What is a MUGA scan?
Multigated acquisition scan (MUGA) creates video images of the lower chambers of the heart to check if they are pumping blood properly. It demonstrates any abnormalities in the size of the chambers (called “ventricles”) and in the movement of blood through the heart. Other names for this test include cardiac blood pool imaging, cardiac nuclear scan, nuclear ventriculography, and radionuclide ventriculography.
An echocardiogram is generally recommended instead of a MUGA scan for people who will be receiving treatments for cancer that can damage the heart. An echocardiogram is also used more often to find a pre-existing heart condition. But some individuals may need a MUGA scan instead. Sometimes doctors also use MUGA scans as follow-up care to find possible long-term cardiac side effects or late effects. Late effects can occur more than 5 years after treatment. Cancer survivors who may need follow-up MUGA exams include:
- People who have received radiation therapy to the chest
- People who have had a bone marrow/stem cell transplant or sure types of chemotherapy
Preparation before MUGA Scan
When your agenda is MUGA scan, you will obtain detailed instructions on how to prepare.
What to eat. You may not be able to eat or drink for 4 to 6 hours before the test. You may also be asked to escape caffeine and tobacco for up to 24 hours before the test.
Topics to discuss. Be prepared to discuss the following topics with your healthcare team:
- All medications you are taking, especially heart medications such as digoxin (various brands) and nitrates, can affect test results
- Any drug allergies you have, even if you are allergic to barium
- Whether you would take your usual medications on the day of the procedure
- Any medical condition you have, including a fast and irregular heartbeat; obesity; and not being able to lie down or still
- If there is any chance that you are pregnant or if you are breastfeeding. The small amount of radiation used in the test can harm the developing baby or pass through breast milk.
- If you have had recent nuclear tests, such as bone or thyroid scans
- Any concerns you may have about the test
MUGA scan risks
There are not many risks associated with a MUGA scan. The level of radioactivity produced by the marker material and the camera is extremely low and is not known to cause any short or long-term damage to your body. In fact, a MUGA scan produces less radioactivity than a typical X-ray scan.
It is possible to have an allergic reaction to radioactive tracer material. Symptoms can vary depending on the type of marker material used and can include:
- Feeling sick
- Throwing up
- Have diarrhea
- Have an irregular heartbeat
- Develop a rash or redness on the skin
- Experiencing visible swelling due to fluid build-up (edema)
- Feeling tired or disoriented
You may also have trouble clearing the marker fluid if you have a kidney, liver, or heart condition that requires you to limit your fluid intake. Talk to your doctor before the test to see if any of these conditions will affect the rate at which the marker will leave your body.
What happens during the test?
A technician will place electrodes (small round sticky patches) on the skin on your chest. Men can shave their chest hair to allow for a better connection. The electrodes are connected to an electrocardiograph (EKG) monitor that records the electrical activity of your heart during the test.
An intravenous (IV) line will be implanted into a vein in your arm.
The operator will ask you to lie on the exam table under the gamma camera. A nuclear imaging technician will draw a small amount of blood, syndicate it with a radioactive tracer, and inject the mixture into your IV. The radioactive tracer marks the red blood cells so the camera can detect them. The marker stays in your bloodstream for several hours and does not enter the cells of your tissues.
The camera on the table focuses on the heart and analyzes the number of radioactively labeled red blood cells that are pumped out of the heart with each beat. Several pictures can be taken to look at the different walls of your heart.
This test calculates your ejection fraction, a measure of how well your heart pumps with each beat. A normal ejection fraction ranges from 50 to 70 percent. An ejection portion of 65 percent, for example, means that 65 percent of the total quantity of blood in the left ventricle is pumped out with each beat of the heart. The ejection fraction may be lower when the heart muscle has been damaged due to a heart attack, disease of the heart muscle (cardiomyopathy), or other causes.
How long will the test last?
The MUGA scan takes between one and two hours to complete.
How to perform a MUGA scan?
A MUGA scan is usually performed as an outpatient procedure in a hospital’s nuclear medicine department. This means that it will not stay overnight. The test takes about 1 hour, but it may take longer if the test contains exercise.
Before having any nuclear medicine test, it is important that you tell the nuclear medicine staff if you are breastfeeding or pregnant or think you may be.
Tell the staff if you have recently had any other nuclear medicine tests, such as a bone or thyroid scan.
You may be told that:
- Do not eat or drink for 4 to 6 hours before the test, especially if the test includes exercise.
- Avoid caffeine and tobacco for 24 hours beforehand the scan.
- Bring a list of the medications you are taking and the date of your most recent chemotherapy treatment.
You may be told not to wear clothing with metal zippers, belts, or buttons on the day of the scan. Or you can put on a gown for the test. If you wear glasses, jewelry, or objects that may interfere with the test, you will be asked to remove them.
Your doctor will ask about your history of heart disease and what tests or procedures have been done on your heart.
The technician will take a blood sample to mix with the radioactive substance. The mixture is then injected back into the vein.
You will have small pads or electrodes attached to the skin of your chest. These monitor your heart rate and match the images to your heartbeat.
A gamma camera detects the radiation emitted by radioactive material in the cells and tissues of the heart. It takes pictures of the radiation and sends them to a computer. It is important to remain still while the camera takes pictures. You may need to change your position so that the camera can take pictures from different angles. Between the images, you may be asked to walk on a treadmill or use an exercise bike to see how your heart responds to the stress of exercise (MUGA stress).
Side effects of MUGA scan
The dose of X-rays or radioactive materials used in nuclear medicine imaging may be different for each test. The dose depends on the type of procedure and the part of the body being examined. In general, the dose of radioactive material administered is small and you are exposed to low levels of radiation during the test. The benefits of performing a MUGA scan outweigh the risk of exposure to the small amount of radiation received during the scan.
Allergic reactions to radioactive material can occur but are extremely rare.
Before the test
A MUGA scan typically takes between one and two hours to complete. When planning your day, allow enough time to travel to the testing facility. In addition, you may also need to complete the paperwork and/or wait to be taken to the room where the exam will take place. Ask your doctor how long, realistically, you will need to reserve for your MUGA scan.
The MUGA scan is an outpatient test. It is regularly done in a hospital or clinic.
What to wear
When you get dressed for your appointment, consider the type of test you will have. If you will be running on a treadmill or riding a stationary bike during your MUGA scan, wear the same type of clothing that you would wear for exercise, including appropriate shoes.
If exercise will not be part of your test, wear loose-fitting clothing and comfortable shoes.7 This will make it easier to put on a hospital gown if asked.
Food and drink
If you will have a resting scan, you will likely be instructed to avoid alcohol or caffeine (not only in coffee or tea but also in soda) several hours before the test.
If you will exercise during the test, you will be instructed not to eat or drink anything except water for four hours beforehand.
You may be able to complete any necessary paperwork at home before undergoing a MUGA scan; if so, bring that paperwork to your appointment. Also, please bring your health insurance card, driver’s license, or another form of official identification and an acceptable form of payment in case you owe a copayment at the time of the test.
If you do not have health insurance and must pay out of pocket, you will also need to bring payment. The cost of the test will depend on where you live, but by some estimates, the national average for the test is around $ 1,200.
During the test
Knowing how to prepare for a MUGA scan and what to expect during and after will ease any anxiety you may have about the test.
Before a MUGA scan at rest, you may be asked to change into a hospital gown. If you will be exercising during the test and did not wear proper clothing or shoes, you will need to change into those.
Either way, once you are properly dressed, a technician will place electrodes (small round sticky patches) on your chest. If you have chest hair, you may need to shave where the electrodes will be placed.
The electrodes are connected to an electrocardiograph (EKG) monitor that records the electrical activity of the heart during the test.
Subsequently, a small quantity of technetium 99 (a radioactive substance) will be injected into a vein in your arm. Technetium 99 will adhere to red blood cells and therefore circulate through the bloodstream.
After the test
After the test, you can change into your street clothes, go outside, and resume your normal activities right away.
How do I understand the results?
You will receive your results in a few days as a percentage. This percentage is known as the left ventricular ejection fraction (LVEF).
A result between 50 and 75 percent is generally considered normal. This means that your heart is pumping the right amount of blood to your body. Anything below 50 percent or above 75 percent can indicate a problem with your heart.