Detection of occult colonic perforation before CT colonography after incomplete colonoscopy: Perforation rate and use of a low-dose diagnostic scan before CO₂ insufflation

OBJECTIVE. The purpose of this study was to obtain a low-dose CT scan before CT colonography to estimate the prevalence of occult colonic perforation among patients referred for same-day or next-day CT colonography after incomplete colonoscopy. MATERIALS AND METHODS. Two hundred sixty-two patients (74 men, 188 women; mean age, 64 years; range, 21-92 years) consecutively referred for same-day or next-day CT colonography after incomplete colonoscopy underwent low-dose diagnostic CT before rectal tube insertion and CO₂ insufflation. RESULTS. Perforation was found on the low-dose CT scans of two of the 262 patients (0.8%; 95% CI, 0.1-2.7%). One of these patients had no symptoms; the other had mild abdominal discomfort at the time of CT. CONCLUSION. The rate of occult colonic perforation after incomplete colonoscopy may be significant. For patients referred for CT colonography after incomplete endoscopy, use of low-dose diagnostic CT before rectal tube insertion and insufflation is indicated.