1. Department of Radiology, Soonchunhyang University, College of Medicine, Gyeonggi-do 420-767, Korea.
2. Department of Radiology, Chosun University Hospital, Gwangju 501-717, Korea.
3. Department of Internal Medicine, Soonchunhyang University, College of Medicine, Gyeonggi-do 420-767, Korea.
4. Department of Anesthesiology and Pain Medicine, Asan Medical Center, Ulsan University College of Medicine, Seoul 138-736, Korea.