What is the purpose of a barium enema (lower GI series)?

• A. To visualize the colon outlined by contrast to detect polyps, ulcers, tumors
• B. To measure the length of the colon
• C. To treat constipation by flushing stool
• D. To assess liver function

Answer: (A)

The test’s main idea is to visualize the colon by coating its lining with a radiopaque contrast so the inner surface can be seen clearly and abnormalities like polyps, ulcers, or tumors can be detected. A barium enema introduces barium sulfate into the large intestine through the rectum, and X-rays show the outline of the colon as the barium fills and coats the mucosa. In a double-contrast variation, air is added to distend the colon, enhancing mucosal detail and making small polyps easier to spot. This procedure isn’t used to measure the colon’s length, to treat constipation by flushing stool, or to assess liver function.