What is a MUGA scan?
An equilibrium radionuclide ventriculogram, also called a MUGA nuclear scan, is a noninvasive diagnostic test used to evaluate the pumping function of the ventricles (lower chambers of the heart). During the test, a small amount of radioactive tracer is injected into a vein. A special camera, called a gamma camera, detects the radiation released by the tracer to produce computer-generated movie images of the beating heart. The MUGA scan is a highly accurate test used to determine the heart’s pumping function.
How should I prepare for the test?
- There is no special preparation required for this test; there are no medication or food restrictions.
- Wear comfortable clothes that can be easily removed, as you may be asked to wear a hospital gown during the test.
What happens during the test?
- First, a nuclear medicine technologist injects a small amount of stannous chloride into a vein in your arm. This substance prepares your red blood cells for a second injection of a radioactive solution 30 minutes later. This combination of injections “tags” your red blood cells with a radioactive tracer that can be detected by the camera.
- For the imaging part of the test, a technologist will attach three electrodes (small, round sticky patches) to the skin of your chest. Men may have their chest hair shaved to allow a better connection. The electrodes are attached to an electrocardiograph monitor (ECG) that charts your heart’s electrical activity during the test.
- The technologist will ask you to lie on the exam table under the gamma camera. The camera is focused on the heart and analyzes the amount of radio-labeled red blood cells pumped out of the heart with each heartbeat. This test calculates your ejection fraction, a measurement of how well your heart pumps with each beat.
- A normal ejection fraction ranges from 50-70%. An ejection fraction of 65%, for example, means that 65% of the total amount of blood in the left ventricle is pumped out with each heartbeat. The ejection fraction may be lower when the heart muscle has become damaged due to a heart attack, heart muscle disease (cardiomyopathy), or other causes.
Are there any side effects from the injections during the test?
The simple answer is no. Because the injected medications contain only a minimal amount of the carrier drug, there are no significant adverse or allergic reactions. The radioactive tracer used during the MUGA scan is a diagnostic dose of radiation that is similar to the dose you would receive during a CT scan and is not harmful.
How long will the test take?
The MUGA scan takes about one to two hours to perform.
What happens after the test?
You can resume your normal activities right after the test.
How will I get my test results?
After the cardiologist reviews your test, the results will go into your electronic medical record. Your referring physician will have access to the results and will contact you to discuss them.
