Computed tomography (CT) scans create detailed cross-sectional images of the body. While a standard CT scan provides valuable information, certain situations require a special liquid, known as a contrast agent, to enhance image clarity. This helps medical professionals better visualize specific organs and tissues, aiding in accurate diagnoses by highlighting areas that would otherwise appear indistinct.
Understanding Barium and its Purpose
Barium sulfate is a metallic compound used as an oral contrast agent during CT scans, particularly for examining the gastrointestinal (GI) tract. It is insoluble in water, meaning it is not absorbed into the bloodstream or body tissues.
When consumed, barium sulfate coats the inner lining of the esophagus, stomach, and intestines. Barium has a high atomic number, allowing it to absorb X-rays, making the barium-coated GI tract clearly visible as a bright white outline on the CT images. This helps radiologists distinguish the digestive organs from surrounding soft tissues and identify abnormalities such as inflammation, blockages, or abnormal growths.
What to Expect During Your Appointment
Preparation for a CT scan involving oral barium typically includes fasting for several hours before your appointment, often four hours, though clear liquids are usually permitted up to two hours prior. You will receive specific instructions regarding the timing and amount of barium to drink, which usually involves consuming multiple doses over a period leading up to the scan, such as 60 to 90 minutes before, and then another dose immediately prior.
The barium liquid has a chalky texture and can be unappealing in taste. During the scan, you will lie on a table that slides into the CT scanner. The technologist will provide breathing instructions, and it is important to remain still to ensure clear images. After the scan, you should drink plenty of fluids to help flush the barium out of your system.
Safety Information and Common Side Effects
Barium sulfate is generally considered safe for use as a contrast agent because it is not absorbed into the body. However, some common and mild side effects can occur, including constipation, stomach cramps, nausea, or a chalky taste in the mouth. Increasing your fluid intake after the scan can help manage constipation, and a laxative may be recommended if needed. Your stool may appear lighter in color until all the barium has passed.
Serious complications are rare but can include allergic reactions, such as hives, itching, or difficulty breathing, which require immediate medical attention. In cases of suspected bowel perforation, barium can leak into the abdominal cavity, potentially leading to a serious condition called barium peritonitis. Aspiration of barium into the lungs, though uncommon, can also occur and may diminish lung capacity. If you experience severe abdominal pain, persistent vomiting, or an inability to have a bowel movement after the procedure, contact your doctor promptly.
When Barium Isn’t an Option
There are specific medical situations where barium sulfate may not be suitable, necessitating the use of alternative contrast agents. Conditions such as suspected bowel perforation, severe constipation, recent surgery involving the GI tract, or a known allergy to barium components are contraindications. In these instances, using barium could lead to complications, such as leakage into the abdominal cavity or exacerbating a blockage.
Water-soluble iodine-based contrast agents are often used as alternatives because they are absorbed into the bloodstream and can be safely excreted by the kidneys if a perforation is present. While these alternatives may have a more bitter taste, they offer a safer option when the integrity of the GI tract is questionable. In some limited research settings, whole milk has even been explored as a low-attenuation alternative, particularly for its comparable effectiveness in bowel distension and visualization.