The MUGA scan (Multi-Gated Acquisition Scan), or Gated Equilibrium Radionuclide Ventriculography (RVG), or Gated Cardiac Blood Pool Imaging, is a nuclear medicine test of the highest level of expertise, and is designed to measure the efficiency of the ventricles of the heart.

It is an accurate and non-invasive imaging method that can give reproducible and accurate measurements of the left and right ventricular ejection fractions (LVEF and RVEF). It also provides precise information on the movement of the ventricular wall, the proportions of the chamber, and the task that the heart is performing both during systole and the diastole phases.

The MUGA scan is a well-recognized gold standard regarding the surveillance of cardiac function in patients undergoing chemotherapy with cardiotoxic medications, including anthracyclines. Moreover, it is also crucial in the treatment and diagnosis of diseases such as cardiomyopathy, ischemic heart disease, valvular diseases, and congestive heart failure.

What is a MUGA Scan?

MUGA scan is an imaging test that is used to determine the efficiency of the pumping of the heart. It is the introduction of a small dosage of some radioactive tracer, usually Technetium-99m-labeled red blood cells, into the blood.

The visualisation is correlated to the ECG (electrocardiogram) of the patient, providing a very accurate and dynamic view of the beating heart.

This makes it possible to calculate:

• Left Ventricular Ejection Fraction (LVEF).
• Right Ventricular Ejection Fraction(RVEF)
• Ventricular volumes
• Abnormalities in the movement of the wall of the region.
• Cardiac contraction phase study.

The MUGA scan offers quantitative and highly reproducible data as opposed to many of the other imaging techniques, giving it the ideal characteristic of reproducible repetitive follow-up studies.

Why is a MUGA Scan Performed?

MUGA scan is usually utilized to assess and monitor the cardiac functioning under many clinical conditions.

Key Indications:

• Chemotherapy Baseline and follow-up evaluation.
• The cardiotoxicity induced by the drugs (e.g., doxorubicin, trastuzumab, etc.) is being monitored.
• Assessment of possible or known heart failure.
• Cardiac assessment before a major operation.
• Evaluation of valvular heart disease.
• Imbibition of ventricular abnormalities or irregular wall movement.
• Inquiry of unexplained breathlessness (dyspnea) or fainting (syncope).
• Assessment of the right ventricular function in pulmonary hypertension.
• Screening before heart or bone marrow transplantation.

How is the MUGA Scan Performed?

This is done in a nuclear medicine section and may take an average of 30 to 60-90 minutes.

Steps Involved:

1. Labeling of Red Blood Cells
A small sample of blood is taken and labeled with Technetium-99m. This can be done through in vivo, in vitro, and modified methodology.

2. Radiotracer Injection
The blood cells labeled are injected into the bloodstream again.

3. ECG Gating
Small pads are attached to the chest in order to measure the heart activity and align with the picture capture.

4. Imaging
Under the gamma camera, the patient is in the comfort position, and at various angles, several pictures of the heart are taken.

5. Data Analysis
The images are advanced to software where they are used to assess ejection fraction, wall motion, and phase synchronization.

What Does the MUGA Scan Show?

This scan gives a very precise evaluation of the performance of the cardiac system, which includes:

• LVEF (Left Ventricular Ejection Fraction): It is used to measure the pumping power.
• RVEF (Right Ventricular Ejection Fraction): Measures RH function.
• Wall Motion Analysis: Wall kinesia (or absent or abnormal wall motion, hypokinesia, akinesia, dyskinesia) is detected.
• Phase Analysis: Evaluates contraction synchrony in the heart.
• Chamber Size and Shape: Measures the morphology of the ventricles.

Benefits of a MUGA Scan

• Very precise and accurate results.
• Painless and non-invasive procedure.
• Easy to use in serial monitoring, particularly in cancer treatment.
• It does not depend on body structure or the poor ultrasound windows.
• Less operator-related than echocardiography.
• Delivering quantitative (numeric) data enhances clinical decision-making.

Limitations

• Entails low level of radiation exposure.
• Poor testing of heart valves and flaws in the form.
• Does not belong to the emergency bedside evaluation.
• Special nuclear medicine equipment is required.
• A little bit more time-consuming compared to echocardiography.
• The abnormalities of ECGs can have an impact on the quality of images.

Preparation for MUGA Scan

It is easily and conveniently prepared:

• No fasting required
• Please take regular medications except where directed otherwise.
• Wear comfortable clothing
• Avoid metal accessories
• It is important to tell your physician whether you are pregnant or breastfeeding.
• Provide medical history/medical medications, particularly when receiving chemotherapy.

Conclusion

MUGA scan is a very good and accurate tool for imaging the functioning of the heart. It would be of particular importance in oncology and cardiology, where it is necessary to measure accurately and reliably the performance of the ventricles.

Although the echocardiography is frequently used as the beginning of the test, the MUGA scan is characterized by great accuracy and reproducibility, and therefore is the best test when it comes to long-term monitoring, especially in patients who are undergoing cardiotoxic treatments.

Cardiac dysfunction is detected in the initial stages of MUGA scanning to provide an increased chance of treatment and avoid severe complications.

Test Information

• Fasting: Not required

Reporting Time: Within 2 hours