Color flow Doppler in a patent ductus arteriosus

The systolic image of the main pulmonary artery (MPA) shows shunt flow across a patent ductus arteriosus (PDA) (panel A). The ductal retrograde flow is seen as a bright mosaic jet superimposed on the normal blue flow in the MPA. Note that color away from the transducer is coded blue and flow towards is red. There is also a very small color jet of pulmonary regurgitation (PR) that is in the center of the pulmonary valve. Color flow image in the four-chamber apical view shows early diastolic inflow to the left side of the heart due to the large left-to-right shunt (panel B).