Fetal lung power Doppler imaging and velocimetry before and after repeatedbetamethasone treatment

Objectives Semiquantitative evaluation of tissue blood flow in the fetal lu ng before and after betamethasone treatment by means of computer analysis o f power Doppler ultrasound signals. Methods Power Doppler signals were recorded in ten singleton pregnancies wi th imminent premature delivery before and after each of three courses of in tramuscular administration of betamethasone with a 12-day interval between each course. Fixed power Doppler system installations were used. Power Dopp ler images were recorded on S-VHS tape and transmitted for computer analysi s. The mean flow signal intensity was recorded for the fetal lung before an d after betamethasone administration. Blood velocity waveforms were recorde d in intrapulmonary arteries and veins and in the left pulmonary vein using spectral pulsed wave Doppler ultrasound. Results In all cases, power Doppler signals indicated gradually increased v alues after each treatment. The intrapulmonary arteries showed decreased re sistance to flow in all cases. No significant changes were seen in venous b lood flow. Conclusions These results suggest improved blood flow in the fetal lung aft er repeated corticosteroid administration.