Virtual Colonoscopy: Retrospective Comparison of the Findings in Supine and Prone Positions.

Background: Early detection of colorectal cancer (CRC) is significantly associated with reduced morbidity and mortality. Virtual colonoscopy (VC) is a minimally invasive, safe and well-tolerated alternative procedure to traditional colonoscopy. Therefore, we aimed to evaluate the findings of VC particularly in supine and prone positions as well as to contribute to the practical challenges of procedure.

Methods: Total number of 20 patients who underwent VC were included in this retrospective study. After proper bowel cleansing was achieved, intestinal dilatation was performed by injecting air into the rectum. Two different shots were performed in the supine and prone positions. Additionally, intestinal diameters were measured from the cecum to the rectum at their widest point via 2-dimensional coronal reformat.

Results: Polyps were detected in 3 patients which were confirmed by optical colonoscopy. The mean cecum diameter was detected as the largest diameter in the supine and prone examinations. In both supine and prone examinations, the distal descending colon was the most challenging site. Additionally, the mean descending colon diameter calculated in the prone position (40.9 ± 6.4 mm) was found to be statistically larger than descending colon diameter calculated in the supine position (36.1 ± 5.3 mm) ( = 0.001).

Conclusions: Our findings clearly demonstrated that combination of prone and supine scanning provides clear field of vision on narrow parts of the colon which improves accurate estimation for polyp detection. Furthermore, VC appears to be more comfortable, safe, fast, and cost-efffective procedure for CRC screening with advantages of low radiation exposure, extracolonic findings and lack of sedation requirements.