[1] Tuen Mun Hosp, Dept Diagnost Radiol, Tuen Mun, Hong Kong, Peoples R China
[2] Singapore Gen Hosp, Dept Diagnost Radiol, Singapore 0316, Singapore
[3] Tuen Mun Hosp, Dept Neurosurg, Hong Kong, Hong Kong, Peoples R China
[4] Hong Kong Polytech Univ, Dept Optometry & Radiog, Hong Kong, Hong Kong, Peoples R China