CT Colonography (Virtual Colonoscopy)

What is CT Colonography?

CT scanning is a noninvasive, painless medical test that helps physicians diagnose and treat medical conditions. CT Colonography uses CT scanning to obtain an interior view of the colon (the large intestine) that is ordinarily only seen with an endoscope inserted into the rectum.

What are some common uses of the procedure?

The major reason for performing CT Colonography is to screen for polyps and other lesions in the large intestine. Polyps are benign growths that arise from the inner lining of the intestine. Some polyps may grow and turn into cancers.

The goal of screening with Colonography is to find these growths in their early stages, so that they can be removed before cancer has had a chance to develop. Most physicians agree that everyone older than 50 years should be screened for polyps every seven to 10 years. Individuals at increased risk should be screened every five years. Risk factors for the disease include a history of polyps, a family history of colon cancer, or the presence of blood in the stool.

How should I prepare for the procedure?

You should wear comfortable, loose-fitting clothing to your exam. You may be given a gown to wear during the procedure.

Metal objects including jewelry, eyeglasses, dentures and hairpins may affect the CT images and should be left at home or removed prior to your exam. You may also be asked to remove hearing aids and removable dental work.

Women should always inform their physician or technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.

It is very important to clean out your bowel the night before your CT Colonography examination so that the radiologist can clearly see any polyps that might be present. You will be asked to take a cathartic liquid, Fleet Prep Kit 1 (phospho-soda and Bisacodyl)

Be sure to inform your physician if you have heart, liver or kidney disease to be certain that the bowel prep will be safe. On the day before your exam, you should limit your food intake to clear liquids such as broth, tea or juice. You will be able to resume your usual diet immediately after the exam.