Virtual Colonoscopy

Colorectal cancer is the second largest cause of death from cancer in the USA, killing around 60,000 people every year.  The detection and removal of small, benign colon polyps reduces both the incidence and death from colorectal cancer.

Everyone is asking about virtual colonoscopy.  Virtual colonoscopy is a procedure in which a CT image of your abdomen is taken and processed to produce an image that is very much like looking through colonoscope. 

At least on large study (N. Engl. J. Med. 2003. 349:2191) has now been published and indicates that virtual colonoscopy is 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.