According to a study CT colonography (CTC) helps radiologists to predict, with a high degree of confidence, whether or not a polyp needs to be evaluated through colonoscopy or removed through polypectomy. The study lead by author Steven M. Wise, MD, from the University of Wisconsin School of Medicine and Public Health in Madison, Wis. evaluated 479 patients with 739 CTC detected lesions The researchers reported that their study results showed that 91.6 percent detected on CTC were also found during optical colonoscopy or surgery. Wise and colleagues found that increased diagnostic confidence and a polypoid (nonflat) morphology correlate with a higher likelihood of finding a matching lesion at optical colonoscopy. Polyp size alone (6-9 mm vs. equal to 10 mm) had little effect on positive predictive value, being greater than 90 percent for both size categories. Wise said that the finding that the vast majority of polyps found on CTC do represent true polyps will help better establish CTC as a first line screening test for colon cancer in clinical practice.