Virtual colonoscopy can help patients avoid conventional colonoscopy

The significance of a detected colon polyp matches closely with the confidence score of an interpreting radiologist using virtual colonoscopy. This suggests that virtual colonoscopy may help determine if polyp removal is truly needed, thereby avoiding overuse of invasive conventional colonoscopy, according to a new study in the December 2004 issue of the American Journal of Roentgenology.

Virtual colonoscopy is a relatively noninvasive examination that uses a CT scan to evaluate the colon for polyps. “Among the benefits of virtual colonoscopy are that, unlike conventional colonoscopy, the procedure does not require intravenous pain medications, sedation or recovery room time,” said Perry J. Pickhardt, MD, from the University of Wisconsin Medical School and lead author on the paper.

For the study, 1,339 patients with no symptoms underwent both virtual colonoscopy and conventional colonoscopy. A total of 305 polyps were found at virtual colonoscopy that were 6 mm or larger, the size at which the physician needs to decide how to treat the patient. For those polyps, the likelihood that the polyp was found at conventional colonoscopy and that it was potentially precancerous correlated closely with the confidence score of the interpreting radiologist.

“Although conventional colonoscopy is an excellent test, it does carry a small but real risk for significant complications. While this risk is acceptable for patients with large polyps, it may outweigh the potential benefit for patients without large polyps, which comprise the vast majority of the asymptomatic screening population. In short, it seems prudent to reserve this more invasive procedure for those patients with a higher likelihood for harboring a significant polyp,” said Dr. Pickhardt.