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- Advanced Multicompartment Diffusion MRI Models and Their Application in Multiple Sclerosis
In this review, the authors provide an appraisal of the current literature on the physics principles, histopathologic validation, and clinical applications of advanced diffusion techniques in both brains and spinal cords of patients with MS (neurite orientation dispersion and density imaging, diffusion basis spectrum imaging, multicompartment microscopic diffusion MR imaging with the spherical mean technique, and models enabled through high-gradient diffusion MR imaging). They discuss limitations of each of the methods and directions that future research could take to provide additional validation of their roles as biomarkers of axonal and myelin injury in MS.
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- The Impact of Intracortical Lesions on Volumes of Subcortical Structures in Multiple Sclerosis
The authors investigated the impact of intracortical lesions on the volumes of subcortical structures (especially the thalamus) compared with other lesions in 71 patients with MS. The volumes of intracortical lesions and white matter lesions were identified on double inversion recovery and FLAIR imaging, respectively, by using 3D Slicer. Volumes of white matter T1 hypointensities and subcortical gray matter, thalamus, caudate, putamen, and pallidum volumes were calculated using FreeSurfer. They conclude that thalamic atrophy was explained better by intracortical lesions than by white matter lesion and T1 hypointensity volumes, especially in patients with more profound disability.
- Predictors of Cerebral Aneurysm Rupture after Coil Embolization: Single-Center Experience with Recanalized Aneurysms
The authors evaluated a total of 426 unruptured aneurysms and 169 ruptured aneurysms that underwent coil embolization in their institution between January 2009 and December 2017. Recanalization occurred in 38 (8.9%) of 426 unruptured aneurysms and 37 (21.9%) of 169 ruptured aneurysms. The Modified Raymond-Roy Classification on DSA was used to categorize the recanalization type. In untreated recanalized aneurysms, class IIIb aneurysms ruptured significantly more frequently than class II and IIIa. In the ruptured group, the median follow-up term was 28.0 months. Retreatment for recanalization was performed in 16 aneurysms. Four of 21 untreated recanalized aneurysms (2.37% of total coiled aneurysms) ruptured. Class IIIb aneurysms ruptured significantly more frequently than class II and IIIa. Coiled aneurysms with class IIIb recanalization should undergo early retreatment because of an increased rupture risk.
- MR Imaging Correlates for Molecular and Mutational Analyses in Children with Diffuse Intrinsic Pontine Glioma
Initial MRIs from 50 subjects with diffuse intrinsic pontine gliomas recruited for a prospective clinical trial before treatment were analyzed. Retrospective imaging analyses included FLAIR/T2 tumor volume, tumor volume enhancing, the presence of cyst and/or necrosis, median, mean, mode, skewness, kurtosis of ADC tumor volume based on FLAIR, and enhancement at baseline. Molecular subgroups based on EGFR and MGMT mutations were established. Histone mutations were also determined (H3F3A, HIST1H3B, HIST1H3C). Enhancing tumor volume was near-significantly different across molecular subgroups, after accounting for the false discovery rate. Tumor volume enhancing, median, mode, skewness, and kurtosis ADC T2-FLAIR/T2 were significantly different between patients with H3F3A and HIST1H3B/C mutations.
- Cerebellar Watershed Injury in Children
Focal signal abnormalities at the depth of the cerebellar fissures in children have been reported and hypothesized to represent a novel pattern of bottom-of-fissure dysplasia. The authors report a series of 23 patients with a similar distribution and appearance of cerebellar signal abnormality attributable to watershed injury. T2 prolongation was observed at the depths of the cerebellar fissures bilaterally in all 23 patients, centered at the expected location of the deep cerebellar vascular borderzone. Diffusion restriction was associated with MR imaging performed during acute injury in 13/16 patients. Five of 23 patients had prior imaging, all demonstrating a normal cerebellum. The etiology of injury was hypoxic-ischemic injury in 17/23 patients, posterior reversible encephalopathy syndrome in 3/23 patients, and indeterminate in 3/23 patients.
- Sensitivity of the Inhomogeneous Magnetization Transfer Imaging Technique to Spinal Cord Damage in Multiple Sclerosis
Anatomic images covering the cervical spinal cord from the C1 to C6 levels and DTI, magnetization transfer/inhomogeneous magnetization transfer images at the C2/C5 levels were acquired in 19 patients with MS and 19 paired healthy controls. Anatomic images were segmented in spinal cord GM and WM, both manually and using the AMU40 atlases. MS lesions were manually delineated. MR imaging metrics were analyzed within normal-appearing and lesion regions in anterolateral and posterolateral WM and compared using Wilcoxon rank tests and z scores. The use of a multiparametric MR imaging protocol combined with an automatic template-based GM/WM segmentation approach in the current study outlined a higher sensitivity of the ihMT technique toward spinal cord pathophysiologic changes in MS compared with atrophy measurements, DTI, and conventional MT. The authors also conclude that the clinical correlations between ihMTR and functional impairment observed in patients with MS also argue for its potential clinical relevance, paving the way for future longitudinal multicentric clinical trials in MS.
35 Years Ago in AJNR
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