title: Virtual endoscopy--comparison with colonoscopy in the detection of space-occupying lesions of the colon.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Radiology, Digestive Disease Center, Medical University of South Carolina, Charleston, USA. kaycl44@hotmail.com
authors.forename: C L
authors.initials: CL
authors.lastname: Kay
authors.forename: D
authors.initials: D
authors.lastname: Kulling
authors.forename: R H
authors.initials: RH
authors.lastname: Hawes
authors.forename: J W
authors.initials: JW
authors.lastname: Young
authors.forename: P B
authors.initials: PB
authors.lastname: Cotton
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003111:Colonic Polyps / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003113:Colonoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*