A force‐measuring device combined with ultrasound‐based elastography for assessment of the uterine cervix

Abstract

Introduction In this feasibility study, we hypothesize that the evaluation of cervical biomechanical strength can be improved if cervical length measurement is supplemented with quantitative elastography, which is a technique based on conventional ultrasound elastography combined with a force‐measuring device. Our aims were to: (a) develop a force‐measuring device; (b) introduce a cervical elastography index (CEI) and a cervical strength index (CSI; defined as cervical length × CEI); (c) evaluate how these indexes assess the cervical softening that takes place during normal pregnancy; and (d) how these indexes predict the cervical dilatation time from 4 to 10 cm. Material and methods An electronic force‐measuring device was mounted on the handle of the transvaginal probe, allowing for force measurement when conducting elastography. The study group concerned with normal cervical softening included 44 unselected pregnant women. Outcomes were CEI and CSI at different gestational ages. The study group for labor induction included 26 singleton term pregnant women admitted for labor induction. Outcome was defined as cervical dilatation time from 4 to 10 cm. Elastography measured the changes in mean gray value (intensity) during manual compressions. Region of interest was set within the anterior cervical lip. Results We found that the mean of all variables regarding cervical softening decreased from early to late pregnancy: ie cervical length from 34 to 29 mm, CEI from 0.17 to 0.11 N, and CSI from 5.9 to 3.1 N mm. Moreover, the cervical dilatation time during labor induction was associated with CEI, although not statistically significantly (area under the ROC curve of 0.67), but not with the Bishop score, the cervical length, or the CSI. Conclusions We propose that quantitative elastography based on changes in the intensity of the B‐mode ultrasound recording, in combination with a force‐measuring device on the handle of the vaginal probe, deserves further investigation as an approach for evaluation of cervical biomechanical strength.

Reassessing the Bishop score in clinical practice for induction of labor leading to vaginal delivery and for evaluation of cervix ripening

“…[ 19 , 20 ] Second, addition of multiple markers of cervical morphometry with, by example, elastography holds promise to evaluate critical features of antepartum cervix remodeling. [ 21 ] A third approach, distinct from sonography, is Raman spectroscopy for in vivo interrogation of the ectocervix. [ 22 ] This method can create a unique fingerprint of specific molecules during a routine exam which assesses specific biomolecular structure, concentrations, and water content — factors known to change during cervical remodeling.…”

Advances in the clinical application of ultrasound elastography in uterine imaging

“…Various approaches have been reported in the literature to improve the application of USE in obstetrics. Studies have shown that SE can qualitatively detect the elasticity of the cervix when using reference materials, but the application of this technique in cervical disease has not been studied [ 80 ]. Hamza et al sought to combine lower uterine segment (LUS) thickness and SE to predict successful IOL within 24 h and intervals to onset of labor.…”