Importance of Neuroimaging in the Evaluation of Zika Virus-Exposed Infants

Neurodevelopmental outcomes in congenital and perinatal infections

PURPOSE OF REVIEW

Congenital infections are a major cause of childhood multidomain neurodevelopmental disabilities. They contribute to a range of structural brain abnormalities that can cause severe neurodevelopmental impairment, cerebral palsy, epilepsy, and neurosensory impairments. New congenital infections and global viral pandemics have emerged, with some affecting the developing brain and causing neurodevelopmental concerns. This review aims to provide current understanding of fetal infections and their impact on neurodevelopment.

RECENT FINDINGS

There are a growing list of congenital infections causing neurodevelopmental issues, including cytomegalovirus, Zika virus, syphilis, rubella, lymphocytic choriomeningitis virus, and toxoplasmosis. Fetal exposure to maternal SARS-CoV-2 may also pose risk to the developing brain and impact neurodevelopmental outcomes, although studies have conflicting results. As Zika virus was a recently identified congenital infection, there are several new reports on child neurodevelopment in the Caribbean and Central and South America. For many congenital infections, children with in-utero exposure, even if asymptomatic at birth, may have neurodevelopmental concerns manifest over time.

SUMMARY

Congenital infections should be considered in the differential diagnosis of a child with neurodevelopmental impairments. Detailed pregnancy history, exposure risk, and testing should guide diagnosis and multidisciplinary evaluation. Children with congenital infections should have long-term follow-up to assess for neurodevelopmental delays and other neurosensory impairments. Children with confirmed delays or high-risk should be referred for rehabilitation therapies.

Clinical and neurodevelopmental outcomes based on brain imaging studies in a Colombian cohort of children with probable antenatal Zika virus exposure

BACKGROUND

Our aim was to describe the neuroimaging and clinical evaluations of children with antenatal Zika-virus (ZIKV) exposure.

METHODS

The Colombian National Institute of Health performed serial clinical evaluations of children with probable antenatal ZIKV exposure (i.e., born to ZIKV symptomatic mothers or born with birth defects compatible with ZIKV infection, regardless of laboratory results) over 2 years that included head circumference (HC), eye examination, and neurodevelopmental assessments. Clinical neuroimaging studies (head computed tomography and/or brain magnetic resonance imaging) were analyzed for abnormalities, two-dimensional measurements were made of the right and left frontal and occipital cortical thickness. Two abnormal patterns were defined: Pattern 1 (sum of four areas of cortex <6 cm) and Pattern 2 (sum of four areas of cortex ≥6 cm and < 10 cm).

RESULTS

Thirty-one children had a neuroimaging study; in 24, cortical thickness was measured. The median age at the first visit was 8 (range: 6-9) months and 22 (range: 19-42) months at the last evaluation. In the 24 cases with cortical measurements, three were normal, 12 were in Pattern 1, and nine were in Pattern 2. Children within Pattern 1 had lower mean HC at birth and in follow-up (both p < .05) and a higher frequency of structural eye abnormalities (p < .01). A trend towards poorer neuromotor development was seen in Pattern 1, although not statistically significant (p = .06).

CONCLUSION

Brain imaging classification based on cortical measurements correlate with ophthalmologic abnormalities and HC. Cortical thickness may be a marker for clinical outcomes in children with congenital ZIKV infection.

Neuroimaging in Children Born With Congenital Zika Syndrome: A Cohort Study

BACKGROUND AND PURPOSE

Neuroimaging findings have been associated with adverse neurologic outcomes in children with congenital Zika virus infection. Our purpose is to describe the brain magnetic resonance imaging (MRI) of children around 3 years of age, born with congenital Zika syndrome.

METHODS

This cohort study followed 62 children born with congenital Zika syndrome who had head computed tomography (CT) performed during the first months of life. All these children had clinical, neuroimaging, and serological confirmation of congenital Zika. Around 3 years of age, these children received a brain MRI.

RESULTS

In 35 children, we could perform an MRI. All these children had severe impairment in neuromotor development. In general, the examinations showed the same alterations of the CT examinations: delayed myelination (82.8%), intracranial calcification (71.4%) although with decreased intensity and size as compared with previously CT examinations, ventriculomegaly (91.4%), cerebellar hypoplasia (68.5%), and cortical development abnormalities (85.8%).

CONCLUSION

The serious brain alterations observed through head CT examinations in children born with congenital Zika syndrome continued to be detected through an MRI examination carried out at around 3 years of age. This indicates a poor prognosis for these children who had a severe neuromotor development delay.

Cranial US in Infants Exposed to Zika Virus: The NATZIG Cohort

Background Studies addressing neuroimaging findings as primary outcomes of congenital Zika virus infection are variable regarding inclusion criteria and confirmatory laboratory testing. Purpose To investigate cranial US signs of prenatal Zika virus exposure and to describe frequencies of cranial US findings in infants exposed to Zika virus compared to those in control infants. Materials and Methods In this single-center prospective cohort study, participants were enrolled during the December 2015-July 2016 outbreak of Zika virus infection in southeast Brazil (Natural History of Zika Virus Infection in Gestation cohort). Eligibility criteria were available cranial US and laboratory findings of maternal Zika virus infection during pregnancy confirmed with RNA polymerase chain reaction testing (ie, Zika virus-exposed infants). The control group was derived from the Zika in Infants and Pregnancy cohort and consisted of infants born to asymptomatic pregnant women who tested negative for Zika virus infection during pregnancy. Two radiologists who were blinded to the maternal Zika virus infection status independently reviewed cranial US scans from both groups and categorized them as normal findings, Zika virus-like pattern, or mild findings. Associations between cranial US findings and prenatal Zika virus exposure were assessed with univariable analysis. Results Two hundred twenty Zika virus-exposed infants (mean age, 53.3 days ± 71.1 [standard deviation]; 113 boys) and born to 219 mothers infected with Zika virus were included in this study and compared with 170 control infants (mean age, 45.6 days ± 45.8; 102 boys). Eleven of the 220 Zika virus-exposed infants (5%), but no control infants, had a Zika virus-like pattern at cranial US. No difference in frequency of mild findings was observed between the groups (50 of 220 infants [23%] vs 44 of 170 infants [26%], respectively; P = .35). The mild finding of lenticulostriate vasculopathy, however, was nine times more frequent in Zika virus-exposed infants (12 of 220 infants, 6%) than in control infants (one of 170 infants, 1%) (P = .01). Conclusion Lenticulostriate vasculopathy was more common after prenatal exposure to Zika virus, even in infants with normal head size, despite otherwise overall similar frequency of mild cranial US findings in Zika virus-exposed infants and in control infants. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Benson in this issue.