Introduction
A multigated acquisition scan (MUGA) is a nuclear imaging test that is highly accurate and a non-invasive procedure that will evaluate the ability of the heart to pump. In this procedure, nuclear medicine is used as a radioactive substance that is injected into the patient’s bloodstream, which will help to generate an image of the heart as it beats. This substance will get attached to the red blood cells that will move the heart's ventricles as the blood circulates, and with the help of a special camera, when viewed, it will create the image of the heart pumping.
What Is MUGA Scan?
A Multigated Acquisition (MUGA) scan is a nuclear medicine imaging test done to evaluate blood pumping by the heart. A radionuclide is an injection of a substance that is used along with a specialized camera. The radionuclide will travel through the blood, and a picture is taken of the heart by the healthcare provider. This scan will measure the contraction and relaxation of the heart muscle when at rest or exercise. MUGA scan is also known as Radionuclide Ventriculography (RNVG) and Equilibrium Radionuclide Angiocardiography (ERNA).
Why Is the MUGA Scan Done?
A MUGA scan can be done to
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Check the status of the pumping of the heart.
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Heart chamber size can be evaluated.
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The lower ventricles pumping action can be checked.
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The abnormalities in the muscle wall of the ventricles can be found.
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Certain kinds of chemotherapy drugs on the heart can be tracked to make sure it is safe to continue with chemotherapy.
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The late side effects of cancer treatment can be monitored and followed up.
Ejection fraction (EF) can be measured with the MUGA scan as EF shows how much blood the heart pumps out each time it contracts. EF is measured in terms of percentage.
How Does a MUGA Scan Work?
The radioactive substance called technetium 99m-pertechnetate (Tc-99mm) is used in small amounts in MUGA heart scans. A small amount of Tc-99 mm is injected by the healthcare provider into the veins. The chemical gets attached to the red blood cells, and these cells carry oxygen. With the help of a special camera, the provider will take pictures that show how and where the Tc-99 mm moves throughout the body as the heart beats.
How to Prepare for a MUGA Scan?
A MUGA scan is an outpatient procedure and this procedure takes about one hour, and it may extend if the exercise is included in the procedure. It is advisable not to eat 4 to 6 hours before the test, especially if it includes exercise, and avoid caffeine and tobacco for 24 hours before the scan as it may speed up the heart rate and interfere with test results. It is essential to inform the doctor regarding the medicines that are being taken and the date of the most recent chemotherapy treatment. Heart medicines such as nitrates or digoxin need to be stopped. It is necessary to inform the doctor if there is any allergy to barium.
What Happens during a MUGA Scan?
MUGA scan is done in one to three hours, and during a MUGA scan, the individual will lie on the exam table, and a special camera is positioned above the chest. Then, the technician will attach the electrodes to measure the heart activity in the chest, and a radiotracer will be injected into the vein. From several different views, pictures are taken. The individual is asked to exercise, such as walking on a treadmill, when the technician is taking pictures. Exercise will help the cardiologist to see the response of the heart to stress.
What Happens After a MUGA Scan?
After a MUGA scan, through the urine or stool, the radioactive substance will pass out of the body. For it to pass entirely out of the body, it might take a few hours to a few days. To flush it out, it is recommended to drink lots of fluids. After a MUGA scan, daily activities such as driving can be resumed. The result of this scan is that it will show how well the blood is pumped by the heart to the rest of the body, and the result is shown in percentage. The MUGA scan measures EP, and when the EF is below 50% or above 75%, there might be a heart problem. If the results are abnormal, the doctor might recommend more tests and procedures and also follow-up care.
What Are the Side Effects and Risks of MUGA Scan?
In nuclear medicine imaging, the dose of radioactive substances can vary and be different for every test, and this will depend on the body part being examined and the type of procedure. MUGA scan has minimal side effects and risks and has benefits as it outweighs the risk of exposure to the small amount of radiation received during the scan. Allergic reactions are infrequent and occur due to the radioactive substance. This scan is the safest for most individuals, and radiotracer isn’t harmful as it leaves the body after 24 hours. It is essential to inform the healthcare provider if the woman is pregnant or feeding, as this test could harm the baby.
What Is the Difference between a MUGA Scan and an Echo Test?
Both the tests create the images of the heartbeat. The echo test is an imaging test to look at the pumping of the blood by the heart, and this test uses sound waves and a transducer device with which the doctor moves it on the chest. The MUGA scan is a nuclear imaging test where a radiotracer is used, which might give a more precise ejection and fraction reading.
Conclusion
A MUGA scan is a nuclear imaging test used to evaluate the pumping of blood by the heart. The healthcare provider recommends this scan to check the heart conditions such as heart failure. This can is also used to check the signs of heart damage during cancer treatments.
