Localization of 99mTc-labeled pyrophosphate and calcium in mycoardial infarcts after temporary coronary occlusion in dogs.

SummaryThe location and magnitude of 99mTc concentration was assessed following 15 or 40 min of temporary coronary occlusion to evaluate uptake with respect to irreversible vs reversible ischemic cell injury and with respect to the presence or absence of increased myocardial Ca2+ content. 99mTc did not accumulate in any samples after 15 min of ischemia (reversible injury). 99mTc uptake was observed in 6 of 10 dogs following 40 min of occlusion and the high 99mTc ratios were associated with massive tissue calcification. The results indicate that 99mTc accumulation is specific for irreversible ischemic injury and is associated with tissue calcification.