Definition

A series of x-ray pictures of the upper gastrointestinal (GI) tract, including the throat, esophagus, stomach, and the first part of the small intestine (duodenum). The x-ray pictures are taken after the patient drinks a liquid that contains barium sulfate (a silver-white metallic compound). The barium sulfate coats and outlines the inner walls of the upper GI tract so they can be seen on the x-ray pictures. Also called barium swallow and upper gastrointestinal series.