Multiregional viscoelastic characterization of the corona radiata in the sagittal plane of the porcine brain

Detailed finite element (FE) models are used as promising tools to investigate traumatic brain injuries, although their accuracy is strongly dependent on the characterization of the mechanical behaviors of the different anatomic structures in the brain. In some cases, when the FE models require finer spatial resolution, the heterogeneous and anisotropic corona radiata cannot be taken as a homogeneous whole body. In this work, indentation experiments were conducted on the anterior, superior, and posterior regions of the corona radiata in the sagittal plane. To determine the parameters available for computational modeling purposes, a linear viscoelastic model using the Boltzmann hereditary integral was fitted to the force-time data of the three regions. In the indentation tests, the superior region appeared to be the stiffest, while no significant differences were observed between the anterior and posterior regions until the viscoelastic tissue reached equilibrium. During the period of relaxation, statistical comparisons among the different regions indicated significant differences between the superior and anterior regions, and between the superior and posterior regions. This work complements existing investigations into the anatomic heterogeneity of the brain, and contributes toward improving the spatial resolution of future computational models.