1. Department of Diagnostic Radiology, Tuen Mun Hospital; Tuen Mun, Hong Kong
2. Department of Anesthesiology and Pain Medicine, College of Medicine, Asan Medical Center; Seoul, Korea
3. Respiratory and Critical Care Medicine, College of Medicine, Asan Medical Center; Seoul, Korea
4. Neurology, University of Ulsan, College of Medicine, Asan Medical Center; Seoul, Korea