EP22.12: A multi‐biomarker approach to evaluation of the human pregnant cervix using quantitative ultrasound (QUS) imaging biomarkers

Abstract

To integrate quantitative ultrasound (QUS) biomarkers of changes in cervical softness and extracellular matrix (ECM) organisation from 1st trimester (1T) to 3rd trimester (3T). In pregnant women (n=30) we used shear wave speed estimation (SWS) to measure softness, acoustic backscatter to evaluate ECM microstructural organisation via mean backscattered power difference (mBSPD) and effective scatterer diameter (ESD), and the Nakagami “M” to measure scatterer number density. Parametric and non-parametric tests were used as appropriate to compare differences between parameters and groups. SWS decreased from 1T to 3T [4.09±1.19 m/s (CI: 3.42-4.80) vs 2.13±0.66 m/s (CI: 1.84-2.45), p < 0.0001], suggesting softer tissue in 3T; backscatter anisotropy (mBSPD), was greater in 1T than 3T [4.65±1.72 dB (CI: 3.86-5.62) vs 2.70 ± 1.15 dB(CI: 2.30-3.31), p=0.0061], suggesting less ECM organisation in 3T; effective scatterer diameter (ESD), was larger in 1T than 3T [90±24 μm (CI: 78-97) vs 46±24 μm (CI: 35-56), p < 0.0001], suggesting less ECM organisation in 3T; Nakagami “M” did not vary from 1T to 3T [0.86±0.12, (CI: 0.79-0.92) vs 0.84±0.10, (CI: 0.80-0.89), p=0.80] suggesting no change in collagen concentration from 1T to 3T; and, in 3T ripened cervixes compared to untreated, SWS was lower [1.54±0.31 m/s (CI: 1.37-1.72) vs 2.13±0.66 m/s (CI: 1.84-2.45), p=0.002] but mBSPD unchanged [2.96±1.43 dB (CI: 2.35-3.77) vs 3.14±2.24 dB (CI: 2.51-4.73), p=0.8545], suggesting increased softness without change in ECM organisation. These preliminary results suggest that QUS biomarkers can simultaneously and comprehensively evaluate ECM organisation and tissue softness. They seem consistent with molecular studies in humans and animals that suggest mechanisms of cervical change are different in early compared to late pregnancy. In summary, combined QUS biomarkers may prove valuable for assessing in vivo cervical remodelling in women.