Keijzer Lana B H, Strachinaru Mihai, Bowen Daniel J, Caenen Annette, van Steen Antonius F W der, Verweij Martin D, de Jong Nico, Bosch Johan G, Vos Hendrik J
IEEE Trans Ultrason Ferroelectr Freq Control. 2020 Aug;67(8):1590-1602. doi: 10.1109/TUFFC.2020.2978299. Epub 2020 Mar 4.
Shear wave speed measurements can potentially be used to noninvasively measure myocardial stiffness to assess the myocardial function. Several studies showed the feasibility of tracking natural mechanical waves induced by aortic valve closure in the interventricular septum, but different echocardiographic views have been used. This article systematically studied the wave propagation speeds measured in a parasternal long-axis and in an apical four-chamber view in ten healthy volunteers. The apical and parasternal views are predominantly sensitive to longitudinal or transversal tissue motion, respectively, and could, therefore, theoretically measure the speed of different wave modes. We found higher propagation speeds in apical than in the parasternal view (median of 5.1 m/s versus 3.8 m/s, , n = 9 ). The results in the different views were not correlated ( r = 0.26 , p = 0.49 ) and an unexpectedly large variability among healthy volunteers was found in apical view compared with the parasternal view (3.5-8.7 versus 3.2-4.3 m/s, respectively). Complementary finite element simulations of Lamb waves in an elastic plate showed that different propagation speeds can be measured for different particle motion components when different wave modes are induced simultaneously. The in vivo results cannot be fully explained with the theory of Lamb wave modes. Nonetheless, the results suggest that the parasternal long-axis view is a more suitable candidate for clinical diagnosis due to the lower variability in wave speeds.
剪切波速度测量有可能被用于无创测量心肌僵硬度以评估心肌功能。多项研究表明，追踪主动脉瓣关闭在室间隔诱发的自然机械波具有可行性，但使用了不同的超声心动图视图。本文系统研究了10名健康志愿者在胸骨旁长轴视图和心尖四腔视图中测量的波传播速度。心尖视图和胸骨旁视图分别主要对纵向或横向组织运动敏感，因此，理论上可以测量不同波模式的速度。我们发现心尖视图中的传播速度高于胸骨旁视图（中位数分别为5.1米/秒和3.8米/秒，n = 9）。不同视图的结果不相关（r = 0.26，p = 0.49），并且与胸骨旁视图相比，在健康志愿者的心尖视图中发现了出乎意料的大变异（分别为3.5 - 8.7米/秒和3.2 - 4.3米/秒）。弹性板中兰姆波的互补有限元模拟表明，当同时诱发不同波模式时，不同的粒子运动分量可以测量到不同的传播速度。体内结果无法用兰姆波模式理论完全解释。尽管如此，结果表明胸骨旁长轴视图由于波速变异性较低，是临床诊断更合适的选择。
