1. Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea.
2. Department of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea.
3. Department of Radiology, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT 84112, USA.
4. Siemens Healthcare, Seoul 03737, Korea.
5. Department of Rehabilitation Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea.