特征追踪心脏磁共振技术测量汉族健康人群左心室心肌应变正常参考值的研究

目的 采用特征追踪心脏磁共振技术（feature tracking cardiac magnetic resonance, FT-CMR）对中国汉族健康人群的左心室心肌应变的正常参考值进行研究。方法 纳入经体检及心脏超声证实的汉族健康志愿者60例，采用3.0T磁共振成像系统（3.0T，Magnetum，Tim Trio， Siemens ，Erlangen， Germany）稳态平衡自由进动序列完成心脏功能成像，采用FT-CMR(Trufisp strain analysis, Siemens) 软件对60例健康志愿者进行左心室径向、周向、纵向应变及应变率分析。结果 所有患者图像质量符合分析要求。分析得到左心室应变及应变率参考值。左心室整体应变值均具有良好的重复性。其中，左心室短轴整体径向收缩期峰值应变为（37.7±9.6）%；整体周向收缩期峰值应变为（-18.4±3.3）%；长轴整体纵向收缩期峰值应变为（-15.2±2.3）%。左心室整体径向应变随年龄增大而增大（ r=0.416， P<0.001），而整体周向应变（ r=-0.273, P=0.035)、整体舒张期周向应变率（ r=-0.436， P<0.001)及舒张期纵向应变率（ r=-0.326， P=0.011)随年龄增大而减小。整体周向、纵向应变，舒张期纵向应变率女性大于男性，而收缩期周向应变率女性相对男性较小。左室应变参数同左室的收缩末容积指数及左心室射血分数存在相关性。结论 FT-CMR是一种简便、可重复性好的分析左心室心肌应变的方法。本研究结果提供了健康中国汉族人群左室心肌应变的参考值范围，并且揭示了性别及年龄对心肌应变的影响。

Preparing Bifidobacteria for Quantitative Detections

Objective To establish reference values for left ventricular (LV) myocardial strains in a cohort of healthy Chinese volunteers with feature tracking cardiac magnetic resonance imaging. Methods A total of 60 healthy volunteers were recruited, receiving a cardiac magnetic resonance imaging (CMR) examination at 3.0T scanner (Tim Trio, Magnetum, Siemens, Germany). A new feature tracking CMR software (Trufisp-strain, Siemens) was used to analyze left ventricular myocardial strain parameters, including radial, circumferential, longitudinal strain, systolic strain rate, and early diastolic strain rate. Results The image quality was sufficient to perform strain analysis.The reference values of global strain, global strain rate and segmental strains were obtained. A good inter- and intra-observer agreement was achieved in global strain analysis (except circumferential straininter-observer in apical level),with (37.7±9.6)% for LV global mean radial strain, (-18.4±3.3)% for circumferential strain and (-15.2±2.3%) for longitudinal strain, respectively.Age was positively correlated with global mean radial strain ( r=0.416, P<0.001) and negatively correlated with early diastolic strain rate (circumferential or longitudinal) and circumferential strain( r=-0.436, P<0.001; r=-0.326, P=0.011; r=-0.273, P=0.035, respectively). Women showed higher circumferential and longituinal strain values and lower CM(155.3mm]systolic circumferential strain rate than men. The strain parameters were correlated with left ventricular ejection CM)]