Role of prenatal magnetic resonance imaging in fetuses with isolated agenesis of corpus callosum in the era of fetal neurosonography: A systematic review and meta-analysis.

Filomena Giulia Sileo,Danilo Buca,Sophie Masmejan,Alice D’Amico,Massimo Caulo,Lucia Manganaro,Emma Bertucci,Asma Khalil,Francesco D’Antonio,Luigi Nappi,Marco Liberati,Daniele Di Mascio,Giuseppe Rizzo,Tim Van Mieghem

doi:10.1111/aogs.13958

Abstract

Corpus callosum agenesis (ACC) is frequently diagnosed during fetal life; its prognosis depends also on additional anomalies. The additional value of fetal magnetic resonance imaging (MRI) in fetuses with "isolated" complete (cACC) and partial (pACC) agenesis of the corpus callosum on ultrasound is still debated. We performed a systematic literature review and meta-analysis including fetuses with a prenatal diagnosis of cACC and pACC without associated structural anomalies on ultrasound, undergoing fetal MRI. The primary outcome was the rate of additional anomalies detected at fetal MRI. Further analyses assessed the effect of type of ultrasound assessment (neurosonography vs standard axial assessment), gestational age at fetal MRI and rate of postnatally detected brain anomalies. Random-effect meta-analyses of proportions were used to analyze the data. Fourteen studies (798 fetuses) were included. In cases with isolated cACC, 10.9% (95% CI 4.1-20.6) and 4.3% (95% CI 1.4-8.8) additional anomalies were detected by fetal MRI and postnatally, respectively. Stratifying according to the type of ultrasound assessment, the rate of associated anomalies detected only on fetal MRI was 5.7% (95% CI 0.5-16.0) with dedicated neurosonography and 18.5% (95% CI 7.8-32.4) with a standard axial assessment. In fetuses with isolated pACC, 13.4% (95% CI 4.0-27.0) and 16.2% (95% CI 5.9-30.3) additional anomalies were detected by fetal MRI or postnatally, respectively. Stratifying according to the type of ultrasound assessment, the rate of associated anomalies detected only on fetal MRI was 11.4% (95% CI 2.7-25.0) when dedicated neurosonography was performed. Cortical and posterior fossa anomalies represented the most common anomalies missed at ultrasound with both cACC and pACC. Due to the very small number of included cases, stratification according to early (<24weeks of gestation) and late (>24weeks) fetal MRI could not be done for either cACC or pACC. The rate of associated anomalies detected exclusively at fetal MRI in isolated ACC undergoing neurosonography is lower than previously reported. Cortical and posterior fossa anomalies are among the most common anomalies detected exclusively at MRI, thus confirming the crucial role of fetal MRI in determining the prognosis of these fetuses. However, some anomalies still go undetected prenatally and this should be stressed during parental counseling.

Highlights

Corpus callosum agenesis (ACC) is frequently diagnosed during fetal life; its prognosis depends on additional anomalies
In fetuses with isolated pACC, 13.4% and 16.2% additional anomalies were detected by fetal magnetic resonance imaging (MRI) or postnatally respectively
Chromosomal anomalies can be found in 5% of children with isolated Agenesis of corpus callosum (ACC),[2] but in up to 18% of fetuses when ACC is associated with other central nervous system (CNS) and extra-CNS anomalies, and are the main determinant of postnatal outcome in children affected by these anomalies. 4-6

Summary

Introduction

Corpus callosum agenesis (ACC) is frequently diagnosed during fetal life; its prognosis depends on additional anomalies. Stratifying according to the type of ultrasound assessment, the rate of associated anomalies detected only on fetal MRI was 5.7% (95% CI 0.5-16.0) with dedicated neurosonography and 18.5% (95% CI 7.832.4) with a standard axial assessment. Stratifying according to the type of ultrasound assessment, the rate of associated anomalies detected only on fetal MRI was 11.4% (95% CI 2.7-25-0) when dedicated neurosonography was performed. The corpus callosum is the largest commissure in the central nervous system (CNS) with a cardinal role in the execution of physical, cognitive and affective functions.[1,2,3,4] Developmental defects of the corpus callosum, including either complete (cACC) or partial (pACC) agenesis, hypoplasia or dysplasia are among the most common CNS anomalies diagnosed during fetal life. Prenatal diagnosis of pACC is much more challenging and many of the indirect signs found in fetuses with cACC may be missing

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