Anna Liachenko, BSc, MSc
Managing Editor, Geriatrics & Aging
Despite the fact that colon cancer is preventable, over 16,000 elderly Canadians were diagnosed with the disease in 1999. One out of every three patients diagnosed with the disease, died. Prevention of colon cancer requires discovery and removal of the precursor polyp at an early stage. However, elderly patients, who are at risk of developing colon cancer are largely underscreened. The reasons range from high invasiveness of current techniques and, thus, poor patient acceptance, to inability of the current methods to efficiently detect small polyps. Fortunately, a new non-invasive and highly efficient technique--virtual colonoscopy--has recently been introduced. This article will describe the technique and compare this technique with the traditional methods of colonoscopy and barium enema.
David J. Vining and associates, at the Bowman Gray School of Medicine first described virtual colonoscopy in 1994. It is based on analysis of two sets of axial images obtained from thin-section helical computed tomography (CT) scans of the abdomen and pelvis. The procedure starts with cleansing the patient's bowel (using a standard barium enema or colonoscopy bowel preparation) followed by colonic insufflation with room air or carbon dioxide. Then, the abdomen and pelvis are scanned with the patient holding their breath for the first 15 to 20 seconds (to cover the upper abdomen) and gently respiring for the remainder of the scan.