A barium enema is a special X-ray exam used to detect changes or abnormalities in the large intestine (colon). There are two types of barium enema exams:

  • Single-column barium enema. A single-column barium enema begins by coating the inner surface of the colon with a solution containing the metallic element barium. This allows the doctor to see a silhouette of the shape and condition of your colon.
  • Air-contrast (double-contrast) barium enema. During an air-contrast barium enema, air is inserted into your colon after the barium coating is in place. The air expands the colon and improves the quality of the X-ray images.

A barium enema exam doesn't require sedation. However, preparing for a barium enema — emptying the colon with laxatives or enemas or both — can be unpleasant.

Your doctor may recommend a barium enema exam to:

  • Investigate intestinal signs and symptoms. A barium enema can help your doctor explore possible causes of abdominal pain, rectal bleeding, a change in bowel habits, chronic diarrhea and other intestinal problems.
  • Identify specific colon problems. A barium enema can help your doctor identify growths (polyps) in your colon, diverticulitis or other colon problems.

In addition, a double-contrast barium enema may also detect cancer. If any growths (polyps) are detected during a barium enema, a follow-up colonoscopy may be needed. However, newer techniques, such as CT colonography, may be used instead of barium enema because newer techniques can produce better images.

Barium enema exams generally aren't done during pregnancy.

A barium enema exam poses few risks. Rarely, complications of a barium enema exam may include:

  • Inflammation in tissues surrounding the colon
  • Obstruction in the gastrointestinal tract
  • Tear in the colon wall

Before a barium enema exam, you'll need to clean out (empty) your colon. Any residue in your colon may obscure the X-ray images or be mistaken for an abnormality.

To empty your colon, follow your doctor's instructions carefully. You may be asked to:

  • Follow a special diet the day before the exam. Typically, you won't be able to eat the day before the exam. Drinks may be limited to clear liquids — such as plain water, tea and coffee without milk or cream, broth, and clear carbonated beverages. You may not be able to eat or drink anything after midnight the day of the exam.
  • Take a laxative the night before the exam. The laxative may be in pill or liquid form.
  • Use an enema kit. In some cases, you may need to use an over-the-counter enema kit — either the night before the exam or a few hours before the exam — to empty your colon.
  • Adjust your usual medications. Remind your doctor of your medications at least a week before the exam. You may need to temporarily stop taking certain medications days or hours before the exam.

During the exam

During a barium enema exam, you'll wear a gown but likely nothing else. Sedation isn't usually necessary.

You'll begin the exam lying on your side on an X-ray machine table. An X-ray will be taken to make sure your colon is clean. Then a lubricated enema tube will be inserted into your rectum. A barium bag will be connected to the tube to deliver the barium solution into your colon.

The barium solution temporarily coats the lining of your colon. This provides a silhouette of the shape and condition of the inner lining of your colon on X-ray images. If you're having an air-contrast (double-contrast) barium enema, air will be inserted through your rectum to expand the colon and improve the quality of images.

The tube that's used to deliver the barium has a small balloon near its tip. When positioned at the entrance of your rectum, the balloon helps keep the barium inside your body. As your colon fills with barium, you may feel the urge to have a bowel movement. Abdominal cramping may occur as well. To relax, take long, deep breaths. Do your best to hold the enema tube in place.

You may be asked to turn and hold various positions on the exam table. This helps ensure that your entire colon is coated with barium and allows the radiologist to view the colon from various angles. You also may be asked to hold your breath at times.

The radiologist may press firmly on your abdomen and pelvis, manipulating your colon for better viewing on a monitor attached to the X-ray machine. A number of x-rays will likely be taken of your colon from various angles.

A barium enema exam typically takes about 30 to 45 minutes.

After the exam

After the exam, most of the barium will be removed from your colon through the enema tube. When the tube is removed, you'll be able to use the toilet to expel additional barium and air. Any abdominal cramping usually ends quickly, and you'll be able to return to your usual diet and activities right away.

You may have white stools for a few days as your body naturally removes any remaining barium from your colon. Because barium may cause constipation, it's important to drink extra fluids in the days following the exam. Your doctor may recommend a laxative if needed.

Check with your doctor if you're unable to have a bowel movement or pass gas more than two days after the exam or if your stool doesn't return to its normal color within a few days after the exam. This may indicate that some amount of barium remains in your colon.

Ask your doctor to review the results of your barium enema with you.

  • Negative result. A barium enema exam is considered negative if the radiologist detects no abnormalities in the colon. If you had the barium enema to screen for colon cancer and you're at average risk — you have no colon cancer risk factors other than age — your doctor may recommend waiting five years and then repeating the exam.
  • Positive result. A barium enema exam is considered positive if the radiologist detects abnormalities in the colon. Depending on the findings, you may need additional testing — such as a colonoscopy — so that any abnormalities can be examined more thoroughly, biopsied or removed.

If your doctor is concerned about the quality of your X-ray images, he or she may recommend a repeat barium enema or another type of screening test.

Jun. 17, 2011