首过灌注及心肌活力分析在猪心肌梗死存活心肌诊断的实验研究

First pass perfusion and viability MR imaging in myocardial infarction model of pigs: experimental study

目的评估心肌灌注成像、心肌活力及运动分析MRI在猪心肌梗死存活心肌诊断中的应用价值。方法猪心肌梗死3天模型14例、3周模型12例进行心脏MR检查。BFFE用于观察心肌运动,快速梯度回波序列(T1-TFE)用于观察首过心肌灌注表现;反转恢复梯度回波序列用于观察延迟时相心肌活力表现。结果猪梗死心肌内的首过灌注诊断敏感性为92%。心肌活力分析示左心室心肌内存在不同范围的强化灶或心肌变薄,诊断敏感性为75%。心肌运动减弱节段与强化节段基本一致,诊断敏感性为92%。明显纤维化或瘢痕心肌表现为心肌变薄并始终保持低信号。结论通过综合分析延迟强化,运动能力显著降低和可能存在的首过灌注缺损,可以更有效地识别梗死或瘢痕心肌。

Objective To evaluate the role of myocardial perfusion, viability and cine-MR imaging on pig myocardial infarction models. Methods Fourteen pigs with myocardial infarction （3 days）, 12 pigs with myocardial infarction （3 weeeks） underwent MR scanning. Cine-MR imaging acquaired by BFFE sequence were used to analyze the motion of heart. T1-TFE sequence was used to detect the first pass perfusion after injection of 0.1 mmol/kg Gd-DTPA. Inversion recovery viability sequence was used to recognize the high signal in the infarct myocardia. Results The diagnostic sensitivity of the first pass perfusion weighted images was 92%. The findings of enhancement region or attenuation in the infarct myocardia of 3-day pigs, 3-week pigs were detected in the delayed viability sequence images. The diagnostic sensitivity of that was 75%. The myocardial wall of hyper enhancement had a weaken motion in cine-MR images, and the diagnostic sensitivity was 92%. The symptom of attenuation and keeping lower signal of myocardial wall in viability images was detected in the obvious fibrosis myocardia or scar. Conclusion The combination of all imaging findings in the first pass perfusion, viability imaging and cine-MR imaging can view the true infarction and scar of heart.