Sixty-six patients with patent ductus arterio-sus (PDA) were prospectively studied by 2-DEand 2-DCE with 106 patients suffering from otherheart diseases as control. In the diagnosis of PDAby 2-DE, the parasternal long axis view ofpulmonary artery, parasternal sagittat view andsuprasternal view were satisfactory concerningtheir sensitivity,specificity and accuracy. Of thethree planes, the best one appeared to be the