ABSTRACT
A unique three-dimensional (3D) computational multiscale modeling approach is proposed to investigate the influence of presence of microcalcification particles on the stress field distribution in the thin cap layer of a coronary atherosclerotic vulnerable plaque system. A nested 3D modeling analysis framework spanning the multiscale nature of a coronary atherosclerotic vulnerable plaque is presented. At the microscale level, a micromechanical modeling approach, which is based on computational finite-element (FE) representative unit cell, is applied to obtain the homogenized nonlinear response of the calcified tissue. This equivalent response effectively allows the integration of extremely small microcalcification inclusions in a global biomechanical FE model. Next, at the macroscale level, a 3D patient-based fluid-structure interaction FE model, reconstructing a refined coronary artery geometry with calcified plaque lesion, is generated to study the mechanical behavior of such multi-component biomechanical system. It is shown that the proposed multiscale modeling approach can generate a higher resolution of stress and strain field distributions within the coronary atherosclerotic vulnerable plaque system and allow the assessment of the local concentration stress around the microcalcifications in plaque cap layers. A comparison of stress field distributions within cap layers with and without inclusion of microcalcifications is also presented.
Subject(s)
Coronary Artery Disease/physiopathology , Plaque, Atherosclerotic/physiopathology , Atherosclerosis/physiopathology , Biomechanical Phenomena , Calcinosis/pathology , Computer Simulation , Coronary Artery Disease/diagnostic imaging , Coronary Vessels/pathology , Elasticity , Finite Element Analysis , Humans , Imaging, Three-Dimensional , Models, Cardiovascular , Nonlinear Dynamics , Plaque, Atherosclerotic/diagnostic imaging , Pressure , Stress, Mechanical , X-Ray MicrotomographyABSTRACT
A new three-dimensional (3D) multiscale micromechanical model has been suggested as adept at predicting the overall linear anisotropic mechanical properties of a vertebral trabecular bone (VTB) highly porous microstructure. A nested 3D modeling analysis framework spanning the multiscale nature of the VTB is presented herein. This hierarchical analysis framework employs the following micromechanical methods: the 3D parametric high-fidelity generalized method of cells (HFGMC) as well as the 3D sublaminate model. At the nanoscale level, the 3D HFGMC method is applied to obtain the effective elastic properties of a representative unit cell (RUC) representing the mineral collagen fibrils composite. Next at the submicron scale level, the 3D sublaminate model is used to generate the effective elastic properties of a repeated stack of multilayered lamellae demonstrating the nature of the trabeculae (bone-wall). Thirdly, at the micron scale level, the 3D HFGMC method is used again on a RUC of the highly porous VTB microstructure. The VTB-RUC geometries are taken from microcomputed tomography scans of VTB samples harvested from different vertebrae of human cadavers [Formula: see text]. The predicted anisotropic overall elastic properties for native VTBs are, then, examined as a function of age and sex. The predicted results of the VTBs longitudinal Young's modulus are compared to reported values found in the literature. The proposed 3D nested modeling analysis framework provides a good agreement with reported values of Young's modulus of single trabeculae as well as for VTB-RUC in the literature.
