Air contrast studies of the colon in inflammatory bowel disease.

The purpose of this review is to evaluate the role of double-contrast examination of the colon, in the detection and differential diagnosis of colitis. The emphasis is on correlation with endoscopy, (twelve color endoscopic photographs are included with the corresponding radiographs illustrating the spectrum of abnormalities in ulcerative and granulomatous colitis), differential diagnosis between ulcerative and granulomatous colitis (the double-contrast technique allows for accurate examination of the rectum and careful mapping of the extent and nature of disease in an involved segment. This facilitates the differential diagnosis between ulcerative and granulomatous colitis), and detection of early changes (in ulcerative colitis, the early stage of mucosal edema results in a finely granular mucosa on double-contrast study. In granulomatous colitis, small, shallow, "aphthoid" ulcers are frequently seen as the earliest lesion). The accuracy of the double-contrast technique is assessed by review of series comparing the radiologic and endoscopic findings. This is compared to the accuracy of the conventional enema. Some of the important technical considerations necessary for good double-contrast studies are discussed, as well as some of the potential pitfalls in interpretation.