CT diagnosis of closed loop obstruction.

A case of closed loop obstruction presenting with unremarkable plain abdominal films and diagnosed by CT is reported. The presence of (a) fluid filled distended small bowel loops; (b) abrupt transition with collapsed distal intestinal loops; and (c) grossly distended fluid filled "U" shaped loop are diagnostic of this entity. Prompt CT recognition, before signs of intestinal gangrene develop, will lead to immediate surgical decompression and a significant decrease in the morbidity and mortality of this potential abdominal catastrophe.