Localization of myocardial disorders other than infarction with 99mTc-labeled phosphate agents.

Myocardial studies with 99mTc-labeled phosphate agents were obtained in 20 patients without demonstrable cardiovascular disease, 24 patients with unstable arteriosclerotic heart disease (ASHD) without acute infarction, and six patients with myocardiopathy. The patients without cardiovascular disease showed no localization or tracer; the patients with unstable ASHD and without acute infarction showed nonfocal ill-defined accumulation of tracer; and the patients with myocardiopathy showed diffuse accummulation of tracer throughout the confines of an enlarged cardiac outline. Careful evaluation of both the distribution and intensity of the activity, in conjunction with the clinical picture, allows differentiation among these disease processes. Since ischemic areas around infarcted tissue may show increased activity, the value of this technique for sizing acute myocardial infarction may be limited.