Virtual Colonoscopy or CT Colonography (CTC): Colorectal cancer is the second largest cause of death from cancer in the USA, killing around 60,000 people every year. 

• The incidence of colon cancer can be dramatically reduced with appropriate screening. The detection and removal of small, benign colon polyps reduces both the incidence and death from colorectal cancer.
• Unfortunately, only about 40% of people who should be screened ever get any screening at all.

What is a “Virtual Colonoscopy”? Many people are asking about Virtual Colonoscopies.(VC) 

• In 2008, the American Cancer Society endorsed virtual colonoscopy as an effective screening tool for colon cancer.
• Virtual colonoscopy, also know as CT Colonography, is a procedure in which a reduced radiation CT image of your abdomen is taken and processed to produce 2D and 3D images of the colon.
• State-of-the-art software such as the Viatronix work station turns the CT images into a “fly-through” movie which creates the best 3D images of your colon for the radiologist to review. 

In at least on large study (N. Engl. J. Med. 2003. 349:2191) virtual colonoscopy has been found to as effective at detecting colonic polyps as small as 6 mm as so-called optical or conventional colonoscopy. 

Virtual colonoscopy is even more sensitive than an air contrast barium enema, which is still part of some of the existing screening guidelines for colorectal cancer. 

It also uses much less radiation than a barium enema.  Optical colonoscopy, however, is is still the gold standard of care. 

Most insurances are not yet covering the cost of virtual colonoscopy, which costs close to $1000.  

In about 20% of virtual colonoscopies, a subsequent conventional colonoscopy is required either because a polyp or what may be a polyp is detected.  

People who require a conventional colonoscopy as follow up will incur additional costs, and will likely have to do another bowel prep when they do their colonoscopy.  There is no radiation associated with optical colonoscopies.

For conventional colonoscopy a "wet prep", in which a patient drinks a large jug of "go-lytely" the night before, is required.  This procedure also involves sedation and monitoring, time off from work and a second person to drive the patient home after the procedure.

For virtual colonoscopy, a dry prep, i.e. clear liquid diet for 24 hours, stool softeners, and a cathartic are required.  Patients can drive themselves home and return to normal activities, including work, immediately.

In the Boulder area, Front Range Preventive Imaging and Boulder Community Hospital are performing virtual colonoscopies.  At this time, I continue to recommend the conventional test.  Certainly, for those who would otherwise not do anything, or for whom sedation poses a health threat, etc, virtual colonoscopy is a reasonable alternative.