CT colonography: what the gastroenterologist needs to know

[...]virtual 'fly throughs' of the colon were created, simulating views encountered during the passage of an endoscope at optical colonoscopy. 3 4 Currently, CT colonography describes the technique of combined two- and three-dimensional review of abdomino-pelvic CT data acquired in two anatomical positions (usually patient lying prone and supine) following colonic preparation and insufflation with gas. [...]faecal residue is rapidly discriminated from colonic neoplasia, enabling detection of polyps in fluid filled segments, thus potentially improving reader confidence and specificity. 9 Use of faecal tagging agents, combined with either 'dry' or 'wet' laxatives are now used routinely in several centres around the world and, although more evidence is awaited, expert opinion suggests use of faecal tagging has improved the positive predictive value of CT colonography, decreased interpretation times and reduced examination inadequacy rates (4% to