Imaging of the Colon

Abstract

As with the upper GI series, fluoroscopic colonography can be performed in either a single or double contrast fashion. In single contrast studies, the colon is filled only with opaque contrast such as barium or water-soluble contrast. This demonstrates an extrinsic displacement of the colon, such as might be seen in a pelvic mass in a patient with a gynecological malignancy, to the greatest advantage. Strictures and large intraluminal filling defects may also be identified (Fig. 31.1). Double contrast studies involve partially filling the colon with barium followed by insufflation with air (or carbon dioxide) via a rectal tube placed in the rectum for the purpose of elucidating polyps, early carcinomas, or inflammatory bowel disease. If there is a concern of obstruction or perforation, single contrast water-soluble enema may be used (Fig. 31.2a).