is Associate Professor of Radiology at the University of Virginia School of Medicine in Charlottesville, where he is head of the Section of Gastrointestinal Radiology and coordinator of Digital Fluorography. Dr. Shaffer obtained his M.D. degree from West Virgina University. After interning at Memorial Hospital in Charleston, West Virginia, he completed residency and fel- lowship training in diagnostic radiology at the University of Virginia School of Medi- cine. Dr. Shaffer’s primary professional in- terest is in radiology of the alimentary tract, although he has also published arti- cles about skeletal radiology.

INFLAMMATORY DISEASE OF THE LARGE BOWEL may be due to one of a variety of specific agents or may have no known cause. The known causes can be broadly categorized as either infectious agents or physical agents (Table 1). In the United States and Europe the majority of cases of colitis are idiopath- ic, namely, ulcerative colitis and granulomatous (Crohn’s) co- 1itis.l

Because the colon has a limited number of responses it can make to a variety of insults, there may be overlap of radiologic findings in many types of colitis (Table 2). The many forms of inflammatory disease for which a cause is known may have radiologic features which are indistinguishable from ulcerative colitis and Crohn’s disease. The various types of specific colitis must be excluded by clinical history and appropriate bacterio- logic and histologic studies, before placing a patient with colitis into the idiopathic group. Once consideration is narrowed to id- iopathic forms of inflammatory disease, characteristic radiologic features will usually distinguish ulcerative colitis from Crohn’s disease of the large bowel.

PURPOSE OF A BARIUM ENEMA

The radiologist is frequently consulted to perform a contrast study of the large bowel in a patient with known or suspected inflammatory bowel disease. In order to determine the method of treatment and prognosis for the patient, the clinician seeks answers from the radiologist to the following questions: (1) Does the patient have colitis ?; (2) If so, can a diagnosis of the specific

6

TABLE L-PATHOLOGIC CLASSIFICATION OF COLORECTAL INFLAMMATORY DISEASE

Infectious Agents Bacterial

Parasitic

Viral Fungal

Physical Agents Extrinsic Intrinsic

Shigella, Salmonella, E. coli, Campylobacter, Yersinia N. gonorrhea, M. tuberculosis, Chlamydia (lymphogranuloma venereum), Clostridium difficile (pseudomembranous colitis)

Schistosomiasis, amebiasis, balantidiasis, cryptosporidiosis, strongyloidiasis

Cytomegalovirus, herpes simplex Histoplasmosis

Antibiotic-related, cytotoxic drugs, irradiation Ischemia, diverticulitis, solitary ulcer syndrome,

obstruction related Idiopathic-Crohn’s disease, ulcerative colitis

type be made?; (3) What is the extent and severity of the dis- ease?; and (4) Are any complications of the disease present?

WHEN SHOULD A RADIOLOGIST DECLINE TO PERFORM THE BARIUM ENEMA?

A barium enema is contraindicated in any patient with clini- cal or radiographic evidence of toxic megacolon or perforation.‘? 3 It is also wise to defer contrast studies in patients who are acutely ill with colitis until they have been treated and show good response to therapy.3Y 4 This will not alter management of the patient because medical therapy is the same for both acute ulcerative colitis and acute Crohn’s disease.

COLON PREPARATION: How VIGOROUS SHOULD IT BE?

Prior to a barium enema for any reason, colon preparation should be the best that can be safely obtained.5 In the patient with quiescent disease or mild symptoms, routine bowel prepa- ration should be used. We use a slight modification of the pro- cedure devised by Garland R. Brown,’ which involves four basic steps: (1) Clear liquid diet for 24 hours prior to the examination; (2) Overhydration of the patient in preparation for hypertonic saline-type cathartic purge; (3) Saline-type cathartic purge (magnesium citrate) to rid the colon of major fecal material and to expose the colonic mucosa for a contact-type evacuant; and (4) Contact-type evacuant (bisacodyl tablets and suppository) to rid the colon of fine residual fecal material by peristaltic contrac- tions.

This procedure produces a satisfactorily clean colon in more than 90% of patients. Many radiologists believe that cleansing enemas are necessary.” *, ’

7

TABLE 2.-&JMMARY OFTHEPREDOMINANTRADIOLOGICFEATURES IN COLITIS

RADIOLOGIC FEATURE COMMONLY FOUND IN MAY BE FOUND IN

Granular Mucosa

Ulceration Discrete

Confluent shallow

Confluent deep

Stricture Formation Symmetric

Asymmetric

Fistula

Inflammatory Polyps

Small Bowel Involvement

Sl+p Lesions

Toxic Megacolon

Ulcerative Colitis

Crohn’s disease Yersinia enterocolitis Behcet’s disease Ulcerative colitis

Crohn’s disease

Ulcerative colitis Lymphogranuloma

venereum Crohn’s disease Ischemia Tuberculosis Crohn’s disease Lymphogranuloma

venereum Ulcerative colitis Crohn’s disease Schistosomiasis (Colitis cystica profundal Yersinia enterocolitis Tuberculosis Pseudomembranous

enterocolitis Crohn’s disease Crohn’s disease Tuberculosis Amebiasis Ulcerative colitis

Campylobacter colitis Herpes proctitis Gonococcal proctitis

Amebiasis Ischemia Tuberculosis Crohn’s disease Amebiasis Ischemia Amebiasis Tuberculosis Strongyloides colitis

Tuberculosis

Tuberculosis

Ischemia (rare)

Ulcerative colitis (back- wash)

Behcet’s disease Ischemia

Lymphogranuloma venereum

Crohn’s disease Ischemia Amebiasis

Adapted from Laufer I.: Double Contrast Gastrointestinal Radiology with Endoscopic Correlation. Philadelphia, W.B. Saunders Co., 1979, p. 684. Used with permission.

In the patient with subacute inflammatory disease, less vig- orous preparation is used. The clear liquid diet and hydration are maintained. Mild laxatives or a tap water enema are pre- scribed for the final bowel cleansing.

In the patient with active colitis, full bowel preparation might cause considerable distress and is contraindicated. Fortunately, with ulcerative colitis, an adequate limited examination can be achieved with no preparation. This is possible because the dis-

8

ease involves the distal nart of the colon and is alwa.vs in conti- nuity. Since no fecal residue will accumulate adjacent to an in- flamed mucosa, the affected colon is internally cleansed. A barium enema confined to this area can be obtained for satisfac- tory interpretation, This limited examination of the unprepared bowel, also known as the “instant enema,” is not successful with Crohn’s disease because of its discontinuous nature. The inter- vening segments of normal mucosa prevent the same internal cleansing action in the co1on.i’ 2

PRELIMINARY ABDOMINAL FILM

A plain film of the abdomen should always precede any bar- ium enema. This excludes contraindications to the examination, such as toxic megacolon or perforation, and to evaluate the ad- equacy of the bowel preparation.

BARIUM ENEMA, WHICH TYPE?

Should the patient have a conventional barium enema or a double contrast enema? Both methods are effective in revealing advanced colonic disease. However, the single contrast barium enema frequently will not detect early or mild forms of disease confined to the mucosa. Overall accuracy of the single contrast enema in differentiating ulcerative colitis from granulomatous colitis is approximately 75%. i0 The double contrast technique can improve accuracy to more than go%.‘, l1

The double contrast enema allows the radiologist to detect in- flammatory disease in its early stages, when only superficial mucosal changes are present. More accurate assessment of ex- tent of disease is also possible. There is no data to suggest that the double contrast enema is any more hazardous or uncomfort- able than the single contrast barium enema in patients with in- flammatory disease.2, 3T 4* 5, I2

THE NORMAL COLON

In order to evaluate the large bowel for the presence or ab- sence of disease, one must first recognize its normal appearance (Fig 1). In the double contrast study, the mucosa is coated with a thin, homogenous layer of barium. The lumen is distended with air. The en face appearance of the mucosa is generally more informative than the appearance of the contour of the bowel. The normal mucosa is completely smooth and featureless except for the haustral markings. The profiled contour of the normal bowel is extremely smooth and seen as a very thin line of bar-

9

Fig l.-Right lateral view of normal rectum. Mucosa is completely smooth and featureless except for valves of Houston and haustral markings. Mucosal detail of this quality is achieved by attention to thorough colon preparation, superior coating with modern barium suspension, optimal distension with air, and careful radiographic technique.

ium coating. 47 5,11 Mucosal detail of the quality illustrated in Figure 1 is necessary if the early changes of inflammatory bowel disease are to be detected.

ULCERATIVE COLITIS

MUCOSAL CHANGES

The radiographic changes of mild or early ulcerative colitis are confined to the mucosa. Characteristics are confluent gran- ularity, circumferential symmetry of involvement, and longitu- dinal continuity of disease.” Granularity is the earliest or mild- est mucosal abnormality that can be detected by double contrast enema*2. 3,5, 12 The smooth, even texture of the barium coating the normal mucosa is lost and becomes amorphous or finely stip- pled (Fig 2). Seen in profile, the fine, even mucosal line is slightly thickened and indistinct but shows no serration. The fine granularity is the result of mucosal edema and hypere-

10

Fig 2.-Lateral rectum with changes of mild, active ulcerative colitis. Mucosal edema and hyperemia impart an appearance of granularity to the mucosa see en face. There is no serration along the profiled mucosal margin.

mia.i, ‘a 3, 5, l1 Recognition of this granularity enables the radiol- ogist to detect ulcerative colitis with more confidence and at an earlier stage than is possible using single contrast tech- niques.” 3, 5 The granularity persists after the ulcerative stages develop.

Mucosal ulceration indicates severe, acute disease.2, 5 This is difficult to identify en face. The presence of ulceration is dis- ruption of the mucosal line at the margin of the bowel by small protruding spicules (Fig 3). Shallow ulcerations on a back- ground of diffuse granularity is characteristic of ulcerative colitis.2, l1

Continuous, symmetrical disease extends from the rectum un- til a proximal limit is reached where there is a rather short transition to normal mucosa (Fig 4). Ulcerative colitis involves the rectum histologically in at least 95% of cases.13 Radiograph- ically, however, the rectum does not appear to be involved in 1520% of patients38 4, “7 l2 and the distal extent of disease ap- pears to be in sigmoid colon (Fig 5). In many cases where rectal involvement can be shown, the changes appear less severe than in the sigmoid and descending colon. Even when rectal involve- ment cannot be radiographically confirmed, the confluent gran- ularity and the continuity and symmetry of disease in the more proximal colon will establish the diagnosis as ulcerative colitis (Fig 6).11

11

Fig 3.-Moderately severe, active ulcerative colitis. Shallow ulcers are present on a background of diffuse granularity. Ulcers are easiest to identify along the bowel margin as protruding mucosal spiculations.

12

Fig 4. .-Ulcerative colitis. Longitudinally continuous and circumferentially syn rical gra lnularity extends from the rectum to the hepatic flexure, where there is sition to normal mucosa. Diffuse ulceration is present in the descending colon. ures 2 i md 3 are detailed views of the same case.)

tran. (Fig.

13

Fig L-In the prone angled view, the rectum appears to be disease free with ulcerative colitis beginning in the sigmoid colon. Although the rectum is almost al- ways involved first, it is often the site of earliest response to treatment.

EXTENT OF INVOLVEMENT Involvement of the large bowel with ulcerative colitis varies

from localized disease in the rectum (Fig 7) to total colonic dis- ease (Fig 8). The double contrast enema underestimates the length of involvement in two thirds of cases when compared with colonoscopy. However, it is still more accurate than the conventional barium enema. On the average, the difference is approximately one third of the entire length of the colon.14 If the barium enema demonstrates disease to the level of the hepatic flexure, the patient may have total colon involvement histologi- cally.5, i5 Determining length of involvement is important be- cause patients with total colitis radio ~a@n~ally constitute a higher risk group to develop carcinoma. ’

14

Fig 6.-Although the rectum is radiographically spared, the continuous, symmet- rical inflammatory changes extending from the sigmoid colon to the hepatic flexure establish the diagnosis as ulcerative colitis. (Same case as figure 5.)

TERMINAL ILEUM

The terminal ileum is normal in the majority of patients with ulcerative colitis. The so-called back-wash ileitis is present only in association with total colitis, usually of long standing. Char- acteristic features are dilatation, absent peristalsis, and a gran- ular mucosa (Fig 9). Ulceration is not present. The ileocecal valve is usually dilated and incompetent. Radiologically, ileal involvement is of little significance except to confirm the pres- ence of total colitis.2

POLYPOID LESIONS

There are three types of polypoid-appearing lesions which may be seen with inflammatory disease of the colon: pseudopolyps, inflammatory polyps, and postinflammatory polyps. In the acute severe attack of ulcerative colitis with deep ulceration, islands of spared mucosa may be seen in a sea of diffuse ulcerations. These inflamed mucosal remnants may be called pseudopolyps since they represent the actual mucosal surface and not polypoid protuberances extending above it (Fig 10L2

15

Fig 7.-Ulcerative proctitis. The diffuse mucosal granularity terminates at the rectosigmoid juncture.

In patients with low grade activity, localized polypoid lesions may be seen in an area of diffuse mucosal granularity. These localized mounds of mucosal inflammation are called inflamma- tory polyps. They are polypoid protuberances on a background of acutely inflamed mucosa (Fig ll).’

A variety of polypoid configurations are found in patients with quiescent disease. Referred to as postinflammatory polyps, they are protuberances of either inflamed or normal mucosa which project into the lumen from the healed bowel wall (Fig 12). They may be single or multiple, segmental or diffuse, small, sessile nodules or long, worm-like outgrowths from the mucosa which branch and adhere to each other.2 These fmEer-like projections have been termed filiform polyps (Fig 13). At times, filiform polyps are attached at both ends, forming mucosal bridges.lg 2o

Pseudopolyps, inflammatory polyps, and postinflammatory polyps are not true neoplasms and have no malignant poten- tial. s Most have a rough surface and an irregular contour which allows them to be distinguished from small adenomatous polyps which are round, sessile, and covered by a smooth mucosa. They

16

, occur in both ulcerative colitis and granulomatous colitis and are the nonspecific product of severe inflammatory disease.” 3

SECONDARY CHANGES

In addition to mucosal disease, secondary changes occur in the colon wall with chronic ulcerative colitis and are probably the result of smooth muscle hypertrophy.21 The rectal lumen may appear uniformly narrowed. This is associated with reciprocal widening of the postrectal space. The valves of Houston in the rectum may be obliterated (Fig 14). The haustration in the colon may also be obliterated throughout the affected portion of the bowel (Fig 15). This is often associated with narrowing of the bowel lumen. The colon may be shortened with disease progres- sion, causing the flexures to assume a low position (Fig 16).l, 2 These changes indicate that long standing, active disease is present. When this primarily mucosal disease regresses, the co- lon wall can revert to an entirely normal appearance,2 confirm- ing that the secondary changes are not due to fibrosis.

Fig &-Ulcerative pancolitis seen in the right lateral decubitus view. Continuous granularity from the rectum to the cecum indicates the presence of active inflam- mation. Note secondary changes of luminal narrowing and absence of haustration.

Fig 9. -Ulcerative pancolitis with backwash ileitis. Cecal spot film shows gran ular sa without ulceration in the dilated terminal ileum. lleocecal valve is patulol US.

18

lO.-Severe, active ulcerative with pseudopolyps. In the splenic

8, islands of spared mucosa stand a sea of confluent ulcerations.

19

Fig Il.-Mild, active ulcerative colitis with inflammatory polyps in the distal as- cending colon. A larger, lobulated, pedunculated polyp and a smaller, smooth, ses- sile polyp (arrow) are present on a diffusely granular mucosa.

20

Fig 12.4nactive ulcerative colitis with postinflammatory polyps of the distal de- scending colon. These polyps have a variety of shapes, including filiform. Although they are the product of previously severe inflammation, note that the surrounding mucosa has returned to normal.

21

Fig 13.~-Surgical specimen demonstrating postinflammatory filiform polyps.

COMPLICATIONS

Strictures are usually found when colitis has been present for more than five years and where there is total colonic involve- ment.22 They are of variable length, and may be multiple; most strictures are benign. 23 Typically, a benign stricture has smoothly tapering margins with a symmetric central lumen and

Fig 14.-Mild active ulcerative proctitis seen in two projections. In addition to diffuse mucosal granularity, there are secondary changes of luminal narrowing with reciprocal widening of the post rectal space and obliteration of the valves of Houston.

Fig 15.-Active ulcerative colitis from the rectum to the ileocecal valve. Along with mucosal disease in the involved portion of the colon, there are secondary changes of luminal narrowing and loss of haustration. (See also Figure 4.)

a mucosa throughout that is similar to that on either side of the stricture. The less common strictures due to advanced malig- nancy usually have irregular margins with uneven narrowing, an eccentric lumen, and an irregular mucosa which differs from the mucosa beyond the stricture (Fig 16).24 The distinction be- tween benign and malignant strictures is frequently difficult to make on a purely radiologic basis, however, and endoscopic ex- amination and biopsy are indicated.’

Carcinoma develops in 3-4% of patients with ulcerative coli- tis, an incidence which is about ten times that of the normal population.26, 26 The average age for development of malignancy is about 35 years in those with ulcerative colitis as compared with 60 years in the normal population.26 Carcinoma associated with ulcerative colitis develops insidiously and does not become clinically or radiographically evident until far advanced.” 27 Multiple synchronous malignancies are found in about one third of cases.28 Association with adenomatous polyps is rare; infil- trating malignancy is more characteristic (Fig 17).

23

Fig 16.-Chronic, active ulcerative pancolitis of 15 years’ duration. Colon is shorted with the flexures in low positions. Note diffuse severe mucosal ulceration outlining pseudopolyps. The lumen is reduced in caliber and haustrations are obliter- ated. Backwash ileitis is present. Strictures of the ascending and descending colon represent infiltrating carcinomas.

Epithelial dysplasia occurs in association with carcinoma in 80-100% of resected specimens. In patients with biopsy evidence of rectal dysplasia, an unsuspected carcinoma will be found in approximately 40% of specimens resected during proctocolec- tomy. Although Frank and associates27 have recently suggested that epithelial dysplasia can be recognized on double contrast enemas as irregular nodules with sharply angulated edges, these precancerous lesions cannot be identified consistently by radiography in the presence of active inflammation (Fig 18).l

Most authorities agree that serial barium enemas are not the best way to observe colitis patients at high risk for malignancy because the typical insidious cancer is commonly far advanced before it can be detected.’ Alternative choices are frequent total colonoscopies with multiple biopsies or prophylactic proctocolec- tomy.

CROHN’S DISEASE

Crohn’s disease may affect every part of the gastrointestinal tract, but has a particular affinity for the terminal ileum and right colon. The recent National Cooperative Crohn’s Disease

24

Study found that the co& was involved in approximately 70% of patients, 15% having disease confined to the colon alone.2g This transmural inflammation is characterized by marked thick- ening of the bowel wall and involvement of regional lymph nodes. There is a tendency toward the formation of deep ulcers, abscesses, and fistulae. Crohn’s disease is characterized in its earliest stages by discrete, small ulcers on a background of nor- mal mucosa. As it progresses, multiple areas of severe disease may be separated by normal mucosa or areas of minimal dis- ease. This tendency for asymmetry and discontinuity is in marked contrast to the symmetrical and continuous involvement of the colon in ulcerative colitis.13 2Y 3, l1

MUCOSAL CHANGES

Aphthous ulceration is the earliest pathologic and radio- graphic sign of Crohn’s colitis. 3, 21p 30, 31 The aphthous ulcer is recognized as a central collection of barium surrounded by a ra- diolucent halo about 1 mm wide on a background of normal mu- cosa (Fig 19).3* ‘I3 31 Its characteristic appearance is produced by inflammation and enlargement of a submucosal lymphoid nod-

Fig 17.-Chronic, active ulcerative pancolitis. Infiltrating adenocarcinoma of sig- moid colon (arrows) was a Duke’s A lesion at time of proctocolectomy.

25

Fig 18.-Severe, active ulcerative colitis of long duration. infiltrating carcinoma surrounded by epithelial dysplasia in the proximal descending colon cannot be dis- tinguished radiographically in the midst of confluent ulceration with pseudopolyps. Pathologic diagnosis was made from the proctocolectomy surgical specimen.

ule with central ulceration of the overlying epithelium.21P 31 It may range in size from a pinpoint erosion up to a few millime- ters in diameter.

Aphthous ulcers are not specific for Crohn’s disease and may be seen in less common conditions such as Yersinia colitis, Beh- cet’s syndrome, and amebic colitis.‘, 3, 31 They are rarely, if ever, seen in ulcerative colitis.r* ‘7 3 Aphthous ulcers are convincingly shown by the double contrast enema.2

DISCONTINUOUS ULCERATION

The tendency for discontinuity of ulceration is one of the main hallmarks of Crohn’s disease.r* 2, 3 In the earliest stages, aphthous ulcers are separated by a normal mucosa (Fig 20). As the ulcers become more numerous, patches of normal mucosa “ski P areas” can still be identified in between them (Fig 21). ' 3P 3oP 32 As the ulcers enlarge, they often become irregular

26

in outline and may lose’their surrounding halos. Adjacent ulcers may coalesce forming a network of confluent ulcers and take on the appearance of serpiginous longitudinal excavations. These pleomorphic ulcers and fissures are manifestations of severe dis- ease.31

ASYMMETRY

In addition to discontinuity, asymmetric involvement of the circumference of the bowel is a major hallmark of Crohn’s dis- ease.3 In the early stages, this may be manifest by involvement of one wall, while the opposite bowel wall remains completely normal (Fig 22). Even in more advanced disease, where the en- tire circumference is involved, there will be asymmetry in the severity from one side to the other (Fig 23). As fibrosis ensues, asymmetric scarring may cause severe contraction of one wall, while the less involved wall can balloon out in sacculations, sometimes described as “pseudodiverticula” (Fig 24j.l. 27 3

OTHER MANIFESTATIONS

In severe disease, serpiginous longitudinal and transverse ul- cers occur and produce the typical cobblestone mucosa.2 The lin- ear ulcers demarcate rather square or rectangular blocks of mu-

Fig lg.-Early Crohn’s colitis. Three aphthous ulcers (arrows) surrounded by nor- mal mucosa are present in the ascending colon.

27

Fi ig 20.- -Early Crohn’s colitis with multiple aphthous ulcers (arrows) mal descen ding colon. Note that the mucosa is otherwise normal.

in the proxi-

28

Fig 21.-Crohn’s disease, more severe than in Figure 20. Although aphthous ul- cers are numerous in the descending colon, “skip areas” of intervening normal mu- cosa are still present. Very severe inflammation in the transverse colon has obliter- ated all normal mucosa and confluent ulcers take on linear and pleomorphic shapes.

29

Fig 22.-Crohn’s disease with characteristic circumferential asymmetry. Although there is ulceration and deformity of the lateral wall of the descending colon, the medial wall remains normal.

cosal tissue which appear somewhat different from the more rounded pseudopolyps (Fig 25).

Inflammatory strictures frequently develop in Crohn’s disease (Fig 26). The possibility of malignant stricture need rarely be considered because there is only a slightly increased incidence of carcinoma with Crohn’s disease.2

Fistulae and abscesses are frequent features of Crohn’s dis- ease.25 While these may be shown on double contrast studies, they are generally more easily demonstrated with the single contrast enema.2 Therefore, when a study is done primarily to demonstrate a fistula, we usually prefer the single contrast method (Fig 27).

POLYPOID LESIONS

Polypoid lesions in Crohn’s disease are similar or identical to those in ulcerative colitis. These include pseudopolyps due to ex- tensive ulceration, inflammatory polyps (Fig 281, and postin- flammatory polyps (Fig 29). As with ulcerative colitis, the post-

30

Fig 23.-Deep ulceration and fibrosis of the transverse colon. Even though the disease is circumferential, a greater length of bowel wall is involved inferiorly than superiorly, showing the asymmetric nature of Crohn’s disease.

infl;z;toye, polyps may be sessile, pedunculated, o; Neoplastic polyps are rare in Crohn s disease.

TERMINAL ILEUM

Crohn’s disease of the terminal ileum is present in the major- ity of patients with Crohn’s colitis.33 Changes in the terminal ileum include mucosal nodules (which must be differentiated from lymphoid hyperplasia) and typical aphthous ulcers (Fig 30). In more advanced disease, deeper ulceration, cobblestone mucosa, and strictures may be present (Fig 31). Because of re- gional lymph node involvement and thickening of the bowel wall and mesentery, a mass effect produced in the right lower quad- rant may cause compression of the medial wall of the cecum (Fis 32) and separation of involved loops of ileum from one another. In the patient with diffuse inflammatory disease involving the entire large bowel, the appearance of the terminal ileum may be the only way to differentiate Crohn’s disease from ulcerative col- itis.

REVERSIBILITY

The natural history of Crohn’s disease is recurrence and regression of clinical activity.25 Only rarely does the colon heal

31

Fig PI-Crohn’s colitis with “pseudodiverticula.” Sacculations are the result of asymmetric scarring in the descending colon.

32

Fig 25.-Severe Crohn’s disease producing a segment of cobblestone mucosa in the transverse colon.

Fig 26.-Crohn’s disease with inflammatory strictures of the transverse and de- scending colon and a pseudodiverticulum of the splenic flexure.

33

Fi g 27.- -Rectovaginal fistula complicating Crohn’s colitis is easily demonstr with single contrast enema using dilute barium.

34

- - Fig SIB-Active Crohn’s disease with inflammatory polyps in the splenic fle

Fig 29.--Quiescent Crohn’s colitis with linear scars and postinflammatory on a background of normal mucosa.

xure.

Polyps

35

Fig 30.-Aphthous ulcers (arrows) of the terminal ileum in Crohn’s disease.

Fig 31.-Deep, linear ulcers and cobblestone mucosa in the cecum and termin ileum of a IO-year-old boy with Crohn’s disease.

36

Fig 32.-Compression on medial wall of cecum by diseased terminal ileum and its affected mesentery.

completely with no radiologic evidence of scarring.2 There is lit- tle correlation between clinical response to therapy and evidence of radiologic improvement. Therefore, the ritual use of x-rays in observing patients is not recommended. After an initial exami- nation to establish the diagnosis, radiologic study is suggested only in the following circumstances: (1) when a severe clinical exacerbation occurs, to look for evidence of stricture with ob- struction or fistula; (2) for preoperative evaluation of patients undergoing planned resection; and (3) for evaluation of the postsurgical patient who develops symptoms of recurrence (Fig 33).33

SUMMARY The double contrast enema has been shown to be superior to

the conventional barium enema in detecting the presence of early inflammatory disease, in differentiating ulcerative colitis from Crohn’s colitis, and in determining the extent of involve- ment. The radiographic features of ulcerative colitis and granu- lomatous colitis are sufficiently characteristic to allow distinc- tion between them to be made in over 90% of cases. These features are summarized in Table 3 which combines the cases from two recent reports.

37

Fig 33.--Recurrent Crohn’s disease at the ileocolic anastomosis several months after resection of terminal ileum and proximal colon.

THE PRIMARY DOUBLE CONTRAST COLON EXAMINATION: OUR METHOD

In our institution we do both conventional barium enemas and double contrast enemas. The majority of examinations are by the double contrast technique. The guidelines used for determin- ing which method to choose are as follows:

A. Indications for double contrast enema: 1. Rectal bleeding-gross or occult. 2. Polyps or carcinoma-suspected or known. 3. Inflammatory bowel disease-suspected or known. 4. Patient 40 years of age or older who can cooperate and

turn over without assistance. B. Indications for single contrast enema:

1. Patient 40 years of age or younger not suspected to have polyps, colitis, or bleeding.

2. Patient unlikely to cooperate or retain enema. 3. Diverticulitis suspected. 4. Bowel not prepared but exam necessary anyway to ver-

ify or exclude obstruction, appendicitis, fistula, etc. 38

Most radiologists are aware that the double contrast enema has been repeatedly shown to be more sensitive than the single contrast enema for detectin B early inflammatory disease and small colonic neoplasms.‘* 2Y l7 34 However, some have been re- luctant to try the double contrast technique or have become frustrated and have abandoned it. Three major recurring com- plaints are heard. First, the procedure takes too long to perform, particularly in a high volume private practice. Second, they can- not consistently fill the cecum with barium for good mucosal coating. Third, x-rays cannot penetrate big puddles of high den- sity barium, and these puddles may obscure lesions. Our double contrast technique addresses these problems with some success.

MATERIALS

In the past we have used a number of different barium sulfate preparations. All were unsatisfactory for one reason or another. We now rely entirely on Liquid Polibar, which gives excellent results. This E-Z-EM Company product is a 100% W/V 65% W/ W) suspension of micronized barium sulfate that comes pre- mixed from the manufacturer. It has optimum density for the double contrast examination with a moderate viscosity. It is

TABLE Q.-RADIOLOGIC FINDINGS (1O3-co~s~cu~1v~ PATIENTS)*

RADIOLOGIC FINDINGS

ULCERATIVE CROHN’S COLITIS (52 ptdt COLITIS (51 pts.Yt

(2) (%I

Ulcerative colitis Specific

Granular Mucosa 81 - Diffuse rectal disease 81 -

Strongly suggestive Continuous, symmetric disease 90 16

Crohn’s colitis Specific

Discontinuous, asymmetric disease 2 84 Discrete ulcers on normal mucosa - Transverse stripes - (fi, Longitudinal fissures - (29) Deep ulcers (3 mm or more) - cm Right colon disease alone - (16)

Strong suggestive Terminal ileal disease Cobblestoning (34 (35:)

Nonspecific Findings Stricture (27) (63) Pseudopolyps (14) (8) Total colitis (14) (8)

*Combined data from Laufer & Hamilton’ and Kelvin et aL3 tData in parentheses is from Kelvin et a1.3 only (53 patients).

39

nonprecipitating, allowing additional patient evaluation up to one-half hour after beginning the study. The premixed suspen- sion is bubble free because it contains the proper amount of Si- methicone.

To make the double contrast enema easy to perform, the E-Z- EM Company has developed the Super XL Air Contrast System. Plastic tubing of one-half in. diameter is connected to the enema bag. This larger than normal lumen improves the flow of the relatively viscous Liquid Polibar. Attached to the other end of the tubing is a large bore, flexible Miller Air enema tip. The tip with an inflatable balloon cuff is used because the patient can more easily retain the tip while performing the many turning maneuvers required. The Miller Air tip with retention cuff con- tains three channels: a large, main channel for passage of bar- ium, a small channel for instilling air into the colon, and a third channel for inflation of the balloon cuff.

CONDUCTOFTHE EXAMINATION

Before the examination, 400 ml of Liquid Polibar are poured into the enema bag. The barium flows down the plastic tubing into the enema tip to expel air from the system and the tubing is clamped. The enema tip is inserted into the rectum with the patient on his left side. The enema bag is hung on an intrave- nous (IV) pole 3 feet above the table top.

40

STEPS

1. Place patient in the left anterior oblique (LAO) position. Tilt head of table down to - 15 degrees. Allow barium to flow. Inflate rectal balloon with one puff of air during fluoroscopic monitoring. When barium reaches distal transverse colon, turn it off (A). Add air slowly until sigmoid is filled with air (B).

-I

2. Roll patient into steep RAO position. Add air slowly until splenic flexure is filled with air.

41

3. Elevate head of table to + 15 degrees. Roll patient onto right side and then supine. If barium column is in ascending colon, proceed to Step 4; if not, jump to Modification #l.

4. Administer 1 mg of glucagon slowly IV if required to relieve large bowel spasm or patient discomfort. Most patients are not uncomfortable up to this point and do not need the glucagon earlier.

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5. Roll patient into left posterior oblique (LPO) position. Add air slowly until hepatic flexure is distended.

6. Elevate head of table to about + 75 degrees. Put enema bag on floor and open tubing to allow barium to drain from rectosig- moid. Take spot film of hepatic flexure.

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7. Rotate patient into right posterior oblique (RPO) position. Take spot film of splenic flexure. Clamp enema tubing and put enema bag on x-ray table. Lower table to horizontal (0) position.

8. Roll patient into steep LPO position. Add air slowly until ascending colon is distended. Lower head of table to - 10 de- grees.

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9. Roll patient supine and into RPO position. Take spot film of cecum. Return table to horizontal (0) position.

10. Roll patient toward left side and into prone position. Ele- vate head of table to +45 degrees. Place enema bag on floor. Open tubing to permit drainage of rectal barium. Depress enema tip between patient’s legs and add 5 puffs of air slowly to in- crease displacement of barium into the enema bag. Clamp enema tubing and put enema bag on x-ray table.

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11. Lower table to horizontal (0) position. Add air slowly until entire colon is well filled. Take oblique rectosigmoid spot films. - L--I- n-7

12. Take overhead films.

MODIFICATIONS

Our routine single stage technique is modified in two in- stances: (1) when the colon is particularly redundant and the head of the barium column does not reach the ascending colon after Step 3; and (2) when stool is identified in the large bowel. Modifications are inserted into the procedure just before the de- cision to use or not to use glucagon. This gives us the flexibility to carry out any necessary modifications before making the colon hypotonic.

Modification #l (To follow Step 3 if barium column is not in ascending colon.) A. Lower table to horizontal position. B. Rotate patient 360 degrees to the left (left side-prone-

right side-supine). C. If barium is in ascending colon, return to Step 4. D. If barium is not in ascending colon, rotate patient 360 de-

grees to the right (right side-prone-left side-supine). E. If barium is in ascending colon, return to Step 4; if not, go

to Modification #2.

Modification #2 (To follow modification #l or to be used if feces is encoun-

tered.) A. To enema bag, add one liter (1,000 ml) of thin barium (or-

dinarily used for conventional UGI series). B. Use thin barium as a plunger to push viscous barium into

ascending colon. 46

C. Deflate rectal balloon and remove enema tip. D. Assist patient to bathroom for evacuation. - E. Return patient within 5 minutes to x-ray table. F. Reinsert enema tip. G. Return to Step 4 of routine procedure.

OVERHEAD RADIOGRAPHS

Following conclusion of the initial phase of the examination by the radiologist, the radiologic technologist obtains overhead radiographs in various patient positions. Multiple views are re- quired to unfold the turns of the colon and to shift the locations of the barium pools so that obscured pathology will be revealed. We use the routine series of films recommended by Peterson and Miller.35 They concluded that a complete colon examination could be performed efficiently by using this “optimal” series of films, as presented below. All patient positions are described rel- ative to the x-ray table top.

1. PA view to include rectum-perpendicular central ray (Fig 34A).

2. Fifteen degrees RAO view of rectosigmoid with 35 degrees caudad central ray (Fig 34B).

3. Right lateral rectal view-10 x 12 in. film (Fig 340. 4. Twenty degrees RPO view to include splenic flexure and

descending colon (Fig 34D). 5. Forty-five degrees LPO view to include hepatic flexure and

ascending colon (after being in left lateral position where 10 pumps of additional air are given) (Fig 34E).

6. Fifteen degrees LPO view of rectosigmoid with 35 degrees cephalad central ray (Fig 34F).

7. Right lateral decubitus view to include rectum (Fig 34G). After 7, turn patient through the prone position to obtain 8.

8. Left lateral decubitus view to include rectum (Fig 34H). Before taking this film, deflate rectal balloon, add two pumps of air to rectum and remove enema tip.

PRINCIPLES FOR SUCCESS

Our step-by-step procedure describes many position changes for the patient and the x-ray table. The objective is to keep the column of barium always flowing “downhill,” speeded by the force of gravity. When the head of the barium column reaches the distal transverse colon, the tubing is clamped and a slow, almost continuous insufflation of air is begun. The air acts as a plunger for the barium while it simultaneously distends the bowel. The head of the barium column is always kept dependent to and ahead of the insufflated air until the barium reaches the

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Fig 34.~-Routine overhead radiographs. A, posterior-anterior view. B, right an- terior oblique angled view of rectosigmoid. C, right lateral rectum. D, right posterior oblique view to include flexures.

ascending colon. Thus, no “air lock’ prevents the barium from flowing into the cecum, which is rapidly coated with a small vol- ume of barium.

In addition to using a small volume of barium, we can further reduce the problem of opaque barium puddles by other means: Excess barium is drained from the rectosigmoid at two different times during the procedure. At least four films are taken with a horizontal x-ray beam reducing the puddle problem. These films are obtained with the patient in the upright and in both lateral decubitus positions.

The procedure used for double contrast examinations of the 48

Fig 34.-E, left posterior oblique view to include flexures. F, left posterior oblique angled view of rectosigmoid. G, right lateral decubitus view. H, left lateral decubitus view.

colon may initially appear too complicated. In our experience with first-year residents, this has not been the case. They learn this technique and obtain excellent quality studies after only one week of training. As a teaching aid, a written copy of the procedure is taped to the image intensifier housing so that it is available for ready reference.

Our technique requires no more fluoroscopic experience or time than a conventional barium enema. Fluoroscopy does not play the major role in detection of disease that it does with the conventional barium enema. Evaluation of the colon is per- formed largely on the films obtained. Fluoroscopy is used pri-

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marily: (1) to follow the progress of the barium column to the right side of the colon; (2) to assure that adequate distention of the colon with air is obtained; and (3) to position the patient for spot films.

CONCLUSION

My presentation has had three major objectives. First, to con- vincingly demonstrate the superiority of the double contrast enema over the conventional barium enema for evaluation of inflammatory bowel disease. Second, to review the characteristic double contrast features which distinguish ulcerative colitis from Crohn’s disease of the large bowel. And finally, to describe our technique for performing the double contrast enema, which we hope you will also find relatively simple and consistently ef- fective.

ACKNOWLEDGMENTS

Credit for the superb radiographs goes to technologists Caro- lyn German, Jerry Argenbright, Diane Jennings, and Debbie Towle, who taught our residents as much as I did. Drawings illustrating our technique were by C.A. Lute. The manuscript was prepared for publication by Pat West, Shirley Yowell, and Geneva ShiRlett. Thank you all.

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