1. Department of Computed Tomography and Magnetic Resonance, Children's Hospital of Hebei Province, Shijiazhuang, Hebei 050031, P.R. China
2. Key Laboratory of Spectral Imaging Technology Chinese Academy of Science, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaanxi 710119, P.R. China
3. Department of Radiology, Children's Hospital of Hebei Province, Shijiazhuang, Hebei 050031, P.R. China