An MRI evaluation of grey matter damage in African Americans with MS

Objective: Multiple sclerosis (MS) is less prevalent in African Americans (AAs) than Caucasians (CAs) but in the former the disease course tends to be more severe. In order to clarify the MRI correlates of disease severity in AAs, we performed a multimodal brain MRI study to comprehensively assess the extent of grey matter (GM) damage and the degree of functional adaptation to structural damage in AAs with MS. Methods: In this cross-sectional study, we characterized GM damage in terms of focal lesions and volume loss and functional adaptation during the execution of a simple motor task on a sample of 20 AAs and 20 CAs with MS and 20 healthy controls (CTRLs). Results: In AAs, we observed a wider range of EDSS scores than CAs, with multisystem involvement being more likely in AAs (p < 0.01). While no significant differences were detected in lesion loads and global brain volumes, AAs showed regional atrophy in the posterior lobules of cerebellum, temporo-occipital and frontal regions in comparison with CAs (p < 0.01), with cerebellar atrophy being the best metric in differentiating AAs from CAs (p = 0.007, AUC = 0.96 and p = 0.005, AUC = 0.96, respectively for right and left cerebellar clusters). In AAs, the functional analysis of cortical activations showed an increase in task-related activation of areas involved in high level processing and a decreased activation in the medial prefrontal cortex compared to CAs. Interpretation: In our study, the direct comparison of AAs and CAs points to cerebellar atrophy as the main difference between subgroups

Sodium imaging as a marker of tissue injury in patients with multiple sclerosis

Recent studies have suggested that intra-axonal sodium accumulation contribute to axonal degeneration in patients with MS. Advances in MRI hardware and software allow acquisition of brain sodium signal in vivo. This review begins with a summary of the experimental evidence for impairment of sodium homeostasis in MS. Then, MRI methods for sodium acquisition are reviewed and the application of the techniques in patients with MS is discussed. Sodium imaging and ultra-high field MRI have the potential to provide tissue-specific markers of neurodegeneration in MS. © 2013 Elsevier B.V

Atrophy mainly affects the limbic system and the deep grey matter at the first stage of multiple sclerosis

International audienceThe existence of grey matter (GM) atrophy right after the first clinical event suggestive of multiple sclerosis (MS) remains controversial. The aim of this study was therefore to establish whether regional GM atrophy is already present in the earliest stage of MS assessing regional GM atrophy in a large group of patients. Sixty two patients with a clinically isolated syndrome (CIS) were examined on a 1.5T MR imager within six months after their first clinical events. A group of thirty seven matched healthy control subjects were also included in the study. An optimized Voxel Based Morphometric (VBM) method customised for MS was applied on volumetric T1-weighted images. The functional status of patients was assessed using the Expanded Disability Status Scale (EDSS) and the Brief Repeatable Battery. VBM analysis (p<0.005, FWE corrected) on patients versus control subjects showed the presence of significant focal GM atrophy in patients involving the bilateral insula, the bilateral orbitofrontal cortices, the bilateral internal and inferior temporal regions, the posterior cingulate cortex, the bilateral thalami, the bilateral caudate nuclei, the bilateral lenticular nuclei, and the bilateral cerebellum. EDSS was slightly correlated (rho=-0.37 p=0.0027) with the atrophy of the right cerebellum. No correlations have been evidenced between the cognitive status of patients and the regional GM atrophy. The present study performed on a large group of CIS patients demonstrated that regional GM atrophy is present right after the first clinical event of multiple sclerosis and mainly affects the deep GM and the limbic system

Validation and Initial Results from Dynamic 23Na fMRI

International audienceIn this abstract we develop and validate an MRI acquisition/reconstruction method to derive the temporal dynamics of 23Na within a 20 min scan

The use of SPIRIT to reject and replace motion-corrupted data

International audienceThe SPIRIT parallel imaging algorithm was evaluated for use in a data rejection and replacement scheme to reduce motion artefacts

Sodium imaging as a marker of tissue injury in patients with multiple sclerosis

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Sodium short and long T2* components in the normal human brain: a multi-TE 23Na MRI study at 7T

International audienceThe study aimed to provide values of the short and long T2* sodium components of the human brain at 7T using a multi-echoes 23Na MRI approach (n=24 TE). These results may help improving sodium quantification at 7T