Nuclear cardiology studies use noninvasive techniques to assess myocardial blood flow, evaluate the pumping function of the heart as well as visualize the size and location of a heart attack. Among the techniques of nuclear cardiology, myocardial perfusion imaging is the most widely used.
Myocardial perfusion images are combined with exercise to assess the blood flow to the heart muscle. Exercise can be in the form of walking on the treadmill or riding a stationary bicycle. A “chemical” stress test using the drug dipyridamole, adenosine, regadenoson, or dobutamine can be performed in patients who are not able to exercise maximally, providing similar information about the heart’s blood flow.
A small amount of an imaging agent is injected into the blood stream during rest and during exercise or chemical stress. A scanning device (gamma camera) is used to measure the uptake by the heart of the imaging material during (exercise or chemical stress) and at rest. If there is significant blockage of a coronary artery, the heart muscle may not get enough of a blood supply in the setting of exercise or during chemical stress. This decrease in blood flow will be detected by the images.