A barium enema, also called a lower GI series, involves filling the large intestine with diluted barium liquid while X-ray images are being taken. Barium enemas are used to diagnose disorders of the large intestine and rectum. These disorders may include colonic tumors, polyps, diverticula, and anatomical abnormalities.
Usually, a barium enema can be performed on an outpatient basis. The patient may be asked to do the following in preparation for a barium enema:
- Drink clear liquids the day before the examination.
- Follow a special liquid diet one to two days prior to the procedure.
- Take a laxative, suppository, or drug to cleanse the bowel.
- Refrain from eating and drinking after midnight on the night before the examination.
These measures are done to empty the large intestine as any residue (feces) can obscure the image. However, a barium enema may be done without preparation, for example, to diagnose Hirschsprung's disease.
Barium enemas are performed in two ways:
Single-contrast image - The entire large intestine is filled with barium liquid. Single-contrast images show prominent abnormalities or large masses in the large intestine.
Double-contrast image - A smaller quantity of thicker barium liquid is introduced to the large intestine, followed by air. Double-contrast images show smaller surface abnormalities of the large intestine, as the air prevents the barium from filling the intestine. Instead, the barium forms a film on the inner surface.