A MUGA scan, also known as an equilibrium radionuclide angiogram or blood pool scan, is a diagnostic test performed to evaluate the pumping ability of the ventricles of the heart. The term gated refers to the synchronization of the imaging equipment and computer with the patient’s ECG to evaluate left ventricular function. The primary purpose of this test is to provide an ejection fraction (the amount of blood ejected from the ventricle during the cardiac cycle).
Once the patient is injected with a small amount of radioactive tracer, the distribution of radiolabeled red blood cells (RBCs) is imaged by synchronization of the recording of cardiac images with the ECG. This technique provides a means of obtaining information about cardiac output, end-systolic volume, end-diastolic volume, ejection fraction, ejection velocity, and regional wall motion of the ventricles. Computer-aided imaging of wall motion of the ventricles can be portrayed in the cinematic mode to visualize contraction and relaxation. This procedure may also be performed as a stress test. A MUGA scan is not often performed on children.
This procedure may be performed with or without stress. A MUGA scan with the patient at rest could be performed at the bedside if necessary, if the nuclear medicine department has a mobile gamma camera.
Draw a blood sample from the patient and combine it with 99mTc-PYP (to label the patient’s RBCs). Then, inject the blood slowly back into the patient through an IV line. For children younger than 3 years, sedation may be required for the injection and to allow the pediatric patient to hold still for the required 20–30 minutes. Alternatively, perform a cardiac flow study.
Attach the patient to an ECG machine. The patient’s R wave signals the computer and camera to take several image frames of the heart for each cardiac cycle.
Image the patient immediately after injection of the labeled RBCs.
See Chapter 1 guidelines for safe, effective, informed intratest care.
Abnormal MUGA procedures are associated with:
Heart failure
Change in ventricular function due to infarction
Persistent arrhythmias from poor ventricular function
Regurgitation due to valvular disease
Ventricular aneurysm formation
Pretest Patient Care
Explain the purpose, procedure, benefits, and risks.
Follow standard NMI pretest precautions.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Care
Review test results; report and record findings. Modify the nursing care plan as needed. Review MUGA scan outcomes and monitor appropriately for cardiac disease.
Refer to standard nuclear scan posttest precautions.
Follow guidelines in Chapter 1 for safe, effective, informed posttest care.