Could magnetic resonance imaging contribute to detecting isolated fetal ventriculomegaly other than additional abnormalities?

Objective: To assess the role of brain magnetic resonance imaging (MRI) in fetuses presenting with isolated ventriculomegaly (IVM) in the ultrasound (US) evaluation of the fetal brain. Methods: US and MRI findings of 197 fetuses diagnosed with IVM between November 2018 and November 2020 were retrospectively evaluated. Fetuses with abnormal karyotypes, additional anomalies, or known etiologies for ventriculomegaly were excluded. US and MRI findings were compared both in terms of mean ventricular measurements and IVM grade. Results: MRI measurements were significantly higher in mild IMV (10.33 +/- 0.38 mm vs. 11.11 +/- 0.51 mm, p< 0.001) compared to US. In mild IVM, MRI measured ventricles larger than US with a mean difference of 0.78 mm. There was no significant difference in US and MRI measurements in terms of mean values in moderate and severe IVM. There was good agreement between US and MRI in detecting right, left and mean IVM severity (Kappa=0.265, Kappa=0.324, and Kappa=0.261, respectively). Linear regression analyses revealed a statistically significant relationship between US and MRI measurements of the right, left, and mean IVM (p<0.001, p<0.001, and p<0.001, respectively). MRI showed perfect agreement with US in detecting IVM laterality (Kappa=1.0, p<0.001). Conclusions: In fetuses with mild IVM detected by US, fetal brain MRI evaluation should be considered for accurate diagnosis. This approach may provide effective strategies in the antenatal management and counseling of these pregnancies.