Chun-Chun Liu1, Yuan-Chun Huang2, Pin-Hung Yeh3. 1. Department of Anesthesiology, Changhua Christian Hospital, Changhua, Taiwan. Electronic address: 180309@cch.org.com. 2. Department of Radiology, Changhua Christian Hospital, Changhua, Taiwan. Electronic address: 129900@cch.org.tw. 3. Department of Anesthesiology, Changhua Christian Hospital, Changhua, Taiwan. Electronic address: b94401055@ntu.edu.tw.