1. Department of Radiology, Kunming Medical University and The Second Affiliated Hospital, Kunming, Yunnan 650500, P.R. China
2. Department of Urology, The First Affiliated Hospital of The Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P.R. China
3. Department of Radiology, Kunming Children's Hospital, Kunming, Yunnan 650034, P.R. China
4. Department of Radiology, Kunming Medical University and The Third Affiliated Hospital, Kunming, Yunnan 650500, P.R. China