In reviewing the potential of virtual colonoscopy for colon cancer screening in my Caldwell Lecture to the American Roentgen Ray Society 2 years ago [2], I touched on certain issues distinct from the traditional technical imaging concerns of radiologists, by referring to the topics of "polyps and politics." I suggested that assessing the perceptions of this new method by those outside radiology is a vital strategic effort for those of us on the inside. The increasing attention paid to virtual colonoscopy in the lay media [3-5] and in nonradiology journals [6-8] confirms that virtual colonoscopy is not being introduced into a vacuum. It will be necessary to make the case for virtual colonoscopy within the broader context of colorectal cancer screening initiatives that encompass published national guidelines, scientific controversies, and turf competition.
There is and will be skepticism and resistance, in large part because of the widely held views that colonoscopy is the best (or only) test to screen for colorectal polyps and cancer [9, 10]. The notion of the "total colon examination" has greatly undermined the legitimacy of sigmoidoscopy, which covers only the distal colon and has been likened to "mammography of one breast" [9-11]. Similarly, double-contrast barium enema has been defined for nonra-diologists as ineffective for polyp detection by reports in the prestigious New England Journal of Medicine [12, 13]. In addition, the reimbursement for these two older procedures is so poor that neither primary care physicians nor radiologists have much interest in performing them. At the same time, marketing, education, and public relation efforts of the colonoscopy community have largely succeeded, and colonoscopy is accepted as the de facto gold standard for detecting colonic neoplasia.
Proponents of virtual colonoscopy will have to address the arguments used in favor of colonoscopy while at the same time proving that virtual colonoscopy gives accurate results and is acceptable to patients. As virtual colonoscopy becomes more widely available, closer inspection of the attributes and especially the weaknesses of conventional colonoscopy is therefore increasingly justified. To borrow from Chaucer, it is not unfair to notice the tarnish on the gold.
