A barium enema is given in order to perform an x-ray examination of the large intestines. Pictures are taken after rectal instillation of barium sulfate (a radiopaque contrast medium).

Alternative Names

How the test is performed

This test may be done in an office or a hospital radiology department. You lie on the x-ray table and a preliminary x-ray is taken. You then lie on your side while a well-lubricated enema tube is inserted gently into your rectum.

~Barium, a radiopaque (shows up on x-ray) contrast medium, is then allowed to flow into your colon. A small balloon at the tip of the enema tube may be inflated to help keep the barium inside. The flow of the barium is monitored by the health care provider on an x-ray fluoroscope screen, which is like a TV monitor. Air may be puffed into the colon to distend (expand) it and provide better images.

You are asked to move into different positions and the table is slightly tipped to get different views. At certain times when the x-ray pictures are taken, you hold your breath and are still for a few seconds so the images won't be blurry.

The enema tube is removed after the pictures are taken and you are given a bedpan or helped to the toilet. You then expel as much of the barium as possible. One or two x-rays may be taken after the barium is expelled.

How to prepare for the test

Thorough cleaning of the large intestine is necessary for accurate pictures. Test preparations include a clear liquid diet, drinking a bottle of magnesium citrate (a laxative), and warm water enemas to clear out any stool particles.

How the test will feel

There is a feeling of fullness during the procedure, moderate-to-severe cramping, the urge to defecate, and a general discomfort. The x-rays themselves are painless.

Why the test is performed

The test is used to detect colon cancer. The barium enema may also be used to diagnose and evaluate the extent of inflammatory bowel diseases.

Normal Values

~Barium should fill the colon uniformly, showing normal bowel shape and position, and an open passage free of obstruction.

What abnormal results mean

Abnormal findings may include cancer, diverticulitis (small pouches formed on the colon wall that can become inflamed), polyps (a tumor, usually noncancerous, that grows on the mucous membrane ), inflammation of the inner lining of the intestine (ulcerative colitis ), and irritable colon. An acute appendicitis or twisted loop of the bowel may also be seen.

Additional conditions under which the test may be performed:

• Annular pancreas
• CMV gastroenteritis/colitis
• Colorectal polyps
• Crohn's disease (regional enteritis)
• Hirschsprung's disease
• Intestinal obstruction
• Intussusception (children)
• Pyloric stenosis

What the risks are

There is low radiation exposure. X-rays are monitored and regulated to provide the smallest amount of radiation exposure needed to produce the image. Most experts feel that the risk is low compared with the benefits. Pregnant women and children are more sensitive to the risks of the x-ray.