Myocardial perfusion imaging in coronary artery disease

Radionuclide myocardial perfusion imaging (MPI) can be used to demonstrate the presence of coronary heart disease and to risk stratify and guide management of patients with known disease. It has the ability to localize hemodynamically important coronary stenoses, and assess the extent and severity of coronary obstruction by the presence and extent of perfusion defects. A normal stress MPI indicates the absence of coronary obstruction and hence of clinically significant disease. Cardiac PET has the advantage from SPECT of higher spatial and temporal resolution, and a decreased radiation exposure to patients. Hybrid cardiac imaging combining SPECT or PET with CT data appears to offer superior diagnostic and prognostic information in patients with intermediate risk for CAD. A significant progress in better quantification of myocardial blood flow and coronary flow reserve has recently been seen. Also several studies have demonstrated that the combination of imaging apoptosis and matrix metalloproteinases production can help imaging vulnerable plaque and identifying the group of high-risk asymptomatic patients who will benefit most by an imaging procedure.