Computed Tomographic Colonography (Virtual Colonoscopy)
Journal - JAMA
Objective To assess the accuracy of CTC in a large numberof participants across multiple centers.Design, Setting, and Participants A nonrandomized, evaluator-blinded,noninferiority study design of 615 participants aged 50 yearsor older who were referred for routine, clinically indicatedcolonoscopy in 9 major hospital centers between April 17, 2000,and October 3, 2001. The CTC was performed by using multislicescanners immediately before standard colonoscopy; findings atcolonoscopy were reported before and after segmental unblindingto the CTC results.Main Outcome Measures The sensitivity and specificityof CTC and conventional colonoscopy in detecting participantswith lesions sized at least 6 mm. Secondary outcomes includeddetection of all lesions, detection of advanced lesions, possibletechnical confounders, participant preferences, and evidencefor increasing accuracy with experience.Results A total of 827 lesions were detected in 308 of600 participants who underwent both procedures; 104 participantshad lesions sized at least 6 mm. The sensitivity of CTC fordetecting participants with 1 or more lesions sized at least6 mm was 39.0% (95% confidence interval [CI], 29.6%-48.4%) andfor lesions sized at least 10 mm, it was 55.0% (95% CI, 39.9%-70.0%).These results were significantly lower than those for conventionalcolonoscopy, with sensitivities of 99.0% (95% CI, 97.1%->99.9%)and 100%, respectively. A total of 496 participants were withoutany lesion sized at least 6 mm. The specificity of CTC and conventionalcolonoscopy for detecting participants without any lesion sizedat least 6 mm was 90.5% (95% CI, 87.9%-93.1%) and 100%, respectively,and without lesions sized at least 10 mm, 96.0% (95% CI, 94.3%-97.6%)and 100%, respectively. Computed tomographic colonography missed2 of 8 cancers. The accuracy of CTC varied considerably betweencenters and did not improve as the study progressed. Participantsexpressed no clear preference for either technique.Conclusions Computed tomographic colonography by thesemethods is not yet ready for widespread clinical application.Techniques and training need to be improved.