CT colonography (virtual colonoscopy): technique, indications and performance

Worldwide, colorectal cancer is the third most frequent cancer occurring in both sexes. Screening programs for early detection enable detection of tumors at an earlier stage and have been shown to reduce death rate. Currently, colonoscopy is the investigation of choice for colorectal cancer screening and for investigation of patients with suspected colorectal cancer. However, colonoscopy remains an invasive technique requiring anesthesia, with a risk of perforation and bleeding. In addition, even experienced colonoscopists may be unable to complete the colonoscopy due to multiple reasons such as severe diverticulosis, stricture, obstructing mass, or fixation of colonic loops. CT colonography, also known as virtual colonoscopy, is a relatively new technique that is becoming increasingly popular. The technical aspects, indications, advantages and diagnostic performance of this technique are briefly reviewed.