Poroelastic MRE Reconstructions of Brain Acquired with Intrinsic Activation

Adam J. Pattison¹, Irina M. Perreard², John B. Weaver, ¹², Keith D. Paulsen^1,2

Magnetic resonance elastography has recently shown great promise in measuring the mechanical properties of brain tissue. However, the skull and cerebral meninges dampen much of the intracranial motion that occurs. Utilizing the natural arterial pulsation (called intrinsic activation) that occurs in the brain could allow for a more comfortable and reliable way of measuring mechanical properties of brain tissue. Here, a study consisting of three brains was performed using a phase-contrast gradient echo sequence to measure velocity and, thus, calculate the displacements. Two algorithms, one with linear elastic assumptions and the other with poroelastic assumptions, were used to estimate the shear modulus distribution. Results show that intrinsic activation does provide feasible results and that the poroelastic estimation is more symmetric and uniform than the linear elastic estimation. Also, the poroelastic estimates were consistent amongst the three cases.