Virtual colonoscopy is another procedure used to look for colon conditions including pre-cancerous growths, called polyps, and colorectal cancer. Images of the large intestine are taken using computerized tomography or, less often, magnetic resonance imaging. A computer puts the images together to create an animated, three-dimensional view of the inside of the large intestine.
Before a virtual colonoscopy, all solids must be emptied from the gastrointestinal tract by following a clear liquid diet for one to three days before the procedure. Unlike traditional colonoscopy or sigmoidoscopy, virtual colonoscopy does not involve the insertion of a colonoscope or sigmoidoscope into the anus. However, a small, catheter-like tube is inserted into the anus. Air is pumped through this tube into the large intestine to give the provider a better view of the colon.
Virtual colonoscopy does not require sedation. However, the provider is not able to remove polyps or suspicious tissue for biopsy during a virtual colonoscopy because no scope is inserted into the colon.