Radionuclide Angiogram/Multigated Acquisition Scan

Overview

A radionuclide angiogram/multigated acquisition (MUGA) scan is a test used to gather images of the heart throughout its pumping cycle. You may also hear it referred to as a blood pool scan. The test can help assess how well your heart is pumping by measuring the “ejection fraction,” the amount of blood pumped out of the heart’s two lower chambers (the ventricles). Generally, a healthy ejection fraction range is 50% to 70%. For example, the test can also be used to determine damage from a heart attack or chemotherapy.

What you can expect

A radionuclide angiogram/MUGA scan may be performed at rest or while you’re exercising to “stress” the heart. The process of a radionuclide angiogram involves the following:

The technician who’s performing the test will attach electrodes to your chest for an electrocardiogram (ECG, EKG) that will also take place during the scan.
You’ll be asked to lie down on an exam table under a gamma camera. If your test will be used to assess how well your heart functions when you’re exercising, you may be asked to lie on an exam table that has pedals at the end. Then, you’ll be asked to pedal with your feet while the images are being gathered. Or you may be asked to exercise on a treadmill or stationary bike.
A small amount of your blood will be drawn and mixed with a radioactive tracer (technetium-99m) that emits gamma rays into your bloodstream. The tracer “tags” red blood cells, making it possible to gather images of blood circulation in your heart. A gamma camera detects the gamma rays emitted by the tracer in your bloodstream.
After the gamma rays are converted into an electrical signal, they go to a computer, which creates an image of the chambers of your heart.

Risks

The radioactive chemicals used in typical doses for a radionuclide angiogram/MUGA scan are considered safe, as the chemicals leave the body quickly in the urine. However, as with X-rays and other types of radiation, gamma rays may affect an unborn child. Before your test, let your doctor know if you’re pregnant or may be pregnant.