应用药物负荷心脏MRI探讨冠心病心肌收缩功能与心肌灌注的关系

目的本研究主要探讨心脏MRI(CMRI)结合药物(小剂量ATP)负荷试验中,心肌收缩功能与心肌灌注之间、心肌收缩功能储备与心肌灌注储备之间的关系。方法我们采用1.5T磁共振扫描仪对68例冠心病患者进行了心脏电影MR成像,其中19例患者冠状动脉造影证实有阳性结果(血管狭窄>50%)。真正快速稳态梯度回波(FIESTA)序列用于观察静息状态下和小剂量ATP负荷状态下的心肌运动;平面回波成像(EPI)序列用于ATP负荷前后的MR心肌灌注成像。各序列均采用左室短轴位成像。电影MRI图像采用MASS软件包对左室各节段室壁运动进行半定量计分,同时对灌注曲线进行定量分析。最后对各节段心肌灌注参数和室壁运动评分进行统计分析。结果在静息状态和负荷状态下,心肌灌注参数均随着室壁运动评分的增加而降低。在小剂量ATP负荷状态下室壁运动较负荷前改善的心肌节段较无改善者的心肌灌注储备值低。结论心肌灌注和心肌收缩功能具有很好的相关性,对两者的综合判断有助于提高CMRI评估心肌活性的价值。

Relationship between myocardial contractile function and myocardial perfusion by using pharmacological stress cardiac MR imaging

Objective To investigate the relationship between myocardial contractile function and myocardial perfusion,as well as the relationship between their reserves.Methods Six-eight patients with coronary artery diseases underwent MR imaging(1.5T).Short-axis images acquired by cine fast imaging employing steady-state acquisition(FIESTA)sequence were used to analyze the motion of the different anatomy regions;echo-planar imaging(EPI)sequence were used to detect the characteristics of magnetic resonance myocardial perfusion imaging(MRMPI)before and after ATP stress myocardial perfusion and regional wall motion was assessed in a 8-segment model.Segmental myocardial perfusion parameters were derived from signal intensity versus time curves,and wall motion abnormalities were graded.The relationship between myocardial contractile function and myocardial perfusion was also analyzed.Results Myocardial perfusion parameters were lower in segments with higher scored wall motion relatively and myocardial perfusion reserve was significantly higher in segments with ameliorated wall motion when under ATP stress than those without.Conclusion There is high relativity between myocardial contractile function and myocardial perfusion.Evaluating both of them can improve the validity of MRI in the identification of myocardial viability.