Virtual colonoscopy v. standard colonoscopy

What is a virtual colonoscopy?

A virtual colonoscopy is an imaging procedure which uses CT scans and computer software to produce a three-dimensional image of the colon and rectum. Although most people think that virtual colonoscopy is new, it was first considered more than a decade before it became a reality in the early 2000’s thanks to improvements in technology and software.

Where is a virtual colonoscopy performed?

A virtual colonoscopy is performed in the hospital or clinic Imaging/ Radiology Department.  Please note The Austin Diagnostic Clinic does not perform virtual colonoscopy.

What is the preparation required for a virtual colonoscopy?

Some preparations vary but you will be asked to take a laxative or other medication at home the day before to clear the stool from the colon. This is the same preparation you would follow for a standard colonoscopy.

How is the procedure performed?

You will be asked to lie down on your side with your knees toward your chest. A small flexible tube will be inserted into your rectum. Air is pumped into the tube to make the colon bigger and easier to see. After this, you will be asked to lie on your back. The bed slides through an open ring where x-rays create images of your colon.

These pictures are viewed on a video monitor. The exam takes about 20 minutes.

Differences between virtual and standard colonoscopy include:

  • Both procedures can spot large polyps. Virtual colonoscopy is not as detailed as standard colonoscopy and may miss small polyps or flat lesions.
  • No sedation is necessary for a virtual colonoscopy and you are usually able to resume normal activities after the test. Standard colonoscopy requires IV sedation and is usually performed in an outpatient surgery facility.
  • There is minimal risk of puncturing the colon using virtual colonoscopy.
  • Virtual colonoscopy requires radiation exposure. Although relatively small, it could add up with repeated testing.
  • If polyps are found during a virtual colonoscopy they cannot be removed or a biopsy performed at the time of the exam. You would have to have a standard colonoscopy for those procedures. Standard colonoscopy is considered the “gold standard” by many professionals because it provides the opportunity to identify precancerous polyps and cancer and do the biopsy or removal of these lesions as soon as possible.
  • Virtual colonoscopy is not yet covered by Medicare.
  • There is a lack of standardization for virtual colonoscopy. It is an option but limitations and the unanswered question still remain.

It is important for you to discuss colon cancer screening options with your doctor.