Virtual CT colonoscopy without bowel cleansing: Initial experiences

Introduction: The thorough cleansing of the colon is usually a prerequisit of virtual colonoscopy similarly to conventional colonoscopy. Nevertheless, the cleansing may be one of the main causes of patient inconviniency. We evaluated the possibility of prepartionless virtual CT colonoscopy in patients with colonic pathologies.

Materials and methods: 14 patients with colonic polyps, tumors and strictures undervent preparationless CT colonography. The patients had no food restrictions in the days before the examination, only 6 times 20ml of radiologic contrast material vas administered orally 48 hours prior to the examination. No colonic cleansing was used. The colon was distended by rectal air insufflation on the CT table until patient tolerance. Then thin slice spiral (or multislice) native CT images were evaluated using an own developed software (ColVis) and virtual endoscopic videos were generated. All the patients had conventional colonoscopy within a week for reference.

Results: 3 of the 3 tumors, 4 of the 4 polyps >10mm, 7 of the 10 polyps <10mm were correctly detected by CT colonography. Polyps smaller than 5mm were difficult to differentiate from tagged stool on the 2D images. The colon above severe strictures was well depicted in 2/2 cases. Electronic elimination of the tagged stool resulted smooth virtual endoscopic images and depicted polyps >5mm well.

Conclusion: Virtual colonoscopy without colonic cleansing minimizes patients discomfort before the examination. Electronic cleansing of the tagged stool is feasible. The method has promising initial results for detecting cancers and larger polyps.