A colonoscopy is traditionally a rather nasty investigation of the colon for polyps - fleshy intrusions from the walls of the lower intestine, passing over the digestive tract. These can be harmless, or they can be cancerous growths. The only traditional way to tell is to take a fibre optic sensor and a long waterproof glove, and explore rectally.

Hardly the most pleasant experience.

Virtual colonography on the other hand, is a relatively new field, which is completely non-invasive. A computed Topography (CT) scan is taken, where the body is invasively scanned into slices, which are then reconstituted into a 3D model of a person's insides.

The 3D model of the rectal area can then be flit through from any angle, and the growths in colon walls examined without physical constraints getting in the way, under any light conditions.

It sounds like a fantastic advancement, but virtual colonoscopy has been plagued by fears that it is unable to properly diagnose polyps due to the large number of benign - and thus unnecessary - surgically removed polyps the process has resulted in.

However, like anything else, it has taken time for virtual colonoscopy techniques to be refined, and the visualisation fully understood.

The American College of Radiology Imaging Network (ACRIN)finally released a study in September 2008, based on clinical trials involving more than 2600 patients at 15 sites across the USA. Their published results have found that virtual colonography is in fact highly accurate for detecting intermediate and large sized polyps.

Accuracy was found to be comparable to conventional colonoscopy across a variety of clinical settings. More convenient, less invasive and preferred by patients, with comparable medical results to standard colonoscopy, perhaps there will be far fewer painful medical exams involving latex gloves and rear ends, thanks to a VR procedure that is proving its worth.

References

ACRIN PROTOCOL 6664

Accuracy of CT Colonography for Detection of Large Adenomas and Cancers