The existence, severity, and degree of myocardial ischemia or infarction are assessed by single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). The heart's blood supply is assessed using a myocardial perfusion SPECT (Single Photon Emission Computed Tomography) examination, often known as a cardiac stress-rest test. Two sets of blood flow images are obtained: the first after a time of rest, and the second after a stressful period that includes treadmill activity.