OC138: Power Doppler and fetal organ perfusion

Abstract

To develop a standardized method for quantification of the power Doppler signals recorded from fetal organs, compensating for factors (instrument settings, depth, and attenuation) that can affect the results. The method by Rubin et al. has been modified and fractional moving blood volume (FMBV) was estimated within the standardized region of interest within the fetal lung The method was evaluated in an in vitro model and then applied in an animal experimental model. In fetal sheep, the measurements of FMBV were compared with blood perfusion measurements using radioactive labeled microspheres. A test of the reproducibility of the FMBV estimation was performed by two independent operators in the lungs of 20 human fetuses. Then the method was applied on a clinical material. FMBV was estimated in the lung of 47 normally grown and 25 growth restricted (IUGR) fetuses after 32 weeks of gestation. 1) A high correlation was found between the FMBV and radioactive labeled microspheres in measurement of fetal adrenal gland perfusion (r = 0.90). 2) The reproducibility test gave satisfactory results: Intraclass correlation coefficient 0.92 (95% confidence interval [CI] 0.78–0.96); interclass correlation coefficient 0.70 (95%CI 0.56–0.76), Kappa index 0.82 (95%CI 0.51–0.93). 3) The normal fetuses showed a higher lung FMBV values than the IUGR fetuses (P = 0.003). There was no association between the FMBV and respiratory complications during neonatal period. The power Doppler FMBV method proved to give an estimate of fetal organ blood perfusion. A standardized and reproducible method of examining fetal lung circulation has been developed. The clinical potential of the power Doppler FMBV method, e.g., for prediction of lung hypoplasia, remains to be established.