Comparing the Diagnostic Yield of Antenatal Fetal Ultrasound, Neurosonography, and MRI for Detecting CNS Anomalies: A Prospective Study

Abstract

Background: This study is aimed to compare the accuracy of prenatal standard brain ultrasound (US), neurosonography (NSG), and magnetic resonance imaging (MRI) for diagnosing central nervous system (CNS) anomalies.Methods: In this prospective study pregnant women were consecutively recruited in their second or third trimester of pregnancy, who either had a positive history of fetal brain anomalies in previous pregnancies or were pregnant with fetuses suspected to have brain abnormalities on ultrasound exam. Based on standard US, NSG, and MRI findings concordancy fetuses were subdivided into four groups: the MRI/NSG findings confirmed, supplemented, contradicted, or ruled out the initial US diagnosis. NSG/MRI discordancy was also reported separately. Live births were followed for 18 months to assess the course of postnatal neurodevelopment.Results: Generally, 49.3% of fetuses showed concordancy between US and NSG/MRI; among remaining cases, NSG/MRI showed additional findings to US, changes US diagnosis, and demonstrated a normal brain in 73.2%, 23.9%, and 2.8% of cases, respectively. MRI found additional features to NSG in 22.9% of fetuses, most of whom were diagnosed with intracranial hemorrhage or cortical malformation unseen on NSG or showed a more extensive cortical malformation in MRI. Twenty fetuses underwent postnatal brain MRI and all confirmed prenatal MRI findings with 100% concordancy. Cases with postnatal normal neurodevelopment were more likely to show concordancy between US, NSG, and MRI.Conclusions: Prenatal MRI is the most accurate imaging modality for detecting CNS anomalies antenatal and might supplement the US/NSG findings, and sometimes contradicts or excludes the initial US diagnosis.

Keywords

• cns anomalies
• fetal mri
• neurosonography
• prenatal ultrasound