SPECT and PET in the evaluation of coronary artery disease.

Cardiac positron emission tomography (PET) is an accurate method for assessing myocardial perfusion and metabolism in the evaluation of coronary heart disease. PET allows more accurate detection of myocardial ischemia than single photon emission tomography (SPECT). In addition, PET has higher spatial resolution and allows attenuation correction and the quantification of various physiologic parameters. PET with 2-(fluorine-18) fluoro-2-deoxy-D-glucose is considered the standard of reference for predicting improvement in regional or global left ventricular function after revascularization by identifying hibernating viable myocardium that shows diminished perfusion and preserved metabolism. Other less commonly used clinical applications of cardiac PET include assessment of myocardial oxygen consumption and fatty acid metabolism. The use of PET in myocardial imaging is expected to increase in the near future with the regional distribution of positron-emitting radiotracers and the emergence of relatively low-cost PET systems.