99mTc-aminohexylidendiphosphonate and 99mTc-pyrophosphate in the scintigraphic diagnosis of experimental cardiomyopathy in dogs.

Experimental cardiomyopathy was provoked in 24 dogs with high intravenous doses of adrenaline and theophylline. These lesions were studied by means of the new agent 99mTc-AHDP and 99mTc-PYP in comparison. Cardiomyopathy could be imaged as early as 4 h after the onset of involvement but not later than 7 days. A maximum accumulation occurred in lesions 24 h old. 99mTc uptake in the myocardium was graded scintigraphically. 99mTc-AHDP was accumulated in the altered myocardium to a greater extent than 99mTc-PYP. Scintigraphic findings were in good agreement with plasma levels of creatine-kinase. A comparison with histology demonstrated that the maximum accumulation of radiopharmaceuticals occurred at the time when the development of myocardium involvement reached the stage of myocytolysis.