Barium Enema

Air Contrast Study, Lower Gastrointestinal Series

Test Overview

A barium enema, or lower gastrointestinal (GI) examination, is an X-ray examination of the large intestine (colon and rectum). The test is used to help diagnose diseases and other problems that affect the large intestine. To make the intestine visible on an X-ray picture, the colon is filled with a contrast material containing barium. This is done by pouring the contrast material through a tube inserted into the anus. The barium blocks X-rays, causing 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, which outlines the intestine and reveals large abnormalities.
• In a double-contrast or air-contrast study , the colon is first filled with barium and then the barium is drained out, leaving 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, making it easier to see colon polyps, colorectal cancer, or inflammation.

In some cases, the single-contrast study may be preferred for specific medical reasons or for older people who may not be able to tolerate the time-consuming and somewhat more uncomfortable double-contrast study. However, if the results are not clear or there is a strong suspicion of colorectal cancer, a double-contrast study may also be done.

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Author:	Maria G. Essig, MS, ELS	Last Updated: May 2, 2007
Medical Review:	Kathleen Romito, MD - Family Medicine Jerome B. Simon, MD, FRCPC, FACP - Gastroenterology
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