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.

Three-dimensional reconstruction of fetal abnormalities using ultrasonography and magnetic resonance imaging.

Objective: We aimed to compare three-dimensional (3D) fetal malformation images obtained using ultrasonography (US) and magnetic resonance imaging (MRI) on the same day during the third trimester of pregnancy. Methods: Total 33 fetuses were selected from cases evaluated for malformations. Morphological abnormalities were first scanned using 3DUS. MRI was used to confirm the previous preliminary 3DUS findings, and diagnoses were confirmed postnatally. 3DUS scans were performed transabdominally using an Rab (4-8 L) probe, Voluson 730 Pro/Expert and E8 (General Electric, Healthcare, Zipf, Austria). MRI was performed using a 1.5-T scanner (Magneton Avanto, Siemens, Erlangen, Germany) with a body coil. The 3D reconstruction of the structure of interest was manually performed from a True FISP sequence using an interactive pen tablet (Syngo multimodality 2009B, Siemens, Erlangen, Germany). Results: Despite recent advancements in 3DUS, the quality of 3D images obtained from MRI was superior during the third trimester. 3DUS had certain limitations, such as being influenced by the fetal position, the volume of amniotic fluid, and maternal obesity. Fetal movements during image acquisition were one of the main challenges for MRI. Conclusion: The quality of the 3D images obtained using MRI was superior to that of images obtained using US during the third trimester of pregnancy.

Association Between Neonatal Neuroimaging and Clinical Outcomes in Zika-Exposed Infants From Rio de Janeiro, Brazil.

Importance: Congenital Zika virus (ZIKV) infection may present with a spectrum of clinical and neuroradiographic findings. Objective: To determine whether neuroimaging findings for infants with a history of ZIKV exposure are associated with infant clinical outcomes and gestational age at antenatal ZIKV infection. Design, Setting, and Participants: This cohort study retrospectively reviewed neuroimaging results (computed tomography and/or magnetic resonance imaging scans) of 110 ZIKV-exposed infants from a maternity and children's hospital in Rio de Janeiro, Brazil, following the 2015 to 2016 ZIKV epidemic. Neuroimaging from March 1, 2016, to June 30, 2017, was evaluated to determine whether findings were associated with clinical outcomes and the timing of maternal ZIKV infection. Data were analyzed from July 1, 2017, to August 30, 2018. Exposures: Neuroimaging (computed tomography and/or magnetic resonance imaging) was performed on ZIKV-exposed infants after birth. Blood and/or urine specimens from mothers and infants were tested for ZIKV by polymerase chain reaction assay. Main Outcomes and Measures: Neuroimaging studies were evaluated for structural abnormalities and other forms of brain injury. Results: A total of 110 infants with a mean (SD) gestational age of 38.4 (2.1) weeks had neuroimaging and clinical outcome data reviewed. Of these, 71 (65%) had abnormal neuroimaging findings, with the majority (96%) classified as having severe ZIKV infection at birth. The most common neuroimaging abnormalities were structural abnormalities including brain calcifications, especially at the cortico-subcortical white matter junction, cortex malformations, ventriculomegaly, and reduced brain volumes, followed by brainstem hypoplasia, cerebellar hypoplasia, and corpus callosum abnormalities. Frequency of abnormal imaging was higher in infants with specific clinical findings as opposed to those without them; these findings included fetal brain disruption sequence (100% vs 35%), microcephaly (100% vs 30%), congenital contractures (100% vs 58%), ophthalmologic abnormalities (95% vs 44%), hearing abnormalities (100% vs 58%), and neurologic symptoms (94% vs 10%). Four of 39 infants (10%) without initial evidence of severe ZIKV infection and normal findings on neurologic evaluation at birth had abnormal neuroimaging findings. Neuroimaging abnormalities differed by trimester of maternal ZIKV infection, with 63% of infants born to mothers infected in the first trimester, 13% of infants born to mothers infected in the second trimester, and 1% of infants born to mothers infected in the third trimester exhibiting neuroimaging abnormalities. The odds of abnormal neuroimaging were 7.9 times greater for infants with first trimester ZIKV exposure compared with other trimesters combined (odds ratio, 7.9; 95% CI, 3.0-20.4; P < .001). Conclusions and Relevance: Neuroimaging abnormalities of computed tomography and/or magnetic resonance imaging scans were common in ZIKV-exposed infants. While neuroimaging abnormalities were seen in 10% of infants without clinically severe ZIKV, most occurred almost exclusively among those with clinically severe ZIKV, especially among those with a history of ZIKV exposure in the first trimester.