^99mTc-Aminohexylidendiphosphonate and ^99mTc-Pyrophos phate 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.

Zusammenfassung

Bei 24 Hunden wurde eine experimentelle Kardiomyopathie mit hohen i.v. Dosen von Adrenalin und Theophyllin hervorgerufen. Diese Läsionen wurden mit dem neuen Radiopharmakon ^99mTc-AHDP und ^99mTc-PYP im Vergleich untersucht. Die Kardiomyopathie konnte bereits 4 h nach Beginn, aber nicht später als nach 7 Tagen dargestellt werden. Die höchste Anreicherung wurde in 24 h alten Läsionen festgestellt. Die ^99mTc-Anreicherung im Myokard wurde szintigraphisch eingestuft. ^99mTc-AHDP wird in größerem Maße im veränderten Myokard angereichert als ^99mTc-PYP. Die szintigraphischen Befunde stimmen sehr gut mit den Plasmaspiegeln der Kreatinkinase überein. Ein Vergleich mit der Histologie zeigte, daß die höchste Anreicherung des Radiopharmakons zu dem Zeitpunkterscheint, wenn die Entwicklung der myokardialen Beteiligung das Stadium der Myozytolyse erreicht hat.

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