Grey matter magnetization transfer ratio independently correlates with neurological deficit in secondary progressive multiple sclerosis. - Hayton, T.; Furby, J.; Smith, K.; Altmann, D. R.; Brenner, R.; Chataway, J.; Hughes, R. A. C.; Hunter, K.; Tozer, D. J.; Miller, D. H.; Kapoor, R. (Journal of Neurology, 2009)