A myocardial perfusion is a noninvasive scan that is taken to show the amount of blood that is flowing through the heart muscles, as stated on WebMD. There are two sets of images, one taken during rest and the other after the heart is stressed by exercise or medication.
During the myocardial perfusion scan, the patient is given a radioactive tracer by IV, according to Johns Hopkins Medicine. This tracer travels through the bloodstream to the heart where it is absorbed by healthy heart muscle tissue. Areas that do not absorb the tracer have poor blood flow or have been badly damaged. Myocardial perfusion imaging is a good diagnostic test for patients who have suffered from a heart attack or who are experiencing chest pain due to angina, as stated by the American Heart Association.