Decoupling Uniaxial Tensile Prestress and Waveguide Effects From Estimates of the Complex Shear Modulus in a Cylindrical Structure Using Transverse-Polarized Dynamic Elastography
Decoupling Uniaxial Tensile Prestress and Waveguide Effects From Estimates of the Complex Shear Modulus in a Cylindrical Structure Using Transverse-Polarized Dynamic Elastography
复制标题
使用横向偏振动态弹性成像从圆柱结构中的复剪切模量估计中解耦单轴拉伸预应力和波导效应
DOI：
10.1115/1.4056411
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Royston, Thomas J.
中科院分区：
文献类型：
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作者：
Salehabadi, Melika;Crutison, Joseph;Klatt, Dieter;Royston, Thomas J.
动态弹性成像，无论是基于磁共振、超声还是光学模态，都试图通过无创地测量组织中的机械波运动来重建生物组织的粘弹性特性、因疾病和损伤而改变的特性的定量图。大多数已开发的重建策略都忽略了边界条件，包括导致非零预应力的准静态拉伸或压缩载荷。显着的预应力是目前使用弹性成像技术研究的一些生物组织（例如骨骼肌和心肌、动脉壁和角膜）的功能作用所固有的。在本文中，我们对一种受肌肉弹性成像启发但可推广到其他应用的配置进行了分析和实验研究。超弹性聚合物模型圆柱体沿轴向静态伸长，同时测量其对横向偏振振动激励的响应。我们使用计算有限元模拟和磁共振弹性成像测量来检查这种肌肉样组织模型中单轴预应力和波导效应之间的相互作用。由预应力引起的有限变形与波导效应相结合，产生了通过坐标变换方法预测的结果，该方法先前已用于简化使用弹性成像的各向异性重建。在这里，该方法估计与非均匀预应力条件无关的材料粘弹性特性，而不需要对这些应力条件有深入的了解。
Dynamic elastography, whether based on magnetic resonance, ultrasound, or optical modalities, attempts to reconstruct quantitative maps of the viscoelastic properties of biological tissue, properties altered by disease and injury, by noninvasively measuring mechanical wave motion in the tissue. Most reconstruction strategies that have been developed neglect boundary conditions, including quasi-static tensile or compressive loading resulting in a nonzero prestress. Significant prestress is inherent to the functional role of some biological tissues currently being studied using elastography, such as skeletal and cardiac muscle, arterial walls, and the cornea. In the present article a configuration, inspired by muscle elastography but generalizable to other applications, is analytically and experimentally studied. A hyperelastic polymer phantom cylinder is statically elongated in the axial direction while its response to transverse-polarized vibratory excitation is measured. We examine the interplay between uniaxial prestress and waveguide effects in this muscle-like tissue phantom using computational finite element simulations and magnetic resonance elastography measurements. Finite deformations caused by prestress coupled with waveguide effects lead to results that are predicted by a coordinate transformation approach that has been previously used to simplify reconstruction of anisotropic properties using elastography. Here, the approach estimates material viscoelastic properties that are independent of the nonhomogeneous prestress conditions without requiring advanced knowledge of those stress conditions.