Colonoscopy is usually the preferred test to examine the digestive tract. However, there are several commonly performed X-ray tests that allow your doctor to examine your digestive tract from the esophagus to the rectum.
These tests utilize barium or an iodine-containing agent that allows visualization of the digestive tract and a form of X-ray machine called fluoroscopy. Fluoroscopy allows part of the body to be studied in motion and recorded on a video monitor.
Fluoroscopic examinations of your GI tract may be performed in a doctor's office, a commercial X-ray facility, or a hospital. These tests are called an "upper GI" or "lower GI," depending on the organs being examined.
Upper GI Tests
Upper GI tests use X-rays to examine the esophagus, stomach, and first part of the small intestine (the duodenum).
For these tests, you need to drink barium. As the barium passes through the digestive tract, it fills and coats the esophagus, stomach, and first part of the small intestine, making them more visible with X-ray. Then a fluoroscope machine is held over the part of the body being examined and transmits continuous images to a video monitor.