What is the test?
A barium enema is an x-ray test used to examine the lower digestive tract (the colon and rectum). Because the colon and rectum are normally not visible on x-rays, you need to temporarily coat their inner surfaces with barium, a liquid that does show up on x-rays. This makes the outline of these organs visible on the x-ray pictures. This test is useful for diagnosing cancers and diverticuli (small pouches that may form in the intestinal wall).
How do I prepare for the test?
Tell your doctor if there is any chance that you might be pregnant. If you have diabetes and take insulin, discuss this with your doctor before the test.
You will be given very specific instructions to ensure that your colon is completely empty before the test. You may be told to eat only a light breakfast and a liquid lunch and dinner (such as broth and fruit juice) on the day before the test. You may also be instructed to drink a large amount of clear liquid between meals and to avoid dairy products. You will need to take a laxative, a medicine that stimulates your intestine to move things through more quickly, so that you have a bowel movement to empty the colon. It is a good idea to stay at home or at least near a bathroom for a few hours after taking the laxative. On the day of the test, do not eat any breakfast.
What happens when the test is performed?
You wear a hospital gown and lie on a table in the radiology department. To administer the enema, a nurse pushes a small tube an inch or two into your rectum, and then uses this tube to fill your colon and rectum with barium liquid. You may find the sensation of the filling of your colon somewhat strange (you might feel like you need to have a bowel movement), but it is not painful.
The x-ray for this test is taken as a video that begins immediately after your enema is started. The x-ray video is taken by a large camera positioned over your abdomen. Usually the room is darkened while the video is taken so that the doctor can watch the pictures on a TV screen. If the doctor wants to save a view in "freeze frame" (developed later for a closer look), you may be asked to hold your breath for a few seconds so that your breathing movement does not blur the image. A few more pictures may be taken after the lights are turned back on. After this, you are asked to empty your bowel in a nearby bathroom.
Usually one picture is taken of your abdomen after you have had your bowel movement, to make sure that the bowel has emptied well.
What risks are there from the test?
There are no significant risks. You will be exposed to a small amount of radiation during the test. The amount of radiation from a barium enema is larger than from a simple chest x-ray, but still very small — too small to be likely to cause any harm.
Must I do anything special after the test is over?
In some cases, if some stool was still present in your colon despite your preparation the day before, the test must be repeated.
How long is it before the result of the test is known?
It takes the x-ray department 30 minutes to an hour to develop the pictures from your barium enema, and it will take additional time for a doctor to examine the x-rays and to decide how they look. Typically you can get the results within a day or two.