Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Diffusion-weighted imaging is able to capture important information about cerebral white matter (WM) structure. However, diffusion data can suffer from MRI and biological noise that degrades the quality of the images and makes finding important features difficult. We investigated how effectively local and nonlocal denoising increased the sensitivity to detect differences in cerebral WM in neuroHIV. ⋯ PCA denoising had a beneficial effect on detecting significant differences in PWH after sample size reduction. The smaller forceps minor tract and right uncinate fasciculus showed greater sensitivity to PCA denoising than the larger corpus callosum. These results show the importance of identifying the most effective PCA denoising strategy when investigating WM in PWH.
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Corpus callosum (CC) atrophy is a strong predictor of multiple sclerosis (MS) disability but the contributing pathological mechanisms remain uncertain. We aimed to apply advanced MRI to explore what drives the often nonuniform callosal atrophy. ⋯ Both white matter and cortical lesions contribute to regional corpus callosal atrophy. The lobe-specific lesion topology does not fully explain the inhomogeneous CC atrophy.
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Ultra-high-field 7.0 Tesla (T) MRI offers substantial gains in signal-to-noise ratio (SNR) over 3T and 1.5T, but for over two decades has remained a research tool, while 3T scanners have achieved widespread clinical use. This much slower translation of 7T relates to daunting technical challenges encountered in ultra-high-field human MR imaging. The recent introduction of United States Food and Drug Administration (FDA)-approved clinical 7T scanners promises to be a watershed for many 7T neuroimaging applications, including epilepsy imaging. ⋯ We describe a tiered epilepsy imaging strategy and protocols designed to optimize 7T value and work around signal intensity variation and signal loss artifacts, which remain significant challenges to full exploitation of 7T clinical value. We describe FDA-approved techniques for mitigating these artifacts and briefly outline techniques currently under development, but not yet FDA approved. Finally, we discuss the major issues in 7T patient safety and toleration, outlining their physical causes and effects on workflow, and provide references to more comprehensive technical reviews for readers seeking greater technical detail.
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Angiocentric gliomas (AGs) are epileptogenic low-grade gliomas in young patients. We aimed to investigate the MRI findings of AGs and systematically review previous publications and three new cases. ⋯ Intratumoral T1-weighted high-intensity areas, stalk-like signs, and regional brain atrophy were frequent imaging features in AG. We also found that affected age was different between supratentorial and brainstem AGs.