Virtual Colonoscopy - Still Limited Compared to Conventional Colonoscopy
December 13th, 2007 | by Mark Sapienza, M.D. |
Virtual Colonoscopy, also known as computed tomography colonography (CTC), is a newer diagnostic test used in the detection of colorectal tumors and polyps. The test involves a CT scan of the abdomen and pelvis performed by radiologists at an imaging center and relies on sophisticated computer modelling to render a three dimensional reconstruction of the inside of the colon. Compared to conventional colonoscopy (CC), the test does not require sedation and carries minimal risk of perforation of the colon. But the sensitivity and cost effectiveness of CTC as a screening test for colonic pathology is still being determined. When CC was compared to CTC in a recent study, CTC was found to be less sensitive in detecting polyps and lesions under < 10 mm in size. Flat lesions also could be missed by this screening test. For detection of lesions >/=10 mm the two tests were equivalent.
CTC is limited in that it is only a diagnostic test and any discovered polyps or lesions would require a follow-up colonoscopy with biopsy or polypectomy. As with all CT scans, the patient is also exposed to radiation when undergoing CTC. Despite it’s limitations CTC is a cost effective and useful screening test and may eventually evolve into a complementary colorectal screening test.
Reference: Arnesan RB, et al. Acta Radiol. 2007 Oct; 48(8):831-7.
Tags: Colon Cancer, Colon Polyps, Colonoscopy, Virtual Colonoscopy