double-contrast studies, the suture lines interrupt the mucosal folds where the segments were joined. Again over time, the fold pattern inside the pouch becomes less distinct.

The valve that allows the patient to remain continent is seen as an intussuscepted segment, 3 to 5 cm long and usually 2.5 to 4 cm in diameter, that protrudes into the reservoir. It is best seen in profile, utilizing a steep oblique or lateral projection. The valve should be examined while the patient is catheterized as well as after catheter removal. In the latter circumstance, films should be obtained both at rest and while the patient is straining.

The afferent limb is usually slightly greater in diameter than the more proximal ileum; it is otherwise indistinguishable from the rest of the ileum. The efferent limb is that short segment of small bowel that begins at the base of the continence-producing valve and transits the anterior abdominal wall to end at the stoma. This segment may make a large angle with the lumen of the valve when the patient is examined in the upright position. However, this may be normal.

Again, Lycke and colleagues have written a detailed analysis of the radiographic findings of complications of Kock pouches [112]. Abnormalities of the Kock pouch may be grouped according to the segment of the pouch that is affected by mechanical problems, recurrent inflammatory disease, or "pouchitis," a nonspecific inflammation of the reservoir.

Asymmetric loosening of the staples that help form the valve may lead to sliding, with a reduction of length along the mesenteric side of the valve. This can result in both incontinence and difficulty in catheter-ization. This loosening may eventually result in loosening of the antimesenteric side as well. This leads to a tortuous elongated efferent limb that actually replaces the valve.

If the opening in the inner aspect of the anterior abdominal wall enlarges, the base of the valve may become everted. Folding of the staple lines along the valve itself best depicts this [112]. With contrast studies, the efferent limb and valve take on an "ace of spades" configuration in either eversion or sliding.

Detachment of the reservoir from the anterior abdominal wall is difficult to detect and often overlooked on contrast studies [112]. A "cul-de-sac" in the efferent limb can be seen in cases of incomplete detachment [112].

Fistulae may be secondary to recurrent Crohn's disease or may be mechanical in origin. They may involve the walls of the valve itself; they may be between the afferent limb and the reservoir (internal fistula); or they may connect the reservoir to the skin (external fistula).

Recurrent Crohn's disease in the reservoir and/or afferent limb resembles that seen in preoperative patients. A cobblestoned mucosa may be seen along with areas of stenosis [112]. The reservoir may also be affected by nonspecific painful inflammation characterized by increased discharge of fluid and gas (Fig. 5.40). Double-contrast studies may reveal a granular mucosa in mild disease, which may progress to ulceration and edema in severe cases of ileitis or "pouchitis" [112].

Figure 5.40. Kock "pouchitis." (A) Retrograde "pouchgram" study shows the large saccular reservoir of a Kock pouch. Some of the contrast has refluxed into the afferent loop of ileum, which shows thickened folds consistent with ileitis. (B) Another film from the same study shows that the folds within the pouch itself are severely thickened and distorted, consistent with so-called pouchitis.

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