Corresponding Author

H. Xie

Department of Ultrasonic Medicine, Fetal Medical Center, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China

Co-Correspondence to: N. Wang, Guangzhou Aiyunji Information Technology co., Ltd, Guangdong China; Room 1605, 2# zhongshan six road, Yuexiu District, Guangzhou, Guangdong, China, 510080; E-mail: lynn1014@163.com.

H. Xie, MD, PhD, Department of Ultrasonic Medicine, Fetal Medical Center, First Affiliated Hospital, Sun Yat-sen University, Zhongshan 2nd Road 58#, Guangzhou, Guangdong, China, E-mail: xiehn@mail.sysu.edu.cn