Two-dimensional ultrasound shear wave elastography: an effective method for assessing fetal rabbit lung maturity.

Abstract

To investigate the correlation of fetal lung maturity (FLM) and its stiffness obtained by two-dimensional shear wave elastography (2D-SWE) in rabbits. In 50 fetal rabbits (23-30 days gestation), lung and liver elasticity were measured by 2D-SWE. After cesarean section, dipalmitoylphosphatidylcholine (DPPC) concentration in alveolar lavage fluid and lung interstitial ratio were assessed. Partial correlation analysis was then performed to examine the correlation of fetal lung elasticity/lung-to-liver elasticity (LLE) ratio with DPPC content and with interstitial ratio, respectively. Fetal lung and liver 2D-SWE measurements showed good consistency. Fetal lung elasticity and LLE ratio were strongly negatively correlated with DPPC (r = -0.866 [95% CI -0.928, -0.757] and -0.840 [-0.914, -0.714], P < 0.001) and slightly reduced after controlling for interstitial ratio (r = -0.727 [-0.848, -0.534] and -0.672 [-0.815, -0.453], P < 0.001). Conversely, strong positive correlations with the interstitial ratio (r = 0.757 [0.580, 0.865] and 0.763 [0.590, 0.869], P < 0.001) decreased to moderate levels after adjusting for DPPC (r = 0.446 [0.151, 0.667] and 0.471 [0.183, 0.685], P < 0.01). 2D-SWE may serve as a useful non-invasive tool for predicting FLM in rabbits, providing a basis for further studies on human FLM. Key Message: Two-dimensional shear wave elastography (2-DSWE) correlates strongly with surfactant content in fetal lungs, offering a potential non-invasive biomarker of functional lung maturity to address the clinical need for predicting neonatal respiratory readiness. Novelty: We provide the first quantitative evidence that 2D-SWE values reflect biochemical (surfactant) more closely than structural maturation, redefining its role in perinatal assessment. Significance & Impact: 2D-SWE may serve as a novel, non-invasive ultrasound modality for assessing fetal lung maturity. These preclinical findings suggest that it might potentially aid in RDS risk assessment, potentially laying a certain foundation for future clinical research.