Single photon emission computed tomography (SPECT) imaging is routinely used and is the primary functional imaging tool used to evaluate the heart. More recently, positron emission tomography (PET) has been applied to the study of the heart and its uses continue to expand.
Myocardial perfusion imaging (MPI), which are created with either SPECT or PET, is used to assess the function of the heart and whether or not the heart is receiving enough oxygenated blood. The three-dimensional images of the heart produced by MPI reveal the flow of blood through the coronary arteries and the heart itself. In a perfusion stress test, images of the heart at rest are compared to the images of the heart taken immediately after exercise to determine the effect of physical stress on coronary blood flow.