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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Prenatal imaging of the central nervous system has proven to be essential in the detection of anomalies to guide counseling and intrauterine and postnatal therapies. However, understanding the appearance of normal is important because the fetal brain changes dramatically during the pregnancy. ⋯ The initial section stresses techniques for both modalities. The second section describes ultrasound and MR landmarks in a normal fetal brain.
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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
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.
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Neuroimaging Clin. N. Am. · May 2019
ReviewThe Connection Between Patent Foramen Ovale and Migraine.
"Observational studies have identified a relationship between patent foramen ovale (PFO) and migraine headache. In people who have migraine with aura, 40% to 60% have a PFO, compared with 20% to 30% in the general adult population. It is hypothesized that migraine, especially migraine with aura, may be triggered by hypoxemia or vasoactive chemicals (eg, serotonin), which are ordinarily metabolized during passage through the lungs. Although PFO closure is currently not a FDA-approved therapy for migraines, randomized trials suggest that this intervention may benefit a subgroup of migraineurs."