Virtual CT colonoscopy (also called CT colonography) is a non-invasive radiological technique that combines CT scanner and computer technology to provide an accurate method to screen for large colorectal polyps and cancer. Recently the American Cancer Society recommended this procedure as an option for colorectal cancer screening; one of three tests (Colonoscopy, Double Contrast Barium Enema, and Virtual Colonoscopy) that examine the entire colon. The virtual CT colonoscopy examines the entire colon, is minimally invasive, quick, and requires no anesthesia. A CT scanner provides hundreds of X-ray images of the entire colon as well as the abdomen/pelvis area. Sophisticated image processing computers then produce 2 and 3 dimensional images of the colon.

Cleveland Clinic 's Imaging Institute has experienced technologists and staff radiologists who have completed and interpreted over 1500 of these virtual CT colonoscopy scans.

This exam is not suitable for everyone. If medically feasible, a conventional optical colonoscopy is preferable if a person is less than 50 years of age and has one of the following conditions:

  • Recent unintentional weight loss of greater than 10 pounds
  • Recent experience of GI discomfort, change in bowel habits, anemia or bleeding
  • Diagnosed inflammatory bowel disease (such as Crohn’s or ulcerative colitis)
  • A family history of colorectal polyps or cancer including familial adenomatous polyposis or hereditary non polyposis colorectal cancer

Medicare and/or insurance reimbursement/coverage is available only if there is a documented medical reason for this type of CT scan. Examples of this include patients who have had an incomplete conventional colonoscopy and patients who have a high risk for bleeding such as those taking anticoagulants like Coumadin or patients with bleeding disorders such as hemophilia.

Virtual CT colonoscopy for colon screening is currently not covered under most major insurance plans or Medicare and a payment is required at the time of service.

Test Description

In order to properly scan the colon two conditions must be met.

First, bowel cleansing must take place. Stool within the colon needs to be removed because CT images cannot see through stool and stool adheres to the colon wall. Your doctor will instruct you on the type of bowel cleansing laxative you should use.

In addition to bowel cleansing, there are some dietary restrictions:

  • One week prior to the exam, no eating of hard nuts and seeds, such as peanuts, cashews, popcorn, sunflower, poppy, and sesame seeds.
  • Three days prior to the exam, no eating of high residue foods such as bran cereal and raw vegetables.
  • One day before the procedure:

If you have diabetes, you must discuss adjusting your diabetes medication dose with your doctor prior to beginning a clear liquid diet.

Second, the colon walls must be distended in order to see colon polyps. The colon is inflated with carbon dioxide gas. This is the same gas as in gingerale or soda pop; therefore, following the procedure the gas will either be quickly absorbed or passed out of the rectum within approximately 5 to 10 minutes. Once the colon is distended, two separate CT scans (one lying on the stomach and one on the back) will be taken in order to view the entire colon.

After the procedure, a normal diet and activity may be resumed.

Test Preparation

Virtual CT colonoscopy examines the entire colon. Good bowel cleansing is very important with this procedure. The colon must be completely clean so that the radiologist can clearly view the colon lining and accurately diagnose any problem. Your doctor will prescribe the type of bowel cleansing laxative you should use.

Step 1: Dietary Restrictions

  • One week before procedure - Stop eating nuts and hard seeds (such as peanuts, cashews, popcorn, sunflower, poppy and sesame seeds)
  • Three days before procedure - Stop eating high fiber foods (such as bran, oatmeal, whole grains, raw fruits and vegetables)
  • One day before procedure - Clear liquid diet only. Do not eat any solid foods. Drink plenty of clear liquids including:

If you have diabetes, you must discuss adjusting your diabetes medication dose with your doctor prior to beginning a clear liquid diet.

Step 2: Laxative Bowel Cleansing Preparation

Purchase from your local store or pharmacy:

  • One bottle of Miralax® or generic-equivalent (polyethylene glycol) - 238 grams (approximately 8.3 oz)
  • One-64 ounce or two-32 ounce bottles of Gatorade (any flavor) or any clear liquid

Step 3: Bowel Contrast Preparation

Cleveland Clinic Home Delivery will send to your home a bowel contrast kit with:

  • 4 Dulcolax (biscacodyl) tablets which will stimulate the bowel
  • 1 cup of banana flavored barium which will coat stool in the colon
  • 1 ounce of Gastroview (diatrizoate) which will coat the colon lining
  • A detailed instruction sheet with ingestion times for both cleansing laxative and bowel contrast preparations

Step 4: Do not eat or drink anything after midnight

AM meds should be taken:

  • Preferably after the procedure is completed
  • Prior to procedure with no more than 1 oz of liquid


The virtual CT colonoscopy procedure is offered Monday through Friday, 8:30 a.m. - 10 a.m. at the following locations:

Main Campus (QB1)
9500 Euclid Avenue, Cleveland, OH

Beachwood Family Health & Surgery Center
26900 Cedar Road, Beachwood, OH

Elyria Family Health & Surgery Center
303 Chestnut Commons Drive, Elyria, OH


For more information or to schedule a test, please call 216.444.6919.

Orders and prescriptions may be faxed to 216.636.0159.

Please note that a physician referral is required.

Reviewed by a Cleveland Clinic medical professional.

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