or retention, and incontinence of bowel • Substantial clinical overlap between the syndromes of the cauda equina and the conus medullaris • Most common cause is herniation of the intervertebral disc • MR or CT myelography are useful modalities to evaluate causes of CES • Acute onset CES generally considered a neurosurgical emergency, with best results if decompressed within 24-48 hours Helpful Clues for Common Diagnoses • Intervertebral Disc Herniation, Lumbar o CES occurs in approximately 1-2% of cases of herniated lumbar disc o Most patients will have a long-standing history of back problems with or without unilateral sciatica • Post-Operative Spinal Complications o Misplaced pedicle screw o Displaced surgical device (fusion cage, graft material, artificial disc) o Epidural hematoma or abscess o Incomplete decompression o Retained sponge

Intervertebral

Disc Herniation,

lumbar

=

Axial T2WI MR shows huge L5-51 extrusion completely effacing the thecal sac at this level and compressing

the cauda equina.

CAUDA EQUINA

en

SYNDROME

"0

:J

lD

~ ~

OJ ,

ij~,iI"''" ,~'", '"' "'~~~

1_,',"',,'1'

.•

=

~

=

t"

'.

~.~

,

(Left) Lateral myelography shows severe L5-S I spondylolisthesis with truncated filling of the caudal thecal sac~, (RigM) Sagittal T2WI MR shows a burst fracture of L2 with retropulsion of a large fragment inlO the canal causing severe effacement of the thecal sac and cauda

I1'0' ••

,"

1

c ~

t,

o 'I

/

a.

, "

;,

l

-~-.

I '

OJ T

m ~ ~ OJ 3

ct> a. c OJ

-<

equina compression.

"

...;1.~'~'~)

~~.~t,~ ,

Sacral Fracture

(Zone 3)

~

Abscess, Epidural, Paravertebral (Left) Axial bone CT shows highly comminuted sacral fracture with vertical fractures extending through neural foramina and a transverse fracture through S2~, (Right) Sagillal TI C+ MR shows L3-4 discilis-osleomyelilis with a large dorsal epidural abscess at Ll-] compressing the thecal sac ~,

=

=

Ependymoma,

Myxopapillary, Cord

Spinal Meningioma (Left) Sagitlal TI C+ MR shows a farge, intensely

enhancing lobulated mass filling the distal thecal sac, and expanding and

remodeling the sacrum 9:,. (Right) Sagittal TI C+ MR shows a heterogeneously

=

enhancing mass in the distal spinal canal with focal remodeling of the sacrum -7

in this patient with angiomatous meningioma of

the sacral canal.

II 6 37

SECTION 7

Intramedullary Anatomically Based Differentials Intramedullary Mass Conus Abnormality

11-7-2 11-7-6

Generic Imaging Patterns Cord, Small/Atrophic Intramedullary Lesions, Intramedullary Lesion, Intramedullary Lesion, Intramedullary Lesion, Intramedullary Lesion,

Multiple Solid Enhancement No Enhancement Diffuse/Ill-defined Enhancement Ring/Peripheral Enhancement

Modality-Specific

11-7-10 11-7-12 11-7-14 11-7-18 11-7-20 11-7-24

Imaging Findings

Intramedullary Lesion, T1 Hypointense, Intramedullary Lesion, T1 Hypointense Intramedullary Lesion, T2 Hyperintense, Intramedullary Lesion, T1 Hyperintense Cord Lesion, T2 Hyperintense, Ventral Cord Lesion, T2 Hyperintense, Dorsal Cord Lesion, T2 Hyperintense, Central

T2 Hypointense T1 Isointense

11-7-26 11-7-28 11-7-30 11-7-34 11-7-38 11-7-40 11-7-44

Anatomically Based Differentials Myelopathy

11-7-48

INTRAMEDULLARYMASS Typically located eccentrically, not involving the entire cord on axial imaging; relatively short in length « 2 vertebral bodies) o Enlargement of the cord is unusual

o

DIFFERENTIAL DIAGNOSIS Q)

c: c..

en

Common • Demyelinating Disease o Multiple Sclerosis, Spinal Cord o ADEM, Spinal Cord o Acute Transverse Myelitis, Idiopathic • Ependymoma, Spinal Cord • Astrocytoma, Spinal Cord • Syringomyelia • Contusion-Hematoma, Spinal Cord Less Common • Hemangioblastoma, Spinal Cord • Intramedullary Arteriovenous Malformation • Infarction, Spinal Cord • Cavernous Malformation, Spinal Cord • Metastases, Spinal Cord • Lymphoma

(6-14%)

•

•

Rare but Important • Sarcoidosis • Cysticercosis • Schwannoma, Intramedullary • Lipoma, Spinal • Ganglioglioma • Glioblastoma Multiforme, Spinal Cord

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • MR without and with contrast is the best tool to evaluate intramedullary processes of the cord • Discovery of an intramedullary cord lesion typically followed by imaging of the remainder of the neuraxis • Infiltrative cord lesion: Image brain to potentially identify characteristics white matter lesion(s) of multiple sclerosis • Discovery of intramedullary tumor typically accompanied by insidious onset myelopathic symptoms (months or years) • Nearly every patient with a syrinx should be imaged at least once with contrast-enhanced MR to exclude a cord neoplasm • Hemorrhagic lesion: Think ependymoma, hemangioblastoma, cavernoma, contusion Helpful Clues for Common Diagnoses • Multiple Sclerosis, Spinal Cord

II 7 2

Multiphasic lesions: Some enhance, some don't o 5-24% of patients with MS cord plaques may not have supratentorial disease at presentation ADEM, Spinal Cord o Clinical: Self-limited, monophasic demyelinating illness 5-14 days following viral infection or vaccination o Usually indistinguishable from multiple sclerosis on imaging Acute Transverse Myelitis, Idiopathic o Clinical: Acute onset myelopathy, ascending or static loss of sensory and motor function in a bilateral and symmetric distribution o Infiltrative signal abnormality may extend above level of deficit, variable enhancement o Mild fusiform enlargement may be present and simulate the appearance of primary cord neoplasm Ependymoma, Spinal Cord o Circumscribed, enhancing intramedullary mass; located centrally within the cord o Can show signs of necrosis (heterogeneity, cyst formation) and hemorrhage (hyperintense Tl, susceptibility artifact, hemosiderin "cap sign") o Most common intramedullary neoplasm in adults Astrocytoma, Spinal Cord o Fusiform enlargement, infiltrative margins, long segment of involvement; no or variable enhancement o Most commonly located in the cervical and upper thoracic cord o Uncommon/rare imaging features: Hemorrhage, necrosis, caudal location, exophytic growth, ho]ocord involvement o Cannot be reliably differentiated from ependymoma by imaging o Second most common cord neoplasm in adults, most common cord neoplasm in children (60%) o

•

•

INTRAMEDULLARY MASS • Syringomyelia o Abnormal cystic cord lesion with surrounding gliosis; variable expansion of the cord; focal or extensive; typically longitudinal o Secondary to chronic insult/injury (cavitation) or to altered CSF dynamics in the central canal of the cord (technically termed hydromyelia, such as seen in Chiari I malformation) Helpful Clues for Less Common Diagnoses • Hemangioblastoma, Spinal Cord o Intensely enhancing, hypervascular tumor(s); usually located dorsally within the cord o Multiple lesions common (check the posterior fossa!) o Mayor may not have an associated syrinx, which can be disproportionately large relative to the size of the actual enhancing tumor o Often with signs of prior hemorrhage o Often with prominent serpiginous subarachnoid flow voids due to enlarged draining veins o 70-90% NOT associated wi th von Hippel-Lindau • Intramedullary Arteriovenous Malformation o Hyperintense T2 signal in the cord o Tortuous vesselslflow voids on MR, hypervascularity on CT angiography • Infarction, Spinal Cord

Demyelinating

Sagitlal T1 enhancement in

c+

this patient

prodrome.

\vith

an acute

Helpful Clues for Rare Diagnoses • Sarcoidosis o May simulate other diseases; diagnosis usually preceded by known pulmonary systemic involvement

or

Other Essential Information • Tumor associated syrinx (a.k.a., polar or satellite cysts): Intramedullary fluid collections rostral &/or caudal to the tumor, with nonenhancing margins • More rostral tumor associated with higher likelihood of syrinx formation

Disease

MR shows 3 foci of pathologic

=.::I due to ADEM

Hyperintensity on T2WI, possibly with mild expansion o Conus and variable thoracic cord involvement, cervical ischemia is atypical o Most often associated with aortic pathology (dissection, thoracoabdominal aortic surgery), rarely with atherosclerotic disease or embolism • Cavernous Malformation, Spinal Cord o Variable hyperintensity on TI, heterogeneously hyperintense on T2 with surrounding rim of susceptibility due to prior episodes of hemorrhage that blooms on gradient echo sequences o Rare enhancement; may have some surrounding edema if recent bleed • Metastases, Spinal Cord o Most common primary is lung, followed by breast o

within the cervical cord ilJness {oJ/owing

viral

=-

Sagittal T2WI MR shows complex cervical cord mass containing foci of susceptibiHty demonstrating prior hemorrhage within an ependymoma.

II 7 3

2:rn

INTRAMEDULLARY

MASS

:J

TI Q)

E rn ~

C Q)

c: Co (/)

Astrocytoma,

Spinal Cord

(Left) Sagittal T7 C+ MR shows enhancing intra-axial mass with rostral and cauda! syrinx and satellite lesion r=:l enlarging the cervical cord. Note severe syringobulbia (Right) Sagittal T2WI MR shows infiltrative

lesion expanding

the mid-cervical

cord. C3- S

decompressive laminectomy has been pedormed.

Contusion-Hematoma,

Spinal Cord

(Left) Sagittal T2WI MR shows haustrated CSF-signal mass in the central cord in a patient with a Chiar; 7

=

malformation.

Hypointense

foci r=:l are due to flow artifact. (Rig"') Sagittal STIR MR shows heterogeneously hyperintense conus lesion representing a hemorrhagic cord contusion, secondary to L7 burst

=

fracture

and traumatic

spondylolisthesis l:1.

Hemangioblastoma, (Left) Sagittal T7 C+ MR shows a Focal enhancing hemangioblastoma mass expanding the cervical cord at C4 with associated syrinx. There is a large cerebellar cystic mass as \Veil 156 (Righi) Sagittal T2WI MR shows patchy hyperintensity \Vithin the cord '5'] due to intramedullary arteriovenous malformation.

Note dorsal

flow voids due to tortuous,

dilatated vascularity~

II 7 4

Spinal Cord

Intramedullary Arteriovenous Malformation

INTRAMEDUllARY

Infarction, Spinal Cord

MASS

Cavernous Malformation, Spinal Cord (Left) Sagittal T2WI FSEMR shows infiltrative hyperintensity and mild enlargement of the conus medul/aris B in this patient with lower extremity paralysis following aortic aneurysm repair. (Right) Sagittal T2WI MR shows slightly expansile intramedullary lesion at the C2-] level [i'8 with classic mixed hyperintense ("popcorn") lesion surrounded by a hypointense rim.

Metastases, Spinal Cord

Sarcoidosis (Left) Sagittal T 1 C+ FS MR show focal intramedullary breast carcinoma metastasis enlarging the distal cord =:I.

Note vertebral metastasis B with mild compression

(racture. (Right) Sagittal T1 C+ MR demonstrates extensive cord enlargement and intramedullary

enhancement due to sarcoidosis.

Schwan noma, Intramedullary (Left) Axial T1 C+ MR shows small, circumscribed intramedullary enhancing focus representing an intramedullary schwannoma in this patient with neurofibromatosis type 2. (Rigl1t) Sagittal T2WI MR shows infiltrating brainstem

=-

and cervical cord mass with exophytic growth into the 4th ventricle.

II 7 5

CONUS ABNORMALITY

DIFFERENTIAL DIAGNOSIS Ql

c: a.

lI)

Common • Filum Terminale Fibrolipoma • Primary Cord Neoplasm o Ependymoma, Myxopapillary, Spinal Cord o Astrocytoma, Spinal Cord o Hemangioblastoma, Spinal Cord o Paraganglioma • Demyelinating Disease • Syringomyelia • Tethered Spinal Cord Less Common • Cavernous Malformation, • Infarction, Spinal Cord • Ventriculus Terminalis

Spinal Cord

Rare but Important • Metastases, Spinal Cord • Arteriovenous Malformation/Fistula • Developmental Abnormality o Terminal Lipoma o Diastematomyelia o Dorsal Dysra phism • Myelomeningocele/Myelocele • Lipomyelomeningocele/Lipomyelocele • Terminal Myelocystocele o Caudal Regression Syndrome o Segmental Spinal Dysgenesis • Infection o Schistosomiasis o Cysticercosis o Tuberculoma

ESSENTIAL INFORMATION

II 7 6

• Marked enhancement typical • Can show signs of necrosis (heterogeneity, cyst formation) and hemorrhage: Subarachnoid hemorrhage, superficial siderosis • Bony remodeling when large: Vertebral scalloping, foraminal enlargement, widened and eroded pedicles o Astrocytoma, Spinal Cord • Cervical/upper thoracic most common; rarely involves conus o Hemangioblastoma, Spinal Cord • Focal hyperenhancing lesion(s), often with disproportionately large syrinx • Multiple sites of involvement in cord and posterior fossa typical • Often with signs of prior hemorrhage • 70-90% NOT associated with von Hippel-Lindau o Paraganglioma • Virtually indistinguishable from the much more common myxopapillary ependymoma o Infection (e.g., schistosomiasis) can simulate a conus neoplasm • Demyelinating Disease o Isolated involvement of the conus with multiple sclerosis probably extremely rare o Case reports of isolated conus involvement with other causes of demyelination (e.g., ADEM) • Syringomyelia o Hydrosyringomyelia of the conus can occur as an isolated finding or as a component of more extensive involvement o Terminal syringomyelia can be seen with tethered cord • Tethered Spinal Cord o Tip of conus usually lies at the T12-L2 level o Tip of conus below L2-3 is abnormal o Associated abnormalities include thick filum, dysraphism, vertebral anomalies, etc. Helpful Clues for Less Common Diagnoses • Cavernous Malformation, Spinal Cord o Variable hyperintensity on Tl, heterogeneously hyperintense on T2 with surrounding rim of susceptibility due to prior episodes of hemorrhage, which blooms on gradient echo sequences

CONUS ABNORMALITY

Rare enhancement; may have some surrounding edema if recent bleed • Infarction, Spinal Cord o Hyperintensity on T2WI, possibly with mild expansion o Most often associated with aortic pathology (dissection, thoracoabdominal aortic surgery), rarely with atherosclerotic disease or embolism • Ventricularis Terminalis o Incidental, transient finding of childhood mild dilatation of the caudal terminus of the central canal in an otherwise normal conus o Up to 2-4 mm diameter and :s 2 cm length o No signal changes or enhancement in adjacent parenchyma o

Helpful Clues for Rare Diagnoses • Metastases, Spinal Cord o Hematogenous spread: Most common primary is lung, followed by breast o Drop mets: Medulloblastoma, ependymoma, GBM • Arteriovenous Malformation/Fistula o Hyperintense T2 signal in the cord o Tortuous vessels/flow voids on MR, hypervascularity on CT angiography • Terminal Lipoma o Fatty mass associated with conus medullaris (e.g., not a neural placode) o Usually with a tethered cord; posterior bony dysraphism may be present • Dorsal Dysraphism

Common features: Everted elements of neural arch; tethered, dysraphic cord o Lipomyelomeningocele and 1ipomyelocele: Neural placode adherent to fatty mass which is contiguous with subcutaneous fat; intact overlying skin o Myelomeningocele and myelocele: Neural placode exposed (no overlying skin) o Lipomyelocele and myelocele: eural placode lies within spinal canal o Lipomyelomeningocele and myelomeningocele: eural placode and CSF-filled meningeal sac protrude through the dorsal spinal defect o Terminal myelocystocele (least common): CSF-filled meningeal sac, containing a tethered cord with a terminal hydromyelic cyst, extend through a caudal sacral defect; intact overlying skin • Schistosomiasis o Intense inflammatory reaction with ischemic necrosis due to infection by parasitic trematodes o Cord edema and ill-defined enhancement over several segments; cord enlargement o May simulate tumor o Thoracic cord and conus involvement common • Cysticercosis o Spinal intramedullary cysticercosis is rare; more common with intradural cysts o Intramedullary disease presents with peripherally enhancing cystic lesions, edema o

Ependymoma, Filum Terminale

Fibrolipoma

Sagiual T1WI MR shows linear hyperintensity within the cauda equina, with normal positioning of the conus~.

Myxopapillary, Cord

~ ~ III 3 CD a. c

III

-<

Spinal

Sagittal T2WI MR shows enlargement of conus medullaris by hyperintense mass ~. Multiple schwannomas seen in cauda equina in this patient with neurofibromatosis type 2.

II 7 7

CONUS

ABNORMALITY

Hemangioblastoma, Q)

c: c.

lI)

Spinal Cord

(Lefl) Sagiltal T2WI MR shows enlargement of the conus medullaris by an expansile intramedullary

mass

=. Decompression

laminectomy has been performed. (RighI) Sagiual T1 C+ MR shows large, solid, avidly enhancing mass involving the conus with tumor syrinx superiorly ~.

=

Demyelinating

Disease

Syringomyelia

(Lefl) Sagiual T2WI MR shows patchy hyperintensity and expansion of the conus medullaris in this child with ADEM. (RighI) Sagiltal T2WI MR shows haustrated syringomyelia of the distal thoracic cord and conus in this child with a Chiari malformaOon.

=

Tethered Spinal Cord (Lefl) Sagiltal T1 WI MR shows a low·lying conus, terminating at the L]-4 level A thickened filum

=.

terminale

was identified

on

axial imaging. (RighI) Sagiual T2WI MR shows hyperinlensity in the dorsal conus with faint fusiform enlargement in this patient with acute lower extremity paralysis following

=

aortic aneurysm

II 7 8

repair.

Infarction, Spinal Cord

CONUS

Ventriculus

Terminalis

ABNORMALITY

Metastases, Spinal Cord (Left) Sagittal T2WI MR shows the typical appearance of ventriculus lerminalis,

with fusiform

enlargement of the caudal end of the central canal =::I. (Right) Sagittal T2WI MR shows a rounded metastatic lesion within the conus medullaris =::I and rather extensive edema throughout the visualized cord PJ:ll.

Arteriovenous

Malformation/Fistula

Terminal

Lipoma (Left) Sagittal T2WI MR shows hemorrhagic lesion of the conus 81 (note hemorrhagic fluid-fluid leve/) with multiple pial flow voids PJ:ll in this patient with a type 2 AVM. (Right) Sagittal T1 WI MR shows a 100v-lying, tethered cord terminating in a small lipoma 6B

(Left) Sagittal T1WI MR shows low-lying cord with nellral placode adherent 10 a caudal Fatty mass, which is contiguous with the subcutaneous fat through a large dorsal lumbosacral bony defect. The disjunction lies within the canal (Right) Sagittal T2WI MR shows shortened cord with abruplly truncated conus medullaris 81. Note mild hydromyelia and disordered lower vertebral column with diminutive, dysplastic

sacrum=.

II 7 9

CORD, SMALl/ATROPHIC

DIFFERENTIAL DIAGNOSIS Ql

c: Co (/)

Common • Focal Cord Atrophy o Compressive Myelopathy, Chronic o Multiple Sclerosis, Other Noncompressive Myelopathies o Cord Trauma, Chronic o Infarction, Spinal Cord, Chronic o Radiation Myelitis, Chronic • Diffuse Cord Atrophy o Multiple Sclerosis (or Other Noncompressive Myelopathy) o Chronic, Severe Cord Trauma (e.g., Transection) o Severe Cerebral Atrophy o Infarction, Spinal Cord, Chronic o Collapsed Syrinx Rare but Important • Spinal Cord Herniation • Spinocerebellar Ataxia (Friedreich Ataxia), Other Hereditary Paraplegia/Ataxia Syndromes • Segmental Spinal Dysgenesis

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Compressive Myelopathy, Chronic o Chronic cord injury due to mechanical impingement by disc herniation, spondylolisthesis, or spinal canal mass o Offending lesion may have been surgically decompressed

• Multiple Sclerosis, Other Noncompressive Myelopathies o Diverse group of etiologies: Non-MS diagnoses include ADEM, SL£, sarcoidosis, HIV, syphilis, Lyme disease, and paraneoplastic syndromes • Cord Trauma, Chronic o Patient history usually reveals diagnosis o Atrophy may be focal; in severe and proximal cases, holocord involvement may be present • Infarction, Spinal Cord, Chronic o Uncommon due to vascular supply of cord Alternative Differential Approaches • Cervical cord typically occupies 75% of spinal canal diameter; less than 50% generally accepted as cord atrophy • Maximal cervical cord dimensions o MR and CT myelography: 7.2 mm AP x 13.8 mm transverse (C4-5) (Fountas) o Autopsy: 0.9 mm AP x 14.9 mm transverse (C4-5) (Nordqvist)

SELECTED REFERENCES l. 2.

Fountas KN et al: Cervical spinal cord--smaller than considered? Spine. 23(14): 15 13-6, 1998 Nordqvist L: Sagittal diameter of the spinal cord and subarachnoid space in different age groups: a roentgenographic post-mortem study. Acta Radiol Diagn. 5(Suppl):1-96,1964

Multiple Sclerosis, Other Noncompressive Myelopathies

II 7 10

Sagittal T7WI MR shows diffuse cord atrophy from chronic mechanical compression by marked thoracic OPLL=.

Sagittal STIR MR shows diffuse cord atrophy and patchy hyperintensity in this patient with chronic multiple sclerosis.

CORD, SMALl/ATROPHIC ~ ~ Ql (LeFt) Sagillal T2WI MR shows diFFusecord atrophy From HIV myelopathy. (Right) Sagittal T2WI MR in this patient status post resection of a thoracic ependymoma shows tethering of an atrophic cord dorsally into the mid-thoracic laminectomy deFect.

Cord Trauma, Chronic

3 CD c. C Ql

-<

Infarction, Spinal Cord, Chronic (Left) Sagittal T2WI MR in this childhood MVA patient shows cord atrophy, most Focally at the TJ-4 level 81. NOle decompression laminectomy. Distally, small syrinx is present =:I. (Right) Sagittal T2WI MR shows diFFusecord atrophy in this patient with remole post-traumatic aortic dissection.

Spinal Cord Herniation (LeFt) Sagittal T2WI MR shows atrophic cervical cord containing collapsed syrinx =:I. Note suboccipital craniectomy and C 1 laminectomy

for

decompression of Chiari malFormation 81. (Right) Sagillal T2WI MR shows anterior tethering of the cord with enlargement of the dorsal CSF space and Focal AP narrowing of the cord

=:I

II 7 11

INTRAMEDULLARY LESIONS, MULTIPLE

DIFFERENTIAL DIAGNOSIS Q)

c: c.

Ul

Common • Multiple Sclerosis, Spinal Cord • Metastases, Spinal Cord • ADEM, Spinal Cord Less Common • Hemangioblastoma, Spinal Cord • Ependymoma, Cellular, Spinal Cord • Cavernous Malformation, Spinal Cord Rare but Important • Sarcoidosis • Cysticercosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Lesions in other locations such as osseous, supratentorial, & systemic can help with differential considerations Helpful Clues for Common Diagnoses • Multiple Sclerosis, Spinal Cord o 2/3 of cord lesions in cervical cord & < 2 vertebral segments in length o Dorsolateral aspect of cord involving gray & white matter o Enhancement lasts 1-2 months • Metastases, Spinal Cord o Typically < 1.5 em with extensive edema o Brain mets in 20% • ADEM, Spinal Cord o Multifocal flame-shaped white matter lesions

Multiple Sclerosis, Spinal Cord

II 7 12

Sagittal T2WI MR demonstrates mulUple hyperintense

intramedullary lesions·~

with focal cord enlargement,

typical of demyelinaUon. Spinal cord & brain gray matter involvement is common in MS.

• Variable enhancement, depending on the stage o Little mass effect or edema o Supratentorial involvement is typical Helpful Clues for Less Common Diagnoses • Hemangioblastoma, Spinal Cord o 75% sporadic; 25% VHL-associated • Ependymoma, Cellular, Spinal Cord o Many grow centrifugally & usually cause symmetric expansion of cord • May help to differentiate from astrocytomas: More infiltrating, causing asymmetric, lumpy cord expansion • Cavernous Malformation, Spinal Cord o Multiple lesions in approximately 15-33% of spontaneous cases • Familial form is autosomal dominant with variable expression & more commonly has multiple lesions, occurring in as many as 73% Helpful Clues for Rare Diagnoses • Sarcoidosis o Invariable presence of systemic disease o Intramedullary lesions in cervical & thoracic cord • Cysticercosis o 5% of neurocysticercosis cases, involving subarachnoid space most commonly • Thoracic cord predilection related to higher percentage blood flow

Metastases,

Spinal Cord

Sagillal TI c+ MR shows mulliple enhancing nodules within the cord from metastatic leukemia There is

=.1.

diffuse expansion

of the cord.

INTRAMEDULLARY

ADEM, Spinal Cord

LESIONS,

MULTIPLE

Hemangioblastoma,

Spinal Cord (Left) SagiLLalT2WI MR demonstrates numerous hyperintense inlramedullary lesions within the medulla 81 & cervical spinal cord characteristic of demyelinating lesions. Lesions typically involve both gray & white matter structures. (RighI) SagiLLal TlWI MR shows 2 enhancing intramedullary foci 1:'.2 in Ihe distal cord and conus with associated intraspinal cyst 81. Multiple small tumors are seen in von rlippel-Lindau syndrome.

=-

Cavernous Malformation, Spinal Cord (Lefl) SagiLLalTl C+ MR shows 2 intramedullary enhancing lesions in the cervical cord 81. There is fusiform cord enlargement & a rostral cyst 1:'.2. (RighI) Sagittal T2WI MR shows a lobulated mass in the distal cord. The heterogeneous signal reflects various ages of blood by-products 81. No edema or cord expansion is seen. 10-30% are multiple & more often seen with {amilial cavernous

malformation

syndrome.

Sarcoidosis (Left) SagiLLalTl C+ MR shows peripheral intramedullary 1:'.2 & leptomeningeal nodular enhancing foci~. Central intramedullary spread is via perivascular spaces. (RighI) Sagittal T2WI MR shows 2 focal intramedullary areas of slightly decreased signal within an extensive area of

cord edema 1:'.2. T2 hypointensity may ref/ect calcification in degenerated cyst wall.

II 7 13

INTRAMEDUllARY

LESION, SOLID ENHANCEMENT

DIFFERENTIAL DIAGNOSIS Ql

c: '0. C/)

Common • Ependymoma, Cellular, Spinal Cord • Ependymoma, Myxopapillary, Spinal Cord • Astrocytoma, Spinal Cord • Multiple Sclerosis, Spinal Cord Less Common • Hemangioblastoma, Spinal Cord • ADEM, Spinal Cord • Cavernous Malformation, Spinal Cord • Neuromyelitis Optica • Type I DAVF Rare but Important • Lymphoma • Metastases, Spinal Cord • Infarction, Spinal Cord • Type II AVM • Ganglioglioma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Look for multiple lesions, supratentorial lesions, & osseous lesions in metastases, multiple sclerosis, ADEM, & hemangioblastoma • Internal hemorrhagic products with heterogeneous T1/T2 signal can be seen with certain lesions, such as cavernous malformation, ependymoma, & paraganglioma

II 7 14

Helpful Clues for Common Diagnoses • Ependymoma, Cellular, Spinal Cord o Well-circumscribed, intensely enhancing intramedullary mass causes fusiform cord enlargement • Hemosiderin at cranial or caudal margin "cap sign" in 20-64% of cases • Polar or intra tumoral cysts in 50-90% o Associated syrinx & surrounding edema • Ependymoma, Myxopapillary, Spinal Cord o Intensely enhancing glioma arising from ependymal cells of filum terminale, conus, cauda equina • May be T1 hyperintense due to mucin accumulation • T2 hyperintense lesion; hypointense at margin due to hemosiderin

May have bony canal expansion Usually spans 2-3 vertebral segments • Astrocytoma, Spinal Cord o Intramedullary enhancing, infiltrating mass that expands the cord • Cervical> thoracic • Usually < 4 segments • Multisegmental or holocord, more common with pilocystic astrocytoma o May be associated with cyst/syrinx • Multiple Sclerosis, Spinal Cord o 10-20% cases have isolated spinal cord involvement o Cervical cord is most commonly affected o Dorsolateral aspect of cord o Enhancement during the acute or subacute state can be homogeneous, nodular, or ring enhancing o o

Helpful Clues for Less Common Diagnoses • Hemangioblastoma, Spinal Cord o Subpial intramedullary mass on dorsal aspect of cord shows intense, homogeneous enhancement • ± Syrinx in > 50% • Lesions "- 2.5 cm show serpentine flow voids o Extensive, long segment edema o Hemorrhage is common • ADEM, Spinal Cord o Multifocal spinal cord white matter lesions with little mass effect or vasogenic edema o Brain typically also involved o Enhancement depends on stage • ± erve enhancement • Cavernous Malformation, Spinal Cord o Mottled/speckled pattern due to varying stages of blood products: "Popcorn" appearance o Hemosiderin ring o ± Minimal enhancement o No edema unless recent hemorrhage • Neuromyelitis Optica o Idiopathic demyelinating syndrome involving the optic nerves and spinal cord o Lesions extending over 3 or more vertebral segments on spinal cord MR o Distinct from "typical" MS is > 50 cells/mm3 in CSF (often polymorphonuclear) & absent oligoclonal bands o Normal initial brain MR

INTRAMEDUllARY

LESION, SOLID ENHANCEMENT

NMO-IgG seropositivity Associated with several systemic diseases including collagen vascular diseases, autoantibody syndromes, infections, & toxin exposures • Type I DAVF o Cord central T2 hyperintensity + prominent intradural vessels on cord surface o May show diffuse (usually faint) cord enhancement o Distal thoracic cord/conus most common location o o

Helpful Clues for Rare Diagnoses

• Lymphoma o Poorly-defined mass • Involving cervical> thoracic> lumbar o Enhancement varies from patchy to confluent & infiltrating to discrete o Non-Hodgkin lymphoma (predominantly B-cel1)> Hodgkin disease • Metastases, Spinal Cord o Focal enhancing cord lesion with extensive edema, out of proportion to small lesion o Typically < 1.5 cm & well-circumscribed o Conus least commonly involved o Hemorrhagic metastases can be seen from thyroid and melanoma • Infarction, Spinal Cord o Focal T2 hyperintensity & slight cord expansion o Patchy, ill-defined intramedullary enhancement in subacute phase

Sagittal T1 C+ MR shows fusiform expansion of the

Due to spinal occlusion: Radicular branch of vertebral artery in cervical cord or aorta in thoracic & lumbar cord o Thoracic cord most frequently involved as it is an arterial border zone • Type II AVM o Intramedullary glomus type arteriovenous malformation • Nidus may extend to the dorsal pial surface o Variable enhancement of nidus, cord, vessels o Large cord with heterogeneous Tl/T2 signal due to blood products o Prominent flow voids, likely draining coronal venous plexus • Ganglioglioma o Young patients (4-38 years, mean = 12 years) • Cervical> thoracic> filum o Long tumor length without edema o Tumoral cyst o Bone erosion and scoliosis o Mixed signal intensity on T1WI & patchy enhancement with cord surface enhancement o

SELECTED REFERENCES 1. 2.

Wingerchuk DM et al: The clinical course of neuromyelitis optica (Devic's syndrome). Neurology. S3(S):1107-14, 1999 Patel U el al: MR of spinal cord ganglioglioma. AJ RAm J Neuroradiol. 19(5):879-87, ] 998

cervicothoracic cord with a large solidly enhancing mass from T1-2 junction to T4 level ~ There is a small

Sagittal T1 C+ MR shows diffuse central cord expansion with solid enhancing nodule 1:':1 and cephalad cyst. Enhancement degree and pattern is variable in cord

intra-tumoral cyst at the rostral margin

ependymomas.

=.

II 7 15

INTRAMEDUllARY

Astrocytoma, Ql

c: Q.

en

(Left) Sagittal shows a large mass involving thoracic cord, segment

LESION, SOLID ENHANCEMENT

Spinal Cord

Multiple Sclerosis, Spinal Cord

T1 C+ MR enhancing the upper with long

fusiform cord

expansion. The enhancement

is fairly

homogeneous with an irregular inferior margin C=. (Right) Axial T1 C+ MR shows a peripheral, well-defined focus of cord enhancement 81. The multiplicity of lesions along with lack of edema or significant cord expansion is typical for demyelinating disease.

Hemangioblastoma,

Spinal Cord

ADEM, Spinal Cord

(Left) Sagittal T1 C+ MR of the hemangioblastoma ~ but no enhancement of the tumor-associated cysts E:I inferior & superior to the tumor. Edema typically spares the cord periphery. (Right) Sagittal T I C+ MR shows abnormal eccentric, homogeneous lesion enhancement Lesion enhancement may be either homogeneous or ring configuration. shows focal enhancement

=.

Cavernous Malformation, (Left) Sagittal T1 C+ MR shows mild enhancement of a mostly isoinlense, slightly expansile intramedullary lesion at the C2-3 level =:lI. (Right) Sagittal T1 C+ MR shows fusiform expansion & extensive enhancement of the cord with longitudinally extensive T2 signal abnormality> 3 vertebral segments (not shown). Note the small upper thoracic cord due to prior demyelination wilh atrophy 1!:llI.

a

II 7 16

Spinal Cord

Neuromyelitis

Optica

INTRAMEDULLARY

LESION, SOLID ENHANCEMENT

~ Ol 3 a.
(Left) Axial T1 C+ MR shows extensive diffuse enhanCemenllhroughoul the cord substance ~ in relapsing neuromyelitis optica. (Right) Sagittal T1 C+ FS MR show extensive confluent enhancement of the distal thoracic cord. Typical findings of cord T2 hyperintensity and intradural vessels were also present.

Metastases, Spinal Cord

c OJ

-<

Infarction, Spinal Cord (Left) Sagittal T1 C+ FS MR shows scattered bony metastatic lesions & slight expansion of the conus E:I with a focal intramedullary enhancing lesion. (Right) Axial T1 C+ MR shows intramedullary central cord enhancement in the subacute phase.

=

=

Ganglioglioma (Lefl) Sagittal T1 C+ FS MR

shows pronounced intramedullary spiculated enhancement B1 due to a compact intramedullary nidus. Multiple flow voids P..:tJ are seen within cord, along dorsal cervical cord surface,

and within

subarachnoid space. (Right) Sagittal T1 C+ MR shows infiltrating

brainstem

and

cervical cord mass ~ with irregular enhancement. Tumor extends exophytically into the 4th ventricle

II 7 17

INTRAMEDULLARY LESION, NO ENHANCEMENT

DIFFERENTIAL DIAGNOSIS Ql

c: c.

rJ)

Common • Syringomyelia • Multiple Sclerosis, Spinal Cord • Contusion-Hematoma, Spinal Cord • Acute Transverse Myelitis, Idiopathic Less Common • Astrocytoma, Spinal Cord • Ependymoma, Cellular, Spinal Cord • Infarction, Spinal Cord • ADEM, Spinal Cord • Cavernous Malformation, Spinal Cord Rare but Important • Neurenteric Cyst

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Imaging of ADEM may be similar to fulminant multiple sclerosis; however, the former is monophasic Helpful Clues for Common Diagnoses • Syringomyelia o Cystic intramedullary lesions that may be loculated with septations o Enhancement suggests inflammatory or neoplastic lesion • Multiple Sclerosis, Spinal Cord o Enhancement during acute/subacute phase & lasts 1-2 months • Does not reflect disease progression

Cord atrophy usually in late stage & correlates with clinical disability • Contusion-Hematoma, Spinal Cord o Acute: Iso-/hypointense with cord swelling o Chronic: Focal/segmental atrophy • Acute Transverse Myelitis, Idiopathic o Centrally located lesion, 3-4 segments in length o Variable enhancement depending on age o

Helpful Clues for Less Common Diagnoses • Astrocytoma, Spinal Cord o 10% of cord tumors may show no enhancement o Typically low grade astrocytomas (WHO grade I, II) o Fusiform cord expansion, T2 hyperintensity o Cysts uncommon in nonenhancing tumor subclass • Infarction, Spinal Cord o Early stage may have no Tl signal abnormality o ± Patchy enhancement in subacute phase • Cavernous Malformation, Spinal Cord o Absent or minimal enhancement Helpful Clues for Rare Diagnoses • Neurenteric Cyst o Fluid intensity cystic lesion, typically in tra dural/ extramedullary o Segmentation & fusion anomalies

Multiple Sclerosis, Spinal Cord

II 7 18

rs

=.

Sagittal T1 WI MR shows an elongated, cystic int,amedullary lesion SI with CSF signal. This cavity is loculated with septaUons Note the cerebellar

Sagiltal T2WI MR shows rocal hyperintensity within cord at C3 and C5 levels Ilomogeneous, nodular,

lonsillar ectopia

subacute phase & lasts 1-2 months.

=.

=.

or ring enhancement occurs during the acute or

INTRAMEDULLARY

Contusion-Hematoma,

Spinal Cord

lESION,

NO ENHANCEMENT

Acute Transverse Myelitis,

Idiopathic (Left) Sagillal T2WI MR shows mild cord expansion and hyperintensity at C3-C4 the level of ALL & PLL injury and posterior subluxation There is extensive preverlebral edema eJ. (Right) Sagillal T7WI MR shows a cervical intramedullary lesion spanning 5 vertebral segments from C2-3 to C7 It is relatively T7 hypointense and T2 hyperintense (not shown).

=

=.

=.

Astrocytoma,

Spinal Cord

Infarction,

Spinal Cord (LeFt) Sagillal T7 C+ MR shows a very large nonenhancing

spinal cord

=

astrocytoma encompassing the entire cervical cord. (Right) Sagillal T2WI MR shows mild cord expansion & ventral cord hyperintensity

=.

ADEM,

Spinal Cord

Cavernous Malformation,

Spinal Cord (LeFt) Sagillal T2WI MR shows multiple foci of hyperintensity scallered throughout the cervical cord with focal cord expansion This is similar imaging to fulminant multiple sclerosis, but ADEM is typically monophasic. (Right) Sagillal T2WI MR shows well-circumscribed region of heterogeneous signal eJ within the cord due to varying ages of blood products. Surrounding hypointensity!:OJ is likely due to a hemosiderin

=.

Slaining.

II 7 19

INTRAMEDULLARY

LESION,

DIFFUSE/ILL-DEFINED

DIFFERENTIAL DIAGNOSIS Ql

r:: 0W

Common • Multiple Sclerosis • Transverse Myelitis (ATM) • ADEM • Viral Myelitis • Neuromyelitis Optica (NMO) Less Common • Type I Spinal Dural A-V Fistula • Dural A-V Fistula (Brain) • Arterial Infarction • Spinal Cord Metastases • Astrocytoma Rare but Important • Radiation Myelopathy • Abscess/Myeli tis • Parasitic or Bacterial Infections

ESSENTIAL INFORMATION

II 7 20

Helpful Clues for Common Diagnoses • Multiple Sclerosis o Patchy or confluent enhancement o Cervical> thoracic o Small focal areas of T2 signal abnormality o Dorsal cord at C1-2 common location • Transverse Myelitis (ATM) o Can be secondary to known cause (e.g., MS, ADEM, cord ischemia) o Can be idiopathic (unknown cause) 15% o Thoracic> cervical o Imaging normal in up to 50% • ADEM o Immune-mediated, inflammatory white matter disorder • Para/post-infectious • Post-immunization o Typically monophasic illness o Any age (more common in child, young adult) o Brain affected more than spinal cord o Can be multifocal, patchy, or confluent o Check brain for multi focal white matter lesions with relatively little mass effect • Viral Myelitis o Acute/subacute viral infection (e.g., HIV, enteroviruses, H HSV6) o Usually multisegmental o Variable enhancement from subtle to profound

•

ENHANCEMENT

euromyelitis Optica (NMO) o Autoimmune, inflammatory disorder involving myelin of optic nerves and spinal cord o Longitudinally extensive (> 3 vertebral segments) T2 hyperintensity within cord o Presence of brain WM lesions does not exclude NMO o May reflect autoimmune targeting of Aquaporin-4 transmembrane channel proteins o Respiratory failure due to extensive cervical involvement in up to 1/3 cases (very uncommon in MS) o Radicular pain in 35% (uncommon in MS) o Lhermitte symptom common in MS and NMO

Helpful Clues for Less Common Diagnoses • Type I Spinal Dural A-V Fistula o Causes venous hypertension o Intradural flow voids on cord surface from arterialized veins o Swollen, edematous cord o Multisegmental T2 signal abnormality o Variable enhancement • Arterial Infarction o Sudden onset weakness, loss of sensation o Rapidly progressive o Causes • Anterior spinal or radicular artery occlusion • Hypotension o Thoracic (conus) > cervical o Nonspecific T2 hyper intensity ± ill-defined cord enhancement • Spinal Cord Metastases o Focal, enhancing cord lesion(s) with extensive edema o Lung, breast most common primary o Rapidly progressive flaccid paraparesis o Full craniospinal imaging when focal cord lesion found o Edema out of proportion to focal small cord lesion suggests metastasis, even if solitary • Astrocytoma o Enhancing infiltrating mass expanding cord o Cervical> thoracic o Usually < 4 segments o Occasionally asymmetric, even exophytic

INTRAMEDULLARY

LESION,

DIFFUSE/Ill-DEFINED

o Differential considerations

o 80-90% low grade o Slow onset of myelopathy Helpful Clues for Rare Diagnoses • Radiation Myelopathy o Spindle-shaped cord swelling with irregular, focal rind of enhancement o Typically with doses over SO Grey (Gy) o Demyelination in lateral, dorsal tracts o Concurrent chemotherapy may be a predisposing factor, especially if intrathecal • Parasitic or Bacterial Infections o Typical is well-defined, ring-enhancing mass within cord, with appropriate clinical history of inflammation/infection o More uncommon ill-defined or patchy enhancement o Schistosomiasis => ill-defined punctate enhancement of conus Other Essential Information • Long (multisegmental) cord enlargement with edema, patchy enhancement favors infection/inflammation over neoplasm • Do sagittal FLAIR or T2WI of brain in patients with unexplained myelopathy, cord lesions! oMS, ADEM usually have coexisting brain lesions

ENHANCEMENT

o =>

o

include

MS

Systemic disease • Sjogren, SLE o => Vascular o => Parainfectious (ADEM) o => Radiation myelopathy o => Idiopa thic • Acute transverse myelitis (ATM) o Subset of transverse myelopathy o Excludes compressive lesions o Requires evidence of cord inflammation • CSF pleocytosis or elevated IgG or MR contrast-enhancement o Bilateral signs and symptoms, Clear sensory level o Progression of clinical symptoms to nadir between 4 hours and 21 days o Exclusion criteria for ATM • Sarcoid • Behc;et, Sjogren, SLE • Infectious etiologies (Lyme, HIV, Mycoplasma, viral) =>

SELECTED

REFERENCES

1.

Matiello M et al: Neuromyelitis

2.

20(3):255-60, 2007 Wingerch~lk D~ et al: Comparative immunopathogenesis of a.cute dlssemmated encephalomyelitis, neuromyelitis

optica. Curr Opin Neural.

optlca, and multiple sclerosis. Curr Opin Neurol.

Alternative Differential Approaches • Acute transverse myelopathy o Includes both inflammatory and noninflammatory etiologies o Excludes compressive lesions

Sagillal T7 c+ MR shows mulliple foci of cord enhancement in multiple sclerosis, some well-defined ~ and others ill-defined 81.

20(3):343-50, 2007

=

Sagittal TI C+ FS MR shows patchy cervical cord enhancement in this patient with acule idiopathic lIansverse myelopathy No definite etiology was established.

II 7 21

~

INTRAMEDULLARY

Cll

LESION, DIFFUSE/ILL-DEFINED

ENHANCEMENT

:J

-0 Q)

E Cll ~

C Q)

c: a.

CIl

ADEM (Left) Sagittal T7 C+ MR shows diffuse, patchy enhancement ~ of the uppe, and middle thoracic spinal cord in this patient with myelopathy following flu-like illness. (Right) Sagittal T7 C+ MR shows a diffusely enlarged, swollen upper cervical cord with ill-defined enhancement in this patient with ADEM. Myelopathy began 2 weeks after flu-like illness.

=

Viral Myelitis (Left) Sagittal T7 C+ MR in a patient with herpes myelitis

=

shows extensive cord edema and patchy enhancement from C4 to the C7-T7 level. (Right) Sagittal T7 C+ MR shows minimal patchy enhancement

of the cord in

NMO, with diffuse cord expansion. Cord

demonstrated extensive T2 (not shown) as did the optic nerves. abnormality

Type I Spinal Dural A-V Fistula (Left) Sagittal T7 C+ FS MR shows patchy and ill-defined enhancement of the distal spinal cord 8l with

scatlered prominent vessel enhancement lie. Distal cord showed T2 hyperintensity. (Right) Sagillal T7 C+ FS MR shows diffuse, patchy enhancement SI related 10 venous hypertensive myelopathy in this patient with Cognard V posterior fossa dural Avr with intraspinal venous drainage.

II 7 22

Dural A-V Fistula {Brain}

INTRAMEDULLARY

Arterial Infarction

LESION, DIFFUSE/ILL-DEFINED

ENHANCEMENT

Spinal Cord Metastases

rs

(LeFt) Sagittal T I C+ MR in a child with paraplegia after minor trauma shows mildly enlarged distal thoracic cord ~ with diFfuse enhancement. Exact etiology of the infarct was never established. (Right) Sagittal TI C+ MR shows glioma metastasizing

from the brain

stem e1 inferiorly into cord with multiple foci of patchy enhancement ~.

Astrocytoma (Left) Sagittal TI C+ MR shows large enhancing mass with long segment fusiform cord expansion. The enhancement is fairly homogeneous, with an irregular inferior margin. (Rigl1t) Sagittal TI C+ MR shows infiltrating brainstem and cervical cord mass with patchy, irregular

enhancement

=.

(LeFt) Sagittal TI C+ MR shows case of myelopathy fof/owing chest radiograph for head and neck squamous cell carcinoma. Note diffuse patchy cord enhancement ~ with expansion and fatty marrow replacement in the spine. (Right) Sagittal TI C+ MR shows diffuse patchy enhancement of the cord and pia II] in a patient with fever, CSF pleocytosis, and bacteremia.

II 7 23

INTRAMEDUllARY LESION, RING/PERIPHERAL ENHANCEMENT

DIFFERENTIAL DIAGNOSIS Ql

c: 0I/)

Common • Multiple Sclerosis, Spinal Cord • Astrocytoma, Spinal Cord • Ependymoma, Cellular, Spinal Cord Less Common • Metastases, Spinal Cord Rare but Important • Cysticercosis • Abscess/Myelitis, Spinal Cord • Epidermoid Tumor, Acquired

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Look for adjacent vertebral or disc abnormalities as a source of infection • Assess for supratentorial enhancing lesions Helpful Clues for Common Diagnoses • Multiple Sclerosis, Spinal Cord o Enhancement may be homogeneous, nodular, or peripheral • During acute or subacute phase & lasts 1-2 months • Does not reflect disease progression • Astrocytoma, Spinal Cord o Enhancement is characteristic • Mild/moderate ~ intense enhancement • Partial ~ total • Infiltrating ~ well-delineated • Enhancing area is target for biopsy o Asymmetric, can be exophytic

Multiple Sclerosis, Spinal Cord

II 7 24

=.

Sagittal T7 C+ MR shows faint ring enhancement of plaque at the C4-S level of the cord

• Ependymoma, Cellular, Spinal Cord o Avid, sharply delineated enhancement (50%) o Central> eccentric location o Polar or intratumoral cysts (50-90%) o Hemorrhage T1 hyperintense Helpful Clues for Less Common Diagnoses • Metastases, Spinal Cord o Focal enhancing cord lesion(s) with extensive edema o Lesions < 1.5 cm & well-circumscribed o Hemorrhagic mets from thyroid CA, melanoma show T2 hypointensity Helpful Clues for Rare Diagnoses • Cysticercosis o Peripheral cyst enhancement o Cord pial surface enhancement & arachnoiditis o Adjacent acute/chronic inflammatory cell infiltrate, "cysticercal abscess" • Abscess/Myelitis, Spinal Cord o Irregular ring-enhancing intramedullary lesion with cord expansion o ± Restricted diffusion o T2 hyperintensity from abscess core & surrounding edema • Epidermoid Tumor, Acquired o Isointense to CSF/cord on T1WI; iso-/hyperintense to CSF on T2WI; more hyperintense than CSF on DWI o Absent or faint peripheral enhancement o Think infected cyst if prominent enhancement

Astrocytoma, Spinal Cord

a fusiform hypoinlense intramedullary mass within the thoracic spinal cord with heterogeneous rim enhancement ~.

Axial T7 C+ FS MR demonstrates

INTRAMEDULLARY

LESION, RING/PERIPHERAL

ENHANCEMENT

~ ~

Q)

Ependymoma,

Cellular, Spinal Cord

Metastases,

3

Spinal Cord

CD (Left) Axial T1 C+ MR shows a moderalely, helerogeneously enhanced

mass

m that causes

central

Cl.

c: Q)

-<

cord expansion. Enhancemen/ degree and pattern is variable in cord ependymomas. (Right) Sagiltal T1 C+ FS MR shows focal inlramedullary enhancement within the distal cord & slighl expansion of Ihe conus medullaris 81.

(Left) Sagillal T1 C+ MR shows mullicysUc parenchymal

involvement

of

cervical cord by neurocysticercosis ID.. Note both cyslic & solid components with mild curvilinear

enhancement

r..:=.

(Right) Coronal T1 C+ MR

shows cord abscess with inlernal hypoin/ensity & thick peripheral enhancement. Cord swelling & extensive inlramedullary edema mimics tumor. There are no adjacent vertebral or disc abnormalities to suggest hematogenous distribution.

Abscess/Myelitis,

Spinal Cord

Epidermoid

Tumor, Acquired (Left) Sagillal T1 C+ MR shows case of tuberculosis producing a spinal cord abscess. The granulomalOus abscess demonstrates avid ring enhancement ~ with

central low signal intensity. A compression fracture ~ is nOlcd. (Right) Axial T1 C+ FS MR demonslrates a subtle ovoid lesion nestled within the cauda equina, isointense to conus. There is sublle peripheral enh,1ncemenl of Ihis lesion surrounded by nerve roots.

=

II 7 25

INTRAMEDUllARY

LESION, 11 HYPOINTENSE,

DIFFERENTIAL DIAGNOSIS Ql

c: Co III

Common • Instrumentation/Implants • Contusion-Hematoma, Spinal Cord • Cavernous Malformation, Spinal Cord Less Common • Cysticercosis • Type II AVM Rare but Important • Diastematomyelia

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Assess for post-surgical changes • Flow voids suggest vascular lesion • Associated vertebral body anomalies in diastematomyelia Helpful Clues for Common Diagnoses • Instrumentation/Implants o Intrathecal & epidural catheters allow infusion of anesthetics o Syringomyelia (hindbrain herniation or post-traumatic) treated with shunting into subarachnoid, peritoneal or pleural spaces o Complications: Infectious/inflammatory process, misplacement, cord or nerve injury, CSF leak, & spinal hematoma • Contusion-Hematoma, Spinal Cord o Acute contusion is Tl iso-/ hypointense o Blood products hypointense on T2 & T2* GRE sequences

Instrumenta

II 7 26

tion/I mplan ts

Sagillal TI WI M R shows a linear TI hypointense catheter within the cervical syrinx cavity Ill. Susceptibility artifact at the entry site of the catheter is alsoseen~.

o

12 HYPOINTENSE

± Cord swelling

• Cavernous Malformation, Spinal Cord o Tl & T2 heterogeneous due to blood products of varying ages o T2 hypointense rim (hemosiderin) o No edema unless recent hemorrhage o No prominent vascular flow voids or nidus Helpful Clues for Less Common Diagnoses • Cysticercosis o Focal cystic lesion(s) with or without syrinx cavity o T2 hypointensity may be due to cyst wall degeneration with calcification o Peripheral cyst enhancement • Type II AVM o Intramedullary nidus with dorsal subpial extension o Cord enlargement with heterogeneous Tl/T2 signal due to blood products & flow voids o Intra-/perinodal aneurysm in 40% • Subarachnoid is most common symptom Helpful Clues for Rare Diagnoses • Diastematomyelia o Type 1 has separate dural sac & arachnoid space, more common • Iso-/hypointense spur (osseous or fibrous) o Type 2 has a single dural sac & arachnoid space • ± Iso-/hypointense fibrous spur o Two hemicords with or without syringohydromyelia (50%)

Contusion-Hematoma,

Spinal Cord

Sagittal TlWI MR shows isointense/slightly hypointense signal in the cord rhere is isoinlense soft. tissue in the ventral epidural space E2 representing disc

I:m.

extrusion &/or epidural hemorrhage.

INTRAMEDULLARY

LESION, 11 HYPOINTENSE,

CJl

12 HYPOINTENSE

"'C

::J CD

~ ~ OJ Contusion-Hematoma,

Spinal Cord

Cavernous Malformation,

3

Spinal Cord (Left) Sagittal T2WI MR shows severe flexion injury with subluxation of C5 more than 50% over C6 body, flexion deformity, and widened posterior elements.

CD DC

OJ

-<

There is severe cord compression and cord hemorrhage~. of the anterior

Disruption longiwdinal

ligament is seen as hyperintensity~. (Right) Sagittal T1 WI MR shows a well-defined focus of predominately low signal within the left posterior aspect of the caudal medulla

r:i:I.

Cysticercosis

Cysticercosis (Left) Sagittal T2WI MR shows 2 focal intramedullary areas of slightly decreased signal r:i:I within the extensive

area of cord edema

~ (Right) Sagillal T1WI MR shows a focal cystic mass r:i:I involving distel/thoracic cord,

with fusiform

expansion.

cord

Without the

concomitant

brain

involvement,

the differential

of the cord lesion would be primarily

inuamedullary

tumor.

Diastematomyelia (Left) Coronal T2WI FS MR shows various stages of degradation from fluid-like cavity in the conus lip to methemoglobin SlIO low signal on all pulse sequences

=-

reflecting

hemosiderin

There are multiple

~.

serpentine

intradural flow voids, particularly about the dorsal distal cord [;>~.(Right) Axial T2WI MR shows marrow-filled osseous spur at L I ~ separating dural sacs with 2 hemicords. Focal hydromyelia is seen in the left hemicord r:i:I.

II 7 27

INTRAMEDULLARY

LESION,

DIFFERENTIAL DIAGNOSIS CIl

c: c.

lf)

Common • CSF Flow Artifact • Syringomyelia • Multiple Sclerosis, Spinal Cord • Contusion-Hematoma, Spinal Cord • ADEM, Spinal Cord • Ependymoma, Cellular, Spinal Cord • Astrocytoma, Spinal Cord • Hemangioblastoma, Spinal Cord Less Common • Type II AVM • Cavernous Malformation, Spinal Cord • Abscess/Myelitis, Spinal Cord

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Prominent flow voids seen with type II AVM & hemangioblastomas Helpful Clues for Common Diagnoses • CSF Flow Artifact o Caused by • Time of flight loss • Flow-related enhancement • Varied turbulent flow velocities/directions - rapid dephasing, signal loss, "intravoxel dephasing" o Artifacts propagate across cord, subarachnOid space o Most common in thoracic spine o Especially common in pediatric patients

11 HYPOINTENSE

• Syringomyelia o Expanded cord with non enhancing dilated or beaded cystic cavity • Multiple Sclerosis, Spinal Cord o Unlike supratentorial lesions, cord lesions are rarely visible as Tl hypointense • Contusion-Hematoma, Spinal Cord o Acute contusion appears iso-/hypointense with cord swelling o Hematoma later hyperintense 2 metHB • ADEM, Spinal Cord o Multifocal hypo intensity & slight cord swelling • Ependymoma, Cellular, Spinal Cord o Iso- or slightly hypointense to spinal cord with polar or intratumoral cysts (50-90%) o Fusiform cord enlargement • Astrocytoma, Spinal Cord o Multisegmental, usually < 4 segments o Hypo-/isointense eccentric, infiltrative solid portion, indistinct margins ± syrinx • Hemangioblastoma, Spinal Cord o Cystic lesions with enhancing nodule & extensive surrounding edema 0

Helpful Clues for Less Common Diagnoses • Type II AVM o Enlarged cord with heterogeneous signal 2 blood products & flow voids • Cavernous Malformation, Spinal Cord o Speckled "popcorn" appearance 2 varying ages of blood products • Abscess/Myelitis, Spinal Cord o !II-defined hypointensity, expanded cord

0

0

CSF Flow Artifact

II 7 28

Sagittal T7 WI MR shows vague mixed hyper-, hypoinlensily propagating across thoracic subarachnoid space and cord due 10 CSF pulsavon artifact.

=

Coronal TI WI MR shows dilated cysvc lesion mildly expanding the cord wilh septavons PJ:ll. There may be surrounding gliosis, myelomalacia, cord lethering, edema, or arachnoidal adhesions.

INTRAMEDULLARY

LESION, 11 HYPOINTENSE

~ ..., OJ

Multiple Sclerosis, Spinal Cord

3

ADEM, Spinal Cord (Left) Axial T IWI MR shows an eccentrically located intramedullary lesion compatible with a demyelinating plaque. T1 hypointense plaques are rarely visible. 10-20% cases have isolated spinal cord disease. Cord edema resolves after 6-8 weeks, and cord atrophy is seen in the late stage. (RighI) Sagit/al TI WI MR shows vague hypointensity spanning the cervical cord with mild

=-

expansion

Astrocytoma, Spinal Cord

ct> c. c OJ

-<

D].

Type II AVM (Left) Sagit/al T1WI MR

shows a heterogeneous hypointense intramedullary mass expanding the cervical cord (Rig/,t) Sagittal T I WI MR shows prominent flow voids !:ll related to an intramedullary AVM nidus.

=.

There is often extension

to

the dorsal subpial surface. 40% of patients have aneurysms of feeding vessels. These findings are associated with cutaneous angiomas, Klippel-Trenaunay-Weber, & Rendu-Osler-Weber syndromes.

Cavernous Malformation, Spinal Cord

Abscess/Myelitis,

Spinal Cord (Left) Sagit/al TI WI MR shows a heterogeneously

=

hypoinlense intramedullary lesion with a speckled appearance due to blood products of varying ages. (Right) Sagit/al TlWI MR shows cervical cord swelling with internal hypointensity

=-

often seen in inflammatory lesions. Extensive intramedullary edema mimics a cord tumor. No adjacent vertebral or disc abnormalities that suggest a local inFectious source were noted, implying hematogenous distribution.

II 7 29

INTRAMEDUllARY

LESION, 12 HYPERINTENSE,

DIFFERENTIAL DIAGNOSIS Q)

c: a.

C/)

Common • Multiple Sclerosis, Spinal Cord • Neuromyelitis Optica • Secondary Acute Transverse Myelitis • Acute Transverse Myelitis, Idiopathic • Contusion-Hematoma, Spinal Cord • Ependymoma, Cellular, Spinal Cord • Astrocytoma, Spinal Cord • Type I DAVF less Common • Hemangioblastoma, Spinal Cord • ADEM,Spinal Cord • Infarction, Spinal Cord • Viral Myelitis Rare but Important • Metastases, Spinal Cord • Abscess/Myelitis, Spinal Cord • Vitamin Bl2 Deficiency, Spinal Cord

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Evaluate supratentorially, including cranial nerves • Hemorrhagic products & flow voids can be seen in certain lesions

II 7 30

Helpful Clues for Common Diagnoses • Multiple Sclerosis, Spinal Cord o TI hypointensity may represent axonal loss, gliosis, white matter atrophy, & therefore motor disability o Cervical cord TI relaxation time may be influenced by tissue damage upstream (i.e., cerebral damage) o Well-circumscribed T2 hyperintense lesions (complete demyelination) vs. ill-defined (partial demyelination) o Wedge-shaped lesions with apex directed centrally • Neuromyelitis Optica o Revised diagnostic criteria (99% sensitive, 90% specific) o Myelitis: Longitudinally extensive cord lesion, 3 or more segments in length o Optic neuritis o Onset brain MR nondiagnostic for MS o Seropositivity for neuromyelitis optica immunoglobin G

11 ISOINTENSE

• Targets aquaporin 4 water channel • Secondary Acute Transverse Myelitis o T2 hyperintense lesion with mild cord expansion o No significant enhancement o Mild Tl hyperintensity due to petechial hemorrhage o Etiologies: Collagen vascular disease, infectious/post -in fectious, post-vaccination, post-irradiation, AVM, para neoplastic • Acute Transverse Myelitis, Idiopathic o Smooth cord expansion < T2 signal abnormality o T2 hyperintensity more than 2 vertebral segments in length o Central gray matter surrounded by edema, "central dot sign" • Contusion-Hematoma, Spinal Cord o Acute contusion: TI iso-/hypointense, T2 hyperintense with cord swelling o Hemorrhage TI hyperintense with metHB, blooming on GRE sequences o ± Traumatic disc herniation, osseous or vascular injury • Ependymoma, Cellular, Spinal Cord o T2 hyperintense, Tl iso-/slightly hypointense o Polar & intratumoral cysts (50-90%) o Syrinx o Hemosiderin cap (20-64%) o Central canal widening (20%) & posterior vertebral scalloping • Astrocytoma, Spinal Cord o T2 hyperintense, solid portion TI iso-/hypointense o Usually < 4 segments o Diffuse tumor infiltration, absence of hemorrhage, & intrinsic neoplastic syrinx cavity favor astrocytoma over ependymoma o Concurrent combination of intramedullary cord tumor & nerve sheath tumor is highly suggestive of NFl • Type I DAVF o Flame-shaped central edema spares the periphery o Low peripheral T2 signal is compatible with venous hypertensive myelopathy o Cord is enlarged & TI hypointense

INTRAMEDUllARY

lESION,

12 HYPERINTENSE,

11 ISOINTENSE

(J)

"C

::J

11l

o o o

Multiple small vascular flow voids are seen on the cord pial surface ± Patchy cord enhancement Most commonly at level of conus

Helpful Clues for less Common Diagnoses • Hemangioblastoma, Spinal Cord o Small lesions T2 hyperintense/Tl hypointense o Syrinx> 50%, hyperintense to CSF o Lesions> 2.5 cm show flow voids o ± Peritumoral edema • ADEM, Spinal Cord o Multifocal TI hypointense/T2 hyperintense lesions with slight cord swelling o Little mass effect or edema o Concomitant brain involvement • Infarction, Spinal Cord o T2 hyperintensity involving the gray matter ± adjacent white matter o Increased T2 signal in the adjacent anterior vertebral body or in deep medullary portion near end plate o Cord enlargement in acute phase o More common in thoracic cord because of arterial border zone • Viral Myelitis o Expanded cord with TI hypo intensity & diffuse T2 hyperintensity o Long, contiguous segmental involvement o Acute myelopathy Helpful Clues for Rare Diagnoses • Metastases, Spinal Cord

gray-white boundary segmen!Sin length.

=. The lesions span the

& are less /han 2

vertebral

;:l. ~

llJ

3

a. c llJ

-<

SELECTED REFERENCES 1.

2.

3.

Sagiltal T2WI MR shows ill-defined T2 hyperintense

lesions in the cervical cord

Enlarged cord with diffuse T2 hyperintensity o Rarely, syrinx or hemorrhagic products (i.e., thyroid, melanoma) o Well-circumscribed < 1.5 cm enhancing lesion • Abscess/Myelitis, Spinal Cord o Abscess core appears TI hypointense/T2 hyperintense with surrounding edema o Idiopathic or hematogenous source in adults; direct extension from dysraphism in children • Vitamin BIZ Deficiency, Spinal Cord o Axial T2 show "upside-down V-shaped" hyperintensity along dorsal columns o Accumulation of methylmalonic acid thought to cause myelin toxicity o Subacute combined degeneration also occurs in the setting of some types of severe anemia o Neurologic findings may precede the anemia o Treatment with parenteral BI2 may improve symptoms, but imaging abnormalities may not completely resolve o

Wingerchuk OM et al: Revised diagnostic criteria for neuromyelitis optica. Neurology. 66(10):1485-9, 2006 Vaithianathar L et al: Magnetic resonance imaging of the cervical spinal cord in multiple sclcrosis--a quantitative TI relaxation time mapping approach. J Neurol. 250(3):307-15,2003 Losseff NA et al: Tl hypointensity of the spinal cord in multiple sclerosis. J Neurol. 248(6):517-21, 2001

Axial T2WI MR shows long segment of central cord T2 hyperintensity 1:1:1 & mild diffuse cord enlargement. Extensive cord involvement is distinct from more focal abnormalities typically seen wilh multiple sclerosis.

II 7 31

INTRAMEDULLARY

LESION, T2 HYPERINTENSE, T1 ISOINTENSE

Secondary Acute Transverse Myelitis Ql

c: c..

en

Acute Transverse Myelitisr

Idiopathic

(Left) SagiHal T2WI MR shows pattern of dural fistula hypertensive myelopathy: Cenlral cord hyperinlensity EI sparing the cord periphery. Multiple flow voids ~ on Ihe dorsal cord surface are distended & arterialized veins. Fistula itself is not visualized & is peripherally localed in Ihe dural rool sleeve. (Right) Sagitlal T2WI MR shows a long segmenl of central edema

with relative sparing

of the periphery within the Ihoracic cord =:I.

Astrocytoma,

Spinal Cord

(Left) Sagittal T2WI MR shows neoplastic enlargement portion

with

extending

a

solid

from C2-]

to C5-6 =:I. Hyperinlense cysts cap the rostral & caudal ends. (Right) Sagittal TI C+ MR demonslrales an extensive Tl isoimense, 72 hyperintense intramedullary lesion =:I Ihal expands the cord & extends from pons into thoracic cord. Septated neoplastic syrinx m is observed & may extend Ihe entire length of the spinal cord. Laminectomies are a/50 seen 8J.

'-=

Type I DAVF (Left) Sagiltal T2WI MR shows central cord T2 hyperintensily which spares the cord periphery due to venous hypertension.

=

There are multiple intradural

the arterialized venous plexus =:I. (Right) SagiHal T2WI MR shows diffuse cervical cord expansion & edema within Ihe cord 8:1. There is signal heterogeneity of Ihe tumor wilh cenlral irregular hyperintense cyst =:I. The edema Iypically spares the cord periphery.

'-=

II 7 32

serpentine

ffow voids from

Hemangioblastoma,

Spinal Cord

INTRAMEDULLARY

ADEM, Spinal Cord

LESION,

T2 HYPERINTENSE,

Infarction,

11 ISOINTENSE

Spinal Cord (Left) Sagittal TI WI MR

shows conus expansion & decreased T llincreased T2

=.

signal intensity Conus expansion & T2 hyperintensity can be seen with a variety of neoplastic or inflammatory diseases. (Right) Axial T2WI MR shows cord expansion & hyperintensity. Only a small part of the peripheral cord is spared, probably with flow from small radicular collateral vessels. The slightly more hypoinlense center may represent hemorrhage.

Viral Myelitis

Metastases,

Spinal Cord (Left) Axial T2WI MR shows increased T2 signal in swollen, edematous cord. Contiguous segmental involvement is most common. In this case of herpes zoster myelitis there is abnormal signal extending into the dorsal ganglion ~ (Right) Sagittal TlWI MR shows an oval isointense lesion with a subtle

hyperintense rim ~

in this

patient with lung cancer metastases.

Abscess/Myelitis,

Spinal Cord

Vitamin 812 Deficiency,

Spinal Cord (Left) Sagittal T2WI MR shows hyperintense epidural mass with peripheral low signal due to abscess & extension into adjacent cord with pyogenic myelitis. There is adjacent cord edema m. (Right) Sagittal STIR MR shows hyperintensity along mildly enlarged posterior cord from foramen magnum to C7 T2 hyperintensity confined to dorsal columns is highly suggestive of this diagnosis. Symptoms improve with B 12 treatment, but imaging may not completely resolve.

=

=.

II 7 33

INTRAMEDULLARY

LESION,

DIFFERENTIAL DIAGNOSIS Ql

c: Co

CIl

Common • Contusion-Hematoma, Spinal Cord • Tumor Hemorrhage/Proteinaceous Cyst o Ependymoma, Cellular, Spinal Cord o Astrocytoma, Spinal Cord o Metastases, Spinal Cord • Cavernous Malformation, Spinal Cord Less Common • Dermoid and Epidermoid Tumors • Lipoma • Infection, Cryptococcoma, Tuberculoma • Melanocytoma Rare but Important • Intramedullary AVM

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • T1 hyperintensity can be due to hemorrhage, fat, melanin • Look for associated vertebral body or neural arch abnormalities & mass effect on regional structures

II 7 34

Helpful Clues for Common Diagnoses • Contusion-Hematoma, Spinal Cord o Tl hyperintensity due to methemoglobin • Early T2 hypo intensity caused by deoxyhemoglobin in the local hypoxic state of the injured segment o ± Traumatic disc herniation & vascular injury o Increase in spinal cord edema during the early period after injury & comparatively static intramedullary hemorrhage • Ependymoma, Cellular, Spinal Cord o Enhancing cord mass with hemorrhage o Fusiform cord enlargement with central canal widening in 20% o Polar or intratumoral cyst (50-90%) o More often central growth pattern o More often in the lower thoracic cord • Astrocytoma, Spinal Cord o Cord expansion • Multisegmental, usually < 4 segments • Holocord involvement more often with pilocystic astrocytoma • Can be asymmetric or exophytic

11 HYPERINTENSE

Minority of cases T1 hyperintensity due to methemoglobin o Enhancement is characteristic • Mild => intense, partial => total, infiltrating => sharply delineated o ± Cyst/syrinx (slightly hyperintense to CSF) • Metastases, Spinal Cord o Hemorrhagic mets, such as thyroid & melanoma metastases • Growth of primary spinal melanoma if slower & survival is longer o Focal enhancement • Cavernous Malformation, Spinal Cord o Speckled heterogeneous lesion with blood products of varying ages • T2 hypo intense rim 2° hemosiderin • Minimal to no enhancement o Lesions abut the pial surface o Angiographically occult o Clinical presentation ranges from acute neurological decline 2° hemorrhage to chronic progressive myelopathy due to microhemorrhages & gliotic reaction to blood products o

Helpful Clues for Less Common Diagnoses • Dermoid and Epidermoid Tumors o Dermoid • Well-demarcated isodense mass ± foci of fat signal/density & calcification • Fat Tl hyperintensity is most specific for dermoid but least common • Congenital lesion presenting in young patients o Epidermoid • Hyperintense on OWl, T1 isointense to CSF, mildly T2 hyperintense • Acquired or congenital, slower growing, present in 3rd to 5th decade o Extramedullary (60%) > intramedullary (40%)

Mild peripheral enhancement; however, more intense enhancement if infected • Lipoma o Homogeneously T1 hyperintense intradural nonenhancing mass o Intradural lipoma can invaginate into the cord substance • Weakness & sensory abnormality at lesion level • Normal overlying skin o

INTRAMEDUllARY

lESION,

• ± Canal widening & dysraphism Terminal lipoma can tether the cord with extension through dorsal dysraphism into subcutaneous fat • Tethered cord syndrome: Bowel/bladder dysfunction, lower extremity motor/sensory abnormality • Cutaneous stigmata frequently seen, foot deformity, scoliosis • ± Syrinx • Infection, Cryptococcoma, Tuberculoma o Tuberculoma • Iso-/hyperintensity on Tl WI at site of granuloma • Iso-/hypointense T2 rim with hyperintense center (caseous necrosis), surrounding hyperintense edema o Cryptococcus has a respiratory entry • CNS manifestation (meningitis/ men ingoencepha Iitis) most common because CSF does not have anticryptococcal factors present in serum • Arachnoiditis ± mass lesions, intramedullary mass lesions (abscess or granuloma), extradural lesion • Slightly Tl hyperintense (fibrosis & inflammatory cellular infiltrates), T2 hypointense with hyperintense focus & surrounding hyperintense edema • Intense solid or ring-like enhancement • Melanocytoma o Primary pigmented neoplasm, involving cord or meninges • Can be locally invasive

Tl/T2 shortening by proton-proton dipole-dipole interaction o Heterogeneous enhancement o Highest concentration of melanocytes occurs in the spinal leptomeninges in the upper cervical level o Meningiomas & schwannomas may RARELYdemonstrate Tl hyper intensity due to melanin o

o

Contusion-Hematoma,

Spinal Cord

Sagittal T7WI MR shows cervical kyphosis and traumatic spondylolisthesis of C3 relalive to C4. There is a burst fracture of C4 vertebral body. A large hematoma II::)] is seen in the spinal cord.

T1 HYPERINTENSE

Helpful Clues for Rare Diagnoses

• Intramedullary AVM o Prominent vascular flow voids leading to & from high flow lesion • Compact or diffuse nidus with aneurysms (20-40%) o Heterogeneous Tl/T2 signal due to blood products o T2 hyperintensity in the cord due to edema, gliosis, ischemia o Subarachnoid hemorrhage, compression, vascular steal • Myelopathy (acute/progressive), pain

SELECTED ].

2. 3.

REFERENCES

Leypold BG el al: The early evolution of spinal cord lesions on MR imaging following traumatic spinal cord injury. AJNR Am J Neuroradiol. 29(S):1012-6, 2008 Gilltasli NZ et al: MRI findings of intramedullary spinal cryptococcoma. Diagn Interv Radiol. 13(2):64-7,2007 Spetzler RF et al: Modified classification of spinal cord vascular lesions. J Neurosurg. 96(2 Suppl):14S-S6, 2002

Ependymoma,

Cellular, Spinal Cord

Sagittal T7WI MR shows fusiform expansion of the cervicothoracic cord with slight heterogeneous signal

=.

II 7 35

INTRAMEDULLARY

(l)

c: a. (/)

LESION,

11 HYPERINTENSE

(Left) Sagittal T7WI MR shows a lobulated hyperintense intramedullary mass expanding the distal cord The T I hyperintensity refleclS blood produclS. (Right) Sagittal T7 WI MR shows a hemorrhagic spinal cord astrocytoma. There is a fusiform hypoinlense intramedullary mass within the thoracic spinal cord extending to the conus

=.

=.

(Left) Sagittal T7 WI MR shows an expansile intramedullary mass Astrocytomas cause fusiform cord expansion, although they can be asymmetric or exophytic. Methemoglobin in a minority of cases can result in T1 hyperintensity. (Right) Sagillal T2WI MR in the

=.

same patient shows the mass m. Its superior margin ;s at T I, and the inferior margin is at T8 P:?:l. There may be an associated cyst/syrinx, which is slightly hyperintense to CSF.

Metastases, Spinal Cord (Left) Sagittal T7WI MR shows hypointense vertebral body extradural metastases 81as well as a rounded hyperintense intramedullary lesion in the conus Nigh signal intensity likely represents hemorrhage. (Right) Sagittal T7 WI MR shows focal high signal

=.

within

upper cervical

cord at

C 1 level from the cavernous malformation. There is linear high signal extending inferiorly from a more recent cord hemorrhage

=.

II 7 36

Cavernous Malformation, Spinal Cord I

INTRAMEDULLARY

en

LESION, 11 HYPERINTENSE

~. ::l CIl

Dermoid

and Epidermoid

Tumors (Left) Sagittal T7 WI MR shows a lobulaled lesion involving lhe dislal cord and conus medullaris. There are patchy and curvilinear areas of T7 hyperinlensily representing lipid malerial. (Right) Sagittal TlWI MR shows a dorsal T7

=

hyperintense intradural

=

subpial lipoma with mild spinal cord distortion.

Lipoma

Infection,

Cryptococcoma,

Tuberculoma (Left) Axial T7WI MR shows a dorsal hyperintense intradural subpial lipoma = distorling lhe cord. Note lhe intimate relationship of the lipoma with dorsal spinal cord E:I due to premature dysjunction during neural lUbe formation. (Right) Sagiltal T7WI MR shows dorsal dermal sinus tract with a large intradural mass 81 involving distal cord with caudal extension.

=

Post·conlrasl

images (not

shown) reveafenhancernenl surrounding a cord abscess & of a sinus tract.

Melanocytoma (Left) Sagittal T7 WI MR shows a complex signal intramedullary mass involving

mid-thoracic

cord

wilh foci of hyperinlensity Ell. NOle small CYSI ~ along cephalad margin & superior cord syrinx (Right) Sagittal T7WI MR shows cord hemorrhage of varying slages of degradation, including a fluid-like cavity in lheconus=. melhemoglobin 8l & low signal reflecting hemosiderin ~. Note serpentine

=.

intradural

flow voids about

lhe dorsal distal cord~_

II 7 37

CORD LESION, 12 HYPERINTENSE, VENTRAL

DIFFERENTIAL DIAGNOSIS Gl C

a. m

Common • Multiple Sclerosis, Spinal Cord • Contusion-Hematoma, Spinal Cord • Infarction, Spinal Cord • Spondylotic Myelopathy Less Common • Spinal Cord Herniation Rare but Important • Viral Myelitis • Toxin Exposure • Amyotrophic Lateral Sclerosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Axial T2WI: Useful to localize lesion center in relationship to spinal cord long tracts Helpful Clues for Common Diagnoses • Multiple Sclerosis, Spinal Cord o STIR MR is sensitive for detecting demyelinating lesions o Ill-defined = partial demyelination; well-defined = complete demyelination • Contusion-Hematoma, Spinal Cord o Acute contusion shows T2 hyperintensity with susceptibility artifact from blood products on GRE o STIRdetects marrow edema & ligamentous injury • Infarction, Spinal Cord

T2 hyperintensity in gray matter ± adjacent white matter, classically anterior horn cells o Vertebral body infarct with increased T2 marrow signal in the anterior vertebral body/deep medullary portion near the endplate • Spondylotic Myelopathy o Pathophysiologic factors may be static mechanical, dynamic mechanical, & spinal cord ischemia o

Helpful Clues for Less Common Diagnoses • Spinal Cord Herniation o Focal anterior cord displacement through a ventral dural defect with expansion of dorsal subarachnoid space o Often in mid-thoracic spine with cord deformity Helpful Clues for Rare Diagnoses • Viral Myelitis o Disease of lower motor neurons that affects the gray matter of the spinal cord, specifically ventral horns o Includes poliomyelitis • Toxin Exposure o Reported cases of T2 hyper intensity & enhancement in the anterior horns & lumbar nerve roots after heroin & amphetamine exposure • Amyotrophic Lateral Sclerosis o Earliest manifestations of ALSon imaging may be diffusion restriction

Multiple Sclerosis, Spinal Cord

II 7 38

Axial

T2WI MR reveals multiple

intramedullary demyelinating lesions

T2 hyperintense

=.

=-

Sagittal T2WI MR shows intramedullary hyperintensity due to edema & an ovoid hypointense focus

a

compatible WiU1 blood products. This cord contusion is due to a traumatic disc protrusion ~.

CORD LESION, 12 HYPERINTENSE, VENTRAL

Infarction, Spinal Cord

Infarction, Spinal Cord (Left) Axial T2Wf MR shows central cord hyperintensity Ell. (Right) Sagittal OWl MR shows {ocal hyperintensity within the cord due to restricted diffusion and very low signal from the remainder of spinal soft tissues.

=

Spinal Cord Herniation (Left) Sagittal T2WI MR shows a disc herniation at C4-C5 that produces cord compression and (ocal abnormal intramedullary T2 signal correlating with clinical myelopathy. (Right) Sagittal T2Wf MR shows thoracic idiopathic transdural cord herniation. There is focal anterior displacement of the upper thoracic cord

=-

abulling

the posterior

vertebral body margin Ell with very sharp angulation.

Viral Myelitis

Amyotrophic lateral Sclerosis (Left) Axial T2WI MR shows high signal intensity in the ventral aspect of the distal thoracic cord & conus meduJ/aris, incfuding involvement of the central gray matter~. (Right) Axial OWl MR shows restricted diffusion in the corticospinal/pyramidal tracts extending caudally from the precentral fmotor) gyri through the midbrain (not shown) & into the medulla. Patients with ALS display fasciculations, atrophy of extremities, & denervation pattern on [MG.

=

II 7 39

CORD lESION, 12 HYPERINTENSE, DORSAL

DIFFERENTIAL DIAGNOSIS Q)

c: a.

en

Common • Multiple Sclerosis, Spinal Cord • Contusion-Hematoma, Spinal Cord less Common • Subacute Combined Degeneration o Copper Deficiency o Nitrous Oxide Misuse • HIV • Sarcoidosis • Cord Wallerian Degeneration Rare but Important • Neurosyphilis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Intracranial periventricular, subcallosal, cerebellar & brainstem lesions in MS • GRE sequences helpful to evaluate for hemorrhagic products in cord contusion Helpful Clues for Common Diagnoses • Multiple Sclerosis, Spinal Cord 090% of cases have intracranial lesions o 10-20% cases have isolated spinal cord disease o Cervical cord is most commonly affected • Acutely, central enhancement of peripheral T2 hyperintense lesion • Enhancement duration 1-2 months • Cord edema lasts 6-8 weeks • Dorsolateral aspect of cord involving both the white matter and adjacent gray matter • Cord atrophy in late stage • Contusion-Hematoma, Spinal Cord o Acute: Cord swelling & T2 hyper intensity o May see hemorrhagic products within cord, fracture, & soft tissue injury o May see traumatic disc herniation o STIR sequence is helpful to assess marrow edema and ligamentous injury

II 7 40

Helpful Clues for less Common Diagnoses • Subacute Combined Degeneration o T2 hyperintensity confined to dorsal ± lateral columns o Lower cervical and upper thoracic cord

Focal cord swelling of myelin tubes progresses to larger areas of myelin vacuolization o Mild cord enlargement ± mild dorsal column enhancement o Occurs in setting of some types of severe anemia (e.g., megaloblastic anemia) • Methylmalonic acid accumulation causes myelin toxicity • Neurologic findings may precede anemia • Treatment may improve symptoms but imaging abnormalities may not completely resolve o Copper Deficiency • Spastic gait and sensory ataxia • Etiologies include malabsorption, partial gastrectomy, and hyperzincemia • Long segment of symmetric increased T2 signal in the dorsal midline cervical and thoracic cord • Imaging findings may be reversible with normalization of serum copper o Nitrous Oxide Misuse • May result in subacute combined degeneration with symptoms ranging from paresthesias to autonomic dysfunction • Nitrous oxide inhibits the active form of vitamin B12 • Toxicity is related to the patient's levels of vitamin B12 • Demyelination with T2 hyperintensity in the central posterior columns of the cord • Pathologically usually begins in thoracic cord • Myelopathy has been reported 2-6 weeks after nitrous oxide anesthesia • HIV o Most common imaging finding is atrophy o

(72%)

T2 hyperintensity involving white matter tracts laterally & symmetrically o May show patchy enhancement o Thoracic> cervical cord • Rostral extension from mid to lower thoracic cord with disease progression o Progressive spastic paraparesis with ataxia, urinary symptoms & sensory loss • Sarcoidosis o Focal or diffuse T2 hyperintensity & fusiform cord enlargement o

CORD

LESION, 12 HYPERINTENSE,

• Myelomalacia in late stages o Leptomeningeal & peripheral intramedullary mass-like enhancement o Lytic spine lesions o Male> female in spinal sarcoidosis • Cord Wallerian Degeneration o Post-traumatic: Increased T2 signal in dorsal columns above injury level & in lateral corticospinal tracts below the injury level • In lumbar or thoracic cord injury, the portion of dorsal columns that undergoes wallerian degeneration is smaller than in the case of a cervical injury • Size effect is a function of the number of axons damaged by the injury & somatotopic arrangement of ascending fibers in the dorsal column tracts • Corticospinal tract contains fewer axons in distal than proximal regions; therefore smaller in the lumbar region o Four stages of wallerian degeneration • 1: Physical degradation of axon with little biochemical change in myelin during first 4 weeks & results in no signal intensity abnormality • 2: At 4-14 weeks, myelin protein breakdown with intact myelin lipids (high lipid-protein ratio) results in hypointense T2 signal

o

• 3: At> 14 weeks, myelin lipid breakdown, gliosis, and changes in water content and structure results in T2 hyperintense signal • 4: Several years after injury, there is volume loss Late sequela of acute demyelinating lesions, i.e., MS

=

;:;. ~ OJ

3 CD

Cl. C

OJ

-<

Helpful Clues for Rare Diagnoses • Neurosyphilis o a.k.a., tabes dorsalis o Slowly progressive degenerative disease involving the posterior columns (i.e., demyelination) & posterior roots (i.e., inflammatory change with fibrosis) of the spinal cord o T2 hyperintensity and focal enhancement in the dorsal aspect of the cord o 3 stages: Preataxia, ataxia, & paralysis o Onset 20-30 years after the initial infection

SELECTED REFERENCES 1. 2.

Pema PJ et al: Myelopathy caused by nitrous oxide toxicity. AJNR Am J Neuroradiol. ] 9(S):894-6, 1998 Becerra JL et al: MR-pathologic comparisons of wallerian degeneration in spinal cord injury. AJNR Am J Neuroradiol. 16(1):125-33, 1995

Multiple Sclerosis, Spinal Cord

Multiple Sclerosis, Spinal Cord

Axial T2WI MR shows hyperintense intramedullary lesions with focal cord enlargement The dorsal horns are involved & there is local cord enlargement

DORSAL

Sagittal T2WI MR shows multiple T2 hyperintense foci The multiplicity of lesions along with the lack of edema or significant cord expansion is typical for a demyelinating disease.

=.

II 7 41

CORD LESION, 12 HYPERINTENSE,

Contusion-Hematoma, CIl

C Q.

lI)

Spinal Cord

(Left) Sagittal STIR MR shows a flexion dislocation injury of T11-12 81, burst fracture of L 1 ~ & compression fracture of L4 There is conus

=.

compression and distal cord contusion ~. (Right) Axial T2WI MR shows cord

compression It] and increased signal within the cord due to a contusion.

(Left) Sagittal T2WI MR shows C4-S discectomy and fusion with myelomalacia within the cervical cord ID. (Right) Axial T2WI MR displays T2 hyperintensity within dorsal spinal cord with a characteristic inverted V" or inverted" rabbit ears" appearance ~. /I

Subacute Combined (Left) Sagittal T2WI MR shows hyperintensity along a mildly enlarged posterior cervical cord extending from the foramen magnum to C7 (Right) Sagittal T2WI MR reveals abnormal T2 hyperintensity posteriorly

=.

=

within spinal cord from

primary HIV myelilis. These images are used with permission

from the

American Journal of Neuroradiology (AfNR).

II 7 42

Degeneration

DORSAL

Contusion-Hematoma,

Spinal Cord

CORD lESION,

HIV

12 HYPERINTENSE, DORSAL

Sarcoidosis (Left) Axial T2WI MR shows abnormal intramedullary hyperinlensily within the posterior cervical cord in a patient with II/V myelopathy. The pattern may appear identical to the findings seen from vitamin B 7 2 deficiency. (Right) Sagittal graphic demonstrates multiple intramedullary sarcoid granulomas 0 in the brainstem and upper cervical cord. eNS involvement is seen in 5 % of patients with sarcoidosis.

=

Sarcoidosis

Sarcoidosis (Left) Sagittal T2WI MR shows diffuse hyperintensity in the spinal cord, interspersed with isointense nodules There is mild cord expansion. (Righi) Sagittal T7 C+ MR reveals patchy & nodular

=.

intramedullary enhancement

=. Enhancement

pattern can vary from enhancing dural masses to leptomeningeal & peripheral & mass-like intramedullary enhancement. Enhancement ! with steroid treatment; there is a poor correlation with clinical response.

Cord Wallerian

Degeneration

Cord Wallerian

Degeneration (Left) Axial T2WI MR shows increased signal from the lateral aspect of the cord ~ due to waJlerian degeneration within the lateral corticospinal tracts. (Right) Axial T2WI MR shows increased signal from the lateral aspect of the cords below level of cord injury within the lateral corticospinal tracts. Above the level of injury, the dorsal columns are involved. Below the level of injury, the lateral corticospinal tracts are involved.

=

II 7 43

CORD

lESION,

12 HYPERINTENSE,

DIFFERENTIAL DIAGNOSIS Q)

c: a.

1Il

Common • Syringomyelia • Multiple Sclerosis, Spinal Cord • Acute Transverse Myelitis, Idiopathic • Infarction, Spinal Cord • Type I DAVF less Common • Acute Disseminated Encephalomyelitis, Spinal Cord • Viral Myelitis • Cavernous Malformation, Spinal Cord • Astrocytoma, Spinal Cord • Central Spinal Cord Syndrome • Radiation Myelopathy

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • T2 hypointensity ± susceptibility artifact on gradient echo recalled sequences to indicate hemorrhagic products • Abnormal enlarged flow voids along the surface of the cord suggest a vascular lesion

II 7 44

Helpful Clues for Common Diagnoses • Syringomyelia o Expanded cord with dilated or beaded cystic cavity & surrounding gliosis/myelomalacia o Contrast important to exclude tumor in complex cavitary lesion o Primary: Associated basilar invagination, Chiari 1 or 2 malformation o Secondary: Seen in 25% of cord injury • Extensive MR signal change in superior spinal cord parenchyma is ancillary sign of disease advancement in clinically progressive post-traumatic syringomyelia o "Cloak-like" pain & temporary sensory loss with preservation of position sense, proprioception, light touch • Multiple Sclerosis, Spinal Cord o Peripheral T2 hyperintensity with central enhancement (acute/subacute) classic • < 2 vertebral segments in length • < 1/2 cross-sectional area of cord, usually dorsolateral aspect • Cord atrophy • Cervical cord most often involved o May occur in any portion of cord

CENTRAL

Up to 33% may have isolated cord lesions • 90% have intracranial lesions o Oligoclonal bands in CSF in 90% • Acute Transverse Myelitis, Idiopathic o Both halves of the cord result in bilateral motor, sensory, & autonomic dysfunction • Defined sensory level • CSF pleocytosis or elevated IgG index o Long cord segment involvement (> 2 vertebral segments) with> 2/3 of cross-sectional area of cord o Central T2 hyperintensity with patchy eccentric enhancement • Infarction, Spinal Cord o Focal T2 hyperintensity in slightly expanded cord • Gray matter, adjacent white matter, or cross-sectional cord may be involved • Classically, the anterior horn cells show T2 hyperintensity • Focal hemorrhage seen as Tl hyperintensity/T2 hypointensity • Adjacent anterior vertebral body infarction o Thoracic cord most frequently involved because of arterial border zone o Restricted diffusion on DWI o Acute onset of myelopathy; motor signs predominantly • Type I DAVF o Enlarged T2 hyperintense distal cord with dilated pial veins • Intradural, extramedullary flow voids at level of conus o "Flame-shaped" edema spares cord periphery • Venous hypertension from pial vessel engorgement results in reduced tissue perfusion & cord ischemia o 80% patients are men in 5th or 6th decade presenting with progressive lower extremi ty weakness • Acute myelopathy due to venous thrombosis: Foix-Alajouanine syndrome o

Helpful Clues for less Common Diagnoses • Acute Disseminated Encephalomyelitis, Spinal Cord o Multifocal white matter lesions with little mass effect or vasogenic edema o Punctate, ring-shaped, or fluffy enhancement

CORD

lESION,

12 HYPERINTENSE,

Concomitant supratentorial involvement is characteristic • Cranial nerve involvement with ADEM to help differentiate from MS o Autoimmune process producing inflammatory reaction o Delay between clinical onset and appearance of imaging findings • Viral Myelitis o Either immune-mediated or direct viral invasion • Echovirus, Coxsackie, CMV, varicella-zoster, HSV,EBV,hepatitis o Central T2 hyperintensity with variable enhancement • Enlarged edematous cord with segmental continuous involvement • Central Tl hypointensity is higher than CSF • Cavernous Malformation, Spinal Cord o Well-defined lesion with hemorrhage of various ages o Speckled signal with peripheral T2 hypointense rim (hemosiderin) o Enhancement absent/minimal o No edema, unless acute hemorrhage o 50% thoracic, 40% cervical, 10% conus • Astrocytoma, Spinal Cord o T2 hyperintense enhancing infiltrating mass, expanding cord o Usually < 4 segments, holocord with pilocytic astrocytoma • Cervical> thoracic cord o Diffuse or partial enhancement o

CENTRAL

• Central Spinal Cord Syndrome o Diffuse disruption axons, especially within lateral columns of cervical cord (corticospinal tracts); central gray matter intact o Most common mechanism may be direct compression of cord by buckling of ligamenta flava into an already narrowed spinal canal o MR & pathology indicate that intramedullary hemorrhage is not a necessary feature, probably uncommon o Predominant loss of motor function in distal muscles of the upper limbs • Radiation Myelopathy o Fusiform cord expansion with irregular, focal rind of enhancement; demyelination in lateral, dorsal tracts o Demyelination in lateral, dorsal tracts o One month to years following fractionated radiotherapy

;:!. ., OJ

3 CD

<>C

OJ

-<

SELECTED REFERENCES 1.

2.

Jinkins JR et al: MR of parenchymal spinal cord signal change as a sign of active advancement in clinically progressive posttraumatic syringomyelia. AJNR Am J Neuroradiol. 19(1):177-82, 1998 Quencer RM et al: Acute traumatic central cord syndrome: MRI-pathological correlations. Neuroradiology. 34(2):85-94, 1992

Multiple Sclerosis, Spinal Cord

II Sagittal T2WI MR shows T2 hyperintense diiataUon of the central spinal cord, extending from the medulla (syringobulbia) ~ to the UlOracic spine l:JlI. Chiari 1 malformation is not identified.

=

Sagittal T2WI MR shows multiple hyperintense iniiamooulfary lesions with (oc:aJ cord enlargement. White matter & gray maller involvemenl is very common.

7 45

CORD

lESION,

12 HYPERINTENSE,

Multiple Sclerosis, Spinal Cord Q)

c: '0.

en

Myelitis, Idiopathic

area.

Infarction, (Left) Sagittal T2WI MR shows focal T2 hyperintensity within the conus ~ which shows slight expansion. This is spinal cord infarction

after

minor trauma may be due to fibrocartilaginous embolism. Classically, the T2 hyperinlensily involves the anterior horn cells. (Right) Axial T2* eRE MR shows central gray matter hyperintensity

=.

(Left) Sagittal T2WI MR shows diffuse intramedullary hyperinlensily in a case of meningitis complicated by

=

spinal cord ischemia.

Diffuse

leptomeningeal

enhancement (not shown) extends into the posterior fossa. (Right) Sagittal T2WI MR shows a "flame-shaped" hyperintensity !J:&l in the central cord due to venous hypertension. serpentine

Note multiple

intradural

flow

voids from arterialized venous plexus II] along the

46

Acute Transverse

(Left) Axial T7 C+ MR shows an intramedullary lesion with faint ring enhancement m. Axia/ images are useFul for localizing the lesion in relation to the cord's somatotopy. (Right) Sagittal T2WI MR demonstrates intramedullary hyperintensity 1m extending from lower cervical into upper thoracic cord The signal abnormality involves more than 2 vertebral segments in length & more than 2/3 cross-sectional

II 7

CENTRAL

dorsal cord surface.

Spinal Cord

Infarction,

I

Spinal Cord

CORD LESION, 12 HYPERINTENSE, CENTRAL

Acute Disseminated Encephalomyelitis, Spinal Cord

Viral Myelitis (Left) Axial T2WI MR shows cervicothoracic cord expansion and central T2 hyperintensity Mu/tifocal flame-shaped white matter lesions typically have little mass effect or vasogenic edema. (Right) Sagittal T2WI MR shows fusiform expansion of the lower

=.

cervical

and upper thoracic

cord & long segment of diffuse hyperintensity The long segment of involvement favors direct viral infection or post viral demyelinating disease.

=.

Cavernous Malformation,

Spinal Cord (Left) Sagittal T2WI MR shows a discrete lesion within upper cervical cord at C1level with "popcorn'" heterogeneous signal There is peripheral hemosiderin staining but a lack of edema. (Right) Sagittal T2WI MR shows a large spinal cord astrocytoma encompassing

=.

entire cervical

cord

normal-appearing

=.

No

cord

parenchyma at the level of the tumor and the transition between tumor and normal

cord is apparent.

Central Spinal Cord Syndrome (Left) Sagittal STIR MR shows cord hyperintensity & a focal disc protrusion ~ at C3-4 that severely

=

effaces cord.

There is no

hemorrhage within the cord, just nonspecific

hyperilltensity due to compression & contusion. (Right) Sagittal T2WI MR shows diffuse cord

hyperintensityextending inferiorly

from C4 & fusiform

of lower cervical & thoracic cord. IlislOry of radiation treatment & expansion

marrow changes suggest sequela of radiation.

II 7 47

MYElOPATHY

DIFFERENTIAL DIAGNOSIS

t:

a.

w

Common • Infection/Inflammation o Abscess, Epidural o Abscess, Subdural o Multiple Sclerosis, Spinal Cord • eoplasm and Cyst o Syringomyelia o Astrocytoma, Spinal Cord o Ependymoma, Cellular, Spinal Cord o Hemangioblastoma, Spinal Cord • Trauma o Central Spinal Cord Syndrome o Contusion-Hematoma, Spinal Cord o Hematoma, Epidural-Subdural o Hematoma, Subdural o Syrinx, Post-Traumatic • Degenerative o Degenerative Disc Disease o Stenosis, Acquired Spinal, Cervical o Kyphosis o Spondylolisthesis o OPLL o Ossification Ligamentum Flavum • Intervertebral Disc Herniation o Intervertebral Disc Herniation, Cervical o Intervertebral Disc Herniation, Thoracic o Intervertebral Disc Herniation, Traumatic Less Common • Congenital o Mucopolysaccharidoses o Stenosis, Congenital Spinal o Scoliosis and Kyphosis, Congenital • Infection/Inflammation o ADEM, Spinal Cord o Viral Myelitis • Neoplasm and Cyst o Osteochondroma o Pathologic Vertebral Fracture o Arachnoid Cyst • Vascular o Infarction, Spinal Cord o Type I DAVF o Type IV AVF

II 7 48

Rare but Important • Congenital o Spondyloepiphyseal Dysplasia o Dermoid and Epidermoid Tumors o Osteogenesis lmperfecta • Trauma

Spinal Cord Herniation • Neoplasm and Cyst o Neurenteric Cyst o Metastases, Spinal Cord • Vascular o Cavernous Malformation, Spinal Cord o Type II AVM o Type III AVM • Infection/Inflammation o Abscess/Myelitis, Spinal Cord o Acute Transverse Myelitis, Idiopathic o Secondary Acute Transverse Myelitis o Vitamin B12 Deficiency, Spinal Cord o

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Myriad etiologies requires evaluation of pertinent clinical and laboratory information to narrow differential list Helpful Clues for Common Diagnoses • Infection/Inflammation o Epidural and subdural abscess => rim-enhancing extramedullary pus ± cord signal or compression • Neoplasm and Cyst o Syringomyelia => expanded spinal cord + central dilated, beaded, or sacculated cystic cavity o eoplastic syrinx => look for nodularity or enhancement • TraUlna o Central spinal cord syndrome => arms> legs + bladder dysfunction, variable sensory loss, high T2 cord signal • Degenerative o OPLL, OLF => look for ligamentous ossification with narrowing of central spinal canal • Intervertebral Disc Herniation o Use conventional diagnostic criteria Helpful Clues for Less Common Diagnoses • Congenital o Mucopolysaccharidoses => ± dens hypoplasia, CVJ stenosis, thickened dura at foramen magnum, platyspondyly, anterior beaking, thoracolumbar gibbus deformity o Congenital spinal stenosis => reduced AP canal diameter secondary to short, squat pedicles and laterally directed laminae • Infection/Inflammation

MYELOPATHY ADEM, spinal cord => multi focal lesions (MS mimic) with minimal mass effect, vasogenic edema o Viral myelitis => swollen, edematous cord with segmental contiguous T2 signal abnormality • Neoplasm and Cyst o Osteochondroma => sessile or pedunculated osseous "cauliflower" lesion, marrow contiguous with parent vertebra o Arachnoid cyst => nonenhancing extramedullary loculated CSF intensity collection displacing cord or nerve roots • Vascular o Spinal cord infarction => central T2 hyperintensity more common than wedge-shaped injury in anterior 2/3 spinal cord o

Helpful Clues for Rare Diagnoses • Congenital o Dermoid and epidermoid tumors => CSF isodense/isointense lumbosacral or cauda equina mass o Osteogenesis imperfecta => severe osteopenia & multiple fractures • Trauma o Spinal cord herniation => herniation of spinal cord through defect in dura of ventral canal with expansion of dorsal subarachnoid space • Neoplasm and Cyst

Abscess, Epidural

Sagittal TI C+ MR in a patient with meningitis shows progression to parameningeaf inflammation and epidural abscess

=.

Neurenteric cyst => intraspinal cyst lined by enteric mucosa + vertebral segmentation abnormalities o Spinal cord metastasis => focal, enhancing cord lesion(s) + extensive edema • Vascular o Cavernous malformation => locules of blood with fluid-fluid levels surrounded by T2 hypointense rim o Type II AVM => intramedullary glomus type AVM (similar to brain AVM), nidus may extend to dorsal subpial surface o Type III AVM => juvenile-type AVM (intramedullary, extramedullary), nidus may have extramedullary and extraspinal extension • Infection/Inflammation o Spinal cord abscess/myelitis => ring-enhancing mass within cord, appropriate clinical history of inflamma tion/ infection o Acute idiopathic transverse myelitis => central cord lesion extent> 2 vertebral segments + eccentric enhancement o Secondary acute transverse myelitis => T2 hyperintense lesion with mild cord expansion, minimal to no enhancement o Vitamin BI2 deficiency => mild spinal cord enlargement, abnormal T2 hyperintensity within dorsal columns ± lateral columns o

Abscess, Subdural

Sagittal TI C+ FS MR demonstrates a large low signal fluid collection with peripheral enhancement located ventral to cord.

=

II 7 49

MYElOPATHY

Multiple Sclerosis, Spinal Cord Q)

r:: Cl. l/l

(Left) Sagittal T2WI MR shows multiple areas of abnormal

T2 prolongation

in

the brainstem and spinal cord in a patient presenting with myelopathy and known MS. (Right) Sagittal T2WI MR demonstrates a large h%cord syrinx with extra-axial

CSF collection

at

the posterior C '-C2 level in a treated patient with Chiar; 2 malformation

and congenital

craniovertebral

anomalies.

Astrocytoma,

Spinal Cord

(Left) Sagittal T1 C+ MR depicts a very large spinal cord astrocytoma encompassing the entire cervical

spinal cord. No

intrinsic enhancement

is

demonstrated. (Right) Sagittal T2WI MR reveals a typical cellular ependymoma with central cord expansion and mixed signal intensity characterized by intrinsic hypointense intramedullary blood products.

Hemangioblastoma, (Left) Sagittal T1 C+ MR shows a large intramedullary hemangioblaslOma

associated

with

syrinx within the

upper thoracic

spinal cord

and a smaller hemangioblastoma at the foramen of Magendie. (Right) Sagittal T2WI MR in a child following trauma presenting clinically with SCfWORA reveals diffuse long segment intramedullary high signa! intensity. Cervical radiographs

II 7 50

were normal.

Spinal Cord

Central Spinal Cord Syndrome

CJl

MYElOPATHY

't:l

:l

CD

Hematoma,

Epidural-Subdural (Left) Sagittal T2' eRE MR demonstrates post-traumatic cervical epidural hemorrhage and intramedullary spinal cord hemorrhage, leading to

cord compression secondary to post-traumatic disc herniation (Right) SagiLtal T2WI MR confirms a large low signal intensity spontaneous epidural hematoma =:I, producing spinal cord compression.

=.

Hematoma, Subdural

Syrinx, Post-Traumatic (Left) Sagittal TI WI MR

shows a large linear, lobulated T I hyperintense blood collection that extends throughout the cervical and upper

thoracic

spine and

that crosses the skull base along the clivus. (Right) Sagittal T2WI MR demonstrates a focal

post-traumatic

syrinx

= in a

patient with delayed worsening of quadriplegia (ascending leve/) following skiing spinal cord injury.

Stenosis, Acquired Spinal, Cervical

OPLL (Left) Sagittal T2WI MR reveals severe multilevel degenerative spondylosis producing spinal cord compression characterized by abnormal il1lramedullary T2 prolongation. (Right) Sagittal T2WI MR demonstrates multilevel hypointense

ossification

within the posterior longitudinal ligament producing vel1lral spinal cord compression with abnormal T2 prolongation and cord deformation.

II 7 51

MYELOPATHY

Intervertebral CIl

c:

'0.. l/l

Disc Herniation,

Cervical

Intervertebral

Disc Herniation,

(Left) Sagittal T2WI MR shows central disc extrusion effacing the thecal sac causing cord compression. Note abnormal T2 hyperintensily (contusion/myelomalacia) within spinal cord at C3-4. (Right) Sagillal T2WI MR

reveals severa/large

disc

extrusions that compress the ventra/thoracic spinal cord at multiple levels.

Intervertebral Disc Herniation, Traumatic

Mucopolysaccharidoses

(Left) Sagillal T2WI MR shows sequelae of cervical hyperfJexion injury with traumatic herniation

cervical

disc

and ligamentous

injury with herniated C6-7 disc disruption of anterior longitudinalligamcnl @ posterior longitudinal ligament and interspinous ligaments p:jJ. (Right) Sagillal T2WI MR (Morquio, MPS IV) shows odontoid hypoplasia and thick pannus =:I producing

a

=-

cervical canal stenosis and cord compression craniovertebraf

EJ

at the

junction.

ADEM, Spinal Cord (Left) Sagillal T2WI MR shows a variant appearance of congenital cervical spinal stenosis that results from short pedicles in conjunction with congenital vertebral anomalies, producing spinal cord compression =:I and abnormal cord T2 hyperintensity. (Right) Sagillal T2WI MR demonstrates several T2 hyperintense intramedullary lesions within the cervical spinal cord in a patient with correlative clinical history.

II 7 52

Thoracic

MYElOPATHY

Viral Myelitis

Osteochondroma (Left) Sagittal T7 C+ MR demonstrates patchy

heterogeneous

spina! cord

enhancement in a patient with proven viral myelitis (Varicella-Zoster). (Right) Coronal T2WI FS MR reveals a heterogeneous extradural mass originating

from the

right posterior spinal osseous elements that laterally

compresses the thoracic spinal cord.

Infarction,

Spinal Cord (Left) Sagittal T2WI MR demonstrates abnormal expansion

and T2

hyperintensity of the cervical cord extending from C3 to C7. (Right) Sagittal T2WI MR depicts classic central cord T2 hyperintensity sparing the cord periphery. Note multiple

serpentine

intradural flow voids along the dorsal cord surface

representing

the arterialized

venous plexus.

(Left) Sagittal T2WI MR shows multiple

abnormal

flow voids involving dorsal subarachnoid space 81 and extending into dorsal cord surface. Tocal mixed signal intensity is due to high flow aneurysm. (Right) Sagittal T2WI MR confirms characteristic vertebral

=

anomalies

with severe

cranioverlebral

junction

central canal stenosis producing spinal cord

compression.

II 7 53

INDEX A Abscess brain cyst with nodule, 1(5):29, 30 multiple enhancing lesions, 1(5):2, 4 ring-enhancing lesion, solitary, 1(5):6, 8 cerebellar mass, 1(7):22, 25 cystic-appearing posterior fossa lesion, 1(7):35, 38 effaced sulci, focal, 1(4):17,19 epidural mass, 11(5):2,4. See also Epidural abscess medulla lesion, 1(7):11, 13 midbrain lesion, 1(6):100 paraspinal. See Paraspinal abscess parenchymal lesions multiple hypodense, 1(5):60, 62 T1 hypointense, T2 hyperintense, 1(5):91, 93 periventricular, 1(3):58, 60 pituitary, 1(8):25 presacral, 11(1):22,23 prevertebral, II(1):14 pyogenic, 1(7):6 restricted diffusion, 1(5):98, 100 ring-enhancing lesions, multiple, 1(5):12, 13-14 solitary cystic mass, 1(5):17, 19 spinal cord. See Spinal cord abscess subdural, 11(1):30,11(7):48,49 Accelerated degeneration chronic back pain/radiculopathy, postoperative, 11(1):36,39-40 intervertebral disc end plate irregularity, II(4):6, 8 post-traumatic, 11(1):2,4 vertebral body, 11(3):24-25,26 Accessory sutures, 1(1):2 Achondroplasia bony trauma, 1l(1):6, 8 C1-C2 instability, II(2):12 cervical abnormality, chronic post-traumatic, 1l(1):2 craniovertebral junction abnormalities, II(2):4 kyphosis, II(1):12, 13 macrocephaly, 1(1):33, 37 pedicle abnormality, II(3):36 platyspondyly, diffuse, 11(1):16, 17 vertebral anomalies, congenital, 11(3):2 vertebral body dysmorphic, 11(3):10

flattened, II(3):8 fracture, II(3):29 scalloping or widened canal, II(3):18, 19 vertebral endplate contour abnormality, 1l(4):10, 11

Acidopathies, organic, 1(6):80 Acromegaly, 1(1):9, II(3):18 Acute necrotizing encephalopathy of childhood, 1(6):93 Acute transverse myelitis idiopathic acute upper extremity pain or weakness, II(1):43, 47 intramedullary lesions, no enhancement, 1l(7):18, 19 intramedullary lesions, T2 hyperintense, T1 isointense, II(7):30, 32 intramedullary mass, II(7):2 myelopathy, II(7):49 pediatric back pain, II(1):57 subarachnoid space narrowing, II(6):6 T2 hyperintense cord lesions, central, II(7):44, 46 intramedullary lesions, diffuse/ill-defined enhancement, II(7):20, 21 secondary acute upper extremity pain or weakness, II(1):43 intramedullary lesions, T2 hyperintense, Tl isointense, II(7):30, 32 myelopathy, 11(7):49 pediatric back pain, II(1):57, 59 ADEM (acute disseminating encephalomyelitis) basal ganglia, 1(6):70, 81 cerebellar mass, 1(7):22, 25 corpus callosum holes, 1(6):52, 53 lesion without mass effect, 1(6):54 splenium lesion, 1(6):59, 61 cranial nerve enhancement, 1(4):47 hypothalamus lesion, 1(8):49 intramedullary lesions, diffuse/ill-defined enhancement, II(7):20, 22 medulla lesion, 1(7):10, 12 midbrain lesion, 1(6):100, 102 multiple brain hyperintensities (T2/FLAIR), 1(5):70, 71 multiple enhancing lesions, 1(5):2, 4

INDEX ><

QJ

"'C C

II

parenchymal lesions multiple hypodense, 1(5):61, 63 solitary hypodense, 1(5):57, 59 T1 hypointense, T2 hyperintense, 1(5):90, 92 periventricular enhancing lesions, 1(3):58, 60 periventricular T2/FLAIR lesions, 1(3):72, 74 pontine lesion, 1(7):6, 8 "pulvinar sign" (mimic), 1(6):96, 97 ring-enhancing lesions, multiple, 1(5):12, 14 spinal cord acute upper extremity pain or weakness, II(I):43, 47 intramedullary lesions, no enhancement, II(7):18, 19 intramedullary lesions, solid enhancement, II(7):14, 16 intramedullary lesions, T2 hyperintense, Tl isointense, II(7):31, 33 intramedullary lesions, Tl hypointense, II(7):28, 29 intramedullary mass, II(7):2 multiple intramedullary lesions, II(7):12, 13 myelopathy, II(7):49, 52 subarachnoid space narrowing, II(6):6 T2 hyperintense cord lesions, central, II(7):44-45, 47 thalamic lesions bithalamic, 1(6):92, 94 unilateral, 1(6):90, 91 tumefactive, corpus callosum mass, 1(6):56 white matter lesions confluent, 1(6):35, 38 solitary, 1(6):30, 32 Adrenoleukodystrophy, X-linked confluent white matter lesions, 1(6):34, 38 corpus callosum lesion without mass effect, 1(6):54, 55 corpus callosum splenium lesion, 1(6):59, 61 multiple parenchymal calcifications, 1(5):41 periventricular T2/FLAIR lesions, 1(3):73 Aging, brain. See Brain, normal aging Aicardi-Goutieres syndrome interhemispheric fissure cysts, 1(4):21 microcephaly, 1(1):39, 43 periventricular calcifications, 1(3):67, 71 AIDS-related opportunistic infections. See Opportunistic infections, AIDS Alcoholic encephalopathy cerebellar atrophy, 1(7):18, 20 chronic, enlarged sulci, generalized, 1(4):8, 10 corpus callosum splenium lesion, 1(6):58, 61 large ventricles, 1(3):44, 46 thin corpus callosum, 1(6):41, 44 Alexander disease cerebral aqueduct/periaqueductallesion, 1(3):29, 31 confluent white matter lesions, 1(6):35

ependymal/subependymallesions, 1(3):9, 11 foramen of Monro mass, 1(3):19, 21 macrocephaly, 1(1):33, 37 periventricular enhancing lesions, 1(3):58, 61 thick septum pellucidum, 1(3):16, 17 Alzheimer dementia asymmetric cerebral hemispheres, 1(6):2, 4 enlarged sulci, generalized, 1(4):8, 9 large ventricles, 1(3):45 thin cortex, 1(6):14-15, 18 Amyotrophic lateral sclerosis, 1(6):101, II(7):38, 39 Anasarca, scalp, 1(1):4 Anemia, 1(1):9. See also Sickle cell disease Aneurysm. See also Bone cyst, aneurysmal; Pseudoaneurysm aortic, II(I):52, II(5):8, 9 blood blister-like, 1(9):3, 5 CPA-lAC mass, 1(4):24, 26 dissecting, 1(4):60, 1(9):6, 7 fusiform. See Fusiform aneurysm giant serpentine, 1(9):6 saccular. See Saccular aneurysm thrombosed, 1(5):7, 10 vertebral artery, II(3):16 Angiolipoma epidural mass, II(5):3, 7 extradural lesions, solid enhancement, II(5):17, 19

Tl hyperintense extradural lesion, II(5):30, 31 Angiomatosis, cystic, II(3):39. See also Meningioangiomatosis Angiosarcoma, II(3):39 Ankylosing spondylitis cauda equina syndrome, II(6):36 focal vertebral body sclerosis, II(3):42, 43 intervertebral disc end plate irregularity, II(4):7, 9 vertebral end plate signal abnormality, II(4):16,

17 Anterior horns, coarctation, 1(3):2-3, 5 Anterior radiculopathy syndrome, II(6):9, 11, 15 Anticoagulation complications, 1(5):51, 54 Aortic aneurysm, II(I):52, II(5):8, 9 Apophyseal ring fracture, II(I):8, II(3):28 Aqueductal stenosis macrocephaly, 1(1):32, 34 midbrain lesion, 1(6):100, 102 suprasellar cystic mass, 1(8):36, 37 thin skull, generalized, 1(1):14 Arachnoid cyst cauda equina syndrome, II(6):36 cisterna magna mass, 1(4):38, 40 CPA-lAC, 1(4):24, 26, 28, 29 epidural mass, II(5):3, 5 extra-axial fluid collection, CSF-like, 1(4):50, 51 extra-axial mass, 1(4):52, 76, 77 extradural lesions, II(5):14, 33

INDEX interhemispheric fissure cysts, 1(4):20,22 intradural/extramedullary lesions no enhancement, 11(6):12, 13 ring/peripheral enhancement, 11(6):22,23 Tl hypo intense, 11(6):28,29 intrasellar mass, cystic, 1(8):22, 23 macrocephaly, 1(1):32, 34 midline cyst, infratentorial, 1(7):14, 15 myelopathy, 11(7):49 pedicle abnormality, 11(3):36,37 pineal region mass, 1(8):2, 4 posterior fossa lesion, cystic-appearing, 1(7):34,

35 prepontine cistern mass, 1(4):33, 37 quadrigeminal cistern mass, 1(8):8, 9 suprasellar mass cystic, 1(8):36, 38 general, 1(8):24, 26 pediatric, 1(8):30-31, 33 Tl hypointense, 1(8):58 thin skull, localized, 1(1):16 vertebral body scalloping or widened canal, 11(3):18, 19 vestibular schwannoma with, 1(4):29, 31 Arachnoid granulations calvarium, 1(1):2 dural sinuses, 1(4):77, 79, 1(10):2, 3-4 lucent skull lesions, multiple, 1(1):22,24 Arachnoiditis cauda equina enhancement, diffuse, 11(6):3 intradural/extramedullary lesions, T1 hypointense, 11(6):29,31 lumbar chronic back pain/radiculopathy, postoperative, 11(1):37, 41 intradural/extramedullary lesions, 11(6):12, 23, 25 leptomeningeal enhancement, 11(6):9 lower extremity pain, 11(1):49,51 subarachnoid space narrowing, 11(6):6 Arachnoiditis ossificans chronic back pain/radiculopathy, postoperative, 11(1):37,41

intradural/extramedullary lesions ring/peripheral enhancement, 11(6):23,25 Tl hypointense, 11(6):29 Tl hypointense, T2 hypointense, 11(6):32,33 Arterial dissection arterial shape/configuration abnormalities, 1(9):3,5 carotid arteries, 11(2):4,9, 11 hyperattenuating artery, 1(9):8, 9 nonaneurysmal, fusiform arterial enlargement, 1(9):6,7 vertebral artery, 11(2):2 Arteries, 1(9):2-11 fusiform arterial enlargement, 1(9):6-7

hyperattenuating, 1(9):8-9 hyperdensity, physiologic, 1(9):8 infarction, 11(7):20,23. See also Cerebral infarction ischemia, bithalamic lesions, 1(6):92, 93 normal, extra-axial flow voids, 1(4):60 shape/configuration abnormalities, 1(9):2-5 vascular calcifications, 1(9):10-11 Arteriolosclerosis cranial nerve enhancement, 1(4):47 parenchymal lesions, 1(5):90,91 periventricular T2/FLAIR lesions, 1(3):72, 73 pontine lesion, 1(7):6, 7 white matter lesions confluent, 1(6):34, 35 solitary, 1(6):30, 32 Arteriovenous fistula carotid-cavernous bilateral cavernous sinus lesions, 1(10):18, 20 unilateral cavernous sinus mass, 1(10):14-15, 16

conus abnormality, 11(7):7,9 dural. See Dural arteriovenous fistula epidural, 11(5):40 extradural, 11(5):32 type IV, 11(6):36,11(7):48,53 Arteriovenous malformation. See also Developmental venous anomaly brain cyst with nodule, 1(5):29, 31 cerebellar mass, 1(7):23, 26 conus abnormality, 11(7):7,9 cortical veins, enlarged, 1(10):8, 9 deep veins, enlarged, 1(10):10, 12 ependymal enhancement, 1(3):41, 43 epilepsy, 1(5):118, 120 extra-axial flow voids, 1(4):60, 61 intradural/extramedullary lesions Tl hypointense, 11(6):28,31 Tl hypointense, T2 hypointense, 11(6):32,33 intramedullary lesions, T1 hyperintense, 11(7):35,37 intramedullary mass, 11(7):3,4 medulla lesion, 1(7):10, 12 micro-AV malformations, multiple, 1(5):82, 85 parenchymal calcification, solitary, 1(5):34-35, 37 parenchymal lesion, solitary hyperdense, 1(5):45, 47 pontine lesion, 1(7):6 sellar/juxtasellar calcification, 1(8):15, 17 thrombosed, 1(5):7, 10 type 1,11(6):18 type II intradural lesion, serpentine, 11(6):18 intramedullary lesion, solid enhancement, 11(7):15, 17 intramedullary lesions, T1 hypointense, 11(7):28,29 iii

INDEX )(

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iv

intramedullary lesions, Tl hypointense, T2 hypointense, II(7):26, 27 myelopathy, II(7):49 type III, II(6):18, II(7):49 type IV,II(6):18, 19 vascular calcifications, 1(9):10 venous extradural lesions, solid enhancement, II(5):16 lumbar soft tissue mass, pediatric, II(5):42-43, 45 vein of Galen. See Vein of Galen malformation vermis mass, 1(7):28-29, 30 Arthritis. See also Juvenile idiopathic arthritis; Rheumatoid arthritis osteoarthritis, II(2):5, 6 septic facet joint, II(3):32, 33 Arthropathies. See also Spondyloarthropathy crystalline, II(I):2 facet. See Facet arthropathy hemodialysis, II(I):2 neurogenic. See Neurogenic arthropathy Astroblastoma "bubbly-appearing" intraventricular mass, 1(3):37 in children over 1 year, 1(5):113 focal cortical mass, 1(6):21 Astrocytoma. See also Xanthoastrocytoma, pleomorphic anaplastic in children over 1 year, 1(5):113 corpus callosum mass, 1(6):56, 57 midbrain lesion, [(6):100 in newborn/infant, 1(5):106, 107 parenchymal lesions, 1(5):56, 58, 90 posterior fossa, adult, 1(7):41, 43 posterior fossa, pediatric, 1(7):45, 48 thalamic lesion, unilateral, 1(6):90, 91 white matter lesion, solitary, 1(6):31, 33 basal ganglia lesions, bilateral, 1(6):80, 82 desmoplastic infantile, 1(5):107, 109 diffuse, low grade. See Astrocytoma - diffuse, low grade diffuse fibrillary, 1(6):100, 1(7):10, 12 foramen of Monro mass, 1(3):18, 20 giant cell, sub ependymal. See Giant cell astrocytoma, subependymal intramedullary lesions, II(7):20-21, 23 lateral ventricle mass, 1(3):13 oligoastrocytoma, 1(6):31 pilocytic. See Astrocytoma - pilocytic pilomyxoid. See Astrocytoma - pilomyxoid spinal cord. See Spinal cord astrocytoma thick septum pellucidum, 1(3):16-17 vertebral body scalloping or widened canal, I1(3): 18

Astrocytoma - diffuse, low grade bithalamic lesions, 1(6):92, 94 cerebral aqueduct/periaqueductal lesion, 1(3):28, 30 in children over 1 year, 1(5):112 cortical hyperintensity Tl/FLAIR, 1(6):24, 26 effaced sulci, focal, 1(4):16, 18 focal cortical mass, 1(6):20, 22 foramen magnum mass, 1(4):42, 44 hypothalamus lesion, 1(8):48, 49 parenchymal calcification, solitary, 1(5):34, 37 parenchymal lesions, 1(5):56-57, 58,90 pineal gland mass, 1(8):6 posterior fossa, adult, 1(7):41, 43 sellar/juxtasellar calcification, 1(8):14-15 suprasellar mass enhancing, 1(8):42 general, 1(8):25, 28 Tl isointense, 1(8):54, 55 tecta I plate lesion, 1(6):98 thalamic lesions, unilateral, 1(6):90, 91 thin skull, localized, 1(1):16 Astrocytoma - pilocytic cerebellar mass, 1(7):22, 24 in children over 1 year, 1(5):112, 113 cyst with nodule, 1(5):28, 29 focal cortical mass, 1(6):21, 23 fourth ventricle mass, 1(3):32, 34 hypothalamus lesion, 1(8):48, 49 infratentorial midline cyst, 1(7):14, 16 parenchymal calcification, solitary, 1(5):34, 37 parenchymal lesions, solitary hypodense, 1(5):57, 59 pontine lesion, 1(7):6, 9 posterior fossa adult neoplasm, 1(7):41 cystic-appearing lesion, 1(7):34, 36 pediatric neoplasm, 1(7):44, 45 ring-enhancing lesion, solitary, 1(5):7, 11 sellar/ juxtasellar calcification, 1(8):14 solitary cystic mass, 1(5):17, 18 suprasellar mass calcified, 1(8):40, 41 cystic, 1(8):37 enhancing, 1(8):42 general, 1(8):24, 26 pediatric, 1(8):30, 31 Tl hypointense, 1(8):58, 59 Tl isointense, 1(8):54, 55 vermis mass, 1(7):28, 29 Astrocytoma - pilomyxoid in children over 1 year, 1(5):112, 114 hypothalamus lesion, 1(8):49, 51 sellar/juxtasellar calcification, 1(8):15, 16 suprasellar mass cystic, 1(8):37, 39 general, 1(8):25, 28

INDEX hyperdense, 1(8):52 pediatric, 1(8):31, 34 T1 hyperintense, 1(8):56 T1 hypointense, 1(8):58 Astrocytosis, reactive multiple brain hyperintensities (T2/FLAIR), 1(5):64, 66 solitary white matter lesion, 1(6):30, 32 Ataxia, hereditary, 1(7):19, 21 Atherosclerosis, intracranial arterial shape/configuration abnormalities, 1(9):2,3 calcified suprasellar mass, 1(8):40 hyperattenuating artery, 1(9):8, 9 multiple brain hyperintensities (T2/FLAIR), 1(5):64,66 sellar/juxtasellar calcification, 1(8):14, 15 vascular calcifications, 1(9):10 Atlanto-occipital dislocation, 11(2):2,4 Atrial diverticulum, medial, 1(4):21, 23 Auditory canal, internal, 1(4):24-27 Axonal injury, diffuse. See Diffuse axonal injury (DAI)

B Baastrup sign, 11(3):12, 13 Back pain adult, 11(1):52-55 pediatric, 11(1):56-59 postoperative radiculopathy acute, 11(1):30-35 chronic, 11(1):36-41 Bacterial infections intramedullary lesions, 11(7):20,21 multiple hypointense foci on T2, 1(5):80, 81 Balloon cell dysplasia, 1(5):118, 122, 1(6):8, 10 Band heterotopia, 1(5):119, 122 Basal cell carcinoma, 1(1):4, 5 Basal cell nevus syndrome, 1(2):2, 3 Basal ganglia bilateral lesions, 1(6):80-83 calcification, 1(6):62-65 T1 hyperintense, 1(6):66-69 T2 hyperintense, 1(6):70-73 Basilar invagination (mimic), 1(7):32, 33 Basivertebral vein, 11(3):56 Behfi:etdisease, 1(3):29 Bell palsy, 1(4):47, 49 Benign macrocrania of infancy, 1(4):9, 11 Bithalamic lesions, 1(6):92-95 Blake pouch cyst, 1(4):2, 3 Blake pouch remnant, 1(3):3, 5 Blood-brain barrier leakage, 1(4):64-65, 67 Blue rubber bleb nevus syndrome, 1(10):11 Bone abnormalities, congenital, 11(2):5 Bone cement, 11(3):56

Bone cyst, aneurysmal abnormal extradural marrow signal, 11(5):27,29 craniovertebral junction abnormalities, 11(2):4 enlarged vertebral body, soap bubble expansion, 11(3):38,41 enlarged vertebral body/posterior element, 11(3):13, 15 epidural mass, 11(5):2,6 extradural lesion, Tl hypointense, 11(5):32 kyphoscoliosis, child, 11(1):14 lytic skull lesion, solitary, 1(1):18 neural foramen, enlarged, 11(3):16 pedicle abnormality, 11(3):36 sacral mass, adult, 11(1):19 Bone dysplasia, sclerosing, 1(1):9 Bone graft complications acute back pain/radiculopathy, 11(1):31,35 chronic back pain/radiculopathy, 11(1):37,40-41 Bone island extradural lesions, no enhancement, 11(5):14 focal Tl hypointense signal, vertebral body, 11(3):56 focal vertebral body sclerosis, 11(3):42 Bone marrow extradural abnormal marrow signal, 11(5):26-29 normal marrow signal, 11(5):22-25 fatty, 11(3):48,49, 50, 51 vertebral hemorrhage, 11(3):50,51 hyperplastic, 11(3):52,53 post-irradiation, 11(3):48,11(5):14 Bone morphogenetic protein, 11(4):7,9 Bone tumors, primary adult back pain, 11(1):52 epidural mass, 11(5):2 extradural lesions, 11(5):33,37 lower extremity pain, 11(1):48 Bones, worm ian, 1(1):2 Brachial plexus neuritis, idiopathic, 11(1):43,47 Brachial plexus traction injury acute back pain/radiculopathy, 11(1):31,35 acute upper extremity pain or weakness, 11(1):42,45 Brain immature, thin corpus callosum, 1(6):40, 41 injury. See also Cerebral contusion remote, parenchymal calcifications, 1(5):41, 42 thin corpus callosum, 1(6):41, 44 neoplasms. See also specific histologic types in children over 1 year, 1(5):112-117 epilepsy, 1(5):118 in newborn/infant, 1(5):106-111 primary, 1(5):90-91 normal aging basal ganglia calcification, 1(6):62, 63 v

INDEX ><

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VI

cerebellar atrophy, 1(7):18, 19 confluent white matter lesions, 1(6):34, 35 enlarged perivascular spaces, 1(6):74, 75 enlarged sulci, generalized, 1(4):8, 9 extra-axial fluid collection, CSF-like, 1(4):50 large ventricles, 1(3):44, 45 multiple brain hyperintensities (T2/FLAIR), 1(5):64, 65 multiple parenchymal calcifications, 1(5):40 periventricular T2/FLAIRlesions, 1(3):72, 73 thin cortex, 1(6):14, 15 normal variants asymmetric cerebral hemispheres, 1(6):2, 3 corpus callosum, abnormal shape or configuration, 1(6):46, 47 enlarged perivascular spaces, 1(6):74 thin corpus callosum, 1(6):40 physiologic calcification basal ganglia, Tl hyperintense, 1(6):66, 67 parenchymal, 1(5):35, 38, 40 Brain death effaced sulci, generalized, 1(4):12 hyperdense CSF (mimic), 1(4):72, 73 low cerebellar tonsils, 1(7):32, 33 small ventricles, 1(3):48 Brain parenchyma, 1(5):2-123. See also Infratentorial brain parenchyma; Parenchymal metastases; Supratentorial brain parenchyma calcifications multiple, 1(5):40-43 physiologic, 1(5):35, 38, 40 solitary, 1(5):34-39 CSF-like lesions, 1(5):22-27 cyst with nodule, 1(5):28-31 cystic mass, solitary, 1(5):16-21 epilepsy, 1(5):118-123 fat-like lesions, 1(5):32-33 hyperdense lesions multiple, 1(5):50-55 solitary, 1(5):44-49 hypodense lesions multiple, 1(5):60-63 solitary, 1(5):56-59 multiple brain hyperintensities (T2/FLAIR) common, 1(5):64-69 less common, 1(5):70-75 rare but important, 1(5):76-79 multiple enhancing lesions, 1(5):2-5 multiple hypointense foci on GRE/SWI, 1(5):82-85 multiple hypointense foci on T2, 1(5):80-81 restricted diffusion, 1(5):98-101 ring-enhancing lesions multiple, 1(5):12-15 solitary, 1(5):6-11 Tl hyperintense lesions, 1(5):102-105 Tl hypointense, T2 hyperintense lesions, 1(5):90-93

Tl/T2 hyperintense lesions, 1(5):86-89 Tl/T2 isointense lesions, 1(5):94-97 tumors, pediatric in children over 1 year, 1(5):112-117 in newborn/infant, 1(5):106-111 "Brain rock," 1(5):35, 38 Brainstem large, 1(7):2 medulla lesion, 1(7):10 midbrain lesion, 1(6):100 pontine lesion, 1(7):6, 8 small, 1(7):4-5 Brainstem glioma craniovertebral junction soft tissue abnormalities, II(2):9 large brainstem, 1(7):2 medulla lesion, adult, 1(7):10, 12 pediatric in children over 1 year, 1(5):112, 114 craniovertebral junction abnormalities, II(2):4 exophytic, prepontine cistern mass, 1(4):32, 35 fourth ventricle mass, 1(3):32, 34 medulla lesion, 1(7):10 in newborn/infant, 1(5):107, 111 posterior fossa neoplasm, 1(7):44, 46-47 tecta I plate lesion, 1(6):98, 99 Brucellosis, II(4):7 Budd-Chiari syndrome. See Chiari 2 (Budd-Chiari syndrome) Burr holes lytic skull lesion, solitary, 1(1):18, 19 multiple lucent skull lesions, 1(1):22, 24 Burst fractures cervical acute upper extremity pain or weakness, II(I):42, 44 C2, cranio-cervical junction acute injury, II(2):2 C2, craniovertebral junction abnormalities, II(2):5 C2, posterior element fracture, II(3):34 post-traumatic bony abnormality, II(I):4, 5 posterior element fracture, II(3):34 vertebral body fracture, II(3):28 flattened vertebral body, II(3):6, 7 lumbar bony trauma, II(I):8 cauda equina syndrome, II(6):36, 37 kyphosis, 1I(1):12, 13 posterior element fracture, II(3):34, 35 vertebral body fracture, II(3):28 mild, vertebral body, II(3):28 thoracic bony trauma, 1I(1):6 thoracolumbar posterior element fracture, II(3):34 vertebral body fracture, 1I(3):28, 29

INDEX c CADASIL confluent white matter lesions, 1(6):35, 37 enlarged perivascular spaces, 1(6):74 multiple brain hyperintensities (T2/FLAIR), 1(5):76, 77 multiple hypodense parenchymal lesions, 1(5):61 periventricular T2/FLAIR lesions, 1(3):73, 75 Calcific tendinitis, longus coli CI-C2 instability, 11(2):12 craniovertebral junction abnormalities, 11(2):4 soft tissue calcification, paraspinal, 11(5):20,21 Calcinosis, tumoral, 11(5):3,5, 32 Calcium pyrophosphate deposition disease (CPPD) CI-C2 instability, 11(2):12,13 chronic post-traumatic cervical abnormality, 11(1):2 craniovertebral junction abnormalities, 11(2):4,7 odontoid deformity, 11(2):14 Callosal dysgenesis abnormal shape or configuration of corpus callosum, 1(6):46, 48 extra-axial mass, CSF-Iike, 1(4):52, 53 interhemispheric fissure cysts, 1(4):20, 22 thin corpus callosum, 1(6):40, 43 Callosectomy/callosotomy, 1(6):40, 43, 46, 48 Calvarium fracture, 1(1):27 Canavan disease, 1(1):33, 37, 1(6):34, 38 Carbon monoxide poisoning basal ganglia calcification, 1(6):63 Tl hyperintense, 1(6):66, 68 T2 hyperintense, 1(6):70, 72 confluent white matter lesions, 1(6):35 globus paIIidus lesions, 1(6):86, 88 multiple brain hyperintensities (T2/FLAIR), 1(5):71, 75 Carcinoma basal cell, 1(1):4, 5 choroid plexus. See Choroid plexus carcinoma lung, 11(3):38,39 nasopharyngeal craniovertebral junction abnormalities, 11(2):4 craniovertebral junction soft tissue abnormalities, 11(2):8-9, 10 unilateral cavernous sinus mass, 1(10):14, 16 renal cell, 11(3):38,40 squamous cell, 1(1):4 thyroid, 11(3):38,39 Carcinomatosis, meningeal, 1(4):54, 55-56 Carotid artery dissection/pseudoaneurysm, 11(2):4,9, 11 internal, paramedian ("kissing"), 1(8):12, 13, 20, 21

Carotid-cavernous fistula bilateral cavernous sinus lesions, 1(10):18, 20 traumatic, unilateral cavernous sinus mass 1(10):14-15, 16 ' Cauda equina enhancement, diffuse, 11(6):2-5 Cauda equina syndrome, 11(6):36-37 Caudal regression syndrome conus abnormality, 11(7):6,9 flattened vertebral body, multiple, 11(3):8 kyphoscoliosis, child, 11(1):14 sacral deformity, 11(1):27,29 vertebral anomalies, congenital, 11(3):2 Cavernous malformation acquired, 1(5):70, 72 basal ganglia calcification (mimic), 1(6):63 "bubbly-appearing" intraventricular mass, 1(3):36-37, 39 cerebellar mass, 1(7):23, 25-26 congenital, 1(5):70, 72 focal cortical mass, 1(6):21, 23 foramen of Monro mass, 1(3):19 hypothalamus lesion, 1(8):49 intraventricular calcifications, 1(3):63, 65 large brainstem, 1(7):2, 3 lateral ventricle mass, 1(3):13 medulla lesion, 1(7):10, 12 midbrain lesion, 1(6):100, 102 multiple hypointense foci on GRE/SWI, 1(5):82, 84-85 parenchymal calcifications, 1(5):34, 36, 40 parenchymal lesions multiple hyperdense, 1(5):50, 53 solitary hyperdense, 1(5):44, 47 Tl hyperintense, 1(5):102, 105 Tl/T2 hyperintense, 1(5):86, 88 pontine lesion, 1(7):6 sellar/juxtasellar calcification, 1(8):15, 17 spinal cord. See Cavernous malformation spinal cord suprasellar mass general, 1(8):25, 29 Tl hyperintense, 1(8):56, 57 tecta I plate lesion, 1(6):98, 99 vascular calcifications, 1(9):10, 11 vermis mass, 1(7):29, 30 Cavernous malformation - spinal cord conus abnormality, 11(7):6-7 intramedullary lesions multiple, 11(7):12, 13 no enhancement, 11(7):18, 19 solid enhancement, 11(7):14,16 Tl hyperintense, 11(7):34,36 Tl hypo intense, 11(7):28,29 Tl hypointense, T2 hypo intense, 11(7):26,27 intramedullary mass, 11(7):3,5 myelopathy, 11(7):49 T2 hyperintense cord lesions, central, 11(7):45, 47 vii

INDEX )(

CI.I "'C

C

Cavernous sinuses bilateral lesions, 1(10):18-21 thrombosis, 1(10):15,17,18-19,20 unilateral mass, 1(10):14-17 Cavum septi pellucidi cistern and subarachnoid space normal variants, 1(4):2 foramen of Monro mass, 1(3):18, 19 thick septum pellucidum, 1(3):16 ventricles, normal variant, 1(3):2, 4 Cavum velum interpositum cistern and subarachnoid space normal variants, 1(4):2,3 pineal region mass, 1(8):2, 3 quadrigeminal cistern mass, 1(8):8 Cellular ependymoma, spinal cord intramedullary lesions multiple, II(7):12, 13 no enhancement, II(7):18 ring/peripheral enhancement, II(7):24, 25 solid enhancement, II(7):14, 15 Tl hyperintense, II(7):34, 35-36 T2 hyperintense, Tl isointense, II(7):30, 32 Tl hypointense, II(7):28 myelopathy, II(7):48, 50 subarachnoid space narrowing, II(6):6 Central spinal cord syndrome myelopathy, II(7):48, 50 T2 hyperintense cord lesions, central, II(7):45, 47 Cephalhematoma, calcified sclerotic skull lesions, solitary, 1(1):26-27, 29 thick skull, localized, 1(1):12, 13 Cephalocele atretic, 1(1):4, 1(4):21, 23 extra-axial fluid collection, CSF-like, 1(4):50 lytic skull lesion, solitary, 1(1):19 Cerebellar tonsils, low, 1(7):32-33 Cerebellitis cerebellar atrophy, 1(7):19, 21 cerebellar mass, 1(7):22-23, 25 vermis mass, 1(7):29, 30 Cerebellopontine angle (CPA) cystic mass, 1(4):28-31 mass in adults, 1(4):24-27 Cerebellum atrophy, 1(7):18-21 hemorrhage, remote, 1(7):23, 27 hereditary atrophy, 1(7):19, 21 hypoplasia, 1(1):38, 42 mass, 1(7):22-27 Cerebral amyloid disease (angiopathy) confluent white matter lesions, 1(6):34, 36 multiple brain hyperintensities (T2/FLAIR), 1(5):70, 71 multiple hypointense foci on GRE/SWI, 1(5):82,

84 VIII

parertchymallesions multiple hyperdense, 1(5):50 , 52 solitary hyperdense, 1(5):44, 46 Tl hyperintense, 1(5):102, 104 Tl hypointense, T2 hyperintense, 1(5):91, 92 Tl/T2 hyperintense, 1(5):86, 88 perivascular space enhancing lesions, 1(6):76, 78 Cerebral aqueduct lesions, 1(3):28-31 stenosis, 1(3):28, 29 Cerebral atrophy, 1(3):44, II(7):1O Cerebral contusion asymmetric cerebral hemispheres, 1(6):2, 4 cortical hyperintensity Tl/FLAIR, 1(6):24,25 midbrain lesion, 1(6):100, 101 multiple brain hyperintensities (T2/FLAIR), 1(5):65 parenchymal lesions multiple hyperdense, 1(5):50, 51 multiple hypodense, 1(5):60, 61 solitary hyperdense, 1(5):44, 45 solitary hypodense, 1(5):56, 57 Tl hypointense, T2 hyperintense, 1(5):90 Cerebral cortex. See also Cortical veins contusion, 1(4):16, 17 dysplasia focal cortical mass, 1(6):21, 23 microcephaly, 1(1):38, 41 laminar necrosis, 1(5):103 thick, 1(6):8-13 thin, 1(6):14-19 Cerebral edema diffuse (mimic), 1(4):72, 73 traumatic asymmetric cerebral hemispheres, 1(6):2, 4 effaced sulci, 1(4):12, 13 multiple brain hyperintensities (T2/FLAIR), 1(5):65 small ventricles, 1(3):48 Cerebral hemispheres, asymmetric, 1(6):2-7 Cerebral hyperperfusion syndrome cortical enhancement, 1(6):28, 29 effaced sulci, generalized, 1(4):13, 15 Cerebral infarction. See also Cerebral ischemiainfarction, acute chronic asymmetric cerebral hemispheres, 1(6):2, 4 corpus callosum, abnormal shape or configuration, 1(6):47, 49-50 irregular large ventricles, 1(3):54, 56 multiple brain hyperintensities (T2/FLAIR), 1(5):65, 68 parenchymal lesions, 1(5):56, 58, 102 small brainstem, 1(7):4 thin cortex, 1(6):14, 17 hypotensive basal ganglia, 1(6):66, 68, 70

INDEX confluent white matter lesions, 1(6):34, 36 cortical enhancement, 1(6):28, 29 cortical hyperintensity Tl/FLAIR, 1(6):24, 26 effaced sulci, generalized, 1(4):12 multiple brain hyperintensities (T2/FLAIR), 1(5):65, 68 putamen lesions, 1(6):84 parenchymal lesions, multiple hypodense, 1(5):60, 61 subacute cortical enhancement, 1(6):28 multiple brain hyperintensities (T2/FLAIR), 1(5):64-65, 68 parenchymal lesions, multiple hyperdense, 1(5):50,53 parenchymal lesions, solitary hypodense, 1(5):56,58 parenchymal lesions, Tl/T2 hyperintense, 1(5):87, 89 parenchymal lesions, Tl/T2 isointense, 1(5):95,97 pial enhancement, 1(2):16, 18 ring-enhancing lesions, 1(5):6, 9, 13, 15 Cerebral ischemia-infarction, acute asymmetric cerebral hemispheres, 1(6):2, 4 cerebellar mass, 1(7):22, 23 cortical hyperintensity Tl/FLAIR, 1(6):24, 25 effaced sulci, focal, 1(4):16, 17 FLAIRhyperintense CSF,1(4):65, 67 focal cortical mass, 1(6):20, 21 hyperattenuating artery, 1(9):8, 9 large brainstem, 1(7):2, 3 midbrain lesion, 1(6):100, 101 parenchymal lesions, 1(5):56, 57, 94, 95 pontine lesion, 1(7):6, 7 restricted diffusion, 1(5):98, 99 Cerebral palsy, 11(1):10 Cerebral venous thrombosis, deep effaced sulci, generalized, 1(4):13, 15 enlarged deep veins, 1(10):10, 12 ependymal enhancement, 1(3):40-41 unilateral thalamic lesion, 1(6):90, 9] Cerebritis cortical enhancement, 1(6):28, 29 cortical hyperintensity Tl/FLAIR, 1(6):25 focal cortical mass, 1(6):20, 22 multiple brain hyperintensities (T2/FLAIR), 1(5):70, 73 parenchymal lesions, 1(5):57, 59, 90, 93 Cerebrospinal fluid (CSF). See also Flow artifacts, CSF FLAIRhyperintense, 1(4):64-67 gadolinium from blood-brain barrier leakage, 1(4):64-65,67 hyperdense, 1(4):72-73 obstructed spaces, 1(1):32, 33-34 pulsation

extra-axial flow voids, 1(4):60, 61 intraventricular artifact, 1(3):2, 4 third ventricle mass, body/posterior, 1(3):26 shunts and complications asymmetric lateral ventricles, 1(3):50-51, 53 irregular large ventricles, 1(3):54, 55 lytic skull lesion, solitary, 1(1):18 small ventricles, 1(3):48 Tl hyperintense, 1(4):62-63 Cervical spine accelerated degeneration, 11(1):2,4 back pain/radiculopathy, postoperative, 11(1):30,

-

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Q.

I'D

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32

bony fusion, 11(3):4-5 CI-C2 instability, 11(2):12-13 chronic post-traumatic abnormality, 11(1):2-3 fracture with nerve compression, 11(1):42,44-45 incomplete fusion, posterior element CI-C2 instability mimic, 11(2):12 cranio-cervical junction acute injury, 11(2):2 post-traumatic bony abnormality, 11(1):4 lower subaxial fractures, 11(1):4 stenosis, acquired, 11(7):48,51 Chance fracture flattened vertebral body, solitary, 11(3):6 lumbar bony trauma, 11(1):8,9 kyphosis, 11(1):12, 13 posterior element fracture, 11(3):34,35 thoracic bony trauma, II(I):6 kyphoscoliosis, child, II(I):14 kyphosis, 11(1):12 posterior element fracture, 11(3):34 vertebral body fracture, 11(3):28,30 Charcot arthropathy. See Neurogenic arthropathy Chemotherapy. See Radiation and chemotherapy Chest wall abnormalities, II(I):10 Chiari 1 (Chiari-Frommel syndrome) cisterna magna mass, 1(4):38, 39 craniovertebral junction abnormalities, 11(2):4, 6,9

foramen magnum mass, 1(4):42, 44 low cerebellar tonsils, 1(7):32-33 Chiari 2 (Budd-Chiari syndrome) cisterna magna mass, 1(4):38, 40 craniovertebral junction abnormalities, 11(2):4, 6, 9 foramen magnum mass, 1(4):42, 44 irregular large ventricles, 1(3):54, 56 lacunar skull, 1(1):23, 25 prepontine cistern mass, 1(4):32, 34 tectal plate lesion, 1(6):98, 99 Chondroid tumor, 1(8):40 Chondrosarcoma adult back pain, II(I):52 craniovertebral junction abnormalities, 1l(Z):4, 9,11 IX

INDEX enlarged vertebral body, soap bubble expansion, 11(3):38,41 enlarged vertebral body/posterior element, 11(3):13, 15 epidural mass, 11(5):2,6 extradural lesions, 11(5):32,37 extradural marrow signal, abnormal, 11(5):26,28 falx lesions, 1(2):12 lower extremity pain, 11(1):48 sacral mass, adult, 11(1):19 sacrococcygeal mass, pediatric, 11(1):23 skull base foramen magnum masses, 1(4):43 prepontine cistern mass, 1(4):33, 36 sellar/juxtasellar calcification, 1(8):15 spondylolisthesis, 11(3):20 Chordoma cavernous sinus mass, unilateral, 1(10):15, 17 clivus. See Clivus, chordoma craniovertebral junction soft tissue abnormalities, 11(2):9, 11 enlarged vertebral body, soap bubble expansion, 11(3):38,41 enlarged vertebral body/posterior element, 11(3):13, 15 epidural mass, 11(5):2 extradural lesions, 11(5):32,37 extradural marrow signal, abnormal, 11(5):27,28 posterior fossa lesion, cystic-appearing, 1(7):35 sacral deformity, 11(1):27,29 sacral mass, adult, 11(1):18, 20 sacrococcygeal mass, pediatric, 11(1):22,24 sellar/juxtasellar calcification, 1(8):15, 17 Choriomeningitis, lymphocytic, 1(5):41, 42 Choroid plexus enlargement, 1(3):6 lesions, 1(3):6-7 lipoma, 1(3):6 physiologic calcification, 1(3):62, 63 villous hypertrophy, 1(1):32, 35 xanthogranuloma, 1(5):32 Choroid plexus carcinoma, 1(3):6 asymmetric lateral ventricles, 1(3):51 "bubbly-appearing" intraventricular mass, 1(3):37 in children over 1 year, 1(5):113, 117 ependymal/subependymallesions, 1(3):8, 11 intraventricular calcifications, 1(3):63 lateral ventricle mass, 1(3):13 in newborn/infant, 1(5):107, 110 posterior fossa neoplasm, pediatric, 1(7):45, 49 Choroid plexus cysts, 1(3):6 asymmetric lateral ventricles, 1(3):50, 53 "bubbly-appearing" intraventricular mass, 1(3):36,37 foramen of Monro mass, 1(3):19 intraventricular calcifications, 1(3):62, 63 x

lateral ventricle mass, 1(3):12, 13 Choroid plexus papilloma asymmetric lateral ventricles, 1(3):51, 53 "bubbly-appearing" intraventricular mass, 1(3):37,39 in children over 1 year, 1(5):113, 115 CPA mass, 1(4):25, 27 foramen of Monro mass, 1(3):19 fourth ventricle mass, 1(3):32, 34 intraventricular calcifications, 1(3):62, 64 large ventricles, 1(3):45, 47 lateral ventricle mass, 1(3):12, 14 lesion vs., 1(3):6, 7 in newborn/infant, 1(5):106, 109 posterior fossa neoplasm, pediatric, 1(7):45 posterior fossa neoplasms, adult, 1(7):41, 42 third ventricle mass, body/posterior, 1(3):26, 27 third ventricle mass, general, 1(3):22, 25 Chronic inflammatory demyelinating polyneuropathy (CIDP) cauda equina enhancement, diffuse, 11(6):3,5 cauda equina syndrome, 1l(6):36 cranial nerve enhancement, 1(4):47, 49 intradural/extramedullary lesions, 11(6):12, 15, 17

leptomeningeal enhancement, 11(6):9,11 Cisterna magna mass, 1(4):38-41. See also Mega cisterna magna Clay shoveler's fracture, 11(3):34 Cleidocranial dysplasia, 1(1):14, 15 Clinoids, aerated, 1(1):2, 3 Clivus chordoma bilateral cavernous sinus lesions, 1(10):19, 20 craniovertebral junction abnormalities, 1l(2):4 foramen magnum masses, 1(4):43 prepontine cistern mass, 1(4):33, 36 sellar/juxtasellar calcification, 1(8):15, 17 nasopharyngeal tumor invading, 1(4):33, 37 neoplasms, prepontine cistern mass, 1(4):33 CMV. See Cytomegalovirus (CMV) infections Coagulopathies, 1(5):83 Coats-Plus syndrome, 1(3):67, 71 Coccidiomycosis, 1l(4):7, 8 Cockayne syndrome, 1(1):39, 43 Collateral veins, occlusion, 11(6):18, 19 Colloid cyst foramen of Monro mass, 1(3):18, 20 third ventricle mass, general, 1(3):22, 24 Compression fractures anterior lumbar, 11(1):8,12, 11(3):28, 29 thoracic, 11(1):6, 12, 13, 11(3):28 vertebral end plate contour abnormality, 11(4):10, 11 benign, adult back pain, 1l(1):53, 54

INDEX focal vertebral body sclerosis, 11(3):42,43 lateral lumbar, 11(1):8,14, 11(3):28 scoliosis, 11(1):10 thoracic, 11(1):6,14, II(3):28 vertebral endplate contour abnormality, 11(4):10 wedge, II(4):16, 17 Compressive myopathy, chronic, 11(7):10 Connatal cysts CSF-like parenchymal lesions, 1(5):23, 25 ventricles, normal variant, 1(3):3, 5 Connective tissue disorders kyphoscoliosis, child, II(I):14 scoliosis, II(I):lO Contrast complications effaced sulci, generalized, 1(4):13 leakage, sulcal/cisternal enhancement, 1(4):55, 57 Tl hyperintense CSF,1(4):62 Contrast material, 1(4):72, 73 Contusion-hematoma, spinal cord intramedullary lesions no enhancement, II(7):18, 19 Tl hyperintense, 11(7):34,35 T2 hyperintense, Tl isointense, 11(7):30 Tl hypointense, II(7):28 Tl hypointense, T2 hypointense, 11(7):26 intramedullary mass, 11(7):3,4 myelopathy, II(7):48, 51 T2 hyperintense cord lesions dorsal, 11(7):40,42 ventral, 11(7):38 Conus abnormality, 11(7):6-9 Convolutional markings, 1(1):2, 22, 24 Copper deficiency, II(7):40 Corpus callosum abnormal shape or configuration, 1(6):46-51 dysgenesis. See Callosal dysgenesis holes in, 1(6):52-53 lesion without mass effect, 1(6):54-55 masses, 1(6):56-57 normal variant, 1(6):46, 47 splenium lesion, 1(6):58-61 thin, 1(6):40-45 Cortical contusion, 1(4):16,17 Cortical dysplasia focal cortical mass, 1(6):21, 23 effaced sulci, focal, 1(4):17 ependymal/subependymallesions, 1(3):8, 10 epilepsy, 1(5):118, 122 Taylor type, 1(5):118, 122, 1(6):8, 10 microcephaly, 1(1):38,41 Cortical laminar necrosis, 1(5):103 Cortical veins enlarged, 1(10):8-9

normal, 1(10):8 thrombosis enlarged cortical veins, 1(10):8, 9 multiple hyperdense parenchymal lesions, 1(5):50,53 solitary hyperdense parenchymal lesions, 1(5):44, 46 solitary hypodense parenchymal lesion, 1(5):57, 59 solitary white matter lesion, 1(6):31, 33 Corticobasal degeneration, 1(4):9, 11 CPPO. See Calcium pyrophosphate deposition disease (CPPO) Cranial nerves, enhancement, 1(4):46-49 Cranio-cervical junction, acute injury, 11(2):2-3 Craniopharyngioma in children over 1 year, 1(5):112, 115 extra-axial mass(es), hypodense, 1(4):77, 78 fat-like lesions, 1(5):32, 33 hypothalamus lesion, 1(8):48, 50 intrasellar lesion, 1(8):20, 21 intra sellar mass, cystic, 1(8):22, 23 intraventricular calcifications, 1(3):63, 65 prepontine cistern mass, 1(4):33, 37 sellar/juxtasellar calcification, 1(8):14, 16 suprasellar mass calcified, 1(8):40 cystic, 1(8):36, 38 enhancing, 1(8):42, 43 general, 1(8):24, 26 hyperdense, 1(8):52, 53 pediatric, 1(8):30, 32 Tl hyperintense, 1(8):56 Tl hypointense, 1(8):58, 59 third ventricle mass, 1(3):23, 25 Craniostenosis, 1(1):27, 29 Craniovertebral junction, II(2):2-15 abnormalities, general, 11(2):4-7 acute injury, 1I(2):2-3 CI-C2 instability, 11(2):12-13 cranio-cervical junction acute injury, 1I(2):2, 3 odontoid deformity, II(2):14-15 post-traumatic cervical abnormality, chronic, 11(1):2 soft tissue abnormalities, 11(2):8-11 variants CI-C2 instability, II(2):12, 13 congenital vertebral anomalies, 11(3):2 craniovertebral junction abnormalities, 1I(2):4, 6 odontoid deformity, 11(2):14, 15 Creutzfeldt-jakob disease basal ganglia bilateral lesions, 1(6):81, 83 T2 hyperintense, 1(6):71, 73 bithalamic lesions, 1(6):93, 95 cortical hyperintensity Tl/FLAIR, 1(6):25

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XI

INDEX >< cu c

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enlarged sulci, generalized, 1(4):9, 11 large ventricles, 1(3):45 "pulvinar sign," 1(6):96-97 putamen lesions, 1(6):84, 85 restricted diffusion, 1(5):99, 101 Cryptococcosis bilateral basal ganglia lesions, 1(6):81 CSF-like parenchymal lesions, 1(5):23, 26 enlarged perivascular spaces, 1(6):74, 75 intramedullary lesions, Tl hyperintense, 11(7):35, 37

Crystalline arthropathies, 11(1):2 CSF. See Cerebrospinal fluid (CSF) Cushing disease congenital vertebral anomalies, 11(3):2 flattened vertebral body, multiple, 11(3):8 platyspondyly, diffuse, 11(1):16 thoracic bony trauma, 11(1):6 vertebral body fracture, 11(3):28 vertebral end plate contour abnormality, 11(4):10 Cyanide poisoning, 1(6):86, 88 Cysticercosis conus abnormality, 11(7):7 intradural/extramedullary lesions multiple, 11(6):20, 21 ring/peripheral enhancement, 11(6):22, 25 T2 hyperintense, T1 isointense, 11(6):34, 35 T1 hypointense, 11(6):29 intramedullary lesions multiple, 11(7):12, 13 ring/peripheral enhancement, 11(7):24, 25 T1 hypointense, T2 hypointense, 11(7):26, 27 intramedullary mass, 11(7):3 Cysts arachnoid. See Arachnoid cyst bone. See Bone cyst, aneurysmal choroid plexus. See Choroid plexus cysts colloid foramen of Monro mass, 1(3):18, 20 third ventricle mass, general, 1(3):22, 24 connatal CSF-like parenchymal lesions, 1(5):23, 25 ventricles, normal variant, 1(3):3, 5 dermoid. See Dermoid cyst discal, 11(4):3, 5 enteric, 11(1):23 ependymal. See Ependymal cyst epidermal inclusion, 1(1):4 epidermoid. See Epidermoid cyst germinolytic CSF-like parenchymal lesions, 1(5):23, 27 ventricles, normal variant, 1(3):3, 5 interhemispheric fissure, 1(4):20-23 leptomeningeal extra-axial mass, CSF-like, 1(4):52 lytic skull lesion, solitary, 1(1):19, 21 neurenteric. See Neurenteric cyst xii

neuroglial CSF-like parenchymal lesions, 1(5):23, 26 cystic-appearing posterior fossa lesion, 1(7):34, 38

solitary cystic mass, 1(5):17, 20-21 perineural root sleeve. See Perineural root sleeve cysts pineal. See Pineal cyst porencephalic. See Porencephalic cyst Rathke cleft. See Rathke cleft cyst sebaceous, 1(1):4, 5 synovial. See Synovial cyst tumor-associated, 1(4):21, 23 Cytomegalovirus (CMV) infections congenital asymmetric cerebral hemispheres, 1(6):2, 5 basal ganglia calcification, 1(6):62, 64 irregular large ventricles, 1(3):55, 57 periventricular calcifications, 1(3):66, 67 polyradiculopathy, 11(6):3, 4 radiculopathy, 11(6):15, 17

o DAI. See Diffuse axonal injury (DAI) Dandy-Walker continuum cisterna magna mass, 1(4):38, 40 cystic-appearing posterior fossa lesion, 1(7):34,

36 extra-axial fluid collection, CSF-Iike, 1(4):50, 51 infratentorial midline cyst, 1(7):14, 16 macrocephaly, 1(1):32, 35 Degeneration, accelerated. See Accelerated degeneration Degenerative disc disease chronic back pain/radiculopathy, postoperative, 11(1):36, 39

endplate irregularity, 11(4):6, 7 kyphosis, 11(1):12 myelopathy, 11(7):48 spondylolisthesis, 11(3):20, 22 T2 hyperintense disc, 11(4):14-15 T1 hypointense disc, 11(4):12 Dementia Alzheimer. See Alzheimer dementia frontotemporal. See Frontotemporal dementia multi-infarct. See Multi-infarct dementia vascular, 1(4):8, 10 with Lewy bodies, 1(4):8 Demyelinating diseases brain stem, large, 1(7):2, 3 conus abnormality, 11(7):6, 8 deep veins, enlarged, 1(10):11, 13 hypothalamus lesion, 1(8):49 intramedullary mass, 11(7):2, 3 medulla lesion, 1(7):10, 12 midbrain lesion, 1(6):100, 102

INDEX parenchymal lesions, T1 hypointense, T2 hyperintense, 1(5):90 pontine lesion, 1(7):6, 8 subarachnoid space narrowing, 11(6):6 tumefactive, 1(5):6, 9, 1(7):22 Dermal sinus, dorsal, 11(5):14 Dermatomyositis, 11(5):20 Dermoid cyst cavernous sinus mass, unilateral, 1(10):15, 17 cisterna magna mass, 1(4):39,41 cystic mass, solitary, 1(5):17, 20 extra-axial masses, hypodense, 1(4):77, 79 foramen magnum mass, 1(4):43, 45 fourth ventricle mass, 1(3):33 interhemispheric fissure cysts, 1(4):21, 23 lytic skull lesion, solitary, 1(1):18-19, 21 Meckel cave lesion, 1(10):23, 25 midline cyst, infratentorial, 1(7): 15, 17 parenchyma, fat-like lesions, 1(5):32, 33 pineal region mass, 1(8):3, 5 posterior fossa lesion, cystic-appearing, 1(7):34,

37 quadrigeminal cistern mass, 1(8):8 ruptured fat in sulci/cisterns/ventricles, 1(4):58, 59 FLAIR hyperintense CSF, 1(4):65 Tl hyperintense CSF, 1(4):62, 63 Tl hyperintense parenchymal lesions, 1(5):102 scalp, 1(1):4, 5, 16 sellar/juxtasellar calcification, 1(8): 15, 17 suprasellar mass calcified, 1(8):40, 41 cystic, 1(8):36, 38 general, 1(8):25, 27 pediatric, 1(8):31 Tl hyperintense, 1(8):56, 57 vermis mass, 1(7):29, 31 Dermoid tumor intradural/extramedullary lesions, Il(6):12, 26, 27 myelopathy, Il(7):49 sacrococcygeal mass, pediatric, 11(1):23, 24 spinal cord, intramedullary lesions, 11(7):34, 37 vertebral body scalloping or widened canal, 11(3):18 Developmental venous anomaly. See also Arteriovenous malformation enlarged cortical veins, 1(10):8 enlarged deep veins, 1(10):10, 11 ependymal enhancement, 1(3):40, 41 ependymal/subependymal lesions, 1(3):8, 10 extra-axial flow voids, 1(4):60, 61 parenchymal lesions solitary hyperdense, 1(5):44-45, 47 Tl/T2 isointense, 1(5):94, 96

Devices and complications. See also Metal artifact hyperattenuating artery, 1(9):8, 9 multiple hypointense foci on GRE/SWI, 1(5):83 Diabetes mellitus cranial nerve enhancement, 1(4):47 vascular calcifications, 1(9):10, 11 Diastematomyelia congenital vertebral anomalies, 11(3):2, 3 conus abnormality, 11(7):6 extradural lesions, Il(5):14 intramedullary lesions, 11(7):26, 27 kyphoscoliosis, child, 11(1):14 vertebral body fracture, 11(3):28 vertebral body scalloping or widened canal, Il(3):18, 19 Diffuse axonal injury (DAI) cerebral aqueduct/periaqueductallesion, 1(3):28,

30 corpus callosum abnormal shape or configuration, 1(6):47, 50 holes, 1(6):52 lesion without mass effect, 1(6):54 splenium lesion, 1(6):58, 59 large ventricles, 1(3):45 midbrain lesion, 1(6):100, 101 multiple brain hyperintensities (T2/FLAIR), 1(5):65, 68 multiple hypointense foci on GRE/SWI, 1(5):82,

84 parenchymal lesions multiple hyperdense, 1(5):50, 51 multiple hypodense, 1(5):60, 62 Tl hypo intense, T2 hyperintense, 1(5):90 periventricular T2/FLAIR lesions, 1(3):72, 74 restricted diffusion, 1(5):98, 100 Dilantin, chronic use cerebellar atrophy, 1(7):18, 20 thick skull, generalized, 1(1):8, 10 Disc herniation. See Intervertebral disc herniation Discal cyst, 11(4):3, 5 Discitis, chronic, Il(3):44, 45 Discogenic sclerosis, Il(3):44 DISH. See Skeletal hyperostosis, diffuse idiopathic (DISH) Dissection, arterial. See Arterial dissection Distraction fracture, low thoracic, 11(1):6, Il(3):28,

30 DNET (dysembryoplastic neuroepithelial tumor) in children over 1 year, 1(5):112, 115 cortical hyperintensity Tl/FLAIR, 1(6):25, 27 cyst with nodule, 1(5):29, 31 effaced sulci, focal, 1(4):16, 18 epilepsy, 1(5):119, 123 focal cortical mass, 1(6):21, 23 solitary cystic mass, 1(5):17, 19 solitary parenchymal calcification, 1(5):35, 39 thick cortex, 1(6):9, 12 thin skull, localized, 1(1):16, 17 XIII

INDEX ><

ClJ "'C C

-

xiv

Dolichoectasia arterial shape/configuration abnormalities, 1(9):2, 3 fusiform arterial enlargement, 1(9):6 vertebrobasilar foramen magnum mass, 1(4):42, 43 prepontine cistern mass, 1(4):32, 33 Down syndrome, 11(2):14, 15 Drug abuse basal ganglia bilateral lesions, 1(6):80, 83 T2 hyperintense, 1(6):70, 72 epilepsy, 1(5):118 globus pallidus lesions, 1(6):86, 88 large ventricles, 1(3):45, 47 parenchymal lesions, solitary hyperdense, 1(5):45, 48 periventricular T2/FLAIR lesions, 1(3):73, 75 white matter lesions, confluent, 1(6):35 Drug toxicity corpus callosum splenium lesion, 1(6):58 midbrain lesion, 1(6):101 multiple brain hyperintensities (T2/FLAIR), 1(5):71, 75 Dural arteriovenous fistula brain intradural lesion, serpentine, 11(6):18, 19 intramedullary lesions, 11(7):20,22 cerebellar mass, 1(7):23, 26 dural sinus lesion, 1(10):2, 6 enlarged cortical veins, 1(10):8, 9 enlarged deep veins, 1(10):10-11, 12 ependymal enhancement, 1(3):41, 43 extra-axial flow voids, 1(4):60, 61 extra-axial lesions, 1(4):69 extra-axial mass, hyperdense, 1(4):74 falx lesions, 1(2):12, 13 intrasellar lesion, 1(8):20 pial enhancement, 1(2):17 pituitary gland enlargement, 1(8):18 spinal, type 1 intradural/extramedullary lesions, multiple, 11(6):20, 21 intramedullary lesion, solid enhancement, 11(7):15, 17 intramedullary lesions, diffuse/ill-defined enhancement, 11(7):20,22 intramedullary lesions, T2 hyperintense, Tl isointense, 11(7):30-31, 32 myelopathy, 11(7):48, 53 T2 hyperintense cord lesions, central, 11(7):44,46 traumatic, acute upper extremity pain or weakness, 11(1):42,45 vermis mass, 1(7):28, 30 Dural-based masses multiple, 1(2):8-11

solitary, 1(2):4-7 Dural calcifications, 1(2):2-3 falx lesions, 1(2):12 physiologic, 1(2):2, 1(4):68 sellar/juxtasellar calcification, 1(8):14, 15 Dural dysplasia enlarged neural foramen, 11(3):16, 17 pedicle abnormality, 11(3):36 sacral deformity, 11(1):26,27 vertebral body scalloping or widened canal, 11(3):18 Dural sinuses arachnoid granulations, 1(4):77, 79, 1(10):2, 3-4 hyperdensity, 1(10):26-29 hypoplasia-aplasia, 1(10):2, 5 lesions, general, 1(10):2-7 thrombosis chronic, Meckel cave lesion, 1(10):23, 25 dural sinus lesion, 1(10):2, 5 effaced sulci, generalized, 1(4):12-13, 15 enlarged cortical veins, 1(10):8, 9 enlarged deep veins, 1(10):10, 12 extra-axial flow voids, 1(4):60 hyperdense extra-axial mass, 1(4):74 hyperdensity, 1(10):26, 28 solitary hyperdense parenchymal lesions, 1(5):44, 46 venous stenosis dural sinus lesion, 1(10):3, 7 enlarged deep veins, 1(10):11 Dural tail sign, 1(2):20-21 Dural thickening, postoperative, 1(2):14 Dwarfism, primordial, 1(1):14. See also Thanatophoric dwarfism Dyke-Davidoff-Masson syndrome asymmetric cerebral hemispheres, 1(6):2, 5 asymmetric lateral ventricles, 1(3):51 thick skull, localized, 1(1):12, 13 Dysembryoplastic neuroepithelial tumor. See DNET (dysembryoplastic neuroepithelial tumor) Dysembryoplastic neuroepithelioma, 1(4):16, 18 Dysraphism, dorsal, 11(1):26-27, 11(7):7

E Ecchordosis physaliphora posterior fossa neoplasms, adult, 1(7):41, 43 prepontine cistern mass, 1(4):33, 37 Echinococcus abnormal extradural marrow signal, 11(5):27 intradural/extramedullary lesions, 11(6):23,25, 34 Edema, scalp, 1(1):4 Ehlers-Danlos IV, 1(9):6 Ehlers-Danlos syndrome, 11(1):16 Embolism, septic multiple brain hyperintensities (T2/FLAIR), 1(5):71, 73

INDEX multiple hypointense foci on GRE/SWI, 1(5):83 Embolus, calcified plaque, 1(9):10, 11 solitary parenchymal calcification, 1(5):35, 38 Emissary veins, 1(1):2, 22, 23 Empty sella cystic intrasellar mass, 1(8):22 intrasellar lesion, 1(8):20 normal sella variant, 1(8):12, 13 Empyema epidural, 1(4):5, 6 extra-axial CSF-like fluid collection, 1(4):50, 51 effaced sulci, focal, 1(4):17 falx lesions, 1(2):12, 13 hypodense extra-axial masses, 1(4):77, 79 restricted diffusion, 1(5):98, 100 scoliosis, 11(1):10 solitary dural-based mass, 1(2):4 Encephalitis. See also Herpes encephalitis asymmetric cerebral hemispheres, 1(6):3, 5 basal ganglia, 1(6):67, 71, 73 cerebral aqueduct/periaqueductal lesion, 1(3):28-29, 30 corpus callosum splenium lesion, 1(6):58, 60 effaced sulci, generalized, 1(4):12, 14 enlarged deep veins, 1(10):11 enlarged sulci, generalized, 1(4):8 HIV-related, 1(4):9, 10, 1(6):34, 37 Japanese, 1(6):67 large brainstem, 1(7):2 midbrain lesion, 1(6):100 multiple brain hyperintensities (T2/FLAIR), 1(5):70, 73 panencephalitis, subacute sclerosing, 1(5):77, 79, 1(6):35 parenchymal lesions multiple hypodense, 1(5):60, 62 solitary hypodense, 1(5):57 T1 hyperintense, 1(5):103, 105 T1 hypointense, T2 hyperintense, 1(5):90, 93 pontine lesion, brainstem, 1(7):7 Rasmussen, 1(5):77, 79 restricted diffusion, 1(5):99, 100 small ventricles, 1(3):48, 49 thick cortex, 1(6):8, 9 tick-borne, 11(6):2,5 viral bilateral basal ganglia lesions, 1(6):81 bithalamic lesions, 1(6):93 focal cortical mass, 1(6):21 medulla lesion, 1(7):11 West Nile, 1(5):76, 78 white matter lesions confluent, 1(6):35, 37 solitary, 1(6):30-31, 33 Encephalocele, 1(7):34, 36

Encephalomalacia asymmetric lateral ventricles, 1(3):50, 52 cerebellar atrophy, 1(7):18, 19-20 CSF-like parenchymal lesions, 1(5):22,23 large ventricles, 1(3):44 multiple brain hyperintensities (T2/FLAIR), 1(5):64, 66 post-inflammatory, 1(6):2, 4 post-ischemic, 1(5):90, 1(6):2, 3 post-traumatic, 1(5):90, 1(6):2, 4 solitary cystic mass, 1(5):16, 18 thin corpus callosum, 1(6):40, 42 thin cortex, 1(6):14, 18 Encephalomyelitis, acute disseminating. See ADEM (acute disseminating encephalomyelitis) Encephalopathy. See also Leukoencephalopathy; MELAS acute necrotizing, of childhood, 1(6):93 alcoholic. See Alcoholic encephalopathy Hashimoto, 1(5):76, 78 hepatic chronic, enlarged sulci, 1(4):9 globus pallidus lesions, 1(6):86, 88 T1 hyperintense basal ganglia, 1(6):66, 68 hypertensive. See Hypertensive encephalopathy hypoxic-ischemic. See Hypoxic-ischemic encephalopathy (HIE) toxic/metabolic, 1(4):12, 13 Wernicke. See Wernicke encephalopathy Enchondroma, 11(3):39 Endocrine disorders, 1(6):62, 67 Endolymphatic sac anomaly, 1(4):29, 31 Enteric cyst, 11(1):23 Ependymal cyst asymmetric lateral ventricles, 1(3):51, 53 "bubbly-appearing" intraventricular mass, 1(3):37 cystic-appearing posterior fossa lesion, 1(7):35, 38 foramen of Monro mass, 1(3):19, 21 fourth ventricle mass, 1(3):33, 35 lateral ventricle mass, 1(3):12-13, 15 suprasellar cystic mass, 1(8):37, 39 third ventricle mass, body/posterior, 1(3):26 Ependymal enhancement, 1(3):40-43 Ependymal/subependymallesions, 1(3):8-11 Ependymal/subependymal veins (mimic), 1(3):59 Ependymal veins, enlarged, 1(10):10-13 Ependymoma "bubbly-appearing" intraventricular mass, 1(3):36,38 cellular, spinal cord. See Cellular ependymoma, spinal cord in children over 1 year, 1(5):112, 114 cisterna magna mass, 1(4):38, 40 CPA mass, 1(4):25, 27 ependymal/subependymallesions, 1(3):8 xv

INDEX ><

QJ

"'C C

foramen magnum mass, 1(4):42, 44 fourth ventricle mass, 1(3):32, 33 intradural/extramedullary lesions, II(6):34 intraventricular calcifications, 1(3):62, 64 lateral ventricle mass, 1(3):13, 15 myxopapillary. See Myxopapillary ependymoma pedicle abnormality, II(3):36, 37 periventricular enhancing lesions, 1(3):58, 61 posterior fossa neoplasm, pediatric, 1(7):44, 46 solitary parenchymal calcification, 1(5):35, 37-38

spinal cord, II(7):2, 3-4 supratentorial in newborn/infant, 1(5):106, 108 solitary cystic mass, 1(5):17, 21 solitary hyperdense parenchymal lesions, 1(5):45, 47

vertebral body scalloping or widened canal, II(3):18, 19

Epidermal inclusion cyst, 1(1):4 Epidermal nevus syndrome, 1(6):3, 7 Epidermoid cyst cavernous sinus mass, unilateral, 1(10):15, 17 cisterna magna mass, 1(4):39, 41 CPA-lAC, 1(4):24, 26, 28, 29

extra-axial fluid collection,

II(3):18

Epidural abscess back pain/radiculopathy, postoperative, II(1):30, 33 disc contour abnormality, II(4):3, 5 extradural lesions multiple, II(5):12, 13 T2 hyperintense, T1 isointense, II(5):36, 38 T1 hypointense, II(5):32-33, 34 myelopathy, II(7):48, 49 normal extradural marrow signal, II(5):22, 24 paravertebral cauda equina syndrome, II(6):36, 37 craniovertebral junction abnormalities,

CSF-like (mimic),

1(4):50

extra-axial mass CSF-like, 1(4):52, 53 hypodense, 1(4):77, 79 foramen magnum mass, 1(4):43, 45 fourth ventricle mass, 1(3):32, 35 infratentorial midline cyst, 1(7):14-15, 16 interhemispheric fissure cysts, 1(4):21, 23 intrasellar mass, cystic, 1(8):22, 23 intraventricular mass, "bubbly-appearing," 1(3):36, 39

lateral ventricle mass, 1(3):13 lytic skull lesion, solitary, 1(1):18, 20 Meckel cave lesion, 1(10):23, 25 pineal region mass, 1(8):3, 5 posterior fossa lesion, cystic-appearing, 1(7):34, 37 prepontine cistern mass, 1(4):32, 34 quadrigeminal cistern mass, 1(8):8, 9 restricted diffusion, 1(5):98, 100 of scalp, 1(1): 16 solitary cystic mass, 1(5):17, 20 suprasellar mass cystic, 1(8):37, 38 general, 1(8):25, 28 T1 hypointense, 1(8):58, 59 "white," 1(5):32 Epidermoid tumor acquired intradural/extramedullary lesions, no enhancement, II(6):12, 13 XVI

intramedullary lesion, ring/peripheral enhancement, II(7):24, 25 intradural/extramedullary lesions no enhancement, II(6):12 T1 hyperintense, II(6):26, 27 T2 hyperintense, T1 isointense, II(6):34, 35 T1 hypointense, II(6):28, 30 myelopathy, II(7):49 sacrococcygeal mass, pediatric, II(1):23, 24 spinal cord, II(7):34, 37 vertebral body scalloping or widened canal,

II(2):4, 7

lower extremity pain, II(1):49, 51 subarachnoid space narrowing, II(6):6, 7 upper extremity pain or weakness, acute, II(1):43, 46

Epidural Epidural Epidural acute,

fat, normal, II(5):30 gas, II(5):32, 40 hematoma T1 hypointense extradural

lesion,

II(5):32, 34

back pain/radiculopathy,

postoperative,

II(1):30,

34 dural-based masses, 1(2):4, 5, 9, 11 effaced sulci, focal, 1(4):16 epidural mass, brain, 1(4):4, 5 extra-axial lesions, T2 hypointense, 1(4):68 extra-axial masses, 1(4):74, 77, 79 extradural lesions, multiple, II(5):12, 13 lower extremity pain, II(1):49, 51 spontaneous, II(5):22, 24 Epidural mass, spine, II(5):2-7 Epidural-subdural hematoma cauda equina syndrome, II(6):36 disc contour abnormality, II(4):3 extradural lesions no enhancement, II(5):14 T1 hyperintense, II(5):30-31 T2 hyperintense, T1 isointense, II(5):36, 39 myelopathy, II(7):48, 51 normal extradural marrow signal, II(5):22 subarachnoid space narrowing, I1(6):6, 7

INDEX Epilepsy, 1(5):118-123. See also Status epilepticus Erdheim-Chester disease bilateral cavernous sinus lesions, 1(10):19 dural-based masses, multiple, 1(2):8-9, 11 dural tail sign, 1(2):20 falx lesions, 1(2):12 Ewing sarcoma back pain, pediatric, Il(1):57 epidural mass, Il(5):2, 7 extradural lesions solid enhancement, II(5):16, 19 T2 hyperintense, Tl isointense, II(5):37 Tl hypointense, II(5):32 extradural marrow signal, abnormal, II(5):27, 29 kyphoscoliosis, child, Il(1):14 lumbar soft tissue mass, pediatric, Il(5):42, 44 sacral mass, adult, II(1):19, 21 sacrococcygeal mass, pediatric, II(1):23, 24 vertebral body dysmorphic, 1I(3):10 flattened, solitary, 1I(3):6 fracture, II(3):28 Extra-axial flow voids, 1(4):60-61 Extra-axial lesions, T2 hypointense, 1(4):68-71 Extra-axial masses CSF-like, 1(4):52-53 hyperdense, 1(4):74-75 hypodense, 1(4):76-79 Extra-axial spaces and subarachnoid cisterns, 1(4):2-79 cerebellopontine angle (CPA) cystic mass, 1(4):28-31 mass, adult, 1(4):24-27 cerebrospinal fluid FLAIRhyperintense, 1(4):64-67 hyperdense, 1(4):72-73 Tl hyperintense, 1(4):62-63 cisterna magna mass, 1(4):38-41 cranial nerve enhancement, 1(4):46-49 epidural mass, brain, 1(4):4-7 extra-axial flow voids, 1(4):60-61 extra-axial fluid collection, CSF-like, 1(4):50-51 extra-axial lesions, T2 hypointense, 1(4):68-71 extra-axial masses CSF-like, 1(4):52-53 hyperdense, 1(4):74-75 hypodense, 1(4):76-79 fat in sulci/cisterns/ventricles, 1(4):58-59 foramen magnum mass, 1(4):42-45 interhemispheric fissure cysts, 1(4):20-23 normal variants, 1(4):2-3 prepontine cistern mass, 1(4):32-37 sulcal/cisternal enhancement, 1(4):54-57 sulci, effaced focal,I(4):16-19 generalized,I(4):12-15 sulci, enlarged, generalized, 1(4):8-11

Extradural area, spine, II(5):2-45 epidural mass, II(5):2-7 extradural lesions multiple, Il(5):12-13 no enhancement, II(5):14-15 solid enhancement, II(5):16-19 Tl hyperintense, 1I(5):30-31 T2 hyperintense, Tl isointense, II(5):36-39 Tl hypointense, II(5):32-35 T2 hypointense, Tl hypointense, 11(5):40-41 lumbar soft tissue mass, pediatric, II(5):42-45 marrow signal abnormal, II(5):26-29 normal, II(5):22-25 paraspinal mass, ventral/lateral, 11(5):8-9 paraspinal muscle abnormalities, II(5):10-11 soft tissue calcification, paraspinal, II(5):20-21 Extrinsic mass effect, 1(3):50, 51

F Fabry disease, 1(5):102, 1(6):96, 97 Facet lamina fracture, thoracic, 11(1):6,7, 1I(3):34 posterior fracture, lumbar, 11(1):8,II(3):34, 35 tropism, II(3):32 Facet arthropathy adult back pain, II(1):52, 53 cervical bony abnormality, post-traumatic, II(1):4 enlarged vertebral body/posterior element, 1I(3):12, 13 normal extradural marrow signal, 1I(5):22, 24 epidural mass, II(5):2, 3 extradural lesions, multiple, II(5):12 lumbar enlarged vertebral body/posterior element, 11(3):12,13 normal extradural marrow signal, Il(5):22, 24 Fahr disease basal ganglia calcification, 1(6):62, 64 Tl hyperintense, 1(6):67, 69 bithalamic lesions, 1(6):93 globus palIidus lesions, 1(6):87 parenchymal calcifications, multiple, 1(5):41, 43 parenchymal lesions, 1(5):87, 102 Failed back surgery syndrome chronic back pain/radiculopathy, postoperative, II(1):36, 37 kyphosis, 1I(1):12, 13 scoliosis, 1I(1):1O Failure of vertebral formation cervical bony fusion, II(3):4 congenital kyphosis, II(1):10, 12 scoliosis, II(1):10 XVII

INDEX "'C

>< aJ

C

vertebral anomalies, 11(3):2 kyphoscoliosis, child, 11(1):14 vertebral body flattened, solitary, 11(3):6,7 fracture, 11(3):28 Falx lesions, 1(2):12-13 ossified, 1(5):32, 33 Familial tumoral calcinosis, 1(2):2 Femoral neuropathy, 11(1):48 Fetal alcohol syndrome, 1(1):38, 41, 11(1):10 Fibro-osseous lesion, 1(2):4 Fibrodysplasia ossificans progressiva, 11(5):20 Fibrolipoma. See Filum terminale fibrolipoma Fibromatosis, aggressive, 1(1):19 Fibrosarcoma, soft tissue, 11(5):8,10 Fibrothorax, 11(1):10 Fibrous dysplasia bony trabeculae, thickened, 11(3):46,47 lytic skull lesion, solitary, 1(1):18, 21 macrocephaly, 1(1):33, 37 pedicle abnormality, 11(3):36 sclerotic skull lesions, 1(1):26 , 28, 30, 31 scoliosis, 11(1):10 thick skull, 1(1):8, 10, 12, 13 vertebral body diffuse Tl hypointense signal, 11(3):53, 55 enlarged, soap bubble expansion, 11(3):38-39, 41

vertebral body/posterior element, enlarged, 11(3):13 Filum terminale fibrolipoma conus abnormality, 11(7):6,7 intradural/extramedullary lesions, 11(6):12,26 Fissure cysts, interhemispheric, 1(4):20-23 Flow artifacts, CSF foramen of Monro mass, 1(3):18, 19 intradural/extramedullary lesions multiple, 11(6):20 no enhancement, II(6):12 Tl hypointense, II(6):28 Tl hypointense, T2 hypointense, 11(6):32 intradural lesion, serpentine, 11(6):18 intramedullary lesions, T1 hypointense, Il(7):28 prepontine cistern mass, 1(4):32, 33 Flow voids, extra-axial, 1(4):60-61 Fluorosis, 1(1):9, 11(3):44 Foramen magnum mass, 1(4):42-45 Foramen of Monro mass, 1(3):18-21 Foramina, asymmetric, 1(1):2, 3 Foreign bodies, scalp mass, 1(1):4 Fracture-dislocation, Il(1):8 Fracture mimics cranio-cervical junction acute injury, II(2):2 posterior elements, Il(1):4, 8

xviii

vertebral body, 11(1):8,11(3):28 Friedrich ataxia, 1(7):4, II(1):10 Frontometaphyseal dysplasia, 1(1):12 Frontotemporal dementia asymmetric cerebral hemispheres, 1(6):2, 5 enlarged sulci, generalized, 1(4):8, 10 large ventricles, 1(3):45 thin cortex, 1(6):15, 18 Fungal diseases intervertebral disc endplate irregularity, Il(4):7, 8 multiple hypointense foci on GRE/SWl, 1(5):83, 85 multiple hypointense foci on T2, 1(5):80, 81 parenchymal lesions, Tl hyperintense, 1(5):102 prepontine cistern mass, 1(4):33, 36 ring-enhancing lesions, 1(5):7, 11, 13, 15 sulcal/cisternal enhancement, 1(4):55, 57 suprasellar mass, hyperdense, 1(8):52 Fusiform aneurysm atherosclerotic arterial shape/configuration abnormalities, 1(9):2-3,4 fusiform arterial enlargement, 1(9):6, 7 vascular calcifications, 1(9):10, 11 extra-axial flow voids, 1(4):60, 61 hyperattenuating artery, 1(9):8 nonatherosclerotic arterial shape/configuration abnormalities, 1(9):3,4-5 fusiform arterial enlargement, 1(9):6, 7 prepontine cistern mass, 1(4):32, 34 suprasellar mass calcified, 1(8):40, 41 hyperdense, 1(8):52 Fusiform arterial enlargement, 1(9):6-7

G Gadolinium blood-brain barrier leakage, FLAIRhyperintense CSF,1(4):64-65, 67 focal T1 hyperintense signal, vertebral body, II(3):50, 51 Gangliocytoma, dysplastic cerebellar cerebellar mass, 1(7):23, 27 in children over 1 year, 1(5):113 cortical hyperintensity Tl/FLAIR, 1(6):25, 27 posterior fossa adult, 1(7):41,43 pediatric, 1(7):45, 49 thick cortex, 1(6):9, 13 vermis mass, 1(7):29, 31 Ganglioglioma cerebellar mass, 1(7):23, 27 in children over 1 year, 1(5):112, 115 cyst with nodule, 1(5):28, 30

INDEX cystic mass, solitary, 1(5):17, 19 desmoplastic infantile cyst with nodule, 1(5):29 focal cortical mass, 1(6):21, 23 in newborn/infant, 1(5):106-107, 109 solitary cystic mass, 1(5):17, 21 epilepsy, 1(5):119, 123 focal cortical mass, 1(6):21, 23 hypothalamus lesion, 1(8):49 infratentorial midline cyst, 1(7):15, 17 intramedullary lesion, solid enhancement, 11(7):15,17 intramedullary mass, 11(7):3,5 parenchymal calcification, solitary, 1(5):34, 37 parenchymal lesion, solitary hyperdense, 1(5):45, 48 posterior fossa, pediatric, 1(7):44, 47 thick cortex, 1(6):9, 12 thin skull, localized, 1(1):16, 17 vermis mass, 1(7):29, 31 Ganglioma effaced sulci, focal, 1(4):16, 18 ring-enhancing lesion, solitary, 1(5):7, 11 Ganglioneuroma, 11(5):8 Gaucher disease, 11(1):16,17,11(4):7 Germ cell neoplasms cavernous sinus lesions, bilateral, 1(10):19,21 pineal + suprasellar lesions, 1(8):10, 11 pineal gland mass, 1(8):6, 7 Germinal matrix hemorrhage, 1(3):67, 70 Germinolytic cysts CSF-like parenchymal lesions, 1(5):23, 27 ventricles, normal variant, 1(3):3, 5 Germinoma in children over 1 year, 1(5):112, 115 ependymal/subependymallesions, 1(3):8 foramen of Monro mass, 1(3):19, 21 hypothalamus lesion, 1(8):48, 50 parenchymal lesions, solitary hyperdense, 1(5):45, 48 periventricular enhancing lesions, 1(3):58, 60 pineal + suprasellar lesions, 1(8):10 pineal gland mass, 1(8):6, 7 pineal region mass, 1(8):3, 5 suprasellar mass enhancing, 1(8):42, 43 general, 1(8):25,27 hyperdense, 1(8):52, 53 pediatric, 1(8):30, 32 T1 isointense, 1(8):54 thalamic lesion, unilateral, 1(6):90 thick infundibular stalk, 1(8):46 thick septum pellucidum, 1(3):16,17 third ventricle mass body/posterior, 1(3):26, 27 general, 1(3):22, 24 Giant cell astrocytoma, subependymal, 1(3):8, 10

in children over 1 year, 1(5):112, 115 foramen of Monro mass, 1(3):18, 20 intraventricular calcifications, 1(3):62, 65 lateral ventricle mass, 1(3):12, 14 in newborn/infant, 1(5):106, 109 Giant cell tumor epidural mass, 11(5):2,7 extradural lesions, II(5):32, 37 extradural marrow signal, abnormal, 11(5):27,29 sacral mass, adult, II(1):18, 20 vertebral body, 11(3):6,38, 40 Giant serpentine aneurysm, 1(9):6 Glioblastoma multiforme cerebellar mass, 1(7):23, 27 in children over 1 year, 1(5):113, 116 corpus callosum, 1(6):46, 49, 56 cyst with nodule, 1(5):28, 30 cystic mass, solitary, 1(5):16, 18 enlarged deep veins, 1(10):11, 13 ependymal/subependymallesions, 1(3):8, 10 macrocephaly, 1(1):32, 35 midbrain lesion, 1(6):100 multifocal, 1(5):13, 15 multiple brain hyperintensities (T2/FLAIR), 1(5):71,74 multiple enhancing lesions, 1(5):3, 5 in newborn/infant, 1(5):107, 110 parenchymal lesions multiple hyperdense, 1(5):51, 54 multiple hypodense, 1(5):61 solitary hyperdense, 1(5):44, 46 solitary hypodense, 1(5):56, 58 T1 hypointense, T2 hyperintense, 1(5):90 perivascular space enhancing lesions, 1(6):76, 78 periventricular enhancing lesions, ](3):58, 60 pial enhancement, 1(2):16, 18 posterior fossa neoplasms, adult, 1(7):41 ring-enhancing lesion, solitary, ](5):6, 8 spinal cord, 11(7):3 thalamic lesion, unilateral, 1(6):90 thick cortex, 1(6):9, 13 vermis mass, 1(7):29, 31 white matter lesions confluent, 1(6):34, 36 solitary, 1(6):30, 32 Glioma brainstem, pediatric. See Brainstem glioma, pediatric chordoid hyperdense suprasellar mass, 1(8):52 hypothalamus lesion, ](8):49, 51 sellar/juxtasellar calcification, ](8):15, 16 third ventricle mass, genera], 1(3):23, 25 exophytic, II(6):29 exophytic cervicomedullary, 1(7):10, 12 malignant, 1(6):28 multifoca], 1(5):80, 81

::s

Q.

I'D

><

XIX

INDEX :l(

Q,j

"'CI C

-

optic nerve, 1(4):46, 48 optic pathway, in children over 1 year, 1(5):112, 114

tecta I cerebral aqueduct/periaqueductal

lesion,

1(3):28,29

midbrain lesion, 1(6):100, 103 pineal region mass, 1(8):2, 4 third ventricle mass, 1(3):23, 25 Gliomatosis cerebri asymmetric cerebral hemispheres, 1(6):3, 7 basal ganglia, T2 hyperintense, 1(6):71 bithalamic lesions, 1(6):92, 94 cerebral aqueduct/periaqueductallesion, 1(3):29, 31 in children over 1 year, 1(5):113 corpus callosum mass, 1(6):56, 57 multiple brain hyperintensities (T2/FLAIR), 1(5):71,74

parenchymal lesions, 1(5):90 thick cortex, 1(6):9, 13 white matter lesions, 1(6):31, 34, 39 Glioneuronal tumor of fourth ventricle, rosetteforming, 1(3):33, 1(7):40 Gliosarcoma, 1(4):5, 7 Gliosis, 1(5):64, 66 Globus pallidus lesions, 1(6):86-89 Glutaric aciduria type 1 macrocephaly, 1(1):33, 36 T2 hyperintense basal ganglia, 1(6):71, 73 Gout chronic post-traumatic cervical abnormality, 11(1):2

intervertebral disc endplate irregularity, 11(4):7 vertebral endplate signal abnormality, 11(4):16, 17 Granulocyte colony-stimulation factor, 1(1):6 Granuloma, cholesterol, petrous apex, 1(5):32, 33 Granulomatosis, lymphomatoid, 1(5):80 Granulomatous angiitis enlarged deep veins, 1(10):11, 13 multiple brain hyperintensities (T2/FLAIR), 1(5):76, 78

perivascular space enhancing lesions, 1(6):76, 79 Granulomatous disease, 11(6):20, 21 Gray matter heterotopic ependymal/subependymallesions, 1(3):8, 10 epilepsy, 1(5):118, 120 irregular large ventricles, 1(3):54, 56 subcortical laminar, 1(6):15, 19 Tl/T2 isointense parenchymal lesions, 1(5):95, 97

inborn errors of metabolism, Grisel syndrome, 1I(2):4, 12 Guillain-Barre syndrome atypical, 11(6):36 xx

1(6):15, 19

cauda equina enhancement, diffuse, 11(6):2-3, 4 intradural/extramedullary lesions, solid enhancement, 11(6):14, 16 leptomeningeal enhancement, 11(6):8, 9 pediatric back pain, 11(1):56, 58 Gyral simplification, 1(1):38, 41

H "Hair on end," 1(1):6-7 Hallervorden-Spatz syndrome basal ganglia calcification, 1(6):63, 65 globus pallidus lesions, 1(6):87, 89 T1 hyperintense basal ganglia, 1(6):67, 69 Hangman's C2 fracture cranio-cervical junction acute injury, 11(2):2, 3 craniovertebral junction abnormalities, 11(2):5 kyphosis, 11(1):12 posterior element fracture, 11(3):34 Hardware failure acute back pain/radiculopathy, postoperative, 11(1):31, 34

chronic back pain/radiculopathy,

postoperative,

11(1):37,40 kyphosis, 11(1):12

Hardware malposition, 11(4):3, 5 Hashimoto encephalopathy, 1(5):76, 78 Heart disease, congenital, 1(1):6 Hemangioblastoma cerebellar mass, 1(7):22, 24 cisterna magna mass, 1(4):39, 41 CPA cystic mass, 1(4):28, 30 cyst with nodule, 1(5):28, 30 cystic-appearing posterior fossa lesion, 1(7):35, 38

foramen magnum mass, 1(4):43, 45 fourth ventricle mass, 1(3):32, 35 infratentorial midline cyst, 1(7):14, 16 large brainstem, 1(7):2 medulla lesion, 1(7):10, 13 posterior fossa adult, 1(7):40, 42 pediatric, 1(7):45, 48 solitary cystic mass, 1(5):17, 20 vermis mass, 1(7):28, 30 Hemangioblastoma, spinal cord conus abnormality, 11(7):6, 8 craniovertebral junction abnormalities, 11(2):4, 9 intradural/extramedullary lesions, multiple, 11(6):20, 21

intradural lesion, serpentine, 11(6):18 intramedullary lesions multiple, 11(7):12, 13 solid enhancement, 11(7):14, 16 T2 hyperintense, T1 isointense, 11(7):31, 32 T1 hypointense, 11(7):28 intramedullary mass, 11(7):3, 4

INDEX myelopathy, 1I(7):48, SO Hemangioendothelioma, 1(10):3 Hemangioma aggressive, 11(3):12, 14 atypical, 11(3):56,57 calvarial, 1(2):20 capillary, 1I(6):34 cavernous sinus mass, unilateral, 1(10):15 dural sinus, hyperdense, 1(10):27 dural sinus lesion, 1(10):3, 7 epidural, 11(5):3,6, 12 extradural lesions, solid enhancement, 1I(5):16--17,19 extradural marrow signal, abnormal, 11(5):26 extraosseous, 1I(5):30, 31, 33, 35 lAC mass, 1(4):25 Masson, 1(10):27 multiple lucent skull lesions, 1(1):23, 25 scalp mass, 1(1):4 skull "hair on end," 1(1):6, 7 lytic lesion, solitary, 1(1):18, 21 sclerotic lesion, solitary, 1(1):27, 29 soft tissue, 1I(5):10 thickened bony trabeculae, 1I(3):46 vertebral body diffuse T1 hyperintense signal, 11(3):48,49 flattened, solitary, 11(3):6 focal sclerosis, 11(3):42 focal T1 hyperintense signal, 11(3):50 vertebral endplate signal abnormality, 1I(4):16 Hemangiopericytoma epidural mass, brain, 1(4):5, 7 extra-axial lesions, T2 hypointense, 1(4):69 extra-axial mass, hyperdense, 1(4):74 extradural lesions, solid enhancement, 11(5):17, 19

extradural marrow signal, abnormal, 11(5):27, 29 falx lesions, 1(2):12, 13 lumbar soft tissue mass, pediatric, 1I(5):43, 45 posterior fossa neoplasms, adult, 1(7):40, 43 Hematoma. See also Contusion-hematoma, spinal cord epidural mass, 11(5):2,4. See also Epidural hematoma epidural-subdural. See Epidural-subdural hematoma intracerebral. See Intracerebral hematoma paraspinal, 11(5):22 retroperitoneal, 11(1):48 subdural. See Subdural hematoma subgaleal, 1(1):4 Hematopoiesis, extramedullary cavernous sinus lesions, bilateral, 1(10):19 dural-based masses multiple, 1(2):8, 10 solitary, 1(2):5, 7

dural sinus, hyperdense (mimic), 1(10):27 dural sinus lesion, 1(10):3 epidural mass brain, 1(4):5, 7 spine, 11(5):3,7 extra-axial lesions, T2 hypointense, 1(4):69, 71 extra-axial mass, hyperdense, 1(4):74, 75 extradural lesions multiple, 11(5):12, 13 solid enhancement, 11(5):17, 19 T1 hypointense, 1I(5):33, 35 extradural marrow signal, abnormal, 1I(5):27 falx lesions, 1(2):12, 13 paraspinal mass, ventral/lateral, 11(5):8,9 thick dura or arachnoid, generalized, 1(2):14 thick skull, generalized, 1(1):9, 11 vertebral body, diffuse T1 hypointense signal, 11(3):53 Hemimegalencephaly asymmetric lateral ventricles, 1(3):51 epilepsy, 1(5):119, 123 irregular large ventricles, 1(3):55, 57 macrocephaly, 1(1):32 sporadic or familial, 1(6):3, 6 thick cortex, 1(6):8-9, 11 of tuberous sclerosis, 1(6):3, 6 Hemiparesis/hemiplegia, 1I(1):10 Hemodialysis arthropathy, 11(1):2 dural calcification, 1(2):2 spondyloarthropathy intervertebral disc end plate irregularity, 11(4):7,9 vertebral endplate signal abnormality, 1I(4):16, 17 Hemolytic uremic syndrome, 1(6):70 Hemorrhage cerebellar, remote, 1(7):23, 27 germinal matrix, 1(3):67, 70 intracranial. See Intracranial hemorrhage intraventricular. See Intraventricular hemorrhage retroperitoneal, 11(5):8 subacute (mimic), 1(4):58 subarachnoid. See Subarachnoid hemorrhage vertebral bone marrow, 11(3):50, 51 Hepatic encephalopathy chronic, enlarged sulci, 1(4):9 globus pallidus lesions, 1(6):86, 88 T1 hyperintense basal ganglia, 1(6):66, 68 Hereditary spastic paraplegia with thin corpus callosum, 1(6):41 Herniation. See also Intervertebral disc herniation; Spinal cord herniation intracranial syndromes asymmetric lateral ventricles, 1(3):50, 52 cisterna magna mass, 1(4):38, 39

::::J Q.

t'll

><

xxi

INDEX ><

Q,/ ""Cl

C

XXII

low cerebellar tonsils, 1(7):32, 33 small ventricles, 1(3):48, 49 tonsillar, 1(4):42, 43 transtentorial, ascending, 1(8):8, 9 Herpes encephalitis congenital, 1(3):66, 68 cortical enhancement, 1(6):28 cortical hyperintensity Tl/FLAIR, 1(6):24, 26 multiple brain hyperintensities (T2/FLAIR), 1(5):70, 73 parenchymal lesions, 1(5):91, 103 thick cortex, 1(6):8, 9 Herpes zoster, 1(4):47 Herpetic neuritis, trigeminal, 1(10):23, 25 HIE. See Hypoxic-ischemic encephalopathy (HIE) Hippocampal sulcus remnants, 1(5):22-23, 25 Histiocytoma, malignant fibrous, 11(5):10 Histiocytosis, 1(2):20, 1(8):46, 47 HIV infections. See also Opportunistic infections, AIDS congenital basal ganglia calcification, 1(6):62, 64 periventricular calcifications, 1(3):66, 69 Tl hyperintense basal ganglia, 1(6):67, 69 diffuse Tl hypointense signal, vertebral body, 11(3):52,54 encephalitis confluent white matter lesions, 1(6):34, 37 enlarged sulci, generalized, 1(4):9, 10 T2 hyperintense cord lesions, dorsal, 11(7):40, 42-43 Holoprosencephaly (HPE) corpus callosum abnormal shape or configuration, 1(6):47, 51 thin, 1(6):41, 45 dorsal cyst, 1(4):52, 53 infundibular stalk, absent/thin, 1(8):44 interhemispheric fissure cysts, 1(4):21, 23 irregular large ventricles, 1(3):55, 57 variants, 1(6):47, 51 Huntington disease bilateral basal ganglia lesions, 1(6):81 enlarged sulci, generalized, 1(4):8, 11 large ventricles, 1(3):45, 47 putamen lesions, 1(6):84, 85 T2 hyperintense basal ganglia, 1(6):71 Hydranencephaly, 1(1):33, 36 Hydration status, volume loss secondary to, 1(4):9 Hydrocephalus macrocephaly, 1(1):32, 33-34 normal pressure, 1(3):45 obstructive asymmetric lateral ventricles, 1(3):50, 52 corpus callosum, abnormal shape or configuration, 1(6):47, 50 corpus callosum, thin, 1(6):40-41, 44 corpus callosum holes, 1(6):52, 53 effaced sulci, generalized, 1(4):12, 14

infratentorial midline cyst, 1(7):14, 16 intrasellar mass, cystic, 1(8):22, 23 large ventricles, 1(3):44, 45 periventricular T2/FLAIR lesions, 1(3):73, 75 pineal region mass, 1(8):3, 5 posterior fossa lesion, cystic-appearing, 1(7):34, 37 suprasellar cystic mass, 1(8):36, 37 thin cortex, 1(6):14,16-17 thin skull, generalized, 1(1):14 severe, longstanding communicating, Il(3):18 shunted, 1(1):8, 10 suprasellar mass, pediatric, 1(8):30 Hydrosyringomyelia, 11(3):18 Hygroma, subdural, 1(4):50 Hyperalimentation, 1(6):66, 68, 86 Hyperattenuating artery, 1(9):8-9 Hyperextension injury, cervical post-traumatic bony abnormality, 11(1):4,5 posterior element fracture, 11(3):34 vertebral body fracture, 11(3):28,30 Hyperextension-rotation injury, cervical, Il(I):4 Hyperflexion injury, cervical acute upper extremity pain or weakness, 11(1):42,44 CI-C2 instability, 11(2):12 kyphosis, 11(1):12 post-traumatic bony abnormality, 11(1):4 posterior element fracture, Il(3):34 vertebral body fracture, 11(3):28,30 Hyperflexion-rotation injury, cervical acute upper extremity pain or weakness, 11(1):42 post-traumatic bony abnormality, 11(1):4,5 posterior element fracture, Il(3):34 Hyperostosis, meningioma-associated, 1(1):26, 28 Hyperostosis frontalis interna normal variants, skull, 1(1):2, 3 thick skull, 1(1):8, 9, 12 Hyperparathyroidism basal ganglia, 1(6):62, 67 dural calcification, 1(2):2, 3 lucent skull lesions, multiple, 1(1):22-23, 25 parenchymal calcifications, multiple, 1(5):41 sclerotic skull lesions, multiple, 1(1):30, 31 thick skull, 1(1):8-9, 11 thin skull, 1(1):14, 15 vascular calcifications, 1(9):10 Hypertension, chronic, 1(5):82, 83 Hypertensive encephalopathy acute basal ganglia, T2 hyperintense, 1(6):71, 73 bithalamic lesions, 1(6):92, 95 corpus callosum splenium lesion, 1(6):59 cortical enhancement, 1(6):28, 29 cortical hyperintensity Tl/FLAIR, 1(6):24, 26 effaced sulci, generalized, 1(4):13, 15 multiple brain hyperintensities (T2/FLAIR), 1(5):64,68

INDEX parenchymal lesions, multiple hyperdense, 1(5):50-51, 53 parenchymal lesions, multiple hypodense, 1(5):61, 63 parenchymal lesions, Tl hyperintense, 1(5):103 pontine lesion, 1(7):6 restricted diffusion, 1(5):99, 101 chronic confluent white matter lesions, 1(6):34, 36 large ventricles, 1(3):44 multiple brain hyperintensities (T2/FLAIR), 1(5):64,67 parenchymal lesions, Tl hypointense, T2 hyperintense, 1(5):90, 92 Hypertrophic neuropathy intradural/extramedullary lesions no enhancement, 11(6):12, 13 ring/peripheral enhancement, 11(6):23,25 solid enhancement, 11(6):15 leptomeningeal enhancement, 11(6):9 Hypertrophic pachymeningitis, 1(2):12, 14, 15 Hypervitaminosis A or D, 11(3):44 Hypoglycemia basal ganglia, Tl hyperintense, 1(6):67 corpus callosum splenium lesion, 1(6):59 cortical enhancement, 1(6):28 cortical hyperintensity Tl/FLAIR, 1(6):25, 27 restricted diffusion, 1(5):99 Hypomelanosis of Ito, 1(6):74, 75 Hypomyelination corpus callosum, abnormal shape or configuration, 1(6):46 corpus callosum, thin, 1(6):41, 44 microcephaly, 1(1):38-39, 42 thick cortex, 1(6):8, 10 white matter lesions, confluent, 1(6):34, 38 Hypoparathyroidism, 1(6):62, 67 Hypoperfusion injury, 1(6):92, 94 Hypophosphatasia, 1(1):14, 15 Hypophysitis, lymphocytic. See Lymphocytic hypophysitis Hypoplastic pedicle, 11(3):16 Hypothalamic/pituitary axis metastasis, 1(8):48 Hypothyroidism basal ganglia calcification, 1(6):62, 64 cerebellar atrophy, 1(7):19, 20 globus pallidus lesions, 1(6):87, 89 multiple parenchymal calcifications, 1(5):41, 43 Tl hyperintense basal ganglia, 1(6):67, 69 white matter lesions, confluent, 1(6):34, 39 Hypoxic-ischemic encephalopathy (HIE) asymmetric cerebral hemispheres, 1(6):2-3, 5 basal ganglia bilateral lesions, 1(6):80, 82 Tl hyperintense, 1(6):66, 68 T2 hyperintense, 1(6):70, 71

bithalamic lesions, 1(6):92 corpus callosum splenium lesion, 1(6):58, 60 cortical hyperintensity Tl/FLAIR, 1(6):25 effaced sulci, generalized, 1(4):12 enlarged sulci, generalized, 1(4):8 globus pallidus lesions, 1(6):86, 87 microcephaly, 1(1):38, 39 parenchymal lesions, Tl hyperintense, 1(5):103, 105 putamen lesions, 1(6):84 small ventricles, 1(3):48, 49 term neonate abnormal shape or configuration of corpus callosum, 1(6):47 bithalamic lesions, 1(6):92, 94 globus pallidus lesions, 1(6):86, 87 putamen lesions, 1(6):84, 85 Tl hyperintense basal ganglia, 1(6):66, 68 T2 hyperintense basal ganglia, 1(6):70, 71 Hypoxic-ischemic injury, NOS, 1(6):62, 64

I Iatrogenic conditions, 1(10):15 Inborn errors of metabolism acute presentation, 1(3):48, 49 bithalamic lesions, 1(6):93 end-stage, 1(3):45 gray matter disorders, 1(6):15, 19 macrocephaly, 1(1):33 "Incidentaloma," pituitary, 1(8):12 Infant. See a/so Prematurity; specific disorders, in newborn/infant normal kyphosis, 11(1):14 normal skull, 1(1):14 small ventricles, normal, 1(3):48 Infections bacterial, 1(5):80, 81, 11(7):20,21 bilateral basal ganglia lesions, 1(6):81, 83 CMY. See Cytomegalovirus (CMV) infections congenital, 1(6):62 focal or multifocal, 1(7):6, 9 HIY. See HIV infections; Opportunistic infections, AIDS intervertebral disc space. See Intervertebral disc space infections medulla lesion, 1(7):11, 13 midbrain lesion, 1(6):101 Nocardia, 1(5):80, 81 parenchymal, 1(5):60 postoperative. See Postoperative complications, infection TORCH. See TORCH infections Infiltrative disorders, 1(7):7, 9, 11 Infratentorial brain parenchyma, 1(7):2-49 brainstem large, 1(7):2-3 XXIII

INDEX ><

CIJ "'t:l

C

xxiv

small, 1(7):4-5 cerebellum atrophy, 1(7):18-21 mass, 1(7):22-27 low cerebellar tonsils, 1(7):32-33 medulla lesion, 1(7):10-13 midline cyst, 1(7):14-17 pontine lesion, 1(7):6-9 posterior fossa adult neoplasms, 1(7):40-43 cystic-appearing lesion, 1(7):34-39 pediatric neoplasms, 1(7):44-49 vermis mass, 1(7):28-31 Instrumen ta tion/implants intervertebral disc, II(4):12, 13 intramedullary lesions, II(7):26 Insufficiency fracture pedicle, II(I):8, II(3):42, 43 sacral, II(I):26, 28, 53, 55 Interhemispheric fissure cysts, 1(4):20-23 Interior vena cava occlusion, II(6):18, 19 Intervertebral disc, II(4):2-17 anular tear adult back pain, 11(1):52,54 T2 hyperintense disc, II(4):14, 15 bulge adult back pain, II(I):52 disc contour abnormality, II(4):2, 3 lower extremity pain, II(I):48, 49 normal extradural marrow signal, II(5):22 endplate. See Intervertebral disc end plate extrusion disc contour abnormality, II(4):2, 4 foraminal, 11(1):30,32, II(5):22, 23 free fragment, II(4):2 herniation. See Intervertebral disc herniation instability, post-traumatic, II(4):12 normal variant, II(4):14 protrusion, II(4):2 pseudobulge, II(4):2, 3 sequestered fragment, II(5):14, 15 T2 hyperintense, II(4):14-15 Tl hypointense, II(4):12-13 vertebral end plate contour abnormality, II(4):10-11 signal abnormality, II(4):16-17 Intervertebral disc endplate degenerative changes aggressive bony lesion, II(3):24, 26 endplate contour abnormality, II(4):1O endplate irregularity, II(4):6, 7 extradural lesions, no enhancement, II(5):14, 15 signal abnormality, II(4):16 vertebral body, focal sclerosis, II(3):42, 43 vertebral body, focal Tl hyperintense signal, 11(3):50,51

vertebral body, focal Tl hypointense signal, II(3):56, 57 disc contour abnormality, II(4):2-5 irregularity, II(4):6-9 Intervertebral disc herniation back pain/radiculopathy adult, II(I):52, 53 pediatric, II(I):57 postoperative, acute, II(I):30, 32 cervical acute upper extremity pain or weakness, II(I):42, 43-44 myelopathy, II(7):48, 52 normal extradural marrow signal, II(5):22, 23 compression, II(6):3, 5 epidural mass, II(5):2, 3 extradural lesions T2 hyperintense, Tl isointense, II(5):36, 37 Tl hypo intense, II(5):32, 33 T2 hypointense, Tl hypo intense, II(5):40 lower extremity pain, II(I):48, 49 lumbar, II(5):22, II(6):36 multiple extradural lesions, II(5):12 recurrent disc contour abnormality, II(4):2, 4 postoperative back pain/radiculopathy, II(I):30, 31, 36, 38 thoracic, II(5):22, 11(7):48 traumatic acute upper extremity pain or weakness, II(I):42, 44 cranio-cervical junction acute injury, II(2):2 myelopathy, 11(7):48,52 Intervertebral disc space infections pyogenic, 1I(4):6-7, 8 T2 hyperintense disc, 1I(4):14, 15 tuberculous, II(4):7, 8 Intracerebral hematoma hyperacute, 1(5):94, 95 parenchymal lesions solitary hypodense, 1(5):57, 59 Tl hyperintense, 1(5):102, 104 Tl/T2 hyperintense, 1(5):86, 87 resolving, 1(5):17,19,57,59 restricted diffusion, 1(5):98 subacute late, parenchymal lesions, 1(5):102, 104 ring-enhancing lesions, 1(5):6, 8, 13 Intracranial hemorrhage hypertensive cerebellar mass, 1(7):22, 23 corpus callosum, abnormal shape or configuration, 1(6):47, 51 large brainstem, 1(7):2 parenchymal lesions, 1(5):44, 45, 50, 52 pontine lesion, 1(7):6, 8 putamen lesions, 1(6):84

INDEX thalamic lesion, unilateral, 1(6):90, 91 spontaneous, 1(4):16, 18 Intracranial hypertension, idiopathic, 1(4):13, 15, 1(8):22 Intracranial hypotension cisterna magna mass, 1(4):39, 41 dural sinus lesion, 1(10):3, 7 enlarged deep veins, 1(10):11, 13 extra-axial fluid collection, CSF-like, 1(4):50, 51 falx lesions, 1(2):12 foramen magnum mass, 1(4):43 idiopathic, 1(3):48, 49 intrasellar lesion, 1(8):20 large brainstem, 1(7):2, 3 low cerebellar tonsils, 1(7):32, 33 midbrain lesion, 1(6):101 pineal region mass, 1(8):3, 5 pituitary gland enlargement, 1(8):18, 19 prepontine cistern mass, 1(4):33, 35 secondary, 1(3):48 small ventricles, 1(3):48, 49 thick dura or arachnoid, generalized, 1(2):14, 15 Intradural-extramedullary area, spine, 11(6):2-37 cauda equina enhancement, diffuse, 11(6):2-5 intradural/extramedullary lesions multiple, 11(6):20-21 no enhancement, 11(6):12-13 ring/peripheral enhancement, 11(6):22-25 solid enhancement, 11(6):14-17 T1 hyperintense, 11(6):26-27 T2 hyperintense, T1 isointense, 11(6):34-35 T1 hypointense, 11(6):28-31 T1 hypointense, T2 hypointense, 11(6):32-33 intradural lesion, serpentine, 11(6):18-19 leptomeningeal enhancement, 11(6):8-11 subarachnoid space narrowing, 11(6):6-7 Intramedullary area, spine, 11(7):2-53 conus abnormality, 11(7):6-9 intramedullary mass, 11(7):2-5 lesions diffuse/ill-defined enhancement, 11(7):20-23 no enhancement, 11(7):18-19 ring/peripheral enhancement, 11(7):24-25 solid enhancement, 1l(7):14-17 T1 hyperintense, 11(7):34-37 T2 hyperintense, T1 isointense, 1l(7):30-33 T1 hypointense, 11(7):28-29 T1 hypointense, T2 hypointense, 11(7):26-27 myelopathy, 11(7):48-53 small/atrophic spinal cord, 1l(7):10-11 Intrathecal gas, postoperative, 11(6):28 Intraventricular calcifications, 1(3):62-65 Intraventricular hemorrhage asymmetric lateral ventricles, 1(3):50, 52 cerebral aqueduct/periaqueductallesion, 1(3):29, 31 FLAIRhyperintense CSF, 1(4):64, 66

intraventricular calcification (mimic), 1(3):62 large ventricles, 1(3):44 lateral ventricle mass, 1(3):12, 13 macrocephaly, 1(1):32, 34 T1 hyperintense CSF,1(4):62, 63 Intraventricular mass, "bubbly-appearing," 1(3):36-39 Intraventricular synechiae or adhesions, 1(3):51, 53 Intraventricular webs or adhesions, 1(3):54-55 Iron deficiency anemia, 1(1):6, 9 Ischemia. See also Cerebral ischemia-infarction, acute arterial, bithalamic lesions, 1(6):92, 93 cranial nerve enhancement, 1(4):47 venous, 1(6):81, 92, 94

J Japanese encephalitis, 1(6):67 Jefferson Cl fracture CI-C2 instability, 11(2):12 cranio-cervical junction acute injury, 11(2):2,3 craniovertebral junction abnormalities, 11(2):4 posterior element fracture, 11(3):34 Juvenile idiopathic arthritis cervical abnormality, chronic post-traumatic, 11(1):2,3 cervical bony fusion, 11(3):4-5 congenital vertebral anomalies, 11(3):2,3 craniovertebral junction abnormalities, 11(2):4,6 dysmorphic vertebral body, 11(3):10, 11 kyphoscoliosis, child, 11(1):14, 15 kyphosis, 1l(1):12 odontoid deformity, 1l(2):14, 15 post-traumatic lower cervical bony abnormality, 1l(1):4 soft tissue calcification, paraspinal, 11(5):20, 21 vertebral body scalloping or widened canal, 1l(3):18, 19 Juxtasellar region. See Pineal region

K Kaposi sarcoma, 1(1):4 Kernicterus bithalamic lesions, 1(6):93 globus pallidus lesions, 1(6):86-87, 89 multiple brain hyperintensities (T2/FLAIR), 1(5):77, 79 T1 hyperintense basal ganglia, 1(6):66, 69 T1 hyperintense parenchymal lesions, 1(5):102 Klippel-Feil spectrum cervical abnormality, chronic post-traumatic, 11(1):2 cervical bony fusion, 11(3):4 dysmorphic vertebral body, 1l(3):10 kyphoscoliosis, child, 1l(1):14

xxv

INDEX ><

CI.I "'C C

kyphosis, congenital, 11(1):10, 12 lower cervical bony abnormality, posttraumatic, 11(1):4,5 odontoid deformity, 11(2):14, 15 scoliosis, congenital, 11(1):10 vertebral anomalies, congenital, 11(3):2 Krabbe disease, 1(6):93,95 Ktimmel disease dysmorphic vertebral body, 11(3):10 flattened vertebral body, solitary, 11(3):6 focal T1 hypointense signal, vertebral body, 11(3):56 lumbar bony trauma, 11(1):8 T1 hypointense intervertebral disc, 11(4):12, 13 thoracic bony trauma, 11(1):6 vertebral body fracture, 11(3):29, 31 Kyphoplasty, 11(3):42 Kyphoscoliosis, child, 11(1):14-15 congenital, 11(1):14-15 traumatic, 11(1):14 tumors, 11(1):14, 15 Kyphosis, 11(1):12-13 chronic post-traumatic cervical abnormality, 11(1):2,3 congenital congenital vertebral anomalies, 11(3):2 kyphoscoliosis, child, 11(1):14 lumbar bony trauma, 11(1):8 myelopathy, 11(7):48 scoliosis, 11(1):10, 11 thoracic bony trauma, 11(1):6,7 vertebral body fracture, 11(3):28,31 idiopathic, 11(1):12 kyphoscoliosis, child, 11(1):14 thoracic bony trauma, 11(1):6,7 vertebral body fracture, 11(3):29,31 myelopathy, 11(7):48 normal in infants, 11(1):14 post-traumatic lower cervical bony abnormality, 11(1):4 postural, I1(1):12

L Lacunar infarction bilateral basal ganglia lesions, 1(6):80, 81 corpus callosum holes, 1(6):52, 53 multiple brain hyperintensities (T2/FLAIR), 1(5):64,67 parenchymal lesions CSF-like, 1(5):22, 24 T1 hypointense, T2 hyperintense, 1(5):90 solitary white matter lesion, 1(6):30, 31 subacute, 1(5):7 thalamic lesion, unilateral, 1(6):90 Lacunar skull Chiari 2, 1(1):23, 25 xxvi

thin skull, generalized, 1(1):14, 15 Lambdoid defects, 1(1):23 Laminar necrosis, cortical, 1(5):103 Langerhans cell histiocytosis (LCH) aggressive bony lesion, 11(3):24,27 back pain, pediatric, 11(1):57 choroid plexus lesions, 1(3):6, 7 cranial nerve enhancement, 1(4):47 dural-based masses, 1(2):5, 8, 10 ependymal enhancement, 1(3):41, 43 ependymal/subependymallesions, 1(3):9 epidural mass, brain, 1(4):5, 7 extradural lesions, 11(5):17, 19 flattened vertebral body, solitary, 11(3):6,7 hypothalamus lesion, 1(8):48, 50 kyphoscoliosis, child, 11(1):14 lateral ventricle mass, 1(3):13 medulla lesion, 1(7):11 perivascular space enhancing lesions, 1(6):77, 79 pituitary gland enlargement, 1(8):18, 19 pontine lesion, 1(7):7 scalp mass, 1(1):4, 5 skull base, 1(10):19, 21 skull lesions lytic, solitary, 1(1):18, 20 multiple lucent, 1(1):22, 25 suprasellar mass enhancing, 1(8):42, 43 general, 1(8):25, 27 pediatric, 1(8):31, 33 T1 isointense, 1(8):54 third ventricle mass, general, 1(3):23 thoracic bony trauma, 11(1):6 Lateral flexion injury, cervical acute upper extremity pain or weakness, 11(1):42,44--45 kyphoscoliosis, child, 11(1):14 post-traumatic bony abnormality, 11(1):4 posterior element fracture, 11(3):34 scoliosis, 11(1):10 Lateral ventricles, asymmetric, 1(3):2, 3 LCH. See Langerhans cell histiocytosis (LCH) Leigh syndrome basal ganglia bilateral lesions, 1(6):80 calcification, 1(6):63, 65 T2 hyperintense, 1(6):71, 73 cerebral aqueduct/periaqueductallesion, 1(3):29,

31 globus pallidus lesions, 1(6):86, 88 multiple brain hyperintensities (T2/FLAIR), 1(5):70, 72 putamen lesions, 1(6):84,85 Leptomeningeal cyst, 1(1):19, 21, 1(4):52 Leukemia back pain adult, 11(1):52 pediatric, 11(1):56, 59

INDEX cavernous sinus lesions, bilateral, 1(10):19, 21 in children over 1 year, 1(5):113, 117 cranial nerve enhancement, 1(4):47 dural-based masses, 1(2):5, 7, 9, 11 dural sinus, hyperdense, 1(10):27, 29 dural sinus lesions, 1(10):3, 7 dural tail sign, 1(2):20, 21 epidural masses, 1(4):5, 7, Il(5):3 extra-axial lesion, T2 hypointense, 1(4):69, 71 extra-axial mass, hyperdense, 1(4):74, 75 extradural lesion, Tl hypointense, 11(5):33,35 "hair on end," 1(1):6, 7 hypothalamus lesion, 1(8):49 intradural/extramedullary lesions, 1I(6):14, 16 leptomeningeal enhancemert, II(6):8, 11 multiple hypointense foci on GRE/5WI, 1(5):83 parenchymal lesions multiple hyperdense, 1(5):51, 55 solitary hyperdense, 1(5):45, 49 Tl hyperintense, 1(5):102 periventricular enhancing lesions, 1(3):59 pituitary gland enlargement, 1(8):18 skull lesions, multiple lucent, 1(1):23 sulcal/cisternal enhancement, 1(4):55 suprasellar mass enhancing, 1(8):42 general, 1(8):25, 29 pediatric, 1(8):31 thick infundibular stalk, 1(8):46 vertebral body diffuse Tl hypointense signal, 1I(3):52, 54 flattened, Il(3):6, 8 Leukodystrophy inherited, 1(5):90 metachromatic confluent white matter lesions, 1(6):34, 37 corpus callosum lesion without mass effect, 1(6):54, 55 intradural/extramedullary lesions, II(6):15 periventricular T2IFLAIRlesions, 1(3):73 Leukoencephalopathy. See also Progressive multifocalleukoencephalopathy (PML) acute hemorrhagic, [(5):51, 55 megalencephaly, 1(1):33, 36 Van der Knaap, [(6):34, 38 Leukomalacia, periventricular corpus callosum abnormal shape or configuration, 1(6):46, 49 lesion without mass effect, 1(6):54, 55 irregular large ventricles, [(3):54, 56 multiple brain hyperintensities (T2/FLA[R), 1(5):65, 69 periventricular T2/FLAIRlesions, 1(3):72, 74 "pulvinar sign," 1(6):96, 97 Ligament abnormalities, congenital, 1I(2):5 Ligamentous hypertrophy, II(5):23 Ligamentum flavum

degenerated hypertrophic, Il(5):32, 33-34 hypertrophy, Il(5):2, 4, 12 ossification extradural lesions, II(5):14, 40, 41 myelopathy, Il(7):48 normal extradural marrow signal, Il(5):23, 25 Liliequist membrane, 1(4):2 Limb length inequality, Il(I):10 Limbus vertebra disc contour abnormality, Il(4):3, 5 dysmorphic vertebral body, II(3):10 extradural lesions, no enhancement, 1I(5):14 lumbar bony trauma, II(I):8, 9 thoracic bony trauma, II(I):6 vertebral anomalies, congenital, 1I(3):2, 3 vertebral body, focal Tl hypointense signal, II(3):56 vertebral body fracture, II(3):29 vertebral endplate contour abnormality, II(4):10 Lipoidal contrast (mimic), 1(4):58 Lipoma choroid plexus, 1(3):6 corpus callosum, abnormal shape or configuration, 1(6):46, 49 corpus callosum mass, [(6):56, 57 CPA-lAC mass, 1(4):25, 27 dural sinus lesion, 1(10):3 extra-axial masses, hypodense, 1(4):76, 78 fat in sulCi/cisterns/ventricles, [(4):58 fourth ventricle mass, 1(3):33 hypothalamus lesion, 1(8):48 intradural/extramedullary lesions, II(6):26, 27 intramedullary lesions, Il(7):34-35, 37 Meckel cave lesion, 1(10):23 parenchymal lesions, 1(5):32, 87 pineal region mass, 1(8):3, 4 quadrigeminal cistern mass, 1(8):8, 9 scalp mass, 1(1):4 soft tissue, paraspinal muscle abnormalities, 1I(5):1O spinal extradural lesions, no enhancement, Il(5):14 intramedullary mass, Il(7):3 lumbar soft tissue mass, pediatric, Il(5):42, 44 suprasellar mass general, 1(8):25, 27 pediatric, 1(8):31, 34 Tl hyperintense, 1(8):56 tectal plate lesion, 1(6):98, 99 terminal conus abnormality, 1I(7):7, 9 TI hyperintense extradural lesion, Il(5):30, 31 vertebral body scalloping or widened canal, 1I(3):18 Lipomatosis encephalocraniocutaneous XXVII

INDEX ><

Q,j

"C C

-

asymmetric cerebral hemispheres, 1(6):3, 7 fat in sulci/cisterns/ventricles, 1(4):58, 59 fat-like lesions, 1(5):32 fourth ventricle mass, 1(3):33, 35 epidural epidural mass, 11(5):2,4 extradural lesion, 11(5):14, 15,30 normal extradural marrow signal, 11(5):23,25 Lipomyelomeningocele/lipomyelocele conus abnormality, 11(7):7,9 extradural lesion, 11(5):30,31 intradural/extramedullary lesion, 11(6):26,27 lumbar soft tissue mass, pediatric, 11(5):42,43 sacral deformity, 11(1):26-27, 29 vertebral anomalies, congenital, 11(3):2 Liponeurocytoma, cerebellar, 1(7):40 Liposarcoma, soft tissue, 11(5):8 Lissencephaly type 1 epilepsy, 1(5):119 thick cortex, 1(6):9, 12 Lithium intoxication, 1(7):18 Longitudinal ligament ossification anterior, 11(1):2,3 posterior cervical abnormality, chronic post-traumatic, 11(1):2,3 cervical bony fusion, 11(3):4,5 craniovertebral junction abnormalities, 11(2):4 disc contour abnormality, 11(4):3,4 epidural mass, 11(5):3,5 extradural lesions, multiple, 11(5):12,13 extradural lesions, no enhancement, 11(5):14 extradural lesions, T1 hypo intense, 11(5):33,

35 extradural lesions, T2 hypointense, Tl hypointense, 11(5):40 myelopathy, 11(7):48,51 normal extradural marrow signal, 11(5):23 subarachnoid space narrowing, 11(6):6,7 with fatty marrow, 11(5):30,31 Longus coli. See Calcific tendinitis, longus coli Lower extremity pain, 11(1):48-51 Lumbar spine acute back pain/radiculopathy, postoperative, 11(1):30,32 bony trauma, 11(1):8-9 lateral compression fracture, 11(1):10 soft tissue mass, pediatric, 11(5):42-45 Lung abnormalities, 11(1):10 Lung carcinoma, 11(3):38,39 Lyme disease corpus callosum lesion without mass effect, 1(6):54 cranial nerve enhancement, 1(4):47, 49 multiple brain hyperintensities (T2/FLAIR), 1(5):76, 78 xxviii

multiple enhancing lesions, 1(5):3 parenchymal lesions, multiple hypodense, 1(5):61 periventricular enhancing lesions, 1(3):58, 61 periventricular T2/FLAIR lesions, 1(3):72, 75 pial enhancement, 1(2):17, 19 ring-enhancing lesions, multiple, 1(5):13, 15 Lymphadenopathies, 11(5):8 Lymphatic malformation, 11(5):43,45 Lymphocele, retroperitoneal, 11(5):8 Lymphocytic hypophysitis dural tail sign, 1(2):20, 21 hypothalamus lesion, 1(8):48, 50 intrasellar lesion, 1(8):20, 21 pituitary gland enlargement, 1(8):18,19 suprasella r mass enhancing, 1(8):42, 43 general, 1(8):25, 28 pediatric, 1(8):31, 35 T1 isointense, 1(8):54, 55 thick infundibular stalk, 1(8):46, 47 Lymphoma. See also Lymphoma, primary CNS aggressive bony lesion, 11(3):24,26 cauda equina enhancement, diffuse, 11(6):3,4 cranial nerve enhancement, 1(4):47, 49 dural sinus lesion, 1(10):3, 6 epidural brain mass, 1(4):4, 6 disc contour abnormality, 11(4):2 spinal mass, 11(5):3,6 extradural lesions solid enhancement, 11(5):16,18 T2 hyperintense, Tl isointense, 11(5):37 T1 hypointense, 11(5):33, 35 extradural marrow signal, 11(5):23,26, 28 extramedullary, 11(2):4,8, 10 facet abnormality, non-traumatic, 11(3):32,33 hypothalamus lesion, 1(8):49, 50 intradural/extramedullary lesions, 11(6):14,16 intramedullary lesion or mass, 11(7):3,15 intravascular (angiocentric) confluent white matter lesions, 1(6):34, 39 enlarged deep veins, 1(10):11, 13 multiple brain hyperintensities (T2/FLAIR), 1(5):76-77, 79 multiple enhancing lesions, 1(5):3, 5 multiple hypodense parenchymal lesions, 1(5):61 perivascular space enhancing lesions, 1(6):76, 78 leptomeningeal enhancement, 11(6):8,10 lumbar soft tissue mass, pediatric, 11(5):42,44 metastatic, intracranial cavernous sinus lesions, bilateral, 1(10):18, 20 cavernous sinus mass, unilateral, 1(10):14, 16 dural-based mass, 1(2):4, 6, 8, 10 dural tail sign, 1(2):20

INDEX extra-axial lesions, T2 hypointense, 1(4):68-69,71 extra-axial mass, hyperdense, 1(4):74 hyperdense dural sinus, 1(10):27, 29 lucent skull lesions, multiple, 1(1):23 medulla lesion, 1(7):10 suprasellar mass, general, 1(8):25, 29 thick dura or arachnoid, generalized, 1(2):14 paraspinal mass, ventral/lateral, 11(5):8 parenchymal, 1(5):80 pontine lesion, 1(7):6 posterior fossa neoplasms, adult, 1(7):40 sacral mass, adult, 11(1):18,20 sacrococcygeal mass, pediatric, 11(1):22,24 scalp mass, 1(1):4 spondylolisthesis, 11(3):20 suprasellar mass, enhancing, 1(8):42 thickened bony trabeculae, 11(3):46,47 vertebral body diffuse sclerosis, 11(3):44,45 diffuse Tl hypointense signal, 11(3):52 flattened, multiple, 11(3):8 fracture, 11(3):28 Lymphoma, primary CNS basal ganglia lesions, bilateral, 1(6):80, 82 bithalamic lesions, 1(6):92, 95 corpus callosum, 1(6):46, 49, 56 ependymal enhancement, 1(3):40, 43 ependymal/subependymal lesions, 1(3):8, 11 intrasellar lesion, 1(8):20, 21 lateral ventricle mass, 1(3):13, 15 multiple brain hyperintensities (T2/FLAIR), 1(5):65, 69 multiple enhancing lesions, 1(5):3, 4 parenchymal lesions multiple hyperdense, 1(5):51, 54 solitary hyperdense, 1(5):45, 48 Tl/T2 hyperintense, 1(5):87, 89 Tl/T2 isointense, 1(5):95, 96 periventricular enhancing lesions, 1(3):58, 60 pineal + suprasellar lesions, 1(8):10, 11 pituitary gland enlargement, 1(8):18 restricted diffusion, 1(5):99, 100 ring-enhancing lesions, 1(5):6, 9, 12, 15 suprasellar mass hyperdense, 1(8):52, 53 pediatric, 1(8):31, 35 thick infundibular stalk, 1(8):46 thick septum pellucidum, 1(3):16, 17 third ventricle mass, general, 1(3):23 white matter lesions, confluent, 1(6):34, 39

M Macrocephaly, 1(1):32-37 Macrocrania benign familial, 1(1):32, 33 of infancy, benign, 1(4):9, 11

Magnetic resonance imaging artifacts. See MR artifacts Malformations, congenital, 1(5):23, 27 Manganese toxicity, 1(6):80, 82 Maple syrup urine disease confluent white matter lesions, 1(6):34, 39 globus pallidus lesions, 1(6):87 pontine lesion, 1(7):7 Marchiafava-Bignami disease, 1(6):47, 51, 52, 53 Marfan syndrome, 1(9):6 Marrow. See Bone marrow Mass effect, extrinsic, 1(3):50, 51 Massa intermedia normal, 1(3):22, 23 prominent (Chiari 2), 1(3):22, 24, 26, 27 Masson hemangioma, 1(10):27 Meckel cave lesion, 1(10):22-25 Medial atrial diverticula. See Hydrocephalus, obstructive Median nerve entrapment, 11(1):43,46 Medulla lesions, 1(7):10-13 Medullary infarct lateral, 1(7):10, 11 medial, 1(7):10-11, 13 Medullary veins, enlarged, 1(10):10-13 Medulloblastoma PNET-MB cerebellar mass, 1(7):22, 24 in children over 1 year, 1(5):112, 114 ependymal/subependymallesions, 1(3):8 fourth ventricle mass, 1(3):32, 33 intraventricular calcifications, 1(3):63, 65 in newborn/infant, 1(5):106, 108 parenchymal lesion, solitary hyperdense, 1(5):45, 47 posterior fossa neoplasm, pediatric, 1(7):44, 46

vermis mass, 1(7):28, 29 variants, 1(7):41, 43, 45 Medulloepithelioma in newborn/infant, 1(5):107, 111 posterior fossa neoplasm, pediatric, 1(7):45, 49 Mega cisterna magna cistern and subarachnoid space normal variants, 1(4):2-3 extra-axial fluid collection, CSF-like, 1(4):50, 51 infratentorial midline cyst, 1(7):14, 15 posterior fossa lesion, cystic-appearing, 1(7):34, 35 thin skull, localized, 1(1):16, 17 Megalencephaly large ventricles, 1(3):45, 47 macrocephaly, 1(1):33, 36 with dilated perivascular spaces, 1(6):74, 75 Melanocytoma intradural/extramedullary lesions, Tl hyperintense, 11(6):26 xxix

INDEX intramedullary lesions, T1 hyperintense, II(7):35, 37 meningeal,I(5):102 Melanoma metastases extradural lesion, T1 hyperintense, II(5):30 intradural/extramedullary lesions, T1 hyperintense, II(6):26 parenchymal lesions, T1 hyperintense, 1(5):102, 105 vertebral body, focal T1 hyperintense signal, II(3):50 parenchymal lesions solitary hyperdense, 1(5):45, 48 Tl hyperintense, 1(5):102, 105 Melanosis, neurocutaneous, 1(2):4, 1(4):55, 57 MELAS acute, cortical hyperintensity Tl/FLAIR, 1(6):25 asymmetric cerebral hemispheres, 1(6):3, 6 basal ganglia bilateral lesions, 1(6):80 calcification, 1(6):62, 64 T2 hyperintense, 1(6):71 cortical enhancement, 1(6):28 parenchymal calcifications, multiple, 1(5):41, 43 Melorheostosis, 1(1):8, 30 Meningeal metastases. See also Skull metastases in children over 1 year, 1(5):113,117 dural-based masses, 1(2):4, 6, 8, 9 dural tail sign, 1(2):20 effaced sulci, focal, 1(4):16, 19 effaced sulci, generalized, 1(4):12, 14 falx lesions, 1(2):12 FLAIRhyperintense CSF, 1(4):64, 67 hyperde.nse CSF,1(4):72 hyperdense dural sinus, 1(10):27, 29 hyperdense extra-axial mass, 1(4):74, 75 pial enhancement, 1(2):16, 17-18 prepontine cistern mass, 1(4):32, 34 T2 hypointense extra-axial lesions, 1(4):68, 70 thick dura or arachnoid, generalized, 1(2):14 unilateral cavernous sinus mass, 1(10):14, 16 Meninges, 1(2):2-21 dural-based mass multiple, 1(2):8-11 solitary, 1(2):4-7 dural calcifications, 1(2):2-3 dural tail sign, 1(2):20-21 falx lesions, 1(2):12-13 pial enhancement, 1(2):16-19 thick dura or arachnoid, generalized, 1(2):14-15 Meningioangiomatosis effaced sulci, focal, 1(4):17, 19 parenchymal calcification, 1(5):35, 39 parenchymal lesions, solitary hyperdense, 1(5):45, 49 perivascular space enhancing lesions, 1(6):77, 79 xxx

pial enhancement, 1(2):17, 19 sulcal/cisternal enhancement, 1(4):55, 57 thick cortex, 1(6):9, 13 Meningioma atypical and malignant dural tail sign, 1(2):20 epidural mass, brain, 1(4):5,7 solitary dural-based mass, 1(2):4, 6 calcified disc contour abnormality, II(4):3, 5 intradural/extramedullary lesions, no enhancement, II(6):12 intradural/extramedullary lesions, ring/ peripheral enhancement, II(6):22, 24 intradural/extramedullary lesions, T1 hypointense, II(6):28, 30 intradural/extramedullary lesions, T1 hypo intense, T2 hypointense, II(6):32, 33

suprasellar mass, 1(8):40, 41 cauda equina syndrome, II(6):36, 37 cavernous sinus lesions or mass, 1(10):14, 15, 18, 19

in children over 1 year, 1(5):113 choroid plexus, 1(3):6, 7 cisterna magna mass, 1(4):38, 40 CPA-lAC mass adult, 1(4):24, 25, 1(7):40 pediatric, 1(7):45, 47 craniovertebral junction abnormalities, 11(2):4, 7,9,11 cystic intradural/extramedullary lesions, 11(6):22, 24

solitary cystic mass, 1(5):16, 20 dural-based masses, 1(2):4, 5, 8, 9 dural calcification, 1(2):2, 3 dural sinus, hyperdense, 1(10):27, 29 dural sinus lesion, 1(10):2-3, 6 dural tail sign, 1(2):20 effaced sulci, focal, 1(4):16, 18 epidural mass, brain, [(4):4, 5 extra-axial lesion or mass hyperdense, 1(4):74, 75 T2 hypointense, [(4):68, 70 falx lesions, 1(2):12, 13 foramen magnum mass, 1(4):42, 44 intradural/extramedullary lesions multiple, II(6):20 solid enhancement, 11(6):14,15 T2 hyperintense, T1 isointense, II(6):34 intraosseous, 1(1):27, 29 intrasellar lesion, 1(8):20 intraventricular calcifications, [(3):62, 64 lateral ventricle, 1(3):12, 14, 51 lipomatous, 1(4):58, 59, 1(5):32 Meckel cave lesion, 1(10):22, 24

INDEX parenchymal lesions, Tl/T2 isointense, 1(5):94, 96 pineal region mass, 1(8):2, 4 pituitary gland enlargement, 1(8):18 prepontine cistern mass, 1(4):32, 34 restricted diffusion, 1(5):99 sellar/juxtasellar calcification, 1(8):14, 16 subarachnoid space narrowing, II(6):6 suprasellar mass enhancing, 1(8):42 general, 1(8):24, 25 hyperdense, 1(8):52, 53 Tl hyperintense, 1(8):56, 57 Tl isointense, 1(8):54 thick dura or arachnoid, generalized, 1(2):14, 15 thick skull, localized, 1(1):12 thin skull, localized, 1(1):16, 17 vertebral body scalloping or widened canal, 11(3):18 Meningitis carcinomatous, 1(4):62 chemical, II(6):8-9, 11 complications, 1(3):45, 46 CSF FLAIRhyperintense, 1(4):64, 66 hyperdense, 1(4):72, 73 Tl hyperintense, 1(4):62, 63 dural calcification, 1(2):2 infundibular stalk, 1(8):44, 46, 47 large ventricles, 1(3):44, 46 lymphomatous, 1(4):54, 56 Meckel cave lesion, 1(10):23, 24 microcephaly, 1(1):38, 40 perivascular space enhancing lesions, 1(6):76, 77 pial enhancement, 1(2):16, 17 small ventricles, 1(3):48 spinal cauda equina enhancement, diffuse, 11(6):2,3 intradural/extramedullary lesions, ring/ peripheral enhancement, II(6):22, 24 intradural/extramedullary lesions, solid enhancement, 11(6):14,17 leptomeningeal enhancement, 11(6):8,10 sulcal/cisternal enhancement, 1(4):54, 55 sulci effaced, 1(4):12, 14, 17 enlarged,I(4):8 thick dura or arachnoid, generalized, 1(2):14, 15 tuberculosis, 1(4):54, 56 Meningocele anterior sacral sacral deformity, 11(1):27,29 sacral mass, adult, II(I):18-19, 21 sacrococcygeal mass, pediatric, 11(1):23,24 dorsal spinal, II(3):2, 11(5):43,45 extra-axial fluid collection, CSF-like, 1(4):50 lateral

enlarged neural foramen, 11(3):16, 17 pedicle abnormality, II(3):36 ventral/lateral paraspinal mass, 11(5):8,9 occult intrasacral, II(I):18, 20, 27, 29 MERRF(myoclonus epilepsy with ragged red fibers), 1(6):71, 73 Mesial temporal sclerosis, 1(5):118, 119 Metabolic disorders bilateral basal ganglia lesions, 1(6):81 inherited confluent white matter lesions, 1(6):35, 37 thin corpus callosum, 1(6):41, 45 Metal artifact extradural lesions no enhancement, II(5):14 Tl hypointense, II(5):32 T2 hypointense, Tl hypointense, 11(5):40,41 intradural/extramedullary lesions Tl hyperintense, II(6):26 Tl hypointense, II(6):28, 29 Tl hypointense, T2 hypointense, 11(6):32 vertebral body, focal Tl hypointense signal, 11(3):56,57 Metastases adult back pain, II(I):53, 55 cauda equina syndrome, 11(6):36 choroidal, 1(3):26, 27 cisterna magna mass, 1(4):38-39, 40 CPA-lAC mass, 1(4):24, 26, 1(7):40, 42 cranial nerve enhancement, 1(4):46, 47 CSF disseminated cauda equina enhancement, diffuse, II(6):2,

=-

Q..

~

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3-4 intradural/extramedullary lesions, multiple, 11(6):20,21 intradural/extramedullary lesions, solid enhancement, II(6):14, 16 intradural/extramedullary lesions, T2 hyperintense, Tl isointense, II(6):34, 35 intradural/extramedullary lesions, Tl hypointense, 11(6):28,31 leptomeningeal enhancement, II(6):8, 9 pediatric back pain, II(I):57, 59 CSF/meningeal, 1(10):22, 24 diffuse sclerotic, 1(1):8, 10 dural, 1(4):4, 6 dural sinus lesion, 1(10):3, 6 ependymal/subependymallesions,I(3):8 epidural disc contour abnormality, II(4):2 epidural mass, spinal, II(5):2, 5 extradural lesions, multiple, 11(5):12, 13 extradural lesions, T2 hyperintense, Tl isointense, 11(5):36,39 extradural lesions, Tl hypo intense, II(5):33, 35 subarachnoid space narrowing, 11(6):6,7 XXXI

INDEX >< aJ

"'C

C

XXXII

extramedullary, II(2):4, 8, 10 hematogenous, II(I):57 hypothalamic/pituitary axis, 1(8):48 intracranial cystic-appearing posterior fossa lesion, 1(7):35, 39 foramen magnum mass, 1(4):42 irregular large ventricles, 1(3):54, 57 pineal + suprasellar lesions, 1(8):10 intraventricular choroid plexus lesions, 1(3):6, 7 foramen of Monro mass, 1(3):18, 20 fourth ventricle mass, 1(3):32-33 lateral ventricle mass, 1(3):12, 14 thick septum pellucidum, 1(3):16, 17 lower extremity pain, 11(1):48-49, 50 melanoma. See Melanoma, metastases meningeal. See Meningeal metastases midbrain lesion, 1(6):100, 102 osseous. See Osseous metastases, blastic; Osseous metastases, lytic osteoblastic, 1(1):12, 13 paraspinal muscle abnormalities, II(5):1O, 11 parenchymal. See Parenchymal metastases perineural CNV2, 1(10):23, 25 perineural CNV3, 1(10):22-23, 24 perivascular space enhancing lesions, 1(6):76 pituitary intrasellar lesion, 1(8):20 pituitary gland enlargement, 1(8):18 Tl isointense suprasellar mass, 1(8):54 pontine lesion, 1(7):6 quadrigeminal cistern mass, 1(8):8 sacral deformity, 11(1):26, 28 skull base. See a/so Skull metastases bilateral cavernous sinus lesions, 1(10):18, 20 Meckel cave lesion, 1(10):22, 24 spondylolisthesis, II(3):20 to stalk/pituitary, 1(8):46, 47 suprasellar mass, 1(8):25, 29, 42 vermis mass, 1(7):28, 30 vertebral body focal T1 hypointense signal, II(3):56, 57 ventral/lateral paraspinal mass, II(5):8 white matter lesion, solitary, 1(6):30, 32 Methanol toxicity, 1(6):84, 85 Methylmalonic acidemia, 1(6):87, 89 Micro-arteriovenous malformations, multiple, 1(5):82, 85 Microangiopathy mineralizing, 1(5):83, 1(9):10, 11 thrombotic, 1(5):51, 55, 102 Microcephaly, 1(1):38-42 thick skull, generalized, 1(1):8, 10 thin cortex, 1(6):15, 19 Microlissencephaly, 1(1):39, 43 Midbrain lesions, 1(6):100-103

Midline anomaly, 1(1):38, 42 Mineral deposition, 1(5):102, 103 Mineralization, 1(6):80, 82 Mitochondrial disorders bithalamic lesions, 1(6):93 encephalopathies, 1(6):81 medulla lesion, 1(7):11 midbrain cytopathy, 1(6):101, 103 pontine lesion, 1(7):7 Morphogenetic protein, bone, II(4):7, 9 Motor neuropathies, hereditary cauda equina enhancement, diffuse, II(6):2, 5 intradural lesion, serpentine, II(6):18, 19 Moyamoya arterial shape/configuration abnormalities, 1(9):3,5 FLAIRhyperintense CSF,1(4):65 perivascular space enhancing lesions (mimic), 1(6):77, 79 pial enhancement, 1(2):16, 19 MR artifacts flow-related arterial shape/configuration abnormalities, 1(9):2,4 cistern and subarachnoid space normal variants, 1(4):2, 3 FLAIRhyperintense CSF,1(4):64, 66 T1 hyperintense CSF,1(4):62 Tl hyperintense parenchymal lesions, 1(5):102, 104 T2 hypointense extra-axial lesions, 1(4):68, 69 third ventricle mass, general, 1(3):22, 23 magnetic susceptibility FLAIRhyperintense CSF,1(4):64, 66 T1 hyperintense CSF,1(4):62 T2 hypo intense extra-axial lesions, 1(4):68, 69 patient-related, 1(4):64, 66 Mucopolysaccharidoses adult back pain, II(I):52 CI-C2 instability, II(2):12 craniovertebral junction abnormalities, II(2):4 CSF-Iike parenchymal lesions, 1(5):23, 26 kyphosis, 11(1):12 macrocephaly, 1(1):33, 37 multiple brain hyperintensities (T2/FLAIR), 1(5):64, 67 myelopathy, II(7):48, 52 odontoid deformity, 11(2):14 perivascular spaces, enlarged, 1(6):74, 75 periventricular T2/FLAIR lesions, 1(3):73 platyspondyly, diffuse, 11(1):16 scoliosis, 11(1):10 vertebral anomalies, congenital, 11(3):2 vertebral body dysmorphic, II(3):10

INDEX fracture, II(3):29 scalloping or widened canal, 1l(3):18 vertebral endplate contour abnormality, II(4):1O, 11 Multi-infarct dementia asymmetric cerebral hemispheres, 1(6):2, 5 confluent white matter lesions, 1(6):34, 36 large ventricles, 1(3):45, 47 thin cortex, 1(6):15, 18 Multiple myeloma adult back pain, Il(I):53, 55 aggressive bony lesion, II(3):24, 26 craniovertebral junction abnormalities, Il(2):4, 7 extradural marrow signal, abnormal, II(5):26, 28 facet abnormality, non-traumatic, II(3):32 kyphosis, Il(I): 12 lower extremity pain, 11(1):48 odontoid deformity, II(2):14, 15 platyspondyly, diffuse, II(I):16 sacral mass, adult, II(I):18, 21 spondylolisthesis, II(3):20 vertebral body diffuse Tl hypointense signal, II(3):52, 54 enlarged, soap bubble expansion, II(3):38, 40 flattened, II(3):6, 8, 9 focal Tl hypointense signal, II(3):56 Multiple sclerosis bithalamic lesions, 1(6):92 cerebellar mass, 1(7):22, 25 cerebral aqueduct/periaqueductallesion, 1(3):28, 30 corpus callosum abnormal shape or configuration, 1(6):47, 50 holes, 1(6):52 lesion without mass effect, 1(6):54 splenium lesion, 1(6):58, 59 thin, 1(6):40, 42 cranial nerve enhancement, 1(4):46, 48 cystic mass, solitary, 1(5):17, 19 enlarged sulci, generalized, 1(4):9, 11 ependymal enhancement, 1(3):40, 41 ependymal/subependymallesions, 1(3):8, 10 hypothalamus lesion, 1(8):49, 51 intramedullary lesions, II(7):20, 21 large ventricles, 1(3):44, 46 medulla lesion, 1(7):10, 12 midbrain lesion, 1(6):100, 102 multiple brain hyperintensities (T2/FLAIR), 1(5):65, 68-69 multiple enhancing lesions, 1(5):2, 3 parenchymal lesions CSF-like, 1(5):22, 24 hypodense, 1(5):57, 59, 60 Tl hyperintense, 1(5):102, 104 Tl hypointense, T2 hyperintense, 1(5):90, 92 Tl/T2 hyperintense, 1(5):86, 88

periventricular enhancing lesions, 1(3):58, 59 periventricular T2/FLAIR lesions, 1(3):72, 74 pontine lesion, 1(7):6, 8 restricted diffusion, 1(5):99, 101 ring-enhancing lesions, multiple, 1(5):12, 14 small brainstem, 1(7):4, 5 spinal cord cauda equina syndrome, II(6):36 intramedullary lesions, multiple, 11(7):12 intramedullary lesions, no enhancement, II(7):18 intramedullary lesions, ring/peripheral enhancement, II(7):24 intramedullary lesions, solid enhancement, II(7):14, 16 intramedullary lesions, T2 hyperintense, Tl isointense, II(7):30, 31 intramedullary lesions, Tl hypointense, 11(7):28,29 intramedullary mass, Il(7):2 myelopathy, II(7):48, 50 small/atrophic, II(7):1O, 11 T2 hyperintense cord lesions, central, 11(7):44, 45-46 T2 hyperintense cord lesions, dorsal, II(7):40, 41 T2 hyperintense cord lesions, ventral, II(7):38 thalamic lesion, unilateral, 1(6):90 thin cortex, 1(6):14, 18 tumefactive, 1(6):56, 57 white matter lesions confluent, 1(6):34, 36 solitary, 1(6):30, 32 Multiple system atrophy cerebellar atrophy, 1(7):19, 21 enlarged sulci, generalized, 1(4):9 pontine lesion, 1(7):7, 9 putamen lesions, 1(6):84 small brainstem, 1(7):4, 5 Muscle de nervation, II(5):1O, 11 Muscular dystrophy congenital cystic-appearing posterior fossa lesion, 1(7):35, 39 small brainstem, 1(7):4 thick cortex, 1(6):9, 12 scoliosis, II(I):10 Myelin vacuolization, 1(5):64, 67 Myelination, normal, 1(5):64, 66 Myelitis. See also Acute transverse myelitis; Spinal cord myelitis radiation-induced, II(7):10 viral intramedullary lesions, diffuse/ill-defined enhancement, 11(7):20, 22 intramedullary lesions, T2 hyperintense, Tl isointense, 11(7):31, 33 XXXIII

INDEX >C GJ "'Cl

C

myelopathy, II(7):49, 53 T2 hyperintense cord lesions, central, Il(7):45, 47 T2 hyperintense cord lesions, ventral, II(7):38, 39 Myelocystocele, terminal conus abnormality, Il(7):7 sacral deformity, 1I(1):26-27 sacrococcygeal mass, pediatric, 1I(1):23, 24 Myelofibrosis diffuse T1 hypointense signal, vertebral body, 1I(3):53, 55 diffuse vertebral body sclerosis, II(3):44 extradural lesions, no enhancement, Il(5):14, 15 Myeloma multiple dural-based masses, 1(2):9, 11 multiple lucent skull lesions, 1(1):22, 25 sclerotic, Il(3):44 Myelomeningocele/myelocele congenital vertebral anomalies, II(3):2 conus abnormality, II(7):7 lumbar soft tissue mass, pediatric, II(5):42, 43 sacral deformity, II(I):26-27, 28 Myelopathy, 1I(7):48-53. See also Radiation injuries and necrosis, myelopathy Myoclonus epilepsy with ragged red fibers (MERRF),1(6):71, 73 Myxoma, metastatic atrial, 1(5):83 Myxopapillaryependymoma calcified, II(6):29, 32 sacrococcygeal mass, pediatric, II(I):23, 24 spinal cord adult back pain, II(I):52 cauda equina syndrome, II(6):36, 37 conus abnormality, II(7):6, 7 intradural/extramedullary lesions, solid enhancement, Il(6):14, 16 intradural lesion, serpentine, II(6):18, 19 intramedullary lesion, solid enhancement, II(7):14 leptomeningeal enhancement, II(6):8, 10 lower extremity pain, II(I):49, 51 pediatric back pain, II(I):57, 59 sacral deformity, II(I):26, 28

N Nasopharyngeal carcinoma craniovertebral junction abnormalities, II(2):4, 8-9,10 invading clivus, 1(4):33, 37 unilateral cavernous sinus mass, 1(10):14, 16 NBIA (neurodegeneration with brain iron accumulation), 1(6):87, 89 Neoplasms. See also specific histologic types and locations bilateral basal ganglia lesions, 1(6):80 clival, 1(4):33 XXXIV

corpus callosum splenium lesion, 1(6):58, 61 midbrain lesions, 1(6):100, 103 pontine lesion, malignant, 1(7):6, 9 posterior fossa, adult, 1(7):40-43 primary CNS, 1(4):16 "pulvinar sign" (mimic), 1(6):96, 97 with CSF seeding, 1(3):40, 42 Nerve roots, conjoined, II(6):12, 13 Nerve sheath tumors malignant, intradural/extramedullary, II(6):15, 17 malignant peripheral leptomeningeal enhancement, 11(6):9,11 paras pinal muscle abnormalities, II(5):10 multiple nonsyndromic, II(6):20 Neural foramen, enlarged, II(3):16-17 Neurenteric cyst cisterna magna mass, 1(4):39, 41 CPA mass, 1(4):25, 29, 31 craniovertebral junction soft tissue abnormalities, II(2):9 cystic mass, solitary, 1(5):17, 21 extra-axial mass, 1(4):52, 53, 77 extradural marrow signal, normal, 1l(5):23, 25 foramen magnum mass, 1(4):43, 45 infratentorial midline cyst, 1(7):15, 17 intradural/extramedullary lesions no enhancement, II(6):12, 13 ring/peripheral enhancement, II(6):22, 24 T2 hyperintense, T1 isointense, II(6):34 T1 hypointense, II(6):29, 31 intramedullary lesions, no enhancement, II(7):18 myelopathy, II(7):49 posterior fossa lesion, cystic-appearing, 1(7):35, 39 prepontine cistern mass, 1(4):33, 37 Neuritis, post-viral, 1(4):47 Neuroblastic tumor enlarged neural foramen, II(3):16, 17 extradural lesions, solid enhancement, II(5):16, 18 normal extradural marrow signal, II(5):22 paraspinal muscle abnormalities, 11(5):10 pediatric back pain, II(I):56-57 sacrococcygeal mass, pediatric, II(I):22, 24 Neuroblastoma metastatic in children over 1 year, 1(5):113, 117 "hair on end," 1(1):6, 7 solitary dural-based mass, 1(2):5, 7 ventral/lateral paraspinal mass, 11(5):8 Neurocutaneous melanosis in children over 1 year, 1(5):112 in newborn/infant, 1(5):107, 111 perivascular space enhancing lesions, 1(6):77, 79 pial enhancement, 1(2):17, 19

INDEX T1 hyperintense parenchymal lesions, 1(5):102 Neurocysticercosis basal ganglia calcification, 1(6):62, 63 cerebral aqueduct/periaqueductallesion, 1(3):28, 30 cyst with nodule, 1(5):28, 29 cystic mass CPA, 1(4):28, 30 solitary, 1(5):16, 18 effaced sulci, fotal, 1(4):16 extra-axial mass CSF-like, 1(4):52, 53 hypodense, 1(4):76, 78 foramen of Monro mass, 1(3):18, 20 fourth ventricle mass, 1(3):32, 34 infratentorial midline cyst, 1(7):14, 16 infundibular stalk, absent/thin, 1(8):44, 45 interhemispheric fissure cysts, 1(4):20, 22 intrasellar mass, cystic, 1(8):22, 23 intraventricular calcifications, 1(3):62, 64 intraventricular mass, "bubbly-appearing," 1(3):36,38 lateral ventricle, asymmetric, 1(3):51 lateral ventricle mass, 1(3):12, 14 Meckel cave lesion, 1(10):23 multiple brain hyperintensities (T2/FLAIR), 1(5):71, 73 multiple enhancing lesions, 1(5):2, 4 multiple hypointense foci on GRE/SWI, 1(5):82-83, 85 parenchymal calcifications multiple, 1(5):40, 41 solitary, 1(5):34, 35 parenchymal lesions CSF-like, 1(5):22, 24 T1 hypointense, T2 hyperintense, 1(5):90 periventricular calcifications, 1(3):66-67, 69 pineal region mass, 1(8):2-3, 4 posterior fossa lesion, cystic-appearing, 1(7):35, 39 prepontine cistern mass, 1(4):32-33, 35 quadrigeminal cistern mass, 1(8):8, 9 ring-enhancing lesions, 1(5):6, 9, 12, 14 sellar/juxtasellar calcification, 1(8):14, 16 sulcal/cisternal enhancement, 1(4):54, 56 suprasellar mass calcified, 1(8):40, 41 cystic, 1(8):36, 38 general, 1(8):24, 26 T1 hypointense, 1(8):58, 59 third ventricle mass body/posterior, 1(3):26, 27 general, 1(3):22, 24 Neurocytoma, central in children over 1 year, 1(5):113 foramen of Monro mass, 1(3):18-19, 21 fourth ventricle mass, 1(3):33

intraventricular calcifications, 1(3):63, 65 intraventricular mass, "bubbly-appearing," 1(3):36,38 lateral ventricle mass, 1(3):12, 14 Neurodegeneration with brain iron accumulation (NBIA), 1(6):87, 89 Neuroectodermal tumor, primitive. See PNET (primitive neuroectodermal tumor) Neuroepithelial tumor, dysembryoplastic. See DNET (dysembryoplastic neuroepithelial tumor) Neurofibroma epidural mass, 11(5):2-3, 5 extradural lesions solid enhancement, 11(5):16, 18 T2 hyperintense, T1 isointense, 11(5):36,39 T1 hypointense, 11(5):33, 35 extradural marrow signal, normal, 11(5):23 intradural/extramedullary lesions multiple, 11(6):20 solid enhancement, 11(6):14, 16 T2 hyperintense, Tl isointense, 11(6):34 leptomeningeal enhancement, 11(6):8,10 lower extremity pain, 11(1):49 Meckel cave lesion, 1(10):23 neural foramen, enlarged, 11(3):16 paraspinal muscle abnormalities, 11(5):10, 11 pedicle abnormality, 11(3):36 plexiform cranial nerve enhancement, 1(4):46, 48 lumbar soft tissue mass, pediatric, 11(5):42,44 sacrococcygeal mass, pediatric, 11(1):22,24 unilateral cavernous sinus mass, 1(10):15 sacral deformity, 11(1):26,28 scalp, 1(1):16 vertebral body scalloping or widened canal, 11(3):18 Neurofibromatosis type 1 (Nfl) basal ganglia bilateral lesions, 1(6):80, 82 T1 hyperintense, 1(6):66, 67 T2 hyperintense, 1(6):70, 72 cranial nerve enhancement, 1(4):46 craniovertebral junction abnormalities, 11(2):4, 9,11 extradural lesions, multiple, 11(5):12, 13 fusiform arterial enlargement, 1(9):6 globus pallidus lesions, 1(6):86, 88 intradural/extramedullary lesions, multiple, 11(6):20 kyphoscoliosis, child, 11(1):14 kyphosis, 11(1):12 leptomeningeal enhancement, 11(6):8 lucent skull lesions, multiple, 1(1):23 macrocephaly, 1(1):32, 36 multiple brain hyperintensities (T2/FLAIR), 1(5):64, 66 xxxv

INDEX ><

QJ

"'C

C

parenchymal lesions Tl hyperintense, 1(5):102, 105 Tl hypointense, T2 hyperintense, 1(5):91, 93 Tl/T2 hyperintense, 1(5):87 pontine lesion, 1(7):7 scalp mass, 1(1):4, 5 scoliosis, I1(I): 10 septum pellucidum, thick, 1(3):16, 17 tectal plate lesion, 1(6):98, 99 thalamic lesion, unilateral, 1(6):90, 91 Neurofibromatosis type 2 (NF2) cavernous sinus lesions, bilateral, 1(10):18, 20 in children over 1 year, 1(5):113, 116 choroid plexus lesions, 1(3):6 CPA-lAC mass, 1(4):24, 26 cranial nerve enhancement, 1(4):46, 48 dural-based masses, multiple, 1(2):8, 10 intradural/extramedullary lesions, multiple, I1(6):20 intraventricular calcifications, 1(3):62, 64 leptomeningeal enhancement, I1(6):8 Neurogenic arthropathy aggressive bony lesion, I1(3):25, 27 intervertebral disc endplate irregularity, I1(4):7, 9 T2 hyperintense, I1(4):14 Tl hypo intense, I1(4):12, 13 kyphosis, I1(1):12 lumbar bony trauma, I1(1):8, 9 posterior element fracture, I1(3):34 scoliosis, I1(1):1O soft tissue calcification, paraspinal, II(5):20, 21 vertebral body, dysmorphic, I1(3):10 vertebral body fracture, II(3):28, 31 vertebral end plate abnormalities, II(4):1O, 16 Neuroglia] cyst CSF-Iike parenchyma] lesions, 1(5):23, 26 cystic-appearing posterior fossa lesion, ](7):34, 38 solitary cystic mass, 1(5):17, 20-21 Neurohypophysis, ectopic suprasellar mass general, 1(8):24, 29 Tl hyperintense, 1(8):56, 57 thick infundibular stalk, 1(8):46, 47 Neuromyelitis optica intramedullary lesions diffuse/ill-defined enhancement, II(7):20, 22 solid enhancement, II(7):14-15, 16-17 T2 hyperintense, Tl isointense, I1(7):30, 31 subarachnoid space narrowing, I1(6):6, 7 Neuropathies CIDP. See Chronic inflammatory demyelinating polyneuropathy (CIDP) femora], I1(1):48 hypertrophic. See Hypertrophic neuropathy motor and sensory, hereditary

cauda equina enhancement, diffuse, I1(6):2, 5 intradural lesion, serpentine, II(6):18, 19 peripheral, 11(1):42-43, 45-46 radial, 11(1):42-43, 45 ulnar, I1(1):43, 46 Neurosarcoid cavernous sinus mass or lesions bilateral, 1(10):19, 21 unilateral, 1(10):15, 17 cranial nerve enhancement, 1(4):47, 49 dural-based masses, 1(2):4, 6, 8, 10 dural tail sign, 1(2):20, 21 effaced sulci, generalized, 1(4):12 ependymal enhancement, 1(3):41, 43 ependymal/subependymallesions, 1(3):9 epidural mass, brain, 1(4):4-5, 6 extra-axial lesions or mass, 1(4):69, 71, 74 falx lesions, 1(2):12, 13 hypothalamus lesion, 1(8):48, 50 intrasellar lesion, 1(8):20, 21 lateral ventricle mass, ](3):12, 15 lucent skull lesions, multiple, 1(1):23 Mecke] cave lesion, 1(10):23, 24 medulla lesion, 1(7):11 mu]tiple brain hyperintensities (T2/FLAIR), 1(5):76, 78 mu]tiple enhancing lesions, 1(5):3, 5 multiple hypointense foci on T2, 1(5):80, 81 parenchymal lesions multiple hyperdense, ](5):51, 55 solitary hyperdense, 1(5):45, 49 Tl hypointense, T2 hyperintense, 1(5):90 Tl/T2 isointense, 1(5):95 perivascular space enhancing lesions, 1(6):76, 77 pial enhancement, 1(2):16, 18 pituitary gland enlargement, 1(8):18, 19 pontine lesion, 1(7):7 prepontine cistern mass, 1(4):33, 36 sulcal/cisternal enhancement, 1(4):54, 56 suprasellar mass enhancing, 1(8):42, 43 genera], 1(8):24-25, 27 hyperdense, 1(8):52 Tl isointense, 1(8):54 thick dura or arachnoid, generalized, 1(2):14, 15 thick infundibular stalk, 1(8):46 third ventricle mass, general, 1(3):22, 24 Neurosarcoidosis, 1(1):19, 1(6):81 Neurosyphilis, 1(4):5, I1(7):41 Nitrous oxide misuse, 11(7):40 Nocardia infections, 1(5):80, 81 Nonmeningothelial tumors benign cavernous sinus lesions, bilateral, 1(10):19 dural-based mass, solitary, 1(2):5, 6 dural calcification, 1(2):2, 3 sellar/juxtasellar calcification, 1(8):15

INDEX malignant hyperdense extra-axial mass, 1(4):74 solitary dural-based mass, 1(2):5, 7 Nutrition status, 1(4):9

o Occipital bones, squamous, 1(1):16 Occipital condyle fracture, II(2):2, 3, 4 Ochronosis, II(4):7 Odontoid C2 fracture CI-C2 instability, II(2):12 cranio-cervical junction acute injury, 11(2):2 craniovertebral junction abnormalities, II(2):4-5 odontoid deformity, II(2):14 Odontoid deformity, II(2):14-15 Odontoid process, hypoplastic, 11(2):14, 15 Oligoastrocytoma, 1(6):31 Oligodendroglioma anaplastic, 1(5):45, 48, 1(6):24-25 cerebellar mass, 1(7):23, 27 in children over 1 year, 1(5):112 corpus callosum mass, 1(6):56, 57 cortical hyperintensity Tl/FLAIR, 1(6):24, 27 effaced sulci, focal, 1(4):16, 18 focal cortical mass, 1(6):20, 22 parenchymal calcification, solitary, 1(5):34, 36 parenchymal lesions, 1(5):56, 58,90 thin skull, localized, 1(1):16, 17 white matter lesion, solitary, 1(6):31, 33 Olivary degeneration, hypertrophic large brainstem, 1(7):2, 3 medulla lesion, 1(7):11, 13 Olivopontocerebellar degeneration multiple brain hyperintensities (T2/FLAIR), 1(5):77,79

small brainstem, 1(7):4, 5 Opportunistic infections, AIDS. See also HIV infections cranial nerve enhancement, 1(4):47, 49 cyst with nodule, 1(5):29, 31 ependymal enhancement, 1(3):40, 42 ependymal/subependymallesions, 1(3):9 multiple brain hyperintensities (T2/FLAIR), 1(5):71,74

multiple enhancing lesions, 1(5):2, 4 multiple hypodense parenchymal lesions, 1(5):60-61,

62

multiple parenchymal calcifications, 1(5):41 ring-enhancing lesions, multiple, 1(5):12, 14 sulcal/cisternal enhancement, 1(4):55 Optic nerve glioma, 1(4):46, 48 Optic nerve sheath, enlarged, 1(4):2, 3 Optic neuritis, 1(4):46 Os odontoideum C1-C2 instability, 11(2):12, 13 cervical abnormality, chronic post-traumatic, 11(1):2

cranio-cervical junction acute injury, 11(2):2, 3 craniovertebral junction abnormalities, II(2):5 odontoid deformity, 11(2):14 Osmotic demyelination syndrome basal ganglia, 1(6):71, 72, 81, 83 bithalamic lesions, 1(6):93 cortical enhancement, 1(6):28 large brainstem, 1(7):2, 3 multiple brain hyperintensities (T2/FLAlR), 1(5):71,74-75

parenchymal

lesions, multiple hypodense,

1(5):61

pontine lesion, 1(7):6, 9 putamen lesions, 1(6):84, 85 restricted diffusion, 1(5):99, 101 white matter lesion, solitary, 1(6):31, 33 Osseous metaplasia, 1(2):2, 3, 12 Osseous metastases, blastic abnormal extradural marrow signal, II(5):26 aggressive bony lesion, II(3):24, 25 extradural lesions, solid enhancement, 11(5):16, 17

kyphosis, 11(1):12 pedicle abnormality, 11(3):36, 37 thickened bony trabeculae, 11(3):46, 47 vertebral body diffuse sclerosis, 11(3):44 diffuse Tl hypointense signal, 11(3):52, 54 flattened, II(3):6, 8, 9 focal sclerosis, 11(3):42, 43 Osseous metastases, lytic abnormal extradural marrow signal, II(5):26 aggressive bony lesion, II(3):24, 25 cervical bony abnormality, post-traumatic, 11(1):4

extradural lesions, solid enhancement, II(5):16, 18 facet abnormality, non-traumatic, II(3):32, 33 kyphosis, 11(1):12 lumbar soft tissue mass, pediatric, 11(5):43 odontoid deformity, 1I(2):14 pedicle abnormality, II(3):36 platyspondyly, diffuse, 1I(1):16 posterior element enlarged, II(3):13, 14 fracture, II(3):34 sacral mass, adult, 11(1):18, 19 vertebral body dysmorphic, II(3): 10 enlarged, II(3):13, 14, 38 flattened, II(3):6, 7, 8 to vertebral body or pedicle, II(3):16, 17 Ossification heterotopic, II(5):20 ligamentum flavum extradural lesions, no enhancement, II(5):14 myelopathy, II(7):48

INDEX normal extradural

marrow signal, 11(5):23, 25 extradural

T2 hypointense, Tl hypointense lesion, 11(5):40, 41

longitudinal ligament. See Longitudinal ligament ossification Osteoarthritis, lI(2):5, 6 Osteoblastoma abnormal extradural marrow signal, lI(5):27, 29 back pain, adult, 11(1):52 enlarged vertebral body, soap bubble expansion, 11(3):38, 40

enlarged vertebral body/posterior lI(3): 13, 15 epidural mass, lI(5):2, 6 extradural lesion, T1 hypo intense, kyphoscoliosis, child, lI(I):14 lower extremity pain, lI(I):48 pedicle abnormality, lI(3):36 scoliosis, lI(I):10 spondylolisthesis, 11(3):20

element,

lI(5):32

Osteochondroma congenital vertebral anomalies, lI(3):2, 3 dysmorphic vertebral body, lI(3):10, 11 enlarged vertebral body/posterior element, lI(3): 13, 15

extradural lesions, no enhancement, 11(5):14, 15 myelopathy, 11(7):49, 53 odontoid deformity, lI(2):14 sellar/juxtasellar calcification, 1(8):14 thick skull, localized, 1(1): 12 Osteodystrophy, renal lumbar bony trauma, lI(I):8 thoracic bony trauma, lI(I):6 vertebral body, diffuse Tl hypointense signal, lI(3):53

vertebral body sclerosis, diffuse, lI(3):44, 45 Osteogenesis imperfecta kyphosis, lI(I): 12 platyspondyly, diffuse, lI(I): 16, 17 scoliosis, lI(I): 10, 11 thin skull, generalized, 1(1):14, 15 vertebral anomalies, congenital, lI(3):2 vertebral body dysmorphic, lI(3): 10 flattened, lI(3):8, 9 fracture, lI(3):29 vertebral endplate contour abnormality, lI(4):1O Osteoid osteoma adult back pain, lI(I):52 kyphoscoliosis, child, lI(I):14 lower extremity pain, lI(I):48 pediatric back pain, lI(1):57, 59 pedicle abnormality, 11(3):36 scoliosis, lI(I): 10, 11 vertebral body sclerosis, focal, lI(3):42, 43 Osteoma sclerotic skull lesions, 1(1):26 , 28, 30, 31

sellar/juxtasellar calcification, 1(8): 14 Osteomalacia, lI(2):4 Osteomyelitis CI-C2 cervical abnormality, chronic post-traumatic, lI(I):2

craniovertebral

junction abnormalities,

11(2):4, 7, 8, 10 instability, lI(2):12

chronic diffuse vertebral body sclerosis, lI(3):44, 45 focal vertebral body sclerosis, lI(3):42 thick skull, localized, 1(1):12 granulomatous abnormal extradural marrow signal, 11(5):26,

28 acute upper extremity pain or weakness, 11(1):43, 46

adult back pain, 11(1):53, 55 aggressive bony lesion, lI(3):24, 26 cervical bony fusion, lI(3):4 congenital vertebral anomalies, lI(3):2 kyphoscoliosis, child, lI(I):14, 15 kyphosis, lI(1):12, 13 neural foramen, enlarged, 11(3):16 pediatric back pain, lI(I):57 pedicle abnormality, lI(3):36, 37 soft tissue calcification, paraspinal, lI(5):20, 21

thoracic bony trauma, 11(1):6 vertebral body, dysmorphic, lI(3):10, 11 vertebral body, focal Tl hypo intense signal, 11(3):56

vertebral body fracture, lI(3):29 vertebral end plate contour abnormality, lI(4):10

lytic skull lesion, solitary, 1(1):19, 21 pyogenic abnormal extradural marrow signal, lI(5):26,

27 acute upper extremity pain or weakness, lI(I):43,

47

adult back pain, 11(1):53, 54 aggressive bony lesion, 11(3):24, 26 cervical bony abnormality, post-traumatic lower, lI(I):4 cervical bony fusion, lI(3):4, 5 kyphoscoliosis, child, lI(I):14, 15 kyphosis, lI(I): 12 lumbar bony trauma, lI(I):8 pediatric back pain, lI(I):57, 59 scoliosis, lI(I):10 spondylolisthesis, lI(3):21, 23 vertebral body, dysmorphic, lI(3):10 vertebral body, flattened, 11(3):6, 7 vertebral body, focal Tl hypointense signal, 11(3):56, 57

INDEX vertebral body fracture, I1(3):28, 31 vertebral endplate contour abnormality, 11(4):10 vertebral end plate signal abnormality, I1(4):16, 17 skull, 1(1):23, 26, 29 Osteopathia striata, 1(1):12, 30 Osteopetrosis "hair on end," 1(1):6 thick skull, generalized, 1(1):9, 11 thick skull, localized, 1(1):12 vertebral body, diffuse Tl hypointense signal, I1(3):53, 55 vertebral body sclerosis, diffuse, 11(3):44,45 Osteophytes disc contour abnormality, 11(4):2-3 endplate, I1(5):40, 41 extradural lesion, Tl hypointense, 11(5):32 facet, I1(5):40 intervertebral disc, T1 hypointense, I1(4):12, 13 Osteopoikilosis, 1(1):30 Osteoporosis lucent skull lesions, multiple, 1(1):22, 25 platyspondyly, diffuse, 11(1):16 thickened bony trabeculae, I1(3):46, 47 vertebral body diffuse T1 hyperintense signal, I1(3):48, 49 flattened, 11(3):6,8 Osteoradionecrosis, 1(1):23 Osteosarcoma abnormal extradural marrow signal, 11(5):27,29 adult back pain, 11(1):53,55 diffuse vertebral body sclerosis, 11(3):44 epidural mass, 11(5):2,7 extradural lesions, 11(5):17,32 lower extremity pain, 11(1):48 pedicle abnormality, 11(3):36 sacrococcygeal mass, pediatric, I1(1):23, 24 secondary, I1(1):19, 21 soft tissue calcification, paraspinal, I1(5):20, 21 spondylolisthesis, I1(3):20 telangiectatic, 11(3):39,41 thick skull, localized, 1(1):12

p Pachygyria-polymicrogyria asymmetric cerebral hemispheres, 1(6):3, 6 epilepsy, 1(5):118-119, 122 focal cortical mass, 1(6):21, 23 thick cortex, 1(6):8, 11 Pachymeningitis, hypertrophic, 1(2):12, 14, 15, 1(4):69 Paget disease craniovertebral junction abnormalities, 11(2):4 lytic skull lesion, solitary, 1(1):18, 20 posterior element, enlarged, I1(3):12, 14

sacral mass, adult, 11(1):18,21 sclerotic skull lesions, 1(1):26 , 28, 30, 31 thick skull, 1(1):8, 10, 12, 13 thickened bony trabeculae, I1(3):46, 47 thin skull, localized, 1(1):16, 17 vertebral body diffuse sclerosis, I1(3):44, 45 diffuse T1 hyperintense signal, 11(3):48,49 enlarged, I1(3):12, 14 focal T1 hyperintense signal, 11(3):50,51 Panencephalitis, subacute sclerosing, 1(5):77, 79, 1(6):35 Pantopaque extra-axial lesions, T2 hypointense, 1(4):69 fat-like lesions, 1(5):32 intradural/extramedullary lesions, T1 hyperintense, 11(6):26,27 T1 hyperintense CSF,1(4):62 Pantothenate kinase associated neurodegeneration (PKAN),1(6):81 Papilloma, choroid plexus. See Choroid plexus papilloma Paraganglioma conus abnormality, 11(7):6 craniovertebral junction abnormalities, 11(2):4,9 glomus jugulare, 1(7):41 intradural/extramedullary lesions, I1(6):15, 17, 34 intradural lesion, serpentine, I1(6):18 Paraneoplastic syndromes bithalamic lesions, 1(6):93, 95 cerebellar atrophy, 1(7):18, 20 multiple brain hyperintensities (T2/FLAIR), 1(5):76, 79 Paraparesis/paraplegia, I1(1):10, 12 Parasites basal ganglia calcification, 1(6):63 cyst with nodule, 1(5):29, 31 cystic mass, solitary, 1(5):17, 21 intramedullary lesions, 11(7):21 intraventricular mass, "bubbly-appearing," 1(3):36 multiple brain hyperintensities (T2/FLAIR), 1(5):71, 73 multiple enhancing lesions, 1(5):3, 5 parenchymal calcification, 1(5):35, 38 parenchymal lesions CSF-Iike, 1(5):23, 26 multiple hyperdense, 1(5):51, 55 ring-enhancing lesions, 1(5):7, 11, 13, 15 Paraspinal abscess acute back pain/radiculopathy, postoperative, 11(1):30,32 acute upper extremity pain or weakness, 11(1):43 lumbar soft tissue mass, pediatric, I1(5):43, 45 normal extradural marrow signal, 11(5):22,24 paraspinal muscle abnormalities, 11(5):10,11 XXXIX

INDEX ><

CIJ "'C C

xl

scoliosis, II(I):10 ventral/lateral paraspinal mass, II(5):8, 9 Paraspinal hematoma, II(5):22 Paraspinal mass, ventral/lateral, II(5):8-9 Paraspinal muscle abnormalities, II(5):10-11 Parenchymal metastases cerebellar mass, 1(7):22, 24 cerebral aqueduct/periaqueductallesion, 1(3):29 in children over 1 year, 1(5):113 cortical mass, focal, 1(6):20, 21 cyst with nodule, 1(5):28, 30 cystic mass, solitary, 1(5):16, 18 large brainstem, 1(7):2 multiple brain hyperintensities (T2/FLAIR), 1(5):65, 69 multiple enhancing lesions, 1(5):2, 3 multiple hypointense foci on GRE/SWI, 1(5):82, 84 multiple hypo intense foci on T2, 1(5):80 parenchymal calcifications, 1(5):35, 39, 41, 42 parenchymal lesions multiple hyperdense, 1(5):50, 52 multiple hypodense, 1(5):60, 62 solitary hyperdense, 1(5):44, 46 solitary hypodense, 1(5):56 Tl hyperintense, 1(5):102, 104 Tl hypointense, T2 hyperintense, 1(5):91, 92 Tl/T2 hyperintense, 1(5):87, 89 Tl/T2 isointense, 1(5):94-95,96 periventricular enhancing lesions, 1(3):58, 61 periventricular T2/FLAIR lesions, 1(3):72, 74 posterior fossa neoplasms, adult, 1(7):40, 42 ring-enhancing lesions, 1(5):6, 7, 12, 13 sulci, focal effaced, 1(4):16, 19 suprasellar mass, hyperdense, 1(8):52 Parietal foramina, 1(1):22, 24 Parietal thinning, 1(1):2, 3, 16 Parkinson disease enlarged sulci, generalized, 1(4):9 midbrain lesion, 1(6):101 putamen lesions, 1(6):84 Pediatric back pain, II(I):56-59 Pedicles abnormalities, 11(3):36-37 absent or hypoplastic, II(3):16, 36, 37 congenitally short, II(3):36 stress fracture, posterior element, II(3):34 Peridural fibrosis back pain/radiculopathy, postoperative acute, II(I):30, 32 chronic, II(I):36, 38 disc contour abnormality, II(4):2, 4 extradural lesions solid enhancement, II(5):16, 17 T2 hyperintense, Tl isointense, II(5):36, 38 Tl hypo intense, II(5):32, 34 normal extradural marrow signal, II(5):23, 25

Perineural root sleeve cysts extradural, normal marrow signal, II(5):23, 25 extradural lesions, no enhancement, 11(5):14 neural foramen, enlarged, 11(3):16, 17 pedicle abnormality, 11(3):36 Peripheral neuropathy, 11(1):42-43, 45-46 Perisylvian dysplasia, 1(5):118, 120 Perivascular space enhancing lesions, 1(6):76-79 Perivascular spaces, enlarged, 1(6):74-75 basal ganglia, bilateral lesions, 1(6):80, 81 cerebellar mass, 1(7):22, 24 cerebral aqueduct/periaqueductallesion, 1(3):28, 30 corpus callosum holes, 1(6):52, 53 lesion without mass effect, 1(6):54, 55 mass, 1(6):56, 57 splenium lesion, 1(6):59 cystic mass, solitary, 1(5):16, 17 infratentorial midline cyst, 1(7):15, 17 midbrain lesion, 1(6):100, 102 multiple brain hyper intensities (T2/FLAIR), 1(5):64,67 parenchymal lesions CSF-like, 1(5):22, 23 Tl hypointense, T2 hyperintense, 1(5):90, 91 posterior fossa lesion, cystic-appearing, 1(7):35, 39 suprasellar mass cystic, 1(8):37, 39 Tl hypointense, 1(8):58, 59 white matter lesions, 1(6):30, 31, 34, 39 Periventricular abscess, 1(3):58, 60 Periventricular calcifications, 1(3):66-71 Periventricular enhancing lesions, 1(3):58-61 Periventricular T2/FLAIR lesions, 1(3):72-75 Petro us apex asymmetric marrow fat-like lesions, 1(5):32, 33 skull normal variants, 1(1):2, 3 cholesterol granuloma, 1(5):32, 33 Phenytoin, chronic use cerebellar atrophy, 1(7):18, 20 thick skull, generalized, 1(1):8, 10 Pial enhancement, 1(2):16-19 Pineal cyst extra-axial mass CSF-like, 1(4):52, 53 hypodense, 1(4):76, 78 interhemispheric fissure cysts, 1(4):20,21 pineal gland mass, 1(8):6 pineal region mass, 1(8):2, 3 Pineal gland mass, 1(8):6-7 Pineal region, 1(8):2-59 hypothalamus lesion, 1(8):48-51 infundibular stalk, 1(8):44-45, 46-47 intrasellar lesion, 1(8):20-21

INDEX intrasellar mass, cystic, 1(8):22-23 pineal + suprasellar lesions, 1(8):10-11 pineal gland mass, 1(8):6-7 pineal region mass, 1(8):2-5 pituitary gland, enlarged, 1(8):18-19 quadrigeminal cistern mass, 1(8):8-9 sella/pituitary normal variants, 1(8):12-13 sellar/juxtasellar calcification, 1(8):14-17 suprasellar masses calcified, 1(8):40-41 cystic, 1(8):36-39 enhancing, 1(8):42-43 general, 1(8):24-29 hyperdense, 1(8):52-53 pediatric, 1(8):30-35 T1 hyperintense, 1(8):56-57 T1 hypointense, 1(8):58-59 T1 isointense, 1(8):54-55 Pineoblastoma in children over 1 year, 1(5):113, 116 in newborn/infant, 1(5):107, 111 pineal gland mass, 1(8):6, 7 Pineocytoma, 1(8):2, 4, 6, 7 Pituicytoma hypothalamus lesion, 1(8):49, 51 pituitary gland enlargement, 1(8):18 suprasellar mass, 1(8):25, 28, 54, 55 thick infundibular stalk, 1(8):46, 47 Pituitary abscess, 1(8):25 Pituitary apoplexy intrasellar mass, cystic, 1(8):22 suprasellar mass cystic, 1(8):37, 39 T1 hyperintense, 1(8):56 T1 hypointense, 1(8):58 Pituitary bright spot, 1(8):12 Pituitary gland. See also Pineal region "bright," 1(8):12, 13 ectopic, 1(8):49 enlarged, 1(8):18-19 normal variants, 1(8):12-13 Pituitary hyperplasia intrasellar lesion, 1(8):20 physiologic, 1(8):12, 30, 32 pituitary gland enlargement, 1(8):18, 19 suprasellar mass, 1(8):54 Pituitary macroadenoma cavernous sinus mass or lesions, 1(10):14, 15, 18, 19

giant invasive, 1(4):43 intrasellar lesion, 1(8):20 Meckel cave lesion, 1(10):23 mimics, 1(8):18, 19 pituitary gland enlargement, 1(8):18, 19 prepontine cistern mass, 1(4):32, 35 suprasellar mass calcified, 1(8):40

cystic, 1(8):37, 39 enhancing, 1(8):42 general, 1(8):24, 25 hyperdense, 1(8):52 pediatric, 1(8):31, 34 T1 hyperintense, 1(8):56 T1 hypo intense, 1(8):58 T1 isointense, 1(8):54 Pituitary metastases intrasellar lesion, 1(8):20 pituitary gland enlargement, 1(8):18 Tl isointense suprasellar mass, 1(8):54 Pituitary microadenoma dural tail sign, 1(2):20, 21 intrasellar lesion, 1(8):20 pituitary gland enlargement, 1(8):18 sellar/juxtasellar calcification, 1(8):15, 17 third ventricle mass, general, 1(3):23, 25 Pituitary stalk anomalies absent/thin infundibular stalk, 1(8):44, 45 suprasellar mass, pediatric, 1(8):31, 33 transection, 1(8):44, 46 PKAN (pantothenate kinase associated neurodegeneration),I(6):81 Plagiocephaly, 1(6):3, 6 Plasmacytoma, II(5):32 abnormal extradural marrow signal, II(5):26, 28 cavernous sinus lesions, bilateral, 1(10):19, 21 craniovertebral junction abnormalities, 11(2):4, 8,10 dural-based mass, 1(2):5 epidural mass, 1(4):5, 6, II(5):2, 6 extradural lesions multiple, II(5): 12 solid enhancement, II(5):16, 18 T2 hyperintense, T1 isointense, II(5):37 lytic skull lesion, 1(1):18, 20 neural foramen, enlarged, 11(3):16 skull base, 1(4):33, 36 thickened bony trabeculae, II(3):46, 47 vertebral body, flattened, II(3):6 Platyspondyly, diffuse, II(1):16-17 Plexitis, choroid plexus, 1(3):6, 7 PNET (primitive neuroectodermal tumor). See also Medulloblastoma, PNET-MB intradural/extramedullary lesions, II(6):15 midbrain lesion, 1(6):100 supratentorial, pediatric, 1(5):106,113,116 Pneumatocyst, vertebral, II(3):56 Pneumocephalus extra-axial mass or lesions hypodense, 1(4):76, 78 T2 hypointense, 1(4):68, 70 multiple hypointense foci on GRE/SWI, 1(5):82, 84 Pneumonectomy, II(l):10 xli

INDEX Poliomyelitis, 11(1):10 Polycythemia dural sinus, hyperdense, 1(10):26-27, 28 dural sinus lesion, 1(10):3, 7 hyperattenuating artery, 1(9):8, 9 Polymicrogyria. See Pachygyria-polymicrogyria Polymyositis, II(5):20 Polyneuropathy, chronic inflammatory demyelinating. See Chronic inflammatory demyelinating polyneuropathy (ClOP) Pontine lesion, 1(7):6-9 Pontocerebellar hypoplasia, 1(7):4 Porencephalic cyst CSF-like parenchymal lesions, 1(5):22, 24 irregular large ventricles, 1(3):54, 56 solitary cystic mass, 1(5):16, 18 Post-radiation changes. See Radiation injuries and necrosis; Radiation therapy Post-surgical state. See Postoperative state Post-transplant lymphoproliferative disorder, 1(5):80 Post-traumatic deformity cervical bony fusion, 11(3):4 congenital vertebral anomalies, 11(3):2 dysmorphic vertebral body, 11(3):10 Post-traumatic state, 11(4):14, 15, 16 Posterior column injury, cervical, 11(1):4,11(3):21,

23 Posterior elements, spine enlarged, 11(3):12-15 fractures, 11(3):34-35 incomplete fusion CI-C2 instability mimic, 11(2):12 congenital vertebral anomalies, 11(3):2 cranio-cervical junction acute injury, 11(2):2 fracture mimic, 11(1):4,8 post-traumatic bony abnormality, 11(1):4 posterior element fracture, 11(3):34, 35 lumbar bony trauma (fracture mimic), 11(1):8 Posterior fossa adult neoplasms, 1(7):40-43 cystic-appearing lesion, 1(7):34-39 pediatric neoplasms, 1(7):44-49 Posterior reversible encephalopathy syndrome (PRES),1(6):81. See also Hypertensive encephalopathy, acute Postoperative complications infection acute back pain/radiculopathy, postoperative, 11(1):30,31, 33, 35 chronic back pain/radiculopathy, postoperative, 11(1):37,41 kyphoscoliosis, child, 11(1):14 kyphosis, 11(1):12 spinal acute back pain/radiculopathy, postoperative, 11(1):30-31, 33-35 xlii

cauda equina syndrome, 11(6):36 cervical abnormality, chronic post-traumatic, 11(1):2 kyphoscoliosis, child, 11(1):14 lumbar bony trauma, 11(1):8 T1 hypointense disc, 11(4):12 vertebral endplate signal abnormality, 11(4):16 Postoperative state corpus callosum holes, 1(6):52 epidural fluid, effusion, fat, or air, 1(4):76, 78 normal change cervical abnormality, chronic post-traumatic, 11(1):2,3 cervical bony fusion, 11(3):4,5 congenital vertebral anomalies, 11(3):2,3 extradural lesion, Tl hypo intense, 11(5):32 intradural/extramedullary lesions, 11(6):32 lower cervical bony abnormality, posttraumatic, 11(1):4 lumbar bony trauma, 11(1):8 soft tissue calcification, paraspinal, 11(5):20 T2 hyperintense disc, 11(4):14, 15 Prematurity small brainstem, 1(7):4 thin corpus callosum, 1(6):40, 43 thin cortex, 1(6):14, 16 Prepontine cistern mass, 1(4):32-37 Presacral abscess, 11(1):22,23 Prevertebral abscess, 11(1):14 Primitive neuroectodermal tumor. See PNET (primitive neuroectodermal tumor) Primordial dwarfism, 1(1):14 Progeroid syndromes, 1(1):39, 43 Progressive multifocalleukoencephalopathy (PML) confluent white matter lesions, 1(6):34 corpus callosum lesion without mass effect, 1(6):54, 55 corpus callosum splenium lesion, 1(6):59, 61 medulla lesion, 1(7):11, 13 midbrain lesion, 1(6):101, 103 multiple brain hyperintensities (T2/FLAIR), 1(5):71, 74 pontine lesion, 1(7):6 Progressive supranuclear palsy midbrain lesion, 1(6):101 small brainstem, 1(7):4, 5 tecta I plate lesion, 1(6):98, 99 Proteus syndrome, 1(6):3, 7, 11(1):10 Pseudo-thick cortex. See Hypomyelination Pseudo-TORCH microcephaly, 1(1):39, 43 multiple parenchymal calcifications, 1(5):41, 43 periventricular calcifications, 1(3):67, 71 Pseudoaneurysm arterial shape/configuration abnormalities, 1(9):3,5 dissecting, 1(9):6, 7

INDEX extra-axial flow voids, 1(4):60 hyperattenuating artery, 1(9):8 Pseudoarthrosis T2 hyperintense disc, 11(4):14 T1 hypointense intervertebral disc, 11(4):12, 13 vertebral endplate signal abnormality, 11(4):16 Pseudo hypoparathyroidism basal ganglia calcification, 1(6):62 dural calcification, 1(2):2 multiple parenchymal calcifications, 1(5):40 T1 hyperintense basal ganglia, 1(6):67 Pseudomeningocele epidural mass, 11(5):2,4 extradural lesions, 11(5):14, 15,32,34 lumbar soft tissue mass, pediatric, 11(5):43,45 paraspinal muscle abnormalities, 11(5):10, 11 post-traumatic enlarged neural foramen, 11(3):16, 17 intradural/extramedullary lesions, 11(6):29, 31 Pseudoneoplasm, calcifying, 1(2):4 Pseudopseudohypoparathyroidism, 1(6):67 Pseudosubluxation C2-3, 11(2):2 pediatric C1-C2 instability, 11(2):12 spondylolysis, 11(3):20,21 Pseudotumor intracranial bilateral cavernous sinus lesions, 1(10):19, 21 CPA mass, 1(4):25, 27 Meckel cave lesion, 1(10):23, 25 pituitary gland enlargement, 1(8):18 solitary dural-based mass, 1(2):5, 7 thick dura or arachnoid, generalized, 1(2):14 unilateral cavernous sinus mass, 1(10):15, 17 retro-odontoid, 11(2):8,9 "Pulvinar sign," 1(6):96-97 Putamen lesions, 1(6):84-85 Pycnodystosis, 1(1):8 Pyogenic abscess, 1(7):6

Q Quadrigeminal cistern mass, 1(8):8 Quadrigeminal plate lesions, 1(6):98-99

R Rabies, [[(6):2 Radial neuropathy, 11(1):42-43, 45 Radiation and chemotherapy. See also Radiation therapy basal ganglia calcification, 1(6):63, 65 cerebellar atrophy, 1(7):18, 20 confluent white matter lesions, 1(6):34, 37 corpus callosum, abnormal shape or

configuration, 1(6):47, 50 enlarged sulci, generalized, 1(4):9, 11 large ventricles, 1(3):44-45, 46 multiple brain hyperintensities (T2/FLAIR), 1(5):65, 69 multiple hypointense foci on GRE/SWI, 1(5):83 nerve, post-procedure, 11(6):14 parenchymal calcifications, 1(5):41, 43 parenchymal lesions, 1(5):90 periventricular calcifications, 1(3):67, 70-71 periventricular T2/FLAIR lesions, 1(3):72, 74 ring-enhancing lesions, multiple, 1(5):13, 15 Radiation injuries and necrosis diffuse vertebral body sclerosis, 11(3):44 dysmorphic vertebral body, 11(3):10 myelopathy intramedullary lesions, diffuse/ill-defined enhancement, 11(7):21,23 subarachnoid space narrowing, 11(6):6 T2 hyperintense cord lesions, central, 11(7):45,47 pontine lesion, 1(7):7 ring-enhancing lesion, solitary, 1(5):6 Radiation therapy kyphoscoliosis, child, 11(1):14 post-procedure changes, 11(3):10 spinal, in childhood congenital vertebral anomalies, 11(3):2 flattened vertebral body, multiple, 11(3):8 scoliosis, 11(1):10 Radiculomyelitis, viral, 11(6):2,5 Radiculopathy anterior radiculopathy syndrome, 11(6):9,II, 15 back pain, postoperative acute, 11(1):30-35 chronic, 11(1):36-41 cytomegalovirus- related cauda equina enhancement, diffuse, 11(6):3,4 intradural/extramedullary lesions, solid enhancement, 11(6):15, 17 Rasmussen encephalitis, 1(5):77, 79 Rathke cleft cyst extra-axial mass, 1(4):77, 79 intrasellar lesion, 1(8):20 intrasellar mass, cystic, 1(8):22, 23 sellar/juxtasellar calcification, 1(8):15 suprasellar mass cystic, 1(8):36, 38 general, 1(8):24, 27 hyperdense, 1(8):52, 53 pediatric, 1(8):31, 35 T1 hyperintense, 1(8):56, 57 T1 hypointense, 1(8):58 T1 isointense, 1(8):54, 55 Renal cell carcinoma, 11(3):38,40 Renal failure, chronic FLAIRhyperintense CSF,1(4):65, 67

=..,Q.

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xliii

INDEX >< Q,j "'C C

hyperdense CSF,1(4):72 vascular calcifications, 1(9):10 Retinoblastoma quadrilateral, 1(8):10, 11 trilateral pineal gland mass, 1(8):6, 7 suprasellar mass, pediatric, 1(8):31, 35 Retroperitoneal hematoma, 11(1):48 Rhabdomyolysis, 11(5):10, 11 Rhabdomyosarcoma, 11(1):23,24 Rheumatoid arthritis CI-C2 instability, 11(2):12, 13 cervical abnormality, chronic post-traumatic, 11(1):2,3 craniovertebral junction abnormalities, 11(2):5, 8, 9 facet abnormality, non-traumatic, 11(3):32,33 intervertebral disc endplate irregularity, 11(4):7, 8 lower cervical bony abnormality, posttraumatic, 11(1):4 odontoid deformity, 11(2):14 pannus from, 11(2):5,7 spondylolisthesis, 11(3):21 vertebral endplate signal abnormality, 11(4):16 Rhombencephalosynapsis (mimics), 1(7):29, 31 Rib anomalies hypoplastic or supernumerary rib, 11(3):34 scoliosis, 11(1):10, 11 Rickets craniovertebral junction abnormalities, 11(2):4 multiple hypodense parenchymal lesions, 1(5):61, 63 thin skull, generalized, 1(1):14 Rosai-Dorfman disease dural sinus lesion, 1(10):3 dural tail sign, 1(2):20 epidural mass, brain, 1(4):5 falx lesions, 1(2):12 multiple dural-based masses, 1(2):9, 11 solitary dural-based mass, 1(2):5, 7 Rotary subluxation, atlanto-axial CI-C2, 11(2):4,12 cranio-cervical junction acute injury, 11(2):2 Rubella, congenital, 1(3):66, 69

s Saccular aneurysm arterial shape/configuration abnormalities, 1(9):2, 4 atypical, 1(9):6, 7 cavernous sinus mass, unilateral, 1(10):14, 16 extra-axial flow voids, 1(4):60, 61 extra-axial lesions, 1(4):68, 71 intrasellar lesion, 1(8):20 parenchymal calcification, 1(5):35, 39 xliv

sellar/juxtasellar calcification, 1(8):14, 16 suprasellar mass calcified, 1(8):40, 41 cystic, 1(8):37, 39 enhancing, 1(8):42, 43 general, 1(8):24, 26 hyperdense, 1(8):52 pediatric, 1(8):31, 34-35 thrombosed acute, 1(8):58, 59 intra sellar mass, cystic, 1(8):22 suprasellar mass, 1(8):56, 57 vascular calcifications, 1(9):10, 11 Sacral deformity, 11(1):26-29 Sacral foraminal mass, 11(1):26 Sacral fractures traumatic, 11(1):26,28 zone 3, 11(6):36, 37 Sacral mass, adult, 11(1):18-21 Sarcoidosis cauda equina enhancement, diffuse, 11(6):3,4 cauda equina syndrome, 11(6):36 cord lesions, dorsal, 11(7):40-41, 43 CPA-lAC mass, 1(4):25, 26 intradural/extramedullary lesions, 11(6):14-15, 17,34 intramedullary lesions, 11(7):12, 13 intramedullary mass, 11(7):3,5 leptomeningeal enhancement, 11(6):9,11 Sarcoma primary CNS, pediatric, 1(5):112 scalp mass, 1(1):4 Scalp and skull, 1(1):2-43. See also Skull base; Skull metastases "hair on end," 1(1):6-7 lacunar skull Chiari 2, 1(1):23, 25 thin skull, generalized, 1(1):14, 15 macrocephaly, 1(1):32-37 microcephaly, 1(1):38-42 scalp mass or lesions, 1(1):4-5, 16 sclerotic skull lesions multiple, 1(1):30-31 solitary, 1(1):26-29 skull, normal variants, 1(1):2-3 lytic skull lesion, solitary, 1(1):18, 19 multiple lucent skull lesions, 1(1):22 thick skull, generalized, 1(1):8, 9 thin skull, localized, 1(1):16 skull lesions lucent, multiple, 1(1):22-25 lytic, solitary, 1(1):18-21 thick skull generalized, 1(1):8-11 localized, 1(1):12-13 thin skull generalized,I(I):14-15 localized,I(I):16-17

INDEX Scheuermann disease congenital vertebral anomalies, II(3):2 dysmorphic vertebral body, II(3):10, 11 intervertebral disc end plate irregularity, II(4):6, 8

kyphoscoliosis, child, 11(1):14,IS kyphosis, 11(1):12,II(3):8, 9 lumbar bony trauma, II(1):8 pediatric back pain, II(1):S6, S8 platyspondyly, diffuse, II(l): 16, 17 thoracic bony trauma, 1T(1):6,7 vertebral body fracture, II(3):29 vertebral endplate contour abnormality, II(4):1O, 11

Schistosomiasis, II(7):7 Schizencephaly asymmetric cerebral hemispheres, 1(6):3, 7 epilepsy, 1(5):118, 121 irregular large ventricles, 1(3):55, 57 Schmorl node adult back pain, 1T(1):53 aggressive bony lesion, II(3):25, 27 dysmorphic vertebral body, II(3):10 extradural lesions, no enhancement, 11(5):14 focal T1 hypointense signal, vertebral body, II(3):56 intervertebral disc endplate irregularity, II(4):6 lumbar bony trauma, II(1):8, 9 thoracic bony trauma, II(1):6 vertebral body fracture, II(3):28, 31 vertebral endplate contour abnormality, II(4):1O vertebral endplate signal abnormality, II(4):16, 17

Schwan noma cavernous sinus mass, unilateral, 1(10):14, 16 in children over 1 year, 1(5):113 craniovertebral junction abnormalities, II(2):4, 9 cystic cystic-appearing posterior fossa lesion, 1(7):35,38 extra-axial mass, CSF-Iike, 1(4):52 intradural/extramedullary lesions, II(6):22, 23,28,30 solitary cystic mass, 1(5):17, 21 dural tail sign, 1(2):20, 21 enlarged neural foramen, II(3):16 epidural mass, II(5):3, 5 extra-axial mass or lesions, 1(4):68, 70, 76 extradural lesions, II(5):16, 18, 36-37 extradural marrow signal, normal, II(5):23 facial nerve, CPA-lAC, 1(4):25,27 cystic mass, 1(4):29, 31 posterior fossa, adult, 1(7):41 foramen magnum mass, 1(4):42, 44 foraminal, II(4):3 hypoglossal nerve, 1(7):41

intradural/extramedullary lesions multiple, II(6):20 solid enhancement, II(6):14, 15 T2 hyperintense, T1 isointense, II(6):34 intradural lesion, serpentine, II(6):18 intramedullary mass, II(7):3, 5 intraparenchymal, 1(5):29, 31 jugular foramen CPA mass, adult, 1(4):25, 27 intramural CPA cystic mass, 1(4):29, 31 posterior fossa, adult, 1(7):41, 42 leptomeningeal enhancement, II(6):8, 10 lower extremity pain, II(1):49, 51 melanotic, 11(6):26,27 paraspinal muscle abnormalities, II(5):10 pedicle abnormality, II(3):36, 37 posterior fossa, pediatric, 1(7):44, 47 prepontine cistern mass, 1(4):33, 37 soft tissue calcification, paraspinal, II(5):20 trigeminal, intracranial, [(7):40, 1(10):22, 23 ventra[/Iateral paraspinal mass, 11(5):8,9 vertebral body scalloping or widened canal, 11(3):18,19 vestibular CPA-lAC mass, [(4):24, 25 posterior fossa neoplasms, adult, 1(7):40, 41 with arachnoid cyst, CPA cystic mass, [(4):29,

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I'D

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31 with intramural CPA cysts, 1(4):28, 30 Scleroderma, linear (coup de Sabre), 1(1):16 Scoliosis, 11(1):10-11 cervical abnormality, chronic post-traumatic, II(1):2 congenital, II(l):lO, 11 congenital vertebral anomalies, II(3):2 kyphoscoliosis, child, II(1):14 kyphosis, II(l): 12 lumbar bony trauma, II(1):8 myelopathy, 1T(7):48 pediatric back pain, II(1):56, 58 thoracic bony trauma, II(1):6, 7 vertebral body fracture, II(3):28, 31 degenerative, II(1):10, 37, 41 dysmorphic vertebral body, II(3):10 idiopathic, II(l):lO kyphoscoliosis, child, II(1):14 pediatric back pain, II(1):56, 57 lower cervical bony abnormality, posttraumatic, II(1):4 lumbar soft tissue mass, pediatric, II(5):42, 44 neuromuscular, 11(1):10,11 kyphoscoliosis, child, II(1):14, 15 kyphosis, II(l): 12 pediatric back pain, 11(1):56,57 traumatic, 11(1):10,11 vertebral body/posterior element, enlarged, 11(3):12,14 xlv

INDEX Sebaceous cyst, 1(1):4, 5 Sella turcica. See also Pineal region cystic intrasellar mass, 1(8):22-23 empty sella cystic intrasellar mass, 1(8):22 intrasellar lesion, 1(8):20 normal variant, 1(8):12, 13 intrasellar lesion, 1(8):20-21 J-shaped, 1(8):12 normal variants, 1(8):12-13 small, 1(8):12, 13 Sellar/juxta sellar calcification, 1(8):14-17 Sensory neuropathies, hereditary cauda equina enhancement, diffuse, 11(6):2,5 intradural lesion, serpentine, 11(6):18, 19 Septic emboli, 1(5):71, 73, 83 Septic facet joint arthritis, 11(3):32, 33 Septo-optic dysplasia absent/thin infundibular stalk, 1(8):44, 45 epilepsy, 1(5):118, 121 Septum pellucidum, thick, 1(3):16-17 Shear injury, 11(1):4 Sickle cell disease adult back pain, 11(1):53,55 "hair on end," 1(1):6,76 intervertebral disc endplate irregularity, 11(4):7, 9 lumbar bony trauma, 11(1):8,9 multiple brain hyperintensities (T2/FLAIR), 1(5):70,72 platyspondyly, diffuse, 11(1):16 thick skull, generalized, 1(1):8, 11 thoracic bony trauma, 11(1):6 vertebral anomalies, congenital, 11(3):2 vertebral body diffuse sclerosis, 11(3):44,45 diffuse T1 hypointense signal, 11(3):52-53, 55 dysmorphic, 11(3):10, 11 flattened, 11(3):8,9 fracture, 11(3):29 vertebral endplate contour abnormality, 11(4):10 Siderosis CNS, 1(8):20, 21 superficial effaced sulci, focal, 1(4):17 hyperdense CSF,1(4):72 intradural/extramedullary lesions, 11(6):32, 33 Sinus pericranii enlarged cortical veins, 1(10):8, 9 lytic skull lesion, solitary, 1(1):19, 21 scalp mass, 1(1):4 Skeletal hyperostosis, diffuse idiopathic (DISH) cervical bony fusion, 11(3):4,5 chronic post-traumatic cervical abnormality, 11(1):2 congenital vertebral anomalies, 11(3):2 xlvi

normal extradural marrow signal, 11(5):23 soft tissue calcification, paraspinal, 11(5):20 thoracic bony trauma, 11(1):6 Skull. See Scalp and skull Skull base chondrosarcoma, 1(4):33, 36, 43 metastases, 1(10):18, 20, 22, 24 plasmacytoma, 1(4):33, 36 Skull fracture, depressed, 1(10):3, 6 Skull metastases. See also Meningeal metastases "hair on end," 1(1):6 lytic skull lesion, solitary, 1(1):18, 20 multiple lucent skull lesions, 1(1):22, 24 scalp mass, 1(1):4, 5 sclerotic skull lesions, 1(1):26 , 27, 30 Solitary fibrous tumor, meningeal, 1(2):12 Solvent inhalation, 1(6):93 Spherocytosis, hereditary, 1(1):6 Spinal cord. See also Spinal cord terms below; specific disorders, spinal cord adhesions, 11(6):29, 31 cavernous malformation. See Cavernous malformation - spinal cord injuries, 11(2):2,11(7):10, 11 primary neoplasms, 11(7):6 small/atrophic, 11(7):10-11 T2 hyperintense lesions central, 11(7):44-47 dorsal, 11(7):40-43 ventral, 11(7):38-39 tethered cauda equina syndrome, 11(6):36 conus abnormality, 11(7):6,8 kyphoscoliosis, child, 11(1):14 lower extremity pain, 11(1):49 scoliosis, 11(1):10 Spinal cord abscess acute back pain/radiculopathy, postoperative, 11(1):31,35 intramedullary lesions diffuse/ill-defined enhancement, 11(7):20,23 ring/peripheral enhancement, 11(7):24,25 T2 hyperintense, T1 isointense, 11(7):31,33 T1 hypointense, 11(7):28,29 myelopathy, 11(7):49 Spinal cord astrocytoma conus abnormality, 11(7):6,8 intramedullary lesions no enhancement, 11(7):18, 19 ring/peripheral enhancement, 11(7):24 solid enhancement, 11(7):14, 16 T1 hyperintense, 11(7):34, 36 T2 hyperintense, T1 isointense, 11(7):30,32 T1 hypointense, 11(7):28, 29 intramedullary mass, 11(7):2,4 myelopathy, 11(7):48,50 subarachnoid space narrowing, 11(6):6,7

INDEX T2 hyperintense cord lesions, central, 11(7):45, 47 Spinal cord herniation intradural/extramedullary lesions, Tl hypointense, 11(6):28-29, 31 intradural lesion, serpentine, 11(6):18 myelopathy, 11(7):49 small/atrophic spinal cord, 11(7):10, 11 T2 hyperintense cord lesions, ventral, 11(7):38, 39 Spinal cord infarction acute back pain/radiculopathy, postoperative, 11(1):31, 35 chronic, small/atrophic spinal cord, 11(7):10, 11 conus abnormality, 11(7):7, 8 intramedullary lesions no enhancement, 11(7):18, 19 solid enhancement, 11(7):15, 17 T2 hyperintense, T1 isointense, 11(7):31, 33 intramedullary mass, 1I(7):3, 5 myelopathy, 1I(7):49, 53 T2 hyperintense cord lesions, central, 1I(7):44, 46 T2 hyperintense cord lesions, ventral, 11(7):38, 39 Spinal cord metastases conus abnormality, 11(7):7, 9 intramedullary lesions diffuse/ill-defined enhancement, 11(7):20, 23 multiple, 1I(7):12 ring/peripheral enhancement, 11(7):24, 25 solid enhancement, 1I(7):15, 17 T1 hyperintense, 11(7):34, 36 T2 hyperintense, T1 isointense, 11(7):31, 33 intramedullary mass, 11(7):3, 5 myelopathy, 11(7):49 subarachnoid space narrowing, 11(6):6 Spinal cord myelitis acute back pain/radiculopathy, postoperative, 11(1):31, 35 intramedullary lesions diffuse/ill-defined enhancement, 11(7):20, 23 ring/peripheral enhancement, 1I(7):24, 25 T2 hyperintense, T1 isointense, 11(7):31, 33 T1 hypointense, 11(7):28, 29 myelopathy, 11(7):49 Spinal cord syndrome, central myelopathy, 11(7):48, SO T2 hyperintense cord lesions, central, 1I(7):4S, 47 Spinal disorders, trans-spatial, 11(1):2-59 back pain adult, 11(1):52-55 pediatric, 11(1):56-59 back pain/radiculopathy, postoperative acute, 11(1):30-35 chronic, 1I(1):36-41

cervical chronic post-traumatic abnormality, 1I(1):2-3 lower, post-traumatic bony abnormality, 11(1):4-5 kyphoscoliosis, child, 1I(1):14-15 kyphosis, 11(1):12-13 lower extremity pain, 1I(1):48-51 lumbar bony trauma, II(I):8-9 platyspondyly, diffuse, II(I):16-17 sacral deformity, 1I(1):26-29 sacral mass, adult, II(I):18-21 sacrococcygeal mass, pediatric, 11(1):22-25 scoliosis, II(I):IO-11 thoracic bony trauma, 11(1):6-7 upper extremity pain or weakness, acute, II(I):42-47 Spinal dysgenesis, segmental, 11(7):6, 10 Spinal dysraphism, II(3):2 Spinal fractures, II(I):56 Spinal injuries, penetrating, 11(6):36 Spinal instability adult back pain, 11(1):52-53 chronic back pain/radiculopathy, postoperative, 11(1):36 post-treatment, II(3):20-21, 22-23 Spinal muscle injury adult back pain, II(I):52, 54 traumatic lumbar soft tissue mass, pediatric, II(5):42, 44 paraspinal muscle abnormalities, 11(5):10 pediatric back pain, 11(1):56 soft tissue calcification, paraspinal, 11(5):20 Spinal stenosis acquired adult back pain, II(I):52, 54 cervical, II(7):48, 51 subarachnoid space narrowing, 11(6):6 acquired, lumbar cauda equina syndrome, 11(6):36 extradural lesions, 1I(5):14 lower extremity pain, 11(1):48, SO central, 11(6):18, 19 compression, 1I(6):3, 5 congenital lower extremity pain, 1I(1):48, SO myelopathy, 11(7):48, 52 pediatric back pain, 1I(1):56, 58 subarachnoid space narrowing, 11(6):6 foraminal, lumbar, 11(1):48, SO Spinocerebellar ataxia, 1(7):4, II(7): 10 Spondylitis, ankylosing. See Ankylosing spondylitis Spondyloarthropathy hemodialysis aggressive bony lesion, 11(3):25, 27 soft tissue calcification, paraspinal, 11(5):20 vertebral endplate signal abnormality, 11(4):16, 17

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hemodialysis-related, 11(4):7, 9 seronegative C1-C2 instability, 11(2):12 cervical bony fusion, 11(3):4,5 congenital vertebral anomalies, 11(3):2,3 craniovertebral junction abnormalities, 11(2):4 kyphosis, 11(1):12 odontoid deformity, 11(2):14 post-traumatic lower cervical bony abnormality, 11(1):4 soft tissue calcification, paraspinal, 11(5):20, 21 T2 hyperintense disc, 11(4):14 Spondyloepiphyseal dysplasia C1-C2 instability, 11(2):12 congenital vertebral anomalies, 11(3):2 flattened vertebral body, multiple, 11(3):8,9 intervertebral disc endplate irregularity, 11(4):7, 9 myelopathy, 11(7):48, 53 odontoid deformity, 11(2):14 platyspondyly, diffuse, 11(1):16, 17 vertebral endplate contour abnormality, 11(4):10, 11

Spondylolisthesis, 11(3):20-23 cauda equina syndrome, 11(6):36, 37 dysplastic, 11(3):20, 21-22 lower extremity pain, 11(1):48, 50 myelopathy, 11(7):48 post-laminectomy, 11(1):36, 39 traumatic, 11(6):36 Spondylolysis adult back pain, 11(1):52, 54 enlarged vertebral body/posterior element, 11(3):12, 14 lower extremity pain, 11(1):48, 50 lumbar bony trauma, 11(1):8 pediatric back pain, II(1):56, 58 posterior element fracture, 11(3):34, 35 spondylolisthesis, 11(3):20, 22 Spondylotic myelopathy, 11(7):38, 39 Sprengel deformity, 11(1):10 Squamous bones, 1(1):16 Squamous cell carcinoma, 1(1):4 Status epilepticus corpus callosum splenium lesion, 1(6):58, 60 cortical enhancement, 1(6):28, 29 cortical hyperintensity Tl/FLAIR, 1(6):24, 26 effaced sulci, generalized, 1(4):13, 15 epilepsy, 1(5):119, 123 "pulvinar sign," 1(6):96 restricted diffusion, 1(5):99, 101 Steroids, 1(4):9, 11(3):6 Streak artifact, 1(4):72, 73 Stress fracture, sacral, 11(1):18, 19 Stress reactions, 11(3):36

Striatonigral degeneration, 1(7):4, 5 Sturge-Weber syndrome asymmetric cerebral hemispheres, 1(6):3, 6 choroid plexus lesions, 1(3):6, 7 enlarged deep veins, 1(10):10, 12 ependymal enhancement, 1(3):40 epilepsy, 1(5):119, 123 multiple parenchymal calcifications, 1(5):41, 42 pial enhancement, 1(2):16, 18 sulcal/Cisternal enhancement, 1(4):54, 57 Subacute combined degeneration, 1I(7):40, 42 Subarachnoid cisterns. See Extra-axial spaces and subarachnoid cisterns Subarachnoid hemorrhage aneurysmal effaced sulci, generalized, 1(4):12, 14 hyperdense CSF,1(4):72 sulcal/cisternal enhancement, 1(4):55 FLAIRhyperintense CSF,1(4):64, 65 intradural/extramedullary lesions, 11(6):12, 13, 26 large ventricles, 1(3):44, 46 nonaneurysmal perimesencephalic, 1(4):72, 73 Tl hyperintense CSF,1(4):62, 63 traumatic, 1(4):72 Subarachnoid space narrowing, 11(6):6-7 Subarachnoid spaces, enlarged benign, 1(4):9, 11 cistern and subarachnoid space normal variants, 1(4):2, 3 extra-axial fluid collection, CSF-Iike, 1(4):50 macrocephaly, 1(1):32, 35 Subdural abscess, 11(1):30, 11(7):48, 49 Subdural effusion, 1(4):50 Subdural hematoma acute falx lesions, 1(2):12 hyperdense dural sinus (mimic), 1(10):27, 29 hyperdense extra-axial mass, 1(4):74 acute back pain/radiculopathy, postoperative, TI(1):30-31,43 chronic calcified, 1(1):9, 11, 12, 13 dural calcification, 1(2):2, 3 extra-axial fluid collection, CSF-Iike, 1(4):50, 51 hypodense extra-axial masses, 1(4):76, 77 macrocephaly, 1(1):32, 35 multiple dural-based masses, 1(2):8, 10 thick dura or arachnoid, generalized, 1(2):14, 15

effaced sulci, focal, 1(4):16 intradural/extramedullary lesions, T1 hyperintense, TI(6):26, 27 lower extremity pain, 1I(1):49, 51 mixed, 1(4):68, 71 myelopathy, 11(7):48, 51 subacute, 1(4):12, 14

INDEX Subdural hygroma, 1(4):50 Subependymallesions, 1(3):8-11 Subependymal veins (mimic), 1(3):59 Subependymoma "bubbly-appearing" intraventricular

mass,

1(3):36,38

cisterna magna mass, 1(4):39,41 foramen magnum mass, 1(4):42, 45 foramen of Monro mass, 1(3):18, 21 fourth ventricle mass, 1(3):32, 34 intraventricular calcifications, 1(3):63, 65 lateral ventricle mass, 1(3): 12, 15 posterior fossa neoplasms, adult, 1(7):41, 42 Subgaleal hematoma, 1(1):4 Sulcal/cisternal enhancement, 1(4):54-57 Sulci effaced, focal, 1(4):16-19 enlarged, generalized, 1(4):8-11 Suprapineal recess, dilated, 1(3):26 Suprascapular nerve entrapment, 11(1):43, 46 Suprasellar mass calcified, 1(8):40-41 cystic, 1(8):36-39 enhancing, 1(8):42-43 general, 1(8):24-29 pediatric, 1(8):30-35 Supratentorial brain parenchyma, 1(6):2-103 asymmetric cerebral hemispheres, 1(6):2-7 basal ganglia bilateral lesions, 1(6):80-83 calcification, 1(6):62-65 TI hyperintense, 1(6):66-69 T2 hyperintense, 1(6):70-73 bithalamic lesions, 1(6):92-95 corpus callosum abnormal shape or configuration, 1(6):46-51 holes in, 1(6):52-53 lesion without mass effect, 1(6):54-55 masses, 1(6):56-57 splenium lesion, 1(6):58-61 thin, 1(6):40-45 cortical enhancement, 1(6):28-29 cortical hyperintensity TI/FLAIR, 1(6):24-27 focal cortical mass, 1(6):20-23 globus pallidus lesions, 1(6):86-89 midbrain lesion, 1(6):100-103 perivascular space enhancing lesions, 1(6):76-79 perivascular spaces, enlarged, 1(6):74-75 "pulvinar sign," 1(6):96-97 putamen lesions, 1(6):84-85 tecta I (quadrigeminal plate) lesion, 1(6):98-99 thick cortex, 1(6):8-13 thin cortex, 1(6):14-19 unilateral thalamic lesion, 1(6):90-91 white matter lesions confluent, 1(6):34-39 solitary, 1(6):30-33

Surgical defects asymmetric lateral ventricles, 1(3):50, 52 calvarial, 1(1):18, 22, 24 irregular large ventricles, 1(3):54, 55 Susac syndrome corpus callosum holes, 1(6):52, 53 corpus callosum lesion without mass effect, 1(6):54, 55

multiple brain hyperintensities

(T2/FLAIR),

1(5):71, 75

multiple enhancing lesions, 1(5):3, 5 parenchymal lesions, 1(5):90, 92 periventricular enhancing lesions, 1(3):58, 61 periventricular T2/FLAIR lesions, 1(3):73, 75 thin corpus callosum, 1(6):41, 44 Sutures, accessory, 1(1):2 Synovial cyst craniovertebral junction soft tissue abnormalities, 11(2):9 epidural mass, 11(5):2, 4 extradural lesions, 11(5):36, 38 facet joint extradural lesions, no enhancement, 11(5):14 lower extremity pain, I1(1):49, 51 non-traumatic facet abnormality, 11(3):32 normal extradural marrow signal, 11(5):22, 24 TI hypointense extradural lesion, 11(5):32, 34 Syphilis, acquired, 1(1):23 Syringobulbia cystic-appearing posterior fossa lesion, 1(7):35, 37 large brainstem, 1(7):2 medulla lesion, 1(7):11, 13 Syringomyelia acute upper extremity pain or weakness, 11(1):42, 45

conus abnormality, 11(7):6, 8 craniovertebral junction abnormalities, I1(2):4, 9 foramen magnum mass, 1(4):43, 45 intramedullary mass or lesions, I1(7):3, 18, 28 kyphoscoliosis, child, 11(1):14 myelopathy, 11(7):48, 50 pediatric back pain, 11(1):56, 58 subarachnoid space narrowing, 11(6):6 T2 hyperintense cord lesions, central, 11(7):44, 45

Syrinx collapsed, 11(7):10, 11 post-traumatic, I1(7):48, 51 Systemic lupus erythematosus basal ganglia, T2 hyperintense, 1(6):70, 72 corpus callosum splenium lesion, 1(6):59 fusiform arterial enlargement, 1(9):6 multiple hypodense parenchymal lesions, (5):61, 63

xlix

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T Taylor cortical dysplasia, 1(5):118, 122,1(6):8, 10 Tectal plate lesions, 1(6):98-99 Telangiectasia ataxia, 1(7):19 capillary enlarged deep veins, 1(10):11, 13 parenchymal lesions, 1(5):94, 96 pontine lesion, 1(7):6 radiation-induced, 1(5):83, 85 Temporal bone, squamous, 1(1):16 Tendinitis. See Calcific tendinitis, longus coli Teratoid-rhabdoid tumor, atypical in children over 1 year, 1(5):113, 117 fourth ventricle mass, 1(3):33, 35 in newborn/infant, 1(5):107, 110 posterior fossa lesion, cystic-appearing, 1(7):35, 39 posterior fossa neoplasm, pediatric, 1(7):45, 48 vermis mass, 1(7):29, 31 Teratoma fat in sulci/cisterns/ventricles, 1(4):58, 59 lateral ventricle mass, 1(3):13, 15 macrocephaly, 1(1):32, 35 parenchyma, fat-like lesions, 1(5):32, 33 pediatric in children over 1 year, 1(5):113, 116 in newborn/infant, 1(5):106, 108 suprasellar mass, 1(8):31, 33 pineal gland mass, 1(8):6, 7 sacrococcygeal normal extradural marrow signal, 11(5):23,25 sacral deformity, 11(1):27, 29 sacrococcygeal mass, pediatric, 11(1):22,23 Thalamic infarct, 1(6):96, 97 Thalamic lesions bithalamic, 1(6):92-95 unilateral, 1(6):90-91 Thalassemia adult back pain, 11(1):52 "hair on end," 1(1):6 thick skull, generalized, 1(1):9, 11 Thanatophoric dwarfism dysmorphic vertebral body, 11(3):10 platyspondyly, diffuse, 11(1):16, 17 vertebral anomalies, congenital, 11(3):2 vertebral endplate contour abnormality, 11(4):10 Third ventricle body/posterior mass, 1(3):26-27 dilated, 1(8):24, 26, 58 enlarged, 1(8):36 mass, general, 1(3):22-25 Thoracic spine. See also Chance fracture, thoracic acute back pain/radiculopathy, postoperative, 11(1):30,32 bony trauma, 11(1):6-7

compression fractures anterior, 11(1):6,12, 13, 11(3):28 lateral, 11(1):6,10, 14, 11(3):28 disc herniation, 11(5):22,11(7):48 distraction fracture, low, 11(1):6,11(3):28,30 Thoracolumbar junction fracture-dislocation 11(1):6,7 ' Thrombocolumbar fracture, burst, 11(1):14 Thrombolysis complications, 1(5):51, 55 Thrombophlebitis, 1(10):3, 7 Thrombosis. See also Cerebral venous thrombosis deep , cortical veins effaced sulci, focal, 1(4):17, 19 hyperdense extra-axial mass, 1(4):74 multiple brain hyperintensities (T2/FLAIR), 1(5):70, 72 deep venous, 1(5):70, 72 dural sinus effaced sulci, generalized, 1(4):12-13, 15 extra-axial flow voids, 1(4):60 hyperdense extra-axial mass, 1(4):74, 75 microangiopathies, 1(5):51, 55, 102 Thyroid carcinoma, 11(3):38,39 Tonsillar ectopia, 1(7):32 Tonsillar herniation, acquired, 1(4):42, 43 TORCH infections. See also Pseudo-TORCH ependymal/subependymallesions, 1(3):9, 11 intraventricular calcification (mimic), 1(3):63 microcephaly, 1(1):38, 40 parenchymal calcifications, 1(5):35, 39, 41, 42 periventricular calcification, 1(3):66 periventricular T2/FLAIR lesions, 1(3):73 Torticollis, 11(2):2 Toxic exposure basal ganglia lesions, bilateral, 1(6):80, 83 bithalamic lesions, 1(6):93 cord lesions, ventral, 11(7):38 epilepsy, 1(5):118 Toxoplasmosis acquired basal ganglia calcification, 1(6):62-63, 65 multiple hypointense foci on T2, 1(5):80, 81 periventricular enhancing lesions, 1(3):58, 60 ring-enhancing lesion, solitary, 1(5):6 basal ganglia lesions, bilateral, 1(6):81 congenital, 1(3):66, 68 cyst with nodule, 1(5):29, 31 Transient metabolic derangement, 1(6):58, 60 Transtentorial herniation, ascending, 1(8):8, 9 Transverse process fractures, 11(1):8,11(3):34,35 Trauma bilateral basal ganglia lesions, 1(6):80, 82 cervical abnormality, chronic post-traumatic (mimics), 11(1):2 enlarged sulci, generalized, 1(4):9, 10 microcephaly, non accidental, 1(1):38, 40

INDEX pedicle abnormality, II(3):36 post-traumatic deformity cervical bony fusion, II(3):4 congenital vertebral anomalies, 1I(3):2 dysmorphic vertebral body, II(3):10 post-traumatic state, II(4):14, 15, 16 Trisomy 21, II(2):5, 6, 12 Tuber cinereum hamartoma hypothalamus lesion, 1(8):49, 51 parenchymal lesions, 1(5):95, 97 suprasellar mass general, 1(8):25, 28 pediatric, 1(8):30, 32-33 Tl isointense, 1(8):54, 55 third ventricle mass, 1(3):23, 25 Tuberculoma acquired, 1(5):7, 10 conus abnormality, II(7):6 epidural mass, 1(4):5, 6 intradural/extramedullary lesions, II(6):34 intramedullary lesions, II(7):35 medulla lesion, 1(7):11, 13 multiple hypointense foci on GRE/SWI, 1(5):83 parenchymal lesions multiple hyperdense, 1(5):51, 54 solitary hyperdense, 1(5):45, 49 solitary hypodense, 1(5):57 pontine lesion, 1(7):6 suprasellar mass, 1(8):25, 29 Tuberculosis basal ganglia calcification, 1(6):63 cavernous sinus mass, unilateral, 1(10):15 cerebellar mass, 1(7):23, 26 dural-based masses, 1(2):4, 6, 9, 11 dural tail sign, 1(2):20, 21 ependymal enhancement, 1(3):40, 43 extra-axial mass, hyperdense, 1(4):74 lytic skull lesion, 1(1):18 meningitis, 1(4):54, 56 multiple enhancing lesions, 1(5):2-3, 4 multiple hypointense foci on T2, 1(5):80, 81 parenchymal calcifications, 1(5):34, 36, 40, 41 parenchymal lesions, 1(5):61, 62 perivascular space enhancing lesions, 1(6):76, 78 periventricular calcifications, 1(3):67, 70 prepontine cistern mass, 1(4):33, 35 ring-enhancing lesions, 1(5):12, 14 spondylolisthesis, II(3):21 suprasellar mass calcified, 1(8):40 hyperdense, 1(8):52, 53 Tuberous sclerosis complex basal ganglia calcification (mimic), 1(6):63, 65 cortex, thick, 1(6):8, 10 cortical hyperintensity Tl/FLAIR, 1(6):25, 27 cortical mass, focal, [(6):20-21, 22 effaced sulci, focal, [(4):17

ependymal/subependymallesions, 1(3):8, 9 epilepsy, 1(5):118, 121 foramen of Monro mass, 1(3):18, 20 intraventricular calcifications, 1(3):62, 64 irregular large ventricles, 1(3):54, 56 macrocephaly, 1(1):32, 36 multiple brain hyperintensities (T2/FLAIR), [(5):71, 75 parenchymal calcifications, [(5):40-41, 42 parenchymal lesions multiple hyperdense, [(5):51, 54 multiple hypodense, 1(5):61, 63 solitary hyperdense, [(5):45, 49 Tl hyperintense, 1(5):102-103, 105 Tl hypointense, T2 hyperintense, 1(5):91, 93 Tl/T2 isointense, 1(5):95, 97 periventricular calcifications, 1(3):66, 69 Tuberous sclerosis hemimegalencephaly, 1(6):3, 6 Tumor-associated cysts, nonneoplastic, 1(6):74, 75 Tumoral calcinosis, familial, 1(2):2

U Ulnar neuropathy, 11(1):43,46 Upper extremity pain or weakness, acute, 11(1):42-

47 Uropathy, obstructive, II(I):52

V VACTERL,11(1):10,11(3):2 Vascular calcifications, 1(9):10-11 mimics, 1(6):63, 65 physiologic, 1(8):14,1(9):10 Vascular dementia, 1(4):8, 10 Vascular grooves, 1(1):2 Vascular lesions, pontine, 1(7):6, 8 Vascular malformation. See Arteriovenous malformation Vasculitis arterial shape/configuration abnormalities, 1(9):3,5 basal ganglia, 1(6):70 bithalamic lesions, 1(6):92-93 corpus callosum lesion without mass effect, 1(6):54 cortical enhancement, 1(6):28, 29 cortical hyperintensity Tl/FLAIR, 1(6):24, 26 ependymal enhancement, 1(3):41, 43 ependymal/subependymallesions, 1(3):9, 11 fusiform arterial enlargement, 1(9):6, 7 infectious, 1(6):70, 72 medulla lesion, 1(7):10 midbrain lesion, 1(6):101 multiple brain hyperintensities (T2/FLAIR), 1(5):70, 72 multiple enhancing lesions, 1(5):3, 5 Ii

INDEX ><

CI.I "'C

C

Iii

multiple hypointense foci on GRE/SWI, 1(5):83, 85 parenchymal lesions multiple hypodense, 1(5):61, 63 T1 hypointense, T2 hyperintense, 1(5):91, 93 perivascular space enhancing lesions, 1(6):76, 78 periventricular enhancing lesions, 1(3):58, 61 periventricular T2/FLAIRlesions, 1(3):72-73, 75 pial enhancement, 1(2):16, 18 pontine lesion, 1(7):7 Vasospasm, 1(9):3, 4 Vein of Galen malformation enlarged cortical veins, 1(10):8, 9 enlarged deep veins, 1(10):11 extra-axial flow voids, 1(4):60 pineal region mass, 1(8):3, 5 quadrigeminal cistern mass, 1(8):8, 9 Veins and venous sinuses, 1(10):2-29 cavernous sinus lesions, bilateral, 1(10):18-21 cavernous sinus mass, unilateral, 1(10):14-17 cortical veins, enlarged, 1(10):8-9 deep veins, enlarged, 1(10):10-13 dural sinus, hyperdense, 1(10):26-29 dural sinus lesions, 1(10):2-7 Meckel cave lesion, 1(10):22-25 normal,I(4):60 Vena cava (IVe) occlusion, !I(6):18, 19 Venolymphatic malformations, 1(1):4 Venous anomaly, developmental. See Developmental venous anomaly Venous congestion, subependymal, 1(3):40 Venous infarction, 1(6):20, 22, 81 Venous ischemia, 1(6):81, 92, 94 Venous lakes, 1(1):2, 22, 23 Venous thrombosis, 1(6):92, 94. See also Cortical veins, thrombosis Venous varix enlarged cortical veins, 1(10):8 extra-axial flow voids, 1(4):60 isolated,I(4):74 Ventricles and periventricular regions, 1(3):2-75 calcifications intraventricular, 1(3):62-65 periventricular, 1(3):66-71 cerebral aqueduct/periaqueductallesion, 1(3):28-31 choroid plexus lesions, 1(3):6-7 ependymal enhancement, 1(3):40-43 ependymal/subependymallesions, 1(3):8-11 foramen of Monro mass, 1(3):18-21 fourth ventricle masses, 1(3):32-35 open inferior (Blake pouch remnant), 1(3):3, 5 "trapped," 1(3):33, 35 intraventricular mass, "bubbly-appearing," 1(3):36-39

large ventricles, 1(3):44-47 lateral ventricles asymmetric, 1(3):50-53 irregular, 1(3):54-57 mass in, 1(3):12-15 normal variant, 1(3):50, 51 normal variants, 1(3):2-5, 48 periventricular enhancing lesions, 1(3):58-61 periventricular T2/FLAIRlesions, 1(3):72-75 septum pellucidum, thick, 1(3):16-17 small ventricles, 1(3):48-49 third ventricle mass body/posterior, 1(3):26-27 general, 1(3):22-25 Ventriculitis choroid plexus, 1(3):6, 7 chronic, 1(3):67, 70 ependymal enhancement, 1(3):40, 42 ependymallsubependymallesions, 1(3):8-9, 11 FLAIRhyperintense CSF,1(4):64, 67 hyperdense CSF,1(4):72 lateral ventricles, asymmetric, 1(3):50, 53 T1 hyperintense CSF,1(4):62, 63 Ventriculus terminalis, !I(7):7, 9 Vermian hypoplasia, congenital cerebellar atrophy (mimic), 1(7):19, 21 infratentorial midline cyst, 1(7):15, 17 Vermis mass, 1(7):28-31 Vertebral artery, !I(2):2, !I(3):16 Vertebral body, !I(3):2-57 accelerated degeneration, !I(3):24-25, 26 bony lesions, aggressive, !I(3):24-27 cervical bony fusion, !I(3):4-5 congenital anomalies, !I(3):2-3 dysmorphic, !I(3):1O-11 enlarged soap bubble expansion, !I(3):38-41 vertebral body or posterior element, !I(3):1215 facet abnormality, non-traumatic, !I(3):32-33 facet synovial cyst, !I(3):32 failure of formation. See Failure of vertebral formation flattened multiple, !I(3):8-9 solitary, !I(3):6-7 fractures posterior element, !I(3):34-35 vertebral body, !I(3):28-31 fusion, congenital enlarged vertebral body/posterior element, !I(3):13, 14 facet abnormality, non-traumatic, !I(3):32, 33 Tl hypointense intervertebral disc, !I(4):12 hypoplastic or absent pedicle, !I(3):16 neural foramen, enlarged, !I(3):16-17

INDEX normal variants diffuse T1 hyperintense signal, 11(3):48,49 diffuse T1 hypointense signal, 11(3):52,53 facet tropism, 11(3):32 focal T1 hyperintense signal, 11(3):50 scalloping or widened canal, 11(3):18 pedicle abnormality, 11(3):36-37 physiologic wedging, 11(1):6,7, 8 scalloping or widened canal, 11(3):18-19 sclerosis diffuse, 11(3):44-45 focal, 11(3):42-43 spondylolisthesis, 1T(3):20-23 T1 hyperintense signal diffuse, 11(3):48-49 focal, 11(3):50-51 T1 hypointense signal diffuse, 11(3):51-55 focal, 11(3):56-57 thickened bony trabeculae, 11(3):46-47 tumors, 11(3):21,23 Vertebral body sclerosis diffuse, 11(3):44-45 focal, 11(3):42-43 Vertebral duplication, partial cervical bony fusion, 11(3):4 congenital scoliosis or kyphosis, 11(1):10 congenital vertebral anomalies, 11(3):2 dysmorphic vertebral body, 11(3):10 extradural lesions, no enhancement, 11(5):14 kyphoscoliosis, child, 11(1):14 Vertebral endplate contour abnormality, 11(4):1011

Vertebral fractures. See also Fracture mimics cervical abnormality, chronic post-traumatic, 11(1):2 craniovertebral junction abnormalities, 11(2):4-5 focal T1 hypointense signal, 11(3):56, 57 healing, 11(3):44 pathologic acute upper extremity pain or weakness, 11(1):42,45 C1-C2 instability, 11(2):12 cranio-cervical junction acute injury, 11(2):2 flattened vertebral body, 11(3):6,8 kyphosis, 11(1):12 lower cervical bony abnormality, posttraumatic, 11(1):4,5 lumbar bony trauma, 11(1):8,9 myelopathy, 11(7):48 posterior element fracture, 11(3):34 scoliosis, 11(1):10 thoracic bony trauma, II(1):6 vertebral body, 11(3):28,30 posterior element, 11(3):34-35 traumatic, 11(3):8 vertebral body, 11(3):28-31 with epidural hematoma, 11(5):26,27

Vertebral segmentation failure cervical bony fusion, 11(3):4 congenital scoliosis or kyphosis, 11(1):12 congenital vertebral anomalies, 11(3):2 dysmorphic vertebral body, 11(3):10, 11 posterior element fracture, 11(3):34 vertebral body scalloping or widened canal, 11(3):18 Vertebrobasilar dolichoectasia foramen of Monro mass, 1(3):19, 21 third ventricle mass (mimic), 1(3):22, 24 Vertebrobasilar insufficiency, chronic, 1(7):18 Vertebroplasty focal vertebral body sclerosis, 11(3):42 postoperative back pain/radiculopathy, 11(1):31, 35,37 Vitamin B12 deficiency, spinal cord, 11(7):31,33, 49

w Wallerian degeneration medulla lesion, 1(7):10, 12 midbrain lesion, 1(6):100, 102 pontine lesion, 1(7):6 small brainstem, 1(7):4 spinal cord, 11(7):41,43 Wedge compression fracture, 11(4):16, 17 Wegener granulomatosis, brain multiple brain hyperintensities (T2/FLAIR), 1(5):76 perivascular space enhancing lesions, 1(6):77, 79 pial enhancement, 1(2):17 Wernicke encephalopathy bithalamic lesions, 1(6):93, 95 cerebral aqueduct/periaqueductallesion, 1(3):29, 31

hypothalamus lesion, 1(8):49, 51 midbrain lesion, 1(6):101, 103 restricted diffusion, 1(5):99 West Nile encephalitis, 1(5):76, 78 Whipple disease, 1(7):7 White matter confluent lesions, 1(6):34-39 decreased volume, 1(6):46 disease with lactate, 1(6):59 injury of prematurity, 1(6):40, 43 solitary lesions, 1(6):30-33 Wilson disease basal ganglia bilateral lesions, 1(6):81, 83 T1 hyperintense, 1(6):66, 69 T2 hyperintense, 1(6):71 bithalamic lesions, 1(6):93 cerebral aqueduct/periaqueductallesion,

1(3):29,

31 globus pallidus lesions, 1(6):87 Wormian bones, 1(1):2, 3 liii

INDEX ><

Q,j ""C

C

X Xanthoastrocytoma, pleomorphic in children over 1 year, 1(5):113, 116 cortical hyperintensity Tl/FLA1R, 1(6):25, 27 cyst with nodule, 1(5):28, 30 effaced sulci, focal, 1(4):16, 19 epilepsy, 1(5):119, 123 focal cortical mass, 1(6):20, 22 infratentorial midline cyst, 1(7):15 solitary cystic mass, 1(5):17, 20 Xanthogranuloma choroid plexus, 1(4):58, 59, 1(5):32 third ventricle mass, body/posterior, 1(3):26, 27

Z Zellweger syndrome, 1(6):34, 38

liv

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