Last updated: 11/24/2009

An upper GI series takes place in a hospital or clinic setting, and is performed by an x ray technologist and a radiologist. Before the test begins, the patient is sometimes given a glucagon injection, a medication that slows stomach and bowel activity,...

to provide the radiologist with a clear picture of the gastrointestinal tract. In order to further improve the upper GI picture clarity, the patient may be given a cup of fizzing crystals to swallow, which distends the esophagus and stomach by producing gas.

Once these preparatory steps are complete, the patient stands against an upright x ray table, and a fluoroscopic screen is placed in front of him or her. The patient will be asked to drink from a cup of flavored barium sulfate, a thick and chalky-tasting liquid, while the radiologist views the esophagus, stomach, and duodenum on the fluoroscopic screen. The patient will be asked to change positions frequently to coat the entire surface of the gastrointestinal tract with barium, move overlapping loops of bowel to isolate each segment, and provide multiple views of each segment. The technician or radiologist may press on the patient's abdomen to spread the barium throughout the folds within the lining of the stomach. The x ray table will also be moved several times throughout the procedure. The radiologist will ask the patient to hold his or her breath periodically while exposures are taken. After the radiologist completes his or her portion of the exam, the technologist takes three to six additional films of the GI tract. The entire procedure takes approximately 15–30 minutes.

In addition to the standard upper GI series, a physician may request a detailed small bowel follow-through (SBFT), which is a timed series of films. After the preliminary upper GI series is complete, the patient will drink additional barium sulfate, and will be escorted to a waiting area while the barium moves through the small intestines. X rays are initially taken at 15-minute intervals until the barium reaches the colon (the only way to be sure the terminal ileum is fully seen is to see the colon or ileocecal valve). The interval may be increased to 30 minutes, or even one hour if the barium passes slowly. Then the radiologist will obtain additional views of the terminal ileum (the most distal segment of the small bowel, just before the colon). This procedure can take from one to four hours.

Esophageal radiography, also called a barium esophagram or a barium swallow, is a study of the esophagus only, and is usually performed as part of the upper GI series (sometimes only a barium swallow is done). It is commonly used to diagnose the cause of difficulty in swallowing (dysphagia), and to detect a hiatal hernia. The patient drinks a barium sulfate liquid, and sometimes eats barium-coated food while the radiologist examines the swallowing mechanism on a fluoroscopic screen. The test takes approximately 30 minutes.