Virtual colonoscopy

If a colonoscopy did not give clear enough pictures, you may have a virtual colonoscopy.

In a virtual colonoscopy, a CT scanner takes a series of x-rays. This builds up a three-dimensional (3D) picture of your bowel. You have this scan in the hospital CT department as an outpatient. The person doing the scan is usually a radiographer.

Your bowel must be completely empty for a virtual colonoscopy. You will need to follow a special diet for a few days and take a laxative before the scan. Your healthcare team  will tell you what to do.

The radiographer may give you an injection to help the muscles in your bowel relax. You may also have an injection of a dye at the same time. This is called a contrast medium. The radiographer will tell you if you are going to have this.

Just before the scan, the radiographer passes a tube into your rectum and pumps in some air or gas (carbon dioxide). This expands the bowel and helps to give a clearer picture. You will have 2 CT scans – 1 lying on your back and 1 lying on your front.