RT Journal Article SR Electronic T1 MR Imaging of Gray Matter Involvement in Multiple Sclerosis: Implications for Understanding Disease Pathophysiology and Monitoring Treatment Efficacy JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology DO 10.3174/ajnr.A1944 A1 M. Filippi A1 M.A. Rocca YR 2009 UL http://www.ajnr.org/content/early/2009/12/31/ajnr.A1944.abstract AB