Boundary-Enhanced $U^{2}$-Net for Simultaneous Four-Chamber Segmentation in Transthoracic Echocardiography. - Yuanqin Meng; Shengjie Chai; Haoyu Xiao; Zhaohui Meng; Qingwang Wang; Tao Shen 004 (IEEE J. Biomed. Health Informatics, 2025)