Effect of axonal fiber architecture on mechanical heterogeneity of the white matter—a statistical micromechanical model. Issue 1 (27th January 2022)

• Record Type: Journal Article
• Authors: Hoursan, Hesam; Farahmand, Farzam; Ahmadian, Mohammad Taghi
• Is Part Of: Computer methods in biomechanics and biomedical engineering. Volume 25:Issue 1(2022)
• Page Start: 27
• Page End: 39
• Publication Date: 2022-01-27
• Subjects: Statistical micromechanical model -- fractional anisotropy -- embedded element technique -- heterogeneity -- fiber dispersion; Biomechanics -- Data processing -- Periodicals; Biomedical engineering -- Periodicals; Biomechanics -- Periodicals; Biomedical Engineering -- methods -- Periodicals; Computing Methodologies -- Periodicals; 612.7
• DOI: 10.1080/10255842.2021.1927000
• Languages: English
• ISSNs: 1025-5842

Abstract

Abstract: A diffusion tensor imaging (DTI) -based statistical micromechanical model was developed to study the effect of axonal fiber architecture on the inter- and intra-regional mechanical heterogeneity of the white matter. Three characteristic regions within the white matter, i.e., corpus callosum, brain stem, and corona radiata, were studied considering the previous observations of locations of diffuse axonal injury. The embedded element technique was used to create a fiber-reinforced model, where the fiber was characterized by a Holzapfel hyperelastic material model with variable dispersion of axonal orientations. A relationship between the fractional anisotropy and the dispersion parameter of the hyperelastic model was used to introduce the statistical DTI data into the representative volume element. The FA-informed statistical micromechanical models of three characteristic regions of white matter were developed by deriving the corresponding probabilistic measures of FA variations. Comparison of the model predictions and experimental data indicated a good agreement, suggesting that the model could reasonably capture the inter-regional heterogeneity of white matter. Moreover, the standard deviations of experimental results correlated well with the model predictions, suggesting that the model could capture the intra-regional mechanical heterogeneity for different regions of white matter.