Technetium pyrophosphate scanning in the detection of acute myocardial infarction: clinical experience.

Technetium-99m-stannous pyrophosphate (99mTc-PYP) accumulates in acutely infarcted myocardium and can be detected by scintiscanning. The clinical value of 99mTc-PYP scintiscanning was studied in 83 patients 6 hours to 21 days after the onset of acute chest pain. In 12 patients with normal electrocardiograms and serum enzyme values no uptake of 99mTc-PYP was detected on the scintigrams. Of 44 patients with electrocardiographic or enzyme evidence, or both, of acute myocardial infarction the scintigrams were positive in 31, "questionable" in 2 and negative in 11; no positive scan was obtained within 12 hours of the onset of pain, and the scans generally remained positive for up to 5 days. In 24 patients with evidence of prolonged myocardial ischemia the scans were positive in 2, questionable in 4 and negative in 18. The scans were negative in each of three patients with acute or constrictive pericarditis. Localization by electrocardiography and scintiscanning correlated nearly perfectly for transmural infarcts but subendocardial infarcts could not always be localized precisely by scintiscanning. The infarct area (total area of 99mTc-PYP uptake) correlated well with the peak serum value of creatine phosphokinase.