1 Department of Radiology, Seoul National University Hospital, Seoul, South Korea; Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea.
2 Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea; Department of Radiology, Seoul National University Bundang Hospital, Seongnam-si, Gyeonggi-do, South Korea. Electronic address: kyung8404@gmail.com.