EP17.55: Interobserver reproducibility of a novel cervical elastography index

The present study aims to evaluate the interobserver reproducibility of a novel cervical Strain Imaging (elastography) index in pregnant women at 18-24 weeks. Cross-sectional study of cervical elastography (CE) and cervical length (CL) obtained by vaginal ultrasonography that evaluated 100 pregnant women at high and low risk for preterm birth based on prior obstetric history. The elastographic index (EI) suggested by this study was calculated using markers (ROI) positioned at the external os (EOs) and internal os (IOs) of the cervix to obtain the Strain Ratio (SR), a metric tool that determines how many times the IOs is less elastic (hard) compared to the EOs. CL was also performed concomitantly for interobserver reproducibility purposes using the interclass confidence coefficient (ICC) and 95% Bland-Altman limits of agreement. Median values for maternal age, parity and gestational age were 27 years, two previous births and 20 weeks, respectively. 63% were multipara, 28.6% with a prior Caesarean section. 15% were considered at high risk for preterm birth. Mean EI of examiner 1 was 3.56 [standard deviation (SD) 1.80] and of examiner 2 was 3.64 (SD 2.06), with an ICC of 0.935 [95% confidence interval (CI) 0.905 - 0.956]. Mean CL of examiner 1 was 33.4mm (SD 7.26) and of examiner 2 was 32.7mm (SD 7.10), with an ICC of 0.915 [95% CI 0.874 – 0.943]. EI using CE obtained by vaginal ultrasonography has a high interobserver reproducibility. The potential for this new index to improve prediction of preterm birth at mid-gestation still needs to be tested. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.