1. Department of Vascular Ultrasonography, Xuanwu Hospital, Capital Medical University, Beijing, China
2. Center of Vascular Ultrasonography, Beijing Institute of Brain Disorders, Beijing, China
3. Division of Vascular Surgery and Endovascular Therapy, Department of Surgery, Yale School of Medicine, New Haven, CT, USA
4. Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China