1. Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea.
2. Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul 06973, Korea.
3. Department of Radiology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul 04763, Korea.