[1] Univ British Columbia, Med, Vancouver, BC, Canada
[2] Univ British Columbia, Radiol, Vancouver, BC, Canada
[3] Kings Coll London, Inst Psychiat Psychol & Neurosci, Neuroimaging, London, England
[4] Univ Toronto, Radiat Oncol, Toronto, ON, Canada
[5] Swiss Fed Inst Technol, Informat Technol & Elect Engn, Zurich, Switzerland
[6] Univ Hosp Zurich, Neurol, Neuroimmunol & Multiple Sclerosis Res, Zurich, Switzerland
[7] Heidelberg Univ, Heidelberg, Germany
[8] Martin Luther Univ Halle Wittenberg, Inst Phys, Halle, Germany
[9] Univ British Columbia, Phys & Astron, Vancouver, BC, Canada