Abdominal CT findings in nontraumatic colorectal perforation.

Colorectal perforation is an emergent medical condition in which the diagnosis and the etiology are often established on CT, the common imaging modality used for evaluating the acute abdomen. The cardinal, direct CT features suggesting perforation are extraluminal air and enteric contrast, added by secondary signs of bowel pathology, such as focal bowel wall thickening and bowel wall defect. This pictorial review will illustrate the CT findings of colorectal perforation caused by various clinical entities.