Dipyridamole is a pharmacologic stressor used in place of exercise for myocardial perfusion imaging in patients who cannot exercise due to various physical limitations. Perfusion studies with dipyridamole can identify coronary artery disease (CAD) as accurately as maximal exercise stress testing. In addition, dipyridamole myocardial perfusion studies are useful to stratify patients according to risk of subsequent cardiac events. As dipyridamole is infused, it blocks the reabsorption and metabolism of adenosine normally produced in the body, producing the desired effect on the heart, coronary hyperemia. Dipyridamole can be used with 201Tl and 99mTc myocardial perfusion tracers, for either planar or SPECT imaging, in patients who cannot exercise or who can only exercise at submaximal levels.