Atrophy of the brain grey matter (GM) is an accepted and important feature of multiple sclerosis (MS). However, its accurate measurement is hampered by various technical, pathological and physiological factors. As a consequence, it is challenging to investigate the role of GM atrophy in the disease process as well as the effect of treatments that aim to reduce neurodegeneration. In this paper we discuss the most important challenges currently hampering the measurement and interpretation of GM atrophy in MS. The focus is on measurements that are obtained in individual patients rather than on group analysis methods, because of their importance in clinical trials and ultimately in clinical care. We discuss the sources and possible solutions of the current challenges, and provide recommendations to achieve reliable measurement and interpretation of brain GM atrophy in MS.
Keywords: BET, brain extraction tool; Brain atrophy; CNS, central nervous system; CTh, cortical thickness; DGM, deep grey matter; DTI, diffusion tensor imaging; FA, fractional anisotropy; GM, grey matter; Grey matter; MRI, magnetic resonance imaging; MS, multiple sclerosis; Magnetic resonance imaging; Multiple sclerosis; TE, echo time; TI, inversion time; TR, repetition time; VBM, voxel-based morphometry; WM, white matter.