1. Department of Ultrasound, Shenzhen Maternity & Child Healthcare Hospital, The First School of Clinical Medicine, Southern Medical University, Shenzhen, China
2. Department of Ultrasound, Xiamen Maternal&Child HealthCare Hospital, Xiamen, China
3. Department of Ultrasound, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
4. Department of Ultrasound, Shenzhen Renai Hospital, Shenzhen, China
5. Department of Ultrasound, Cangxian Hospital, Cangzhou, China
6. Department of Ultrasound, Maternity & Child Healthcare Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
7. Department of Obstetrics & Gynecology, Howard University College of Medicine, Washington, United States