Normal barium swallow exam. Interactive version.
A barium swallow (or esophagography) is a medical imaging procedure used to examine the upper GI (gastrointestinal) tract, which includes the esophagus and, to a lesser extent, the stomach.
Barium sulfate is a type of contrast medium that is opaque to X-rays. As the patient swallows the barium suspension, it coats the esophagus with a thin layer of the barium. This enables the hollow structure to be imaged.
This is commonly used with baking soda (sodium bicarbonate crystals) to produce gas (see Reactions of sodium bicarbonate). As gas is low in density, and the X-rays pass through very easily, they will appear as white patches, as opposed to the black produced by relatively dense, X-ray opaque barium. As such, it is extremely useful in providing a contrast to the barium, to produce a double contrast image, to allow better visualisation of the contrasting features within the mucosal layer of the esophagus.
Barium sulfate is an irritant outside the gastrointestinal tract. In cases where a leak is suspected or desired to be demonstrated, contrast imaging involving the use of water-soluble contrast media containing iodine is used.
As with all X-rays, the barium swallow technique employs radiation, and may irradiate the patient unnecessarily. The barium swallow should not be used unless required, and, although it cannot be replaced by endoscopy as for the barium enema, it should be avoided as much as possible for children and pregnant women.
The patient is asked to drink a suspension of barium sulfate. Fluoroscopy images are taken as the barium is swallowed. This is typically at a rate of 2 or 3 frames per second. The patient is asked to swallow the barium a number of times, whilst standing in different positions, i.e. AP, oblique and lateral, to assess the 3D structure as best as possible. This technique induces gas production in the esophagus, and can be uncomfortable to the subject.
Pathologies detected on a Barium Swallow include:
- Cancer of esophagus
- Tracheoesophageal fistula
- Schatzki ring
- Gastroesophageal reflux disease (GERD/GORD)
- Zenker's diverticulum
- Hiatus hernia
- Obstruction of esophagus
- Esophageal stricture
- Cancer of stomach
See also 
- Boon et al. Davidson's Principles & Practice of Medicine, 20th Edition, Chapter 22
- Harvard Health Publications — Diagnostic Tests — Barium Swallow
- Medline Plus Medical Encyclopedia