Anatomic factors predictive of incomplete colonoscopy based on findings at CT colonography

Reasons for failure to reach the cecum at optical colonoscopy are multifactorial. The purpose of this study was to compare CT colonography (CTC) findings in patients with complete versus those with incomplete optical colonoscopy.

The clinical data and CTC examinations were reviewed in 100 patients who underwent CTC after incomplete optical colonoscopy. The findings were compared with a control group of 100 patients who underwent complete optical colonoscopy after CTC. The interactive 3D colon map and 2D multiplanar reconstruction images from CTC were reviewed independently by two experienced gastrointestinal radiologists for colorectal length (total, sigmoid colon, and transverse colon), number of acute angle flexures (reflecting tortuosity), and advanced diverticular disease. Discrepancies were resolved by secondary consensus review.

Significant differences existed between the complete and incomplete optical colonoscopy groups, respectively, for age (mean, 58.2 vs 63.4 years; p < 0.001), sex (60 men and 40 women vs 41 men and 59 women; p < 0.01), and prior abdominal surgery (26.0% vs 48.0%; p < 0.01). Significant differences were seen between the complete and incomplete optical colonoscopy groups, respectively, for all the CTC factors that were evaluated: total colorectal length (mean, 167.0 vs 210.8 cm; p < 0.0001), sigmoid colon length (mean, 48.7 vs 66.8 cm; p < 0.0001), transverse colon length (mean, 49.2 vs 66.3 cm; p < 0.0001), number of flexures (mean, 9.6 vs 11.9; p < 0.0001), and advanced diverticular disease (22.0% vs 34.0%; p <0.05).

Anatomic features associated with failure to reach the cecum at optical colonoscopy included colonic elongation, tortuosity, and advanced diverticular disease. These predictive factors may have implications for optical colonoscopy training and performance and for patients sent to optical colonoscopy for polyps prospectively detected at CTC.