Advances in pediatric neurovirology

3D Printed Neural Regeneration Devices

Neural regeneration devices interface with the nervous system and can provide flexibility in material choice, implantation without the need for additional surgeries, and the ability to serve as guides augmented with physical, biological (e.g., cellular), and biochemical functionalities. Given the complexity and challenges associated with neural regeneration, a 3D printing approach to the design and manufacturing of neural devices could provide next-generation opportunities for advanced neural regeneration via the production of anatomically accurate geometries, spatial distributions of cellular components, and incorporation of therapeutic biomolecules. A 3D printing-based approach offers compatibility with 3D scanning, computer modeling, choice of input material, and increasing control over hierarchical integration. Therefore, a 3D printed implantable platform could ultimately be used to prepare novel biomimetic scaffolds and model complex tissue architectures for clinical implants in order to treat neurological diseases and injuries. Further, the flexibility and specificity offered by 3D printed in vitro platforms have the potential to be a significant foundational breakthrough with broad research implications in cell signaling and drug screening for personalized healthcare. This progress report examines recent advances in 3D printing strategies for neural regeneration as well as insight into how these approaches can be improved in future studies.

Pediatric Emergency Magnetic Resonance Imaging: Current Indications, Techniques, and Clinical Applications

MR imaging plays an important role in the detection and characterization of several pediatric disease entities that can occur in the emergent setting because of its cross-sectional imaging capability, lack of ionizing radiation exposure, and superior soft tissue contrast. In the age of as low as reasonably achievable, these advantages have made MR imaging an increasingly preferred modality for diagnostic evaluations even in time-sensitive settings. In this article, the authors discuss the current indications, techniques, and clinical applications of MR imaging in the evaluation of pediatric emergencies.

3D printed nervous system on a chip

Bioinspired organ-level in vitro platforms are emerging as effective technologies for fundamental research, drug discovery, and personalized healthcare. In particular, models for nervous system research are especially important, due to the complexity of neurological phenomena and challenges associated with developing targeted treatment of neurological disorders. Here we introduce an additive manufacturing-based approach in the form of a bioinspired, customizable 3D printed nervous system on a chip (3DNSC) for the study of viral infection in the nervous system. Micro-extrusion 3D printing strategies enabled the assembly of biomimetic scaffold components (microchannels and compartmented chambers) for the alignment of axonal networks and spatial organization of cellular components. Physiologically relevant studies of nervous system infection using the multiscale biomimetic device demonstrated the functionality of the in vitro platform. We found that Schwann cells participate in axon-to-cell viral spread but appear refractory to infection, exhibiting a multiplicity of infection (MOI) of 1.4 genomes per cell. These results suggest that 3D printing is a valuable approach for the prototyping of a customized model nervous system on a chip technology.

Brain MRI of children with retinopathy-negative cerebral malaria

Our goals were to understand the brain magnetic resonance imaging (MRI) findings in children with retinopathy-negative cerebral malaria (CM) and investigate whether any findings on acute MRI were associated with adverse outcomes. We performed MRI scans on children admitted to the hospital in Blantyre, Malawi with clinically defined CM. Two hundred and seventeen children were imaged during the study period; 44 patients were malarial retinopathy-negative; and 173 patients were retinopathy-positive. We compared MRI findings in children with retinopathy-negative and retinopathy-positive CM. In children who were retinopathy-negative, we identified MRI variables that were associated with death and adverse neurologic outcomes. On multivariate analysis, cortical diffusion weighted imaging (DWI) abnormality and increased brain volume were strongly associated with neurologic morbidity in survivors. Investigations to explore the underlying pathophysiologic processes responsible for these MRI changes are warranted.

Perinatally HIV-infected youth presenting with acute stroke: progression/evolution of ischemic disease on neuroimaging

BACKGROUND AND PURPOSE

Although HIV infection is decreasing in infants and children, there is a steady cohort of perinatally HIV-infected (PHIV) children that are growing older. Increased risk of acute stroke has been reported in PHIV children. Our goal was to evaluate evolution/progression of neuroimaging findings in PHIV youth initially presenting with acute stroke.

MATERIALS AND METHODS

The medical records of PHIV pediatric patients (n = 179) from 1996 to 2010 were reviewed and patients with clinical documentation of acute stroke referred to the neuroradiology service were eligible for the study. Neuroimaging (brain CT, MRI, and MRA) and charts were evaluated; clinical and neuroimaging findings at the initial acute stroke and at the last presentation to the neuroradiology service were documented and analyzed.

RESULTS

Eight PHIV patients with clinical findings of acute stroke referred to the neuroimaging were identified. CT and MRI findings of infarction were found in all (8/8) patients in their first and/or last neuroimaging study; including basal ganglia-thalami (BGT) infarction (7/8), focal cortical infarction (4/8), and internal capsule infarction (4/8). Imaging depicted cortical atrophy (5/8), BGT calcification (3/8), and posterior reversible encephalopathy syndrome, wallerian degeneration, and periventricular white matter hyperintense T2 signal each in one patient. No tumors or infectious masses, cysts or abscesses were identified. Subsequent available neuroimaging revealed progression of the cerebrovascular disease in seven patients, 5/7 in the absence of new clinical signs or symptoms. Segmental occlusion, narrowing or narrowing/dilatation in the circle of Willis was found in 6/6 patients who underwent MR angiography and fusiform aneurysms were detected in three of them, a saccular aneurysm in one patient.

CONCLUSION

Asymptomatic progression of cerebrovascular disease was found in PHIV adolescents with prior stroke. These findings may have implications for long-term risk and outcomes for this patient population. There should be a low threshold to evaluate for CNS pathology even with minor symptoms in this population. More studies are necessary to determine if there is a benefit from screening of asymptomatic patients.

Neuroimaging of pediatric brain infections

Neuroimaging plays an important and growing role in the diagnosis and therapeutic management of pediatric brain infections. This article describes the spectrum of imaging findings associated with major pediatric viral and bacterial brain infections, outlining the role of current imaging technology in the differential diagnoses of brain injury, detection of complications and therapy monitoring. MRI is the tool of choice in the evaluation of brain infections and particular attention is devoted to the role of diffusion-weighted imaging and magnetic resonance spectroscopy. This article considers viral and bacterial infection in their different modalities of presentation as congenital, acute and subacute/chronic disease. With regard to congenital infections, the growing role of fetal MRI as a valuable complement to ultrasound in the prenatal assessment of brain damage is emphasized.