Occasionally Dr. Villa may want an accurate assessment of your heart function at rest only and not with stress. This is most commonly utilized for persons about to undergo chemotherapy treatment involving medications that may be toxic to the heart.
This test, known as a MUGA Scan or Radionuclide Angiogram (RNA), involves an injection of a small amount of imaging agent followed by a single resting scan. The scan is done primarily to determine the heart’s “ejection fraction,” which is a measure of the percentage of the heart’s pumping volume compared with its total volume of blood.
The MUGA Scan test is typically ordered for the following patients:
- With known or suspected coronary artery disease, to diagnose the disease and predict outcomes.
- With lesions in their heart valves.
- With congestive heart failure.
- Who have undergone percutaneous transluminal coronary angioplasty, coronary artery bypass graft surgery, or medical therapy, to assess the efficacy of the treatment.
- With low cardiac output after open-heart surgery.
- Who are undergoing cardiotoxic drug agents such as in chemotherapy e.g., with doxorubicin or immunotherapy (herceptin).
- Who have had a cardiac transplant.
How should I prepare for the MUGA Scan 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 MUGA Scan test?
- A technician will attach electrodes (small, round adhesive 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 (EKG) that charts your heart’s electrical activity during the test.
- An intravenous (IV) line will be inserted into a vein in your arm.
- The technician will ask you to lie on the exam table under the gamma camera. A nuclear imaging technician will draw a small amount of blood, combine it with a radioactive tracer, and inject the mixture into your IV. The radioactive tracer tags your red blood cells, so they can be detected by the camera. The tracer stays in your bloodstream for several hours and does not enter your tissue cells.
- The camera above the table is focused on the heart and analyzes the amount of radio-labeled red blood cells pumped from the heart with each heartbeat. Several images can be taken to look at you different walls of the heart.
- 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 percent. An ejection fraction of 65 percent, for example, means that 65 percent 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.
Before the MUGA Scan test
On the day of your test, you should wear lightweight and comfortable clothing.
MUGA Scan test time
You should allow approximately 1 hour and 15 minutes for the entire test.
After the MUGA Scan test
After the procedure you may leave without restrictions. There are no after-effects from the procedure and no risks or complications associated with a MUGA scan. A Nuclear Cardiologist and a Radiologist will interpret the scan and report their findings to your primary care doctor.