What is a Gastric Emptying Study?
A gastric emptying study (also called a gastric transit scan) is a specialized imaging test that measures how quickly food empties from your stomach into your small intestine. This test helps diagnose conditions that cause your stomach to empty too quickly or too slowly.
Your stomach normally empties food at a certain rate. When this process is too slow (delayed gastric emptying or gastroparesis) or too fast (rapid gastric emptying or dumping syndrome), it can cause various digestive symptoms and affect how your body absorbs nutrients and medications.
Why Might I Need This Test?
Your doctor may recommend a gastric emptying study if you have symptoms such as:
- Persistent nausea or vomiting
- Feeling full quickly when eating
- Upper abdominal pain or discomfort
- Bloating after meals
- Heartburn that doesn’t respond to treatment
- Unexplained weight loss
- Fluctuating blood sugar levels (especially in diabetes)
- Diarrhea shortly after eating
This test can help diagnose conditions such as:
- Gastroparesis (delayed stomach emptying)
- Dumping syndrome (rapid stomach emptying)
- Functional dyspepsia
- Complications from diabetes affecting the digestive system
- Effects of certain medications on stomach function
- Evaluation before or after certain stomach surgeries
How Does the Test Work?
The test works by:
- You eat a meal that contains a small amount of radioactive material (Tc-99m pertechnetate)
- This material is harmless and allows the food to be tracked by a special camera
- As you digest the meal, a gamma camera takes pictures of your stomach
- These images show how quickly the food moves from your stomach into your small intestine
- The results are calculated as the percentage of food that empties from your stomach over time
- This is compared to normal emptying rates to determine if yours is too slow or too fast
Preparing for Your Gastric Emptying Study
- You will need to fast for at least 6-8 hours before the test (typically overnight)
- Do not eat or drink anything after midnight the night before your test
- Inform your doctor about all medications you’re taking
- Some medications may need to be temporarily stopped as they can affect stomach emptying:
- Prokinetic medications (medicines that increase stomach motility)
- Pain medications, particularly opioids
- Some antidepressants
- Anticholinergic medications
- Do not smoke for at least 24 hours before the test
- Avoid alcohol for at least 24 hours before the test
- If you have diabetes, ask your doctor how to manage your medication on the day of the test
What to Expect During the Procedure
The Test Meal
- You’ll be given a specific test meal to eat, which typically includes:
- A sandwich with egg (the egg whites contain the radioactive tracer)
- A glass of water (approximately 200ml)
- You’ll need to eat the entire meal within about 10 minutes
- The meal is designed to be easy to digest and is generally well-tolerated
- For some patients, a liquid-only study may be performed using water labeled with the radioactive tracer
The Imaging Process
- Immediately after finishing the meal, initial images will be taken to confirm all the food is in your stomach
- You’ll lie on an examination table while a gamma camera takes pictures of your abdomen
- Images will be taken at regular intervals (typically every 15-30 minutes) for about 90 minutes
- You’ll need to lie still during each imaging session, which takes only a few minutes
- Between images, you may be asked to sit in a waiting area
- You should not eat or drink anything during the test period
- In some cases, additional images may be taken at 2, 3, or 4 hours after the meal
After Your Gastric Emptying Study
- You can resume your normal diet and activities immediately after the test
- Continue taking any medications that were temporarily stopped, unless instructed otherwise
- The small amount of radiation from the test meal will naturally leave your body within a few days
- A nuclear medicine specialist will analyze your results and send a report to your doctor
- Your doctor will discuss the results with you at your follow-up appointment
What Do the Results Mean?
- Normal gastric emptying: Approximately half of the test meal should leave your stomach within 90-120 minutes
- Delayed gastric emptying (gastroparesis): Food stays in your stomach longer than normal
- Rapid gastric emptying (dumping syndrome): Food leaves your stomach faster than normal
Your doctor will interpret these results in the context of your symptoms and medical history to determine the best treatment approach.
Are There Any Risks?
The gastric emptying study uses a very small amount of radiation. The benefits of the diagnostic information gained from the test far outweigh any potential risks from this minimal radiation exposure. There are no known side effects from the test meal or the imaging procedure.
How Long Will the Entire Procedure Take?
The standard procedure takes approximately 2 hours:
- Initial preparation and meal consumption: 15-20 minutes
- Standard imaging period: 90 minutes
- In some cases, additional images may extend the test to 4 hours
If you have any questions or concerns about your gastric emptying study, please discuss them with your healthcare provider.
