Betamethasone treatment and fetal lung perfusion evaluated with color Doppler energy imaging

The aim of this study was semiquantitative evaluation of tissue blood flow in the fetal lung before and after administration of betamethasone. This was carried out by means of computer analysis of ultrasound Doppler signals obtained by the color Doppler energy (CDE) technique. CDE signals were recorded in 20 singleton pregnancies with appropriate growth and imminent preterm delivery between 26 and 33 weeks of gestation. The CDE signal recordings were made before and after intramuscular administration of betamethasone 8 mg/day for 3 days. Fixed preset CDE system control settings for the fetal right lung were used during the examinations. Images from CDE scans were recorded on S-VHS videotape and transmitted for computer analysis of 8-bit images at 256 gray-scale levels. The mean flow signal intensity was recorded for the fetal lung before and after betamethasone administration. Additionally, blood velocity waveforms were measured in the intrapulmonary arteries and veins in the peripheral part of the lung. CDE signals from the fetal lung indicated increased energy values after corticosteroid treatment in 16 cases. In three cases there was no change in CDE signal values, and in one case a fall of the signal value was noted. Blood velocity waveforms from the intrapulmonary arteries showed decreased resistance to flow in 15 cases, increased resistance to flow in four cases and no change in one case. No significant differences in venous blood flow velocities were found. In conclusion, the results suggest that there is an increase in fetal lung blood perfusion after maternal corticosteroid administration.