Colorectal neoplasia: Performance characteristics of CT colonography for detection in 300 patients

PURPOSE: To determine the sensitivity and specificity of computed tomograph ic (CT) colonography for colorectal polyp and cancer detection by using col onoscopy as the reference standard. MATERIALS AND METHODS: Three hundred patients underwent CT colonography fol lowed by standard colonoscopy. Bower preparation consisted of magnesium cit rate and polyethylene glycol. After colonic air insufflation, patients unde rwent scanning in the supine and prone positions with 3-mm collimation duri ng a single breath hold. The transverse CT images, sagittal and coronal ref ormations, and three-dimensional endoluminal images were interpreted by two radiologists independently, and then a consensus reading was performed. CT colonographic findings were correlated with standard colonoscopic and hist ologic findings. RESULTS: The overall sensitivity and specificity of CT colonography for pol yp detection were 90.1% (164 of 182) and 72.0% (85 of 118), respectively. B y using direct polyp matching, the overall sensitivity was 69.7% (365 of 52 4). The sensitivity was 90% (74 of 82) for the detection of polyps 10 mm or larger, 80.1% (113 of 141) for polyps 5.0-9.9 mm, and 59.1% (178 of 301)fo r polyps smaller than 5 mm. The sensitivity was 94% (64 of 68) for the dete ction of adenomas 10 mm or larger, 82% (72 of 88) for adenomas 5.0-9.9 mm, and 66.9% (95 of 142) for adenomas smaller than 5 mm. CT colonography was u sed to identify all eight carcinomas. CONCLUSION: CT colonography has excellent sensitivity for the detection of clinically important colorectal polyps and cancer.