Distribution of sup(99m)Tc-labelled pyrophosphate in the myocardial necrosis site in dogs

The distribution was studied of sup(99m)Tc-pyrophosphate in the necrotic site of the myocardial infarction experimentally induced in dogs to clarify the principle of the incorporation of the pyrophosphate in the site of necrosis and of its distribution. The maximum pyrophosphate incorporation was found to be along the periphery of the lesion while in the middle the concentration of the substance was lower. In small lesions the maximum pyrophosphate concentration was observed in the middle of necrosis. The incorporation of pyrophosphate was found to be dependent on the collateral blood circulation. It very well correlated with the amount of calcium in the tissue which, in turn, again varied with the collateral circulation. The collateral circulation was observed using sup(113m)In-labelled albumin macroaggregate. (L.O.)