Sequential Prenatal, Postnatal Neuroimaging in Zika-Exposed Infants

Sequential neuroimaging indicated that prenatal and postnatal ultrasonography may identify Zika virus-related brain abnormalities in most patients, according to results published in JAMA Pediatrics.

A cohort of pregnant women from Colombia (n=80) and Washington, DC (n=2), with clinical criteria for Zika infection were enrolled and received 1 or more magnetic resonance imaging (MRI) and ultrasound examinations during the second and/or third trimesters. The infants underwent brain MRI and cranial ultrasound postnatally and blood samples were tested for Zika virus.

In 3 of the cases, fetal MRI demonstrated abnormalities that were consistent with congenital Zika infection; 2 of these infants had heterotopias and malformations in cortical development; the third infant had a parietal encephalocele, Chiari II malformation, and microcephaly. 

In 1 case, ultrasound results were normal while MRI detected abnormalities. Postnatal MRI was performed on 53 of 79 infants whose prenatal imaging results were normal and, of these, 7 had mild abnormalities. Postnatal cranial ultrasound was done on 57 infants and changes of lenticulostriate vasculopathy, choroid plexus cysts, germinolytic/subependymal cysts, and/or calcification were detected in 21 infants.

The study was limited by differences in timing of maternal infection, symptoms, Zika virus testing, MRI, ultrasound and fetal MRI technique, and incomplete postnatal imaging. There are also known limitations to Zika virus laboratory testing, specifically in places with circulating Zika and other Flaviviruses, as well as multiple opportunities for exposure.

Study investigators concluded that findings from sequential fetal neuroimaging in pregnancies complicated by Zika virus were normal in most cases, but in the small number of positive studies, the findings were severely abnormal. The study authors recommended postnatal imaging, as it may be able to detect changes not seen on fetal imaging and supports current US Centers for Disease Control and Prevention guidelines for postnatal cranial ultrasound. Study authors also highlighted “a need for long-term follow-up to assess the neurodevelopmental significance of these early neuroimaging findings, both normal and abnormal” and noted that some of these studies are currently underway.

Reference

Mulkey SB, Bulas DI, Vezina G, et al. Sequential neuroimaging of the fetus and newborn with in utero Zika virus exposure [published online November 26 2018]. JAMA Pediatr. doi: 10.1001/jamapediatrics.2018.4138