VP25.24: Fetal ultrasound, MR imaging and MR autopsy in Cri du chat syndrome: two case reports and review of the literature

Abstract

To assess the role of fetal magnetic resonance imaging (MRI) in detecting associated anomalies in fetuses presenting with isolated severe ventriculomegaly (VM) undergoing multiplanar ultrasound (US) evaluation of fetal brain. Methods: Multicentre, retrospective, cohort study involving eight referral fetal medicine centres in Italy, United Kingdom and Spain. Inclusion criteria were fetuses affected by isolated severe (>15mm) VM on US, defined as VM with normal karyotype and no other additional CNS and extra-CNS anomalies on US, undergoing detailed assessment of fetal brain via a multiplanar approach as suggested by ISUOG guidelines on fetal neurosonogram. The primary outcome of the study was to report the rate of additional CNS anomalies detected exclusively at prenatal MRI and missed at US. Results: 43 fetuses with a prenatal diagnosis of isolated severe VM on US were included in the analysis. Additional structural anomalies were detected at prenatal MRI and missed at US in 23.3% (95% CI 13.1-37.8) of cases. When considering the type of anomalies, midline (mostly hypoplasia of the corpus callosum) and cortical anomalies were both detected only on MRI in 40.0% of fetuses, while supratentorial intracranial hemorrhage was detected on MRI in 20.0% of fetuses, and polymicrogyria and periventricular heterotopia in 10.0%. The results of the logistic regression analysis showed that bilateral rather than unilateral severe VM (OR: 4.3, 95% CI 3.7-5.2, p < 0.001) and the degree of ventricular dilatation (OR: 1.5, 95% CI 1.2-1.5, p < 0.001 each mm of dilatation) were indipendently associated with the probability of detecting associated anomalies only at MRI. Conclusions: Although the rate of associated fetal anomalies missed at neurosonography and detected only at fetal MRI in fetuses with isolated severe VM is lower than that previously reported, the findings from this study support the practice of MRI assessment in every fetus with a prenatal diagnosis of severe VM.