胎儿脑中线弯曲的产前诊断及妊娠结局分析

Study on prenatal diagnosis and pregnancy outcome of cases with distortion of the interhemispheric fissure of fetus

目的分析胎儿脑中线弯曲的超声和磁共振成像(MRI)表现及妊娠结局,探讨胎儿脑中线弯曲对严重神经系统异常的提示价值。方法选取2018年3月至2023年4月于首都医科大学附属北京妇产医院产前常规超声检查发现胎儿脑中线弯曲的孕妇,分析其超声和MRI影像学资料、遗传学检查结果及妊娠结局。结果12例为胎儿脑中线整体弯曲,6例为胎儿脑中线局部弯曲。整体弯曲的12例中11例为颅内多发异常,主要异常包括2例半侧巨脑畸形、3例脑皮质发育异常、3例双侧脑室重度增宽、2例单侧脑室重度增宽、1例疑似颅内出血及1例颅板下蛛网膜囊肿,其中1例合并颅外异常即法洛四联症。6例脑中线局部弯曲的病例中,5例诊断为脑皮质发育异常,1例诊断为颅内占位;5例脑皮质发育异常的病例中3例通过产前超声诊断,余2例通过MRI诊断;6例胎儿均未发现合并其他系统异常。脑中线整体弯曲的病例中4例进行遗传学检查,核型均未见异常。脑中线局部弯曲的病例中3例进行遗传学检查,包括1例核型及拷贝数变异(CNV)未见异常;1例CNV未见异常;1列核型及CNV未见异常,而全外显子检测显示TUBB3基因新发突变。12例脑中线整体弯曲的病例中8例选择终止妊娠,2例失访,2例继续妊娠并分娩,其中1例患儿在11月龄时行法洛四联症矫正手术时死亡,另1例患儿出生后行颅内囊肿分流术,术后新生儿生长发育正常。而6例脑中线局部弯曲的病例均选择终止妊娠。结论脑中线弯曲通常合并严重的颅内异常,与不良妊娠结局相关。脑中线局部弯曲是提示脑皮质发育异常的重要超声指标。产前如发现脑中线弯曲,必须进行胎儿神经学超声及头颅MRI检查以明确诊断,并尽量完善遗传学检查。

Objective To investigate prenatal diagnosis and pregnancy outcome of cases with distortion of the interhemispheric fissure of fetus.Method Retrospectively analyzed prenatal ultrasound and MRI manifestations,genetic examinations and pregnancy outcome of 18 cases,in which distortion of the interhemispheric fissure was found on routine ultrasound scanning in Beijing Obstetrics and Gynecology Hospital during March 2018 and April 2023.Result 12 cases were total distortion of the interhemispheric fissure and 6 cases were partial one.Cases in total distortion group,multiple intracranial anomalies were detected.Major anomalies were 2 cases of hemimegalencephaly,3 cases of cortical malformation,3 cases of bilateral severe ventriculomegaly,2 cases of unilateral severe ventriculomegaly,1 case of suspicious intracranial hemorrhage,1 case of arachnoid cyst.1 case was complicated with extracranial anomaly,Fallot tetralogy.In partial distortion group,5 cases were diagnosed as cortical malformation,and 1 case was intracranial tumor.Three out of 5 cortical malformation cases were diagnosed by ultrasound,whereas remaining 2 cases were diagnosed by MRI.All 6 cases were not complicated by anomalies in other systems.Genetic examinations were performed in 4/12 cases in total distortion group and showed normal karyotyping;in partial distortion group,genetic examinations were carried out in 3 cases,including normal karyotyping and CNV in 1 case;normal CNV in 1 case;normal karyotyping and CNV,but WES showing de novo mutation of TUBB3 gene.In total distortion group,8 cases chose termination of pregnancy(TOP).2 cases were lost in follow up,whereas 2 cases continued pregnancy till term and delivered.In one case neonate did not survive the surgery for Fallot tetralogy at age of 11 months,and the other case with bilateral hydrocephaly received intracranial cyst shunting after birth for relief pressure on foramen Monroe,and achieved normal neuromotor development.All of 6 cases in partial distortion group underwent TOP.Conclusion Distortion of interhemispheric fissure was complicated with severe intracranial anomalies,implicating negative pregnancy outcome,partial distortion of interhemispheric fissure is a valuable sonographic marker indicating fetal cortical malformation.Detection of distortion sign should prompt further neurosonography,MRI and genetic examinations for definite diagnosis and optimal prenatal management.