Shun-Fa Hung1, Chih-Chun Wu2, Feng-Chi Chang1, Wan-You Guo1. 1. Department of Radiology, Taipei Veterans General Hospital; National Yang-Ming University, Taipei, Taiwan. 2. Department of Radiology, Taipei Veterans General Hospital; National Yang-Ming University, Taipei, Taiwan. Electronic address: ccwu1005@gmail.com.