1Department of Anaesthesiology and Pain Medicine, Asan Medical Center, Ulsan University College of Medicine, Seoul, Korea.
2 Assistant Professor, Department of Radiology, Soonchunhyang University College of Medicine, Bucheon, Korea
3Professor
4Assistant Professor, Department of Anaesthesiology and Pain Medicine and Anaesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea