About Virtual Colonoscopy
Virtual Colonoscopy is a procedure that makes use of computed tomography (CT) to examine the colon and rectum for presence of cancer or pre-cancerous polyps. Virtual colonoscopy can disclose tumors, bleeding, inflammatory bowel disease and diverticulosis.

Colorectal cancer, the second-leading cause of cancer-related deaths, is preventable in more than 90 percent of cases in which polyps are detected early. Despite that promising statistic, health officials estimate that 80 to 85 percent of people avoid screening, attributable partly to the discomfort of conventional optical colonoscopy. Unlike optical colonoscopy, virtual colonoscopy requires no sedation because it is a minimally invasive procedure.

Virtual colonoscopy eliminates the risk of perforating the colon while enabling enhanced detection of polyps as small as 3 millimeters (slightly less than one-eighth of an inch) in diameter. While conventional colonoscopy takes two hours or more to perform, virtual colonoscopy can be completed within half an hour and is a far more comfortable procedure.

Referral by a physician is required for virtual colonoscopy.

What to expect
The test requires rectal insertion of a narrow, flexible tube, through which air is pumped to expand the folds of the colon. For your examination, you will lie comfortably on your back on a padded table that will move in short steps through the scanner as an CT tube rotates around you. At each step, the scanner completes a separate view. The information is processed by the computer and displayed as three-dimensional images on a video screen for the technologist.

You should remain as still as possible to produce the clearest images. You will be asked to hold your breath for up to 30 seconds.

The procedure typically requires about 30 minutes.

Patient preparation
Just as for conventional colonoscopy, you must follow a bowel-emptying regimen the day before the examination to enable clear imaging of tissues. You will be placed on a liquid diet and prescribed laxatives to eliminate all solid material from your colon.

Tell your physician and the technologist if you think you may be pregnant. If you have diabetes, ask your physician about decreasing your insulin dosage while fasting. You will be asked to wear a gown during the procedure. Further preparations are described in an instruction sheet given to patients.

Side effects and complications
Patients may experience intestinal gas and cramping. No complications are associated with virtual colonoscopy.

Follow-up care
The virtual colonoscopy exam itself requires no follow-up care.