Reproducibility of Cervical Strain Elastography Using a Standardized Acquisition Protocol in Mid‐Trimester Pregnancy

Abstract

ABSTRACT Objective To evaluate the intra‐and interobserver reproducibility of the cervical elastography index (EI) measurements using strain elastography (SE) with a standardized acquisition protocol. Methods In this prospective cross‐sectional study, 301 women between 18 and 24 weeks of gestation underwent transvaginal ultrasound examination (TVUS). Cervical length (CL) and EI were measured using a defined region of interest (ROI) protocol positioned at the internal and external cervical os, maintaining a 5 mm standardized probe‐to‐cervix distance. Measurements were performed twice by Examiner 1 and once by Examiner 2. Reproducibility was assessed using the intraclass correlation coefficients (ICC) and Bland–Altman analysis. Results Intraobserver reproducibility was high for CL (ICC = 0.984) and EI (ICC = 0.991). Interobserver reproducibility was high for CL (ICC = 0.903) and high for EI (ICC = 0.910 and 0.906). Bland–Altman analysis demonstrated minimal bias and narrow limits of agreement for both measurements. Conclusion Using a standardized acquisition protocol, strain elastography‐derived EI demonstrates high intraobserver and interobserver reproducibility comparable to CL measurement. These findings support its potential clinical applicability in mid‐trimester cervical assessment.