[1] Natl Univ Heart Ctr Singapore, Dept Cardiol, 1E Kent Ridge Rd,NUHS Tower Block Level 9, Singapore 119228, Singapore
[2] Natl Univ Singapore, Yong Loo Lin Sch Med, Dept Med, Singapore 119228, Singapore
[3] Natl Univ Hlth Syst, Dept Med, Div Neurol, Singapore 119228, Singapore
[4] Natl Univ Hlth Syst, Dept Diagnost Imaging, Div Intervent Radiol, Singapore 119228, Singapore