An<unk> , also called a barium swallow, barium study, or barium meal, is a series of radiographs used to examine the<unk>  tract for abnormalities. A contrast medium, usually a radiocontrast agent such as barium sulfate mixed with water, is ingested or instilled into the<unk>  tract, and X-rays are used to create radiographs of the regions of interest. The barium enhances the visibility of the relevant parts of the<unk>  tract by coating the inside wall of the tract and appearing white on the film. This in combination with other plain radiographs allows for the imaging of parts of the<unk><unk>  tract such as the pharynx, larynx, esophagus, stomach, and small intestine such that the inside wall lining, size, shape, contour, and patency are visible to the examiner. With fluoroscopy, it is also possible to visualize the functional movement of examined organs such as swallowing, peristalsis, or sphincter closure. Depending on the organs to be examined, barium radiographs can be classified into "barium swallow", "barium meal", "barium follow-through", and "enteroclysis" ("small bowel enema"). To further enhance the quality of images, air or gas is sometimes introduced into the<unk>  tract in addition to barium, and this procedure is called double-contrast imaging. In this case the gas is referred to as the negative contrast medium. Traditionally the images produced with barium contrast are made with plain-film radiography, but computed tomography is also used in combination with barium contrast, in which case the procedure is called "CT enterography".
Upper gastrointestinal series
Lower gastrointestinal series
Electrogastrogram
Capsule endoscopy
Magnetogastrography
GI cocktail
Gastric emptying scan
Enteroscopy