1. From the Danish Multiple Sclerosis Center (M.R.E., J.T., R.H.H.H., H.H.C., F.S.), Department of Neurology, Copenhagen University Hospital - Rigshospitalet, Glostrup; Danish Research Centre for Magnetic Resonance (H.L., H.R.S.), Copenhagen University Hospital - Amager and Hvidovre; Department of Clinical Medicine (H.R.S.), University of Copenhagen; and Department of Neurology (H.R.S.), Copenhagen University Hospital - Bispebjerg and Frederiksberg, Denmark.