Myocardial perfusion imaging procedures are diagnostic studies that are performed in conjunction with a stress test to evaluate whether the heart muscle (the myocardium) is getting adequate blood supply. These procedures are generally used to assess the likelihood of coronary artery disease. In the presence of coronary artery disease, blood supply to the heart muscle is impaired.
The most common two radioisotope tracers used to produce images of the blood supply to the heart muscle are thallium and sestamibi. Both of these isotopes are injected intravenously during the stress test. Images of the heart are acquired soon after the exercise portion of the stress test. A special camera is used to take numerous pictures of the heart after the stress test. In addition, another set of images of the heart are acquired while the patient is at rest. The stress and rest cardiac images are compared side by side to look for both fixed and reversible defects in blood supply to the heart muscle. By these images, we can tell whether or not portions of the heart muscle are scarred and whether or not there is a likelihood of coronary artery disease. The results of the stress test, the myocardial perfusion images, and the individual patient's clinical course are then correlated by the patient's physician to determine if further cardiac testing is necessary. Three of the twelve cardiologists in our group are able to interpret the results of the myocardial perfusion imaging procedures.