Value of MRI findings for the evaluation of a hernia sac in fetuses with congenital diaphragmatic hernia / 中华放射学杂志

ABSTRACT

Objective:To explore the value of MRI signs in assessing the presence or absence of hernia sacs in fetuses with congenital diaphragm hernia.Methods:MRI images of 57 patients with congenital diaphragm hernia confirmed by postpartum surgery were analyzed from November 2016 to December 2020 in Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, with a gestational age of 20－40 (28±5) weeks. In postpartum surgery, 18 cases were found with hernia sacs (hernia sac group) and 39 cases without hernia sacs (hernia-free group). Seven MRI signs were analyzed, including hernia peripheral enveloping sensation, smooth lung-hernia interface, crescent-shaped lung compression, residual lung tissue on the affected side, heart displacement, effusion above the lung-hernia interface and effusion below the lung-hernia interface. The differences in MRI signs between the hernia sac and hernia-free groups were compared using the χ 2 test or Fisher′s exact probability method. The diagnostic efficacy of each sign was calculated. The MRI signs with statistical differences between the two groups were included in the predictive integration model, and 1 point was scored for each sign, the imaging score of each fetus was calculated, and the efficacy of imaging points in diagnosing the presence or absence of hernia sacs was assessed by the subject manipulation receiver operating characteristics (ROC) curve. Results:There were statistically significant differences in 5 MRI signs between the hernia sac and the hernia-free groups, namely hernia peripheral enveloping sensation (χ2=25.74, P<0.001), smooth lung-hernia interface (χ2=48.20, P<0.001), crescent-shaped lung compression (χ2=57.00, P<0.001), residual lung tissue on the affected side (χ2=12.14, P<0.001) and effusion above the lung-hernia interface (χ2=4.31, P=0.022). Among them, the sign of crescent-shaped lung compression had the highest diagnostic efficacy, and the sensitivity, specificity and accuracy all were 100%. Five statistically significant MRI signs were included in the predictive integration model, and the area under the ROC curve was 0.999, the sensitivity was 100%, the specificity was 94.9%, and the optimal threshold was 2 points. Conclusion:Fetal MRI signs and predictive integration model can effectively identify the presence or absence of hernia sacs in fetuses with congenital diaphragm hernia, which has certain clinical significance.