1 Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Eonjuro 211, Gangnam-gu, Seoul, South Korea. Electronic address: minapark@yuhs.ac.
2 Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Eonjuro 211, Gangnam-gu, Seoul, South Korea.