A New Method for Radionuclide Imaging of Acute Myocardial Infarction in Humans

Abstract

A new method of visualizing acute myocardial infarction in humans following intravenous injection of 15 mCi-5 mg of 99m Tc stannous pyrophosphate in 23 patients is reported. Fifteen patients had histories suggestive of acute myocardial infarction and subsequently developed electrocardiogram and enzyme changes that confirmed the clinical diagnosis. Eleven of the 15 patients were scanned 3-5 days postinfarction, and all had positive scintigrams. The four remaining patients were scanned 7-10 days after their myocardial infarction; two had positive scintigrams. In those 8 patients with chest pain but without ECG and enzyme changes suggestive of myocardial infarction, scintigrams were negative. Positive scintigrams in the patients with myocardial infarction are thought to be due to incorporation of pyrophosphate into the crystalline structure of the hydroxyapatite found within the mitochondria of irreversibly damaged myocardial cells. The location of the acute myocardial infarction by scintigram correlated well with ECG localization in the 13 patients with positive scintigrams. This imaging method shows promise in 1) identifying the presence of acute myocardial infarction in patients with chest pain, 2) determining the location of acute myocardial infarction with a high degree of accuracy, 3) detecting the extension of the infarction, and 4) the possibility of determining the size of acute myocardial infarctions.