1. Department of Radiology, Kyung Hee University Hospital, College of Medicine, Kyung Hee University, 23, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea.
2. Department of Radiology, Kyung Hee University Hospital at Gandong, College of Medicine, Kyung Hee University, Seoul, Republic of Korea.
3. Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.