Microcirculation of intramyocardial hemorrhage caused by reperfused myocardial infarctions with ultrasmall superparamagnetic iron oxide cardiac magnetic resonance imaging

BACKGROUND: The actual role of the coronary microcirculation, which is massively injured by myocardial infarction (MI), in intramyocardial hemorrhage (IMH) pathophysiology is still not fully understood. PURPOSE: To determine the change and distribution of microcirculation of myocardial edema (ME), IMH, MI, and the remote area of early reperfusion using 7.0-T cardiovascular magnetic resonance (CMR) in a rat model of acute MI. MATERIAL AND METHODS: Eight rats with 60-min myocardial ischemia followed by reperfusion were investigated. On days 2 and 7, after the acquisition of T2*-mapping and T2-mapping images, late gadolinium enhancement imaging was performed to evaluate the extent of myocardial ischemia after an injection of Gd-DTPA. On days 3 and 8, after the injection of ultrasmall superparamagnetic iron oxide (USPIO), T2*- and T2-mapping images were acquired. The R2 values of ME, IMH, MI, and remote areas were measured. RESULTS: > 0.05). CONCLUSION: Microvascular injury of IMH and MI is the most severe among all the studied myocardial injuries in the early reperfusion of MI, while microvascular density decreased during follow-up.