Computed Tomographic Colonography (Virtual Colonoscopy): Blinded Prospective Comparison with Conventional Colonoscopy for the Detection of Colorectal Neoplasia

Background and Study Aims: Computed tomographic colonography (CTC), also known as virtual colonoscopy, is a recently introduced imaging modality for the detection of colorectal neoplasia. The aim of our study was to evaluate the performance of CTC in a blinded comparison with conventional colonoscopy.
Patients and Methods: A total of 66 consecutive, symptomatic patients underwent spiral computed tomography (CT) examination after standard bowel preparation. CT images were analyzed and subsequently compared with conventional colonoscopy findings.

Results: Conventional colonoscopy detected 15 colorectal carcinomas and 52 polyps. CTC correctly identified all carcinomas, 13 of 14 polyps greater than 10.0 mm (sensitivity 92.8 %; 95 % confidence interval (95 % CI); 77 - 100), 11 of 13 polyps between 6.0 and 9.0 mm (sensitivity 84.6 %; 95 % CI; 62 - 100), and six of 25 polyps smaller than 5.0 mm (sensitivity 24 %; 95 % CI; 6 - 42). The per-patient sensitivity and specificity were 93.7 % and 94.1 %, respectively.

Conclusions: Computed tomographic colonography is an accurate imaging modality for the detection of colorectal neoplasia, especially for lesions larger than 6.0 mm in diameter.

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