CT colonography



In some patients who are not keen to have a colonoscopy or had an incomplete colonoscopy a CT colonography may be used as an alternative test.


CT colonography is used to examine the large bowel (colon and rectum), and detect abnormalities such as polyps and cancer. Polyps are growths in the lining of the colon or rectum that protrude into the intestinal canal (link).



CT colonography is less invasive than a conventional colonoscopy. It involves using a CT scanner to produce 2- and 3-dimensional images of the entire colon and rectum. The negative aspect of the test is the radiation dose (and that if the test identifies a polyp, then you will require a colonoscopy.


CT colonography is performed on an empty bowel. Sedation is not usually required. The colon is distended by insufflation (blowing in air) with air or carbon dioxide, via a small rectal tube. The CT scan is done with the patient holding his or her breath for approximately 20 seconds in two positions. The images are then manipulated and interpreted by a radiologist. Results will be sent to GP or explained at next apointment