作者单位:Alfred Hosp, Dept Neurosurg, Melbourne, Vic, Australia[1]Alfred Hosp, Dept Radiol, Melbourne, Vic, Australia[2]Harvard Med Sch, Div Neurosurg, Beth Israel Deaconess Med Ctr, Boston, MA 02115 USA[3]Harvard Med Sch, Div Neurol, Beth Israel Deaconess Med Ctr, Boston, MA USA[4]