Central Nervous System Effects of Intrauterine Zika Virus Infection: A Pictorial Review

Relatively few agents have been associated with congenital infections involving the brain. One such agent is the Zika virus, which has caused several outbreaks worldwide and has spread in the Americas since 2015. The Zika virus is an arbovirus transmitted by infected female mosquito vectors, such as the Aedes aegypti mosquito. This virus has been commonly associated with congenital infections of the central nervous system and has greatly increased the rates of microcephaly. Ultrasonography (US) remains the method of choice for fetal evaluation of congenital Zika virus infection. For improved assessment of the extent of the lesions, US should be complemented by magnetic resonance (MR) imaging. Postnatal computed tomography and MR imaging can also unveil additional findings of central nervous system involvement, such as microcephaly with malformation of cortical development, ventriculomegaly, and multifocal calcifications in the cortical-subcortical junction, along with associated cortical atrophy. The calcifications may be punctate, dystrophic, linear, or coarse and may follow a predominantly bandlike distribution. A small anterior fontanelle with prematurely closed sutures is also observed with Zika virus infection. In this review, the prenatal and postnatal neurologic imaging findings of congenital Zika virus infection are covered. Radiologists must be aware of this challenging entity and have knowledge of the various patterns that may be depicted with each imaging modality and the main differential diagnosis of the disease. As in other neurologic infections, serial imaging is able to help demonstrate the progression of the findings. RSNA, 2017.