[CT findings of non-traumatic colorectal perforation].

We retrospectively analyzed CT scans from 23 patients with non-traumatic colorectal perforation. We compared the sensitivity of CT and plain film radiography in the detection of free gas. Free gas was observed in 7 of the 23 cases (30.4%) on plain film radiography and 16 of the 23 cases (69.6%) on CT. Retroperitoneal abscess was demonstrated in 6 of the 7 patients without free gas on CT. Extraluminal air and abscess covered by the omentum and mesenterium were demonstrated in the remaining one patient. The site of perforation was identified in 19 of the 23 patients (82.6%) on CT. CT was useful for demonstrating retroperitoneal free gas, changes in mesenteric fat, extraluminal feces, and tumors. We conclude that CT is indicated in cases of suspected colorectal perforation.