1. Department of Radiology, School of Medicine, Ewha Womans University, Seoul 07985, Korea.
2. Department of Occupational and Environmental Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.
3. Department of Radiology, Dongguk University Ilsan Hospital, Goyang 10326, Korea.
4. Department of Radiology, Gachon University Gil Medical Center, Incheon 21565, Korea.
5. Department of Pathology, Yonsei University Wonju College of Medicine, Wonju 26426, Korea.