Enema, barium

: A series of x-rays of the lower intestine (colon) and rectum that are taken after the patient is given an enema with a white, chalky solution that contains barium. The barium outlines the intestines on the x-rays. These x-rays permit the detection of colon and rectal abnormalities including diverticulosis, diverticulitis, abnormal colon movement, dilation (widening) of the colon, polyps and cancers of the colon and rectum. Air can be instilled into the colon along with the barium contrast medium to further define structures of the large bowel and rectum. Polyps and small cancers are more readily found using this method which is called an air contrast barium enema or a double-contrast barium enema. This is the only kind of barium enema that is appropriate for detecting colorectal polyps and potentially curable colorectal cancers. The barium enema was for years the only way to do a complete examination of the colon shy of surgery, but with the advent of fiberoptic technology and the widespread use of colonoscopy, the role of the barium enema has declined. Although the barium enema is clearly better than colonoscopy in regard to safety and cost, colonoscopy in recent year has been replacing barium enemas.