The authors looked for studies published between 1975 and February 2005. They selected studies that reported CTC findings interpreted without knowledge of OC or surgery results. All patients in the studies had CTC after a full cleansing of the bowel, followed by either OC or surgery. Studies used a variety of techniques for CTC, including different types of scanners, different sizes of x-ray slices, and different computer software. The authors compared the sensitivity of CTC for detecting polyps of different sizes using OC or surgery as the reference standard.