Detection of colorectal lesions with virtual computed tomographic colonography

Background: The aim of our study was to compare the performance of virtual computed tomographic colonography with that of conventional colonoscopy in a blinded, prospective study in 165 patients with suspected colorectal lesions. Methods: There were 165 patients, all referred for conventional colonoscopy, who underwent preliminary virtual computed tomographic colonography. Computed tomograhic images of all suspected lesions were analyzed and subsequently compared with conventional colonoscopy findings. Results: There were 30 colorectal cancers and 37 polyps identified at conventional colonoscopy. Virtual computed tomographic colonography correctly detected all cancers, as well as 11 of 12 polyps of 10 mm in diameter or larger (sensitivity, 92%); 14 of 17 polyps between 6 and 9 mm (sensitivity, 82%); and 4 of 8 polyps of 5 mm or smaller (sensitivity, 50%). The per-patient sensitivity and specificity were 92% and 97%, respectively. Conclusions: Virtual computed tomographic colonography has a diagnostic sensitivity similar to that of conventional colonoscopy for the detection of colorectal lesions larger than 6 mm in diameter.