Early diagnosis of myocardial infarction in the dog with 99mTc-glucoheptonate.

Early gamma imaging of acute experimental myocardial infarcts was evaluated in mongrel dogs with 99mTc-glucoheptonate. From 15 to 20 mCi were injected between 1 and 27 hr after coronary artery occlusion. Nine dogs imaged 3 hr after injection (4 hr after occlusion) showed unequivocal uptake in the region of the infarct. Fifteen dogs imaged 5-7 hr after injection (6-8 hr after occlusion) showed sufficiently well-defined regions of abnormal uptake so that planimetry could be performed reliably. Five animals imaged serially showed improvement of the image only up to about 5-7 hr after injection. Infarct-to-normal myocardium and infarct-to-blood ratios were slightly higher in dogs injected 15-27 hr after infarction than in those injected 1 hr after infarction, implying that equally good results can be obtained with injection and imaging of 99mTc-glucoheptonate at any time within the first day. No other infarct-labeling radiopharmaceutical shares this capability for the early detection a delineation of acute infarcts.