快速评估心脏MR左心室长轴应变及其与左心室整体纵向应变的相关性

目的 探讨快速评估左心室长轴应变（LAS）的方法及其与左心室整体纵向应变（GLS）的相关性。方法 对77名健康志愿者行心脏MR检查，于收缩末期和舒张末期分别测量二尖瓣瓣环插入点连线中点与左心室心尖的心外膜边缘的距离（方法1）、二尖瓣室间隔侧插入点与左心室心尖的心外膜边缘的距离（方法2）以及二尖瓣瓣环游离壁插入点与左心室心尖的心外膜边缘的距离（方法3），计算3种方法的LAS值，并测量左心室心功能参数及GLS，比较3种LAS测值的差异，并分析其与GLS的相关性。取3种LAS值的均值，观察LAS及GLS与左心室射血分数（LVEF）的相关性。分析观察者间及观察者内测量上述参数的一致性。结果 3种方法所测LAS值差异无统计学意义（F=0.97，P=0.41）。方法1的LAS值与GLS呈显著正相关（r=0.86，P<0.001），方法2的LAS值与GLS呈中度正相关（r=0.57，P<0.001），方法3的LAS值与GLS呈较好正相关（r=0.64，P<0.001）。LAS及GLS与LVEF均呈中度负相关（r=-0.38、-0.42，P=0.04、0.02）。观察者内和观察者间一致性均好（ICC均>0.75）。结论 通过计算不同位点在心脏舒张和收缩末期相对位移的百分比可快速、简便评估LAS，且后者与GLS呈正相关。

Rapid assessment of left ventricular long axis strain with cardiac MR and correlation with left ventricular global longitudinal strain

Objective To investigate the value of rapid assessment of left ventricular long axis strain (LAS) and the correlation with left ventricular global longitudinal strain (GLS). Methods Totally 77 healthy volunteers underwent cardiac magnetic resonance (CMR). The distance between the midline of the insertion point of the mitral valve annulus and the epicardial edge of the apex of the left ventricle (LV, method 1), between the insertion point of the mitral septal space and the epicardial edge of LV apex (method 2), between the free wall insertion point of the mitral annulus and the epicardial edge of LV apex (method 3) at the end of systole and diastole was measured, respectively. LAS values of the three methods were calculated, and left ventricular function parameters and GLS were measured. The differences of LAS values were compared among three methods, and the correlation between the three LAS values and GLS were analyzed. The mean value of three LAS values was calculated, and the correlation of LAS, GLS and left ventricular ejection fraction (LVEF) was observed. The inter-observer and intra-observer consistency of above parameters were observed. Results There was no significant difference among the three LAS values (F=0.97, P=0.41). Significantly positive correlation was shown between LAS and GLS with method 1 (r=0.86, P<0.001), while moderately and well positive correlation were shown between LAS and GLS with method 2 and 3 (r=0.57, 0.64, both P<0.001), respectively. Moderately negative correlation was found among LAS, GLS and LVEF (r=-0.38, -0.42, P=0.04, 0.02). The inter-observer and intra-observer consistency of above parameters were all good (all ICC>0.75). Conclusion LAS can be assessed quickly and easily with calculating the percentage of relative displacements of different sites in the end of diastole and systole, which is correlated with GLS.