Fetal and Postnatal Brain Imaging for the Detection of ZIKV Encephalopathy in the Fetus/Newborn

Abstract

Background. Up to 15% of pregnancies complicated by maternal ZIKV infection result in Zika-virus associated brain abnormalities in the fetus/newborn. Fetal ultrasound (feUS) is the standard imaging modality for the evaluation of fetal anatomy and for brain changes from congenital infection. Fetal MRI (feMRI) may be a useful adjunct. Methods. We performed a prospective longitudinal neuroimaging study of fetuses/newborns of pregnant women with clinical and/or lab confirmed (RT-PCR and/or IgM/PRNT) diagnosis of Zika infection in Barranquilla, Colombia (endemic) and in Washington, DC, USA (travel-related). Gestational age (GA) at exposure and timing between ZIKV exposure/symptoms and imaging was documented. Subjects had one to two feMRIs and feUS, depending upon GA at enrollment. The feMRI and feUS protocols were standardized between sites and studies were centrally interpreted at Children's National. Postnatally, infants received an unsedated brain MRI and head US. Results. Forty-eight, ZIKV exposed/infected in first or second trimester pregnant women were enrolled (46 Colombia, 2 USA). Subjects had symptoms of ZIKV infection at mean of 8.4 +/- 5.7 week GA. The first feMRI and feUS were performed at 25.1 +/- 6.3 week GA. Tirty-six infants had a second feMRI and feUS at 31.1 +/- 4.2 week GA. Tree of 48 (6%) cases had an abnormal feMRI: (1) heterotopias and abnormal cortical indent; (2) parietal encephalocele and Chiari II; (3) thin corpus callosum, dys-plastic brainstem, temporal cysts, subependymal heterotopias, and generalized cere-bral/cerebellar atrophy. FeUS in these three cases found (1) normal study; (2) parietal encephalocele and Chiari II; (3) significant ventriculomegaly with decreasing percen-tiles of head circumference from 32 to 36 week GA (38% to 3.6%). Postnatal head US revealed findings not seen on feUS: choroid plexus or germinal matrix cysts in nine infants and lenticulostriate vasculopathy in one infant. Conclusion. FeMRI and feUS provide complimentary information in the assessment of fetal brain changes in ZIKV. In cases of abnormal brain structure, feMRI reveals more extensive areas of brain damage than is seen by US. Further studies are needed to determine whether cystic changes on postnatal head US are related to ZIKV infection, or are incidental findings.