The Diagnostic Value Of Prenatal MRI In Congenital Diaphragmatic Hernia

ObjectiveAnalysis and summary of the characteristics of magnetic resonance imaging(MRI)of fetal congenital diaphragmatic hernia(CDH).To explore the value of prenatal MRI in displaying the anatomical structure and imaging diagnosis of fetal CDH.Materials and MethodsPatients:This study was approved by the institute’s ethics committee.A total of 19 pregnant women(age:23-39 years old,mean age:31.1±5.2 years old,median age:32 years old)who were suspected of CDH by routine prenatal ultrasound examination from January 2018 to December 2019 were recruited in this study.Gestational week:23-37 weeks,mean gestational week:30.1±4.5 weeks,median gestational week:30 weeks).MRI examination:The MRI examinations were performed on 1.5T MRI scanner(MAGNETOM Sonata,Siemens,Germany).The scan sequence included:Half-Fourier acquisition single-shot turbo spin-echo(HASTE),true fast imaging with steady-state precession(true-FISP),T1-weighted imaging(T1W1),StarVIBE(stars volumetric interpolated breath-hold examination)sequence and diffusion weighted imaging(DWI).Axial,coronal and sagittal scans were performed in HASTE.True-FISP and T1WI.StarVIBE was used instead of T1WI when breath holding was poor and axial or sagittal scans were performed on DWI.Image analysis:The MRI features of gastric hernia,intestinal hernia,hepatic hernia,renal hernia,splenic hernia,pulmonary dysplasia and "hourglass sign" were included in the analysis,among which "hourglass sign" was first used as the MRI sign of CDH in the study.Two radiologists used double-blind method to independently analyze the fetal images in each case and evaluate the presence or absence of each sign.Two lungs were reconstructed by using a 3D Slicer to calculate the percent predicted lung volumes(PPLV).Statistical analysis:Measurement data were expressed as x±s,and counting data were expressed as frequency.Kappa consistency test was used to calculate the consistency between the two radiologists.Fisher exact probability method was used to compare the difference of signs between groups,and independent two-sample t-test was used to compare the difference of PPLV with different prognosis.P<0.05 was considered statistically significant.ResultsPrenatal sonography of 19 fetuses shows 14 cases of left diaphragmatic hernia and 5 cases of right diaphragmatic hernia.Magnetic resonance imaging showed hernia organs including the stomach,intestines,liver,kidneys and spleen.There were 12 cases(1 2/19,63.16%)with gastric hernia,13 cases(11/19,68.42%)with intestinal hernia,5 cases(5/19,26.32%)with hepatic left lobe hernia,5 cases(5/19,26.32%)with hepatic right lobe hernia,3 cases(3/19,15.79%)with renal hernia,and 3 cases(3/19,15.79%)with splenic hernia.The incidence of gastric hernia in left diaphragmatic hernia was higher than that in right diaphragmatic hernia(P=0.038<0.05).The incidence of hepatic hernia of right diaphragmatic hernia was higher than that of left diaphragmatic hernia(P=0.022<0.05).There was no statistically significant difference in the incidence of other signs of intestinal hernia,renal hernia,and splenic hernia between left and right diaphragmatic hernia(P values were 0.397,0.624,and 0.376,respectively).There were 11 cases of 19 CDH fetuses with"hourglass sign",including 7 cases of left diaphragmatic hernia(7/14,50%)and 4 cases of right diaphragmatic hernia(4/5,80%).The overall diagnostic sensitivity of"hourglass sign" to CDH was 57.89%,and there was no statistically significant difference in the positive rate of left and right diaphragmatic hernia(P=0.267>0.05).The results of CDH image interpretation by 2 radiologists were consistent(Kappa value range:0.798-0.923).Follow-up survey:8 cases survived after birth and surgical treatment,6 cases were induced labor,1 case was lost to follow-up and 4 cases died within 2 days after birth.The mean PPLV of postpartum survivors was(0.44±0.16)× 100%,the mean PPLV of postpartum deaths was(0.08±0.04)× 100%,and the mean PPLV of induced labor cases was(0.52±0.31)×100%.The difference of PPLV between postpartum survival and stillbirth was statistically significant(P<0.05).ConclusionAnatomical site of diaphragmatic hernia is one of the important factors impact assessments of prenatal and postnatal treatment,prenatal MRI assessment of CDH anatomical site helps to provide a more appropriate prenatal counseling and duly incorporated in the perinatal management.MRI can be clearly display and differentiate the contents of CDH into the chest cavity,especially to the intestines and liver showed more advantages on display.MRI can be used for further examination of patients with unsatisfactory chest ultrasound and unclear diagnosis.