Virtual or Optical Colonoscopy? 
Thursday, 22 April 2004 

Choosing the Colonoscopy that is Right for You


Virtual colonoscopy may be the hot topic in the news right now for colorectal cancer screenings, but is this high tech approach right for you or your loved ones, or are you better off sticking with the standard colonoscopy?


Colon cancer screenings, including a yearly Fecal Occult Blood Test, are recommended starting at age 50 for adults who are at an average risk for developing the disease.  A colonoscopy is recommended every ten years.  However, only half of the people at risk for developing colorectal cancer have themselves screened.  A person is considered at risk if they have any of the following factors:

  • A strong family history of colorectal cancer or polyps, in a first-degree relative (parent, sibling or child) younger than 60 or in two first-degree relatives of any age.
  • A known family history of hereditary colorectal cancer syndromes.
  • A personal history of colorectal cancer or adenomatous polyps.
  • A personal history of chronic inflammatory bowel disease.


Not all medical professionals agree on whether virtual colonoscopies are comparable in effectiveness to standard colonoscopies in finding polyps, the masses of tissue that grow into the center of the tube that makes up the colon or rectum and may develop into cancer.


With both the standard and virtual colonoscopy, patients must take laxatives and an enema to clean out the colon before the procedure.  Patients in a standard colonoscopy are sedated during the procedure.


In a standard colonoscopy, a long, slender, flexible tube, with an attached camera, called a sigmoidoscope, is inserted through the rectum up into the colon.  This allows the doctor to see the entire lining of the colon on a display.  A virtual colonoscopy is a type of CT scan that takes an x-ray of the patient’s colon, then sends the data to computer software which analyzes the it and creates images similar to those in the standard colonoscopy.


The potential advantages to a virtual colonoscopy are that the test can be done quickly, with no sedation.  However, the most advanced techniques and software are not available everywhere, nor is it necessarily covered by insurance companies.  


If a doctor finds a large polyp, tumor or any other abnormalities during a standard colonoscopy, a biopsy is usually done immediately, during the same procedure.  However, since virtual colonoscopies are only visual, if a polyp is seen, the patient will often have to undergo a standard colonoscopy later to have  it removed.  There are no guidelines as of yet on how large a polyp should be before a standard colonoscopy is recommended following a virtual colonoscopy.


Colonoscopies, both standard and virtual, are only two types of screenings for colorectal cancer.  Others include a barium enema with air contrast and a fecal occult blood test.  Check with your doctor to find the screening that is right for you, especially if you have a family history of colorectal cancer or symptoms, such as a change in bowel habits or rectal bleeding.