Current Status of CT Colonography

Colorectal cancer (CRC) is the third most common form of cancer and the second leading cause of cancer related mortality in the United States. Most cases of CRC however can be prevented through early detection and removal of pre-cancerous adenomatous polyps. This strategy is based on the “polyp-to-cancer” sequence suggested by Vogelstein. Even though the American Cancer Society (ACS) began advocating CRC prevention in the early 1980s and Medicare began reimbursement for CRC in 2001 in the US, approximately 50 million adults have never been screened for CRC. As a result, over 150,000 new cases of CRC are diagnosed each year. Recently, the ACS endorsed the use of CT Colonography for CRC screening in asymptomatic adults with average risk (for developing CRC) starting at age 50. Scanning and interpretation techniques for CT Colonography (virtual colonoscopy) have evolved considerably since it was first introduced by Vining in 1994. Thus, for lesions >5mm, the performance of CTC is comparable to that of optical colonoscopy (OC). Our aim is to describe the optimal technique for CTC and define its role in the colorectal cancer screening strategy.