Atrophy and Shape Changes in Deep Gray Matter in Multiple Sclerosis: A Tensor Based Morphometry

Introduction: We have applied tensor based morphometry (TBM) method to study the atrophy and shape changes of deep gray matter (DGM) structures in 88 Relapsing-Remitting Multiple Sclerosis (RRMS) patients. To improve the accuracy and robustness of morphometry measurement, an unbiased template was constructed from 20 normal brains for group comparison. A symmetric inverse consistent nonlinear registration method was used to co-align T1-weighted images with unbiased template. The strain tensor was then extracted from the deformation field. In addition to quantifying atrophy of DGM structures with Jacobian Determinant (JD), tanh of Geodesic Anisotropy (GA) was calculated to study the shape differences of these structures. Both atrophy and shape changes in several DGM structures were found to be significantly correlated with the extended disability status scale (EDSS).