Upper Gastrointestinal Series

(UGI, Upper GI Series, GI Series, Upper Gastrointestinal Tract X-ray)

Procedure Overview

What is an upper gastrointestinal series?

An upper gastrointestinal series (UGI) is a radiographic (x-ray) examination of the upper gastrointestinal (GI) tract. The esophagus, stomach, and duodenum (first part of the small intestine) are made visible on x-ray film by a liquid suspension. This liquid suspension may be barium or a water-soluble contrast such as GastrografinTM. If only the pharynx (back of mouth and throat) and esophagus (hollow tube of muscle extending from below the tongue to the stomach) are examined with barium, the procedure is called a barium swallow. If the water-soluble contrast is used, the procedure is called a Gastrografin swallow.

X-rays use invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs on film. X-rays are made by using external radiation to produce images of the body, its organs, and other internal structures for diagnostic purposes. X-rays pass through body tissues onto specially-treated plates (similar to camera film) and a “negative” type picture is made (the more solid a structure is, the whiter it appears on the film).

Fluoroscopy is often used during an upper GI series. Fluoroscopy is a study of moving body structures - similar to an x-ray “movie.” A continuous x-ray beam is passed through the body part being examined, and is transmitted to a TV-like monitor so that the body part and its motion can be seen in detail. In an upper GI series, fluoroscopy allows the radiologist to see the movement of the barium through the esophagus, stomach, and duodenum as a person drinks it.

Why is barium used with x-rays?

Barium is a dry, white, chalky, metallic powder that is mixed with water to make a thick milkshake-like drink. Barium is an x-ray absorber and appears white on x-ray film. When swallowed, a barium drink coats the inside walls of the upper GI tract organs so that the swallowing motion, inside wall lining, function, size, and shape of these organs are visible on x-ray. This process shows differences that might not be seen on standard x-rays. Barium is used only for diagnostic studies of the GI tract.

The use of barium with standard x-rays contributes to the visibility of various characteristics of the esophagus, stomach, and duodenum. Some abnormalities of the upper GI tract that may be detected with an upper GI series include tumors, ulcers, hernias, diverticula (pouches), strictures (narrowing), inflammation, and swallowing difficulties.

In addition to barium, the radiologist may use a gas, such as air or a carbonated substance. You may be given a powder, tablet, or carbonated beverage that produces gas when swallowed. Alternately, you may drink the barium through a perforated straw so that you swallow air with the barium. Air or gas will appear black on x-ray film, contrasting with the barium’s white image. The use of the two substances, barium and gas, is called a double contrast study. The radiologist may use the water-soluble contrast if you have a perforation (tear or hole) of the bowel or esophagus, or for other reasons determined by your physician.

The purpose of using two contrast substances is to achieve an enhancement of the inside wall lining of the esophagus, stomach, and duodenum. As the gas expands the organs (like blowing up a balloon), a barium coating is formed on the inner surface of the organs. This technique enhances visualization by sharpening the outline of the inner surface layer of the esophagus, stomach, and/or duodenum, and is useful in diagnosing structural and tissue abnormalities.

Other related procedures that may be used to diagnose upper GI problems are barium swallow and esophagogastroduodenoscopy (EGD). Please see these procedures for additional information.

About the upper GI tract:

Illustration of the anatomy of the digestive system, adult
Click Image to Enlarge

Digestion is the process by which food and liquid are broken down into smaller parts so that the body can use them to build and nourish cells, and to provide energy. Digestion begins in the mouth, where food and liquids are taken in, and is completed in the small intestine.

Digestion involves the mixing of food, the movement of food through the digestive tract, and the chemical breakdown of large molecules of food into smaller molecules.

In a wave-like movement, called peristalsis, muscles propel food and liquid along the digestive tract. The involvement of the upper GI tract includes the following:

  • The first major muscle movement is swallowing food or liquid. The start of swallowing is voluntary, but once it begins the process becomes involuntary and continues under the control of the nerves.
  • The esophagus, which connects the throat above with the stomach below, is the first organ into which the swallowed food goes.
  • Where the esophagus and stomach join, there is a ring-like valve that closes the passage between the two organs. As food nears the valve, the surrounding muscles relax and allow food to pass into the stomach. The valve then closes.
  • Once food has entered the stomach, it is stored and mixed and then emptied into the small intestine.
  • The food is digested in the small intestine and dissolved by the juices from the pancreas, liver, and intestine and the contents of the intestine are mixed and pushed forward to allow further digestion.

Reasons for the Procedure

An upper GI series may be performed to diagnose structural or functional abnormalities of the esophagus, stomach, and duodenum. These abnormalities may include, but are not limited, to the following:

  • ulcers - gastric (stomach) or peptic (duodenum)
  • gastroesophageal reflux disease (GERD)
  • inflammation (esophagitis, gastritis, or duodenitis) or infection
  • benign tumors (nonmalignant)
  • cancer
  • structural problems, such as diverticula, strictures, or polyps (growths)
  • hiatal hernia - upward movement of the stomach, either into or alongside the esophagus
  • dysphagia (difficulty swallowing)
  • motility disorders (difficulty moving foods through the pharynx or esophagus)
  • chest and/or abdominal pain
  • unexplained vomiting and/or indigestion
  • bloody bowel movements 

There may be other reasons for your physician to recommend an upper GI series.

Risks of the Procedure

You may want to ask your physician about the amount of radiation used during the procedure and the risks related to your particular situation. It is a good idea to keep a record of your past history of radiation exposure, such as previous scans and other types of x-rays, so that you can inform your physician. Risks associated with radiation exposure may be related to the cumulative number of x-ray examinations and/or treatments over a long period of time.

If you are pregnant or suspect that you may be pregnant, you should notify your physician. Radiation exposure during pregnancy may lead to birth defects.

Patients who are allergic to or sensitive to medications, contrast dyes, iodine, shellfish, or latex should notify their physician.

Constipation or fecal impaction may occur if the barium is not completely eliminated from the body.

Contraindications for an upper GI series include, but are not limited to, the following:

  • bowel or esophagus perforation
  • bowel obstruction or severe constipation
  • pregnancy
  • severe swallowing difficulty such that aspiration (entry of substances into the lungs) of barium is likely

There may be other risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.

Certain factors or conditions may interfere with the accuracy of an upper GI series. A recent barium x-ray or cholangiography procedure may interfere with the x-ray exposure of the upper GI area.

Before the Procedure

  • Your physician will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.
  • You may be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully and ask questions if something is not clear.
  • You will be asked to not eat or drink liquids for eight hours before the procedure, generally after midnight. In addition, if you smoke, you should refrain from smoking after midnight.
  • If you are pregnant or suspect that you may be pregnant, you should notify your physician.
  • Notify your physician if you are sensitive to or are allergic to any medications, latex, tape, and anesthetic agents (local and general).
  • Notify your physician of all medications (prescribed and over-the-counter) and herbal supplements that you are taking. Your physician may advise you to withhold certain medications prior to the procedure.
  • Notify the radiologist if you have had a recent barium or contrast x-ray or cholangiography procedure, as this may interfere with obtaining an optimal x-ray exposure of the upper GI area.
  • Based upon your medical condition, your physician may request other specific preparation.

During the Procedure

An upper GI series may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary, depending on your condition and your physician’s practices.

Generally, an upper GI series follows this process:

  1. You will be asked to remove any clothing, jewelry, or other objects that may interfere with the procedure.
  2. If you are asked to remove clothing, you will be given a gown to wear.
  3. You will be positioned on an x-ray table that can tilt you from a horizontal to an upright position. You may be asked to change positions (e.g., lying on your side, back, or stomach) at intervals during the procedure.
  4. Standard x-rays of the heart, lung, and abdomen may be performed first.
  5. The radiologist will ask you to take a swallow of a thickened contrast drink. The contrast is usually flavored, although it may not be very pleasant tasting.
  6. As you swallow the contrast, the radiologist will take single pictures, a series of x-rays, or a video (fluoroscopy) to observe the contrast moving through the pharynx.
  7. If you are having a procedure with barium, you will be given a thinner barium drink to swallow. X-rays and/or fluoroscopy will be used to observe the barium’s passage down the esophagus. You may also be asked to swallow a barium “marshmallow” - a small piece of barium-soaked bread, which can help to visualize certain structural problems of the esophagus.
  8. The radiologist may also press on your abdomen during the examination. This may help to visualize the stomach as well as aid in proper coating of the stomach wall.
  9. If you are to have a double contrast study, you may be asked to swallow a powder, tablet, or carbonated beverage. Alternately, you may be asked to drink the barium through a perforated straw. Because the gas that is produced will expand and enhance the visualization of the inner surface of the upper GI organs, it will be important not to burp.
  10. Once all required x-rays have been taken, you will be assisted from the table.

After the Procedure

You may resume your normal diet and activities after an upper GI series, unless your physician advises you differently.

Barium may cause constipation or possible impaction after the procedure if it is not completely eliminated from your body. You may be advised to drink plenty of fluids and eat foods high in fiber to expel the barium from the body. You may also be given a cathartic or laxative to help expel the barium.

Since barium is not absorbed into the body but passes through your entire gastrointestinal tract, your bowel movements may be lighter in color until all of the barium has been excreted.

Water-soluble contrast such as Gastrografin may cause nausea, vomiting, and/or diarrhea.

Notify your physician to report any of the following:

  • difficulty with bowel movements or inability to have a bowel movement
  • pain and/or distention of the abdomen
  • stools that are smaller in diameter than normal

Your physician may give you additional or alternate instructions after the procedure, depending on your particular situation.

Online Resources

The content provided here is for informational purposes only, and was not designed to diagnose or treat a health problem or disease, or replace the professional medical advice you receive from your physician. Please consult your physician with any questions or concerns you may have regarding your condition.

This page contains links to other Web sites with information about this procedure and related health conditions. We hope you find these sites helpful. But please remember we do not control or endorse the information presented on these Web sites, nor do these sites endorse the information contained here.

American Cancer Society

American Gastroenterological Association

National Cancer Institute (NCI)

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

National Institutes of Health (NIH)

National Library of Medicine

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