增强MRI评价急性心肌梗塞后再灌注的实验研究

目的：通过动物模型的Gd－DTPA增强MRI检查并与病理对照，以评价急性心肌梗塞后再灌注的MRI表现及其诊断价值。材料和方法：复制犬的急性心肌梗塞后再灌注（12只）和非再灌注模型（8只），进行Gd－DTPA增强MRI的动态扫描，同时对犬心做不同染色的病理检查。将增强MRI扫描结果与病理检查结果进行对比，并通过MRI机内测量功能进行梗塞区心肌的信号变化特点分析。结果：由于急性心肌梗塞后再灌注和非再灌注的病理表现不一样，其增强MRI表现亦不一样。前者表现为均匀一致的强化，动态扫描也不能区分中央和周围的信号强度差别；后者则在增强早期呈不均匀的强化，其中周围区的强化要比中央区明显。动态扫描显示在增强后30分钟两区的信号强度趋于一致。结论：增强后MRI可以显示和鉴别急性心肌梗塞后梗塞心肌有无发生再灌注。

The Evaluation of Acute Myocardial Infarction with or without Reperfusion by Enhancement MRI

To evaluae the diagnostic value of enhanement MRI by correlative study of pathology and MRI manifestation in canine acute myocardial infarction with and without reperfusion. Materials and Methods: 20 dogs were divided into two groups: 8 for acute myocardial infarction without reperfusion (AMI group); 12 for acute myocardial infarction with reperfusion(reperfused group) .Both groups were studied by Gd-DTPA enhanced and dynamic MRI scan and the MRI signal characters were studied and correlated with pathologic changes. Results:Because of the differentiation changes of pathology between acute myocardial infarction with reperfusion group and without reperfusion group, the manifestations of enhancement MRI within these two gropus were different too. MRI manifestations of the infarction focus in reperfused group was homogeneously enhanced but that in AMI group was inhomogeneous. In AMI group the infarction focus in the peripheral zone was enhanced greater than that in central zone. The dynamic scan showed that the signal of peripheral zone was decreased than that of central zone. 30 minutes delay scans Showed that the singal of AMI infartion focus was homogeneous. Conclusion: Enhancement MRI can show and differentiate acute myocardial infarction with or without reperfusion.