Ruolo della risonanza magnetica prenatale in feti con ventricolomegalia isolata nell'era della neurosonografia: uno studio multicentrico

Objectives: To assess the role of fetal magnetic resonance imaging (MRI) in detecting associated anomalies in fetuses presenting with mild and moderate isolated ventriculomegaly (VM) undergoing multiplanar ultrasound (US) evaluation of fetal brain. Methods: Multicenter, retrospective, cohort study involving 15 referral fetal medicine centers in Italy, United Kingdom, and Spain. Inclusion criteria: fetuses affected by isolated VM on US, undergoing detailed assessment of fetal brain via a multiplanar approach. Primary outcome: to report the rate of additional CNS anomalies detected exclusively at prenatal MRI and missed at US; secondary aim: to estimate the incidence of additional anomalies detected exclusively after birth and missed at prenatal imaging. Results: 556 fetuses with a prenatal diagnosis of isolated fetal VM on US were included. Additional structural anomalies were detected at prenatal MRI and missed at US in 5.4% (95% CI 3.8-7.6) of cases. Fetuses with an associated anomaly detected only at MRI were more likely to have moderate compared to mild VM (60.0% vs 17.7%, p<0.001), while there was no significant difference between the proportion of cases with bilateral VM between the two groups (p=0.2). The results of the logistic regression analysis showed that maternal body mass index (OR: 0.85, 95% CI 0.7-0.99, p= 0.030), presence of moderate VM (OR: 5.8, 95% CI 2.6-13.4, p<0.001) and gestational age at MRI ≥24 weeks of gestation (OR: 4.1, 95% CI 1.1-15.3, p= 0.038) were independently associated with the probability of detecting associated anomalies at MRI. Associated anomalies were detected exclusively at birth and missed at prenatal imaging in 3.8% of cases. Conclusions: The rate of associated fetal anomalies missed at US and detected only at fetal MRI in fetuses with isolated mild and moderate VM undergoing neurosonography is lower than that previously reported. The large majority of these anomalies are difficult to detect on ultrasound