Role of fetal magnetic resonance imaging in fetuses with congenital cytomegalovirus infection: multicenter study

Objective: To investigate the role of fetal brain magnetic resonance imaging (MRI) in detecting associated anomalies in fetuses with congenital cytomegalovirus (CMV) infection and normal neurosonography. Methods: This was a multicenter, retrospective cohort study of patients examined between 2012 and 2021 in 11 referral fetal medicine centers in Italy. Inclusion criteria were fetuses with congenital CMV infection diagnosed by polymerase chain reaction analysis of amniotic fluid, pregnancies that underwent detailed multiplanar ultrasound assessment of the fetal brain as recommended by the International Society of Ultrasound in Obstetrics and Gynecology, maternal age ≥ 18 years, normal fetal karyotype and MRI performed within 3 weeks after the last ultrasound examination. The primary outcome was the rate of central nervous system (CNS) anomalies detected exclusively on MRI and confirmed after birth or autopsy in fetuses with a prenatal diagnosis of congenital CMV infection and normal neurosonography at diagnosis. Additional CNS anomalies were classified into anomalies of the ventricular and the periventricular zone, intracranial calcifications in the basal ganglia or germinal matrix, destructive encephalopathy in the white matter, malformations of cortical development, midline anomalies, posterior fossa anomalies and complex brain anomalies. We evaluated the relationship between the incidence of structural CNS malformations diagnosed exclusively on fetal MRI and a number of maternal and gestational characteristics. Univariate and multivariate logistic regression analyses were used to identify and adjust for potential independent predictors of the MRI diagnosis of fetal anomalies. Results: The analysis included 95 fetuses with a prenatal diagnosis of congenital CMV infection and normal neurosonography referred for prenatal MRI. The rate of structural anomalies detected exclusively at fetal MRI was 10.5% (10/95). When considering the type of anomaly, malformations of cortical development were detected on MRI in 40.0% (4/10) of fetuses, destructive encephalopathy in 20.0% (2/10), intracranial calcifications in the germinal matrix in 10.0% (1/10) and complex CNS anomalies in 30.0% (3/10). On multivariate logistic regression analysis, only CMV viral load in the amniotic fluid, expressed as a continuous variable (odds ratio (OR), 1.16 (95% CI, 1.02-1.21); P = 0.02) or categorical variable (> 100 000 copies/mL) (OR, 12.0 (95% CI, 1.2-124.7); P = 0.04), was independently associated with the likelihood of detecting fetal anomalies on MRI. Associated anomalies were detected exclusively at birth and missed by both prenatal neurosonography and fetal MRI in 3.8% (3/80) of fetuses with congenital CMV infection. Conclusions: Fetal brain MRI can detect additional anomalies in a significant proportion of fetuses with congenital CMV infection and negative neurosonography. Viral load in the amniotic fluid was an independent predictor of the risk of associated anomalies in these fetuses. The findings of this study support a longitudinal evaluation using fetal MRI in congenital CMV infection, even in cases with negative neurosonography at diagnosis. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.