Neuroimaging clinics of North America
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Normal brain development is best evaluated by MR imaging in the fetal and pediatric patient. As the developing brain grows, myelinates, and sulcates rapidly, understanding the normal appearance of the brain throughout development is critical. ⋯ Sensory axons generally myelinate before motor axons with central to peripheral and dorsal to ventral myelination gradients. By 2 years of age, the brain has a near adult appearance by conventional anatomic MR imaging.
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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
ReviewDisorders of Ventral Induction/Spectrum of Holoprosencephaly.
Disorders of the ventral induction give rise to a group of congenital malformations that share in common the failure of the prosencephalon cleavage and subsequent formation of midline structures, presenting with a wide spectrum of severity. This article focuses on the imaging findings of the holoprosencephaly spectrum and septo-optic dysplasia, their epidemiology, embryology, and the common clinical associated anomalies. Knowledge of the imaging features of these disorders is necessary for a correct interpretation of findings and accurate parental counseling. Diagnostic evaluation of patients should include molecular screening and genetic counseling to characterize prognosis and risk of recurrence.
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Neuroimaging Clin. N. Am. · Aug 2019
ReviewConnectomics in Brain Malformations: How Is the Malformed Brain Wired?
A new neuroimaging dimension is currently being adopted. The structural connectome reveals macroscale white matter connectivity of the human brain, providing insights into brain networks organization. ⋯ Connectomics provides a powerful set of network measures, which can serve as noninvasive biomarkers for the diagnosis, prognostication, and treatment response of children. We discuss the principles of connectome reconstruction and visualization of the pediatric structural connectome using current state-of-the-art neuroimaging and postprocessing techniques, and we describe potential connectomics applications to study brain 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.