Intestinal malrotation can be diagnosed on CT by the anatomic location of a right-sided small bowel, left-sided colon, an abnormal relationship of the superior mesenteric vessels, and aplasia of the uncinate process. Awareness of these abnormalities is necessary to diagnose this anomaly. It should be sought in patients with a situs problem, inferior vena cava anomalies, polysplenia, or preduodenal portal vein. Although usually an incidental finding, it is important to diagnose such a malrotation because it may cause abdominal symptoms. Also, knowledge of associated vascular anomalies is important when abdominal surgery is planned.

Retroperitoneal perforation during endoscopic sphincterotomy is a rare complication, which occurred in 1.13% of our patients. It can be usually clearly recognized radiographically by an abdominal film and in doubtful cases by CT. We emphasize the importance of recognizing this potentially serious complication with imaging studies.

The diagnosis of colorectal perforation can be made on CT. Because the diagnosis is not always suspected by the clinician, the radiologist may be the first to suggest it. Therefore, the radiologist should be familiar with the CT features of a potentially lethal, rectally induced perforation.