Diagnosis of central nervous system abnormalities: comparison of prenatal neurosonography and foetal magnetic resonance imaging findings

Abstract

Magnetic resonance imagining (MRI) is gradually becoming the more preferred imaging modality in the evaluation of central nervous system (CNS) abnormalities rather than foetal ultrasonography (USG). The aim of this study was to compare the findings of prenatal neurosonography and foetal MRI. The study was a retrospective study analysing the records of 160 pregnant women who underwent both foetal MRI and USG due to suspicion of CNS abnormalities between 2008 and 2019. Indications for applying foetal MRI were neurosonography and foetal MRI findings. When the compatibility between MRI and USG results was examined in CNS abnormalities, it was found fully compatible in 61.3% of cases, partially compatible in 24.53% of cases, and not compatible in 14.5% of cases. When comparing prenatal neurosonography and foetal MRI findings, additional findings were reported in 16.9% of cases, and no additional finding was reported in 66.8% of cases. While normal anatomical findings were reported in 8.8% of the cases in MRI, the diagnosis made by neurosonography changed in 7.5%. Foetal MRI has more advantages than USG both in imaging the CNS abnormalities in more detail and in determining the accompanying additional anomalies. IMPACT STATEMENT What is already known on this subject: USG is a safe, practical and cost-effective primary imaging method that is widely used for foetal anomaly screening. However, there may sometimes be difficulties in evaluating the foetal brain structures due to foetal position which is unsuitable for imaging, extremely obese with a high body mass index, oligohydramnios and ossified foetal skull. For this reason, magnetic resonance imaging (MRI) is used as the most commonly used imaging method after USG in the evaluation of foetal anatomy, especially CNS. What do the results of this study add?: In our study, we saw that foetal MRI has more advantages than neurosonography in both seeing CNS abnormalities in more detail and recognising additional anomalies that may accompany. What are the implications of these findings for clinical practice and/or further research?: We have seen that besides neurosonography, foetal MRI can provide important information that can affect the clinical approach in pregnancy management by increasing the correct diagnosis in pregnancies with congenital CNS abnormalities. MRI: it is the best secondary imaging modality that can aid diagnosis in addition to neurosonography in the diagnosis of CNS abnormalities and in suspected cases. Therefore, foetal MRI should be used more widely in prenatal diagnosis.