Characterization of the Highly Nonlinear and Anisotropic Vascular Tissues from Experimental Inflation Data: A Validation Study Toward the Use of Clinical Data for In-Vivo Modeling and Analysis
| Autor: | Bahar Fata, Daniel R. Einstein, Kinon Chen |
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| Rok vydání: | 2008 |
| Předmět: |
Materials science
Quantitative Biology::Tissues and Organs Physics::Medical Physics Finite Element Analysis Biomedical Engineering Article Transverse isotropy Tensile Strength Pressure Humans Computer Simulation Anisotropy Elastic modulus business.industry Models Cardiovascular Internal pressure Structural engineering Mechanics Covariance Elasticity Finite element method Nonlinear system Nonlinear Dynamics Hyperelastic material Blood Vessels Collagen Stress Mechanical business |
| Zdroj: | Annals of Biomedical Engineering. 36:1668-1680 |
| ISSN: | 1573-9686 0090-6964 |
| Popis: | We study whether an inverse modeling approach is applicable for characterizing vascular tissue subjected to various levels of internal pressure and axial stretch that approximate in-vivo conditions. To compensate for the limitation of axial-displacement/pressure/diameter data typical of clinical data, which does not provide information about axial force, we propose to constrain the ratio of axial to circumferential elastic moduli to a typical range. Vessel wall constitutive behavior is modeled with a transversely isotropic hyperelastic equation that accounts for dispersed collagen fibers. A single-layer and a bi-layer approximation to vessel ultrastructure are examined, as is the possibility of obtaining the fiber orientation as part of the optimization. Characterization is validated against independent pipette-aspiration biaxial data on the same samples. It was found that the single-layer model based on homogeneous wall assumption could not reproduce the validation data. In contrast, the constrained bi-layer model was in excellent agreement with both types of experimental data. Due to covariance, estimations of fiber angle were slightly outside of the normal range, which can be resolved by predefining the angles to normal values. Our approach is relatively invariant to a constant or a variable axial response. We believe that it is suitable for in-vivo characterization. |
| Databáze: | OpenAIRE |
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