What is the advantage of a virtual colonoscopy?

When it comes to the individual patient, none. The government has hoped to find an inexpensive colon cancer screening technique that would be inexpensive, accurate, sensitive, and which would become widely accepted by the public. To this end, the government has funded research to find a "noninvasive" technique that could be used to screen large populations of people at risk for developing colorectal cancer so only a small number would need to go fort the "invasive" procedure of endoscopic colonoscopy. The virtual colonoscopy really does not fulfill this dream, given the human condition and the present state of the technology. Most people who undergo a colonoscopy usually don't mind the procedure itself; the requirement for a laxative bowel preparation prior to the examination deters the squeamish. The "virtual" examination does not eliminate this problem because it still requires a bowel preparation. The second problem is that most people undergoing standard bowel preparations in the typical American community (as opposed to those who are having the examination in a research setting at a university medical center) still have a small amount of fecal material in the colon which can confound the interpretation of the virtual examination much more than the interpretation of a directly visualized endoscopic colonoscopy. The radiologist cannot always tell the difference between a growth in the colon, fecal material in the colon, and a small growth covered by a layer of fecal material; the gastroenterologist merely turns on a water jet in the colonoscope to wash away any interfering fecal material. The virtual examination also is not very good for finding inflamed areas of the colon, superficial ulcerations, blood vessel abnormalities, and bleeding areas. These abnormalities are easily seen and treated under direct vision at standard colonoscopy. Finally, the radiologist has no ability to biopsy inflamed areas, to cauterize bleeding areas, or to remove polyps during the "noninvasive" examination. The disclaimer that patients with these findings can be sent immediately for the endoscopic examination is not realistic since the gastroenterologist could very well be occupied with a full endoscopic schedule at that time.