1. From the Department of Diagnostic Radiology, the First Affiliated Hospital of Xi’an Jiaotong University, 277 West Yanta Road, Xi’an 710061, PR China (C.J., H.L., X.L., M.W., C.L., J.G., J.Y.); and Department of Biomedical Engineering, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, PR China (X.L., J.Y.).