SPECT and PET in the evaluation of coronary artery disease

Cardiac positron emission tomography (PET) is an accurate method for assess ing myocardial perfusion and metabolism in the evaluation of coronary heart disease. PET allows more accurate detection of myocardial ischemia than si ngle photon emission tomography (SPECT). In addition, PET has higher spatia l resolution and allows attenuation correction and the quantification of va rious physiologic parameters. PET with 2-(fluorine-18) fluoro-2-deoxy-D-glu cose is considered the standard of reference for predicting improvement in regional or global left ventricular function after revascularization by ide ntifying hibernating viable myocardium that shows diminished perfusion and preserved metabolism. Other less commonly used clinical applications of car diac PET include assessment of myocardial oxygen consumption and fatty acid metabolism. The use of PET in myocardial imaging is expected to increase i n the near future with the regional distribution of positron-emitting radio tracers and the emergence of relatively low-cost PET systems.