MR imaging of acute myocardial infarction

This paper reports on superparamagnetic iron oxide particles (AMI-25) evaluated in comparison with paramagnetic Gd-DOTA for the MR evaluation of acute myocardial infarct size. Twelve openchest dogs underwent 2 hours of LAD occlusion followed by 6 hours of reperfusion. AMI-25 and Gd-DOTA were intravenously injected 1 hour and 10 minutes before euthanasia, respectively, in two groups of six dogs. Gradient-echo and T1- and T2-weighted spin-echo images were obtained in six AMI-25-injected excised hearts, and T1- and T2-weighted images in six Gd-DOTA injected excised hearts. Infarct size was evaluated by planimetry of each 8-mm-thick transverse slice after ex vivo double staining and correlated with the planimetry of each 8-mm-thick transverse MR section