1. Department of Internal Medicine, Yeouido St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
2. Department of Medical Statistics, College of Medicine, The Catholic University of Korea, Seoul, Korea.
3. Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
4. Department of Radiology, Yeouido St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
5. Department of Internal Medicine, St. Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.