A Multiple Gated Acquisition (MUGA) scan is a type of medical diagnostic imaging which is used to assess heart function. The MUGA scan is also referred to as a nuclear ventriculogram. There are a number of reasons for such a scan to be ordered, ranging from routine check-ups on heart function during chemotherapy treatments to a through examination of a patient who has recently experienced a serious cardiac event. When done properly, a MUGA scan should be painless for the patient, and it is generally not harmful, except to pregnant women or other people who may be especially susceptible to radioactive substances.
When a MUGA scan is performed, a small amount of a radioactive isotope is attached to red blood cells and then injected into the blood stream. The isotope emits weak gamma rays which can be detected with a special camera positioned over the patient. As the blood fills the ventricles or chambers of the heart, the camera picks up a clear picture of the heart's function, creating an animated image of the beating heart which is used in diagnostics.
There are some variations on the basic MUGA scan. A patient may be asked to exercise during the scan, for example, to get an idea of how the heart performs under stress. Some scans may also involve the use of a vasodilator like nitroglycerin to see how this changes heart function. After around 48 hours, most patients will have successfully flushed the radioactive isotope used in the scan from their bodies.
When a MUGA scan is interpreted, doctors can look at things like the ejection fraction, or the amount of blood pumped out of a ventricle every time the heart beats. The performance of the left ventricle is often closely analyzed on a MUGA scan, because left ventricle health is very important to overall physical health. Other heart function parameters are also included in an interpretation of a MUGA scan.
This noninvasive test is extremely accurate. MUGA scans can often detect small changes in heart function early on, allowing doctors to address them before they become serious problems. MUGA scans can also allow doctors to clearly see specific areas of damage in the heart, and they are used to assure doctors that their treatment plans are working. This is especially important in medical disciplines like oncology, as heart function can be impacted by cancer treatment, and it is important to ensure that the patient stays as healthy as possible, or the chemotherapy drugs may have to be adjusted.