Quantitative Ultrasound Detects Smooth Muscle Activity at the Cervical Internal Os in Vitro

Abstract

The cervix has two biomechanical functions: to remain closed while the fetus develops throughout pregnancy, and to open for delivery of the fetus at full term. This dual function is principally attributed to collagen within the extracellular matrix (ECM). However, recent evidence suggests that other ECM, and non-ECM, components play a role as well. One component is smooth muscle cells arranged circumferentially near the internal os. In this study, we investigate correlations between cervical smooth muscle cell force generation and the effective scatterer diameter (ESD), a quantitative ultrasound parameter directly related to the acoustic impedance distribution and, therefore, a potential biomarker of muscle contractility. Using whole cervical slices (N = 5), we determined significant positive correlations (quantified with Pearson's r) between muscle force generation and ESD immediately after administration of oxytocin (median r = 0.90). In summary, the ESD may prove a useful biomarker for studying structure and function of cervical smooth muscle in vivo.

Skeletal Muscle Assessment Using Quantitative Ultrasound: A Narrative Review

“…Santoso et al investigated correlations between cervical smooth muscle force generation and ESD values. They found a significant positive correlation between muscle force generation and ESD immediately after oxytocin administration, suggesting ESD as a useful biomarker for studying cervical muscle contractility, an important factor for proper fetal development and delivery [ 101 ].…”