1 Department of Neurology, MS Center Amsterdam, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, Netherlands. Electronic address: j.killestein@amsterdamumc.nl.
2 Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Department of Neuroradiology, Berlin, Germany.