1 Department of Radiology, Yantai Affiliated Hospital of Binzhou Medical Universtiy, No. 717, Jinbu Street, Yantai, Shandong, 264100, China.
2 Department of Radiology, Yantai Affiliated Hospital of Binzhou Medical Universtiy, No. 717, Jinbu Street, Yantai, Shandong, 264100, China. bzmceducn@sina.com.