Neuroimaging clinics of North America
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This article discusses the normal anatomy of the posterior fossa structures followed by a discussion of the characteristic neuroimaging features of a variety of cerebellar and brainstem malformations. In this context, the authors classify posterior fossa malformations based on the neuroimaging pattern into (1) predominantly cerebellar, (2) cerebellar and brainstem, and (3) predominantly brainstem malformations.
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Neuroimaging Clin. N. Am. · Aug 2019
ReviewThe Distal Spine: Normal Embryogenesis and Derangements Leading to Malformation.
The spine and spinal cord are composed of multiple segments initiated by different embryologic mechanisms and advanced under different systems of control. In humans, the upper central nervous system is formed by primary neurulation, the lower by secondary neurulation, and the intervening segment by junctional neurulation. This article focuses on the distal spine and spinal cord to address their embryogenesis and the molecular derangements that lead to some distal spinal malformations.
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Neuroimaging Clin. N. Am. · Aug 2019
ReviewDiffusion Tensor Imaging of Brain Malformations: Exploring the Internal Architecture.
Diffusion tensor imaging (DTI) is an advanced MR imaging technique that provides noninvasive qualitative and quantitative information about the white matter microarchitecture. By measuring the three-dimensional directional characteristics of water molecule diffusion/mobility, DTI generates unique tissue contrasts that are used to study the axonal organization of the central nervous system. Its applications include quantitative evaluation of the brain connectivity, development, and white matter diseases. This article reviews DTI and fiber tractography findings in several brain malformations and highlights the added value of DTI and fiber tractography compared with conventional MR imaging.
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Neuroimaging Clin. N. Am. · Aug 2019
ReviewCorpus Callosum: Molecular Pathways in Mice and Human Dysgeneses.
The corpus callosum is the largest of the 3 telencephalic commissures in eutherian (placental) mammals. Although the anterior commissure, and the hippocampal commissure before being pushed dorsally by the expanding frontal lobes, cross through the lamina reuniens (upper part of the lamina terminalis), the callosal fibers need a transient interhemispheric cellular bridge to cross. This review describes the molecular pathways that initiate the specification of the cells comprising this bridge, the specification of the callosal neurons, and the repulsive and attractive guidance molecules that convey the callosal axons toward, across, and away from the midline to connect with their targets.
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Neuroimaging Clin. N. Am. · Aug 2019
ReviewSpinal Dysraphia, Chiari 2 Malformation, Unified Theory, and Advances in Fetoscopic Repair.
Fetal spina bifida, the most common nonlethal birth defect of the central nervous system, results in substantial neurologic morbidity. The unified theory describes the complex relationship between local spinal lesions and development of Chiari 2 malformation, contributing to hydrocephalus. ⋯ Fetal surgery improves neurologic and motor outcomes, but various approaches, either open hysterotomy or minimally invasive to the uterus, carry substantial obstetric risks. Optimization of the fetoscopic approach aims to minimize maternal and obstetric risks, but data regarding longer-term outcomes are awaited.