CT research: How exactly does the Zika virus affect the developing brain?

Brazilian researchers have teamed up with scientists from Johns Hopkins University School of Medicince to describe certain CT features of Zika-related microcephaly, according to a letter to the editor recently published online in the New England Journal of Medicine.

The scientists analyzed head CT scans obtained at a mean age of 36 days after birth in 23 infants with congenital microcephaly and likely Zika virus infection in the Brazilian state of Pernambuco between September and December 2015.

Among their findings, the researchers reported:

  • Intracranial calcifications were seen in all the infants and mainly involved the frontal lobe (69 to 78 percent) and parietal lobe (83 to 87 percent, with calcifications located mainly at the corticomedullary junction (53 to 86 percent).
  • The configuration of the calcifications was mostly punctate (72 to 100 percent), with a predominately bandlike distribution (56 to 75 percent).
  • The calcifications were seen in the basal ganglia (57 to 65 percent) and in the thalamus (39 to 43 percent).
  • Ventriculomegaly was found in all the infants and was rated as severe in the majority (53 percent) and involving only the lateral ventricles in 43 percent.
  • All the infants had global hypogyration of the cerebral cortex that was severe (only the Sylvian fissure was obviously present) in 78 percent of the infants.
  • Cerebellar hypoplasia was present in 17 of the infants (74 percent) and involved only one cerebellar hemisphere in 3 infants.
  • In all the infants, there was abnormal hypodensity of the white matter, and in 87 percent of the patients it diffusely involved all the cerebral lobes.

“Intrauterine [Zika virus] infection appears to be associated with severe brain anomalies, including calcifications, cortical hypogyration, ventriculomegaly, and white-matter abnormalities,” the researchers concluded.

Read the full letter to the editor.