A barium meal, also known as an upper gastrointestinal series is a procedure in which radiographs of the oesophagus, stomach and duodenum are taken after barium sulfate is ingested by a patient. Barium meals are useful in the diagnosis of structural and motility abnormalities of the foregut.
The gastrointestinal tract, like other soft-tissue structures, does not show clearly enough for diagnostic purposes on plain radiographs. Barium salts are radioopaque: they show clearly on a radiograph. If barium is swallowed before radiographs are taken, the barium within the oesophagus, stomach or duodenum shows the shape of the lumina of these organs.
Liquid suspensions of barium sulfate are non-toxic, apart from a small risk of producing a disturbance in bowel function for 48 hours after ingestion. They usually have a chalky taste that can be disguised by adding flavours.
A barium meal usually takes less than an hour. The patient ingests gas pellets and citric acid to expand the stomach. Then about 3 cups (about 709 ml) of barium is ingested. The patient may move or roll over to coat the stomach and oesophagus in barium. A needle may also be used to relax the muscle between the stomach and the duodenum. Following these preparations, an x-ray is taken.
There are two varieties of barium meal: single and double contrast meals. A single contrast meal uses only barium, a radioopaque (or positive) contrast medium, to image the upper gastrointestinal tract. A double contrast meal uses barium as well as a radiolucent (or negative) contrast medium such as air, nitrogen, or carbon dioxide. The double contrast meal is more useful as a diagnostic test, demonstrating mucosal details and allowing the detection of small mucosal lesions such as diverticula or polyps.
The diagnostic usage of barium studies has declined in recent years with the increasing use of the practice of oesophagogastroduodenoscopy, which allows direct visual inspection of suspicious areas within the oesophagus, stomach and duodenum.