Heart & Vascular Hospital

202 S. Park Street
Madison, WI 53715
Telephone: (608) 417-6259
Location: Meriter Hospital - 10 Tower

Multi-Gated Acquisition (MUGA) Scan


What is a MUGA scan?

A MUGA (Multi-Gated Acquisition) scan is a nuclear medicine scan used to see how the heart wall moves and how much blood is expelled with each heart beat while the patient is at rest. The MUGA scan produces a moving image of the beating heart, and from this image several important features can be determined about the health of the heart's ventricles (the heart's major pumping chambers).

How is a MUGA scan performed?

The patient lies under a special camera (a gamma scintillation camera) that detects radiation. A protein tagged with a radioactive tracer (usually technetium-99m) is injected into the patient's forearm through an IV. (The level of radiation to which a patient is exposed during a MUGA scan is felt by experts to be minimal. It is in the same general range as the level of radiation received with a chest X-ray.) The camera works in coordination with an electrocardiogram (ECG) to take a picture at specific times in the cycle of heart contraction and relaxation. When data from many sequential pictures is processed by a computer, a doctor can analyze whether the left ventricle is functioning normally.

Where is a MUGA scan performed?

MUGA scans are performed in the hospital's nuclear radiology lab.

What can be learned from a MUGA scan?

Several important features of heart function can be measured using the MUGA scan. If a patient has had a heart attack, or any other disease that affects the heart muscle, the MUGA scan can localize the portion of the heart muscle that has sustained damage, and can assess the degree of damage. But more importantly, the MUGA scan gives an accurate and reproducible means of measuring and monitoring the ejection fraction of the cardiac ventricles.

The left ventricular ejection fraction (LVEF) is the most commonly used measure of overall heart function. The ejection fraction is the proportion of blood that is expelled from the ventricle with each heart beat. So, for example, if the left ventricle ejects 60% of its blood volume with each beat, the LVEF is 0.6. (A normal LVEF is 0.5 or greater.)

Since the MUGA scan is one of the most accurate ways to measure the hearts ejection fraction, it is ideal for detecting subtle changes in a patient's heart function over time. It is commonly used to follow a patient's heart function during the delivery of chemotherapy for cancer. Some chemotherapeutic agents can be quite toxic to heart muscle. By measuring the MUGA ejection fraction periodically during chemotherapy, oncologists can determine whether it is safe to continue with therapy.