The barium enema diagnosis of paracolic abscess.

The barium enema diagnosis of 38 cases of paracolic abscess is discussed. The importance of an appreciation of the anatomy of the peritoneum and of the paracolic region is emphasized. Five features of paracolic abscess that can be recognised on double contrast barium enema examination are analysed. These are soft tissue mass; extraluminal gas collection; barium-filled cavitation; displacement, impression or narrowing of the lumen; and mucosal changes. The commonest feature, present in 95% of cases, is displacement or impression or narrowing of the bowel lumen. An analysis according to site and aetiology is presented and the commonest causes found to be diverticulitis and appendicitis. The differential diagnosis is discussed, and differentiation from primary colonic carcinoma, metastases, Crohn's disease, ischaemia and endometriosis is described.