Standardization of measurement of cervical elastography, its reproducibility, and analysis of baseline clinical factors affecting elastographic parameters

Abstract

Objective To provide a standardized protocol for the measurement of cervical strain elastography, present its reproducibility, and analyze baseline clinical factors affecting the measurement of elastographic parameters. Methods This study was performed by the Korean Research Group of Cervical Elastography. We enrolled pregnant women according to our study protocol. After measuring the cervical length, elastography was performed using the E-Cervix ™ quantification tool to measure the strain of the cervix using intrinsic compression. We evaluated 5 elastographic parameters, namely, the strain of the internal os of the cervix (IOS), strain of the external os of the cervix (EOS), ratio of the strain of IOS and EOS, elasticity contrast index, and hardness ratio. For baseline clinical factors, we examined the maternal body mass index, blood pressure, heart rate, uterine artery Doppler indices, and fetal presentation. Results We established a specific protocol for the measurement of cervical elastography using the E cervix program. For all elastographic parameters, the intra-observer intraclass correlation coefficient (ICC) ranged from 0.633 to 0.723 for single measures and from 0.838 to 0.887 for average measures, and the inter-observer ICC ranged from 0.814 to 0.977 for single measures and from 0.901 to 0.988 for average measures. Regression analysis showed that the measurement of the elastographic parameter was not affected by baseline clinical factors. Conclusion We present a standardized protocol for the measurement of cervical elastography using intrinsic compression. According to this protocol, reproducibility was acceptable and the measurement of elastographic parameters was not affected by the baseline clinical factors studied.

Sonoelastographic Assessment of the Uterine Cervix in the Prediction of Imminent Delivery in Singleton Nulliparous Women Near Term

“…Increased strain reflects increased deformation and softer tissue, whereas decreased strain reflects reduced deformation and stiffer tissue. Strain elastography is dependent on the compression exerted on the cervix and is subjected to substantial interobserver and intraobserver variability 16–19 . To overcome these limitations, new imaging tools have been developed, trying to overcome these limitations.…”

Uterine Cervical Change at Term Examined Using Ultrasound Elastography: A Longitudinal Study

“…Reproducibility should also be taken into consideration. We previously reported reproducibility in terms of intra- and inter-observer intraclass correlation coefficient (ICC), which ranged between 0.838 and 0.887 for intra-observer ICC and between 0.901 and 0.988 for inter-observer ICC [ 17 ]. Although the results showed good to excellent reproducibility, it would be reasonable, and customary to present mean or median values from multiple measurements.…”

“…The median values of the three measurements were used for the analysis. The cervical length measurement and E-Cervix elastography were performed according to previously described protocol [ 17 ]. E-Cervix uses in vivo compression by internally generating fine vibration through organ motion, such as adjacent arterial pulsation and breathing without manual compression.…”

“…As it uses internal compression, E-Cervix elastography is less operator-dependent than other ultrasound elastography machines that employ external compression. We have reported its reproducibility and utility in predicting preterm delivery in pregnancies with a moderately short cervix [ 15 , 16 , 17 ]. We found that there were changes in E-Cervix parameters antedating preterm delivery.…”

Obstetric ultrasound: where are we and where are we going?

“…In strain elastography a mechanical force is manually applied to cause the displacement of tissues and in shear wave elastography an acoustic force creates a mechanical impulse that induces displacement of tissues in the form of shear-waves [ 95 ]. The usefulness in obstetrics has been investigated for the cervix [ 96 ], specifically to attempt and predict preterm labor [ 97 ], and the placenta [ 98 ] and in abnormal placental invasion to differentiate between placenta accreta spectrum (formerly known as morbidly adherent placenta) [ 99 ].…”