The MUGA scan is especially useful for
assessing the size and pumping strength
of the ventricles. In people with heart
failure, for example, the scan images often show enlarged
and weakened ventricles.
MUGA Scan Images
The two upper panels show scan images
of the left ventricle: (a) just before it pumps blood,
and (b) just after it is done pumping blood (but before
it begins to fill with blood again).
The two lower panels show diagrams
that represent: (c) the ejection fraction, and (d) the
wall motion of the left ventricle.
The ejection fraction is
a commonly used term which measures the pumping strength
of the heart. The ejection fraction is the proportion
of blood that is pumped from the left ventricle (the
main pumping chamber) with each heartbeat. A normal
ejection fraction is greater than 50 percent. Patients
with heart failure often have an ejection fraction
of less than 40 percent.
The MUGA scan also provides information
about heart wall motion. In
people who have had a heart attack, for example, the
scan images often show poor wall movement in the area
of the heart muscle that was damaged and scarred.
