1. Department of Radiology, Tianjin Third Central Hospital, Tianjin 300170, P.R. China
2. Department of Radiology, Shengli Oilfield Central Hospital, Dongying, Shandong 257034, P.R. China
3. Department of Pathology, Shengli Oilfield Central Hospital, Dongying, Shandong 257034, P.R. China