[Diagnosis of acute myocardial infarct using 2 new tracers: 111indium-labeled antimyosin antibodies and 99m-technetium isonitriles].

The clinical usefulness of scintigraphies with 111Indium radiolabeled antimyosin antibodies (Myoscint) and 99mTc isonitriles (Cardiolite) for the detection and topographic location of acute myocardial infarction (AMI) has been evaluated in 29 patients admitted for suspected AMI. The scintigraphic results were compared to ECG and enzymatic data and, in 22 patients, to coronaro-angiography. The CK enzymes (from 258 to 4986 IU/l, mean 1429) were elevated in all, while the ECG showed diagnostic Q waves in only 21 patients. 2 patients died in cardiogenic shock, one after massive extension of AMI. Myoscint and Cardiolite images were positive in all 29 patients. Both techniques showed concordant results in 27/28 comparable patients, and localized the AMI in 8 patients without diagnostic ECG. Regional comparison in 140 segments of 28 patients was concordant in 91% of the segments, totally discordant in 3 segments and partially discordant in 9 segments. In conclusion, this preliminary study in selected patients shows the clinical usefulness of 111In radiolabeled antimyosin antibodies and 99mTc isonitriles for detection of AMI in all 29 patients and for topographic localization in more than 90% of the cases. Imaging with 111In radiolabeled antimyosin antibodies seems particularly useful in patients with non diagnostic ECG and previous MI and for the detection of right ventricular infarct extension.