[1] Univ Hong Kong, Dept Diagnost Radiol, Hong Kong, Hong Kong, Peoples R China
[2] Univ Virginia, Dept Neurosurg, Charlottesville, VA 22908 USA
[3] Univ Virginia, Dept Radiol, Neuroradiol Div, Charlottesville, VA 22908 USA
[4] Univ Virginia, Dept Med, Charlottesville, VA 22908 USA
[5] City Univ Hong Kong, Dept Management Sci, Hong Kong, Hong Kong, Peoples R China