Healthy Living

What is a Virtual Colonoscopy?

What is a Virtual Colonoscopy?

Also referred to as a VC, a virtual colonoscopy is an x-ray test that detects polyps, cancer or other disorders in the colon. Colonography is the medical term for this test.

How It's Done

There is a difference between an ordinary colonoscopy and a virtual colonoscopy. The ordinary colonoscopy uses a device which is long and lighted, known as colonoscope, which is put in the rectum and the colon.

A virtual colonoscopy is performed in the hospital’s radiology unit. A colonoscope is not used and neither are sedatives.

This is how the test is performed:

  • On a narrow table attached to a CT machine or an MRI, you are asked to lie on your left side
  • The knees should be pointing to the chest
  • A tiny, bendy tube is inserted into the rectum. To enlarge the colon for visibility, air is propelled up the rectum via the tube.
  • You are then told to lie on your back
  • The table glides to the MRI or CT machine, where pictures of the large intestine are taken.
  • You will lie on your tummy and pictures will be taken
  • Since movement can make the images blurry, you have to be extra still during the test. As each image is taken, the doctor may instruct you to hold your breath.

Three-dimensional images of the large intestines are put together by a computer. The pictures will then be seen on a video monitor.

How To Get Ready For a VC

This test is normally performed in the CT scanning unit of the medical center.  Information will be given to you on how to get ready for the appointment several days beforehand.

For the scanner to generate clear images of the bowel, your bowel should be empty. For three days prior to the procedure, a special diet may be recommended. This includes drinking clear liquids and minimizing solid foods. To empty the bowel, a laxative is used one day prior to the test.

The doctor can also recommend a liquid with iodine for several days prior to the procedure. You should consume this with meals. This will enable the bowel to be visible on the scanner.

If you are pregnant or are using any drugs, it is crucial to let the doctor know.  Just like all X-rays, a VC is not advised for women who are pregnant. 

The doctor will tell you what goes on prior, during and after the test, and if you will experience any pain. You can list down any questions you might want to ask about benefits, risks or other options of the procedure. This ensures total understanding between you and your doctor. The doctor may ask you to sign a consent form.

You can always call the hospital if you have any questions about getting ready for the appointment. 


You should be able to function normally immediately after the virtual colonoscopy. This is because there is no need for sedatives or painkillers in this procedure.

Feeling bloated for a while is expected. This is because of the air that was propelled to the bowel during the procedure. You may also have gas. Although not often, you may experience short-lived abdominal pain. Unless the doctor tells you otherwise, you will be able to return to your regular diet after the virtual colonoscopy.