Viscoelastic Modulus Reconstruction Using Time Harmonic Vibrations
Viscoelastic Modulus Reconstruction Using Time Harmonic Vibrations
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DOI：
10.3846/13926292.2015.1117531
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发表时间：
2015-11-02
影响因子：
1.8
通讯作者：
Zhou, Liangdong
中科院分区：
文献类型：
--
作者：
Ammari, Habib;Seo, Jin Keun;Zhou, Liangdong
本文提出了一种新的迭代重建方法，通过内部测量组织中的位移场来提供高分辨率的剪切模量和粘度图像。为了解决反问题，我们计算的最小二乘差异功能的剪切模量和剪切粘度的Frechet导数。建议的迭代重建方法，使用此Frechet导数不需要任何微分的位移数据的全各向同性线性粘弹性模型，而标准的代数反演方法需要至少双重微分。由于最小化问题是不适定的和高度非线性的，这种基于伴随的优化方法需要一个非常匹配的初始猜测。我们有一个很好的初步猜测。数值实验表明，对于匹配良好的初始猜测，该方法大大提高了重建的粘弹性图像的质量。
This paper presents a new iterative reconstruction method to provide high-resolution images of shear modulus and viscosity via the internal measurement of displacement fields in tissues. To solve the inverse problem, we compute the Frechet derivatives of the least-squares discrepancy functional with respect to the shear modulus and shear viscosity. The proposed iterative reconstruction method using this Frechet derivative does not require any differentiation of the displacement data for the full isotropic linearly viscoelastic model, whereas the standard algebraic inversion method requires at least double differentiation. Because the minimization problem is ill-posed and highly nonlinear, this adjoint-based optimization method needs a very well-matched initial guess. We find a good initial guess. For a well-matched initial guess, numerical experiments show that the proposed method considerably improves the quality of the reconstructed viscoelastic images.