1. From the Department of Neurology, Boston Children’s Hospital (M.E.B.-L.), the Departments of Neurology (M.E.B.-L., M.A.W.), Radiology (O.R.), and Neurosurgery (W.E.B.), Harvard Medical School, and the Departments of Radiology (O.R.), Neurology (M.A.W.), and Neurosurgery (W.E.B.), Massachusetts General Hospital — all in Boston.