病例特异性非线性颈动脉力学的FSI建模及出口边界条件的作用
FSI modeling of case-specific nonlinear carotid artery mechanics and the role of outlet boundary conditions
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中文总结 AI 辅助
本研究将线性弹性FSI框架扩展至非线性应变依赖性动脉壁力学，验证了应变依赖性杨氏模量在平衡实施与生理保真度上的可行性，并揭示了阻力型出口边界条件在患者特异性建模中的不足。
中文摘要 AI 辅助
顺应性动脉壁力学对颈动脉（CA）中的Windkessel效应有贡献，对心血管疾病（如动脉粥样硬化）的血流动力学模式和表面剪切指标有显著影响。在本研究中，我们将线性弹性流体-结构相互作用（FSI）框架扩展，以考虑非线性应变依赖性壁行为。该模型纳入了从硅胶体模拉伸试验中推广的杨氏模量，以捕捉动脉组织的非线性应力-应变关系。最终的计算模型采用阻力型边界条件和体外测量的应力-应变关系，并针对体外评估的硅胶颈动脉体模以及已发表的关于颈动脉分叉处子支血流分配的临床数据进行了验证。为了更好地反映生理条件，我们的模型随后被扩展以纳入患者特异性几何结构的预应力及临床测量的应力-应变关系，并随后针对临床颈动脉数据进行了验证。本研究证明了应变依赖性杨氏（弹性）模量作为增强线性弹性框架准确表征动脉壁生理非线性力学能力的一种手段的可行性，在实施工作与生理保真度之间取得了平衡。该方法产生了真实的应变、体积膨胀行为和非线性压力-体积关系。此外，研究揭示了适当出口边界条件的重要性以及阻力型边界条件在患者特异性建模中的不足，导致非生理性压力分布和非生理性时间血流分配。
英文摘要
Compliant arterial wall mechanics, contributing to the Windkessel effect in the carotid artery (CA), have significant impact on hemodynamic patterns and surface shear indicators for cardiovascular diseases, e.g. atherosclerosis. In this study, we extend the linear elastic Fluid-Structure Interaction (FSI) framework to account for nonlinear strain-dependent wall behavior. The model incorporates a Young's modulus generalized from tensile tests on silicone phantoms to capture the nonlinear stress-strain relation of arterial tissue. The final computational model, using a resistance-type boundary condition and in vitro measured stress-strain relation is validated against both, in vitro assessed silicon CA phantom as well as published clinical data on the flow splitting to the daughter branches in CA bifurcations. To better reflect physiological conditions, our model is subsequently extended to incorporate prestress of patient-specific geometries, and clinically measured stress-strain relations, followed by validation against clinical CA data. The present study demonstrates the feasibility of strain-dependent Young's (elastic) modulus as a means to enhance the capacity of the linear elastic framework to accurately represent the physiologically nonlinear mechanics of arterial walls, striking a balance between implementation effort and physiological fidelity. This approach yields realistic strains, volumetric inflation behavior and nonlinear pressure-volume relationships. Furthermore, the study reveals the importance of proper outlet boundary conditions and the shortcomings of resistance-type boundary condition in patient-specific modeling, leading to non-physiological pressure profiles and non-physiological temporal flow splitting.
发表机构
- University of Kaiserslautern-Landau（凯泽斯劳滕-兰道大学）
- University of Stuttgart（斯图加特大学）
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