What is virtual colonoscopy?

Virtual colonoscopy is not a colonoscopy at all. It is an air contrast barium cat scan (computerized tomography x-ray test) of the abdomen. It is very similar to the old-fashioned barium enema x-ray except that this examination is performed with a cat scan machine instead of a plain x-ray machine. Like the barium enema, this examination is performed by a radiologist. The patient must still undergo a laxative bowel cleanout procedure before this examination. Like the barium enema, a tube with a balloon is placed in the rectum. Barium sulphate and air are introduced into the rectum under pressure until the entire colon is distended, and pictures are taken with a spiral cat scan machine. Patients who have had this examination report that the pressure during the examination is more uncomfortable than any sensations during a regular colonoscopy since no sedation or pain medication is given for the "virtual" examination. This is purely a diagnostic examination, and no therapy such as polyp removal or cauterization of a bleeding lesion is possible with the cat scan machine.