1. Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea.
2. Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
3. Department of Internal Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea.