Abstract An ultrasound-based approach to characterize the fluid–structure interaction in large arterial vessels is presented. The ultrasound-based data are fed into a new dynamic model accounting for a two-dimensional (2D) stress state, which in turn provides a better estimate of the material elasticity under dynamic loading. In order to validate the semi-empirical model, a compliant, synthetic vessel was subjected to a range of pulsatile and steady flow profiles. Ultrasound imaging was used to capture the flow field through the compliant vessel and its change in diameter over time. Internal pressure was extracted from ultrasound image velocimetry using spatial integration of the Navier–Stokes equation, and used to find the pressure–area relationship. Two constitutive laws describing a one-dimensional expansion of a cylindrical vessel, the Laplace law and one from Olufsen (Am J Physiol-Heart Circul Physiol 276(1):H257–H268, 1999), were also used to estimate the instantaneous elastic modulus. A uniaxial tensile test of the vessel material was performed to provide validation criteria. Under steady flow, the Laplace law predicted the elasticity of the vessel material with 255% error and the results from Olufsen (Am J Physiol-Heart Circul Physiol 276(1):H257–H268, 1999) had an error of 99%. In contrast, our developed 2D stress model predicted the elasticity with less than 10% error. The Laplace law and the Olufsen (Am J Physiol-Heart Circul Physiol 276(1):H257–H268, 1999) model were revealed to be flow-dependent such that the trend of the resultant elastic modulus varied for each pulsatile flow case. However, the 2D stress model showed no flow dependency, presenting consistent elasticity results across all test cases. Graphic abstract

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一种用于表征大动脉血管流体-结构相互作用的基于超声的方法

摘要提出了一种基于超声的方法来表征大动脉血管中的流体-结构相互作用。基于超声的数据被输入到一个新的动态模型中，该模型解释了二维 (2D) 应力状态，从而更好地估计了动态载荷下的材料弹性。为了验证半经验模型，一个符合要求的合成容器经受了一系列脉动和稳定的流动剖面。超声成像用于捕获通过顺应性血管的流场及其直径随时间的变化。使用 Navier-Stokes 方程的空间积分从超声图像测速中提取内部压力，并用于找到压力-面积关系。描述圆柱形容器一维膨胀的两个本构定律，拉普拉斯定律和 Olufsen 定律（Am J Physiol-Heart Circul Physiol 276(1):H257–H268, 1999）也用于估计瞬时弹性模量。进行容器材料的单轴拉伸试验以提供验证标准。在稳定流下，拉普拉斯定律预测血管材料的弹性有 255% 的误差，而 Olufsen（Am J Physiol-Heart Circul Physiol 276(1):H257–H268, 1999）的结果有 99% 的误差。相比之下，我们开发的 2D 应力模型预测弹性的误差小于 10%。拉普拉斯定律和 Olufsen (Am J Physiol-Heart Circul Physiol 276(1):H257–H268, 1999) 模型被揭示为依赖于流量，因此合成弹性模量的趋势因每个脉动流情况而异。然而，二维应力模型没有显示流动相关性，在所有测试用例中呈现一致的弹性结果。图形摘要