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.

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.

Neuroimaging and genetic influence in treating brain neoplasms.

The current treatment of glioblastoma patients based on surgery, radiation, and chemotherapy has achieved modest improvement in progression-free survival. In this direction, personalized treatment is the next achievement for better patient management and increased overall survival. Genetic characterization of high-grade gliomas by MR imaging is the goal in neuroimaging. The main genetic alterations described in these neoplasms, implications in patient treatment, and prognosis are reviewed. MR imaging features and novel techniques are correlated with the main genetic aspects of such tumors. Posttreatment phenomena, such as pseudoprogression and pseudoresponse, are analyzed in association with the genetic expression of these tumors.

Diffusion MR imaging: an important tool in the assessment of brain tumors.

For over 20 years, conventional MR imaging has been used for assessing brain tumors. However, conventional MR imaging tends to underestimate the extent of the tumor, perhaps leading to suboptimal treatment. New MR imaging tools have been widely used to determine the grade, heterogeneity, and extent of brain tumors. Diffusion-weighted imaging has been studied extensively, helping in tumor grading, differential diagnosis, and postoperative evaluation. Diffusion tensor imaging can apparently delineate more accurately the tumor versus the infiltrating tumor between the peritumoral edema and the normal brain parenchyma. This article shows the main clinical applications of these sequences.

Diffusion magnetic resonance imaging in multiple sclerosis.

Multiple sclerosis (MS) is considered the most common inflammatory autoimmune neurologic disorder and the most frequent cause of nontraumatic neurologic disability in young and middle-age adults. This article reviews the basic features of its magnetic resonance (MR) imaging lesions and, primarily, the use of diffusion MR imaging, which is increasingly applied to assess patients with MS, not only to investigate plaques but also the normal-appearing white matter, gray matter, optic nerve, and spinal cord, because of its ability to detect and quantify disease-related pathologic conditions of the central nervous system.