CT Colonography (Virtual Colonoscopy)

What is this test?

Virtual colonoscopy, also called CT colonography, uses a CT scanner and specialized software to create detailed images of the large intestine. It can help identify polyps, abnormal growths, and other changes that may be associated with colorectal cancer.

Why might I need this test?

This test may be used to screen average-risk adults for colorectal cancer or to investigate symptoms such as blood in the stool, unexplained abdominal changes, or a change in bowel habits. It may also be considered for people who cannot or do not wish to undergo standard colonoscopy, depending on their medical situation.

How is the test performed?

For the examination, air is gently placed into the rectum and a CT scanner takes images of the abdomen and pelvis. The images are then reviewed on a computer. Unlike standard colonoscopy, virtual colonoscopy generally does not require sedation, although some patients may be given a medicine to help them relax.

How do I prepare for the test?

The colon must be thoroughly cleaned so that the images are not obscured by stool. Your imaging center will provide specific instructions about the bowel-preparation product, diet, and timing. Follow those instructions exactly and tell the care team about medications, allergies, pregnancy, kidney disease, or mobility limitations before the test.