Gastrointestinal Nuclear Scans
In gastrointestinal nuclear scan, a small amount of radioactive material is introduced into your body, and a special camera records the movement and uptake of the radiotracer within different organs of the gastrointestinal (GI) tract. The resulting images provide information about these organs and the function of your digestive system. There are five common types of GI nuclear scans. In the gallbladder nuclear scan, GI bleeding scan, and liver-spleen scan, a radiotracer is injected into one of your veins. The gastroesophageal reflux scan and gastric emptying scan require ingesting a radiotracer orally.
Purpose of the Gastrointestinal Nuclear Scans
Gallbladder nuclear scan:
- To detect an acute infection of the gallbladder (cholecystitis), which can cause sudden, severe pain in the upper, right abdomen and jaundice (yellowed skin and/or eyes), a blocked bile duct, or signs of liver transplant rejection
- To detect gallbladder disease, including gallstones, tumors in the gallbladder or gallbladder defects
GI bleeding scan:
- To identify and locate active GI bleeding in patients with known or suspected intestinal blood loss
- To assess liver function; screen for liver metastases (cancer spread into surrounding tissues); detect tumors, cysts, and abscesses in the liver and spleen; or demonstrate enlargement of the liver or spleen
- To diagnose benign focal nodular hyperplasia (FNH)
Gastroesophageal reflux scan:
- To measure the emptying rate of the esophagus and detect gastroesophageal reflux (backflow of stomach acid into the esophagus) in people with persistent symptoms such as heartburn, regurgitation, or difficulty swallowing
Gastric emptying scan:
- To aid in the diagnosis of digestive disorders in people with symptoms that suggest delayed stomach emptying, such as unexplained nausea, vomiting, bloating, or early sensation of fullness. Possible causes include an obstruction (such as a peptic ulcer) and gastroparesis (a condition caused by nerve damage that primarily occurs in people with diabetes)
- To evaluate the speed at which food empties from the stomach and into the intestines or bowel
Who Performs Gastrointestinal Nuclear Scans
- A radiologist or a technician
Special Concerns about Gastrointestinal Nuclear Scans
- This test should not be performed in pregnant or breastfeeding women because of possible risks to the fetus or infant.
- Residual radioactive material from other recent nuclear imaging tests, such as a thyroid or bone scan, may interfere with the results.
- Movement during the test can interfere with the results.
- In the gastric emptying scan, eggs are usually used to hold the radiotracer. If you are allergic to eggs, notify your doctor. Another food can be substituted.
Before the Gastrointestinal Nuclear Scans
- Do not eat or drink anything for at least 2 hours before a gallbladder scan.
- Tell the radiologist or technologist if you are allergic to latex or shellfish or if you have an allergy or sensitivity to medications, contrast dyes, or iodine.
- Tell your doctor if you are pregnant or may be pregnant.
- Do not eat or drink anything after midnight on the day before a gastric emptying scan.
- No fasting is required for a liver-spleen scan or a GI bleeding scan.
- For a gastroesophageal reflux scan, you should eat a full meal just before the test.
- Remove any jewelry or metal objects before the test begins.
What You Experience during Gastrointestinal Nuclear Scans
- For the gallbladder, GI bleeding, and liver-spleen scans, a radiotracer is injected into a vein in your arm. (Other than the minor discomfort of this injection, the procedure is painless.)
- The gastric emptying scan requires eating a meal of scrambled eggs that has been mixed with a radiotracer, while for the gastroesophageal reflux scan, the radioactive material is ingested in a liquid mixture.
- You are placed in various positions under a large scanning camera, which detects the gamma rays being emitted by the radiotracer. You will be asked to remain still while the pictures are taken.
- The initial scans may take up to an hour. Scanning may then be repeated periodically to assess organ function. For example, to evaluate gastric emptying, sequential images of the stomach are obtained at 15- to 30-minute intervals over several hours. To detect GI bleeding, which is often intermittent, delayed films may be taken up to 24 hours after the initial scans.
Risks and Complications of Gastrointestinal Nuclear Scans
- The trace amount of radioactive material used in these tests is not associated with significant risks or complications.
- In extremely rare cases, patients may be hypersensitive to the radiotracer and may experience an adverse reaction.
After the Gastrointestinal Nuclear Scans
- You may resume your normal activities.
- Drink extra fluids to help your body eliminate the radioactive material.
- If the radiotracer was administered by injection, blood may collect and clot under the skin (hematoma) at the injection site; this is harmless and will resolve on its own. For a large hematoma that causes swelling and discomfort, apply ice initially; after 24 hours, use warm, moist compresses to help dissolve the clotted blood.
Results of Gastrointestinal Nuclear Scans
- A physician analyzes the recorded images for any abnormalities in the structure or function of the organ being examined.
- If a definitive diagnosis can be made, appropriate treatment will be initiated, depending on the specific problem.
- In some cases, additional tests may be needed for further evaluation of abnormal results.
The Johns Hopkins Consumer Guide to Medical Tests
Simeon Margolis, M.D., Ph.D., Medical Editor
Updated by Remedy Health Media