1. Department of Radiology, Seoul National University College of Medicine, 101 Daehak-ro Jongno-gu, Seoul 03080, Korea.
2. Department of Radiology, Naval Pohang Hospital, Pohang, Korea.
3. Department of Nuclear Medicine, Armed Forces Daejeon Hospital, Daejeon, Korea.
4. Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul, Korea.
5. Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY.