Zaiming Lu1, Qiyong Guo2, Aizhong Shi1, Feng Xie1, Qingjie Lu1. 1. Department of Radiology, China Medical University Shengjing Hospital, 36 Sanhao Street, Heping District, Shenyang, 110004, Liaoning Province, China. 2. Department of Radiology, China Medical University Shengjing Hospital, 36 Sanhao Street, Heping District, Shenyang, 110004, Liaoning Province, China. qiyongguo@yahoo.cn.