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.

Reproducibility of Liver-to-Thorax Area Ratio Ultrasound Measurements in Congenital Diaphragmatic Hernia.

OBJECTIVES: The aim of this study was to investigate the reproducibility of a standardized method to assess the ultrasound liver-to-thoracic area ratio in fetuses with congenital diaphragmatic hernia. METHODS: We selected 24 images of 9 fetuses diagnosed with left-sided at our institution between January 2010 and December 2017. Eight operators (1 maternal-fetal medicine specialist and 7 sonographers) reviewed the selected images and assessed the ultrasound liver-to-thoracic area ratio according to a standardized protocol. We evaluated the correlation between operators using the intraclass correlation coefficient and compared agreement between the sonographers and a physician with experience in measuring the ultrasound liver-to-thoracic area ratio using a Bland-Altman analysis. RESULTS: Good intraoperator reproducibility was observed for the standardized ultrasound liver-to-thoracic area ratio (intraclass correlation coefficient, 0.78). Good agreement among sonographers and the physician was also observed for the standardized measurements (bias, 0.01; precision, 0.03; limits of agreement, -0.05 to + 0.07). CONCLUSIONS: We demonstrated that good intraoperator and interoperator reproducibility of ultrasound liver-to-thoracic area ratio assessment is feasible after standardizing the method in our center.

Reproducibility of Lung-to-Head Ratio Ultrasound Measurements in Congenital Diaphragmatic Hernia.

OBJECTIVES: This study investigated the reproducibility of standardization of lung-to-head ratio measurements in congenital diaphragmatic hernia (CDH) at our center among sonographers after we standardized the method. METHODS: We reviewed ultrasound images of 12 fetuses with CDH at Mayo Clinic from 2010 to 2016. Nine operators (1 maternal-fetal medicine specialist with experience in measuring the lung-to-head ratio and 8 sonographers), who were blinded to previous findings, reviewed 33 selected images from 12 fetuses with left CDH. The method for lung-to-head ratio measurement was standardized before starting the measurements. The lung-to-head ratio was assessed by different methods to obtain the lung areas: anteroposterior, longest, and area tracing. We evaluated the correlation between operators using the intraclass correlation coefficient (ICC). We also compared agreement between the sonographers and a physician with experience in measuring the lung-to-head ratio using a Bland-Altman analysis. RESULTS: The methods with the best interoperator reproducibility were the standardized anteroposterior lung-to-head ratio (ICC, 0.69) and the standardized lung-to-head ratio tracing (ICC, 0.65) compared to the longest lung-to-head ratio (ICC, 0.56). The standardized lung-to-head ratio tracing had the best agreement among sonographers and the physician (bias, 0.11; limits of agreement, -0.27 to +0.49) than the anteroposterior lung-to-head ratio (bias, 0.35; limits of agreement, -0.13 to + 0.83) and the longest lung-to-head ratio (bias, 0.27; limits of agreement, -0.35 to +0.89). CONCLUSIONS: We demonstrated that the lung-to-head ratio tracing method has high interoperator reproducibility and the best agreement among the operators at our center. Further multicenter studies are necessary to confirm our results.