Intended for healthcare professionals

Clinical Review Science, medicine, and the future

Virtual colonoscopy

BMJ 1999; 319 doi: (Published 06 November 1999) Cite this as: BMJ 1999;319:1249
  1. Steve Halligan, consultant radiologist (,
  2. Helen M Fenlon, consultant radiologistb
  1. a Intestinal Imaging Centre, St Mark's Hospital, Harrow HA1 3UJ
  2. b Department of Radiology, Mater Misericordiae Hospital, Dublin, Republic of Ireland
  1. Correspondence to: S Halligan

    Editorial by Atkin

    Virtual colonoscopy is a new procedure that fuses computed tomography of the large bowel with advanced techniques for rendering three dimensional images to produce views of the colonic mucosa similar to those obtained during “real” colonoscopy. Preliminary results suggest that it surpasses barium enema and approaches the sensitivity of conventional colonoscopy. This review summarises the technical developments that have made virtual colonoscopy possible and describes the expected advantages of this exciting technique over conventional endoscopy and more traditional imaging methods. We describe its possible applications and outline further technical developments that can be expected in the near future.


    In 1994 the Royal Mail issued a series of four stamps celebrating major medical advances of the 20th century; three of these were radiological (ultrasound scanning, computed tomography, and magnetic resonance imaging). Radiology is a technology based discipline and is one of the most rapidly developing medical specialties, not least because advances in computer technology are almost instantly incorporated into the various imaging modalities. Image acquisition and display are constantly improving, and image processing that required until recently a dedicated workstation is now possible with a personal computer. The possibilities for diagnostic imaging that are available today would have been unimaginable only 30 years ago, and computed tomography has played a central role in this development.

    Predicted developments

    New multi-slice spiral computed tomography will increase the sensitivity of virtual colonoscopy for detecting colorectal polyps

    Faster and cheaper computer power will translate into faster and more complex image reconstruction, such as “virtual pathology”

    Image analysis and polyp detection are likely to become automated

    Oral labelling agents will eliminate the need for bowel cleansing

    Magnetic resonance imaging will be increasingly used for virtual examinations

    Because virtual colonoscopy is safe, easy, complete, and, once bowel cleansing is eliminated, non-invasive, it will assume a prominent …

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