1. From the Departments of Radiology (X.Y.Z., S.W., X.T.L., Y.P.W., Y.J.S., Y.S.S.) and Gastrointestinal Surgery (L.W., A.W.W.), Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital and Institute, No. 52 Fu Cheng Road, Hai Dian District, Beijing 100142, China.