Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Atlanta, GA 30332-0535, USA.
Ann Biomed Eng. 2013 Feb;41(2):305-15. doi: 10.1007/s10439-012-0651-z. Epub 2012 Sep 11.
Numerical models of the mitral valve have been used to elucidate mitral valve function and mechanics. These models have evolved from simple two-dimensional approximations to complex three-dimensional fully coupled fluid structure interaction models. However, to date these models lack direct one-to-one experimental validation. As computational solvers vary considerably, experimental benchmark data are critically important to ensure model accuracy. In this study, a novel left heart simulator was designed specifically for the validation of numerical mitral valve models. Several distinct experimental techniques were collectively performed to resolve mitral valve geometry and hemodynamics. In particular, micro-computed tomography was used to obtain accurate and high-resolution (39 μm voxel) native valvular anatomy, which included the mitral leaflets, chordae tendinae, and papillary muscles. Three-dimensional echocardiography was used to obtain systolic leaflet geometry. Stereoscopic digital particle image velocimetry provided all three components of fluid velocity through the mitral valve, resolved every 25 ms in the cardiac cycle. A strong central filling jet (V ~ 0.6 m/s) was observed during peak systole with minimal out-of-plane velocities. In addition, physiologic hemodynamic boundary conditions were defined and all data were synchronously acquired through a central trigger. Finally, the simulator is a precisely controlled environment, in which flow conditions and geometry can be systematically prescribed and resultant valvular function and hemodynamics assessed. Thus, this work represents the first comprehensive database of high fidelity experimental data, critical for extensive validation of mitral valve fluid structure interaction simulations.
已经使用二尖瓣的数值模型来阐明二尖瓣的功能和力学。这些模型已经从简单的二维近似发展到复杂的三维全耦合流固耦合模型。然而，到目前为止，这些模型缺乏直接的一对一实验验证。由于计算求解器差异很大，实验基准数据对于确保模型的准确性至关重要。在这项研究中，专门设计了一种新型的左心模拟器，用于验证数值二尖瓣模型。采用了几种不同的实验技术来解决二尖瓣的几何形状和血液动力学问题。特别是，使用微计算机断层扫描来获得准确的高分辨率（39μm 体素）原生瓣膜解剖结构，包括二尖瓣瓣叶、腱索和乳头肌。三维超声心动图用于获得收缩期瓣叶的几何形状。立体数字粒子图像测速法提供了通过二尖瓣的所有三个方向的流体速度，在心脏周期中每 25ms 解析一次。在收缩期峰值时观察到一个强烈的中心充盈射流（V~0.6m/s），平面外速度最小。此外，定义了生理血液动力学边界条件，所有数据都通过中央触发器同步采集。最后，模拟器是一个精确控制的环境，可以系统地规定流动条件和几何形状，并评估瓣膜的功能和血液动力学。因此，这项工作代表了第一个高保真实验数据的综合数据库，对于二尖瓣流固耦合模拟的广泛验证至关重要。
