Clinical results of CT colonoscopy.

With increasing emphasis among the medical community on the early diagnosis and staging of colorectal cancer, interest has grown in CT colonography as a developing technique to challenge existing methods such as the barium enema and conventional colonoscopy. First introduced in 1994, CT colonography has experienced dramatic improvements in both hardware and software capabilities, resulting in shorter scanning times, greater user-friendliness and promising performance statistics. The recent development in multi-slice CT scanners has meant the ability to scan patients in a single breath hold, while innovations in image reconstruction and manipulation have optimised and yet greatly simplified study interpretation. Recent imaging protocols that use IV contrast to stage known or suspected colorectal cancer have been described. Current interest has focused on improving patient acceptance of the technique through the development of faecal tagging agents to avoid full bowel catharsis. This review summarises the development of CT colonography to date, evaluates its applications and performance in the detection and screening of colorectal polyps and looks at future directions of this exciting technique.