What are the relative advantages of conventional colonoscopy and virtual colonoscopy?

The most common means of screening for colon cancer is conventional colonoscopy, which involves threading a fiberoptic scope into the large bowel. This procedure is typically performed under sedation, requiring a recovery period. The bowel lining is directly visualized with a tiny optical camera. If polyps are found, they can be removed at the time of the procedure. The procedure has been considered the “gold standard” for colon cancer screening for a number of years. It is highly accurate and quite safe. The patient must thoroughly cleanse their bowel prior to the examination. This is called a bowel “prep.” There is a low incidence of complications associated with colonoscopy, including perforation of the colon wall. This is a rare occurrence, but can have serious consequences when it occurs.

CT colonoscopy (virtual colonoscopy) is a new technique for inspecting the wall of the colon. It is still under investigation and is not yet considered to be a standard screening test. Early clinical studies indicate that it is an accurate and safe technique when used to detect colon cancer and polyps at an early stage of development. The “prep” for virtual colonoscopy is the same as for conventional colonoscopy. Virtual colonoscopy has the advantage of allowing your doctors to see the lining of the colon without inserting a fiberoptic scope into the large bowel. This eliminates any risks and complications associated with conventional colonoscopy. The examination is typically performed without the use of sedation, therefore, patients are able to resume their normal activity after the examination. Since there is no endoscope employed, polyps identified on virtual colonoscopy cannot be removed at the time of the examination and the patient will require a conventional colonoscopy for removal of any polyps identified on the virtual colonoscopy examination.