Contribution
Greatly appreciated for the supports from Prof. Li, who obtained the 2D echocardiographic images, and participated in the analysis, interpretation and statistics of date with me, as well as critical revision. Xiuxiu Cui and Huaying Bo contributed equally to this article. Also thanks for the help of Dong Yu, MD, Ying Wang, MD, Ying Li, MD, Wenxing Chang, MD, Tingting, Yu, MD, approval of the article. Those authors are all from Department of Ultrasound, the Second Affiliated Hospital of Dalian Medical University, Dalian, China.