A multiple-gated acquisition (MUGA) scan is an outpatient imaging test that looks at how well the bottom chambers of your heart (ventricles) are pumping blood out into your body.
This scan may also be called:
- equilibrium radionuclide angiogram
- blood pool scan
- radionuclide ventriculography (RVG or RNV)
- radionuclide angiography (RNA)
The MUGA scan uses a chemical compound called a tracer and an imaging device called a gamma camera to provide your doctor with images of your heart.
This scan is primarily used to see how much blood leaves your heart with each contraction, which is known as your ejection fraction. The results can help your doctor check for heart conditions if you’re experiencing abnormal heart-related symptoms.
The test is also often used to see if your heart is healthy enough for chemotherapy treatments for cancer. If this is the case, it’ll be performed before and during chemo treatments to keep an eye on your heart.
Let’s learn more about what exactly happens during a MUGA scan and how to understand what its results mean.
Here’s what you need to do to prepare for a MUGA scan:
- Stop taking any medications or using any supplements your doctor instructs you to stop.
- Don’t drink any caffeine or alcohol for a few hours before a resting scan that’s done while you’re sitting or lying down.
- Don’t eat or drink anything except water for a few hours before an exercise (stress) scan that’s done while you’re doing light activity.
- Wear loose, comfortable clothing and shoes.
- Let your doctor know if you’re pregnant, as the chemical tracer can harm the fetus.
Here’s how the procedure itself will likely go:
- Your doctor or a technician places small, circular objects called electrodes on your body. These electrodes are hooked up to an electrocardiograph (ECG or EKG) to measure your heart rate.
- If you’re doing a resting test, you’ll lie down on a table or special bed.
- An intravenous (IV) line is inserted into an arm vein.
- A medication is injected into your arm to increase your red blood cells’ ability to absorb the tracer material.
- The chemical tracer, known as a radionuclide, is injected into your arm through the IV line.
- A gamma camera is placed above your chest to capture various images of the heart from different angles so that every part is fully visible on the final images. The camera takes a picture every time your heart pumps blood so that your doctor can see how blood is pumping over time at the same stage in your heartbeat in each image.
- If you’re doing an exercise test, you’ll be asked to use a treadmill or cycling machine until your heart reaches its highest rate for typical exercise. Then, you’ll lie on a table to finish the scan. In some cases, you may cycle while lying down.
A MUGA scan takes about one to two hours.
You’ll be able to go home shortly after the test is done. Be sure to drink a lot of water to help flush the chemical tracer from your body. The tracer should be fully flushed out after two days.
There aren’t many risks associated with a MUGA scan. The level of radioactivity produced by the tracer material and the camera is extremely low and isn’t known to cause any short-term or long-term damage to your body. In fact, a MUGA scan produces less radioactivity than a typical X-ray scan.
It’s possible to have an allergic reaction to the radioactive tracer material. Symptoms can vary based on the type of tracer material used, and may include:
- feeling sick
- throwing up
- having diarrhea
- having an irregular heartbeat
- developing a rash or redness on skin
- experiencing visible swelling from fluid buildup (edema)
- feeling tired or disoriented
- passing out
You may also have trouble flushing out the tracer fluid if you have any kidney, liver, or heart conditions that require you to limit your fluid intake. Talk to your doctor before your test to see if any of these conditions will affect the rate at which the tracer will leave your body.
You’ll receive your results in a few days in the form of a percentage. This percentage is known as the left ventricle ejection fraction (LVEF).
A result between 50 percent and 75 percent is generally considered normal. This means your heart is pumping the proper amount of blood out into your body. Anything below 50 percent or above 75 percent may indicate an issue with your heart.
Possible causes of an abnormal result include:
|< 40 percent||40–55 percent||55–70 percent||> 75 percent|
|left ventricular systolic dysfunction||heart muscle damage||NORMAL||hypertrophic cardiomyopathy|
|coronary artery disease||myocardial infarction||NORMAL||hypertrophic cardiomyopathy|
|mild to severe heart failure or heart attack risk||damage from chemotherapy||NORMAL||hypertrophic cardiomyopathy|
Other possible conditions that could give you abnormal results include:
- heart valve condition
- dysfunction of your heart’s pumping mechanism
- ventricles not pumping at the same time (desynchrony)
- artery blockage
A MUGA scan costs between $400 and $1200, depending on your particular health insurance plan or the area you live in.
This scan is usually covered by your health insurance plan.
The procedures of an echocardiogram, another common imaging test for your heart, are similar to those of a MUGA scan. But how each test generates images is fundamentally different:
- A MUGA scan is a nuclear medicine test that uses gamma rays and a chemical tracer to generate images of your heart.
- An echocardiogram uses high-frequency sound waves and a transducer with a special gel to generate ultrasound images of your heart. They may be done by placing the transducer on your chest or gently down your throat on a thin, flexible tube.
Your heart function is vital to your health and quality of life, and many of the conditions that cause an abnormal MUGA scan result can have significant complications if left untreated.
If your doctor recommends this test, do it as soon as possible. The earlier the diagnosis of any of these conditions, the more likely your doctor will be able to diagnose and treat heart conditions. Every type of heart condition has a much better outcome when it’s properly taken care of before any component of your heart is damaged or becomes dysfunctional.