Validation Of Virtual Colonoscopy In The Detection Of Colorectal Polyps And Masses Rationale For Proper Study Design Benoit C. Pineau,* ,1,2 Electra D. Paskett, 2 G. John Chen, 3 Valerie L. Durkalski, 6 Mark A. Espeland, 4 and David J. Vining 5 1 Department of Internal Medicine, Section of Gastroenterology, 2 Department of Public Health Sciences, Section of Epidemiology, 3 Department of Public Health Sciences, Section of Health Services Research, 4 Department of Public Health Sciences, Section of Biostatistics, 5 Department of Radiology, Section of Abdominal Imaging, Wake Forest University School of Medicine, Winston-Salem, NC, and 6 Department of Biometrics, Medical University of South Carolina, Charleston, SC Abstract Background: Colorectal cancer, the second-leading cause of cancer-related mortality, is a preventable malignancy in many cases. Despite the availability of several screening modalities, compliance with screen- ing recommendations remains unacceptably low. Virtual colonoscopy is a novel, minimally-invasive tech- nique with the potential to increase colorectal cancer screening rates, but its effectiveness must first be validated. Published studies comparing virtual colonoscopy to conventional colonoscopy have reported vary- ing results. These discrepancies may be attributed to differences in bowel preparation and scanning tech- niques, as well as errors in endoscopic lesion measurement, endoscopic colonic segmental localization, and the ability of conventional colonoscopy to actually detect lesions. These methodological issues can affect scientific results and ultimately affect the public’s perception of this emerging technique. Aim: The goal of this report is to expose existing methodological shortcomings and propose solutions incorporated in this study design. This article describes the rationale, study design, and outcome definitions of a single-center, blinded, direct comparative trial aiming at assessing the ability of virtual colonoscopy to detect colorectal polyps and masses relative to the criterion standard, conventional colonoscopy. Design Features: Bowel preparation was standardized using oral sodium phosphate lavage, orally admin- istered iodinated contrast, and controlled colonic insufflation. Segmental unblinding allowed a second-look when results were discrepant and polyp matching was performed using an algorithm based on segmental localization and lesion size determination. Conclusions: This methodology could be applied to other studies assessing the accuracy of virtual colonoscopy in order to have uniformity of results. Key Words: Virtual colonoscopy; study design; polyp matching; clinical trial. Introduction Colorectal carcinoma is a disease of significant public health concern. In the United States, the colon and rectum are projected to rank fourth in leading sites for new cancer development, and second only International Journal of Gastrointestinal Cancer, vol. 30, no. 3, 133–140, 2001 © Copyright 2001 by Humana Press Inc. All rights of any nature whatsoever reserved. 0169-4197/01/30:133–140/$20.00 133 *Author to whom all correspondence and reprint requests should be addressed: Benoit C. Pineau, M.D., M.Sc.(Epid.), F.R.C.P.C.,Assistant Professor of Medicine and Epidemiology, Department of Internal Medicine, Section of Gastroenterology, Wake Forest University School of Medicine, 2 Medical Center Boulevard, Winston-Salem, NC 27157. Tel: (336) 716-4621, Fax: (336) 716-6376. E-mail: bpineau@wfubmc.edu Research Article