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

Abstract

Introduction 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. Material and methods 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. Results 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 (<24 weeks of gestation) and late (>24 weeks) fetal MRI could not be done for either cACC or pACC. Conclusions 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.

Role of prenatal magnetic resonance imaging in fetuses with isolated anomalies of corpus callosum: multinational study

“…In a recent systematic review, we reported that, among fetuses with isolated agenesis of the CC (ACC), the rate of associated anomalies detected exclusively on fetal MRI was lower when neurosonography was performed (5.7%), when compared with the basic assessment of fetal brain (18.5%) 13 . However, the small sample size of the included studies and the heterogeneity of gestational age (GA) at ultrasound and MRI assessments, type and time of follow-up make the results of this systematic review difficult to generalize.…”

Prenatal Magnetic Resonance Imaging in the Diagnosis of Malformation Forebrain

“…По данным ряда авторов, применение МРТ позволяет повысить эффективность пренатальной диагностики среди всех аномалий головного мозга плода на 16% [8] и определиться с прогнозом в 20% уже диагностированных случаев [9]. Кортикальные мальформации и аномалии задней черепной ямки являются одними из наиболее распространенных пороков, которые диагностируются по данным пренатальной МРТ, что подтверждает решающую роль метода в определении прогноза в указанных случаях [10]. В нашем исследовании применение пренатальной МРТ при оценке аномалий развития конечного мозга в 9,5% (2/21) случаев позволило получить дополнительные данные, у 14,3% (…”

Moving beyond the diatribe on ultrasound vs MRI

“…A thorough multiplanar ultrasound assessment of the fetal brain according to International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) guidelines 2 is paramount either in cases of an isolated anomaly [3][4][5] or in fetuses at high risk of brain injury, as described by van der Knoop et al 1 . However, there are a few issues that we believe should always be taken into account when discussing the role of neurosonography and fetal MRI in fetuses at risk for brain abnormalities.…”

“…A thorough multiplanar ultrasound assessment of the fetal brain according to International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) guidelines 2 is paramount either in cases of an isolated anomaly 3–5 or in fetuses at high risk of brain injury, as described by van der Knoop et al 1 …”