Chih-Wei Chen1, Fu-Zong Wu2. 1. Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; Faculty of Medicine, School of Medicine, National Yang Ming University, Taipei, Taiwan. 2. Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; Faculty of Medicine, School of Medicine, National Yang Ming University, Taipei, Taiwan. Electronic address: cmvwu1029@gmail.com.