1. Department of Radiology; Soonchunhyang University Bucheon Hospital; Bucheon Korea
2. Department of Radiology; Soonchunhyang University Seoul Hospital; Seoul Korea
3. Department of Radiology; Chung-Ang University Hospital; Seoul Korea
4. Department of Radiology; Soonchunhyang University Cheonan Hospital; Cheonan Korea
5. Department of Radiology; Soonchunhyang University Gumi Hospital; Gumi Korea