四种超声心动图技术评价正常人心肌生物力学参数及其与心功能相关关系

Study of normal myocardial biomechanical parameters and their relationship with cardiac functions using multimodality echocardiographic techniques

目的:比较直接二维测量法(D2D)、解剖M型(AMM)、组织速度成像技术(TVI)及二维斑点追踪技术(STI)评价正常人心肌生物力学参数及其与心功能相关关系的方法,比较他们在临床运用过程优点及存在问题。方法:分别应用D2D、AMM、TVI及STI测量并比较40例正常人收缩、舒张期心肌在长轴方向、短轴和圆周方向的心脏生物力学参数。结果:D2D显示:正常人收缩期纵向应变(LS)及应变率(LSR):下壁>后间隔>前间隔>后壁>前壁>侧壁(P>0.05);收缩期LS、LSR与左室射血分数(LVEF)相关系数(r)分别为-0.523及-0.550。AMM显示:正常人收缩末期径向应变(RS)及径向应变率(RSR)游离壁大于间隔:收缩期RS、RSR与左LVEF(r)分别为0.533及0.495。TVI显示:收缩期LS:心尖段<基底段、中间段(P<0.05);舒张早期LS中间段>基底段>心尖段;舒张晚期LS心尖段<基底段、中间段(P<0.05);收缩期LS、LSR与LVEF(r)分别为-0.562及-0.550。STI显示:收缩期LS从基底段到心尖段逐步递增;左室扭转运动表现为心底部顺时针旋转和心尖部逆时针旋转,心脏整体表现为心动周期内逆时针方向为主的扭转运动。心肌收缩期平均LS及LSR与左室收缩功能参数间r的绝对值均超过0.55。结论:D2D通过直接测量左室长轴方向心肌长度的变化,间接计算LS与LSR;AMM克服了M型超声测量的角度限制,比较适合体位不合作的患者;TVI适合评价长轴方向室壁运动特征;STI对二维图像的超声斑点回声进行逐帧追踪,可以更准确测量局部室壁V、S等参数,定量评价局部心肌的收缩和舒张功能,测量参数与传统超声测量LVEF相关性较好,但设备要求较高。

AIM： To investigate and compare the methods of direct two-dimensional measurements （D2D）, anatomic M-mode method （AMM）, tissue velocity imaging （TVI） and 2D speckle tracking technology （STI） in evaluation of normal myocardial biomechanical characteristics and their relationship with cardiac functions. METHODS： Forty healthy volunteers were selected and routinely evaluated by 2D and M-mode-echocardiography. Then, left ventricular biomechanical parameters including strain （S）and strain rate （SR） during systole and diastole were measured, respectively, by D2D, AM, TVI and STI in real-time or off-line by Philips Sonos IE33 and GE Vivid 7. RESULTS： D2D： The correlation coefficient between the systolic LS, LSR and the LVEF was - 0. 523 and - 0. 550, respectively. For AMM, the correlation coefficient between the systolic RS, RSR and the LVEF was O. 533 and 0. 495, respectively. The overall characteristics of the peak diastolic RS and RSR of the short axis in normal subject were the same ： the free wall was greater than the septal wall, with statistical difference between the septal and posterior walls （P 〈 0.05）. For TVI, the early diastolic LS of the middle segment was 〉 the basal segment 〉 the apical segment and the late diastolic LS of the apical segment was less than that of the basal segment and the middle segment （P 〈 O. 05 ）. The correlation coefficient between the systolic LS, LSR and the LVEF was - 0. 562 and - O. 550, respectively. For STI, the systolic LS of the entire segments in the long axis view of the left ventricle was increased from the basal segment to the apical seg- ment. The absolute value of the correlation coefficients between the systolic S, SR and the LV systolic functional parameters were all 〉 0. 55. CONCLUSION： D2D can measure the circumference of the endocardial and epicardial layers of systolic and diastolic along the short axis, as well as the length of the long axis, thus indirectly obtaining the LS and LSR. AMM can freely move the M-mode sample line within the limit of angles and is suitable for patients with uncooperative position. TVI can be used to quantitatively measure the myocardial S of the local wall directly and is suitable for evaluating the movement feature of the wall by the long axis. STI can measure the myocardial LS and LSR of the local wall more accurately and evaluate regional myocardial systolic and diastolic function. Correlation of the parameters and the LVEF measured by the traditional ultrasound method is good with the use of high-quality equipment.