1. Department of Radiology, Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China
2. Outpatient Department, 77100 Troops, Chinese People's Liberation Army, Chongqing 400020, P.R. China
3. Department of Radiology, Xinan Hospital of Third Military Medical University, Chongqing 400038, P.R. China