Multiple-Gated Acquisition (MUGA)
The multiple-gated acquisition (MUGA) scan, also called a cardiac blood pool study, is a non-invasive nuclear medicine test that enables clinicians to obtain information about heart muscle activity. The scan displays the distribution of a radioactive tracer in the heart. The images of the heart are obtained at intervals throughout the cardiac cycle, and are used to calculate ejection fraction (an important measure of heart performance) and evaluate regional myocardial wall motion.
A MUGA scan may be done while the patient is at rest. The resting study is usually performed to obtain the ejection fraction of the right and left ventricles, evaluate the left ventricular regional wall motion, assess the effects of cardiotoxic drugs (i.e., chemotherapy), and differentiate the cause of shortness of breath (pulmonary vs. cardiac).
The MUGA scan is a series of images that demonstrate the flow of blood through the heart, providing information about heart muscle activity. Before images are taken, a radionuclide is injected into the bloodstream, a process that requires two injections. The first injection contains a chemical that adheres to red blood cells, and the second contains a radioactive tracer (Tc99m) that attaches to that chemical. The test takes about 1 hour to complete. No special preparation is required.