Automated carbon dioxide insufflation for CT colonography: effectiveness of colonic distention in cancer patients with severe luminal narrowing.

OBJECTIVE: The objective of our study was to determine the effectiveness of automated CO2 insufflation in colonic distention for CT colonography (CTC) in patients with severe luminal narrowing by colorectal cancer and preliminarily evaluate its safety performed shortly after colonoscopic polypectomy or biopsy.
MATERIALS AND METHODS: Seventy-four patients were examined with colonoscopy and subsequent CTC (time interval, 0-8 days) using automated CO2 insufflation. Thirty-six patients whose colonoscopy was incomplete due to severe luminal narrowing by cancer that prevented colonoscope passage constituted the stenotic group. The remaining 38 patients constituted the nonstenotic group. Colonic distention was graded by two experienced readers from 1 (worst) to 4 (best) and compared between the two groups. Clinical data and CT images were analyzed for the occurrence of colonic perforation.
RESULTS: Distention was not significantly different between the stenotic and nonstenotic groups in any colonic segments in both supine and prone positions. The mean distention grade +/- SD of the colonic segments proximal to the luminal narrowing in the stenotic group (n = 143 segments) was 3.7 +/- 0.7 and 3.8 +/- 0.7 for the supine and prone positions, respectively. Colonic perforation was not noted in any of the 74 patients, including 65 patients who underwent CTC within 24 hours after colonoscopy (62 snare polypectomies, two polypectomies using biopsy forceps, 63 routine mucosal biopsies).
CONCLUSION: Automated pressure-controlled CO2 insufflation is as efficient in colonic distention for CTC in colorectal cancer patients with severe luminal narrowing as it is in patients without severe luminal narrowing.