[Optical colonoscopy and virtual colonoscopy: the current role of each technique]

The importance of optical or conventional colonoscopy in diagnosing colon disease is undisputed. In this context, optical colonoscopy is the gold standard against which other techniques must be validated. Apart from enabling direct inspection of the colonic mucosa, optical colonoscopy enables biopsies and techniques to treat and prevent colorectal cancer. Virtual colonoscopy or CT colonography has been validated in multicenter studies; virtual colonoscopy is as sensitive as optical colonoscopy for the detection of polyps and colon cancer. It is currently the only valid alternative to optical colonoscopy. Its role in patients with medium or high risk of colon cancer is in the process of being defined as multidisciplinary teams gain experience. This article aims to discuss the usefulness of virtual colonoscopy in different clinical situations, emphasizing the situations in which there is enough scientific evidence, and to discuss the controversies surrounding its possible use for population-based screening.