Journal of neuroimaging : official journal of the American Society of Neuroimaging
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The events leading up to the development of new multiple sclerosis (MS) lesions on conventional imaging are unknown. The purpose of this study is to use diffusion tensor imaging (DTI) to investigate prelesional changes in MS to better understand the pathological changes that lead to lesion development. ⋯ A significant change in diffusion measures can be seen prior to gadolinium enhancement. Changes in TD drove changes in FA and MD, providing evidence for impaired myelin integrity prior to gadolinium enhancement. DTI may be a sensitive measure for early detection of inflammatory disease activity in MS.
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Spinal cord (SC) pathology is common in multiple sclerosis (MS), and measures of SC-atrophy are increasingly utilized. Normalization reduces biological variation of structural measurements unrelated to disease, but optimal parameters for SC volume (SCV)-normalization remain unclear. Using a variety of normalization factors and clinical measures, we assessed the effect of SCV normalization on detecting group differences and clarifying clinical-radiological correlations in MS. ⋯ SCV-normalization by length improves the ability to detect group differences, strengthens clinical-radiological correlations, and is particularly relevant in settings of subtle disease-related SC-atrophy in MS. SCV-normalization by length may enhance the clinical utility of measures of SC-atrophy.
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Quantitative signal targeting with alternating radiofrequency labeling of arterial regions (QUASAR) is a recent spin labeling technique that could improve the reliability of brain perfusion measurements. Although it is considered reliable for measuring gray matter as a whole, it has never been evaluated regionally. Here we assessed this regional reliability. ⋯ Thus, QUASAR reliability for regional perfusion is high within gray matter, but uncertain within white matter.
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Extraventricular neurocytoma and ganglioneurocytoma are rare intra-axial brain neoplasms that are now recognized as distinct entities in the 2007 WHO classification of brain tumors. We describe the conventional MR imaging, perfusion MRI, proton MR spectroscopy (1H MRS), histopathology, immunohistochemistry, and chromosomal analysis in two cases of these tumors, with some features which have not been previously well described. ⋯ Both tumor types showed an elevated Cho/Cr ratio, but extraventricular ganglioneurocytoma showed a preserved NAA/Cr ratio. These tumors should be considered in the differential diagnosis of intra-axial brain tumors.
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Case Reports
Basilar artery thrombus vs. fenestration: a differential diagnostic challenge in acute ischemic stroke.
We present a case of a man presenting with vertigo and nausea who was found to have multifocal infarcts in the posterior circulation on magnetic resonance imaging (MRI). An magnetic resonance angiography (MRA) demonstrated focal widening and central signal dropout in the distal vertebral artery consistent with arterial fenestration. ⋯ Following the initiation of dual antiplatelet therapy, the signal abnormalities on transcranial doppler (TCD) resolved suggesting dissolution of the thrombus. This case highlights the diagnostic pitfalls that may arise when relying on only one modality for assessing intracranial vasculature and the importance of clarifying the diagnosis of basilar thrombosis or fenestration.