Barium Enema

A barium enema is an imaging test in which the large intestine is visualized using a contrast substance to obtain a more defined view of its structure.

Enema opacoEnema opaco
General DescriptionPre-test PreparationHospitals

General Description

A barium enema, also known as a contrast enema, is an examination that produces X-ray images of the large intestine. Unlike conventional radiography, the patient receives a barium enema to fill the colon, making it more easily identifiable on X-ray images.

Because barium completely coats the colon, it appears bright white on images with a clearly defined outline. This facilitates the detection of any abnormalities.

The procedure can be performed in two ways:

  • Single-contrast barium enema: barium is used as the contrast agent to enhance visualization of the intestine.
  • Double-contrast barium enema: in addition to barium, air is introduced into the colon to expand it, allowing the intestinal mucosa to appear more clearly defined and revealing more details. This method is preferred when polyps, inflammation, or cancerous tumors are suspected.

Although widely used in the past, barium enemas are increasingly being replaced by colonoscopy, which allows direct visualization of the colon and simultaneously enables biopsy collection or treatment (such as polyp removal or ulcer cauterization).

When is it indicated?

A barium enema is indicated in patients with the following symptoms:

This procedure can help diagnose:

  • Inflammation
  • Polyps
  • Diverticulosis: formation of small pouches (diverticula) in the wall of the large intestine
  • Diverticulitis: inflammation or infection of a diverticulum
  • Intestinal ulcers: sores in the tissue lining the interior of the intestine
  • Intestinal fistulas: abnormal connections between the intestine and other parts of the body
  • Crohn’s disease: chronic autoimmune-mediated intestinal inflammation
  • Ulcerative colitis: chronic condition causing inflammation and ulcer formation in the colon and rectum
  • Intestinal obstruction: abnormal blockage that prevents passage of intestinal contents
  • Colon cancer
  • Rectal cancer

How is it performed?

A barium enema is performed in the radiology department and consists of two distinct phases:

  1. A preliminary X-ray is taken. The patient is positioned between the X-ray emitter and a plate that captures the images.
  2. After administering the enema, a second X-ray is taken.

When X-rays pass through the body, dense tissues absorb more radiation and appear white, whereas soft tissues allow more X-rays to pass through and appear darker. Thus, the images show bones and contrast material in lighter tones, while other organs appear in varying shades of gray.

Risks

A barium enema involves ionizing radiation, but the dose is very low (6–7 mSv), which does not pose a health risk. For comparison, the average annual natural background radiation is estimated at 2.4 mSv.

Nevertheless, it is not recommended in pregnant women or those who may be pregnant, as radiation may harm the fetus.

Potential complications, although uncommon, include:

  • Allergic reaction to the contrast agent
  • Intestinal obstruction due to barium accumulation
  • Intestinal perforation caused by enema pressure, which could lead to peritonitis if it occurs
  • Rectal irritation or injury from catheter insertion (rare)

Due to these potential complications, the test is also contraindicated in patients with severe abdominal pain, risk of abdominal perforation, or recent colon biopsy.

What to expect from a barium enema

Patients should arrive at the medical center one hour before the appointment for preparation. After signing the informed consent forms, they change into a hospital gown and enter the radiology room.

Once in the room, he lies face up on the examination table to have his first x-ray taken. During exposure, staff leave the room, but the patient is continuously monitored. Image capture takes only a few seconds.

For barium administration, the patient lies on their side with a relaxed sphincter. A lubricated catheter is gently inserted through the rectum into the colon, and contrast material is injected. Air may be introduced afterward to expand the intestine.

Once contrast is in place, X-rays are taken again. Patients must retain the liquid despite the urge to evacuate. After completion, evacuation is facilitated immediately, so the effort is brief.

Post-procedure, mild discomfort is common, including:

  • Abdominal discomfort: gas, cramps, bloating (relieved after defecation)
  • Constipation: barium may impede bowel movements, mitigated by increased fluid intake
  • Light-colored stools due to contrast
  • Rectal irritation from catheter passage

Persistent discomfort or pain should prompt contact with the medical center.

Results are provided at the consultation with the requesting specialist a few days after the procedure.

Specialties in which a barium enema is requested

Barium enemas are requested within General and digestive system surgery and are performed in Radiology.

How to prepare

Preparation for a barium enema begins three days before the procedure:

  • Day 1:
    • Breakfast: strained orange juice
    • Lunch: consommé, grilled beef steak, and strained orange juice
    • Snack: 50 g of cooked ham
    • Dinner: French omelet and 50 g of cooked ham
  • Day 2:
    • Breakfast: tea or chamomile
    • Lunch: consommé, ¼ cooked chicken, strained orange juice
    • Snack: 50 g of cooked ham
    • Dinner: grilled fish and soft-boiled egg
  • Day 3:
    • Breakfast: 50 g of cooked ham
    • Lunch: consommé, grilled or boiled fish, strained orange juice
    • Dinner: consommé and French omelet
    • After dinner: administer two 250 cc cleansing enemas
  • Day of procedure:
    • For morning procedures: arrive fasting
    • For afternoon procedures: breakfast before 10:30 am (coffee with milk and biscuits), then no further food intake
    • Administer two additional 250 cc cleansing enemas