Test Overview

A barium enema is an X-ray exam of the large intestine (colon and rectum). It may also be called a lower gastrointestinal (GI) exam. The test is used to help find diseases and other problems that affect the large intestine. The colon is filled with a contrast material that contains barium so that the intestine can be seen on an X-ray. This is done by pouring the contrast material through a tube inserted into the anus. The barium blocks X-rays. This causes the barium-filled colon to show up clearly on the X-ray picture.

There are two types of barium enemas.

  • In a single-contrast study, the colon is filled with barium. This outlines the intestine and shows large abnormalities.
  • In a double-contrast or air-contrast study, the colon is first filled with barium, and then the barium is drained out. This leaves only a thin layer of barium on the wall of the colon. The colon is then filled with air. This provides a detailed view of the inner surface of the colon. It makes it easier to see narrowed areas (strictures), diverticula, and swelling.

The single-contrast study may be the better choice for certain medical reasons. It may also be a good choice for older people who may not be able to tolerate a double-contrast study, which takes longer and is more uncomfortable. If the results are not clear, then a double-contrast study may also be done.