Using Multicompartmental Poroelasticity to Explore Brain Biomechanics and Cerebral Diseases

Numerical methods and simulations offer the prospect of improved clinically relevant predictive information, enabling more efficient use of resources for designing treatment protocols, risk assessment and urgently needed management of long term care systems for a wide spectrum of brain disorders. An extended poroelastic model of perfused parenchymal tissue coupled with separate workflows incorporating subject-specific meshes, permeability tensor maps and cerebral blood flow variability is outlined in this work. This consolidated pipeline is also used to provide subject-specific boundary conditions for the regions of the cerebroventricular volume responsible for cerebrospinal fluid (CSF) secretion, in addition to the exit sites which allow for the passage of CSF into the intricate drainage pathways of the brain. Subject-specific datasets used in the modelling of this paper were collected as part of a prospective data collection effort. Two cases were simulated involving one female cognitively healthy control (CHC) subject, and one female subject with mild cognitive impairment (MCI) undergoing a period of high activity. Results showed visibly reduced blood perfusion, clearance of CSF/interstitial fluid (ISF), CSF/ISF accumulation and drainage in the MCI case. Interestingly, peak aqueductal velocity was higher in the MCI case (1.80 cm/s compared to 0.35 cm/s).