Computerized tomographic colonography: performance evaluation in a retrospective multicenter setting1 1Vital Images Inc. has supported research at UCLA (to D. S. K. L., J. A. B., and E. G. M.). Monex provided support (to M. M.). GE Medical Systems provided software license and research support (to C. D. J., J. A. B., and A. H. D.). Voxar, Inc. produces products that compete with products listed in this paper (to M. A. B.).The study design was approved by the National Cancer Institute Cancer Therapy Evaluation Program. Computerized tomographic colonography examinations for American College of Radiology Imaging Network Protocol A6656 were submitted by E. G. McFarland, Mallinckrodt Institute of Radiology, St. Louis, Missouri; M. Zalis, Massachusetts General Hospital, Boston, Massachusetts; C. D. Johnson, Mayo Clinic, Rochester, Minnesota; M. Macari, New York University, New York, New York; D. Lu, University of California, Los Angeles, California; A. H. Dachman, University of Chicago, Chicago, Illinois; M. Morrin, Beth Israel/Deaconess Hospitals, Boston, Massachusetts; and J. Yee, Veterans Administration Hospital, San Francisco, California. Workstations for performing computerized tomographic colonography interpretations were loaned to the American College of Radiology (ACR) by General Electric, Vital Images, and the Mayo Clinic. Each provided technical support for installation at the ACR. Computerized tomographic colonography examinations were removed and workstations returned after the study interpretations were completed

Background & Aims: No multicenter study has been reported evaluating the performance and interobserver variability of computerized tomographic colonography. The aim of this study was to assess the accuracy of computerized tomographic colonography for detecting clinically important colorectal neoplasia (polyps ≥10 mm in diameter) in a multi-institutional study. Methods: A retrospective study was developed from 341 patients who had computerized tomographic colonography and colonoscopy among 8 medical centers. Colonoscopy and pathology reports provided the standard. A random sample of 117 patients, stratified by criterion standard, was requested. Ninety-three patients were included (47% with polyps ≥10 mm; mean age, 62 years; 56% men; 84% white; 40% reported colorectal symptoms; 74% at increased risk for colorectal cancer). Eighteen radiologists blinded to the criterion standard interpreted computerized tomography colonography examinations, each using 2 of 3 different software display platforms. Results: The average area under the receiver operating characteristic curve for identifying patients with at least 1 lesion ≥10 mm was 0.80 (95% lower confidence bound, 0.74). The average sensitivity and specificity were 75% (95% lower confidence bound, 68%) and 73% (95% lower confidence bound, 66%), respectively. Per-polyp sensitivity was 75%. A trend was observed for better performance with more observer experience. There was no difference in performance across software display platforms. Conclusions: Computerized tomographic colonography performance compared favorably with reported performance of fecal occult blood testing, flexible sigmoidoscopy, and barium enema. A prospective study evaluating the performance of computerized tomography colonography in a screening population is indicated.