(Computed Tomography Colonography; Virtual Colonoscopy)
CT colonography is a radiology test that looks at your large intestines (colon). It is one of many options for colon cancer
Reasons for Test
This test is used to look for polyps
CT colonography is safe. It can be used if you are too sick to undergo other forms of colon cancer screening.
In some cases, a contrast material is used. One complication may be an allergic reaction to the contrast.
What to Expect
Prior to Test
- Do not eat for 8-12 hours before the test.
- A bowel cleansing will be done with a laxative. The goal of the cleansing is to rid your colon of all stool. The laxative will cause you to have many bowel movements over several hours.
- If you have diabetes, talk to your doctor about adjusting your medicines.
Description of the Test
A radiologist will position you on your back on a movable x-ray table. Just before the test, a small tube will be inserted into your rectum. Air will be gently pumped through this tube. The table will move slowly though the donut-shaped CT scanner. While this is happening, you will need to lie very still. You will be asked to hold your breath during the scan. The scanning test will then be repeated with you lying on your stomach.
You will be able to leave after the test is done. You can resume your normal diet and activities.
How Long Will It Take?
Will It Hurt?
You may feel cramping and bloating. You may feel the urge to have a bowel movement.
An expert will review the images. If something abnormal is seen, your doctor may suggest a
American College of Gastroenterology
National Digestive Diseases Information Clearinghouse
Canadian Association of Gastroenterology
Canadian Cancer Society
Fletcher RH. Colorectal cancer screening on stronger footing. NEJM. 2008;359:1285-1287.
Gore RM, Levine MS. Textbook of Gastrointestinal Radiology. 2nd ed. Philadelphia: WB Saunders Company; 2000.
Johnson CD, et al. Accuracy of CT Colonography for Detection of Large Adenomas and Cancers. NEJM. 2008;359(12): 1207-1217.
Mulhall P, Veerappan GR, Jackson JL, et al. Meta-analysis: computed tomographic colonography. Ann Intern Med. 2005;142(8):635-650.
Yee J. Screening CT Colonography. Radiol Clin North Am. 2004;42(4):757-766.
Last reviewed November 2009 by
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