A virtual colonoscopy (sometimes called a computed tomography colography) is a non-invasive procedure, meaning the screening is done completely outside the body. A virtual colonoscopy requires the same advance preparation as a standard colonoscopy.
During the virtual colonoscopy procedure, the physician inserts a small tube into the rectum to fill the colon with air. Then, instead of inserting a colonoscope into the rectum and through the colon like in a traditional colonoscopy, the physician uses MRI or CT scan technology to examine the colon from outside the body. The physician then carefully analyzes these images. If an abnormality is found, a traditional colonoscopy is required for further examination.
Virtual colonoscopy is a minimally invasive, safe and more comfortable procedure for colon screening. Recent studies have shown it to be comparable to conventional colonoscopy for finding polyps larger than one centimeter. The risk of cancer in smaller polyps is almost negligible. With virtual colonoscopy, 100% of the colon surface can be seen. It is estimated that physicians only see 70%-80% of the colon surface with conventional colonoscopy. Benefits of a virtual colonoscopy are: