An inverse modeling approach for semilunar heart valve leaflet mechanics: exploitation of tissue structure
An inverse modeling approach for semilunar heart valve leaflet mechanics: exploitation of tissue structure
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DOI：
10.1007/s10237-015-0732-7
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发表时间：
2016-08-01
影响因子：
3.5
通讯作者：
Sacks, Michael S.
中科院分区：
文献类型：
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作者：
Aggarwal, Ankush;Sacks, Michael S.
以无创方式确定心脏瓣膜小叶组织的生物力学行为仍然是一个重要的临床目标。虽然3D成像技术的进步已经使活体瓣膜几何数据成为可能，但利用这些信息获取功能信息的最佳方法仍有待建立。在此，我们提出并评估了一种新的基于小叶形状的框架，通过利用组织结构来估计心脏瓣膜表面变形的生物力学行为。我们使用“理想的”体外数据集确定精度水平，其中小叶几何形状、应变、机械行为和纤维结构都是高精度的。通过利用单叶力学行为的简化结构模型，我们能够将每个单叶要确定的参数数量限制为只有两个。这种方法使我们大大减少了计算时间，并且很容易将成本函数可视化，从而指导最小化过程。我们确定图像分辨率和可用成像帧的数量是我们框架准确性的重要组成部分。此外，我们的结果表明，使用我们的框架可以检测纤维结构的差异，从而有机会诊断无症状瓣膜疾病并在其早期阶段开始治疗。最后，当使用平均纤维结构时，我们观察到最终得到的应力-应变响应的良好一致性。这表明，种群平均纤维结构数据可能足以将本框架应用于体内研究，尽管显然仍有许多工作要将本方法扩展到体内问题。
Determining the biomechanical behavior of heart valve leaflet tissues in a noninvasive manner remains an important clinical goal. While advances in 3D imaging modalities have made in vivo valve geometric data available, optimal methods to exploit such information in order to obtain functional information remain to be established. Herein we present and evaluate a novel leaflet shape-based framework to estimate the biomechanical behavior of heart valves from surface deformations by exploiting tissue structure. We determined accuracy levels using an "ideal" in vitro dataset, in which the leaflet geometry, strains, mechanical behavior, and fibrous structure were known to a high level of precision. By utilizing a simplified structural model for the leaflet mechanical behavior, we were able to limit the number of parameters to be determined per leaflet to only two. This approach allowed us to dramatically reduce the computational time and easily visualize the cost function to guide the minimization process. We determined that the image resolution and the number of available imaging frames were important components in the accuracy of our framework. Furthermore, our results suggest that it is possible to detect differences in fiber structure using our framework, thus allowing an opportunity to diagnose asymptomatic valve diseases and begin treatment at their early stages. Lastly, we observed good agreement of the final resulting stress-strain response when an averaged fiber architecture was used. This suggests that population-averaged fiber structural data may be sufficient for the application of the present framework to in vivo studies, although clearly much work remains to extend the present approach to in vivo problems.