| Objective: This study was aimed to investigate the fetal tracheal morphological characteristics of heterotaxy syndrome,as well as the relationship between bronchial and ipsilateral pulmonary artery position within different heterogeneous types by ultrasound.It was also to evaluate the value of the relationship of bronchus and ipsilateral pulmonary artery in prenatal diagnosis of heterotaxy syndrome(HS).Methods: Patients were divided into three groups: 6 LAI patients,14 RAI patients,and 15 control subjects.Echocardiography was performed on 35 fetuses.The location of abdominal tissues and organs were observed.Tracheal morphology was observed on tracheal coronal section.The tracheal diameter(DT),left bronchial diameter(DLB),right bronchial diameter(DRB).The angles between the lateral edge of the left,right bronchus and the trachea(α,β),as well as the angle between the left and right bronchial medial edges(δ),were recorded.The position correction between fetal bronchus and the ipsilateral pulmonary artery was observed.Results:1.There was no statistically significant difference among the three groups.2.Compared with LAI patients,the incidence of right ventricular outflow tract obstruction,right aortic arch,functional single ventricle,and the absence of arteria lienalis were significantly increased in the RAI patients(P<0.05).In addition,the incidence of APVC was significantly increased(P<0.01).3.Compared with control group,the mean values of fetal DT(P<0.05)and DLB(P<0.01)decreased,while the mean α increased and the mean δ decreased(P<0.01).These differences were statistically significant.The mean values of DLB/DT and DRB/DT in the RAI group increased(P<0.01).The mean β decreased(P<0.01)and the mean value of δ increased(P<0.05).4.In LAI patients,66.7% of them were bilateral hyparterial bronchus and 33.3% were normal positional.Among RAI patients,the subtypes were as below: 64.3% with bilateral eparterial bronchus,7.1% with normal positional,7.1% with mirrored inverse,21.4 % with unknown.There was a significant difference in the relations between the fetal bronchus and ipsilateral pulmonary artery(P<0.05).The relations between the bronchus and the ipsilateral pulmonary artery strongly correlated with the heterogeneous types(correlation coefficient value 0.68).5.Four fetuses were examined at autopsy,including 1 LAI patient and 3 RAI patients.All autopsy fetal heterogeneity types,intracardiac malformations,and extracardiac malformations were consistent with prenatal ultrasound diagnosis.Conclusions:Prenatal ultrasound can clearly show tracheal structure,morphological features and the relationship between bronchus and ipsilateral pulmonary artery on the tracheal coronal section.These results provide a new tool for prenatal diagnosis of HS. |
