Although it's not from a typical medical journal, this article on CT "Virtual Colonoscopy" is an interesting read. The procedure has a few pros and cons to consider (emphasis mine):
While CT colography has numerous advantages in comparison to other leading screening tests, such as high patient acceptance, safety, lack of sedation, and extracolonic review during polyp screening, it also has several limitations, including inability to perform simultaneous detection and removal of polyps, exposure to ionizing radiation, and requirement of colonic cleansing with cathartics.I think the biggest issue with virtual colonoscopy from a medical perspective is the inability to remove or biopsy polyps that are discovered....so the patient then has to undergo a second, "non-virtual" colonoscopy, preceded by a second bowel prep. I find that patients complain the most about the mechanical bowel prep, rather than the procedure itself; presently, a mechanical prep is still required for CT colography, but "fecal tagging" (see article) may reduce or eliminate that requirement.
Overall, I suspect that patient demand will continue to push this procedure along. A multicenter trial is underway to try to determine if "virtual" colonoscopy is as accurate as "real" colonoscopy -- patients are being sought here.