1. Department of Radiology, Seoul National University Bundang Hospital, Gyeonggi-do 436-707, Korea.
2. Department of Thoracic Surgery, Seoul National University Bundang Hospital, Gyeonggi-do 436-707, Korea.
3. Department of Internal Medicine, Division of Cardiology, Seoul National University Bundang Hospital, Gyeonggi-do 436-707, Korea.
4. Department of Radiology, Soonchunhyang University Bucheon Hospital, Bucheon 420-767, Korea.
5. Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Clinical Research Institute, Seoul National University Hospital, Seoul 110-744, Korea.