In Vivo Modeling of Biphasic Mechanics in the Brain: A Poroelastic Constitutive Model with Enhanced Structural Description Approach

• Main Author: Narasimhan, Saramati
• Other Authors: Logan Clements
• Format: Others
• Language: en
• Published: VANDERBILT 2017
• Subjects: Biomedical Engineering
• Online Access: http://etd.library.vanderbilt.edu/available/etd-11202017-103216/

Objective: The purpose of this investigation is to test whether a poroelastic model with enhanced structure could capture in vivo interstitial pressure dynamics in a brain undergoing mock surgical loads. Methods: Using interstitial pressure data from a porcine study, we use an inverse model in order to reconstruct these pressures and estimate material properties of the brain tissue. This is done in four distinct reconstruction parameterizations to isolate the influence of the three features studied. These features are the dural septa, the treatment of the ventricles, and treatment of the brain as a saturated media. Results: The approach demonstrates accurate capturing of the interstitial pressure dynamics, pressure gradients, tissue deformation, and the presence of intracranial pressure compartmentalization. Conclusion: This study demonstrates that in order to capture appropriate pressure compartmentalization, interstitial pressure gradients, pressure transient effects, and deformations within the brain, the proposed boundary conditions and structural enhancement coupled with a heterogeneous description invoking partial saturation was needed. Significance: To our knowledge there has not been a systematic study of the influence of anatomical features within brain models. Also, the quality of interstitial pressure fits shown here has not been seen within previous literature. Lastly, the common assumption of saturated tissue is challenged and the noted compliance related to our fits likely reflects remaining anatomical structures not yet captured.