http://www.ajronline.org/cgi/content/full/176/5/1105

Michael Macari and Emil J. Balthazar

¹ Department of Radiology, NYU Medical Center, Tisch Hospital, 560 First Ave., Ste. HW 207, New York, NY 10016. Received June 27, 2000; accepted after revision November 1, 2000.

CT has become the most important imaging technique for evaluating the abdomen and pelvis. CT is used to examine patients with acute abdominal complaints, known or suspected malignancy, abdominal and pelvic trauma, and inflammatory conditions. When CT images of the abdomen and pelvis are interpreted, the focus is often placed on the peritoneal cavity, the mesentery, and the parenchymal organs. A common misconception is that CT provides only limited information with respect to the gastrointestinal tract.

In fact, recent technologic advances and accumulated experience in image interpretation suggest that substantial information regarding gastrointestinal tract disorders can be obtained. Normal variants—as well as abnormal conditions—may cause thickening of the bowel wall. In this review, the normal CT appearance of the bowel wall and the different causes of bowel wall thickening will be described.

The various criteria that allow one to differentiate normal variants and abnormal conditions are reviewed, including attenuation pattern of bowel wall thickening; degree of bowel wall thickening; circumferential symmetric thickening versus asymmetric thickening; focal, segmental, or diffuse involvement; and associated perienteric abnormalities.