1. Department of Ultrasound, Fujian Medical University Xiamen Humanity Hospital, Xiamen, Fujian 361006, China
2. Department of Ultrasound, Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian 361004, China
3. National Demonstration Center for Experimental Electronic Information Education, Xiamen University, Xiamen, Fujian 361004, China