Standardization and reproducibility of sonographic stomach position grades in fetuses with congenital diaphragmatic hernia

Objectives: The purpose of this study was to evaluate the reproducibility of stomach position grading in congenital diaphragmatic hernia (CDH) as proposed by Cordier et al and Basta et al after standardization of the methods at our center. Methods: We collected sonographic images from 23 fetuses with left-sided CDH at our center from 2010 to 2018. Nine operators (one maternal fetal medicine expert and eight sonographers) reviewed the selected images and graded the stomach position according to the methods of Cordier et al and Basta et al. We assessed the interoperator agreement with Fleiss's kappa statistics. Results: Overall agreement amongst all operators was moderate for both methods proposed by Cordier et al (k = 0.60, SE 0.07, 95% CI 0.47-0.73, P '.0001) and Basta et al (k = 0.60, SE 0.06, 95% CI 0.47-0.73, P '.0001). Interoperator agreement was moderate for grade 3 with the method by Cordier et al (k = 0.45, SE 0.09, 95% CI 0.27-0.64, P '.0001) and fair for grade 4 with the method by Basta et al (k = 0.33, SE 0.08, 95% CI 0.18-0.49 P '.0001). Conclusions: Our study demonstrates a fair to moderate interoperator agreement of the stomach position grading methods proposed in the literature after standardization of the methods at our center. Further multicenter studies are needed to confirm our results.