Could you tell me what is the purpose of a myocardial perfusion scan [nuclear test]?

Perfusion scans: The main risks to these studies relate to the exercise stress used and to the radiation exposure. In general both are very well controlled and the complications and negative outcomes to these studies are very few and uncommon in good labs. The commonest side effects are with Persantine and Adenosine used to simulate exercise. Regadenoson a newer agent has few side effects.

CAD: The purpose is to diagnose significant coronary artery disease (CAD). If the scan is positive for ischemic changes in the heart, then you will benefit from aggressive medical treatment, angiographic treatment, or surgery. If the scan is negative (and done properly), your risk for CAD or a significant injury such as a heart attack in the next few years is very low.

See blood flow: Myocardial perfusion studies show the pattern of blood flow (perfusion) to the tissue of the heart muscle. The radiotracer goes where the blood goes and this shows how well the tissue is nourished. It can be an indicator of blocked arteries when the perfusion pattern is abnormal.