The evolving role of CT colonography.

Colorectal cancer (CRC) screening is widely recommended as part of standard preventive care. All average risk persons over the age of 50 y are eligible. Various authorities have advocated fecal occult blood testing, flexible sigmoidoscopy, barium enema and colonoscopy at varying intervals as acceptable screening options. Despite the array of choices, CRC screening lags in frequency behind other cancer screening maneuvers like mammography or Pap smear. Of late, there is growing interest in CT colonography (CTC) as another screening option. CTC, or virtual colonoscopy, may represent an attractive, non-invasive method of CRC screening that provides images akin to traditional colonoscopy. Improvements in CTC performance, especially when coupled with declining costs, suggest that CTC's role in average risk screening will increase in the future. This review summarizes available data about the efficacy of CTC in average and high risk screening populations. Current indications as well as limitations to this technology are discussed, as are practical issues like the cost-effectiveness of CTC for widespread use.