1. From the Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, ON (N.D., I.Y., M.S., R.A., D.M., G.d.V., M.M.); Division of Neuroradiology, Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON (P.M., M.S.); Department of Diagnostic Imaging, Toronto Western Hospital, ON (D.M.); and Division of Neurology, Lucile Packard Children’s Hospital Stanford, CA (J.E.).