1. From the Stroke and Cerebrovascular Center (L.L.L., J.B., A.R.D., M.E.B.-L., H.M., M.J.R., C.C.T.), Departments of Neurology (L.L.L., J.B., K.K., M.E.B.-L., M.J.R.), Psychiatry (M.J.R.), and Radiology (A.R.D., M.J.R.), and Division of Hematology/Oncology (H.M., C.C.T.), Boston Children’s Hospital, Harvard Medical School, MA.