A gastric emptying study is a nuclear medicine test, meaning it uses small amounts of radiation. It is usually done in the Nuclear Medicine department of your hospital as an inpatient or outpatient test.
This article will go over why you may need this test, how a gastric emptying study is done, and what the results mean.
Purpose of Test
A gastric emptying scan may be ordered to help your healthcare provider determine the cause of a number of symptoms involving the digestive tract.
You might need to have a gastric emptying study done if you have:
Abdominal painNausea and vomitingFeeling full after eating only a small amount of foodFailure to gain weight (in children)Suspected gastroparesisSuspected rapid gastric emptying (food moves through your stomach too fast)
A gastric emptying study can also be used:
As prep for certain surgical procedures such as a colectomy To evaluate for gastroesophageal reflux disease (GERD) particularly reflux that has been unresponsive to therapy
Risks and Contraindications
Before having a gastric emptying scan, tell your healthcare provider about any food or medication allergies that you have. You will be instructed to stop eating and drinking for about four hours before the test. It is important that you follow these instructions to ensure accurate test results.
Medications
Some medications need to be stopped before a gastric emptying scan. For example, your provider may tell you not to take any medication that changes how your stomach processes food.
This list is not all-inclusive, but here are a few medications that should be discontinued before a gastric emptying study:
Metoclopramide Erythromycin Tegaserod Domperidone Narcotic pain relievers such as oxycodone, hydrocodone, morphine, and more Atropine Dicyclomine Loperamide Promethazine
Health Conditions
Having certain health conditions may mean you need different instructions for a gastric emptying scan. For example:
If you have diabetes and use insulin, you will be given instructions about managing your glucose levels on the day of the test. Your insulin dose might need to be adjusted. If you are menstruating woman, having the test done during days one to 10 of your monthly cycle may provide more accurate results because hormonal changes affect how fast the stomach normally empties.
Alternatives
If you can’t have a gastric emptying scan, your provider might recommend doing a different test instead. Alternatives to a gastric emptying study include:
Barium swallow test: For this test, you will drink a beverage that has a substance called barium in it. The substance is safe for you to drink and helps your insides “light up” on a special kind of X-ray. The test can be used to look for problems in your esophagus and stomach. Breath test: For this test, you will swallow a substance that will help show if you have H. pylori bacteria in your stomach. The substance has urea in it. When the urea gets into your stomach, it will react with any H. pylori bacteria and they will make carbon dioxide (CO2). When your breath is measured, your provider can see if there is CO2 in it. “Smart pill” or capsule test: For this test, you will swallow a little pill that has a camera inside it. As it moves through your digestive tract, it will take some pictures. Your provider can use it to see if you have certain problems in your stomach or intestines, like ulcers or narrow parts (strictures).
Gastric Emptying Study Prep
Your healthcare provider will give you instructions to follow before a gastric emptying test.
Before the test, you will have something to eat. If your provider orders solid food for you before your scan, the standard meal consists of scrambled egg whites, toast with jam, and a small glass of water.
The meal has to be the same so that the test results are accurate. The scrambled egg whites contain a radioactive isotope called Technetium-99m Sulfur Colloid which is tasteless. If possible, this meal should be eaten within a time period of 10 minutes.
Children
If your child is having a gastric emptying scan you will want to simply explain what will happen to them beforehand to help alleviate any anxiety they may have. It can also be helpful to take a comfort item such as a favorite toy or a blanket with you on the day of the test.
Most children’s hospitals have staff on hand who specialize in relieving a child’s anxiety and discomfort during medical tests. Don’t hesitate to request these kinds of services when you arrive.
During the Test
After you finish eating, you will lie down on a table. Then, images of your abdomen will be taken with a special camera. The pictures are taken at various time intervals to see how much of the food has been eliminated from the stomach and how long it takes.
You may be allowed to leave the nuclear medicine department and return in time to have more images taken at these various times. This means that the whole gastric emptying test takes approximately four and a half to five hours.
Sometimes a liquid meal is ordered instead of a solid meal. This may be because of the specific condition that your healthcare provider is trying to diagnose with the test or simply because the test is being done on an infant or individual who normally consumes a liquid diet.
In this case, the test procedure is similar but the radioactive isotope is simply added to water, formula, or milk and the intervals that pictures are taken at are much closer together.
The overall time the test takes is typically much shorter when using a liquid diet than a solid diet (approximately one hour versus four hours or more).
After the Test
There are very few possible complications of a gastric emptying study that may affect your overall health. However, an allergic reaction is always possible (either to the meal or the radioactive isotope). The risk is mitigated by informing your medical team of any known allergies before the test.
Some individuals may be concerned about being exposed to radiation during this test since radiation exposure has been linked to cancer. The biggest factors that contribute to this risk are the amount of radiation you are exposed to, the length of time you are exposed to it, and how frequently you are exposed (having the test only one time versus having many tests or procedures that use radiation).
It is thought that infrequent low doses of radiation typically used for medical procedures pose minimal risk. A gastric emptying test, however, is not generally recommended for pregnant women because of the potential risk to the fetus. Breastfeeding women can have a gastric emptying study, but they are advised not to nurse for a brief period after the scan. The risk-to-benefit ratio should also be considered when giving the test to children. If you are concerned about radiation exposure, you should discuss it with your healthcare provider prior to scheduling a gastric emptying scan.
Gastric Emptying Study Results
Certain factors can limit how accurate gastric emptying study results are. These include poor blood sugar control if you are diabetic, not finishing your meal within the 10-minute time frame or not finishing the meal completely, and vomiting during the test.
How long it takes to get the results of a gastric emptying scan varies. A specialist called a radiologist generally interprets the images and then writes a report that is given to your healthcare provider.
When you get your results, you will see each time you had a picture taken throughout the test and a percentage. The percentage shows how much of the meal you ate before the test was still in your stomach each time an image was captured.
Normal gastric emptying study results are typically considered:
30 minutes: More than or equal to 70% of the meal is still in your stomachOne hour: 30% to 90% of the meal is still in your stomachTwo hours: Less than or equal to 60% of the meal is left in your stomachFour hours: Less than or equal to 10% of the meal is left in your stomach
If your results are different, it will mean that food either leaves your stomach faster or slower than normal. Your provider will look at how much food was left in your stomach each time to see how far from the normal results your results are. This will help them figure out what might be causing your symptoms.
For example, if your stomach empties more slowly than usual, you might have a condition called gastroparesis. If it empties too fast, you could have a condition called dumping syndrome.
Summary
A gastric emptying study can be used to diagnose digestive conditions. The test involves eating a meal that has a special substance in it called barium that helps the organs show up better on an imaging scan.
The pictures show how long it takes for food to move out of the stomach. Some conditions cause the stomach to empty too slowly and others cause it to empty too fast.
Providers can use a gastric emptying study to diagnose conditions like gastroparesis and dumping syndrome.
