fig20

Figure 20. A composite of video images is put together to illustrate the technique of Doppler sampling to detect obstruction in the pulmonary artery on the left side and descending aorta following five-loop coil closure of ductus arteriosus. (A) shows Doppler sampling of the main pulmonary artery (MPA) while (B) illustrates sampling from the left pulmonary artery (LPA). Similar Doppler velocity magnitudes in (A and B) suggest that there is no obstruction in the LPA. (C) shows Doppler sampling of the descending aorta (DAO) proximal the coil while (D) samples DAO distal to the coil. Equal Doppler velocity magnitudes in (C and D) indicate no obstruction in the DAO. Color flow and continuous wave Doppler recordings through the LPA and DAO were also secured in each patient (not shown). No abnormalities in the color Doppler flow were seen (not shown). Reproduced from Ref.^[68].