Merrill's Atlas of Radiographic Positions & Radiologic Procedures, vol 2

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MERRILL'S ATLAS OF RADiOORAPHIC POSITIONS AND

ISBN (Set)

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(Volume II) 0-323-01607-3

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Printed in United States of America Last digit is the print number:

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0-323-0 1 604-9

(Volume Two) 0-323-01 607-3

RADIOLOOIC PROCEDURES. ED \ 0

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OUTUNE

I ntroduction Trauma radiography can be an excItIng and challenging environment for the radi­ ographer. For others, however, performing trauma procedures can be intimidating and stressful. The difference depends on how prepared the radiographer is to han­ dle the situation. To reduce the stress as­ sociated with trauma radiography, the ra­ diographer must be properly prepared for the multitude of responsibilities encoun­ tered in the emergency room (ER). The goals of this chapter are to ( I ) assist the radiographer to develop an understand­ ing of the imaging equipment utilized in trauma, (2) explain the role of the radiogra­ pher as a vital part of the ER team, and (3) pre ent the common radiographic proce­ dures performed on trauma patients. This chapter provides the information necessary to improve the skills and confidence of all radiographers caring for trauma patients.

Trauma i s defined as a sudden, unex­ pected, dramatic, forceful , or violent event. Trauma ranks as the leading cause of death in the United States for persons I to 34 years of age. This statistic excludes suic ide and homicide-related deaths. Trauma, homicide, and suicide rank first, second, and third, respectively, as the leading causes of death in persons age 1 5 to 24 years. Emergency medical care of­ ten is the difference between life and death when intentional or unintentional inj uries occur. Many types of facil ities provide emer­ gency medical care, ranging from major, metropol itan medical centers to small outpatient clinics in rural areas. The term trauma center signifies a specific level of e mergency medical care as defined by the American Col lege of S urgeons Commission on Trauma. Trauma centers are categorized into four levels of care. Level I is the most comprehensive and level IV the most basic . A level I center is usually a university-based center, re­ search faci l ity, or large medical center. It provides the most comprehensive emer­ gency medical care avai lable with com­ plete i maging capabilities 24 hours a day. All types of specialty physicians are available on site 24 hours a day. Radi­ ographers are also available 24 hours per

day. A l evel l/center probably has all of the same specialized care avai lable, but differs in that it is not a research or teach­ ing hospital and some specialty physi­ cians may not be avai lable on site . Level 11/ centers are usually located in smaller communities where level I or level I I care is not avai lable. I n general, level I I I centers do not have all specialists avail­ able, but are able to resuscitate, stabilize, asse , and prepare a patient for transfer to a larger trauma center. A level IV cen­ ter may not be a hospital at all, but rather a clinic or outpatient setting. These faci l ­ ities usually provide care for minor i n ­ juries, a s w e l l a s offer stabilization and arrange for tran fer of more serious in­ j uries to a larger trauma center. Several types of forces, including, blunt, penetrating, explosive, and heat, result in injuries. Examples of blunt trauma are motor vehicle accidents (MVA), which in­ cludes motorcycles accidents and colli­ sions with pedestrians; falls; and aggra­ vated assaults. Penetrating trauma includes gunshot wounds, stab wounds, impalement injuries, and foreign body ingestion or as­ piration. Explosive trauma causes injury by several mechanisms, including pressure shock waves, high velocity projectiles, and burns. B urns may be caused by a number of agents including fire, steam and hot wa­ ter, chemicals, electricity, and frostbite.

A

B

1 3- 1 A, Dedicated C-arm type trauma radiographic room with patient on the table. B, Dedicated conventional trauma radiographic room with vertical Bucky.

Fig.

(B, Courtesy of Fischer Imaging. Inc.) 2

Preliminary Considerations SPECIALIZED EQU IPMENT Time is a critical element in the care of a trauma patient. To minimize the time re­ quired to acquire diagnostic x-ray images, many ERs have dedicated radiographic equipment located in the department or im­ mediately adjacent to the department. Trauma radiographs must be taken with a mini mal of patient movement, requiring more maneuvering of the tube and image receptor (lR). Specialized trauma radio­ graphic systems are available and are de­ signed to provide greater flexibility in x-ray tube and I R maneuverability ( Fig. 1 3- 1 ). These specialized systems help to mini­ mize movement of the injured patient while performing i maging procedures. Additionally, some ERs are equipped with specialized beds or stretchers that have a moveable tray to hold the l R. This type of stretcher al lows the use of a mobile radio­ graphic unit and eliminates the require­ ment and risk of transferring an injured pa­ tient to the radiographic table.

Mobile radiography is widely utilized in the ER. Many patients will have in­ juries that prohibit transfer to a radio­ graphic table, or their condition may be too critical to interrupt treatment. Trauma radiographers must be competent in per­ formi ng mobi le radiography on almost any part of the body and be able to utilize accessory devices ( i .e., grids, air-gap tech­ nique) needed to produce quality mobile images. Mobile fluoroscopy units, usually re­ ferred to as C-arms because of their shape, are becoming more commonplace in ERs. C-arms are util ized for fracture reduction procedures, foreign body localization in limbs, and for reducing joint dislocations ( Fig. 1 3-2).

Positioning aids are a necessity in trauma radiography. Sponges, sandbags, and the creative use of tape are often the trauma radiographer's most useful tools. Most trauma patients are unable to hold the required positions as a result of pain or impaired consciousness. Other patients cannot be moved into the proper position because to do so would exacerbate their injury. Proper use of positioning aids as­ sist in quick adaptation of procedures to accommodate the patient 's condition. Grids and IR holders are necessities si nce many projections require the use of a horizontal central ray. I nspect grids rou­ tinely, because a damaged grid will often cause image artifacts. I R holders enable the radiographer to perform cross-table lateral projections (dorsal decubitus position) on numerous body parts with minimal distor­ tion. ER personnel should not hold the IR to prevent unnecessary exposure.

Fig. 1 3-2 A mobile fluoroscopic C-arm. (Courtesy of OEC Diasonics. Inc.)

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POSITIONING OF THE PATIENT EXPOSURE FACTORS Patient motion is always a consideration in The primary challenge of the trauma radi­ trauma radiography. The shortest possible ographer is to obtain a high quality, djag­ exposure time that can be set should be used nostic image on the first attempt when the in every procedure, except when a breathing patient is unable to move into the desired technique is desired. Unconscious patients position. Many methods are available to are not able to suspend respiration for the adapt a routine projectjon and obtain the exposure. Conscious patients are often in desired i mage of the anatomical part. To extreme pain and unable to c ooperate for the minjmize risk of exacerbating the patient's condition, the x-ray tube and lR should be procedure. Radiographic exposure factor compen­ positioned, rather than the patient or the sation may be required when making expo­ part. For example, position the stretcher sures through immobilization devices, like adjacent to the vertical Bucky or upright a spine board or backboard. Most trauma table as often as the patient's condition al­ patients arrive at the hospital with some lows (Fig. 1 3-4). This location enables ac­ type of immobilization device (Fig. 1 3-3). curate positionjng with mjnimal patient Pathologic changes should also be consid­ movement for cross-table lateral i mages ered when setting technical factors. For in­ (dorsal decubitus positions) on numerous stance, internal bleeding in the abdomjnal parts of the body. Addjtionally, the grid in cavity would absorb a greater amount of the table or vertical B ucky is usually a higher ratio than those used for mobile ra­ radiation than a bowel obstruction. diography, so i mage contrast is improved. Another technique to increase efficiency, while minimizing patient movement, is to take all of the AP projections of the re­ quested examinations, moving superiorly to inferiorly. Then perform all of the lat­ eral projections of the requested examina­ tjons, moving inferiorly to superiorly. This method moves the x-ray tube in the most expeditious manner.

A

B

Fig. 1 3-3 A, Typical backboard and neck brace used for trauma patients. B, BaCkboard. brace. and other re­ straints are used on the patient throughout transport. C, All restraints will remain with and on the patient until all x-ray examinations are completed.

4

c

When taking radiographs to localize a penetrating foreign object, such as metal or glass fragments or bullets, the entrance and/or exit wounds should be marked with a radiopaque marker that is visible on all projections (Fig. 1 3-5). Two exposures at right angles to each other will demon­ strate the depth, as well as the path, of the projectile.

Radiographer's Role as Part of the Trauma Team The role of the radiographer within the ER ultimately depends on the department proto­ col and staffing, as well as the extent of emergency care provided at the facility. Regardless of the size of the facility, the pri­ mary responsibilities of a radiographer in an emergency situation include the following: Perform quality diagnostic i maging procedures as requested Practice ethical radiation protection Provide competent patient care It is i mpossible to rank these responsi­ bil ities because they occur simultane­ ously, and all are vital to quality care in the ER. •

•

•

DIAGNOSTIC IMAGI NG PROCEDURES Producing a high quality, diagnostic im­ age is one of the more obvious roles of any radiographer. A radiographer in the trauma environment has the added respon­ sibility to perform that task efficiently. Efficiency and productivity are common and practical goals for the radiology de­ partment. In the ER, efficiency is often crucial to sav i ng the pat ient's l i fe. Diagnostic imaging in the ER is para­ mount to an accurate, timely, and often li fe-saving diagnosis.

Fig. 1 3-4 Stretcher positioned adjacent to vertical Bucky to expedite positioning. Note x-ray tube in position for lateral projections.

Fig. 1 3-5 Proper placement of radiopaque markers (inside red circles) on each side of a bullet entrance wound. The red circles are "stickies" that contain the radiopaque marker. 5

RADIATION PROTECTION One of the most essential duties and ethi­ cal re ponsibilities of the trauma radiogra­ pher is radiation protection of the patient, the members of the trauma team, and self. I n highly critical care situations, members of the trauma team cannot leave the pa­ tient while imaging procedures are being performed. The trauma radiographer must ensure the other team members are pro­ tected from unnecessary radiation expo­ sure. Common practices should mini­ mally incl ude the fol lowing: Clo e col l imation to the anatomy of in­ terest to reduce scatter Gonadal shielding for the patients of child-bearing age (when doing so does not interfere with the anatomy of interest) Lead aprons for al l personnel that re­ main in the room during the procedure Expo ure factors that minimize patient dose and scattered radiation Announcement of impending exposure to al low unnecessary personnel to exit the room Consideration must also be given to pa­ tients on nearby stretchers. I f there is less than 6 feet of distance from the x-ray tube, appropriate shielding hould be provided. Some of the greatest exposures to patients and medical personnel are from fluoro­ scopic procedures. If the C-arm fluoro unit is used in the ER, special precautions should be in place to ensure that fluoro ex­ posure time is kept to a minimum and that all personnel are wearing protective aprons. A recent study on incidental preg­ nancy in trauma patients noted that fe­ males are very often unaware of their pregnancy status or are unable to respond to questions regarding menses. I The re­ search recommends i mplementation of routine abdominal shielding during radio­ graphic evaluation of females of chi ld­ beari ng age for trauma diagno is. Additionally, the authors recommend re­ quiring a urine screen in addition to serum beta human chorionic gonadotrophin ( I3HCG) for females of childbearing age with traumatic injuries. ( Refer to Chapter 2 for a detailed explanation of the princi­ ples radiation protection.) •

•

•

•

•

' Bochicchio G, Napolitano M . Haan J , Champion H, Scalea T: Incidental pregnancy in trauma patients, J Am Coli Surg 192(5):566, 200 1 .

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PATIENT CARE The fam i l iar "ABCs" of Airway, As with al l i maging procedures, trauma Breathing, and Circulation of basic life procedures require a patient history. The support techniques must be constantly as­ patient may provide this, if he or she is sessed during the radiographic procedures. conscious, or the attending physician may Visual inspection and verbal questioning inform you of the i njury and the patient's enables the radiographer to detennine if status. If the patient is conscious, explain the status of the patient changes during the what you are doing in detail and in terms procedure. Table 1 3- 1 serves as a guide for the patient can under tand. Listen to the the trauma radiographer regarding changes patient 's rate and manner of speech, in status that should be reported immedi­ which may provide insight into his or her ately to the attending physician. The table mental and emotional status. Make eye includes only the comm.on injuries in contact with the patient to provide com­ which the radiographer may be the only fort and reassurance. Keep in mind that a health care professional with the patient trip to the ER is an emotional ly stressful during the i maging procedure. Patient event, regardless of the severity of the in­ with mUltiple trauma injuries or those in respiratory or cardiac arrest usually are jury or illness. Radiographers are often responsible for i maged with a mobile radiographic unit the total care of the trauma patient while while emergency personnel are present in performing diagnostic imaging procedures. the room. I n these situations, the primary Therefore it is critical that radiographers responsibility of the trauma radiographer constantly assess the patient's condition, is to produce quality images in an efficient recognize any signs of decline or distress, manner while practicing ethical radiation and report any change in the status of the protection measures. patient's condition to the attending physi­ cian. The trauma radiographer must be well ver ed in taking vital signs and know­ ing normal ranges, competent in cardiopul­ monary resuscitation (CPR), administra­ tion of oxygen, and dealing with all types of medical emergencies. Tne radiographer must be prepared to perform these proce­ dures when covered by a standing physi­ cian's order or as departmental policy al­ lows. Additionally, the radiographer should be familiar with the location and contents of the adult and pediatric crash carts, and understand how to use the suctioning devices.

TABLE 13-1 Guide for reporting patient status change

Noted symptom

Possible cause

Cool. clammy skin

Shock>

When to report to physician immediately Other symptoms of shock present

Vasovagal reactiont Excessive sweating

(diaphoresis)

Shock>

Other symptoms of shock present

Head injury

Slurred speech

Stroke (cerebrovascular accidenti) Drug or ethanol inftuence§

Accompanied by vomiting. especially if vomiting stops when patient is moved to different position

Agitation or confusion

Head injury Drug or ethanol inftuence§

Accompanied by vomiting. especially if vomiting stops when patient is moved to different position

Vomiting (without abdominal complaints)

(hyperemesis)

Head injury Hyperglycemia'i

Position of patient abruptly stimulates vomiting or abruptly stops vomiting

Drug or ethanol overdose Increased drowsiness

(lethargy)

Shock> Head injury

Other symptoms of shock present or accompanied by vomiting

Hyperglycemia" Shock>

Loss of consciousness (unresponsive to voice

Head injury

or touch)

Hyperglycemiall

Pale or bluish skin pallor

(cyanosis)

Airway compromise

Immediately

Immediately

Hypovolemic shock Bluish nail beds

Circulatory compromise

Immediately

Patient complaints of thirst

Shock>

Other symptoms of shock present

Hyperglycemia'i Hypoglycemia Patient complaints of tingling or numbness

(paresthesia).

Spinal cord injury Peripheral nerve impairment

Accompanied by any symptoms of shock or altered consciousness

or inability to move a limb Seizures Patient states cannot feel your touch

(paralysis)

Extreme eversion of foot

Head injury

Immediately

Spinal cord injury

Accompanied by any symptoms of shock or

Peripheral nerve impairment Fracture of proximal femur or hip joint

altered consciousness Report only if x-ray request speCifies "frog-leg" lateral projection of hip. This movement will exacerbate patient's injury. as well as cause intense pain. Surgical lateral position should be substituted. Watch for changes in abdominal size and firmness.

Increasing abdominal distention and firmness to palpation

Internal bleeding from pelviC

Immediately

fracture or organ laceration

Hypovolemic or hemorrhagic shock is a medical condition where there are abnormally low levels of blood plasma in the body. such that the body is unable to properly maintain blood pressure. cardiac output of blood. and normal amounts of fluid in the tissues. It is the most common type of shock in trauma patients. Symptoms include diaphoresis. cool and clammy skin. decrease in venous pressure. decrease in urine output. thirst. and altered state of consciousness. tVasovagal reaction is also called a vasovagal attack or situational syncope. as well as vasovagal syncope. It is a reflex of the involuntary nervous system or a normal physiologic response to emotional stress. The patient may complain of nausea. feeling flushed (warm). feeling lightheaded. and they may appear pale before they lose consciousness for several seconds. !Cerebrovascular accident (CVA) is commonly called a stroke and may be caused by thrombosis. embolism or hemorrhage in the ves­ sels of the brain. §Drugs or alcohol. Patients under the influence of drugs and/or alcohol are common in the ER. ln this situation. the usual symptoms of shock and head injury are unreliable. Be on guard for aggressive physical behaviors and abusive language. NHyperg/ycemia is also known as diabetic ketoacidosis. The cause is increased blood sugar levels. The patient may exhibit any combina­ tion of symptoms noted. and will have fruity-smelling breath. �Pelvic fractures have a high mortality rate (open fractures are as high as 50%). Hemorrhage and shock are very often associated with this ty p e of injury. Emergency cystograms are often ordered on patients with known pelviC fractures. •

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"Best Practices" in Trauma Radiogra phy Radiography of the trauma patient seldom allows the use of "routine" positions and projections. Additional ly, the traumatized patient requires special attention to patient care techniques while performi ng difficult i maging procedures. The fol lowing best practices provide some universal guide­ l ines for the trauma radiographer. l. Speed- Trauma radiographers must produce quality i mages in the shortest amount of time. Rapidity in performing a diagnostic examina­ tion is critical to saving the patient's l ife. Many practical methods that increase examination efficiency without sacrificing image quality are introduced in this chapter. ll. Accuracy - Trauma radiographers must provide accurate i mages with a minimal amount of distortion and the maximum amount of recorded detail. Alignment of the central ray, the part, and the I R applies in trauma radiography, too. Using the shortest exposure time minimizes the possi­ bility of i maging involuntary and/or uncontrollable patient motion. III. Q Uality-Quality does not have to be sacrificed to produce an image quickly. Do not fall into the trap of using the patient's condition a an ex­ cuse for careless positioning and ac­ cepting less than high quality images.

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precautions must be taken to ensure that perfor­ mance of the imaging procedure does not exacerbate the patient's injuries. The "golden rule" of two projections at right angles from one another still applies. As often as possible, position the tube and the I R, rather than the patient, to obtain the desired projec­ tions.

IV. Positioning-Careful

V. Practice Standard Precautions­

Exposure to blood and body fluids should be expected in trauma radi­ ography. Wear gloves, mask, and gown when appropriate. Place IR and sponges in nonporous plastic to protect from body fluids. Wash hands frequently, especially be­ tween patients. Keep all equipment and accessory devices clean and ready for use. V I. Immobilization-NEVER remove any immobilization device without physician's orders. Provide proper immobi lization and support to in­ crease patient comfort and mini­ mize risk of motion. VD. Anticipation- Anticipating required special projections or diag­ nostic procedures for certain in­ juries makes the radiographer a vital part of the ER team. For example, patients requiring surgery generally require an x-ray of the chest. Fractures of the pelvis often require a cystogram to determine the status of the urinary bladder. Being pre­ pared to perform these examina­ tions quickly and understanding the necessity of these additional images instills confidence in, and creates an appreciation for, the role of the radi­ ographer in the emergency setting.

V III. Attention

to

detail-NEVER

leave a trauma patient (or any pa­ tient) unattended during i maging procedures. The patient's condition may change at any time, and it is the radiographer's responsibility to note these changes and report them immediately to the attending physi­ cian. If you are unable to process i mages while maintaining eye con­ tact with your patient, call for help. Someone must be with the injured patient at all times. I X. Attention to department protocol and scope of practice-Know de­ partment protocols and practice only within your competence and abilities. The scope of practice for radiographers varies from state to state and from country to country. Be sure to study and understand the scope of your role in the emergency setting. Do not provide or offer a patient anything by mouth. A lways ask the attending physician before giving the patient anything to eat or drink no matter how persistent the patient may be. x. Professionalism-Ethical conduct and professionalism in all situations and with every person is a requirement of all health care professionals, but the conditions encountered in the ER can be particularly complicated. Adhere to Code of Ethics for Radiologic Technologists (see Chapter 1 ) and the Radiography Practice Standards. Be aware of the people present or nearby at all times when discussing a patient's care. The ER radiographer is exposed to a myriad of tragic condition . Emotional reactions are common and expected, but must be controlled until the emergency care of the patient is complete.

Radiogra phic Procedu res in Trauma A recent telephone survey of level trauma centers indicated that the common radiography projections ordered for initial trauma surveys are as follows ': Cervical spine, dorsal decubitus posi­ tion (cross-table lateral) Chest, AP (mobile) Abdomen, AP ( KU B and acute abdominal series) Pelvis, AP Cervical spine, AP and obliques Lumbar spine Lower limb Upper limb On reviewing the l ist, the reader should note that skull radiography is not in­ cluded. Most level I trauma centers have replaced conventional trauma skull radi­ ographs ( A P, lateral, Towne, reverse Waters, etc. ) with computed tomography (CT) of the head. The usefulness of con­ ventional radiographs of the skull in trauma has been controversial for over a decade. Research articles have debated the advantages of CT i maging of the cra­ nium over than plain fil m . However, the survey also revealed that some hospitals sti ll perform conventional skull radiogra­ phy. Additionally, many smal ler facilities may not have CT readily available; there­ fore trauma skull positioning remains as valuable knowledge for the radiographer.

This section provides trauma position­ ing instructions for radiography projec­ tions of the following body areas. •

Lateral (dorsal decubitus position) Cervicothoraci c (dorsal decubitus position) AP axial AP axial oblique

•

•

•

Thoracic and lumbar spine

•

Chest

•

Abdomen

Lateral (dorsal decubitus position)

•

AP

•

•

AP AP ( left lateral decubitus position)

•

•

•

'Thomas Wolfe, Methodist Medical Center, Memphis, TN, conducted the survey as a part of his graduate practicum for Midwestern State University.

Cervical spine

•

Pelvis

AP •

Skull

Lateral (dorsal decubitus position) AP or PA AP axial (Towne Method) •

Facial bones

Acanthioparietal Method) •

Limbs

•

Special procedures

( Reverse

Waters

In addition to the dorsal decubitus posi­ tions, AP projections of the thoracic and lumbar spine are usually required for trauma radiographic surveys. The AP pro­ jections of this anatomy vary minimally i n the trauma setting, and therefore are not discussed in detai l. Critical study and clin­ ical practice of these procedures should adequately prepare a radiographer for work in the ER. Certain criteria apply in every trauma i maging procedures, and therefore are ex­ plained here and not included on each procedure in detai l.

PATIENT PREPARATION It is important to remember that the pa­ tient has endured an emotional ly disturb­ ing and distressing event in addition to the physical i njuries he or she may have sus­ tained. If the patient is conscious, speak calmly and look directly in the patient 's eye while explaining the procedures that have been ordered. Do not assume that the patient cannot hear you even if he or she cannot or will not respond. Check the patient thoroughly for items that might cause an artifact on the images. Explain what you are removi ng from the patient and why. Be sure to place all re­ moved personal effects, especially valu­ ables, in the proper container used by the facil ity (i.e., plastic bag), or in the desig­ nated secure area. Every facility has a pro­ cedure regarding proper storage of a pa­ tient's personal belongings. Be sure to know the procedure and fol low it carefully. BREATHING I NSTRUCTIONS Most injured patients have difficulty fol­ lowing the recommended breathing in­ structions for routine projections. For these patients, exposure factors should be set using the shortest possible exposure time to minimize motion on the radi­ ograph; necessitating use of the large fo­ cal spot. The decreased resolution of the large focal spot produces greater resolu­ tion than the significant loss of resolution from patient movement. If a breathing technique is desired, this can be explained to the conscious trauma patient in the usual manner. If the patient is unconscious or unresponsive, then careful attention should be paid to the rate and degree of chest wall movement. If inspiration is de­ sired on the image, then time the exposure to correspond to the highest point of chest expansion. Conversely, if the routine pro­ jection cal ls for exposure on expiration, then the exposure should be made when the patient's chest wall falls to its lowest point.

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IMMOBI LIZATION DEVICES A wide variety of immobilization devices are used to stabilize i njured patients. Standard protocol is to perform radio­ graphic images without removing immo­ bilization devices. Once i njuries have been di agnosed or ruled out, the attending physician gives the order for immobiliza­ tion to be removed, changed, or continued. Many procedures necessitate the use of some sort of immobil ization to prevent in­ voluntary and vol untary motion. Prudent use of such is discussed in many patient care textbooks. The key i ssue in the use of immobi lization in trauma is not to exacer­ bate the patient's injury nor increase his or her discomfort.

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IMAGE RECEPTOR SIZE The IR sizes used in trauma procedures are the same as those specified for the rou­ tine projection of the anatomy of interest. Occasionally, the physician may request that more of a part be incl uded, and then a larger I R is acceptable. CENTRAL RAY, PART, IMAGE RECEPTOR ALIGNM ENT Unless otherwise i ndicated for the proce­ dure, the central ray should be directed perpendicular to the midpoint of the grid and/or IR. Tips for minimizing distortion are detailed on those procedures in which distortion i s a potential threat to i mage quali ty.

IMAGE EVALUATION Ideally, trauma radiographs should be of optimum quality to ensure prompt and ac­ curate diagnosis of the patient's i njuries. Evaluate i mages for proper positioning and technique as i ndicated in the routine projections. Al lowances can be made when true right angle projections (APfPA and lateral) must be altered as a result of patient condition. DOCUME NTATION Deviation from routine projections is a ne­ cessity in many i nstances. It is important to document the alterations in routine projec­ tions for the attending physician and radi­ ologist so that they can properly interpret the images. Additionally, the radiographer often has to determine if the anatomy of in­ terest has been adequately demonstrated, and perform additional projections (within the scope of the ordered examination) on an injured part to aid in proper diagnosis. Notations concerning additional projec­ tions are extremely helpful for the i nter­ preting physicians.

Cervical Spine

.. LATERAL PROJECTlONl Dorsal Decubitus Position

Patient position considerations •

Trauma positioning tips •

•

• •

•

Always perform this projection first, be­ fore any other projections. The attending physician or radiologist must review this image before perform­ i ng other projections. Use a 72 i nch SID whenever attainable. Move the patient 's head and neck as lit­ tle as possible. Shield gonads and other personnel in the room.

•

•

•

• •

Patient general ly is immobil ized on a backboard and in a cervical collar. Have patient relax. his or her shoulders as much as possible. Ensure patient is looking straight ahead without any rotation of the head or neck. Place l R in a holder at top of shoulder (Fig. 1 3-6). Check that the l R i s perfectly vertical. Central ray is horizontal and centered to midpoint of l R .

Structures shown

Entire cervical spine, from sella turcica to the top of T I , must be demonstrated in profi le with minimal rotation and distor­ tion (Fig 13-7). NOTE: If all 7 cervical vertebrae, including the spinous process of C7 and the C7-T I inter­ space, are not clearly visible, a lateral projec­ tion of the cervicothoracic region must be performed.

'See mobile lateral projection in Volume 3. page 257.

Horizontal C R to C4

Fig. 1 3-6 Patient and IR positioned for a trauma lateral projection of the cervical spine us­ ing the dorsal decubitus position.

B

A

Fig. 1 3-7 Dorsal decubitus position lateral projection of the cervical spine performed on a trauma patient. A, Dislocation of the C3 and C4 articular processes (arrow). Note that C7 is not well demonstrated and a lateral projection of the cervicotho­ racic vertebrae should also be performed. B, Fracture of the pedicles with disloca­ tion of C5 and C6. Note superior portion of C7 shown on this image. 11

Cervicothoracic Region

'" LATERAL PROJECTION Dorsal Decubitus Position

•

Trauma positioning tips •

•

•

•

This projection should be performed if the entire cervical spine, including C7 and the interspace between C7 and Tl, is not demonstrated on the dorsal decu­ bitus lateral projection. The patient must be able to move both a rms. Do not move the patient's arms without per­ mission from the attending physician and review of the lateral projection. Coll imate the width of the x-ray beam closely to reduce scatter radiation . If the patient is in stable condition, po­ sition his or her stretcher adjacent to the vertical B ucky to increase efficiency and obtain optimum i mage quality. Shield gonads and other personnel in the room.

Structures shown

Patient position considerations

•

•

•

•

•

•

Supine, usual ly on backboard and in a cervical collar. Have patient depress the shoulder clos­ est to the tube as much as possible. Do not push on patient's shoulder. Instruct the patient to raise arm opposite the tube over his or her head. Assist pa­ tient as needed, but do not use force or move the limb too quickly (Fig. 1 3-8). Ensure patient is looking straight ahead without any rotation of the head or neck. Central ray is horizontal and perpendic­ ular to the IR entering the side of the neck just above the clavicle, passing through the C7-T I interspace. I nstruct patient to breathe normally, if he or she is conscious. If possible, use a long exposure time technique to blur the rib shadows.

The lower cervical and upper thoracic ver­ tebral bodies and spinous processes should be seen in profile between the shoulders. Contrast and density should demonstrate bony cortical margins and trabeculation (Fig. 1 3-9). NOTE: A grid i s required to i mprove image contrast. I f a breathing technique cannot be used, then make the exposure with respiration suspended. Special compensating filters can be used to i mprove image quality.

Horizontal CR to C7-Tl

Fig. 1 3-8 Patient and IR positioned for trauma lateral projection of the cervicothoracic vertebrae using the dorsal decubitus position.

12

Fig. 1 3-9 Dorsal decubitus position lateral projection of the cervicothoracic region performed on a trauma patient. Negative examination. Note excel­ lent image of the C7-Tl joint (arrow).

Cervical Spine

.. AP AXIAL PROJECTION1

Patient position considerations

Trauma positioning tips •

•

•

•

•

•

•

Do not peifo rm this projection until the attending physician has reviewed the lateral projection. This projection is usually performed af­ ter the lateral projection. If patient is on a backboard, either on a stretcher or an x-ray table, gently and slowly lift the backboard and place I R in position under the patient's neck. Move patient's head and neck as little as possible. Col li mate the width of the x-ray beam closely to reduce scatter radiation. Shield gonads and other personnel in the room.

' See slandard projeclion, Volume I, page

•

•

•

•

Supine, usually on backboard and in a cervical collar. Have patient relax his or her shoulders as much as possible. Ensure the patient is 100 lUng straight ahead without any rotation of the head or neck. Place the IR under the backboard, if present, centered to approximately C4 (Fig. 1 3- 1 0) . Central ray is directed 1 5 t o 2 0 degrees cephalad to the center of the IR and en­ tering at C4.

Structures shown

C3 through T I or T2 including interspaces and surrounding soft tissues should be demonstrated with minimal rotation and distortion. Density and contrast should demonstrate cortical margins and soft tis­ sue shadows (Fig. 1 3- 1 1 ). NOTE: I f the patient is not on a backboard or an x-ray table, then preferably, the attending physician should lift the patient's head and neck while the radiographer positions the I R under the patient.

420.

Bucky

Fig. 1 3 - 1 0 Patient and IR positioned for a trauma AP axial projection of cervical vertebrae.

Fig. 1 3- 1 1 AP axial projection of the cervical vertebrae performed on an l l -year-old trauma patient. Note cervi­ cal spine completely dislocated between C-2 and C-3 (arrow). The patient died on the x-ray table after the x-ray examinations were performed.

13

Cervical Spine

.& AP AXIAL OBLIQUE �

PROJECTION

Patient position considerations •

Trauma positioning tips •

•

•

•

•

•

Do not peiform this projection until the attendillg physician has reviewed the lateral projection. If patient is on a backboard, gently and slowly lift the board and place the IR in position. Move patient's head and neck as little as possible. Do not use a grid IR because the com­ pound central ray angle results in grid cut-off. However, many radiography machines do not allow the x-ray tube­ head to move in a compound angle. On these machines only the 45 degree an­ gie is utilized and a grid IR may then be used to improve contrast. Coll i mate the width of the x-ray beam closely to reduce scatter radiation. Shield gonads and olher personnel in the room.

Fig. 1 3- 1 2 Patient and IR positioned for a trauma AP axial oblique projection of the cervical vertebrae. The CR is positioned 45 degrees mediolaterally and if possible. 15 to 20 degrees cephalad. 14

•

•

•

•

•

Supine, usually on backboard and in a cervical collar. H ave patient relax his or her shoulders as much as possible. Ensure patient is looking straight ahead without any rotation of the head or neck. Place the IR under the immobil ization device, if present, centered at the level of C4 and the adjacent mastoid process (about 3 inches lateral to mjdsagittal plane of neck) (Fig. 1 3- 1 2). If a grid IR is used with one central ray angle, the grid lines should be perpendicular to the long axis of the spine. Central ray is directed 45 degrees lat­ eromedially. When a double angle is used, angle 15 to 20 degrees cephalad. The central ray enters sl ightly lateral to midsagittal plane at the level of the thy­ roid cartilage and passing through C4. The central ray exit point should coin­ cide with center of IR.

Structures shown

Cervical and upper thoracic vertebral bod­ ies, pedicles, open intervertebral disc spaces, and open intervertebral foramjna of side opposite of central ray entrance point. This projection provides excellent detail of the facet joints and it is important in detecting subluxations and di slocations (Fig. 1 3- 1 3). If the 1 5 degree cephalic an­ gie is not used the i ntervertebral foramina will be foreshortened. NOTE: If the patient is not on a backboard or an x-ray table, then preferably, the attending physician should l ift the patient's head and neck while the radiographer positions the I R under the patient.

Fig. 1 3- 13 AP axial oblique projection of the cervical vertebrae performed on a trauma patient using a 45 degree angle. Radiograph was made using a non-grid exposure tech­ nique. Negative image. Note excellent alignment of the vertebral bodies and interverte­ bral foramen.

Thoracic and Lumbar Spine

.. LATERAL PROJECTIONS

Structures shown

Dorsal Decubitus Positions Trauma positioning tips •

•

• •

•

Always perform these dorsal decubitus positions before the AP projections of the spine. The attending physician should review the dorsal decubitus lateral projections before performing other projections. Move patient as little as possible. Use of a grid is necessary to i mprove i mage contrast. Utilize the vertical B ucky if possible to maximize posi­ tioning and for optimal image qual ity. Shield gonads and other personnel in the room.

For the thoracic spine, the image should include T3 or T4 to L I . The lumbar spine image shou ld, at a minimum, include T 1 2 to the sacrum. The vertebral bodies should be seen in profi le with mini mal rotation and di stortion. Density and contrast should be sufficient to demonstrate corti­ cal margins and bony trabeculation (Fig. 1 3- 1 5 ).

NOTE: A lateral projection of the cervicotho­ racic spine must be performed to visualize the upper thoracic spine in profi le.

Patient position considerations •

•

•

•

•

•

Patient generally is immobilized and on a backboard. Have patient cross arms over chest to remove them from anatomy of interest. Place the IR I Y2 to 2 inches (3.8 to 5 cm) above the patient's relaxed shoulders for thoracic spine and at the level of il iac crests for lumbar pine (Fig. 13- I 4). If not using the vertical Bucky, ensure that IR is perfectly vertical. Central ray is horizontal, perpendicular to the longitudinal center of the JR, and goi ng through the spine. Col l i mate closely to the spine to reduce scattered radiation and patient dose.

Horizontal CR to top of iliac crest

Fig. 1 3- 14 Patient and IR positioned for trauma lateral projection of the lumbar spine using the dorsal decubitus position and utilizing a vertical Bucky device.

A

B

Fig. 1 3- 1 5 Dorsal decubitus position lateral projection of the lumbar spine performed on a trauma patient. A, Fracture and dislocation of L2 (black arrow). Note backboard (white ar­ row). B, Compression fracture of the body of L2 (arrow). This coned-down image provides better detail of the fracture area. 15

Chest

.. AP PROJECTION 1 .2

Patient position considerations

Trauma positioning tips o

o

o

o

o

o

o

o o

o

Most trauma patients must be radi­ ographed in the supine position. I f it is necessary to see air-fluid levels a cross­ table lateral x-ray beam (dorsal decubi­ tus position) can be performed. Obtain help in l ifting the patient to po­ sition the I R if the stretcher is not equipped with an I R tray. Check for signs of respiratory distress or changes in level of consciousness during radiographic examination and report any changes to the attending physician immediately. A sess abi lity of patient to fol low breathing instructions. Use the maximum SID possible to min­ imize magnification of the heart shadow. Use universal precautions if wounds and/or bleeding are present and protect the IR with plastic covering. Mark entrance and/or exit wounds with radiopaque indicators if evaluating a penetrating injury. Use of a grid improves image contrast. Shield gonads and other personnel in the room.

o

o

o

o

Position the top of I R about l 'li to 2 inches (3.8 to 5 cm) above the patient's shoulders. Move the patient's arms away from tho­ rax and out of col l imated field. Ensure patient is looking straight ahead with chin extended out of the colli­ mated field. Check for rotation by determining if the shoulders are equidistant to I R or stretcher. This position places the mid­ coronal plane parallel to the I R, mini­ mizing i mage distortion. Central ray should be directed perpen­ dicular to the center of the I R at a point 3 inches (7.6 cm) below the jugular notch (Fig. 1 3- 16).

I,

'See standard projection, Volume page 550. 2See mobile projection, Volume 3, page 242.

CR to center of IR

Fig. 1 3- 16 Patient and IR positioned for a trauma AP projection of the chest.

16

Chest

Structures shown

An AP projection of the thorax is demon­ strated. The lung fields should be included in their entirety with minimal rotation and distortion present. Adequate aeration of the lungs must be imaged to demonstrate the lung parenchyma ( Fig. 1 3- 1 7) . NOTE: Ribs are somewhat visible o n a n AP projection, necessitating the use of a grid l R to increase image contrast. Use proper breathing instructions and techniques to ensure adequate visualization of ribs of interest.

A B

Fig. 1 3- 1 7 AP upright projection of the chest performed on a trauma patient. A, Multiple buckshot in chest caused a hemopneumothorax. Arrows show the margin of the col­ lapsed lung with free air laterally. Arrowhead shows fluid level at the costophrenic angle, left lung. B, Open safety pin lodged in esophagus of a 1 3-month-old baby.

17

Abdomen

.. AP PROJECTION 1 .2 Trauma positioning tips •

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•

•

•

•

•

•

Use of a radiographic table and a B ucky provides optimum image quality. Before moving the patient, verify transfer to table with the attending physician. If transfer is not possible, use of a grid IR is required. Determine the possibil ity of fluid accu­ mulation within the abdominal cavity to determine appropriate exposure factors. For patients with blunt force or projec­ tile injuries, check for signs of internal bleeding during radiographic examina­ tion and report any changes to the at­ tending physician immediately. Mark entrance and/or exit wounds with radiopaque markers if evaluating pro­ jectile injuries. Assess the abi l ity of the patient to fol­ low breathing instructions. Use standard precautions if wounds or bleeding are present and protect IR with plastic covering. Shield gonads, if possible, and other personnel in the room.

Patient position considerations •

•

•

•

•

Ask ER personnel to assist in transfer­ ring patient to radiographic table, if possible. I f transfer is not advisable, obtain assis­ tance to carefully lift the patient to po­ sition the grid IR under the patient. Center the grid I R at the level of the il­ iac crests and ensure that the pubic symphysis is included (Fig. 1 3- 1 8). On patients with a long torso a second AP projection of the upper abdomen may be required to demonstrate the di­ aphragm and lower ribs. If the patient is on a stretcher, check that the grid IR is parallel with the pa­ tient's midcoronal plane. Correct tilting with sponges, sandbags, rolled towels, etc. The grid I R must be perfectly hori­ zontal to prevent grid cut-off and i mage distortion. If unable to correct tilt on grid IR, then angle CR to maintain part­ J R-CR alignment. Central ray is directed to the center of the JR.

'See standard projection Volume 2, page 80. 'See mobile projection Volume 3, page 246.

Bucky Fig. 1 3- 1 8 Patient and IR positioned for a trauma AP projection of the abdomen.

18

Abdomen

Structures shown

An AP projection of the abdomen is demonstrated. The entire abdomen, in­ cluding pubic symphysis and diaphragm should be i ncluded without distortion or rotation. Density and contrast should be adequate to demonstrate tissue interfaces, such as lower margin of liver, kidney shadows, psoas muscles and cortical mar­ gins of bones (Fig. 1 3- 1 9).

B

A

Fig. 1 3- 1 9 AP projection of abdomen performed on a trauma patient. A, Table knife in the stomach along with other small metallic foreign bodies swallowed by the patient. B, Coin in the stomach swallowed by patient.

19

Abdomen

.. AP PROJECTION 1 .2 left lateral Decubitus Position

Patient position considerations o

Trauma positioning tips o

o

o

o

o

o

o

Use of the vertical B ucky provides op­ timum i mage quality. If patient must be i maged using a mobile radiographic unit, a grid IR is required. Verify with the attending physician that the patient movement is possible and if the image is needed to assess fluid accu­ mulation or free air in abdorrunal cavity. The left lateral decubitus position demonstrates free air i n abdorrunal cav­ ity because the density of the liver pro­ vide good contrast for visualization of any free air. If fluid accumulation is of primary in­ terest, the side down, or dependent side, must be elevated off of the stretcher or table to be completely demonstrated. Check for signs of internal bleeding during radiographic exarrunation and report any changes to the attending physician immediately. Use universal precautions if wounds or bleerung are present and protect the I R with plastic covering. Mark a l l entrance and exit wounds with radiopaque mark­ ers when imaging for penetrating injuries Shield gonads, if possible, and person­ nel in the room.

o

o

o

o

o

Carefully and slowly turn the patient into the recumbent left lateral position. Flex the knees to provide stability. If the i mage is being taken for visual­ ization of fluid, carefully place a block under the length of the abdomen to en­ sure that the entire right side is visual­ ized. Ensure that the midcoronal plane is ver­ tical to prevent i mage distortion. Center the IR 2 i nches (5 cm) above the il iac crests to i nclude the diaphragm (Fig. 1 3-20). The patient should be in the lateral po­ sition at least 5 rrunutes before the ex­ posure to allow any free air to rise and be visual ized. Central ray is directed horizontal and perpendicular to the center of the IR.

NOTE: A lateral projection using the dorsal de­ cubitus position may be substituted for this projection i f patient is too ill or injured to be properly positioned in a left lateral position. (Position will be identical to the dorsal decubi­ tus position, lateral projection of the l umbar spine. See Fig. 1 3- 1 4 . )

Structures shown

Air and fluid levels within the abdominal cavity are demonstrated. This projection is especially helpful in assessing free air in the abdomen when an upright position cannot be used. Density and contrast should be adequate to demonstrate tissue i nterfaces, such as lower margin of liver, kidney shadows, psoas muscles, and corti­ cal margins of bones (Fig. 1 3-2 1 ).

I See standard projection Volume 2, page 82. 2See mobile projection Volume 3, page 248.

Horizontal CR to center of IR Fig. 1 3-20 Patient and I R positioned for a trauma A P projection of abdomen using the left lateral decubitus position and utilizing a vertical Bucky device.

20

Fig. 1 3-21 Left lateral decubitus position AP projection of the abdomen performed on a trauma patient. Free intraperi­ toneal air is seen on the upper or right side of the abdomen (arrow). The radiograph is slightly underexposed to demon­ strate the free air more easily.

Pelvis

'" AP PROJECTlON l ·2

Patient position considerations

Trauma positioning tips •

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•

Up to 50% of pelvic fractures are fatal as a result of vascular damage and shock. The mortality risk increases with the energy of the force and the health of the victim. Pelvic fractures have a high incidence of internal hemorrhage. A lert the at­ tending physician immediately if ab­ domen becomes distended and firm. Hemorrhagic shock is common with pelvic and abdominal injuries. Reassess patient's level of consciousness repeat­ edly while performing radiographic examinations. Do not attempt to internally rotate l imbs for true AP projection of proxi­ mal femurs on thjs projection . Col l i mate closely to reduce scatter radi ­ ation. Shield gonads, if possible, and other personnel in the room.

•

•

•

•

•

The patient is supine, possibly on back­ board or in trauma pants. Carefu lly and slowly transfer the pa­ tient to radiographic table to allow use of Sucky. If unable to transfer, use a grid IR posi ­ tioned under the immobilization device or patient. Ensure that grid is horizontal and parallel to the patient's midcoronal plane to minimize distortion and rota­ tion. Carefully al igned to the central ray to mini mize di tortion and rotation. Position the I R so the center is 2 i nches (5 cm) inferior to the ASIS or 2 inches (5 cm) superior to the pubic symphysis. Central ray is directed perpendicular to the center of the IR (Fig. 1 3-22). Check colli mated field to ensure that the il iac crests and hip joints are in­ cl uded.

Structures shown

The pelvis and proximal femora should be demonstrated i n their entirety with mini­ mal rotation and distortion. Femoral necks will be foreshortened and lesser trochanters will be seen. Optimum density and contrast should demonstrate bony tra­ beculation and soft tissue shadows (Fig. \ 3-23). NOTE: Diagnosis of pelvic fractures in the ER is often immediately fol lowed by an emer­ gency cystogram procedure. The necessary an­ cillary equipment and contrast media should be readily avai lable.

'See standard projection Volume I , page 355. 2See mobile projection Volume 3, page 250.

Bucky Fig. 1 3-22 Patient and IR positioned for a trauma AP projection of the pelvis.

A

B

Fig. 1 3-23 AP projection of the pelviS performed on a trauma patient. A, Entire right limb torn off after be­

ing hit by a car. The pelvic bone was disarticulated at the pubic symphysis and S-I joint. The patient sur­ vived. B, Separation of the pubic bones (arrowheads) anteriorly and associated fracture of the left ilium (arrow).

21

Cranium

.. LATERAL PROJECTIONl

Patient position considerations

Dorsal Decubitus Position

o

Trauma positioning tips o

o

o

o

o

o

Since the scalp and face are very vascu­ l ar, these areas tend to bleed profusely. Protect IRs with plastic covering and practice universal precautions. A grid IR is used for this projection. Elevate the patient' s head on radiolu­ cent sponge only after cervical injury such asfracture or dislocation has been ruled out. Vomiting is a ymptom of intracranial i njury. If patient begins to vomit, log roll to lateral position to prevent aspi­ ration and alert the attending physician immediately. Alert attending physician immediately if there is any change in the patient 's level of consciousness or if pupils are unequal. Col li mate closely to reduce scatter radi ­ ation. Shield gonads and other personnel in the room.

o

o

o o

Have the patient relax his or her shoul­ ders. After cervical spine injury has been ruled out, the patient's head may be po­ sitioned to align i nterpupillary l i ne per­ pendicular to the I R and the midsagittal plane vertical . If patient i s wearing a cervical collar, carefully minimize rotation and tilt of cranium. Ensure that the IR is vertical . Central ray is directed horizontal enter­ i ng perpendicular to a point 2 i nches (5 cm) above the EAM (Fig. 1 3-24).

'See standard projection Volume 2, page 306.

Horizontal CR 2 inches above EAM Fig. 1 3-24 Patient and IR positioned for a trauma lateral projection of the cranium using the dorsal decubitus position. Note sponge in place to raise head to demonstrate poste­ rior cranium (after checking lateral cervical spine radiograph).

22

Cranium

Structures shown

A profi le image of the superimposed halves of the cranium is seen with detail of the side closest to the lR demonstrated (Fig. 1 3-25 ). With some i njuries, airlfluid levels can be demonstrated in the sphe­ noid sinuses. NOTE: The supine lateral position may be used on a patient without a cervical spine injury. See Volume 2. page 306.

B

A

Fig. 1 3-25 Dorsal decubitus position lateral projection of the cranium performed on a trauma patient. A, Two gunshot wounds entering at the level of C l and traveling forward to the face and lodging in the area of the zygomas. Note bullet fragments in the EAM area. B, Multiple frontal skull fractures (arrows) caused by hitting the windshield during an auto accident.

23

Cranium

..

AP PROJECTlON l AP AXIAL PROJECTION­ TOWNE METHOD 2

Patient position considerations •

Trauma positioning tips •

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•

•

•

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•

Profuse bleeding should be anticipated with head and facial i njuries. Use uni­ versal precautions and protect IRs and sponges with plastic. Cervical spine injury should be ruled out before attempting to position the head. AP projection is used for injury to the anterior cranium. AP axial projection, Towne method demonstrates the poste­ rior cranium. Vomiting i s a symptom of an intracra­ nial injury. If patient begins to vomit, log roll patient to lateral position to prevent aspiration and alert attending physician immediately. A Lert attending physician if patient's LeveL of consciousness decreases or if pupiLs are unequal. Collimate closely to reduce scatter radi­ ation. A grid IR or B ucky should be used to ensure proper i mage contrast. ShieLd gonads and other personneL in the room.

•

•

•

If available and the patient's condition allows, carefully and slowly transfer the patient to the x-ray table using the im­ mobilization device and proper transfer technique . Transfer allows the use of the B ucky and minimizes risk of injury to the patient when positioning the IR. I f the patient is not transferred to the ra­ diographic table, the grid IR should be placed under the immobi lization de­ vice. If no such device is present, the attending physician should carefully lift the patient's head and neck while the radiographer positions the grid I R under the patient. After a cervical spine injury has been ruled out, the patient's head may be po­ sitioned to place the OML or IOML and midsagittal plane perpendicular to the I R . If the patient is wearing a cervical col­ lar, the OML or IOML cannot be posi­ tioned perpendicular. For the AP axial projection, Towne method, the central ray angle may have to be increased up to 60 degree caudad-maintaining a 30 degree angle to the OML.

ISee standard projection Volume 2, page 3 1 2. 'See standard projection Volume 2, page 3 1 4.

Bucky Fig. 1 3-26 Patient and IR positioned for a trauma AP projection of the cranium.

24

Fig. 1 3-27 AP projection of the cranium performed on a trauma patient. Fracture of the occipital bone (arrow).

Cranium

•

•

For a n AP projection, the central ray enters perpendicular to the nasion (Fig. 1 3-26). An AP axial projection with the central ray di rected 1 5 degrees cepha­ lad is sometimes performed in place of, or to accompany the AP projection . For the AP axial projection, Towne method, position the top of the IR at the level of the cranial vertex . The central ray is then directed 30 degrees caudad to the OML or 37 degrees to [OML (Fig. 1 3-27). The central ray passes through the EAMs and exits the fora­ men magnum.

Structures shown

The AP projection demonstrates the ante­ rior cranium (Fig. 1 3-28), The AP axial projection, Towne method, demonstrates the posterior cranium and foramen mag­ num (Fig. 1 3-29).

Bucky Fig. 1 3-28 Patient and IR positioned for a trauma AP axial projection Towne method, of the cranium using a 30 degree CR an­ gulation.

Fig, 1 3-29 AP axial projection, Towne method, performed on a trauma patient. Gunshot wound to the head. Metal clip (upper arrow) indicates entrance of the bullet on the an­ terior cranium. Flattened bullet and fragments (lower arrow) lodged in the area of C2.

25

Facial Bones

.. ACANTHIOPARI ETAL PROJECTlON l

Patient position considerations •

REVERSE WATERS M ETHOD Trauma positioning tips •

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Anticipate profuse bleeding with facial trauma. Protect I Rs with plastic cover­ ing and practice universal precautions. Cervical spine i njury should be ruled out before attempting to position the head. A Lert attending physician if patient 's LeveL of consciousness decreases or if pupiLs are unequal. A grid IR or B ucky is used to ensure proper image contrast. Coll i mate closely to reduce scatter radi­ ation. ShieLd gonads and other personnel in the room.

' See standard projection Volume 2, page 364.

•

•

•

•

•

If available and the patient's condition allows, carefully and slowly transfer the patient to the x-ray table using the im­ mobilization device and proper transfer techniques. Transfer allows the use of the Bucky and minimizes risk of injury to the patient when positioning the IR. I f the patient is not transferred to the ra­ diographic table, the grid I R should be placed under the immobilization de­ v ice. If no such device is present, the attending physician should carefully lift the patient's head and neck while the radiographer position the grid IR under the patient. If possible, the IOML should be posi­ tioned approxi mately perpendicular to the I R . Note angle of MML. The midsagittal plane should be per­ pendicular to prevent rotation. Central ray is angled cephalad until parallel to MML. The central ray enters the acanthion (Fig. 1 3-30). Center the IR to the central ray.

Structures shown

The superior facial bones are demon­ strated (Fig. 1 3-3 1 ). The image hould be similar to the parietoacanthial projection or routine Waters method and demonstrate symmetry of the face.

C.R.

I

Bucky Fig. 1 3-30 Patient and IR positioned for a trauma acanthioparietal projection, Reverse Water's method of the cranium.

A

B

Fig. 1 3-31 Acanthioparietal projections, reverse Water's method, performed on trauma patients for demonstration of the facial bones. A, Fracture of the right orbital floor (arrow) with blood-filled maxillary sinus (note, no air in the sinus). Patient hit face on steering wheel during auto accident. B, Blowout fracture of the left orbital floor (arrow) with

blood-filled maxillary sinus (note, no air

26

in the sinus). Patient was hit with a

fist.

Upper limb

Trauma positioning tips

o

o

Use standard precautions and cover I Rs and positioning aids in plastic if wounds are present. When lifting an injured limb, support at both joints and lift slowly. Lift only enough to place the IR under the part­ sometimes ollly I to 2 inches (2.5 to 5 cm). Always obtain help in lifting in­ jured limbs and positioning the I Rs to mini mize patient di comfort. If the limb is severely injured, do not at­ tempt to position for true AP or lateral projections. Expose the two projec­ tions, 90 degrees apart, moving the in­ jured limb as little as possible.

CR to center of IR Fig. 1 3-32 Patient and IR positioned for a trauma AP projection of forearm.

o

o

o

o

Check the patient's status during radio­ graphic examination. Be aware that shock can occur from crushing injuries to extremities. Long bone radiographs must incl ude both joints on the image. Separate examinations of the adjacent joints may be required if injury indi­ cates. Do not attempt to "short cut" by only performing one projection of the long bone. Shield gonads and other personnel in the room.

2 inch block

Patient position considerations

o

I f possible, demonstrate desired posi­ tion for the conscious patient. Assist the patient in attempting to assume the po­ sition, rather than moving the injured limb. If the patient is unable to position the limb close to that required, move the I R and x-ray tube t o obtain desired projec­ tion (Figs. 1 3-32 to 1 3-35).

Horizontal CR to center of IR

Fig. 1 3-33 Patient and IR positioned for a trauma "cross table" lateral projection of forearm.

27

Upper limb

•

•

•

•

Shoulder injuries should be initially i m­ aged "as is" without rotating the l imb. The "reverse" PA oblique projection of the scapular Y (an AP oblique) is useful in demonstrating dislocation of the glenohumeral joint with minimal pa­ tient movement. The patient is turned up 45 degrees and supported in position (Figs. 1 3-36 and 1 3-37. ) I f i maging while the patient is sti l l on a stretcher, check to make sure the I R is perfectly horizontal to minimize image distortion. Central ray must be directed perpendic­ ular to the IR to minimize distortion. I mmobilization techniques for the I R and upper l i mb are very useful i n ob­ taining optimal i mage with minimal pa­ tient discomfort.

Fig. 1 3-34 A P projection o f the forearm performed o n a trauma patient. Fracture of the mid-portion of the radius and ulna (arrows).

C.R.

1 4S" wedge

Bucky Fig. 1 3-35 'Cross-table- Iateral projection of the forearm performed on a trauma patient. Gunshot wound to the forearm with fracture of the radius and ulna and extensive soft tis­ sue damage.

28

Fig. 1 3-36 Patient and IR positioned for a trauma AP oblique projection of the shoulder to demonstrate the scapular Y. (Reverse of the PA oblique. scapular Y. see Chapter 5.)

Upper Limb

Structures shown

I mages of the anatomy of interest, 90 de­ grees from one another, should be demon­ strated. Density and contrast should be sufficient to visualize cortical margins, bony trabeculation, and surrounding soft tissues. Both joints should be included in projections of long bones. Projections of adjacent joints must be centered to the joint to properly demonstrate the articular ends ( Figs. 1 3-38 and 1 3-39).

CR to center of IR Fig. 1 3-38 Patient and IR positioned for a trauma AP projection of humerus.

Fig. 1 3-37 AP oblique projection of the shoulder (reverse of the PA oblique, scapular Y) performed on a trauma patient. Several fractures of the scapula (arrows) with significant displacement.

Fig. 1 3-39 AP projection of the humerus performed on a trauma patient. Fracture of the mid-shaft of the humerus.

29

Lower Limb

Trauma positioning tips •

•

•

•

•

Use standard precautions and cover I Rs and positioning aids in plastic if open wounds are present. I mmobi lization devices are often present with injuries to the lower limbs, espe­ cially in cases with suspected femur fractures. Peiform image procedures with immobilization in pLace, unLess di­ rected to remove by attending physician. When lifting an injured l imb, support at both joints and Lift sLowLy. Lift onLy enough to place the IR under the part­ sometimes onLy J to 2 inches (2.5 to 5 em). Always obtain help in lifting in­ jured l imbs and positioning I Rs to min­ imize patient discomfort (Fig. 1 3-40). If the l i mb is severely injured, do not at­ tempt to position for true AP and lateral projections. Take two projections, 90 degrees apart, movi ng the injured limb as l ittle as possible. Long bone examinations must include both joints. Separate images may be required.

•

•

•

•

Exami nations of the adj acent joints may be required if the condition indi­ cates. Central ray and IR must be prop­ erly centered to the joint of interest to properly demonstrate the anatomy. Check on patient status during radio­ graphic examination. Be aware that shock can occur with severe injuries to the lower extremities. A grid IR should be u ed on thicker anatomical parts such as the femur. ShieLd gonads and other personnel in the room.

Patient position considerations

•

•

•

•

Demonstrate or describe desired posi­ tion for patient and al low patient to at­ tempt to assume the position, rather than moving the injured limb. Assist patient as needed. If patient is unable to position limb close to the required true position, move IR and x-ray tube to obtain pro­ jection (Figs. 1 3-4 1 and 1 3- 42). If i maging while the patient is stil l on a stretcher, check to make sure the I R is perfectly horizontal to minimize i mage distortion. Central ray must be directed perpendic­ ular to IR to minimize distortion. I mmobilization techniques for the I R and lower l i m b are extremely useful to obtain optimum quality with minimal patient di comfort.

Fig. 1 3-40 Proper method of lifting the lower limb for placement of the IR (for AP projec­ tion) or placement of elevation blocks (for 'cross-table" lateral). Lift only high enough to place the IR or blocks underneath. Note two hands used to gently lift this patient with a broken leg.

30

Lower Limb

7

2 inch block

Horizontal CR to center of IR

Fig. 1 3-41 Patient and IR positioned for a trauma "cross-table" lateral projection of lower leg. IR and central ray may be moved superiorly or inferiorly to center for other portions of the lower limb. Note positioning blocks placed under the limb to elevate so all of the anatomy of interest is seen .

A

B

Fig. 1 3-42 "Cross-table" lateral projection of the lower limb performed on a trauma pa­ tient. A, Dislocation of the tibia from the talus (double arrows) and fracture of the fibula (orrow). B, Complete fracture and displacement of the femur. The Proximal femur is seen in the AP projection and distal femur is rotated 90 degrees at the fracture point resulting in a lateral projection. Note artifacts caused by immobilization devices.

31

Lower Limb

Structures shown

I mages of the anatomy of interest, 90 de­ grees from each other should be demon­ strated. Density and contrast should be suf­ ficient to visualize cortical margins, bony trabeculation, and surrounding soft tissues. Both joints should be included in examina­ tions of long bones. I mages of articulations mu t be properly centered to demonstrate anatomy properly (Figs. 1 3-43 and 1 3-44).

Wedge

Fig. 1 3-43 Patient and IR positioned for a trauma AP projection of foot or toes. Note IR is supported with sandbags for positioning against the foot.

A

B

Fig. 1 3-44 AP projection of the foot performed on a trauma patient. A, Fracture and disloca­ tion of the tarsal bones with exposure technique adjusted for optimal image of this area. B, Gunshot wound to the great toe.

32

SPECIAL PROC ED URES I N TRAU MA

...7:�

·-.

Many i njuries, once diagnosed, may re­ quire additional follow-up evaluation via a special procedure or additional i maging modality. CT is used extensively to further investigate fractures and head injuries. CT is also very useful in revealing the extent of injuries sustained from blunt traumas. In penetrati ng trauma, CT is invaluable in helping trace the ballistic path and deter­ mining organs affected by the projectile (Fig. 1 3-45 ) . Angiography may be used to evaluate vascular damage. The role of ul­ trasound in emergency diagnosis is also increasing. These special ized i magi ng modalities may require a scout radiograph before the patient is referred to a different modality.

A

B

Fig. 1 3-45 A, AP and lateral CT "scout" images of the cranium. Note knife placement in the cranium. Conventional cranium radiographs were not obtained on this trauma pa­ tient. Patient was sent directly to the CT scanner for these images and sectional images before going to surgery. Patient recovered and returned home. 8, Axial and coronal CT sectional images of the cranium at the level of the eye. Patient was shot in the left eye with a BB gun. Note BB (arrow). Adjacent black area is air. Patient now has monocular vision. (A, Images courtesy of Tony Hofmann. RT(R) (eT] Shands Hospital School of Radiologic Technology. Jacksonville. FL; B, Images courtesy of Mark H. Layne. RT(R) .)

33

Cystography

Intravenous Urogra phy

Within the trauma radiographer's role falls the responsibility of performing ER spe­ cial procedures requiring the administra­ tion of contrast media. For example, once an initial abdominal or pelvis radiograph has demonstrated a fracture of the pelvis, cystography is often ordered by the emer­ gency physician to determine injury to the bladder (Fig. 1 3-46). The trauma radiogra­ pher must be prepared to alter the routine procedure to fit the condition of the pa­ tient. Optimal images are obtained if the patient is stable enough to be moved to the radiographic table. Assistance is needed to properly transfer the patient to the table. I f the examination must b e performed using a mobile radiographic unit, obtain assis­ tance to properly lift the patient to center the I R . Ensure that all personnel and nearby patients are properly shielded.

Additionall y, intravenous urography ( IVU) may be ordered to assess blunt or penetrating trauma that may affect the kidneys. General ly, the procedure is ab­ breviated, with only one or two images taken after the contrast is administered to determine if the contrast media is being properly excreted (Fig. 1 3-47 ) . The trauma radiographer must again be pre­ pared to alter the procedure to accommo­ date the patient's condition. Critical to the performance of special procedures on trauma patients is pre­ paredness. The availabil ity of all neces­ sary ancillary equipment and contrast me­ dia should be inventoried at the beginning of each shift. Time is of the essence, and having all necessary materials available is critical to producing the images in the most efficient manner.

Fig. 1 3-46 AP pelvis for trauma cystogram of the urinary bladder. Pelvic trauma from auto accident. Note separation of the pubic symphysis (arrows). Patient survived after surgery. Vertical line near right side of image and ovoid area (arrowhead) are from the backboard.

34

Fig. 1 3-47 AP abdomen performed during a trauma IVU on a gunshot victim. Bullet entered the point marked by a surgical clip in upper left quadrant and stopped in the left hip (see bullet fragments on left femoral neck). Note medial displacement of the contrast filled left ureter (arrows) caused by retroperitoneal hemorrhage.

Selected bibliography

Berquist TH, editor: Imaging of orthopedic trallma and surgel)" ed 2. New York, 1 992, Raven Press. Bishop and Associates: Trauma care. Retrieved May 29, 200 1 from http://www.traumacare. comlTerms.html, 1 998. Cwinn A : Pelvis and hip. I n Rosen P, editor: Emergency medicine: concepts and clinical practice. ed 4, St Louis, 1 998. Mosby. Drafke M: Trauma and mobile radiography, Phi ladelphia, 1 990, FA Davis.

Keats TE, editor: Emergency radiology. Chicago, 1 984. Mosby. Mancini ME. Klein J: Decision making in trauma management: a mulfidisciplinCIIY approach. Philadelphia, 1 99 1 , Decker. McCon JJ. Mindelzun, editors: Trauma radiol­ ogy. New York. 1 990. Churchill-Livingstone.

Office of Statistics and Programming, National Centers for I njury Prevention and Control, CDC. Data source: National Center for Health Statistics Vital Statistics System ( 1 998). 1 0 leading causes of death, United States, all races, both sexes. Retrieved August 8 , 200 I from http://www.cdc.gov/ncipc/

wisQMs/default.htm. On-line Medical Dictionary. (n.d.) Retrieved June 27, 200 I from http://www.graylab.ac.ukl

cgi-bin/omd Rosen P, editor: Diagnostic radiology in emer­ gency medicine, St Louis, 1 992, Mosby. Texas Department of Health. Essential General Trauma Facility Criteria Defined. Retrieved August, 200 I from http://www.tdh.state.tx.us! hCQs/ems/filel ib.htm.

icholson DA, Driscoll PA, Forbes W. St. C, edi tors: A B C of emergency radiology, London, 1 995, BMJ Publishing Group.

35

OUTUNE ANATOMY, 39

SUM MARY OF PROJ ECTIONS

PROJECTIONS,

Page

Essential

POSITIONS,

Anatomy

& METHODS Projection

44

Parotid gland

Tangential

46

Parotid and submandibular glands

Lateral

48

Submandibular and sublingual gland

Axial

Position

Method

R or L INTRAORAL

Mouth The mouth, or oral cavity, is the first divi­ sion of the digestive system (Fig. 1 4- 1 ). It encloses the dental arches and receives the saliva secreted by the sal ivary glands. The cavity of the mouth is divided into ( I ) the oral vestibule, the space between the teeth and the cheeks, and (2) the oral cavity, or mouth proper, the space within the dental arches. The roof of the oral cavity is fomled by the hard and soft palates. The floor is formed principally by the tongue, and it communicates with the pharynx pos­ teriorly via the orophQ/yn.x. The hard palate is the most anterior por­ tion of the roof of the oral cavity. I t is formed by the horizontal plates of the max­ i l lae and palatine bones. The anterior and lateral boundaries are formed by the inner wall of the maxillary alveolar processes, which extend superiorly and medial ly to blend with the horizontal processes. The height of the hard palate varies consider­ ably, and it determines the angulation of the inner surface of the alveolar process. The angle is less when the palate is high and is greater when the palate is low.

The soft palate begins behind the last molar and is suspended from the posterior border of the hard palate. H ighly sensitive to touch, the soft palate is a movable mus­ culomembranous structure that functions chiefly as a partial septum between the mouth and the pharynx. At the center of the i nferior border the soft palate is pro­ longed i nto a small, pendulous process called the uvula. On each side of the uvula, two arched folds extend laterally and i nferiorly. The anterior arches project forward to the sides of the base of the tongue. The posterior arches project pos­ teriorly to blend with the posterolateral walls of the pharynx. The triangular space between the anterior and the posterior arches is occupied by the palatine tonsil.

The tongue is si tuated in the floor of the oral cavity, with its base di rected posteri­ orly and its apex directed anteriorly (see Figs. 1 4- 1 and 1 4-2 ). The tongue is freely movable. It is composed of numerous muscles and is covered with a mucous membrane that varies in complexity in the different regions of the organ. The extrin­ sic muscles of the tongue form the greater part of the oral floor. The mucous mem­ brane covering the undersurface of the tongue is reflected laterally over the re­ mainder of the floor to the gums. This part of the floor l ies under the free anterior and lateral portions of the tongue and is called the sublingual space. Posterior movement of the free anterior part of the tongue is re­ stricted by a median vertical band, or fold, of mucous membrane called the frenulum of the tongue, which extends between the undersurface of the tongue and the sublin­ gual space. On each side of the frenu lum, extending around the outer limits of the sublingual space and over the underlying sal ivary glands, the mucous membrane is elevated into a crestlike ridge called the sublingual fold. In the relaxed state the two folds are quite promi nent and are in contact with the gums. The teeth serve the function of mastica­ tion, the process of chewing and gri ndi ng food into smal l pieces. During mastica­ tion the teeth cut, grind, and tear the food, which is then mixed with sal iva, swal­ lowed, and later digested. The saliva soft­ ens the food, keeps the mouth moist, and contributes digestive enzymes .

.;'"--=:::::��-\-- Hard palate Posterior arch Anterior arch Tonsil

Uvula

Tongue

�-�-+- Soft palate

---il!;f"TiU��_ Sublingual space

--��-.?2���

Orifice of submandibular duct Fig. 1 4- 1 Anterior view of oral cavity.

Frenulum of tongue Sublingual fold

Fig. 1 4-2 Anterior view of undersurface of tongue and floor of mouth.

39

Salivary Glands The three pairs of salivary glands produce approximately 1 l iter of saliva each day. The glands are named the parotid, the submandibular, and the sublingual (Fig. 1 4-3). Each gland is composed of numer­ ous lobes, with each lobe containing small lobules. The whole gland is held together by connective tissue and a fine network of blood vessels and ducts. The minute ducts of the lobules merge into l arger tribu­ taries, which unite and form the l arge ef­ ferent duct that conveys the saliva from the gland to the mouth.

The parotid glands, the largest of the salivary glands, each consist of a flattened superficial portion and a wedge-shaped deep portion (Fig. 1 4-4). The superfic ial part lies immediately anterior to the exter­ nal ear and extends inferiorly to the mandibular ramus and posteriorly to the mastoid process. The deep, or retro­ mandibular, portion extends medially to­ ward the pharynx. The parotid duct runs an­ teriorly and medially to open into the oral vestibule opposite the second upper molar.

The submandibular glands are fairly large, i rregularly shaped glands. On each side a submandibular gland extends poste­ riorly from a point below the first molar almost to the angle of the mandible (Fig. 1 4-5). Although the upper part of the gland rests against the inner surface of the mandibular body, its greater portion pro­ jects below the mandible. The sub­ mandibular duct extends anteriorly and superiorly to open into the mouth on a small papilla at the side of the frenulum of the tongue.

Parotid gland Sublingual ducts Submandibular --jrl·'·�'�-"'.;..I.� duct Sublingual gland

Fig. 1 4-3 Salivary glands from the left lateral aspect.

Anterior

Tongue

Ramus of mandible Parotid gland

Dens

Spinal cord

Fig. 1 4-4 Horizontal section of face, showing relation of parotid gland to mandibular ramus. Auricle is not shown.

40

The sublingual glands, the smal lest pair, are narrow and elongated in form (see Fig. 1 4-5). These glands are located in the floor of the mouth beneath the sub­ l ingual fold. Each is in contact with the mandible lateral ly and extends posteriorly from the side of the frenulum of the tongue to the submandibular gland. Numerous small sublingual ducts exist. Some of these ducts open into the floor of the mouth along the crest of the subl in­ gual fold, and others open into the sub­ mandibular duct. The main subli ngual duct opens beside the orifice of the sub­ mandibular duct.

Anterior

Mandible

Oropharynx --t:f-f.l'B-L':;;;'�

Cervical vertebral body

Sublingual gland Submandibular gland Tip of parotid gland

Fig. 1 4-5 Horizontal section of face, showing relation of submandibular and sublingual glands to surrounding structures. Auricle is not shown.

SUMMARY OF ANATOMY* Mouth

Salivary glands

oral vestibule oral cavity oropharynx hard palate soft palate uvula anterior arches posterior arches tonsil tongue apex sublingual space frenulum of the tongue sublingual fold teeth

parotid glands parotid ducts submandibular glands submandibular ducts sublingual glands sublingual ducts

·See Addendum at the end of the volume for a summary of the changes in the anatomic terms that were introduced in the 9th edition. 41

."��.�'

RADI OGRAPHY

Sialography

SUM MARY OF PATHOLOGY Condition

Definition

Calculus

Abnormal concretion of mineral salts, often called a stone

Epiglottitis

Inflammation of the epiglottis

Fistula

Abnormal connection between two internal organs or between an organ and the body surface

Foreign Body

Foreign material in the airway

Salivary Duct Obstruction

Condition preventing the passage of saliva through the duct

Stenosis

Narrowing or contraction of a passage

Tumor

New tissue growth where cell proliferation is uncontrolled

Sialography is the term applied to radio­ logic examination of the salivary glands and ducts with the use of a contrast mate­ rial, usually one of the water-soluble iodi­ nated media. Because of improvements in computed tomography (CT) and magnetic resonance i maging ( M R I ) techniques, sialography i performed Ie s often than it once was. When the presence of a salivary stone or lesion is suspected, CT or MRI is often the modality of choice. However, sialography remains a viable tool when a definitive diagnosis is needed for a prob­ lem related to one of the salivary ducts. The procedure is used to demonstrate such conditions as inflammatory lesions and tumors, to determine the extent of salivary fistulae, and to localize diverticu­ lae, strictures, and calcul i . Because the glands are paired and the pairs are in such close proximity, only one gland at a time can be exami ned by the sialographic method (Fig. 1 4-6).

Submandibular duct

Submandibular gland

Fig. 1 4-6 Sialogram showing opacified submandibular gland.

42

Sialography i nvolves the fol lowing steps: I nject the radiopaque medium into the main duct. From there the contrast flows into the i ntraglandular ductules, making it possible to demonstrate the surrounding glandular parenchyma, as well as the duct system (Fig. 1 4-7). Obtain prelimjnary radiographs to detect any condition demonstrable without the use of a contrast medium and to estab­ lish the optimum exposure technjque. About 2 or 3 minutes before the sialo­ graphic procedure, give the patient a se­ cretory sti mulant to open the duct for ready identi fication of its orifice and for easier passage of a cannula or catheter. For this purpose, have the patient suck a wedge of fresh lemon. On completion of the examination, have the patient suck on another lemon wedge to stimu­ late rapid evacuation of the contrast medium. Take a radiograph about 10 minutes af­ ter the procedure to verify clearance of the contrast medium, if needed.

•

•

•

Most physicians inject the contrast medium by manual pressure (i.e., with a syringe attached to the cannula or catheter). Other physicians advocate delivery of the medium by hydrostatic pressure only. The latter method requires the use of a water­ soluble iodinated medium, with the con­ trast solution container (usually a syringe barrel with the plunger removed) attached to a drip stand and set at a distance of 28 inches (70 cm) above the level of the pa­ tient's mouth. Some physicians perform the filli ng procedure under fluoroscopic guidance and obtain spot radiographs. (Articles cited in the bibliography provide detai led descri ptions of the numerous methods of performjng sialography.)

•

Parotid duct

Parotid gland

Fig. 1 4-7 Sialogram showing parotid gland in patient with­ out teeth.

43

Parotid Gland

TANGENTIAL PROJECTION

•

Image receptor: 8 x 1 0 inch ( 1 8 x

24 cm) lengthwise

Position of part

Position of patient

•

Place the patient in either a recumbent or seated position. Because the parotid gl and l ies mjdway between the anterior and posterior sur­ faces of the skull , obtain the tangential projection of the glandular region from either the posterior or the ante­ rior direction.

Fig. 1 4-8 Tangential parotid gland. supine position.

Supine body position •

• •

With the patient supine, rotate the head sl ightly toward the side being examined so that the parotid area is perpendicular to the plane of the I R . Center the I R t o the parotid area. With the patient's head resting on the oc­ ciput, adjust the head so that the man­ djbular ramus is parallel with the longitu­ dinal axis of the IR (Fig. 1 4-8).

Fig. 1 4-9 Tangential parotid gland. prone position.

Orbit

Zygomatic arch

Mandibular ramus Parotid gland area

Fig. 1 4· 1 0 Tangential parotid gland. An examination of right cheek area to rule out tumor reveals soft tissue fullness and no calcification. 44

Fig. 1 4- 1 1 Right cheek (arrow) distended with air in mouth, same patient as in Fig. 1 4- 1 0. No abnormal finding in region of parotid gland.

Parotid Gland

Prone body position •

• •

•

• •

With the patient prone, rotate the head so that the parotid area bei ng examined is perpendicular to the plane of the IR. Center the I R to the parotid region. With the patient's head resting on the chin, adj ust the flexion of the head so that the mandibular ramus is parallel with the longitudinal axis of the IR (Fig. 1 4-9). When the parotid (Stensen's) duct does not have to be demonstrated, rest the patient's head on the forehead and nose. Shield gonads. Respiration: I mproved radiographic quality can be obtained, particularly for the demonstration of calculi , by having the patient fil l the mouth with air and then puff the cheeks out as much as possible. When this cannot be done, ask the patient to suspend respiration for the exposure.

Central ray •

Perpendicular to the plane of the I R , di­ rected along the lateral surface of the mandibular ramus

Structures shown

A tangential projection demonstrates the region of the parotid gland and duct. These structures are clearly outlined when an opaque medium is used (Figs. 1 4- 1 0 to 1 4- 1 4). EVALUATION CRITERIA The following should be clearly demon­ strated: • Soft tissue density • Most of the parotid gland lateral to, and clear of, the mandibular ramus • Mastoid overlapping only the upper portion of the parotid gland

Fig. 1 4- 1 2 Tangential parotid gland, with right cheek distended with air. Considerable calcification is seen in region of parotid gland (arrows) .

Mastoid process

Opacified parotid gland

Mandibular ramus

Fig. 1 4- 1 3 Tangential parotid gland showing opacification.

Fig. 1 4- 1 4 Tangential parotid gland show­ ing opacification.

45

Parotid and Submandibular Glands

LATERAL PROJECTION

Position of part

R or l position •

Image receptor: 8 x 1 0 inch ( l 8 X

24 cm) lengthwise Position ot patient

Submandibular gland

Parotid gland

•

Place the patient in a semi prone or seated and upright position. •

•

With the affected side closest to the IR, extend the patient's neck so that the space between the cervical area of the spine and the mandibular rami is cleared. Center the IR to a point approximately I inch (2.5 cm) superior to the man­ dibular angle. Adjust the head so that the midsagittal plane is rotated approximately 1 5 de­ grees toward the IR from a true lateral position.

•

•

•

Center the I R to the inferior margin of the angle of the mandible. Adjust the patient's head in a true lat­ eral position (Fig. 1 4- 1 5 ). Iglauer' suggested depressing the floor of the mouth to displ ace the sub­ mandibular gland below the mandible. When the patient's throat is not too sen­ sitive, accomplish this by having the patient place an index finger on the back of the tongue on the affected side. Shield gonads. Respiration: Suspend.

Central ray •

Perpendicular to the center of the I R and directed ( I ) a t a point I inch (2.5 cm) superior to the mandibular angle to demonstrate the parotid gland or (2) at the i nferior margin of the mandibular angle to demonstrate the submandibu­ lar gland

' Iglauer S : A simple maneuver to increase the visi­ bility of a salivary calculus in the roentgenogram, Radiology 2 1 :297, 1 933.

Fig. 1 4- 1 5 Lateral submandibular gland.

46

Parotid and Submandibular Glands

Structures shown

A lateral image demonstrates the bony structures and any calcific deposi t or swel ling i n the unobscured areas of the parotid (Figs. 1 4- 1 6 and 1 4- 1 7) and sub­ mandi bu lar glands ( Fig. 1 4- 1 8). The glands and their ducts are well outli ned when an opaque medi um is used. EVALUATION CRITERIA The following should be clearly demon­ strated: • Mandibular rami free of overlap from the cervical vertebrae to best show the parotid gland superi mposed over the ramus • Superi mposed mandibular rami and an­ gles if no tube angulation or head rota­ tion is used for the submandibular gland • Oblique position for the parotid gland

Fig. 1 4- 1 6 Lateral parotid gland showing opacified gland and parotid duct (arrow).

NOTE: An oblique projection is often necessary to obtai n an i mage of the deeper portions of the parotid and submandibular glands. Any of the axiolateral projections of the mandible can be used for this purpose (see Chapter 2 1 ).

Fig. 1 4- 1 7 Lateral parotid gland showing opacification and blockage of parotid duct (arrows).

Fig. 1 4- 1 8 Lateral submandibular gland showing opacifi­ cation and submandibular duct (arrow).

47

Submandibular and Sublingual Glands

AXIAL PROJECTION INTRAORAL METHOD

Placement of film •

Image receptor: Occlusal fi l m-57 X

76 mm (2� X 3 inch) Position of patient •

•

•

Elevate the patient's thorax on several firm pil lows. Flex the patient's knees to relax the ab­ dominal muscles and thereby allow full extension of the neck. Adj ust the shoulders to lie in the same transverse plane.

•

•

•

•

• •

Tape a side marker (R or L) on one cor­ ner of the exposure surface of the oc­ clusal film packet. Place the fil m in the mouth with the long axis directed transversely. Center the packet to the mjdsagittal plane, and gently insert it far enough so that it is in contact with the anterior borders of the mandibular rami. I nstruct the patient to gently close the mouth (to hold the packet in position). After placement of the occlusal film, fully extend the patient's neck and rest it on the vertex with the midsagittal plane vertical (Figs. 1 4- 1 9 and 1 4-20). Shield gonads. Respiration: S uspend.

Central ray •

Perpendicular to the plane of the film and directed to the intersection of the midsagittal plane and a coronal plane passing through the second molars

Structures shown

An axial image of the floor of the mouth is demonstrated, showing the entire sub­ l i ngual gland areas and the duct and an­ teromedial part of the submandibular gland areas (Fig. 1 4-2 1 ). EVALUATION CRITERIA The fol lowing should be clearly demon­ strated: • Soft tissue density of the floor of the mouth • Both sides of the mandible and dental arches symmetric • Subl ingual glands in their entirety along with a p0l1ion of the submandibular glands when the film includes the lower molars NOTE: This i the only projection that gives an unobstructed i mage of the sublingual gland re­ gions. It is sometimes necessary to use the ver­ ticosubmental projection for the submandibu­ lar gland regions to demonstrate tumor masses or lesions that l ie posterior or lateral to the floor of the oral cavity (Fig. 1 4-22).

Fig. 1 4- 1 9 Axial submandibular and sublin­ gual glands.

Fig. 1 4-20 Intraoral method. 48

Fig. 1 4-21 Axial submandibular and sublin­ gual glands. Calcification (arrow) is seen in the sublingual region.

Fig. 1 4-22 Verticosubmental submandibular gland (arrow) and duct (arrowhead).

15 Pharynx

•

Larynx

•

Thyroid Gland

OURINE

SUM MARY OF PROJ ECTIONS

PROJECTIONS,

Page

Essential

POSITIONS,

Anatomy

& METHODS Projection

64

Pharynx and larynx

AP

66

Soft palate, pharynx, larynx

Lateral

Position

R or L

Method

. l.1I

ANATOMY

Neck The neck occupies the region between the skull and the thorax ( Figs. 1 5- 1 and 1 5-2). For radiographic purposes the neck is di­ vided into posterior and anterior portions in accordance with the tissue composition and function of the structures. The proce­ dures that are required to demonstrate the

osseous structures occupying the posterior division of the neck are described in the discussion on the cervical vertebrae in Chapter 8. The portions of the central ner­ vous system and of the circulatory system that pass through the neck are described in Chapters 25 and 26.

The portion of the neck that l ies in front of the vertebrae is composed largely of soft tissues. The upper parts of the respi­ ratory and digestive systems are the prin­ cipal structures. The thyroid and parathy­ roid glands, as well as the larger part of the submandibular glands, are also located in the anterior portion of the neck.

Thyroid Gland The thyroid gland consists of two lateral . lobes connected at their lower thirds by a narrow median portion called the isthmus (Fig. 1 5-3 ) . The lobes are approximately 2 i nches (5 cm) long, I � i nches (3 cm) wide, and % inch ( 1 .9 cm) thick. The isth­ mus lies at the front of the upper part of the trachea, and the lobes lie at the sides. The lobes reach from the lower third of the thyroid cartilage to the level of the first thoracic vertebra. Although the thyroid gland is normal ly suprasternal in position, it occasionally extends into the superior aperture of the thorax.

Nasopharynx ----+-1-++-"'-'

----r\--ti,--- Soft palate

Uvula -------fl.f-t-HIM: Epiglottis ------ff-+-+'IIHVocal folds ----H----M+

Piriform recess

i;:f""'-IPirt--cIt-- Rima glottidis Larynx -----�,\--lIt� Laryngo- ------\'0:-­

pharynx

Parathyroid Glands The parathyroid glands are small ovoid bodies, two on each side, superior and in­ ferior. These glands are situated one above the other on the posterior aspect of the adjacent lobe of the thyroid gland.

Fig. 1 5- 1 Interior posterior view of neck.

Pharyngeal tonsil Nasopharynx ---+1�+III. Uvula -H-:::c:+ : .... ;:: ...'fI Oropharynx ---jc..;� -

Epiglottis

Superior ----I parathyroid Thyroid gland

-+f--+....,IIIU.

-

Thyroid cartilage

---­

\.'-;\,��='--:::;,.-L-- Hyoid bone

'T-�AIf--- Isthmus of thyroid

Larynx --r-d-.Ittt-�-n. Laryngeal pharynx

--I""-H-+-- Trachea I-H�-- Thyroid cartilage '-+-J�--t:'-+t-H-+--- Esophagus Fig. 1 5-2 Sagittal section of face and neck.

Inferior parathyroid gland

L-___ Trachea

Esophagus

Fig. 1 5-3 Lateral aspect of laryngeal area demonstrating the thyroid gland and the isthmus that connects its two lobes.

51

Pharynx The pharynx serves as a passage for both air and food, and thus is common to the respiratory and digestive systems (see Fig. 1 5-2). The pharynx is a musculomembra­ nous, tubular structure situated in front of the vertebrae and behind the nose, mouth, and larynx. Approximately 5 inches ( 1 3 cm) i n length, the pharynx extends from the undersurface of the body of the sphe­ noid bone and the basilar part of the oc­ cipital bone inferiorly to the level of the disk between the sixth and seventh cervi­ cal vertebrae, where it becomes continu­ ous with the esophagus. The pharyngeal cavity is subdivided i nto nasal, oral, and laryngeal portions.

Hyoid bone

Thyroid cartilage

It��--- Trachea Fig. 1 5-4 Anterior aspect of larynx.

Base of tongue

The nasopharynx l ies posteriorly above Larynx the soft and hard palates. (The upper part The Larynx is the organ of voice (Figs. 1 5- 1 of the hard palate forms the floor of the through 1 5-5). Serving as the air passage nasopharynx.) Anteriorly the nasopharynx between the pharynx and the trachea, the communicates with the posterior aper­ larynx is also one of the divisions of the res­ tures of the nose. Hanging from the poste­ piratory system. rior aspect of the soft palate is a small The larynx is a movable, tubular struc­ conical process, the uvula. On the roof ture, is broader above than below, and is and posterior wal l of the nasopharynx, be­ approxi mately 1 J;; inches (3.8 cm) in tween the ori fices of the auditory tubes, length. Situated below the root of the the mucosa contains a mass of lymphoid tongue and in front of the laryngeal phar­ tissue known as the pharyngeal tonsil (or ynx, the larynx is suspended from the hyoid adenoids when enlarged). Hypertrophy of bone and extends from the level of the su­ this tissue interferes with nasal breathing perior margin of the fourth cervical vertebra and is common in children. This condition to its junction with the trachea at the level of is well demonstrated in a lateral radi­ the inferior margin of the sixth cervical ver­ ograph of the nasopharynx. tebra. The thin, leaf-shaped epigLottis is sit­ The oropharynx is the portion extending uated behind the root of the tongue and the from the soft palate to the level of the hyoid hyoid bone and above the laryngeal en­ bone. The base, or root, of the tongue trance. It has been stated that the epiglottis forms the anterior wall of the oropharynx. serves as a trap to prevent leakage into the The Laryngeal pharynx l ies posterior to the larynx between acts of swallowing. The larynx, its anterior wall being formed by thyroid cartilage forms the laryngeal the posterior surface of the larynx. The la­ prominence, or Adam 's appLe. The inlet of the larynx is oblique, slant­ ryngeal pharynx extends inferiorly and is continuous with the esophagus. ing posteriorly as it descends. A pouchlike The air-containing nasal and oral pha­ fossa called the piriform recess is located rynges are well visualized in lateral im­ on each side of the larynx and external to ages, except during the act of phonation, its orifice. The piriform recesses are well when the soft palate contracts and tends to shown as triangular areas on frontal pro­ obscure the nasal pharynx. An opaque jections when insufflated with air medium is required for demonstration of (Valsalva's maneuver) or when fi l led with the lumen of the laryngeal pharynx, al­ an opaque medium. though it can be distended with air during the VaLsaLva 's maneuver (an increase in in­ trathoracic pressure produced by forcible expiration effort against the closed glottis).

----:;;::::iJl..-_

Epiglottis _----r--::

Vocal fold (true vocal cord)

Vestibular fold (false vocal cord)

Rima glottidis open

Rima glottidis closed

Fig. 1 5-5 Superior aspect of larynx (open and c losed true vocal folds).

52

The entrance of the larynx is guarded superiorly and anteriorly by the epiglottis and laterally and posteriorly by folds of mucous membrane. These folds, which extend around the margin of the laryngeal inlet from their junction with the epiglot­ tis, function as a sphincter during swal­ lowing. The laryngeal cavity is subdi­ vided into three compartments by two pairs of mucosal folds that extend antero­ posteriorly from its lateral walls. The su­ perior pair of folds are the vestibular folds, or false vocal cords. The space above them is cal led the laryngeal vestibule. The lower two folds are sepa­ rated from each other by a median fissure called the rima glottidis. They are known as the vocal folds, or true vocal folds (see Fig. 1 5-5 ) . The vocal cords are vocal liga­ ments that are covered by the vocal folds. The l igaments and the rima glottidis make up the vocal apparatus of the larynx and are collectively referred to as the glottis.

SUMMARY OF ANATOMY* Thyroid gland

Pharynx

larynx

isthmus

nasopharynx soft palate hard palate uvula pharyngeal tonsil oropharynx hyoid bone laryngeal pharynx

epiglottis thyroid cartilage piriform recess laryngeal cavity vestibular folds (false vocal cords) laryngeal vestibule rima glottidis vocal folds (true vocal cords) glottiS

Parathyroid glands

superior inferior

'See Addendum at the end of the volume for a summary of the changes in the anatomic terms that were introduced in the 9th edition.

53

..'�

RAD I OGRAPHY

Soft Palate, Pharynx, and Larynx: Methods of Examination The throat structures may be examined with or without an opaque contrast medium. The technique employed depends on the abnor­ mality being i nvestigated. Computed to­ mography (CT) studies are often performed to radiographically demonstrate areas of the palate, pharynx, and larynx with little or no discomfort to the patient. Magnetic reso­ nance imaging (MRl) is also used to evalu­ ate the larynx. The radiologic modality se­ lected is often determined by the institution and physician. The radiologic examinations discussed in the following sections are per­ formed less often than in the past.

Obtain a second lateral image after 0.5 ml of the creamy barium suspension is injected into each nasal cavity to coat the superior surface of the soft palate and the posterior wall of the nasopharynx. Morgan et al l described a technique for evaluating abnormalities of chewing and swallowing in children. I n this technique the chewing and swallowing function is injected with ci neradiography as the child chews barium-i mpregnated chocolate fudge. (The fudge recipe was i ncluded i n their article.) Cleft palate studies are performed in the fol lowing manner: Seat the patient laterally upright with the image receptor centered to the na­ sopharynx. Make the exposures during phonation to demonstrate the range of movement of the soft palate and the position of the tongue during each of the fol lowing sounds2.3: d-a-h, m-m-m, s-s-s, and e-e-e.

o

o

o

PALATOGRAPHY B l och and Quantril l l used a posltlve­ contrast technique to investigate suspected tumors of the soft palate. The technique in­ volves the fol lowing steps: Seat the patient laterally before a verti­ cal grid device with the nasopharynx centered to the I R . For the first palatogram, have the pa­ tient swallow a small amount of a thick, creamy barium sulfate suspension to coat the inferior surface of the soft palate and the uvula. o

o

' M organ JA et al: Barium-i mpregnated chocolate fudge for the study of chewing mechanism in chil­ dren, Radiology 94:432, 1 970. 'Randall P, O' Hara AE, Bakes FP: A simple roentgen examination for the study of soft palate function in patients with poor speech, Plas/ Recolls/r S/lrg 2 1 :345. 1 958. 'O' Hara AE: Roentgen evaluation of patients with cleft palate, Radial Ciill North Am I: I , 1 963.

' Bloch S, Quantrill J R : The radiology of nasopha­ ryngeal tu mors, i n cluding positive contrast na­ sopharyngography, S Air Med J 42: 1 030, 1 968.

NASOPHARYNGOGRAPHY Hypertrophy of the pharyngeal tonsil or adenoids i clearly delineated in a direct lateral projection centered to the na­ sopharynx, % i nch ( 1 .9 cm) directly ante­ rior to the external acoustic meatus, as shown in Fig. 1 5-6. The i mage must be exposed duri ng the intake of a deep breath through the nose to ensure filling of the nasopharynx with air. Mouth breathing moves the soft palate posteriorly to near approximation w ith the po terior wall of the nasopharynx and thus causes i nspired air to bypass the nasopharynx as it is di­ rected inferiorly into the larynx. Positive-contrast nasopha ryngog raphy is performed to assess the extent of na­ sopharyngeal tumors (Fig. 1 5-7). Some ex­ aminers recommend an iodized oil for this examination. 1 Others prefer finely ground barium sulfate, either in paste form2 or ap­ plied dry with a pressure blower. Pre l i m inary radiographs commonly consist of a submentovertical (SMV) pro­ jection of the skull and an upright lateral projection centered to the nasopharynx, % inch ( 1 .9 cm) directly anterior to the ex­ ternal acoustic (auditory) meatus. When 'Johnson TH, Green AE, Rice EN: asopharyngo­ graphy: its technique and uses, Radiology 88: 1 1 66, 1 967. 'Khoo FY, Chia KB, Nalpon J: A new technique of contrast examination of the nasopharynx with cine­ Auorography and roentgenography, AJR 99:238. 1 967.

Roof of contrast- =coated palate

�

_ _ _ _ _ _

Fig. 15·6 Lateral pharyngeal tonsil demonstrating hyper· (arrows).

trophy

54

Fig. 1 5·7

Lateral nasopharyngogram.

an iodized oil or a bari um paste is used, the steps are as fol lows: Place the patient on the exam ining table in the supine position after local anes­ thetization. Elevate the shoulders to extend the neck enough to permit the orbitomeatal line to be adjusted at an angle of 40 to 45 degrees to a horizontal plane. Keep the head in this position through­ out the examination.

•

•

•

•

•

•

Both before and after instillation of contrast medium into the nasal cavities, obtain basal projections with the central ray directed midway between the mandibular angles at an angle of 1 5 to 20 degrees cephalad. Obtain lateral projections with a hori­ zontal central ray centered to the na­ sopharynx. On completion of this phase of the ex­ amination, have the patient sit up and

blow the nose. This act evacuates most of the contrast medium, and the re­ mainder will be swallowed. Reports in­ dicate that none of the contrast medium is aspirated because the swallowing mechanism is triggered before the ma­ terial reaches the larynx. Additional studies in the upright posi­ tion are then made as directed by the ex­ amining physician ( Figs. 1 5-8 to 1 5- 1 1 ).

Fig. 1 5-8 SMV nasopharyngography. right ninth nerve sign. Note the asymmetry of the nasopharynx, with ftattening on the right and presence of irregularity (arrows).

Fig. 1 5-9 Lateral nasopharyngography, right ninth nerve sign, lat­ eral projection shows a mass in the posterior aspect of the na­ sopharynx (arrow) with an umbilication in the same patient as in Fig, 1 5-8.

Fig. 1 5- 1 0 SMV nasopharyngography of a 69-year-old woman with a long history of decreased hearing on left side and left fa­ cial paresthesia (burning, prickling). Nasopharynx is asymmetric with blunting of cartilage at opening of auditory tube (arrows).

Fig. 1 5- 1 1 Lateral nasopharyngography showing a shallow niche at C1 level of axis. Niche may represent an ulcer (arrow). 55

Chittinand, Patheja, and Wisenberg ' de­ scribed an opaque-contrast nasopharyngo­ graphic procedure in which the patient is not required to keep the neck in an un­ comfortable extended position for the en­ tire examination. The fol lowing steps are observed: Seat the patient before a vertical grid device. Obtajn prelimjnary lateral and submen­ tovertical projections. Do not use topical anesthetization. (According to the origi nators, the pro­ cedure does not require anesthesia. ) Using a standard spray bottle, i ntroduce water i nto each nasal cavity. Then spray Micropaque powder into each nostril with a powder blower connected to a pressure unit. Take two SMV projections--one at rest and one during a modified Valsalva's maneuver-and one lateral projection. Have the patient blow the nose. Medium not expelled is swallowed. Immediate chest radiographs should not reveal bar­ ium in the lungs, and 24-hour follow-up radiographs should reveal complete clearing of the nasopharynx. •

•

The shortest exposure time possible must be used for studies made during deglutition. The following steps should be observed: Ask the patient to hold the barium sul­ fate bolus in the mouth until signaled and then to swallow the bolus in one movement. If a mucosal study is to be attempted, ask the patient to refrain from swallow­ ing agai n. Take the mucosal study during the mod­ ified Valsalva's maneuver for double­ contrast delineation.

3 . Simultaneously with the posterior thrust

of the tongue, the larynx moves anteri­ orly and superiorly under the root of the tongue, the sphincteric folds nearly closing the laryngeal inlet (orifice). 4. The epiglottis divides the passing bolus and drains the two portions lateral ly into the piriform recesses as it lowers over the laryngeal entrance. The bolus is projected into the pharynx at the height of the anterior movement of the larynx (Figs. 1 5- 1 2 to 1 5- 1 4). It is necessary to synchronize a rapid exposure with the peak of the act.

•

•

•

•

•

•

PHARYNGOGRAPHY Opaque studies of the pharynx are made with an ingestible contrast medium, usu­ ally a thick, creamy mixture of water and barium sulfate. This examination is fre­ quently carried out using fluoroscopy with spot-film i mages only. These or conven­ tional projections are made during deglu­ tition ( wallowing).

Fig. 1 5- 1 2 Lateral projection with exposure made at peak of laryngeal elevation. Hyoid bone (white arrow) is almost at level of mandible. Pharynx (between large ar­ rows) is completely distended with barium.

A

Fig. 1 5- 13 AP projection of the same pa­ tient as in Fig. 1 5- 1 2. Epiglottis divides bolus into two streams, filling the piriform recess below. Barium can also be seen entering upper esophagus.

B

c

Deglutition

The act of swallowing is performed by the rapid and hjghly coordinated action of many muscles. The following points are i mportant in radiography of the pharynx and upper esophagus: 1 . The mid area of the tongue becomes depressed to collect the mass, or bolus, of material to be swallowed. 2. The base of the tongue forms a central groove to accommodate the bolus and then moves superiorly and inferiorly along the roof of the mouth to propel the bolus into the pharynx. 'Chittinand S, Patheja S S , Wisenberg MJ : Barium nasopharyngography, Radiology 98:387, 1 96 1 .

56

Fig. 1 5- 1 4 AP projection of pharynx and upper esophagus with barium. A, Head was turned to right. with resultant asymmetric filling of pharynx. Bolus is passing through left pir­ iform recess, leaving right side unfilled (arrow). B, Lateral projection after patient swal­ lowed barium, showing a diverticulum (arrow). C, Lateral projection made Slightly later, showing only filling of upper esophagus.

Some fluoroscopic equipment can ex­ pose up to 1 2 frames per second using the I OO-mm or I 05-mm cut or roll film. Many institutions with such equipment use it to spot radiograph patients in rapid sequence during the act of swal lowing. Another technique is to record the fl uoroscopic im­ age on videotape or c i ne fi lm. The recorded i mage may then be studied to identify abnormal ities during the active progress of deglutition.

Gunson method

Gunson l offered a practical suggestion for synchronizing the exposure with the height of the swallowing act in deglutition studies of the pharynx and superior esoph­ agus. Gunson's method consists of tying a dark-colored shoestring (metal tips re­ moved) snugly around the patient's throat above the thyroid cartilage (Fig. 1 5- 1 5). Anterior and superior movements of the larynx are then shown by the elevation of the shoestring as the thyroid cartilage moves anteriorly and immediately there­ after by the displacement of the shoestring as the cartilage passes superiorly. It is desirable to have the exposure co­ incide with the peak of the anterior move­ ment of the larynx, the instant at which the bolus of contrast material is projected into the pharynx. However, as stated by Templeton and Kredel ,2 the action is so rapid that satisfactory fi lling is usuall y ob­ tained if the exposure is made as soon as anterior movement is noted.

LARYNGOPHARYNGOGRAPHY Stationary or tomographic negative-con­ trast studies of the air-contai ning lary n­ gopharyngeal structures are made in both AP and lateral projections. AP pro­ jections are made with the patient in ei­ ther the supine or seated and upright po­ sition, with the head extended enough to prevent superi mposition of the mandibu­ lar shadow on that of the l arynx. Lateral projections are made with a soft ti ssue radiograph technique and the patient in the upright position. Negative-contrast studies of the laryn­ gopharyngeal structures provide consider­ able information about alterations in the normal anatomy and function of laryn­ gopharyngeal structures. Both negative­ and positive-contrast AP projections are made during the respiratory and stress ma­ neuvers discussed in the following sections.

'Gunson EF: Radiography of the pharynx and upper esophagus: shoestring method, Xray Techll 33: I , 1 96 1 . 'Templeton FE, Kredel RA: The cricopharyngeal sphincter. Laryngoscope 53: I, 1 943.

A

B

c

Fig. 1 5- 1 5 A, Ordinary dark shoelace has been tied snugly around patient's neck above the Adam 's apple. B, Exposure was made at peak of superior and anterior movement of larynx during swallowing. At this moment the pharynx is completely filled with barium, which is the ideal instant for making x-ray exposure. C, Double-exposure photograph em­ phasizing movement of Adam's apple during swallowing. Note extent of anterior and su­ perior excursion (arrows). 57

Quiet inspiration

Quiet inspiration tests abduction of the vo­ cal cords. The resultant radiograph should show the cords open (abducted), with an uninterrupted column of air extending from the laryngeal vestibule inferiorly into the trachea (Figs. 1 5- 1 6 and 1 5- 1 7).

Piriform recess Vestibule of larynx

Normal (expiratory) phonation

Fig. 1 5- 1 6 AP projection during inspiration.

Normal (expiratory) phonation tests adduc­ tion of the vocal cords. The patient is asked to take a deep breath and, while exhaling slowly, to phonate either a high-pitched e-e-e or a low-pitched a-a-h. The resultant image should show the closed (adducted) vocal cords just above the break in the air column at the closed rima glottidis (Figs. 1 5- 1 8 and 1 5- 1 9). Phonation is normally performed during expiration. This test is now generally referred to as normal or ex­ piratory phonation to distinguish it from the inspiratory phonation.

Fig. 1 5- 1 7 AP projection linear tomogram during inspiration.

Laryngeal vestibule Rima glottldis (vocal fold)

Fig. 1 5- 1 8 AP projection during phonation of e-e-e.

Rima glottidis (vocal fold)

Fig. 1 5- 1 9 AP projection linear tomogram during phonation of e-e-e.

58

Inspiratory phonation

Modified Valsalva's maneuver

Powers, Holtz, and Ogural introduced the use of inspiratory phonation for demon­ stration of the laryngeal ventricle. This maneuver i s also called reverse phonation and aspirate or aspirant maneuver. The patient is asked to exhale com­ pletely then to inhale slowly while making a harsh, stridulous sound with the phona­ tion of e or another high-pitched sound. This test adducts the vocal cords, moves them inferiorly, and balloons the ventricle for clear deli neation ( Fig. 1 5-20).

The modified Valsalva's maneuver tests the elasticity of the laryngeal pharynx (hypopharynx) and the piriform recesses. The resultant radiograph should show the glottis closed and the laryngeal pharynx and piriform recesses distended with air (Fig. 1 5-22). For the modified Valsalva's maneuver, the patient pinches the nostri ls together with the thumb and forefinger of one hand . Keeping the mouth closed, the pa­ tient makes and sustains a sl ight effort to blow the nose. Alternatively, the patient can blow the cheeks outward against the closed nostrils and mouth as if blowing i nto a horn or balloon. The selected respiratory and stress ma­ neuver employed must be carefully ex­ plained and demonstrated just before its use. The patient should perform the ma­ neuver one or more ti mes until able to per­ form it correctly.

Valsalva's maneuver

Valsalva's maneuver shows complete clo­ sure of the glottis. Thi s maneuver tests the elasticity and functional integrity of the glotti s (Fig. 1 5-2 1 ). For the true Valsalva's maneuver, the patient is asked to take a deep breath and to hold the breath in while bearing down as if trying to move the bowels. This act forces the breath against the closed glottis, which i ncreases both i ntrathoracic and in­ traabdomi nal pressure.

TOMOLARYNGOGRAPHY Tomographic studies of the laryngopha­ ryngeal structures, either before or after the i ntroduction of a radiopaque contrast medium, are made in the frontal plane. One set is usual ly made during quiet in­ spiration (see Fig. 1 5- 1 7 ) and one during normal (expi ratory) phonation (see Fig. 1 5- 1 9), but the stress maneuvers are used as i ndicated . The rapid-travel l i near sweep is general ly considered to be the technique of choice for these stud ies, and the exposures are made during the first half of a wide arc (40 to 50 degrees) to prevent overlap streaking by the facial bones and teeth.

' Powers WE. Holtz S, Ogura J: Contrast examination of the larynx and pharynx: inspiratory phonation. AJR 92:40, 1 964.

Fig. 1 5-20 AP projection, inspiratory phona­ tion, showing laryngeal ventricle (horizontal black arrows), true vocal folds (white ar­ rows), and piriform recesses (black arrow­ heads).

Fig. 1 5-21 AP projection demonstrat­ ing true Valsalva's maneuver and showing closed glottiS (arrow).

Fig. 1 5-22 AP projection, demonstrating modified Valsalva's maneuver showing air­ filled piriform recesses (arrows).

59

POSITIVE-CONTRAST LARYNGOPHARYNGOGRAPHY Positive-contrast examinations of the lar­ ynx and laryngopharynx are usually per­ formed to determine the exact site, size, and extent of tumor masses. The examination is conducted using fluoroscopy with spot radi­ ographs and/or cineradiographic record­ ings. In conjunction with the examination procedure described by Powers, McGee, and Seaman, I is the medium most com­ monly used, although other radiopaque me­ dia are employed. A mild sedative may be administered before the examination. The following steps are then observed: After satisfactory prelimi nary radi ­ ographs are obtained, seat the patient upright, and then anesthetize the laryn­ gopharyngeal structures with a topical anesthetic to inhibit the gag, cough, and deglutition reflexes if needed. •

' Powers WE, McGee HH, Seaman WB: Contrast ex­ amination of the larynx and pharynx, Radiology 68: 1 69, 1 957.

60

•

•

•

•

Give the patient explicit instructions on each of the test maneuvers to be used. Caution the patient to avoid coughing and swallowing after the introduction of the radiopaque medium (Figs. 1 5-23 to 1 5-25). For the adm inistration of the medium, attach a syringe loaded with the speci­ fied amount of iodized oil to a curved metal cannula. With the patient seated upright, slowly drip the iodized oil over the back of the tongue or directly into the larynx, coat­ ing all structures of the larynx and laryngopharynx. Examine the patient fluoroscopically, making spot radiographs at the height of each of the various test maneuvers. Some exami ners obtai n ci neradio­ graphic recordings with a continuous catheter dri p of thin barium or iodized oil into the larynx.

Valleculae epiglattica Epiglottis Vallecula epiglottica

Larynx Piriform recess Vestibule of larynx

Piriform recess Laryngeal ventricle

Trachea

Trachea

Fig. 1 5-23 Normal AP laryngogram.

A

B

Fig. 1 5-24 Normal lateral laryn­ gogram.

c

Fig. 1 5-25 A, AP projection, B, Tomogram showing rounded soft tissue mass involving two thirds of left cord hanging down into subglottic larynx (arrows). C, On lateral projection this is best demonstrated with Valsalva's maneuver. 61

Thyroid Gland: Methods of Examination Radiographic examination of the thyroid gland is not performed regularly at most health care facil ities. The thyroid gland is effectively evaluated u ing computed tomography, nuclear medicine, or ultra­ sonography. The thyroid gland is enclosed within a capsule and is situated in the middle por­ tion of the neck where it surrounds the front and sides of the superior area of the trachea. The thyroid gland normally ex­ tends from the lower third of the thyroid cartil age inferiorly for a di stance of 2 inches (5 cm) to about the level of the first thoracic vertebra. The thyroid gland is subject to a variety of abnormalities. Enlargement, the most frequently ob­ served change in this gland, results in swelling, called a goiter, in the front as­ pect of the neck. The enlargement may be either diffuse or nodular, depending on the nature of the abnormality present. It may be confined to the neck, or a portion of the gland may protrude into the superior tho­ racic cavity behind the sternum, in which case it is called an intrathoracic, retroster­ nal, or substernal goiter. The normal thy­ roid gland is not discernible on AP projec­ tions of the neck, and only the narrow median portion, the isthmus, is visualized on lateral projections ( Figs. 1 5-26 and 1 5-27 ) .

62

Diffuse enlargement o f the thyroid gland usually requires no more than AP and lat­ eral projections of the neck and chest. These radiographs generally demonstrate any intrathoracic extension of the gland, any compression or displacement of the trachea by the enJarged gland, the presence of any calcium deposits, and the need for further evaluation. Following are some guidelines for the use of these projections: Adjust the patient to place the thyroid mass slightly tangent to the IR. Use the lateral projection of the neck to demonstrate intrathoracic extension of the goiter when the shoulders cannot otherwise be rotated posteriorly enough to clear the superior mediastinum. When nodular enlargement is present, obtain oblique studies of the neck. •

•

•

Fig. 1 5-26 AP and right lateral projections demonstrating benign suprasternal and sub­ sternal enlargement of thyroid gland. showing compression. narrowing. and displacement of trachea to right (arrows).

Fig. 1 5-27 Lateral projection showing cal­ cified hematoma of thyroid gland (arrows),

63

Pharynx and Larynx

AP PROJECTION Radiographic studies of the pharyngola­ ryngeal structures are made during breath­ i ng, phonation, stress maneuvers, and swallowing. To minimize the i ncidence of motion, the shortest possible exposure time must be used in the examinations. For the purpose of obtaining improved contrast on the AP projections, use of a grid is recommended.

Position of patient •

Except for tomographic studies, which require a recumbent body position (Fig. 1 5-28), place the patient i n the upright position, either seated or standi ng, whenever possible.

Position of part •

•

•

Image receptor: 8 x t o inches ( 1 8 X

•

24 cm) or 24 X 30 cm lengthwise •

• •

--- -

I,.

Center the midsagittal plane of the body to the midline of the vertical grid device. Ask the patient to sit or stand straight. If the standing position is used, have the patient distribute the weight of the body equal ly on the feet. Adjust the patient's shoulders to lie in the same horizontal plane to prevent ro­ tation of the head and neck and resul­ tant obliquity of the throat structures. Center the IR at the level of or j ust be­ low the laryngeal prominence. Extend the patient's head only enough to prevent the mandibular shadow from obscuring the laryngeal area. Shield gonads. Respiration: Obtain preliminary radi­ ographs (both AP and lateral) during the i nspiratory phase of quiet nasal breath­ ing to ensure that the throat passages are filled with air. To determine the opti­ mum time for the exposure, watch the breathing movements of the chest. Make the exposure just before the chest comes to rest at the end of one of its in­ spiratory expansions (Figs. 1 5-29 and 1 5-30).

�.... .... . �� .."...;

-- �-----

Fig. 1 5-28 AP pharynx and larynx with patient in supine position for tomography.

Fig. 1 5-29 AP pharynx and larynx during quiet breathing.

64

Fig. 1 5-30 Lateral pharynx and larynx showing polypoid mass of right false fold hanging into subglottic larynx (arrows).

Pharynx and Larynx

Central ray

Perpendicular to the laryngeal promi­ nence Additional studies

Further necessary studies of the pharynx and larynx are usually determined fl uoro­ scopically. These studies may be made at the fol lowing times: I . During the Valsalva's and/or modified Valsalva's stress maneuvers (Fig. 1 5-3 1 ). 2. At the height of the act of swallowing a bolus of I tablespoon of creamy barium sulfate suspension. The patient holds the barium sulfate bolus in the mouth until signaled and then swallows it in one movement. The patient is asked to refrain from swallowing again if a dou­ ble-contrast study is to be attempted. 3. During the modified Va!salva's maneu­ ver immediately after the barium swal­ low for double-contrast deli neation of the piriform recesses. 4. During phonation and/or with the larynx in the rest position after its opacification with an iodinated contrast medium.

Tomographic studies of the larynx are made during phonation of a high-pitched e-e-e. After these studies, one or more sec­ tional studies may be made at the selected level or levels with the larynx at rest (Figs. 1 5-32 and 1 5-33).

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Area from the superimposed mandible and base of the skull to the lung apices and superior mediastinum • No overlap of the laryngeal area by the mandible • No rotation of neck • Throat fi lled with air in preliminary studies • Radiographic density permitting visu­ al i zation of the pharyngol ary ngeal structures

Fig. 1 5-31 AP pharynx and larynx demonstrating Valsalva's maneuver.

Fig. 1 5-32 AP pharynx and larynx with tomogram showing poly­ poid laryngeal mass (arrows).

Fig. 1 5-33 AP pharynx and larynx. These tomograms demonstrate large cyst of left aryepiglottic fold and piriform recess (arrows).

65

Soft Palate, Pharynx, and Larynx

LATERAL PROJECTION R or L position Image receptor: 8 x 1 0 i nches ( 1 8 x 24 cm) lengthwise Position ot patient •

•

Ask the patient to sit or stand laterally before the vertical grid device. Adj ust the patient so that the coronal plane that passes through or j ust ante­ rior to the temporomandibular joints i s centered t o the midline o f the I R .

Central ray •

Procedure

Perpendicular to the l R, centering the lR ( I ) I inch ( 2 . 5 cm) below the level of the external acoustic (auditory) me­ atuses for demonstration of the na­ sopharynx and for cleft palate studies, (2) at the level of the mandibular angles for demonstration of the oropharynx, or ( 3 ) at the level of the laryngeal promi­ nence for demonstration of the larynx, laryngeal pharynx, and upper end of the esophagus (Fig. 1 5-34)

Preliminary studies of the pharyngolaryn­ geal structures are made during the in­ halation phase of quiet nasal breathing to ensure filling the passages with air ( Fig. 1 5-35).

Position ot part •

•

•

• •

Ask the patient to sit or stand straight, with the adj acent shoulder resting firmly against the stand for support. Adjust the body so that the midsagittal plane is parallel with the plane of the IR. Depress the shoulders as much as pos­ sible, and adj ust them to lie in the same transverse plane. If needed, have the patient clasp the hands in back to pos­ teriorly rotate the shoulders. Extend the patient's head slightly. Immobilize the head by having the pa­ tient look at an object in l ine with the visual axis. Fig. 1 5-34 Lateral pharynx and larynx.

Fig. 1 5-35 Lateral pharynx and larynx during normal breathing.

66

Soft Palate, Pharynx, and Larynx

According to the site and nature of the abnormality, further studies may be made. Each of the selected maneuvers must be explained to the patient and practiced j ust before actual use. The studies are obtained at one or more of the fol lowing: I . During phonation of specified vowel sounds for demonstration of the vocal cords and for cleft palate studies (Fig. 1 5-36) 2. During the Valsalva's maneuver to dis­

tend the subglottic larynx and trachea with air (Fig. 1 5-37) 3 . During the modified Valsalva's maneu­ ver to distend the supraglottic larynx and the laryngeal pharynx with air

4. At the height of the act of swallowing a bolus of I tablespoon of creamy bar­

ium sulfate suspension for demonstra­ tion of the pharyngeal structures 5. With the larynx at rest or during phonation after opaci fication of the structure with an iodinated medium 6. During the act of swallowing a tuft or pledget of cotton (or food) saturated with a barium sulfate suspension for demonstration of nonopaque foreign bodies located in the pharynx or upper esophagus

EVALUATION CRITERIA

The following should be clearly demon­ strated : • Soft tissue density of the pharyngola­ ryngeal structures • Area from the nasopharynx to the up­ permost part of the lungs in preliminary studies • Specific area of interest centered in de­ tajled examinations • No superimposition of the trachea by the shoulders • Closely superi mposed mandibular shadows • Throat fil led with air in prelimi nary studies

Hyoid bone Loryngeal structures

Trachea

Fig. 1 5-36 Lateral pharynx and larynx during phonation of e-e-e.

Fig. 1 5-37 Lateral pharynx and larynx during Valsalva 's maneuver.

67

16 •

Spleen

•

Biliary Tract

OUTLIN E

SUMMARY OF PROJ ECTIONS

PROJ ECTIONS,

POSITIONS,

& METHODS

Abdomen 82 86 88

•

Abdomen

AP

L lateral decubitus

Abdomen

lateral

R or L

Abdomen

lateral

R or L dorsal decubitus

allbladder

101

Biliary tract and

1 04

Biliary tract and alibiadder

1 04

Biliary tract and

1 06

Biliary tract and gallbladder

1 08

Intravenous cholan i

1 12

Postoperative cholangiography

allbladder raphy

PA PA oblique

LAO

lateral

R only

AP

R lateral decubitus

AP oblique

RPO

AP oblique

RPO

Icons in the Essential column indicate projections frequently performed in the United States and Canada. Students should be competent in these projections.

Digestive System

Peritoneum

The digestive system consists of the ali­ mentary tract (described in Chapter 1 7 ) and certain accessory organs that con­ tribute to the digestive process. The radiologically important accessory organs of the digestive system are the teeth, which serve to masticate the food; the salivary glands, which secrete fluid into the mouth for the sal ivation of food ; and the liver and pancreas, which secrete specialized digestive juices i nto the smal l intesti ne. The anatomy and positioning of the thoracic, oral, and cervical portions of the digestive system are described I n Chapters 1 0, 1 4, a n d 1 5 , respectively.

The abdominopelvic cavity consists of two parts: ( I ) a large superior portion, the abdominal cavity, and (2) a smaller infe­ rior part, the pelvic cavity. The abdominal cavity extends from the diaphragm to the superior aspect of the bony pelvis. The ab­ domi nal cavity contai ns the stomach, small and large intestines, liver, gallblad­ der, spleen, pancreas, and kidneys. The pelvic cavity lies within the margins of the bony pelvis and contains the rectum and sigmoid of the large intestine, the urinary bladder, and the reproductive organs.

Parietal peritoneum

Parietal peritoneum

Visceral peritoneum

The abdominopelvic cavity is enclosed in a double-walled seromembranous sac called the peritoneum. The outer portion of this ac, termed the parietal peritoneum, is in close contact with the abdominal wal l, the greater (false) pelvic wal l, and most of the undersurface of the diaphragm. The in­ ner port ion of the sac, known as the vis­ ceral peritoneum, is positioned over or around the contained organs and forms folds called the mesentery and omenta, which serve to support the viscera in posi­ tion. The space between the two layers of the peritoneum is cal led the peritoneal cavity and it contains serous fluid ( Fig. 1 6- 1 , A). These nonadhering peritoneum allows pelvic surgery to be performed without entry into the peritoneal cavity. The retroperitoneum is the cavity be­ hind the peritoneum. Organs such as the kidneys and pancreas lie in the retroperi­ toneum.

Visceral peritoneum

A

Liver

-I'f+-1f+t

-

Stomach

B

Peritoneal cavity -----I--HffRetroperitonenum Transverse colon Mesentary

Jl.Jll.J+.-It���

Diaphragm Liver. left lobe

---+��fIH��i2=z:�

Falciform ligament

Esophagus Stomach Spleen

Liver, right lobe

Omentum

Gall bladder

Jejunum _----It-l\IT4�1! Sigmoid colon

------'\\-\-�'="-==�:-WII_i\\ Urinary �\-\�::_� W bladder _ _

Ascending colon Ileum Appendix

�e:,?)):;;;��

Pancreas Transverse colon Descending colon Small intestine Urinary bladder

Fig. 1 6- 1 A, Lateral aspect of abdomen demonstrating the peritoneal sac and its com­ ponents. B, Anterior aspect of abdominal viscera in relation to surrounding structures. 71

Liver and Biliary System The liver. the largest gland in the body, is an irregularly wedge-shaped gland. I t is situated with its base on the right and its apex directed anteriorly and to the left ( Figs. 1 6- 1 and 1 6-2). The deepe t point of the l iver is the inferior aspect just above the right Iddney. The diaphrag­ matic surface of the l iver is convex and conform to the undersurface of the di­ aphragm. The visceral surface is concave and molded over the viscera on which it rests. Al most all of the right hypochon­ drium and a large part of the epigastrium are occupied by the l iver. The right por­ tion extends inferiorly into the right lat­ eral region as far as the fourth l umbar vertebra, and the left extremity extends across the left hypochondrium.

At the falciform ligament, the liver is divided into a large right lobe and a much smaller left lobe. Two minor lobes are lo­ cated on the medial side of the right lobe: the caudate lobe on the posterior surface and the quadrate lobe on the inferior sur­ face (Fig. 1 6-3). The hilum of the l iver, called the porta hepatis, is situated trans­ versely between the two minor lobes. The portal vein and the hepatic artery, both of which convey blood to the liver, enter the porta hepatis and branch out through the liver substance (see Fig. 1 6-3, C). The portal vein ends in the sinusoids, and the hepatic artery ends in capillaries that communicate with sinusoids. Thus, in addition to the usual arterial blood supply, the l iver receives blood from the portal system. The portal system, of which the portal vein is the main trunk, consists of the veins arising from the walls of the stomach, from the greater part of the intestinal tract

and the gallbladder, and from the pancreas and the spleen. The blood circulating through these organs is rich in nutrients and is carried to the liver for modification before being returned to the heart. The he­ patic veins convey the blood from the l iver sinusoids to the inferior vena cava. The l iver has numerous physiologic functions. The prim ary consideration from the radiographic standpoint is the formation of bile. The gland secretes bile at the rate of I to 3 pints C� to I '� L) each day. B i le, the channel of eli mination for the waste products of red blood cell de­ struction, is an excretion, as wel l a a se­ cretion. As a secretion, it is an i mportant aid in the emulsification and assimilation of fats. The bile is collected from the l iver cells by the ducts and either carried to the gal lbladder for temporary storage or poured directly into the duodenum through the common bile duct.

Parotid gland

Gallbladder --04-Biliary ducts Visceral surface of liver

Stomach �-- Spleen

�£dI!lJ-�-- Pancreas Large intestine

Appendix

Small intestine

Fig. 1 6-2 Alimentary tract and accessory organs. To demonstrate the position of the gall­ bladder in relation to the liver. the liver is shown with the inferior portion pulled anteriorly and superiorly. thus placing the liver in an atypical position. The true relationship of the liver and gallbladder is seen in Fig. 1 6- 1 . 72

The biliary, or excretory, system of the l iver consists of the bile ducts and gal l­ bladder ( Figs. 1 6-3 and 1 6-4). Beginning within the lobules as bile capi l l aries, the ducts unite to form larger and larger pas­ sages as they converge, fi nally forming two main ducts, one leading from each major lobe. The two main hepatic ducts emerge at the porta hepati and join to form the common hepatic duct, which in turn unites with the cystic duct to form the common bile duct. The hepatic and cystic ducts are each about I � inches ( 3 . 8 cm) in length. The common bile duct passes inferiorly for a distance of approx­ i mately 3 inches (7.6 cm). The common bile duct joins the pancreatic duct, and they enter together or side by side into an enlarged chamber known as the hepato­ pancreatic ampulla, or ampulla of Vater. The ampu lla opens into the descending portion of the duodenum. The distal end of the common bile duct is controlled by the choledochal sphincter as it enters the

duodenu m . The hepatopancreatic am­ pulla is control led by a circular muscle known as the sphincter of the hepatopan­ creatic ampuLLa, or sphincter of Oddi. During interdigestive periods the sphinc­ ter remains in a contracted state, thus routing most of the bile into the gallblad-

Liver

A

Gallbladder

Right lobe

Cystic duct

�i'��.iP��i"'Sii�

Hepatopancreatic ampulla

B

der for concentration and temporary stor­ age; during digestion it relaxes to permit the bile to flow from the liver and gal l­ bl adder i nto the duodenum. The he­ patopancreatic ampulla opens on an ele­ vation on the duodenal mucosa known as the major duodenal papilla.

Cut surface of liver

Pancreatic duct Pancreas

Inferior vena cava Common hepatiC duct Common bile duct

c

Liver

Cystic duct

vein Superior mesenteric vein

D

Common bile duct -+....-=::; .. ;;;; ;; ; Mucosa of duodenum Hepatopancreatic ampulla -t----'-....-I9:fSphincter of the hepatopancreatic ampulla

Pancreatic duct

Portal system

1 6-3 A, Visceral surface (inferoposterior aspect) of liver and gallbladder. B, Visceral (inferoposterior) surface of gall­ bladder and bile ducts. C, Portal system showing the hepatic artery and vein and other surrounding vessels. D, Detail of the drainage system into the duodenum. Fig.

Major duodenal papilla

73

The gallbladder is a thin-walled, more Pancreas and Spleen or less pear-shaped, musculomembranous The pancreas is an elongated gland situated sac with a capacity of approx i mately across the posterior abdominal wal l . 2 ounces. The gallbladder functions to Extending from the duodenum t o the spleen concentrate bile by absorption of the wa­ (Figs. 1 6-3 and 1 6-S), the pancreas is about ter content, to store bile during interdiges­ S Yz inches ( 1 4 cm) in length and consists of tive periods, and, by contraction of its a head, neck, body, and tail. The head, musculature, to evacuate the bile during which is the broadest portion of the organ, digestion. The muscular contraction of the extends inferiorly and is enclosed within gallbladder is activated by a hormone the curve of the duodenum at the level of called cholecystokinin. This hormone is the second or third lumbar vertebra. The secreted by the duodenal mucosa and re­ body and tail of the pancreas pass trans­ leased into the blood when fatty or acid versely behind the stomach and in front of chyme passes i nto the intestine. The organ the left kidney, with the narrow tail termi­ consists of a narrow neck that is continu­ nating near the spleen. The pancreas cannot ou with the cystic duct; a body or main be visualized on plain radiographic studies. portion; and a fundus, which is its broad The pancreas is both an exocrine and an lower portion. The gallbladder is usually endocrine gland. The exocrine cells of the lodged in a fossa on the visceral (inferior) pancreas are arranged in lobules with a surface of the right lobe of the liver, where highly ramified duct system. This exocrine it l ies in an oblique plane inferiorly and portion of the gland produces pancreatic anteriorly. Measuring about I inch (2.S juice, which acts on proteins, fats, and car­ cm) in width at its widest part and 3 to 4 bohydrates. The endocrine portion of the i nches (7.S to 1 0 cm) in length, the gall­ gland consists of clusters of islet cells, or bladder extends from the lower right mar­ islets of Langerhans, which are randomly gin of the porta hepatis to a variable dis­ distributed throughout the pancreas. Each tance below the anterior border of the islet consists of clusters of cells surrounding liver. The position of the gallbladder small groups of capillaries. These cells pro­ varies with body habitus, being high and duce the hormones insulin and glucagon, well away from the midl i ne in hyper­ which are responsible for sugar metabolism. sthenic persons and low and near the spine in asthenic individuals (see Fig. 1 6-4). The gal lbladder is sometimes embedded in the liver and frequently hangs free be­ low the inferior margin of the l iver.

y

y

y

Hypersthenic

Sthenic

Hyposthenic

The islet ceLIs do not communicate directly with the ducts but release their secretions di­ rectly into the blood through a rich capillary network. The digestive j uice secreted by the ex­ ocrine cells of the pancreas is conveyed into the pancreatic duct and from there i nto the duodenum. The pancreatic duct often unites with the common bile duct to form a si ngle passage via the hepatopan­ creatic ampul la, which opens directly i nto the descending duodenum. The spleen is included in this section only because of its location; it belongs to the lymphatic system. The spleen is a glandlike but ductless organ that functions to produce lymphocytes and to store and remove dead or dying red blood cells. The spleen is more or less bean-shaped and measures about S inches ( 1 3 cm) in length, 3 i nches (7.6 cm) in width, and I Y2 inches (3.8 cm) in thickness. Situated obliquely in the left upper quadrant, the spleen is j ust below the diaphragm and behind the stomach. It is in contact with the abdominal wall laterally, with the left suprarenal gland and left kidney medially, and with the left colic flexure of the colon inferiorly. The spleen is visualized both with and without contrast media.

Fig. 1 6-4 Gallbladder (green) position varies with body habitus. Note the extreme differ­ ence in position of the gallbladder between the hypersthenic and asthenic habitus. 74

y Asthenic

Duodenum

A

B

Righi side

Pancreas

Fig. 1 6-5 Sectional image of upper abdomen (viewed from the patient's feet upward), showirJg relationship of digestive system components, B, Axial CT image of the same area of the abdomen as A (From Kelley L: Sectional anatomy, St Louis, 1 997 Mosby,)

SUMMARY OF ANATOMY* Peritoneum

liver and biliary system

Pancreas and spleen

abdominopelvic cavity abdominal cavity pelvic cavity peritoneum parietal peritoneum visceral peritoneum mesentery omenta peritoneal cavity retroperitoneum

falciform ligament right lobe left lobe caudate lobe quadrate lobe porta hepatis hepatic artery portal vein hepatic veins hepatic ducts bile common hepatic duct cystic duct common bile duct hepatopancreatic ampulla sphincter of the hepa­ topancreatic ampulla major duodenal papilla gallbladder cystic duct

pancreas head body tail exocrine gland pancreatic juice endocrine gland islet cells pancreatic duct spleen

·See Addendum at the end of the volume for a summary of the changes in the anatomic terms that were introduced in the 9th edition

75

SUMMARY OF PATHOLOGY

76

Condition

Definition

Abdominal Aortic Aneurysm (AAA)

Localized dilatation of the abdominal aorta

Appendicitis

Inflammation of the appendix

Biliary Stenosis

Narrowing of the bile ducts

Bowel Obstruction

Blockage of the bowel lumen

Cholecystitis

Acute or chronic inflammation of the gallbladder

Choledocholithiasis

Calculus in the common bile duct

Cholelithiasis

The presence of gallstones

Ileus

Failure of bowel peristalsis

Metastases

Transfer of a cancerous lesion from one area to another

Pneumoperitoneum

Presence of air in the peritoneal cavity

Tumor

New tissue growth where cell proliferation is uncontrolled

Ulcerative Colitis

Recurrent disorder causing inflammatory ulceration in the colon

EXPOSURE TEC H N IQUE CHART ESSE NTIAL PROJ ECTIONS DIGESTIVE

Part

em

kVp'

AEC

SID

IR

Dose! (mrad)

21

75

200s

•• •

48"

35 x 43 em

1 85

PA

21

75

200s

48"

35 x 43 em

1 85

24

80

200s

•• • 0.0

AP (decubitus)

48"

35 x 43 em

300

Lateral

30

90

200s

0.0

48"

35 x 43 em

91 6

Lateral (decubitus)

30

95

200s

0.0

48"

35 x 43 em

1 040

21

70

0. 1 5

200s

30

48"

24 x 30 em

209

PA Oblique

25

70

0. 1 8

200s

36

48"

24 x 30 em

262

Lateral

30

85

0.33

200s

66

48"

24 x 30 em

1 1 00

AP (decubitus)

25

75

0. 1 8

200s

36

48 "

24 x 30 em

262

Abdomen*: AP

Biliary Tract & Gallbladder*: PA

tm

mA

SYSTEM

mAs

s.

Small focal spot. °kVp values are for a 3-phase 1 2-pulse generator. 'Relative doses for comparison use. All doses are skin entrance for average adult at cm indicated. 'Bucky. 1 6: 1 Grid. Screen/Film Speed 300.

77

,;'�:._

RAD I OGRAPHY

Abdominal Radiogra phic Procedures PRE LIMI NARY PROCEDURES AND POSITIONS Preparation

Careful prelimi nary preparation of the in­ testinal tract is important in radiologic in­ vestigations of the abdominal viscera. In the presence of nonacute conditions the preparation can consist of any combi na­ tion of controlled diet, laxative, and ene­ mas. The preparation ordered is generally determined by the medical facility in which the examination is to be performed. Although many patients referred for an examination of the abdomen are wel l enough to undergo routine preparation, a number have or are suspected of having ome condition that removes them from the "routine" classification even though they are not acutely i l l . In such patients, the referring physician is consulted as to the presumptive diagnosis, and the proce­ dure is varied a needed. Prelimi nary preparation i never administered to ill pa­ tients who are acutely i l l or have a condi­ tion such as visceral rupture or intestinal obstruction or perforation.

Exposure technique

Immobilization

In exami nations without a contrast medium, it is imperative to obtain maxi­ mum soft tissue differentiation throughout the different regions of the abdomen. Because of the wide range in the thickness of the abdomen and the delicate differences in physical density between the contained viscera, it is necessary to use a more criti­ cal exposure technique than is required to demonstrate the difference in density be­ tween an opacified organ and the structures adjacent to it. The exposure factors should therefore be adj usted to produce a radi­ ograph with moderate gray tones and less black-and-white contrast. If the kilovolt (peak) (kVp) is too high, the possibility of not demonstrating small or semiopaque gallstones increases (Fig. 1 6-6). Sharply defined outli nes of the psoas muscles, the lower border of the liver, the kidneys, the ribs, and the transver e processes of the lumbar vertebrae are the best criteria for judging the quality of an abdominal radiograph.

One of the prime requisites in abdominal examinations is the prevention of move­ ment, both voluntary and involuntary. The fol lowing steps are observed: To prevent muscle contraction caused by tenseness, adjust the patient in a comfortable position so that he or she can relax. Explain the breathing procedure, and make sure the patient understands ex­ actly what is expected. If needed, apply a compression band across the abdomen for immobilization but not compression. Do not start the exposure for I to 2 sec­ onds after the suspension of respiration to allow the patient to come to rest and involuntary movement of the viscera to ubside. Voluntary motion produces a blurred outline of the structures that do not have involuntary movement, such as "the l iver, psoas muscles, and the spine. I nvoluntary motion caused by peristalsis may produce either a localized or general ized haziness of the i mage. I nvoluntary contraction of the abdominal wall or the muscles around the spine may cause movement of the en­ tire abdominal area and produce general­ ized radiographic haziness. •

•

•

•

Fig. 1 6-6 AP abdomen showing proper positioning and collimation. 78

Radiographic projections

Radiography of the abdomen may include one or more radiographic projections. The most commonly performed is the supine AP projection, often called a KUB be­ cause it includes the kidneys, ureters, and bladder. Projections used to complement the supine AP may include an upright AP abdomen and/or an AP projection in the lateral decubitus position (the left lateral decubitus is most often preferred). Both radiographs are useful in assessing the ab­ domen in patients with visceroptosis (pro­ lapse or fal ling down of the abdomi nal vis­ cera) and in determining air-fluid levels. Other abdomi nal projections may include a lateral projection or a lateral projection in the supine (dorsal decubitus) body posi­ tion. Many institutions also obtain a PA chest radiograph to include the upper ab­ domen and diaphragm. The PA chest radi­ ograph is indicated because any air escap­ ing from the gastroi ntestinal tract into the peritoneal space rises to the highest level, usually j ust beneath the diaphragm.

PROJECTIONS Radiographs obtained to evaluate the pa­ tient's abdomen vary considerably depend­ ing on the institution and physician. For ex­ ample, some consider the preliminary evaluation radiograph to consist of only the AP (supine) projection. Others obtain two projections: a supine and an upright AP ab­ domen (often called a flat and an upright). A three-way or acute abdomen series may be requested to rule out free air and infec­ tions. The three projections usually include ( I ) an AP with the patient supine, (2) an AP with the patient upright, and (3) a PA chest. If the patient is unable to stand for the up­ right AP projection, the projection is per­ formed using the left lateraJ decubitus po­ sition. The PA chest projection can be used to detect free air that may accumulate un­ der the diaphragm. Positioning for radiographs of the ab­ domen is described in the fol low ing pages. ( For a description of positioning for the PA chest, see Chapter 1 0. )

Radiation Protection General radiation protection techniques must be used. Gonadal shielding is re­ quired in the following situations: I . If the gonads lie in close proximity (2 inches [ S c m ] ) to the primary x-ray field despite proper beam li mitation. 2. If the cli nical objectives of the exami­ nation will not be compromised . The concern is whether the use of gonadal shielding will cover an area of interest on the radiograph. 3. If the patient has a reasonable repro­ ductive potential. Whether gonad shielding is or is not used, close and accurate collimation is nec­ essary to limit the x-ray beam. In addition to reducing the amount of radiation expo­ sure to an unnecessary area, this practice also improves the quality of radiographs.

79

Abdomen

'" AP PROJECTION

Position of part •

Image receptor: 3 5

x 43 c m

lengthwise

•

Position of patient

•

•

For the AP abdomen, or K U B , projec­ tion, place the patient either in the supine or upright position. The supine position is preferred for most i nitial ex­ aminations of the abdomen.

•

•

Center the midsagittal plane of the body to the midline of the grid device. If the patient is upright, distribute the weight of the body equal ly on the feet. Place the patient's arms where they will not cast shadows on the image. With the patient supine, place a support under the knees to relieve strain. For the supine position, center the I R at the level of the i l iac crests and ensure that the pubic symphysis is included (Fig. 1 6-7).

•

•

•

•

•

•

For the upright position. center the IR 2 inches (5 cm) above the level of the il­ iac crests or high enough to include the diaphragm (Fig. 1 6-8). I f the bladder is to be included on the upright radiograph, center the I R at the level of the iliac crests. If a patient is too tall to i nclude the en­ tire pelvic area, obtain a second radi­ ograph to include the bladder on a 24 X 30 cm I R if needed. The 24 X 30 cm I R is placed crosswise and centered 2 t o 3 inches (5 to 7.6 cm) above the upper border of the pubic symphysis. I f needed, apply a compression band across the abdomen with moderate pressure for i mmobil ization. Shield gonads: Use local gonad shield­ i ng for examinations of male patients (not shown for i llustrative purposes). Respiration: Suspend at the end of ex­ piration so the abdominal organs are not compressed.

Central ray •

Fig. 1 6-7 AP abdomen. supine.

Fig. 1 6-8 AP abdomen. upright.

80

Perpendicular to the I R at the level of the i liac crests for the supine position and horizontal and 2 inches (5 cm) above the level of the iliac crests to include the di­ aphragm for the upright position

Abdomen

EVALUATION CRITERIA

Structures shown

An AP projection of the abdomen shows the size and shape of the liver, the spleen and the kidneys, and intraabdominal calci­ fications or evidence of tumor masses (Fig. 1 6-9). Additional examples of supine and upright abdomen projections are shown in Figs. 1 6- 1 5 and 1 6- 1 6.

The fol lowing should be clearly demon­ strated: • Area from the pubic symphysis to the upper abdomen. (Two radiographs may be needed if the patient is tal l . ) • Proper patient alignment is ensured by the following: o Centered vertebral column o Ribs, pelvis, and hips equidistant to the edge of the radiograph on both sides • No rotation of patient, as indicated by the fol lowing: o Spinous processes in the center of the lumbar vertebrae o Ischial spines of the pelvis symmet­ ric, if visible o Alae or wings of the ilia symmetric

•

•

• •

Soft tissue gray tones should demon­ strate the following: o Lateral abdominal wall and properi­ toneal fat layer o Psoa muscles, lower border of the l iver, and kidneys o Inferior ribs o Transverse processes of the lumbar vertebrae o Right or left marker visible but not lying over the abdominal contents Diaphragm without motion on upright abdomen examinations. (Crosswise J R placement is appropriate if the patient is very large. ) Density o n upright abdomen examina­ tion, similar to supine examination. Upright abdomen identified with an ap­ propriate marker.

B

A

Fig. 1 6-9 AP abdomen showing kidney shadows (dotted line). margin of liver (dashed line). and psoas muscles (dot-dash lines). 81

Abdomen

.. PA PROJECTION

.. AP PROJECTION

When the kidneys are not of primary in­ terest, the upright PA projection should be considered. Compared with the AP pro­ jection the PA projection of the abdomen greatly reduces patient gonadal dose.

o

Position of patient o

Image receptor: 35 x 43 cm length­

o

o

o

With the patient in the upright position, place the anterior abdomi nal surface in contact with the vertical grid device. Center the abdominal midline to the midline of the I R . Center the I R 2 inches (5 cm) above the level of the iliac crests (Fig. 1 6- lO), as previously described for the upright AP projection. The central ray, structures shown, and evaluation criteria are the same as for the upright AP projection.

o

o

o

o

If the patient is too i II to stand, place him or her in a lateral recumbent posi­ tion lying on a radiolucent pad on a transportation cart. Use a left lateral de­ cubitus position in most situations. If possible, have the patient lie on the side for several mi nutes before the ex­ posure to allow air to rise to its highest level within the abdomen. Place the patient's arms above the level of the diaphragm so that they are not projected over any abdominal contents. Flex the patient's knees sl ightly to pro­ vide stabil ization. Exercise care to ensure that the patient does not fall off the cart; if a cart is used, lock all wheels securely in position .

Fig. 1 6- 1 0 PA abdomen. upright position. This projection is sug­ gested for survey examination of the abdomen when the kidneys are not of primary interest. 82

o

Image receptor: 35 x 43 cm

wise Position of patient

Position of part

L lateral decubitus position

Upright

o

o o

Adjust the height of the vertical grid de­ vice so that the long axis of the I R is centered to the midsagittal plane. Position the patient so that the level of the iliac crests is centered to the IR. A slightly higher centering point, 2 inches (5 cm) above the i l iac crests, may be needed to ensure that the diaphragms are incl uded in the i mage (Fig. 1 6- 1 1 ). Adjust the patient to ensure that a true lateral position is attained. Shield gonads. Respiration: Suspend at the end of ex­ piration.

Central ray o

Directed horizontal and perpendicular to the midpoint of the IR

NOTE: A right lateral decubitus position i s of­ ten requested or it may be required when the patient cannot l ie on the left side.

Fig. 1 6- 1 1 AP abdomen, left lateral decubitus position

Abdomen

EVALUATION CRITERIA

Structures shown

In addition to showing the size and shape of the liver, spleen, and kidneys, the AP abdomen with the patient in the left decu­ bitus position is most valuable for demon­ strating air or fluid levels when an upright abdomen projection cannot be obtained (Fig. j 6- 1 2).

The following should be clearly demon­ strated: • Diaphragm without motion. • Both sides of the abdomen. I f this is not possible, do the following: o Elevate and demonstrate the side down when fluid is suspected. o Demonstrate the side up when free air is suspected. • Abdomi nal wal l, flank structures, and diaphragm. • No rotation of patient. • Proper identification visible, including patient side and marking to indicate which side is up.

Air-fluid interface Diaphragm

.=?-=----:-:-;-----�

Intestinal gas

Surgical clips

Crest of ilium Patient support

Fig. 1 6- 1 2 AP abdomen. left lateral decubitus position resulting in air outlined by the air­ fluid interface.

83

Abdomen

Abdominal sequencing

To demonstrate small amounts of intraperi­ toneal gas in acute abdomi nal cases, Miller'·2 recommended that the patient be kept in the left lateral position on a stretcher for 1 0 to 20 minutes before ab­ dominal radiographs were obtained. This position allows gas to rise into the area un­ der the right hemidiaphragm, where the image will not be superimposed by the gas­ tric gas bubble. If larger amounts of free air are present, many radiology departments suggest that the patient l ie on the side for a minimum of 5 minutes before the radi­ ograph is produced. Projections of the ab­ domen are then taken as follows:

•

•

•

•

•

Perform an AP or PA projection of the chest and upper abdomen with the pa­ tient in the left lateral decubitus position. Use the chest exposure technique for this radiograph (Fig. 1 6- 1 3) . Maintain the patient in the left lateral decubitus position while the patient is being moved onto a horizontally placed table. Tilt the table and patient to the upright position. Turn the patient to obtain AP or PA pro­ jections of the chest and abdomen (Figs. 1 6- 1 4 and 1 6- 1 5 ) . Return the table back to the horizontal position for a supine AP or PA projec­ tion of the abdomen (Fig. 1 6- 1 6) .

' Miller RE, Nelson SW: The roentgenologic demon­ stration of tiny amounts of free intraperitoneal gas: ex­ perimental and clinical studies, AJR 1 1 2:574, 1 97 1 . 2Miller RE: The technical approach to the acute ab­ domen, Semill Roenlgellol 8:267, 1 973.

Fig. 1 6- 1 3 Enlarged portion of a n A P abdomen left lateral decubitus position. i n a patient injected with 1 ml of air injected into the abdominal cavity.

84

Abdomen

Fig. 1 6- 1 4 Enlarged portion of an upright AP chest showing free air in same patient as in Fig. 1 6- 1 3.

Fig. 1 6- 1 5 AP abdomen, upright position, showing air-fluid levels (arrows) in intestine (same patient as in Fig. 1 6- 1 6).

Fig. 1 6- 1 6 AP abdomen. Supine study showing intestinal obstruc­ tion on same patient as in Fig. 1 6- 1 5.

85

Abdomen

.. LATERAL PROJECTION R or l position Image

receptor:

•

35

x 43 cm

lengthwise

Turn the patient to a lateral recumbent position on either the right or left side.

Position of port •

•

•

•

•

• •

Perpendicular to the IR and entering the midcoronal plane at the level of the il­ iac crest or 2 i nches (5 cm) above the i l­ iac crest if the diaphragm is i ncluded

Structures shown

Position of patient •

Central roy

Flex the patient's knees to a comfort­ able position, and adjust the body so that the midcoronal plane is centered to the midline of the grid. Place supports between the knees and the ankles. Flex the elbows, and place the hands under the patient's head (Fig. 1 6- 1 7). Center the IR at the level of the iliac crests or 2 inches (5 cm) above the crests to include the diaphragm. Place a compression band across the pelvis for stability if needed. ShieLd gonads. Respiration: Suspend at the end of ex­ piration.

A l ateral projection of the abdomen demonstrates the prevertebral space occu­ pied by the abdominal aorta, as well as any intraabdominal calcifications or tu­ mor masses ( Fig. 1 6- 1 8 ) . EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated : • Abdominal contents vi sible with soft tissue gray tones • No rotation of patient, i ndicated by the fol lowi ng: o Superimposed ilia o S uperi mposed l umbar vertebrae pedicles and open intervertebral foramina • As much of the remaining abdomen as possible when the diaphragm i s included

Fig. 1 6- 1 7 Right lateral abdomen.

86

Abdomen

Prevertebral space

Bowel gas

Fig. 1 6- 1 8 Right lateral abdomen.

87

Abdomen

.. LATERAL PROJECTION R or L dorsal decubitus position

•

Image receptor: 35 x 43 cm •

Position of patient •

•

•

When the patient cannot stand or l ie on the side, place the patient in the supine position on a transportation cart or other suitable support with the right or left side in contact with the vertical grid device. Place the patient's arms across the up­ per chest to ensure they are not pro­ jected over any abdominal contents, or place them behind the patient's head. Flex the patient's knees slightly to re­ l ieve strain on the back. Exercise care to ensure that the patient does not fal l from the cart or table; if a cart is used, lock all wheels securely in position.

Central ray

Position of part

• •

Adjust the height of the vertical grid de­ vice so that the long axis of the IR is centered to the midcoronal plane. Position the patient so that a point ap­ proxi mately 2 inches (5 cm) above the level of the i liac crests is centered to the IR (Fig. 1 6- 1 9). Adj ust the patient to make sure no rota­ tion from the supine position occurs. Shield gonads. Respiration: Suspend at the end of ex­ piration.

•

Directed horizontal and perpendicular to the center of the IR, entering the midcoronal plane 2 inches (5 cm) above the level of the i liac crests.

Fig. 1 6- 1 9 Lateral abdomen. left dorsal decubitus position.

88

Abdomen

COMPUTED RADIOGRAPHY

•

The higher kYp used for this projection requlres very close col li mation. Primary and cattered radiation reaching the I R phosphor may cause computer artifacts. Structures shown

The lateral projection of the abdomen is valuable in demonstrating the prevertebral space and is quite useful in determining aiI­ fluid levels in the abdomen (Fig. 1 6-20).

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Diaphragm without motion • Abdominal contents visible with soft tissue gray tones • Patient elevated so that entire abdomen is demonstrated

Gas filled colon Gas level in colon

Diaphragm

Posterior ribs Support elevating patient

_ _ _

Fig. 1 6-20 Lateral abdomen, left dorsal decubitus position, demonstrating a calcified aorta (arrows).

89

Abdominal Fistulae and Sinuses For radiographic demonstration of the ori­ gin and extent of fistulae (abnormal pas­ sages, usually between two internal or­ gans) and si nuses (abnormal channels leading to abscesses), the following steps are observed: Fill the tract with a radiopaque contrast medium, usuall y under fluoroscopic control .

o

o

o

o

o

o

o

Obtain right-angle projections. Oblique projections are occasionally required to demonstrate the full extent of a sinus tract. To explore fistulae and sinuse in the abdomi nal region, have the intestinal tract as free of gas and fecal material as possible. Unless the injection is made under flu­ oroscopic control, take a scout radi­ ograph of the abdomen to check the condition of the intestinal tract before beginning the examination. When more than one sinus opening is present, occlude each accessory open­ ing with sterile gauze packing to pre­ vent reflux of the contrast substance and identify every opening with a spe­ cific lead marker placed over the dress­ ing (Figs. 1 6-2 1 to 1 6-23). Dress and identify the pri mary sinus opening i n a imi lar manner if the catheter is removed after the injection. When a reflux of the contrast medium occurs, cleanse the skin thoroughly be­ fore making an exposure.

When fluoroscopy is not employed, place the patient in position for the first projection before the injection to pre­ vent drainage of the opaque sub tance by unnecessary movement. An i nitial radiograph is taken and evaluated be­ fore the examination is started or the patient's position i s changed. A modified gastrointestinal procedure is usual ly employed to detect the origin of colonic fistulae. An iodized oil is fre­ quently used in conjunction with a thin suspension of barium sulfate because the oil breaks up into clearly vi ible globules as soon as it reaches the watery barium suspension in the lumen of the intestine. For demonstration of a colonic fistula, the colon is filled with an enema consisting of the full amount of water but only about one-third the amount of barium ordi nari ly used. The physic ian then i njects an iodized oil through the fistulous tract and localizes its origin at the i ntestinal wall by the globulation of the oil . For demonstra­ tion of a fistula of the small intestine, the patient ingests a thin barium suspension, which the physician observes fluoroscopi­ cally or radiographically until it reaches the suspected region. The fistulous tract is then injected with the iodized oil. These examinations are performed using fluoro­ scopic control, with films being exposed as i ndicated.

o

Fig. 1 6-21 AP abdomen showing contrast­ filled sinus tract with a lead circular ring on body surface.

Fig. 1 6-22 Lateral abdomen showing sinus tract with a lead cir­ cular ring on body surface. 90

Fig. 1 6-23 Oblique abdomen, LPO position, showing fistula (arrow).

Biliary Tract and Gallbladder Several techniques can be used to exam­ ine the gallbladder and the biliary ductal system. In many institutions, sonography is the modality of choice. This section of the atlas discusses the radiographic tech­ niques currently available. Table 1 6- 1 lists some of the prefixes as­ soci ated with the bi l i ary system. Cholegraphy i s the general term for a ra­ diographic study of the biliary system. More specific terms can be used to de­ scribe the portion of the biliary system un­ der investigation. For example, cholecys­ tography is the radiographic investigation of the gallbladder, and cholangiography i s the rad iographic study o f the biliary ducts. Radiography of both the gallbladder and the biliary ducts is cholecystangiography or cholecystocholangiography. Cholecystography was developed by Graham, Cole, and Copher in 1 924 and 1 925 . 1 Oral cholegraphic contrast media were developed in the sequence listed in Table 1 6-2. Before Telepaque, the first of the three-iodi nated compounds, preopera­ tive vi sual ization of the biliary tract was li mited to the gal lbladder. In addition to permitting vi sual ization of the bile ducts, the three-iodinated compounds resulted i n a decrease in side effects. The contrast agent selected for use in the direct injection techniques to be dis­ cussed later (percutaneous transhepatic, operative, T-tube) may be any one of the water-soluble iodi nated compounds em­ ployed for intravenous urography. 'Graham EA, Cole W H , Copher G H : Chole­ cystography: the use of sodium tetraiodophenolph­ thalein, JAMA 84: 1 1 75. 1 925.

Digestive System Projections Removed­ Ninth Edition Advances in nuclear medicine, diagnostic sonography, computed tomography (CT), and magnetic resonance i maging ( M R I ) have virtual ly elimi nated abdominal pro­ jections of the liver and spleen. Previous editions of the atlas, including the eighth edition, described the fol lowing three pro­ jections :

Digestive System Projections Removed­ Tenth Edition •

Operative Pancreatography

Liver and spleen •

AP projection

Liver •

PA axial projections: Benassi method

Spleen •

AP oblique projection, LPO position

TABLE 16-1 Bil iary system combining forms

Root forms chole-

Meaning Relationship with bile

cysto­

Bag or sac

choledocho­

Common bile duct

cholangio­

Bile ducts

cholecyst-

Gallbladder

TABLE 16-2 Oral cholegra phic contrast media

Contrast media

Visualization

Two-iodinated compounds 1 924-1 925

Tetrabromophenolphthalein

Gallbladder

sodium 1 940 1 944

Tetraiodophenolphthalein Priodax

Gallbladder

Monophen

Gallbladder

Gallbladder

Three-iodinated compounds 1 949

1 952

1 960

1 962

lopanoic acid (Telepaque) Teridax

Gallbladder and ducts Gallbladder and ducts

Biloptin

Gallbladder and ducts

Ipodate calcium

Gallbladder and ducts

or sodium (Oragrafin) Bilopaque

Gallbladder and ducts

Six-iodinated compounds 1 952- 1 953 1 956

Biligrafin forte

Gallbladder and ducts

Cholografin

Gallbladder and ducts

Duografin (Cholografin

Gallbladder and ducts

methylglucamine

Urinary tract

plus Renografin)

91

The radiographic study of the biliary system requires the introduction of a con­ trast medium. Routes of administration are as follows : I . B y mouth-oral (Fig. 1 6-24) 2. By injection into a vein in a single bo­ lus or by drip infu ion-intravenous (Fig. 1 6-25)

Fig. 1 6-24 Oral cholecystogram.

92

3 . By direct i njection i nto the ducts­

percutaneous transhepatic cholan­ giography ( PTC) (Fig. 1 6-26), during bil iary tract surgery (operative or i m­ mediate) (Fig. 1 6-27), or through an indwelling drainage tube, termed a T-tube (postoperative or delayed) (Fig. 1 6-28)

Fig. 1 6-25 Intravenous cholangiogram showing stones in com­ mon bile duct (arrows).

Each technique of examination i s named according t o the route o f entry of the medium (i tal icized in the preceding l ist) and the portion of the biliary tract examined. Contrast medium can be delivered to the l iver by the oral or venous route be­ cause of the double blood supply to this organ. When given by mouth, the contrast medium is absorbed through the intestines and carried to the l iver through the portal vein. Contrast medium administered i n­ travenously is most common ly injected into one of the antecubital veins and thus passes through the heart and i nto the arte­ rial circulation. The contrast agent circu­ lates to the l iver via the hepatic artery and the portal vein. In the hepatic cells the con­ trast substance is biochemically changed and then excreted with the bile and con­ veyed to the gallbladder by the system of ducts. The contrast-carrying bile is stored and concentrated in the gallbladder, where it becomes radiopaque. Fig. 1 6-26 PTe examination.

Fig. 1 6-27 Operative cholangiogram.

Fig. 1 6-28 Postoperative cholangiogram, performed with a T-tube, showing retained stone (arrow).

93

EVALUATION OF BILIARY TRACT Indications

Biliary tract examjnations are performed to determine the following: Function of the liver-its ability to re­ move the contra t medjum from the bloodstream and excrete it with the bile Patency and condit jon of the biliary ducts Concentrating and emptying power of the gallbladder •

•

•

The greatest number of biliary tract ex­ ami nations are probably performed to search for gallstones. Calculi, or stones, formed in the biliary tract vary widely i n composition, size, and shape. Calcium­ containing deposi ts, either as soli tary cal­ culi or in the form of rrulk of calcium, can be readily detected on radiographs ( Fig. 1 6-29).

Technical requirements

For optimal technical quality, use the fol­ lowing guidelines: Ensure that the focal spot of the x-ray tube is small and in good condition. Ensure that the intensifying screens are clean and i n perfect contact. Ensure that the grid is in perfect operat­ ing condition. Closely col l imate the area of patient ir­ radiation. Make the patient comfortable to de­ crease the risk of motion. Stabilize elevated parts, and place radi­ olucent pads under pressure points. •

•

•

•

•

•

Fig. 1 6-29 Opacified gallbladder with radiopaque stones.

94

•

•

•

•

Employ immobilization with a broad compression band to aid in the control of movement if needed. Teach the patient to relax and to sus­ pend respiration duri ng the exposures. U e a short exposure time to eliminate blurring of the gallbladder and ducts as a result of vibratory movement caused by peristaltic action in the adjacent seg­ ments of the i ntestine. Adjust the exposure factors to produce maximum soft tissue differentiation (70 to 80 kYp is recommended). The i mage mu t show a sharp outl i ne of the lower border of the l iver, the right kidney, and the margin of the right psoas muscle, as well as a degree of intrastructural detail of the i ncluded bony parts.

•

•

•

•

Ensure that the scout radiograph of pa­ tients of an asthenic body habitus is dark enough to demonstrate the shadow of the gallbladder through the vertebral shadow. Make exposures at the end of expiration because this phase of respiration places the patient under less strain. Do not ask the patient either to expire or to inspire to the point of strain be­ cause spasmodic contraction of the ab­ dominal muscles w i l l occur. Give the breathing i nstructions carefully.

According to the body habitus of the pa­ tient and the degree of body fat present, the gallbladder moves laterally and superiorly I to 3 inches (2.5 to 7.6 cm) on full expiration and medially and inferiorly I to 3 inches (2.5 to 7.6 cm) on ful l inspiration ( Figs. 1 630 and 1 6-3 1 ). This information should be taken into account when the gallbladder im­ age on the scout radiograph is partially ob­ scured by the rib or by small amounts of gas. Cholecystograrns made at the end of inspiration, should be so marked.

Eleventh rib L1 Gallbladder

Gas in colon

Gallbladder L3

Fig. 1 6-30 AP gallbladder position during suspended expiration.

Fig. 1 6-31 AP gallbladder position during suspended inspi­ ration (same patient as in Fig, 1 6-30).

95

ORAL CHOLECYSTOGRAPHY

Instructions to patient

Preparation of intestinal tract

Indications and contraindications

Before OCG is performed, the fol lowing steps are observed: To secure full cooperation from the pa­ tient, explain the purpose of the prelim­ i nary preparation and the procedure to be followed. Tel l the patient the approxi mate lime required for the examination, allowing for the possibility of delay if the colon requires further cleansing or the empty­ ing time of the gallbladder is delayed. Give the patient clearly printed instruc­ tions covering ( l ) the preliminary preparation of the intestinal tract, (2) the preliminary diet, (3) the exact lime to ingest the oral medium, (4) the avoid­ ance of laxatives for 24 hours before the ingestion or injection of the medium, (5) the avoidance of all food, both solid and l iquid, after receiving an oral medium (water may be taken as desired before the oral examination), and (6) the time to report for the examination. When the patient reports for the exami­ nation, ask the patient how each step of the preparation procedure was fol lowed. For the oral technique, ask the patient whether any reaction such as vomiting or diarrhea occurred. Vomiting may be important if it occurs within 2 hours af­ ter i ngestion of the contrast medium. M i ld catharsis may do no harm, but di­ arrhea can result i n egestion of a major­ ity of the contrast substance, so that only a faint shadow, if any, of tPle gall­ bladder is visualized. Because prolonged fasting causes the formation of gas, as well as possible headache, give the patient an early­ morning appointment if possible.

M uch of the success of biliary lract exam­ i nations depends on attaining a clear i m­ age of the right upper quadrant of the ab­ domen (Fig. 1 6-32). In some patients a scout radiograph may be taken on the day before OCG. This radiograph serves a dual purpose: ( I ) assessment of bowel fe­ cal content to determine the extent of cleansing enemas required and (2) identi­ fication of small radiopaque stones that might otherwise be camouflaged by the contrast medium (Fig. \ 6-33). B ased on the scout radiograph the bowel content may be judged to be l ight to moderate so that it can be eliminated with one or two cleansi ng enemas. Heavy bowel content may require a laxative. Often, no preparation is needed. If used, laxatives are administered 24 hours before the ingestion or injection of a contrast agent to alI ow irritation of the intestinal mucosa to subside and, in the oral tech­ nique, to prevent egestion of the contrast medium with the fecal material .

Hundreds of thousands of people in the United States are evaluated or hospitalized each year for symptoms related to gallblad­ der disease. The most common radiographic procedure used to study the gallbladder is ultrasound. However, oral cholecystogra­ phy, the oral administration of contrast medium, continues in very limited use. Oral cholecystography (OCC) can be used to demonstrate a number of abnormal condi­ tions. OCG is frequently used because the oral contrast medium currently available is generally well tolerated and permits satis­ factory visualization of the extrahepatic bile ducts, as well as the gallbladder in a large percentage of patients examined. Before OCG is performed, the patient's allergic response to iodine compounds should be determined. OCG is generally contraindicated for patients with vomiting or diarrhea, pyloric obstruction, malab­ sorption syndrome, severe jaundice, liver dysfunction, hepatocellular disease, or hy­ persensitivity to iodinated contrast media.

•

•

•

•

•

•

96

Preliminary diet

Medical opinion varies on the subject of the preliminary diet. Some physicians believe that patients should be given a noon meal rich in simple fats on the day before the ex­ amination. This fat causes the gallbladder to contract; theoretically, the contrast-filled bile will then be more concentrated and clearly visible when OCG is performed. However, all medical personnel agree that patients should receive a fat-free evening meal to prevent the gallbladder from contracting and expel l ing the opaci­ fied bile. B reakfast is usuall y w ithheld i n all techniques. I n many institutions the OCG is often scheduled to be performed at the same time as an upper gastroin­ testinal exami nation. In this situation the patient is kept NPO (non per os; i.e., nothing taken i n through the mouth) un­ til the completion of both procedures. On the day of the examination, the oral cholecystogram is performed before the gastrointesti nal procedure.

Contrast administration

The contrast medium available for OCG is normally given to the patient i n a si ngle dose approxi mately 2 to 3 hours after the evening meal on the night before the ex­ amination. The usual single dose of 3 g is administered in the form of four to six tablets. B reakfast is usually withheld on the morning of the procedure. The contrast media used in oral chole­ cystography differ in their rate of absorp­ tion and l iberation i nto the portal blood­ stream. The absorption time varies from 1 0 to 1 2 hours for most present-day oral agents. The administration of the contrast agent is scheduled to allow enough time for maximum concentration of the con­ trast agent in the gallbladder. An excep­ tion is ipodate calcium, whjch is rapidly absorbed and allows visualization of the biliary ducts in an average of 1 .5 hours and visual ization of the gallbladder in 3 to 4 hours. Fig. 1 6-32 AP abdomen demonstrating prepared intestinal tract.

Fig. 1 6-33 AP abdomen demonstrating unprepared intestinal tract.

97

Scout radiographs

Patient instructions and preparation

To ensure that the contrast material was absorbed and concentrated in the gallblad­ der, one or more preliminary radiographs are often obtained. The decision to con­ tinue OCG is frequently based on whether the gal lbladder is visual ized on scout radi­ ographs and, if so, how wel l . The scout radiographs may be taken with the patient supine or prone. The prone position is generally preferred be­ cause it places the structures of the biliary system c loser to the I R .

validation

Before OCG is performed, the fol lowing steps are observed: Ensure that the patient has not had a cholecystectomy. If the gal lbladder has been removed, there is no reason to continue the procedure. When the patient reports for the proce­ dure, determine that each step of the preparation was followed.

•

•

•

•

•

•

98

Ask the patient if the contrast medium was administered and if any reaction such as vomiting or diarrhea occurred. Vomiting may be important if it occurs within 2 hours after i ngestion of the contrast medium. M i ld catharsis may do no harm, but diarrhea can result i n egestion o f most o f the contrast sub­ stance so that only a faint shadow, if any, of the gallbladder is v isualized. Determi ne whether the patient has re­ mained NPO. If the patient has correctly fol lowed the preparation, discuss the procedure with the patient. Tak i ng the time to review the procedure and answer any ques­ tions will gain the patient's respect and cooperation. Once the patient understands the proce­ dure, have the patient change i nto an examination gow n if not properly dressed.

Inspection of scout radiographs

As soon as the scout radiographs are available, they are carefully i nspected for the presence or absence of the gal lbladder ( Fig. 1 6-34). If contrast medium is pres­ ent, it is important to determine ( I ) whether the concentration of the contrast medium is sufficient for adequate vi ual­ ization, (2) the exact location of the organ, and ( 3 ) whether a change in the exposure factors is needed for proper demonstration of the organ.

When the gallbladder is not visualized, the entire abdomen should be evaluated if that procedure has not already been per­ formed. A 35 X 43 cm ( 1 4 X 1 7 i nch) scout radiograph is recommended to eval­ uate the patient for possible transposition of the abdomi nal organs and to check the i l iac fossa of patients with an asthenic body habitus. It is also possible that the gallbladder may be obscured by fecal ma­ terial in the colon. If such is the case, it may be necessary to administer an enema to clean the colon to the region of the right col ic flexure. It may be necessary to ques­ tion the patient again about the prepara­ tion. I t is possible that the patient did not fast or did not take all of the contrast medium.

Fig. 1 6-34 Normal AP gallbladder.

99

Fatty m eal

Postprocedure instructions

In the earlier years of radiology, patients were often given a fatty meal after satis­ factory visualization of the gallbladder. The fatty meal consisted of a commer­ cially available bar, eggs and milk, or eggnog. The meal caused the gallbladder to contract, and additional diagnostic i n­ formation was seldom obtained (Figs. 1 635 and 1 6-36). An injection of the hor­ mone cholecystokinin will also cause the gallbladder to contract. The fatty meal is seldom used today because of the diag­ nostic capability of u ltrasonography.

Once the gallbladder has been adequately vi­ sualized, the patient can go home or return to the hospital room. Currently available con­ trast material is eliminated mainly through the alimentary canal. The patient should be instructed to eat and drink normally.

Cystic duct Common bile duct

Gallbladder

Fig. 1 6-35 PA oblique gallbladder. LAO position. before fatty meal.

100

Fig. 1 6-36 PA oblique gallbladder. LAO position. after a fatty meal in the same patient as in Fig. 1 6-35.

Biliary Tract and Gallbladder

'" PA PROJECTION •

Image receptor: 24 x 30 cm for

scout radiograph, 8 X 1 0 i nches ( 1 8 X 24 cm) for subsequent exposures Position of patient Prone •

•

Place the patient in the prone position with a pillow under the head. I f the patient is thin, place the pil low lengthwise and adjust it so that it ex­ tends inferiorly as far as the trans­ mami llary l i ne or a little below it.

•

Upright position

Central ray

Adjust the body so that the previously localized gallbladder is centered to the midli ne of the grid ( Fig. 1 6-38). Elevate the gallbladder to (or almost to) the location it assumed in the prone po­ sition by i nstructing the patient to fully extend the arms. Otherwise, depending on the habitus of the patient, center the I R 2 to 4 i nches (5 to 1 0 cm) below the prone level to allow for the change i n gallbladder position. The remainder of the procedure is the same as for the prone position.

•

Perpendicular and centered to the gall­ bladder at a level appropriate to the pa­ tient's body habitus

Position of part Prone •

•

•

•

•

•

•

• •

Adj ust the patient's body so that the right side of the abdomen is centered to the midl i ne of the grid. Rest the patient's left cheek on the pil­ low to rotate the vertebrae slightly to­ ward the left side. Flex the patient's right elbow, and ad­ j ust the arm i n a comfortable position. I f necessary, place the left arm along­ side the body. Elevate the patient's ankles to relieve pressure on the toes. Center the IR according to the body habitus of the patient ( Fig. 1 6-37). If the patient has pendulous breasts, have her spread the breasts superiorly and laterally to ensure that the gal lblad­ der region is c leared. I mmobi l i ze the abdomen with a com­ pression band if necessary. ShieLd gonads. Respiration: Suspend respiration at the end of expiration. Watch for an indication of tenseness, and allow about 2 seconds to elapse after the cessation of respiration before making the exposure. This interval pennits peristaltic action to subside and gives the patient time to relax.

Fig. 1 6-37 PA gallbladder.

Fig. 1 6-38 PA gallbladder. upright position.

101

Biliary Tract and Gallbladder

Structures shown

The upright PA projection presents a somewhat axial representation of the opacified gallbladder. The foreshortening in the PA projection is caused by the angle between the long axis of the obl iquely placed gallbladder and the plane of the IR. The degree of angulation and conse­ quently the amount of foreshortening vary according to body habitus and are i nflu­ enced by body position, bei ng less in the upright position ( Figs. 1 6-39 and 1 6-40).

Fig. 1 6-39 PA gallbladder: hypersthenic patient. Note almost hor­ izontal position of gallbladder (see Fig. 1 6-4).

1 02

Fig. 1 6-40 PA gallbladder: asthenic patient.

Biliary Tract and Gallbladder

EVALUATION CRITERIA

The fol low ing should be clearly demon­ strated: • Entire gallbladder and area of the cystic duct • Gallbladder with a short scale of contrast • No motion visible on the gal lbladder • No rotation of patient • In upright position, centering that is lower and more medial to i nclude entire gal lbladder • Compensation for abdomi nal thickness in the upright position so that density is simi lar to that in the recumbent position • I mproved visibi lity in the upright posi­ tion if the gal lbladder was superim­ posed by bowel contents in the recum­ bent position • Upright position identified with an ap­ propriate marker

103

Biliary Tract and Gallbladder

.. ..

PA OBLIQUE PROJECTION LAO position

LATERAL PROJECTION

Position of part •

R lateral position Image receptor: 8 x 1 0 i nches ( 1 8

x 24 cm) lengthwise Position of patient •

Place the patient in the recumbent posi­ tion for oblique and lateral projections of the gallbladder.

•

•

•

•

•

The degree of rotation necessary for satisfactory demonstration of the gal l­ bladder depends on the location of the organ in reference to the vertebrae (thin subjects require more rotation than do heavier patients), the angulation of the long axis of the organ, and whether the right colic flexure is clear. With the patient in the prone position, elevate the right side to the desired de­ gree of obliquity ( 1 5 to 40 degrees). I nstruct the patient to support the body on flexed knee and elbow. Adjust the patient's body to center the previously localized gal lbladder to the midline of the grid. Place a foam sponge against the anterior surface of the abdomen (Fig. 1 6-4 1 ).

Fig. 1 6-41 PA oblique gallbladder. LAO position.

104

R lateral position

LAO position

•

• •

The patient l ies on the right side, and the right lateral position is used to dif­ ferentiate gallstones from renal stones or calcified mesenteric lymph nodes if needed. The lateral position is also re­ quired to separate the superimposition of the gallbladder and the vertebrae i n exceptionally t h i n patients and t o place the long axis of a transversely placed gallbladder parallel with the plane of the I R . Center the patient t o the I R a t the point where the gal lbladder has been previ­ ously localized (Fig. 1 6-42). ShieLd gonads. Respiration: Suspend at the end of ex­ piration unless the scout radiograph i n­ dicates otherwise.

Fig. 1 6-42 Right lateral gallbladder.

Biliary Tract and Gallbladder

EVALUATION CRITERIA

Central ray •

Perpendicular to the midpoint of the I R a t a level appropriate for the body habi­ tus of the patient for both the oblique and lateral projections

Structures shown

The oblique and lateral projections show the opacified gal lbladder free from self­ superi mposition or foreshorten i ng and from the structures adjacent to the gaI l­ bladder ( Figs. 1 6-43 to 1 6-45 ).

•

The fol lowing should be clearly demon­ strated: • Entire gallbladder and area of the cystic duct • Gallbladder with a short scale of con­ trast • No motion visible on the gall bladder

Fig. 1 6-43 PA oblique gallbladder, LAO position.

•

I mproved visibil ity in the oblique pro­ jection if the gallbladder was superim­ posed over bowel contents or bony shadows in other projections Compensation for increased thickness in lateral projection so that density is similar to that in other projections

Fig, 1 6-44 PA gallbladder in the same patient as in Fig. 1 6-55.

Fig. 1 6-45 Right lateral gallbladder demonstrating stones (arrows). 1 05

Biliary Tract and Gallbladder

.. AP PROJECTION R lateral decubitus position The right lateral decubitus body position for demonstration of the gallbladder was developed by Whelan. I Image receptor: 8 x 1 0 i nches ( 1 8 x 24 em) or 24 X 30 em placed vertically

•

•

•

Place the patient on the right side with the body elevated 2 to 3 i nches ( 5 to 7.6 cm) on a suitable radiolucent support to center the gallbladder region to the ver­ tical ly placed I R .

Central ray •

Position of patient

Structures shown

Position of part

Directed horizontally to enter the local­ ized area of the gallbladder ( Fig. 1 6-46)

The right lateral decubitus and upright po­ sitions are used to demonsu'ate stones that are heavier than bile and that are too smal l to be visible other than when accumulated in the dependent portion of the gal lblad­ der. These positions are also used to demonstrate stones that are lighter than bile and that are visualized only by strati­ fication (Fig. 1 6-47).

Place the patient in the lateral recum­ bent position on a stretcher or movable table in front of a vertical grid device. Exercise care to ensure that the patient does not fal l off the cart; lock aLI wheels of the cart securely in position.

'Whelan F J : Special cholecystographic technique, Xray Techllol 1 9:230, 1 948.

Fig. 1 6-46 A P gallbladder. right lateral decubitus position.

1 06

Biliary Tract and Gallbladder

NOTE: The right lateral decubitus position has the further advantage of permitting the gall­ bladder to gravitate toward the dependent right side, where it will lie below any adjacent gas­ containing loops of the intestine and away from bony superimposition when it occupies a low and/or medial position. The decubitus po­ sition is also used when patients cannot stand for an upright PA or AP projection.

EVALUATION CRITERIA

The fol lowi ng should be clearly demon­ strated: • Entire gallbladder and area of the cystic dUCl • Gallbladder with a short scaJe of contrast • 0 motion visible on the gal lbladder • Vertebrae visible (if i ncluded), indicat­ i ng that the patient was not rotated • Gallbladder lying below any gas • Decubitus marker

Air in bowel

Iliac crest

Gallbladder

Fig. 1 6-47 AP gallbladder, right lateral decubitus position.

1 07

Biliary Tract and Gallbladder

I NTRAVENOUS CHOLANGIOGRAPHY Intravenous cholangiography (IVe) is sel­ dom performed because of a relatively higher incidence of reactions to the con­ trast medium and the avai labil i ty of other diagnostic procedures. More complete de­ scriptions of the rvc are provided in ear­ l ier editions of this atlas. When used, l VC is employed to i nves­ tigate the bil iary ducts of cholecystec­ tomized patients. It is also used to investi­ gate the biliary ducts and gallbladder of noncholecystectomized patients when these structures are not visualized by OCG and when, because of vomiti ng or diarrhea, a patient cannot retain the orally administered medium long enough for its absorption. In cases of nonvisualization, immediately i nstituting the intravenous procedure may save ti me for the radiology department and the patient as well as spare the patient the rigors of having the intestinal tract prepared again .

Fig. 1 6-48 AP oblique, RPO position, showing biliary duct (dots).

1 08

Position of patient

The following steps are observed: Place the patient in the supine position for a preliminary radiograph of the ab­ domen. Place the patient in the RPO position ( 1 5 to 40 degrees) for an AP oblique projec­ tion of the biliary ducts (Figs. 1 6-48 and 1 6-49). Obtain a scout (localization) radiograph and/or tomogram ( Fig. 1 6-50) to check for centering and exposure factors. Advise the patient that a hot flush may occur when the contrast medium is in­ jected. Timed from the completion of the i n­ jection, duct studies are ordinari ly ob­ tained at 1 0-minute intervals until satis­ factory visual ization is obtai ned. Maximum opaci fication usua l l y re­ quires 30 to 40 minutes. •

•

•

•

•

Fig. 1 6-49 AP oblique biliary duct, RPO position, 1 0 minutes after injection of contrast medium.

Biliary Tract and Gallbladder

Contraindications

I ntravenous cholangiography is not gener­ ally i ndicated for patients who have l iver disease or for those whose biliary ducts are not i ntact. The probability of obtaining radiographs of diagnostic value greatly decreases when the patient's bil irubin is i ncreasing or when it exceeds 2 mg/dl. I n cases o f obstructive jaundice and post­ cholecystectomy, ultrasonography has be­ come the preferred technique for demon­ strating the biliary system.

Fig. 1 6-50 AP oblique biliary duct tomogram at l l -cm level, RPO position, showing duct (dots).

1 09

Biliary Tract and Gallbladder

PERCUTANEOUS TRANSHEPATIC CHOLANGIOGRAPHY Percutaneous transhepatic cholangiogra­ phy ( PTC ) I is another technique employed for preoperative radiologic examination of the biliary tract. This technique i used for patients with j aundice when the ductal system has been shown to be dilated by CT or u ltrasonography but the cause of the obstruction is unclear. The perfor­ mance of thi examjnation has greatly in­ creased because of the availabi lity of the Chiba ("skinny") needle. In addition, PTC is often used to place a drainage catheter for the treatment of obstructive jaundice. When a drai nage catheter is used, both di­ agnostic and drai nage techniques are per­ formed at the same time. ' Evans JA et al: Percutaneous transhepatic cholan­ giography. Radiology 78:362. 1 962.

Fig. 1 6-51 PTC with Chiba needle (arrow) in position showing di­ lated biliary ducts.

Fig. 1 6-52 PTC demonstrating obstruction stone at ampulla (ar­ row).

1 10

Fig. 1 6-53 PTC demonstrating stenosis (arrow) of common he­ patic duct caused by trauma.

Biliary Tract and Gallbladder

PTC is performed by placing the pa­ tient on the radiographic table in the supine position. The patient's right side is surgically prepared and appropriately draped. After a local anesthetic is admin­ istered, the Chiba needle is held parallel to the floor and insetted through the right lat­ eral intercostal space and advanced to­ ward the liver hilum. The stylet of the nee­ dle is withdrawn, and a syringe fil led with contrast medium is attached to the needle. U nder fl uoroscopic control, the needle is slowly wi thdrawn until the contrast medium is seen to fill the biliary ducts. In most i nstances the biliary tree is readily located because the ducts are generally di­ lated. After the biliary ducts are fi l led, the needle is completely withdrawn and serial or spot AP projections of the biliary area are taken ( Figs. 1 6-5 1 to 1 6-53 ).

BI LIARY DRAINAGE PROCEDURE AND STONE EXTRACTION If dilated biliary ducts are identified by CT, PTC, or ultrasonography, the radiolo­ gist, after consultation with the referri ng physician, may elect to place a drainage catheter in the biliary duct . 1 .2 A needle larger than the Chiba needle used in the PTC procedure is i nserted through the lat­ eral abdominal wall and into the biliary duct. A guide wire is then passed through the lumen of the needle, and the needle is removed . Once the catheter is passed over the guide wire, the wire is then removed, leaving the catheter in place.

The catheter can be left in place for pro­ longed drainage, or it can be used for at­ tempts to extract retained stones if they are identified. Retained stones are extracted using a wire basket and a small balloon catheter under fluoroscopic control. This extraction procedure is usual ly attempted after the catheter has been in place for some time ( Figs. 1 6-54 and 1 6-55).

I Molnar W, Stockum AE: Relief of obstructive jaun­ dice through percutaneous transhepalic catheter-a new therapeutic method. AJR 1 22 : 356. 1 974. 'Hardy CH, Messmer JM. Crawley LC: Percutaneous transhepatic biliary drainage, Radiol Technol 56:8.

1 984.

Right hepatic duct

Catheter

Drainage catheter in common bile duct Contrast "spill" into duodenum

Tip of catheter

Fig. 1 6-54 PTe with drainage catheter in place.

Fig. 1 6-55 Post PTe image showing wire basket (arrow) around retained stone.

111

Postoperative Cholangiography Postoperative, delayed, and T-tube cholan­ giography are radiologic terms applied to the bil iary tract examination that is per­ formed by way of the T-shaped tube left in the common bile duct for postoperative drainage. This examination is performed to demonstrate the caliber and patency of the ducts, the status of the sphincter of the hepatopancreatic ampulla, and the pres­ ence of residual or previously undetected stones or other pathologic conditions.

Postoperative cholangiography is per­ formed in the radiology department. Pre­ liminary preparation usual ly consists of the fol lowing: I . The drainage tube is clamped the day precedi ng the examination to let the tube fi l l with bile as a preventive mea­ sure against air bubbles entering the ducts, where they would simulate cho­ lesterol stones. 2. The preceding meal is withheld. 3. When indicated, a cleansing enema is ad­ ministered about I hour before the exam­ ination. Premedication is not required. The contrast agent used is one of the water-soluble organic contrast media. The density of the contrast medium used i n postoperative cholangiograms is recom­ mended to be no more than 25% to 30% because small stones may be ob cured with a higher concentration. After a preliminary radiograph of the abdomen has been obtained, the patient is adj usted in the RPO position (AP obl ique projection) with the right upper quadrant of the abdomen centered to the midli ne of the grid (Figs. 1 6-56 and 1 6-57).

Right hepatic duct Hepatic duct

Hube Common bile duct

Pancreatic duct Contrast medium in duodenum

Fig. 1 6-56 AP oblique postoperative cholangiogram, RPO position.

1 12

With universal precautions employed, the contrast medium is injected under flu­ oroscopic control, and spot and conven­ tional radiographs are made as i ndicated. Otherwise 24 X 30 cm IRs are exposed serially after each of several fractional i n­ jections of the medi um and then at speci­ fied intervals until mo t of the contrast so­ lution has entered the duodenum. Stern, Schein, and Jacobson I stressed the importance of obtaining a lateral pro­ jection to demonstrate the anatom ic branching of the hepatic ducts in this plane and to detect any abnormal ity not otherwise demonstrated ( Fig. 1 6-58). (See p. 86 for a description of lateral position­ ing.) The clamp generally is not removed from the T-tube before the exami nation is completed. Therefore the patient may be turned onto the right side for this study. 'Stern WZ, Schein CJ, Jacobson HG: The signifi­ cance of the lateral view in T -tube cholangiography, AJR 87:764. 1 962.

Fig. 1 6-57 AP oblique postoperative cholan­ giogram, RPO position, showing multiple stones in common bile duct (arrows).

Fig. 1 6-58 Right lateral cholangiogram showing anteroposterior location of T-tube (dots), common bile duct (arrow), and he­ patopancreatic ampulla (duct of Vater) (arrowhead).

1 13

PANCREAS

ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY Endoscopic retrograde cholangiopancre­ Qtography (ERep) is a procedure used to diagnose bil iary and pancreatic pathologic conditions. ERCP is a useful diagnostic method when the biliary ducts are not di­ lated and when no obstruction exists at the ampulla. ERCP is performed by passing a fiber­ optic endoscope through the mouth into the duodenum under fluoroscopic control. To ease passage of the endoscope, the pa­ tient's throat is sprayed with a local anes­ thetic. Because this causes temporary pha­ ryngeal paresis, food and drink are usually prohibited for at least I hour after the ex­ amination. Food may be withheld for up to 10 hours after the procedure to mi nimize irritation to the stomach and smal l bowel .

After the endoscopist locates the he­ patopancreatic ampu l l a ( ampu l l a of Yater), a small cannula is passed through the endoscope and directed i nto the am­ pulla ( Fig. 1 6-59). Once the cannula is properly placed, the contrast medium is i njected into the common bile duct. The patient may then be moved, fluoroscopy performed, and spot radiographs taken ( Figs. 1 6-60 and 1 6-6 1 ). Oblique spot ra­ diographs may be taken to prevent overlap of the common bile duct and the pancre­ atic duct. Because the injected contrast material should drain from normal ducts within approxi mately 5 minutes, radi­ ographs must be exposed immediately.

The contrast medium that is used de­ pends on the preference of the radiologist or gastroenterologist. Dense contrast agents opacify small duct very wel l , but they may obscure small stones. If small stones are suspected, use of a more dilute contrast medium is suggested. ' A history of patient sensitivity to an iodi nated con­ trast medium in another exami nation (e.g., intravenous urography) does not necessar­ i l y contraindicate its use for ERCP. However, the patient must be watched carefully for a reaction to the contrast medium during ERCP. ERCP is often indicated when both cli nical and radiographic findings indicate abnormalities in the biliary system or pan­ creas. OCG, ultrasound examination, or IYC is usually performed before ERCP. Ultrasonography of the upper part of the abdomen before endoscopy is often rec­ ommended to assure the physician that no pseudocysts are present. This step is i m­ portant because contrast medium i njected into pseudocysts may lead to inflamma­ tion or rupture of the pseudocysts. 'Cotton P,

William

C: Prac/ical gas/mimes/inal en­

doscopy. Oxford, England, 1 980, Blackwell .

. ----.-- -

-

Fig. 1 6-59 Cannulation procedure. Procedure is begun with patient in left lateral position. This schematic diagram gives an overview of the location of the examiner and the posi­ tion of the scope and its relationship to various internal organs. Inset: Magnified view of the tip of the scope with cannula in papilla. (From Stewart ET, Vennes JA. Gennen JE: Atfas of endoscopic retrograde cholangiopancreatography, St Louis, 1 977, Mosby.) 1 14

PANCREAS

Common hepatic duct Pancreatic duct Cystic stump

Common bile duct Endoscope

Fig. 1 6-60 ERCP spot radiograph, PA projection.

Pancreatic duct

Cannula Fig. 1 6-61 ERCP spot radiograph, PA projection.

1 15

SUM MARY OF PROJ ECTI ONS

PROJECTIONS,

POSITIONS,

& METHODS

RAO or LPO Lateral

R or L

PA Stomach and duodenum

PA axial

Stomach and duodenum

PA

Stomach and duodenum

AP

RAO

Stomach and duodenum 1 52

Stomach and duodenum

AP

1 54

Superior stomach and distal esopha us

PA obllque

RAO

1 56

Stomach and duodenum serial and mucosal studies

PA oblique

RAO

1 58

Small Intestine

PA or AP

1 74

PA

1 76

PA axial

Lar e Intestine

PA obllque

RAO

1 78

Lar e Intestine

PA oblique

LAO

Large Intestine

Lateral

R or L

Large Intestine

AP

Lar�e Intestine

AP axial

1 79 1 80

I �

g

1 77

1 81 1 82 1 83 1 85 1 86 1 87 1 88 1 89

1� ��

• • • • • •

WOLF

Lar�e Intestine

AP oblique

LPO

Lar�e Intestine

AP obllque

RPO

Large Intestine

AP or PA

R lateral decubitus

Large Intestine

PA or AP

L lateral decubitus

Large Intestine

Lateral

R or L ventral decubitus

Large Intestine

AP, PA, oblique, lateral

Upright

Large Intestine

Axial

CHASSARDLAPIN �

I

Icons in the Essential column indicate projections frequently performed in the United States and Canada. Students should be competent in these projections.

,,:�

ANATOMY

Digestive System

Esophagus

The digestive system consists of two parts: the accessory glands and the alimentGlY canal. The accessory glands, which in­ cl ude the salivary glands, liver, gallblad­ der, and pancreas, secrete digestive en­ zymes i nto the alimentary canal. (These glands are described in Chapter 1 6. ) The alimentary canal is a musculomembra­ nous tube that extends from the mouth to the anus. The regions of the ali mentary canal vary in diameter according to func­ tional requirements. The greater part of the canal, which is about 29 to 30 feet (8.6 to 8.9 m ) in length, l ies in the abdominal cavity. The component parts of the ali­ mentary canal ( Fig. 1 7- 1 ) are the mouth, in which food is masticated and converted into a bolus by insalivation; the pharynx and esophagus, which are the organs of swal lowi ng; the stomach, in which the di­ ge tive process begins; the small intestine, in which the digestive process is com­ pleted; and the large intestine, which is an organ of egestion and water absorption that terminates at the anus.

The esophagus is a long, muscular tube that carries food and saliva from the laryn­ gopharynx to the stomach (see Fig. 1 7- 1 ) . The adult esophagus is approximately 1 0 inches ( 24 cm) i n length and % i nch ( 1 .9 cm) in diameter. Simi lar to the rest of the alimentary canal, the esophagus has a wall composed of four layers. Beginning with the outermost layer and movi ng in, the layers are as follows: Fibrous layer M uscular layer Submucosal layer M ucosal layer • •

• •

The esophagus lies in the midsagittal plane. It originates at the level of the sixth cervical vertebra, or the upper margin of the thyroid cartilage. The esophagus enters the thorax from the superior portion of the neck. In the thorax the esophagus passes through the mediastinum, anterior to the vertebral bodies and posterior to the tra­ chea and heart (see Fig. 1 7- 1 , 8). I n the lower thorax the esophagus passes through the diaphragm at T 1 0. I nferior to the di­ aphragm the esophagus curves sharply left, increases in diameter, and joins the stomach at the esophagogastric junction, which is at the level of the xiphoid tip (T I I ). The expanded portion of the terrni­ nal esophagus, which lies in the abdomen, is called the cardiac antrum.

A B

Tongue

" - �i--,f- Parotid gland J .r rf!" 4,tr

_ _ -

Sublingual gland

Esophagus

Stomach

�����tJ:1'--- Pancreas

Aorta --t------""?-=-:::".;;:

IH-+-- Large intestine

Duodenum

-01---11- Heart

��;::(=+4J-.!l_- Small intestine

Vermiform ---+---=� appendix Rectum ---J'----_\_

��-t-- Diaphragm T l 2 ---t--f:=C

-tI'#-------+ Fundus

Fig. 1 7- 1 A, Alimentary canal and its accessory organs. with liver lifted to show gallblad­ der. B, Lateral view of the thorax. showing the esophagus positioned anterior to the verte­ bral bodies and posterior to the trachea and heart. 1 19

Stomach The stomach is the di lated, saclike portion of the digestive tract extending between the e ophagus and the small i ntestine ( Fig. 1 7-2). Its wall is composed of the same four layers as the esophagus. The stomach is divided i nto four parts: Cardia Fundus Body Pyloric portion • •

• •

The cardia of the stomach is the section immediately surrounding the esophageal opening. The fundus is the superior portion of the stomach that expands superiorly and fills the dome of the left hemjdiaphragm. When the patient is in the upright position, the fundus is usually fil led with gas and in radiography is referred to as the gas bubble. Descending from the fundus and beginning at the level of the cardiac notch is the body of the stomach. The inner mucosal layer of the body of the stomach contains numerous longitudinal folds called rugae. When the stomach is full, the rugae are smooth. The body of the stomach ends at a vertical plane passing through the angular notch. Distal to this plane is the pyloric portion of the stom­ ach, which consists of the pyloric an/rum and the narrow pyloric canal to the imme­ mate right of the angular notch.

The stomach has an anterior and a pos­ terior surface. The right border of the stomach is marked by the lesser curvature. The lesser curvature begins at the esopha­ gogastric junction, is continuous with the right border of the esophagus, and is a con­ cave curve ending at the pylorus. The left and inferior borders of the stomach are marked by the greater curvature. The greater curvature begins at the sharp angle at the esophagogastric junction, the car­ diac notch, and fol lows the superior curva­ ture of the fundus and then the convex cur­ vature of the body down to the pylorus. The greater curvature is four to five times longer than the lesser curvature.

Cardiac notch Cardiac sphincter

A

B

Cardiac antrum Cardia Pyloric portion I

Pyloric sphincter

'"

Rugae

Duodenum

Fig. 1 7-2 A, Anterior surface of stomach. B, Interior view. C, Axial CT image of the upper abdomen showing the position of the stomach in relation to surrounding organs. Note con­ trast media (white) and air (black) in the stomach.

c

1 20

The entrance to and the exit from the stomach are each controlled by a muscle sphi ncter. The esophagus joins the stom­ ach at the esophagogastric junction through an opening termed the cardiac orifice. The muscles controlling the car­ diac orifice are called the cardiac sphinc­ ter. The opening between the stomach and the small intestine is the pyloric orifice, and the muscles controlling the pyloric orifice are cal led the pyloric sphincter. The size, shape, and position of the stomach depend on body habitus and vary with posture and the amount of stomach contents ( Fig. 1 7-3). In persons of hyper­ sthenic habitus the stomach is al most hor­ izontal and is high, with its mo t depen­ dent portion well above the umbilicus. I n persons o f asthenic habitus the stomach is vertical and occupies a low position, with i ts most dependent portion extending wel l below the transpyloric, o r interspinous, line. Between these two extremes are the intermediate types of bodily habitus with corresponding variations in the shape and position of the stomach. Note that the habitus of 85% of the popu lation is either sthenic or hyposthenic. Radiographers should become fami l iar with the various positions of the stomach in the different types of body habitus so that accurate po­ sitioning of the stomach is ensured.

y Hypersthenic 5%

The stomach has several functions i n the digestive process. The stomach serves as a storage area for food until it can be further digested. It is also where food is broken down. Acids, enzymes, and other chemical s are secreted to chemically break down food. Food is also mechani­ cally broken down through churn i ng and peristalsis. Food that has been mechani­ cally and chemically altered in the stom­ ach is transported to the duodenum as a material cal led chyme.

y

y

Sthenic

Hyposthenic 35%

50%

y Asthenic 1 0%

Fig. 1 7-3 Size, shape, and position of the stomach and large intestine for the four different types of body habitus. Note the extreme difference between the hypersthenic and as­ thenic types.

121

Cystic duct Common hepatic duct Common bile duct

Gallbladder

A Hepatopancreatic ampulla

?jj;,>%�'r-'-_ Pancreatic duct

Major duodenal papilla (orifice of biliary and pancreatic ducts)

Pancreas

Duodenal bulb 1 st (superior) region

i-\f''---- Suspensory muscle of the duodenum

B

-1-- 4th (ascending) region

Intestinal wall

Duodenojejunoflexure

Villi

Jejunum

Fig. 1 7-4 A, Duodenal loop in relation to biliary and pancreatic ducts. B, Anatomic areas of the duodenum. Inset: Cross section of duodenum. showing villi. C, Loops of small intestine lying in central and lower abdominal cavity.

-=---f--�I#i�����----�

Loops of jejunum and ileum c

Ascending -H-r.�, colon Cecum ----+-����

1 22

Smoll i ntestine The small intestine extends from the py­ loric sphi ncter of the stomach to the ileo­ cecal valve, where it j oins the large intes­ tine at a right angle. Digestion and absorption of food occur in this portion of the alimentary canal . The length of the adult small intestine averages about 22 feet (6.5 m), and its diameter gradual ly di min­ i shes from approximately I � inches (3.8 cm) in the proximal part to approxi mately I inch (2.5 cm) in the distal part. The wall of the mall intestine contains the same four layers as the wal ls of the esophagus and stomach. The mucosa of the small in­ testine contains a series of fingerl ike pro­ jections called villi, which help facil itate the process of digestion and absorption. The small intestine is divided into three portions: Duodenum Jejunum I leum • • •

The duodenum is 8 to 1 0 inches (20 to 24 cm) in length and is the widest portion of the smal l intestine (Fig. l 7-4). It is retroperitoneal and relatively fixed in posi­ tion. Beginning at the pylorus, the duode­ num fol lows a C-shaped course. Its four re­ gions are described as the first (superior), second (descending), third (horizontal or inferior), and fourth (ascending) portions. The segment of the first portion is called the duodenal bulb because of its radio­ graphic appearance when it is fil led with an opaque contrast medi um. The second por­ tion is about 3 or 4 inches (7.6 to 1 0 em) long. This segment passes inferiorly along the head of the pancreas and in close rela­ tion to the undersurface of the liver. The common bile duct and the pancreatic duct usually unite to form the hepatopancreatic ampul/a, which opens on the summit of the greater duodenal papilla in the duodenum. The third pOltion passes toward the left at a sl ight superior inclination for a distance of about 2 � inches (6 cm) and continues as the fourth portion on the left side of the veltebrae. This portion joins the jejunum at a sharp curve called the duodenojejunal flexure and is supported by the suspensOl)l muscle of the duodenum ( ligament of Treitz). The duodenal loop, which lies in the econd pOltion, is the most fixed part of the small intestine and normally lies in the upper part of the umbi lical region of the ab­ domen; however, its position varies with body habitus and with the amount of gas­ tric and intestinal contents.

The remainder of the small intestine is arbitrari ly divided into two pOltions, with the upper two fifths referred to as the je­ junum and the lower three fifths as the ileum. The jejunum and ileum are gath­ ered into freely movable loops, or gyri, and are attached to the posterior wall of the abdomen by the mesentery. The loops lie in the central and lower part of the ab­ domi nal cavity within the arch of the large i ntestine.

1 23

large I ntestine The Large intestine begins i n the right iliac region, where it joins the i leum of the small i ntestine, forms an arch surrounding the loops of the small intestine, and ends at the anus ( Fig. 1 7-5) . The large i ntestine has four main parts: Cecum Colon Rectum Anal canal •

• • •

The large intestine is about 5 feet ( 1 .5 m) long and is greater in diameter than the small intestine. The wall of the large intes­ tine contains the same four layers as the walls of the esophagus, stomach, and small intestine. The muscular portion of the in­ testinal wall contains an external band of longitudinal muscle that forms into three thickened bands called taeniae coLi. One band is positioned anteriorly, and two are positioned posteriorly. These bands create a pulling muscle tone that forms a series of pouches called the haustra. The main func­ tions of the large intestine are reabsorption of fluids and elimination of waste products.

The cecum is the pouchlike portion of the large intestine and is below the junc­ tion of the i leum and the colon . The ce­ cum is approximately 2Y2 i nches (6 cm) i n length and 3 i nches ( 7 . 6 c m ) i n diameter. The vermiform appendix is attached to the posteromedial side of the cecum. The ap­ pendix is a narrow, wormlike tube that is about 3 i nches (7.6 cm) long. The iLeoce­ caL vaLve is just below the junction of the ascending colon and the cecum. The valve projects into the lumen of the cecum and guards the opening between the i leum and the cecum.

Left colic flexure

Right colic -­ flexure

Transverse colon

Descending colon

Ascending colon

Taenia coli

Ileocecal -+4f-l,,-t. valve

A

r--tt.....R-. ... �'+--- Sigmoid

B

Haustra

Cecum

Sigmoid colon

colon

.:..jj,.L-7""I�'P.'---r-+ Rectum '-"'-- Anus

Fig. 1 7-5 A, Anterior aspect of large intestine posi­ tioned in abdomen. B, Anterior aspect of large in­ testine. C, Axial CT of the upper abdomen showing an actual image of the transverse colon (TC) posi­ tioned in the anterior abdomen.

c

1 24

The colon is subdivided i nto ascending, transverse, descending, and sigmoid por­ tions. The ascending colon passes superi­ orly from its junction with the cecum to the undersurface of the liver, where i t joins the transverse portion a t a n angle cal led the right colic flexure (formerly he­ patic flexure ) . The transverse colon, which is the longest and most movable part of the colon, crosses the abdomen to the undersurface of the spleen. The trans­ verse portion then makes a sharp curve, called the left colic flexure (formerly splenic flexure), and ends in the descend­ i ng portion. The descending colon passes inferiorly and medially to its junction with the sigmoid portion at the superior aper­ ture of the lesser pelvis. The sigmoid colon curves to form an S-shaped loop and ends in the rectum at the level of the third sacral segment.

The rectum extends from the sigmoid colon to the anal canal. The anal canal terminates at the anus, which is the exter­ nal aperture of the large i ntestine ( Fig. 1 7-6). The rectum i s approximately 6 i nches ( 1 5 cm) long. The distal portion, about I i nch (2.5 cm) in length, is con­ stricted to form the anal canal . Just above the anal canal is a dilation call ed the rec­ tal ampulla. Fol lowing the sacrococ­ cygeal curve, the rectum passes inferiorly and posteriorly to the level of the pelvic floor and then bends sharply anteriorly and i nferiorly into the anal canal, which extends to the anus. The rectum and anal canal thus have two anteroposterior curves, a fact that must be remembered when an enema tube is i nserted.

The size, shape, and position of the l arge i ntestine vary greatly, depending on body habitus (see Fig. 1 7-3). I n hypersthenic pa­ tients the large intestine is positioned around the periphery of the abdomen and therefore may require more radiographs to demonstrate i ts entire length. At the other extreme is the asthenic patient's large in­ testine, which is bunched together and po­ sitioned low in the abdomen.

A Rectal ampulla

---

B

Anal canal

Anus

Fig. 1 7-6 A, Sagittal section showing direction of anal canal and rectum. B, Axial CT of the lower pelvis showing the rectum and sigmoid colon in relation to surrounding organs. (8, From Kelley L: Sectional anatomy, St Louis. 1 997. Mosby.)

1 25

EXPOSURE TEC H N IQUE C HART ESSE NTIAL PROJ ECTIONS D I G ESTIVE

SYST E M , A L I M E N TA RY

Part

cm

kVp'

mA

Esophagus*: AP & PA

16

1 10

300s

Obliques

21

1 10

Lateral

30

mAs

AEC

CANAL

SID

IR

Doset (mrad)

0.0

48 in.

35

x

43 cm

60

300s

0.0

48 in.

35

x

43 cm

75

1 10

300s

0.0

48 in.

35

x

43 cm

1 60

21

1 00

300s

•• •

48 in.

30

x

35 cm

329

PA Axial

24

1 00

300s

•• •

48 in.

35

x

43 cm

395

PA & AP Oblique

24

1 00

300s

•• •

48 in.

30

x

35 cm

460

Lateral

27

1 10

300s

•• •

48 in.

30

x

35 cm

597

Small Intestine*: PA & AP

21

1 00

300s

•• •

48 in.

35

x

43 cm

329

Large Intestine*: PA & AP

21

1 00

300s

•••

48 in.

35

x

43 cm

329

PA & AP Axial

24

1 00

300s

•• •

48 in .

35

x

43 cm

460

PA & AP Oblique

24

1 00

300s

•• •

48 in.

35

x

43 cm

460

Lower Lateral

31

1 20

300s

.:

48 in.

24

x

30 cm

853

AP & PA Decubitus

24

1 10

300s

•• •

48 in.

35

x

43 cm

362

Stomach and Duodenum*: PA & AP

s, Small focal spot. 'kVp values are for a 3-phase 1 2-pulse generator. 'Relative doses for comparison use. All doses are skin entrance for average adult at cm indicated. 'Bucky, 1 6: 1 Grid. Screen/Film Speed 300.

SUMMARY OF ANATOMY* Digestive system

Esophagus

Alimentary canal

mouth pharynx esophagus stomach small intestine large intestine (colon) anus

fibrous layer muscular layer submucosal layer mucosal layer esophagogastric junction cardiac antrum cardiac notch

Accessory glands

Stomach

salivary glands liver gallbladder pancreas

cardia fundus body rugae angular notch pyloric portion pyloric antrum pyloric canal lesser curvature cardiac notch greater curvature

cardiac orifice cardiac sphincter pyloric orifice pyloric sphincter chyme Small intestine

villi duodenum (4 regions) first (superior) duodenal bulb second (descending) major duodenal papilla third (horizontal) fourth (ascending) duodenojejunal flexure suspensory muscle of the duodenum jejunum ileum

Large intestine

taeniae coli haustra cecum vermiform appendix ileocecal valve colon ascending colon right colic flexure transverse colon left colic flexure descending colon sigmoid colon rectum rectal ampulla anal canal anus

'See Addendum at the end of the volume for a summary of the changes in the anatomic terms that were introduced in the 9th edition. 1 26

S U M MARY OF PATH OLOGY Condition

Definition

Achalasia

Failure of the smooth muscle of the alimentary canal to relax

Appendicitis

Inflammation of the appendix

Barrett's Esophagus

Peptic ulcer of the lower esophagus, often with stricture

Bezoar

Mass in the stomach formed by material that does not pass into the intestine

Carcinoma

Malignant new growth composed of epithelial cells

Colitis

Inflammation of the colon

Diverticulitis

Inflammation of diverticula in the alimentary canal

Diverticulosis

Diverticula in the colon without inflammation or symptoms

Diverticulum

Pouch created by the herniation of the mucous membrane through the muscular coat

Esophageal Varices

Enlarged tortuous veins of the lower esophagus

Gastritis

Inflammation of the lining of the stomach

Hiatal Hernia

Protrusion of the stomach through the esophageal hiatus of the diaphragm

Hirschsprung's or Congenital Aganglionic Megacolon

Absence of parasympathetic ganglia, usually in the distal colon, resulting in the ab­ sence of peristalsis

Ileus

Failure of bowel peristalsis

Inguinal Hernia

Protrusion of the bowel into the groin

Intussusception

Prolapse of a portion of the bowel into the lumen of an adjacent part

Malabsorption Syndrome

Disorder where subnormal absorption of dietary constituents occurs

Celiac Disease or Sprue

Malabsorption disease caused by a mucosal defect in the jejunum

Meckel's Diverticulum

Diverticulum of the distal ileum, similar to the appendix

Polyp

Growth or mass protruding from a mucous membrane

PyloriC Stenosis

Narrowing of the pyloric canal causing obstruction

Reflux

Backward flow of the stomach contents into the esophagus

Regional Enteritis or Crohn's

I nflammation of the terminal portion of the ileum

Ulcer

Depressed lesion on the surface of the alimentary canal

Ulcerative Colitis

Recurrent disorder causing inflammatory ulceration in the colon

Volvulus

Twisting of a bowel loop upon itself

Zenker'S Diverticulum

Diverticulum located just above the cardiac portion of the stomach

1 27

,.�

RAD I OGRAPHY

Technical Considerations GASTROI NTESTI NAL TRANSIT Peristalsis is the term applied to the con­ traction waves by which the digestive tube propels its contents toward the rectum. Normally three or four waves per minute occur in the fi l led stomach. The waves be­ gin in the upper part of the organ and travel toward the pylorus. The average emptying time of the normal stomach is 2 to 3 hours. Peristaltic action in the intestines is greatest i n the upper part of the canal and gradually decreases toward the lower por­ tion. In addition to peristaltic waves, lo­ calized contractions occur i n the duode­ num and the jejunum. These contractions usually occur at i ntervals of 3 to 4 seconds during digestion. The first part of a "bar­ ium meal" normally reaches the i leocecal valve in 2 to 3 hours and the last portion in 4 to 5 hours. The barium usual ly reaches the rectum within 24 hours.

1 28

,�

The specialized procedures commonly used in radiologic examinations of the esophagus, stomach, and i ntestines are discussed i n this section. The esophagus extends between the pharynx and the car­ diac end of the stomach and occupies a constant position in the posterior part of the mediastinum, where its radiographic demonstration presents l ittle difficu lty when a contrast medium is used. On the other hand, the stomach and intestines vary in size, shape, position, and muscular tonus according to the body habitus (see Fig. 1 7-3). In addition to the normal struc­ tural and functional differences, an exten­ sive variety of gastrointestinal abnormali­ ties can cause further changes i n location and motil ity. These variations make the i nvestigation of every gastrointestinal pa­ tient an i ndividual study, and meticulous attention must be given to each detail i n the examination procedure.

EXAMINATION PROCEDURE The alimentary canal is usually examined using a combination of fluoroscopy and radiography. Fluoroscopy makes it possi­ ble to observe the canal in motion, per­ form special mucosal studies, and deter­ mine the subsequent procedure required for a complete examination. I mages are obtained, as i ndicated, during and after the fluoroscopic examination to provide a permanent record of the fi ndings. Contrast media

Because the thin-walled alimentary canal does not have sufficient density to be demonstrated through the surrounding structures, its radiographic demonstration requires the use of an artificial contrast medium. Barium sulfate, which is a water­ i nsoluble salt of the metallic element bar­ ium, is the contrast medium universally used i n examinations of the alimentary canal ( Fig. 1 7-7). The barium sulfate used for this purpose is a specially prepared, chemically pure product to which various chemical substances have been added. B arium sulfate is available as either a dry powder or a l iquid. The powdered barium has different concentrations and is mixed with plain water. The concentration de­ pends on the part to be examined and the preference of the physician.

A number of special barium sulfate prod­ ucts are also avai lable. Those with finely di­ vided barium sulfate particles tend to resist precipitation and to remain in suspension longer than the regular barium preparations. Some barium preparations contain gums or other suspending or dispersing agents and are referred to as suspended orfiocculation­ resistant preparations. The speed with which the bari um mix­ ture passes through the alimentary canal depends on the suspending medium, the temperature of the medium, and the consistency of the preparation, as well as the motile function of the ali mentary canal. In addition to barium sulfate, watersolubLe, iodinated contrast media suitable for opacification of the ali mentary canal are avai lable ( Fig. 1 7-8). These preparations are modifications of basic intravenous urographic media such as diatrizoate sodium and diatrizoate meglumine.

Stomach

Pyloric portion Duodenum

Small bowel loops

Fig. 1 7-7 Barium sulfate suspension in stomach. sthenic body habitus.

Fig. 1 7-8 Water-soluble. iodinated solution in the stomach.

1 29

Left colic flexure

Right colic flexure Transverse colon

Descending colon Ascending colon

Cecum

Sigmoid colon

Rectum

Fig. 1 7-9 Barium sulfate suspension administered by rectum, sthenic body habitus,

Fig. 1 7- 1 0 Water-soluble, iodinated solution administered by mouth,

1 30

Iodinated solutions move through the gastrointestinal tract more quickly than barium sulfate suspensions (Figs. l 7-9 and 1 7- 1 0) . An iodinated sol ution nor­ mally clears the stomach in 1 to 2 hours, and the entire iodinated contrast column reaches and outl ines the colon in about 4 hours. An orall y administered iodinated medium differs from barium sulfate in the following ways: 1 . It outlines the esophagus, but it does not adhere to the mucosa as well as a barium sulfate suspension does. 2. It affords an entirely satisfactory exam­ ination of the stomach and duodenum, including mucosal del i neation. 3 . It permits rapid survey of the entire small i ntestine but fails to provide clear anatomic detail of this portion of the alimentary canal. This failure results from the d i l ution of the contrast medium and the resultant decrease i n opacification. 4. Because of the normal rapid absorption of water through the colonic mucosa, the medium again becomes densely concentrated in the large i ntestine. Consequently, the entire large inte tine is almost as wel l as del ineated with ret­ rograde fi l li ng using a barium sulfate suspension . As a result of its increased concentration and accelerated transit time, a reasonably rapid investigation of the large intestine can be performed by the oral route when a patient cannot co­ operate for a satisfactory enema study. A great advantage of water-soluble media is that they are easily removed by as­ piration either before or during surgery. Furthermore, if a water-soluble, iodinated medium escapes i nto the peritoneum through a preexisting perforation of the stomach or i ntestine, no ill effects result. The medium is readily absorbed from the peritoneal cavity and excreted by the kid­ neys. This is a definite advantage when perforated ulcers are under investigation. A disadvantage of iodinated prepara­ tions is their strongly bitter taste, which can be masked only to a limited extent. Patients should be forewarned so that they can more easily tolerate i ngesting these agents.

Radiologic apparatus

Fluoroscopic equipment used today con­ tains highly sophisticated image intensifi­ cation systems ( Fig. 1 7- 1 1 ). These systems can be connected to accessory units such as cine fi lm recorders, television systems, spot-film cameras, digital-image cameras, and video recorders. Remote-control fluoro copic rooms are also available and are used by the fluoroscopist located in an adjacent control area (Fig. 1 7- 1 2). Although conventional I R-Ioaded spot­ i mage devices are sti l l used with image intensification i n the majority of fluoro­ scopic i nstallations, developments i n spot-image cameras have resulted i n a n i ncrease i n the number o f spot-i mage cameras and a slight decline in the num­ ber of conventional I R-Ioaded spot-film units. Current spot-image cameras expose the patient to less radiation and require less time to expose the spot image during the fluoroscopic exami nation. The re­ duced radiation to the patient also results in less heat load on the x-ray tube than oc­ curs with conventional spot i magi ng. The most common spot-image cameras use film widths of 1 00 and 1 05 mm. Modern fluoroscopic systems now produce the spot- image images on l aser pri nters. Digital fluoroscopic units, which permit the recording of multiple fluoroscopic im­ ages on one laser film (see Chapter 35 ), are also avai lable.

Compression and palpation of the ab­ domen are often performed during an ex­ ami nation of the alimentary canal. M any types of compression devices are avai l­ able. The fluoroscopic unit pictured i n Fig. 1 7- 1 1 shows a compression cone in contact with the patient's abdomen. Thi device i s often used during general fluoroscopic exami nations.

Other types of commercial compres­ sion devices include the pneumatic com­ pression paddle shown in Fig. 1 7- 1 3 . This device is often placed under the duodenal bu lb and then inflated to place pressure on the abdomen. The air is then slowly re­ lea ed, and the compression on the body part is elimi nated.

Fig. 1 7- 1 1 Image intensification system, with compression cone in contact with abdomen.

Fig. 1 7 - 1 2 Remote-control fluoroscopic room, showing patient flu­ oroscopic table (left) and fluoroscopist's control console (right). The fluoroscopist views the patient through the large window.

Fig. 1 7- 1 3 Compression paddle: inflated (above) and non in­ flated (below).

1 31

Preparation of examining room

Exposure time

The exami ning room should be com­ pletely prepared before the patient enters. In preparing the room, the radiographer should observe the fol lowi ng steps: Adjust the equipment controls to the appropriate settings. Have the footboard and shoulder sup­ port available. Check the mechanism of the spot-film device and/or spot-film camera, and see that sufficient fi lms are available. Prepare the required type and amount of contrast medium. Before beginning the examination, the radiographer should do the fol lowi ng: Explain to the patient that the barium sulfate mixture may taste a little chalky. Inform the patient that the room may be somewhat darkened during fluoro copy. When the fluoroscopist enters the ex­ amining room, i ntroduce the patient and the fluoroscopist to each other.

One of the most i mportant considerations in gastrointestinal radiography is the elim­ i nation of motion. The highest degree of motor activity is normally found in the stomach and proxi mal part of the small in­ testine. The activity gradual ly decreases along the i ntestinal tract until it becomes fairly s low in the distal part of the large bowel. Peristaltic speed also depends on the i ndividual patient 's body habitus and is influenced by pathologic changes, body position, and respiration. The amount of exposure time for each region must be based on these factors. In esophageal examinations the radiog­ rapher should observe the fol lowing guidelines: Use an exposure time of 0. 1 second or less for upright radiographs. The time may be slightly longer for recumbent images because the barium descends more slowly when patients are in re­ cumbent positions.

•

•

•

•

•

•

•

•

Remember that barium passes through the esophagus fairly slowly if it is swal­ lowed at the end of ful l i nspiration. The rate of passage is i ncreased if the bar­ ium is wallowed at the end of moder­ ate i nspiration. However, the barium is delayed in the lower part for several seconds if it is swal lowed at the end of full expiration. Keep in mind that respiration is i nhib­ ited for several seconds after the begin­ n ing of degl utition, which allows suffi­ cient time for the exposure to be made without i nstructing the patient to hold his or her breath after swal lowi ng. I n examinations of the stomach and small i ntestine, the radiographer should observe the following guidel i nes: Use an exposure time of no longer than 0.2 second for patients with normal peristaltic activity and never more than 0.5 second; the exposure time should be 0. 1 second or less for those with hyper­ motility. Make exposures of the stomach and in­ testines at the end of expiration i n the routine procedure.

•

•

•

•

Fig. 1 7- 1 4 AP spot radiograph of barium-filled fundus of stomach.

1 32

Radiation Protection

Esophagus

During fluoroscopy, spot fi l m i ng ( Figs. 1 7 - 1 4 and 1 7- 1 5 ) , and radiographic fi lm­ i ng for either a partial or a complete gas­ troi ntestinal examination, the patient w i l l receive radiation. I t is taken for granted that properly added fi ltration is in place at all times in every x-ray tube in the ra­ diology department. I t is further assumed that based on the capacity of the ma­ chi nes and the best avai lable accessory equi pment, the exposure factors are ad­ justed to del iver the least possible radia­ t ion to the patient. Protection of the patient from unneces­ sary radiation is a professional responsi­ bil i ty of the radiographer. (See Chapter I of this atlas for specific guidelines.) In this chapter, the Shield gonads statement at the end of the Position of part section in­ dicates that the patient is to be protected from unnecessary radiation by restricting the radiation beam using proper col lima­ tion. It is also appropriate to place lead shielding between the gonads and the ra­ diation source when the clinical objectives of the examination are not compromised.

CONTRAST STUDIES The esophagus may be exami ned by per­ forming a full-column, sil1gle-contrast study in which only bari um or another ra­ diopaque contrast agent is used to fi l l the esophageal lumen. A double-contrast pro­ cedure also may be used. For this study, barium and carbon dioxide crystals (which liberate carbon dioxide) are the two con­ trast agents. No preliminary preparation of the patient is necessary. Barium sulfate mixture

A 30% to 50% weight/volume suspension I is useful for the fu l l-col umn, single­ contrast technique. A low-viscosity, high­ density barium developed for double­ contrast gastric examinations may be used for a double-contrast examination. What­ ever the weight/volume concentration of the barium, the most important criterion is that the barium flows sufficiently to coat the walls of the esophagus. The barium manufacturer's mixing instructions must be closely followed to attain optimum per­ formance of the contrast medium. ' Scukas J: Cont rast media. I n Margulis AR, Burhenne HJ, ed: A l imentary tract radiology, vol I , ed 4 , St Louis, 1 989, Mosby.

Fig. 1 7 - 1 5 Spot radiograph of air-contrast colon. showing left colic flexure.

1 33

Examination procedures

For a single-contrast examination ( Figs. 1 7- 1 6 to 1 7- 1 8), the fol lowi ng steps are observed: Start the fluoroscopic and spot-film ex­ aminations with the patient in the up­ right position whenever possible. Use the horizontal and Trendelenburg positions as i ndicated. After the fluoroscopic examination of the heart and lungs and when the pa­ tient is upright, instruct the patient to take the cup containing the barium sus­ pension in the left hand and to dri nk it on request. •

•

The radiologist asks the patient to swal­ low several mouthfuls of the bari um so that the act of deglutition can be observed to determine whether any abnormality is present. The radiologist instructs the pa­ tient to perform various breathing maneu­ vers under fluoroscopic observation so that spot radjographs of areas or lesions not otherwise demonstrated can be obtained.

•

Esophagus

Esophagus

Stomach -------�

Fig. 1 7- 1 6 AP esophagus, single-contrast study.

1 34

Thoracic vertebra ===�-

Fig. 1 7 - 1 7 Lateral esophagus, single­ contrast study.

The performance of the double-contrast esophageal examination (Fig. 1 7- 1 9 ) i s imilar t o that o f a single-contrast exami­ nation. For a double-contrast examination, a free-flowing, high-density barium must be used. A gas-producing substance, usu­ ally carbon dioxide crystals, can be added to the bari um mi xture or can be given by mouth immediately before the bari um sus­ pension is i ngested. Spot radiographs are taken during the examination, and delayed i mages may be obtained on request.

OPAQUE FOREIGN BODI ES Opaque foreign bodies lodged in the phar­ ynx or in the upper part of the esophagus can usually be demonstrated without the use of a contrast medium. A soft tissue neck or lateral projection of the retroster­ nal area may be taken for this purpose. The following steps are observed: Obtain a lateral neck radiograph at the height of swallowing for the deli neation of opaque foreign bodies in the upper end of the intrathoracic esophagus. Have the patient swal low. This elevates the i ntrathoracic esophagus a distance of two cervical segments, placing it above the level of the clavicles. Tufts or pledgets of cotton saturated with a thin barium suspension are some­ ti mes used to demonstrate an obstruction or to detect nonopaque foreign bodies in the pharynx and upper esophagus. •

•

Fig. 1 7 18 PA oblique esophagus, RAO po­ sition, single-contrast study. -

Fig. 1 7 - 19 PA oblique distal esophagus, RAO position, double-contrast spot image.

1 35

Esophagus

.. Ap, PA, OBLIQUE, AN D LATE RAL PROJECTIONS

., AP OR PA PROJECTION

�

•

35 x 43 cm lengthwise and centered so the top of the IR is positioned at the level of the mouth for i nclusion of the entire esophagus Image receptor:

Position of patient •

•

Position the patient a for che t radi­ ographs (AP, PA, oblique, and lateral; see Chapter 1 0). Because the RAO po­ sition of 35 to 40 degrees ( Fig. 1 7-20) makes it possible to obtain a wider space for an unobstructed i mage of the esophagus between the vertebrae and the heart, it is usual ly used in prefer­ ence to the LAO position. The LPO po­ sition has also been recommended. 1 Unless the upright position is specified ( Fig. 1 7-2 1 ), place the patient in the re­ cumbent position for esophageal studies (Figs. 1 7-22 and 1 7-23). The recumbent position is used to obtain more complete contrast filling of the esophagus (espe­ cially filling of the proximal part) by having the barium column flow against gravity. The recumbent position is rou­ tinely used for the demonstration of variceal distentions of the esophageal veins because varices ( Fig. 1 7-24) are be t fi l led by having the blood flow against gravity. Variceal filling is more complete during i ncreased venous pres­ sure, which may be applied by ful l expi­ ration or by the Valsalva maneuver (see Chapter 1 5 , page 59).

• •

•

The fol lowi ng steps are observed: Place the patient in the supine or prone position with the arms at the side and the shoulders and hips equidistant from the table. Center the midsagittal plane to the grid. Turn the head slightly, if needed, to fa­ cilitate drinking of the barium mixture. Shield gonads.

., LATERAL PROJECTION R or L position

The procedure is as fol lows: Place the patient in the lateral position faci ng the radiographer. Place the patient's arms forward. Center the midcoronal plane to the grid. Shield gonads.

•

• • •

Central ray

Perpendicular to the midpoint of the I R (the central ray will b e a t the level of T5-T6)

•

., AP OR PA OBLIQUE RAO or LPO position •

•

•

•

The steps are as fol lows: Position the patient in the RAO or LPO position with the midsagittal plane formi ng an angle of 35 to 40 degrees from the grid device. Adjust the patient's arms in a comfort­ able position with the shoulders lying in the same plane. Center the elevated side to the grid through a plane approxi mately 2 i nches (5 cm) lateral to the midsagittal plane (see Figs. 1 7-22 and 1 7-23). Shield gonads.

Structures shown

The contrast- medium-fi l led esophagus should be demonstrated from the lower part of the neck to the esophagogastric junction, where the esophagus joins the stomach. EVALUATION CRITERIA

The following should be clearly demon­ strated: General • • •

Esophagus from the lower part of the neck to its entrance into the stomach Esophagus fi lled with barium Penetration of the barium AP or PA projection

• •

Esophagus through the superimposed thoracic vertebrae No rotation of the patient

'Cockeri l l EM et al : Optimal visualization of esophageal varices, Am J Roellfgello/ 1 26:5 1 2, 1 976.

Fig. 1 7-20 PA oblique esophagus. RAO position. 1 36

Fig. 1 7-21 Upright PA oblique esophagus. RAO position.

Esophagus

Oblique projection •

•

Esophagus between the vertebrae and the heart lateral projection

• •

Patient's arm not interfering with visu­ alization of the proximal esophagus Ribs posterior to the vertebrae superim­ posed to show that the patient was not rotated •

NOTE: The general criteria apply to all projec­ tions: AP or PA, oblique, and lateral. Barium administration and respiration •

•

Feed the barium sulfate suspension to the patient by spoon, by cup, or through a drinking straw, depending on its con­ sistency. Ask the patient to swallow several mouthfuls of barium in rapid succes­ sion and then to hold a mouthful unti l immediately before the exposure.

Fig. 1 7-23 PA oblique proximal esophagus, RAO position, double-contrast spot film.

For the demonstration of esophageal varices, instruct the patient ( I ) to fully expirate and then to swallow the barium bolus and avoid i nspiration until the ex­ posure has been made or (2) to take a deep breath and, while holding the breath, to swallow the bolus and then perform the Valsalva maneuver (see Fig. 1 7-24). For other conditions, instruct the pa­ tient simply to swallow the barium bo­ l us, which is normally done during moderate i nspiration. Because respira­ tion is inhibited for about 2 seconds af­ ter swallowing, the patient does not have to hold his or her breath for the ex­ posure. If the contrast medium is swal­ lowed at the end of fu ll inspiration, make two or three exposures in rapid succession before the contrast medium passes i nto the stomach. For demon­ stration of the entire esophagus, it is sometimes necessary to make the expo­ sure while the patient is drinking the barium suspen ion through a straw 111 rapid and continuous swallows.

Fig. 1 7-22 PA oblique esophagus, RAO po­ sition. single-contrast study showing tear in esophageal lumen (arrow) and lesion par­ tially obstructing esophagus (arrowheads).

Fig. 1 7-24 Spot-film studies showing esophageal varices. 1 37

Stomach: Gastroi ntestinal Series Upper gastrointestinal tract radiographs are used to evaluate the distal esophagus, tomach, and some or all of the small in­ testine. An upper gastrointestinal exami­ nation ( Fig. 1 7-25 ), usually called a gas­ trointestinal or an upper gastrointestinal ( UG I ) series, may incl ude the fol lowing: I . A prelimi nary radiograph of the ab­ domen to delineate the liver, pleen, kidneys, psoas muscles, and bony structures and to detect any abdomi nal or pel v i c calcifications or tumor masses. The detection of calcifications and tumor mas es requires that the sur­ vey radiograph of the abdomen be taken after prelimi nary cleansing of the i ntestinal tract but before administra­ tion of the contrast medium. 2. An examination consisting of fluoro­ scopic and serial radiographic studies of the esophagus, stomach, and duode­ num using an ingested opaque mixture, usual ly barium sulfate. 3. W he n requested, a small i ntestine study consisting of radiographs ob­ tained at frequent i ntervals during pas­ sage of the contrast column through the smal l i ntestine, at which time the vermiform appendix and the i leocecal region may be exami ned.

Ambulatory outpatients or acutely ill patients, such as those with a bleeding ul­ cer, are usually exami ned in the supine poition using a fluoroscopic and spot-film procedure. Everything possible should be done to expedite the procedure. Any con­ trast preparation must be ready, and the ex­ ami nation room must be fully prepared be­ fore the patient is brought i nto the radiology department.

PRELIMINARY PREPARATION Preparation of patient

Because a gastrointestinal series is time­ consuming, the patient should be told the approxi mate time required for the proce­ dure before being assigned an appoint­ ment for an examination. The patient also needs to understand the reason for prelim­ i nary preparation so that ful l cooperation can be given. The stomach must be empty for an ex­ amination of the upper gastroi ntestinal tract (the stomach and small i ntestine). It is also desirable to have the colon free of gas and fecal material . When the patient i consti pated, a non-gas-forming laxative may be admini stered I day before the examination.

Fig. 1 7-25 Barium-filled AP stomach and small bowel. 1 38

Preparation usually consists of a soft, low-residue diet for 2 days to prevent gas formation from excessive fermentation of the i ntestinal contents. Cleansing enemas may be given to ensure a properly pre­ pared colon. An empty stomach is en ured by withholding both food and water after midnight for a period of 8 to 9 hours be­ fore the examination. When a small intes­ tine study is to be made, food and fluid are withheld after the evening meal. Because it is believed that nicotine and chewing gum stimulate gastric secretion and salivation, some physicians tel l pa­ tients not to smoke or chew gum after midnight on the night before the examina­ tion. This restriction is made to prevent excessive fluid from accumulating in the stomach and dil uting the barium suspen­ sion enough to interfere with its coating property. Barium sulfate suspension

The contrast medium general ly used i n routine gastrointestinal examinations is bari um sulfate mixed with water. The preparation must be thoroughly mjxed ac­ cording to the manufacturer's i nstruc­ tions. Specially formulated, high-density barium is also avai lable. Advances in the production of barium have all but elimj­ nated the use of a single barium formula for most gastroi ntesti nal exami nations performed i n the radiology department. Most physicians use one of the many commercially prepared barium suspen­ sions. These products are available in sev­ eral flavors, and some are conveniently packaged i n individual cup containing the dry ingredients. To these products, the ra­ diographer merely has to add water, recap the cup, and shake it to obtain a smooth suspension. Other barium suspensions are completely mixed and ready to use.

Contrast Studies Two general procedures are routinely used to examine the stomach: the single-contrast method and the double-contrast method. A biphasic examination is a combination of the si ngle-contrast and double-contrast methods on the same day. Hypotonic duo­ denography is another les commonly used examination.

SINGLE-CONTRAST EXAM I N ATION In the single-contrast method ( Fig. 1 7-26), a barium sulfate suspension is admi nis­ tered during the initial fluoroscopic exam­ ination. The barium suspension used for this study is usually in the 30% to 50% weight/vol ume range . ' The fol lowi ng steps are observed : Whenever possible, begin the exami na­ tion with the patient in the upright po­ sition. The radiologist may first examine the heart and lungs fluoroscopically and observe the abdomen to determ i ne whether food or fluid is in the stomach. Give the patient a glass of barium and instruct the patient to dri nk it as re­ quested by the radiologist. I f the patient is in the recumbent position, administer the suspension through a dri nking straw. The radiologist asks the patient to swal­ low two or three mouthfuls of the bar­ ium. During this time, examine and ex­ pose any i ndicated spot fi lms of the esophagus. By manual mani pulation of the stomach through the abdominal wall , the radiologist then coats the gas­ tric mucosa. Obtain i mages with the spot-film de­ vice or another compression device to demonstrate a mucosal lesion of the stomach or duodenum. After studying the rugae and as the pa­ tient dri nks the remainder of the barium suspension, observe the fi l l i ng of the stomach and further examine the duo­ denum. Based on this exami nation, the fol lowing can be accompl ished: I . Determine the size, shape, and posi­ tion of the stomach. 2. Examine the changing contour of the stomach duri ng peri stalsis. 3 . Observe the fi l ling and emptying of the duodenal bulb. •

•

4. Detect any abnormal alteration in the function or contour of the esoph­ agus, stomach, and duodenum. 5. Take spot fi lms as indicated. The contrast medi um normally begins to pass i nto the duodenum al most imme­ diately. However, nervous tension of the patient may delay transit of the contrast material . Fluoroscopy is performed with the pa­ tient in the upright and recumbent positions while the body is rotated and the table is angled so that all aspects of the esophagus, stomach, and duodenum are demon­ strated. Spot films are exposed as i ndi­ cated. I f esophageal i nvolvement is sus­ pected, a study is usually made with a thick barium suspension. Subsequent radiographs of the stomach and duodenum should be obtained i mme­ diately after fluoroscopy before any con­ siderable amount of the barium suspen­ sion passes into the jejunum.

Position of patient

The stomach and duodenum may be ex­ amined using PA, AP, oblique, and lateral projections with the patient in the upright and recumbent positions, as indicated by the fl uoroscopic findings. One variation of the supine posi tions is the LPO position. I n another variation, the head end of the table is lowered 25 to 30 degrees for the demonstration of a hiatal hernia. Final ly, for the demonstration of esophageal regurgitation and hiatal her­ nias, the head end of the table is lowered 1 0 to 1 5 degrees and the patient is rotated sl ightly toward the right side to place the esophagogastric (gastroesophageal) junc­ tion in profi le to the right of the spine. The medical significance of diagnosing hiatal hernias is a topic that has received much attention in recent years. Some authors re­ port little correlation between the pres­ ence of a hiatal hernia and gastrointestinal symptoms. If little correlation exi sts, ra­ diographic evaluation is of l ittle value in the majority of hiatal hern ias.

•

•

•

•

' S kucas J: Contrast media. I n Margulis AR. Burhenne HJ. editors: A limelltary tract radiolog.\'. vo l I . ed 4. St Louis. 1 989. Mosby.

Fig. 1 7-26 Barium-filled PA stomach, Single-contrast study. 1 39

DOUBLE -CONTRAST EXAMI NATION A second approach to the examination of the gastrointestinal tract is the double-contrast technique ( Fig. 1 7-27). The principal advan­ tages of this method over the single-contrast method are that small lesions are less easily obscured and the mucosal lining of the stomach can be more clearly visualized. However, for successful results, the patient must be able to move with relative ease throughout the examination. For double-contrast studies, the follow­ i ng steps are observed: To begin the examination, place the pa­ tient on the fluoroscopic table in the up­ right position. Give the patient a gas-producing sub­ stance in the form of a powder, crystals, pills, or a carbonated beverage. (An older technique involved placing pin­ holes in the sides of a drinking straw so that the patient ingested air while dri nk­ ing the barium suspension during the examination. ) Give the patient a small amount of commercial l y avai lable high-density barium suspension. For even coating of the stomach wal ls, the barium must flow freely and have a low viscosity. Many high-density barium products are available; these suspensions have weight/volume ratios of up to 250%. Place the patient i n the recumbent posi­ tion, and i nstruct him or her to turn from side to side or to roll over a few times. This movement serves to coat the mucosal lining of the stomach as the carbon dioxide continues to expand. The patient may feel the need to belch but should refrain from doing so until the examination is finished to ensure that an optimum amount of contrast material (gas) remains for the duration of the examination.

•

Just before the examination the patient may be given gl ucagon or other anti­ cholinergic medications intravenously or i ntramuscularly to relax the gastroin­ testinal tract. These medications im­ prove visualization by inducing greater distention of the stomach and intestines. Before administering these agents, the radiologist must consider a number of factors, includi ng side effects, con­ traindications, availabil ity, and cost.

Radiographic imaging procedure

The conventional i mages obtained after the fluoroscopic examination may be the same as those obtained for the single-contrast examination. Often the radiographs with the greatest amount of diagnostic informa­ tion are the spot images taken during fluo­ roscopy. Therefore the radiologist will, in most cases, have already obtained most of the necessary diagnostic radiographs. Nonfl uoroscopic i mages may not be needed.

•

•

Barium in fundus

-------:---:--::-

•

Air-filled, barium-coated stomach

•

Fig. 1 7-27 Double-contrast stomach spot images.

1 40

BI PHASIC EXAMI NATION The biphasic gastrointesti nal exami na­ tion i ncorporates the advantages of both the single-contrast and double-contrast upper gastroi ntestinal exami nations, with both examinations performed on the same day. The patient first undergoes a double­ contrast examination of the upper gas­ troi ntestinal tract. When this study is completed, the patient i s given an approx­ i mately 1 5% weight/volume barium sus­ pension and a s i ngle-contrast exami na­ tion is performed. This bi phasic approach i ncreases the accuracy of diagnosis w ith­ out signi ficantly i ncreasi ng the cost of the examination.

HYPOTONIC DUODE NOGRAPHY The use of hypotonic duodenography as a primary diagnostic tool has decreased in recent years. When lesions beyond the duo­ denum are suspected, the double-contrast gastrointestinal examination described can aid in the diagnosis. When pancreatic dis­ ease is suspected, computed tomography or needle biopsy can also be used. Thus hypotonic duodenography is needed less frequently.

First described by Liotta, I hypotonic duodenography requires i ntubation ( Figs. 1 7-28 and 1 7-29) and i s used for the eval­ uation of postbulbar duodenal lesions and the detection of pancreatic disease. A newer tubeless technique requires tempo­ rary drug-induced duodenal paralysis so that a double-contrast examination can be performed without interference from peri­ staltic activity. During the atonic state when the duodenum is distended with the contrast medium to two or three ti mes its normal size, it presses agai nst and outlines any abnormal ity i n the contour of the head of the pancreas. 'Liotta D: Puor Ie diagnostic des lumeus du pan­ creas: la duodenographic hypotonique, Lyoll Chir 50:445. 1 955.

Fig. 1 7-28 Hypotonic duodenogram showing deformity of duo­ denal diverticulum by small carcinoma of head of pancreas (arrow).

Fig. 1 7-29 Hypotonic duodenogram showing multiple defects (arrows) in duodenal bulb and proximal duodenum, caused by hypertrophy of Brunner's glands.

1 41

Stomach and Duodenum

'" PA PROJECTION Image receptor:

30 x

In adjusting thin patients in the prone position, support the weight of the body on pil lows or other suitable pads po i­ tioned under the thorax and pelvis. This adjustment keeps the stomach or duode­ num from pressing agai nst the vertebrae, with resultant pressure-fi ll ing defects.

35 cm

lengthwise. Position of patient •

For radiographic studies of the stomach and duodenum, place the patient in the recumbent position. However, the up­ right position is sometimes used to demonstrate the relative position of the stomach.

•

Position of part •

Adjust the patient's position, either re­ cumbent or upright, so that the midl i ne of the grid coincides with a sagittal plane passing halfway between the ver­ tebral column and the left lateral border of the abdomen. ( Fig. 1 7-30).

•

• •

Center the IR about 1 -2 inches above the lower rib margin at the level of L l ­ L2 when the patient is prone. ( Figs. 1 7-3 1 and 1 7-32). For upright i mages, center the IR 3 to 6 inches (7.6 to 1 5 cm) lower than L I -L2. The greatest visceral movement be­ tween the prone and the upright posi­ tions occurs in asthenic patients. Do not apply an immobilization band for standard radiographic projections of the stomach and i ntestines because the pressure is likely to cause fil l i ng defects and because it i nterferes with emptying and fil l i ng of the duodenal bulb, factors that are important in serial studies. Shield gonads. Respiration: Suspend at the end of ex­ piration unless otherwise requested.

Central ray •

Perpendicular to the center of the I R.

Structures shown

A PA projection of the contour of the bar­ ium-filled stomach and duodenal bulb is demonstrated . The upright projection shows the size, shape, and relative posi­ tion of the fil led stomach, but it does not give an adequate demonstration of the un­ fi l led fundic portion of the organ. In the prone position, the stomach moves superi­ orly I Y2 to 4 i nches ( 3 . 8 to 1 0 cm) accord­ ing to the patient's body habitus (Figs. 1 7-33 to 1 7-36). At the same time the stomach spreads horizontally, with a com­ parable decrease in its length. (Note that the fundus usually fills in asthenic patients.) Fig. 1 7-30 PA stomach and duodenum.

Fig. 1 7-31 Single-contrast PA stomach and duodenum. 1 42

Fig. 1 7-32 Double-contrast PA stomach and duodenum.

Stomach and Duodenum

The pyloric canal and duodenal bulb are well demonstrated in patients with an asthenic or a hyposthenic habitus. These structures are often partial ly obscured in patients with a sthenic habitus and, except in the angled position, are completely ob­ scured by the prepy loric portion of the stomach in patients with a hypersthenic habitus.

EVALUATION CRITERIA

The followi ng should clearl y be demon­ strated: • Entire stomach and duodenal loop • Stomach centered at the level of the pylorus.

• •

No rotation of the patient Exposure technique that demonstrates the anatomy

NOTE: A 35 x 43 cm IR is often used when the distal esophagus or the smal l bowel is to be vi­ sualized along with the stomach.

Fig. 1 7-33 Hypersthenic patient.

Fig. 1 7-34 Sthenic patient.

Fig. 1 7-35 Hyposthenic patient.

Fig. 1 7-36 Asthenic patient. 1 43

Stomach and Duodenum

PA AXIAL PROJECTION

•

Image receptor: 35 x 43 cm length­

wise Position of patient •

Place the patient in the prone position.

• •

Position of part •

Adjust the patient's body so that the midsagittal plane is centered to the grid.

For the sthenic patient, center the IR at the level of L2 (Fig. 1 7-37) ; center it somewhat higher for the hypersthenic patient and somewhat lower for the as­ thenic patient. L2 will l ie about 1 -2 i nches above the lower rib margin. Shield gonads. Respiration.: S uspend respiration at the end of expiration u n less otherw i se requested.

Fig.

1 44

Central ray •

Directed to the midpoint of the I R at an angle of 35 to 45 degrees cephalad. Gugliantinil recommended a cephalic an­ gulation of 20 to 25 degrees for demon­ stration of the stomach in infants.

'Gugliantini P: Utilita delle incidenze oblique cau­ docraniali nello studio radiologico della stenosi con­ genita ipertrofica del pi loro, Ann Radiol [Diagn) 34:56, 1 96 1 . Abstract, Am J Roelllgeno/ 87:623, 1 962.

1 7-37 PA axial stomach.

Stomach and Duodenum

EVALUATION CRITERIA

Structures shown

Gordon' developed the PA axial projec­ tion to "open up" the hjgh, horizontal (hypersthenic-type) stomach for demon­ stration of the greater and lesser curva­ tures, the antral portion of the stomach, the pyloric canal , and the duodenal bulb. The resultant image gives the hyper­ sthenic stomach much the same configu­ ration as the average sthenic type of stom­ ach ( Fig. 1 7-38).

The fol lowing should clearly be demon­ strated: • Entire stomach and proximal duodenum • Stomach centered at the level of the pylorus • Exposure technique that demonstrates the anatomy

'Gordon SS: The angled posteroanterior projection of the stomach: an attempt at better visualization of the high transverse stomach. Radiology 69:393. 1 957.

Fundus !----.::.---=.;;"

Body t-;:,-----''--= Lesser curvature

..,=;:;:::"=

Greater curvature

Pyloric region

Fig. 1 7 -38 PA axial stomach. Sthenic habitus.

1 45

Stomach and Duodenum

.. PA OBLIQUE PROJECTION RAO position

Image receptor:

Position of part •

30 x

35 cm

lengthwise •

Position of patient •

Place the patient in the recumbent po­ sition.

•

•

After the PA projection, i nstruct the pa­ tient to rest the head on the right cheek and to place the right arm along the side of the body. Have the patient raise his or her left side and support the body on the left forearm and flexed left knee. Adjust the patient's position so that a sagittal plane passing midway between the vertebrae and the lateral border of the elevated side coincides with the midl ine of the grid (Fig. 1 7-39). Center the JR about I to 2 i nches above the lower rib margin at the level of L J ­ L2 when the patient is prone. Make the fi nal adjustment in body rota­ tion. The approximately 40 to 70 de­ grees of rotation required to give the best i mage of the pyloric canal and duodenum depend on the size, shape, and position of the stomach. In general, hypersthenic patients require a greater degree of rotation than do sthenic and asthenic patient .

• •

The RAO posItIon is used for serial studies of the pyloric canal and the duo­ denal bulb because gastric peristalsis is usually more active when the patient is in this position. Shield gonads. Respiration: Suspend at the end of ex­ piration unles otherwise requested.

Central ray •

Perpendicular to the center of the I R

Fig. 1 7-39 PA oblique stomach and duodenum. and duodenum RAO position.

1 46

Stomach and Duodenum

Structures shown

A PA oblique projection of the stomach and entire duodenal loop is presented. This projection gives the best image of the pyloric canal and the duodenal bulb in pa­ tients whose habitus approxi mates the sthenic type ( Figs. 1 7-40 and 1 7-4 1 ). Because gastric peristalsis is general ly more active with the patient in the RAO position, a serial study of several expo­ sures is sometimes obtained at intervals of 30 to 40 seconds for del i neation of the py­ loric canal and duodenal bulb.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Entire stomach and duodenal loop • No superimposition of the pylorus and duodenal bulb • Duodenal bulb and loop in profile • Stomach centered at the level of the pylorus • Exposure technique that demonstrates the anatomy

Fundus

Greater curvature

Duodenal bulb

Pylorus

Fig. 1 7 -40 Single-contrast PA oblique stomach and duo­ denum. RAO position.

Fig. 1 7-41 Double-contrast PA oblique stomach and duodenum. Note esophagus entering stomach (arrow).

1 47

Stomach and Duodenum

..

AP OBLIQUE PROJECTION LPO position Image receptor: 30

Position of part •

x

35 cm

lengthwise

•

Position of patient

•

•

Place the patient in the supine position. •

•

•

Have the patient abduct the left arm and place the hand near the head, or place the extended arm alongside the body. Place the right arm alongside the body or across the upper chest, as preferred. Have the patient tum toward the left, rest­ ing on the left posterior body surface. Flex the patient's right knee, and rotate the knee toward the left for support. Place a positioning sponge against the patient's elevated back for immobil iza­ tion. Adj ust the patient's position so that a sagittal plane passi ng approximately midway between the vertebrae and the left lateral margin of the abdomen is centered to the I R.

•

•

•

Adjust the center of the IR at the level of the body of the stomach. The center­ i ng will be at a point midway between the xiphoid process and the lower mar­ gin of the ribs (Fig. 1 7-42). The degree of rotation required to best demonstrate the stomach depends on the patient's body habitus. An average angle of 45 degrees should be sufficient for the sthenic patient, but the degree of angulation can vary from 30 to 60 degrees. Shield gonads. Respiration: Suspend at the end of ex­ piration unless otherwise i nstructed.

Fig. 1 7-42 AP oblique stomach and duodenum. LPO position.

1 48

Stomach and Duodenum

EVALUATION CRITERIA

Central ray •

Perpendicu lar to the center of the J R.

Structures shown

The AP oblique projection demonstrates the fundic portion of the stomach ( Fig. 1 7-43). Because of the effect of gravity, the pyloric canal and duodenal bu lb are not as fi l led with barium as they are in the opposite and complementary position (the RAO position; see Figs. 1 7-39 to 1 7-4 1 ).

The fol lowi ng should be clearly demon­ strated: • Entire stomach and duodenal loop • Fundic portion of stomach • No superi mposition of the pylorus and duodenal bulb • Body of the stomach centered to the radiograph • Exposure technique that demonstrates the anatomy • Body and pylorus with double-contrast visualization

Esophagus Fundus

Body --===

Duodenum

-----:-'--

Fig. 1 7-43 Double-contrast AP oblique stomach and duodenum, LPO position.

1 49

Stomach and Duodenum

.. LATERAL PROJECTION

Image receptor: 30

lengthwise

•

x

Position of part

Position of patient

R position 35 cm

Place the patient in the upright left­ lateral position for demonstration of the left retrogastric space and in the re­ cumbent right-lateral position for demonstration of the right retrogastric space, duodenal loop, and duodenojeju­ nal junction.

•

•

• •

With the patient in either the upright or recumbent position, adj ust the body so that a plane passing midway between the midcoronal plane and the anterior surface of the abdomen coincides with the midli ne of the grid. Center the IR at the level of L l -L2 for the rec umbent position (about 1 -2 inches above the lower rib margin) and at L3 for the upright position. Adjust the body i n a true lateral posi­ tion (Fig. 1 7-44). Shield gonads. Respiration: Suspend at the end of ex­ piration unless otherwise requested.

Fig. 1 7-44 Right lateral stomach and duodenum.

1 50

Stomach and Duodenum

Central ray •

Perpendicular to the center of the IR.

Structures shown

A lateral projection shows the anterior and posterior aspects of the stomach, the py­ loric canal, and the duodenal bulb (Figs. 1 7-45 and 1 7-46). The right lateral projec­ tion commonl y affords the best i mage of the pyloric canal and the duodenal bulb in patients with a hypersthenic habitus.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Entire stomach and duodenal loop • No rotation of the patient, as demon­ strated by the vertebrae • Stomach centered at the level of the pylorus • Exposure technique that demonstrates the anatomy

Fundus

Body Duodenum Duodenal bulb

Pyloric portion

Fig. 1 7-45 Single-contrast right lateral stomach and duodenum.

Fig. 1 7-46 Double-contrast right lateral stomach and duodenum.

1 51

Stomach and Duodenum

.. AP PROJECTION Image receptor: 30 x 35 cm cross­

wise for the stomach and duodenum, lengthwise for small hjatal hernias; 35 X 43 cm lengthwise for large di­ aphragmatic herniations or for the stomach and small bowel. Position of patient •

•

Place the patient in the supine position. The stomach moves superiorly and to the left in this position, and except in thin patients, i ts pyloric end is elevated so that the barium flows into and fills its cardjac and/or fundic portions. The fi l l­ ing of the fundus displaces the gas bub­ ble into the pyloric end of the stomach, where it allows double-contrast delin­ eation of posterior wal l lesions when a single-contrast examination is per­ formed. If the patient is thin, the intesti­ nal loops do not move superior enough to tilt the stomach for fundic filling. It is therefore necessary to rotate the pa­ tient's body toward the left or to angle the head end of the table downward. Ti l t t he table to ful l or part ial Trendelenburg angulation for the demonstration of diaphragmatic hernia­ tions (Fig. 1 7-47) . In the Trendelenburg position, the involved organ or organs, which may appear to be normally lo­ cated in all other body positions, shift upward and protrude through the her­ nial orifice (most commonly through the esophageal hiatus).

•

• •

Adj ust the position of the patient so that the midline of the grid coincides ( I ) with the midl ine of the body when a 35 X 43 cm IR is used (Figs. 1 7-47 and 1 7-48) or (2) with a sagittal plane pass­ i ng midway between the midline and the left lateral margin of the abdomen w hen a 30 X 35 cm I R is used. Longitudinal centering of the l arge IR depends on the extent of hernial protru­ sion into the thorax and is determined during fluoroscopy. For the stomach and duodenum, center the 30 X 35 cm IR at a level midway be­ tween the xiphoid process and the lower rib margin (approximately L 1 -L2). For the 35 X 43 cm I R center at the same level and adjust up or down slightly de­ pending on whether the diaphragm or small bowel needs to be seen. Shield gonads. Respiration: S uspend at the end of ex­ piration unless otherwise requested.

Central ray •

Perpendicular to the center of the IR.

Fig. 1 7-47 AP stomach and duodenum with table in partial Trendelenburg position. 1 52

Structures shown

Position of part •

Stomach

An AP projection of the stomach shows a well-filled fundic portion and usually a double-contrast delineation of the body, py­ loric portion, and duodenum (Fig. 1 7-49). Because of the elevation and superior dis­ placement of the stomach, this projection affords the best AP projection of the retro­ gastric portion of the duodenum and jejunum. Diaphragm

An AP projection of the abdominotho­ racie region demonstrates the organ or or­ gans involved in, and the location and ex­ tent of, any gross hern ial protrusion through the diaphragm (Fig . 1 7-50 and 1 7-5 1 ).

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Entire stomach and duodenal l oop • Double-contrast visualization of the gastric body, pylorus, and duodenal bulb • Retrogastric portion of the duodenum and jejunum • Lower l ung fields on 35 X 43 cm radio­ graphs for demonstration of diaphrag­ matic hernias • Stomach centered at the level of the py­ lorus on 30 X 35 cm radiographs • No rotation of the patient • Exposure technique that demonstrates the anatomy

Fig. 1 7-48 AP stomach and duodenum.

Stomach and Duodenum

Fundus

Body Pyloric portion Duodenal loop

Fig. 1 7-49 AP stomach and duodenum. Sthenic habitus.

Esophagus Fundus

Lung Duodenum

Fig. 1 7-50 vAP stomach and duodenum. showing hiatal hernia above the level of the diaphragm (arrow).

Fig. 1 7-51 Upright left lateral stomach showing hiatal hernia. (Comparison lateral radiographs are shown in Figs. 1 7-45 and 1 7-46.) 1 53

Superior Stomach and Distal Esophagus

PA OBLIQUE PROJECTION WOLF METHOD' (FOR HIATAL HERNIA) RAO position

Image receptor: 35 x 43 cm length­

wise The Wolf method' is a modification of the Trendelenburg position . The technique was developed for the purpose of applying greater intraabdomi nal pressure than is provided by body angulation alone and thereby ensuring more consistent results i n the radiographic demonstration of small, sliding gastroesophageal hernia­ tions through the esophageal hiatus. The Wol f method requires the use of a emicyl i ndrical radiolucent compression device measuring 22 inches (55 cm) in length, 10 inches (24 cm) in width, and 8 i nches (20 cm) in height. (The compression sponge depicted in Fig. 1 7-52 is slightly smaller than the one described by Wolf.)

Wol f and Guglielm02 stated that this compression device not only provides Trendelenburg angulation of the patient's trunk but also i ncreases intraabdominal pressure enough to permit adequate con­ trast fi lling and maximum distention of the entire esophagus. A further advantage of the device is that it does not require an­ gulation of the table; thus the patient is able to hold the bari um container and in­ gest the barium suspension through a straw with comparative ease. 'Wolf BS, Guglielmo J: The roentgen demonstration of minimal hiatus hernia, Med Radiogr Phofogr 33 :90, 1 957.

Position of patient •

Place the patient in the prone position on the radiographic table.

Position of part •

•

•

•

•

• •

Instruct the patient to assume a modi­ fied knee-chest position during place­ ment of the compression device. Place the compression device horizon­ tally under the abdomen and just below the costal margin . Adjust the patient in a 40- to 45-degree RAO position, with the thorax centered to the midl i ne of the grid . I nstruct the patient to i ngest the bari um suspension i n rapid, continuous swal­ lows. To allow for complete filling of the esophagus, make the exposure during the third or fourth swallow (see Fig. 1 7-52). Shield gonads. Respiration: Suspend at the end of ex­ piration.

' Wolf BS. Guglielmo J : Method for the roentgen demonstration of minimal hiatal herniation, J MI Sinai Hosp NY 23:738, 741 , 1 956.

Fig. 1 7-52 PA oblique stomach with compression sponge, RAO position.

1 54

Superior Stomach and Distal Esophagus

Central ray •

Perpendicular to the long axis of the pa­ tient's back and centered at the level of either T6 or n. This position usual ly results i n a 1 0- to 20-degree caudad an­ gulation of the central ray.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • M iddle or distal aspects of the esopha­ gus and the upper aspect of the stomach • Esophagus visible between the verte­ bral column and the heart

Structures shown

The Wolf method demonstrates the rela­ tionship of the stomach to the diaphragm and is useful in diagnosing a hiatal hernia (Fig. 1 7-53).

A

B

Fig. 1 7 -53 Comparison PA axial oblique images in one patient. A, Without abdominal compression: no evidence of hernia. B, With abdominal compression: obvious large slid­ ing hernia (arrow).

1 55

Stomach and Duodenum: Serial and Mucosal Studies

PA OBLIQUE PROJECTION

•

RAO position

Some i nstitutions obtain radiographs specifically to demonstrate the gastric mucosa after the fl uoroscopic examina­ tion. A pneumatic paddle may be used (Fig. l 7-54). The paddle is fl uoroscopi­ cal ly positioned under the area of the py­ loric sphincter and duodenal bulb. A radi­ ograph is obtained with the pneumatic paddle i n flated, and add itional radi­ ographs are taken as the paddle is de­ flated. The fl uoroscopic portion of this ex­ amination i performed by the radiologist.

•

•

• •

After the fluoroscopic adjustments, po­ sition the x-ray tube over the patient, and expose postfluoroscopic i mages. Place the IR in the B ucky tray, and cen­ ter it to the paddle. For subsequent exposures, change the IR. Shield gonads. Respiration: Suspend at the end of ex­ piration unless otherwise requested.

Central ray •

Perpendicular to the I R

Structures shown

This method demonstrates a compression and a noncom pression study of the pyloric end of the stomach and the duodenal bulb at different stages of fill ing and emptying. A compression study of the mucosa of a localized area of the gastrointestinal tract is also shown (Fig. 1 7-56). EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Pylorus and duodenal bulb centered, free of superimposition, and in profile

Position of patient •

•

Place the patient i n a prone and s lightly RAO position, and center the region to be studied to approximately the midline of the grid. Place an i nflatable paddle under the area of i nterest.

Position of part •

•

Under fl uoroscopic control, adjust the patient so that the area of the duodenal bulb is centered to the paddJe. For a mucosal study, inflate the com­ pression bladder of the paddle to pro­ vide the desired degree of pressure (Figs. l 7-54 and 1 7-55).

Fig. 1 7-54 PA oblique pylorus and duodenal bulb with compression paddle, RAO position.

Fig. 1 7-55 Compression paddle: inftated (above): noninftated (be/ow).

1 56

Fig. 1 7-56 Serial compression study showing varying degrees of compression and the value of compression paddle in demon­ strating duodenal bulb.

Small Intestine Radiologic examinations of the small in­ testine are performed by admjnistering a barium sulfate preparation ( l ) by mouth, (2) by complete reflux filling with a l arge­ volume barium enema, or (3) by direct in­ jection into the bowel through an intestinal tube, a technique that is calJed entero­ clysis, or small intestine enema. The latter two methods are usually used only when the oral method fruls to provide conclusive information. I

PREPARATION FOR EXAMINATION It is preferable for the patient to have a soft or low-residue diet for 2 days before the small intestine study. Because of econom­ ics, however, it often is not possible to de­ lay the examjnation for 2 days. Therefore food and fluid are usually withheld after the evening meal of the day before the ex­ amination, and breakfast is withheld on the day of the study. A cleansing enema may be administered to clear the colon; how­ ever, an enema is not always recom­ mended for enteroclysis because enema fluid may be retruned in the small intestine. The barium formula varies, depending on the method of examjnation. The patient's bladder should be empty before and during the procedure to avoid displacing or com­ pressing the i leum.

ORAL METHOD OF EXAM INATION The radiographic examination of the small intestine is usually termed a small boweL series since several identical radi­ ographs are done at timed intervals. The oral examination, or ingestion of barium through the mouth, i s usually preceded by a preliminary radiograph of the abdomen. Each radiograph of the small intestine is identified with a time marker indicating the interval between its exposure and the ingestion of barium. The studies are made with the patient in either the supine or prone position. The supine position is used ( I ) to take advantage of the superior and lateral shift of the barium-filled stom­ ach for visualization of the retrogastric portions of the duodenum and jejunum and (2) to prevent possible compression overlapping of loops of the intestine. The prone position is used to compress the ab­ dominal contents, which increases radio­ graphic quality. For the final radiographs in thi n patients, it may be necessary to an­ gIe the table into the Trendelenburg posi­ tion to "unfold" low-lying and superim­ posed loops of the ileum.

The first smaU intestine radiograph is usually taken 1 5 minutes after the patient drinks the barium. The interval to the next exposure varies from 1 5 to 30 mjnutes de­ pending on the average transit time of the barium sulfate preparation used. Regardless of the barium preparation used, the radiolo­ gist inspects the radiographs as they are processed and varies the procedure accord­ ing to the requirements for the individual patient. Fluoroscopic and radiographic studies (spot or conventional) may be made of any segment of the bowel as the loops become opacified. Some radiologists request that a glass of ice water (or other routinely used food stimulant) be given to the patient with hy­ pomotility after 3 or 4 hours of adminis­ trating barium sulfate to accelerate peri­ stal sis. Others give patients a water­ soluble gastrointestinal contrast medjum, tea, or coffee to stimulate peristalsis. Sti l l others admjnister peri staltic stimulants every 1 5 mjnutes through the transit time. With these methods, the transit of the medium is demonstrated fluoroscopical ly, spot and conventional radiographs are ex­ posed as indicated, and the examj nation is usually completed in 30 to 60 minutes.

' Fitch D: The small-bowel see-through: an improved method of radiographic small bowel visualization, Can J Med Rad TechnoI 26(4): 1 67, 1 995.

1 57

Small I ntestine

..

PA OR AP PROJECTION Image receptor: 35

x 43 cm

lengthwise Position of patient •

Place the patient in the prone or supine position.

Position of part •

•

•

• •

Adj ust the patient so that the midsagit­ tal plane is centered to the grid. For the sthenic patient, center the IR at the level of L2 for radiographs taken within 30 minutes after the contrast medium is administered ( Fig. 1 7-57). For delayed radiographs, center the IR at the level of the il iac crests. Shield gonads. Respiration: Suspend at the end of ex­ piration unless otherwise requested.

EVALUATION CRITERIA

Structures shown

The PA or AP projection demonstrates the small intestine progressively fi l l i ng unti l the barium reaches the ileocecal valve (Figs. 1 7-58 to 1 7-65 ). When the barium has reached the ileo­ cecal region, fl uoroscopy may be per­ formed and compression radiographs ob­ tained (Fig. 1 7-66). The examination is usually completed when the barium is visualized in the cecum.

The following should be clearly demon­ strated: • Entire small i ntestine on each i mage • Stomach on i nitial images • Time marker • Vertebral column centered on the radi­ ograph • No rotation of the patient • Exposure technique that demonstrates the anatomy • Complete examination when barium reaches the cecum

Central ray •

Perpendicular to the midpoint of the I R (L2) for early radiographs o r a t the level of the i liac crests for delayed se­ quence exposures

Fig. 1 7-57 AP small intestine.

1 58

Fig. 1 7-58 Immediate AP small intestine.

Small I ntestine

Fig. 1 7-59 AP small intestine at 15 minutes.

Fig. 1 7-60 AP small intestine at 30 minutes, showing stomach (st) and small intestine (si).

Fig. 1 7-61 AP small intestine at 1 hour.

Fig. 1 7-62 AP small intestine at 2 hours, showing small i ntestine (s) and colon (c).

1 59

Small Intestine

Fig. 1 7-64 AP small intestine at 4'/2 hours.

Fig. 1 7-63 AP small intestine at 3'/2 hours with barium in colon.

Ileocecal valve Cecum Appendix Ileum

Fig. 1 7-65 AP small intestine at 24 hours.

1 60

Fig. 1 7-66 Ileocecal studies.

Smcll intestine

COMPLETE REFLUX EXAMI NATION

E NTEROCLYSIS PROCEDURE

For a complete reflux examination of the small i ntestine, 1 .2 the patient's colon and small i ntestine are filled by administeri ng a barium enema to demonstrate the colon and small bowel . Before the exami nation, glucagon may be administered to relax the i ntestine. Diazepam (Valium) may also be given to dimi nish patient discomfort dur­ i ng the initial fil l i ng of the bowel . A 1 5% ± 5% weight/volume barium suspension is often used, and a large amount of the suspension (about 4500 ml) is required to fi l l the colon and small i ntestine. A retention enema tip is used, and the patient is placed in the supine position for the examination. The barium suspension i allowed to flow until it is observed i n the duodenal bulb. The enema bag is then lowered to the floor to drain the colon be­ fore radiographs of the small i ntestine are obtained (Fig. 1 7-67).

Enteroclysis (the i njection of nutrient or medicinal liquid i nto the bowel ) is a radio­ graphic procedure i n which contrast medium is i njected i nto the duodenum un­ der fluoroscopic control for examination of the small intestine. The contrast medium is i njected through a Bilbao or Sel link tube. Before the procedure is begun, the pa­ tient's colon must be thoroughly cleansed. Enemas are not recommended as prepara­ tion for enteroclysis because some enema fluid may be retained in the small i ntes­ tine. Under fluoroscopic control, a B i l bao or Sell ink tube with a tiff guide wire is advanced to the end of the duodenum at the duodenojejunal flexure, near the l iga­ ment of Treitz. Barium is then i nsti l led through the tube at a rate of approxi­ mately 1 00 mllminute ( Fig. 1 7-68) . Spot radiographs, with and without compres­ sion, are taken as required. In some pa­ tients, air or methylcellulose is i njected i nto the small i ntestine after the contrast fl uid has reached the cecum (Fig. 1 7-69).

I M iller R E : Complete reflux small bowel examina­ tion, Radiology 84:457, 1 965. ' M i l ler RE: Localization of the small bowel hemor­ rhage; complete reflex small bowel examination, Am J Dig Dis 1 7 : 1 0 1 9, 1 972.

After fluoroscopic examination of the patient's small intestine, radiographs of the small intestine may be requested. The pro­ jections most often requested include the AP, PA, obliques, and lateral . Both recum­ bent and upright images may be requested. (positioning descriptions involving the ab­ domen are presented in Chapter 1 6.)

Fig. 1 7-67 Normal retrograde reftux exami­ nation of small intestine.

Sellink tube

Barium in colon

Barium In colon

Barium/air In small Intestine Small intestine Terminal ileum

Fig. 1 7-68 Enteroclysis procedure with barium visualized in colon.

Fig. 1 7-69 Air-contrast enteroclysis. 161

Small I ntestine

INTUBATION EXAMI NATION PROCEDURES Gastrointestinal intubation is the proce­ dure in which a long, specifically designed tube is inserted through the nose and pa sed into the stomach. From there the tube is carried inferiorly by peristaltic ac­ tion. Ga trointestinal intubation is used for both therapeutic and diagnostic purposes. W hen gastroi ntesti nal intubation is used therapeutical ly, the tube is connected to a suction system for continuous siphon­ ing of the gas and fluid contents of the gastroi ntestinal tract. The purpose of the maneuver is to prevent or relieve postop­ erative distention or to deflate or decom­ press an obstructed smal l intestine.

1 62

Although used much less frequently than in the past, a Miller-Abbott (M-A ) double-lumen, single balloon tube (or other simi lar tubing) can be used to intu­ bate the small intestine. Just above the tip of the M-A tube is a small, thin rubber balloon. Marks on the tube, beginning at the distal end, indicate the extent of the tube's passage and are read from the edge of the nostril . The marks are graduated i n centimeters u p t o 8 5 and are given in feet thereafter. The lumen of the tube is asym­ metrically divided i nto the fol lowing: ( I ) a small balloon lumen that communicates with the balloon only and is used for the inflation and deflation of the balloon and for the injection of mercury to weight the balloon and (2) a large aspiration lumen that communicates with the gastroi ntesti­ nal tract through perforations near and at the distal end of the tube. Gas and fluids are withdrawn through the aspiration lu­ men, and liquids are injected through it.

The introduction of an intestinal tube is an unpleasant experience for the patient, especially one who is acutely ill. Depend­ ing on the condition of the patient, the tube is more readily passed if the patient can sit erect and lean slightly forward or if the patient can be elevated almost to a itting position. With the i ntestinal tube in place, the pa­ tient is turned to an RAO position, a sy­ ringe is connected to the balloon lumen, and the mercury is poured into the syringe and allowed to flow into the balloon . The air is then slowly withdrawn from the bal­ loon. The tube is secured with an adhesive strip beside the nostril to prevent regurgi­ tation or advancement of the tube. The stomach is aspirated, either by syringe or by attaching the l arge position of the lu­ men to the suction apparatus. With the tip of the tube situated close to the pyloric sphincter and the patient in the RAO position (a position i n which gastric peristalsis is usually more active), the tube should pass into the duodenum in a rea­ sonably short time. Without intervention, however, this process sometimes takes many hours. Having the patient dri nk ice water to stimulate peristalsis is often suc­ cessful. When this measure fails, the ex­ aminer guides the tube into the duodenum by manual manipulation under fl uoro­ scopic observation. After the tube enters the duodenum, it is again inflated to pro­ vide a bolus that the peristaltic waves can more readily move along the intestine.

Small Intestine

When the tube is i nserted for decom­ pression of an i ntestinal obstruction and possible later radiologic i nvestigation, the adhesive strip is removed and replaced with an adhesive loop attached to the fore­ head. The tube can slide through the loop without tension as it advances toward the obstructed site. The patient is then re­ turned to the hospital room. Radiographs of the abdomen may be taken to check the progress of the tube and the effectiveness of decompression. Simple obstructions are sometimes relieved by suction; others require surgical i ntervention.

If the passage of the i ntestinal tube is arrested, the suction i s discontinued and the patient is returned to the radiology de­ partment for an M-A tube study. The con­ trast medium used for studies of a local­ ized segment of the small i ntestine may be either a water-sol uble, iodinated solution (Fig. 1 7-70) or a thjn barium sulfate sus­ pension. Under fluoroscopic observation the contrast agent is i njected through the large lumen of the tube with a syringe. Spot and conventional radiographs are ob­ tained as indicated.

Fig. 1 7-70 Miller-Abbott eM-A) tube study with water-soluble medium.

When the intestinal tube is introduced for the purpose of performing a small in­ testine enema, the tube is advanced into the proxi mal loop of the jejunum and then secured at this level with an adhesive strip taped beside the nose. Medical opinion varies as to the quantity of barium suspen­ sion required for this examination (Fig. 1 7-7 1 ). The medium i s injected through the aspiration l umen of the tube in a con­ tinuous, low-pressure flow. Spot and con­ ventional radiographs are exposed as indi­ cated. Except for the presence of the tube in the upper jejunum, the resultant radi­ ographs resemble those obtained by the oral method.

Fig. 1 7- 7 1 Small bowel examination by M-A tube with injection barium sulfate.

1 63

Large I ntestine CONTRAST STUDIES There are two basic radiologic methods of examining the l arge intestine by means of diagnostic or contrast enemas the: ( I ) the single-con.trast method ( Fig. 1 7-72), in which the colon is examined with a bar­ ium sulfate suspension only, and (2) the double-contrast method ( Fig. 1 7-73), which may be performed as a two-stage or single-stage procedure. In the two-stage double-contrast procedure, the colon is examined with a barium sulfate suspen­ sion and then, immediately after evacua­ tion of the barium suspension, with an air enema or another gaseous enema. In the single-stage doubLe-contrast procedure the fluoroscopist selectively i njects the barium uspen ion and the gas. The contrast medium demonstrates the anatomy and tonus of the colon and most of the abnormalities to which it is subject. The gaseous medium serves to distend the l umen of the bowel and to render visible, through the transparency of its shadow, all parts of the barium-coated mucosal l i ning of the colon and any small i ntral umi nal le­ sion , such as polypoid tumors.

Contrast media

Specifical ly prepared water-sol uble, io­ Commercially prepared barium sulfate dinated contrast agents are administered products are generally used for routine ret­ orally to selected patients when retrograde rograde examinations of the large intestine. fil l ing of the colon with barium is not pos­ Some of these products are referred to as sible or is contraindicated. A disadvantage coLLoidal preparations because they have of the iodinated sol utions is that evacua­ finely divided barium particles that resist tion often is i nsufficient for satisfactory precipitation, whereas others are referred double-contrast visualization of the mu­ to as suspended or floccuLation-resistant cosal pattern. However, when a patient is preparations because they contain some unable to cooperate for a successful en­ form of suspending or dispersing agent. ema study, orally administered iodinated The newest barium products avai l able medium al lows satisfactory examination are referred to as high-density barium of the colon. With these oral agent, transit sulfate. These products absorb a greater time from i ngestion to colonic filling is percentage of radiation, similar to the fast, averaging 3 to 4 hours. Furthermore, older "thick" barium products. H igh­ iodi nated solutions are practically no nab­ density barium is particularly useful for sorbable from the gastrointestinal mu­ double-contrast studies of the alimentary cosa. As a result, the oral dose reaches and canal i n which uniform coati ng of the lu­ outlines the entire l arge bowel. Unli ke an i ngested barium sulfate suspension, this men is required. Air is the gaseous medium usually used medium is not subject to drying, flaking, in the double-contrast enema study. There­ and unequal distribution in the colon. fore the procedure is generally called an Therefore it frequently delineates the in­ air-contrast study. Carbon dioxide may also testine almost as well as the barium en­ be used because it is more rapidly absorbed ema does. than the nitrogen in air when evacuation of the gaseous medium is incomplete.

Fig. 1 7-72 Lorge intestine, Single-contrast study.

1 64

Fig. 1 7-73 Lorge intestine, double-contrast study.

Preparation of intestinal tract

Standard barium enema apparatus

Medical opinion about preparation mea­ sures varies. However, members of the medical profession usually agree that the large intestine must be completely emp­ tied of its contents to render all portions of its inner wall visible for inspection. When coated with a barium sulfate suspension, retained fecal masses are likely to simu­ late the appearance of polypoid or other small tumor masses (Fig. 1 7-74). This makes thorough cleansing of the entire colon a matter of prime i mportance. Preliminary preparation of the intestinal tract of patients who have a condition such as severe diarrhea, gross bleeding, or symptoms of obstruction is, of course, li mited. Other patients are prepared, with modification as indicated, according to the specifications established by the ex­ amining physician. The pre l i m i nary preparation usually includes dietary re­ strictions and a laxative. Cleansing ene­ mas are also used, as are commercially available complete colon cleansing kits designed for easy use by outpatients or hospital nursing personnel .

Disposable soft plastic enema tips and en­ ema bags are commercially available in different sizes. A soft rubber rectal catheter of small caliber should be used in patients who have inflamed hemorrhoids, fissures, a stricture, or other abnormalities of the anus. Disposable rectal retention tips (Fig. 1 7-75) have replaced the older retention catheters such as the B ardex or Foley catheter. The retention tip is a double­ lumen tube with a thin balloon at its distal end. Because of the danger of intestinal rupture, the retention tip must be inserted with extreme care. The enema retention tip is used i n the patient who has a relaxed anal sphincter or another condition that makes it difficult or impossible to retain an enema. Some radiologists routinely use retention enema tips and inflate them if necessary.

Fig. 1 7-74 Single-contrast barium-filled colon, showing fecal ma­ terial that simulates or masks pathologiC condition (arrows).

The disposable rectal retention tip has a balloon that fits snugly against the enema nozzle both before and after deflation so that it can be inserted and removed with little discomfort to the patient. A reusable squeeze inflator is recommended to J jmit the air capacity to approxi mately 90 ml. One complete squeeze of the inflator pro­ vides adequate distention of the retention balloon without danger of overinflation. Disposable retention tips are available for both double-contrast and single-contrast enemas. For the safety of the patient, any retention balloon must be inflated with caution, using fluoroscopy, just before the examination.

Fig. 1 7-75 Disposable retention enema tip. Uninftated balloon fits snugly. Inset: Balloon inftated with 90 ml of air (one complete squeeze of inftator),

1 65

For the performance of a double-con­ trast barium enema ( BE) exami nation, a special rectal tip is needed to insti l l air i n the colon (Fig. 1 7-76). Alternatively, air can simply be pumped i nto the colon us­ i ng a sphygmomanometer bulb. Double­ contrast retention tips are also available. Most enema bags have a capaci ty of 3 quarts (3000 ml) when ful ly distended and have graduated quantity markings on the side. A fi lter may be incorporated within the bag to prevent the passage of any un­ mi xed l umps of barium. The tubing is ap­ proximately 6 feet long. Preparation of barium suspensions

The concentration of the bari um sulfate suspensi ons used for si ngle-contrast colonic enemas varies considerably. The often recommended range is between 1 2% to 25% for weight/volume. For double­ contrast examinations, a relatively high­ density barium product is used. A 75% to 95% weight/vol ume ratio is common. Commercial bari um enema prepara­ tions are available as premixed l iquids that can be poured into the disposable en­ ema kit bag. Powdered barium is al 0 available in single-contra t disposable kit bags. Water is added, and the solution is mixed by shaki ng the bag.

I nstructions for mixing a barium prepa­ ration vary according to the manufacturer and the type of barium used. The best rec­ ommendation is to fol low the manufac­ turer's instructions precisely. If warm barium enemas are admini s­ tered, the temperature should be some­ what below body temperature-about 85° to 90° F (29° to 30° C). I n addition to be­ i ng unpleasant and debilitati ng, an enema that is too warm is inj urious to i ntestinal tissues and produces so much irritation that it is diffic ult, if not impossible, for the patient to retai n the enema long enough for a satisfactory examination. Cold barium enema suspensions (4 1 ° F [5° C]) have been recommended I on the basis that the colder temperature produces less irritation, has a mild anesthetic effect that relaxes the colon, and stimulates tonic contraction of the anal sphincter. These effects result in greater comfort and ease of retention for the patient and permit easier, more rapid fil ling of the colon. The patient not only has no sensation of chill but also finds the cold suspension soothi ng and easy to retain. The cold temperature is most easi ly obtained by prepari ng the bar­ ium suspension one day i n advance and refrigerati ng it overnight. ' Levene G: Low temperature bariul11-water suspen­ sions for roentgenologic examination of the colon, Radiology 77: 1 1 7, 1 96 1 .

Preparation and care of patient

In no radiologic examination is the ful l cooperation of the patient more essential to success than in the retrograde exami na­ tion of the colon. Few patients who are physically able to retain the enema fai l to do so when they understand the procedure and realize that in l arge measure the suc­ cess of the examination depends on them. The radiographer should observe the fol ­ lowing guidelines in prepari ng a patient for retrograde examination of the colon: Take time to explain the procedural dif­ ferences between an ordinary c leansing enema and a diagnostic enema: ( I ) with the diagnostic enema the fluoroscopist exami nes all portions of the bowel as it is being fi lled with contrast medium un­ der fluoroscopic observation; (2) this part of the examination involves palpa­ tion of the abdomen, rotation of the body as required to visual ize the differ­ ent segments of the colon, and the tak­ ing of spot radiographs without and, when indicated, with compression; ( 3 ) a eries of large radiographs are taken before the colon can be evacuated ( Fig. 1 7-77). Assure the patient that retention of the diagnostic enema preparation will be comparatively easy because its flow is controlled under fluoroscopic observa­ tion. Instruct the patient ( l ) to keep the anal sphincter tightly contracted against the tubing to hold it in position and prevent leakage, (2) to relax the abdominal mus­ cles to prevent i ntraabdominal pressure, and (3) to concentrate on deep oral breathing to reduce the i ncidence of colonic spasm and resultant cramp . Assure the patient that the flow of the enema will be stopped for the duration of any cramping. •

•

•

•

Fig. 1 7-76 Air-contrast enema tip shown with the air tube filled with ink to demonstrate position.

1 66

The patient who has not had a previous colonic examination is usual ly fearful of being embarrassed by inadequate draping and failure to retain the enema for the re­ quired time. The radiographer can di pel or greatly relieve the patient's anxiety by observi ng the fol lowi ng steps: A sure the patient that he or she will be properly covered. Assure the patient that although there is little chance of "mishap," he or she will be well protected but that there is no need to feel embarrassed should one occur. Keep a bedpan in the examining room for the patient who cannot or may not be able to make the trip to the toilet. •

•

•

The prelimi nary preparation required for a retrograde study of the colon is strenuous for the patient. The examination itself further depletes the patient's strength. Feeble patients, particularly el­ derly persons, are l ikely to become weak and fai n t from the exertion of the prepara­ tion, the exarrunation, and the effort made to expel the enema. An emergency call button should be available i n the lavatory so that the patient can summon help if needed. Although the patient's privacy must be respected, the radiographer or an aide should frequently inquire to ensure that the patient is al l right.

•

•

Insertion of enema tip

In preparation for i nsertion of the enema tip, the fol lowing teps are observed: I nstruct the patient to tum onto the left side, lean forward about 35 to 40 de­ grees, and rest the flexed right knee on the table, above and in front of the s lightly flexed left knee (Sims' posi­ tion). This position relaxes the abdomi­ nal muscle , which decreases i ntraab­ dominal pressure on the rectum and makes relaxation of the anal sphi ncter less difficult.

•

•

•

•

•

•

•

•

•

Adjust the IV pole so that the enema contents are no higher than 24 inches (6 1 cm) above the level of the anus. Adjust the overlapping back of the gown or other draping to expose the anal region only, but keep the patient otherwi e wel l covered. The anal ori­ fice is commonly partially obscured by distended hemorrhoids or a fringe of undistended hemorrhoids. Sometimes there is a contraction or other abnor­ mal ity of the orifice. It is therefore nec­ essary for the anus to be exposed and sufficiently well lighted for the orifice to be clearly visible so that the enema tip can be i nserted without injury or discomfort. Run a little of the bari um mixture into a waste basin to free the tubing of air, and then lubricate the rectal tube well with a water-sol uble l ubricant. Advise the patient to relax and take deep breaths so that no discomfort is felt when the tube i s inserted. Push the right buttock laterally to open the gl uteal fold. As the abdominal muscles and anal sphincter are relaxed during the expira­ tion phase of a deep breath, i nsert the rectal tube gently and slowly into the anal orifice. Fol lowing the angle of the anal canal, direct the tube anteriorly I to I Y; inches (2.5 to 3.8 cm). Then fol­ lowing the curve of the rectum, direct the tube sl ightly superiorly. I n sert the tube for a total distance of no more than 3 Y; to 4 i nches (8.9 to 1 0 cm). Insertion for a greater distance is not only unnecessary but may i njure the rectum. If the tube does not enter easily, ask the patient to assist if capable. Never forcibly i nsert a rectal tube be­ cause the patient may have di stended internal hemorrhoids or another condi­ tion that makes forced insertion of the tube dangerous. After the enema tip is inserted, hold it in position to prevent it from slipping while the patient turns to the supine or prone position for fluoroscopy, according to the preference of the fluoroscopist. Adjust the protective underpadding, and relieve any pressure on the tubing so that the enema mixture will flow freely.

Fig. 1 7-77 Double-contrast AP colon.

1 67

SINGLE-CONTRAST BARIUM E N EMA Administration of contrast medium

After prepari ng the patient for the exami­ nation, the radiographer observes the fol­ lowing step : Notify the radiologist as soon as every­ thing is ready for the examination. If the patient has not been introduced to the radiologist, make the i ntroduction at this time. At the radiologist's request, release the control clip and ensure the enema flow. When occlusion of the enema tip oc­ curs, displace soft fecal material by withdrawi ng the rectal tube about 1 i nch (2.5 cm). Then before reinserting the tip, temporari ly elevate the enema bag to i ncrease fluid pressure. •

•

•

The rectal ampulla fills slowly. Unless the barium flow is stopped for a few sec­ onds once the rectal ampulla is full, the suspension will flow through the sigmoid and descending portions of the colon at a fairly rapid rate, frequently causing a se­ vere cramp and acute stimulation of the defecation i mpUlse. The flow of the bar­ ium suspension is usually stopped for sev­ eral seconds at frequent i ntervals during the fluoroscopically controlled filli ng of the colon.

During the fluoroscopic procedure, the radiologist rotates the patient to i nspect all segments of the bowel. The radiologist takes spot radiographs as i ndicated and determi nes the positions to be used for subsequent radiographic studies. On com­ pletion of the fl uoroscopic exami nation, the enema tip is usually removed so that the patient can be maneuvered more eas­ ily and so that the tip is not accidental ly displaced during the i maging procedure. A retention tube is not removed until the patient is placed on a bedpan or the toilet.

•

Left colic flexure

Right colic flexure

Transverse colon

Descending colon Ascending colon

Terminal ileum Cecum

Sigmoid

Air-filled retention tip Fig. 1 7-78 Single-contrast barium enema image. Sthenic habitus.

1 68

After the I Rs have been exposed (Fig. 1 7-78), the patient is escorted to a toilet or placed on a bedpan and i nstructed to expel as much of the barium suspension as pos­ sible. A postevacuation radiograph is then taken ( Fig. 1 7-79). If this radiograph shows evacuation to be i nadequate for sat­ isfactory delineation of the mucosa, the patient may be given a hot beverage (tea or coffee) to stimulate further evacuation.

Positioning of opacified colon

The most commonly obtained projections for the single-contrast barium enema are the PA or AP, PA obliques, an axial for the sigmoid, and a lateral for demonstration of the rectum.

Fig. 1 7-79 Postevacuation image demonstrating mucosal pattern (arrows). Hyposthenic habitus.

1 69

DOUBLE -CONTRAST BARIUM ENEMA Two approaches to administering double­ contrast barium enemas are currently i n use. The first technique i s a two-stage pro­ cedure, described by Wel i n , l in which the entire colon is fi l led with a barium sus­ pension. After the enema administration, the patient evacuates the barium and i m­ mediately returns to the fluoroscopic table where air or another gaseous medium is injected i nto the colon. The second ap­ proach is the singLe-stage doubLe-contrast examination. The popularity of this ap­ proach can be attributed primarily to re­ cent advancements in the manufacture of high-density bari um sulfate. Single-stage procedure

In performing the single-stage double­ contrast enema, certain requirements must be met to ensure an adequate examination. The most important requirement is that the patient's colon be exceptionally clean. Residual fecal material can obscure small 'Welin S : Modern trends in diagnostic roentenology of the colon, Br J Radial 3 1 :453, 1 958.

polyps or tumor masses. A second re­ quirement is that a suitable barium sus­ pension be u ed. A barium mixture that c lumps or flakes w i l l neither c learl y demonstrate the l u men nor properly drain from the colon. Currently avai lable premixed liquid barium products are general ly more uni­ form for radiographic use than most bar­ ium suspensions mixed in the health care institution. A barium product with a den­ sity as high as 200% weight/volume may be used for a si ngle-stage double-contrast examination of the colon. The most im­ portant criterion is that the barium flows sufficiently to coat the wall s of the colon. With advances in the manufacture of high-density batium, high-quality double­ contrast colon radiographs can be consis­ tently obtained during one filli ng of the colon. In the single-stage procedure the bar­ ium and air are instil led in a single proce­ dure. Miller! described a 7-pump method for performing single-stage double-contrast examinations. This method reduces cost, ' Mi ller RE: Barium pneumocolon : technologist-per­ formed "7-pump" method, Am J Roentgenol 1 39: 1 230, 1 982.

Fig. 17 -80 AP oblique colon, RPO position, double-contrast study.

1 70

saves time, and reduces radiation exposure to the patient. (A more complete descrip­ tion of the 7-pump method i provided in the seventh edition or earlier editions of this atlas.) Fl uoroscopy is performed to check the location of the barium, and additional air is i nstilled under fluoroscopic control. The patient is slowly rotated 360 degrees and placed in the supine po ition. Then spot radiographs and overhead radiographs are taken ( Figs. 1 7-80 and 1 7-8 1 ). In addition to the 7-pump method, a single-stage double-contrast examination can be performed using a teChnique that does not employ a special air-contrast en­ ema tip. With this technique the barium and air are insti l led through the closed en­ ema bag system (Fig. 1 7-82).

Fig. 1 7-81 AP colon, right lateral decubitus position.

Filling colon with barium

A.

Insertion of enema tip creates closed system.

B. Barium is instilled

in colon.

Flow rate controlled by: Degree of elevation of bag Gentle manual pressure on bag Pressure cuff (when thicker mixture is preferred) Incorporated filter that prevents passage of clumps into tubing.

C. Passive. controlled evacuation

is effected by lowering bag.

Patient does not leave table. Enema tip is not removed.

D. Amount of barium Is adjusted.

Amount of barium in colon adjusted by: Siphoning of excess in retrograde manner Lowering bag. which enables bulk of enema to be withdrawn with im­ mediate relief of distention and cramps and prevention of spillage.

F. Double-contrast study is started

immediately by simply Inverting bag.

Reintroduction of material as indicated by condition of patient.

Carban dioxide or air Is Introduced into colon by applying gentle pressure. Amount and rate of flow are controlled by fluoroscopic observation.

Examination Is complete. Closed system has not been broken. Entire examination has been performed in single stage. Fig. 1 7-82 Conduction of single-stage. closed-system. double-contrast examination. (From Pochaczevsky R, Sherman RS: A new technique for roentgenologic examination of the colon, AJR 89:787. 1 963.)

1 71

Welin method

Stage one

Welinl•2 developed a technique for double­ contrast enemas that reveals even the smallest intraluminal lesions (Figs. 1 7-83

With the patient in the prone position to prevent possible ileal leak, the colon is filled to the left colic flexure, after which a conventional radiograph is taken (i.e., a right lateral projection of the barium-filled rectum). The patient is then sent to the lavatory to evacuate the barium. Afterward, if the patient feel the need to do so, he or

and 1 7-84). He stated that this method of examination is extremely valuable in the early diagnosis of conditions such as ulcer­ ative colitis, regional colitis, and polyps. Welin stressed the importance of prepar­ ing the intestine for the examination, stat­ ing that ( I ) the colon must be cleansed as thoroughly as possible and (2) the colonic mucosa must be prepared in such a way that an extremely thin and even coating of barium can adhere to the colonic wall . He recommended regulation of evacuation so that the two stages of the examjnation can be carried out at short intervals to avoid un­ necessary wruting time and the patient does not have to be in the examinjng room more than 20 to 25 minutes.

she is al lowed to lie down and rest.

Stage two When the patient returns to the examining table, the enema tip is inserted and the pa­ tient is again turned to the prone position. The prone position not only prevents ileal leakage with resultant opacification and

The radiologist al lows the barium mix­ ture to run up to the middle of the sigmoid colon (sl ightly farther if the sigmoid is long). The patient is then turned onto the right side, and air is instilled through the enema tip. The air forces the barium along, distributing it throughout the colon, and the patient i s turned as required for even coating of the entire colon. Spot ra­ diographs are made as indicated. If bar­ ium flows back into the rectum, it i drained out through the enema tip. More air is then instilled. Welin stressed the im­ portance of instilling enough air ( 1 800 to 2000 ml or more) to obtain proper disten­ tion of the colon.

overlap of the small intestine on the rec­ tosigmoid area, but it also aids in adequate drainage of excess barium from the rectum.

'Welin S : Modern trends in diagnostic roentgenol­ ogy of the colon, Br 1 Radiol 3 1 :453, 1 958. 2Welin S : Results of the Malmo technique of colon examination, lAMA 1 99:369, 1 967.

Fig. 1 7-83 Upright oblique position of flexure, following imple­ mentation of Welin method.

1 72

Fig. 1 7-84 Upright PA colon following implementation of Welin method.

When sufficient distention of the colon has been obtained, 35343 cm ( 1 43 1 7 inch) radiographs are obtained (Figs. 1 7-85 to 1 7-87) to i nclude the rectum, using the fol lowing sequence: a PA projection, PA oblique (LAO and RAO) projections, and a right lateral projection (24330 cm [ 1 03 1 2 i nches]) . The patient is then turned to the supine position for an AP projection and two AP oblique (LPO and RPO) pro­ jections, all to include the transverse colon and its flexures. These studies are fol lowed by AP projections in the right and left lateral decubitus positions to in­ c lude the rectum. Finall y, the patient is placed in the erect position for PA and PA oblique ( RAO and LAO) projections of the horizontal colon and the left and right colic flexures.

Fig. 1 7-85 Pedunculated polyps (arrows) during stage 2 of Welin method.

Fig. 1 7-86 Small carcinoma with intubation (arrow) during stage 2 of Welin method.

Fig. 1 7-87 Cobblestone appearance of granulomatous colitis in an image obtained during stage 2 of Welin method.

1 73

Large I ntestine

OPACIFIED COLON Radiographic studies of the adult colon are made on 35 X 43 cm I Rs. Except for axial projections, these I Rs may be centered at the level of the iliac crests on patients of sthenic build-somewhat higher for hyper­ sthenic patients and somewhat lower for as­ thenic patients. The AP and PA projections of the colon and abdomen may require two exposures, with the I Rs placed crosswise: the first is centered high enough to include the diaphragm and the second low enough to include the rectum. Localized studies of the rectum and rectosigmoid junction are often exposed on 24 X 30 cm or 30 X 35 cm IRs centered at or sl ightly above the level of the pubic symphysis. Preevacuation radiographs of the colon include one or more images for the demonstration of oth­ erwise obscured flexed and curved areas of the large intestine. Depending on the preference of the ra­ diologist, the radiographic projections taken after fluoroscopy vary considerably. Therefore any combination of the follow­ ing images may be taken to complete the examination.

'" PA PROJECTION

Central ray •

Image receptor: 35

X 43 cm

lengthwise Position of patient •

Structures shown

Place the patient in the prone position.

Position of part • •

•

• •

Perpendicular to the I R to enter the midline of the body at the level of the i liac crests

Center the midsagittal plane to the grid. Adjust the center of the IR at the level of the il iac crests (Fig. 1 7-88). In addition to positioning for the PA projection, place the fluoroscopic table in a slight Trendelenburg position if needed. This table position helps sepa­ rate redundant and overlapping loops of the bowel by "spi l l i ng" them out of the pelvis. Shield gonads. Respiration: Suspend.

The PA projection demonstrates the entire colon with the patient prone ( Figs. 1 7-89 to 1 7-9 1 ). EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Entire colon, including the flexures and the rectum. (Two I Rs may be needed for hypersthenic patients.) • Vertebral column centered so that the ascending and descending portions of the colon are i nc luded.

Fig. 1 7-88 PA large intestine.

1 74

Large I ntestine

Fig. 1 7-89 Single-contrast PA large intestine.

Left colic flexure Descending colon

Transverse colon Right colic flexure

Ascending colon

Sigmoid Rectum

Fig. 1 7 -90 Double-contrast PA large intestine: hyposthenic body habitus.

Fig. 1 7-91 Postevacuation PA large intestine.

1 75

Large Intestine

'"

PA AXIAL PROJECTION

•

Image receptor: 3 5 x 43 cm lengthwise or 24 X 30 cm lengthwise Position of patient •

•

• •

Directed 30 to 40 degrees caudad to en­ ter the midline of the body at the level of the anterior superior iliac spines (ASISs)

The following should be clearly demon­ strated: • Rectosigmoid area centered to radi­ ograph • Rectosigmoid area with less superimpo­ sition than in the PA projection because of the angulation of the central ray • Transverse colon and both flexures not necessaril y i nc luded

Structures shown

Place the patient in the prone position.

Position of part •

EVALUATION CRITERIA

Central ray

The PA axial projection best demonstrates the rectosigmoid area of the colon (Figs. 1 7-93 and 1 7-94).

Center the midsagittal plane to the grid. Adjust the center of the IR at the level of the i liac crests (Fig. 1 7-92). ShieLd gonads. Respiration: S uspend.

-

---

------ _.

_.

. ____

1

_ __ _ _

"

�

.

.,...

,,"<..':oJ 1

..".

,

Fig. 1 7-92 PA axial large intestine.

Left colic ftexure Transverse colon

Sigmoid

Rectum

Fig. 1 7-93 Single-contrast PA axial (3D-degree an­ gulation) large intestine.

1 76

Fig. 1 7-94 Double-contrast PA axial (4D-degree angulation) large intestine.

Large I ntestine

.. PA OBLIQUE PROJECTION RAO position Image receptor: 35

x 43 cm

lengthwise

EVALUATION CRITERIA

Central ray

Perpendicular to the IR and entering approxi mately 1 to 2 i nches (2.5 to 5 cm) lateral to the midli ne of the body on the elevated side at the level of the i l iac crest

Position of patient •

Place the patient in the prone position.

Position of part •

•

•

•

• •

With the patient's right arm by the side of the body and the left hand by the head, have the patient roll onto the right hip to obtain a 35- to 45-degree rotation from the radiographic table. Flex the patient's left knee to provide stability. Center the patient's body to the midli ne of the grid. Adj ust the center of the IR at the level of the i l iac crests (Fig. 1 7-95 ) . Shield gonads. Respiration: Suspend.

Structures shown

The RAO position best demonstrates the right colic flexure, the ascendi ng portion of the colon, and the sigmoid portion of the colon (Figs. 1 7-96 and 1 7-97) .

The fol lowing should be clearly demon­ strated: • Entire colon • Right colic flexure less superimposed or open when compared with the PA projection • Ascending colon, cecum, and sigmoid colon

Fig. 1 7-95 PA oblique large intestine, RAO position.

Left colic flexure

Right colic flexure Descending colon

Ascending colon

Sigmoid

Fig. 1 7-96 Single-contrast PA oblique large intestine, RAO position.

Fig. 1 7-97 Double-contrast PA oblique large intestine, RAO position.

1 77

Large I ntestine

..

PA OBLIQUE PROJECTION

Structures shown

LAO position

The LAO position best demonstrates the left colic flexure and the descending por­ tion of the colon ( Figs. 1 7-99 and 1 7- 1 00).

Image receptor:

35

x

43 cm

EVALUATION CRITERIA

lengthwise Position of patient •

Place the patient in the prone position.

The fol lowi ng should be c learly demon­ strated: • Entire colon • Left colic flexure less superimposed or open when compared with the PA pro­ jection • Descending colon

Position of part •

•

•

•

• •

With the patient's left arm by the side of the body and the right hand by the head, have the patient roll onto the left hip to obtain a 35- to 45-degree rotation from the radiographic table. Flex the patient's right knee to provide stability. Center the patient's body to the midl ine of the grid. Adjust the center of the l R at the level of the il iac crest (Fig. 1 7-98). Shield gonads. Respiration: Suspend.

Central ray

Perpendicular to the I R and entering approxi mately 1 to 2 inches (2.5 to 5 cm) lateral to the midl ine of the body on the elevated side at the level of the il iac crest

Fig. 1 7-98 PA oblique large intestine, LAO position.

Left colic ftexure Right colic ftexure Transverse colon

Descending colon Ascending colon

Vermiform appendix Sigmoid

Fig. 1 7-99 Single-contrast PA oblique large intestine, LAO position.

1 78

Fig. 1 7- 1 00 Double-contrast PA oblique large intestine, LAO pOSition.

Large I ntestine

.. LATERAL PROJECTION R or L position Image

receptor: 24

•

X

Perpendicular to the I R to enter the mid­ coronal plane at the level of the ASIS

30 cm Structures shown

lengthwise Position of patient •

EVALUATION CRITERIA

Central ray

Place the patient in the lateral recum­ bent position on either the left or right side.

The lateral projection best demonstrates the rectum and distal sigmoid portion of the colon (Figs. 1 7- 1 02 and 1 7- 1 03).

The following should be clearly demon­ strated: • Rectosigmoid area in the center of the radiograph • No rotation of the patient • Superimposed hips and femurs • SupeJior portion of colon not necessar­ ily i ncluded when the rectosigmoid re­ gion is the area of i nterest

Position of part •

•

•

• • •

Center the midcoronal plane to the cen­ ter of the grid. Flex the patient's knees slightly for sta­ bility, and place a support between the knees to keep the pelvis lateral. Adj ust the patient's shoulders and hips to be perpendicular ( Fig. 1 7- 1 0 1 ). Adj ust the center of the IR to the ASIS. Shield gonads. Respiration: Suspend.

Fig. 1 7- 1 0 1 Left lateral rectum.

Sigmoid Sacrum Rectum Pubic symphysis

Fig. 1 7 - 1 02 Single-contrast left lateral rectum.

Fig. 1 7- 1 03 Double-contrast left lateral rectum.

1 79

Large I ntestine

,. AP PROJECTION

•

I mage receptor: 35

x 43 cm

lengthwise Position of patient •

Place the patient in the supine position.

Position of part • •

• •

EVALUATION CRITERIA

Central ray

Perpendicular to the IR to enter the midline of the body at the level of the i liac crests

Structures shown

The AP projection demonstrates the entire colon with the patient supine (Figs. 1 7- 1 05 and 1 7- 1 06).

The following should be clearly demon­ strated: • Entire colon, including the splenic flex­ ure and the rectum. (Two IRs may be needed for hypersthenic patients.) • Vertebral column centered so that the ascending colon and the descending colon are completely included.

Center the midsagittal plane to the grid. Adjust the center of the IR at the level of the il iac crests (Fig. 1 7- 1 04). Shield gonads. Respiration: Suspend.

Fig. 1 7- 1 04 AP large intestine.

Left colic flexure

Transverse colon Right colic flexure

Descending colon Ascending colon

Sigmoid

Fig. 1 7- 1 05 Single-contrast AP large intestine. Sthenic habitus.

1 80

Fig. 1 7 - 1 06 Double-contrast AP large intestine. Asthenic habitus.

Large I ntestine

'" AP AXIAL PROJECTION Image receptor: 35 x 43 cm or 24 X 30 cm lengthwise Position of patient •

EVALUATION CRITERIA

Structures shown

The AP axial projection best demonstrates the rectosigmoid area of the colon (Figs. 1 7- 1 08 and 1 7- 1 09). A simi lar i mage is obtained when the patient i s prone (see Fig. 1 7-92) .

Place the patient in the supine position.

Position of part • •

• •

Center the midsagittal plane to the grid. Adj ust the center of the IR at a level ap­ proximately 2 i nches (5 cm) above the level of the i l iac crests (Fig. 1 7- 1 07). Shield gonads. Respiration: S uspend.

The fol lowi ng should be clearly demon­ strated: • Rectosigmoid area centered when using a 24 X 30 cm I R • Rectosigmoid area with less superimpo­ sition than in the AP projection because of the angulation of the central ray • Transverse colon and flexures not nec­ essaril y included

Central ray •

•

Directed 30 to 40 degrees cephalad to enter the midli ne of the body approxi­ mately 2 i nches (5 cm) below the level of the ASISs Directed to enter the inferior margin of the pubic symphysis when a coll imated image is desired for demonstration of the rectosigmoid region

Fig. 1 7- 1 07 AP axial large intestine,

Descending colon

Sigmoid

Rectum

Fig. 1 7 - 1 08 Single-contrast AP axial large intestine,

Fig. 1 7- 1 09 Double-contrast AP axial large intestine.

181

Large I ntestine

..

AP OBLIQUE PROJECTION LPO position

Image receptor: 35

•

x 43 cm

lengthwise Position of patient

Place the patient in the supine position.

•

Position of part •

•

•

•

• •

With the patient's left arm by the side of the body and the right arm across the superior chest, have the patient roll onto the left hip to obtain a 35- to 45degree rotation from the table. Use a positioning sponge and flex the patient's right knee for stability, if needed. Center the patient's body to the midli ne of the grid. Adjust the center of the IR at the level of the iliac crests (Fig. 1 7- 1 1 0). Shield gonads. Respiration: Suspend.

EVALUATION CRITERIA

Central ray

Perpendicular to the I R to enter approx­ i mately I to 2 i nches (2.5 to 5 cm) lat­ eral to the midli ne of the body on the el­ evated side at the level of the iliac crest

Structures shown

The LPO position best demonstrates the right colic flexure and the ascending and sigmoid portions of the colon (Figs. 1 7- 1 I I and 1 7- 1 1 2).

The following should be clearly demon­ strated: • Entire colon • Right colic flexure less superimposed or open when compared with the AP projection • Ascending colon, cecum, and sigmoid colon

Fig. 1 7- 1 1 0 AP oblique large intestine, LPO position.

Left colic flexure

Right colic flexure Descending colon Ascending colon

Sigmoid Rectum

Fig. 1 7- 1 1 1 Single-contrast AP oblique large intestine, LPO position.

1 82

Fig. 1 7 - 1 1 2 Double-contrast AP oblique large intestine, LPO position.

Large Intestine

'" AP OBLIQUE PROJECTION RPO position Image receptor:

35

x

43 cm

EVALUATION CRITERIA

Structures shown

The RPO position best demonstrates the left colic flexure and the descending colon ( Figs. 1 7- 1 1 4 and 1 7- 1 1 5).

lengthwise

The fol lowing should be clearly demon­ strated: • Entire colon • Left col ic flex ure and descending colon

Position of patient •

Place the patient in the supine position.

Position of part •

•

•

•

• •

With the patient's right arm by the side of the body and the left arm across the superior chest, have the patient roll onto the right hip to obtain a 35- to 45-degree rotation from the radiographic table. Use a positioning sponge and flex the patient's right knee for stab i lity, i f needed. Center the patient's body to the midl ine of the grid. Adj ust the center of the I R at the level of the i liac crests (Fig. 1 7- 1 1 3) . Shield gonads. Respiration: Suspend.

Central ray •

Perpendicular to the I R to enter approx­ imately 1 to 2 inches (2.5 to 5 cm) lat­ eral to the midli ne of the body on the el­ evated side at the level of the i l iac crest Fig. 1 7- 1 1 3 AP oblique large intestine, RPO position.

Left colic flexure

Transverse colon Right colic flexure

Descending colon Ascending colon

Sigmoid

Rectum Fig. 1 7- 1 1 4 Single-contrast AP oblique large intestine, RPO position.

Fig. 1 7- 1 1 5 Double-contrast AP oblique large intestine, RPO position.

1 83

large I ntestine

Decubitus Positions When a patient is being prepared for an ex­ amination in a decubitus position, the fol­ lowing general guidelines are observed: Take all decubitus radiographs ( 1 ) with the patient lying on the fluoroscopic table and a grid IR firmly supported be­ hind the patient's body, (2) with the pa­ tient lying on a patient cart with the body against an upright table or chest device, or (3) with the patient lying on a table or cart and a specially designed vertical grid device behind the patient. To ensure demonstration of the side on which the patient is lying, elevate the patient on a suitable radiolucent sup­ port. If this is not done, the radiograph will record artifacts from the patient mattress or the table edge and superim­ pose these i mages over the portion of the patient's colon on the "down" side. For all decubitus procedures, exercise extreme caution to ensure that the wheels of the cart are securely locked so that the patient will not fall .

•

•

•

•

1 84

•

For lateral decubitus radiographs, have the patient put the back or abdomen against the vertical grid device. Most patients find it more comfortable to have their back against the vertical grid device than to have their abdomen against the same device. If both lateral decubitus radiographs are requested (which i s often the case w ith air-contrast examinations), take one ra­ diograph with the patient's anterior body surface against the vertical grid device and the second radiograph with the posterior body surface against the vertical grid device.

Large I ntestine

.. AP OR PA PROJECTION Right lateral decubitus position Image receptor: 35

x 43 cm

lengthwise Position of patient •

•

Place the patient on the right side with the back or abdomen i n contact with the vertical grid device. Exercise care to ensure that the patient does not fal l from the cart of table; if a cart is u ed, lock aLL wheels securely i n p o ition.

Position of part •

•

• •

With the patient lying on an elevated ra­ diol ucent support, center the midsagit­ tal plane to the grid. Adjust the center of the IR to the level of the il iac crests ( Fig. 1 7- 1 1 6). Shield gonads. Respiration: Suspend.

Fig. 1 7- 1 1 6 AP large intestine, right lateral decubitus position.

Central ray •

Horizontal and perpendicular to the I R to enter the midline of the body at the level of the i l iac crests

Structures shown

The right lateral decubitus position demon­ strate an AP or PA projection of the con­ trast-fi l led colon . This position best demonstrates the "up" medial side of the ascendjng colon and the lateral side of the descending colon when the colon is in­ flated with air (Figs. 1 7- 1 1 7 and 1 7- 1 1 8). Fig. 1 7- 1 1 7 Double-contrast AP large intestine, right lateral decubitus position.

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Area from the left colic flexure to the rectum. • No rotation of the patient, as evidenced by the ribs and pelvis. • For single-contrast examinations, ade­ quate penetratjon of the barium; for double-contrast examjnations, the air­ i nflated portion of the colon is of pri­ mary importance and should not be overpenetrated.

Left colle ftexure Sigmoid

Transverse colon r--'!!!�-"-c---��

Right colle ftexure

Fig. 1 7- 1 1 8 Double-contrast AP large intestine, right lateral decubitus position.

1 85

Large Intestine

'" PA OR AP PROJECTION Left lateral decubitus position

Image receptor:

35

x 43 cm

lengthwise Position of patient •

•

Place the patient on the left side with the abdomen or back in contact with the vertical grid device. Exercise care to ensure that the patient does not fal l from the cart of table; if a cart is used, lock all wheels securely in position.

Position of part •

•

• •

With the patient lying on an e levated ra­ diolucent support, center the midsagit­ tal plane to the grid. Adj ust the center of the IR at the level of the i liac crests (Fig. 1 7- 1 1 9). Shield gonads. Respiration: Suspend.

Fig. 1 7 - 1 1 9 PA large intestine, left lateral decubitus position.

Right colic flexure Ascending colon

Central ray •

Horizontal and perpendicular to the I R t o enter the midl ine of the body at the level of the i l iac crests

Rectum

Sigmoid

Structures shown

The left lateral decubitus position demon­ strates a PA or AP projection of the con­ trast-fi l led colon. This position best demonstrates the "up" lateral side of the ascending colon and the medial side of the descending colon when the colon is i n­ flated with air ( Figs. 1 7- 1 20 and 1 7- 1 2 1 ).

==�-+- Descending colon Left colic flexure Fig. 1 7 - 1 20 Double-contrast PA large intestine, left lateral decubitus position.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ stJ'ated: • Area from the left colic flexure to the rectum. • No rotation of the patient, as evidenced by the ribs and pelvis. • For single-contrast examinations, ade­ quate penetration of the barium; for double-contrast examinations, the air­ inflated portion of the colon is of pri­ mary i mportance and should not be overpenetrated.

Fig. 1 7- 1 2 1 Double-contrast PA large intestine, left lateral decubitus position.

1 86

Large Intestine

LATERAL PROJECTION R or L ventral decubitus position Image receptor: 35 x 43 em length­

Central ray •

Horizontal and perpendicular to the I R t o enter the midcoronal plane o f the body at the level of the iliac crests

wise Structures shown Position of patient •

Place the patient in the prone position with either the right or left side against the vertical grid device.

Position of part •

•

• •

The ventral decubitus position demon­ strates a lateral projection of the contrast­ filled colon. This position best demon­ strates the "up" posterior portions of the colon and is most valuable in double-con­ trast examinations (Fig. 1 7- 1 22).

Elevate the patient on a radiolucent support, and center the midcoronal plane to the grid. Adjust the center of the IR at the level of the iliac crests. Shield gonads. Respiration: Suspend.

EVALUATION CRITERIA

The fol lowing should be c learly demon­ strated: • Area from the flexures to the rectum. • No rotation of the patient. • For single-contrast examinations, ade­ quate penetration of the barium; for double-contrast examinations, the air­ inflated portion of the colon is of pri­ mary i mportance and should not be overpenetrated. • Enema tip removed for an unobstructed image of the rectum.

A

Left colic ftexure Rectum Descending colon !!:;.--:----::::--'---:::-'-....".� Sigmoid �---­

B

Right colic ftexure �---'----:= Transverse colon r-------''___=' Transverse colon Ascending colon

Fig. 1 7 - 1 22 A, Patient in position for a lateral projection, ventral decubitus position. B, Left lateral large intestine, ventral decubitus position.

1 87

large Intestine

'" Ap, PA, OBLIQUE, AND LATE RAL PROJECTIONS Upright position

Left colic ftexure

Upright AP, PA, oblique, and lateral pro­ jections may be taken as requested. The po­ sitionjng and evaluation criteria for upright radjographs are identical to those required for the recumbent positions. However, the IR is placed at a lower level to compensate for the drop of the bowel because of the ef­ fect of gravity (Figs. 1 7- 1 23 to 1 7- 1 25).

Right colic ftexure

Transverse colon

-;-_--:--":-_ ..." .:.. _....,--Descending colon !--___--'c..:.'--

Cecum Sigmoid Rectum ��=:--:-;-.....,...,.;

Fig. 1 7 - 1 23 Upright double-contrast AP large intestine.

Fig. 1 7- 1 24 Upright double-contrast PA large intestine. 1 88

Fig. 1 7 - 1 25 Upright double-contrast AP oblique large intestine, RPO position.

Large I ntestine

AXIAL PROJECTION

I nstruct the patient to abduct the thighs as far as the edge of the table permits so that they do not i nterfere with flexion of the body. Center the I R to the midline of the pel vis, and ask the patient to lean di­ rectly forward as far as possible (Fig. 1 7- 1 26). Have the patient grasp the ankles for support. Respiration.: Suspend. The exposure required for this projec­ tion is approximately the same as that re­ quired for a lateral projection of the pelvis.

•

CHASSARD-LAPIN E METHOD The Chassard-Lapi ne method is used to demonstrate the rectum, rectosigmoid junction, and sigmoid. This projection, which is made at almost a right angle to the AP projection, demonstrates the ante­ rior and posterior surfaces of the lower portion of the bowel and permits the coil s o f the sigmoid t o b e projected free from overlapping. ' ·3 The projection may be ex­ posed after evacuation of the large i ntes­ tine, although a preevacuation radiograph can be exposed when the patient has rea­ sonable sphi ncteric control . ' Image receptor: 3 0 x 3 5 c m length­

Structures shown

The Chassard-Lapine image demonstrates the rectum, rectosigmoid junction, and sig­ moid in the axial projection (Fig. 1 7- 1 27).

•

•

•

Central ray

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Rectosigmoid area in the center of the radiograph • Rectosigmoid area not obscured by su­ perior area of colon • M i n i mal superimposition of the rec­ tosigmoid area • Penetration of the lumbosacral region and the barium

Perpendicular through the lumbosacral region at the level of the greater trochanters

wise Position of patient

Seat the patient on the radiographic table. Position of part •

•

I nstruct the patient to sit well back on the side of the table so that the mid­ coronal plane of the body is as close as possible to the midline of the table. If necessary, shift the transversely placed 30 X 35 cm ( I I X 1 4 inch) IR forward in the Bucky tray so that its transverse axis coincides as nearly as possible with the midcoronal plane of the body.

' Raap G: A position of value in studying the pelvis and its contents, South Med J 44:95, 1 95 1 . 'Cimmino CV: Radiography of the sigmoid flexure with the Chassard-Lapine projection, Med Radiogr Photogr 30:44, 1 954. 'Ettinger A, Elkin M: Study of the sigmoid by spe­ cial roentgenographic views, Am J Roelllgenoi 72: 1 99, 1 954.

Femur

Greater trochanter Sigmoid

Ischial tuberosity Rectum

C.R.

Fig. 1 7- 1 26 Chassard-Lapine method.

Fig. 1 7- 1 27 Axial rectosigmoid: Chassard-Lapine method.

1 89

Large Intestine

COLOSTOMY STUDIES Enterostomy (Gr. enteron, intestine + stom£/., opening) is the general term ap­ plied to the surgical procedure of formi ng an artificial opening to the intestine, usu­ ally through the abdominal wall, for fecal passage. The regional term are coLostomy, cecostomy, iLeostomy, and jejunostomy. The colon is the most common site of disease in the large i ntestine. Therefore surgical procedures are often performed on this structure. Loop colostomy is some­ times performed to divert the fecal col­ umn, either temporarily or permanently, from areas of diverticulitis or ulcerative colitis. Most colostomies, however, are performed because of malignancies of the lower bowel and rectum. When a tumor is present, the lower carcinomatous part of the bowel is resected, and the end of the re­ maining part of the bowel is brought to the surface through the abdominal wal l . This passage, or stoma, has no sphi ncter.

A device must be used to prevent spillage of contrast enema material in the patient with a colostomy. Otherwise, be­ cause of the absence of sphincter control, the contrast enema may escape through the colostomy almost as rapidly as it is i n­ jected. I f this happens, bowel fi l l i ng will be unsatisfactory and shadows cast by barium soil age of the abdominal wal l and the examining table will obscure areas of interest. Abdominal stomas must be effec­ tively occluded for studies made by retro­ grade i njection, and leakage around the stomal catheter must be prevented for studies made by i njection into either an abdominal or a perineal colostomy. Numerous devices are available for this purpose.

DIAGNOSTIC ENEMA Diagnostic enemas may be given through a colostomy stoma with the use of tips and adhesive disks designed for the patient's use in irrigating the colostomy (Fig. 1 7- 1 28). Preparation of intestinal tract The tips are available in four sizes to ac­ Postoperative contrast enema studies are commodate the usual sizes of colostomy performed at suitable intervals to deter­ stomas. These tips usually have a flange to mine the efficacy of treatment in the pa­ prevent them from slipping through the tient with diverticulitis or ulcerative coli­ colostomy opening. An adhesive disk is tis and to detect new or recurrent lesions placed over the flange to minimize reflux in the patient who has had a tumor. The soilage. The enema tubing is attached di­ demonstration of polyps and other intralu­ rectly to the tip, which the patient holds in minal lesions depends on adequate cleans­ position to prevent the weight of the tubing i ng of the bowel, which is as important in from displacing the tip to an angled posi­ the presence of a colostomy as otherwise. tion. I n addition to keeping a set of Laird In the patient with a colostomy, the usual tips on hand, it is recommended that the pa­ preparation is i rrigation of the stoma the tient be asked to bring an irrigation device. n ight before the study and again on the Retention catheters are also used i n morning of the examination. colostomy studies. Some radiologists use them alone, and others insert them Colostomy enema equipment through a device to prevent sl ipping and Although equipment must be scrupulously to collect leakage. Colostomy stomas are clean and nondisposable items must be fragile and thus are subject to perforation steri l ized after each use, sterile technique by any u ndue pressure or trauma. is not required because the stoma is part of Perforations have occurred during the i n­ the intestinal tract. Except for a suitable sertion of an inflated bulb into a blind device to prevent stomal leakage of the pouch and from overdistention of the contrast material, the equipment used i n stoma. the patient with a colostomy is the same as that used in routine contrast enema stud­ Preparation of patient ies. The same bari um sulfate formula is If the patient uses a special dressing, used, and gas studies are made. The colostomy pouch, or stomal seal, he or she opaque and double-contrast studies can be should be advised to bring a change for performed i n a single-stage examination use after the exami nation. When fecal with the use of a disposable enema kit. emission is such that a pouch is required, the patient should be given a suitable dressing to place over the stoma after the device has been removed.

The radiographer then observes the fol­ lowing steps: Clothe the patient in a kimono type of gown that opens in front or back, de­ pending on the location of the colostomy. Place the patient on the exami ni ng table in the supine position if he or she has an abdominal colostomy and in the prone position if he or she has a perineal colostomy. Before taking the preliminary radiograph and while wearing disposable gloves, re­ move and discard any dressing. Cleanse the skin around the stoma ap­ propriately. Place a gauze dressing over the stoma to absorb any seepage unti l the physi­ cian is ready to start the exami nation. Lubricate the stomal catheter or tube well (but not excessively) with a water­ soluble lubricant. The catheter should be inserted by the physician or the pa­ tient. If a catheter is forced through a stoma, the colon may be perforated. Spot radiograph are taken during the exami nation. Postfluoroscopy radiographs are taken as needed. The projections re­ quested depend on the location of the stoma and the anatomy to be demon­ strated ( Figs. 1 7- 1 29 to 1 7- 1 32). •

•

•

•

•

•

� � @ � ��� ==

Stamaseal

ADH E S I V E D I S C

•-

-

-

_

=

'

_

- -

'

-;. :. I�' � � I I I ...l : I _

- - _ .....

_ _ _ _ _ _ _

Dry skin thoroughlv before applymg. medlcol Products Division

...J

::un.

... � l " ... . . . ... ... � . .......... " ... . . . .

Fig. 1 7 - 1 28 Laird colostomy irrigation tips and Stomaseal disks,

1 90

Large Intestine

Fig. 1 7 - 1 29 Opaque colon by way o f perineal colostomy.

Fig. 1 7- 1 30 Opaque colon by way of abdominal colostomy.

Left colic ftexure Right colic ftexure

Transverse colon

Enema tubing Stomaseal ftange !!!!�-"l5:J!!

Fig. 1 7- 1 3 1 Double-contrast colon in patient with ab­ dominal colostomy.

Fig. 1 7- 1 32 Double-contrast AP oblique colon by way of abdominal colostomy.

191

Large I ntestine

DEFECOGRAPHY Defecography, evacuation proctography, or dynamic rectal examination is a rela­ tively new radiologic procedure per­ formed on patients with defecational dys­ function. No preparation of the patient is necessary, and cleansing enemas are not recommended because water remaining in the rectum dilutes the contrast medium. Early investigators! mixed a diluted suspension of barium sulfate, heated it, and added potato starch to form a smooth barium paste that was semisolid and mal­ leable. 2 .3 Barium manufacturers now package prepared barium products (ap­ proximately 1 00% weight/volume barium sulfate paste) with a special i njector mechanism to i nstill the barium directly into the rectum. ' Burhenne HJ: Intestinal evacuation study: a new roentgenologic technique, Radiol Clin (Basel) 33:79, 1 964. 'Mahieu P, Pringot J, Bodart P: Defecography. I . Description o f a new procedure and results i n normal patients, Gastrointest RadioI 9:247, 1 984. 3Mahieu P, Pringot J, Bodart P: Defecography. I I . Contribution t o the diagnosis o f defecation disor­ ders, Gastroilllest RadioI 9:253, 1 984.

After the barium is instilled, the patient usually is seated in the lateral position on a commercially available radiolucent com­ mode in front of a fluoroscopic unit. A spe­ cial commode chair is recommended so that the anorectal junction and the zone of interest on the radiograph is not overex­ posed. Lateral projections are obtained during defecation by spot filming at the ap­ proximate rate of I to 2 frames per second. Video recording of the defecation process may be used, but the special equipment needed to interpret the images is not al­ ways avai lable, and a hard copy of the im­ ages is also not available.! The resulting images are then evaluated (Figs. 1 7- 1 33 and 1 7- 1 34). This evaluation includes mea­ surements of the anorectal angle and the angle between the long axes of the anal canal and rectum. These measurements are then compared with normal values. ' Mahieu PHG: Defecography. In Margulis AR, Burhenne H : A limentary tract radiology, vol ed 4, St Louis, 1 989, Mosby.

I,

A Fig. 1 7- 1 33 Defecography: lateral anus and rectum spot image showing long axis of anal canal (line A-B) and long axis of rectal canal (line B-C) in a patient with an anorectal angle of 1 1 4 de­ grees. Also demonstrated is an anterior rectocele (arrow).

1 92

Fig. 1 7- 1 34 Postevacuation lateral anus and rectum spot image in the same patient as in Fig. 1 7-1 33,

SUM MARY OF PROJ ECTIONS

PROJECTIONS,

Page

216 218 219 220 22 1 226 230 232 234 235 236

Essential

.. .. .. .. .. .. .. .. ..

POSITIONS,

Anatomy

& METHODS

Projection

Position

Urinary system

AP

Urinary system

AP oblique

RPO and LPO

Urinary system

Lateral

R or L

Urinary system

Lateral

Dorsal decubitus

Renal parenchyma

AP

Pelvlcalyceal system & ureters

AP

Urinary bladder

AP axial or PA axial

Urinary bladder

AP oblique

RPO or LPO

Urinary bladder

Lateral

R or L

Male cystourethrography

AP obllque

RPO or LPO

Female cystourethrography

AP

Method

I I

I I ! 1

I

II INJECTION

Icons in the Essential column indicate projections frequently performed in the United States and Canada. Students should be competent In these projections.

�_

U R I N ARY SYSTEM ANATO MY

Urinary System The urinary system i ncludes the two kid­ neys, two ureters, one urinary bladder; and one urethra (Figs. 1 8- 1 and 1 8-2). The functions of the kidneys include re­ moving waste products from the blood, maintaining fluid and electrolyte balance, and ecreting substances that affect blood pressure and other i mportant body func­ tions. The kidneys normally excrete I to 2 L of urine per day. This urine is expelled from the body via the excretory system, as the urinary system is often called. The ex­ cretory system consists of the following: A variable number of urine-draining branches in the kidney called the ca­ Iyce and an expanded portion called the renal pelvis, which together are known as the pelvicalyceal system

•

•

•

Two long tube called ureters, with one ureter extending from the pelvis of each kidney A saclike portion, the urinary bladder; which receives the distal portion of the ureters and serves as a reservoir A third and smaller tubular portion, the urethra, which conveys the urine to the exterior of the body

•

Right suprarenal gland Right kidney ---Jf---"---1I

A

Suprarenal Glands Closely associated with the uri nary system are the two suprarenal, or adrenal, glands. These ductless endocrine glands have no functional relationship with the urinary system but are i ncluded in this chapter be­ cause of their anatomic relationship with the kidneys. Each suprarenal gland con­ sists of a small, flattened body composed of an internal medullary portion and an outer cortical portion. Each gland is en­ closed in a fibrous sheath and is situated in the retroperitoneal tis ue in close contact with the fatty capsule overlying the medial and superior aspects of the upper pole of the kidney. The suprarenal glands furni h two important substances: ( I ) epinephrine, which is secreted by the medulla, and (2) the cortical hormones, which are secreted by the cortex. These glands are subject to malfunction and a number of diseases. They are not usually demonstrated on pre­ limi nary radiographs but are deli neated when computed tomography (CT) is used. The suprarenal circulation may be demon­ strated by selective catheterization of a suprarenal artery or vein in angiographic procedures.

»---.__...,-- Left kidney

Left ureter

Urinary bladder

Right kidney

Right ureter --+....,-..7.'+++.-\1

B

Urinary bladder

Rectum --+\---'�.,,� Prostate --+--\----31it11 Anal canal ----l,;:--.>...:::--=

Fig. 1 8- 1 Anterior aspect of urinary system in relation to surrounding structures. A, Abdominal structures. B, Bony structures.

Fig. 1 8-2 Lateral aspect of male urinary system in relation to surrounding structures.

1 95

Kidneys The kidneys are bean-shaped bodies. The lateral border of each organ is convex, and the medial border is concave. They have slightly convex anterior and posterior sur­ faces, and they are arbitrarily divided into upper and lower poles. The kidneys mea­ sure approximately 4Y2 inches ( 1 l .5 cm) in length, 2 to 3 inches (5 to 7.6 cm) in width, and about I � inches (3 cm) in thickness. The left kidney usually is slightly longer and narrower than the right kidney. The kidneys are situated behind the peritoneum (retroperitoneal) and are in contact with the posterior wall of the ab­ dominal cavity, one kidney lying on each side of and in the same coronal plane with L3. The superior aspect of the kidney l ies more posterior and the inferior aspect (Fig. 1 8-2). Each kidney lies in an oblique plane and is rotated about 30 degrees anteriorly toward the aorta, which lies on top of the vertebral body (Fig. 1 8-3). When the body is rotated 30 degrees for the AP oblique projection (LPO or RPO position), the lower kidney lies perpendicular and the up­ per kidney l ies parallel to the I R . The kid­ neys normal ly extend from the level of the superior border of T 1 2 to the level of the transverse processes of L3 in persons of sthenic build; they are somewhat higher in individuals of hypersthenic habitus and somewhat lower in those of asthenic habi­ tus. Because of the large space occupied by the liver, the right kidney is slightly lower in position than the left kidney.

The outer covering of the kidney is called the renal capsule. The capsule is a semi-transparent membrane that is contin­ uous with the outer coat of the ureter. Each kidney is embedded in a mass of fatty tissue called the adipose capsule. The capsule and kidney are enveloped in a sheath of superficial fascia, the renal fas­ cia, which is attached to the diaphragm, lumbar vertebrae, peritoneum, and other adjacent structures. The kidneys are sup­ ported in a fairly fixed position, partially through the fascial attachments and par­ tially by the surrounding organs. They have a respiratory movement of approxi­ mately I i nch (2.5 cm) and normall y drop no more than 2 i nches (5 cm) in the change from supine to upright position. The concave medial border of each kid­ ney has a longitudinal sl it, or hilum, for transmission of the blood and lymphatic vessels, nerves, and ureter (Fig. 1 8-4). The hilum expands into the body of the kidney to form a central cavity called the renal sinus. The renal sinus is a fat-fil led space urrounding the renal pelvis and vessels.

B

A

Fig. 1 8-3 A, Axial CT image through the center of the kidney. Note the 30 degree anterior (arrows). B, Axial CT image of the upper abdomen. Note supe­ rior aspect of the right kidney and mid portion of the left kidney demonstrating a lower placed left kidney.

angulation of the kidneys

1 96

(From Kelley LL Peterson C: Sectional anatomy. St Louis. 1 997. Mosby.)

Each kidney has an outer renal cortex and an inner renal medulla. The renal medulla, composed mainly of the collect­ ing tubules that give it a striated appear­ ance, consists of 8 to 1 5 cone-shaped seg­ ments cal led the renaL pyramids. The apices of the segments converge toward the renal sinus to drain into the pelvicalyceal y tem. The more compact renal cortex lies between the periphery of the organ and the ba es of the medullary segments and ex­ tends medially between the pyramids to the renal sinus. These extensions of the cortex are called renal columns. The essential microscopic components of the parenchyma of the kidney are called nephrons (Fig. 1 8-5). Each kidney con­ tains approxi mately I mil lion of these tubular structures. The individual nephron i composed of a renal corpuscle and a re­ nal tubule. The renal corpuscle consists of a double-walled membranous cup called the glomerular capsule ( Bowman's cap­ su le) and a cluster of blood capi llaries called the glomerulus. The glomerulus is formed by a minute branch of the renal artery entering the capsule and dividing into capi llaries. The capillaries then turn back and, as they ascend, unite to form a ingle vessel leaving the capsule.

The vessel enteri ng the capsule is called the afferent arteriole, and the one leaving the capsule is termed the efferent arteriole. After exiting the glomerular capsules, the efferent arterioles form the capil lary network surrounding the straight and convoluted tubules, and these capil­ laries reunite and continue on to commu­ nicate with the renal veins. The thin inner wall of the capsule closely adheres to the capil lary coil s and is separated by a comparatively wide space from the outer layer, which is con­ tinuous with the beginning of a renal tubule. The glomerulus serves as a filter for the blood, permitting water and fi nely dissolved substances to pass through the wal ls of the capi l laries into the capsule. The change from fil trate to urine is caused in part by the water and the usable dis­ solved substances being absorbed through the epithelial lining of the tubules into the surrounding capil l ary network. Each renal tubule continues from a glomerular capsule in the cortex of the kidney and then travels a circuitous path through the cortical and medullary sub­ stances, becoming the proximal convo­ luted tubule, the nephron loop (loop of Henle), and the distal convoluted tubule.

The distal convoluted tubule opens into the collecting ducts that begin in the cor­ tex. The collecting ducts converge toward the renal pelvis and unite along their course so that each group within the pyra­ mid forms a central tubule that opens at a renal papilla and drains its tributaries into the mi nor calyx. The calyces are cup-shaped stems aris­ ing at the sides of the papilla of each renal pyramid. Each calyx encloses one or more papil lae, so that there are usually fewer ca­ l yces than pyramids. The begi nning branches are called the minor calyces (numbering from 4 to 1 3), and they unite to form two or three larger tubes called the major calyces. The major calyces unite to form the expanded, funnel-shaped renal pelvis. The wide, upper portion of the re­ nal pelvis lies within the hilum, and its ta­ pering lower part passes through the hilum to become continuous with the ureter.

Afferent arteriole Efferent arteriole

�=��-- Renal capsule

Cortex

Proximal con­ voluted tubule

Renal medulla Renal papilla

Renal pyramid

Hilum

Descending limb of Henle's loop

Renal column Renal --if-llill" pelvis

.�Sii;;;;;��[5..-tl1-

Minor calyx Medulla Major calyx

Fig. 1 8-4 Midcoronal section of kidney.

Collecting duct

Ascending limb of Henle's loop

�

R.,ol poOUo

Fig. 1 8-5 Diagram of nephron and collecting duct.

1 97

Ureters

U rinary Bladder

Each ureter is 1 0 to 1 2 inches (25 to 30 cm) long. It descends behind the peri­ toneum and in front of the psoas muscle and the transverse processes of the lumbar vertebrae, passes i nferiorly and posteri­ orly in front of the sacral wing, and then curves anteriorly and medial ly to enter the posterolateral surface of the urinary blad­ der at approximately the level of the is­ chial spine. The ureters convey the urine from the renal pelves to the bladder by slow, rhythmic peristaltic contractions.

The urinary bladder is a musculomem­ branous sac that serves as a reservoir for urine. The bladder is situated immediately posterior and superior to the pubic sym­ physis and is directly anterior to the rec­ tum in the male and anterior to the vaginal canal in the female. The apex of the blad­ der is at the anterosuperior aspect and is adjacent to the superior aspect of the pu­ bic symphysi . The mo t fixed part of the bladder is the neck, which rests on the prostate in the male and on the pelvic di­ aphragm in the female.

The bladder varies in size, shape, and position according to its content. It is freely movable and is held in position by folds of the peritoneum. When empty, the bladder is located in the pelvic cavity. As the blad­ der fills, it gradually assumes an oval shape while expanding superiorly and anteriorly into the abdominal cavity. The adult blad­ der can hold approximately 500 ml of fluid when completely full. The desire for mic­ turition (urination) occurs when about 250 ml of urine is in the bladder. The ureters enter the posterior wall of the bladder at the lateral margins of the su­ perior part of its base and pass obliquely through the wall to their respective internal orifices (Fig. 1 8-6). The e two opening are about I inch (2.5 cm) apart when the bladder is empty and about 2 inches (5 cm) apart when the bladder is distended. The openings are equidistant from the internal urethral orifice, which is situated at the neck ( lowest PaJt) of the bladder. The tri­ angular area between the three orifices is called the trigone. The mucosa over the trigone is always smooth, whereas the re­ mainder of the lining contains folds, called rugae, when the bladder is empty.

Fig. 1 8-6 Anterior view of the urinary bladder.

B

A

Bladder Uterus Bladder apex Pubic symphysis Urethra

Pubic symphysis Base of bladder

Prostatic urethra Membranous urethra

Rectum Spongy urethra

Fig. 1 8-7 A, Midsagittal section through female pelvis. B, Male pelvis.

1 98

Rectum

Ureth ra

Prostate

The urethra, which conveys the urine out of the body, is a narrow, musculomembra­ nous tube with a sphincter type of muscle at the neck of the bladder. The urethra arises at the i nternal urethral orifice in the urinary bladder and extends about I Y'2 inches ( 3 . 8 cm) in the female and 7 to 8 inches ( 1 7 . 8 to 20 cm) in the male. The female urethra passes along the thick anterior wall of the vagina to the ex­ ternal urethral orifice, which is located in the vestibule about I i nch (2.5 cm) ante­ rior to the vaginal opening (see Fig. 1 8-6). The male urethra extends from the blad­ der to the end of the penis and is divided into prostatic, membranous, and spongy portions (Fig. 1 8-7). The prostatic portion is about I inch (2.5 cm) in length, reaches from the bladder to the floor of the pelvis, and is completely surrounded by the prostate. The membranous portion of the canal passes through the urogenital di­ aphragm; it is slightly constricted and about Y'2 inch ( 1 .3 cm) long. The spongy portion passes through the shaft of the pe­ nis, extending from the floor of the pelvis to the external urethral orifice. The distal prostatic, membranous, and spongy parts of the male urethra also serve as the ex­ cretory canal of the reproductive system.

The prostate is a smal l glandular body surrounding the proximal part of the male urethra and is situated just posterior to the inferior portion of the pubic symphysis. The prostate is considered part of the male reproductive system but, because of its close proximity to the bladder, is com­ monly described with the urinary system. The conical base of the prostate is at­ tached to the inferior surface of the uri­ nary bladder, and its apex is in contact with the pelvic diaphragm. The prostate measures about l � inches (3.8 cm) trans­ versely and % inch ( 1 .9 cm) anteroposte­ rioriy at its base; vertical ly the prostate is approximately I inch (2.5 cm) long. The prostate gland secretes a mi lky fluid that combines with semen from the seminal vesicles and vas deferens. These secre­ tions enter the urethra via ducts in the pro­ static urethra.

SUM MARY OF ANATOMY* Urinary system (excretory system)

kidneys (2) ureters (2) urinary bladder urethra Suprarenal glands (adrenal glands)

medullary portion cortical portion

Kidneys

Urinary bladder

adipose capsule renal fascia hilum renal capsule renal sinus renal cortex renal columns renal medulla renal pyramids nephrons renal corpuscle glomerular capsule (Bowman's capsule) glomerulus afferent arteriole efferent arteriole renal tubule proximal convoluted tubule nephron loop (Loop of Henle) distal convoluted tubule collecting ducts renal papilla calyces minor calyces major calyces renal pelvis

apex base neck trigone rugae Urethra

male urethra prostatic membranous spongy Prostate

'See Addendum at the end of the volume for a summary of the changes in the anatomic terms that were introduced in the 9th edition.

199

SUM MARY OF PATHOLOGY Condition

Definition

Benign Prostatic Hyperplasia CBPH)

Enlargement of the prostate

Calculus

Abnormal concretion of mineral salts. often called a stone

Carcinoma

Malignant new growth composed of epithelial cells

Bladder

Carcinoma located in the bladder

Renal Cell

Carcinoma located in the kidney

Congenital Anomaly Duplicate Collecting System

Two renal pelvi and/or ureters from the same kidney

Horseshoe Kidney

Fusion of the kidneys. usually at the lower poles

Pelvic Kidney

Kidney that fails to ascend and remains in the pelviS

Cystitis

Inflammation of the bladder

Fistula

Abnormal connection between two internal organs or between an organ and the body surface

Glomerulonephritis

Inflammation of the capillary loops in the glomeruli of the kidney

Hydronephrosis

Distension of the renal pelvis and calyces with urine

Polycystic Kidney

Massive enlargement of the kidney with the formation of many cysts

Pyelonephritis

Inflammation of the kidney and renal pelviS

Renal Hypertension

Increased blood pressure to the kidneys

Renal Obstruction

Condition preventing the normal flow of urine through the urinary system

Stenosis

Narrowing or contraction of a passage

Tumor

New tissue growth where cell proliferation is uncontrolled

Wilms'

200

Abnormality present since birth

Most common childhood abdominal neoplasm affecting the kidney

Ureterocele

Ballooning of the lower end of the ureter into the bladder

Veslcoureteral Reflux

Backward flow of urine from the bladder into the ureters

EXPOSURE TEC H N IQUE CHART ESSE NTIAL PROJ ECTI ONS U RI NARY

SYSTEM

Part

em

kVp·

tm

mA

mAs

Urinary System (Urography)t AP AP Oblique Lateral Lateral (decubitus)

21 24 27 30

75 75 90 95

0.08 0.09 0.1 1 0.1 1

200s 200s 200s 200s

16 18 22 22

48 48 48 48

Retrograde Urographyt AP

21

75

0.08

200s

16

Urinary Bladdert AP & PA Axial AP Oblique Lateral

18 21 31

75 75 95

0.06 0.08 0.24

200s 200s 200s

Male Cystourethrogramt AP Oblique

21

75

0.08

200s

AEC

SID

in in in in

IR

Dose! (mrad)

43 em 43 em 43 em 43 em

1 85 222 916 1 040

48 in

35 x 43 em

1 85

12 16 48

48 in 48 in 48 in

24 x 30 em 24 x 30 em 24 x 30 em

1 48 1 85 1 269

16

48 in

24 x 30 em

1 85

35 35 35 35

x x x x

s.

Small focal spot. *kVp values are for a 3-phase 1 2-pulse generator. IRelative doses for comparison use. All doses are skin entrance for average adult at cm indicated. IBucky. 1 6: 1 Grid. Screen/Film Speed 300.

201

.::�.

U R I NARY SYSTEM RADI OGRAPHY

Overview Radiography of the urinary system com­ prises numerous specialized procedures, each of which requires the use of an arti­ ficial contrast medium and each of which was evolved to serve a specific purpose. The specialized procedures are pre­ ceded by a plain, or scout, radiograph of the abdominopelvic areas for the detec­ tion of abnormal ities demonstrable by this mean . The prelimjnary examjnation may consist of no more than an AP projection of the abdomen. When indicated, oblique and/or lateral projections are taken to lo­ cal ize calcium and tumor masses, and an upright position may be used to demon­ strate the mobility of the kidneys.

Prelimi nary radiography can usual ly demonstrate the position and mobility of the kidneys and usually their size and shape. This is possible because of the con­ trast furnished by the radiolucent fatty cap­ sule surrounding the kidney . Visualization of the thin-walled drainage, or collecting, system (calyces and pelves, ureters, urinary bladder, and urethra) requires that the canals be filled with a contrast medium. The urinary bladder is outlined when it is filled with urine, but it is not adequately demonstrated. The ureters and the urethra cannot be distinguished on preliminary radiographs.

CONTRAST STUDIES For the del i neation and differentiation of cysts and tumor masses situated within the kidney, the renal parenchyma is opaci­ fied by an intravenously introduced or­ gan ic, iodi nated contrast medium and then radiographed by tomography or CT The contrast solution may be introduced into the vein by rapid i njection or by infu­ sion. These procedures are respectively called bolus injection nephrotomography (Fig. 1 8-8) and infusion nephrotomogra­ phy (Fig. 1 8-9). Angiographic procedures are used to investigate the blood vessels of the kid­ neys and the suprarenal gland (Chapter 26). An example of the direct injection of contrast medium i nto the renal artery is shown in Fig. 1 8- 1 0. Radiologic i nvestigations of the renal drainage, or collecting, system are per­ formed by various procedures classified un­ der the general term urography. This term embraces two regularly used techniques for filling the uri nary canals with a contrast medium. I maging of cutaneous urinary di­ versions has been described by Long. I ' Long BW: Radiography of cutaneous urinary diver­ ions, Radiol TecilnoI 60( 2): 1 09, 1 988.

Fig. 1 8-8 Bolus injection nephrotomogram .

Kidney !---=-=�

_ _ _

Major calyx

Renal pelviS

Ureter

Fig. 1 8-9 Infusion nephrotomogram.

202

Antegrade filling

Antegrade filling techniques allow the contrast medium to enter the kidney in the normal direction of blood flow. In selec­ tive patients this is done by introducing the contra t material directly into the kid­ ney through a percutaneous puncture of the renal pelvis-a technjque caJled per­ cutaneou antegrade urography. M uch more commonly used is the physiologic technique, in which the contrast agent is generally admin istered intravenously. This technique is called excretory or in­ travenous urography (/VU) and is shown in Fig. 1 8- 1 1 .

The excretory techillque of urography is used in examinations of the upper Uli nary tracts in infants and children and is gener­ ally considered to be the preferred tech­ nique in adults unless use of the retrograde technique is definitely indicated. Since the contrast medium is administered i ntra­ venously and all parts of the urinary system are normally demonstrated, the excretory technique is correctly referred to as intra­ venous urography. The term pyelography refers to the radiographic demonstration of the renal pelves and calyces. For years the examjnation has been erroneously called an intravenous pyelogram (IVP).

Fig. I S- 1 0 Selective right renal arteriogram.

Once the opaque contrast medium en­ ters the bloodstream, it is conveyed to the renal glomeruli and is di scharged into the capsules w i th the glomerular filtrate, which is excreted as urine. With the reab­ sorption of water the contrast material be­ comes sufficiently concentrated to render the urinary canals radiopaque. The urinary bladder is well outl ined by this technique, and satisfactory voiding urethrogram may be obtained.

Fig. I S- I I Excretory urogram. 203

Fig. 1 8- 1 2 Retrograde urogram.

Fig. 1 8- 1 3 Voiding study after routine injection IVU. Dilation of proximal urethra (arrows) is the result of urethral stricture.

Contrast­ filled bladder �----

Catheter in urethra

Fig. 1 8- 1 4 Voiding studies of same patient as in Fig. 1 8- 1 3 after infusion nephrourography. Note the increase in opacification of contrast-filled cavities by this method and the bladder diverticulum (arrows).

204

Fig. 1 8- 1 5 Cystogram.

Retrograde filling

In some procedures involving the urinary system, the contrast material is introduced against the normal flow. This is called ret­ rograde urography (Fig. 1 8- 1 2). The con­ trast medium is injected directly into the canals by means of ureteral catheterization for contrast fi lling of the upper urinary tract and by means of urethral catheteriza­ tion for contrast filling of the lower part of the urinary tract. Cystoscopy is required to localize the vesicoureteral orifices for the passage of ureteral catheters. Retrograde urographic examjnation of the proximal uri nary tract is primarily a urologic procedure. Catheterization and contrast fi ll ing of the urinary canals are performed by the attending urologist in conjunction with a physical or endoscopic examination. This technique enables the urologist to obtain catheterized specimens of urine directly from each renal pelvis.

Fig. 1 8- 1 6

Because the canals can be fully distended by direct injection of the contrast agent, the retrograde urographic exami nation sometimes provides more i nformation about the anatomy of the different parts of the collecting system than can be obtained by the excretory technique. For the retro­ grade procedure an evaluation of kidney function depends on an intravenously ad­ ministered dye substance to stain the color of the urine subsequently trickling through the respective ureteral catheters. Both the antegrade and retrograde tech­ niques of examination are occasionally re­ quired for a complete urologic study.

Cystoureterogram: AP bladder, showing distal ureters.

Fig. 1 8· 1 7

I nvestigations of the lower urinary tract-the bladder, lower ureters, and urethra-are usually made by the retro­ grade technique, which requires no instru­ mentation beyond passage of a urethral catheter. However, investigations may also be made by the physiologic technique (Figs. 1 8- 1 3 and 1 8- 1 4). Bladder examina­ tions are usually denoted by the general term cystography (Fig. 1 8- 1 5). A proce­ dure understood to include inspection of the lower ureters is cystoureterography (Fig. 1 8- 1 6), and a procedure understood to include inspection of the urethra is cys­ tourethrography (Fig. 1 8- 1 7).

Injection cystourethrogram showing urethra in male

patient.

205

Contrast media

Retrograde urography (Figs. 1 8- 1 8 and 1 8- 1 9) was first performed in 1 904 with the introduction of air into the urinary bladder. [n 1 906 retrograde urography and cystog­ raphy were performed with the first opaque medium, a colloidal silver preparation that is no longer used. Silver iodide, which is a nontoxic inorganic compound, was intro­ duced in 1 9 1 1 . Sodium iodide and sodium bromide, also inorganic compounds, were fir t used for retrograde urography in 1 9 1 8. The bromides and iodides are no longer widely used for examinations of the renal pelves and ureters because they in'itate the mucosa and commonly cause considerable patient discomfort. Becau e a large quantity of solution is required to fill the uri nary bladder, iodi­ nated salts in concentrations of 30% or Ie are used in cystography. A large se­ lection of commercially available contrast media may be used for all types of radio­ graphic examinations of the urinary sys­ tem. It i important to review the product insert packaged with every contrast agent.

Excretory urography (Figs. 1 8-20 and 1 8-2 1 ) was first reported by Rowntree et al in 1 923 . ' These i nvestigators used a 1 0% solution of chemically pure sodium iodide as the contrast medi um. However, this agent was excreted too slowly to give a satisfactory demonstration of the renal pelves and ureters, and it also proved too toxic for functional distribution. Early in 1 929, Roseno and Jepkins2 introduced a compound containing sodium iodide and urea. The latter constituent, which is one of the nitrogenous substances removed from the blood and el iminated by the kid­ neys, served to accelerate excretion and thus quickly fill the renal pelves with opacified urine. Although satisfactory re­ nal images were obtained with this com­ pound, patients experienced considerable di tress as a result of its toxicity. [n 1 929, Swick developed the organic compound Uroselectan, which had an io­ dine content of 42%. The present-day ionic contrast media for excretory urogra­ phy are the result of extensive research by many investigators. These media are available under various trade names in concentrations ranging from approxi­ mately 50% to 70% . Sterile solutions of the media are supplied in dose-size am­ pules or vials. I Rowntree LG et al: Roentgenography of the urinary tract during excretion of sodium iodide, lAMA

8 : 368, 1 923.

2Roseno A, Jepkins H: I ntravenous pyelography, FOrlschr Roentgenstr 39:859, 1 929. Abstract: Am 1 Roentgeno/ 22:685, 1 929.

206

In the early I 970s, research was initi­ ated to develop nonionic contrast media. Development progressed, and several nonionic contrast agents are currently available for urographic, vascular, and in­ trathecal injection. Al though non ionic contrast media are generally less likely to cause a reaction in the patient, they are twice as expen ive as ionic agents. Many institutions have developed crite­ ria to determine which patient receives which contrast medium. The choice of whether to use an ionic or nonionic con­ trast medium depends on patient ri k and economics.

Fig. 1 8- 1 8 Retrograde urogram with contrast medium-filled right renal pelvis and catheter in left renal pelvis.

Fig. 1 8- 19 Retrograde urogram,

Fig. 1 8-20 Excretory urogram. 1 0 minutes after contrast medium injection.

Fig. 1 8-21 Excretory urogram on same patient as in Fig, 1 8-20. 25 minutes ofter contrast medium injection,

207

Adverse reactions to iodinated

Preparation of intestinal tract

media

Although unobstructed visualization of the urinary tracts requires that the intestinal tract be free of gas and solid fecal material (Fig. 1 8-22), bowel preparation is not at­ tempted in infants and children. Further­ more, the use of cleansing measures in adults depends on the condition of the pa­ tient. Gas (particularly swal lowed air, which is quickly dispersed through the small bowel ) rather than fecal material usually interferes with the examination.

The iodi nated organic preparations that are compounded for urologic examina­ tions are of low toxicity. Consequently, adverse reactions are usual ly mild and of short duration. The characteri tic reac­ tions are a feeling of warmth, fl ushing, and sometime a few hives. Occa ional ly, nausea, vomiting, and edema of the respi­ ratory mucous membrane result. Severe and serious reactions occur only rarely but are always a possibility. Therefore the clinical history of each patient must be carefully checked, and the patient must be kept under careful observation for any sign of systemic reaction . Most reactions to contrast media occur within the first 5 minutes after administration. Therefore the patient should not be left unattended during this time period. Emergency equip­ ment and medication to treat adverse reac­ tions must be readily avai lable.

Hope and Campoy ' recommended that infants and children be given a carbonated soft drink to distend the stomach with gas. By this maneuver, the gas-containing in­ testinal loops are usually pushed i nferi­ orly and the upper urinary tracts, particu­ larly those on the left side of the body, are then clearly visualized through the outline of the gas-fi l led stomach. Hope and Campoy stated that the aerated drink should be given in an amount adequate to fully inflate the stomach: at least 2 ounces are required for a newborn infant, and a ful l 1 2 ounces are required for a child 7 or 8 years old. Tn conjunction with the car­ bonated drink, Hope and Campoy recom­ mended using a highly concentrated con­ trast medi um. A gas-distended stomach is shown in Fig. 1 8-23. ' Hope JW, Campoy F: The use of carbonated bever­ ages in pediatric excretory urography, Radiology 64:66, 1 955.

Renal calyces

Renal pelvis Abdominal ureter

Pelvic ureter

Urinary bladder

Fig. 1 8-22 Preliminary AP abdomen for urogram.

208

Fig. 1 8-23 Supine urogram at 1 5-minute interval with gas-filled stomach.

Berdon, Baker, and Leonidas2 stated that the prone position resolves the prob­ lem of obscuring gas in a majority of pa­ tients ( Figs. 1 8-24 and 1 8-25). Therefore it is not necessary to inflate the stomach with air alone or with air as part of an aer­ ated drink. By exerting pressure on the ab­ domen, the prone position moves the gas l aterally away from the pelvicalyceal structures. Gas in the antral portion of the stomach is displaced into its fundic por­ tion, gas in the transverse colon shifts into the ascending and descending segments, and gas in the sigmoid colon shifts into the descending colon and rectum. These investigators noted, however, that the prone position occasionally fails to pro­ duce the de ired result in small infants when the small intestine is dilated. Ga tric inflation also fails in these patients be­ cause the dilated small intestine merely elevates the gas-fi l led stomach and thus does not improve visualization. They rec­ ommended examination of such infants after the intestinal gas has passed.

Preparation of patient

Medical opinion concerning preparative measures varies widely. However, with modifications as required, the following procedure seems to be in general use: When time permits, have the patient follow a low-residue diet for I to 2 days to prevent gas formation caused by ex­ cessive fermentation of the intestinal contents. Have the patient eat a light evening meal on the day before the examination. When indicated by costive bowel action, administer a non-gas-forming laxative the evening before the examination. Have the patient take nothing by mouth after midnight on the day of the exam­ i nation. However, the patient should not be dehydrated. Patients with multi­ ple myeloma, high uric acid levels, or diabetes must be well hydrated before I V U is performed; these patients are at i ncreased risk for contrast medium­ induced renal failure if they are dehy­ drated.

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rn preparation for retrograde urogra­ phy, have the patient drink a large

amount of water (4 or 5 cups) for sev­ eral hours before the exami nation to en­ sure excretion of urine in an amount sufficient for bilateral catheterized specimens and renal function tests. Note that no patient preparation is usu­ ally necessary for examinations of the lower urinary tract. Outpatients should be given explicit di­ rections regarding any order from the physician pertai ning to diet, fluid intake, and laxatives or other medication. The pa­ tient should also be given a suitable ex­ planation for each preparative measure to ensure cooperation. •

2Berdon WE. Baker DH, Leonidas J: Prone radiog­ raphy in intravenous pyelography in infants and chil­ dren, Am J Roelllgello/ 1 03 :444, 1 968.

Fig. 1 8-24 Urogram: supine position. Intestinal gas obscuring the left kidney.

Fig. 1 8-25 Urogram: prone position. in the same patient as in Fig. 1 8-24. Visualization of left kidney and ureter is markedly improved.

209

EQUIPMENT A combination cystoscopic-radiographic unit facilitates retrograde urographic pro­ cedures requiring cystoscopy. Any stan­ dard radiographic table is suitable for the performance of preliminary excretory urography, a well as most retrograde stud­ ies of the bladder and urethra. The cysto­ scopic unit is also used for these proce­ dures; however, for the patient's comfort, the table should have an extensible leg rest. I nfusion nephrourography requires a table equi pped with tomographic appara­ tu . Tomography should be performed when intestinal gas obscures some of the underlying structures or when hyper­ sthenic patients are being examined ( Figs. 1 8-26 to 1 8-28). For the patient's comfort and to prevent delays during the examination, all prepa­ rations for the examination should be completed before the patient is placed on the table. I n addition to an identification and side marker, excretory urographic tudies require a time-interval marker for each postinjection study. Body-position markers (supi ne, prone, upright or semi­ upright, Trendelenburg, decubitus) should also be used.

Some institutions perform excretory urograms (proximal urinary tract studies) using 24 X 30 cm or 30 X 35 cm IRs placed crosswise, but these studies can also be made on 35 X 43 cm IRs placed lengthwise. The upright study is made on a 35 X 43 cm IR because it is taken to demonstrate the mobility of the kidneys and to outl ine the lower ureters and blad­ der. Studies of the bladder before and af­ ter voiding are usual ly taken on 24 X 30 cm ( I O X 1 2 inch) IRs.

Fig. 1 8-26 Urogram: AP projection.

210

The fol lowing guidelines are ob erved in preparing additional equipment for the examination: Have an emergency cart fully equipped and conveniently placed. Arrange the instruments for injection of the contrast agent on a smal l, movable table or on a tray. Have frequently used sterile items read­ ily available. Disposable syringes and needles are available in standard sizes and are widely used in this procedure. Have required nonsterile items avail­ able: a tourniquet, a small waste basin, an emesis basin, general disposable wipes, one or two bottles of contrast medium, and a small prepared dres ing for application to the puncture site. Have iodine or alcohol wipes available. Provide a folded towel or a small pillow that can be placed under the patient's elbow to relieve pressure during the injection. •

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Fig. 1 8-27 Urogram: AP projection using tomography.

PROCEDURE Image quality and exposure technique

Urograms should have the same contra t, den ity, and degree of soft tissue density as do abdominal radiographs. The radi­ ographs must show a sharply defined out­ line of the kidneys, lower border of the liver, and lateral margin of the psoas mus­ cles. The amount of bone detail visible in these studies varies according to the thick­ ness of the abdomen (Fig. 1 8-29). Motion control

An immobilization band u ual ly is not ap­ plied over the upper abdomen in uro­ graphic examinations because the resul­ tant pre sure may i nterfere with the pas age of fl uid through the ureters and may at 0 cause distortion of the canals. Thus the elimination of motion in uro­ graphic examinations depends on the ex­ posure time and on securing the ful l coop­ eration of the patient. The examination procedure should be explained so that the adult patient is pre­ pared for any transitory distress caused by the injection of contrast solution or by the cy to copic procedure. The patient should be a sured that everything possible will be done for the patient's comfort. The suc­ cess of the examinations depends in large part on the abi lity of the radiographer to gain the confidence of the patient.

Fig. 1 8-28 Urogram: AP oblique projection, LPO position, using tomography. Note left kId­ ney is perpendicular to IR.

Fig. 1 8-29 AP abdomen showing margins of the kidney (dots), liver (dashes), and psoas muscles (dot-dash lines).

21 1

Ureteral compression

Fig. 1 8-30 Ureteral compression device in place for urogram.

In excretory urography, compression i s sometimes applied over the distal ends of the ureters. This is done to retard flow of the opacified urine into the bladder and thus ensure adequate filling of the renal pelves and calyces. If compression is used, it must be placed so that the pressure over the distal ends of the ureters is centered at the level of ASIS. As much pressure as the patient can comfortabl y tolerate is then ap­ plied with the immobilization band (Figs. 1 8-30 and 1 8-3 1 ). The pressure should be released slowly when the compression de­ vice is removed to avoid the possibility of visceral rupture. Compression is generally contraindicated if a patient has urinary stones, an abdominal mass or aneurysm, a colostomy, a suprapubic catheter, or trau­ matic i nj ury. As a result of improvements in contrast agents, ureteral compression is not rou­ tinely used in most health care facilities. With the i ncreased doses of contrast medium now employed, mo t of the ureteral area is usuall y demonstrated over a series of radiographs. Respiration

For the purpose of comparison, all expo­ sures are made at the end of the same phase of breathing-at the end of expira­ tion unless otherwise requested. Because the normal respiratory excursion of the kidneys varies from � to 1 \12 i nches ( 1 .3 to 3.8 cm), it is occasionall y possible to differentiate renal shadows from other shadows by making an exposure at a dif­ ferent phase of arrested respiration. When an exposure is made at a respiratory phase different from what is usually used, the image should be so marked.

Ureteral compression device

Fig. 1 8-31 Urogram showing ureteral compression device in proper position over distal ureters.

21 2

Renal Parenchyma

Fig. 1 8-51 Infusion nephrotomogram: AP projection at 9-cm level.

Fig. 1 8-53 Infusion nephrotomogram: AP projection, demonstrating para­ pelvic cyst on right kidney (arrows).

Fig. 1 8-52 Infusion nephrotomogram: AP projection at 5-cm level.

Fig. 1 8-54 Infusion nephrotomogram: lateral projec­ tion, demonstrating para pelvic cyst (arrows).

223

PERCUTANEOUS RENAL PUNCTURE Percutaneous renal puncture, introduced by Lindblom,J·2 is a radiologic procedure for the investigation of renal masses. Specifically, it is used to differentiate cysts and tumors of the renal parenchyma. This procedure is performed by direct in­ jection of a contrast medium into the cyst under fl uoroscopic control (Figs. 1 8-55 and 1 8-56). Ultrasonography of the kid­ ney has practically eliminated the need for percutaneous renal puncture. Most masses that are clearly diagnosed as cystic by ul­ trasound examination are not surgically managed. ' Lindblom K: Percutaneous puncture of renal cysts and tumors, Acta Radio1 27:66, 1 946. 'Lindblom K: Diagnostic kidney puncture in cysts and tumors, Am J RoentgenoI 68:209, 1 952.

Fig. 1 8-55 Upright AP left kidney: percutaneous injection of iodinated contrast material and gas into renal cyst.

Fig. 1 8-56 AP projection left kidney, left lateral decubitus position, in the same patient as in Fig. 1 8-55.

224

In a similar procedure the renal pelvis is entered percutaneously for direct con­ trast fi l l i ng of the pelvicalyceal system i n elected patients with hydronephrosis.I.3 This procedure, called percutaneous ante­ grade pyelography to distinguish it from the retrograde technique of direct pelvica­ Iyceal fi l ling, is usuall y restricted to the i nve tigation of patients with marked hy­ dronephrosis and patients with suspected hydronephrosis for which conclusive i n­ formation is not gained by excretory or retrograde urography (Fig. 1 8-57). Normally, AP abdominal radiographs are obtained for this procedure, although other projections may be requested. ' Wickbom I : Pyelography after direct puncture of the renal pelvis, Acta RadioL 41 :505, 1 954. 2Weens HS, Florence TJ: The diagno is of hy­ dronephrosi by percutaneous renal puncture, J UroL 72:589, 1 954.

3Casey we, Goodwin WE: Percutaneous antegrade pyelography and hydronephrosis, J Urol 74: 1 64, 1 955.

Fig. 1 8-57 Percutaneous antegrade pyelo­ gram demonstrating hydronephrosis.

225

Pelvicalyceal System and U reters Retrograde U rography .. AP PROJECTION Retrograde urography requires that the ureter be catheterized so that a contrast agent can be injected directly into the pelvicalyceal ystem. This technique pro­ vides improved opacification of the renal collecting system but little physiologic in­ formation about the urinary sy tern. Indications and contraindications

If elevation of the thighs does not re­ duce the lumbar curve, a pillow is ad­ justed under the patient's head and shoul­ ders so that the back is in contact with the table. Most cystoscopic-radiographic ta­ bles are equipped with an adjustable leg rest to permit extension of the patient's legs for certain radiographic studies.

The urologist then performs catheteri­ zation of the ureters through a ureterocys­ toscope, which is a cystoscope with an arrangement that aids insertion of the catheters into the vesicoureteral orifices. After the endoscopic examination, the urologist passes a ureteral catheter well into one or both ureter (Fig. 1 8-59) and, leaving the catheters in position, usual ly withdraws the cystoscope.

The retrograde urogram is indicated for evaluation of the collecting system in pa­ tients who have renal insufficiency or who are al lergic to iodinated contrast media. Because the contrast medium is not intro­ duced into the circulatory system, the in­ cidence of reactions is reduced. Examination procedure

Like all examinations requiring i nstru­ mentation, retrograde urography is classi­ fied as an operative procedure. This com­ bined urologic-radiologic examination is carried out under careful aseptic condi­ tions by the attending urologist with the a i tance of a nurse and radiographer. The procedure is performed in a specially equipped cy toscopic-radiographic exam­ ining room that, because of its collaborative nature, may be located in the urology department or the radiology department. A nurse is responsible for the preparation of the instruments and the care and drap­ ing of the patient. One of the radiogra­ pher's responsibilities is to ensure that the overhead parts of the radiographic equip­ ment are free of du t for the protection of the operative field and the sterile layout. The radiographer positions the patient on the cystoscopic table with knees flexed over the stirrups of the adjustable leg sup­ port (Fig. 1 8-58). This is a modified lithotomy position; the true lithotomy poition requires acute flexion of the hips and knees. If a general anesthetic is not used, the radiographer explains the breathing pro­ cedure to the patient and checks the pa­ tient' position on the table. The kidney and the full extent of the ureter in pa­ tients of average height are included on a 35 X 43 cm IR when the third lumbar ver­ tebra is centered to the grid.

Fig. 1 8-58 Patient positioned on table for retrograde urography. modified lithotomy position.

Fig. 1 8-59 Retrograde urogram with catheters in proximal ureters: AP projection.

226

Pelvicalyceal System and U reters

After taking two catheterized speci­ mens of urine from each kidney for labo­ ratory tests--one specimen for culture and one for microscopic examination­ the urologist tests kidney function. For this test, a color dye is injected intra­ venously, and the function of each kidney is determined by the specified time re­ quired for the dye substance to appear in the urine as it trickles through the respec­ tive catheters. I m mediately after the kidney function test, the radiographer rechecks the posi­ tion of the patient and exposes the prelim­ inary IR (if this has not been done previ­ ously) so that the radiographs will be ready for i nspection by the time the kid­ ney function test has been completed. After reviewing the image, the urolo­ gist injects the contrast medium and pro­ ceeds with the urographic examination. When a bilateral examination is to be per­ formed, both sides are fi lled simultane­ ously to avoid subjecting the patient to un­ necessary radiation exposure. Additional studies in which only one side is refilled may then be made as i ndicated.

The most commonly used retrograde urographic series usuall y consists of three AP projections: the preli minary radi­ ograph showing the ureteral catheters in position (see Fig. 1 8-59), the pyelogram, and the ureterogram. Some urologists rec­ ommend that the head of the table be low­ ered 1 0 to 1 5 degrees for the pyelogram to prevent the contrast solution from escap­ ing into the ureters. Other urologists rec­ ommend that pressure be maintained on the syringe during the pyelographic expo­ sure to ensure complete filling of the pelvicalyceal system. The head of the table may be elevated 35 to 40 degrees for the ureterogram to demonstrate any tortu­ osity of the ureters and the mobility of the kidneys. Filling of the average normal renal pelvis requires 3 to 5 rnl of contrast solu­ tion; however, a larger quantity is required when the structure is dilated. The best in­ dex of complete filling, and the one most commonly used, is an indication from the patient as soon as a sense of fullness is felt in the back.

Fig. 1 8-60 Retrograde urogram with renal pelves filled: AP projection.

When both sides are to be filled, the urologist i njects the contrast solution through the catheters in an amount suffi­ cient to fil l the renal pelves and calyces. When signaled by the physician, the pa­ tient suspends respiration at the end of ex­ piration, and the exposure for the pyelo­ gram is then made (Fig. 1 8-60). After the pyelographic exposure, the IR is quickly changed and the head of the table may be elevated in preparation for the ureterogram. For this exposure the patient is instructed to inspire deeply and then sus­ pend respiration at the end of full expira­ tion. Simultaneously with the breathing procedure, the catheters are slowly with­ drawn to the lower ends of the ureters as the contrast solution is injected into the canals. At a signal from the urologist, the uretero­ graphic exposure is made (Fig. 1 8-6 1 ). Additional projections are sometimes required. RPO or LPO (AP oblique) pro­ jections are often necessary. Occasional ly a lateral projection, with the patient turned onto the affected side, is performed to demonstrate anterior displacement of a kidney or ureter and to delineate a peri­ nephric abscess. Lateral projections with the patient in the ventral or dorsal decubi­ tus position (as required) are also useful demonstrating the ureteropelvic region in patients with hydronephrosis.

Fig. 1 8-61 Retrograde urogram showing renal pelves and contrast-filled ureters: AP projection.

227

Urina ry Bladder, lower Ureters, U rethra, and Prostate With few exceptions, radiologic examina­ tions of the lower urinary tract are per­ formed with the retrograde technique of introducing contrast material. These ex­ aminations are identified, according to the specific purpose of the i nvestigation, by the terms cystography, cystoureterogra­ phy, cystourethrography, and prostatogra­ phy. Most often they are denoted by the general term cystography. Cystoscopy is not required before retrograde contrast fill ing of the lower urinary canals, but, when both examinations are indicated, they are usually performed in a single­ stage procedure to spare the patient prepa­ ration and instrumentation for separate examinations. When cystoscopy is not i n­ dicated, these examinations are best car­ ried out on an all-purpose radiographic table unless the combi nation table is equipped with an extensible leg rest. Indications and contraindications

Retrograde studies of the lower urinary tract are indicated for vesicoureteral re­ flux, recurrent lower urinary tract i nfec­ tion, neurogenic bladder, bladder trauma, lower urinary tract fistulae, urethral stric­ ture, and posterior urethral valves. Contra­ indications to lower urinary tract studies are related to catheterization of the urethra. Contrast media

The contrast agents used for contrast stud­ ies of the lower urinary tracts are ionic so­ lutions of either sodium or meglumine dia­ trizoates or the newer non ionic contrast media mentioned earl ier. These are the same organic compounds used for IVU, but their concentration is reduced for ret­ rograde urography. Injection equipment

The examinations are performed under careful aseptic conditions. I nfants, chil­ dren, and, usually, adults may be catheter­ ized before they are brought to the radiol­ ogy department. When the patient is to be catheterized in the radiology department, a sterile catheterization tray must be set up to specifications. Because of the dan­ ger of contamination in transferri ng a ster­ ile liquid from one container to another, the use of commercially available pre­ mixed contrast solutions is recommended.

228

Preliminary preparations

RETROGRADE CYSTOGRAPHY

The following guidelines are observed in preparing the patient for the examination: Protect the examination table from urine soilage with radiolucent plastic sheeting and disposable underpadding. Correctly arranged disposable padding does much to reduce soilage during voiding studies and consequently elim­ inates the need for extensive cleaning between patients. A suitable disposal receptacle should be available. A few minutes before the examination, accompany the patient to a lavatory. Give the patient supplies for perineal care, and instruct the patient to empty the bladder. Once the patient is prepared, place the patient on the examination table for the catheterization procedure. Patients are usuall y tense, primaril y be­ cause of embarrassment. It is important that they be given as much privacy as pos­ sible. Only the required personnel should be present during the examination, and patients should be properly draped and covered according to room temperature.

Contrast injection technique

In preparing for this examination, the fol­ lowing steps are observed: With the urethral catheter in place, ad­ just the patient in the supine position for a preliminary radiograph and the first cystogram. Usually, take cystograms of adult pa­ tients on 24 X 30 cm IRs placed length­ wise. Center the IR at the level of the soft tissue depression just above the most prominent point of the greater trochanters. This cen­ tering coincides with the middle area of a filled bladder of average size. Therefore the 30-cm IR will include the region of the distal end of the ureters for demon­ stration of ureteral reflux, and it will also include the prostate and proximal part of the male urethra. Have large IRs nearby for use when ureteral reflux is shown. Some radiolo­ gists request studies during contrast fill­ i ng of the bladder, as well as during voiding. After the preliminary radiograph is taken, the physician removes the catheter Contrast injection clamp and the bladder is drained in prepa­ For retrograde cystography (Figs. 1 8-62 ration for the i ntroduction of the contrast and 1 8-63), cystourethrography, and void­ material. After i ntroducing the contrast ing cystourethrography, the contrast mate­ agent, the physician clamps the catheter rial is introduced into the bladder by i n­ and tapes it to the thigh to keep it from be­ jection or infusion through a catheter ing displaced during position changes. passed into position by way of the urethral The initial cystographic images generally canal. A smal l, disposable Foley catheter consist of four projections: one AP, two AP is used to occlude the vesicourethral ori­ obliques, and one lateral. Additional stud­ fice in the examination of i nfants and chil­ ies, including voiding cystourethrograms, dren, and this catheter may be used in the are obtained as i ndicated. The Chassard­ examination of adults when interval stud­ Lapine method (see Chapter 7), often called ies are to be made for the detection of de­ the "squat shot," is sometimes used to ob­ tain an axial projection of the posterior sur­ layed ureteral refl ux. Studies are made during voiding for the face of the bladder and the lower end of the delineation of the urethral canal and for ureters when they are opacified. These pro­ the detection of ureteral reflux, which may jections of the bladder are also made when occur only during urination (Fig. 1 8-64). it is opacified by the excretory technique of When urethral studies are to be made dur­ urography. ing injection of contrast material, a soft­ rubber urethral-orifice acorn is fitted di­ rectly onto a contrast-loaded syringe for female patients and is usually fi lled onto a cannula attached to a clamp device for male patients.

•

•

•

•

•

•

•

Fig. 1 8-62 Retrograde cystogram after introduction of contrast media: AP projection.

Fig. 1 8-63 Retrograde cystogram after introduction of air: AP projection.

Fig. 1 8-64 Serial (polygraphic) voiding cystourethrograms in an infant girl with bilateral ureteral reflux (arrowheads). Urethra is normal. Vaginal reflux (arrows) is normal finding.

229

Urinary Bladder

.. AP AXIAL OR PA AXIAL PROJECTION Image receptor: 24 lengthwise

X

30 cm

Position of patient • Place the patient supine on the radio­ graphic table for the AP projection of the urinary bladder. NOTE: Preliminary (scout) and postinjection ra­ diographs are most commonly obtained with the patient supine. The prone po ition is some­ times used to i mage areas of the bladder not clearly seen on the AP axial projection. An AP axial projection using the Trendelenburg posi­ tion at 1 5 to 20 degrees and with the central ray directed vertical ly is sometimes used to demon­ strate the distal ends of the ureters. In this an­ gled position, the weight of the contained fluid stretches the bladder fundus superiorly, giving an unobstructed projection of the lower ureters and the vesicoureteral orifice areas.

Position of part

Central ray

• Center the midsagittal plane of the pa­ tient's body to the midline of the grid device. • Adj ust the patient's shoulders and hips so that they are equidistant from the IR. Place the patient's arms where they will not cast shadows on the IR. If the patient is positioned for a supine radiograph, have the patient's legs ex­ tended so that the lumbosacral area of the spine is arched enough to tilt the an­ terior pelvic bones inferiorly. In this po­ sition the pubic bones can more easily be projected below the bladder neck and proximal urethra (Fig. 1 8-6S ). • Center the I R 2 inches (S cm) above the upper border of the pubic symphysis (or at the pubic symphysis for voiding studies). • Respiration: S uspend at the end of ex­ piration.

AP • Angled 1 0 to I S degrees caudal to the center of the IR. The central ray should enter 2 inches (S cm) above the upper border of the pubic symphysis. When the bladder neck and proximal urethra are the main areas of interest, a s-degree ' caudal angulation of the central ray is usually sufficient to project the pubic bones below them. More or less angula­ tion may be necessary, depending on the amount of lordosis of the lumbar spine. With greater lordosis, less angulation may be needed (see Fig. 1 8-6S). PA • When performing PA axial projections of the bladder, direct the central ray through the region of the bladder neck at an angle of 1 0 to I S degrees cepha­ lad, entering about I inch (2.S cm) dis­ tal to the tip of the coccyx and exiting a little above the superior border of the pubic symphysis. If the prostate is the area of interest, the central ray is di­ rected 20 to 2S degrees cephalad to pro­ ject it above the pubic bones. For PA axial projections, the IR is centered to the central ray. • Perpendicular to the pubic symphysis for voiding studies.

•

•

Fig. 1 8-65 Retrograde cystogram . AP axial bladder with 1 5-degree caudal angulation of central ray.

230

Urinary Bladder

Structures shown

AP axial and PA axial projections demon­ strate the bladder filled with contrast medium (Figs. 1 8-66 and 1 8-67). If reflux is present, the distal ureters are also visualized.

EVALUATION CRITERIA

The fol lowi ng should be clearly demon­ strated: • Regions of the distal end of the ureters, bladder, and proximal portion of the urethra • Pubic bones projected below the blad­ der neck and proximal urethra • Short scale of contrast clearly demon­ strating contrast medium in the bladder, distal ureters, and proximal urethra

Fig. 1 8-66 Excretory cystogram: AP axial projection.

Fig. 1 8-67 Retrograde cystogram: AP axial projection. Note catheter in bladder.

231

U rinary Bladder

.. AP OBLIQUE PROJECTION RPO or LPO position

Image receptor: 24 lengthwise

Central roy •

x

30 cm

Position of patient •

Place the patient in the supine position on the radiographic table.

Position of port •

•

•

•

•

•

Rotate the patient 40 to 60 degrees RPO or LPO, according to the prefer­ ence of the examjning physician (Fig. 1 8-68). Adjust the patient so that the pubic arch closest to the table is aligned over the rlli dline of the grid. Extend and abduct the uppermost thigh enough to prevent its superimposition on the bladder area. Center the IR 2 inches (5 cm) above the upper border of the pubic symphysis and approxi mately 2 inches (5 cm) me­ dial to the upper ASIS (or at the pubic symphysis for voiding studies). Respiration: Suspend at the end of ex­ piration.

Perpendicular to the center of the IR. The CR will fal l 2 inches (5 cm) above the upper border of the pubic symphysis and 2 inches (5 cm) medjal to the upper ASIS. When the bladder neck and prox­ imal urethra are the main areas of inter­ est, a 1 O-degree caudal angulation of the central ray is usually sufficient to pro­ ject the pubic bones below them. Perpendicular at the level of the pubic symphysis for voiding studies.

Structures shown

Oblique projections demonstrate the blad­ der fi l led with the contrast medium. If re­ flux is present, the distal ureters are also visualized (Figs. 1 8-69 and 1 8-70).

������""-"--*11""�

-------

-

-� ------

-

.

-

Fig. 1 8-68 Retrograde cystogram : AP oblique bladder. RPO position.

232

Urinary Bladder

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Regions of the distal end of the ureters, bladder, and proximal portion of the urethra • Pubic bones projected below the blad­ der neck and proximal urethra • Short scale of contrast clearly demon­ strating the contrast medjum in the blad­ der, distal ureter , and proximal urethra • No superimposition of the bladder by the uppermost thjgh Voiding studies • Entire urethra visible and fi lled with the contrast medium • Urethra overlapping the thigh on oblique projections for improved visibility • Urethra lying posterior to the superim­ posed pubic and ischial rarm on the side down in oblique projections

Fig. 1 8-69 Excretory cystogram: AP oblique bladder, RPO position.

Fig. 1 8-70 Retrograde cystogram with catheter in bladder.

233

Urinary Bladder

'" LATERAL PROJECTION

Image receptor: 24 lengthwise

x

EVALUATION CRITERIA

Central ray

R or L position

30 cm

• Perpendicular to the IR and 2 inches (5 cm) above the upper border of the pu­ bic symphysis at the midcoronal plane Structures shown

Position of patient • Place the patient in the lateral recum­ bent position on either the right or left side, as indicated. Position of part

A lateral image demonstrates the bladder fi l led with the contrast medium. If reflux is .present, the distal ureters are also visu­ alized. Lateral projections demonstrate the anterior and posterior bladder walls and the base of the bladder (Fig. 1 8-72).

• Sl ightly flex the patient's knees to a comfortable position, and adjust the body so that the midcoronal plane is centered to the midline of the grid. • Flex the patient's elbows and place the hand under the head (Fig. 1 8-7 1 ). • Center the I R 2 inches (5 cm) above the upper border of the pubic symphysis at the midcoronal plane. • Respiration: Suspend at the end of expiration.

Fig. 1 8- 7 1 Cystogram: lateral projection.

234

The fol lowing should be clearly demon­ strated: • Regions of the distal end of the ureters, bladder, and proximal portion of the urethra • Short scale of contrast clearly demon­ strating the contrast medium in the bladder, distal ureters, and proximal urethra • B l adder and di stal ureters v i s ible through the pelvis • Superimposed hips and femur

Fig. 1 8-72 Cystogram: lateral projection.

Male Cystourethrography

'" AP OBLIQUE PROJECTION RPO or LPO position

Male cystourethrography may be pre­ ceded by an endoscopic examination, af­ ter which the bladder is catheterized so that it can be drained j ust before contra t material i injected. The fol lowing steps are ob erved: • Use 24 X 30 cm IRs placed lengthwise for cystourethrograms in adult male pa­ tients. • The patient is adjusted on the combina­ tion table so that the IR can be centered at the level of the superior border of the pubic symphysis. This centering coin­ cides with the root of the penis, and a 30-cm ( l 2-inch) I R will i nclude both the bladder and the external urethral orifice. • After i nspecting the preliminary radi­ ograph, the physician drains the blad­ der and withdraws the catheter. • The supine patient is adjusted in an oblique position so that the bladder neck and the entire urethra are delin­ eated as free of bony superimposition a po sible. Rotate the patient' body 35 to 40 degrees, and adjust it so that the elevated pubis is centered to the midline of the grid. The superimpo ed pubic and ischial rami of the down side and the body of the elevated pubis usu­ ally are projected anterior to the blad­ der neck, proximal urethra, and prostate (Fig. 1 8-73).

• The patient's lower knee is flexed only slightly to keep the soft tissues on the medial side of the thigh as near to the center of the IR as possible. • The elevated thigh is extended and re­ tracted enough to prevent overlapping. With the patient in the correct position, the physician i nserts the contrast­ loaded urethral syringe or the nozzle of a device such as the Brodney clamp i nto the urethral orifice. The physician then extends the penis along the soft tissues of the medial side of the lower thigh to obtain a uniform density of both the deep and the cavernous por­ tions of the urethral canal. •

�

• At a signal from the phy ician, instruct the patient to hold sti l l ; make the expo­ sure while the injection of the contrast material is continued to ensure filling of the entire urethra (Fig. 1 8-74). • The bladder may then be fil led with a contrast material so that a voiding study can be performed (Fig. 1 8-75). This i usually done without changing the pa­ tient's position. When a tanding-upright voiding tudy is required, the patient is adjusted before a vertical grid device and is supplied with a urinal. (Further in­ formation on positioning is provided on pp. 230 to 234 of this volume.)

-- .�

I

Fig. 1 8-73 Cystourethrogram : AP oblique projection. RPO position.

Bladder

Prostatic urethra Membranous urethra

Spongy (cavernous) urethra "'-----::.=--'--::"--.:

Fig. 1 8-74 Injection cystourethrogram: AP oblique urethra. RPO position.

Fig. 1 8-75 Voiding cystourethrogram : AP oblique urethra. LPO position.

235

Female Cystourethrography

AP PROJECTION INJ ECTION METHOD The female urethra averages 3 .5 cm in length. Its opening into the bladder is situ­ ated at the level of the superior border of the pubic symphysis. From this point the vessel slants obliquely inferiorly and ante­ riorly to its termination in the vestibule of the vulva, about I inch anterior to the vagi­ nal orifice. The female urethra is subject to conditions such as tumors, abscesses, di­ verticula, dilation, and strictures. It is also ubject to urinary incontinence during the stress of increased intraabdominal pressure such as occurs during sneezing or cough­ ing. In the investigation of abnormalities other than stress incontinence, contrast studies are made during the injection of contrast medium or during voiding. Cystourethrography is usually preceded by an endoscopic examination. For this reason, it may be performed by the at­ tending urologist or gynecologist with the assistance of a nurse and a radiographer. The following steps are ob erved: After the physical examination, the cys­ toscope is removed and a catheter is in­ serted into the bladder so that the blad­ der can be drained j ust before i njection of the contrast solution. The patient is adjusted in the supine po­ sition on the table. •

An 8 X 1 0 inch ( 1 8 X 24 cm) or 24 X 30 cm I R is placed lengthwise and cen­ tered at the level of the superior border of the pubic symphysis. A 5-degree caudal angulation of the central ray is usual ly sufficient to free the bladder neck of superimposition. • After inspecting the preliminary radi­ ograph, the physician drains the blad­ der and withdraws the catheter. The physician uses a syringe fitted with a blunt-nosed, soft-rubber acorn, which is held firmly against the urethral ori­ fice to prevent reflux as the contrast so­ l ution is injected during the exposure. ]n addition to the AP projection, oblique projection may also be re­ quired. For the oblique projections, the patient is rotated 35 to 40 degrees so that the urethra is posterior to the pubic symphysis. The uppermost thigh is then extended and abducted enough to pre­ vent overlapping. (Further information on positioning is provided on pp. 230 to 234 of this vol­ ume.) The physician fi lls the bladder for each voiding study to be made.

•

•

•

•

•

•

For an AP projection (Figs. 1 8-76 and 1 8-77), the patient is maintained in the supine position, or the head of the table is elevated enough to place the patient in a semiseated position. A lateral voiding study of the female vesicourethral canal is performed with the patient recumbent or upright. In ei­ ther case, the IR is centered at the level of the superior border of the pubic symphysis.

Metallic bead chain cystourethrography

The metallic bead chain technique of in­ vestigating anatomic abnormalities respon­ sible for stress incontinence in women was descri bed by Stevens and S mi th l in 1 937 and by Bames2 in 1 940. This technique is Stevens WE, Smith SP: Roentgenological examina­ tion of the female urethra, J Ural 37: 1 94, 1 937. 2Barnes AC: A method for evaluating the stress of urinary incontinence, Am J Obslel GYlleco/ 40:38 1 , 1 940.

•

•

Controst-filled bladder

Urethra

Fig. 1 8-76 Voiding cystourethrogram: AP projection.

236

Fig. 1 8-77 Serial voiding images showing four stages of bladder emptying.

Female Cystourethrography

used to delineate anatomic changes that oc­ cur in the shape and position of the bladder floor, in the posterior urethrovesical angle, in the position of the proximal urethral ori­ fice, and in the angle of i nclination of the urethral axi under the stress of increased intraabdominal pressure as exerted by the Val salva maneuver.

Comparison AP and lateral projections are made with the patient standing at rest (Figs. 1 8-78 and 1 8-79) and straining (Figs. 1 8-80 and 1 8-8 1 ).

Bladder

Metallic bead chain

Fig. 1 8-78 Upright cystourethrogram : resting AP projection.

Fig. 1 8-79 Upright cystourethrogram : resting lateral projection.

Fig. 1 8-80 Upright cystourethrogram: stress AP projection in the same patient as in Fig. 1 8-78.

Fig. 1 8-81 Upright cystourethrogram: stress lateral projection.

237

For this examination the physician ex­ tends a flexible metal lic bead chain through the urethral canal . The proximal portion of the chain rests within the blad­ der, and the distal end i taped to the thigh. For demon tration of the length of the ure­ thra, a small metal marker is attached with a piece of tape to the vaginal muco a just lateral to the urethral orifice. After instilla­ tion of the metal lic chain, a catheter is passed into the bladder, the contents of the bladder are drained, and an opaque con­ trast solution is injected. The catheter is re­ moved for the imaging procedure.

Hodgkinson, Doub, and Kel ly' recom­ mended the upright position, which uses gravity and thus simulates normal body activity. Two sets of images (AP and lat­ eral projections) are obtained, and the rest of the studies must be exposed before the stress studies are made because the blad­ der does not immediately return to its nor­ mal resting position after straining. ' H odgkinson CP, Doub HP, Kelly WT: Urethro­ cystograms: metallic bead chain technique, elin Obstet GYllecol 1 :668, 1 958.

After the metallic chain and contrast solution are instilled, the patient is usual ly prepared for upright radiographs. The ex­ amining room should be readied in ad­ vance so that the patients, who will be un­ comfortable, can be given immediate attention . The patient must be given kind reassurance and must be examined in pri­ vacy. Klawon' found that the fear of in­ voluntary voiding can be relieved by plac­ i ng a folded towel or disposable pad between the patient's thighs before the stress radiographs are taken. Thus pro­ tected, the patient willingly applies ful l pressure during the stress tudies. The IR size and centering point are the same as for other female cystourethro­ grams. (Fulther information on position­ ing of the lower urinary tract is provided on pp. 230 to 234 of this volume. ) ' Klawon Sister M M : Urethrocy tography and uri­ nary stress incontinence in women, Radiol Techn 39:353, 1 968.

238

VE N I PU N CTU RE A N D IV CONTRAST M E D IA ADM I N ISTRATION

.

Michael R. Bloyd

Advances in medical science and modern technology are creating tremendous changes and improvement in IV therapy, e pecially for tho e who perform diagnos­ tic imaging. As IV therapy has evolved over the years, radiologic technologists are being as igned roles in the patient­ focused, cost-effective collaborative team concept of modern health care. An esti­ mated 80% of patients in acute-care set­ tings require some type of IV medication. Administering medications accurately and safely is an important responsibil ity that must not be taken l ightly. I The principals of I V therapy include restoring and maintaining fl uid and elec­ trolyte balance, administering medication, transfusing blood, and deliveri ng par­ enteral nutrition solutions. The radiologic technologist may initiate venipuncture and administer medications by physician order for specific indications in certain types of IV therapy related to radio­ graphic procedures. 2

Professional and Legal Considerations Because of patient risk and legal liabilities, the radiologic technologist must follow profe ional recommendations, state regu­ lations, and institutional policies for the ad­ ministration of medications. The informa­ tion presented in this section i meant to be an introduction to IV therapy. Competency in this area requires the completion of a formal course of instruction with uper­ vi ed clinical practice and evaluation. ' Kowalczyk N, Donnett K: Integrated patient care for tire imaging professional, SI Louis, 1 996, Mosby. 2"fortorici M: Administration of imaging pharmaceu­ ticals, Philadelphia, 1 996, WB Saunders.

The American Society of Radiologic Technologists (ASRT) includes venipunc­ ture and IV medication administration i n the curriculum guidelines for the educa­ tional opportunities offered to technolo­ gists. Additional support for the adminis­ tration of medications and venipuncture as part of the technologist's scope of practice is found in the 1 987 Resolution No. 27 from the American College of Radiology. I Within specific established guidelines this resolution supports the injection of con­ trast materials and diagnostic levels of ra­ diopharmaceuticals by certified and/or li­ censed radiologic technologists. The ASRT Standards of Practice for Radiog­ raphy also support the administration of medication by technologists. Technologists who perform venipunc­ ture and contrast media administration must be knowledgeable about the specific state regulations and faci lity policies that govern these activities. Technologists also are responsible for professional decisions and actions in their practice. Competency in the skills of venipuncture and contrast media administration are based on cogni­ tive knowledge, proficiency in psychomo­ tor skills, positive affective values, and validation in a clinical setting.

Medications Medications for a specific procedure are prescribed by a physician, who is also re­ sponsible for obtaining informed consent for the procedure. A technologist may ad­ minister medications for radiographic procedures, which can require medica­ tions for sedation, pain management, con­ trast media administration, and emergen­ cies. 2 The technologist must have an extensive knowledge of all medications used in the radiology department. IV med­ ications are administered into the body via the vascular system; once administered, they cannot be retrieved. Therefore, be­ fore administering any medication, the technologist must know the medication's name, dosages, indications, contraindica­ tions, and possible adverse reactions. (Table 1 8- 1 ).

,:)_

Patient Education The manner in which the technologist ap­ proaches the patient can have a direct in­ fl uence on the patient's response to the procedure. Although the technologi t may consider the procedure routine, the patient may be total l y unfam i l i ar with it specifics. Apprehen ion experienced by the patient can cause vasoconstriction, making the venipuncture more difficult and more painful. I Careful explanation and a confident, understanding attitude can help the patient relax. The technologist must provide informa­ tion about the procedure in terms of the patient's understanding. The patient's questions must be answered in "layman 's" language. By explaining the detai ls of the procedure, the technologist can help al le­ viate fears and solicit cooperation from the patient. It is important to explain the steps in the procedure, its expected dura­ tion, and any l i mitations or restrictions as­ sociated with its performance. The patient may have heard an inaccurate "horror" story about the procedure from a neighbor or friend. Therefore the technologist may need to correct misconceptions and pro­ vide accurate information. For simple procedures the patient mu t be reassured that the procedure is rela­ tively straightforward and causes only slight discomfort. For more complex and longer procedures, the technologist must gain the patient's cooperation by provid­ ing appropriate, factual information and offering upport. The patient should never

be told that insertion of the needle used in venipuncture does not hurt. After all, a foreign object is going to be inserted through the patient's skin, which has a myriad of nerves that will be aggravated by insertion of a needle. The technologist must tell the truth and explain that the amount of pain experienced varies with each patient. 2 'IV therapy: skillbuilders, Springhouse, Penn, 1 99 1 , Springhouse. 2Hoeltke L: The complete textbook of phlebotomy, Albany, N Y, 1 994, Delmar.

'Tortorici M : Administration of imaging pharmaceu­ ticals, Philadelphia, 1 996, WB Saunders. 2 Kowalczyk N, Donnett K: Integrated patient care for the imaging professional, SI Louis, 1 996, Mosby.

239

TABLE 18-1 Common medications utilized in an imaging department

Brand Name

Generic Name

Indications

Action Binds with opiate recep-

Demerol

meperidine

Mild to moderate pain

How supplied

hydrochloride

Adjunct to anesthesia

tors of the CNS

Adverse Reactions Seizures, cardiac arrest. shock, respiratory depression

Tablets, syrup, injection

Morphine

morphine sulfate

Binds with opiate recep-

Severe pain

tors of the CNS

How supplied:

Bradycardia, shock, cardiac arrest. apnea, respiratory depression,

Tablets, syrup,

respiratory arrest

oral suspension, injection Versed

midazolam

How supplied:

hydrochloride

Preoperative sedation (to induce sleepiness or drowsiness and

Injection

re-

Unknown, thought to de-

ratory rate, nausea,

and subcortical levels

vomiting, hiccups, pain at injection site

lieve apprehension)

Valium

diazepam

Anxiety

Apnea, depressed respl-

press CNS at the limbic

Unknown, probably de-

Cardiovascular col-

How supplied:

presses the CNS at the

lapse, bradycardia,

Tablets, capsules,

limbic and subcortical

respiratory depression,

levels

acute withdrawal

oral solutions,

syndrome

Injections Noctec

chloral hydrate

Sedation

Unknown, sedative effects

Drowsiness, nightmares,

How supplied:

may be caused by its

hallucinations, nau-

Capsules, syrup,

primary metabolite

sea, vomiting, diarrhea

suppositories Glucagon

glucagon

Hypoglycemia

Raises blood glucose

Bronchospasm, hy-

How supplied:

level by promoting

potension, nausea,

Injection

catalytic depolymer-

vomiting

ization of hepatiC glycogen to glucose

Phenegran How supplied:

promethazine

Nausea, sedation

Competes with histamine

Dry mouth

for special receptors

hydrochloride

on effector cells.

Tablets, syrup, injection,

Prevents, but does not

suppositories

reverse histamine mediated responses

V lstarll How supplied:

hydroxyzine hydrochloride

Nausea and vomiting,

Unknown, actions may

Dry mouth, dyspnea,

anxiety, preoperative

be due to a suppres-

wheezing, chest

Tablets, syrup,

and postoperative

sion of activity In key

tightness

capsules,

adjunctive therapy

regions of the subcorti-

injection Benadryl How supplied:

cal area of the CNS diphenhydramine hydrochloride

Allergic reactions, sedation

Competes with histamine

Seizures, sleepiness, in-

for special receptors

somnia, incoordina-

on effector cells.

tion, restlessness, nau-

elixir, syrup,

Prevents, but does not

sea, vomiting, diarrhea

injection

reverse histamine me-

Tablets, capsules,

diated responses Narcan How supplied: Injection

naloxone hydrochloride

Known or suspected

Thought to displace previously administered

edema, ventricular

piratory depression

narcotic analgesiCS

fibrillation

from their receptors

Data from Nursing 200 1 drug handbook, Springhouse, Penn., 2001 , Springhouse Corporation.

240

Seizures, pulmonary

narcotic induced res-

Interactions May be incompatible when

Effects on Diagnostic Imaging Procedures None known

mixed in the same IV container

Contraindications

Patient Care Considerations

Patients with hypersensitivity

Give slowly by direct IV

to drug and in those who

injection. Oral dose is

have received MAO in-

less than half as effec-

hibitors within past

1 4 days

tive as parental dose. Compatible with most IV solutions

In combination with other de-

None known

Patients with hypersensitivity

Use with extreme cau-

pressants and narcotics use

to drug or conditions that

with extreme caution

would preclude adminis-

head injuries, In-

tration of IV oploids.

creased intracranial

tion in patients with

pressure or elderly CNS depressants may increase

Patients with hypersensitivity

None known

risk of apnea

Use cautiosuly in patients

to drug, acute angle-

with uncompensated

closure glaucoma, shock,

acute illness and in el-

coma or acute alcohol

derly. Before adminis-

intoxication

tering have emergency resuscitation equipment available

Other CNS depressants

May cause minor changes in EKG patterns

Patients with hypersensitivity to drug or soy protein,

Monitor respirations and before administering

shock, coma or acute al-

have emergency re-

cohol intoxication

suscitation equipment available

Alkaline solutions incompatible

None known

Patients with hepatic or re-

Note two strengths of

with aqueous solutions of

nal impairment. severe

oral liquid form. Double

chloral hydrate

cardiac disease or hyper-

check dose especially

sensitivity to drug

when administering to children

Inhibits glucagon induced insulin

None known

Patients with hypersensitivity

release

to drug or with pheochromocytoma

Arouse patient from coma as quickly as possible and give additional carbohydrates orally to prevent secondary hypoglycemic reactions

Increased effects when used with other CNS depressants

Discontinue drug

48

hours

before a myelogram because of high risk of

Patients with hypersensitivity to drug; intestinal obstruction, prostatic hyperplasias

Do not administer subcutaneously

seizures

Can increase CNS depression

None known

Hypersensitivity to drug, dur­ ing pregnancy, and in breast-feeding women

If used in conjunction with other CNS Medication observe for over sedation

Increased effects when used

None known

with other CNS depressants

Hypersensitivity to drug, dur­

Use with extreme cau­

ing acute asthmatic at­

tion in patients with

tacks, and in newborns or

angle-closure glau­

premature neonates and

coma, asthma, CO PO

breast-feeding women None reported

None known

Hypersensitivity to drug

Use cautiously in patients with cardiac irritability and opiate addiction

24 1

Patient Assessment

I nfection Control

The patient must be assessed before any medication is administered. Information about a history of allergy must be ob­ tained and documented. It is essential to determine whether the patient has any known al lergies to foods, medication , en­ vironmental agents, or other substances. Before venipuncture is performed, the technologist needs to be aware of the po­ tential for an al lergic reaction to the iodine tincture used in puncture site preparation or an adver e reaction to the medication being injected. Other assessment criteria include the patient's current medications. Knowledge of ome common medication actions can help the radiologic technologist evaluate changes in a patient's condition during a procedure. Certain diabetic medications interact adversely with contrast media. Therefore assessment of the i nteraction of medications must be evaluated prior to the performance of the procedure. During the physical evaluation, it is im­ portant to determine whether the patient has prev iously undergone surgical proce­ dure that might affect site selection for venipuncture, such as a mastectomy with resultant compromi ed lymph nodes and vascular abnormal ities. To determine the appropriate type and amount of medica­ tion to be administered, the physician re­ quires information about the patient's past and current di ease processes, such a hy­ perten ion and renal disease. Evaluation of the BUN level (average range: 1 0 to 20 mg/dl) and the creatinine level (average range: 0.05 to 1 .2 mg/dl) should be in­ cluded as assessment criteria.

Each time the body system is entered, the potential for contamination exists. ' Strict aseptic techniques and universal precau­ tions must always be used when medica­ tions are administered with a needle. 2 If a medication is injected incorrectly, a mi­ croorganism may enter the body and cause an infection or other complications. The Centers for Disease Control and Prevention have developed pecific guide­ li nes to prevent the transmission of infec­ tions during the preparation and adminis­ tration of medications. These guidelines are part of the Standard Precautions used by every health care facility and strict ad­ herence to the guidelines must be fol­ lowed by the technologist during the per­ formance of radiologic procedures. Studies using IV filters have shown a significant reduction in infusion phlebitis. Filters are devices located within the tub­ ing used for IV administration. Filters pre­ vent the injection of particulate and mi­ crobial matter into the circulatory system. The use of a fi lter for a bolus injection re­ duces the rate at which the medication can be injected. In addition, the viscosity of a medication may determine whether a fi lter is used and the rate of injection. Although a filter helps in reducing the possibility of bacteria being introduced into the blood, its use creates additional factors of risks versus benefits. The physician or health care facility should have policies to ad­ dress these issues.

NEEDLES AND SYRINGES The technologist assembles the proper sy­ ringe and needle for the planned i njection. The syringe may be glass or plastic. Plastic syringes are disposed of after only one use; glass syringes may be cleaned and must be steril ized before they are used again. The syringe has three parts: the tip, where the needle attaches to the syringe; the barrel, which includes the calibration marki ngs; and the plunger, which fit snugly i nside the barrel and allows the user to instill the medication (Fig. 1 8-82). The tip of the syringe for an rv injection has a locking device to hold the needle secure. The size of the syringe depends on the vol­ ume of material to be injected. The tech­ nologist should select the next-larger size of syringe than the volume de ired. This larger syringe assists in the accuracy of the dose by allowing the total amount of med­ ication to be drawn into one syringe.

A ll needles used in venipuncture are disposable and are used only once. During the preparation and administration of contrast media, the technologist uses several types of needles, including a hy­ podermic needle, a butterfly set, and an over-the-needle cannula (Fig. 1 8-83).

'Smith S, Duell: Clillica/ nursing skills basic 10 ad­ vanced skills, ed 4, Stanford, Conn., 1 996, Appleton & Lange. 2Adler AM, Carlton RR: Introduction to radiography and patiellt care, Philadelphia, 1 994, WB Saunders.

Fig. 1 8-82 Plastic disposable syringes.

242

Venipuncture Supplies and Equipment

Fig. 1 8-83 Types of needles: over-the-cannula needle, or angio­ catheter (bottom), a hypodermic needle (center). and metal butterfly needle (top).

Hypodermic needles vary in both gauge and length ( ee Fig. 1 8-83). Needle gauge refers to the diameter of the needle bore, with the gauge increasing as the diameter of the bore decrease . An 1 8-gauge needle is larger than a 22-gauge needle and de­ livers a given volume of fl uid more rapidly. The length of a needle is mea­ sured in inches and may vary from � inch ( used for intradermal injections) to 412 inches (used for intrathecal [spinal] injec­ tions). As a general rule, needles I to 1 1/2 inches long are most commonly used for IV injections. The needle has three parts: the hub, which is the part that attaches to the syringe; the cannula or shaft. which is the length of the needle; and the bevel, which is the slanted portion of the needle tip. Needles should be visually examined before and after use to determi ne whether any structural defects. such as non beveled points or bent shafts, are present. 1 Butterfly sets or angio catheters are preferable to a conventional hypodermic needle for most radiographic IV therapies. The butterfly set con i ts of a stainless­ steel needle with plastic appendages on either side and approximately 6 inches of plastic tubi ng that ends with a connector. The plastic appendages, often cal led wi ngs, aid in inserting the needle and sta­ bilization of the needle once venous pa­ tency has been confirmed. The over-the-needle cannula is a device in which, once the venipuncture is made, the catheter is sli pped off the needle into the vein and the steel needle is removed. This type of needle is recommended for long-term therapy or for rapid infusions. The choice of needle should be based on the assessment of the patient, institutional policy and the technologist's preference.

If the medication is supplied in a bottle or vial, the preparation procedure has sev­ eral variations. First, the solution must be evaluated for contamination. Then the protective cap is removed, with care taken not to contaminate the underlying surface. Containers have rubber stoppers through which a hypodermic needle can be in­ serted. If a single-dose vial is being used, and no contamination has occulTed, the rubber stopper requires no additional cleansing. M u l ti ple-dose vial stoppers must be cleaned with an alcohol wipe. For a closed system to be maintained, and reduce the chance of possible infec­ tion, a volume of air equal to the amount of desired fl uid must be injected into the bottle. The plunger of the syringe is pul led back to the level of the desired amount of medication. The shaft of the plunger must not be contaminated at any time during preparation of the medication. The needle

on the syringe is inserted into the rubber stopper, all the way to the hub of the nee­ dle. Then the vial is inverted by placing the end of the needle above the fluid level in the bottle (Fig. 1 8-84). Next a small amount of air is slowly injected into the vial above the level of the fl uid. This tech­ nique helps decrease air bubbles in the so­ lution. After the air has been injected, the vial and syringe are held inverted and per­ pendicular to a horizontal plane, and the tip of the needle is pulled below the fluid level. The desired amount of medication is aspirated into the syringe by pulling down on the plunger of the syringe. The above procedure may have to be repeated several times to get all of the medication out. I f air bubbles cling t o the syringe casing, the syringe may be lightly tapped to release them. A one-handed method is used to re­ cap the syringe (Fig. 1 8-85).

Fig. 1 8-84 Place the tip of the needle above the level of fluid before injection of air to decrease air bubbles in the solution.

MEDICATION PREPARATION Although TV offers the most i mmediate results in terms of effect, certain safety precautions must be followed. The tech­ nologist must identify the correct patient before medication is administered. During preparation and again before administra­ tion, the medication in the container also must be verified. 'Strasinger S. DiLorenzo M: Phlebotomy workbook for the multiskilled healthcare professional, Philadelphia, 1 996, FA Davis.

Fig. 1 8-85 When recapping a syringe. use a one-handed method.

243

Preparation of an infusion from a glass bottle or plastic bag begins with the iden­ tification and verification of the solution and its expiration date ( Fig. 1 8-86). The solution should not contain any visible particles. The tubing used for the infusion is determined by the method of injection and the type of container. Electronic infu­ sion devices require different tubing than gravity infusion devices. A glass container necessitates a vented tubing ( Fig. 1 8-87), whereas a plastic container requires a nonvented tubing ( Fig. 1 8-88).

To prepare for drip infusion of a med­ ication, the technologist removes the tub­ ing from the sterile package and closes the clamp (Fig. 1 8-89). Failure to close the clamp may result in loss of the vacuum in the solution container. The protective cov­ erings are removed from the port of the so­ lution and the tubing spike. Then the fill chamber of the tubing is squeezed, and the spike is inserted into the solution. The so­ l ution is then inverted and the chamber is released. The solution shoul d fi l l the chamber to the measurement line. The tub­ ing is primed by opening the clamp, which allows the solution to travel the length of the tubing, expelling any air. The tube is fi lled with solution, the clamp is closed, and the protective covering is secured. The solution is then ready for administration.

Fig. 1 8-86 Identify the correct solution and expiration date.

Fig. 1 8-88 Solutions in plastic bags require a nonvented tubing.

Procedure SITE SE LECTION Selection of an appropriate vein for venipuncture is critical. Finding the vein is sometimes difficult, and the most visi­ ble veins are not always the best choice . ' Technologists administer IV medication and contrast media v ia the venous system. Therefore, if a pulse is palpated during asessment for a puncture site, that vessel must not be used because it is an artery! The prime factors to consider in selecting a vein are ( I ) suitability of location, (2) condition of the vein, (3) purpose of the infusion, and (4) duration of therapy. The veins most often used in establishing IV access are found on the anterior forearm, posterior hand, radial aspect of the wrist, and antecubital space on the anterior sur­ face of the elbow ( Fig. 1 8-90). A general rule is to select the most dis­ tal site that can accept the desired-size needle and tolerate the injection rate and solution. Although the veins located at the antecubital space may be the most acces­ sible, largest, and easiest to puncture, they may not be the best choice. Because of their convenient location, these site may be overused and can become scarred or sclerotic. Antecubital accesses are located over an area of joint flexion; therefore any motion can di slodge the cannula and cause infiltration or result in mechanical phlebitis. A flexible IV catheter is the nee­ dle of choice for placement of a venous access in the antecubital space. The pa­ tient's arm should be immobil ized to in­ hibit the ability to flex the elbow. ' S teele J: Practical IV therapy, Springhouse, Penn., 1 988, Springhouse.

Fig. 1 8-87 A vented tubing is required for glass bottle containers.

244

Fig. 1 8-89 Close the tubing clamp before inserting the spike into a container of solution.

The condition of the vein must also be considered in the selection of an appropri­ ate puncture site. The selected vein must be able to tolerate the needed or desired can­ nula size. The vein should have resilience qualities and be anchored by surrounding supportive tissues to prevent rolling. Another consideration in vein selection is the rate of flow required for the proce­ dure and the viscosity and amount of med­ ication to be administered. Because the purpose of the infusion determines the rate of flow, the solution to be i nfused should be evaluated during the site selection process. Larger veins should be selected for infusions of large quantities or for rapid infusions. Large veins are also used for the infusion of highly viscous solutions or those that are irritating to vessels. I The expected duration of the therapy and the patient's comfort are other factors that must be considered in selecting a venipuncture site. If a prolonged course of therapy is anticipated, areas over flexion j oints should be avoided, and the dorsal surfaces of the upper l imbs should be carefu l ly exami ned. Venous access i n these locations w i l l provide more freedom and comfort to the patient. ' Adler AM, Carlton RR: Introduction to radiography alld patient care, Philadelphia, 1 994, WB Saunders.

Dorsal venous ������ arch

Superficial dorsal veins Posterior Right Hand Basilic vein

Anterior Right Forearm Basilic vein Median vein of forearm Median

1-....:u, :!IIIIl I/-- cubital vein

Basilic vein

Cephalic vein

Fig. 1 8-90 Veins easily accessible for venipuncture.

245

SITE PREPARATION The skin's surface must be prepared and cleaned. If the area selected for venipunc­ ture i hairy, the hair should be clipped to permit better cleansing of the kin and viualization of the vein . This will also make removal of the cannula less painful when the infusion is terminated. Shaving i not recommended. The skin is cleansed with an antiseptic, which should remain in contact with the skin for at least 30 sec­ onds. The preferred solution is iodine ti ncture I % to 2%. I sopropyl alcohol 70% i recommended if the patient is sensitive to iodine. The skin should be cleaned in a

circular motion from the center of the in­ jection site to approximately a 2-inch clr­ cle. Once the swab has been placed on the skin, it should not be lifted from the sur­ face until the cleansing process is com­ plete (Fig. 1 8-9 1 ). Many facil ities have a policy that pro­ vides the patient an opportunity to request a local anesthetic for IV infusion catheter placement. This technique reduces the pai n felt by the patient duri ng insertion of an angiocatheter or needle. The local anesthetic can be administered topically or by injection.

A facil ity's procedure for local anes­ thetic determines the pecific criteria for that i nstitution. Commonly accepted guidelines are as fol lows: First 0. 1 to 0.2 ml of I % lidocaine without epinephrine or sterile sal ine is prepared in a tuberculin or insulin syringe with a 23- to 25-gauge needle. The site for injection is selected and prepared. Then the anesthetic is in­ jected subcutaneously (beneath the skin, into the soft tis ue) or intradermally (im­ mediately under the skin in the dermal layer) at the venipuncture site. Topical anesthesia is achieved by applying 5 g of eutectic mi xture of local anesthetics cream and covering the area with an oc­ clusive dressing. Maximum effects are achieved in 45 to 60 minutes. The medication to be injected should already be prepared, and any tubing should be primed with the solution to pre­ vent injection of any air i nto the vascular system.

VENI PUNCTURE After the solution has been prepared, the site selected, and the type of syringe and needle to be used has been determined, the technologist is ready to perform the venipuncture. Techniques for venipuncture follow one of two cour es: ( I ) the direct, or one-step, entry method or (2) the indirect method. The direct, or one-step, method is per­ formed by thrusting the cannula through the skin and i nto the vein in one quick mo­ tion. The needle and cannula enter the skin directly over the vein. This technique is excellent as long as large veins are avai lable. ' The indirect method is a two­ step technique. First, the over-the-needle cannula is i nserted through the skin adja­ cent to or below the point where the vein is vi ible. The cannula is then advanced and maneuvered to pierce the vein. For the actual venipuncture procedure, the tech­ nologist washes the hands. The patient is identified. Next the technologist instructs the patient about the procedure. The tech­ nologist performs the fol lowing teps: I . The technologist puts on gloves and cleans the area in accordance with fa­ cil ity protocol (Fig. 1 8-92). ' Plumer AL: Principles and practice of illlravellOIlS therapy, ed 4, Boston, 1 987, Little, Brown.

Fig. 1 8·91 Prepare the site for venipuncture.

246

Fig. 1 8·92 Put on clean gloves.

Fig. 1 8·93 Apply the tourniquet 6 to 8 inches above the intended venipuncture site, with its free end directed superiorly.

2. A local anesthetic is administered ac­ cording to facility policy (optional). 3 . A tourniquet is placed 6 to 8 i nches above the intended site of puncture. The tourniquet should be tight enough to distend the vessels but not occlude them. The loose ends of the tourniquet should be placed away from the injec­ tion site to prevent contamination of the aseptic area (Fig. 1 8-93).

4. The technologist holds the patient's l i mb with the nondominant hand, us­ i ng that thumb to stabil ize and anchor the selected vein. The best method of accessing the vein-direct or indirect technique-is then determined. 5. Using the dominant hand, the technol­ ogist places the needle bevel up at a 45degree angle to the skin's surface. The bevel-up position produces less trauma to the skin and vein (Fig. 1 8-94).

Fig. 1 8-94 Stabilize the vein and enter the skin with the needle at a 45-degree angle.

Fig. 1 8-96 Anchor the needle with tape to secure placement.

Fig. 1 8-95 Release the tourniquet after the venous access has been obtained. Do not permit tourniquet to touch needle.

Fig. 1 8-97 Administer the medication.

6. The technologist uses a quick, sharp darting motion to enter the skin with the needle. Upon entering the kin, the technologist decreases the angle of the needle to I S degrees from the long axis of the vessel. Using an indi­ rect method, the technologist slowly proceeds with a downward motion on the hub or wings of the needle; raising the point of the needle, the technolo­ gist advances the needle parallel and then punctures the vein. The needle may have to be maneuvered sl ightly to facilitate actual venous puncture. If the direct method of access is used, the needle is placed on the skin di­ rectly over the vein, and entry into the vein is accomplished in one move­ ment of the needle through the skin and vein. Once the vein is entered, a backftow of blood may occur-this indicates a successful venipuncture. 7. Once the vein is punctured and a blood return is noted, the cannula is advanced cautiously up the lumen of the vessel for approximately % inch. 8. Release the tourniquet (Fig. 1 8-95 ). 9. I f a backftow of blood does not occur, verify venous access before injecting the medication. Aspiration of blood directly into the syringe of medication verifies placement before injecting. Another method of placement verifi­ cation is to attach a syringe of normal saline to the hub of the needle before aspirating for blood. The advantage of this method is that only saline, an iso­ tonic solution, is injected if the needle is not in place and extravasation oc­ curs. A successful venipuncture does not guarantee a successful injection. If a bolus injection is desired, the tourni­ quet may not be released until the in­ jection has been completed. If this technique i s used, the protocol must be i ncluded in the facility 's policies and procedures. 1 0. Anchor the needle with tape and a dressing, as required by policy (Fig. 1 8-96). Then administer the medica­ tion (Fig. 1 8-97) .

247

With experience, a technologist's fingers become sensitive to the sensation of the needle entering the vein-the resistance en­ countered as the needle penetrates the wall of the vein and the "pop" felt at the loss of re istance as the cannula enter the lumen. If both walls of the vein are punctured with a needle, the vessel develops a hematoma. The cannula should be removed immedi­ ately, and direct pressure should be applied to the puncture site. If a venipuncture at­ tempt is unsuccessful with an over-the­ needle cannula and the needle has been re­ moved from the cannula, the needle should not be reinserted into the catheter. Reinsert­ ing the needle into the cannula can sheer a portion of the catheter.

ADMINISTRATION The technologist should administer the medication and/or contrast medium at the established rate. During the injection process, the injection site should be ob­ served and palpated proximal to the punc­ ture for signs of infiltration. An infiltration, or extravasation, is a process whereby a fluid passes into the tissue instead of the vein. A patient may have a venous access that was established before the radiologic pro­ cedure. A careful assessment of site and medication compatibility must be per­ formed before the existing IV line can be used. (Compatability is the abi lity of one medication to mix with another.) Special precautions should be taken with a patient who is currently receiving cardiac, blood pressure, heparin, or diabetes medications. The physician, nur e, or pharmacist should be consulted before medication is adminis­ tered to such a patient. Verification must be obtained to ensure that the medication being infused through the established IV l i ne is compatible with the contrast medium to be administered. Before the contrast medium is injected, the infu ion should be stopped and the line should be fl ushed with normal saline through the port nearest the insertion site. The contrast medium is then administered, and the line is fl ushed again with normal saline. The amount of normal saline used depend on the facility's policies and procedures. Once

the contrast medium has been adminis­ tered, the r v infusion solution is restarted. Heparin or saline locks allow intermit­ tent injections through a port. The port is a smal l adapter with an access that is at­ tached to an IV catheter when more than one injection is anticipated. I As deter­ mined by procedure criteria, the cannula is flushed with heparin and saline to main­ tain patency during dormant periods. The patency (open, unobstructed flow) of the intermittent device is verified by aspirat­ ing blood and injecting normal saline with­ out infiltration. Then, the medication is ad­ ministered. Finally, the medication is flushed through the device with saline. Depending on protocols, the device may then be flushed with heparin or normal saline. After the medication has been adminis­ tered and the radiologic procedure has been completed, the venous access may be discontinued. The radiologic technolo­ gist should carefully remove any tape or protective dressing covering the puncture site. Using a 2 X 2-inch gauze pad at the injection site, the technologist then re­ moves the needle by pulling it straight from the vein. Direct pressure on the site is applied with the gauze only after the needle has been removed (Fig. 1 8-98). The technologist then puts the contami­ nated gloves, needles, and gauze in appro­ priate di posal containers (Fig. 1 8-99). ' Ehrlich R, McCloskey E D : Patient care i/l radiog­ raphy, ed 4, St Louis, 1 994, Mosby.

Fig. 1 8-98 Remove the IV access.

248

Fig. 1 8-99 Discard needles in puncture­ resistant containers.

Reactions and Complications Any medication has the potential to be harmful if it is not administered properly. ' Technologists mu t be aware of possible untoward medication reactions and be able to recognize and report signs and symp­ toms of side effects as they occur. 2 The technologist who prepares a medication should also perform the administration. Reactions can be mild, moderate, or se­ vere. M i ld reactions can include a sensa­ tion of warmth, a metallic taste, or sneez­ ing. Moderate reactions can manifest as nausea, vomiting, or itching. Finally, a se­ vere, or anaphylactic, reaction can cause a respiratory or cardiac crisis. The treatment for each category of reaction should be es­ tablished in the procedures of each facility or department. The role of the radiologic technologist in the case of a reaction should also be defined in the e documents. Competent professional standards of prac­ tice for the technologist include monitoring the patient's vital signs before, during, and after the injection of a contrast medium or certain types of medications. The specific monitoring criteria should be established by institutional policy. Therefore, if an un­ toward event should occur, responding per­ sonnel will have access to important infor­ mation about the patient's condition before the event occurred. Every health care provider should be fa­ miliar with emergency procedures in the work environment. Emergency crash carts contain many medications and pieces of equipment that require regular review. Proficiency in the operation of equipment and the admini stration of medications must be maintained. The technologist must have the knowledge, proficiency, and confidence to manage crisis situations. ' Kowalczyk N, Donnett K: Integrated patient care for the imaging professiollal, St Louis, 1 996, Mosby. 2Adler A M , Carlton RR: IllIrodllctioll to radiography and patielll care, Phi ladelphia, 1 994, WB Saunders.

Infiltration is another complication as­ sociated with the administration of con­ trast media or medications. This complica­ tion occurs when the medication or contrast material enters the soft tissue in­ stead of the vei n . ' Signs of infiltration are swelling, redness, burning, and pain. The most common cause of extravasation is needle displacement. If infiltration occurs, the procedure should be stopped immedi­ ately and the venous access discontinued. The physician must be notified, and spe­ cific treatment instructions must be re­ quested. Common therapies for infiltration are ( I ) the application of ice if less than 30 minutes have passed since the infiltration occurred or (2) the application of warm, wet compresses if the i nfiltration occurred more than 30 minutes previously. '

Docu mentation In the administration of any medication, the radiologic technologist should always observe five "rights of medication admin­ istration": • The right patient • The right medication • The right route The right amount • The right lime The right patient must receive the med­ ication. The identity of the patient must be confirmed before the medication is ad­ ministered. Methods of patient identifica­ tion include checking the patient's wrist­ band and having the patient to restate his or her name. If the patient is unable to speak, seek assistance in identifying the patient from a family member or signifi­ cant other. Ensuring that the right medica­ tion is administered requires that the name of the medication be verified at least three times: during the selection process, during the preparation, and immediately before the administration. The amount of med­ ication is determined by the physician or by departmental protocols. The right route, right amount, and right time are de­ termined by the physician, the type of medication, and the procedure. •

Documentation of the five rights of med­ ication administration is to be included in every patient's permanent medical record. I n addition to these five rights, the documenta­ tion should include the size, type, and loca­ tion of the needle; the number of venipunc­ ture attempts; and the identity of the health care personnel who performed the proce­ dure. Information about how the patient re­ sponded to the procedure should also be documented. The following is an example of correct documentation techniques for a technologist performing venipuncture and administering a medication: 4- 1 5-99 at 0900 a venous access on Mr. John Q Public was performed using an 1 8-gauge an­ giocatheter. The access was established in the dorsum of the left hand after one attempt. Then 1 00 ml of (the specific name of the medica­ tion) was administered by IV push via the ac­ cess. The patient tolerated the injection proce­ dure and medication without complaints of pain or discomfort and with no unexpected side effects. (Sandy R. Ray, R .T.)

The objective of medication therapy and administration is to provide the maximum benefit to the patient with the minimum harm. Medications are intended to help maintain health, treat or prevent disease, re­ lieve symptoms, alter body processes, and diagnose disease. Unfortunately, all med­ ications are not ideal in their effects on the human body. It is important that health care providers understand their role and respon­ sibilities in the administration of medica­ tions. Because the medications used by the radiologic technologist are less than perfect, caution for the patient's well-being and skill in the administration of the medications is a priority. Patients have the right to expect that the personnel who administer medica­ tions are informed about dosages, actions, indications, adverse reactions, interactions, contraindications, and special considera­ tions. Education, training, licensing, and experience are critical in establishing com­ petency in this area of practice.

'Tortorici M: Administration of imaging pharmaceu­ ticals, Philadelphia, 1 996, WB Saunders.

249

19

OUTLINE

SUM MARY OF PROJ E CTIONS

P ROJECTIONS, POSITIONS, & M ETHODS Anatomy

Projection

Hysterosalpingography

AP. lateral, axial, oblique

267

Abdomen: pelvimetry

AP

268

Abdomen: pelvimetry

Lateral

270

Seminal ducts

AP or AP oblique

Page

260

Essential

Position

Method

COLCHER-SUSSMAN R or L

COLCHER-SUSSMAN

Icons In the Essential column indicate projections frequently performed in the United States and Canada. Students should be competent In these projections

i "�.:.

ANATO MY

Female Reproductive System The female reproductive system consists of an internal and an external group of or­ gans, with the two groups connected by the vaginal canal. This chapter does not address the anatomy of the external geni­ talia because those structures do not re­ quire radiographic demonstration. The in­ ternal genital organs consist of the female gonads, or ovaries, which are two glandu­ lar bodies homologous to the male testes, and a system of canals made up of the uterine tubes, uterus, and vagina.

OVARIES The two ovaries are small , glandular or­ gans with an internal secretion that con­ trols the menstrual cycle and an external secretion containing the ova, or female re­ productive cells (Fig. 1 9- 1 ). Each ovary is shaped approximately like an almond. The

ovaries l ie one on each side, inferior and posterior to the uterine tube and near the lateral wall of the pelvis. They are attached to the posterior surface of the broad liga­ ment of the uterus by the mesovarium. The ovary has a core of vascular tissue, the medulla, and an outer portion of glan­ dular tissue termed the cortex. The cortex contains ovarian follicles in all stages of development, and each follicle contains one ovum. A fully developed ovarian fol­ l icle is referred to as a graafianfollicle. As the minute ovum matures, the size of the fol licle and its fluid content increase so that the wall of the fol licle's sac ap­ proaches the surface of the ovary and in time ruptures, liberating the ovum and fol­ licular fl uid into the peritoneal cavity. Extrusion of an ovum by the rupture of a fol licle is called ovulation and usually oc­ curs one time during the menstrual cycle. Once the ovum is in the pelvic cavity, it is drawn toward the uterine tube.

Primary ovarian follicles

UTERINE TUBES The two uterine tubes, or fallopian tubes, arise from the lateral angle of the uterus, pass laterally above the ovaries, and open into the peritoneal cavity. These tubes col­ lect ova released by the ovaries and convey the cells to the uterine cavity. Each tube is 3 to 5 inches (7.6 to 1 3 cm) in length (Fig. 1 9-2) and has a small diameter at its uter­ ine end, which opens into the cavity of the uterus by a minute orifice. The tube itself is divided into three parts: the isthmus, the ampulla, and the infundibulum. The isth­ mus is a short segment near the uterus. The ampulla makes up most of the tube and is wider than the isthmus. The terminal and lateral portion of the tube is the infundibu­ lum and is flared in appearance. The in­ fundibulum ends in a series of irregular prolonged processes called fimbriae. One of the fimbriae is attached either to or near the ovary. The mucosal lining of the uterine tube contains hairlike projections called cilia. The lining is arranged in folds that in­ crease in number and complexity as they approach the fimbriated extremity of the tube. The cilia draw the ovum into the tube, which then conveys it to the uterine cavity by peristaltic movements. The pas­ sage of the ovum through the tube re­ quires several days. Fertilization of the cel l occurs in the outer part of the tube, and the fertilized ovum then migrates to the uterus for implantation.

Graafian follicle Fig. 1 9- 1 Section of an ovary.

;;;���j����iiiA!i!���

�

Cavity of uterus

Ampulla

Fimbriae Fig. 1 9-2 Section of left uterine tube.

253

UTERUS The uterus is a pear-shaped, muscular or­ gan (Figs. 1 9-3 and 1 9-4). Its primary functions are to receive and retain the fer­ til ized ovum until development of the fe­ tus is complete and, when the fetus is ma­ ture, to expel it during birth. The uterus consists of four parts: the fundus, body, isthmus, and cervix. The fundus is the bluntly rounded superior most portion of the uterus. The body nar­ rows from the fundus to the isthmus and is the point of attachment for the ligaments that secure the uteru within the pelvis. The isthmus (superior part of the cervix), a constricted area between the body and the cervix, is approximately Y2 inch ( 1 .3 cm) long. The cervix is the cylindric vaginal end of the uterus and is approximately I inch (2.5 cm) long. The vagina is attached around the circumference of the cervix.

The nulliparous uterus ( i .e., the uterus of a woman who has not given birth) is approximately 3 inches (7.6 cm) in length, almost half of which represents the length of the cervix. The cervix is approximately % inch ( 1 .9 cm) in diameter. During preg­ nancy the body of the uterus gradually ex­ pands into the abdominal cavity, reaching the epigastric region in the eighth month. Following parturition, the organ shrinks to almost its original size but undergoes characteristic changes in shape. The uterus is situated in the central part of the pelvic cavity, where it l ies posterior and superior to the urinary bladder and anterior to the rectal ampulla. The long axis, which is slightly concave anteriorly, is directed i nferiorly and posteriorly at a near right angle to the axis of the vaginal canal into which the lower end of the cervix projects.

VAGINA The vagina is a muscular structure with walls and a canal lying posterior to the urinary bladder and urethra and anterior to the rectum. Averaging about 3 inches (7.6 cm) in length, the vagina extends inferi­ orly and anteriorly from the uterus to the exterior. The mucosa of the vagina is con­ tinuous with that of the uterus. The space between the labia minora is known as the vaginal vestibule and contains the vaginal orifice and the urethral orifice.

Fundus

Round ligament

Uterine tube

Fig. 1 9-3 Superoposterior view of uterus, ovaries, and uterine tubes.

Uterine tube

Uterine tube (cut)

rinary bladder

Fig. 1 9-4 Sagittal section showing relation of internal genitalia to surrounding structures. 254

The cavity of the body of the uterus, or the uterine cavity proper, is triangular in shape when viewed in the frontal plane. The canal of the cervix is di lated in the center and constricted at each extremity. The proximal end of the canal is continu­ ous with the canal of the isthmus. The dis­ tal orifice is called the uterine ostium. The mucosal l ining of the uterine cavity is called the endometrium. Thi lining un­ dergoes cyclic changes, called the men­ strual cycle, at about 4-week intervals from puberty to menopause. During each premenstrual period the endometrium is prepared for the implantation and nutri­ tion of the fertilized ovum. If fertilization has not occurred, the menstrual flow of blood and necrosed particles of uterine muco a ensues.

FETAL DEVElOPMENT During the implantation process, the fertil­ ized ovum, called a zygote, is passed from the uterine tube into the uterine cavity, where it adheres to and becomes embed­ ded in the uterine l ining. About 2 weeks after fertilization of the ovum, the embryo begins to appear. Nine weeks after fertil­ ization the embryo becomes a fetus and as­ sumes a human appearance (Fig. 1 9-5). During the first 2 weeks of embryonic development, the growing fertilized ovum is pri marily concerned with the establ ish­ ment of its nutritive and protective cover­ ing, the chorion and the amnion. As the chorion develops, it forms ( I ) the outer layer of the protective membranes enclos­ ing the embryo and (2) the embryonic portion of the placenta, by which the um­ bil ical cord is attached to the mother's uteru and through which food is supplied to and waste is removed from the fetus. The amnion, often refelTed to as the "bag of water" by the laity, forms the inner layer of the fetal membrane and contains amniotic fluid in which the fetus floats. Following the birth, the uterine li ning is expelled with the fetal membranes and the placenta, constituting the afterbirth. A new endometrium is then regenerated. The fertilized ovum usually becomes embedded near the fundus of the uterine cavity, most frequently on the anterior or posterior wal l . I mplantation occasionally occurs so low, however, that the fully de­ veloped placenta encroaches on or ob­ structs the cervical canal. This condition results in premature separation of the pla­ centa, termed placenta previa ( Fig. 1 9-6).

Placenta

Urinary bladder

Fig. 1 9-5 Sagittal section showing fetus of about 7 months of age.

Lateral

Central

Posterior

Fig. 1 9-6 Schematic drawings of several placental sites in low implantation.

255

Male Reproductive System The male genital system consists of the fol lowi ng: a pair of male gonads, the testes, which produce spermatozoa; two excretory channels, the ductus deferens, or vas deferens; the prostate; the ejacula­ tory ducts; the seminal vesicles; and a pair of bulbourethral glands that produce e­ cretions which are added to the secretions of the testes and ductal mucosa to consti­ tute the final product of seminal fl uid. The penis, the scrotum, and the structures en­ closed by the scrotal sac (testes, epi­ didymides, spermatic cords, and part of the ductus deferens) are the external geni­ tal organs.

SEMINAL VESICLES

EJACULATORY DUCTS

The two seminal vesicles are sacculated structures about 2 inches (5 cm) in length (Fig. J 9-9). They are situated obliquely on the lateroposterior surface of the bladder, where, from the level of the ureterocystic junction, each slants inferiorly and medi­ ally to the base of the prostate. Each am­ pulla of the ductus deferens l ies along the medial border of the seminal vesicle to form the ejaculatory duct.

The ejaculatory ducts are formed by the union of the ductus deferens and the duct of the seminal vesicle. The ejaculatory ducts average about Y2 inch ( 1 .3 cm) in length and originate behind the neck of the bladder. The two ducts enter the base of the prostate and, passing obliquely in­ feriorly through the substance of the gland, open into the prostatic urethra at the lateral margins of the prostatic utricle. These ducts eject sperm into the urethra before ejaculation.

TESTES The testes are ovoid bodies averagi ng 1 1/2 i nches ( 3 . 8 cm) i n length and about I inch ( 2 . 5 cm) in both width and depth (Fig. 1 9-7). Each testis is divided i nto 200 to 300 partial compartments that constitute the glandular substance of the testis. Each compartment houses one or more convoluted, germ ce l l-producing tubules. These tubules in turn converge and unite to form 1 5 to 20 ductules that emerge from the testis to enter the head of the epididymis. The epididymis is an oblong structure that is attached to the superior and latero­ posterior aspects of the testis. The duc­ tules leading out of the testis enter the head of the epididymis to become contin­ uous with the coiled and convoluted duc­ tules that make up this structure. As the ductules pass i nferiorly, they progres­ sively unite to form the main duct, which is continuous with the ductus deferens.

DUCTUS DEFE RENS The ductus deferens is 1 6 to 1 8 inches (40 to 45 cm) long, and extends from the tail of the epididymis to the posteroinferior surface of the urinary bladder. Only its first part is convoluted. From its beginning the ductus deferens ascends along the me­ dial side of the epididymis on the poste­ rior surface of the testis to join the other constituents of the spermatic cord, with which it emerges from the scrotal sac and passes into the pelvic cavity through the i nguinal canal ( Fig. 1 9-8). Near its termi­ nation the duct expands into an ampulla for the storage of seminal fl uid and then ends by uniting with the duct of the semi­ nal vesicle. 256

Testicular artery Ductus deferens

--"rt-- Head of epididymis Epididymis

Testis

Fig. 1 9-7 Frontal section of testes and ductus deferens.

Sacrum --+f4.2f--r

[llpn�wn--7ff- Bladder _�""'H- Pubis

Rectum --+---->,,>,----;r�<'<_ Prostate

Urethra

Fig. 1 9-8 Sagittal section showing male genital system.

PROSTATE The prostate, an accessory genital organ, is a somewhat cone-shaped organ and aver­ aging I � inches (3.2 cm) in length. The prostate encircles the proximal portion of the male urethra and, extending from the bladder neck to the pelvic floor, lies in front of the rectal ampulla approximately I inch (2.5 cm) posterior to the lower two thirds of the pubic symphysis (see Fig. 1 9-9). The prostate is composed of muscular and glan­ dular ti sue. The ducts of the prostate open into the prostatic portion of the urethra.

Because of advances in diagnostic ul­ trasound imaging, radiographic examina­ tions of the male reproductive system are performed less often than in the past. The prostate can be ultrason ical ly i maged through the urine-filled bladder or using a special rectal transducer. The semi nal ducts can be imaged when the rectum is fi l led with an ultrasound gel and a special rectal transducer is used. Testicular ultra­ sonic scans are performed to evaluate a palpable mass or an enlarged testis and to check for metastasis. The vast majority of the testicular scans are performed because of a palpable mass or an enlarged testis.

Urinary bladder Ductus deferens

B A

Prostate gland

_::;:.-...,..- Seminal vesicle duct

u.ilfS-7-+-+-- Ejaculatory duct

Penis

Fig. 1 9-9 A, Sagittal section through male pelvis. B, Posterior view of male reproductive organs.

257

SUMMARY OF ANATOMY* Female reproductive system

ovaries uterine tubes uterus vagina Ovaries

ova mesovarium medulla cortex ovarian follicles graafian follicle ovulation Uterine tubes (Fallopian tubes)

isthmus ampulla infundibulum fimbriae cilia

Uterus

fundus body isthmus cervix uterine ostium endometrium Vagina

mucosa vaginal vestibule vaginal orifice urethral orifice Fetal development

zygote embryo fetus placenta

Male reproductive system

testes ductus deferens (vas deferens) prostate ejaculatory ducts seminal vesicles bulbourethral glands penis scrotum Testes

epididymis Ductus deferens

ampulla

'See Addendum at the end of the volume for a summary of the changes in the anatomic terms that were introduced in the 9th edition.

258

SUMMARY OF PATHOLOGY Condition

Definition

Adhesion

Union of two surfaces that are normally separate

Endometrial Polyp

Growth or mass protruding from the endometrium

Fallopian Tube Obstruction

Condition preventing normal flow through the fallopian tube

Fistula

Abnormal connection between two internal organs or between an organ and the body surface

Tumor

New tissue growth where cell proliferation is uncontrolled

Dermoid Cyst

Tumor of the ovary filled with sebaceous material and hair

Uterine Fibroid

Smooth-muscle tumor of the uterus

259

Female Radiography NON PREGNANT PATIENT Radiologic investigation of the nonpreg­ nant uterus, accessory organs, and vagina are denoted by the terms hysterosalpin­ gography, pelvic pneumography, and vaginography. Each procedure requires the use of a contrast medium and should be carried out under aseptic conditions. Hysterosalpingography i nvolves the intro­ duction of a radiopaque contrast medium through a uterine cannula. The procedure is performed to determine the size, shape, and position of the uterus and uterine tubes; to delineate lesions such as polyps, submucous tumor masses, or fistulous tracts; and to investigate the patency of the uterine tubes in patients who have been unable to conceive (Fig. 1 9- 1 0) . Pelvic pneumography, which requires the introduction of a gaseous contrast medium directly into the peritoneal cavity, is now rarely performed because of the de­ velopment of ultrasonic techniques for evaluating the pelvic cavity. Vaginography is performed to investigate congenital ab­ normalities, vaginal fistulae, and other pathologic conditions involving the vagina. Contrast media

Various opaque media are used in exami­ nations of the female genital passages. The water-soluble contrast media em­ ployed for intravenous urography are widely used for hysterosalpingography and vaginography.

Appointment date and care of patient

Gynecologic exami nations should be scheduled approximately 1 0 days after the onset of menstruation. This is the i nterval during which the endometrium is least congested. More importantly, because this time interval is a few days before ovula­ tion normally occurs, there is little danger of irradiating a recently fertilized ovum. The relatively minor instrumentation required for the introduction of contrast medium in these examinations normally necessitates neither hospital ization nor premedication. Some patients experience unpleasant but transitory aftereffects . Therefore the radiology department should have facilities for an outpatient to rest in the recumbent position before re­ turning home. The patient is requested to completely empty her bladder immediately before the exami nation. This procedure prevents pressure displacement of and superimpo­ sition of the bladder on the pelvic geni­ talia. In addition, the patient's vagina is ir­ rigated just before the examination. At this time the patient should be given the necessary supplies and instructed to cleanse the perineal region.

Radiation protection

To deliver the least possible amount of ra­ diation to the gonads, the radiologist retricts fl uoroscopy and i maging to the minimum required for a satisfactory ex­ amination. Hysterosalpingography

Hysterosalpingography is performed by a physician with spot radiographs made while the patient is in the supine position on a fl uoroscopic table. The examination may also be performed by the physician with conventional radiographs obtained using an overhead tube. When fluo­ roscopy is used, spot radiographs may be the only i mages obtained. Preparing the patient for the examination involves the following steps: • After irrigation of the vaginal canal, complete emptying of the bladder, and perineal cleansing, place the patient on the examining table. Adjust the patient in the lithotomy po­ sition, with the knees flexed over leg rests. When a combination table is used, ad­ just the patient's position to permit the IRs to be centered to a point 2 i nches (5 cm) proxi mal to the pubic symphysis; 24 X 30 cm IRs are used for all studies and are placed lengthwise. •

•

Preparation of intestinal tract

Preparation of the intestinal tract for any of these examinations usually consists of the fol lowing: I . A non-gas-forming laxative is adminis­ tered on the preceding evening if the patient is constipated. 2. Before reporting for the examination, the patient receives cleansing enemas until the return flow is clear. 3 . The meal preceding the examination is withheld.

Fig. 1 9- 1 0 Hysterosalpingography reveals bilateral hydrosalpinx of uterine tubes (arrows). The contrast-filled uterine cavity is normal (arrowheads).

260

After inspection of the preliminary ra­ diograph and with a vaginal speculum i n position, the physician inserts a uterine cannula through the cervical canal, fits the attached rubber plug, or acorn, firml y against the external cervical 0 , applies counterpressure with a tenaculum to pre­ vent reflux of the contrast medium, and withdraws the speculum unless it is radi­ olucent. An opaque or a gaseous contrast medium may then be i njected via the can­ nula into the uterine cavity. The contrast material flows through patent uterine tubes and "spills" into the peritoneal cav­ ity (Figs. 1 9- 1 1 to 1 9- 1 3). Patency of the uterine tubes can be determined by trans­ uterine gas insufflation (Rubin test), but the length, position, and course of the ducts can be demonstrated only by opaci­ fying the lumina. The free-flowing, iodi nated organic contrast agents are usuall y injected at room temperature. These agents pass through patent uterine tubes quickly, and the resultant peritoneal spil l is absorbed and eliminated by way of the urinary sys­ tem, usually within 2 hours or less. The contrast medium may be i njected with a pressometer or a syringe. I n tra­ uterine pressure is maintained for the ra­ diographjc studies by closing the cannu­ lar valve. In the absence of fl uoroscopy the contrast medium is i ntroduced in two to four fractional doses so that excessive peritoneal spil lage does not occur. Each fractional dose is fol lowed by a radio­ graphic study to determi ne whether the fil li ng is adequate as shown by the peri­ toneal spi l l . The radiographs may consist o f no more than a single AP projection taken at the end of each fractional injection. Other projections (oblique, axial, and lateral) are taken as indicated.

Uterine tube

Normol contrast 'spill" into peritoneal cavity

Body of uterus

Speculum Fig. 1 9- 1 1 Hysterosalpingogram, AP projection, showing normal uterus and uterine tubes.

Fig. 1 9- 1 2 Hysterosalpingogram, AP projection, showing submucous fibroid occupying entire uterine cavity (arrowheads).

EVALUATION CRITERIA

The following should be clearly demon­ strated: • The pelvic region 2 i nches (5 cm) above the pubic symphysis centered on the radiograph • All contrast media visible, i ncluding any "spill" areas • A short scale of contrast on radiographs

Fig. 1 9- 1 3 Hysterosalpingogram, AP projection, revealing uterine cavity to be bicornate in outline.

261

Pelvic pneumography

L-_---- Ovary

� ---

Uterine tube

Pelvic pneumography, gynecography, and pangynecography are the terms used to denote radiologic examinations of the fe­ male pelvic organs by means of intraperi­ toneal gas i nsufflation (Fig. 1 9- 1 4). These procedures have essentially been replaced by ultrasonography and other diagnostic techniques. ( Pelvic pneumography is de­ scribed in volume 3 of the fourth edition of this atlas.)

Round ligament Vaginography

�--- Gaseous contrast medium

::;::====�� Urinary bladder

Fig. 1 9- 1 4 Normal pelvic pneumogram. (See Fig. 1 9-3 for correlation with radiograph.)

Vaginography is used in the investigation of congenital malformations and patho­ logic conditions such as vesicovagi nal and enterovagi nal fistulas. The examination is performed by introducing a contrast medium into the vaginal canal . Lambie, Rubin, and Dann' recommended the use of a thin barium sulfate mixture for the in­ vestigation of fistulous communications with the intestine. At the end of the exam­ ination the patient is instructed to expel as much of the barium mixture as possible, and the canal is then cleansed by vaginal irrigation. For the i nvestigation of other conditions, Coe2 advocated the use of an iodinated organic compound. A rectal retention tube is employed for the introduction of the contrast medium so that the moderately inflated balloon can be used to prevent reflux. I n one technique, the physician inserts only the tip of the tube into the vaginal orifice. The patient is then requested to extend the thighs and to hold them in close approximation to keep the in­ flated balloon pressed firmly against the vaginal entrance. In another technique, the tube is inserted far enough to place the de­ flated balloon within the distal end of the vagina, and the balloon is then inflated un­ der fluoroscopic observation. The barium mixture is introduced with the usual enema equipment. The water-soluble medium is injected with a syringe. Vaginography is performed on a combi­ nation fluoroscopic-radiographic table. The contrast medium is i njected under flu­ oroscopic control, and spot radiographs are exposed as indicated during the fi l ling (Fig. 1 9- 1 5). ' Lambie RW, Rubin S , Dann D S : Demonstration of fistulas by vaginography, AJR 90:7 1 7, 1 963 . 'Coe FO: Vaginography, AJR 90:72 1 , 1 963.

Fig. 1 9- 1 5 Vaginogram, spot rodiograph, PA oblique projection, LAO position. Sigmoid fis­ tula and two ileum fistulas are shown. 262

The radiographs i n Figs. 1 9- \ 6, \ 9- 1 7, and 1 9- 1 8 were taken with the central ray directed perpendicular to the midpoint of the IR. For localized studies, the central ray is centered at the level of the superior border of the pubic symphysis. I n each examination the radiographic projections required are determ ined by the radiologist accordi ng to the fluoroscopic findings. Low rectovaginal fistulas are best shown i n the lateral projection, and fistulous communications with the sig­ moid and/or i leum are best shown in oblique projections. EVALUATION CRITERIA

The following should be clearly demon­ strated: • Superior border of the pubic symphysis centered on the radiograph • Any fistulas in their entirety • Optimal density and contrast to visual­ ize the vagina and any fistula • Pelvis on oblique projections not super­ i mposed by the proximal thigh • Superimposed hips and femora in the lateral i mage

Fig. 1 9- 1 6 Vaginogram, AP projection, showing small fistulous tract (arrow) projecting lat­ erally from apex of vagina and ending in abscess.

Fig. 1 9- 1 7 Vaginogram, AP oblique projection, RPO position. Fistulas to ileum and sigmoid are shown.

Fig. 1 9- 1 8 Vaginogram, lateral projection, showing low rectovagi­ nal fistula. 263

264

PREGNANT PATIENT

Radiation protection

Care of patient

Because ultrasonography provides visual­ ization of the fetus and placenta with no apparent risk to the patient or fetus, it has become the preferred diagnostic tool for examination of the pregnant female. I n some situations, however, certain radio­ logic examinations are sti l l indicated: Fetography is the demonstration of the fe­ tus in utero. If possible, this examination technique is avoided until after the eigh­ teenth week of gestation because of the danger of radiation-induced fetal malfor­ mations. Fetography is employed to detect su pected abnormalities of development, to confirm su pected fetal death, to deter­ mine the presentation and position of the fetus, and to determine whether the preg­ nancy is single or multiple. Radiographic pelvimetry and fetal cephalometry are performed to demon­ strate the architecture of the maternal pelvis and to compare the size of the fetal head with the size of the maternal bony pelvic outlet. This purpose of the proce­ dure is to determine whether the pel vic di­ ameters are adequate for normal parturi­ tion or whether cesarean section i s necessary for the delivery. Although many techniques and combinations of tech­ niques are employed in radi ographic pelvimetry, only a few of the body posi­ tions and pertinent technical factors are included in this text. Placentography is the radiographic ex­ ami nation in which the walls of the uterus are investigated to locate the placenta in cases of suspected placenta previa. At one time radiographs were the only means available to detect such conditions. With advances in technology and the concern over the dose of radiation received by the fetus, diagnostic ultrasound (see Chapter 37) has become a valuable diagnostic tool for placenta localization.

Radiologic examinations of pregnant pa­ tients are performed only when required information can be obtained in no other way. In addition to the danger of genetic changes that may result from reproductive cell irradiation is the danger of radiation­ induced malformations of the developing fetus. Whenever possible, radiation for any purpose is avoided during pregnancy, especially during the first trimester of ges­ tation. If examination of the abdomino­ pelvic region is necessary, it is restricted to the absolute minimum number of radi­ ographs. The radiographer'S responsibility is to carry out the work carefully and thoughtfully so that repeat exposures are not necessary.

The patient who is in labor or is bleeding because of a placental separation must be treated as an emergency and must be under constant observation by qualified personnel.

Preparation of patient

Although it is desirable to clear the l arge bowel of gas and fecal material with a cleansing enema shortly before any radio­ logic examination, preliminary prepara­ tion depends on the condition of the pa­ tient. U nder no circu mstances is a cleansing enema administered without the express permission of the attending physi­ cian. The patient should completel y empty the bladder i mmediately before the examination. This is particularly i mpor­ tant when the upright position is used be­ cause the fil led bladder prevents the fetus from descending to the most dependent portion of the uterine cavity.

Respiration

A change in the oxygen content of the ma­ ternal blood causes the fetus to react quickly by movement. Just before suspen­ sion of respiration for the exposure, the mother's blood should be hyperaerated by having her i nhale deeply several times and then suspend respiration during the i nspi­ ration phase. Fetography

Fetography has generally been replaced by sonography and therefore is not fully described in this edition. A more complete description of this technique is provided in the seventh edition or even earlier edi­ tions of this atlas. AP or PA and lateral projections are ob­ tained to demonstrate the maternal pelvis and developing fetus (Figs. 1 9- 1 9 to 1 9-2 1 ). The following steps are observed: • Whenever possible, situate the patient in a prone position to place the fetus closer to the I R . To accomplish this, place supports under the chest, upper abdomen, and femora (Fig. 1 9-22) . • I f the prone position cannot b e used, place the patient supine on the radio­ graphic table with a support under the knees to relieve back strain. • For the lateral projection, have the patient lie on her side and support the abdomen to be parallel to the table if needed. • Center the perpendicular central ray to the abdomen.

Fig. 1 9- 1 9 Fetography. PA projection. Twin pregnancy showing two fetal heads (arrows and arrowheads),

Fig. 1 9-20 Fetography. AP projection. showing one fetus,

R,

Fig. 1 9-21 Fetography. lateral projection, showing triplet pregnancy,

Fig. 1 9-22 Fetography, prone position, showing support under pa­ tient's legs and thorax,

265

Radiographic pelvimetry and cephalometry

Mo t pelvimetry techniques have been re­ placed by sonography. Thus the Ball and Thoms methods have been deleted from this edition. (See the eventh or earlier edition of this atlas for descriptions of these method s . ) However, obtai nable pelvic measurements and the Colcher­ Sussman method of pelvimetry are de­ scri bed here.

The pelvi metry requires a knowledge of pelvic anatomy. The entrance to the true pelvis, called the superior strait or pelvic inlet, is bounded by the sacral promontory, the linea terminalis, and the crests of the pubic bones and symphysis. The internal anteroposterior diameter of the inlet i measured from the center of the sacral promontory to the superoposte­ rior margin of the pubic symphysis and is called the internal conjugate diameter or the conjugata vera. Other internal diame­ ters of the pelvic cavity are shown in the accompanying ill ustrations (Figs. 1 9-23 and 1 9-24).

Fig. 1 9-23 Pelvis seen from above. A, Anteroposterior diameter of the inlet. B, Transverse diameter of inlet. C, Posterior sagittal di­ ameter of inlet. D, Interspinous or transverse diameter of mid­ plane. E Widest transverse diameter of outlet.

266

The external conjugate diameter ex­ tends from the space between the spinous proce s of L4-L5 to the top of the pubic ymphysis. The posterior landmark-the inter pinous space-can be palpated at the superior angle of the Michaelis rhom­ boid, which is the diamond-shaped de­ pression overlying the lumbosacral re­ gion. This depression i s bounded laterally by the dimples overlying the posterior su­ perior iliac spines, superior to the L5 spinous process by the lines formed by the gl uteus muscles, and inferior to the groove at the end of the vertebral column.

Fig. 1 9-24 Lateral aspect of pelvis. A, Anteroposterior diameter of inlet. B, Posterior sagittal diameter of inlet. C, Anteroposterior diameter of midplane. D, Posterior sagittal diameter of midplane.

Pelvimetry

AP PROJECTION COLCHER-SUSSMAN METHOD The two projections (AP and lateral) em­ ployed in this method of pelvimetry re­ quire the use of the Colcher-Sussman pelvi meter. This device consists of a metal ruler perforated at centimeter intervals and mounted on a small stand in such a way that it is always parallel to the plane of the J R . The ruler can be rotated in .a complete circle and adj usted for height (Fig. 1 9-25 ) . Image receptor: 35 x 43 c m for each

exposure Position of patient •

Place the patient in the supine position, and center the midsagittal plane of the body to the midline of the grid.

Position of part •

•

•

•

Flex the patient's knees to elevate the forepelv is, and separate the thighs enough to permit correct placement of the pelvimeter. Center the horizontal ruler to the gluteal fold at the level of the ischial tuberosities. The tuberosities are easily pal pated through the median part of the buttocks. If preferred, local ize the tuberosities by placing the ruler 1 0 cm below the superior border of the pubic symphysis (Fig. 1 9-26). Center the I R I � inches (3.8 cm) supe­ rior to the pubic symphysis (Fig. 1 9-27). Respiration: After determining that the fetus is qu iet, instruct the patient to suspend respiration at the end of expiration.

Fig. 1 9-25 Colcher-Sussman ruler.

Fig. 1 9-26 Pelvimetry. AP projection. with ruler in place. E Inlet F = Mldpelvls T Outlet =

=

Central ray •

Perpendicular to the midpoint of the I R and 1 � inches (3.8 cm) superior to the pubic symphysis EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Entire pelvis • Metal ruler with centimeter markings visible • Density permitting visualization of all pelvic landmarks and intersecting di­ ameters • No rotation of the pelvis • Entire fetal head

Pubic symphysis Ischial tuberosity

Metal ruler

.1

--'_ _ -

_ _ _

---...;-

Fig. 1 9-27 Pelvimetry. AP projection.

267

Pelvimetry

LATE RAL PROJECTION

•

COLCHER-SUSSMAN M ETHOD R or L position

•

Imoge receptor: 35 x 43 cm •

Position of patient • A k the patient to turn to a lateral posi­

tion, and center the midcoronal plane of the patient's body to the midline of the table. Position of part

•

•

Partially extend the patient's thighs so that they do not obscure the pubic bones. Place sandbags under and between the patient' knee and ankle to i mmobi­ lize the legs. Place a folded sheet or other suitable support under the lower thorax, and ad­ just the support so that the long axis of the lumbar vertebrae is parallel with the tabletop.

•

•

Adjust the patient's body in a true lat­ eral position. Turn the ruler lengthwise, and adjust its height to coincide with the midsagittal plane of the patient's body. Place the pelvimeter so that the metal ruler l ies within the upper part of the gluteal fold and against the midsacrum (Fig. 1 9-28). Center the IR at the level of the most prominent point of the greater trochanter (Fig. 1 9-29). Respiration: Suspend at the end of ex­ piration.

Central ray

Perpendicular to the most prominent point of the greater trochanter EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Superimposed hips and femora • No superimposition of the pubic sym­ physis by the femurs • Entire pelvis, sacrum, and coccyx • Metal ruler with centi meter markings visible • Density permitting vi sual ization of all pelvic landmarks and intersecting diameters • Entire fetal head

Fig. 1 9-28 Pelvimetry, lateral projection with ruler in place.

Sacrum

Fetal head

Pubic symphysis Ischial tuberosities

Metal ruler

Fig. 1 9-29 Pelvimetry, lateral projection. 268

LOCALIZATION OF I NTRAUTERINE DEVICES Intrauterine devices ( f UDs) remain a con­ traceptive option. Occasionally an I U D becomes dislocated from the uterine cav­ ity. If this occurs, the exact location of the device must be determi ned, in some cases by radiography. Therefore it is necessary to become acquainted with the radio­ graphic appearance of I U D . The physician first performs a pelvic examination to determine the location of the I U D. If the ruD is not located, the physician passes a sterile probe into the uterine cavity and radiographs are taken. AP and lateral projections of the ab­ domen are suggested for f U D localiza­ tion. Occasionally, oblique projections are indicated. Most f U Ds are radiopaque be­ cause of their inherent metallic density or becau e of barium i mpregnated in the plastic during their manufacture. It should be emphasized that radiography alone is not a reliable way to diagnose extrauterine localization of an f UD. I n the early 1 9805 five types of I U Ds were available for u e. I n the late 1 980s three fUDs were removed from the U.S. market by their manufacturers. At this time only two fUDs are available for use in the United States: the Paragard and the Progestasert (Fig. 1 9-30).

--

INTRAUTERINE CONTRACEPTIVE DEVICES

-,-

r

"I

TATUM-T SEARLE

PROGI!STASERT

CU - 7

ALZA

SEARLE

SAF-T- COIL JUUUS SCHMID

1 I I

2 I

3 4 I I I CIII

Fig. 1 9-30 Intrauterine contraceptive devices.

269

Male Radiogra phy SEMINAL DUCTS Radiologic examinations of the seminal ducts ' ·3 are performed in the investigation of selected genitourinary abnormalities such as cysts, abscesses, tumors, inflam­ mation, and steril ity. The regional terms applied to these examinations are vesicu­ lography, epididymograp/7y, and, when combined, epididymovesiculography. The contrast medjum employed for these procedures is one of the water-soluble, iod­ inated compounds used for intravenous urography. A gaseous contrast medium can be injected into each scrotal ac to improve contrast in the examination of extrapelvic structures. ' Boreau J et al: Epididymography, Med Radiogr PhotogI' 29:63. 1 95 3 . 'Boreau J : L 'bl/de radiologique des voies .VI?minales I/oI'll/ales et pathologiques, Paris, 1 953, Masson & Cie. 'Vasselle B : Etude radiologique des voies sell/iI/ales de I 'holl/me, thesis. Paris, 1 953.

The seminal vesicle are sometimes opac ified directly by urethroscopic catheterization of the ejaculatory ducts. More frequently the entire duct system is inspected by introducing contrast solution into the canals by way of the ductus def­ erens. This requires small bi lateral inci­ sions in the upper part of the scrotum for the exposure and identification of these ducts. The needle that is used to inject the contrast medium is inserted into the duct in the direction of the portion of the tract under investigation-distally for study of the extrapelvic ducts and then proximally for study of the intrapelvic ducts.

A nongrid exposure technique is used for the delineation of extrapelvic struc­ tures (Figs. 1 9-3 1 to 1 9-33). The examin­ ing urologist places the IR and adj u ts the position of the testes for the desired pro­ jections of the ducts. A grid technique is used to demonstrate the intrapelvic ducts (Figs. 1 9-34 to 1 9-36). AP and oblique projections are made on 8 X 10 inch ( 1 8 X 24 cm) or 24 X 30 cm I Rs that are placed lengthwise and centered at the level of the superior border of the pubic symphysis.

Ductus deferens

Proximal convoluted ductus deferens

Epididymis Needle

Fig. 1 9-31 Epididymogram showing normal epididymis and origin of ductus deferens. The needle is at the epididymovasal kink, which can be palpated.

Fig. 1 9-32 Epididymogram demonstrating tuberculosis (cold ab­ scess) of epididymis (arrow).

270

Fig. 1 9-33 Epididymogram showing epididymal abscess (arrow) observed during acute orchitis (third relapse). Epididymovasal kink is atrophiC.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: AP projection • • •

I R centered at the level of the superior border of the pubic symphysis No rotation of the patient A short scale of contrast on radiograph

Distal ductus deferens

Oblique projection • • •

IR centered at the level of the superior border of the pubic symphysis No superi mposi tion of the seminal ducts by the i l ia No overlap of the region of the prostate or urethra by the uppermost thigh

Seminal vesicle

Proximal ductus deferens

PROSTATE Prostatography is a term applied to the i n­ vestigation of the prostate by radiographic, cystographic, or vesiculographic proce­ dures. It is seldom performed today be­ cause of advancements in the diagnostic value of ultrasonography. Radiographic examination of the prostate gland was de­ sClibed in the eighth and earlier editions of this atlas. Fig. 1 9-34 Normal vesiculogram.

1 9-35 Vesiculogram of tuberculous seminal vesicle associ­ ated with deferentitis, demonstrating small abscesses, ampul­ litis, and considerable vesiculitis on left (arrow). Fig.

Fig. 1 9-36 Vesiculogram demonstrating beginning (budding) metasta­ sis of crista urethralis (arrow) discovered 2 years after prostatectomy for cancer of prostate.

27 1

20

OURINE

SUM MARY OF PROJ ECTI ONS

PROJECTIONS,

POSITIONS,

& M ETHODS

306

Cranium

Lateral

308

Cranium

PA

308

Cranium

PA axial

312

Cranium

AP

312

Cranium

AP axial

314

Cranium

AP axial

TOWNE

320

Cranium

PA axial

HAAS

322

Cranial base

Submentovertical

SCH O LLER

324

Cranial base

Verticosubmental

SCH O LLER

326

Sella turcica

Lateral

328

Sella turcica, dorsum sellae, and clinoid

AP axial

330

Sella turcica, dorsum sellae, clinoid and

PA axial

334

Optic canal and foramen

Parietoorbital

RHESE

336

Optic canal and foramen

Orbitoparietal

RHESE

338 340

orbital fissures Inferior orbital fissures

R or L

PA axlal Lateral

346

PA axial

347

Parietoacanthlal Dacryocystography

CALDWELL

PA axial

345

349

R or L supine lateral

BERTEL R or L MODIFIED WATERS

Variable

Icons in the Essential column indicate projections frequently performed in the United States and Canada. Students should be competent in these projections.

i

ANATOMY

Skull The skull rests o n the superior aspect o f the vertebral column. It is made up of 22 sepa­ rate bones divided into two distinct groups: 8 cranial bones and 1 4 facial bones. The cranial bones are further divided into the calvaria and floor ( Box 20- 1 ). The cranial bones form a protective housing for the brain. The facial bones provide structure, shape, and support for the face. They also form a protective housing for the upper ends of the respiratory and digestive tracts and, with several of the cranial bones, form the orbital sockets for protection of the or­ gans of sight. The hyoid bone is commonly discussed with this group of bones. The bones of the skull are identified in Figs. 20- 1 to 20-3. The 22 pri mary bones of the skull should be located and recog­ nized in the different views before they are tudied in greater detail.

,·�fIt

BOX 20-1 Skull bones

Cranial bones (8) Calvaria frontal occipital right parietal left parietal Floor

ethmoid sphenoid right temporal left temporal

Parietal bone

Facial bones ( 1 4) nasal lacrimal maxillary zygomatic palatine inferior nasal conchae vomer mandible

2 2 2 2 2 2 1 1

Supraorbital foramen

Glabella Sphenoid bone

-�..-'r'-

Optic foramen

Superior orbital fissure _--\l!;;4':

Sphenoid bone

Temporal bone

Fig. 20- 1 Anterior aspect of cranium. 275

Bregma

Coronal suture

pterion

Glabella ---II'

Lambda

A

Occipital bone

External occipital protuberance (inion) External acoustic meatus Styloid process Crista galli

Cranial fossae

Orbital plate Optic canal and foramen

Anterior Tuberculum sellae

Lesser wing

Anterior clinoid process

Greater wing

Sella turcica Optic groove

B

Foramen ovale

Posterior clinoid process

Foramen spinosum

Foramen lacerum

Middle

Temporal bone

Dorsum sellae Diploe Jugular foramen Petrous portion Posterior Clivus (dashed line)

Hypoglossal canal

Occipital bone

Foramen magnum

Fig. 20-2 A, Lateral aspect of cranium. B, Superior aspect of cranial base.

276

The bones of the cranial vault are com­ posed of two plates of compact tissue sep­ arated by an inner layer of spongy tissue called diploe. The outer plate, or table, is thicker than the inner table over most of the vault, and the thickness of the layer of spongy tissue varies considerably. Except for the mandible, the bones of the cranium and face are joi ned by fibrous joints called sutures. The sutures are named coronal, sagittal, squamosal, and lambdoidal (see Figs. 20- 1 and 20-2). The

coronal suture is found between the frontal and parietal bones. The sagittal su­ ture is located on the top of the head be­ tween the two parietal bones and just be­ hind the coronal suture l ine (not visible in Figs. 20- 1 and 20-2). The j unction of the coronal and sagittal sutures is the bregma. Between the temporal bones and the pari­ etal bones are the squamosal sutures. Between the occipital bone and the pari­ etal bones is the lambdoidal suture. The lambda is the junction of the lambdoidal

and sagittal sutures. On the lateral aspect of the skull, the junction of the parietal bone, squamosal suture, and greater wing of the sphenoid is the pterion, which over­ l ies the middle meningeal artery. At the junction of the occipital bone, parietal bone, and mastoid portion of the temporal bone is the asterion. I n the newborn i nfant the bones of the cranium are thin and not fully developed. They contain a small amount of calcium, are indistinctly marked, and present six

Diploe

Parietal bone

Frontal bone

Frontal sinus

Nasal bone

Squamous portion of temporal bone

A Ethmoid bone

Internal acoustic meatus

---�IiI--:-

Vomer -----..�r-....".,�

Occipital bone

Palatine bone

Petrous portion of temporal bone

Cerebrum Bone (cross section) Fig. 20-3 A, Lateral aspect of interior of cranium.

B

Pons

B, Sagittal MRI image of the cranium showing con­

tents and position of the brain. Note the bony pro­ tective housing.

Cerebellum

Spinal cord

277

areas of i ncomplete ossification called Jontanels (Fig. 20-4). Two of the fontanels are situated in the midsagittal plane at the superior and posterior angles of the parietal bones. The anterior Jontanel is located at the junction of the two parietal bones and the one frontal bone at the bregma. Posteriorly and also in the midsagittal plane is the posterior Jontanel. located at the point labeled lambda in Fig. 20-2. Two fontanels are also on each side at the infe­ rior angles of the parietal bones. Each sphenoidal Jontanel is found at the site of the pterion; the mastoidJontanels are found at the asteria. The posterior and sphenoidal fontanels normally close in the first and third months after birth, respectively, and the anterior and mastoid fontanels close during the second year of life.

The cranium develops rapidly in size and density during the first 5 or 6 years, after which a gradual increase occurs un­ til adult size and density are achieved, usually by the age of 1 2 years. The thick­ ness and degree of mineralization in nor­ mal adult crania show comparatively l ittle difference in radiopacity from person to person, and the atrophy of old age is less marked than in other regions of the body. Internally, the cranial floor is divided into three regions: the anterior, middle, and posterior cranial fossae (see Fig. 20-2, B). The anterior cranial Jossa extends from the anterior frontal bone to the lesser wings of the sphenoid. I t is associated mainly with the frontal lobes of the cerebrum. The middle cranial Jossa accommodates the temporal lobes and associated neurovascu­ lar structures and extends from the lesser wings of the sphenoid bone to the apices of the petrous pOitions of the temporal bones. The deep depression posterior to the petrous ridges is the posterior cranial Jossa. which protects the cerebellum, pons, and medulla oblongata (see Fig. 20-3, B).

Anterior fontanel

Anterior fontanel

Sphenoidal fontanel

Mastoid fontanel Superior aspect

Lateral aspect

Fig. 20-4 Fontanels of a newborn.

278

The average or so-called normal cra­ nium is more or less oval in shape, bei ng wider in back than in front. The average cranium measures approximately 6 inches ( 1 5 cm) at its widest point from side to side, 7 i nches ( 1 7 .8 cm) at its longest point from front to back, and 9 inches (22 cm) at its deepest point from the vertex to the submental region. Crania vary in size and shape, with resultant variation in the position and relationship of i nternal parts. I nternal deviations from the norm are usual ly indicated by external deviations and thus can be estimated with a reason­ able degree of accuracy. The length and width of the normally shaped head vary by I inch (2.5 cm). Any deviation from this relationship indicates a comparable change in the position and relationship of the internal structures. If the deviation in­ volves more than a 5-degree change, it must be compensated for by a change i n either part rotation o r central ray angula­ tion. This "rule" applies to all images ex­ cept direct lateral projections. A �-inch ( 1 .3 cm) change in the I -inch (2.5-cm) width-to-length measurement indicates an approximate 5-degree change in the direc­ tion of the internal parts with reference to the midsagittal plane. It is i mportant for the radiographer to understand cranial anatomy from the standpoint of the size, shape, position, and relationship of the component parts of the cranium so that estimations and compen­ sations can be made for deviations from the norm.

Cranial Bones FRONTAL BONE Thefrontal bone has a vertical portion and horizontal portions. The vertical portion, called the frontal squama, forms the fore­ head and the anterior part of the vault. The horizontal portions form the orbital plates (roofs of the orbit ), part of the roof of the nasal cavity, and the greater part of the an­ terior cranial fossa (Figs. 20-5 to 20-7). On each side of the midsagittal plane of the superior portion of the squama is a rounded elevation called the frontal emi­ nence. Below the frontal eminences, just above the supraorbital margins, are two arched ridges that correspond in position to the eyebrows. These ridges are called the superciliary arches. In the center of the supraorbital margin is an opening for nerves and blood vessel called the supra­ orbitalforamen. The smooth elevation be­ tween the superciliary arches is termed the glabella. Thefrontal sinuses (see Chapter 22) are situated between the two tables of the squama on each side of the midsagittal plane. These irregularly shaped sinuses are separated by a bony wall , which may be i ncomplete and usually deviates from the midline. The quama articulates with the parietal bones at the coronal suture, the greater wing of the sphenoid bone at the fron­ tosphenoidal suture, and the nasal bones at the frontonasal suture. The midpoint of the frontonasal suture is termed the nasion. The frontal bone articulates with the right and left parietals, the sphenoid, and the ethmoid bones of the cranium. The orbital plates of the horizontal por­ tion of the frontal bone are separated by a notch called the ethmoidal notch. This notch receives the cribriform plate of the ethmoid bone. At the anterior edge of the ethmoidal notch is a small inferior projec­ tion of bone, the nasal spine, which is the most superior component of the bony nasal septum. The posterior margin of the orbital plates articulate with the lesser wings of the sphenoid bone.

Frontal squama

Supraorbital foramen

Supraorbital margin

Glabella

Nasal spine

Fig. 20-5 Anterior aspect of frontal bone.

Frontal

Supraorbital foramen

Fig. 20-6 Lateral aspect of frontal bone.

Glabella Nasal spine

,;:-'\I!tlr--- Superciliary arch Orbital plate

Ethmoidal air cells

Ethmoidal notch

Fig. 20-7 Inferior aspect of frontal bone.

279

ETHMOID BON E The ethmoid bone is a small , cube-shaped bone that consists of a horizontal plate, a vertical plate, and two l ight, spongy lat­ eral masses called labyrinths (Figs. 20-8 to 20- 1 0). Situated between the orbits, the ethmoid bone forms part of the anterior cranial fossa, the nasal cavity and orbital walls, and the bony nasal septum. The horizontal portion of the ethmoid bone, called the cribriform plate, is re­ ceived into the ethmoidal notch of the frontal bone. The cribriform plate is per­ forated by many foramina for the trans­ mission of olfactory nerves. The plate also has a thick, conical process, the crista galli, that projects superiorly from its an­ terior midline and serves as the anterior attachment for the fal x cerebri .

The vertical portion of the ethmoid bone is called the perpendicular plate. This plate is a thin, flat bone that projects inferiorly from the inferior surface of the cribriform plate and, with the nasal spine, forms the superior portion of the bony septum of the nose. The labyrinths contain the ethmoidal si­ nuses, or air cells. The cells of each side are arbitraril y divided into three groups: the anterior; middle, and posterior ethmoidal air cells. The wall s of the labyrinths form a part of the medial waIls of the orbits and a part of the lateral walls of the nasal cavity. Projecting inferiorly from each medial wall of the labyrinths are two thin, scroll-shaped processes called the superior and middle nasal conchae. The ethmoid bone articulates with the frontal and sphenoid bones of the cranium.

Crista galli

AI:"�f\-- Ethmoidal sinus

Superior nasal concha

Medial orbital wall

Middle nasal concha Perpendicular plate

Air cells in labyrinth

-----

" Fig. 20-8 Anterior aspect ot ethmoid bone.

Crista galll

;

�

With frontal

Crista galli

Articulates

with nasal

Cribriform plate

Posterior air cells

Articulates with cartilage of nasal septum

Fig. 20-9 Lateral aspect of ethmoid bone with labyrinth removed. 280

Fig. 20- 1 0 Superior aspect of ethmoid bone.

PARI ETAL BONES The two parietal bones are somewhat square and have a convex external surface and a concave internal surface (Figs. 20- 1 1 and 20- 1 2). The parietal bones form a large portion of the sides of the cranium. By their articulation with each other at the sagittal suture in the mid agittal plane, they also form the posterior portion of the cranial roof. Each parietal bone presents a promi­ nent bulge, called the parietal eminence, near the central portion of its external sur­ face. I n radiography the width of the head should be measured at this point because it is the widest point of the head. Each parietal bone articulates with the frontal, temporal, occipital, sphenoid, and opposite parietal bone of the cranium.

Articulates with opposite parietal bone

Articulates with frontal bone

Articulates with occipital bone

Articulates with temporal bone Fig. 20- 1 1 External surface of parietal bone.

Occipital angle

Frontal angle

Grooves for middle meningeal vessels

Mastoid angle --

Sphenoid angle

Fig. 20- 1 2 Internal surface of parietal bone.

281

SPH ENOID BONE The sphenoid bone is an irregularly wedge­ shaped bone that somewhat resembles a bat with its wings extended. It is situated in the base of the cranium anterior to the tempo­ ral bones and basilar part of the occipital bone (Figs. 20- 1 3 to 20- 1 5). The sphenoid bone consists of a body; two lesser wings and two greater wings, which project later­ ally from the sides of the body; and two pterygoid processes, which project inferi­ orly from each side of the inferior surface of the body.

Optic groove Greater wing

Optic conal

A Foramen rotundum

-l/I--- Foramen ovale

Tuberculum seliae

Foramen spinosum Selia turcica

Posterior clinoid process

Dorsum seliae

Carotid sulcus

Sphenoid sinus Greater wing of sphenoid Foramen ovale Foramen spinosum

B

Condyle process

Occipital bone

Fig. 20- 1 3 A, Superior aspect of sphenoid bone. B, Axial CT image of the sphenoid bone. (8, from Keliey L Petersen CM: Sectional anatomy, St Louis, 1 997, Mosby.)

282

The body of the sphenoid bone contains the two sphenoidal sinuses, which are in­ completely eparated by a median sep­ tum. The anterior surface of the body forms the posterior bony wall of the nasal cavity. The superior surface present a deep depression called the sella turcica and contains a gland called the pituitary gland. The sella turcica l ies in the mid­ sagittal plane of the cranium at a point % inch ( 1 .9 cm) anterior to and % inch ( 2 cm) superior to the level of the external acoustic meatus (EAM). The sella turcica is bounded anteriorly by the tuberculum sellae and posteriorly by the dorsum sel­ lae, which bear the posterior clinoid processes. The lanted area of bone poste­ rior and inferior to the dorsum sellae is continuous with the basilar portion of the occipital bone and is called the clivus. The clivus supports the pons. On either side of the sella turcica is a groove, the carotid sulcus, in which the i nternal carotid artery and cavernous sinus lie. The optic groove extends across the an­ terior portion of the tuberculum ellae. The groove ends on each side at the optic canal. The optic canal is the opening into the apex of the orbit for the transmi ion of the op­ tic nerve and ophthalmic artery. The actual opening i called the optic foramen.

The lesser wings are triangular in shape and nearly horizontal in position. They arise, one on each side, from the anterosu­ perior portion of the body of the sphenoid bone and project lateral ly, ending in sharp points. The lesser wing form the postero­ medial portion of the roofs of the orbits, the posterior portion of the anterior cra­ nial fossa, the upper margin of the supe­ rior orbital fissures, and the optic canals. The medial ends of their posterior borders form the anterior clinoid processes. Each process arises from two roots. The ante­ rior (superior) root is thin and fiat, and the posterior ( i nferior) root, referred to as the sphenoid strut, is thick and rounded. The circular opening between the two roots is the optic canal.

The greater wings arise from the sides of the body of the sphenoid bone and curve laterally, posteriorly, anteriorly, and superiorly. The greater wi ngs form a part of the middle cranial fossa, the posterolat­ eral wal ls of the orbits, the lower margin of the superior orbital sulci, and the greater part of the posterior margin of the i nferior orbital sulci. The foramina rotun­ dum, ovate, and spinosum are paired and are situated in the greater wings. Because these foramina transmit nerves and blood vessels, they are subject to radiologic in­ vestigation for the detection of erosive le­ sions of neurogenic or vascular origin.

Superior orbital fissure Posterior clinoid process

Dorsum sellae Sella turcica (contains pituitary gland)

Greater wing

-�- Lateral pterygoid lamina pterygoid hamulus Fig. 20- 1 4 Lateral aspect of sphenoid bone.

Optic canal and foramen

Anterior clinoid

Anterior clinoid processes Posterior clinoid processes Dorsum sellae

A Clivus --...,.f.-..:;,,,,

pterygoid process

Dorsum sellae

B

Lateral pterygoid ---....::! lamina

pterygoid hamulus

Fig. 20- 1 5 A, Oblique aspect of upper and lateroposterior aspects of sphenoid bone (right lateral pterygoid lamina removed). B, Sella turcica of sphenoid bone, lateral view.

283

The pterygoid processes arise from the lateral portions of the inferior surface of the body of the sphenoid bone and the me­ dial portions of the i nferior surfaces of the greater wings. These processes project in­ feriorly and curve laterally. Each ptery­ goid process consists of two plates of bone, the medial and lateral pterygoid laminae. which are fused at their su­ peroanterior parts. The inferior extremity of the medial lamina possesses an elon­ gated, hook-shaped process, the pterygoid hamu.lus, which makes it longer and nar­ rower than the lateral lamina. The ptery­ goid processes articulate with the palatine bone anteriorly and with the wings of the vomer where they enter into the formation of the nasal cavity. The sphenoid bone articulates with each of the other seven bones of the cranium.

Squama

OCCIPITAL BONE The occipital bone is situated at the pos­ teroinferior part of the cranium. It forms the posterior half of the base of the cra­ nium and the greater part of the posterior cranial fossa (Figs. 20- 1 6 to 20- 1 8) . The occipital bone has four parts: the squama, which is saucer-shaped, being convex ex­ ternally; two occipital condyles, which ex­ tend anteriorly, one on each side of the foramen magnum; and the basilar por­ tion. The occipital bone also has a large aperture, the foramen magnum. through which the inferior portion of the medulla oblongata passes as it exits the cranial cavity and joins the spinal cord.

The squama curves posteriorly and su­ periorly from the foramen magnum and is also curved from side to side. It articu­ lates with the parietal bones at the l amb­ doidal suture and with the mastoid por­ tions of the temporal bones at the occipitomastoid suture . On the external surface of the squama, midway between its summit and the foramen magnum, is a promi nent process termed the external occipital protuberance. or inion. that cor­ responds in position with the internal oc­ cipital protuberance.

External occipital protuberance (Inion)

B Occipital condyle

--±��iIiiI'--- Foramen

magnum

Atlanto-occipital joint Lateral mass C-l Odontoid process C-2

Fig. 20- 1 6 A, External surface of occipital bone. B, Coronal MRI image shows the atlanto­ OCCipital joint. (B, Courtesy Siemens Medical Systems. Iselin. NJ.)

284

The occipital condyLes project anteri­ orly, one from each side of the squama for articulation with the atlas of the cervical spine. Part of each lateral portion curves medially to fuse with the basilar portion and thus complete the foramen magnum, and part of it projects laterally to form the jugular process. On the inferior surface of the curved parts, extending from the level of the middle of the foramen magnum an­ teriorly to the level of its anterior margin, reciprocally shaped condyles articulate with the superior facets of the atlas. These articulations, known as the occipitoat­ LantaL joints, are the only bony articula­ tions between the skull and the neck. The hypogLossaL canaLs are found at the ante­ rior ends of the condyles and transmit the hypoglossal nerves. At the posterior end of the condyles are the condylar canaLs, through willch the emissary veins pass. The anterior portion of the occipital bone contains a deep notch that forms a part of the juguLar foramen (see Fig. 20-2, B). The jugular foramen is an important l arge opening i n the skull for two reasons: it al­ lows blood to drain from the brain via the internal j ugular vein, and it lets three cra­ ilial nerves pass through it.

The basilar portion of the occipital bone curves anteriorly and superiorly to its j unction with the body of the sphenoid. In the adult the basilar part of the occipi­ tal bone fuses with the body of the sphe­ noid bone, resulting in the formation of a continuous bone. The sloping surface of tills junction between the dorsum sellae of the sphenoid bone and the basilar portion of the occipital bone is called the clivus. The occipital bone articulates with the two parietals, the two temporals and the sphenoid of the cranium, and the first cer­ vical vertebra.

Fossa for cerebrum

��;--'jr.-- Internal occipital protuberance --��- Fossa for cerebellum Hypoglossal canal Basilar oOltior1 ---�

ugular process Condyle for articulation with atlas

Fig. 20- 1 7 Internal surface of occipital bone.

Squama

External occipital protuberance (inion)

Foramen magnum

Condyles for articUlation with the atlas

Fig. 20- 1 8 Lateroinferior aspect of occipital bone.

285

TEMPORAL BONES The temporal bones are irregular in shape and are ituated on each side of the base of the cranium between the greater wings of the sphenoid bone and the occipital bone ( Figs. 20- 1 9 to 20-22). The temporal bones form a large part of the middle fossa of the cranium and a small part of the pos­ terior fossa. Each temporal bone consists of a squamous portion, a tympanic portion, a styloid process, a zygomatic process, and a petromastoid portion (the mastoid and petrous portions) that contains the organs of hearing and balance. The squamous portion is the thin, upper portion of the temporal bone. It forms a part of the side wall of the cranium and has a prominent arched process, the zygo­ matic process, which projects anteriorly to articulate with the zygomatic bone of the face and thus complete the zygomatic

arch. On the inferior border of the zygo­ matic process is a rounded eminence, the articular tubercle, which forms the ante­ rior boundary of the mandibular fossa. The mandibular fossa receives the condyle of the mandible to form the tem­ poromandibular joint (TMJ). The tympanic portion is situated below the squama and in front of the mastoid and petrous portions of the temporal bone. This portion forms the anterior wall , infe­ rior wal l, and part of the posterior walls of the EAM. The EAM is approximately 'li inch ( 1 . 3 cm) in length and projects medi­ aJJy, anteriorly, and slightly superiorly. The styloid process, a slender, pointed bone of variable length, projects inferi­ orly, anteriorly, and slightly medially from the i nferior portion of the tympanic part of the temporal bone.

ZygomatiC process Mastoid portion

Articular tubercle

Mastoid process

Tympanic portion

Fig. 20- 1 9 Lateral aspect of temporal bone.

Squamous portion

Petrous portion

Internal acoustic meatus

Styloid process ---# Fig. 20-20 Internal surface of temporal bone.

286

Petromastoid Portion

The petrous and mastoid portions together are called the petromastoid portion. The mastoid portion, which forms the i nferior, posterior part of the temporal bone is pro­ longed into the conical mastoid process (see Figs. 20-2 1 and 20-22). The mastoid portion articulates with the parietal bone at its superior border through the parietomastoid suture and with the oc­ cipital bone at its posterior border through the occipitomastoid suture, which is con­ tiguous with the lambdoidal suture. The mastoid process varies considerably i n size, depending o n its pneumatization, and is larger in males than in females. The first of the mastoid air cells to de­ velop is situated at the upper anterior part of the process and is termed the mastoid antrum. This air cell is quite l arge and communicates with the tympanic cavity. Shortly before or after birth, smaller air cells begin to develop around the mastoid antrum and continue to increase in number and size until around puberty. However, the air cells vary considerably in both size and number. Occasionally they are absent altogether, in which case the mastoid process is solid bone and is usually small. The petrous portion, often called the petrous pyramid, is conical or pyramidal and is the thickest, densest bone in the cra­ nium. This part of the temporal bone con­ tains the organs of hearing and balance. From its base at the squamous and mastoid portions, the petrous portion projects medi­ ally and anteriorly between the greater wing of the sphenoid bone and the occipital bone to the body of the sphenoid bone, with which its apex ruticulates. The internal carotid artery in the carotid canal enters the infelior aspect of the petrous portion, passes superior to the cochlea, then passes medi­ ally to exit the petrous apex. Near the petrous apex is a ragged foramen called the foramen lacerum. The carotid canal opens into this foramen, which contains the inter­ nal carotid artery (see Fig. 20-2, B). At the center of the posterior aspect of the petrous portion is the internal acoustic meatus (lAM), which transmits the vestibulo­ cochlear and facial nerves. The upper bor­ der of the petrous portion is commonly re­ ferred to as the petrous ridge. The top of the ridge lies approximately at the level of an external radiography landmark called the top of ear attachment (TEA). The temporal bone articulates with the parietal, occipital, and sphenoid bones of the cranium.

I I r

I

I

I

Squamous portion

'. ,

\ \ \

,

Petrous portion

"'

� "'- - - - - - - - � '"

'

Mastoid air cells

B - Petrous apex Carotid canal

>

A

Fig. 20- 2 1 A, Anterior aspect of temporal bone in relation to surrounding structures. B, Coronal section through mastoid and petrous portions of the temporal bone

StylOid process

Inner ear

External auditory meatus

Petrons portion, temporal bone Mastoidain cells

Fig. 20-22 Axial CT image of the petrous portion at the level of the external auditory meatus.

(From Kelley L Petersen CM: Sectional anatomy. St Louis, 1 997, Mosby.)

287

I

/ /

/

/

�

�

,,

�

,,

,

,

I I I

A

Top of ear attachment External acoustic meatus

, , , , ,

\

/

,

�I

; ....-"''{\ . \'''' --.... ,

"® ' --\

·

�

.1

�

/i\ ,' �""\ :I" : ...: \.c!!D ) _ _ -

,

,

\

\

, ,

I I I I I I I

,

, I

Tragus Auditory tube

�

Helix

Cochlear nerve

B Auricle

External acoustic meatus

Tympanic cavity

Tympanic membrane Perilymph Semicircular canals

c

Fig. 20-23 A, Frontal view of the face, showing internal structures of ear (shaded area). B, External. middle, and internal ear. C, Internal ear.

288

Ear The ear is the organ of hearing and bal­ ance (Fig. 20-23). The essential parts of the ear are housed in the petrous portion of the temporal bone. The organs of hear­ ing and equi librium consist of three main divisions: the external ear, middle ear, and internal ear.

EXTERNAL EAR The external ear consists of two parts: ( 1 ) the oval-shaped, fibrocartilaginous, sound­ collecting organ situated on the side of the head known as the auricle and (2) a sound­ conducting canal, the EAM. The auricle has a deep central depression, the concha, the lower part of which leads into the EAM. At its anterior margin the auricle has a prominent cartilaginous l ip, the tra­ gus, which projects posteriorly over the entrance of the meatus. The outer rim of the ear is the helix. The EAM is about I i nch (2.5 cm) in length. The outer third of the canal wall is cartilaginous, and the in­ ner two thirds are osseous. From the meatal orifice the canal forms a slight curve as it passes medially and anteriorly in line with the axis of the lAM. The EAM ends at the tympanic membrane of the middle ear.

MI DDLE EAR The middle ear is situated between the ex­ ternal and internal ear. The middle ear proper consists of ( 1 ) the tympanic mem­ brane (or eardrum), (2) an irregularly shaped, air-containing compartment called the tympanic cavity, and (3) three small bones called the auditory ossicles. The middle ear communicates with the mas­ toid antrum and auditory eustachian tube.

The tympanic membrane is a thin, con­ cavoconvex, membranous disk with an el­ liptic shape. The disk, the convex surface of which is directed medially, is situated obliquely over the medial end of the EAM and serves as a partition between the ex­ ternal and middle ear. The function of the tympanic membrane is the transmission of sound vibrations. The tympanic cavity is a narrow, irreg­ ularly shaped chamber that l ies just poste­ rior and medial to the mandibular fossa. The cavity is separated from the external ear by the tympanic membrane and from the internal ear by the bony labyrinth. The tympanic cavity communicates with the nasopharynx through the auditory (eu­ stachian) tube, a passage by which air pressure in the middle ear is equalized with the pressure in the outside air pas­ sages. The auditory tube is about I Y.t inches (3 cm) long. From its entrance into the tympanic cavity, the auditory tube passes medially and inferiorly to its ori­ fice on the lateral wall of the nasopharynx. The mastoid antrum is the large air cav­ ity situated in the temporal bone above the mastoid air cells and immediately behind the posterior wall of the middle ear. The auditory ossicles, named for their shape, are the malleus (hammer), incus (anvil), and stapes (stirrup). These three delicate bones are articulated to permit vi­ bratory motion. They bridge the middle ear cavity for the transmission of sound vibrations from the tympanic membrane to the internal ear. The handle of the malleus (the outermost ossicle) is attached to the tympanic membrane, and its head articulates with the icus (the central ossi­ cle). The head of the stapes (the innermost ossicle) articulates with the incus, and its base is fitted into the oval window of the inner ear.

I NTERNAL EAR The internal ear contains the essential sen­ sory apparatus of hearing and equilibrium and lies on the densest portion of the petrous portion i mmediately below the ar­ cuate eminence. Composed of an irregu­ larly shaped bony chamber called the bony labyrinth, the internal ear is housed within the bony chamber and is an intercommuni­ cating system of ducts and sacs known a the membranous labyrinth. The bony labyrinth consists of three distinctly shaped parts: ( I ) a spiral-coi led, tubular part called the cochlea, which communi­ cates with the middle ear through the membranous covering of the round win­ dow; (2) a small, ovoid central compart­ ment behind the cochlea, known as the vestibule, which communicates with the middle ear by way of the oval window; and (3) three uneqUally sized semicircular canals that form right angles to one an­ other and are called, according to their po­ sitions, the anterior, posterior, and lateral semicircular canals. From its cranial ori­ fice the l A M passes inferiorly and laterally for a distance of about Y2 inch ( 1 .3 cm). It is through this canal that the cochlear and vestibular nerves pass from their fibers in the respective parts of the membranous labyrinth to the brain. The cochlea is used for hearing, and the vestibule and semicir­ cular canals are involved with equilibrium.

289

Facial Bones

MAXILLARY BONES

NASAL BONES The two smal l, thin nasal bones vary in size and shape in different individuals ( Fig . 20-24 and 20-25 ). They form the superior bony wall (called the bridge of the nose) of the nasal cavity. The nasal bones articulate in the midsagittal plane, where at their postero uperior surface they also articulate with the perpendicular plate of the ethmoid bone. They articulate with the frontal bone above and with the maxillae at the sides. LACRIMAL BONES The two lacrimal bones, which are the smallest bones in the skull, are very thin and are situated at the anterior part of the medial wal l of the orbits between the labyrinth of the ethmoid bone and the max­ il la ( see Figs. 20-24 and 20-25 ). Together with the maxil lae, the lacrimal bones form the lacrimal fossae, which accommodate the lacrimal sacs. Each lacrimal bone con­ tains a lacrimal foramen through which a tear duct passes. Each lacrimal bone artic­ ulates with the frontal and ethmoid cranial bones and the maxilla and inferior nasal concha facial bones. The lacrimal bones can be seen on PA and lateral projection of the skull .

The two maxillary bones are the largest of the immovable bones of the face (see Figs. 20-24 and 20-25 ). Each articulates with all other facial bones except the mandible. Each also articulates with the frontal and ethmoid bones of the cranium. The maxil­ lary bones form part of the lateral walls and most of the floor of the nasal cavity, part of the floor of the orbital cavities, and three fourths of the roof of the mouth. Their zygomatic processes articulate with the zygomatic bones and assist in the for­ mation of the prominence of the cheeks. The body of each maxilla contains a large, pyramidal cavity called the maxillary si­ nus, which empties into the na al cavity. An infraorbital foramen is located under each orbit and serves as a passage through which the infraorbital nerve and artery reach the nose.

At their inferior borders the maxillae possess a thick, spongy ridge called the alveolar process, which supports the roots of the teeth. In the anterior midsagittal plane at their j unction with each other, the maxillary bones form a pointed, forward­ projecting process cal led the anterior nasal spine. The midpoint of this promi­ nence is called the acanthion.

OptiC foramen Superior orbital fissure _---Ifuc---r--:

Lacrimal bone

Zygoma ------\rc----

Ethmoid bone

Inferior orbital fissure

Infraorbital foramen Vomer

Inferior nasal concha Anterior nasal spine (acanthion)

Mental protuberance Fig. 20-24 Anterior aspect of skull. demonstrating facial bones.

290

ZYGOMATIC BONES The zygomatic bones form the promi­ nence of the cheeks and a part of the side wall and floor of the orbital cavities (see Figs. 20-24 and 20-25). A posteriorly ex­ tending temporal process unites with the zygomatic process of the temporal bone to form the zygomatic arch. The zygomatic bones articulate with the frontal bone su­ periorly, with the zygomatic process of the temporal bone at the side, with the maxilla anteriorly, and with the sphenoid bone posteriorly. PALATI NE BONES The two palatine bones are L-shaped bones composed of vertical and horizontal plates. The horizontal plates articulate with the maxillae to complete the posterior fourth of the bony palate, or roof of the mouth (see Fig. 20-3). The vertical portions of the pala­ tine bones extend upward between the max­ il lae and the pterygoid processes of the sphenoid bone in the posterior nasal cavity. The superior tips of the vertical portions of the palatine bones assist in forming the pos­ teromedial bony orbit.

INFERIOR NASAL CONCHAE The inferior nasal conchae extend diago­ nally and inferiorly from the lateral walls of the nasal cavity at approxi mately its lower third (see Fig. 20-24). They are long, narrow, and extremely thin; they curl laterally, which gives them a scroll­ like appearance. The upper two nasal conchae are processes of the ethmoid bone. The three nasal conchae project into and divide the lateral portion of the respective sides of the nasal cavity i nto superior, middle, and inferior meatuses. They are covered with a mucous membrane to warm, moisten, and cleanse inhaled air.

VOMER The vomer is a thin plate of bone situated in the midsagittal plane of the floor of the nasal cavity, where it forms the inferior part of the nasal septum (see Fig. 20-24). The anterior border of the vomer slants superiorly and posteriorly from the ante­ rior nasal spine to the body of the sphe­ noid bone, with which its superior border articulates. The superior part of its ante­ rior border articulates with the perpendic­ ular plate of the ethmoid bone; its poste­ rior border is free.

lacrimal bone

Ethmoid bone

Anterior nasal spine (acanthion)

Temporal process

Alveolar process

Mental foramen

External acoustic meatus Mandibular condyle Angle (gonion) Mandibular notch Coronoid process

Fig. 20-25 Lateral aspect of skull, demonstrating facial bones. 291

MANDIBLE The mandible, the largest and densest bone of the face, consists of a curved hor­ izontal portion, called the body, and two vertical portions, called the rami, whjch unite with the body at the angle of the manilible, or gonion (Fig. 20-26). At birth the mandible consists of bilateral pieces held together by a fibrous symphysis that ossifies during the first year of life. At the site of ossification is a slight ridge that ends below in a triangular prorrunence, the mental protuberance. The symphysis is the most anterior and central part of the mandible. This is where the left and right halves of the mandible have fused.

The superior border of the body of the mandible consists of spongy bone, called the alveolar portion, whkh supports the roots of the teeth. Below the second pre­ molar tooth, approxi mately halfway be­ tween the superior and inferior borders of the bone, is a small opening on each side for the transrrussion of nerves and blood vessels. These two openings are called the

mental foramina.

�

The rami project superiorly at an obtuse angle to the body of the mandible, and their broad surface forms an angle of ap­ proximately 1 1 0 to 1 20 degrees. Each ra­ mus presents two processes at its upper extrerruty, one coronoid and one condylar, wruch are separated by a concave area called the mandibular notch. The anterior process, the coronoid process, is thjn and tapered and projects to a higher level than the posterior process. The condylar process consists of a constricted area, the neck, above which is a broad, truck, al­ most transversely placed condyle that ar­ ticulates with the mandibular fossa of the temporal bone (see Fig. 20- 1 3, B). Thjs articulation, the TMJ, slants posteriorly approxi mately 1 5 degrees and inferiorly and medially approximately 1 5 degrees. Radiograpruc projections, produced from the opposite side, must reverse these di­ rections. In other words, the central ray angulation must be superior and anterior to coincide with the long axis of the joint. The TMJ is situated immediately in front of the EAM .

OndYle

Condylar process

Coronoid process

Neck

Ramus

A Angle

Body Mental foramen

Mental protuberance

Condylar

Alveolar portion 8

Lesser cornu Mental --�'" protuberance Mental foramen

Body

Fig. 20-26 A, Anterior aspect of mandible. B, Lateral aspect of mandible.

292

Fig. 20-27 Anterior aspect of hyoid.

HYOID BONE The hyoid bone i a small , U-shaped struc­ ture situated at the base of the tongue, where it is held in position in part by the stylohyoid ligaments extending from the styloid processes of the temporal bones (Fig. 20-27). Although the hyoid bone is an accessory bone of the axial skeleton, it is described in this chapter because of its connection with the temporal bones. The hyoid is the only bone in the body that does not articulate with any other bone. The hyoid bone is divided into a body, two greater cornua, and two lesser cornua. The bone serves as an attachment for cer­ tain muscles of the larynx and tongue and is easily palpated just above the larynx.

ORBITS Each orbit is made up of seven different bones (Fig. 20-28). Three of these are cra­ nial bones: frontal, sphenoid, and ethmoid. The other four bones are the facial bones: maxilla, zygoma, lacrimal, and palatine. The circumference of the orbit, or outer rim area, is made up of three of the seven bones-the frontal, zygoma, and maxilla. The remaining four bones make up most of the posterior aspect of the orbit.

Articulations of the Skull The sutures o f the skull are connected by toothl i ke projections of bone interlocked with a thin layer of fibrous tissue. These articulations al low for no movement and are classified as fibrous joints of the suture type. The articulations of the facial bones, including the joints between the roots of the teeth and the jawbones, are fibrous gomphoses. The exception is the point at which the rounded condyle of the mandible articulates with the mandibular fossa of the temporal bone to form the TMJ. The TMJ articulation is a synovial joint of both the hinge and gliding type. The atlanto-occipital joint is a synovial ellipsoidal joint that joins the base of the skull (occipital bone) with the atlas of the cervical spine. The seven joints of the skull are summarized i n Table 20- 1 .

TABLE 20- 1 Joints of the skull

Structural classification Joint

Tissue

Coronal suture Sagittal suture Lambdoidal suture Squamosal suture Temporomandibular Alveolar sockets Atlanto-occipital

Fibrous Fibrous Fibrous Fibrous Synovial Fibrous Synovial

Frontal

Type

Movement

Suture Suture Suture Suture Hinge and gliding Gomphosis Ellipsoidal

Immovable Immovable Immovable Immovable Freely movable Immovable Freely moveable

� Sphenoid (greater wing)

Ethmoid

Palatine Medial

lateral

Orbital surface of maxilla

\ Zygoma

(

Fig. 20-28 The orbit. The seven bones of the orbit are shown. 293

SUMMARY OF ANATOMY* Skull

Fossae

Sphenoid bone

Occipital bone

cranial bones (8) facial bones ( 1 4)

anterior cranial fossa middle cranial fossa posterior cranial fossa

body sphenoidal sinuses sella turcica tuberculum sellae dorsum sellae posterior clinoid processes clivus carotid sulcus optic groove optic canals optic foramen lesser wings superior orbital fissures anterior clinoid processes sphenoid strut greater wings foramen rotundum foramen ovale foramen spinosum pterygoid processes medial pterygoid lamina pterygoid hamulus lateral pterygoid lamina

foramen magnum squama external occipital protuberance (inion) internal occipital protuberance occipital condyles hypoglossal canals condylar canals jugular foramen basilar portion clivus

Cranial bones

calvaria frontal right parietal left parietal occipital floor right temporal left temporal sphenoid ethmoid diploe Sutures

coronal suture sagittal suture squamosal sutures lambdoidal suture bregma lambda pterion asterion Fontanels

anterior fontanel posterior fontanel sphenoidal fontanels (2) mastoid fontanels (2)

Frontal bone

frontal squama frontal eminence supraorbital margins superciliary arches supraorbital foramen glabella frontal sinuses nasion orbital plates ethmoidal notch nasal spine Ethmoid bone

cribriform plate crista galli perpendicular plate labyrinths anterior air cells middle air cells posterior air cells ethmoidal sinuses superior nasal conchae middle nasal conchae Parietal bones

parietal eminence

Temporal bones

squamous portions zygomatic process articular tubercle mandibular fossa tympanic portions external acoustic meatus (EAM) styloid process petromastoid portions mastoid portions mastoid process mastoid antrum mastoid air cells petrous portions (petrous pyramids) carotid canals petrous apex foramen lacerum internal acoustic meatus (lAM) petrous ridge top of ear attachment (TEA)

'See Addendum at the end of the volume for a summary of the changes in the anatomic terms used in this edition.

294

SUMMARY OF ANATOMY* Ear

Facial bones ( 1 4)

external ear auricle concha tragus helix external acoustic meatus (EAM) middle ear tympanic membrane tympanic cavity auditory (eustachian) tube auditory ossicles malleus incus stapes internal ear arcuate eminence bony labyrinth cochlea round window vestibule oval window semicircular canals anterior posterior lateral membranous labyrinth

nasal (2) lacrimal (2) maxillary (2) zygomatic (2) palatine (2) inferior nasal conchae (2) vomer ( 1 ) mandible ( 1 ) hyoid bone diploe

Inferior nasal conchae (2) Vomer ( 1 )

nasal septum Mandible ( 1 )

maxillary sinus infraorbital foramen alveolar process anterior nasal spine acanthion

body alveolar portion mental foramina angle (gonion) rami coronoid process condylar process condyle neck temporomandibular joint (TMJ) mandibular notch mental protuberance (mentum) symphysis

Zygomatic bones (2)

Hyoid bone

temporal process zygomatic arch

body greater cornua lesser cornua

lacrimal bones (2)

lacrimal foramen Maxillary bones (2)

Palatine bones (2)

vertical plates horizontal plates

Articulations

coronal suture sagittal suture lambdoidal sutures squamosal sutures temporomandibular alveolar sockets atlanto-occipital Morphology

mesocephalic brachycephalic dolicocephalic Orbit

base apex optic foramen superior orbital fissures inferior orbital fissures Eye

eyeball conjunctiva sclera cornea retina rods cones

'See Addendum at the end of the volume for a summary of the changes in the anatomic terms used in this edition.

295

SUM MARY OF PATHOLOGY

296

Condition

Definition

Fracture

Disruption in the continuity of bone

Basal

Fracture located at the base of the skull

Blowout

Fracture of the floor of the orbit

Contre-coup

Fracture to one side of a structure caused by trauma to the other side

Depressed

Fracture causing a portion of the skull to be depressed into the cranial cavity

Leforte

Bilateral horizontal fractures of the maxillae

Linear

Irregular or jagged fracture of the skull

Tripod

Fracture of the zygomatic arch and orbital floor or rim and dislocation of the frontozygo­ matic suture

Mastoiditis

Inflammation of the mastoid antrum and air cells

Metastases

Transfer of a cancerous lesion from one area to another

Osteomyelitis

Inflammation of bone due to a pyogenic infection

Osteopetrosis

Increased density of atypically soft bone

Osteoporosis

Loss of bone density

Paget's Disease

Thick, soft bone marked by bowing and fractures

Polyp

Growth or mass protruding from a mucous membrane

Sinusitis

Inflammation of one or more of the paranasal sinuses

TMJ Syndrome

Dysfunction of the temporomandibular joint

Tumor

New tissue growth where cell proliferation is uncontrolled

Acoustic Neuroma

Benign tumor arising from Schwann cells of the eighth cranial nerve

Multiple Myeloma

Malignant neoplasm of plasma cells involving the bone marrow and causing destruction of the bone

Osteoma

Tumor composed of bony tissue

Pituitary Adenoma

Tumor arising from the pituitary gland, usually in the anterior lobe

EXPOSURE TECH N I QUE CHART ESSE NTIAL PROJ ECTI ONS SKULL

Part

em

kVp'

Cranium* Lateral

15

80

PA

20

PA Axial (Caldwell)

AEC

SID

2005

0.0

48"

24

x

30 em

98

80

200s

0.0

48"

24

x

30 em

21 1

20

80

2005

0.0

48"

24

x

30 em

21 1

AP

20

80

2005

0.0

48"

24

x

30 em

21 1

AP Axial

20

80

2005

0.0

48"

24

x

30 em

21 1

AP Axial (Towne)

22

80

2005

0.0

48"

24

x

30 em

252

PA Axial (Haas)

21

80

200s

0.0

48"

24

x

30 em

220

23

80

2005

0.0

48"

24

x

30 em

329

23

80

2005

0.0

48"

24

x

30 em

329

Sella Tureiea* Lateral

15

80

2005

0.0

48"

8

x

1 0 in

1 19

Optie Canal & Foramen* Parietoorbital Obi. Orbitoparietal Obi.

21 21

80 80

48" 48"

8 8

x x

10 in 1 0 in

220 220

Cranial Ba5e* SMV VSM

tm

0.09 0.09

mA

200s 200s

mAs

18 18

IR

Dose! (mrad)

s.

Small focal spot. ·kVp values are for a 3-phase 1 2-pulse generator. 'Relative doses for comparison use. All doses are skin entrance for average adult at cm indicated. 'Bucky. 1 6: 1 Grid. Screen/Film Speed 300.

297

RAD I OGRAPHY

.

Skull Topography The basic localization points and planes of the skull (all of which can be either seen or palpated) used in radiographic poitioning are illustrated in Figs. 20-29 and 20-30.

Accurate positioni ng of the skull re­ quires a full understanding of these land­ marks, which shouLd be studied thor­ oughly before positioning of the skull is Learned. The planes, points, lines, and ab­ breviations most frequently used in skull positioning are as fol lows: • Midsagittal plane • I nterpupillary l ine • Acanthion • Outer canthus • Infraorbital margin • External acollstic meatlls (EAM) • Orbitomeatal line (OML) • lnfraorbitomeatal l ine ( IOML) • Acanthiomeatal line (AML) • Mentomeatal l ine (MML)

�':';;::�

In the adult an average 7-degree angle difference exists between the OML and IOML, and an average 8-degree angle dif­ ference exist between the OML and the glabellomeatal l ine. The degree difference between the cranial positioning lines must be recognized. Often the relationship of the patient, I R, and central ray is the same, but the angle that is described may vary, depending on the cranial l ine of reference.

Midsagittal plane Top of ear attachment

Auricle

Glabella

Outer canthus

Interpupillary line

Infraorbital ---41-.'<-----­ margin

Angle of mandible (gonion)

�---,-fTi- lnner canthus

Nasion Acanthion

I--�"--t--- Mental point Mental point

Fig. 20-29 Anterior landmarks.

298

Fig. 20-30 Lateral landmarks.

Skull Morphology Radiographic i mages of the skull are all based on the normal size and shape of the cranium. Rules have been established for the centering and adjustment of localiza­ tion points and planes and for the exact degree of central ray angulation for each projection. Although the heads of many patients fall within the li mit of normality and can be radiographed satisfactorily us­ ing the established positions, a consider­ able number of skulls vary enough i n shape that the standard procedure must be adjusted to obtain an undistorted i mage. In the typically shaped head (Fig. 203 1 ), the petrous pyramids project anteri­ orly and medially at an angle of 47 degrees from the mid agittal plane of the skul l . The superior borders o f these tructures are situated in the base of the cranium.

Fig. 20-31 Mesocephalic skull.

Depending on its shape, the atypical cranium requires more or less rotation of the head or an i ncrease or decrease in the angulation of the central ray compared with the typical, or mesocephalic, skull (see Fig. 20-3 1 ). I n the brachycephalic skull (Fig. 20-32), which is sholt from front to back, broad from side to side, and shallow from vertex to base, the internal structures are higher with reference to the IOML and their long axes are more frontal in position (i .e., the petrous pyramids form a wider angle with the midsagittal plane) . The petrous pyramids lie at an av­ erage angle of 54 degrees. In the dolicho­ cephalic skull (Fig. 20-33), which is long from front to back, narrow from side to side, and deep from vertex to base, the in­ ternal structures are lower with reference to the IOML and their long axes are less frontal in position ( i .e., the petrous pyra­ mids form a narrower angle with the mjdagittal plane). The petrous pyramids form an average angle of 40 degrees i n the dolichocephalic skull.

Fig. 20-32 Brachycephalic skull.

Asymmetry must aI 0 be con idered. For example, the orbits are not alway symmetric in size and shape, the lower jaw is often asymmetric, and the na al bone and cartil age are frequently deviated from the midsagittal plane. Many deviations are not as obvious as these, but if the radiog­ rapher adheres to the fundamental rules of positiorung, relatively l ittle difficulty will be encountered. Varying the position of the part or the degree of central ray angUlation to compensate for structural variations be­ comes a simple procedure if care and pre­ cision are used initially.

Fig. 20-33 Dolichocephalic skull.

299

I f possible, the radiography student should obtain a dry skull specimen and ra­ diograph it in the standard positions. This is the best technique for studying the anatomy of the different parts of the cra­ nium from both actual and radiographic standpoint . It is important to compare the actual structure ( its position in the head, its relationship to adjacent structures in each radiographic po ilion, and its rela­ tionship to the I R and the central ray an­ gulation) with the resultant i mage on the radiograph. In this way the radiographer can develop the abi lity to look at a head as if it were transparent-to visualize the lo­ cation and direction of the internal parts according to the shape of the cranium. B y studying the i mage cast b y the part being examined with reference to its relation­ ship to the images of the adjacent struc­ tures, the radiographer learns to detect quickly and accurately any error in the im­ age and any deviation from the normal cranium that requires compensation.

It is also advisable to keep a complete set of radiographs of a normally shaped skul l . These radiographs can be used for comparison with atypical skulls in deter­ mining the deviation and the correct ad­ j ustment to make in the degree and direc­ tion of part rotation or central ray angulation. Radiographic examples of correct and incorrect rotation skull rota­ tion are shown in Figs. 20-34 and 20-35. The radiographic positions depicted in Chapters 20 to 23 show the patient either seated at the vertical grid device or lying on a radiographic table. Whether the radiogra­ pher elects to perform the examination with the patient in the recumbent or upright position depends on four variables: ( I ) the equipment available, (2) the age and condi­ tion of the patient, (3) the preference of the radiographer and/or radiologist, and (4) whether upright images would increase di­ agnostic value, such as showing air-fluid levels in paranasal sinuses.

Fig. 20-34 Correct rotation clearly showing optic canal (arrow).

300

With the exception of paranasal si­ nuses, which should be radiographed up­ right, the remaining radiographic posi­ tions are shown with the patient either upright or recumbent. Comparable radi­ ographs can usuall y be obtained with the patient either upright or recumbent. For example, a recumbent skull radiograph can also be obtained with the patient up­ right as long as the OML and central ray angulation remain constant. Therefore, unless specifically noted i n the text, the photographic i l l ustration does not consti­ tute a recommendation for performi ng the examination with the patient in either the upright or recumbent position. Line draw­ i ngs illustrating both table and upright ra­ diography are included for most radio­ graphic positions in this chapter.

Fig. 20-35 Incorrect rotation for optic canal (arrow).

Technical Considerations GENERAL BODY POSITION The position of the body is important in radiography of the sku l l . Uncomfortable body position resulting in rotation or other motion is re ponsible for the majority of repeat examinations. The radiographers, engrossed in adj usting the patient's head, may forget that the head is attached to a body. If the body is not correctly adjusted, it places so great a strain on the muscles that they cannot support the position. This is especially true when recumbent posi­ tions are used for skull radiography. Some guideli nes to alleviate train and facilitate accurate positioning are provided.

To prevent lateral rotation of the head, place the patient's body so that its long axis, depending on the i mage, either co­ incides with or is parallel to the midline of the radiographic table. To prevent su­ perior or inferior pull on the head, re­ sulting in longitudinal angulation or tilt, place the patient's body so that the long axis of the cervical vertebrae coin­ cides w ith the level of the midpoint of the foramen magnum. Support any elevated part, such as the patient's shoulder or hip, on a pil low or sandbags to rel ieve strain. • For examinations of hyposthenic or as­ thenic patients, elevate the patient's chest on a small pil low to raise the cer­ vical vertebrae to the correct level for the lateral, PA, and oblique projections when the patient is recumbent.

•

• For examinations of obese or hyper­

•

sthenic patients, elevate the patient's head on a radioparent pad to obtain the correct part-I R relationship if needed. An advantage of a head unit is that it simplifies the handling of these patients. While adj usting the body, stand in a po­ sition that facil itates estimation of the approxi mate part po ition. For exam­ ple, stand so that the longitudinal axis of the radiographic table is visible as the midsagittal plane of the body is be­ i ng centered. This allows the anterior surface of the forehead to be viewed while the degree of body rotation for a lateral projection of the skull is ad­ j usted. Therefore the body can be ad­ j usted in such a way that it does not in­ terfere with the final adjustment of the head, and the final position is comfort­ able for the patient.

30 1

When the body is correctly placed and ad­ justed so that the long axis of the cervical vertebrae is suppolted at the level of the fora­ men magnum, the final position of the head requires only minor adjustments. The aver­ age patient can maintain this relatively com­ fortable position without the aid of elaborate immobilization device , although the follow­ ing techniques may be helpful: • If necessary, apply a head clamp with equal pressure on the two ides of the head. • I f such a clamp is not avai lable, use a strip of adhesive tape where it will not be projected onto the image. The por­ tion of the tape touching the hair should have the adhesive side covered with a second piece of tape so that the hairs are not pul led out when the tape is re­ moved. Do not place adhesive tape di­ rectly on the patient's ski n. • When the area to be exposed is small, immobi lize the head with sandbags placed against the sides or vertex. Correct basic body positions and compensatory adjustments for recumbent radi­ ography are illustrated in Figs. 20-36 to 20-43.

CLEANLIN ESS The hair and face are naturally oily and leave a residue, even with the most hy­ gienic patients. If the patient is sick, the residue is worse. During positioning of the skul l , the patient's hair, mouth, nose, and eyes come in direct contact with the vertical glid device, tabletop, or J R. For medical asepsis, a paper towel or a cloth sheet may be placed between the i maging surface and the patient. As part of stan­ dard procedure the contacted area should be cleaned with a disinfectant before and after positioning.

Skull Projections Removed-Ninth Edition Advances in computed tomography (CT) have virtually eliminated many projec­ tions of the kull. The projection elimi­ nated from this chapter may be reviewed in their entirety in the eighth edition and all previous editions of this atlas. The four deleted projections are as follows: Cranial base • Axiolateral projection: Lysholm method Sella turcica

Radiation Protection Protection of the patient from unnecessary radiation is a professional responsibility of the radiographer (see Chapters I and 2 for specific guidelines). I n this chapter, radia­ tion shielding of the patient is not specified or ill ustrated. The federal government has reported that placing a lead shield over a patient's pelvis does not significantly re­ duce gonadal exposure during i maging of the skul l . ] However, lead shields should be used to reassure the patient. Infants and chi ldren shou ld receive ra­ diation shielding of the thyroid and thy­ mus glands and the gonads. The protective lead shielding used to cover the thyroid and thymus glands can also assist in im­ mobi lizing the pediatric patient. The most effective way to protect the patient from unnecessary radiation is to restrict the radiation beam by using proper col limation. Taking care to ensure that the patient is properly instructed and i mmobi­ lized also reduces the l ikelihood of having to repeat the procedure, thereby further limiting the radiation exposure received by the patient.

• PA axial projection: Haas method (com­

bined with Haas method of cranium) Optic canal (foramen) • Orbitoparietal oblique projection: Alex­

ander method Optic canal, superior orbital sulcus, and anterior clinoid process • Parietoorbital axial oblique projection:

modified Lysholm method

Skull Projections Removed-Tenth Edition As a result of advance in computed tomo­ graph (CT), the fol lowing two projections were removed from this edition of the at­ las. These projections may be reviewed in the ninth and all previous editions. Cranium, sella turCica, and ear • PA axial, Valdini Method Sphenoid Strut • Parietoorbital oblique, Hough Method

' H EW 76-80 1 3 Handbook of Selecled Organ Doses.

A

B

..------

302

Fig. 20-36 Horizontal sagittal plane (dashed lines).

Fig. 20-37 Adjusting the sagittal planes to horizontal position. A, Asthenic or hyposthenic patient. B, Angulation corrected.

B

A

Fig. 20-38 Horizontal sagittal plane.

Fig. 20-39 Adjusting the sagittal plane to horizontal position. A, Hypersthenic pa­ tient. B, Angulation corrected.

B

Fig. 20-40 Perpendicular sagittal plane (dashed lines).

Fig. 20-41 Adjusting the OML to vertical position. A, Hypersthenic or round-shoul­ dered patient. B, Angulation corrected.

B

Fig. 20-42 Perpendicular sagittal plane (dashed lines).

Fig. 20-43 Adjusting the OML to vertical position. A, Correction for hyposthenic patient. B, Correction for hypersthenic patient.

303

Cranium

,. LATERAL PROJECTION R o r L position

Position of part

Central ray

• With the side of interest closest to the

• Perpendicular, to enter 2 inches (5 cm)

Image receptor: 24 X 30 cm cross­

wise Position of patient • Place the patient in the seated-upright

•

or semiprone position. • I f a semi prone position is u ed, have

the patient rest on the forearm and flexed knee of the elevated side. •

•

• •

JR, place one hand under the mandibu­ l ar region and the opposite hand on the upper parietal region of the patient's head to help guide it into a true lateral position. Adjust the patient's head so that the midsagittal plane is parallel to the plane of the IR. If necessary, place a support under the side of the mandible to pre­ vent it from sagging. Adjust the flexion of the patient's neck so that the IOML is perpendicular to the front edge of the J R . The JOML also should be parallel to the long axis of the IR. Check the head position so that the in­ terpupi l lary l ine is perpendicular to the IR (Figs. 20-44 to 20-47). Immobilize the head. Respiration: Suspend.

superior to the .EAM . • Center the I R to the central ray. Structures shown

This lateral image of the superimposed halves of the cranium shows the detail of the side adjacent to the lR. The sella tur­ cica, anterior clinoid processes, dorsum sellae, and posterior clinoid processes are well demonstrated in the lateral projection.

Fig. 20-44 Lateral skull.

C.R.

Fig. 20-45 Table radiography. 304

Cranium

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Entire cranium without rotation or tilt • S uperimposed orbital roofs and greater wings of sphenoid • S uperim posed mastoid regions and EAMs • S uperimposed TMJ s • Sella turcica seen i n profi le • Radiographic penetration of parietal region • No overlap of cervical spine by mandible

Fig. 20-46 Lateral skull centered over sella turcica.

1tt-....+.t\" ... '1--#--< C.R.

Fig. 20-47 Upright radiography.

305

Cranium

.. LATERAL PROJECTION

R or L position • Dorsal decubitus

•

•

•

•

With the patient supine, adjust the shoulders to lie in the same horizontal plane. After ruling out cervical injury, place the side of interest closest to the verti­ cally placed grid IR. Elevate the pa­ tient's head enough to center it to the IR, and then support it on a radiolucent sponge. Adjust the patient's head so that the midsagittal plane is vertical and the in­ terpupi llary l ine is perpendicular to the IR (Fig. 20-48). Direct the central ray perpendicular to the I R and center it 2 inches (S cm) su­ perior to the EAM . Robinson, Meares, and Goree 1 recom­ mended using the dorsal decubitus lat­ eral projection for the demonstration of traumatic sphenoid sinus effusion (Fig. 20-49). They stated that this fi nding may be the only clue to the presence of a basal skull fracture.

Structures shown

Supine lateral

Dorsal decubitus or supine lateral position

• •

•

Place the patient in a supine or emi­ supine po ition, and turn the head to­ ward the side being examined. Elevate and support the opposi te shoulder and hip enough that the mid­ sagittal plane of the head is parallel and the interpupi llary line is perpen­ dicular to the I R . Support the patient's head with a radi­ olucent sponge. Direct the central ray perpendicular to enter 2 inches (S cm) superior to the EAM (Fig. 20-S0). Center the IR to the central ray.

This lateral image of the superimposed hal ves of the cranium shows the detail of the side adjacent to the I R . The sella turcica, anterior clinoid processes, dor­ sum sellae, and posterior clinoid pro­ cesses are well demonstrated in the lat­ eral projection (Fig. 20-S 1 ).

' Robinson AE. Meares BM. Goree JA: Traumatic sphenoid sinus effusion. AJR 1 0 1 :795, 1 967.

- -----Fig. 20-48 Dorsal decubitus lateral skull.

- ..--Fig. 20-49 Dorsal decubitus lateral skull showing sphenoid sinus effusion (arrows).

306

(::'-'

,

f'�

Fig, 20-50 Lateral skull with patient supine.

Cranium

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Entire cranium without rotation or tilt • Superimposed orbital roofs and greater wi ngs of sphenoid • S uperimposed mastoid regions and EAMs • SupeJimposed TMJ s • Sella turcica seen in profile • Radiographic penetration of parietal region • No overlap of cervical spine by mandible

Coronal suture

Orbital roof Sella turcica

A Sphenoidal sinus Petrous portion of temporal bone Temporomandibular joint External acoustic meatus Mandibular rami

B

Fig. 20-51 A, Lateral skull. B, Lateral skull showing surgical removal of the frontal bone.

307

Cranium

.. PA PROJECTION .. PA AXIAL PROJECTION

Position of part

Central ray

• Adj ust the flexion of the patient's neck

• For the PA projection, when the frontal

so that the OML is perpendicular to the plane of the I R . If the patient is recumbent, support the chin on a radiolucent sponge if needed. If the patient is obese or hypersthenic, a small radiolucent sponge may need to be placed under (or in front of) the forehead. Align the mjdsagittal plane perpendicu­ lar to the I R . This is accomplished by adj usting the lateral margins of the or­ bits or the EAMs equidistant from the tabletop. I mmobil ize the patient's head, and cen­ ter the IR to the nasion ( Figs. 20-52 to 20-55). Respiration: Suspend.

bone is of primary interest, direct the cen­ tral ray perpendjcular to exjt the nasion. • For the Caldwell method, direct the central ray to exit the nasion at an angle of 1 5 degrees caudad. • Center the I R to the central ray. For demonstration of the superior or­ bital fissures, direct the central ray through the rrudorbits at an angle of 20 to 25 degrees caudad. • For demonstration of the rotundum foramina, direct the central ray to the nasion at an angle of 25 to 30 degrees caudad. (The Waters method is also used for demonstration of the rotundum foramina; ee Chapter 22.)

CALDWELL METHOD • I mage receptor: 24

x

30 cm

lengthwise

•

Position of patient • Place the patient in either a prone or

seated position. Center the midsagittal plane of the pa­ tient's body to the midline of the grid. • Rest the patient 's forehead and nose on the table or against the upright B ucky. • Flex the patient's elbows, place the arms in a comfortable position.

•

•

•

•

308

•

Cranium

Fig. 20-52 PA skull: central ray angulation o f 0 degrees for frontal bone.

Fig. 20-53 PA axial skull: Caldwell method with central ray angu­ lation of 1 5 degrees.

C.R.

Fig. 20-54 Table radiography: Caldwell method.

Fig. 20-55 Upright radiography: Caldwell method.

309

Cranium

Frontal sinus Dorsum sellae Superior orbital margin

Petrous ridge Ethmoidal sinus Inferior orbital margin

Crista galll

Fig. 20-56 PA skull with D-degree central ray angulation.

Frontal sinus

Crista galli Superior orbital margin

Superior orbital fissure Ethmoidal sinus

Petrous ridge Inferior orbital margin

Fig. 20-57 PA axial skull: Caldwell method with caudal central ray angulation of 1 5 degrees.

310

Cranium

Structures shown

Stretcher and bedside examinations

For the PA projection with a perpendicu­ lar central ray (Fig. 20-56), the orbits are fi l led by the margins of the petrous pyra­ mids. Other structures demonstrated in­ clude the posterior ethmoidal air cells, crista gal l i , frontal bone, and frontal si­ nuses. The dorsum sellae is seen as a curved line extending between the orbits, just above the ethmoidal air cells. When the central ray i s angled 1 5 de­ grees caudad to the nasion for the Caldwell method, many of the same struc­ tures that appear in the direct PA projec­ tion are seen (Fig. 20-57). The petrous ridges, however, are projected into the lower third of the orbits. The Caldwell method also demonstrates the anterior eth­ moidal air cells. Schuller, 1 who first decribed this positioning for the skull, rec­ ommended a caudal angle of 25 degrees.

Lateral decubitus position • When the patient cannot be turned to

the prone position for the PA Caldwell projection and cervical spinal injury has been ruled out, elevate one side enough to place the patient's head in a true lateral position and support the shoulder and hip on pi llows or sand­ bags if needed. • Elevate the patient's head on a suitable support, and adj ust its height to center the midsagittal plane of the head to a vertically positioned grid. • Adjust the patient's head so that the OML is perpendicular to the plane of the IR (Fig. 20-58). • Direct the horizontal central ray per­ pendicular, or 1 5 degrees caudad, to exit the nasion.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Entire cranial perimeter showing three disti nct tables of squamous bone • Equal distance from lateral border of skull to lateral border of orbit on both sides • Symmetric petrous ridges • Petrous pyramids lying in lower third of orbit with a caudal central ray angUla­ tion of 1 5 degrees and fill ing the orbits with O-degree central ray angulation • Penetration of frontal bone without excessive density at lateral borders of skull

'SchUller A: Die Schadelbasis i lll Rontgenbild, For/sehr Roen/gens/r : 2 1 5, 1 905.

II

---

.

Fig. 20-58 PA skull with patient semisupine.

31 1

Cranium

Central ray

.. AP PROJECTION

•

.. AP AXIAL PROJECTION Image receptor: 24

x

30 em

•

Perpendicular ( Fig. 20-59) or directed to the nasion at an angle of 1 5 degrees cephalad ( Fig. 20-60). Center the I R to the central ray.

lengthwise Structures shown

When the patient cannot be positioned for a PA or PA axial projection, a similar but somewhat magnified i mage can be ob­ tained with an AP projection. Position of patient and part •

•

31 2

Position the patient supine with the midsagittal plane of the body centered to the grid. Make certa i n that the m idsagittal plane and the OML are perpendicu lar to the J R .

The structures shown on the AP projec­ tion are the same as those demonstrated on the PA projection. On the AP projec­ tion ( Fig. 20-6 1 ), the orbits are consider­ ably magnified because of the increased object-to-image receptor distance (OID). Simi larly, because of the magnification, the distance from the lateral margin of the orbit to the lateral margin of the temporal bone measures less on the AP projection than on the PA projection because of the magnification.

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Entire cranial perimeter showing three distinct areas of squamous bone • Equal distance from lateral border of skull to lateral border of orbit on both sides • Symmetric petrous ridges • Petrous pyramids lying in lower third of orbit with a cephalad central ray angu­ lation of 1 5 degrees and filling orbits with a O-degree central ray angulation • Penetration of frontal bone without ex­ cessive density at lateral borders of skull

Cranium

Fig. 20-59 A P skull.

Fig. 20-60 AP axial skull with 1 5-degree cephalad central ray.

Fig. 20-61 AP skull with O-degree central ray angulation.

3 13

Cranium

.. AP AXIAL PROJECTION TOWN E M ETHOD Image receptor: 24

Position of part

With the patient either supine or seated upright, center the midsagittal plane of the patient's body to the midl ine of the grid. • Place the patient's arms in a comfort­ able position, and adjust the shoulders to lie in the same horizontal plane. • To ensure the patient's comfort without increasing the image receptor distance, examine the hypersthenic or obese pa­ tient in the seated-upright position if possible. • The skull can be brought closer to the IR by having the patient lean back 1 01'­ dotically and rest the shoulders against the vertical grid device. When this is not possible, the desired projection of the occipito-basal region may be ob­ tained by using the PA axial projection described by Haas (page 320). The Haas method is the reverse of the AP axial projection and produces a compa­ rable result.

• Adjust the patient's head so that the

•

x

30 cm

lengthwise NOTE: Although this technique is most com­ monly referred to as the Towne method' nu­ merous authors have described slightly differ­ ent variations. In 1 9 1 2 Grashey2 publ ished the first description of the AP axial projection of the cranium. In 1 926 Altschu(3 and Towne ' de­ scribed the position. Altschul recommended strong depression of the chin and direction of the central ray through the foramen magnum at a caudal angle of 40 degrees. Towne (citing Chamberlain) recommended that with the pa­ tient's chin depressed. the central ray should be directed through the midsagittal plane from a point about 3 inches ( 7 . 6 cm) above the eye­ brows to the foramen magnum. Towne gave no specific central ray angulation, but the angula­ tion would, of course. depend on the flexion of the neck. 'Towne EB: Erosion of the petrous bone by acoustic nerve tumor. Arch Orolal�YlIgol 4:5 1 5 , 1 926. 2Grashey R : Atlas typischer Rtintgenbilder vom nor­ malcn Menschen. In Lehlllallll 's lIIeddllische Allalllell. ed 2, vol 5, Munich. 1 9 1 2. JF Lehmanll. ' A ltschu l W: Beitrag zur Rtintgellologie des Gehtirorganes. Z Hals Nas Ohr 1 4:335. 1 926.

314

Position of patient

•

•

•

•

• •

midsagittal plane is perpendicular to the midline of the I R . Flex the patient's neck enough to place the OML perpendicular to the plane of the IR. When the patient cannot flex the neck to this extent, adjust the neck so that the IOML is perpendicular and then in­ crease the central ray angulation by 7 degrees ( Figs. 20-62 to 20-65 ). Position the IR so that its upper margin is at the level of the highest point of the cranial vertex. This will place the cen­ ter at or near the level of the foramen magnum. For a localized i mage of the dorsum sellae and petrous pyramids, adjust the IR so that its midpoint coincides with the central ray. This means that the I R is centered at or slightly below the level of the occlusal plane. Recheck the position and immobil ize the head. Respiration: Suspend.

Cranium

Fig. 20-62 A P axial skull: Towne method.

Fig. 20-63 AP axial skull: Towne method.

-._�C.R. -,_--7--.:C.R.

Fig. 20-64 Upright radiography. Same radiographic result with central ray directed 30 de­ grees to OML or 37 degrees to IOML.

C.R.

C.R.

Fig. 20-65 Table radiography.

315

Cranium

Central ray

Structures shown

• Directed through the foramen magnum

The AP axial projection shows a symmet­ ric i mage of the petrous pyramids, the pos­ terior portion of the foramen magnum, the dorsum sellae and posterior c l i noid processes projected within the foramen magnum, the occipital bone, and the pos­ terior portion of the parietal bones (Fig. 20-66). This projection is also used for to­ mographic studies of the ears, facial canal, jugular foramina, and rotundum foramina.

at a caudal angle of 30 degrees to the OML or 37 degrees to the IOML. The central ray enters approximately 2 1/2 inches (6.3 cm) above the glabella and passes through the level of the EAM.

316

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Equal distance from lateral border of skull to lateral margin of foramen mag­ num on both sides, indicating no rotation • Symmetric petrous pyramids • Dorsum sellae and posterior clinoid processes visible within foramen mag­ num • Penetration of occipital bone without excessive density at lateral borders of skull

Cranium

Parietal bone

Occipital bone Foramen magnum Petrous ridge Posterior clinoid process Dorsum sellae

Fig. 20-66 AP axial skull: Towne method with 3D-degree central ray angulation to OML.

317

Cranium

Pathologic condition o r trauma

lateral dec ubitus position

For demonstration of the entire foramen magnum, the caudal angulation of the central ray is increased from 40 to 60 de­ grees to the OML (Figs. 20-67 to 20-7 1 ).

For pathologic conditions, trauma, or a de­ formity such as a strongly accentuated dor­ sal kyphosis when the patient cannot be ex­ amined in a direct supine or prone position, the following steps should be observed: • Adj ust and support the body in a semj­ recumbent position; this allows the head to be placed in a true lateral position.

Fig. 20-67 AP axial skull. Towne method, on a trauma patient. Note that the OML and IOML lines are not perpendicular, which would require a central ray angulation greater than 37 degrees.

• I mmobi lize the IR and grid in a vertical

position behind the patient's occiput. • Direct the horizontal central ray 30 de­

grees caudally to the OML (Fig. 20-72).

Fig, 20-68 AP axial skull: central ray angulation of 40 to 45 degrees.

Occipital bone Foramen magnum Petrous ridge Posterior arch C 1 Mandibular condyle

Fig. 20-69 AP axial skull: central ray angulation of 45 degrees.

318

Cranium

Fig. 20-70 A P axial foramen magnum.

Posterior arch of C l Dens

Fig. 20-71 AP axial foramen magnum: central ray angulation of 55 degrees.

Fig. 20-72 AP axial skull, with patient's head in lateral decubitus position and the IR and grid vertical.

319

Cranium

.. PA AXIAL PROJECTION HAAS METHOD Haas ' devised this projection for obtain­ ing an i mage of the sellar structures pro­ jected within the foramen magnum on hy­ persthenic, obese, or other patients who cannot be adj usted correctly for the AP axial (Towne) projection. Image receptor: 24 x 30 cm length­

wise Position of patient

•

Adj ust the patient in the prone or seated-upright position, and center the midsagittal plane of the body to the midline of the grid. Flex the patient's elbows, place the arms in a comfortable position, and ad­ just the shoulders to l ie in the same hor­ izontal plane.

Position of part •

Fig. 20-73 PA axial skull: Haas method. •

•

C.R.

•

•

Rest the patient's forehead and nose on the table, with the midsagittal plane perpendicular to the midline of the grid. Adj ust the flexion of the neck so that the OML is perpendicular to the I R (Figs. 20-73 t o 20-75). Immobilize the head. For a local ized i mage of the sellar re­ gion and/or the petrous pyramids, ad­ just the position of the IR so that the midpoint will coincide with the central ray; shift the I R cephalad approxi­ mately 3 inches (7.6 cm) to include the vertex of the skul l . An 1 8 X 24 cm (8 X 1 0 inch) I R is recommended. Respiration.: S uspend.

' H aas L: Verfahren zur sagittalen Aufnahme der Sellagegend, Forlschr Roelllgellslr 36: 1 1 98, 1 927.

--L

�C.R.

-

Fig. 20-74 Upright radiography.

320

Fig. 20-75 Table radiography.

Cranium

Central ray • Directed at a cephalad angle of 25 de­ grees to enter a point I Y2 inches (3.8

cm) below the external occipital protu­ berance ( inion) and to exit approxi­ mately I � inches (3.8 cm) superior to the na ion. The central ray can be varied to demonstrate other cranial anatomy.

Structures shown

A PA axial projection demonstrates the occipital region of the cranium and shows a symmetric image of the petrous pyra­ mids and the dorsum sellae and posterior cl inoid processes within the foramen magnum (Figs. 20-76 and 20-77).

Occipital bone

Foramen magnum

Petrous ridge

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Projection of dorsum sellae and poste­ rior clinoid processes within foramen magnum • Equal distance from lateral border of kull to lateral margin of foramen mag­ num on both sides, indicating no rotation • Symmetric petrous pyramids • Entire cranium

Posterior clinoid process Dorsum sellae Sphenoidal sinus Fig. 20-76 PA axial skull: Haas method, with central ray angulation of 25 degrees.

Foramen magnum

Petrous ridge Mastoid air cells Posterior clinoid process

Dorsum sellae

Fig. 20-77 PA axial sella turcica: Haas method, using a cylindric extension cone that re­ stricts collimation to a small area. Beam restriction decreases scatter radiation and in­ creases the visibility of detail of the sellar structures.

32 1

Cranial Base

.. SUBMENTOVERTICAl PROJECTION

•

SCH U LLER METHOD Image receptor: 24

x

30 cm

lengthwi e Position of patient

The success of the submentovertical (SMV) projection of the cranial base depends on plac­ ing the IOML as nearly parallel with the plane of the IR as possible and directing the central ray perpendicular to the IOML. The following steps are observed:

•

Place the patient in the supine or the seated-upright position; the latter is more comfortable. If a chair that up­ ports the back is used, the upright posi­ tion also allows greater freedom in po­ sitioning the patient's body to place the IOML parallel with the I R . If the pa­ tient is seated far enough away from the vertical grid device, the head can usu­ ally be adjusted without placing great pressure on the neck. When the patient is placed in the supine position, elevate the torso on firm pil­ lows or a suitable pad to allow the head to rest on the vertex with the neck in hyperextension.

Flex the patient's knees to relax the ab­ dom inal muscles. • Place the patient's arms in a comfort­ able position, and adjust the shoulders to lie in the same horizontal plane. Do not keep the patient in the final ad­ justment longer than is ab olutely nec­ essary because the supine position places considerable strain on the neck.

•

•

Position of part •

•

With the midsagittal plane of the pa­ tient's body centered to the midline of the grid, extend the patient's neck to the greatest extent as can be achieved, plac­ i ng the IOML as parallel as possible to the IR. Adjust the patient's head 0 that the midsagittal plane is perpendicular to the I R (Figs. 20-78 to 20-8 1 ) .

NOTE: Patients placed in the supine position for the cranial base may have increased in­ tracranial pressure. As a result, they may be dizzy or unstable for a few minutes after hav­ ing been in this position. Use of the upright po­ sition may alleviate some of this pressure.

LL-----\od�-'------_
Fig. 20-78 SMV cranial base.

Fig. 20-79 Upright radiography.

C.R.

Fig. 20-80 SMV cranial base.

322

Fig. 20-81 Table radiography.

Cranial Base

• I mmobilize the patient's head. In the

Structures shown

absence of a head clamp, place a suit­ ably backed strip of adhesive tape acros the tip of the chin and anchor it to the sides of the radiographic unit i f needed. (The part o f the tape touching the skin should be covered. ) Respiration: Suspend.

An SMV projection of the cranial base demonstrates symmetric i mages of the petrosae, the mastoid processes, the forarru na ovale and spinosum (which are best shown i n this projection), the carotid canals, the sphenoidal and ethmoidal si­ nuses, the mandible, the bony nasal sep­ tum, the dens of the axis, and the occipital bone. The maxillary sinuses are superim­ posed over the mandible (Fig. 20-82). The SMV projection i s also used for axial tomography of the orbits, optic canals, ethmoid bone, maxillary si nuses, and mastoid processes. With a decrease i n the exposure factors the zygomatic arches are also well demonstrated in this position (see Chapter 22).

Central ray • Directed through the ella turcica per­

pendicular to the IOML. The central ray enters the midsagittal plane of the throat between the angles of the mandible and passes through a point % inch ( 1 .9 cm) anterior to the level of the EAMs. • Center the l R to the central ray. The I R should be parallel to the IOML.

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Clearly visible structures of the cranial base, indicated by adequate penetration • Equal distance from lateral border of skull to mandibular condyles on both sides, indicating no tilt. • Superimposition of mental protuber­ ance over anterior frontal bone, i ndicat­ ing full extension of neck • Mandibular condyles anterior to petrous pyrarruds • Symmetric petrosae NOTE: SchUl ler' described and illustrated the basal projections-submentovertical and verti­ cosubmental ( VS M)-but Pfeiffer' gave spe­ cific directions for the central ray angulation. ' SchUller A: Die Schadel basis im Rontgenbild, 1 :2 1 S . 1 905. 'Pfeiffer W: Beitrag zum Wert des axialen Schadelskiagrammes, Arch Laryngol Rhinol 30: I , 1 9 1 6. Forlshr Reonlgenslr 1

Maxillary sinus

Ethmoidal air cells Mandible Sphenoidal sinus Foramen splnosum Mandibular condyle Dens (odontoid process) Petrosa Mastoid process Occipital bone

Fig. 20-82 SMV cranial base.

323

Cranial Base

VERTICOSUBME NTAl PROJECTION SCH U LLER METHOD Image receptor: 24 x 30 cm length­

wise The verticosubmental (VSM) projection is used to demonstrate the base of the cra­ nium when the SMV projection is con­ trai ndicated by the patient's condition. Position of patient

Position of part • Rest the patient's fully extended chin

on the table, and adjust it so that the midsagittal plane is perpendicular to the IR (Fig. 20-83). I mmobilize the patient's head. • Respiration: Suspend. Central ray • Directed through the sella turcica per­

pendicular to the IOML. The central ray passes through a point % inch ( 1 .9 cm) anterior to the level of the EAMs.

• Place the patient in the prone position,

and center the mjdsagittal plane of the body to the rrtidline of the grid. • Flex the patient's elbows, place the arms in a comfortable position, and ad­ just the shoulders to l ie in the same hor­ izontal plane.

Fig. 20-83 VSM cranial base.

324

Structures shown

The VSM projection ( Fig. 20-84) of the cranial base is somewhat similar to the SMV projection . Because of the i ncrease in OlD and the increase in the angle be­ tween the cranial base and the plane of the J R, the basal structures, particularly those in the midbase region, are somewhat dis­ torted and magnified. However, this pro­ jection is useful in studies of the anterior cranial base and sphenoidal sinuses, for which magnification and distortion can be reduced by placing the I R in contact with the throat.

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Structures of cranial base • Equal distance from lateral border of skull to mandibular condyles on both sides, indicating no tilt of head • Mandibular condyles anterior to petrous pyramids • Symmetric petrosae • Superimposition of mental protuber­ ance over anterior frontal bone, indicat­ ing that central ray was perpendicular to IOML

Frontal bone and mandible Maxillary sinus Ethmoidal air cells Vomer Sphenoidal sinus Pharynx Foramen splnosum Mandibular condyle Mastoid air cells

Fig. 20-84 VSM cranial base.

325

Sella Tu rcica

'"

LATERAL PROJECTION R or L position Image receptor: 8 x 1 0 inch ( 1 8 x

24 cm) A closely col limated projection of the sella turcica is often requested in addition to the lateral projection of the entire cranium. Position of patient • Place the patient in the seated-upright

or semiprone position. • Adjust the rotation of the patient's body

so that the m idsagittal plane of the head is parallel to the plane of the IR. A hy­ persthenic or obese patient in the semi­ prone position may require a radiolu­ cent sponge support under the head.

Fig. 20-85 Lateral skull for sella turcica.

Position of part • Adjust the patient's head in a true lat­

•

• • C.R. Fig. 20-86 Upright radiography.

C.R.

Fig. 20-87 Table radiography.

326

•

eral position so that the midsagittal plane is paral lel with the plane of the I R and the interpupillary line is perpendic­ ular to the IR plane. Adjust the patient's head so that the IOML is parallel with the transverse axi of the lR (Figs. 20-85 to 20-87). I mmobi l i ze the patient ' s head as necessary. Center the IR to the region of the sella turcica, a point % inch ( 1 .9 cm) anterior and % i nch ( 1 .9 cm) superior to the EAM. Respiration: S uspend.

Sella Tu rcica

EVALUATION CRITERIA

Central ray • Perpendicular to the center of the I R at a point % i nch ( 1 .9 cm) anterior and % inch ( 1 .9 cm) superior to the EAM . • Colli mate t o the sphenoid bone. Structures shown

The i mage shows a lateral projection of the seUar region of the crani um (Fig. 20-88).

The fol lowing should be clearly demon­ strated: • No rotation or distortion of sella turcica • Superimposed anterior clinoid processes • Superimposed posterior clinoid processes • Sella turcica centered on radiograph • Close beam restriction of sellar region

Anterior clinoid

Posterior clinoid Dorsum sellae Sella turcica Sphenoidal sinus

Fig. 20-88 Lateral sella turcica.

327

Sella Turcica, Dorsum Sellae, and Posterior Clinoid Processes

AP AXIAL PROJECTION Image receptor: 8 x 10 inch ( 1 8 x

24 cm) lengthwise Position of patient • With the patient seated upright or

supine, center the midsagittal plane of the body to the midline of the grid. • Place the patient's arms alongside the body, and adjust the shoulders to lie in the same horizontal plane.

Position of part

Central ray

• With the midsagittal plane centered and

• Directed to the midsagittal plane, enter­

perpendicular to the midline of the grid, adjust the flexion of the patient's neck so that the IOML is perpendicular to the plane of the IR (Figs. 20-89 to 20-9 1 ). • I mmobilize the head. • Respiration: Suspend.

ing the upper forehead and passing through the head at the level of the EAM: I . A 37-degree caudal angulation pro­ jects the dorsum sellae and posterior clinoid processe within the fora­ men magnum (Fig. 20-92). 2. A 30-degree caudal angulation of the central ray to the IOML projects the dorsum and tuberculum sellae and the anterior clinoid processes through the occipital bone above the level of the foramen magnum (Fig. 20-93). 3 . Adjust the I R so that its midpoint coincides with the central ray. Structures shown

AP axial images of the sellar region and petrous pyramids are demonstrated.

Fig. 20-89 AP axial sella turcica.

C.R. --,,---+C. R.

Fig. 20-90 Upright radiography.

328

Fig. 20-91 Table radiography.

Sella Turcica, Dorsum Sellae, and Posterior Clinoid Processes

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Sel lar structures within foramen mag­ num with a 37-degree angulation • Sellar structures through occipital bone with a 30-degree angulation • No rotation of cranium • Symmetric petrous pyramids • Close beam restriction of sellar region

Occipital bone Foramen magnum

Petrous ridge Posterior clinoid

Dorsum sellae

Fig. 20-92 AP axial sella turcica: 37-degree central ray angulation.

Orbit

Occipital bone

Anterior clinoid Petrous ridge Sphenoidal sinus Sphenoidal sinus

Fig. 20-93 AP axial sella turcica: 30-degree central ray angulation.

329

Sella Turcica, Dorsum Sellae, and Posterior Clinoid Processes

PA AXIAL PROJECTION Image receptor: 8 x 1 0 inch ( 1 8 x

24 cm) lengthwise Position of patient o

o

o

With the patient in the prone or seated position, center the midsagittal plane of the body to the midline of the grid. Flex the patient's elbows, place the arms in a comfortable position, and ad­ just the shoulders to lie in the same hor­ izontal plane.

Central ray

Position of part o

o

o o

Rest the patient 's forehead and nose against the upright B ucky, and adjust the head so that the OML is perpendic­ ular to the IR ( Fig. 20-94). Support the patient's chin to prevent angulation if needed. Adj ust the midsagittal plane perpendic­ ular to the IR. I mmobil ize the head. Respiration: Suspend.

o

o

o

Directed to exit the glabella at an angle of 1 0 degrees cephalad. Adjust the position of the IR so that i ts midpoint coincides with the central ray ( Figs. 20-95 and 20-96). Use close collimation.

Fig. 20-94 PA axial sella turcica.

C.R.

'--=-< C.R.

Fig. 20-95 Upright radiography.

330

Fig. 20-96 Table radiography.

Sella Tu rcica, Dorsum Sellae, and Posterior Clinoid Processes

Structures shown

The dor um and tuberculum ellae and the posterior and anterior clinoid processes are projected through the frontal bone just above the ethmoidal si nuses (Fig. 20-97 ).

EVALUATION CRITERIA

The following should be clearly demon­ strated : • Adequate penetration of sellar structures visible through frontal bone • No rotation of cran ium • Symmetric petrous pyramids • Close beam restriction of ellar region

Dorsum sellae Posterior clinoid Anterior clinoid Petrous ridge Supraorbital ridge Ethmoidal sinus

Fig. 20-97 PA axial sella turcica.

331

Orbit The orbits are cone-shaped, bony-walled cavities situated on each side of the mid­ sagittal plane of the head (Fig. 20-98) . They are formed b y the seven previously described and i l l ustrated bones of the cra­ nium (frontal, ethmoid, and sphenoid) and the face (lacrimal, palatine, maxil lary, and zygomatic). Each orbit has a roof, a me­ dial wal l, a lateral wall, and a floor. The easily palpable, quadrilateral-shaped ante­ rior circumference of the orbit is called its base. The apex of the orbit corresponds to the optic foramen. The long axis of each orbit is directed obliquely, posteriorly. and medially at an average angle of 37 degrees to the midsagittal plane of the head and also superiorly at an angle of about 30 de­ grees from the OML (Fig. 20-99).

Fig. 20-98 Bones of left orbit of dry specimen. A, Optic canal and foramen. B, Superior or­ bital fissure. C, Inferior orbital fissure; E Ethmoid; F, frontal; L lacrimal; M maxilla; S, sphe­ noid; l zygomatic (palatine not shown).

B

A

Fig. 20-99 Cone-shaped orbit. A, Average angle of 37 degrees from the midsagittal plane. B, Average angle of 30 degrees superior to the OML.

332

The orbits serve pri marily as bony ockets for the eyebal ls and the structures associated with them, but they also con­ tain blood vessels and nerves that pass through openi ngs in their walls to other regions. The major and frequently radi­ ographed openings are the previously de­ scribed optic foramina and the superior and inferior orbital sulci . The superior orbital fissure is the cleft between the greater and lesser wings of the sphenoid bone. From the body of the sphenoid at a point near the orbital apex, this sulcus extends superiorly and later­ ally between the roof and the lateral wall of the orbit. The inferior orbital fissure is the narrow cleft extending from the lower anterolateral aspect of the sphenoid body anteriorly and laterally between the floor and lateral wall of the orbit. The anterior margin of the cleft is formed by the orbital plate of the maxilla, and its posterior mar­ gin is formed by the greater wing of the phenoid bone and the zygomatic bone. Because the walls of the orbits are thjn, they are subject to fracture. For example, when a per on is forcibly struck squarely on the eyeball (by a fist, a piece of sport­ ing equipment, etc . ), the resulti ng pres­ sure directed to the eyeball forces the eye­ bal l i nto the cone-shaped orbit and "blows out" the thin, delicate bony floor of the or­ bit (Figs. 20- 1 00 and 20- 1 0 1 ). The injury must be diagnosed and treated accurately so that the person's vision is not jeopar­ dized. B low-out fractures may be demon­ strated u ing any combination of radi­ ographs obtai ned with the pat ient positioned for parietoacanthial projections ( Waters method), radiographic tomogra­ phy, and/or CT.

Fig. 20- 1 00 Parietoacanthial orbits using Waters method and showing blowout fracture of orbit (arrows).

Fig. 20- 1 0 1 Tomogram: AP projection showing fracture (arrow) in the same patient as in Fig. 20-1 07.

333

Optic Canal and Foramen

.. PARI ETOORBITAL OBLIQUE PROJECTION RHESE M ETHOD Image receptor: 8 x 10 inch ( 1 8 x

24 cm) Position of patient • Place the patient in the semiprone or

eated-upright position. • Place the patient's arms in a comfort­

able position, and adjust the shoulder to lie in the same horizontal plane .

..

� ,

'-'- ::..:�,

Position of part

,

• Center the affected orbit to the unmasked

Fig, 20- 1 02 Parietoorbital oblique projection: Rhese method,

• C,R,

C,R,

•

• •

Fig. 20- 1 03 Table radiography.

____

Ho.Io.,-��---I------< C.R,

53'

�....,,,., __!-_+____< C,R,

Fig. 20- 1 04 Upright radiography.

334

half of the I R, and rest the zygoma, nose, and chin on the radiographic table or against the upright Sucky. Adju t the flexion of the patient's neck to place the AML perpendicular to the plane of the I R . Adj ust the rotation o f the patient's head so that the midsagittal plane forms an angle of 53 degrees to the plane of the IR (Figs. 20- 1 02 to 20- 1 04). A protrac­ tor may be used to obtain an accurate 53-degree angle. Immobi lize the patient's head. Respiration: Su pend.

Optic Canal and Foramen

Central ray

•

•

Structures shown

Perpendicular, entering approximately I inch (2.5 cm) superior and posterior to the upside TEA. The central ray ex­ its through the affected orbit closest to the I R. Coll i mate the beam clo ely to the orbit resting on table. Center the IR to the central ray.

Thi projection demonstrates the optic canal "on end" and the optic foramen lying in the i nferior and lateral quadrant of the projected orbit ( Fig. 20- l OS). Any lateral deviation of this location indicates incor­ rect rotation of the head. Any longitudinal deviation indicates incorrect angulation of the AML. Both sides are exami ned for comparison. A parietoorbital projection of the ethmoidal, sphenoidal, and frontal si nuses is also demonstrated (Fig. 20- 1 06).

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Optic canal and foramen visible at end of sphenoid ridge in inferior and lateral quadrant of orbit • Entire orbital ri m • Supraorbital margins lying in same hor­ izontal li ne • Close beam restriction to the orbital region

Superior orbital margin

Lateral orbital margin Optic canal and foramen Medial orbital margin Lesser wing of sphenoid Ethmoidal sinus

Inferior orbital margin

Fig. 20- 1 05 Parietoorbital oblique projection: Rhese method.

Frontal sinuses Superior orbital margin Orbit Lesser wing of

Maxillary sinuses

Fig. 20- 1 06 Parietoorbital oblique sinuses: Rhese method.

335

Optic Canal and Foramen

.. ORBITOPARIETAL OBLIQUE PROJECTION RHESE METHOD Image receptor: 8 x 10 inch ( 1 8 x

24 cm) Position of patient • With the patient in the seated-upright or

supine position, center the mjdsagittal plane of the body to the midline of the grid. • Place the patient's arms along the s ides of the body and adjust the shoulders to lie in the same horizontal plane. Position of part Fig. 20- 1 07 Orbitoparietal oblique projection: Rhese method.

C.R.

C.R.

\

53°

Fig. 20- 1 08 Table radiography.

D----
I\--��.----+---< C.R.

Fig. 20- 1 09 Upright radiography.

336

)

• Rotate the patient's head so that the

midsagittal plane forms an angle of 53 degrees to the plane of the IR. • Adjust the AML perpendicular to the IR (Figs. 20- 1 07 to 20- 1 09). • Immobi lize the patient's head. • Respiration: S uspend.

Optic Canal and Foramen

Central ray • Perpendicular to enter the uppermost

orbit at its inferior and lateral quadrant. • Center the I R to the central ray. Structures shown

The i mage shows the optic canal "on end" and the optic foramen in the inferior and lateral quadrant of the orbit (Fig. 20- 1 1 0) . This projection, the exact reverse o f the parietoorbital oblique projection de­ scribed previously, produces a compara­ ble i mage.

NOTE: This projection should be used for pa­ tients who cannot be turned to the prone posi­ tion. However, placing the patient supine re­ sults in a certain degree of magnification on the radiograph because of the increased OLD. Furthermore, greater radiation exposure to the lens of the eye occurs with the orbitoparietal oblique projection than with the parietoorbital oblique projection.

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Optic canal and foramen visible at end of sphenoid ridge in inferior and lateral quadrant of orbit • Entire orbital rim • Close beam restriction to the orbital region • Supraorbital margins lying on same horizontal plane

Superior orbital margin Lateral orbital margin

Optic canal and foramen Medial orbital margin Sphenoid ridge Inferior orbital margin

Fig. 20- 1 1 0 Orbitoparietal oblique projection: Rhese method. 337

Superior Orbital Fissures

PA AXIAL PROJECTION Image receptor: 8 x 10 inch ( 1 8 X

24 em) lengthwise Position of patient o

o

Place the patient in the prone or seated­ upright position. Center the midsagittal plane of the pa­ tient's body to the midline of the grid.

Position of part o

o

Fig. 20- 1 1 1 PA axial superior orbital sulcus. o

o

Rest the patient's forehead and nose on the grid device with the midsagittal plane centered and perpendicular to the midline of the I R . Adjust the flexion o f the patient's neck so that the OML is perpendicular to the plane of the IR (Figs. 20- 1 I I to 20- 1 1 3). Center the IR at the level of the inferior margin of the orbits. Respiration: Suspend.

Central ray o

o

Fig. 20- 1 1 2 Table radiography.

_r--\--_,.",t-C . R.

Fig. 20- 1 1 3 Upright radiography.

338

Directed to the midsagittal plane at an angle of 20 to 25 degrees caudad and exiting at the level of the inferior mar­ gin of the orbit. U e close col limation.

Superior Orbital Fissures

Structures shown

The superior margin of the petrous por­ tions of the temporal bones should be pro­ jected at or just below the inferior margin of the orbits (Fig. 20- 1 1 4) . The superior orbital (sphenoid) fissures are seen as elongated dark areas lying on the medial side of the orbits between the greater and lesser wings of the sphenoid bones. The margins of the superior orbital fis­ sures, although somewhat narrowed, are frequently well shown on the I S-degree caudad angle PA axial projection of the skull (Fig. 20- 1 1 5 ).

Lesser wing of sphenoid Greater wing of sphenoid

Superior orbital fissure Petrous ridge �...,....�=

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Symmetric visualization of superior or­ bital fissures, indicating no rotation of cranium • Projection of petrous ridges below su­ perior orbital sulci • Close beam restriction to both orbital regions

Fig. 20- 1 1 4 PA axial superior orbital sulci.

Superior orbital margin

Superior orbital fissure

Petrous ridge

Fig. 20- 1 1 5 PA axial skull: Caldwell method, with central ray an­ gulation of 15 degrees.

339

I nferior O rbital Fissures

PA AXIAL PROJECTION BERTE L METHOD Image receptor: 8 x 1 0 i nch ( 1 8 X 24 cm) lengthwise Position of patient •

•

•

Place the patient in the seated-upright or prone position. Center the midsagittal plane of the pa­ tient's body to the midline of the grid device. Place the patient's arms in a comfort­ able position, and adjust the shoulders to lie in the same horizontal plane.

Position of part Fig. 20- 1 1 6 PA axial projection, Bertel method, for inferior orbital sulci.

• Rest the patient's forehead and nose on

the grid device, with the midsagittal plane perpendicular to the midline of the grid. Adjust the flexion of the patient's neck so that the IOML is perpendicular to the plane of the l R ; elevate the forehead somewhat on a radiolucent pad i f needed (Figs. 20- 1 1 6 t o 20- 1 1 8) . I mmobilize the patient's head. • Respiration: Suspend.

•

•

�

=-
-

Fig. 20- 1 1 7 Upright radiography.

C.R.

Fig. 20- 1 1 8 Table radiography.

340

Inferior Orbital Fissu res

Central ray • Directed at an angle of 20 to 25 degrees

cephalad and exiting the na ion. The central ray enters the midline approxi­ mately 3 inches (7.6 cm) below the ex­ ternal occipital protuberance. • Center the IR to the central ray. NOTE: Decreased exposure factors are typi­ cally u ed because the central ray enters below the cranium. Therefore Ie s penetration is required. Structures shown

Superior orbital margin

A PA axial projection of each orbital floor

and i nferior orbital fissure is demon­ strated between the shadows of the lateral pterygoid lamina of the sphenoid bone and the condylar process of the mandible (Fig. 20- 1 1 9).

Styloid process Inferior orbital fissure

Lateral pterygoid lamina Mandibular ramus

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Symmetric visualization of inferior or­ bital sulci within orbits, indicating no rotation of cranium • Clo e beam restriction to both orbital regions

Nasal cavity

Fig. 20- 1 1 9 PA axial projection, Bertel method, for inferior or­ bital sulci. Note that exposure factors for orbital area are dif­ ferent from those for skull.

34 1

Eye The organ of vision, or eye (Latin, oculus; Greek, aphtha/mas), consists of the fol­ lowing: eyebal l ; the optic nerve, which connects the eyeball to the brain; the blood vessels; and aeee ory organs such as the extrinsic muscle , lacrimal apparatus, and eyelids ( Figs. 20- 1 20 and 20- 1 2 1 ).

The eyeball is situated in the anterior part of the orbital cavity. Its posterior seg­ ment (about two thirds of the bulb) is ad­ jacent to the oft parts that occupy the re­ mainder of the orbital cav ity (chiefly muscles, fat, and connective tissue). The anterior portion of the eyeball is exposed and projects somewhat beyond the base of the orbi t. Therefore bone-free radio­ graphic i mages of the anterior segment of the eye can be obtained. The exposed part of the eyeball is covered by a thin mucous membrane known as the conjunctiva, por­ tions of which l ine the eyelids. The con­ junctival membrane is kept moist by tear secretions from the lacrimal gland. These secretions prevent drying and friction irri­ tation duri ng movements of the eyeball and eyelids.

Conjunctiva Pupil

Zygoma --+-i;-l1-;

Fig. 20-1 20 Diagrammatic horizontal section of right orbital region: top-down view.

342

The outer, supporting coat of the eye­ bal l is a firm, fibrous membrane consist­ ing of a posterior segment called the sclera and an anterior segment called the cornea. The opaque, white sclera is com­ monly referred to as the white of the eye. The cornea is situated in front of the iris, with its center point corresponding to the pupil. The corneal part of the membrane is transparent, al lowing the passage of light into the eyeball, and it serves as one of the four refractive media of the eye.

The inner coat of the eyeball is called the retina. This delicate membrane is con­ tiguous with the optic nerve. The retina is composed chiefly of nervous tissue and several mil lion minute receptor organs, called rods and cones, which transmit light impulses to the brain. The rods and cones are important radiographically because they play a role in the abi lity of the radiol­ ogist, or radiographer, to see the fl uoro­ scopic image. Their function is described in discussions of fluoroscopy in radiogra­ phy physics and imaging textbooks.

Moxillo Fig. 20- 1 2 1 Diagrammatic sagittal section of right orbital region.

343

LOCALIZATION OF FOREIGN BODIES WITH IN ORBIT OR EYE Ultrasonography and CT ( Fig. 20- 1 22) have been increasingly used to locate for­ eign bodies in the eye. ( M agnetic reso­ nance i maging is not used for foreign body localization because movement of a metal l ic foreign object by the magnetic field could lead to hemorrhage or other se­ rious compl ications.) Whether an ultra­ sound or a radiographic approach is used, accurate localization of foreign particles lodged within the orbit or eye requires us­ ing a precision localization technique. Localization methods removed

The Vogt method, Sweet method, Pfeiffer­ Comberg method, and paral lax motion method are sometimes used to localize for­ eign bodies in the eye. These methods were described briefly in the eighth edition of this atlas. Complete descriptions appeared in the seventh and earlier editions.

Image quality

U1trafine recorded detail is essential to the detection and localization of minute for­ eign particles within the orbit or eyeball . The fol lowing are required: I . The geometric un sharpness must be re­ duced as much as possible by the use of a close O l D and a small, undamaged focal spot at a source-to-image recep­ tor distance (SID) that is as long as is consistent with the exposure factors required. 2. Secondary radiation must be mini­ mized by close collimation. 3. Motion must be eliminated by firmly i mmobil izing the patient's head and by having the patient gaze steadily at a fixed object, thereby immobilizing the eyeballs.

An artifact can cast an image that sim­ ulates the appearance of a foreign body located within the orbit or eye. Therefore I Rs and screens must be impeccably clean before each examination. In institutions and clinics that often perform these exam­ inations, an adequate number of IR hold­ ers are held in reserve for eye studies only. This measure protects them from the wear of routine use in less critical procedures.

PRELIMI NARY EXAMINATION Lateral projections, PA projections, and bone-free studies are taken to determine whether a radiographically demonstrable foreign body is present. For these radi­ ographs, the patient may be placed in the recumbent position or may be seated up­ right before a vertical grid device.

B

A

Fig. 20- 1 22 A, Lateral localizer CT image showing multiple buckshot in the face. B, Axial CT image of same patient. showing shotgun pellets within the eye (arrow).

344

Eye

LATERAL PROJECTION R or l position

A nongrid (very high-resolution) tech­ nique is recommended to reduce magnifi­ cation and elimjnate possible artifacts in or on the radiographic table and grid. The fol lowing steps are observed: With the patient either serruprone or seated upright, place the outer canthus of the affected eye adjacent to and cen­ tered over the mjdpoi nt of the IR. Adjust the patient's head to place the m idsagittal plane parallel with the plane of the I R and the interpupil lary line perpendicular to the IR plane. Respiration: Suspend. o

o

o

Central ray o o

Perpendicular through the outer canthus. In truct the patient to look traight ahead for the exposure ( Figs. 20- I 23 and 20- 1 24). Fig. 20- 1 23 Lateral projection for orbital foreign body localization.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Density and contrast perrrutting optimal visibil ity of orbit and eye for localiza­ tion of foreign bodies • Superimposed orbital roofs • Close beam restriction centered to or­ bital region Superior orbital margin

Nasal bone

Fig. 20- 1 24 Lateral projection showing foreign body (white speck).

345

Eye

PA AXIAL PROJECTION A nongrid (very high-resolution ) tech­ nique is recommended to reduce magnifi­ cation and elimi nate possible artifact in or on the radiographic table and grid. The following steps are observed: • Rest the patient's forehead and nose on the IR holder, and center the holder % inch ( 1 .9 cm) distal to the nasion. • Adj ust the patient's head so that the midsagittal plane and the OML are per­ pendicular to the plane of the IR. • Respiration: Suspend. Central ray • Directed through the center of the or­

Fig. 20- 1 25 PA axial projection for orbital foreign body localization.

bits at a caudal angulation of 30 de­ grees. This angulation is used to project the petrous portions of the temporal bones below the i nferior margin of the orbits (Figs. 20- 1 25 and 20- 1 26). • I nstruct the patient to close the eyes and to concentrate on holding them still for the exposure. EVALUATION CRITERIA

The following should be clearly demon­ strated: • Petrous pyramids lying below orbital shadows • No rotation of cranium • Close beam restriction centered to or­ bital region

Fig. 20- 1 26 PA axial projection demonstrating foreign body (arrow) in right eye.

346

Eye

PARIETOACANTHIAL PROJECTION MODIFIED WATERS METHOD Some physicians prefer to have the PA projection performed with the patient's head adjusted in a modified Waters posi­ tion 0 that the petrous margins are dis­ placed by part adjustment rather than by central ray angulation. The fol lowing steps are observed: • With the IR centered at the level of the center of the orbits, rest the patient 's chin on the J R holder. • Adj ust the patient's head so that the midsagittal plane is perpendicular to the plane of the J R . • Adjust the flexion o f the patient's neck so that the OML forms an angle of 50 degrees with the plane of the IR. • Respiration: Suspend.

Fig. 20-1 27 Parietoacanthial projection, modified Waters method, for orbital foreign body localization.

Central ray • Perpendicular through the midorbits

(Figs. 20- 1 27 and 20- 1 28). • I nstruct the patient to close the eyes and

to concentrate on holding them still for the exposure. EVALUATION CRITERIA

The following should be clearly demon­ strated: • Petrous pyramids lying well below or­ bital shadows • Symmetric visual ization of orbits, indi­ cating no rotation of cranium • C lose beam restriction centered to the orbital region

Fig. 20- 1 28 Parietoacanthial projection, modified Waters method, demonstrating foreign body (arrow).

347

Nasolacrimal Drainage System Dacryocystography (Greek dakryon, tear) is the term used to denote radiologic ex­ amination of the nasolacrimal drainage system. The examination is performed by fi lling the lumina of the canals with a ra­ diopaque medium. The examination is used to investigate such abnormalities of these pa sages as defective development, stenosis, and chronic mucosal thickening. The lacrimal gland ( Latin lacri ma, tear) is a small , almond-shaped, bipartite body situated anteriorly on the lateral side of the roof of the orbit, where it is lodged in the lacrimal fossa of the frontal bone (Fig. 20- 1 29). The function of the gland is to secrete watery fl uid. The tear secretion serves to lubricate and wet the delicate membrane that li nes the eyelids and cov­ er the front of the eyeball. This mem­ brane is called the conjunctiva, and the space between the l ids and the surface of the eyeball is called the conjunctival sac. Between 6 and 1 2 mi nute ducts convey the tear secretion from the gland to the conjunctival sac, and the blinking move­ ments of the l ids spread the fluid over the surface of the eyebal l . Part of the fluid evaporates, and part of it flows into the lacrimal lake. The lacrimal lake is the shallow, triangular pouch, or cul-de-sac, that is formed by the conjunctiva at the in­ ner angle, or canthus, of the eye. This pouch is in large part occupied by the lacrimal caruncle, which is the fleshy, red­ dish eminence situated in the inner angle of the eye. The tear secretion that collects in the lacrimal lake is drained into the inferior nasal meatus through the nasolacrimal ystem of ducts. This system of channels is the part of the lacrimal apparatus often subjected to radiologic investigation. The nasolacrimal system of channels consists of two small canals cal led lacrimal canaliculi, one canal iculus leading from the free margin of the inner angle of each eyelid, and the lacrimal sac, which is the upper, rounded, and sl ightly dilated part of the nasolacrimal duct.

Each canaliculus begins at a mi nute ori­ fice called the punctum lacrimale. The punctum lacrimale is situated on a small elevation, the lacrimal papilla, so that it is directed i nto the lacrimal lake for the drainage of accumulating fluid. From its orifice, or punctum, the canal iculus passes within the margin of the respective eyelid, first vertically and then medially, to its junction with the lacrimal sac, for a dis­ tance of about 1 0 mm. The canal iculi sometimes unite i nto a single passage as they converge toward their entrance into the lacrimal sac.

The lacrimal sac is 1 2 mm in length, is rounded above, and is sl ightly constricted at its j unction with the nasolacrimal duct proper. The sac is situated anteroinferiorly on the medial wall of the orbit, where it is lodged in the fossa formed for it by the lacrimal and maxillary bones and on the other side of which are the anterior eth­ moidal air cells. The lacrimal fossa is the beginning of the osseous lacrimal canal, through which the nasolacri mal duct passes. The bony canal is formed by the l acri mal bone, max i l l ary bone, and lacrimal process of the inferior nasal con­ cha. It passes inferiorly, posteriorly, and laterally between the medial wall of the maxil lary sinus and the lateral wall of the nasal cavity. The nasolacrimal duct proper varies in length but is bel ieved to average approxi­ mately 1 7 mm. The duct narrows some­ what as it approaches the nasal cavity, where it opens under the i nferior concha approximately in l ine with the first molar tooth.

Lacrimal gland

Superior canaliculus Lacrimal caruncle Excretory duct

Lacrimal sac

Orbital ridge

, -: ,, ,, ,, ' \" .�'�>\..) : : \ "

Lacrimal punctum

Inferior canaliculus

I

Nasolacrimal duct

-

I

\ \

'�

''''-

Fig. 20- 1 29 Nasolacrimal drainage system.

348

VARIABLE PROJECTIONS

Examination procedure

Contrast medium

Preliminary Caldwell, Waters, and lateral radiographs are usually taken for evalua­ tion of the paranasal sinuses. The fol low­ i ng steps are observed: • To expedite i maging after the introduc­ tion of the contrast medium, perform the injection procedure with the patient seated before a vertical grid device. • If preferred, place the patient in the supine position for the introduction of the medium and then turn the patient to the prone position for i maging. • After anesthetizing the conj unctiva and puncta, dilate the punctum of the canaliculus to be i njected (the upper punctum when the lower is blocked); then insert the round-tipped lacrimal needle i nto the canaliculus. The pa­ tency of the canals is tested by irrigat­ ing them with normal sali ne solution. I f the canals are found t o b e patent, the examination may be terminated.

Because oil is immiscible with the watery tear secretion, an oil-based, iodinated con­ trast medium is employed in examinations of the nasolacrimal duct system. Either a compound with low v i scosity or an ethiodized oil may be used after the medium has been warmed to body tem­ perature to further reduce its viscosity. Injection supplies

The items required for the injection are as follows: Sterile cotton balls, gauze sponges, and cotton-tipped applicators Sterile sponge forceps Sterile pack containing punctum dila­ tors, l acri mal needles, and 2-ml Luer-Lok syringes Local anesthetic solution Sterile normal sal i ne solution Contrast medium Waste basin

Fig. 20- 1 30 Right lateral nasolacrimal drainage system, showing complete blockage between dilated lacrimal sac and naso­ lacrimal duct (arrow).

• Immediately after the contrast medium

•

•

•

•

•

has been introduced and the needle with­ drawn, take the Caldwell or Waters and lateral projections in rapid succession. Repeat the same images at specified in­ tervals to fol low the progress of the contrast medium through the channels. Usually, make follow-up radiographs at a postinjection interval of 7 to 10 min­ utes and again at a 1 5- to 20-minute in­ terval, at which time the medium will have passed through patent ducts and will be seen on the floor of the nasal cavity and on the pharyngeal mucosa. After the initial i maging of the first side, inject the contralateral side if needed. When this is done, rotate the head slightly ( 1 0 to 1 5 degrees) away from the fil m to separate the bi l aterally opacified ducts in the lateral projection. For contrast studies of the nasolacrimal duct system (Figs. 20- 1 30 and 20- 1 3 1 ), use the same exposure factors as for routine paranasal sinus studies.

Fig. 20- 1 31 Right lateral nasolacrimal drainage system, demon­ strating nasolacrimal ducts and patent communication with contrast in nasal cavity on left side (arrowhead). Because the patient's head is rotated slightly, the right nasolacrimal duct (arrow) is not superimposed on the left duct.

349

21

OUTLINE

Panetoacanthial facial bones. Waters method

SUMMARY OF PROJ ECTIONS

P R OJ ECTIO NS, POSITIONS, & M ET H O DS

360

Facial bones

Parletoacanthlal

WATERS

362

Facial bones

Modified

MODIFIED WATERS

364

Facial bones

REVERSE WATERS CALDWELL

PA axlal

366 368

bones

370

Nasal bones

372

arches

374

arch

376

arch

378

arches

Lateral

R and L

Submentovertical MAY MODIFIED TOWNE

AP axlal

380

Mandibular

AP axial

382

Mandibular rami

PA

383

Mandibular rami

PA axlal

384

Mandibular

PA

385

Mandibular

PA axlal

386

Mandible

Axlolateral

389

Mandible

Submentovertical

390

Mandible

Verticosubmental

392

articulations

AP axial

394

articulations

Axlolateral

R and L

articulations

Axlolateral

R and L

396 398

Mandible

Panoramic

TOMOGRAPHY

Icons in the Essential column indicate projections frequently performed in the United States and Canada. Students should be competent in these projections.

SUMMARY OF PATHOLOGY Please refer to Chapter 20 for a summary of pathology for this chapter.

EXPOSURE TECH N I QUE CHART ESSENTIAL PROJ ECTIONS FAC I A L

Part

em

kVp'

Facial Bones* Lateral

15

70

Waters Method

24

Reverse Waters Caldwell Method

AEC

SID

200s

·0·

48"

8

x

1 0 in

1 30

80

200s

.�

48"

8

x

1 0 in

251

24

80

200s

.�

48"

8

x

1 0 in

251

20

75

200s

.�

48"

8

x

1 0 in

240

2

50

200s

3

48"

8

x

l O in

8

Zygomatic Arches* SMV Tangential AP Axial

23 20 17

65 65 70

0.03 0.03 0.08

200s 200s 200s

6 6 16

48" 48" 48"

8 8 8

x x x

1 0 in 1 0 in 1 0 in

43 53 1 58

Mandibular Rami* PA PA Axial

17 17

75 75

0.06 0.06

200s 200s

12 12

48" 48"

8 8

x x

1 0 in 1 0 in

1 09 1 09

Mandible* Axiolateral Oblique

13

75

0.025

200s

5

48"

8

x

1 0 in

40

TMJ* AP Axial Axiolateral Oblique

21 15

80 75

0.08 0.07

200s 200s

16 14

48" 48"

8 8

x x

1 0 in 1 0 in

21 1 1 20

Nasal Bones* Lateral

tm

BONES

mA

mAs

IR

Doset (mrad)

s,

Small focal spot. 'kVp values are for a 3-phase 1 2-pulse generator. 'Relative doses for comparison use. All doses are skin entrance for average adult at cm indicated. 'Bucky, 1 6: 1 Grid. Screen/Film Speed 300.

353

��.

RAD I OGRAPHY

-,,,. .. ...

Radiation Protection Protection of the patient from unnecessary radiation is a professional responsibil ity of the radiographer (see Chapter I for spe­ cific guidelines). In this chapter, with a few exceptions because of central ray an­ gulations, radiation shielding of the pa­ tient is not specified or illustrated because the professional community and the fed­ eral government have reported that a lead shield over the patient's pelvis does not sign ificantly reduce gonadal exposure during radiography of the facial bones. Nonetheless, shielding the abdomen of a pregnant woman is recommended by the authors of this atlas. I nfants and chi ldren, however, should be protected from radiation by shielding the thyroid and thymus glands and the gonads. The protective lead shielding used to cover the thyroid and thymus glands can also as­ sist in immobilizing the pediatric patient. The most effective way to protect pa­ tients from unnecessary radiation is to re­ strict the radiation beam by using proper col l i mation. Taking care to ensure that the patient is properly instructed and immobi­ l ized also reduces the chance of having to repeat the procedure and thereby exposing the patient to more radiation.

Facial Bone Projections Removed-Ninth Edition Advances in computed tomography (CT) have virtually eliminated many projec­ tions of the facial bones. As a result, dis­ cussions of a number of facial bones have been eliminated from this chapter. These projections may be reviewed in their en­ tirety in the eighth and other previous edi­ tions of this atlas. The fol lowing I I pro­ jections are not covered in this edition: Facial bones • Parietoorbital oblique projection • PA axial oblique projection: Law method Zygomatic arch • PA axial oblique projection: modified

Fuchs method Maxillae • Superoi nferior projection (intraoral) • AP axial projection ( intraoral ) • AP axial oblique projection (intraoral) Mandible • I nferosuperior projection ( intraoral) Mandibular symphysis • AP axial projection ( intraoral) Temporomandibular articulations • Axiolateral oblique projection • Axiolateral projection: Albers-Schonberg

method • Axiolateral projection: Zanelli method

Facial Bone Projections Removed-Tenth Edition Zygomatic arches • PA axial: Modified Tittetington

354

Facial Bones

'"

LATERAL PROJECTION R or L position Image receptor: 8 x 1 0 inch (1 8 X

24 cm) lengthwise Position of patient • Place the patient in a semi prone or

obl iquely eated po ition before a verti­ cal grid device. Position of part • Adjust the patient's head so that the

midsagittal plane is parallel with the I R and the interpupillary l ine is perpendic­ ular to the I R . Adj ust the flexion o f the patient's neck so that the infraorbitomeatal l i ne ( IOML) is parallel with the transverse axis of the J R ( Figs. 2 1 - 1 to 2 1 -3). • I mmobi lize the head. • Respiration: Suspend. •

Fig. 2 1 - 1 Lateral facial bones.

C,R,

C.R.

Rr-=-++-Ir-'---I--, -----< C,R. t-t---t---.rt------< C.R,

Fig. 2 1 -2 Upright radiography.

Fig. 2 1 -3 Table radiography.

355

Facial Bones

Central ray

Perpendicular and entering the lateral surface of the zygomatic bone halfway between the outer canthus and the ex­ ternal auditory meatus (EAM). • Center the T R to the central ray.

•

Structures shown

Thi s projection demonstrates a lateral im­ age of the bones of the face, with the right and left sides superimposed (Fig. 2 1 -4).

356

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • All facial bones in their entirety, with the zygomatic bone i n the center • Almost perfectly superimposed mandibu­ lar rami • Superimposed orbital roofs • No rotation of sel la turcica

Facial Bones

Frontal sinus Nasal bone Sella turcica

Maxillary sinus External acoustic meatus Maxilla

Mandible

Fig. 2 1 -4 Lateral facial bones.

357

Facial Profile

LATERAL PROJECTION

Position of patient

Central ray

R or L position

• Place the patient in a semi prone position

• Perpendicular to the lateral surface of

or seated before a vertical grid device.

the zygomatic bone and halfway be­ tween the outer canthus and the EAM. • Center the IR to the central ray.

Relationship of bony and soft tissue contours

One film is placed in the IR in the usual manner, and a second film is placed in a light-tight, nonscreened film holder and placed on top of the I R ; the two fi l ms are exposed simultaneously with the tech­ nique factors called for in lateral facial bone projection.

Position of part • Rest the patient's head in a lateral posi­

tion with the midsagittal plane paral lel and the i nterpupillary l i ne perpendicu­ lar to the plane of the IR. • Adjust the flexion of the patient's neck so that the IOML is paral lel with the transverse axis of the IR. I mmobilize the head. • Respiration: Suspend. •

Image receptor: 8 x 1 0 i nch ( 1 8 x 24 cm) lengthwise

Fig. 2 1 -5 Lateral facial profile: normal bony demonstration.

358

Structures shown

The intensifying screen i mage shows a bone-negative lateral image of the bony structures of the face (Fig. 2 1 -5 ) . The fil m packet placed on top of the I R (soft tissue-negative i mage, Fig. 2 1 -6), l acks the high-contrast effect of the i ntensify­ i ng screens, and therefore shows the soft tissue structures. The bone-negative im­ age of Fig. 2 1 -5 can be contact-printed in the darkroom to obtain a tone-reversed image (bone-positive i mage, Fig. 2 1 -7 ) . This bone-positive image c a n b e super­ imposed on the soft tissue-negative pro­ jection (see Fig. 2 1 -6) to demonstrate the relationship between the bony and the soft ti ssue structures (Fig. 2 1 - 8 ) .

Fig. 2 1 -6 Lateral facial profile: nonscreen exposure for soft tissue.

Facial Profile

EVALUATION CRITERIA

The following should be clearly demon­ strated : • Soft tissue of face • No rotation of face • Relation between bony and soft tissue structures visible if bone-positive and soft tissue-negative images are superimposed

Fig. 2 1 -7 Lateral facial profile: bone-positive reversal image.

Fig. 2 1 -8 Lateral facial profile: superimposed bone, positive reversal image.

359

Facial Bones

..

PARIETOACANTH IAl PROJECTION WATERS M ETHODl Image receptor: 8 x 1 0 i nch ( 1 8 X 24 cm) lengthwise

Rest the patient's head on the tip of the extended chin. Hyperextend the neck so that the orbitomeatal l i ne (OML) forms a 37-degree angle with the plane of the IR. Note that the mentomeatal l ine will be approxi mately perpendicular to the plane of the I R ; the average patient's nose will be about � inch ( 1 .9 cm) away from the grid device. Adjust the head so that the midsagittal plane is perpendicular to the plane of the IR (Figs. 2 1 -9 to 2 1 - 1 1 ). Center the I R at the level of the acan­ truon. I mmobi lize the head. • Respiration: Suspend.

•

Position of patient •

•

Place the patient in the prone or seated­ upright position. Center the midsagittal plane of the pa­ tient's body to the midline of the grid device.

IWaters CA: Modification of the occipito-frontal po­ sition in roentgenography of the accessory nasal si­ nuses, A rch Radiol Electrotherapy 20: I S , 1 9 1 S.

Central ray

Position of part •

•

•

•

Perpendicular to exit the acantruon

Structures shown

The Waters method demonstrates the or­ bits, maxil lae, and zygomatic arches ( Fig. 2 1 - 1 2) .

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Distance between the lateral border of the skull and the orbit equal on each side • Petrous ridges projected i mmediately below maJtiliary sinuses

•

Fig. 2 1 -9 Parietoacanthial facial bones: Waters method.

360

Facial Bones

C.R.

-+-

-

-<

-

C.R.

Mentomeatal line

Mentomeatal line

Fig. 2 1 - 1 0 Upright radiography.

Fig. 21 - 1 1 Table radiography.

Orbit

Zygomatic arch Maxillary sinus Maxilla Petrous ridge Mandibular angle

Fig. 2 1 - 1 2 Parietoacanthial facial bones. Waters method.

36 1

Facial Profile

MODIFIED PARIETOACANTH I AL PROJECTION

Fig. 2 1 - 1 3 Modified parietoacanthial facial bones: Waters method.

C.R.

C.R.

Fig. 2 1 - 1 4 Table radiography. modified parietoacanthiai facial bones: Waters method with OML adjusted to 55 degrees.

362

MODIFIED WATERS METHOD Although the parietoacanthial projection (Waters method) is widely used, many in­ stitutions modify the projection by radi­ ographing the patient using less extension of the patient's neck. This modification, al­ though sometimes called a "shal low" Waters, actually increases the angulation of the OML by placing it more perpendic­ ular to the plane of the IR. The patient's head is positioned as described using the Waters method, but the neck is extended a lesser amount. In the modification, the OML is adjusted to form an approxi mately 55-degree angle with the plane of the I R ( Figs. 2 1 - 1 3 t o 2 1 - 1 5 ) . The resulting radi­ ograph demonstrates the facial bones with less axial angulation than with the Waters method (see Fig. 2 1 - 1 2 ). With the modi­ fied Water method, the petrous ridges are projected immediately below the inferior border of the orbits at a level midway through the maxi llary sinuses ( Fig. 2 1 - 1 6) . The modified Waters method is a good projection to demonstrate blow-out frac­ tures. This places the orbital floor perpen­ dicular to the IR and paral lel to the CR demonstrating inferior displacement of the orbital floor and the commonly associ­ ated opacified maxil lary sinus.

Facial Profile

+--+-IC --� .R.

R----+---..,..Jf.---
Fig. 2 1 - 1 5 Upright radiography, modified parietoacanthial facial bones: Waters method with OML adjusted to 55 degrees.

Inferior orbital margin Maxillary sinus Zygomatic bone Petrous ridge

Nasal septum Mandible

Fig. 2 1 - 1 6 Modified parietoacanthial facial bones: Waters method.

363

Facial Profile

.. ACANTHIOPARIETAl PROJECTION

Position of part • Bringing the patient's chin up, adjust

REVERSE WATERS METHOD Image receptor: 24

x

30 cm

lengthwise The reverse Waters method is used to demonstrate the facial bones when the pa­ tient cannot be placed in the prone po ition.

• •

Position of patient • With the patient in the supine position,

center the mjdsagittal plane of the body to the midline of the grid.

• •

the extension of the neck so that the OML forms a 37-degree angle with the plane of the IR ( Fig. 2 1 - 1 7). If neces­ sary, place a support under the patient's shoulders to help extend the neck. Note that the MML is approximately perpendicular to the plane of the I R . Adjust the patient' s head s o that the midsagittal plane is perpendicular to the plane of the I R . I mmobi lize the head. Respiration: Suspend.

Central ray • Perpendicular to enter the acanthion

and centered to the J R .

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Distance between lateral border of the skull and orbit equal on each side • Petrous ridges projected below maxil­ lary sinuses

ACANTH IOPARI ETAl PROJECTION FOR TRAUMA Trauma patients are often unable to hy­ perextend the neck far enough to place the OML 37 degrees to the IR and the MML perpendicular to the plane of the IR. I n these patients, the acanthioparietal projec­ tion, or the reverse Waters projection can be achieved by adjusting the central ray so that it enters the acanthion while remain­ ing paral lel with the MML ( Fig 2 1 - 1 9).

Structures shown

The reverse Waters method demonstrates the superior facial bones. The i mage is similar to that obtained with the Waters method, but the facial structures are con­ siderably magnified (Fig. 2 1 - 1 8).

C.R.

�.,......,:--- Mentomeatal line

Fig. 2 1 - 1 7 Table radiography. Acanthioparietal facial bones: reverse Waters method with neck extended. Note that the MML is perpendicular to IR.

364

Facial Profile

Orbit

Zygomatic bone

Maxillary sinus Petrous ridge

Fig. 2 1 - 1 8 Acanthioparietal facial bones: reverse Waters method.

C.R.

I--,./-- Mentomeatal line

Fig. 2 1 - 1 9 Table radiography. Acanthioparietal facial bones: reverse Waters method with central ray parallel to mentomeatal line.

365

Facial Profile

PA AXIAL PROJECTION

Position of part

CALDWELL METHOD

•

Image receptor: 24 x 30 cm length­ WI

e

Position of patient •

•

•

•

Place the patient in either a prone or sealed position. Center the midsagittal plane of the pa­ tient's body to the midline of the glid. Rest the patient's forehead and nose on the table or against the upright B ucky. Flex the patient's elbows, place the arms in a comfortable position.

•

•

•

Adju t the flexion of the patient's neck so that the OML is perpendicular to the plane of the I R . If the patient is obese o r hypersthenic, a small radiolucent sponge may need to be placed in front of the forehead. Align the midsagittal plane perpendicu­ lar to the IR. This is accomplished by adjusting the lateral margins of the or­ bits or the EAMs equidistant from the tabletop. Immobil ize the patient's head, and cen­ ter the I R to the nasion (Figs. 2 1 -20). Respiration: Suspend.

Central ray •

•

•

Direct the centraJ ray to exit the na ion at an angle of 1 5 degrees caudad. For demonstration of the orbital ri ms, i n particular the orbital floors, u e a 30 degree caudal angle (sometimes re­ ferred to as the exaggerated Caldwell). Center the IR to the central ray.

Structures shown

The PA axial projection, Caldwell method demonstrates the orbital rims, maxillae, nasal septum, zygomatic bones, and the anterior nasal spine. When the central ray is angled 1 5 degrees caudad to the nasion, the petrous ridges are projected into the lower third of the orbits (Fig. 2 1 -2 1 ). When the central ray is angled 30 degrees caudad the petrous ridges are projected below the inferior margins of the orbits.

Fig. 2 1 -20 Upright radiography, PA axial facial bones Caldwell method.

366

Facial Profile

EVALUATION CRITERIA

The fol lowi ng should be clearly demon­ strated: • Entire cranial perimeter showing three disti nct tables of squamous bone • Equal distance from lateral border of skull to lateral border of orbit on both sides • Symmetric petrous ri dges l y i ng i n lower third o f orbit • Penetration of frontal bone without ex­ cessive density at lateral borders of skull which will then demonstrate the facial bones

Frontal sinus

Crista galli Superior orbital margin

Superior orbital fissure Ethmoidal sinus

Petrous ridge Inferior orbital margin

Fig. 2 1 -21 PA axial facial bones, Caldwell method,

367

Nasal Bones

.. LATERAL PROJECTION R and L positions Image receptor: 8 x 10 i nch ( 1 8 x

24 cm) crosswise for two exposures on one IR or a 2Yz X 3 inch (57 X 76 mm) occlusal film for each Position of patient • With the patient in a semi prone posi­

tion, adj ust the rotation of the body so that the midsagittal plane of the head can be placed horizontally.

Position of part

Placement of film

• Adjust the head so that the midsagittal

• When using occlusal fil m for the exam­

plane is paral lel with the tabletop, and the interpupi llary line is perpendicular to the tabletop. • Adj ust the flexion of the patient's neck so that the IOML is parallel with the transverse axis of the IR (Figs. 2 1 -22 and 2 1 -23). • Support the mandible to prevent rotation. • Respiration: S uspend.

ination, tape the side marker onto the outer lower corner of the pebbled side of the film packet. • Place a sandbag under the side of the nose, against the orbit and cheek, to support the fi l m packet. • Adjust the film packet so that the pebbled surface faces and is parallel with the mid­ sagittal plane and so that its upper border projects apprOldmately Yz inch ( 1 .3 cm) above the supraorbital ridge. • Press the fi l m packet firmly against the maxi l l a and supraorbital ridge (Fig. 2 1 -24).

Placement of IR • When using an 8 X 10 inch ( 1 8 X

24 cm) I R, sl ide the unmasked half of the lR under the frontonasal region and center it to the nasion (see Fig. 2 1 -22). This centering allows space for the identification marker to be projected across the upper part of the IR. Tape the side marker ( R or L) in position.

Bridge of the nose, flat or concave • Place the fil m packet at an angle under

the supraorbital ridge. • Turn the corner of the packet back

enough to ease the sharp edge so that it can be placed without discomfort to the patient. • Place the rounded corner just medial to the inner canthus, and press the upper border firmly against the inferior sur­ face of the supraorbital ridge. • I nstruct the patient to hold the film packet in position so that its plane is parallel with the midsagittal plane of the head.

Fig. 2 1 -22 Lateral nasal bones.

C.R.

C.R.

-

Fig. 21 -23 Table radiography. 368

Fig. 21 -24 Lateral nasal bones using occlusal film.

Nasal Bones

EVALUATION CRITERIA

Central ray

Structures shown

• Perpendicular to the bridge of the nose

The lateral i mages of the nasal bones demonstrate the side nearer the fil m or f R and the soft structures o f the nose (Figs. 2 1 -25 and 2 1 -26). Both sides are exam­ i ned for comparison.

at a point Y; inch ( 1 .3 cm) distal to the nasion . • Use close collimation.

Nasofrontal suture

A

The following should be clearly demon­ strated: • No rotation of nasal bone and soft tissue • Anterior nasal spine and frontonasal suture

------

Nasal bone -------';

B

Anterior nasal spine of maxilla -------'

Fig. 2 1 -25 Nasal bones. A, Right lateral. B, Left lateral.

Fig. 21 -26 Lateral nasal bones using occlusal film. 369

Nasal Bones

TANGENTIAL PROJECTION The success of this projection depends on the followi ng: ( I ) adjusting and having the patient hold the occlusal film packet be­ tween the teeth or using the larger IR placed under the chin so that the plane of the fi lm is perpendicular to the glabel­ loalveolar line and ( 2 ) directing the central ray along the glabelloalveolar li ne perpen­ dicular to the plane of the IR.

Position of part

Intraoral film • Tape a side marker (R or L) onto one

Extraoral lR • Elevate the side of the I R adjacent to

•

•

Image receptor: 8 x 1 0 inch ( 1 8 x 24 cm) IR placed crosswise under the chin or 2 � X 3 inch (57 X 76 mm) oc­

•

clusal fi lm held between the anterior teeth. The use of occlu al film is rec­ ommended because of the reduced object-to-i mage receptor distance.

• •

the patient on a small sandbag or a folded towel. Rest the patient's head on the fully ex­ tended chin, and center the IR to the midsagittal plane j ust anterior to the chin. Adj ust the incl ination of the IR so that its plane is perpendicular to the glabel­ loalveolar line. Adjust the patient's head so that the midsagittal plane is perpendicular to the plane of the IR (Fig. 2 1 -27). Immobil ize the head. Respiration: Suspend.

• •

• •

•

Position of patient • Place the patient in either a recumbent

•

side of the pebbled surface of the film packet. With the patient supine, rest the head on the table or elevate it on a sponge. With the midsagittal plane of the head vertical, adjust the head so that the glabelloalveolar line is horizontal . I mmobi lize the head. With its long axis directed anteroposte­ riorly and the pebbled surface facing upward, i nsert the film packet approxi­ mately I i nch (2.5 cm) i nto the mouth. Center the packet to the mid agittal plane, and then instruct the patient to close the lips and teeth so that the fi lm is held in position with its plane per­ pendicular to the glabelloalveolar li ne (Figs. 2 1 -28 and 2 1 -29 ). Respiration: S uspend.

or seated position. • Seat the patient so that the chin can be sUPPolted on a sandbag or an inclined IR.

Fig. 2 1 -27 Tangential nasal bones.

370

Fig. 21 -28 Tangential nasal bones.

Nasal Bones

EVALUATION CRITERIA

Central ray •

Parallel to glabel loalveolar line and perpendicular to the plane of the i mage receptor

Structures shown

A tangential projection of only a portion of the nasal bones that extend beyond the glabelloalveolar line is shown (Fig. 2 1 -30). Thi projection is used primarily to demon­ strate medial or lateral displacement of fragments in fractures.

The fol lowing should be clearly demon­ strated: • Nasal bone with minimal superimposi­ tion unless the patient has a prominent forehead, recessed nose, or protruding upper teeth • No rotation of the nose • Soft tissue NOTE: Because the nasal bones do not have sufficient body to cast a shadow through the dense superjacent and subjacent structures, the tangential projection cannot be used success­ ful l y in chi ldren or in adults who have very short nasal bones, a concave face, or protrud­ ing upper teeth.

Fig. 2 1 -29 Table radiography.

Septal cartilage

Nasal bone

Fig. 2 1 -30 Tangential nasal bones.

37 1

Zygomatic Arches

..

SUBME NTOVERTICAL PROJECTION

This projection is similar to the submen­ tovertical (SMV) projection described in Chapter 20. Image receptor: 8 x 1 0 inch ( 1 8 X

24 cm) crosswise Position of patient • Place the patient in a seated-upright or

Fig. 21 -31 Submentovertical zygomatic arches.

supine position. A vertical head unit greatly assists the patient who is unable to hyperextend the neck. • When the supine position is used, ele­ vate the patient's trunk on several firm pil lows or a suitable pad to allow com­ plete extension of the neck. Flex the pa­ tient's knees to relax the abdominal muscles. • Center the midsagittal plane of the pa­ tient's body to the midline of the grid device. Position of part • Hyperextend the patient's neck com­

pletely so that the IOML is as nearly par­ allel with the plane of the [R as possible. • Rest the patient's head on its vertex, and adjust the head 0 that the mid­ sagittal plane is perpendicular to the plane of the I R (Figs. 2 1 -3 1 to 2 1 -33). • Respiration: S uspend. C.R. Fig. 2 1 -32 Upright radiography.

Fig. 2 1 -33 Table radiography.

372

Zygomatic Arches

Central ray •

•

Structures shown

Perpendicular to the IOML and enter­ i ng the midsagittal plane of the throat at a level approximately I i nch (2.5 cm) posterior to the outer canthi . Center the I R to the central ray.

Bilateral symmetric SMV i mages of the zygomatic arches are shown, projected free of superimposed structures (Fig. 2 1 -34). Unless very flat or traumatically depressed, the arches, being farther from the IR, are projected beyond the prominent parietal eminences by the divergent x-ray beam.

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Zygomatic arches free from overlying structures • Zygomatic arches symmetric and with­ out foreshortening • No rotation of head NOTE: The zygomatic arches are wel l demon­ strated with a decrease in the exposure factors used for this projection of the cranial base.

A

Temporal process of zygomatic bone

B

Zygomatic arch

Fig. 2 1 -34 A, Submentovertical projection demonstrating normal zygomatic arch (right) and depressed fracture (arrow) of left zygomatic arch caused by patient being struck during a fisffight. B, Tangential zygomatic arches. 373

Zygomatic Arch

.. TANGENTIAL PROJECTION Image receptor: 8 x 10 inch ( 1 8 x

24 cm) Position of patient o

Seat the patient with the back against a vertical grid device, or place the patient in the supine position with the trunk elevated on everal firm pil lows and the knees flexed to permit complete exten­ sion of the neck.

Position of part Seated position o

o

Fig. 2 1 -35 Tangential zygomatic arch. o

o

i head 1 5° top of tilt .. ---< C.R. I---====--....-c::.-

C.R.

Fig. 2 1 -36 Upright radiography.

C.R.

1 5° top of C.R. head tilt --

Fig. 2 1 -37 Table radiography.

374

o

Hyperextend the patient's neck, and rest the head on its vertex . Adjust the position o f the patient's head so that the [OML is as parallel as possi­ ble with the plane of the I R . Rotate the midsagittal plane o f the head approxi mately 1 5 degrees toward the side being examined. Tilt the top of the head approxi mately 1 5 degrees away from the side being examined. This rotation and tilt ensure that the central ray is tangent to the lat­ eral surface of the skul l . The central ray thus skims across the lateral portion of the mandibular angle and the parietal bone to project the zygomatic arch onto the I R . Center the zygomatic arch t o the I R (Figs. 2 1 -35 and 2 1 -36).

Zygomatic Arch

Central ray

Supine position o o

•

o

o

o

o

Rest the patient's head on i ts vertex. Elevate the upper end of the [R on sand­ bags, or place it on an angle sponge of suitable size. Adjust the elevation of the IR and the extension of the patient's neck 0 that the IOML is placed as nearly parallel with the plane of the IR as possible. Rotate and tilt the midsagittal plane of the head approximately 1 5 degrees to­ ward the side bei ng examined (simi lar to the upright position) . If the IOML is parallel with the plane of the IR, center the IR to the zygo­ matic arch; if not, displace the IR so that the midpoint of the IR coincides with the central ray (Fig. 2 1 -37). Attach a strip of adhesive tape to the in­ ferior surface of the chin; draw the tape upward, and anchor it to the edge of the table or IR stand. This usually affords sufficient support. Do not put adhesive surface directly on the patient's kin. Respiration: Suspend.

o

o

Perpendicular to the IOML and cen­ tered to the zygomatic arch at a point approxi mately I inch (2.5 cm) posterior to the outer canthus. Centered to the I R

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Zygomatic arch free from overlying structures • Zygomatic arch not overexposed

Structures shown

A tangential image of one zygomatic arch is seen free of superimposition (Fig. 2 1 -38). Thi projection is particularly useful in pa­ tients with depressed fractures or flat cheek­ bones.

_______

Temporal process of zygomatic bone

�------ Zygomatic arch Temporal bone

Fig. 2 1 -38 Tangential zygomatic arch.

375

Zygomatic Arch

TANGENTIAL PROJECTION MAY M ETHOD Image receptor: 8 x 10 inch ( 1 8 X 24 cm) cros wise for two exposures Position of patient • Place the patient in the prone position,

or seat the patient before a vertical grid device. Position of part • Completely extend the patient's neck so

that the IOML is as parallel with the plane of the IR as possible. Rest the pa­ tient's chin on the grid device. • Rotate the midsagittal plane approxi­ mately 1 5 degrees away from the side being examined; then tilt the top of the head away from the side being exam­ ined approxi mately 1 5 degrees. This ro­ tation and tilt ensure that the central ray is tangent to the lateral surface of the skull. The central ray thus skims across the lateral portion of the parietal bone and the mandibular angle to project the zygomatic arch onto the IR (Figs. 2 1 -39 to 2 1 -4 1 ). • Respiration: S uspend.

Fig. 2 1 -39 Tangential zygomatic arch: May method.

C.R.

\

Fig. 2 1 -40 Upright radiography.

1 5° top of head tilt ---

C.R.

1 5°

Fig. 2 1 -41 Table radiography.

376

C.R.

1 5° top of head tilt

Zygomatic Arch

EVALUATION CRITERIA

Central ray • Perpendicular to the IOML and through

the zygomatic arch at a point approxi­ mately I Yz inches (3.8 cm) posterior to the outer canthus. • Center the IR to the central ray.

The fol lowing should be clearly demon­ strated: • Zygomatic arch in its entirety and free from overlying structures

Structures shown

The May method demonstrates the zygo­ matic arch free of superimposition (Fig. 2 1 -42). This projection is particularly use­ ful with patients who have depressed frac­ tures or flat cheekbones.

Temporal process of zygomatic bone

Zygomatic arch

Temporal bone

Fig. 2 1 -42 Tangential zygomatic arch: May method.

377

Zygomatic Arches

.. AP AXIAL PROJECTION MODIFIED TOWN E M ETHOD Image receptor: 8 x 10 i nch ( 1 8 X 24 cm) crosswi e Position of patient • Place the patient in the seated-upright •

or supine position. Center the midsagittal plane of the body to the midline of the grid.

Position of part •

•

•

Adjust the patient's head so that the midsagittal plane is perpendicular to the midl ine of the grid. Adjust the flexion of the neck so that the OML is perpendicular to the plane of the IR ( Figs. 2 1 -43 to 2 1 -45 ) . Respiralion: S uspend.

Central ray

Directed to enter the glabella approxi­ mately I inch (2.5 cm) above the nasion at an angle of 30 degrees caudad. • If the patient is unable to sufficiently flex the neck, adjust the IOML perpen­ dicular with the IR and direct the cen­ tral ray 37 degrees caudad. • Center the IR to the central ray.

•

EVALUATION CRITERIA

The following should be clearly demon­ strated: • No overlap of zygomatic arches by mandible • No rotation evident because arches are symmetric • Zygomatic arches projected lateral to mandibular rami

Structures shown

A symmetric AP axial projection of both zygomatic arches is demon trated. The arches should be projected free of super­ i mposition (Fig. 2 1 -46).

-,-_-7-C.R.

Fig. 2 1 -43 AP axial zygomatic arches, modified Towne method.

Fig, 2 1 -44 Upright radiography, modified Towne method .

C.R,

Fig. 2 1 -45 Table radiography, modified Towne method.

378

Zygomatic Arches

Occipital bone Mandible Zygomatic arch

Mandible

Fig. 2 1 -46 AP axial zygomatic arches, modified Towne method.

379

Mandibular Symphysis

AP AXIAL PROJECTION Image receptor: 2� x 3 inch (57 X 76 mm) occlusal film or 8 X 1 0 inch ( 1 8 X 24 cm) IR crosswise. Position of patient

Seat the patient at one end of the radio­ graphic table. • Elevate the fil m packet or IR on a suit­ able support so that the patient can ex­ tend the neck and maintain the chin in a horizontal plane in order to place it in close contact with the fi lm holder. • Tape a ide marker ( R or L) onto one corner of the occlusal film, and place the fi lm in position with its pebbled ur­ face up and its long axis directed an­ teroposteriorly. •

Fig. 2 1 -47 AP axial mandibular symphysis.

Upright position • With the midsagittal plane of the pa­

C.R.

tient's head perpendicular and centered to the midline of the film, adjust the fully extended chin wel l forward on the film to allow for the angulation of the central ray. The support under the chin is usu­ ally sufficient to maintain the head in po­ sition (Figs. 2 1 -47 and 2 1 -48). • Shield gonads. • Respiration: Suspend. Central ray • Direct posteriorly at an angle of 40 to 45 degrees and center it to the mandibu­

lar ymphysis ( m idway between the lips and the tip of the chin) for the up­ right patient.

Fig. 21 -48 Upright radiography.

Supine position •

C.R.

•

• •

•

•

•

Fig. 2 1 -49 Table radiography.

380

Rest the patient's head on its occiput, with the midsagittal plane vertical. Adjust the flexion of the patient's neck so that the inferior border of the body of the mandible is vertical ( Fig. 2 1 -49) . I mmobi lize the head. Adjust the fil m packet in position, with its pebbled surface in contact with the chin and its long axis in line with the midsagittal plane. Tape the packet to the skin, or have the patient hold the packet in po ition if possible. Direct the central ray to the mandibular symphysis at an angle of 40 or 45 de­ grees caudad in the supine patient. Respiration: Suspend.

Mandibular Symphysis

EVALUATION CRITERIA

Structures shown

The AP axial projection shows the mandibular symphysis, mental foramina, and roots of the lower incisors and canines (Fig. 2 1 -50).

The fol lowing should be clearly demon­ strated: • Mandibular symphysis and adj acent mentum • Roots of the lower anterior teeth • No rotation of the mandible

Mandibular symphysis

Mental foramen Teeth roots �iiI;::=�==---""::::'.v-

Fig. 2 1 -50 AP axial mandibular symphysis.

38 1

Mandibular Rami

.. PA PROJECTION Image receptor: 8 x 10 i nch ( 1 8 x

24 cm) crosswise Position ot patient

Place the patient in the prone position, or seat the patient before a vertical grid device.

•

EVALUATION CRITERIA

Structures shown

The PA projection shows the mandibular body and rami (Figs. 2 1 -52 and 2 1 -53). The central part of the body is not well shown because of the superi mposed spine. This radiographic approach i s usually em­ ployed to demonstrate medial or lateral displacement of fragments in fractures of the rami.

The fol lowi ng should be clearly demon­ trated: • Mandibular body and rami symmetric on each side • Entire mandible

Position ot part •

•

• •

Rest the patient's forehead and nose on the I R . Adjust the OML to be perpen­ dicular to the plane of the I R . Adjust the head s o that its midsagittal plane is perpendicu lar to the plane of the l R ( Fig. 2 1 -5 1 ). Immobil ize the head. Respiration: Suspend.

Central ray • •

Perpendicular to exit the acanthion. Center the JR to the central ray.

Fig. 2 1 -51 PA mandibular rami.

Condyle

Mastoid process Fracture

Body

Fig. 2 1 -52 PA mandibular rami showing fracture of right superior ramus,

382

Fig. 2 1 -53 Fracture of left mandibular ramus (arrow) incurred when the patient's chin struck the steering wheel during an auto accident,

Mandibular Rami

.. PA AXIAL PROJECTION Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm) crosswise Position of patient

Position of part

Structures shown

• Rest the patient's forehead and nose on

The PA axial projection shows the mandi­ bular body and rami (Fig. 2 1 -55). The central part of the body is not well shown because of the superimposed spine. This radiographic approach is usually em­ ployed to demonstrate medial or lateral displacement of fragments in fractures of the rami.

• •

• Place the patient i n the prone position,

or seat the patient before a vertical grid device.

• •

the I R holder. Adjust the OML to be perpendicular to the plane of the I R . Adj ust the patient's head so that the midsagittal plane is perpendicular to the plane of the I R (Fig. 2 1 -54). Immobilize the patient's head. Respiration: Suspend.

EVALUATION CRITERIA

Central ray • Directed 20 or 25 degrees cephalad to

exit at the acanthion. • Center the IR to the central ray.

Fig. 21 -54 PA axial mandibular rami.

The fol lowing should be clearly demon­ strated: • Mandibular body and rami symmetric on each side • Condylar processes • Entire mandible

Fig. 2 1 -55 PA axial mandibular body rami.

383

Mandibular Body

PA PROJ ECTION

o

Image receptor: 8 x 1 0 inch (1 8 X

EVALUATION CRITERIA

Central ray o

Perpendicular to the level of the l ips. Center the IR to the central ray.

24 em) lengthwise Structures shown Position of patient o

Place the patient in the prone position, or seat the patient before a vertical grid device.

The following should be clearly demon­ strated: • Mandibular body symmetric on each side

This i mage demonstrates the mandibular body (Fig. 2 1 -57).

Position of part o

o

o

With the midsagittal plane of the pa­ tient's head centered to the midline of the I R, rest the head on the nose and chin so that the anterior surface of the mandibular symphysis is parallel with the plane of the JR. This position places the acanthiomeatal line (AML) nearly perpendicular to the IR plane. Adjust the patient's head so that the midsagittal plane is perpendicular to the plane of the IR ( Fig. 2 1 -56). Respiration: Suspend.

Fig. 21 -56 PA mandibular body.

Ramus Symphysis Body Angle

Fig. 2 1 -57 PA mandibular body. 384

Mandibular Body

PA AXIAL PROJECTION Image receptor: 8 x 10 inch ( 1 8 X

24 cm) lengthwise Position of patient • Place the patient in the prone position,

or seat the patient before a vertical grid device. Position of part • With the midsagittal plane of the pa­

tient's head centered to the midline of the l R, rest the head on the nose and chin so that the anterior surface of the mandibular symphysis is parallel with the plane of the IR. This position places the AML nearly perpendicular to the plane of the I R . • Adju t the patient's head s o that the midsagittal plane is perpendicular to the plane of the IR (Fig. 2 1 -5 8 ) . • Respiration: Suspend.

Central ray

Structures shown

• Directed midway between the temporo­

This i mage shows the mandibular body and TMJs (Fig. 2 1 -59).

mandibular joints (TMJs) at an angle of 30 degrees cephalad. Zanell i ' recom­ mended that better contrast around the TMJs could be obtained if the patient was i nstructed to fill the mouth with air for this projection. • Center the IR to the central ray.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • TMJs just inferior to the mastoid process • Symmetric rami

'Zanelli A: Le proiezioni radiografiche del l ' artico­ lazione temporomandibolare, Radiol Med 1 6:495, 1 929.

Fig. 2 1 -58 PA axial mandibular body.

Mastoid process Condyle Coronoid process

Ramus

Body Symphysis

Fig. 2 1 -59 PA axial mandibular body. 385

Mandible

'"

AXIOLATERAL OBLIQUE PROJECTION

The goal of this projection is to place the desired portion of the mandible parallel with the I R . Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm) I R placed according to region Position of patient

Place the patient in the seated, semi­ prone, or semisupine position. Position of part • Place the patient's head in a lateral po­ Fig. 2 1 -60 Axiolateral oblique for mandibular ramus.

sition with the interpupillary l i ne per­ pendicular to the I R . The mouth should be closed with teeth together. • Extend the patient's neck enough that the long axis of the mandibular body is parallel with the transverse axis of the IR. Thi s prevents superimposition of the cervical spine. • If the projection i s to be performed on the tabletop, position the IR so that the complete body of the mandible is on the I R . • Adju t the rotation o f the patient's head to place the area of interest paral lel to the IR as fol lows: Ramus • Keep the patient's head in a true lateral

position (Fig. 2 1 -60). Body • Rotate the patient's head 30 degrees to­

ward the IR (Fig. 2 1 -6 1 ). Symphysis Fig. 2 1 -61 Axiolateral oblique for mandibular body.

• Rotate the patient's head 45 degrees to­

ward the IR ( Fig. 2 1 -62). NOTE: When the patient i in the semisupine position, place the I R on a wedge device or wedge sponge (Fig. 2 1 -63). Central ray • Directed 25 degrees cephalad to pass

directly through the mandibular region of interest. (See note on p. 388.) • Center the I R to the central ray for pro­ jection done on upright grid units. Structures shown

Each axiolateral obl ique projection demonstrates the region of the mandible that was parallel with the IR (Figs. 2 1 -64 to 2 1 -66).

Fig. 2 1 -62 Axiolateral oblique for mandibular symphysis. 386

Mandible

Fig. 2 1 -63 Semisupine axiolateral oblique mandibular body and symphysis.

Coronoid process

Ramus Body Hyoid bone

Angle

Fig. 2 1 -64 Axiolateral oblique mandibular body.

387

Mandible

EVALUATION CRITERIA

•

The following should be clearly demon­ strated: Ramus and body • •

Symphysis •

No overlap of the ramus by the opposite side of the mandible No elongation or foreshortening of ra­ mu or body

No superimposition of the ramus by the cervical spine

•

No overlap of the mentum region by the opposite side of the mandible No foreshorteni ng of the mentum region

NOTE: To reduce the possibility of projecting the shoulder over the mandible when radi­ ographing muscular or hypersthenic patients, adjust the mid agittal plane of the patient's skull with an approximate I S-degree angle, open inferiorly. The cephalad angulation of 1 0 degree of the central ray maintains the optimal 2S-degree central ray/part angle relationship.

Temporomandibular joint Condyle Coronoid process

Ramus Body

Angle

Fig. 2 1 -65 Axiolateral oblique mandibular ramus.

Symphysis Body

Fig. 2 1 -66 Axiolateral oblique mandibular symphysis. 388

Mandible

SUBMENTOVE RTICAl PROJECTION

Position of part

Structures shown

• With the neck fully extended, rest the

The SMV projection of the mandibular body shows the coronoid and condyloid processes of the rami (Fig. 2 1 -68) .

Image receptor: 8 x 1 0 inch ( 1 8 X

24 cm) lengthwise • Position of patient • Place the patient upright in front of a

vertical grid device or in the upi ne po­ sition. When the patient is supine, ele­ vate the shoulders on firm pillows to permit complete extension of the neck. • Flex the patient's knees to relax the ab­ dominal muscles and thus relieve strain on the neck muscles. • Center the midsagittal plane of the body to the midline of the grid device.

•

• •

head on its vertex and adjust the head so that the midsagittal plane is vertical. Adj ust the IOML as parallel as possible with the plane of the IR (Fig. 2 1 -67). When the neck cannot be extended enough so that the IOML is parallel with the IR plane, angle the grid device and place it parallel to the IOML. I mmobi lize the head. Respiration: Suspend.

Central ray • Perpendicular to the IOML and cen­

tered midway between the angles of the mandible.

EVALUATION CRITERIA The fol lowing should be clearly demon­ strated: • Distance between the lateral border of the skull and the mandible equal on both sides • Condyles of the mandible anterior to the pars petrosae • Symphysis extending almost to the an­ terior border of the face so that the mandible is not foreshortened

Fig. 2 1 -67 Submentovertical mandible.

Symphysis Body Coronoid process Ramus Condyle Petrous ridge

Fig. 2 1 -68 Submentovertical mandible.

389

Mandible

VERTICOSUBMENTAl PROJECTION Image receptor: 8 x 10 inch ( 1 8 x

24 cm) Position of patient • Examine the patient in the prone po i­

tion, or seat the patient so that the chin can be positioned across the I R .

EVALUATION CRITERIA

Structures shown

The VSM projection demonstrates the mandible as seen from above the patient. The coronoid processes are easily visible on either image ( Figs. 2 1 -70 and 2 1 -7 1 ), but the condyle and neck of the condylar processes are better shown with the greater angle ( i .e., with the central ray at right angle to the occlusal plane) .

The fol lowing should be clearly demon­ strated: • Distance between the lateral border of the sku ll and the mandible equal on both sides • Angles of the mandible anterior to the petrosae

Position of part • Place the I R on a small sandbag and ad­

• • • • • • •

just it, either horizontal ly or at a cranial inclination, so that it is in close contact with the patient's throat. Center the midsagittal plane of the pa­ tient's head to the midline of the I R . Fully extend the patient's neck, and rest the chin on the I R . Adjust the patient's head 0 that the midsagittal plane is vertical. Adjust the IOML to be parallel with the I R ( Fig. 2 1 -69). I mmobilize the head. ShieLd gonads. Respiration: Suspend.

NOTE: For this projection, be sure to provide gonadal shielding for the patient. A sheet of leaded rubber should be placed across the pa­ tient's lap, and close col limation should be maintained. Central ray • Directed through the midsagittal plane

and entering at the level just posterior to the outer canthi, perpendicular to ei­ ther the IOML (see Fig. 2 1 -69 ) or the occlusal plane.

390

Fig. 2 1 -69 Verticosubmental mandible.

Mandible

Body

Ramus

Condyle -----.,,!';-�=

Fig. 2 1 -70 Verticosubmental mandible with central roy perpendicular to IOML.

Coronoid process Angle Condyle Petrous ridge Mastoid air cells

Fig. 2 1 -7 1 Verticosubmental mandible with central roy perpendicular to occlusal plane.

39 1

Temporomandibular Articulations

.. AP AXIAL PROJECTION

Fig. 21 -72 AP axial TMJs.

For radiography of the TMJs in the closed-mouth position, the posterior teeth, rather than the incisors, must be in contact. Occlusion of the incisors places the mandible in a position of protrusion, and the condyles are carried out of the mandibular fossae. In the open-mouth po­ sition, the mouth should be opened as wide as possible but not with the mandible protruded Gutted forward). Because of the danger of fragment dis­ placeme nt, the open-mouth position should not be attempted in patients with recent injury. Trauma patients are exam­ ined without any stress movement of the mandible. Tomography is particularly useful when a fracture or dislocation suspected. Image receptor: 8 x 1 0 inch ( 1 8 x

24 cm) lengthwise _r--_-+C. R.

Position of patient o

Place the patient in a supine or seated­ upright position with the posterior skull in contact with the upright B ucky.

Position of part o

o

o

Fig. 2 1 -73 Upright radiography.

Fig. 2 1 -74 Table radiography.

392

Adj ust the patient's head so that the midsagittal plane is perpendicular to the plane of the I R . Flex the patient's neck s o that the OML is perpendicular to the plane of the I R (Figs. 2 1 -72 to 2 1 -74). Respiration: Suspend.

Temporomandibular Articulations

Central ray • Directed 35 degrees caudad, centered

midway between the TMJs, and enter­ i ng at a point approximately 3 inches (7.6 cm) above the nasion. • Expose one i mage with the mouth closed; when not contraindicated, ex­ pose one with the mouth open. • Center the I R to the central ray. Condyle

Structures shown

The AP axial projection demonstrates the condyles of the mandible and the mandibular fossae of the temporal bones ( Figs. 2 1 -75 and 2 1 -76).

Ramus

EVALUATION CRITERIA Fig. 2 1 -75 AP axial TMJs: mouth closed.

The fol lowing should be clearly demon­ strated: • No rotation of head • Minimal superimposition of petrosa on the condyle in the closed-mouth exam­ ination • Condyle and temporomandibular artic­ ulation below pars petrosa in the open­ mouth position

Condyle

Ramus

Fig. 2 1 -76 AP axial TMJs: mouth open.

393

Temporomandibular Articulations

AXIOLATERAL PROJECTION R and l positions Image receptor: 8 x 10 inch ( 1 8 X

24 cm) crosswise Position of patient o

o

Put a mark on each cheek at a point Y2 inch ( 1 .3 cm) antelior to the EAM and I inch (2.5 cm) inferior to the EAM to localize the TMJ if needed. Place the patient in a semiprone posi­ tion, or seat the patient before a vertical grid device.

Position of part o

Fig. 2 1 -77 Axiolateral TMJ : mouth closed. o

o o o

�--+-�'------ C.R.

o

Fig. 2 1 -78 Upright radiography.

C.R. C.R.

Fig. 2 1 -79 Table radiography.

394

Center a point Y2 inch ( 1 . 3 cm) anterior to the EAM to the I R, and place the pa­ tient's head in the lateral position with the affected side closest to the IR. Adj ust the patient's head so that the midsagittal plane is parallel with the plane of the I R and the interpupi llary l ine is perpendicular to the IR plane (Figs. 2 1 -77 to 2 1 -79). Immobilize the head. Respiration: Suspend. After making the exposure with the pa­ tient's mouth closed, change the IR; then, unless contraindicated, have the patient open the mouth wide (Fig. 2 1 -80). Recheck the patient's position and make the second exposure.

Temporomandibular Articulations

Central ray • Directed to the midpoint of the TR at an

angle of 25 or 30 degrees caudad. The central ray enters about � inch ( 1 .3 cm) anterior and 2 inches (5 cm) superior to the upside EAM. Structures shown

These images show the TMJ when the mouth is open and closed (Figs. 2 1 -8 1 and 2 1 -82). Examine both sides for comparison. EVALUATION CRITERIA

The following should be clearly demon­ strated: • Temporomandibular articulation lying anterior to the EAM • Condyle lying in mandibular fossa in the closed-mouth examination • Condyle lying inferior to articular tu­ bercle in the open-mouth examination if the patient is normal and able to open the mouth wide

Fig. 2 1 -80 Axiolateral TMJ with mouth open.

External [-"------ acoustic meatus

Fig. 2 1 -81 Axiolateral TMJ, mouth closed. Mandibular condyle (small dots) mandibular fossa (large dots) are demonstrated. Mandibular condyle of side away from film also seen (arrow).

Fig. 2 1 -82 Axiolateral TMJ, mouth open. Mandibular fossa (arrow) and mandibular condyle (arrowheads) are demonstrated.

395

Temporomandibular Articulations

.. AXIOLATE RAL OBLIQUE PROJECTION R and L positions Image receptor: 8 x 1 0 inch ( 1 8 x

24 cm) crosswise Position of patient • Place the patient in a semi prone posi­

Fig. 2 1 -83 Axiolateral oblique TMJ.

tion, or seat the patient before a vertical grid device. • In TMJ examinations, make one expo­ sure with the mouth closed and, when not contraindicated, one exposure with the mouth open. • Use an I R-changing tunnel or B ucky tray so that the patient's head does not have to be adjusted between the two exposures. • Examine both sides for comparison. Position of part • Center a point 1'2 inch ( 1 .3 cm) anterior

• -.,..-C -=-<.. .R.

• t---,/---+..::..- -I----(C.R.

Fig. 21 -84 Upright radiography.

•

• • •

•

to the EAM to the J R, and rest the pa­ tient's cheek on the grid device. Rotate the midsagittal plane of the head approximately 1 5 degrees toward the I R . Adj ust the interpupillary line perpen­ dicular to the plane of the f R . Adjust the flexion o f the patient's neck so that the AML is parallel with the transverse axis of the IR (Figs. 2 1 -83 to 2 1 -85). Immobi l ize the head. Respiration: Suspend. After making the exposure with the mouth closed, change the IR and instruct the patient to open the mouth wide. Recheck the position of the AML, and make the second exposure.

C.R.

Central ray • Directed 1 5 degrees caudad and exiting C.R.

1 5°

Fig. 2 1 -85 Table radiography.

396

through the TMJ closest to the IR. The central ray enters about 1 1'2 inches (3.8 cm) superior to the upside EAM.

Temporomandibular Articulations

Structures shown

The i mages in the open-mouth and c1osed­ mouth positions demonstrate the condyles and necks of the mandible. The images also show the relation between the mandibular fossa and the condyle. The open-mouth po­ sition demonstrates the mandibular fossa and the inferior and anterior excursion of the condyle. Both sides are examined for comparison (Fig. 2 1 -86). The closed-mouth position demonstrates fractures of the neck and condyle of the ramus. EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Temporomandibular articulation • Condyle lying in mandibular fossa in the closed-mouth examination • Condyle lying inferior to articular tu­ bercle in the open-mouth projection i f the patient is normal and able t o open the mouth wide

Mandibular fossa

A..�"--1ii---;-=- 1 Articular tubercle External acoustic meatus

A

Condyle

B

Fig. 2 1 -86 Axiolateral oblique TMJ. A, Mouth open, right side. B, Mouth open, left side (same patient) showing more movement on the left side.

397

Panoramic Tomogra phy of the Mandible Panoramic tomography, pan tomography, and rotational tomography are terms used to designate the technique employed to produce tomograms of curved sUlfaces. This technique of body-section radiogra­ phy provides a panoramic image of the entire mandible, including the TMJ, and of both dental arches on one long, narrow fi lm curved to conform to the shape of the patient's jaw. Only the structures near the axis of rotation are sharply defined.

Two types of equipment are available for pantomography. I n the first type the patient and film are rotated before a stationary x-ray tube. This type of machine consists of ( I ) a specially designed chair mounted on a turntable and (2) a second turntable to support a 4 X 1 0 inch ( 1 0.2 X 25.4 cm) film enclosed in a flexible IR. The seated and immobilized patient and the film are electronically rotated in opposite directions at coordinated speeds. The x-ray tube re­ mains stationary. I n one machine the expo­ sure is interrupted in the midline.

In the second type of unit the x-ray tube and the IR rotate in the same direction around the seated and immobilized patient (Fig. 2 1 -87). The x-ray tube and lR drum are attached to an overhead carriage that is supported by the vertical stand assembly. The chair of this unit is fixed to the base but can be removed to accommodate wheelchair patients. The attached head holder and radiolucent bite device center and immobi l ize the patient's head. A scale on the head holder indicates the jaw size. The film, 5 X 1 2 inches ( 1 2.7 X 30.5 cm) or 5 X 14 inches ( 1 2 .7 X 35.6 cm) as in­ dicated, is placed in a flexible IR that at­ taches firmly to the film drum.

Fig. 2 1 -87 Panograph radiographic unit. (Courtesy Gendex.)

398

I n both types of equipment the beam of radiation is sharply coll imated at the tube aperture by a lead diaphragm with a nar­ row vertical slit. A corresponding slit di­ aphragm is fixed between the patient and the I R so that the patient and the I R (or the tube and the fi l m ) rotate. Each narrow area of the part is recorded on the film without overlap and without fogging from scattered and secondary radiation. The rotation time varies from 1 0 to 20 seconds in different makes of equipment. This requires a long exposure time. Because of the slit diaphragm, however, radiation exposure to the patient at each fraction of a second is restricted to the skin surface that is passing before the nar­ row vertical slit aperture.

Panoramic tomography provides a dis­ tortion-free lateral i mage of the entire mandible (Fig. 2 1 -88). It also affords the most comfortable way to position patients who have sustained severe mandibular or TMJ trauma, both before and after splint wiring of the teeth. It must, of course, be supplemented with an AP, PA, or a verti­ cosubmental projection to establish frag­ ment position.

This tomographic technique is useful for general survey studies of various den­ tal abnormalities. It is also used to supple­ ment rather than replace conventional periapical radiographs. NOTE: A more comprehensive discussion of basic tomographic principles is presented in Chapter 29.

Condyle ��-- Maxillary sinus

r="7---:=F=-----:==::!=� Central incisor Dental fillings

Angle Mandibular symphysis

Fig. 2 1 -88 Panoramic tomogram.

399

OUTLINE

SUM MARY OF PROJ ECTIONS

PROJ ECTIO NS, POSITIONS, & METHODS

CALDWELL 41 4

Maxi

sinuses

Parletoacanthial

416

Maxillary and ethmoidal sinuses

Parietoacanthial

418

Ethmoidal and sphenoidal sinuses

Submentovertlcal

420

Ethmoidal, sphenoidal, and maxillary sinuses

PA

WATERS Open mouth

WATERS

Icons in the Essential column indicate projections frequently performed in the United States and Canada. Students should be competent in these projections.

ANATOMY

.

Sinuses The air-containing cavities situated in the frontal, ethmoidal, and sphenoidal bones of the cranium and the maxillary bones of the face are called the paran.asal sinuses be­ cause of their formation from the nasal mu­ cosa and their continued communication with the nasal fossas ( Figs. 22- 1 and 22-2). Although the functions of the sinuses are not agreed on by all anatomists, these cav­ ities are believed to do the following: Serve as a resonating chamber for the voice • Decrease the weight of the skull by containing air Help to warm and moisten inhaled air • Act as shock absorbers in trauma (as air bag do i n automobiles) Possibly control the immune system •

•

•

.

:�

Maxillary Sinuses

The sinuses begin to develop early in fe­ tal life, at first appearing as small saccula­ tions of the mucosa of the nasal meatus and recesses. As the pouches, or sacs, grow, they gradual ly i nvade the respective bones to form the air sinuses and cells. The maxillary sinuses are usually sufficiently well developed and aerated at birth to be demonstrated radiographically. The other groups of sinuses develop more slowly, so that by age 6 or 7 years the frontal and sphenoidal sinuses are distinguishable from the ethmoidal air cells, which they resemble in both size and position. The ethmoidal air cells develop during puberty, and the sinuses are not completely devel­ oped until the seventeenth or eighteenth year of l ife. When fully developed, each of the sinuses communicates with the others and with the nasal cavity. An understanding of the actual size, shape, and position of the sinuses within the skull is made possible by studying the sinuses on computed tomography (CT) head i mages (Fig. 22-2).

The largest sinuses, the maxillary sinuses, are paired and are located in the body of each maxilla (see Figs. 22- 1 and 22-2). Although the maxillary sinuses appear rec­ tangular in the lateral image, they are ap­ proximately pyramidal in shape and have only three wal ls. The apice are directed i nferiorly and laterally. The two maxillary si nuses vary considerably in size and hape but are usually symmetric. In adults, each maxillary sinus is approximately 3.5 cm high and 2.5 to 3 cm wide. The sinus is often divided into subcompartments by partial septa, and occasionally it is divided into two sinuses by a complete septum. The sinus floor presents several elevation that correspond to the roots of the subja­ cent teeth. The maxillary sinuses commu­ nicate with the middle nasal meatus at the superior aspect of the sinus.

Ethmoidal air cells � __ __ � A �____�

(

J

Frontal sinuses

B A Sphenoidal sinuses -MI:'lXllllarv sinus

Fig. 22- 1 A, Anterior aspect of paranasal sinuses. showing lateral relationship to each other and to surrounding parts. B, Schematic drawing of paranasal sinuses. showing AP relationship to each other and surrounding parts.

403

B

A

D

c

Fig. 22-2 A, Coronal CT image of the frontal sinuses. B, Coronal CT scan of the maxillary sinuses. C, Axial CT image of the maxil­ lary sinuses. D, Axial CT image of the sphenoid sinuses. E, Sagittal CT Image of the sphenoidal sinus. Continued

404

E

F

G

Fig. 22-2, cont'd F, Coronal CT image of the ethmoid sinuses. G, Axial CT image of the ethmoidal sinuses. From Kelley L Peterson eM:

Sectional anatomy,

St Louis. 1 977. Mosby.

405

Frontal Sinuses

Ethmoidal Sinuses

Sphenoidal Sinuses

The fronfal sinuses, the second largest si­ nuses, are paired and are normally located between the tables of the vertical plate of the frontal bone (see Figs. 22- 1 and 22-2). The frontal sinuses vary greatly i n size and form. Occasionally they are absent. One or both may be as l arge as approximately 2 to 2.5 cm in the vertical or lateral dimension. The si nuses often extend beyond the frontal region of the bone, most frequently into the orbital plates. The intersinus sep­ fum is usually deviated from the midline; for this reason the frontal sinuses are rarely symmetric. Multiple septa are sometimes present. Like maxillary sinuses, the frontal sinuses drain into the middle nasal meatus.

The two ethmoidal sinuses are located within the lateral masses of the labyrinths of the ethmoid bone. They are composed of a varying number of air cells that are divided into three main groups: anteriOl; middle, and posterior (see Figs. 22- 1 and 22-2). The anterior and middle ethmoidal cell s vary in number from two to eight, and each group opens i nto the middle nasal meatus. The posterior cell s vary in number from two to six or more and drain into the superior nasal meatus.

The sphenoidal sinuses are normally paired and occupy the body of the sphenoid bone (see Figs. 22- 1 and 22-2). Anatomists state that only one sphenoidal si nus is often present; however, more than two sphe­ noidal sinuses are never present. The sphe­ noidal sinuses vary considerably in size and shape and are usually asymmetric. They lie immediately below the sel la tur­ cica and extend between the dorsum sellas and the posterior ethmoidal air cel ls. The sphenoidal sinuses open into the phe­ noethmoidal recess of the nasal cavity.

SUM MARY OF PATHOLOGY

SUMMARY OF ANATOMY* Paranasal sinuses

Please refer to Chapter 20 for a summary of pathology for this chapter.

maxillary sinuses frontal sinuses intersinus septum ethmoidal sinuses anterior ethmoidal cells middle ethmoidal cells posterior ethmoidal cells sphenoidal sinuses 'See Addendum at the end of the volume for a summary of the changes in the anatomic terms used in the ninth edition.

EXPOSURE TECH N IQUE CHART ESSE NTIAL PROJ ECTIONS PA R A N A S A L S I N U S E S

Part

s,

em

kVp'

tm

mA

mAs

0.04

200s

8

Paranasal Sinuses (all): Lateral *

15

70

Frontal and Anterior Ethmoidal: PA axial (Caldwell) *

20

75

200s

Maxillary: Waters*

24

75

200s

Maxillary and Ethmoidal: Open-Mouth Waters*

24

75

Ethmoidal and Sphenoidal: SMV*

23

75

200s

Ethmoidal. Sphenoidal. Maxillary PN

20

75

200s

0. 1 4

200s

SID

IR

Doset (mrad)

48"

8

x

10 in

35

48"

8

x

1 0 in

285

48"

8

x

1 0 in

280

48"

8

x

1 0 in

230

0.0

48"

8

x

1 0 in

363

0.0

48 "

8

x

1 0 in

240

o� 0.0

28

Small focal spot. "kVp values are for a 3-phase 1 2-pulse generator. 'Relative doses for comparison use. All doses are skin entrance for average adult at em indicated. 'Bucky, 1 6: 1 Grid. Screen/Film Speed 300.

406

AEC

RADI OGRAPHY

Technical Considerations Radiographic density is probably more critical and more mi leading in the si­ nuses than in any other region of the body ( Figs. 22-3 to 22-5 ) . Overpenetration of the si n uses d i m i nishes or completely obliterates existing pathologic condition , and underpenetration can imulate patho­ logic conditions that do not exist.

.

Depending on the technique employed, the milliampere-second (mAs) and kilo­ volt (peak) ( kVp) factors should be bal­ anced so that both soft tissue structures and bony structures are demonstrated. Although good contrast is desirable, soft tissue areas may not be visualized with high contrast.

:']

Whenever possible, radiographs of the paranasal sinuses should be made with the patient in the upright position. Thi po i­ tion is best for demonstrating the presence or absence of fluid and differentiating be­ tween fluid and other pathologic condi­ tions. The value of the upright position in sinus examinations was pointed out by Crossl and Flecker. 2 The paranasal sinuses vary not only in size and form but also in position. The cells of one group frequently encroach on and resemble those of another group. This characteristic of the si nuses, together with their proximity to the vital intracranial organs, makes accurate radiographic demonstration of their anatomic structure of prime i mportance. The patient's head must be carefully placed in a sufficient number of positions so that the projec­ tions of each group of cavities are as free as possible of superimposed bony struc­ tures. The radiographs must be of such qual ity that it is possible to distinguish the cell of several groups of si nuses and their relationship to the urrounding structures. 'Cross KS: Radiography of the na al accessory si­ nuses, Med J Ails, 1 4:569, 1 927. 2Flecker H: Roentgenograms of the antrum, AJR 20:56, 1 928 ( letter).

Fig. 22-3 Correctly exposed radiograph of sinuses.

Fig. 22-4 Overexposed radiograph of sinuses demonstrating two artifacts caused by dirt on screens (arrows).

Fig. 22-5 Underexposed radiograph of sinuses.

407

Fig. 22-6 Coconut. vertical position: horizontal central ray. Air-fluid level is demonstrated (arrow).

Fig. 22-7 Coconut. vertical position: central ray angled 45 degrees upward . Note that air­ fluid level Is not as sharp.

408

Unless sinus radiographs are almost perfect technically, they are of l ittle diag­ nostic value. For this reason a precise technical procedure is necessary in radi­ ography of the paranasal si nuses. The first requirements are a small focal spot and clean imaging screens that have perfect contact. The radiographic contrast must similarly distinguish the sinuses from the surrounding structures. The head must be carefully positioned and rigidly immobi­ l ized, and respiration must be suspended for the exposures. The effect of both body position and central ray angulation is clearly demon­ strated in radiographs of a coconut held in position by head clamps. Fig. 22-6 shows a sharply defined air-fluid level. This co­ conut was placed in the vertical position, and the central ray was directed horizon­ tally. Fig. 22-7 was also taken with the co­ conut in the vertical position, but the cen­ tral ray was directed upward at an angle of 45 degrees to demonstrate the gradual fad­ ing of the fluid line when the central ray is not horizontal. This effect is much more pronounced in actual practice because of structural irregularities. Fig. 22-8 was made with the coconut in the horizontal position and the central ray directed verti­ cally. The resultant radiograph shows a homogeneous density throughout the cav­ ity of the coconut, with no evidence of an air-fluid level. Exudate contained in the sinuses is not fluid in the usual sense of the word but is commonly a heavy, semigelatinous mate­ rial. The exudate, rather than flowing freely, clings to the walls of the cavity and takes several mi nutes, depending on its viscosity, to shift position. For this rea on, when the position of a patient is changed or the patient's neck is flexed or extended to position the head for special projec­ tions, several minutes should be allowed for the exudate to gravitate to the desired location before the exposure is made.

Although numerous sinus projections are possible, with each serving a special purpose, many are used only when re­ quired to demonstrate a specific lesion. The consensus is that five standard projec­ tions adequately demonstrate all of the paranasal sinuses in the majority of pa­ tient . The following steps are observed in preparing for these projections: • Use a suitable protractor to check and adjust the position of the patient's head to ensure accurate positioning. • Have the patient remove dentures, hair­ pins, and ornaments such as earrings and necklaces before proceeding with the examination. • Because the patient' face is in contact with the I R holder or the IR itself for many of the radiographs, these items should be cleaned before the patient is positioned. Even with the most hygienic patients, the hair and face on patients are naturally oily and leave a residue. I f a patient i s sick, the residue is worse. During posi­ tioning of the patient's head, the hair, mouth, nose, and eyes come in direct con­ tact with the vertical grid device, tabletop, or I R . Medical asepsis can be promoted by placing a paper towel or sheet between the i maging surface and the patient. As standard procedure, the contacted area should be cleaned with a disi nfectant be­ fore and after positioning.

Radiation Protection Protection of the patient from unnecessary radiation is a professional responsibility of the radiographer. (See Chapter I for specific guideli nes.) [n this chapter, radia­ tion shielding of the patient is not speci­ fied or i l lustrated because the professional community and the federal government have reported that placing a lead shield over the patient's pelvis does not signifi­ cantly reduce gonadal exposure during radiography of the paranasal sinuses. However, shielding the abdomen of preg­ nant women is recommended. Infants and chi ldren, however, should be protected by radiation shielding of the thyroid and thymus glands and the go­ nads. The protective lead shielding used to cover the thyroid and thymus glands can also assist in immobil izing the pediatric patient. The most effective way to protect the patient from unnecessary radiation is to restrict the radi ation beam by using proper collimation. Taking care to ensure that the patient is properly i nstructed and immobil ized also reduces the chance of having to repeat the procedure, thereby further limiting the radiation exposure re­ ceived by the patient.

Sinus Projections Removed-Ninth Edition Advances in computed tomography have virtually elimi nated the need for many projections of the sinuses. The fol lowing four projections have been elimi nated from this chapter. These projections may be reviewed in their entirety in the eighth edition and other previous editions of this atlas. Sphenoidal sinuses • Verticosubmental projection: SchUller

method • PA axial projection (transoral ): Pirie

method Ethmoidal, frontal, and sphenoidal sinuses • Parietoorbital projection: Rhese method Relationship of teeth to floor of maxillary sinuses • PA axial oblique projection:

Law

method

Fig. 22-8 Coconut. horizontal position: vertical central ray. Note evidence of air-ftuid level.

409

Paranasal Sinuses

.. LATERAL PROJECTION R or L position Image receptor: 8 x 1 0 inch ( 1 8 x

24 C Ol )

EVALUATION CRITERIA

Central ray

Directed horizontal entering the pa­ tient's head Y2 to I inch ( 1 .3 to 2.5 Col) posterior to the outer canthus. • Center the IR to the CR. • I mmobil ize the head.

Position o f patient • Seat the patient before a vertical grid

device with the body placed in the RAO or LAO position so that the head can be adjusted in a true lateral position. Position of part • Rest the side of the patient's head on

the vertical grid device, and adjust the head in a true lateral position. The mid­ sagittal plane of the head is parallel with the plane of the I R, and the inter­ pupillary line is perpendicular to the plane of the J R . • The infraorbitomeatal line ( IOML) i s positioned horizontally t o ensure proper extension of the head. This posi­ tion places the IOML parallel with the transverse axis of the vertical grid de­ vice ( Fig. 22-9 ). • Respiration: Suspend.

Structures shown

A lateral projection shows the AP and su­ peroinferior dimensions of the paranasal sinuses, their relationship to surrounding structures, and the thickness of the outer table of the frontal bone (Fig. 22- 10). When the lateral projection is to be used for preoperative measurements, it should be made at a 72-inch ( l 83-cm) source-to-i mage receptor distance to min­ imize magnification and distortion.

The following should be clearly demon­ strated: • All four sinus groups, but the sphenoidal sinus is of primary importance • No rotation of sella turcica • Superimposed orbital roofs • Superimposed mandibular rami • Clearly visible si nuses • Close beam restriction of sinus area • Clearly visible air-fluid levels, if present NOTE: If the patient is unable to assume the up­ right body position, a lateral projection can be obtained using the dorsal decubitus position. The hOIizontal beam enables fluid levels to be seen. Positioning of the paI1 is the same, ex­ cept for the lOML, which is vertical rather than horizontal.

Fig. 22-9 Lateral sinuses.

410

Paranasal Sinuses

Frontal sinus

Sella turcica Sphenoidal sinus

Ethmoidal sinuses Maxillary sinus Superimposed mandibular rami

Fig. 22- 1 0 Lateral sinuses.

41 1

Frontal and Anterior Ethmoidal Sinuses

..

PA AXIAL PROJ ECTION

CALDWELL M ETHOD Because sinus images should always be obtained with the patient in the upright body position and a horizontal direction of the central ray, the Caldwell method is easily modified when using a head unit or other vertical grid device capable of angu­ l ar adj ustment is used. For the modifica­ tion, all anatomic landmarks and localiza­ tion planes remain unchanged.

Position of part Angled grid technique

Before positioning the patient, tilt the vertical grid device down so that an angle of 1 5 degrees is obtained (Fig. 22- 1 1 , A). Rest the patient's nose and forehead on the vertical grid device, and center the nasion to the I R . Adjust the midsagittal plane and orbito­ meatal l ine (OML) of the patient's head perpendicular to the plane of the IR. Note that this positioning places the OML perpendicular to the angled I R and 1 5 degrees from the horizontal cen­ tral ray (Fig. 22- 1 2, A). • I mmobilize the head. Respiration: Suspend.

•

•

•

•

Image receptor: 8 x 10 inch ( 1 8 x

24 cm) Position of patient • Seat the patient facing a vertical grid •

Vertical grid technique

When the vertical grid device cannot be angled, sl ightly extend the patient's neck, rest the tip of the nose on the grid device, and center the nasion to the I R . Position the patient's head s o the OML forms an angle of 1 5 degrees with the horizontal central ray. For support, place a radiolucent sponge between the fore­ head and the grid device (Figs. 22- 1 1 , B, and 22- 1 2, B). Adjust the midsagittal plane of the pa­ tient's head to be perpendicular to the plane of the IR. I mmobilize the head. • Respiration: S uspend.

•

•

•

•

•

device. Center the midsagittal plane of the pa­ tient's body to the midline of the grid.

A

,L-W�,..----.f-H---< C .R.

��"""----+'/f---
Fig. 22- 1 1 PA axial sinuses: Caldwell method. A, IR tilted 1 5 degrees. B. Same projection with vertical lR.

A

B

Fig. 22- 1 2 PA axial sinuses: Caldwell method. A. IR tilted 1 5 degrees. B, Same projection with vertical IR. 41 2

B

Frontal and Anterior Ethmoidal Sinuses

Central ray •

•

Directed horizontal to exit the nasion. Note that the I S-degree relationship be­ tween the central ray and the OML re­ mains the same for both techniques. Center the lR to the CR.

NOTE: The angLed grid technique is preferred because it brings the fR closer to the sinuses, thereby increasing resolution. Angulation of the grid device provides a natural position for placement of the patient's nose and forehead.

Structures shown

The angled grid technique and vertical grid technique demonstrate the frontal sinuses lying superior to the frontonasal suture; the anterior ethmoidal air cel ls lying on each side of the nasal fossas and immediately in­ ferior to the frontal sinuses; and the sphe­ noidal sinuses projected through the nasal fossas just inferior to or between the eth­ moidal air cells (Fig. 22- 1 3 ). The dense petrous pyramids extend from the inferior third of the orbit inferiorly to obscure the superior third of the maxillary sinus. This projection is used primarily for demonstra­ tion of the frontal sinuses and anterior eth­ moidal air cell .

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Equal distance between the lateral bor­ der of the skull and the lateral border of the orbits, indicating no rotation • Petrous ridge symmetric on both sides • Petrous ridge lying in the lower third of the orbit • Frontal si nuses lying above the fron­ tonasal suture and the anterior eth­ moidal air cel ls lying above the petrous ridges • Frontal and anterior ethmoidal air cel ls • Clearly visible air-fluid levels, if present • Close beam restriction of the sinus area

Frontal sinus

Ethmoidal sinus Petrous ridge

Sphenoidal sinus Maxillary sinus

Fig. 22- 1 3 PA axial sinuses.

41 3

Maxillary Sinuses

.. PARIETOACANTHIAL PROJECTION

•

WATERS METHOD •

Image receptor: 8 x 10 inch ( 1 8 X

24 cm)

Position of part

Position of patient

Place the patient seated in an upright position, facing the vertical grid device. Center the midsagittal plane of the pa­ tient's body to the midline of the grid device.

For the Waters method 1 .2 the goal i to hy­ perextend the patient's neck just enough to place the dense petrosae immediately below the maxil lary sinus floor (Fig. 221 4) . When the neck is extended too little, the petrosae are projected over the inferior portions of the maxillary si nuses and thus ob cure underlying pathologic conditions (Fig. 22- 1 5 ) . When the neck is extended too much, the maxillary sinuse are fore­ shortened and the antral floors are not demonstrated. ' Waters CA: A modification of the occipilofronlal posilion in the roenlgen examination of the acces­ sory nasal sinuses, Arch Radiol Ther 20: I S , 1 9 1 5 . 'Mahoney HO: Head and sinus positions, Xray Techn 1 :89. 1 930.

Because this position is relatively un­ comfortable for the patient to hold, have the I R and equipment in position so that the examination can be per­ formed quickly. • Hyperextend the patient's neck to ap­ proxi mately the correct position, and then center the IR to the acanthion. • Rest the patient's chin on the vertical grid device and adjust it so that the mid­ sagittal plane is perpendicular to the plane of the I R. • Using a protractor as a guide, adjust the head so that the OML forms an angle of 37 degrees from the plane of the I R (Figs. 22- 1 4 and 22- 1 6). As a position­ ing check for the average-shaped skull, the mentomeatal (MML) li ne should be approximately perpendicular to the I R plane. Immobil ize the head. Respiration: Suspend.

•

•

•

Fig. 22- 1 4 Proper positioning. Petrous ridges are projected below maxillary sinuses.

Fig. 22- 1 5 Improper positioning. Petrous ridges are superimposed on maxillary sinuses.

Fig. 22- 1 6 Parietoacanthial sinuses: Waters method.

414

Maxillary Sinuses

Central ray

Horizontal to the I R and exiting the acanthion Structures shown

The image shows a parietoacanthial pro­ jection of the maxillary sinu es, with the petrous ridges lying inferior to the floor of the sinuses (Fig. 22- 1 7) . The frontal and ethmoidal air cell are distorted.

The Waters method is also used to demonstrate the foramen rotundrum. The images of these structures are seen, one on each side, just inferior to the medial as­ pect of the orbital floor and superior to the roof of the maxillary sinuses.

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Petrous pyramjds lying immediately in­ ferior to the floor of the maxillary sinuses • Equal distance between the lateral bor­ der of the kull and the lateral border of the orbit on both sides, indicating no rotation • Orbits and maxillary sinuses symmetric on each ide • Maxillary sinuse • Close beam restriction of the sinus area • Clearly visible air-fluid levels, if present

Frontal sinus

Ethmoidal sinuses Infraorbital foramen Foramen rotund rum

A

Maxillary sinus m_---...:..:

Petrous ridge Mastoid air cells

B

Fig. 22- 1 7 A, Parietoacanthial sinuses: Waters method. B, Same pro­ jection. Note the clouded (lighter) appearance of the right maxillary sinus caused by fluid-filled sinus.

415

Maxillary and Ethmoidal Sinuses

.. PARIETOACANTHIAL PROJECTION OPE N-MOUTH WATERS M ETHOD Image receptor: 8 x 1 0 inch ( J 8 X

24 cm) This method provides an excel lent demonstration of the sphenoidal sinuses projected through the open mouth. For pa­ tients who cannot be placed in position for the submentovertical projection, the open.­ mouth Waters method and lateral projec­ tions may be the only techniques for demonstrating the sphenoidal sinuses. Because the open-mouth position is rela­ tively uncomfortable for the patient to hold, the radiographer must have the I R and equipment in position t o perform the examination quickly.

Position of part

Hyperextend the patient's neck to ap­ proximately the correct position, and then position the IR to the acanthion. Rest the patient's chin on the vertical grid device, and adju t it so that the midsagittal plane i perpendicular to the plane of the I R . Using a protractor a s a guide, adj ust the patient's head so that the OML forms an angle of 37 degrees from the plane of the I R . The MML will not be per­ pendicular (Fig. 22- 1 8 ) . Have the patient slowly open the mouth wide open. while holding the position. • Immobilize the head. Respiration: Suspend.

•

•

•

•

•

Fig. 22- 1 8 Parietoacanthial sinuses: open-mouth Waters method.

416

Maxillary and Ethmoidal Sinuses

EVALUATION CRITERIA

Central ray

Horizontal to the IR and exiting the acanthion Structures shown

The open-mouth Waters method demon­ strates the sphenoidal sinuses projected through the open mouth along with the maxi l lary sinuses (Fig. 22- 1 9).

The fol lowing should be clearly demon­ strated: • Petrous pyramid lying immediately in­ ferior to the floor of the maxiUary sinuses • Equal distance between the lateral bor­ der of the skull and the lateral border of the orbit on both sides, indicating no rotation • Orbits and maxillary sinuses symmetric on each side • Maxillary sinuses • Close beam restriction of the sinus area • Clearly visible air-fluid levels, if present • Sphenoidal sinuses projected through the open mouth

Maxillary sinus Upper teeth

Sphenoidal sinuses

Lower teeth

Fig. 22- 1 9 Open-mouth Waters modification demonstrates the sphenoidal sinuses pro­ jected through the open mouth along with the maxillary sinuses.

417

Ethmoidal a nd Sphenoidal Sinuses

.. SUBMENTOVERTICAl PROJECTION Image receptor: 8 x 10 inch ( 1 8 X

24 cm) Position of patient

The success of the submentovertical (SMV) projection depends on placing the I O M L a nearly parallel as pos ible with the plane of the I R and directing the cen­ tral ray perpendicular to the rOML. The upright position is recommended for all paranasal sinus radiographs and is also more comfortable for the patient. The following steps are observed: • Use a chair that supports the patient' back to obtain greater freedom in posi­ tioning the patient's body to place the IOML parallel with the I R . • Seat the patient far enough away from the vertical grid device 0 that the head can be fully extended (Figs. 22-20, A, and 22-2 1 ). If necessary to examine short-necked or hypersthenic patients, angle the vertical grid device downward to achieve a par­ allel relationship between the grid and the I O M L (Figs. 22-20, B, and 22-22). The di advantage of angl ing the verti­ cal grid device is that the central ray is not horizontal and air-fluid levels may not be demonstrated as easily as when the central ray is truly horizontal. •

Position of part Fig. 22-20 Submentovertical sinuses.

• Hyperextend the patient's neck as far as

•

•

1------1f:�-------«C .R. •

Fig. 22-21 Upright radiography, preferred position of skull.

Fig. 22-22 Upright radiography.

•

418

possible, and rest the head on its vertex. If the patient's mouth opens during hy­ perextension, ask the patient to keep the mouth closed to move the mandibular symphysi anteriorly. Adjust the patient's head so that the midsagittal plane is perpendicular to the midline of the I R . Adj ust the tube s o that the central ray is perpendicular to the I O M L ( ee Fig. 22-20). Immobi lize the patient's head. I n the absence of a head clamp, place a suit­ ably backed strip of adhesive tape across the tip of the chin and anchor it to the sides of the radiographic unit. Do not put adhesive surface directly on pa­ tient's skin. Respiration: Suspend.

Ethmoidal and Sphenoidal Sinuses

Central ray

Horizontal and perpendicular to the IOML through the sella turcica. The cen­ tral ray enters on the midsagittal plane approximately � inch ( 1 .9 cm) anterior to the level of the EAM.

EVALUATION CRITERIA

Structures shown

The SMV projection for the sinuses demonstrates a symmetric image of the anterior portion of the base of the skull . The sphenoidal sinus and ethmoidal air cells are shown ( Fig. 22-2 3 ) .

The following should be clearly demon­ strated: • Equal distance from the lateral border of the skull to the mandibular condyles on both sides indicating that the mid­ agittal plane is perpendicular (no tilt) • Anterior frontal bone superimposed by mental protuberance, indicating that the IOML is parallel (full extension) • Mandibular condyles anterior to petrous pyramids • Clearly visible air-fluid levels, if present

Maxillary sinus Ethmoidal sinuses Mandible

Vomer Sphenoidal sinus

Pharynx

Petrosa

Fig. 22-23 Submentovertical sinuses.

419

Ethmoidal, Sphenoidal, and Maxillary Sinuses

.. PA PROJECTIONS Although the patient's head is in the same position for the three projections, the structures shown depend on the direction and placement of the central ray. Image receptor: 8 x 1 0 inch ( 1 8 x

24 cm) Position of patient •

•

EVALUATION CRITERIA

Central ray •

Horizontal and perpendicular to the I R centered to exit a t the nasion

Structures shown

The posterior ethmoidal air cells are pro­ jected superior to the anterior air cells (Fig. 22-25 ).

The fol lowing should be clearly demon­ strated: • Posterior ethmoidal air cells just infe­ rior to cranial bones • Equal distance between the lateral bor­ der of the skull and the midsagittal plane on both sides, indicating no rotation • Petrous ridges symmetric on each side • Close beam restriction of sinus area

Place the patient in the seated-upright position. Center the midsagittal plane of the pa­ tient's body to the midline of the grid device.

Posterior ethmoidal sinuses Position of part • Center the nasion to the I R, rest the pa­

tient's forehead and nose on the grid device, and adjust the head so that the midsagittal plane is perpendicular to the plane of the IR. • Adjust the flexion of the patient's neck so that the OML is perpendicular to the plane of the IR (Fig. 22-24). • I mmobi lize the head. Respiration: Suspend. •

Fig. 22-24 PA posterior ethmoidal sinuses.

Sphenoid plane Petrous ridge Posterior ethmoid air ceJis inferior orbital margin

Fig. 22-25 PA posterior ethmoidal sinuses: perpendicular central ray.

420

Ethmoidal, Sphenoidal, and Maxillary Sinuses

Sphenoidal sinuses

Central ray

Position of part

• Directed at an angle of 1 0 degrees cepha­

• Center the glabel la to the J R , rest the

patient's forehead and nose on the grid device, and adjust the head so that the midsagittal plane is perpendicular to the IR. • Adjust the flexion of the neck so that the OML is perpendicular to the I R . • Immobi lize the head. • Respiration: S uspend.

lad, passing through the sphenoidal si­ nuses and exiting at the glabella. I f pos­ sible, tilt the head unit down so that an angle of 1 0 degrees is obtained, and di­ rect the central ray horizontally. Structures shown

The sphenoidal sinuses are projected through the frontal bone (Fig. 22-26 ) .

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Sphenoidal sinuses visible through the frontal bone just superior to frontal si­ nuses and ethmoidal air cells • Equal distance between the lateral bor­ der of the skull and the midsagittal plane on both sides, indicating no rotation • Petrous ridges symmetric on each side • Close beam restriction of sinus area

Petrous ridge Sphenoidal sinus

Nasal septum

Fig. 22-26 PA sphenoidal sinuses: central ray angulation of 1 0 degrees cephalad.

42 1

Ethmoidal , Sphenoidal, and Maxillary Sinuses

Maxillary sinuses

Central ray

Position of part

•

•

•

•

• •

Center the IR at a point midway be­ tween the infraorbital margins and the acanthion. Rest the patient's forehead and nose on the grid device, and adjust the head so that the midsagittal plane is perpendic­ ular to the IR. Adjust the flexion of the patient's neck so that the OML is perpendicular to the IR. Immobilize the head. Respiration : Suspend.

Horizontal and perpendicular to the I R, exiting midway between the infraor­ bital margins and the acanthion

Structures shown

The maxillary sinuses are projected infe­ rior to the base of the cranium (Fig. 22-27). The posterior ethmoidal air cells are well demonstrated in this projection.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated : • Maxil lary sinuses below the petrous ridges • Equal distance between the lateral bor­ der of the skull and the midsagittal plane on both sides, indicating no rotation • Petrous ridges symmetric on each side • Visible air-fluid levels in the maxillary sinus, if present • Close beam restriction of the sinus area

Petrous ridge Posterior ethmoidal air cells Maxillary sinus

Fig. 22-27 PA maxillary sinuses: perpendicular central ray.

422

23

OUTLINE

SUM MARY OF PROJ ECTI ONS

PROJECTIONS, POSITIONS & METHODS Page

Essential

Anatomy

Projection

Method

Position

Petromastoid portion

Axlolateral oblique

ORIGINAL LAW

4-

Petromastoid portion

Axlolateral oblique

MODIFIED LAW

Petromastoid portion

Axlolateral

HENSCHEN, SCH O LLER, LYSHOLM

438

4-

Petromastoid portion

STENVERS

440

4-

Axlolateral oblique (posterior profile)

Petromastoid portion

Axlolateral oblique (anterior profile)

ARCELIN

442

Petromastoid portion

Axlolateral oblique

MAYER

446

Petromastoid portion

AP axlal

TOWNE

448

Petromastoid portion

Submentovertlcal (SMV)

448

Petromastoid portion

Submentovertlcal (SMV)

HIRlZ MODIFICATION

430 432 434

452

Styloid processes

PA axlal

CAHOON

454

Jugular foramina

Submentovertlcal (SMV)

KEMP HARPER, ERASO MODIFICATION

456

Hypoglossal canal

Axlolateral oblique (anterior profile)

MILLER

Icons in the Essential column indicate projections frequently performed in the United States and Canada. Students should be competent in these projections.

SU M MARY OF PATHOLOGY Please refer to Chapter 20 for a summary of pathology for this chapter.

EXPOS U RE TEC H N IQUE CHART ESSE NTIAL PROJ ECTIONS T E M PORAL

BON E

Part

em

kVp·

tm

mA

mAs

Petromastoid Portion: Modiffed Lawt Stenvers* Arcelin*

15 16 15

75 75 75

0.07 0. 1 0 0. 1 0

200s 200s 200s

14 20 20

AEC

SID

IR

48" 48" 48"

8 x l 0 in. 8 x 10 in. 8 x 1 0 in.

Dose! (mrad)

1 17 1 67 1 67

s.

Small focal spot. ·kVp values are for a 3-phase 1 2-pulse generator. 'Relative doses for comparison use. All doses are skin entrance for average adult at cm indicated. 'Bucky. 1 6: 1 Grid. Screen/Film Speed 300.

425

. :::f"� � � .L� .�

RAD I OGRAPHY

Temporal Bone Anatomy A complete description of temporal bone anatomy is presented in Chapter 20.

Temporal Bone Projections Removed­ Ninth Edition Advances in computed tomography (CT) have virtually elimi nated the need for many projections of the temporal bone. Therefore a number of projections of the petromastoid portion have been elimi­ nated from this edition of the atlas. However, they are reviewed in the eighth edition and other previous editions. The eight deleted petromastoid portion projec­ tions are as follows:

Temporal Projections Removed-Tenth Edition Due to ongoing advances i n computed ra­ diography (CT), many projections of the temporal bone are no longer performed. The following projections have been re­ moved from this edition of the atlas. For reference to these projections, please see the ni nth edition and all previous editions of the atlas. AP tangential • H ickey method PA tangential (mastoid process) AP • Fuchs method AP oblique

Axiolateral oblique projection

• Wigby-Tayor method

• Part-angulation modified Law method Axiolateral oblique AP axial oblique projection

• Fuchs method

• Chausse 1 \ 1 method AP axial (transoral) AP axial oblique projection • Sansregret modification of Chausse I I I

method Axiolateral oblique projection • Low-Beer method Parietotemporal projection • Lysholm method PA axial projection • Hass method PA projection (transorbital) PA axial projection: Valdini method

426

• Chausse II method

Radiation Protection Protection of the patient from unnecessary radiation is a professional responsibil ity of the radiographer (see Chapters I and 2 for speci fic guidel ines). I n this chapter radia­ tion shielding of the patient is neither specified nor photographically shown be­ cause the professional community and the federal government have reported that placing a lead shield over the adult pa­ tient's pelvis does not significantly reduce gonadal exposure when obtaining radi­ ographs of the temporal bone. However, shielding the abdomen of pregnant women is recommended. Infants and children, however, should be protected by shieldi ng the thyroid and thymus glands and the gonads. The pro­ tective lead shielding used to cover the thyroid and thymus glands can also assist in immobi lizing the pediatric patient. The most effective way to protect the patient from unnecessary radiation is to restrict the radiation beam by using proper collimation. Taking care to ensure that the patient is properly instructed about the procedure and immobil ized also reduces the chance of having to repeat the proce­ dure, thereby further li miting the radiation exposure.

General Procedu res In an AP or lateral projection of the cra­ nium, the mastoid process is obscured by superi mpos ition of the dense petrous pyramids or the contralateral mastoid proce s. An unobstructed lateral projec­ tion of the mastoid process requires a slightly oblique orientation, which can be obtained by angl ing either the head or the central ray (Figs. 23- 1 to 23-3). The de­ grees of angulation that are recommended for this purpose by various authors cover a considerable range. The I S-degree double­ angle technique and the I S-degree and 2S­ degree single-angle techniques are most commonly used. Both mastoid processes are always exami ned for comparison purpo es. Therefore the radiographs must be exact dupl icates in both part position and tech­ nical quality. Likewise, radiographs made in follow-up examjnations mu t be exact duplicates of those made in preceding ex­ aminations. Every effort must be made to establ ish an exact procedure in centering and adjusting the part according to the speci fic localization points and planes used in the particular i mage. Errors in centering the part can be minirruzed by first adjusting the patient's head and then checkjng the posi60n with a protractor.

Fig. 23- 1 Midsagittal rotation of 1 5 degrees for mastoid process.

C.R.

Fig. 23-2 Midsagittal rotation of 15 degrees.

Mastoid air cells

External acoustic meatus

Temporomandibular Joint

Fig. 23-3 Mastoid process.

427

The auricles of the ears may be folded forward to keep the relatively dense mar­ gins cast by the ear cartilages from ob­ scuring the superimposed mastoid cells. Taping each auricle forward with a narrow strip of adhesive tape keeps them in place and at the same time mini mize discomfort to the patient by eliminating the necessity of repeated handling of a part that is often inflamed and tender. To prevent the adhe­ sive strip from overlapping the mastoid cells, it should be placed so that it does not extend beyond the posterior junction of the auricle and the head. Figs. 23-4 and 23-5 demonstrate how the auricle can ob­ scure the mastoid cells.

Fig. 23-4 Mastoid process: auricle folded forward (arrow).

428

Visualization of the sharp outlines of the thin, fragile walls of the mastoid cel ls requires the following: I . The effective focal spot of the x-ray tube must be no l arger than 0.6 mm. 2. High-resolution i maging systems must be u ed to demonstrate the small mas­ toid structures. 3. Perfect fi lm-screen contact and clean screen are essential. 4. The collimator must be adjusted to the smallest possible field size. Limiting the radiation area reduces the amount of sec­ ondary radiation that reaches the film. 5. During the exposure, complete head im­ mobilization and cessation of re pira­ tion are necessary. The slightest move­ ment, although not enough to cause visible blurring of the outlines of the comparatively gross surrounding struc­ tures, can diffuse the outlines of the thin cell wal ls. Unfortunately, when con­ fined to the cellular structure, the diffu­ sion cannot always be recognized as motion. For this reason the head must be rigidly immobilized.

Fig. 23-5 Mastoid process: auricle not folded forward (arrow).

429

Petromastoid Portion

AXIOLATERAL OBLIQUE PROJECTION

Position of patient

Position the patient with the head in a true lateral position. Adjust the flexion of the patient's head so that the interpupillary li ne is perpen­ dicular to the plane of the IR, and the infraorbitomeatal line ( IO M L ) and mid agittal plane are parallel with the IR plane ( Figs. 23-6 and 23-7). • Immobi lize the head. RespiraTion: Suspend.

•

ORIGINAL LAW METHOD Double-tube angulation

•

Image receptor: 8 x 1 0 inch ( 1 8 X

24 cm) Positioning to demonstrate the mastoid process in the axiolateral oblique projec­ tion was originally performed using a nongrid technique. The original position, as described by Law, used a double-tube angulation. Because grid techniques are commonly used today, the axiolateral oblique projection can also be modified. The modified projection does not require a sideways central ray angulation into the grid. I nstead it uses rotation of the mid­ sagittal plane and a caudal central ray. The radiographic images from both projec­ tions are almost identical in appearance.

•

C.R.

C.R.

A

....

"....( C.R.

-

-,.----:::< ::o- C.R.

B

Fig. 23-6 Axiolateral oblique petromastoid portion: original Laws method with nongrid. double­ tube angulation. A, Table radiography. B, Upright radiography.

430

Petromastoid Portion

EVALUATION CRITERIA

Central ray

Structures shown

• Directed at an angle of 1 5 degrees cau­

The axiolateral oblique projection demon­ strates the mastoid cells, the lateral por­ tion of the petrous pyramid, the superim­ posed i nternal acoustic meatus (lAM) and EAM, and, when present, the mastoid emissary vessel (Fig. 23-8).

dad and 1 5 degrees anteriorly. It enters approximately 2 inches (5 cm) po terior to, and 2 inches (5 cm) above, the upper­ most extemal acoustic meatus (EAM) and exits the downside mastoid process. • Center the IR to the central ray.

Fig. 23-7 Axiolateral oblique petromastoid portion: original Laws method, 15 degrees 1 5 degrees.

The following should be clearly demon­ strated: • Mastoid process closest to IR, with air cel ls centered to I R • Opposite mastoid process not superim­ posing but lying inferior and slightly anterior to mastoid of interest • Auricle of ear not superimposing the mastoid process • Superimposition of lAM and EAM • Temporomandibular joint (TMJ ) visi­ ble anterior to mastoid process • Close beam restriction to mastoid region

x

Auricle (taped forward) Mastoid antrum

Mastoid air cells Superimposed internal and external acoustic meatuses _--""jj Mandibular condyle Mastoid process

Fig. 23-8 Axiolateral oblique petromastoid portion: original Laws method.

43 1

Petromastoid Portion

..

AXIOLATERAL OBLIQUE PROJECTION MODIFIED LAW M ETHOD Single-tube angulation Image receptor: 8 x 10 inch ( 1 8 X

24 cm) Position of patient • Place the patient on the table in the

prone position, or seat the patient be­ fore a vertical grid device. • Tape each auricle forward with a nar­ row strip of adhesive tape.

-- -"1':r�j

Position of part • Position the patient's head in a lateral

Fig. 23-9 Axiolateral petromastoid portion: modified Law method with single-tube angulation.

•

•

• C.R.

C.R.

A

-r--�..(C.R.

B

H--",.-k--f-------< C.R.

Fig. 23- 1 0 A, Table radiography: single-tube angulation. B, Upright radiography.

432

• •

position with the affected side closest to the I R . Adjust the flexion o f the patient' head so that the IOML is parallel with the I R and the interpupi l lary line is perpendic­ ular to the I R . Rotate the patient's head toward the IR until the midsagittal plane is adj usted to an angle of 1 5 degrees ( Figs. 23-9 and 23- 1 0). Check the position of the head with a protractor. I mmobil ize the head. Respiration: Suspend.

Petromastoid Portion

Central ray

Structures shown

• Directed to the midpoint of the grid at

The axiolateral oblique projection demon­ strates the mastoid cells, the lateral por­ tion of the petrous pyramid, the superim­ posed lAM and EAM, and, when present, the mastoid emissary vessel (Fig. 23- 1 1 ).

an angle of 1 5 degrees caudad to exit the downside mastoid tip approxi­ mately I inch (2.5 cm) posterior to the EAM. The central ray enter approxi­ mately 2 inches (5 cm) posterior to, and 2 inches (5 cm) superior to, the upper­ most EAM . • Center the I R t o the central ray.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Mastoid process closest to IR, with air cel ls centered to I R • Opposite mastoid process not superim­ posing but lying inferior and slightly anterior to mastoid process of interest • Auricle of ear not superimposing mastoid process • Superimposition of lAM and EAM • TMJ visible anterior to mastoid process • Clo e beam restriction to mastoid region

Auricle (taped forward)

Internal and external acoustic meatuses Mastoid air celis

Mastoid process

Mandibular condyle

Fig. 23- 1 1 Axiolateral petromastoid portion: modified Law method.

433

Petromastoid Portion

AXIOLATERAL PROJECTION HENSCHEN, SCH U LLER, AND LYSHOLM METHODS Image receptor: 8 x 10 inch ( 1 8 X

24 cm) Position of patient • Place the patient in the prone po ition,

or preferably seat the patient before a vertical grid device. • When the mastoid cel ls are the point of interest, tape the auricles forward. Position of part • Place the patient's head in the true lat­

Fig. 23- 1 2 Axiolateral petromastoid portion: Henschen method, 15 degrees.

eral position with the midsagittal plane parallel with the plane of the IR and the interpupi llary line perpendicular to the TR plane. • Adj ust the flexion of the patient' neck so that the IOML is parallel with the transverse axis of the IR. • I mmobi lize the head. • Respiration: Suspend. Central ray • Directed to exit the EAM closest to the

,-

---,� C.R.

-

IR at the fol lowing caudal angles: Henschen method- 1 5 degrees caudad 1---t'��-+-"fi'I7""+"1- -----< C.R. (Figs. 23- 1 2 to 23- 1 4) • Schuller method-25 degrees caudad (Fig. 23- 1 5 ) • Lysholm method-35 degrees caudad (Fig. 23- 1 6) • Center the IR to the central ray.

Fig. 23- 1 3 Upright radiography: Henschen method.

C.R.

C.R.

Fig. 23- 1 4 Table radiography: Henschen method.

434

Petromastoid Portion

Fig. 23- 1 5 Axiolateral petromastoid portion: Schuller method. 25 degrees.

Fig. 23- 1 6 Axiolateral petromastoid portion: Lysholm method, 35 degrees.

435

Petromastoid Portion

Structures shown Henschen method

The Henschen I S-degree method demon­ strates the mastoid cells, mastoid antrum, lAM, and EAM (Fig. 23- 1 7). This approach was recommended by Henschen I and later by Cushjng2 for demonstrating tumors of the acoustic nerve. Schuller method

The SchUl ler 2S-degree method demon­ strates the pneumatic structure of the mas­ toid process, the mastoid antrum, the lAM and EAM, the sinus and dural plates, and, when present, the mastoid emissary vessel (Fig. 23- 1 8) . ' Henschen F : Die Akusticustumoren, eine neue Gruppe radiograph isch darstellbar H i mtumoren, Fortschr Roentgellstr 1 8:207, 1 9 1 2. 'Cushing H : Tumors oj the nervus aClIsticus, Philadelphia, 1 9 1 7, WB Saunders.

Fig. 23- 1 7 Axiolateral petromastoid portion: Henschen method, 1 5 degrees.

Mastoid antrum Internal and external acoustic meatuses Petrous portion Mastoid process

Mandibular condyle

Fig. 23- 1 8 Axiolateral petromastoid portion: Schuller method, 25 degrees.

436

Petromastoid Portion

Lysholm method

The Lysholm 35-degree method, I some­ times referred to as the Runstrom Il method, demonstrates the mastoid cells, mastoid antrum, EAM, labyrinthine area, and carotid canal ( Fig. 23- 1 9). Runstrom2 recommended that the expo­ sures be made with the mouth open for vi­ sualization of the petrous apex between the anterior wall of the EAM and the mandibular condyle. ' Lyshom E: Apparatus and technique for roentgen examination of the skull, Acta RadiaL 1 2(suppl):83, 1 93 1 . 2Runstrom G : A roentgenological study of acute and chronic otitis media, Acta Radial 1 7(suppl): I , 1 933.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Mastoid and petrous regions in center of radiograph • M astoid air cells lying posterior to petrous region • TMJ lying anterior to petrous region • Opposite mastoid and petrous regions not superimposing side of interest and projecting to a more inferior location as central ray angulation increases • Close beam restriction to mastoid and petrous regions

Fig. 23- 1 9 Axiolateral petromastoid portion: Lysholm method, 35 degrees.

437

Petromastoid Portion

'"

AXIOLATERAL OBLIQUE PROJECTION STENVERS METHOD Posterior profile

Image receptor: 8 x 1 0 inch ( 1 8 x

24 cm) Position of patient • Place the patient in the prone position,

or seat the patient before a vertical grid device. Position of part • Rest the patient's head on the forehead,

• Fig. 23-20 Axiolateral oblique projection demonstrating right petromastoid portion: poste­ rior profile, Stenvers method. •

•

_ 45"-----..

--M+-4r�-�r------< C.R.

1--+

*--;:::-< :..

C.R.

Fig. 23-21 Upright radiography. • •

nose, and cheek, with the side being ex­ amined closest to the IR. Adj ust the flexion of the patient's neck so that the IOML is parallel with the transverse axis of the I R . Using a protractor a s a guide, adjust the midsagittal plane of the head to form an angle of 45 degrees with the plane of the IR ( Figs. 23-20 to 23-22) . I n patients with brachycephalic (short front-to-back) skulls, the petrous ridges form an angle of approxi mately 54 de­ grees with the midsagittal plane of the head. Patients with this skull type re­ quire less than normal rotation of the midsagittal plane to place the petrous ridge parallel with the J R . I n patients with dolichocephalic ( long front-to­ back) skul ls, the petrous ridges form an angle of approximately 40 degrees with the midsagittal plane. Patients with this skull type require more rotation of the midsagittal plane to place the petrous ridge parallel with the IR. I mmobi lize the head. Respiration: Suspend.

Central ray • Directed 1 2 degrees cephalad. The cen­ C.R.

C.R.

Fig. 23-22 Table radiography. 438

tral ray enters about 3 to 4 i nches (7.6 to 10 cm) posterior and Y, i nch ( 1 .3 cm) i nferior to the upside EAM and exits about I i nch (2.5 cm) anterior to the downside EAM . • Center the I R to the central ray.

Petromastoid Portion

EVALUATION CRITERIA

Structures shown

The Stenvers method shows a profi le i m­ age of the petromastoid portion closest to the I R . When the patient is correctly po­ sitioned, the petrous pyramid of i nterest is parallel with the plane of the I R (Fig. 23-23 ) . The resultant i mage demon­ strates the petrous ridge, the cel lular structure of the mastoid process, the mastoid antrum, the area of the tympanic cav ity, the bony labyrinth, the internal acoustic canal, and the cell ular structure of the petrous apex.

The fol lowing should be clearly demon­ strated: • Petromastoid portion in profi le without distortion. • Lateral border of skull to lateral border of orbit. • Petrous ridge extended to a point ap­ proximately two thirds up lateral border of orbit.

•

•

• •

Mastoid process in profi le below mar­ gin of cranium. (Air cel ls are not well visualized when internal aspects of the petrosa are properly exposed.) Posterior margin of mandibular ramus superimposing lateral border of cervi­ cal column. Mandibular condyle projecting over the atlas near the petrosa. Close beam restriction to the petrous pyramid and mastoid region.

Internal acoustic canal Arcuate eminence

Mastoid air celis

External acoustic meatus and canal Mandibular condyle

Mastoid process

Fig. 23-23 Axiolateral oblique petromastoid portion: posterior profile, Stenvers method ,

439

Petromastoid Portion

.. AXIOLATERAL OBLIQUE PROJECTION ARCELIN METHOD Anterior profile

The Arcelin method is particularly useful in children and in adults who cannot be placed in the prone or seated-upright posi­ tion for the Stenvers method. Thi s projec­ tion is the exact opposite of the Stenvers method, and the petromastoid portion is more magnified. Image receptor: 8 x 1 0 i nch ( 1 8 x

24 cm) Position of patient • •

Fig. 23-24 Axiolateral oblique demonstrating right petromastoid portion. Anterior profile, Arcelin method.

C.R.

C.R.

Fig. 23-25 Table radiography.

...--- 45'

_-�.(. C.R. t---f...,.4-..,...,j-�--I------< C.R.

Fig. 23-26 Upright radiography. 440

Place the patient in the supine position. Center the midsagittal plane of the pa­ tient's body to the midline of the radio­ graphic table.

Petromastoid Portion

Position of part •

•

EVALUATION CRITERIA

Central ray

Rotate the patient's face away from the Directed at an angle of 1 0 degrees cau­ side being exami ned so that the mid­ dad. The central ray enters the temporal sagittal plane forms an angle of 45 de­ area at a point approximately I i nch grees with the plane of the I R. (2.5 cm) anterior to the EAM and % Adj ust the flexion of the patient's neck inch ( 1 .9 cm) above it. Center the IR to the central ray. o that the IOML is perpendicular to the plane of the IR (Figs. 23-24 to 23-26). In patients with brachycephalic (short Structures shown front-to-back) skulls, the petrous ridges The anterior-profi le Arcelin method (Fig. form an angle of approximately 54 de­ 23-27), the exact reverse of the Stenvers grees with the midsagittal plane. Patients method, demonstrates the petrous portion with this skull type require less than nor­ of the temporal bone farthest from the IR. mal rotation of the midsagittal plane to place the petrous ridges paralJel with the l R. In patients with dolichocephalic (long front-to-back) skulls, the petrous ridges form an angle of approximately 40 degrees with the midsagittal plane. Patients with this skull type require more rotation of the midsagittal plane to place the petrous ridge parallel with the IR. I mmobi lize the head. Respiration: Suspend. Internal acoustic canal ------=:i! •

•

•

• •

The fol lowing should be clearly demon­ strated: • Petromastoid portion in profi le. • Lateral border of skull to lateral border of orbit. • Petrous ridge lying horizontally and at a point approximately two thirds up lat­ eral border of orbit. • Mastoid process in profi le below mar­ gin of cranium. (Air cells are not well visualized when petrous pyramid is properly exposed. ) • Posterior surface o f mandibular ramu parallel to lateral surface of cervical vertebrae. • Mandibular condyle projected over the atlas near the petrous pyramid. • Close beam restriction to petrous pyra­ mid and mastoid region.

Petrous ridge �-=-'=== Mastoid antrum External acoustic meatus and canal Mandibular condyle Mastoid process

Fig. 23-27 Axiolateral oblique petromastoid portion, anterior profile: Arcelin method. 44 1

Petromastoid Portion AXIOLATERAL OBLIQUE PROJECTION MAYER M ETHOD NOTE: The axiolateral oblique projection or Mayer method was originally described using a nongrid technique. The original technique has been modified to use a grid for i mproved radiographic qual ity. Image receptor: 8 x 1 0 inch ( 1 8 X 2 4 cm) Position of patient • Place the patient in the supine position,

or seat the patient lateral ly before a ver­ tical grid device. • Tape the auricles forward. Fig. 23-28 Axiolateral oblique petromastoid portion: Mayer method.

midsagittal plane 45 degrees to the plane of the IR, with the side of i nterest positioned closest to the IR. This places the petrous pyramid of interest perpen­ dicular to the JR. • Depress the patient's chin enough that the IOML is parallel with the transverse axis of the JR (Figs. 23-28 to 23-30). • I mmobilize the head. • Respiration: Suspend.

C.R.

Fig. 23-29 Table radiography.

-+- C .R.

� _ _

Fig. 23-30 Upright radiography.

442

Position of part • Rotate the patient's head to place the

Petromastoid Portion

Central ray • Directed at an angle of 45 degrees cau­

dad to exit the EAM closest to the I R . • Center the I R t o the central ray. Structures shown

An axiolateral oblique projection of the petrosa in the direction of its long axis demonstrates the EAM, tympanic cavity and ossicles, epitympanic recess, aditus, and mastoid antrum closest to the IR (Fig. 23-3 1 ).

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Petrosa inferior to mastoid air cel ls • EAM visible adjacent and anterior to petrosa • TMJ vi sible anterior to EAM • Auricle of ear not superimposing pet­ rosa or mastoid air cells • Close beam restriction to the petrous region

Mastoid air cells

Mastoid antrum External acoustic canal Labyrinth Mandibular condyle

Fig. 23-31 Axiolateral oblique petromastoid por­ tion: Mayer method.

443

Petromastoid Portion

Modifications

Mayer, I and later Owen,2 stated that it is sometimes advantageous to vary head ro­ tation and/or central ray angulation. Many modifications of the Mayer method, each attributed to Owen, have been used. In the Owen modification cited by Pendergrass, Schaeffer, and Hodes,3 the patient's head is adjusted so that the mid­ sagittal plane is 40 degrees from the I R . The tabletop I R and the head are angled to degrees caudally, and the central ray is angled 28 degrees caudally (a total caudal angulation of 38 degrees) (Fig. 23-32). ' Mayer EG: The technic of the roentgenologic ex­ amination of the temporal bone, Radiology 7:306, 1 926. 'Owen GR: A simplified method of producing the axial view of Mayer in chronic mastoiditis and aU.ic cholesteatoma, AJR 57:260, 1 947. ]Pendergrass EP, Schaeffer J P, Hodes PJ : The head and neck in roentgen diagnosis, ed 2, Springfield, I l l , 1 956, Charles C Thomas.

444

In the Owen modification described by Etter and Cross, I the midsagittal plane of the head is adj usted at an angle of 30 de­ grees to the IR. The central ray is then di­ rected 25 to 30 degrees caudally ( Fig. 2333). I n the Owen modification described by Compere,2 the head rotation is varied from 30 to 45 degrees to the plane of the IR, and the central ray is directed caudally at an angle of 30 degrees. ' Etter LE, Cross LC: Projection angle variations re­ quired to demonstrate the middle ear, Radiology 80:255, 1 963. 'Compere WE: The roentgenologic aspects of tym­ panoplasty, AJR 81 :956, 1 959.

Petromastoid Portion

Fig. 23-32 Axiolateral oblique petromastoid region: Owen-Pendergrass modification. with head rotated 40 degrees and total caudal central ray angulation of 38 degrees.

Fig. 23-33 Axiolateral oblique petromastoid region: Owen-Etter-Cross modification. with head rotated 30 degrees and caudal central ray angulation of 30 degrees.

445

Petromastoid Portion

AP AXIAL PROJECTION TOWNE M ETHOD Image receptor: 8 x 1 0 inch ( 1 8 X

24 cm) lengthwise Position of patient

Place the patient in either the supine or seated-upright position. • Center the midsagittal plane of the body to the midline of the grid device.

•

Position of part

Adj ust the patient's head to place the midsagittal plane perpendicular to the midline of the grid. • Flex the patient's neck enough to place the orbitomeatal line (OML) perpendic­ ular to the plane of the I R . • When the patient's head cannot be flexed to this extent, adjust it to place the IOML perpendicular to the IR and then compensate with a 7-degree in­ crease in the caudal angulation of the central ray (Figs. 23-34 to 23-36). • I mmobilize the head. Respiration: Suspend.

•

Fig. 23-34 AP axial petromastoid portion: Towne method.

--..----,�C. R. -r_--:::I',,- C.R.

37'

•

Central ray

Directed at a caudal angle of 30 degrees to the OML or 37 degrees to the IOML. The central ray enters approximately 2� inches (6.4 cm) above the nasion and passes through at the level of the EAM . • Center the I R to the central ray.

•

Fig. 23-35 Upright radiography.

C.R.

Fig. 23-36 Table radiography,

446

Petromastoid Portion

EVALUATION CRITERIA

Structures shown

This projection shows the petrosas pro­ jected above the base of the skull (Fig. 23-37). It demonstrates the internal acoustic canals, arcuate eminences, labyrinths, mas­ toid antrums, and middle ears. The dorsum sellae is seen within the foramen magnum.

The fol lowing should be clearly demon­ strated: • Entire petrous and mastoid regions • Distance from lateral border of skull to l ateral margin of foramen magnum equal on both sides • Symmetric petrous pyramids • Dorsum sellae visible within foramen magnum • Close beam restriction to the petrous and mastoid regions

NOTE: Radiographic tomography or CT is often employed in examinations of the ear. These studies may be made with the patient's head ad­ justed for the AP projection. When indicated, further studies may be made in the lateral posi­ tion or in another selected petrosal position. Additional information on radiographic tomog­ raphy, including radiographs of the inner ear, is provided in Chapter 29; further information on computed tomography i given in Chapter 33.

Dorsum sellae Arcuate eminence Internal acoustic canal Labyrinth (cochlea. semicircular canal. vestibule) Mastoid air cells

Fig. 23-37 AP axial petromastoid portion: Towne method.

447

Petromastoid Portion

SUBMENTOVERTICAl PROJECTION AND HI RTZ MODIFICATION The goal of the basilar projection for the petromastoid portion is to project the long axis of the EAMs, the tympanic cavities, and the osseous part of the auditory (eu­ stachian) tubes i mmediately behind the mandibular condyles. Therefore the cen­ tral ray is projected perpendicular to the OML rather than the IOML, as in the sub­ mentovertical (SMV) projection for the cranium. Image receptor: 8 x 10 inch ( 1 8 X

24 cm) Position of patient Fig. 23-38 Upright radiography: SMV petromastoid portion. with central ray perpendicular to OML.

--_< C.R. t-------e�:....... ....::: '--.::

Fig. 23-39 Upright radiography: central ray perpendicular to OML.

C.R.

Fig. 23-40 Table radiography: central ray perpendicular to OML. 448

• Seat the patient before a vertical grid

device, or place the patient in the supine position with the trunk elevated enough to permit full extension of the neck. When the patient is in the supine position, the knees should be flexed to relax the abdominal muscles.

Petromastoid Portion

Position of part • Center the midsagittal plane of the

body to the midline of the grid. • Rest the patient's head on the vertex,

and adjust it so that the mjdsagittal plane is perpendicular to the midline of the grid. • Position the patient using either of two basic approaches: ( I ) adjust the exten­ sion of the neck so that the OML is par­ allel with the plane of the IR (Figs. 23-38 to 23-40) or (2) when the neck cannot be fully extended, angle the central ray an­ teriorly until it is perpendicular to the OML (Fig. 23-4 1 ). • I mmobi lize the head. • Respiration: S uspend.

Central ray • For the SMV projection, direct the cen­

tral ray perpendicular to the OML (Figs. 23-38 to 23-4 J ) and centered to the sagittal plane of the throat at the level of the EAMs. • Center the I R to the central ray.

Fig. 23-41 Supine: SMV petromastoid portion with central ray perpendicular to OML.

449

Petromastoid Portion

Hirtz modification • For the Hirtz modification, 1 direct the

central ray to a point midway between and 1 inch (2.5 cm) anterior to the EAMs at an anterior angle of 5 degrees (Figs. 23-42 to 23-44).

Structures shown

A symmetric axial projection of the pet­ rosas demon trate the mastoid processes, labyrinths, EAM, tympanic cavities, and acoustic ossicles (Fig. 23-45) . ' H i rtz EJ: Quelques nouveaux details sur l a radi­ ographie de la base du crane, 8111/ Soc Radiol Med (Pari ) 1 0: 1 1 0, 1 922.

Fig. 23-42 Upright radiography: SMV petromastoid portion. Hirtz modification. with central ray 5 degrees to OML.

C. R. 5°

r--jl�d-�=-
450

Fig. 23-44 Table radiography: Hirtz modification.

Petromastoid Portion

EVALUATION CRITERIA

The fol low ing should be clearly demon­ strated: • Mandibular condyles anterior to external acoustic canals and petrous pyramjds • Organs of hearing within petrosae • Di tance from lateral border of skull to mandibular condyles equal on both sides • Symmetric petrosas • Close beam restriction to the petrous region

Condyle External acoustic canal Cochlea Antrum Mastoid process Semicircular canal Dens (odontoid process]

Fig. 23-45 SMV petromastoid region.

45 1

Styloid Processes

PA AXIAL PROJECTION CAHOON M ETHOD Image receptor: 8 x l O inch ( 1 8 x

24 cm) Position of patient • Place the patient in the seated-upright

or prone position. Position of part • Rest the patient's forehead and nose on

• • Fig. 23-46 PA axial styloid processes: Cahoon method. • •

the grid device, and adjust the forehead and nose so that the midsagittal plane i s perpendicular t o the mjdline o f the grid. Center the IR to the nasion. Adjust the flexion of the patient's neck so that the OML is perpendicular to the plane of the IR (Figs. 23-46 to 23-48). I mmobil ize the head. Respiration: Suspend.

Central ray • Directed to the nasion at an angle of 25

degrees cephalad.

I-----I-...-,...... �-< C.R.

-L-

----"'(' " C.R.

-

Fig. 23-47 Upright radiography.

C.R. C.R.

Fig. 23-48 Table radiography. 452

Styloid Processes

EVALUATION CRITERIA

Structures shown

The Cahoon method demonstrates a sym­ metric i mage of the styloid processes of the temporal bones projected withjn or just above the maxillary sinuses (Fig. 23-49).

The following should be clearly demon­ strated: • Temporal styloid processes free of su­ perimposition from frontal bone, occip­ ital bone, and coronoid processes of the mandible • No rotation of head

Coronoid process

Fig. 23-49 PA axial styloid processes (arrows): Cahoon method. 453

J ugular Foramina

SUBMENTOVERTICAL AXIAL PROJECTION KEMP HARPER M ETHODl E RASO MODIFICATION2 Image receptor: 8 x 1 0 inch ( 1 8 X

24 C Ol ) Kemp Harper method Position of patient • For the SMV axial projection, place the

Fig. 23-50 SMV axial jugular foramina: Kemp Harper method.

patient in the supine or seated-upright position. In the supine position, it may be necessary to elevate the patient's trunk to permit ful l extension of the head. The head can be extended more fully and more comfortably from the seated-upright position. Position of part

C.R.

• Center the midsagittal plane of the

body and head to the midline of the grid device. • Rest the patient's head on the vertex, and adjust it so that the OML is parallel with the plane of the IR and the mid­ sagittal plane is perpendicular to the I R plane (Figs. 23-50 to 23-52). • Immobil ize the head. • Respiration: Suspend. Central ray • Directed I i nch (2.5 Col) distal to the

mandibular symphysis at a 20-degree posterior angle. The central ray should be paral lel to a l ine passing through or just distal to the EAM (Fig. 23-5 3 ) . • Center the I R t o the central ray. Fig. 23-51 Upright radiography.

Fig. 23-52 Table radiography.

' Kemp Harper RA: Glomus jugulare rumors of the temporal bone, J Fac Radiologists 8:325, 1 957. 'Eraso ST: Roentgen and clinical diagnosis of glo­ mus jugulare tumors, Radiology 77:252, 1 96 1 .

Coronoid process

Mandibular angle

Dens (odontoid process) Fig. 23-53 SMV axial jugular foramina (arrowheads): Kemp Harper method. 454

J ugular Foramina

E raso modification 1

The Eraso modification is not as demand­ ing a position for the patient to assume as is the SMV Kemp Harper method. Position of part •

•

Place the patient in a position similar to that for the Kemp Harper method, with the OML placed at an angle of 25 de­ grees from the plane of the IR (Figs. 23-54 to 23-56) . Adj ust the midsagittal plane o f the head perpendicular to the I R .

Central ray

Directed perpendicular to the midpoint of the I R, entering approximately 2 inches (5 cm) distal to the mandibular symphysis. • Center the IR to the central ray.

•

Fig. 23-54 Eraso modification of Kemp Harper method.

Structures shown

Both SMV projections (see Fig . 23-53 and 23-5 7 ) demonstrate the j ugular foramina projected at or near the level of the angles of the mandible. When a pa­ tient with a prominent mandible is bei ng examined, the angulation of the central ray may be increased from 5 to 1 0 degrees caudally. The Eraso modification projects the jugular foramen at an angle 5 degrees greater than the Kemp Harper method. EVALUATION CRITERIA

The following should be clearly demon­ strated: • Jugular foramina free of superimposi­ tion from mandible • Equal di stance from the angle of the mandibles to the lateral border of the skull on both sides

C.R.

Hr-----=..:��--::"I""---_< C.R.

Fig. 23-55 Upright radiography: Eraso mod­ ification.

Fig. 23-56 Table radiography: Eraso modifi­ cation.

NOTE: Strickler2 suggested a modification of the Eraso method wherein the neck is extended until a line passing through the infratragal notch and a point 2 cm distal to the mandibular symphysis is perpendicular to the plane of the film. The central ray coincides with this line. IEraso ST: Roentgen and clinical diagnosis of glo­ mus jugulare tumors, Radiology 77:252, 1 96 1 . 'Strickler J M : New and simple techniques for demonstration of the jugular foramen, AJR 97:60 1 , 1 966.

Mandibular angle

Fig. 23-57 Eraso modification of Kemp Harper method, demonstrating jugular foramina (arrows).

455

Hypoglossal Canal

AXIOLATERAL OBLIQUE PROJECTION M I LLER METHOD Anterior profile

The Miller method is used to delineate the hypoglossal canal in a patient with a hy­ poglossal (twelfth cranial) nerve tumor. The hypoglossal canals, one on each side, pass through the lateral part of the occipi­ tal bone at the base of the anterior limb of the occipital condyle. These canals trans­ mit the twelfth cranial nerves, which are the motor nerves of the tongue. Image receptor: 8 x 1 0 inch ( 1 8 X 24 cm) Position of patient Fig. 23-58 Axiolateral oblique hypoglossal canal. anterior profile: Miller method.

•

Place the patient in the supine position, or seat the patient before a vertical grid device.

Position of part •

C.R.

C.R.

Rotate the midsagittal plane of the head 45 degrees away from the side being

•

examined. Adjust the flexion of the patient's neck so that the IOML is parallel with the transverse axis of the IR (Figs. 23-58 to

23-60). • I mmobilize the head, and ask the patient

to open the mouth as wide as possible. Respiration: Have the patient softly phonate ah-h-h to immobilize the mouth in the open position, or ask the patient to suspend respiration for the exposure.

Fig. 23-59 Table radiography.

Y-

::::..( :oo C.R.

-

1\-o---fr-h'lP!..-+ .- -------( C.R.

Fig. 23-60 Upright radiography.

456

Hypoglossal Canal

Central ray • Directed at an angle of 1 2 degrees cau­

dad to enter I inch (2.5 cm) directly an­ terior to, and Y2 inch ( 1 .3 cm) inferior to, the level of the EAM on the side far­ thest from the I R . • Center the I R t o the central ray. Structures shown

An i mage of the hypoglossal canal is shown (Fig. 23-6 1 ). The mandibular condyle is projected inferior and ante­ rior to the canal when the patient can open the mouth wide enough. Because of normal anatomic variations, the ideal i mage is not always obtained (see Figs. 23-58 to 23-6 1 ).

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Hypoglossal canal in profi le inferior to petrous bone • Mandibular condyle not superimposing hypoglossal canal

NOTE: Kirdani ' and Val vassori and Kirdani2 recommended that the hypoglossal canal be examined by tomographic sectioning in the SMV, semiaxial AP, and Stenvers positions. These studies also provide excellent demon­ stration of the jugular foramina. ' Kirdani M A : The normal hypoglossal canal, AJR 99:700, 1 967. 2Valvassori E, Kirdani M A : The abnormal hypoglos­ sal canal, AJR 99:705, 1 967.

Petrous ridge

Hypoglossal canal Mastoid process

Fig. 23-61 Axiolateral oblique hypoglossal canal (arrow), ante­ rior profile: Miller method. 457

24 T E R E S E M c S H A N E R OT H

OUTLINE

EXPOSURE TECHNIQUE CHART. • • •

SUM MARY OF PROJ ECTIONS

P ROJECTIONS, POSITIONS & M ETHODS

Breast

Craniocaudal

IMPLANT

Breast

Craniocaudal

IMPLANT DISPLACED

486

Breast

Mediolateral

IMPLANT

487

Breast

Mediolateral

IMPLANT DISPLACED

495

Breast

Variable

SPOT COMPRESSION

496

Breast

Variable

MAGNIFICATION

498

Breast

Mediolateral

500

Breast

Lateromedial

502

Breast

Exaggerated craniocaudal

504

Breast

Craniocaudal

CLEAVAGE

506

Breast

Craniocaudal

ROLL LATERAL

506

Breast

Craniocaudal

ROLL MEDIAL

508

Breast

510

Breast

Caudocranial

51 2

Breast

Mediolateral

51 4

Breast

Lateromedial

516

Breast

Superolaterai to inferomedial oblique

AXILLARY TAIL

Icons In the Essential column indicate projections frequently performed in the United States and Canada. Students should be competent in these projections.

Principles of Mammography I NTRODUCTION AND HISTORICAL DEVELOPMENT The worldwide incidence of breast cancer is increasing. In the United States, one i n eight women who l ive t o the age o f 95 year will develop breast cancer sometime during their lifetime. Breast cancer is one of the most common malignancies diag­ nosed in women, and it is the leading cause of cancer deaths in females between the ages of 1 5 and 54 years. J Only lung cancer kills more women overall . Research has fai led to reveal the precise etiology of breast cancer, and only a few major fac­ tors, uch as family history, are known to increase a woman's risk of developing the clisease. Yet most women who c1evelop breast cancer have no family history of the disease. Despite its frequency, breast cancer is one of the most treatable cancers. Because this malignancy is most treatable when it is detected early, efforts have been di­ rected toward developing breast cancer screening and early detection methods. Mammography is the most important innovation in breast cancer control since the radical mastectomy was introduced by Halstead in 1 898. The primary goal of mammography is to detect breast cancer before it is palpable. The combination of early detection, diagnosis, and treatment has resulted in a steady i ncrease in sur­ vival rates. In fact, the overall mortal ity rate for breast cancer has finall y decreased for American women.

Before the radical mastectomy was i n­ troduced, breast cancer was considered a fatal disease. Fewer than 5% of patients survived 4 years after diagnosis, and the local recurrence rate for surgically treated breast cancer was higher than 80%. Radical mastectomy increased the 4-year survival rate to 40% and reduced the rate of local recurrence to approximately 1 0%. Although this was certainly a great step forward, no additional improvement i n breast cancer survival rates occurred over the next 60 years. However, some of the principles of breast cancer management were developed and remain valid today: I . Patients in the early stage of the dis­ ease respond well to extensive surgery. 2. Patients with advanced disease do poorly. 3. The earlier the diagnosis, the better the chances of survival.

Reflecting the e principles, the theory of removing all palpable breast masses in hopes of finding earlier cancers was devel­ oped, and it was recognized that careful physical examination of the breast could detect some early breast cancers. However, most patients with breast cancer still were not diagnosed until their disease was ad­ vanced. This fact, coupled with the dismal breast cancer survival statistics, high­ lighted the need for a tool for the early de­ tection of breast cancer. Mammography fi lled that need (Fig. 24- 1 ).

I American Cancer Society: Breast cancer facts & figures 1 99912000, http://www.cancer.orgl (accessed April 200 1 ).

Fig. 24- 1 A four-image, bilateral mammogram of a 37-year-old woman. Craniocaudal and mediolateral oblique projections demonstrate normal. symmetric breast parenchyma.

46 1

In 1 9 1 3, Soloman, a German physician, reported the radiographic appearance of breast cancers. Using radiographic studies of cancerous breasts removed at surgery, he described the mechanism of how brea t cancer spread. The first published radi­ ograph of a living person's breast, made by Klei nschmidt, appeared i n a 1 927 German medical textbook on malignant tumors. Although publications on mammography appeared in South America, the United States, and Europe during the 1 930s, the use of mammography for the diagnosis of breast cancer received little clinical inter­ est . A few pioneers, including LeBorgne in Uruguay, Gershon-Cohen in the United States, and Gros in Germany, published excellent comparisons of mammographic and pathologic anatomy and developed some of the clinical techniques of mam­ mography. At that time the significance of breast microcalcifications was also well understood.

By the mid- 1 950s, mammography was considered a rel iable cli nical tool because of such refinements as low-kilovoltage x­ ray tubes with molybdenum targets and high-detai l , i ndustrial-grade x-ray film. During this time, Egan in the United States and Gros in Germany popularized the use of mammography for diagnosing and evaluating breast cancer. Breast xe­ rography was introduced in the 1 960s and was popularized by Wolfe and Ruzicka. Xerography substantially lowered the ra­ diation dose received by the patient com­ pared with the dose received using i ndus­ trial grade x-ray film (Fig. 24-2). Because many physicians found the xerographic i mages easier to understand and evaluate, xeromammography became widely used for evaluating breast disease. The first at­ tempts at widespread population screen­ i ng began at this time.

Fig. 24-2 Xeromammogram. Craniocaudal projection of the breast of 51 -year-old woman with carcinoma (arrow). Xeromammography has been replaced by screen-film mam­ mography systems.

462

The combination of higher-resolution, faster-speed x-ray film and an i ntensifying screen was first i ntroduced by the duPont Company. As a result radiation exposure to the patient was reduced even more. I mproved screen-film combinations were developed by both Kodak and duPont in 1 975. By this time, extremely high-quality mammography images could be produced with very low patient radiation exposures. Since 1 975, faster lower-dose films, mag­ nification techniques, and grids for scatter reduction have been introduced. It is now known that high-quality mammography, careful physical examination, and monthly breast self-examination (BSE) can result in the detection of breast cancer at an early stage-when it is most curable. The Breast Cancer Detection Demon­ stration Project (BCDDP) was i mple­ mented i n 1 973. I n this project, 280,000 women underwent annual screening for breast cancer for 5 years at 29 locations throughout the United States. Organized by the American Cancer Society (ACS ) and the National Cancer I nstitute ( NCI ) , this project demonstrated unequivocally that screeni ng, physical examination, mammography, and BSE could provide an early diagnosis. I n the BCDDP, more than 4 1 % of all the cancers were found using only mammography, and an even greater proportion of early breast cancers were found only with mammography. The BCDDP was not designed to demonstrate that early detection of breast cancer would lead to increased survival rates, but defi­ nite evidence from carefully controlled studies in the Netherlands, Sweden, and Germany showed that early diagnosis of breast cancer leads to an increase in cur­ ability. In the United States, the Health I nsurance Plan study in New York City performed mammography screen ings on women over 50 years of age and demon­ strated the same benefits in reduced mor­ tal ity rates after early diagnosis of breast cancer.

Mammography must be performed well to be fully effective. I n 1 992 the Mammo­ graphy Quality Standards Act (MQSA) was implemented to mandate the mainte­ nance of high-quality breast cancer screen­ ing programs. Although the American College of Radiology (ACR) had been a proponent of high standards in breast imag­ ing since 1 967, it was not until 1 994 that mammography became the only radio­ graphic examination to be full y regulated by the federal government. The MQSA re­ quires formal training and continuing edu­ cation for all members of the breast i mag­ ing team. In addition, imaging equipment mu t be inspected regularly, and all quality assurance activities must be documented. Facilities are aI 0 required to identify the individuals who are responsible for com­ municating mammogram results with the patient, providing fol low-up, tracking pa­ tients, and monitoring outcomes. The goal of the MQSA is for high-quality mammog­ raphy to be pelformed by those most qual­ ified to do so and by those who are willing to accept full responsibility for providing that service with continuity of care.

RISK VERSUS BENEFIT I n the mid- 1 970s the public perception was that radiation exposure from diagnos­ tic x-rays would actually induce more breast cancers than would be detected. Although this perception is false, fear of radiation exposure sti l l causes some women to refuse mammography, and many women who undergo the examina­ tion are concerned about exposure levels and the resultant risk of carcinogenesis. To assuage these fears, the radiographer must understand the relationship between breast ilTadiation and breast cancer, as well as the relative risks of mammography, in l ight of the natural incidence of breast cancer and the potential benefit of the examination. No direct evidence exists to suggest that the small do es of diagno tic x-rays used in mammography can induce breast can­ cer. It has been demonstrated, however, that large radiation doses can increase the incidence of breast cancer and that the risk is dose dependent. The evidence to support the increased risk of breast cancer from breast irradiation comes from studies of three groups of women in whom the inci­ dence of breast cancer increased after they were exposed to large doses of radiation.

These groups are as follows: ( I ) women exposed to the atomic bombs at Hiroshima and Nagasaki; (2) women with tuberculo­ sis who received multiple fluoroscopic ex­ aminations of the chest; and (3) women who were treated with radiation for post­ partum mastitis. However, the radiation dose received by these women (600 to 700 rads) was many times higher than the dose received from mammography. Mean glandular dose (MGD) provides the best indicator of radiation risk to the patient. In 1 997 the average MGD for a two-view screen-fi lm-grid mammogram for all facilities in the United States in­ spected under MQSA was 320 mrad . ' Using that level a s a gauge, the lifetime risk of mortality from mammography­ induced radiation is 5 deaths per I million patients. In other terms, the risk received from having an x-ray mammogram using a screen-film combination is equivalent to smoking several cigarettes, driving 60 mi les in an automobile, or being a 60year-old man for 10 minutes. An important observation in the prev i­ ously mentioned population studies is that the breast tissue of females in their teenage years to early 20s seems to be much more sensitive to radiation than the breast tissue of women over 30 years. Because breast irradiation is a concern, radiologic exami­ nations need to be performed with only the radiation dose that is necessary for provid­ ing accurate detection. ' H aus AG: Screen-Film and digital mam mography i mage quality and radiation dose considerations, Radial elin North Am 38:87 1 , 2000

463

BREAST CANCER SCREENING The frequency with which women should undergo screening mammography de­ pends on their age and personal risk of developing breast cancer. The current rec­ ommendations from the American Cancer Society and the ACR are that all women over the age of 50 years should u ndergo annual mammography. Women between ages of 40 and 49 years should have a mammogram every year or every other year. A baseline examination made some­ time before the onset of menopause is useful for subsequent evaluations. H igh­ risk patients should begin undergoing screening mammography at an earlier age and more frequent intervals. The term screening mammography i s applied t o a procedure performed o n an asymptomatic patient or a patient who presents without any known breast prob­ lems. For a procedure to be used as a screening method, it must meet the fol ­ lowing criteria: I . It must be simple. 2. It must be acceptable. 3. It must demonstrate high sensitivity. 4. It must demonstrate high specificity. 5. It must be reproducible. 6. It must be cost-effective. 7. It must have a low risk-versus-benefit ratio. Mammography is a relatively simple procedure that takes only about 1 5 minutes to complete. The acceptabi lity of mam­ mography, which is the only radiographic procedure used to screen cancer, has been confirmed in numerous studies. However, mammography cannot detect all cancerous lesions. Therefore breast cancer detection should include an annual clinical breast examination and monthly BSEs. Even when mammography is performed prop­ erly, approximately 1 0% of cancers re­ main radiographically occult, particularly in the dense breast and the augmented breast. Even so, mammography has greater sensitivity and specificity for de­ tecting breast tumors than any other cur­ rently available noninvasive diagnostic technique. When compared with magnetic resonance i maging (MRl), sonography, and digital techniques, mammography is more cost effective and more reproducible when quality control standards are main­ tained. Yet, mammography must be per­ formed properly to maintain these charac­ teristics. As with other imaging modalities, high-quality mammography requires an extremely dedicated staff with the appro­ priate training and expertise. 464

Breast cancer screening studies have shown that early detection is essential to reducing mortality and that the most ef­ fective approach is to combine clinical breast examination with mammography at directed i ntervals. A lthough massive screening efforts initi ally could appear cost-prohibitive, the actual cost of screen­ ing is, in the long term, much less than the expenses involved in caring for patients with advanced breast disease. The preceding discussion describes the screening of patients who do not have sig­ nificant breast symptoms. All patients with clinical evidence of significant or poten­ tially significant breast disease should un­ dergo a diagnostic mammogram and subse­ quent workup as necessary. Diagnostic mammograms are problem-solving exami­ nations in which specific projections are obtained to rule out cancer or to demon­ strate a suspicious area seen on the routine screening projections. They are also indi­ cated if a woman presents with a palpable mass or other symptom. The area of inter­ est may be better demonstrated using im­ age enhancement methods such as focal spot compression and a magnification tech­ nique. Further workup may be necessary if mammography does not demonstrate a cor­ relative mass. Alternative imaging modalj­ ties such as sonography are often used to complete a successful workup. The radiol­ ogist and radiographer direct and conduct the diagnostic mammogram to facilitate an accurate interpretation. A lthough most diagnostic mammo­ grams conclude with probable benjgn findings, some women are asked to return for subsequent mammograms in 3 or 6 months to assess for interval changes. Other women must consult with a surgeon about possible options such as fine-needle aspiration biopsy (FNA B ) or excisional biopsy. A lthough an excel lent tool for detect­ ing breast cancer, mammography does not diagnose breast cancer. Some lesions may appear consistent with malignant disease but turn out to be completely be­ nign conditions. Therefore breast cancer can be diagnosed only by a pathologist through the evaluation of tissue extracted from the lesion. After interpreting the di­ agnostic workup, the radiologist must carefully determine if surgical interven­ tion is warranted.

RISK FACTORS Assessing a woman's risk for developing breast cancer is a complicated process. An accurate patient history must be elicited to identify the potential individual risk fac­ tors . The radiologist considers these known risks after interpreting the mam­ mogram. Except for gender, factors that are known to influence the development of breast cancer include age, hormonal history, and family hjstory. Age

The i ncidence of breast cancer increases with age. Hormonal history

Hormones influence the glandul ar tissue of the breast during breast development, pregnancy, and lactation; however, hor­ mone levels dec l i ne at the onset of menopause. As a result, the glandular breast tissue is more sensitive to carcino­ gens during menarche. H igh-risk women include those with early menses (begin­ ning before the age of 1 2 years), late menopause (occurring after 52 years of age), first birth after age 30 years, and nul­ l iparity. Family history

A woman whose daughter, sister, or mother previously developed breast cancer, espe­ cially at an early age, is at higher risk of de­ veloping the disease. However, studies have shown that only 1 3 .6% of known breast cancers are found in women with a family history of the rusease. Furthermore, a true genetic disorder has been identified in only 5% to 1 0% of women with breast cancer. I In 1 994 researchers isolated two breast cancer genes-BRCA I and B RCA2. Subsequently, commercial screening tests were developed. However, the accuracy of these tests has not yet been cHnically ac­ cepted. In addition, widespread genetic test­ ing raises ethical concerns associated with identifying appropriate canrudates for ge­ netic screening and determining what is done with the information derived from the testing. INational Cancer Lnstitute CancerNet. http://www. cancernet.nci.nih .gov/(accessed April 200 I ).

Breast The terms breast and mammary gland are often used synonymously. Anatomy text­ books tend to use the term mammary gland, whereas radiography textbooks tend to use the term breast. The breasts ( mammary glands) are lobulated glandular structure located within the superficial fascia of the anterolateral surface of the thorax of both males and females. The mammary glands divide the superficial fascia into anterior and posterior compo­ nents. Therefore the mammary tissue is completely surrounded by fascia and is en­ veloped between the anterior and posterior layers of the superficial fascia. [n females, the breasts are secondary sex characteris­ tics and function as accessory glands to the reproductive system by producing and se­ creting milk during lactation. In males, the breasts are rudimentary and without func­ tion. Male breasts are only rarely subject to abnormalities, such as neoplasms, that require radiologic evaluation.

Female breasts vary considerably in size and shape, depending on the amount of fat and glandular tissue and the condi­ tion of the suspensory ligaments. Each breast is usually cone-shaped, with the base or posterior surface of the breast overlying the pectoralis major and serra­ tus anterior muscles. These muscles ex­ tend from the second or third rib inferiorly to the sixth or seventh rib and from near the lateral margin of the sternum laterally toward the anterior axil lary plane. An ad­ ditional portion of breast tissue, the axil­ lary prolongation or axillary tail, extends from the upper lateral base of the breasts into the axillary fossa ( Fig. 24-3). The breast tapers anteriorly from the base, ending in the nipple that is sur­ rounded by a circular area of pigmented skin called the areola. The breasts are supported by Cooper 's ligaments, suspen­ sory l igaments that extend from the poste­ rior layers of the superficial fascia through the anterior fascia into the subcutaneous tissue and skin. It is the condition of these ligaments, and not the relative fat content, that gives the brea ts their firmness or lack of firmness.

The adult female breast consists of 1 5 to 20 lobes, which are distributed so that more lobes are superior and lateral than inferior and medial. Each lobe is divided into many lobules, which are the basic structural units of the breast. The lobules contain the glandular elements, or acini. Each lobule consists of several acini, a number of draining ducts, and the inter­ lobular stroma or connective tissue. These elements are part of the breast parenchyma and participate in hormonal changes. By the l ate teenage years to early 20s, each breast contains several hundred lobu les. The lobules tend to decrease in size with i ncreasing age and particularly after preg nancy-a normal proces cal led involution.

!!!!!:--!"--- Pectoralis minor

Axillary tail of breast

anterior

Fig. 24-3 Relationship of the breast to the chest wall. Note extension of breast tissue pos­ teriorly into the axilla.

465

The openings of each acinus JOin to forl11 lactiferous ductules that drain the lobules, which in turn join to forl11 1 5 to 20 lactiferous ducts, one for each lobe. Several lactiferous ducts may combine be­ fore emptying directly into the nipple. As a result, there are usually fewer duct open­ ings on the nipple than there are breast ducts and lobes. The indiv idual lobes are incompletely separated from each other by the Cooper's ligaments. The space be­ tween the lobes also contains fatty tissue and additional connective tissue. A layer of fatty tis ue surrounds the gland, except in the area immediately under the areola and nipple (Fig. 24-4 ).

The lymphatic vessels of the breast drain lateral ly into the axillary lymph nodes and medially into the chain of in­ ternal mammary lymph nodes (see Fig. 26-6) . Approx imately 75% of the lymph drainage is toward the axilla, and 25% of the drainage is toward the internal mam­ mary chain. The number of axillary nodes varies from 1 2 to 30 (sometimes more). The axilla is occasional ly radiographed during breast examinations to evaluate the axillary nodes. The internal mammary nodes are situated behind the sternum and manubrium and, if enlarged, are occasion­ ally visible on a lateral chest radiograph.

The radiographer should take into ac­ count breast anatomy and patient body habitus to successfully i mage a much breast ti ssue as possible. Cassette size must be appropriate for the breast being imaged. Larger breasts will not be entirely demonstrated on small i mage receptors. Conversely, smaller breasts should not be imaged on larger cassettes because other body structures will i nterfere with the compression device and thus produce an unacceptable i mage. The natural mobility of the breast is also an important consideration. The lat­ eral and inferior aspects of the breast are mobile, whereas the medial and superior aspects are fixed. The breast should al­ ways be positioned by moving the mobile aspect toward the fixed tissues. Likewise, the radiographer should avoid moving the compression paddle against fixed tissues because this will cause less breast ti ssue to be i maged.

Fat Alveoli

Lobules Cooper's (suspensory) ligament

Nipple

A

�

B Mammary fat

Retromammary fat Lactiferous ducts

Lobe

Inframammary crease

Subcutaneous fat

Interlobular connective tissue

Fig. 24-4 A, Sagittal section through the female breast, illustrating structural anatomy,

B, Breast: anterior view.

466

Tissue Variations The glandular and connective tissues of the brea t are oft tissue-density struc­ tures. The ability to demon trate radio­ graphic detail within the breast depends on the fat within and between the breast lobules and the fat surrounding the breasts. The postpubertal adolescent breast contains primarily den e connec­ tive tissue and casts a relatively homoge­ neous radiographic i mage with little tissue differentiation (Fig. 24-5). The develop­ ment of glandular tissue decrease radio­ graphic contrast. Duri ng pregnancy, sig­ nificant hypertrophy of glands and ducts occurs within the breast . This change causes the breasts to become extremely dense and opaque. After the end of lacta­ tion, considerable involution of glandular and parenchymal tissues usually occurs and these tissues are replaced with in­ creased amounts of fatty tissue. Fat accu­ mulation varies markedly among individ­ uals. This normal fat accumulation significantly increases the natural radio­ graphic contrast within the breasts (Fig. 24-6). The breast of patients with fibro­ cystic parenchymal condition may not undergo this involution (Fig. 24-7).

Fig. 24-5 Craniocaudal projection of normal breast in a 1 9-year-old woman who has never been pregnant. Note the dense glandular tissues with small amounts of fat. In women who do not become pregnant, the breasts may remain dense for many years.

F ig . 24-6 Mediolateral projection of normal breast in a 24-yeor­ old woman who has had two pregnancies. Note decreased vol­ ume of glandular tissue and increased amount of fat.

Fig. 24-7 Croniocoudol projection of breost of 0 42-yeor-old woman with fibrocystic condition. illustrating prominent dilated ducts. 467

The glandular and connective tissue ele­ ments of the breast can regenerate as needed for subsequent pregnancies. After meno­ pause, the glandular and stromal elements undergo gradual atrophy (Fig. 24-8). Ex­ ternal factors such as surgical menopause and ingestion of hormones may inhibit this normal process. From puberty through menopause, marnmotrophic hormones in­ fluence cyclic changes in the breasts. Thus the glandular and connective tissues are in a state of constant change (Fig. 24-9).

Fig. 24-8 Craniocaudal projection of nor­ mal breasts of a 68-year-old woman. Most of the glandular tissue is atrophic. Some glandular tissue remains in the lateral breast posteriorly and in the retroareolar area.

Adolescent

Prepregnancy

Reproductive

Menopausal

Senescent

Fig. 24-9 Diagrammatic profile drawings of breast. illustrating the most likely variation and distribution of radiographic density (shaded areas) related to the normal life cycle from adolescence to senescence. This normal sequence may be altered by external factors such as pregnancy. hormone medications. surgical menopause. and fibrocystic breast condition.

468

EXPOSURE TEC H N IQUE CHART ESSE NTIAL PROJ ECTI ONS MAM MOGRAPHY

AEC

SID

IR

1 00

•

60 cm

1 8 x 24 cm

910

25

100

•

60 cm

1 8 x 24 cm

1 030

5

25

1 00

•

60 cm

1 8 x 24 cm

1 030

5

25

1 00

•

60 cm

1 8 x 24 cm

910

Part

em

kVp·

Mammogram: CC§

5

25

5

tm

mAt

mAs

Dose' (mrad)

·kVp values are for a 1 -phase, high frequency generator. 'Used with the 0.3 mm focal spot. 'Relative doses for comparison use. All doses are skin entrance for average adult at cm indicated. SBucky, 4: 1 Grid. Screen/Film Speed 1 80.

SUMMARY OF ANATOMY* Mammography gland (breast)

Supemcial facia Pectoralis major muscle Serratus anterior muscle Axillary prolongation (axillary tail)

Axillary fossa Nipple Areola Cooper's ligaments Lobes Aci n i Lactiferous ductules

Axillary lymph nodes Internal mammary lymph nodes Glandular tissue Connective tissue Fatty tissue

'See Addendum at the end of the volume for summary of anatomic changes in this edition.

SUMMARY OF PATHO LOGY Condition

Radiographic Finding

Breast Carcinoma

Malignant new growth composed of epithelial cells

Calcification

Deposit of calcium salt in tissue, characteristics may suggest either benign or malignant processes

Cyst

Closed epithelial sac containing fluid or a semisolid substance

Epithelial Hyperplasia

Proliferation of the epithelium of the breast

Fibrosis

Formation of fibrous tissue in the breast

Tumor

New tissue growth where cell proliferation is uncontrolled

Fibroadenoma

Benign tumor of the breast containing fibrous elements

Intraductal Papilloma

A benign, neoplastic papillary growth in a duct

469

RAD IOGRAPHY

Breast Imaging EVOLUTION OF MAMMOGRAPHY SYSTEMS Because the breast is composed of tissues with very similar densities and effective atomic numbers, l ittle difference in atten­ uation is noticed when conventional x-ray equipment and technique are used. There­ fore manufacturers have developed imag­ ing systems that optimally and consis­ tently produce images with high contrast and resolution. Dil igent research and development be­ gan in the 1 960s, and the first dedicated mammography unit was introduced in 1 967 by CGR (France) ( Fig. 24- 1 0) . In the 1 970s, increased awareness of the ele­ vated radiation doses prevalent in mam­ mography served as the catalyst for the rapid progression of screen-film systems. Fi l m manufacturers introduced everal generations of mammography fi l m-screen systems during that decade. Each system showed improvement in contrast and res­ ol ution while minimizing patient dose. In the 1 980s the ACR accreditation pro­ gram established qual ity standards for breast i maging to opti mize mammo­ graph ic equ i pment, processors, and screen-film systems to ensure the produc­ tion of high-quality images. This program was expanded in the 1 990s to include qual ity control and personnel quali fica­ tions and trai ning. The vol untary ACR program has become the model from which MQSA operates, and the ACR has been instrumental in designing the clinical practice guidelines for qual ity mammog­ raphy in the United States. The evolution of mammography has resulted in the im­ plementation of radiographic systems de­ signed specifical ly for breast i maging. MAMMOGRAPHY EQUIPMENT In recent years, equipment manufacturers have produced dedicated mammography units that have high-frequency generators. These generators offer more precise con­ trol of ki lovolt ( peak) (kYp), milliamperes (mA), and exposure time. The linearity and reproducibility of the radiographic ex­ posures using high-frequency generators is uniformly excellent. The greatest benefit of these generators, however, may be the efficient waveform output that produces a higher effective energy x-ray beam per set ki lovolt (peak) and mill iamperes. H igh­ frequency generators are not as bul ky, and they can be installed within the single­ standing mammography unit operating on 470

.1-

single-phase incoming l ine power, thus fa­ cilitating easy installation and creating a less intimidating appearance (Fig. 24- 1 1 ).

METHOD OF EXAM INATION Patients should be dressed in open-front gowns. The breast must be bared because the mammogram will record the slightest wrinkle in any cloth covering. Patients should remove any deodorant and powder

·.�-3

from the axi lla region and breast because these substances will resemble calcifica­ tions on the resultant image. Before the breast is radiographed, a complete hi tory is taken, and a careful physical assessment is performed, noting all biopsy scars, pal­ pable masses, suspicious thickenings, skin abnormalities, and nipple alterations (Fig. 24- 1 2) .

Fig. 24- 1 0 First dedicated mammography system : Senographe by CGR (France).

Fig. 24- 1 1 Senographe DMR by General Electric Company (Milwaukee, Wisc.).

NAME M,R,#

Department of Diagnostic Imaging MAMMOGRAPHY QUESTIONNAIRE

Please answer the following questions:

loday's date:

1 , Vour current age:

Age at menopause:

2, Have you ever had a mammogram? 0 Ves 0 No VVhere?

_ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _

Last mammogram was in

___

(year)

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __

Vour signature will allow the release of prior mammograms should they be needed, Signature:

__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

3, Family history of breast cancer: (please .J) 0 Mother 0 Sister 0 Grandmother DAunt 0 Daughter VVas breast cancer found: 0 Before menopause? 0 After menopause? Since: 4, Are you taking birth control pills or other female hormones? 0 Ves 0 No _ _ _

5, Have you had your breasts examined by a physician or nurse in the past year? 0 Ves 0 No 6, Do you have breast implants? D Ves D No 7, PROBLEMS: A, Have you had prior breast surgery/biopsy?"", D Ves D No If yes, when? VVas your biopsy positive for cancer?""""""", D Ves D No Have you had radiation therapy?" """"" .. " " " D Ves D No

o Right

o Right

o Left

o Right

o Left

B. Do you have breast lumps?"""""""""""""""" D Ves D No

o Right

o Left

D Ves D No

o Right

o Left

D, Do you have any skin or nipple discharge?"", D Ves D No

o Right

o Left

C. Is there pain in the breast?,

o Left

E, If you answered 'yes" to any of the above, please localize area on the diagram below, (The technologist can assist you with this,)

Lump 0 Surgery/scar = '-" Skin change = '#" Mole = ' . " = '

"

, , , ,

-

Right

- -

� � � � - -

- -

- -

-

Left

Fig. 24- 1 2 Sample mammography patient questionnaire, (Courtesy lhe Permanente Medical Group, Inc, Richmond. Calif,)

47 1

Both breasts are routinely radiographed obtaining craniocaudal (CC) and medio­ lateral oblique (MLO) projections. I mage enhancement methods such as spot com­ pression and magnification technique are often useful. it is sometimes necessary to enhance i mages or vary the projections in order to better characterize lesions and cal­ cifications. in symptomatic patients the examination should not be limited to the symptomatic breast. Both breasts should be examined for comparison purposes and because significant lesion may be demon­ strated in a clinically normal breast.

EXAMI NATION PROCEDURES Thi section describes procedures for con­ ducting mammographic examinations us­ ing dedicated systems. The fol low ing steps should be observed: • If possible, examine previous mammo­ graphic studies of patients who are un­ dergoi ng subsequent mammography screening. These images should be evaluated for positioning, compression, and exposure factors to determine if any i mprovement in image qual ity is re­ quired for the current study. Then posi­ tion the breast consistently so that any lesion can be accurately localized and a val id comparison can be made with prior studies. • Explain the procedure simply and com­ pletely to the patient before beginning the examination. It should never be as­ sumed that the patient is fully aware of what the mammographer is about to do-even if the patient has had prior examinations. • In many cases the routine projections will not sufficiently demonstrate all of the breast tissue and additional projec­ tions may be necessary. To al lay patient concerns, the mammographer should explain to the patient before beginning the procedure why additional projec­ tions are sometimes needed and that they do not necessari ly indicate a po­ tential problem. • Before positioning the patient's breast and applying compression, consider the natural mobility of the breast so that pa­ tient discomfort can be minimized. The inferior and lateral portions of the breast are mobile, whereas the superior and medial portions are fixed. Whenever possible, the mobile tissues should be moved toward the fixed tissues.

For each of the two basic breast projec­ tions, ensure that the breast is firmly supported and adjusted so that the nip­ ple is directed forward. • Profile the nipple, if possible. Obtaining an image of the posterior breast tissue should be the primary consideration, and positioning of the nipple in profi le is not always possible. An additional projection to profi le the nipple can be obtained if necessary. Alternatively, a marker may be used to clearly locate the nipple that is not in profile in which case an additional i mage is not needed.

(6)

L MLO

(D) 7 (F) 50° 28 kVp l OO mA 0.5 s 22 1b

• Apply

proper compression to the breast. Compression is an important factor in achieving a high-quality mam­ mogram. The primary objective of compression is to produce uniform breast thickness from the nipple to the most posterior aspect of the breast. Properly applied compression spreads the breast so that the tissue thickness is more evenly distributed over the i mage and better separation of the glandular elements is achieved. A rigid, radiolu­ cent mammography compression pad­ dle faci l itates breast compression. Generally, compression is applied ini­ tially using a hands-free control, and then applied manually during the final phase of compression. The compres­ sion should be taut but not painful. The skin of the properly compressed breast should feel tight when l ightly tapped with the fingertips. When evaluating images, compare the degree of com­ pression with that in previous mammo­ grams and note any variations. If a pa­ tient is unable to tolerate the proper amount of compression, document this information on the patient history form for the radiologist.

(G) III

Fig. 24- 1 3 Correct labeling of mammogra­ phy image: mediolateral oblique projection.

TABLE 24- 1 Labeling codes for mammographic positioning

labeling code

ProJeclion/method

Craniocaudal Mediolateral oblique Implant displaced Spot compression Magnification technique Mediolateral Lateromedial Exaggerated craniocaudal CC for cleavage CC with roll

Tangential Caudocranial MLO for axillary tall Lateromedlal oblique Superolateral to inferomedial oblique From Bassett L et

01.

CC MLO 10

M (used as prefix) ML LM XCCL CV RL (rolled lateral) and RM (rolled medial). (both used as suffix) TAN FB AT LMO SIO

Purpose

Routine Routine Augmented breast Define Define Localize; define Localize; define Localize Define Localize; define Localize; define Localize; define Define Localize; define Define

editors: Quality determinants of mammography, AHCPR Pub No 95-

0632. Rockville. Md. 1 994. U .S. Department of Health and Human Services.

472

• Pl ace

identification markers (Fig. 24- 1 3) according to the following stan­ dard convention: A. Before processing, photographically expose a permanent identification label that includes the facility ' s name and address, the date o f the ex­ amination and the patient's name, ' age, date of birth, and medical num­ ber on the i mage. B. On the cassette near the patient's ax­ il la, place a radiopaque marker indi­ cating both the side examined and the projection used (Table 24- 1 ). C. Before exposure, write the initials of the person performing the exam­ ination on the identification label. D. Label the mammography cassette with an identification n umber (Arabic numeral) . • Mammography film labeling may also include the fol lowi ng: E. A separate date sticker or perfora­ tion F. A label indicating the technical fac­ tors used-ki lovolt ( peak), m i l ­ liampere-seconds, target material, degree of obliquity, density setting, exposure time, compression thick­ ness, etc . G. Identification of the mammographic unit used ( Roman numeral)

• For patients with palpable masses, use

• To evaluate whether or not sufficient

the appropriate radiopaque ( B B or X-spot) marker to identify the location of the mass. A different type of ra­ diopaque marker may be used to iden­ tify skin lesions, scars, or moles. • When using AEC, position the variable­ position detector at the chest wall, the mid-breast, or the anterior breast, de­ pendi ng on breast composition and size. The appropriate location of the AEC detector must be determined for each individual patient. If possible, the detector should be placed under the glandular portion of the breast. • When reviewing i mages, assess con­ trast and density for optimal differenti­ ation of breast tissues. Anatomic mark­ ers should be visible. The projections of one breast should be compared with the same projections of the contralateral breast to evaluate symmetry and consis­ tency of positioning. All i mages should be absent of motion blur, artifacts, and skin folds. Images must be evaluated for potentially suspicious lesions and calcifications which may require image enhancement methods.

breast tissue is demonstrated, the radi­ ographer should measure the depth of the breast from the nipple to the chest wall on both the CC and MLO projec­ tions. The posterior nipple l ine ( PNL) is an i maginary l i ne that is "drawn" obliquely from the nipple to the pec­ toralis muscle, or edge of the i mage, whichever comes first on the MLO pro­ jection. On the CC projection, the PNL is "drawn" from the nipple to the chest wal l , or edge of the image, whichever comes first. The PNL on the CC should be within I cm of depth of the PNL on the MLO projection (Fig. 24- 1 4) . • Between examinations, u s e a disinfec­ tant to clean the cassette tray surface, patient handle grips, and face guard. • For patient comfort, use a heating pad to warm the cassette tray surface. • Remember that mammography is a team effort involving both the patient and the marnmographer. Therefore ac­ knowledge the individual needs of each patient to faci l itate the cooperation and trust necessary to successfully complete the procedure. The nature of the interac­ tion between the radiographer and the patient will more than likely determine whether or not the patient chooses to have subsequent mammograms.

A

B

Fig. 24- 1 4 A, Mediolateral oblique projec­ tion with posterior nipple line drawn, B. Craniocaudal projection with posterior nipple line drawn, The PNL of the cranio­ caudal projection should be within 1 cm of the PNL of the MLO projection,

473

Summary of Mammogra phy Projections

Illustrative summary of mammography projections

Before beginning to learn mammography projections, the student of radiography should carefully study the i l l ustrative summary of mammography projections shown in the box. Familiarity with the dif­ ferent projection names and abbreviations will enhance the student's understanding of the detailed discussions of the projec­ tions presented in thi chapter.

Routine Projections of the Breast Mammography is routinely performed us­ ing the CC and MLO projections.

474

Craniocaudal (CC)·

Mediolateral oblique (MLO)·

Mediolateral (ML)·

Lateromedlal (LM)

'Essential projection.

Illustrative summary of mammography projections-cont'd

Exaggerated craniocaudal (XCCL)'

Craniocaudal for cleavage (CV)

Craniocaudal with roll lateral (RL)

Craniocaudal with roll medial (RM)

Tangential (TAN)

Caudocranial (FB)

Mediolateral oblique for auxilary tail (An

Lateromedial oblique (LMO)

Superlateral to inferomedial oblique (SIO)

475

Breast

.. CRANIOCAUDAl (CC) PROJECTION

Position of part o

Image receptor: 1 8 X 24 cm or

24 X 30 cm

o

Position of patient o

Have the patient stand facing the cas­ sette holder, or seat the patient on an adjustable stool facing the holder.

o

o

o

o

o

o

o

o

While standing on the medial side of the breast to be imaged, elevate the infra­ mammary fold to its maxi mum height. Adjust the height of the cassette to the level of the inferior surface of the pa­ tient's breast. Use both hands to gently pull the breast onto the cassette holder while i nstruct­ i ng the patient to press the thorax against the cassette holder. Keep the breast perpendicular to the chest wal l . Center the breast over the AEC detector, with the nipple in profi le if possible. I mmobil ize the breast with one hand, being careful not to remove this hand until compression begins. Use the other hand to drape the oppo­ site breast over the corner of the cas­ sette. This maneuver improves demon­ stration of the medial tissue. Placing the arm against the patient's back with the hand on the shoulder of the affected side, make certain the shoul­ der is relaxed and in external rotation. Rotate the patient's head away from the affected side.

o

o

o

o

o

o

o

o

o o

Lean the patient toward the machine and rest the patient's head against the face guard. Make certain no other objects obstruct the path of the beam. With the hand on the patient's shoulder, gently slide the skin up over the clavicle. Using the hand that is anchoring the pa­ tient's breast, pull the lateral tissue on the cassette holder without sacrificing medial tissue. Inform the patient that compression of the breast will be used. Bring the com­ pression paddle into contact with the breast while sliding the hand toward the nipple. S lowly apply compression until the breast feels taut. Check the medial and lateral aspects of the breast for adequate compression. Instruct the patient to i ndicate i f the compression becomes uncomfortable. After ful l compression is achieved and checked, move the AEC detector to the appropriate position, and instruct the patient to hold the breath (Fig. 24- 1 5). Make the exposure. Release breast compression immediately.

Fig. 24- 1 5 Craniocaudal projection.

476

Breast

Central ray • Perpendicular to the base of the breast Structures shown

The CC projection demonstrates the cen­ tral, subareolar, and medial fibroglandular breast tissue. The pectoral muscle i s demonstrated in approxi mately 30% o f all CC images. I ' Bassett L, Heinlein R: Good positioning key to imaging of breast, Diagn Imaging 9:69, 1 993.

EVALUATION CRITERIA

•

The fol lowing should be clearly demon­ strated: • The PNL extending posteriorly to edge of image and measuring within I cm of the depth of PNL on MLO projection (Fig. 24- 1 6) • All medial tissue, as shown by the vi­ sualization of medial retroglandul ar fat and the absence of fibroglandu lar tissue extending to posteromedial edge of i mage

• •

•

•

Nipple in profile (if possible) and at midl ine, indicating no exaggeration of positioning For emphasis of medial tissue, exclu­ sion of some lateral tissue Pectoral muscle seen posterior to me­ dial retroglandular fat in about 30% of properly positioned CC images S light medial skin reflection at the cleavage, ensuring adequate inclusion of posterior medial tissue Uniform tissue exposure if compres­ sion is adequate

A

B

Fig. 24-16

A, Bilateral CC projection of a 63-year-old woman, demonstrating proper po­

sitioning. The CC projection should include maximum medial breast tissue with the nip­ ples centered. Left, Breast cancer (arrow). B, Craniocaudal projections with the PNL demonstrated.

477

Breast

.. MEDIOLATERAL OBLIQUE (MLO) PROJECTION Image receptor: 1 8 x 24 cm or

24 X 30 cm Position of patient • Have the patient stand facing the cas­

sette holder, or seat the patient on an adjustable stool facing the holder. Position of part • Determine the degree of obliquity of

the C-arm apparatus by rotating the tube until the long edge of the cassette is parallel to the upper one third of the pectoral muscle of the affected side. The degree of obliquity should be be­ tween 30 and 60 degrees, depending on the patient's body habitus. Adjust the height of the cassette so that the superior border is level with the axil la. • I nstruct the patient to elevate the arm of the affected side over the corner of the cassette holder and to rest the hand on the handgrip adjacent to the cassette. The patient's elbow should be flexed. Place the upper corner of the cassette as high as possible into the patient's axilla between the pectoral and latissimus dorsi muscle so that the cassette is be­ hind the pectoral fold. • Be certain that the patient's affected shoulder is relaxed and leaning slightly anterior. Then placing the flat surface of the hand along the lateral aspect of the breast, gently pull the patient's breast and pectoral muscle anteriorly and medially.

•

Holding the breast between the thumb and fingers, gently l ift it up, out, and away from the chest wall . • Rotate the patient's body toward the cassette whi le asking the patient to bend slightly at the waist. Center the breast with the nipple in pro­ fi le if possible, and hold the breast in position. • Hold the breast up and out by rotati ng the hand so that the base of the thumb and the heel of the hand supports the breast (fingers are pointing away from breast). • Inform the patient that compression of the breast will be used. Continue to hold the breast up and out while sliding the hand toward the nipple as the com­ pression paddle is brought into contact with the breast. Slowly apply compression until the breast feels taut. The corner of the com­ pression paddle should be inferior to the clavicle.

•

•

• Check the superior and inferior aspects

of the breast for adequate compression. • I nstruct the patient to indicate if the

compression becomes uncomfortable. • Pull down on the patient's abdominal •

• •

tissue to open the inframammary fold. I nstruct the patient to hold the opposite breast away from the path of the beam. After ful l compression is achieved, move the AEC detector to the appropri­ ate position, and instruct the patient to hold the breath (Fig. 24- 1 7). Make the exposure. Release breast compression immedi­ ately.

•

•

Fig. 24- 1 7 Mediolateral oblique projection.

478

Breast

EVALUATION CRITERIA

Central ray • Perpendicular to the base of the breast. • The C-ann apparatus is positioned at an

angle determined by the slope of the patient's pectoral muscle (30 to 60 de­ grees) . The actual angle is determined by the patient's body habitus: tall , thin patients require steep angulation, whereas short, stout patients require shallow angulation. Structures shown

The MLO projection demonstrates all of the breast ti sue with emphasis on the lat­ eral aspect and axillary tail .

The fol lowing should be clearly demon­ strated: • PNL measuring within I cm of the depth of PNL on CC projection . ' (While drawi ng the i maginary PNL obliquely fol low i ng orientation of breast tissue toward pectoral muscle, use the fingers to measure its depth from nipple to pectoral muscle or to the edge of the image, whichever comes first [ Fig. 24- 1 8] . ) • Inferior aspect o f the pectoral muscle extending to the PNL or below it if possible

•

• • •

•

•

Pectoral muscle showing anterior con­ vexity to ensure a relaxed shoulder and axilla Nipple in profi le if possible Open inframammary fold Deep and superficial breast tissues well separated when the breast is adequately maneuvered up and out from the chest wall Retroglandular fat well visualized to ensure inclusion of deep fibroglandular breast tissue Uniform tissue exposure if compres­ sion is adequate

' Bassett L: Clinical image evaluation, Radiol Clin North Am 3 3 : 1 027, 1 995.

B

A

Fig. 24- 1 8 A, Mediolateral oblique projections that demonstrate proper positioning. Images should include pectoral muscle to the level of the nipple, posterior breast tissue, and junction of inframammary fold and abdominal skin. B, The PNL is demonstrated.

479

Routine Projections of the Augmented Breast Mammography is clearly the preferred and most reliable technique for breast cancer screening. This technique has an 80% to 90% true-positive rate for detect­ ing cancer in breasts that do not contain i mplants. However, rrullions of women in the United States have undergone aug­ mentation mammoplasty for cosmetic or reconstructive purposes. The true-positive (pathologic-mammographic) breast can­ cer detection rate decreases to approxi­ mately 60% in patients with augmented breasts because i mplants can obscure up to 85% of breast structures, potentially hiding a small cancer that could normally be detected with mammography at an early and curable stage.

480

S uccessful radiography of the aug­ mented breast requires a highly skil1ed mammographer. During the examination precautions must be taken to avoid rupture of the augmentation device. Mammography of the augmented breast presents a chal lenge that cannot be met with the standard two-image exarru­ nation of each breast. An eight-radiograph examination is preferred whenever possi­ ble. The posterior and superior aspects of the augmented breast can be satisfactori ly evaluated using the CC and MLO projec­ tions. However, these four i mages do not adequately demonstrate the surrounding breast parenchyma.

The initial two projections may be combined with the Eklund, or implant dis­ placed, technique. For the Eklund method, the implant is pushed posteriorly against the chest wall so that it is excluded from the im­ age, and the breast tissue surrounding the implant is pul led anteriorly and com­ pressed. This positioning i mproves both compression of breast tissue and visual­ ization of breast structures. The CC and MLO projections are often performed us­ ing the implant displaced technique. Compl ications frequently associated with breast augmentation include fibrosis, increased fibrous tissue surrounding the i mplant, shrinking, hardening, leakage, and pain. Because mammography alone cannot fully demonstrate all complica­ tions, both sonography and MRl are also used for breast examinations in sympto­ matic patients. Whether sonography or MR i maging is used as the adjunct i mag­ ing for followi ng mammography for pa­ tients with suspected i mplant rupture varies from practice to practice.

Sonography of the breast has proved useful in identifying implant leakage when implant rupture is suggested by mammo­ graphic findings and clinical examination and occasionally when leakage is not sus­ pected. It has also successfully identified leakage that has migrated to the axillary lymph nodes. Although sonography is not yet recommended as a screening modality for implant leakage, it has enhanced the mammographic examination. MR1 is currently the most commonly used modality for the diagnostic evaluation of the augmented breast. Although MRl of­ fers several diagnostic advantages, the cost and time-consuming nature of the proce­ dure inhibits its use as a screening modal­ ity. M R 1 has proved useful, however, as a preoperative tool in locating the position of an implant, identifying the contour of the deformity, and confirming rupture and leakage migration patterns. The sensitivity and specificity of MRI have been as high as 94% and 97% respectively. I 'Orel SG: MR imaging of the breast, Radial c/in North Am 38: 899, 2000.

48 1

Augmented Breast

CRAN IOCAUDAl PROJECTION WITH FUll IMPLANT Image receptor: 1 8 x 24 cm or 24 X

Position of part •

•

30 cm • Position of patient • Have the patient stand facing the cas­

sette holder, or seat the patient on an adjustable stool facing the holder.

•

• •

482

Turn the AEC off, and preselect a man­ uaL technique. Follow the same positioning sequence as for the standard CC projection. lnform the patient that compression of the brea t will be used. Bring the com­ pression paddle i nto contact with the breast, and slowly apply enough com­ pression to i mmobilize the breast only. Compression should be minimal. The anterior breast tissue should sti l l feel oft. Select the appropriate exposure factors, and i nstruct the patient to hold the breath. Make the exposure. Release compression immediately.

Augmented Breast

Central ray • Perpendicular to the base of the breast Structures shown

The image should show the entire implant and surrounding posterior breast tissue with suboptimal compression of the anterior fi­ broglandular breast tissue (Fig. 24- 1 9).

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Implant projected over fibroglandular tissue, extending to posterior edge of image • Posterior breast tissue on medial and lateral aspects extending to chest wall

•

•

Nipple in profi le, if possible, and at midli ne, indicating no exaggeration of positioning Nonuniform compression of anterior breast tissue

Fig. 24- 19 Bilateral, four-image craniocaudal and mediolateral oblique examination of the augmented breasts of a 37-year-old woman. Implants have been surgically placed behind the pectoral muscle. Additional radiographs should be obtained using the Eklund technique (implant displaced) to complete the eight-radiograph study (see Fig. 24-2 1 ) . 483

Augmented Breast

CRANIOCAUDAL PROJECTION (CC ID) WITH IMPLANT DISPLACED

Position of part o

Image receptor: 1 8 x 24 cm or 24 X

30 cm Position of patient o

o

o

Have the patient stand facing the cas­ sette holder, or seat the patient on an adjustable stool facing the holder. o

o

o

o

o

o

o o

Fig. 24-20 A, Breast with implant and normal positioning techniques. B, C, and D, Eklund technique of pushing the implant posteriorly against the chest wall and pulling the breast anteriorly and compressing the tissue. (From Eklund GW et al: Improved imaging of the augmented breast. AJR 1 5 1 :469-473.)

484

While standing on the medial side of the breast to be i maged, elevate the in­ framammary fold to its maximum height. Adjust the height of the cassette to the level of the inferior surface of the breast. Standing behind the patient, place both arms around the patient and locate the anterior border of the i mplant by walk­ ing the fingers back from the nipple to­ ward the chest wal l . Once the anterior border o f the i mplant has been located, gently pull the ante­ rior breast tissue forward onto the cas­ sette holder (Fig. 24-20). Use the hands and the edge of the cassette to keep the i mplant displaced posteriorly. Center the breast over the AEC detector with the nipple in profile if possible. Hold the i mplant back against the chest wal l . Slowly apply compression to the anterior skin surface, being careful not to allow the implant to slip under the compression paddle. As compression continues, the implant should be seen bulging behind the compression paddle. Apply compression until the anterior breast tissue is taut. Compared with the full implant view, an additional 2 to 5 cm of compression should be achieved with the implant displaced. Instruct the patient to indicate if the compression becomes uncomfortable. When ful l compression is achieved, move the AEC detector to the appropri­ ate position and i nstruct the patient to hold the breath. Make the exposure. Release breast compression immedi­ ately.

Augmented Breast

Central ray •

Perpendicul ar to the base of the breast

Structures shown

Thjs projection demonstrates the i mplant displaced posteriorly. The anterior and central breast tissue is seen projected free of superi mposition with uniform com­ pression and i mproved tissue differentia­ tion (Fig. 24-2 1 ).

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Breast tissue superior and inferior to the implant pulled forward with the an­ terior breast tissue projected free of the i mplant • Posterior nipple l ine extending posteri­ orly to edge of i mplant measuring within I em of depth of PNL on MLO projection with i mplant displaced

• •

I mplant along posterior edge of i mage, flattened agrunst chest wall I mage sharpness enhanced by increased compression and reduced scatter

Fig. 24-21 Bilateral, four-image with implant displaced (ID) examination of the same pa­ tient as in Fig. 24- 1 9. using the Eklund. or implant displaced. technique. The implants are pushed back for better visualization of surrounding breast tissue.

485

Augmented Breast

MEDIOLATE RAl OBLIQUE PROJECTION (MlO) WITH FUll IMPLANT

Position of part

Structures shown

• Turn the AEC off and preselect a man­

The image shows the entire implant and surrounding posterior breast tissue with suboptimal compression of the anterior fi­ broglandular breast tissue (see Fig. 24- 1 9) .

• Image receptor: 1 8 x 24 cm or 24 X

30 cm

•

Position of patient • Have the patient stand facing the cas­

sette holder, or seat the patient on an adj ustable stool faci ng the holder. •

• •

•

•

ual technique. Follow the same positioning sequence as for the standard M LO projection. Inform the patient that compression of the breast will be used. Continue to hold the breast up and out while sl iding the hand toward the nipple as the com­ pression paddle i s brought i nto contact with the breast. Slowly apply enough compression to im­ mobi lize the breast only. Compression should be minimal, and the anterior breast tissue should still feel soft. Pull down on the patient's abdominal tissue to open the inframammary fold. Select the appropriate exposure factors, and instruct the patient to hold the breath. Make the exposure. Release breast compression immedi­ ately.

Central ray • Perpendicular to the cassette. • The C-ann apparatus is positioned at an

angle determined by the slope of the patient's pectoral muscle (30 to 60 de­ grees). The actual angle is determined by the patient's body habitus: tall , thin pat ients require steep angulation, whereas short, stout patients require shallow angulation.

486

EVALUATION CRITERIA

The following hould be clearly demon­ strated : • I mplant projected over fibroglandular tissue, extending to posterior edge of i mage • Posterior breast tissue on the inferior aspect extending to chest wall • Nipple in profile if possible • Open inframammary fold • Breast adequately maneuvered up and out from chest wal l • Nonuniform compression of anterior breast tissue

Augmented Breast

MEDIOLATERAL OBLIQUE PROJECTION (MLO 1 0) WITH IM PLANT DISPLACED Image receptor: 1 8 x 24 cm or 24 X

• Hold the anterior breast tissue up and

•

30 cm Position of patient • Have the patient stand facing the cas­

sette holder, or seat the patient on an adjustable stool facing the holder. • Position of part • Determine the degree of obliquity of

•

•

•

•

the C-arm apparatus by rotating the tube until the long edge of the cassette is parallel to the upper one third of the pectoral muscle of the affected side. The degree of obl iquity should be be­ tween 30 and 60 degrees, depending on patient's body habitus. Adj ust the height of the cassette so that the superior border is level with the axilla. I nstruct the patient to elevate the arm of the affected ide over the corner of the cassette holder and to rest the hand on the handgrip adjacent to the cassette. The patient's elbow should be flexed. Standing in front of the patient, locate the anterior border of the implant by wal king the fingers back from the pa­ tient's nipple toward the chest wal l . After locating the anterior border o f the i mplant, gently pull the anterior breast tissue forward onto the cassette holder. Use the edge of the cassette and the hands to keep the implant displaced posteriorly. Center the breast over the AEC detector with the nipple in profile if possible.

• • • •

•

•

out so that the base of the thumb and the heel of the hand support the breast (fingers are pointing away from breast). Hold the i mplant back against the chest wal l . Slowly apply compression to the anterior skin surface, being careful not to allow the implant to slip under the compression paddle. As compression continues, the implant should be seen bulging behind the compression paddle. Apply compression until the anterior breast tissue is taut. Compared with the ful l i mplant view, an additional 2 to 5 cm of compression should be achieved with the i mplant displaced. I nstruct the patient to indicate if the compression becomes uncomfortable. Pul l down on the patient's abdominal tissue to open the inframammary fold. I nstruct the patient to hold the opposite breast away from the path of the beam. When full compression is achieved, move the AEC detector to the appropri­ ate position and instruct the patient to hold the breath. Make the exposure. Release breast compression immedi­ ately.

Structures shown

This image hows the implant displaced posteriorly. The anterior and central breast ti ssue is seen projected free of su­ perimposition w ith uniform com pres ion and improved ti ssue differentiation (see Fig. 24-2 1 ). EVALUATION CRITERIA

The following should be clearly demon­ strated: • Breast tissue uperomedial and infero­ lateral to the implant with anterior breast tissue projected free of the implant • Posterior nipple line extending obliquely to edge of implant, measuring within I cm of depth of PNL on CC projection with implant displaced • I mplant projected over fibroglandular tissue extending to posterior edge of image • Posterior breast tissue on inferior aspect of breast extending to chest wall • Nipple in profile if possible • Open inframammary fold • Breast adequately maneuvered up and out from chest wal l • I mage sharpness enhanced by increased compression and reduced scatter

Central ray • Perpendicular to the cassette. • The C-arm apparatus is positioned at an

angle determined by the slope of the pa­ tient's pectoral muscle (30 to 60 de­ grees). The actual angle is detelmined by the patient's body habitus: tall, thin pa­ tients require steep angulation, whereas short, stout patients require shal low angulation.

487

Routine Projections of the Male Breast EPIDEMIOLOGY OF MALE BREAST DISEASE In the United States, approximately 1 300 men develop breast cancer every year, and one third of those men die from the dis­ ease. Although most men who develop breast cancer are 60 years of age and older, juvenile cases have been reported. Based on the medical literature, very few studies are being conducted to ascertain the relevance of breast cancer incidence i n men. Nearly a l l male breast cancers are primary tumors. Because men have signif­ icantly less breast tissue, smaller breast le­ sions are palpable and diagnosed at early stages. Other symptoms of breast disease in men include nipple retraction, crusting, discharge, and ulceration. Gynecomastia, a benign excessive de­ velopment of the male mammary gland, can make malignant breast lesions more el usive to palpation. Gynecomastia occurs in up to 40% of male breast cancer pa­ tients. However, a histologic relationship between gynecomastia and male breast cancer has not been defi nitely established. Because gynecomastia is caused by a hor­ monal i mbalance, it is believed that ab­ normal hormonal function may increase the risk of male breast cancer. Other asso­ ciated risk factors for male breast cancer include increasing age, positive family history, and Klinefelter's syndrome. I Breast cancer treatment options are li mited among male patients. Because men have less breast tissue, lumpectomy is not considered practical . A modified radical mastectomy is usual ly the pre­ ferred surgical procedure. Radiation and systemic therapy is considered when the tumor is located near the chest wall or if i ndicated by lymph node analysis. Like female breast cancer, the prognosis of male breast cancer is directly related to the stage of the disease at diagnosis. An early diagnosis indicates a better chance of survival. Survival rates among male pa­ tients with localized breast carcinomas are positive: 97% survive for 5 years.

MALE MAM MOGRAPHY Male breast anatomy varies significantly from female breast anatomy that the pec­ toral muscle is highly developed in men. The radiographer must take this variance into consideration. The standard CC and MLO projections may be applied with success in many male patients ( Figs. 24-22 through 24-25). However, for men (or women) with l arge pectoral muscles, the radiographer may perform the cau­ docranial (FB ) projection i nstead of the standard CC because it is easier to com­ press the inferior portion of the breast. I n addition, the lateromedial oblique (LMO) projection may replace the standard MLO (see pp. 5 1 0-5 1 1 and 5 1 4-5 1 5).

These supplemental projections allow the radiographer to successfully accom­ modate the patient with prominent pec­ toral muscles. Some facilities also use nar­ rower compression paddles (8 cm in width) for compressing the male breast or the small female breast. I The smaller pad­ dle permits the radiographer to hold the breast in position while applying final compression. A wooden spoon or spatula can also be used to hold the breast in place. 'Eklund GW, Cardenosa G: The art of mammo­ graphic positioning, Radial Clin North Am 30: 2 1 , 1 992.

-4 ;-

Fig. 24-22 Craniocaudal projection of male breast.

' A ppelbaum A et al: Mammographic appearance of male breast disease, Radiographies 1 9:559, 200 I .

Fig. 24-23 Mediolateral oblique projections of male breast. 488

Because most men who undergo mam­ mography present with outward symp­ toms, mammography of the male breast is considered a diagnostic examination. The radiographer should work closely with the radiologist to achieve a thorough demon­ stration of the potential abnormality. I n the male breast, most tumors are located in the subareolar region. Careful attention should be given to adequate compression of this area. Calcifications are rare in male breast cancer cases. When present, they are usu­ ally larger, rounder, and more scattered than the calcifications associated with fe­ male brea t cancer. Spot compression and magnification technique are common im­ age enhancement methods for demon­ strating the morphology of calcifications (see pp. 494-497).

Techniques other than mammography are used to diagnose male breast cancer. FNA B and excisional biopsy of palpable lesions are standard methods of diagnosis. Histologically, most breast cancers in men are ductal, with most being infiltrating ductal carcinoma. Because breast cancer is traditionall y considered a "woman's disease," the radi­ ographer should remain sensitive to the feelings of the male patient by providing not only physical comfort but also psy­ chologic support.

Fig. 24-24 CC projection of a 62-year-old male.

Fig. 24-25 Mediolateral oblique projection of the patient in Fig. 24-24.

489

TABLE 24-2 Supplemental projections/methods and thei r suggested a pplications

Projection/method

Spot compression Magnification (M) Mediolateral (Ml)

lateromedial (lM) Exaggerated CC (XCCl) CC for cleavage (CV) CC with roll (RL RM)

Tangential (TAN)

Caudocranlal (FB)

MlO for axillary tail (AT) lateromedial oblique

Superolateral to Inferomedlal (SIO)

490

Application(s)

Defines lesion or area through focal compression; separates overlying parenchyma Combines with spot compression to demonstrate margins of lesion; delineates microcalcifications localization; demonstrates air-fluid-fat levels; defines lesion located in lateral aspect of breast; comple­ ments MlO projection localization; demonstrates air-fluid-fat levels; defines lesion located in medial aspect of breast Visualizes lesions in deep outer aspect of breast that are not seen on standard CC Visualizes deep medial breast tissue; demonstrates medial lesion in true transverse/axial plane Triangulates lesion seen only on CC projection; defines location of lesion as in either superior or inferior aspect of breast Confirms dermal versus breast calcifications; demon­ strates obscure palpable lump over subcutaneous fat Visualizes superior breast tissue; defines lesion located in superior aspect of breast; replaces standard CC for patients with kyphosis or prominent pectoral muscles Focal compression view of axillary tail Demonstrates medial breast tissue; replaces (lMO) standard MlO for patients with pectus excavatum, prominent pacemakers, prominent pectoral muscles, Hickman catheters, and postoperative open heart surgery Visualizes upper inner quadrant and lower outer quadrant, which are normally superimposed on MlO and lMO projections;

Significant Mammographic Findings The routine projections are not always ad­ equate in completely demonstrati ng a pa­ tient's breast tissue, or a specific area may require clearer deli neation. Supplemental projections complement the routine pro­ jections and have distinct applications (Table 24-2 ) . The mammographer should fully understand the value of each projec­ tion and its abi l ity to demonstrate signifi­ cant findings in the breast. This section provides a brief overview of significant mammographic findi ngs in their most common radiographic presentation and provides suggested correlative supple­ mental projections. The language related to mammographic findings must be appre­ ciated for the mammographer and the ra­ diologist to work collaboratively toward a successful diagnostic examination. The mass is the most common pres­ entation of a potential abnormality in the breast. It is identified on two projections of the affected breast. A mass has a con­ vex shape or an outward contour to its margins. If a suspected mass is only iden­ tified on one projection, the mammogra­ pher must strive to position the breast so that the area in question is demonstrated on at least two projections. For example, if the suspected mass is only seen on the MLO projection in the deep medial aspect of the breast, a CC projection for cleavage may complement the standard CC projec­ tion. Conversely, if the mass is seen in the extreme lateral aspect, an exaggerated CC projection laterally would be the projec­ tion of choice. In a sense the radiographer is collecting evidence to prove whether the mass is real or if it is merely a sum­ mation shadow of superimposed breast parenchyma. Once a mass has been suc­ cessfully identified on two projections, the radiologist describes the mass according to the fol lowing characteristics:

• Shape is a good predictor of the malig­

•

•

•

•

nant or benign nature of the mass. Round, oval, or lobular masses are probably benign. I rregu larly shaped masses are suspicious. Margin characteri stic help predict whether a mass is malignant or benign. WelJ-defined circumscribed masses are probably benign. Microlobulated masses have a 50% chance of being malignant. Mas es with obscured, ill-defined, indis­ tinct margins are suspicious. Spiculated margins may indicate malignancy. Post­ biopsy sCalTing may appear as a spicu­ lated mass, and an accurate patient his­ tory revealing previous breast biopsies can prevent an unnecessary workup (Fig. 24-26). The tissue density of the mass can pre­ dict whether it is malignant or benign. Masses consisting of mostly fat are usually benign, whereas masses con­ sisting of variable fibroglandular tissue could be malignant. Although size cannot predict whether a lesion is malignant or benign, cli nical management is the same regardless of ize. The radiologist may request spot compression i mages to confirm mass characteristic . Magnification projec­ tions may be walTanted only if calcifi­ cations or spiculations are present within the mass. Sonography may be appropriate to determine whether or not the mass is a simple cyst (Fig. 24-27). The malignant or benign nature of a mass cannot be detetmined based on location. Most cancers are detected in the upper outer quadrant of the breast; however, most breast lesions-malignant or be­ nign-are found in that quadrant. Cancer can occur in any region of the breast with a certain degree of probability.

Fig. 24-26 Bilateral craniocaudal projections of a 55-year-Old woman whose left breast has been surgically altered as a result of previous breast cancer. Lumpectomy scar is visi­ ble on left breast (orrow). Surgical scars can mimic characteristics of breast cancer.

Fig. 24-27 Bilateral mediolateral oblique projections of a 27-year-old woman who stopped breast-feeding 2 months before having this mammogram. Dense parenchyma with multinodularity throughout all quadrants is demonstrated bilaterally. A lead marker in the upper quadrant of the right breast marks a palpable mass; sonographic examination proved the mass to be solid.

491

• Interval change may i ncrease the sus­

picion of malignancy. The radiologist carefu l l y compares current i mages with previous ones and notes if the mass is newly apparent, if an i nterval enlargement is present, if the borders have become nodular and/or ill de­ fi ned, or if calcifications have appeared (Fig. 24-28). • Almost all (98%) of the axillary lymph nodes are located in the upper outer quadrant. The nodes are well circum­ scribed, may have a central or periph­ eral area of fat, and can be kidney-bean shaped. If the lymph nodes appear nor­ mal, they are rarely mentioned in the context of an identifiable mass on the radiology report. Examples of benign stellate lesions i ncl ude radial scar, fat necrosis, breast abscess, and scl erosing adenosi s . Examples o f benign circ umscribed masses include fibroadenoma (Fig. 24-29), cyst, i ntramammary ly mph node, hematoma, and galactocele. • A density is seen on only one projec­ tion, is not confirmed three-dimension­ ally, may represent superimposed struc­ tures, and may have scalloped edges and/or concave borders. The radiologist may request spot compression projec­ tions to confirm or deny the presence of a real density. A suspicious density seen on only one projection within the breast is usually a summation shadow of su­ perimposed breast parenchyma and dis­ appears on spot compression. •

Fig. 24-28 Craniocaudal projections of right and left breasts in a 28-year-old woman 4 months postpartum and not breast-feeding. The right breast contains a large mass (ar­ row) palpable on physical examination. The left breast contains two smaller nonpalpable masses (arrows) with microcalcifications. All three lesions were breast cancers.

Fig. 24-29 Craniocaudal projections of bilateral breast masses. Left breast (L) contains an irregular carcinoma that is producing considerable spiculation, nipple retraction (arrow), and skin thickening. Right breast (R) contains fibroadenoma. 492

•

•

Calcifications are often normal meta­ bolic occurrences w ithin the breast and usually benign ( Fig. 24-30). However, approximately 1 5 % to 25% of micro­ calcifications found in asymptomatic women are associated with cancer. These calcifications can have definitive characteristics. Yet, because of size, some microcalcifications are more dif­ ficult to interpret. The most valuable tool for defining microcalcifications is the properly performed magnification projection. Using this image, the radiol­ ogist can ascertain whether the calcifi­ cations are suspicious and warrant any further workup. Benign calcifications may have one or more of the fol lowi ng attributes: mod­ erate size, scattered location, round shape, and, usual ly, bilateral occur­ rence. In addition, they may be eggshell (lucent center), arterial (parallel tracks), crescent, or sedimented ("tea-cup" milk of calcium). Calcifications may also represent a fibroadenoma ("popcorn") and postsurgical scarring (sheets or l arge strands of calcium). The projec­ tion suggested for better defining sedi­ mented milk of calcium is the 90degree lateral projection-Iateromedial (LM) or mediolateral (ML). If possible, the mammographer should select the lateral projection that places the sus­ pected area closest to the cassette. The 90-degree lateral is also used as a trian­ gulation projection before needle local­ ization and for the demonstration of air­ fl uid-fat levels.

Fig. 24-30 Bilateral craniocaudal projections demonstrating multiple, bilateral, benign calcifications.

493

• Suspicious calcifications are small ( oc­

• Other supplemental projections are in­

cUlTing in groups of five or more), lo­ cated within the breast parenchyma ( versus dermal), local ized in distribu­ tion, and branching and linear in shape ( Fig. 24-3 1 ). Dermal or skin calci fica­ tions can mimic suspicious microcalci­ fications within the breast parenchyma. The tangential projection is be t uited for resol ving this discrepancy.

tended to offer alternative methods for tailoring the mammographic procedure to the specific abilities of the patient and the requirements of the interpreting physician. Often, however, the need for additional projections is only determined after careful examination of the standard projections. Therefore, throughout mam­ mographic procedures, the radiographer should con i tently evaluate the images, keeping foremost in mind the optimal demonstration of possible findings. The mammographer may develop the exper­ tise to predict and perform supplemen­ tal projections that demonstrate or rule out suspected breast abnormalities. As with all radiographic procedures, image evaluation is a critical component of high-quality i maging systems. I n doing so, the mammographer becomes an in­ tegral member of the breast imaging team, actively participating in the workup of a symptomatic patient.

I mage E nhancement Methods The spot compression technique and the magn ification technique are desi gned to enhance the i mage of the area under investigation.

A

8

Fig. 24-31 Microcalcifications are an early sign of breast cancer. A, A mass with calcifica­ tions (arrow). B, This type of mass is best visualized with two right-angle projections (arrows). 494

Breast Breast

o

SPOT COMPRESSION TECH NIQUE

o

Make the exposure. Release breast compression immediately. For non palpable masses

Image receptor: 1 8 x 24 cm

o

Position of patient o

Have the patient standing facing the cassette holder, or seat the patient on an adjustable stool faci ng the holder.

Position of part

o

o

In conjunction with magnification technique o

o

Place a firm, radiolucent platform be­ tween the patient's breast and a nongrid cassette device (see pp. 496-497 ). Select the smallest focal spot target size (0. 1 mm or less is preferred). For palpable masses

o

o

o

o

o

o

o

Select the appropriate focal compres­ sion device. Reposition the patient's breast to obtain the projection that best demonstrates the suspected abnormality. Mark the location of the palpable mass with a felt-tip pen. Center the area of interest under the compression device. Inform the patient that compression of the breast will be used. Bring the com­ pression paddle into contact with the breast, and slowly apply compression until the breast feels taut. I nstruct the patient to i ndicate if the compression becomes uncomfortable. When full compression is achieved, move the AEC detector to the appropriate position and i nstruct the patient to hold the breath (Fig. 24-32).

o

o

o

o

o

o

o o

While viewing the routine mammo­ gram, measure the location of the area of interest from a reference point (the nipple), using either a tape measure or the fi ngertips. Select the appropriate focal compres­ sion device. Reposition the patient's breast to obtain the projection from which the measure­ ments were taken. Using the same reference point, trans­ fer the measurements taken from the mammogram onto the patient. Mark the area of i nterest with a felt-tip pen. Center the area of interest under the compression device. Inform the patient that compression of the breast will be used. Bring the com­ pression paddle into contact with the breast, and slowly apply compression until the breast feels taut. Instruct the patient to indicate if the compression becomes uncomfortable. When full compression is achieved, move the AEC detector to the appropri­ ate position, and instruct the patient to hold the breath. Make the exposure. Release breast compression immediately.

Structures shown

The spot compression technique resolves superimposed structures seen on only one projection, better visual izes small lesions located in the extreme posterior breast, separates superi mposed ductal structures in the subareolar region, and improves vi­ sualization in areas of dense tissue through localized compression (Fig. 24-33). EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Area of interest clearly seen within compressed margins • Close coll imation to the area of interest unless contraindicated by radiologist • I mproved recorded detail through the use of close col li mation and a microfo­ cal spot • Uniform tissue exposure if compression is adequate NOTE: Densities caused by the superi mposition of normal breast parenchyma disappear on spot compression i mages.

Central ray 0

Perpendicular to the area of interest

Fig. 24-32 Spot compression used with craniocaudal projection.

Fig. 24-33 Spot compression of suspicious area containing microcalcifications (ar­ row). The lesion was later biopsied and was found to be ductal carcinoma in situ, an early stage of cancer. 495

Breast

MAGNIFICATION TECHN IQUE (M USED AS PREFIX) Image receptor: 1 8 x 24 cm

Place a firm, radiolucent platform be­ tween the patient's breast and a nongrid cassette device. Select the smallest focal spot target size (0. 1 mm or less is preferred). • Select the appropriate compression paddle (regular or spot compression). Reposition the patient's breast to obtain the projection that best demonstrates the suspected abnormality. When ful l compression is achieved, move the AEC detector to the appropri­ ate position and instruct the patient to hold the breath (Fig. 24-34). • Make the exposure. Release breast compression i mmedi­ ately. •

Position of patient •

Have the patient stand facing the cas­ sette holder, or seat the patient on an adjustable stool facing the holder.

Central ray

Position of part •

•

•

Perpendicular to the area of interest

Structures shown

Thi technique magnifies the area of inter­ est with improved detail , facilitating the determination of the characteristics of mi­ crocalcifications (Fig. 24-35) and the mar­ gins (or lack of definitive margins) of us­ pected lesions (Fig. 24-36).

•

•

Fig. 24-34 Radiolucent platform placed between breast and film holder causes the breast image to be enlarged. (Courtesy Lorad Corp.)

496

Fig 24-35 Spot compression used with magnification in mediolat­ eral oblique projection. demonstrating microcalcifications (arrow).

Breast

EVALUATION CRITERIA

The fol lowing should be clearly demon­ trated: • Area of intere t within coll imated and compressed margins • Improved del ineation of number, distri­ bution, and morphology of microcalci­ fications • Enhanced architectural characteristics of focal density or mass • Uniform tissue exposure if compres­ sion is adequate

Supplemental Projections S upplemental projections described in the fol lowing section include the 90-degree mediolateral projection, the craniocaudal projection for cleavage, and others. These projections are designed to delineate areas not visualized or not clearly seen on the more routine projections.

A

B

Fig. 24-36 A, Craniocaudal projection showing possible lesion in right breast (arrow). B, Image with 2 x magnification in the same patient. convincingly demonstrating a lesion with irregular margin (arrowhead).

497

Breast

.. 90- DEGREE MEDIOLATERAl (Ml) PROJECTION

Position of part • Rotate the C-arm assembly 90 degrees

Image receptor: 1 8 x 24 cm or 24

X 30 cm

•

Position of patient •

Have the patient stand facing the cas­ sette holder, or seat the patient on an adjustable stool facing the holder.

•

•

A

B

•

•

•

•

Fig. 24-37 A, Lateral profile of breast. demonstrating inadequate compression and a drooping breast. B, Lateral profile of properly compressed breast. Note how compression has overcome the effect of gravity and how the breast is spread out over a greater area.

• •

• •

• •

Fig. 24-38 Mediolateral projection. 498

with the x-ray tube placed on the me­ dial side of the patient's breast. Have the patient bend slightly forward. Position the superior corner of the cas­ sette high into the axilla, w ith the pa­ tient's elbow flexed and the affected arm resting behind the cassette. Ask the patient to relax the affected shoulder. Pull the breast tissue and pectoral mus­ cle superiorly and anteriorly, ensuring that the lateral rib margin is pressed fi rmly against the edge of the cassette. Rotate the patient sl ightly laterally to help bring the medial tissue forward. Gently pull the medial breast tissue for­ ward from the sternum, and position the nipple in profile. Hold the patient's breast up and out by rotating the hand so that the base of the thumb and the heel of the hand support the breast. Inform the patient that compression of the breast will be used. Continue to hold the patient's breast up and out while sliding the hand towards the nipple as the compression paddle is brought into contact with the breast. Do not allow the breast to droop (Fig. 24-37). Slowly apply compression until the breast feels taut. I nstruct the patient to indicate if com­ pression becomes uncomfortable. Ask the patient to hold the opposite breast away from the path of the beam. When full compression is achieved, move the AEC detector to the appropri­ ate position, and instruct the patient to hold the breath (Fig. 24-38). Make the exposure. Release breast compression immediately.

Breast

Central ray •

Perpendicular to the base of the breast

Structures shown

This projection demonstrates lesions on the lateral aspect of the breast in the supe­ rior or inferior aspects. It resolves super­ impo ed structures seen on the MLO pro­ jection, localizes a lesion seen on one (or both) of the i nitial projection(s), and demonstrate air-fluid and fat-fluid levels in breast structures ( i .e., milk of calcium, galactoceles) and in pneumocystography.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • N ipple in profile • Open inframammary fold • Deep and superficial breast tissues well separated when breast is adequately maneuvered up and out from chest wall (Figs. 24-39 and 24-40) • Retroglandular fat well visualized to ensure inclusion of deep fibroglandular breast tissue • Uniform tissue exposure if compres­ sion is adequate

Fig. 24-39 Mediolateral projection is often used as a preliminary projection in a breast localization procedure. The arrow denotes the lesion.

Fig. 24-40 Mediolateral projection of a normal breast of a 24-year-old woman.

499

Breast

90-DEGREE LATEROMEDIAl (lM) PROJECTION

Position of part o

Image receptor: 1 8 X 24 cm or 24 X

30 cm Position of patient o

Have the patient stand facing the cas­ sette holder, or seat the patient on an adj ustable stool facing the holder.

o

o

o

o

o

o

o

Rotate the C-arm assembly 90 degrees with the x-ray tube pl aced on the lateral side of the patient's breast. Position the superior comer of the cas­ sette at the level of the jugular notch. Have the patient flex the neck sl ightly forward. Have the patient relax the affected shoulder, flex the elbow, and rest the af­ fected arm over the top of the cassette. Pull the breast tissue and pectoral mus­ cle superiorly and anteriorly, ensuring that the patient's sternum is pressed firmly against the edge of the cassette. Rotate the patient slightly medially to help bring the lateral tissue forward. Position the nipple in profile.

o

o

o

o o

Hold the patient's breast up and out. Do not let it droop. I nform the patient that compression of the breast will be used. Bring the com­ pression paddle past the lati simus dorsi muscle and into contact with the breast. Then slowly apply compression while sliding the hand out toward the nipple until the patient's breast feels taut. I nstruct the patient to i ndicate if the compression becomes uncomfortable. When full compression is achieved, move the ABC detector to the appropri­ ate position, and i nstruct the patient to hold the breath (Fig. 24-4 1 ). Make the exposure. Release breast compression immediately.

Fig. 24-41 Lateromedial projection.

500

Breast

Central ray • Perpendicular to the base of the breast Structures shown

This projection demonstrates lesions on the medial aspect of the breast in the su­ perior or inferior aspects (Fig. 24-42). It resolves superimposed structures seen on the MLO projection, localizes a lesion een on one (or both) of the initial projec­ tion(s), and demonstrates air-fluid and fat­ fluid levels in breast structures (i.e., milk of calcium, galactoceles) and in pneumo­ cystography.

EVALUATION CRITERIA

The following should be clearly demon­ strated: • N ipple in profi le • Open inframammary fold • Deep and superficial breast tissues well separated when breast is adequately maneuvered up and out from chest wall • Retroglandular fat well visualized to ensure inclusion of deep fibroglandular breast tissue • Uniform tissue exposure if compres­ sion is adequate

Fig. 24-42 Loteromediol projection.

50 1

Breast

'" EXAGGERATED CRANIOCAUDAL (XCCL) PROJECTION

Position of part o

o

Image receptor: 1 8 X 24 cm or 24 X 30 cm

o

Position of patient o

Have the patient stand facing the cas­ sette holder, or seat the patient on an adjustable stool facing the holder.

o

o

o

o

o

o

o

o

o

Fig. 24-43 Exaggerated CC projection.

o o

Fig. 24-44 Superior profile illustrating how placement of the fiat edge of the cassette against the curved chest wall excludes a portion of the breast tissue (shaded area). Dashed line indicated placement of cassette for exaggerated position.

502

Elevate the inframammary fold to its maximum height. Adjust the height of the cassette ac­ cordingly. Use both hands to gently pull the breast onto the cassette holder while i nstruct­ i ng the patient to press the thorax against the cassette tray. Slightly rotate the patient medially to place the l ateral aspect of the breast on the cassette. Place an aml against the patient's back with the hand on the shoulder of the af­ fected side, making certai n that the shoulder i s relaxed in external rotation . Slightly rotate the patient 's head away from the affected side. Have the patient lean toward the ma­ chine and rest the head against the face guard. Rotate the C-arm assembly mediolater­ ally 5 degrees to eliminate overlapping of the humeral head. Inform the patient that compression of the brea t will be u ed. Smoothen and flatten the breast tis ue toward the nip­ ple while bringing the compression paddle into contact with the breast. S lowly apply compres ion until the breast feels taut. I nstruct the patient to indicate if the compression become uncomfortable. When fu l l compression is achieved, move the AEC detector to the appropri­ ate position, and instruct the patient to hold the breath (Figs. 24-43 and 24-44) . Make the exposure. Release breast compression immedjately.

Breast

Central ray • Angled 5 degree mediolaterally to the

base of the breast Structures shown

Thi s projection demonstrates a superoin­ ferior projection of the lateral fibroglan­ dular breast ti ssue and posterior aspect of the pectoral muscle. It also demonstrates a agittal orientation of a lateral lesion lo­ cated in the axillary tail of the breast.

EVALUATION CRITERIA

The following should be clearly demon­ strated : • Retroglandular fat well visualized to ensure i nclusion of deep fibroglandular breast tissue on lateral aspect of breast and lower axillary region • Pectoral muscle visualized over lateral chest wall (Fig. 24-45) • Humeral head projected clear of image with use of a 5-degree ML angle • Uniform tissue exposure if compres­ sion is adequate

B

A

Fig. 24-45 A, Craniocaudal projection of left breast. B, Exaggerated craniocaudal pro­ jection. This projection is exaggerated laterally to demonstrate axillary tail (arrow). Note also visualization of the pectoral muscle.

503

Breast

CRAN IOCAUDAL PROJECTION FOR CLEAVAGE (CV)

Position of part • Turn the AEC off, and preselect a man­

Image receptor: 1 8 x 24 cm or 24 X

30 cm Position of patient • Have the patient stand faci ng the cas­

•

sette holder, or seat the patient on an adj ustable stool facing the holder. • •

• • •

•

•

•

\ Fig. 24-46 Craniocaudal projection for cleavage. Note that cleavage is Slightly off-center so AEC is under breast tissue.

504

• •

• •

ual technique. The radiographer may use AEC only if enough breast tissue is positioned over the AEC detector. The cleavage may be intentionally offset for this purpose. Determine the proper height of the cas­ sette by elevating the inframammary fold to its maximum height. Adj ust the height of the cassette ac­ cordingly. Standing behind the patient, use both hands to gently l i ft and pul l both breasts forward onto the cassette holder while i nstructing the patient to press the thorax against the cassette tray. Pull as much medial breast tissue as possible onto the cassette holder. Slightly rotate the patient's head away from the affected side. Have the patient lean toward the ma­ chine and rest the head against the face guard. Ask the patient to hold the grip bar with both hands to keep in position on the cassette. Place one hand at the level of the pa­ tient's jugular notch, and then slide the hand down the patient's chest while pulling down as much deep medial tis­ sue as possible. I nform the patient that compression of the breast will be used. Bring the com­ pression paddle into contact with the breasts, and slowly apply compression until the breast feels taut. I nstruct the patient to indicate when the compression becomes uncomfortable. When ful l compression is achieved, move the AEC detector to the appropri­ ate position if AEC is used, and in­ struct the patient to hold the breath (Fig. 24-46). Make the exposure. Release breast compression inmlediately.

Breast

Central ray • Perpendicular to either the area of in­

terest or the centered cleavage Structures shown

This projection demonstrates lesions lo­ cated in the deep posteromedial aspect of the breast.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Breast of interest over the central por­ tion of the cassette (over the ABC de­ tector if possible) with cleavage slightly off-centered or with cleavage centered to the cassette and manual technique selected (Fig. 24-47) • Deep medial tissue of affected breast • All medial tissue included, as shown by the visualjzation of medjal retroglandu­ lar fat and the absence of any fibroglan­ dular tissue extending to posteromedial edge of imaged breasts • Uniform tissue exposure if compres­ sion is adequate (Retroareolar regions may not be adequately compressed be­ cause of emphasis on the deep medjal tissue.)

Fig. 24-47 Craniocaudal projection for cleavage demonstrating benign calcifications located in deep medial tissue (arrow). With a centered cleavage, manual technique should be selected.

505

Breast

CRAN IOCAUDAL PROJECTION WITH ROLL LATERAL OR ROLL ME DIAL (RL OR RM USED AS SUFFIX) Image receptor: 1 8 x 24 cm or 24 X

Position of part o

o

30 cm Position of patient o

Have the patient stand facing the cas­ sette holder, or seat the patient on an adjustable stool faci ng the holder.

o

A

B

c

Source L CC

li @

I

t

o

L CC RM --

� •

---P

0.

Fig. 24-48 A, Craniocaudal projection demonstrating a lesion that may represent super­ imposition of two structures. If spot compression fails to resolve these structures, a cranio­ caudal projection with the roll position may be performed. B, Anterior view of craniocau­ dal projection, with arrows indicating rolling of superior and inferior breast surfaces in opposite directions to separate superimposed structures. C, Craniocaudal projection with roll (RM), demonstrating resolution of two lesions. The arrow indicates the direction of the roll of the superior surface of the breast.

o

o

o

o

o o

Fig. 24-49 Craniocaudal projection with lateral and medial roll, respectively.

506

Reposition the patient's breast in the projection that best demonstrates the suspected superi mpos i tion ( u sual ly the CC projection ) . Place the hands o n opposite surfaces of the patient's breast (superior/inferior), and roll the surfaces in opposite direc­ tions. The direction of the roll is not im­ portant as long as the mammographer rol ls the superior surface in one direc­ tion and the inferior surface in the other direction. In a sense the mammogra­ pher is very gently rotating the breast approximately 1 0 to 1 5 degrees (Fig. 24-48). Place the patient's breast onto the cas­ sette surface with the lower hand, while holding the rolled position with the up­ per hand. Note the direction of the superior sur­ face roll (lateral or medial), and label the i mage accordi ngly. For example, if the superior aspect of the breast is rolled medially, the image should be la­ beled RM. I nform the patient that compression of the breast will be used. Bring the com­ pression paddle into contact with the breast, and sl ide the hand out while rolling the breast tissue. Slowly apply compression until the breast feels taut. I nstruct the patient to indicate if the compression becomes uncomfortable. When ful l compression i s achieved, move the AEC detector to the appropri­ ate position and instruct the patient to hold the breath ( Fig. 24-49). Make the exposure. Release breast compression immediately.

Breast

EVALUATION CRITERIA

Central ray • •

Perpendicular to the base of the breast. Alternatively, the standard CC projec­ tion may be performed with the C-arm assembly rotated 1 0 to 1 5 degrees ei­ ther mediolateral l y or lateromedially to eliminate uperimposition of brea t tissue.

Structures shown

Thi position demonstrates separation of superimposed breast tissues (also known as summation. shadow), particularly those seen only on the CC projection. The po i­ tion al 0 helps to determine if a Ie ion is located in the superior or i nferior aspect of the breast (Fig. 24-50).

The fol lowing should be clearly demon­ stI'ated: • Suspected superimposition adequately resolved • Suspected lesion in either superior or inferior aspect of breast • PNL extending posteriorly to edge of i mage, measuring within I cm of the depth of PNL on MLO projection • All medial tissue included, as shown by the visual ization of medial retroglandu­ lar fat and the absence of fibroglandular tissue extending to posteromedial edge of image • ipple i n profi le, if possible, and at midline, indicating no exaggeration of positioning • Some lateral tissue po ibly excl uded to emphasize medial tissue visualized • Sl ight medial skin reflection at cleav­ age, ensuring that posterior medial tis­ sue is adequately included • Uniform tissue exposure if compres­ sion is adequate

Fig. 24-50 Craniocaudal projection with roil lateral (RL).

507

Breast

TANGENTIAL (TAN) PROJECTION

Position of part For a palpable mass

Image receptor: 1 8 x 24 cm Position of patient o

Have the patient stand faci ng the cas­ sette holder, or seat the patient on an adjustable stool faci ng the holder.

Select either a standard or spot com­ pression paddle. Locate the area of interest by palpating the patient's breast. Place a radiopaque marker or BB on the mass. Rotate the patient's breast tissue and/or rotate the C-arm apparatus until the central ray is directed tangential to the breast at the point identified by the B B marker (the "shadow" of the B B will be projected onto the cassette surface) . U s i n g t h e appropriate compression paddle (regular or spot compression), compress the breast and skin area while ensuring that enough breast tissue cov­ ers the AEC detector area. A reduction in density may be necessary to avoid overexposing the area of interest. Slowly apply compression until the breast feels taut. Instruct the patient to indicate if the compression becomes uncomfortable. When full compression is achieved, move the AEC detector to the appropri­ ate position, and instruct the patient to hold the breath (Fig. 24-5 1 ). Make the exposure. Release breast compression immedi­ ately. For skin localization or nonpalpable dermal calcifications, two projections are necessary: ( 1 ) a localization projection, which depends on the area of interest); and (2) a tangential projection.

Localization projection o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o o

From the routine CC and MLO projec­ tions, determine the quadrant in which the area of interest is located. Determine which projection will best localize the area of interest-the CC or 90-degree lateral projection. Turn off the automatic compression re­ lease, and inform the patient that com­ pression will be continued while the first image is processed. Using a localization compression pad­ dle, position the C-arm and breast so that the paddle opening is positioned over the quadrant of interest. Slowly apply compression until the breast feels taut. I nstruct the patient to indicate if the compression becomes uncomfortable. When full compression is achieved, move the AEC detector to the appropri­ ate position, and instruct the patient to hold the breath. Make the exposure. Do not release compression. Keep the breast compressed while the initial im­ age is processed.

o o

Fig. 24-51 Tangential projection.

508

Breast

Tangential projection o

o

o

o

o

o

o

o

o o

Check the initial i mage, and locate the area of interest using the alphanumeric identifiers. With the patient's breast stil l under compression, locate the corresponding area on the breast and place a ra­ diopaque marker or B B over the area. Release breast compression, and re­ place the local ization compression pad­ dle with a regular or spot compression paddle. Rotate the breast tissue and/or rotate the C-arm apparatus until the central ray i directed tangential to the breast at the point identified by the B B marker (the "shadow" of the BB will be pro­ jected onto the cassette surface). Compress the area while ensuring that enough breast tissue covers the AEC detector area. A reduction in density may be necessary to avoid overexpo­ sure of the area of interest. Slowly apply compression unti l the breast feels taut. In truct the patient to indicate if the compression becomes uncomfortable. When full compression is achieved, move the AEC detector to the appropri­ ate po ition, and instruct the patient to hold the breath. Make the exposure. Release breast compression i mmediately.

EVALUATION CRITERIA

Central ray o

Perpendicular to the area of interest

Structures shown

This projection demonstrate superficial lesions close to the skin surface with min­ imal parenchymal overlapping. I t also shows skin calcifications or palpable le­ sions projected over subcutaneous fat (Fig. 24-52).

The following should be clearly demon­ strated: • Palpable lesion visual ized over subcu­ taneou fat • Tangential radiopaque marker or B B marker accurately correlated with pal­ pable lesion • M i nimal overlapping of adjacent parenchyma • Calci fication in parenchyma or skin • Uniform tissue exposure if compres­ sion is adequate

A

B

Fig. 24-52 A. A 90° mediolateral projection performed with a localization compression paddle to determine the location of suspicious microcalifications. Note that the mammo­ grapher placed a wire on the surface of the breast encircling the area In question. 8. A tangential projection with spot compression of the localized area demonstrating benign dermal calcifications.

(From Wentz G:

Mammography for radiologic technologists,

ed 2, New York. 1 997, McGraw-HilI.) 509

Breast

CAUDOCRANIAL (FB) PROJECTION Image receptor: 1 8 x 24 cm or 24 X 30 cm Position of patient •

Have the patient stand facing the cas­ sette holder.

Position of part

Rotate the C-arm apparatus 1 80 de­ grees from the rotation used for a rou­ tine CC projection. • Standing on the medial side of the breast to be i maged, elevate the infra­ mammary fold to its maximum height. Adj ust the height of the cassette 0 that it is in contact with the superior breast tissue. Lean the patient slightly forward while gently pull ing the elevated breast out and perpendicular to the chest wal l . Hold the breast in position. Have the patient rest the affected arm over the top of the cassette holder. I nform the patient that compression of the brea t will be used. Bring the com­ pres ion paddle from below into con­ tact with the patient' breast while sl id­ ing the hand toward the nipple. Slowly apply compression until the breast feels taut. Instruct the patient to indicate if the compression becomes uncomfortable. To ensure that the patient's abdomen is not uperimposed over the path of the beam, have the patient pull in the ab­ domen or move the hips back sl ightly. When ful l compression is achieved, move the AEC detector to the appropri­ ate position, and instruct the patient to hold the breath (Fig. 24-53 ) . • Make the exposure. Release breast compression immediately.

•

•

•

•

•

•

•

•

•

•

Fig. 24-53 Caudocranial projection.

510

Breast

Central ray • Perpendicular to the base of the breast Structures shown

This projection shows an inferosuperior projection of the breast for the improved visualization of Ie ions located in the su­ perior a pect as a result of reduced O I D . The caudocranial projection also facili­ tates a shorter route for needle-wire inser­ tion to localize an inferior lesion (Figs. 24-54 and 24-55 ) . The projection is also used as a replacement for the standard CC in patients with prominent pectoral mus­ cles or kyphosi .

Fig. 24-54 Caudocranial projection per­ formed in a 57-yeor-old woman to facili­ tate the shortest route for localizing a lesion identified in the inferior aspect of the breast (arrow).

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • S uperior breast tissue/lesions clearly visualized • For needle localization i mages, inferior lesion visual ized within special ized fenestrated compression plate • Patient's abdomen projected clear of the i mage • Inclusion of fixed posterior tissue of the superior aspect of the breast • PN L extending posteriorly to edge of image, measuring within 1 cm of depth of PNL on MLO projection

•

•

• •

•

All medial tissue included a hown by the visualization of medial retroglandu­ lar fat and the absence of fibroglandular tissue extending to posteromedial edge of i mage Nipple in profile, if possible, and at midline, indicating no exaggeration of positioning Some lateral tissue possibly excluded to emphasize medial tis ue Sl ight medial kin reflection at the cleavage, ensuring that posterior medial tissue is adequately included Uniform tissue exposure if compres­ sion is adequate

Fig. 24-55 Orthogonal 90-degree medio­ lateral projection of the patient as in Fig. 24-63, demonstrating successful placement of the needle-wire system within the lesion (arrow). The lesion was found to be a 9-mm infiltrating ductal carcinoma.

51 1

Breast

MEDIOLATERAL OBLIQUE PROJECTION FOR AXI LLARY TAIL (AT)

Position of part • Determine the degree of obliquity of

Image receptor: 1 8 x 24 cm or 24 X 30 cm Position of patient

•

Have the patient stand faci ng the cassette holder, or seat the patient on an adjustable stool facing the holder.

•

•

•

•

•

• •

• • Fig. 24-56 Mediolateral oblique projection for AT.

51 2

the C-arm apparatus by rotating the tube until the long edge of the cas ette is paral lel with the axi llary tail of the affected side. The degree of obliquity varies between 1 0 and 45 degrees. Adjust the height of the cassette so that the superior border is just under the axi l la. Instruct the patient to elevate the arm of the affected side over the corner of the cassette and to rest the hand on the handgrip adjacent to the cassette holder. The patient's elbow should be flexed. Have the patient relax the affected shoulder and lean it sl ightly anterior. Using the flat surface of the hand, gen­ tly pull the tail of the breast anteriorly and mediaJly onto the cassette holder. Ask the patient to turn the head away from the side being exami ned and to rest the head against the face guard. I nform the patient that compression of the breast will be used. Continue to hold the breast in position while sliding the hand toward the nipple as the com­ pres ion paddle is brought into contact with the axillary tail (Fig. 24-56). S lowly apply compression until the breast feels taut. The corner of the com­ pression paddle hould be inferior to the clavicle. I nstruct the patient to indicate if the compression becomes uncomfortable. When ful l compression is achieved, move the AEC detector to the appro­ priate position, and instruct the patient to hold the breath. It may be necessary to increase exposure factors if com­ pression is not as taut as in the routine projections. Make the exposure. Release breast compression immediately.

Breast

Central ray • •

Perpendicular to the cassette. The angle of the C-arrn apparatus is de­ termined by the slope of the patient's axillary tail.

Structures shown

This projection demonstrates the axillary tail of the breast with emphasis on its lat­ eral as peel.

EVALUATION CRITERIA

The fol lowing should be clearly demon­ strated: • Axillary tai l with inclusion of axillary lymph nodes under focal compression (Fig. 24-57) • Uniform tis ue exposure if compres­ sion is adequate • Slight skin reflection of affected arm on superior border of image

Fig. 24-57 Mediolateral oblique projection for AT of a 68-year-old woman. demonstrating ill-defined stellate mass measuring 8 mm (arrow). Biopsy confirmed the lesion to be an infiltrating ductal carcinoma.

513

Breast

LATE ROMEDIAL OBLIQUE (LMO) PROJECTION Image receptor: 1 8 x 24 cm or 24 X 30 cm Position of patient • Have the patient stand facing the cas­

sette holder, or seat the patient on an adjustable tool facing the holder.

Position of part

• Scoop breast tissue up with the hand,

• Determine the degree of obl iquity of

the C-arm apparatus by rotating the as­ sembly until the long edge of the cas­ sette is parallel with the upper one third of the pectoral muscle of the affected side. The central ray enters the inferior aspect of the breast from the lateral side. The degree of obl iquity should be between 30 and 60 degrees, depending on the body habitus of the patient. • Adjust the height of the cassette so that its superior border is level with the jugular notch. • Ask the patient to place the opposite hand on the C-arm. The patient's elbow should be flexed. Lean the patient toward the C-arm ap­ paratus, and press the sternum against the edge of the cassette, which will be slightly off center toward the opposite breast. • Have the patient relax the affected shoul­ der and lean it slightly anterior. Gently pull the patient's breast and pectoral muscle anteriorly and medially with the flat surface of the hand positioned along the lateral aspect of the breast. •

•

•

• • • • •

• •

gently grasping the breast between fi n­ gers and thumb. Center the breast with the nipple in pro­ fi le, if possible, and hold the breast in position. Inform the patient that compression of the breast will be used. Continue to hold the patient's breast up and out whi le sliding the hand toward the nip­ ple a the compression padd le i s brought into contact with the lower outer quadrant of the breast. Slowly apply compression until the breast feels taut. I nstruct the patient to indicate if the compression becomes uncomfortable. Pull down on the patient's abdominal tissue to open the inframammary fold. Ask the patient to rest the affected el­ bow on the top edge of the cassette. When full compression is achieved, move the AEC detector to the appropri­ ate position, and instruct the patient to hold the breath (Fig. 24-58). Make the exposure. Release brea t compression immediately.

Fig. 24-58 Lateromedial oblique projection.

514

Breast

EVALUATION CRITERIA

Central ray • Perpendicular to the cassette. • The C-arm apparatus is positioned at an

angle determined by the slope of the patient' pectoral muscle (30 to 60 de­ grees). The actual angle is determined by the patient's body habitus: tall, trun pa­ tients require steep angulation, whereas short, stout patients require shal low angulation. Structures shown

This projection demonstrates a true re­ verse projection of the routine MLO pro­ jection and is typically performed to bet­ ter demon trate the medial breast ti sue. It is also performed if the routine MLO can­ not be completed because of one or more of the following conditions: pectus exca­ vatum, post open-heart surgery, prominent pacemaker, males or females with promi­ nent pectoralis muscles, or port-a-cath ( H ickman catheters) .

The following should be clearly demon­ strated: • Medial breast tissue clearly vi sualized (Fig. 24-59) • PNL measuring within 1 cm of the depth of the PNL on the CC projection (While drawi ng the PNL obliquely, fol­ lowing the orientation of the breast tis­ sue toward the pectoral muscle, mea­ sure its depth from nipple to pectoral muscle or to the edge of the image, whichever comes first. ) • Inferior aspect of the pectoral muscle extending to nipple line or below it if possible • Pectoral muscle with anterior convexity to ensure a relaxed shoulder and axilla • Nipple in profi le if possible • Open inframammary fold • Deep and superficial breast tissues well separated when brea t is adequately maneuvered up and out from chest wall • Retroglandular fat well visual ized to ensure i nclusion of deep fibroglandular breast tissue • Uniform tissue exposure if compres­ sion is adequate

Fig. 24-59 Lateromedial oblique projection. (From Svane G: 1 993. Mosby.)

Screening mammography, St

Louis. 515

Breast

SUPEROLATERAL TO INFE ROMEDIAL OBLIQUE (510) PROJ ECTION

Position of part

Image receptor: 1 8 x 24 cm or 24 X 30 cm • Position of patient • Have the patient tand facing the cas­

sette holder, or seat the patient on an adjustable stool facing the holder.

• I nform the patient that compression of

• Rotate the C-ann apparatus so that the

•

•

•

•

central ray is directed at an angle to en­ ter the superior and lateral aspect of the affected breast. The lower inner quad­ rant will be adjacent to the cassette Adjust the degree of C-ann obliquity according to the body habitus of the patient. Adj ust the height of the cassette to po­ sition the patient's breast over the cen­ ter of the cassette. I nstruct the patient to rest the hand of the affected side on the handgrip adja­ cent to the cassette holder. The patient's elbow should be flexed. Place the upper corner of the cassette along the sternal edge adjacent to the up­ per inner aspect of the patient's breast. With the patient leaning slightly for­ ward, gently pull as much medial tissue as pos ible away from the sternal edge while holding the breast up and out. The breast should not droop.

•

•

• •

•

•

• •

the breast will be used. Continue to hold the breast up and out. Bring the compression paddle under the affected arm and into contact with the patient's breast while sliding the hand toward the patient's nipple. S lowly apply compression until the breast feels taut. The upper corner of the compression paddle should be in the axi l la. I nstruct the patient to indicate if the compression becomes uncomfortable. When ful l compression is achieved, help the patient bring the arm up and over with the flexed elbow resting on top of the cassette. Gently pull down on the patient's ab­ dominal tissue to smooth out any skin folds. Move the ABC detector to the appropri­ ate position, and i nstruct the patient to hold the breath (Fig. 24-60). Make the exposure. Release breast compression immediately.

Fig. 24-60 Superolateral to inferomedial oblique projection.

516

Breast

Central ray • Perpenclicul ar to the cassette. • The C-arm apparatus is positioned at an

angle determined by the patient's body habitus. Structures shown

This projection demonstrates the upper in­ ner and lower outer quadrants of the breast free of superimposition. In addi­ tion, lesions located in the lower inner as­ pect of the breast are shown with better recorded detai l . This projection may also be used to replace the mediolateral oblique with implant displaced ( MLO-ID) projection in patients with encapsulated implants (Fig. 24-6 1 ).

EVALUATION CRITERIA

The following should be clearly demon­ strated: • Upper inner and lower outer quadrants free of superimposition (These quad­ rants are superimposed on both the MLO and the LMO projections.) • Lower inner aspect of breast visual ized with greater detail • Nipple in profile if possible • Deep and superficial breast tissues well separated when breast is adequately maneuvered up and out from chest wall • Retroglandular fat well visualized to ensure inclusion of deep fibroglandular breast tissue • Uniform tissue exposure if compres­ sion is adequate

Fig. 24-61 Superolateral to inferomedial oblique projection.

51 7

Localization of Nonpalpable Lesions When mammography identifies a nonpal­ pable lesion that warrants urgical biopsy, the abnormality must be accurately lo­ cated so that the smallest amount of breast tissue is removed for microscopic evalua­ tion, thereby minimizing trauma to the breast. This technique conserves the max­ imum amount of normal breast tissue un­ less extensive surgery is indicated. Nonpalpable breast lesions can be local­ ized using three techniques: ( I ) needle­ wire localization, ( 2 ) FNAB, and ( 3 ) l arge­ core needle biopsy (LCN B). Needle-wire local ization uses a needle that contains a hooked guide wire. FNAB uses a hollow 22-gauge needle to extract tissue cel ls from a suspicious lesion. FNAB can po­ tentially decrea e the need for surgical ex­ cisional biopsy by identifying benign le­ sions and by diagnosing malignant lesions that will require extensive surgery rather than excisional biopsy. LCN B obtains small samples of breast tissue by means of a 1 4-gauge needle with a groove adjacent to the tip of the needle. An I I -gauge probe can be used to obtain larger tissue samples. Because larger tissue samples are obtained with LeNB , clinical support exists for using this technique instead of surgical excisional biopsy. LeNB may be used with sonographic guidance. In this case, a l i near array transducer of 7.5 M Hz or higher should be used. Free-hand posi­ tioning of the needle is usual ly preferred with this modality. LeNB is also used i n conjunction with stereotactic localization guidance systems (discussed later in this chapter). The method used depends on the preference of the radiologist and the sur­ geon and is typically determined by the degree of experience and success with each respective method. With all three methods, i mages are used to triangulate the location of the lesion to be biopsied. The Advanced Breast Biopsy I nstru­ mentation ( A B B I ) device is another type of tissue acqu isition device that can be mounted to a stereotactic biopsy table. This method removes ti ssue by insertion of an oscil lating cannula with diameters measuring up to 2 cm, making it possible to remove a lesion as a single, intact spec­ i men, along with a large core of surround­ ing tissue. The cli nical value and efficacy of this method is sti l l being explored. '

Liberman L : Clinical management issues i n percu­ taneous core breast biopsy. Radial Ciill North Alii 3 8 : 79 1 . 2000. I

Needle-wire localization is a predomi­ nant method for localizing nonpalpable lesions. The four most common needle­ wire localization systems are the Kopans, Homer ( 1 8-gauge), Frank ( 2 1 -gauge), and H awkins (20-gauge) biopsy guides. With each system a long needle contai ning a hooked wire is inserted i nto the breast so that the tip approximates the lesion. A small incision ( I to 2 mm) at the entry site may be necessary to facilitate insertion of a larger gauge needle. Once the wire is in place, the needle i s withdrawn over the wire (Fig. 24-62) . The hook on the end of the wire anchors the wire within the breast

tissue. The surgeon cuts along the guide wire and removes the breast tissue around the wire's hooked end. Alternatively, the surgeon may choose an i ncision site that i ntercepts the anchored wire distant from the point of wire entry. Some radiologists also inject a small of amount of methylene blue dye to visually label the proper biopsy site. After needle-wire local iza­ tion, the patient is properly bandaged and taken to the surgical area for excisional biopsy (Fig. 24-63 ) . Ideal ly, the radiolo­ gist and surgeon should review the local­ ization i mages together before the exci­ sional biopsy.

Fig. 24-62 Mediolateral projection demonstrating needle-wire localization system within a lesion.

Fig. 24-63 Material for breast localization using specialized compression plate: alphanu­ meric localization compression plate, sterile gloves, topical antiseptic, alcohol wipe, local anesthetic, 5-ml syringe, 25-gauge needle, scalpel blade, sterile gauze, tape, and needle­ wire localization system.

BREAST LESION LOCALIZATION WITH A SPECIALIZED COMPRESSION PLATE Many mammography units have a special­ ized compression plate with an opening that can be positioned over a breast lesion. Through this opening a localizing needle­ wire can be introduced into the breast. The initial mammogram and a 90-degree lateral projection are u ually reviewed to­ gether to determi ne the shortest distance from the skin to the breast lesion. For ex­ ample, a lesion in the inferior aspect of the breast is best approached from the infe­ rior, medial, or lateral surface of the breast but not from the superior surface. The opening i n the specialized fenes­ trated compression plate may consist of a rectangular cutout with radiopaque al­ phanumeric grid markings along at least two adjacent sides. Alternatively, the plate may contain several rows of holes, each large enough to accommodate the inser­ tion of a localization needle (Fig. 24-64).

Needle-locali zation procedures vary from radiologist to radiologist. As a re­ sult, no standardized procedure exists. However, the fol lowing steps are typi­ cally observed: • Perform prelimjnary routine full breast projections to confirm the existence of the lesion (Figs. 24-65 and 24-66). Note that the MLO projection may be re­ placed by a 90-degree lateral projection.

• Obtain an informed consent after dis­

cussing the fol lowing subjects with the patient: I . Full explanation of the procedure 2. Full description of potential prob­ lems: vasovagal reaction, excessive bleeding, allergic reaction to lido­ caine, and possible failure of the pro­ cedure (failure rate of I % to 1 0% ) 3 . Answers to patient's preliminary questions

Fig. 24-65 Craniocaudal projection shown with specialized open-hole compression plate.

Fig. 24-64 Compression plates specifically designed for breast localization procedure.

...

...

Fig. 24-66 Mediolateral projection shown with specialized open-hole compression plate. 519

• Position the patient so that the com­

•

• A

B

•

•

Fig. 24-67 Preliminary projections for breast localization procedure. A, Lateral projection is obtained to determine depth of lesion (arrow). B, Compression plate immobilizes breast for needle-wire insertion on the craniocaudal projection. Note that the alphanumeric grid demonstrates that the lesion is located nearest to E-7 junction. The needle-wire will be Inserted through posterior aspect of hole E-7 .

• •

•

Fig. 24-68 Needle-wire localization device has been advanced through hole in compres­ sion plate to approximate location of lesion In cranlocaudal projection. 520

pression plate is against the skin sur­ face closest to the lesion as determined from the preliminary images. Tell the patient that compression will not be released until the needle has been successfully placed and that the patient is to hold as still as possible. Make a prelimi nary exposure using compression. Ink marks placed at the corners of the paddle window deter­ mine if the patient moves during the procedure. Process the image without removing compression. The resultant i mage shows where the lesion l ies in relation to the compression plate opening (Fig. 24-67) . C lean the s k i n o f the breast over the en­ try site with a topical antiseptic. Apply a topical anesthetic if necessary. Insert the localizing needle and guide wire into the breast perpendicular to the compression plate and paral lel to the chest wall, moving the needle directly toward the underlying lesion. Advance the needle to the esti mated depth of the lesion. Because the breast is com­ pressed in the direction of the needle's i nsertion, it i s better to pass beyond the lesion than to be short of the lesion. With the needle in position, make an exposure (Fig. 24-68). Then slowly re­ lease the compression plate, leaving the needle-wire system in place. Obtain an additional projection after the C-arm apparatus has been shifted 90 degrees (Fig. 24-69). These two radiographs are used to determine the position of the end of the needle-wire relative to the lesion.

• Reposition the needle-wire, and repeat

the exposures if necessary. • When the needle is accurately placed

within the lesion, withdraw the needle but leave the hooked guide wire in place. • Place a gauze bandage over the breast. • Tran port the patient to surgery along with the final localization i mages.

BREAST LESION LOCALIZATION WITHOUT A SPECIALIZED COMPRESSION PLATE If a specialized fenestrated compression plate is not available or preferred, the fol­ lowing procedure is observed: Obtain prelimi nary routine fu l l breast projections to confirm the exi tence of the lesion. The M LO projection may be replaced by a 90-degree l at­ eral projection. Obtain an informed consent after dis­ cussing the fol lowing subjects with the patient: I . Full explanation of the procedure 2. Full description of potential prob­ lem : va ovagal reaction, excessive bleeding, allergic reaction to l ido­ caine, and possible fai lure of the pro­ cedure (failure rate of I % to 1 0%) 3 . A nswers to patient' prelimi nary questions

Fig. 24-69 Second projection is obtained after x-ray tube is rotated 90 degrees. This pro­ jection allows depth of needle-wire localization system to be determined. Fenestrated compression plate is replaced with standard compression plate.

52 1

• Using the preliminary images, place an

• Fig. 24-70

Mammographer supports breast while physician superimposes craniocaudal projection mammogram over breast. This technique is used to locate breast lesion in ref­ erence to skin surface.

• •

•

• •

• •

Fig. 24- 7 1 Ink mark is placed on breast surface directly over breast lesion, locating lesion in craniocaudal projection. This technique is also used to place a mark over the lesion to locate the lesion in mediolateral projection.

522

i nk mark on the breast surface indicat­ ing the position of the lesion on each i mage. Taping alphanumeric radiopaque markers to the breast for the preliminary images can help to define the position of the lesion relative to the breast surface in each projection. Because the breast is compressed for the exposures, it must resemble the compressed position to ac­ curately place the markers. Using the hands, the mammographer reproduces this compression while the physician marks the surface of the breast at the ap­ propriate sites (Figs. 24-70 and 24-7 1 ). Triangulation of the two surface marks fi xes the three-dimensional location of the lesion. Clean the skin of the breast over the en­ try site with a topical antiseptic. Apply a topical anesthetic if necessary. Insert the needle, preferably parallel to the chest wall, toward the Ie ion for the predetermi ned distance (Fig. 24-72). Image the breast in the CC and 90degree l ateral projections with the needle-wire in place so that the exact location of the wire relative to the le­ s ion can be determ ined. Reposition the needle-wire, and repeat the exposures if necessary. When the needle is accurately placed within the lesion, withdraw the needle and leave the hooked guide wire in place (Figs. 24-73 and 24-74). Place a gauze bandage over the breast. Transport the patient to surgery along with the final localization images.

Fig. 24-72 Frank biopsy needle and guide wire is inserted into breast perpendicular to chest wall at site directly anterior to lesion. Site and depth of inser­ tion are selected by triangula­ tion using external skin marks.

Fig. 24-73 After inserting the needle and guide wire to depth of lesion, the needle is removed, leaving guide wire in place, Lateral skin mark used for select­ ing needle insertion site is seen (arrow),

Fig. 24-74 Craniocaudal and true lateral right-angle projec­ tions demonstrate relationship of wire to lesion, Needle has been removed,

523

STEREOTACTIC PROCEDURES Approximately 80% of nonpalpable le­ sions identified by mammography are not malignant. Nonetheless, a breast lesion cannot be defi nitely judged benign until it ha been microscopical ly evaluated. Stereotactic intervention, or stereotaxis, is a minor urgical procedure u ed to deter­ mine the benign or malignant nature of suspicious breast lesions . Stereotaxis guided by mammographic or ultrasound i maging is the preferred method for ob­ taining biopsy specimens of nonpalpable or equivocal ly symptomatic breast le­ sions. Most women with a mammo­ graphic and/or clinical breast abnormality are candidates for stereotactic core needle biopsy. The only exceptions are patients who cannot cooperate for the procedure, patients who have mammographic find­ ings at the Iimjts of perception, and pa­ tients with lesions of potentially ambigu­ ous histology.

Stereotaxis is used to differentiate be­ tween benign and malignant breast le­ sions. The benefits of stereotaxis over conventional surgical biopsy are less pain, less scarring, shorter recovery time, less patjent anxiety, and lower cost. Because stereotaxis can expedite pathology results, potential surgical deci­ sions such as those regardi ng lumpec­ tomy or mastectomy can be made with

Fig. 24-76

minimal delay. When operating on the ba­ sis of a core biopsy diagnosis of cancer, surgeons are more likely to obtain c lean (negative) lumpectomy margins with the first exc ision. A x i l l ary lymph nodes, which are evaluated to ascertajn metas­ tases, are also sampled at the time of the initial surgery. Thus the woman with a known diagnosis of breast cancer may avoid a second operation.

Prone stereotactic biopsy system with digital imaging.

(Courtesy Delta Medical Systems. Inc .. Milwaukee. Wisc.)

J

Fig. 24-75 Upright stereotactic system at­ tached to a dedicated mammography unit.

(Courtesy Trex Medical Corp LORAD Division. Danbury. Conn.) .•

524

Fig. 24-77 Open aperture in the table for prone biopsy system allows breast to be posi­ tioned beneath table.

(Courtesy Trex Medical Corp.. LORAD Division. Danbury. Conn.)

Stereotactic breast biopsy requires a team approach involving a radiologist, a mammographer, a pathologist, and a spe­ cially trained nurse. Stereotactic prone biopsy tables and upright add-on devices used for biopsy intervention are both com­ mercially available. The disadvantages of the upright add-on system include a l im­ ited working space, an i ncreased potential for patient motion, and a greater potential for vasovagal reactions (Fig. 24-75). The dedicated prone system is more expensive than the add-on system. It also requires a larger space and usually cannot be used for conventional mammography (Figs. 24-76 and 24-77). However, the success or fai l­ ure of core needle breast biopsy depends more on the experience and interest of the diagnostic team than on the particulars of the system that is used.

I n stereotactic breast biopsy, three­ dimensional triangulation is used to iden­ tify the exact location of a breast lesion. A digitizer calculates X, Y, and Z coordi­ nates (Figs. 24-78 and 24-79). The X co­ ordi nate identifies transverse location (right to left), the Y coordinate designates depth (front to back), and the Z coordinate identifies the height of the lesion (top to bottom). It is important to note that differ­ ent stereotactic systems will have differ­ ent methods for calculating a "z" value, depending on the center of rotation of the localization device. The user should be fa­ miliar with the system in use so that accu-

rate adjustments of the localization device can be made. Two exposures on a single image are taken at a difference of 30 degrees--one exposure at + 1 5 degrees and the other at I S degrees from the per­ pendicular. Precision of these angles is important. Also, with certain systems, the sequence of these i mages is significant in providing a correct value of lesion depth. The resultant i mage localizes the lesion in three dimensions. The "double exposed" image is referred to as a stereo image (Fig. 24-80). The physician can use the stereo i mage to determine the appropriate ap­ proach for reaching the breast lesion. -

�,--. - -

.

- -

�•• l.If l

Fig. 24-78 Digitizer calculates and transmits X,v. and Z coordinates to stage, or " brain," of biopsy system, where biopsy gun is at­ tached. This information is used to deter­ mine placement of biopsy needle.

Fig. 24-79

Stage of biopsy system supports biopsy gun. The X, V. and Z coordinates are displayed. (Courtesy Delta Medical Systems, Inc .. Milwaukee, Wisc.)

(Courtesy Trex Medical Corp.. LORAD Division. Danbury, Conn.)

Fig. 24-80 Stereo images demon­ strating three-dimensional vIsual­ ization of breast lesion before In­ tervention (arrows).

525

Before beginning the procedure, the physician reviews the i nitial mammo­ graphic images to determi ne the shortest distance from the surface of the skin to the breast lesion. If the exact lesion location i s identified, the biopsy needle can be in­ serted through the least amount of breast with only mini mal trauma to the breast. For example, a lesion located in the lateral aspect of the upper outer quadrant is ap­ proached from the lateral aspect, whereas a lesion located in the medial and superior portion of the breast is approached from above. After the best approach to the le­ sion has been determined, the affected breast is positioned and compressed for a scout image to localize the breast lesion. Once the breast lesion has been localized, tereo images are taken to triangulate the lesion 0 that proper coordinates can be calculated and dialed into the biopsy table stage. Imagi ng with stereotactic units i s available a s either conventional screen­ film or small field (5 X 5 cm) digital imaging. Although conventional screen­ film systems are considerably less expen­ sive, digital imaging is prefen-ed due to its shorter acquisition time. The breast is aseptical ly cleansed to mini mize infec­ tion. Pain associated with the procedure can be effectively managed using a local anesthetic to numb the skin at the area where the biopsy needle enters.

Three general methods can be used to localize a breast lesion. The physician's preference generally determines the pro­ cedure that is performed. With needle­ wire localization, the surgeon uses the hooked guide wire to find the biopsy site. I n FNAB cells are extracted from a suspi­ cious lesion with a thin needle. LeNB ob­ tains core samples of tissue by means of a larger needle with a groove adjacent to its tip. All three procedures can be performed using prone or upright stereotactic breast biopsy systems. However, because LeNB with stereotactic guidance is becoming the prefen'ed local ization method, it is dis­ cussed in depth in this chapter.

Fig. 24-81 Postfire stereo images demonstrating placement of biopsy needle inside lesion. 526

The physician decides where the first and subsequent passes ( biopsy needle travels through the breast tissue to reach the breast lesion) are to be made. After the skin is anesthetized, a small i ncision i s made with a scalpel t o facil i tate entry of the needle into the breast. A spring-loaded biopsy device is then used to power the needle back and forth through the target. A set of stereo i mages is obtained to con­ firm con-ect direction of the needle ( Fig. 24-8 1 ). The first pass is made by placing the biopsy needle within the lesion and obtaining a "postfire" image to confirm the correct needle placement. This image determi nes the course of ' subsequent passes. Redigitization (use of a digitizer to repeat the steps needed to calculate the new triangulation coordinates) can be per­ formed to obtain addi tional samples. Alternatively, the physician can estimate where to move the biopsy needle based on the i n itial needle location within the breast. It is important to remember that LeNB tissue samples are obtained using a needle with a groove adjacent to the nee­ dle tip. With the needle located inside the lesion, a sheath or needle cover sl ides over the groove of the needle. The sheath holds the tissue sample in place while the needle is withdrawn. When the needle is outside the breast, the sheath is pulled back, ex­ posing the tissue sample. The sample is then transferred to a specimen container for transportation to the laboratory. A minimum of 5 and as many as 20 tissue samples are obtained to ensure accurate sampling of the abnormality. The time re­ quired to perform a stereotactic procedure is approxi mately 40 to 50 mi nutes.

An alternative technique known as Mammotome uses a 1 4- or I I -gauge probe that is inserted under stereotactic or sonographic guidance to align the probe's aperture within the lesion. Tissue is gently vacuum aspirated into the probe's aper­ ture. A rotating cutter is advanced to cut and capture the tissue sample. The cutter is then withdrawn without removing the probe from the lesion, and the specimen is transported i n the cutter to a tissue col lec­ tion chamber. Multiple samples may be obtained by rotating the probe in vivo w ithout multiple insertions. Once the biopsy is complete, a radiopaque clip can be deployed through the probe and into the biopsy site to mark the area for future reference. The larger amount of tissue sampled with this technique is reported to i mprove accuracy in diagnosing atypical ductal hyperplasia and ductal carcinoma in situ lesions. I After the LCN B procedure is com­ pleted, the breast is cleansed and bandaged using sterile technique. Compression to the biopsy site is necessary to prevent ex­ cessive bleeding, and a cold compress is applied to mini m ize discomfort and swelling of the related tissues. The patient returns within 24 to 48 hours so that the breast can be examined to ensure that no bleeding or i nfection has occurred. The physician who performed the biopsy then discusses the biopsy re­ sults and subsequent treatment options, if applicable, with the patient.

Breast Specimen Radiography The suspected lesion must be contained in its entirety i n the tissue removed during the biopsy. Only very small lesions are characterized by tissue irregularity or mi­ crocalcifications that are nonpalpable in the excised speci men and may not be de­ tectable on visual i nspection. Compression of the specimen is necessary to identify le­ sions, especially lesions that do not con­ tain calcifications. Magnification images can help to better visualize microcalcifica­ tions. Specimen radiography is often per­ formed in an immediate postexcision pro­ cedure while the patient is still under anesthesia. Speed is therefore imperative. The fil m type, technical factors, and pro­ cedure for handling the specimen must be established before the procedure is started. Cooperation among the radiologist, mam­ mographer, surgeon, and pathologist is a necessity. Extremely fine-grain nonscreen fil m may be used because patient exposure is no longer a factor. The exposure factors depend on the thickness of the pecimen and the film that is used (Fig. 24-82).

It may be helpful to obtain one image of the breast speci men for the radiologist and another for the pathologi st. The pathologist often uses the specimen radi­ ograph to precisely locate the area of con­ cern. The next step is to match the actual specimen to the specimen radiograph be­ fore the specimen is dissected. Marking the area of concern by placing a ra­ diopaque object, such as a 1 - or 2-inch needle, directly at the area of concern helps the pathologist locate the abnormal­ ity more accurately.

' Dershaw DD: Equipment. technique, quality assur­ ance. and accreditation for image-guided breast biopsy procedures. Radial Ciill North Am 38:773,

2000 .

Fig. 24-82 Radiograph of surgical specimen containing suspicious microcalcifications. 527

Examination of Milk Ducts (Ductography) When a nipple discharge is localized in one of the multiple duct openings on the nipple, the milk duct can be studied using on opaque contrast medium. The purpose of the examination is to rule out an intra­ ductal mass as the possible cause of the discharge. The equipment and supplies for the examination i nclude the fol lowing: a sterile hypodermic syringe (usually I to 3 ml); a 30-gauge needle with a specially prepared, smooth, round tip; a skin cleans­ ing agent; sterile gauze sponges or cotton balls; a waste basin; and an organic, water­ soluble, iodinated contrast medium. After the nipple is cleansed, the round­ tipped needle or cannula is i nserted into the orifice of the duct, and 0.2 to 0.4 ml of undil uted iothalamate meg l u m i ne or iopamidol is gently injected. So that the patient does not experience unnecessary discomfort and extravasation does not oc­ cur, the injection is terminated as soon as the patient experiences a sense of fullness or pai n. If cannulation is unsuccessful, a sterile local anesthetic gel or warm com­ press may be applied to the nipple and areola and the procedure is reattempted. I f ductography is unsuccessful after three at­ tempts, the procedures may be resched­ uled in 7 to 1 4 days. Upon successful in­ jection, the fol lowing guide l i nes are observed:

• I mmediately obtain radiographs with

the patient positioned for the CC and lateral projections of the subareolar re­ gion using magnification technique (Fig. 24-83). I f needed, MLO or rolled CC and rolled MLO magnification pro­ jections may be obtained to resolve su­ perimposed ducts. • Employ the exposure techniques used in general mammography. • Leave the cannula in the duct to mini­ mize leakage of contrast material dur­ ing compression and to facilitate rein­ jection of the contrast medium without the need for recannulation. • If the cannula is removed for the im­ ages, do not apply compression be­ cause it would cause the contrast medium to be expelled.

Computer-Aided Detection and Computer-Aided Diagnosis When performing mammographic inter­ pretation, the radiologist must locate any suspicious lesions (sensitivity) and then determine the probability that the lesion is malignant or benign (specificity). Even with high-quality screen-fi l m mammogra­ phy, some breast cancers are missed on initial interpretation. Double-readi ng of screening mammograms by a second radi­ ologist can i mprove detection rates by ap­ proximately 1 0% . ' Recently efforts have been made to develop and apply a com­ puter-aided detection system to achieve the same result as double-reading. ' Kopans D B : Double reading, Radiol c/in North Am 38:7 1 9, 2000 .

Fig. 24-83 Craniocaudal projection of opacified milk ducts. 528

Computer-aided detection and com­ puter-aided diagnosis (CAD) are methods by which a radiologist can use computer analysis of digitally acquired images as a " econd opinion" before making a fi nal interpretation. CAD requires that the mammographic i mage exist in a digital format to faci l itate computer input. This i s more commonly accomplished with use of an optical scanner, however, i mages di­ rectly acquired with digital techniques is emerging as a preferred method. The computer may detect lesions that are m issed by the radiologist, thereby mini­ mizing the possibility of false-negative readi ngs ( Fig. 24-84). Once a lesion is de­ tected, the computer can be programmed with basic algorithms to estimate the l i ke­ lihood of malignancy, thereby i ncreasing true-positive rates. Ultimately, the objec­ tive of this technology is to improve early detection rates and minimize the number of unnecessary breast biopsies. Another advantage of CAD is that computers are not subject to bias, fatigue, or distractions. Multicenter studies are being conducted to determine the sensitivity of computer detection programs. The sensitivity of CAD for detecting clusters of microcalcifi­ cations has been shown to approach 90%. ' In another study, one algorithm has been shown to identify more than 80% of missed lesions that proved conspicuous in retro­ spect. The e results have led the U.S. Food and Drug Administration to approve a commercial computer-aided detection system for clinical use. 2 The sensitivity of CAD for correctly identifying microcalci­ fications i remarkable (98% accuracy). In the identification of masses, CAD demonstrated a 74.7% accuracy. Further­ more, during clinical application, CAD has not shown a signi ficant increase i n fal se-positive mammograms.

CAD has demonstrated meaningful clinical application not only in screening mammography but also in the analysis of basic chest radiography and computed to­ mography of the lung. The successful cl inical application of CAD in these areas will certainly result in its complete inte­ gration with full-field digital i maging sys­ tems in the future. Innovative approaches to ful l breast digital i maging will continue to be devel­ oped. The ulti mate goal of these pursuits should not be lost in the technology itself or in the formidable economic climate of health care today. The purpose of breast cancer screening is to save lives, regard­ less of the method or medium. The effi­ cacy of mammography has been proved. The continued i mprovement of mammo­ graphic i mage quality by using digitally based i mage manipulation, and progress­ ing away from fi l m altogether, is a method by which the outcomes for patients with breast cancer can be i mproved long before a cure for the disease is found.

Thermography and Diaphanography Beginning in the 1 950s, thermography and diaphanography were actively investi­ gated in the hope that breast cancer and other abnormalities could be diagnosed using nonionizing forms of radiation. These two diagnostic tools are seldom used today. Thermography is the photograph record­ ing of the infrared radiation emanating from a patient's body surface. The resulting thermogram demonstrates areas of in­ creased temperature, with a temperature in­ crease often suggesting increased metabo­ lism. (More complete information on this technique is provided in the fourth through eighth editions of this atlas.) Diaphanography is an examination in which a body part is transi lluminated us­ ing selected l ight wavelengths and special i maging equipment. With this technique the interior of the breast is inspected using l ight directed through its exterior wal l . The l ight exiting the patient's body is then recorded and interpreted. The rapid ad­ vances in mammography have essentially elimi nated the use of the technique for evaluating breast disease. (More complete information on diaphanography is given in this chapter in the fourth through eighth editions of this atlas.)

'Yybomy C J , e l al: Computer-aided detection and diagnosis of breast cancer, Radial Clin North Am 38:725 , 2000 . 'Roehrig J, et aJ: Clincal results with R2 image checker system. In Karssemeijer N, et aJ (eds): Digital imaging '98, Dordrecht, The Netherlands, 1 998, K1uwer Academic.

Fig. 24-84 Bilateral MLO projections with CAD markers. These images were digitally ac­ quired by an optical scanner and analyzed by a computer. Areas indicated by markers were benign,

(Courtesy R2 Technology, Inc. Los Altos, Calif.) 529

Summary Radiographic examination of the breast i a techn ical ly demanding procedure. Success depends in large part on the skills of the mammographer-more so than in most other areas of radiology. I n addition to skill the mammographer must have a strong desire to perform high-qual ity mammography and must be willing to work with the patient to allay qualms and to obtain cooperation. In the course of tak­ i ng the patient's history and physically as­ sessing and radiographing the breasts, the mammographer may be asked questions about breast disease, B S E , screening guidelines, and breast radiography that the patient has been reluctant to ask other health care professionals. The knowledge, skill, and attitude of the mammographer may be lifesaving for the patient. Although most patients do not have significant breast disease when first examined, statis­ tics show that approxi mately 1 2% of pa­ tients develop breast cancer at some time during their l ifetime. An early positive mammography encounter may make the patient more willing to undergo mammog­ raphy in the future. When properly per­ formed, breast radiography is safe, and it presently is the best hope for significantly reducing the mortality of breast cancer. Selected bibliography

Adler 0, Wahl R: New methods for imaging the breast: techniques, findings and poten­ tial, AlR 1 64 : 1 9, 1 995. American Cancer Society: Breast cancer facts & figures 1 999/2000, http://www.cancer. org/ (accessed April 200 1 ). Appelbaum A et al: Mammographic appear­ ance of male breast disease, Radiograph ics 1 9: 559, 200 I . Bassett L: Clinical image evaluation, Radiol Ciin North Am 33: 1 027, 1 995. Bassett L: I maging of breast masses, Radiol Ciin North Alii 38:669, 2000. Bassett L, Heinlein R: Good positioning key to imaging of breast, Diagn Imaging 9:69, 1 993. Bassett L et aI, editors: Qllality determinants of mammography. AHCPR Pub No 950632, Rockvil le, MD, 1 994, US Depart­ ment of Health and Human Service .

530

B urbank F: Stereotactic, breast biopsy of atyp­ ical hyperplasia and ductal carcinoma in situ lesions: i mproved accuracy with direc­ tional, vacuum-assisted biopsy, Radiology 202:843, 1 997. B urbank F, Parker SH, Fogarty TJ: Stereotactic breast biopsy: i mproved tissue harvesting with Mammotome, Am Surg 62:738, 1 996. Carr J et al: Stereotactic localization of breast lesions: how it works and methods to im­ prove accuracy, Radiographics 2 1 :463, 200 I . Dershaw DO et al: Mammographic findings in men with breast cancer, AlR 1 60:267, 1 993. Dershaw DO: Equipment, technique, quality assurance, and accreditation for image­ guided breast biopsy procedures, Radiol Ciin North Am 38:773, 2000. Donegan WL: Cancer of the male breast. I n Donegan W L , Spratt J S , editors: Cancer of the breast, ed 4, Philadelphia, 1 995, W B Saunders. Eklund GW, Cardenosa G: The art of mammo­ graphic positioning, Radiol Clin North Am 30:2 1 , 1 992. Eklund GW et al: I mproved imaging of the augmented breast, AlR 1 5 1 :469, 1 988. Feig S: Breast masses. Mammographic and sonographic evaluation, Radiol Clin North Am 30:67, 1 992. FundamentaLs of mammography: the quest for quality positioning guidebook for radioLogic technologists, Albuquerque, 1 993, American

Society of Radiologic Technologists. Haus A, Yaffe M: Screen-film and digital mammography image quality and radiation dose considerations, Radiol CLin North Am 38:87 1 , 2000. Healy B: BRCA genes: bookmarking, for­ tunetelling, and medical care, N Engl 1 Med 336: 1 448, 1 997 (editorial ) . Henderson IC: Breast cancer. In Murphy GP, Lawrence WL, Lenhard RE, editors: Clinical oncology, Atlanta, 1 997, American Cancer Society. Homer M, Smith T, Safaii H: Prebiopsy needle localization. Methods, problems, and ex­ pected resu l ts, Radiol Clin North Am 30: 1 39, 1 992. Jackson V: The status of mammographically guided fine needle aspiration biopsy of non­ palpable breast lesions, Radiol Clin North Am 30: 1 55, 1 992. «jmme-Smith C : New and future develop­ ments in screen-fil m mammography equip­ ment and techniques, Radiol Clin North Am 30:55, 1 992. Kopans DB: Double reading, Radiol Clin North Am 38:7 1 9, 2000.

Krainer M et al: Differential contributions of B RCA I and B RCA2 to early-onset breast cancer, N EngL 1 Med 336: 1 4 1 6, 1 997. Liberman L : Clinical management issues in percutaneous core brea t biopsy, Radiol Clin North Am 38:79 1 , 2000. Love S: D,: Susan Love 's breast book, ed 2, Reading, Mass, 1 995. Mammography quality controL manuaL, rev. ed, Chicago, 1 999, American College of Radiology. National Cancer I nstitute CancerNet. http://www.cancernet.nci.nih.gov/(accessed April 200 1 ). Nishikawa R et al: Computerized detection of clustered microcalcifications: evaluation of performance on mammograms from multi­ ple centers, Radiographics 1 5 :443, 1 995. Orel S G : M R i maging of the breast, Radiol Clinc North Am 38: 899, 2000. Parker SL, Burbank F: A practical approach to minimally invasive breast biopsy, Radiology 200: I I , 1 996. Parker S L et al: Percutaneous l arge-core breast biopsy: a multi-institutional study, Radiology 1 93 :359, 1 994. Parker SL et al: Cancer statistics, 1 997, CA -A Cancer 1 CUn 47 :5, 1 997. Prechtel K, Pretchel V: Breast carcinoma in the man. Current results from the viewpoint of clinic and pathology, Pathologe 1 8:45, 1 997. F-D-C Reports, Inc: Image Checker unani­ mously endorsed by radiology paneL, Medical devices, diagnostics, and instru­ mentation: "the gray sheet," 24:20, 1 998.

Roehrig J, et al : Clincal results with R2 im­ agechecker system. In Karssemeijer N, et al (eds): Digital imaging '98 Dordrecht, The Netherlands, 1 998, Kluwer Academic. Rozenberg S et al: Principal cancers among women: breast, lung and colorectal, 1111 1 Ferti/ 4 1 : 1 66, 1 996.

Schmidt R, Wolverton 0, Vyborny C: Computer-aided diagnosis in mammography. In Syllabus: RSNA categorical course in breast imaging, Oak Park, III, 1 995, RSNA. Skolnick AA: U ltrasound may help detect breast implant leaks, lAMA 267(6):786, 1 992. Slawson SH et al: Ductography: how to and what if? Radiographics 2 \ : 1 33, 200 1 . Vyborny CJ: Computer-aided detection and computer-aided diagnosis of breast cancer, Radiol Ciin North Am 38:725, 2000. Wentz G: Mammographyfor radiologic technol­ ogists, ed 2, New York, 1 997, McGraw-HilI.