Measurement of acute myocardial infarcts in dogs with ⁹⁹Tc(m) stannous pyrophosphate scintigrams

Myocardial scintigrams using 99Tc(m) stannous pyrophosphate (99Tc(m) PYP) can be used to measure myocardial infarcts produced in dogs by proximal ligation of the left anterior descending coronary artery. Seven dogs had 99Tc(m) PYP myocardial scintigraphy performed 24-32 hr after ligation of the proximal left anterior artery. In each dog the scintigrams showed increased 99Tc(m) PYP uptake in the distribution of the artery. The scintigraphically visible areas of infarction, measured using interactive computer aided techniques, were compared subsequently with independent histologic measurements of myocardial infarct size. Several methods for using the area measurements to estimate infarct size were tested. The most successful method (r=0.92, p<0.01) assumed a linear relationship between the largest scintigraphic infarct area and the histologically determined infarct weight. The results suggest that 99Tc(m) PYP myocardial scintigrams provide a useful noninvasive method for measuring infarct size in dogs with proximal ligation of the left anterior descending coronary artery.