During the past decade, radionuclide cardiac imaging, especially radionuclide ventriculography and thallium 201 myocardial scintigraphy, has emerged as a useful technique to evaluate myocardial perfusion and cardiac performance. These methods are used in patients at rest or during exercise to diagnose and quantify coronary artery disease (CAD), to assess the extent of jeopardized (ischemic) myocardium and irreversibly damaged (scarred) myocardium, and to determine the global and regional left and right ventricular performance during systole and diastole.
Imaging techniques have also been useful in determining the presence and severity of valvular regurgitation, the detection and quantification of intracardiac shunts, and the evaluation of electrical activation sequences in disturbances of conduction and rhythm. They provide important information concerning changes in function or perfusion after medical or surgical intervention, eg, drug therapy, streptokinase therapy, coronary angioplasty, exercise training, valve replacement, and coronary arterial bypass grafting. They also provide valuable information regarding risk stratification