1. From the Department of Neurology and Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Mass (J.Q., J.X., Y.Z., Y.W., X.Z., M.A.M., E.H.L., J.R.S.); and the departments of Neurosurgery (J.X.) and Rheumatology (X.Z.), Huashan Hospital, Shanghai, China.