磁共振扩散张量成像定量分析猪心肌梗死早期离体心肌结构变化

Diffusion tensor magnetic resonance imaging quantitative assessment of myocardial fibres structure alteration in early stage after acute myocardial infarction of porcine in vitro

目的利用磁共振扩散张量成像(DT-MRI)研究急性心肌梗死(AMI)后离体心肌纤维束结构的改变。方法制作实验用中华小型猪AMI模型并进行离体心脏DT-MRI。纤维束示踪技术(FT)显示梗死与正常心肌纤维结构,定量分析梗死与正常心肌ADC、FA、心肌纤维束长度和数量。采用配对样本t检验及Wilcoxon检验进行统计学分析。结果FT显示正常心肌纤维走行规则,排列整齐,梗死心肌纤维结构松散,纤维长短不一。与正常心机相比,梗死心肌ADC值增加,FA值减小,心肌纤维束长度缩短,纤维数目稍减少。结论 AMI后8h即可在DT-MR图像上显示水分子扩散特性及心肌纤维结构的改变。

Objective To quantitatively assess the changes of myocardial fibres structure in early stage after acute myocardial in- farction （AMI） of porcine in vitro with diffusion tensor magnetic resonance imaging sequence （DT-MRI）. Methods AMI model of experimental porcine was established, and the DT-MRI was performed in hearts in vitro. The ADC, FA, the number and length of fibres between infarcted and normal myocardium were compared. The distribution and arrangement of myofibres in infarcted and normal hearts were observed with fiber tractography （FT）. Paired-samples t-tests or Wilcoxon tests were used for statistic analy- sis. Results FT revealed that the norrna[ myofibres were arranged in laminar, helical, well-ordered patterns, whereas infarcted myofibres were shortened, shrunken, and distorted. The ADC of the infarcted myocardium increased, and the FA decreased significantly. Myofibres in the ischemic area were shorter, and the number of fibres slightly reduced. Conclusion The water diffusion characteristics and the changes of structure of the muscle fibers can be displayed 8 h after AMI in the DT-MRI images.