MRI of Reperfused Myocardial Infarct in Dogs

The current study evaluated the capability of magnetic resonance imaging (MRI) to detect acutely injured myocardium in the first 5 hr after a 1-hr period of occlusion followed by reperfusion of the coronary artery and to determine if magnetic relaxation times could be used to differentiate injured from normal myocardium. Fourteen dogs underwent left anterior descending coronary arterial occlusion for 1 hr, followed by reperfusion. Electrocardiographic gated MRI was performed before and during coronary artery occlusion and immediately after reperfusion, and serially up to 5 hr postreperfusion. In all dogs with postmortem evidence of myocardial infarction (n = 7), regional increase of signal intensity was observed in the anterior wall of the left ventricle as early as 30 min after reestablishing blood flow to the jeopardized myocardium. The area of increased signal intensity in the myocardium conformed to the site of myocardial infarction found at autopsy. The signal intensities of the jeopardized myocardiu...