Neuroimaging Clinics of North America have a special 2 part series on MRI and MS:
Multiple Sclerosis, Part I: Background and Conventional MRI. Volume 18, Issue 4, Pages 563-720 (November 2008)
Multiple Sclerosis, Part II: Nonconventional MRI Techniques. Volume 19, Issue 1, Pages 1-132 (February 2009)

This series is edited by Massimo Filippi and contain many articles written by WMSG members.