1 From the Departments of Neurosurgery (B.Y., Y.M., L.J.), Vascular Ultrasonography (Y.H.), Cardiovascular Surgery (D.X., K.Z.), and Anesthesiology (L.Z.), Xuanwu Hospital, Capital Medical University, Fengtai, China.
2 From the Departments of Neurosurgery (B.Y., Y.M., L.J.), Vascular Ultrasonography (Y.H.), Cardiovascular Surgery (D.X., K.Z.), and Anesthesiology (L.Z.), Xuanwu Hospital, Capital Medical University, Fengtai, China. liqunjiao@sina.cn.