What are the risks of performing a virtual colonoscopy?

Virtual colonoscopy does offer less risk than conventional colonoscopy since there is no anesthesia used. The risks include pain/discomfort from the air inflated into the rectum, risk of electrolyte shifts during bowel prep, and a small risk of a neurogenic bowel-brain reaction called vasocardiogenic syncope (some people pass out when that much air is passed into their bowels quickly). The most significant risk to this procedure is the possibility of missing a cancerous polyp.