Gastric Emptying Study

What is a gastric emptying study?

A gastric emptying study is a medical test that tracks how long it takes a meal (or drink) to move through your stomach and empty from it. The coordinated passage of food and liquids through your stomach is called your gastric motility. Healthcare providers test your gastric motility to find out if it’s working normally. If it’s faster or slower than normal, your stomach may have a medical condition.

The most common method for testing gastric motility is called gastric emptying scintigraphy (GES). This is what most healthcare providers mean when they suggest a gastric emptying study. Gastric emptying scintigraphy is a type of nuclear medicine imaging test. It produces images by scanning radiation in your body. To make your stomach show up in the scan, you’ll ingest a meal with a radioactive tracer in it.

Other types of gastric emptying studies include:

• Gastric motility breath test (GEBT). A breath test can track the progress of a meal through your digestive system by measuring gases in your breath. For this test, you consume a special meal containing a carbon molecule (carbon-13) that produces a specific, measurable form of carbon dioxide (C02-13). This gas will be measurable in your breath after it reaches your intestines.
• SmartPill™ wireless motility capsule. For the SmartPill test, you swallow a pill-sized wireless electronic device. The device sends data to a receiver that you wear on your body as it travels through your digestive system. After a day or two, the SmartPill will pass out of your body in your poop. You’ll return the receiver to your healthcare provider, who will read the data.

What does a gastric emptying study tell you?

The study tells you if your stomach is emptying too fast or too slow. It can also show where in your stomach things are moving faster or slower, and which parts are involved. This can begin to explain some of the gastrointestinal (GI) symptoms you might be having. A healthcare provider might suggest a gastric emptying study if you’ve been experiencing certain symptoms after eating, such as:

• Feeling full very quickly and/or for a long time after.
• Frequent nausea and/or vomiting.
• Upper abdominal pain.
• Abdominal bloating and/or distension.
• Loss of appetite and weight loss.
• Noticeable blood sugar spikes and crashes.
• Dizzy spells.
• Heart rate accelerations.
• Indigestion.
• Chronic acid reflux.

What conditions does a gastric emptying study diagnose?

Slow gastric emptying may be a sign of an obstruction in your stomach, or stomach paralysis (gastroparesis). Gastroparesis is a problem with your stomach muscles and nerves. Fast gastric emptying, or dumping syndrome, is also related to your muscles and nerves. It’s a common side effect of stomach surgery, but if you haven’t had surgery, it might point to another underlying condition.

How does gastric emptying scintigraphy work?

The nuclear imaging test works by scanning a radioactive tracer as it moves through your stomach. Some healthcare providers describe scintigraphy as an “inside-out X-ray”. Instead of passing radiation through your body from the outside, a radioactive tracer emits gamma rays from inside you. Then, like an X-ray, a gamma camera detects the radiation and processes it into two-dimensional images.

To see how a solid meal progresses through your stomach, a healthcare provider adds the radioactive tracer to a meal that you’ll consume before the test. It’s a standardized meal, the same for everyone, with precise amounts of fiber, sugar, protein and fat, which all affect your gastric motility. The standard radioactive isotope they use is sulfur colloid (99mTc), which has a very low risk of toxicity.

What happens before a gastric emptying study?

You’ll discuss the test with your healthcare provider in advance. They’ll want to know what health conditions you have and what medications you’re taking, which can affect how the test works for you.

You may not be a good candidate for the test if you’re prone to hyperglycemia or hypoglycemia. You should also avoid the test if you’re pregnant or breastfeeding (chestfeeding) because of the radiation exposure.

If you have a menstrual cycle, they might want to schedule your test at a certain point in your cycle to avoid the effects of hormone fluctuations, which can affect gastric emptying and skew your results.

How should I prepare for the gastric emptying study?

You’ll need to have an empty stomach for the test. Your healthcare provider will ask you not to eat or drink at least four hours beforehand. They’ll typically schedule your test in the morning, so you can fast overnight.

If you have diabetes and use insulin, they’ll ask you to bring it and your glucose monitor with you. They’ll check your blood glucose levels before the test, record them and adjust them with insulin, if necessary.

You shouldn’t smoke before the test, which can delay gastric emptying. You may also need to discontinue certain medications a few days before the test, including:

• Blood thinners.
• Opioids.
• Antidepressants.
• Calcium channel blockers.
• Acid-blocking medications.
• Feminizing hormone therapy.

What happens during the procedure?

1. First, you’ll eat your specially prepared meal: scrambled egg whites with sulfur colloid mixed in, toast with strawberry jelly and a cup of water. It’s important to eat it all within ten minutes or less.
2. You’ll stand for the test, if possible, or you can lie down. Your technician will aim the camera or cameras at your stomach. The scanner will scan your stomach for about a minute at a time, four or five times.
3. The first scan is right after you eat. If your technician suspects you have rapid gastric emptying, they’ll scan again 30 minutes later. The other checkpoints are at one hour, two hours and four hours later.
4. You can get up and leave the room in between scans, as long as you’re back on time.

How long does a gastric emptying study take?

A gastric emptying nuclear scan takes between two and four hours. Two hours is as long as it takes for the average stomach to empty. If your stomach empties completely within that time, they’ll stop scanning at that point. But if it takes longer, they’ll continue scanning for up to four hours.

Is it painful or uncomfortable?

You won’t feel the scan or notice the radiation at all. The radioactive tracer is undetectable in your food.

What is a gastric emptying liquid study?

A liquid emptying study can provide additional information about your condition. Liquids move through your stomach differently than solids, and you can have a different result from this test. Your healthcare provider may order a liquid emptying study together with your solid emptying study, or they may order it afterward as a follow-up test.

For this shorter test, you drink a cup of water tagged with sulfur colloid. A technician takes three sets of images over an hour-long session.

What are the risks or side effects of gastric emptying scintigraphy?

The small dose of radiation you’ll ingest isn’t enough to harm you. If you’re pregnant, there’s a small risk of harm to the fetus. If you’re lactating, a small amount of radiation may leak into your milk. These are reasons to postpone the test. Otherwise, there are no known side effects. The radiation will pass out of your body through your pee and poop over the next two days. Drink plenty of water to help it along.

How do I interpret my gastric emptying study results?

Your healthcare provider will read your test results and discuss them with you. Your results will show how long it took for the meal you ate to travel through your stomach. They’ll show its progress at the one-hour, two-hour and four-hour marks. They’ll compare those results against the normal range. If your results are faster or slower than the normal range, it indicates fast or slow gastric emptying.

Normal results

• 30 minutes: At least 70% of the meal is still in your stomach.
• One hour: At least 30% of the meal is still in your stomach, and at least 10% has emptied.
• Two hours: At least 40% of the meal has emptied.
• Four hours: At least 90% of the meal has emptied.

The normal range for the liquid emptying test is 20 to 25 minutes.

Abnormal results

You might have gastroparesis if:

• More than 60% of the meal is still in your stomach after two hours.
• More than 10% of the meal is still in your stomach after four hours.

You might have dumping syndrome (rapid gastric emptying) if:

• More than 30% of the meal has already emptied after 30 minutes.
• More than 70% of the meal has already emptied after an hour.