1. Department of Ultrasound; Shenzhen Maternity & Child Healthcare Hospital, Southern Medical University; Shenzhen Guangdong China
2. Department of Obstetrics & Gynecology, School of Medicine; University of Connecticut; Farmington CT USA
3. Department of Central Laboratory, Shenzhen Maternity & Child Healthcare Hospital; Southern Medical University; Shenzhen Guangdong China
4. Department of Ultrasound; Maternity & Child Healthcare Hospital of Guangxi Zhuang Autonomous Region; Nanning Guangxi China