X-rays often are used to evaluate digestive problems. Standard x-rays (plain x-rays) do not require any special preparation (see Plain X-Rays). These x-rays usually can show a blockage or paralysis of the digestive tract, or abnormal air patterns in the abdominal cavity. Standard x-rays can also show enlargement of the liver, kidneys, and spleen.
X-ray studies using barium often provide more information than standard x-rays. X-rays are taken after a person swallows barium in a flavored liquid mixture or as barium-coated food. The barium looks white on x-rays and outlines the digestive tract, showing the contours and lining of the esophagus (the hollow tube that leads from the throat to the stomach), stomach, and small intestine. Barium may collect in abnormal areas, showing ulcers, tumors, blockages, and erosions and enlarged, dilated esophageal veins.
X-rays may be taken at intervals to determine where the barium is. In a continuous x-ray technique called fluoroscopy, the barium is observed as it moves through the digestive tract. With this technique, doctors can see how the esophagus and stomach function, determine whether their contractions are normal, and tell whether food is getting blocked.
Barium also can be given in an enema to outline the lower part of the large intestine. Barium also can be given through a thin tube that is passed through the nose, down into the stomach, and then into the small intestine (enteroclysis). With a barium enema or enteroclysis, x-rays can show polyps, tumors, or other structural abnormalities. This procedure may cause crampy pain or slight to moderate discomfort.
Barium taken by mouth or as an enema is eventually passed in the stool, making the stool chalky white. Because barium can cause significant constipation, the doctor may give a gentle laxative to speed up the elimination of barium.