Virtual endoscopy--comparison with colonoscopy in the detection of space-occupying lesions of the colon

• Published in: Endoscopy Vol. 32; no. 3; p. 226
• Main Authors: Kay, C L, Kulling, D, Hawes, R H, Young, J W, Cotton, P B
• Format: Journal Article
• Language: English
• Published: Germany 01.03.2000
• Subjects: Adult; Aged; Aged, 80 and over; Colonic Neoplasms - diagnosis; Colonic Neoplasms - diagnostic imaging; Colonic Polyps - diagnosis; Colonic Polyps - diagnostic imaging; Colonoscopy - methods; Female; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Prospective Studies; Sensitivity and Specificity; Tomography, X-Ray Computed - methods
• ISSN: 0013-726X
• DOI: 10.1055/s-2000-100

A new technique has been described which combines abdominal helical computed tomography (CT) scanning and virtual reality computer technology, known as virtual colonoscopy (VC); the reconstructed images provide a simulation of the interior of the colon as viewed by endoscopy. We compared VC with conventional colonoscopy in patients with suspected or known colonic neoplasia. A total of 38 patients, in whom there was a high likelihood of colonic polyps or cancer, underwent a noncontrast helical CT scan of the abdomen and pelvis after regular colonoscopy bowel preparation. The images were reconstructed into a VC presentation and compared with the subsequent conventional colonoscopy in a blinded manner. Conventional colonoscopy identified a total of 24 polyps 5 mm or greater. VC correctly identified five of 13 polyps 5-9 mm in size, and ten of 11 lesions greater than or equal to 10 mm in diameter. The reasons for four missed lesions were identified as being secondary to a collapsed rectum in two patients and stool in the right colon in two patients. The sensitivity and specificity per patient of VC for lesions greater than or equal to 5 mm were 66.7% and 75.0% respectively, and for lesions greater than 1 cm were 90.0% and 82.1%, respectively. Virtual colonoscopy is feasible, well tolerated, and capable of detecting most lesions greater than 10 mm in diameter. This technique is continuing to be developed and warrants further evaluation as a diagnostic and screening tool in colorectal neoplasia.