CT colonography

Screen for colon cancer with computed tomography (CT) colonography at Community Hospital of the Monterey Peninsula. Also called a virtual colonoscopy, this test is a quicker, less invasive way than traditional colonoscopy to check for early signs of disease in your large intestine. The results help your doctor determine how to keep your digestive system as healthy as possible.

Should I get a virtual colonoscopy?

Rely on your primary care doctor to recommend a colon cancer screening schedule based on your health history, your lifestyle, and the latest screening guidelines. CT colonography is one of the most comprehensive screenings available. It shows not only detailed images of your large intestine, but can spot problems in other areas of your abdomen, too.

How to prepare

Before a virtual colonoscopy, you must:

  • Take laxatives to empty your bowels so doctors can see the lining of your colon
  • Drink a barium solution that helps polyps (potentially cancerous growths) show up better on the images
  • Limit the types of foods and beverages you consume so your colon is clear the day of the exam

Follow all CT colonography preparation instructions [PDF] to ensure clear, accurate images. Ask us for advice to make getting ready as easy as possible.

What to expect

After you arrive for your screening, you’ll change into a gown. Then, an imaging technologist will help you get into position on a CT table. You won’t need anesthesia to prevent pain for this short exam.

A doctor will insert a small, flexible tube two inches into your rectum. The tube gently pumps carbon dioxide into the colon to eliminate folds or wrinkles that could make it hard to see polyps. You may feel some bloating or pressure at first, but your body will quickly and safely absorb the carbon dioxide.

Next, the table will move through the opening in the CT scanner. You’ll need to hold your breath for 15 seconds as the machine takes 3D pictures of your large intestine and abdominal area. Then, we’ll help you move into a different position for a second trip through the scanner. After the second scan, your doctor will remove the tube.


You can go home or return to your daily activities immediately after a virtual colonoscopy.

Other colon cancer screening options

Ask your primary care doctor about additional tests that screen for colorectal cancer:

  • Colonoscopy (traditional) – Passes a thin tube with a light and camera through your entire large intestine
  • Fecal occult blood test (FOBT) – Checks a stool sample for blood
  • Flexible sigmoidoscopy – Looks at only the lower part of your colon, unlike a traditional or virtual colonoscopy, which examines the whole large intestine

Talk to your doctor

Ask your primary care provider for a referral to a gastroenterologist.

Getting test results

If you have an online MyChart account, you’ll likely see your test results in the patient portal within 24 hours. Your doctor will call to explain them and discuss next steps. Wait until you talk to your doctor before trying to understand what they mean.

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