The barium enema — colon X-ray — is used to detect changes or abnormalities in your colon. During the exam, liquid barium — and in some cases air — is inserted into your colon through the rectum. This is done to improve the view of your colon by an X-ray machine.
This test allows your doctor to examine your colon for:
- Narrowed areas (strictures)
- Growths of the lining (polyps)
- Small pouches in the wall (diverticula)
- Other abnormalities
Before the exam, your colon must be completely cleaned out (emptied). You may be told to take laxatives and possibly have an enema before the exam.
Your doctor will provide specific instructions about what to eat or drink before the test. Sometimes you may be put on a clear liquid diet for a day or two before the barium enema. Clear liquids include:
- Plain water
- Tea and coffee without milk or cream
- Any juice without pulp (no orange juice or tomato juice)
- Carbonated beverages
There are two types of barium enemas — single-column and air-contrast (double-contrast). The double-contrast barium enema is the test typically recommended for colorectal cancer screening.
SINGLE-COLUMN BARIUM ENEMA
During this test, you lie on your side on an X-ray machine table. A lubricated enema tube is inserted into your rectum. The radiologist connects a barium bag to the tube to deliver liquid barium into your colon.
Barium sulfate is a soft, metallic alkaline chemical. The barium temporarily coats the lining of your colon. This allows a clear silhouette of the shape and condition of your colon to show up on X-rays.
As your colon is filled with barium, you may feel the urge to have a bowel movement. The tube that's used to deliver the barium has a small balloon near its tip. When positioned at the entrance of your rectum, this balloon helps keep the barium from coming back out. Taking long, deep breaths through your mouth may help you relax.
You may be asked to turn and hold various positions on the examination table. This helps ensure that your entire colon is coated with barium and allows the radiologist to view the colon from various angles. The radiologist may press firmly on your abdomen and pelvis, manipulating your colon for better viewing. You may also be asked to hold your breath at times.
The radiologist can view your colon's shape on a television monitor attached to the X-ray machine. He or she will take a number of X-rays of your colon from various angles.
AIR-CONTRAST (DOUBLE-CONTRAST) BARIUM ENEMA
This procedure is similar to a single-column barium enema. The main difference is that air, in addition to barium, is put into your colon. The air expands the colon, which can improve the quality of the images.
The air-contrast method may increase the radiologist's ability to see small abnormalities, such as polyps. However, this technique may be a bit more uncomfortable than a single-column barium enema.
A barium enema exam takes about 20 minutes. An air-contrast barium enema can take 30 to 45 minutes. Either procedure may cause some minor abdominal cramping. Cramping usually ends soon after the test ends.
AFTER THE TEST
After the exam, the radiologist will remove the enema tip to allow much of the barium to drain from your colon.
The color of the barium will likely cause you to produce white, gray or pink stools over the next few days as it is expelled from your system. You may be given a cleansing enema or be instructed to take a laxative to remove the remaining barium. Because barium may cause constipation, you'll be advised to drink plenty of liquids during the next few days.
Check with your doctor if your stool is not normal colored within 2 to 3 days. This may indicate that you haven't passed all of the barium out of your colon.
If you had a negative barium enema, the radiologist did not find any abnormalities in your colon.
If your barium enema is positive, you may have an abnormality in your colon. Depending on the findings, you may be scheduled for additional testing, such as a colonoscopy, so that any abnormalities can be examined more thoroughly, biopsied or removed.
Consider asking your doctor if it was a good-quality exam. If the colon was not completely empty of stool at the time of the exam, then parts of the colon may have been obscured on the X-ray. In this case, there may have been abnormalities that were not seen. Your doctor may recommend having another barium enema in a year's time or sooner.
Barium enemas often are performed in conjunction with a flexible sigmoidoscopy exam. This dual approach allows for better evaluation of the sigmoid and rectum — about the last 2 feet of your colon. Both areas can sometimes be difficult to see with a barium enema alone.
PROS AND CONS
- No sedation is needed.
- When combined with flexible sigmoidoscopy, it screens the entire colon.
- Complications, such as perforation of the colorectal wall, are slight.
- It's less expensive than colonoscopy, costing about $250 to $500. Additional fees may apply.
- If you're 50 or older and have Medicare benefits, coverage includes a barium enema every 4 years for colorectal cancer screening.
- If you're at high risk of colorectal cancer, Medicare covers a barium enema every 2 years. However, colonoscopy is usually preferred.
- The test may miss small polyps or sometimes even small cancers.
- Biopsy and polyp removal cannot be done during testing, meaning you may need to follow up with a colonoscopy.
- Preparing for the procedure (emptying the colon) and the procedure itself can be unpleasant.