Prenatal quantification of human foetal lung and liver elasticities between 24 and 39 weeks of gestation using 2D shear wave elastography

Camille Nallet,Lionel Pazart,Chrystelle Vidal,Guillaume Gorincour,Claire Cochet,Emmanuelle Jacquet,Nicolas Mottet,Jean-Patrick Metz

doi:10.1007/s00330-022-08654-1

Abstract

ObjectivesTo quantify and model normal foetal lung and liver elasticities between 24 and 39 weeks of gestation (WG) using two-dimensional shear wave elastography (2D-SWE). To assess the impact of the distance between the probe and the target organ on the estimation of elasticity values.MethodsMeasurements of normal foetal lungs and liver elasticity were prospectively repeated monthly between 24 and 39 WG in 72 foetuses using 2D-SWE. Elasticity was quantified in the proximal lung and in the region inside the hepatic portal sinus. The distance between the probe and the target organ was recorded. Trajectories representing foetal lung and liver maturation from at least 3 measurements over time were modelled.ResultsThe average elasticity for the lung and liver was significantly different from 24 WG to 36 WG (p < 0.01). Liver elasticity increased during gestation (3.86 kPa at 24 WG versus 4.45 kPa at 39 WG). From 24 WG to 32 WG, lung elasticity gradually increased (4.12kPa at 24 WG, 4.91kPa at 28 WG, 5.03kPa at 32 WG, p < 0.002). After 32 WG, lung elasticity decreased to 4.54kPa at 36 WG and 3.94kPa at 39 WG. The dispersion of the average elasticity values was greater for the lung than for the liver (p < 0.0001). Variation in the elasticity values was less important for the liver than for the lung. The values were considered valid and repeatable except for a probe-lung distance above 8cm.ConclusionFoetal lung and liver elasticities evolve differently through gestation. This could reflect the tissue maturation of both organs during gestation.Trial registrationclinicaltrials.gov identifier: NCT03834805Key Points• Prenatal quantification of foetal lung elasticity using 2D shear wave elastography could be a new prenatal parameter for exploring foetal lung maturity.• Liver elasticity increased progressively from 24 weeks of gestation (WG) to 39 WG, while lung elasticity increased first between 24 and 32 WG and then decreased after 32 WG.• The values of elasticity are considered valid and repeatable except for a probe-lung distance above 8cm.

Highlights

Foetal lung development is accompanied by cell proliferation, intense renewal of the extracellular matrix and increased deposits of elastin responsible for changes in tissue biomechanical characteristics during gestation [1]
In a preliminary pilot study, we concluded that quantitative foetal lung and liver stiffness measurements during gestation were feasible using 2D-shear wave elastography (SWE) with acceptable reproducibility [14]. We explored both the foetal lung and liver because the latter has been used as a reference organ to assess foetal lung maturity in several studies using ultrasound or MRI [15–17]
At least 3 ultrasounds with 2D-SWE were available for 72 women giving birth at term to healthy children without respiratory distress syndrome (RDS) (Silverman score < 4)

Summary

Introduction

Foetal lung development is accompanied by cell proliferation, intense renewal of the extracellular matrix and increased deposits of elastin responsible for changes in tissue biomechanical characteristics during gestation [1]. The natural stretching of the foetal lung during gestation is important for regulating matrix cellular differentiation and controlling surfactant synthesis [3]. All these interactions and histological changes supported by the collagen and elastic fibre system influence biomechanical properties and the functioning of the lung. The distance between the probe and deep organs can limit the accurate measurement of SWS. This technique has been used in several organs (liver, breast, placenta, cervix) [7–11], and some studies have reported interesting results regarding the exploration of non-human foetal organs with 2DSWE [12, 13]

Objectives

Methods

Results

Conclusion