Clinicopathologic Findings in 52 Patients Studied by Technetium-99m Stannous Pyrophosphate

SUMMARY Scintigraphic, clinical and pathological findings were correlated in 52 patients studied by tech-netium-99m stannous pyrophosphate ("mTc-PYP) myocardial scintigraphy before death or surgical resection of myocardium. Fifty-nine clinical events were studied with scintigraphy in the 52 patients; 41 of the 59 were associated with one or more abnormal "mTc-PYP studies and 18 with normal 9OmTc-PYP scintigrams. Myo-cardial scintigrams were positive in 29 of 31 cases with clinicopathological evidence of a corresponding dis-crete, grossly obvious acute myocardial infarct, including 16 of 16 transmural myocardial infarcts and 13 of 15 subendocardial infarcts. In 16 of 18 cases, negative myocardial scintigrams correlated with the absence of acute myocardial infarction determined by clinicopathological evidence. In two cases small subendocardial in-farcts (< 3 g) were not detected by "mTc-PYP myocardial scintigraphy. Of the 12 additional instances of positive 9OmTc-PYP myocardial scintigrams, five were associated with clinical unstable angina pectoris and seven were in the category of persistently positive scintigrams, since the scans were obtained 2.5 months or longer after proven or suspected acute myocardial infarcts. In all 12 instances, the positive BOmTc-PYP scinti-grams were associated with evidence of multifocal irreversible myocardial damage consisting of myocytolysis, coagulation necrosis and/or fibrosis, and the histological age of the lesions was compatible with acute injury corresponding to the time of scintigraphy. The findings indicate that a positive "mTc-PYP myocardial scinti