DIAGNOSIS AND DIFFERENTIAL-DIAGNOSIS OF ULCERATIVE-COLITIS AND CROHNS-DISEASE BY HYDROCOLONIC SONOGRAPHY

Objectives:The entire length of the colon, starting at the rectosigmoi d junction and ending at the cecum, can be visualized by transabdomina l sonography after retrograde water instillation into the colon. By th is method, termed hydrocolonic sonography, it is possible to evaluate in detail the lumen, the colon wall, and the surrounding tissue. Five layers of different echogenicity can be differentiated within the colo n wall. Methods:In a prospective study of 440 patients, we compared th e value of conventional abdominal sonography and hydrocolonic sonograp hy with that of colonoscopy, in the diagnosis and differential diagnos is of ulcerative colitis and colonic Crohn's disease. Results: In 93% of patients with Crohn's disease, the normal five-layer structure of t he colonic wall was no longer in evidence, and the wall appeared hypoe chogenic and clearly thickened. In contrast, in patients with ulcerati ve colitis, the five-layer structure could clearly be discerned, and a lthough the colon wall remained hypoechogenic, it was only moderately thickened. Colonic Crohn's disease and ulcerative colitis were detecta ble by hydrocolonic sonography, with a sensitivity of 96% and 91%, res pectively, whereas the sensitivity achieved by conventional abdominal sonography was only 71% and 62%, respectively. Furthermore, hydrocolon ic sonography made possible the differentiation of Crohn's disease fro m ulcerative colitis in 93% of the cases. Conclusion: This new diagnos tic procedure could thus advantageously be introduced for the diagnosi s, differential diagnosis, and follow-up of patients with chronic infl ammatory large bowel diseases.