A barium enema is an imaging test that uses a contrast mediumcontrast mediumA substance used in some diagnostic procedures to help parts of the body show up better on x-rays or other imaging tests. (barium sulphate) and x-rays to produce images of the entire large intestine (cecum, colon, rectum and anus).
Barium is a chalky, white liquid that coats the inside of the intestine and shows its outline clearly on an x-ray. Air or carbon dioxide may also be pumped into the intestine to improve the view (double-contrast barium enema). A moving image of barium as it passes through the intestine can be created with a special x-ray (fluoroscopy imaging) and a TV-like monitor.
A barium enema is also called:
- lower gastrointestinal (GI) series
- colon x-ray
- double-contrast barium enema
Why a barium enema is done
A barium enema may be done to:
- examine the lower GI tract (large intestine)
- follow up a positive fecal occult blood test (FOBT)fecal occult blood test (FOBT)A test to check for hidden blood in the stool (feces).
- find growths or polyps in the colon
- find the source of:
- unexplained bleeding
- problems with the intestine that cause malabsorption of nutrients
- lower abdominal pain
- diagnose cancer and other disorders of the lower digestive tract
How a barium enema is done
A barium enema is usually done as an outpatient procedure in the x-ray department of a hospital or clinic. The test usually takes 20–30 minutes.
- It is important for women to tell the x-ray technologist or radiologist if they are breast-feeding, pregnant or think they may be pregnant before having a barium enema and x-ray.
- Barium can interfere with other abdominal imaging tests, so these tests are usually done before barium studies.
- Preparation for a barium enema can vary, but it usually includes:
- Following a liquid diet for at least 24 hours before the test.
- Taking laxatives and possibly enemas to completely empty the intestines.
- Some departments may require people to follow a liquid diet and take laxatives for 48 hours before the barium enema.
- People with ostomies will need different preparation and testing.
- The person will be asked to remove clothing, jewellery and other objects that will be in the x-ray field and may interfere with quality of the x-ray.
During the test:
- The person lies on an x-ray table.
- Barium is given as an enema through a small plastic tube inserted through the anus into the rectum.
- A small amount of air or carbon dioxide is pumped through the enema tube into the colon to make it expand (double-contrast barium enema) and improve the view.
- X-rays are taken as the barium moves through the colon.
- The x-ray table is raised and tilted different ways to spread the barium throughout the colon.
- The person is asked to hold their anus closed during the test.
- Once the test is done and the enema tube is removed, the barium and air can be expelled.
- The person may be asked to wait until the x-rays are developed and the staff is sure that the image is clear.
- A mild laxative may be needed to get rid of the barium and prevent constipation.
- The person’s stools may be white or lighter in colour for a few days following the test.
- Drinking plenty of fluids after the procedure helps to flush the barium solution from the body and helps to prevent constipation.
Potential side effects
X-rays involve low levels of ionizing radiation, which has the potential to cause cancer and other defects. The number and complexity of x-rays needed to diagnose and determine the extent of a disease can vary. Even with multiple and repeated x-rays, the total dose of radiation and the associated risk is small. X-rays are strictly monitored and controlled to make sure they use the smallest amount of radiation possible. The expected benefits of the x-rays must always outweigh any possible risk in order for the x-rays to be done.
On rare occasions, the contrast medium may cause an allergic reaction.
What the results mean
A barium enema can show:
- a blockage (obstruction) in the intestine
- a mass, such as a polyp or tumour, within the colon
- The mass may show up as an irregular outline extending from the wall of the colon.
- X-rays may not detect very small polyps or tumours.
- Biopsies cannot be taken nor polyps removed during this test.
- masses or tumours in other organs that are pressing on the colon
What happens if a change or abnormality is found
The doctor will decide whether further tests, procedures, follow-up care or additional treatment are needed.
Special considerations for children
Being prepared for a test or procedure can reduce anxiety, increase cooperation and help the child develop coping skills. Parents or caregivers can help prepare children by explaining to them what will happen, including what they will see, feel and hear during the test.
- A parent can stay with the child during the test.
- When barium enters the colon, the child may feel like they have to have a bowel movement.
- The child may also have a feeling of fullness, some cramping and general discomfort after the test.
The preparation you can provide for a barium enema depends on the age and experience of the child. See the following for more age-specific information on helping children cope with tests and treatment.
Support from someone who has ‘been there’
The Canadian Cancer Society’s peer support program is a telephone support service that matches cancer patients and their caregivers with specially trained volunteers.