探讨神经学超声在产前诊断胼胝体异常中的临床价值。

2021年1月至2022年12月产前超声筛查疑诊胎儿颅脑异常转诊至南京大学医学院附属鼓楼医院妇产医学中心接受神经学超声检查的胎儿97例（妊娠18~40周），对其中20例发现胼胝体异常胎儿的超声筛查、神经学超声、磁共振成像（MRI）验证结果、遗传学检查和产后随访等临床资料进行分析。对20例胎儿胼胝体异常（胚胎发育停滞期影像表现）进行超声分型：胼胝体完全缺失（CACC）、胼胝体部分缺失（PACC）和胼胝体发育不良（DCC）。以MRI诊断结果为准，评价超声诊断与MRI诊断的一致性。

20例颅脑异常胎儿（单胎18例，双胎1例）MRI诊断胼胝体异常20例，合并其他颅脑畸形18例，其中CACC 9例（合并其他颅脑畸形9例）；PACC 7例（合并其他颅脑畸形5例）；DCC 4例（合并其他颅脑畸形4例）。超声筛查诊断胼胝体异常3例，与MRI诊断结果一致的符合率为15%（3/20），其中CACC 2例（均合并其他颅脑畸形，11%，2/18）、PACC 1例。神经学超声诊断胎儿胼胝体异常20例（合并颅脑畸形18例），其中诊断CACC 9例（合并其他预脑畸形9例）；PACC 9例（合并其他颅脑畸形7例）；DCC 2例（合并其他颅脑畸形2例）。神经学超声诊断胼胝体异常的结果与MRI诊断结果一致的符合率为90%（18/20），其中2例将DCC误判为PACC，与MRI诊断结果不一致。神经学超声诊断合并其他颅脑畸形的结果与MRI诊断结果一致的符合率为61%（11/18）。20例胎儿中15例（75%）接受染色体微阵列分析，其中1例出现致病性变异，1例为临床意义不明确变异，余13例胎儿中1例接受全外显子组测序，结果疑似致病变异。临床随访：产前检查后终止妊娠者17例，3例活产，活产儿出生后头颅MRI检查与产前MRI胼胝体异常影像表现一致，1例出生后1年出现左手抽搐，握力差，现复健1年有好转，余2例目前神经发育未见异常。

胎儿神经学超声检查可直观显示胼胝体的形态结构，为临床诊断胼胝体异常及其分型提供准确影像学证据。

To evaluate the clinical value of neurosonography in prenatal diagnosis of abnormalities of the corpus callosum.

From January 2021 to December 2022, the data of 97 fetuses who were suspected to have fetal brain abnormalities by prenatal ultrasound screening during 18-40 weeks of gestation and transferred to the Obstetrics and Gynecology Medical Center of Nanjing Drum Tower Hospital Affiliated to Nanjing University Medical School were analyzed. The clinical data of 20 fetuses with corpus callosum malformations were analyzed, including ultrasonic screening, neurosonography screening, magnetic resonance imaging (MRI), genetic examination, and postpartum follow-up. Twenty cases of fetal corpus callosum abnormalities were classified into three types: complete agenesis of the corpus callusom (CACC), partial agenesis of the corpus callusom (PACC), and dysgenesis of the corpus callosum (DCC). The consistency of ultrasound diagnosis with MRI diagnosis was evaluated.

Among the 20 fetuses with brain abnormalities (18 singleton and two twins), MRI showed that 20 had corpus callosum abnormalities and 18 had other brain malformations, including 9 cases of CACC (all with other brain malformations), 7 cases of PACC (5 combined with other brain malformations), and 4 cases of DCC (all combined with other brain malformations). There were 3 cases of corpus callosum abnormalities detected by ultrasound screening, and the coincidence rate with MRI diagnosis was 15% (3/20); there were 2 cases of CACC (both combined with other brain malformations, 2/18 [11%]) and 1 case of PACC. Twenty cases (18 cases combined with brain malformations) of fetal corpus callosum abnormalities were diagnosed by neurosonography. Nine cases were diagnosed as CACC (9 cases combined with other brain malformations); 9 cases of PACC (7 cases combined with other brain malformations); 2 cases of DCC (2 with other brain malformations). The coincidence rate with MRI diagnosis was 90% (18/20) in fetal corpus callosum abnormalities and 61% (11/18) in corpus callosum abnormalities with other brain malformations. DCC was misdiagnosed as PACC in 2 cases. Of the 20 fetuses with corpus callosum abnormalities, 15 (75%) underwent chromosomal microarray analysis, of which one was found to have pathogenic variants, one was found to have variants of uncertain significance, and one of the remaining 13 fetuses underwent whole exome sequencing, which was suspected to have pathogenic variants. During clinical follow-up, 17 cases were terminated after prenatal examination, and 3 cases were born alive; the postnatal brain MRI findings were consistent with prenatal MRI abnormalities of the corpus callosum. One case had left hand convulsion and poor grip strength 1 year after birth, and improved after 1 year of rehabilitation, and the remaining 2 cases had no abnormal mental development.

Fetal neurosonography can display the morphological structure of the corpus callosum visually, and provide accurate imaging evidence for clinical diagnosis and classification of corpus callosum malformations.