1. Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
3. Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
4. Department of Medicine, Yonsei University College of Medicine, Seoul, Korea.