1 Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
2 Department of Radiology, National Cancer Center, Gyeonggi-do, Republic of Korea.
3 Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. Electronic address: sykimrad@amc.seoul.kr.