1Diagnostic Radiology, The University of Hong Kong, Hong Kong, Hong Kong, 2Philips Healthcare, Hong Kong, Hong Kong, Hong Kong, 3Biomedical Imaging, University of Malaya, Kuala Lumpur, Malaysia, 4School of Biomedical Sciences, The University of Hong Kong, Hong Kong, Hong Kong, 5Neuropsychology and Applied Cognitive Neuroscience Laboratory, Chinese Academy of Sciences, Beijing, China, People's Republic of, 6Medicine, Queen Mary Hospital, Hong Kong, Hong Kong