Radionuclide studies in the evaluation of ischemic heart disease

In recent years, radionuclide studies have gained an important place in the evaluation of ischemic heart disease, be it as diagnostic procedures, as predictors of prognosis or for evaluation of therapy. For diagnostic purposes, myocardial perfusion studies using thallium-201 or newer technetium-99m bound perfusion agents have been used as well as radionuclide angiocardiography both at rest and during exercise/stress. Used in a Bayesian approach, these methods yield the highest diagnostic accuracy in patients with a 30% to 70% pre-test likelihood of disease, i.e. in the clinically difficult patients with atypical chest pain and/or non-specific ECG changes. In addition, scintigraphic studies have proved valuable in the setting of silent ischemia and acute myocardial infarction. These methods provide not only a yes/no answer to our diagnostic questions but allow one to assess severity, extent and localization of coronary artery disease. Portable devices are now being constructed which allow continuous ambulatory monitoring of left ventricular function by scintigraphic techniques.