INTRODUCTION: Water-soluble contrast enema is routinely used to evaluate the status of pelvic anastomosis prior to closure of diverting stomas. Limited computerized axial tomography (CT) with rectal contrast may be a better option because of its ability to detect clinical or sub clinical abscesses, its requirement of less radiologic expertise and its better tolerance by patients. However, the sensitivity of CT with rectal contrast for detecting an anastomotic leak has not been prospectively evaluated. Our goal was to determine the value, efficacy and feasibility of a limited pelvic CT with rectal contrast for diagnosis of pelvic abscess with or without an anastomotic leak.METHODS: We conducted a prospective quality improvement study of 28 patients with proximal diverting stomas following low anterior resection with colorectal (n=7) and coloanal anastomosis (n=16) or total proctocolectomy with ileal pouch anal anastomosis (n=5). All patients underwent CT with rectal contrast prior to closure of diverting stoma. Scans were evaluated for the presence or absence of pelvic abscess and anastomotic leak. Closure of stoma was performed once there was no evidence of leak or abscess. Repeat studies were necessary when leak or abscess were present. A total of 56 CT scans with rectal contrast were performed. Patients were followed clinically for 6 months for signs of pelvic infection after closure of stoma.RESULTS: Of the 56 studies, 17 scans in 11 patients showed pelvic abscesses, and 43 showed no anastomotic leak. An anastomotic leak was demonstrated in 7 of 8 patients on the first CT and in one, on the subsequent CT evaluation. After closure of diverting stoma, no patient developed signs of pelvic infection. Sensitivity for detection of anastomotic leak on the first study was 100% (95% CI=76%, 100%) and specificity was 96% (95% CI=88%, 100%). Adverse effects included only mild discomfort during administration of rectal contrast but no significant complications occurred.CONCLUSIONS: These results suggest that pelvic CT scan with rectal contrast is a sensitive and safe study for detection of anastomotic leak following low pelvic anastomosis. Limited CT scan with rectal contrast represents a one-step diagnostic modality for detection of pelvic sepsis. We recommend that CT scan with rectal contrast may be considered as the study of choice when there is concern for pelvic abscess with or without anastomotic leak following low pelvic anastomosis in the preoperative planning for take down of proximal diverting ostomies.