1. Department of Radiology, Wan Fang Hospital, Taipei Medical University, Taipei 116, Taiwan.
2. Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
3. Department of Radiology, Dongguk University Gyeongju Hospital, Gyeongju 38067, Korea.
4. Department of Radiology, University of California, Davis, CA 95817, USA.
5. Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.