1. Department of Radiology, Samsung ChangWon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea.
2. Department of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
3. Division of Cardiology, Cardiac and Vascular Center, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.