Objective The aim of this study is to explore the practical value of prenatal magnetic resonance imaging (MRI) in the assessment of congenital cystic lung disease in fetuses, to evaluate the relative size of the lesion and the status of lung development, and to make an attempt at utilizing the strength of MRI in post-processing to obtain assessment indicators of the size of the lesion and the status of lung development, with which predictions can be made for the prognosis that these fetuses may face after birth. We retrospectively collected and analyzed the data of fetuses diagnosed with congenital cystic lung disease. Prenatal ultrasound examination of these fetuses led to the diagnosis that they were suspected of having congenital cystic lung disease and the diagnosis was confirmed by subsequent prenatal MRI. The fetuses were followed up to track their condition at birth (postnatal respiratory distress, mechanical ventilation, etc.), whether the fetuses underwent surgical treatment, and the recovery of the fetuses after surgical treatment. The recovery of the fetuses was followed up to explore the feasibility of prenatal MRI examination to assess fetal congenital pulmonary cystic disease, and to preliminarily explore the predictive value of prenatal MRI for the prognosis of fetuses with congenital pulmonary cystic disease.

Methods MRI fetal images were collected from pregnant women who attended the West China Second University Hospital of Sichuan University between May 2018 and March 2023 and who were diagnosed with fetal congenital pulmonary cystic disease by prenatal ultrasound and subsequent MRI. Fetal MRI images of congenital cystic lung disease were post-processed to obtain the fetal lung lesion volume, the fetal affected lung volume, the healthy lung volume, and the fetal head circumference measurements. The signal intensity of both lungs and livers, the lesion volume/the affected lung volume, the lesion volume/total lung volume, the cystic volume ratio (CVR), and the bilateral lung-liver signal intensity ratio were measured. The feasibility and value of MRI post-processing acquisition indexes for evaluating the prognosis of fetuses with congenital cystic lung disease were further analyzed by combining the follow-up results obtained 6 months after the birth of the fetus. Logistic regression models were used to quantify the differences in maternal age, gestational week at the time of MRI, CVR, and bilateral lung-to-liver signal intensity ratio, and to assess whether these metrics correlate with poor prognosis. Receiver operating characteristic (ROC) curves were used to assess the value of the parameters obtained by MRI calculations alone and in combination with multiple metrics for predicting poor prognosis after birth.

Results We collected a total of 67 cases of fetuses diagnosed with congenital cystic lung disease by fetal MRI between May 2018 and March 2023, and excluded 6 cases with no normal lung tissue in the affected lungs, 11 cases of fetal induction, and 3 cases of loss of pregnancy. In the end, 47 cases of fetuses with congenital cystic lung disease were included, of which 30 cases had a good prognosis and 17 cases had a poor prognosis. The difference in the difference between the signal intensity ratios of the affected and healthy sides of the lungs and livers of the fetuses in the good prognosis group and that in the poor prognosis group was statistically significant (P<0.05), and the signal intensity ratio of the healthy side of the lungs and livers was higher than the signal intensity ratio of the affected side of the lungs and livers. Further analysis showed that CVR (odds ratio OR=1.058, 95% confidence interval CI: 1.014-1.104), and the difference between the lung-to-liver signal intensity ratios of the affected and healthy sides (OR=0.814, 95% CI: 0.700-0.947) were correlated with poor prognosis of birth in fetuses with congenital cystic lung disease. In addition, ROC curve analysis showed that the combined application of lesion volume/affected lung volume and the observed difference in the signal intensity ratio between the affected and healthy lungs and liver predicted the prognosis of children with congenital cystic lung disease more accurately than the single-parameter judgment did, with the area under the curve being 0.988, and the cut-off value being 0.33, which corresponded to a sensitivity of 100%, a specificity of 93.3%, and a 95% CI of 0.966-1.000.

Conclusions Based on the MRI of fetuses with congenital cystic lung disease, we obtained information on lesion volume, lesion volume/affected lung volume, lesion volume/total lung volume, CVR, and bilateral lung-to-liver signal intensity ratio difference, all of which showing some clinical value in predicting the poor prognosis in fetuses with congenital cystic lung disease. Furthermore, among the combined indexes, the lesion volume/affected lung volume and bilateral lung-to-liver signal intensity ratio difference are more effective predictors for the poor prognosis of fetuses with congenital cystic lung disease, and show better efficacy in predicting the poor prognosis of fetuses with congenital cystic lung disease. This provides a new and effective predictive method for further assessment of pulmonary lung development in fetuses with congenital cystic lung disease, and helps improve the assessment and prediction of the prognosis of fetuses with congenital cystic lung disease.