78 research outputs found
Assessing brain connectivity at rest is clinically relevant in early multiple sclerosis
No full textFaivre, Anthony Rico, Audrey Zaaraoui, Wafaa Crespy, Lydie Reuter, Francoise Wybrecht, Delphine Soulier, Elisabeth Malikova, Irina Confort-Gouny, Sylviane Cozzone, Patrick J Pelletier, Jean Ranjeva, Jean-Philippe Audoin, Bertrand Research Support, Non-U.S. Gov't England Multiple sclerosis (Houndmills, Basingstoke, England) Mult Scler. 2012 Sep;18(9):1251-8. doi: 10.1177/1352458511435930. Epub 2012 Feb 3.OBJECTIVE: The present study aims to determine the clinical counterpart of brain resting-state networks reorganization recently evidenced in early multiple sclerosis. METHODS: Thirteen patients with early relapsing-remitting multiple sclerosis and 14 matched healthy controls were included in a resting state functional MRI study performed at 3 T. Data were analyzed using group spatial Independent Component Analysis using concatenation approach (FSL 4.1.3) and double regression analyses (SPM5) to extract local and global levels of connectivity inside various resting state networks (RSNs). Differences in global levels of connectivity of each network between patients and controls were assessed using Mann-Whitney U-test. In patients, relationship between clinical data (Expanded Disability Status Scale and Multiple Sclerosis Functional Composite Score - MSFC) and global RSN connectivity were assessed using Spearman rank correlation. RESULTS: Independent component analysis provided eight consistent neuronal networks involved in motor, sensory and cognitive processes. For seven RSNs, the global level of connectivity was significantly increased in patients compared with controls. No significant decrease in RSN connectivity was found in early multiple sclerosis patients. MSFC values were negatively correlated with increased RSN connectivity within the dorsal frontoparietal network (r = -0.811, p = 0.001), the right ventral frontoparietal network (r = - 0.587, p = 0.045) and the prefronto-insular network (r = -0.615, p = 0.033). CONCLUSIONS: This study demonstrates that resting state networks reorganization is strongly associated with disability in early multiple sclerosis. These findings suggest that resting state functional MRI may represent a promising surrogate marker of disease burden
Voxelwise analysis of conventional magnetic resonance imaging to predict future disability in early relapsing-remitting multiple sclerosis
No full textWybrecht, Delphine Reuter, Francoise Zaaraoui, Wafaa Faivre, Anthony Crespy, Lydie Rico, Audrey Malikova, Irina Confort-Gouny, Sylviane Soulier, Elisabeth Cozzone, Patrick J Pelletier, Jean Ranjeva, Jean-Philippe Audoin, Bertrand England Multiple sclerosis (Houndmills, Basingstoke, England) Mult Scler. 2012 Nov;18(11):1585-91. doi: 10.1177/1352458512442991. Epub 2012 Mar 27.BACKGROUND: The ability of conventional magnetic resonance imaging (MRI) to predict subsequent physical disability and cognitive deterioration after a clinically isolated syndrome (CIS) is weak. OBJECTIVES: We aimed to investigate whether conventional MRI changes over 1 year could predict cognitive and physical disability 5 years later in CIS. We performed analyses using a global approach (T(2) lesion load, number of T(2) lesions), but also a topographic approach. METHODS: This study included 38 patients with a CIS. At inclusion, 10 out of 38 patients fulfilled the 2010 revised McDonald's criteria for the diagnosis of multiple sclerosis. Expanded Disability Status Scale (EDSS) evaluation was performed at baseline, year 1 and year 5, and cognitive evaluation at baseline and year 5. T(2)-weighted MRI was performed at baseline and year 1. We used voxelwise analysis to analyse the predictive value of lesions location for subsequent disability. RESULTS: Using the global approach, no correlation was found between MRI and clinical data. The occurrence or growth of new lesions in the brainstem was correlated with EDSS changes over the 5 years of follow-up. The occurrence or growth of new lesions in cerebellum, thalami, corpus callosum and frontal lobes over 1 year was correlated with cognitive impairment at 5 years. CONCLUSION: The assessment of lesion location at the first stage of multiple sclerosis may be of value to predict future clinical disability
Intrathecal synthesis of IgM measured after a first demyelinating event suggestive of multiple sclerosis is associated with subsequent MRI brain lesion accrual
No full textDurante, Laurence Zaaraoui, Wafaa Rico, Audrey Crespy, Lydie Wybrecht, Delphine Faivre, Anthony Reuter, Francoise Malikova, Irina Pommier, Gilbert Confort-Gouny, Sylviane Cozzone, Patrick J Ranjeva, Jean-Philippe Pelletier, Jean Boucraut, Jose Audoin, Bertrand Research Support, Non-U.S. Gov't England Multiple sclerosis (Houndmills, Basingstoke, England) Mult Scler. 2012 May;18(5):587-91. Epub 2011 Sep 30.BACKGROUND: Previous studies have demonstrated that intrathecal synthesis of IgM is observed in multiple sclerosis (MS) and correlates with a worse disease course. These results suggest that IgM participates in the formation of MS lesions. OBJECTIVE: The aim of the present study was to assess the potential association between the level of intrathecal synthesis of IgM measured after a clinically isolated syndrome (CIS) and the subsequent formation of brain lesions. METHODS: Fifty seven patients with a CIS and a high risk developing MS were enrolled in a longitudinal study. Examination of cerebrospinal fluid was performed after the CIS and included measures of intrathecal IgM and IgG synthesis. Patients were assessed with the same 1.5 Tesla magnetic resonance imaging (MRI) system at baseline and after a mean follow-up period of 49 months (range 36-60). Spearman Rank correlation was used to assess the potential correlations between levels of intrathecal immunoglobulin synthesis and MRI data. RESULTS: The level of intrathecal IgM synthesis was correlated with the number of gadolinium-enhancing lesions at baseline (p = 0.01) and with accrual of brain lesions during the follow-up period (p = 0.02). By taking into account brain sub-regions, we demonstrated that the level of intrathecal IgM synthesis was only correlated with the increased number of lesions in the periventricular regions (p = 0.004). The level of intrathecal IgG synthesis was not correlated with any MRI data. CONCLUSION: The present longitudinal study demonstrates that the level of intrathecal IgM synthesis measured after a CIS is associated with subsequent lesion accrual during the first years of MS. This result emphasizes the involvement of IgM in plaque formation
Time-dependent and indirect effect of inorganic phosphate on force production in rat gastrocnemius exercising muscle determined by 31P-MRS
No full textAbstractThe relationship of inorganic phosphate (Pi) and its diprotonated form (H2PO4−) to isometric force (F) was analyzed non-invasively using 31P-magnetic resonance spectroscopy. Rat gastrocnemius muscles were electrically stimulated at six different frequencies in order to produce different levels of fatigue. A curvilinear relationship was demonstrated between force production and [Pi] and [H2PO4−] accumulation. [Pi] and [H2PO4−] were correlated with F at the end of the stimulation period but not when F was maximal at the early stage of the stimulation period. Interestingly, the respective [Pi] and [H2PO4−] did not differ significantly between these two stages demonstrating that [Pi] and [H2PO4−] cannot be considered as direct effectors of fatigue. This time-dependent and indirect effect of [Pi] and [H2PO4−] on force production might be mediated by calcium ions
Grid-free interactive and automated data processing for MR chemical shift imaging data
No full text0968-5243 (Print) 0968-5243 (Linking) Journal Article Research Support, Non-U.S. Gov'tPURPOSE: Today's available chemical shift imaging (CSI) analysis tools are based on Fourier transform of the entire data set prior to interactive display. This strategy is associated with limitations particularly when arbitrary voxel positions within a 3D spatial volume are needed by the user. In this work, we propose and demonstrate a processing-resource-efficient alternative strategy for both interactive and automated CSI data processing up to three spatial dimensions. METHODS: This approach uses real-time voxel-shift by first-order phase manipulation as a basis and therefore allows grid-free voxel positioning within the 3D volume. The corresponding spectrum is extracted from the 4D data (3D spatial/1D spectral) at each time a voxel position is selected. The spatial response function and hence the exact voxel size and shape are calculated in parallel including the same processing parameters. Using this mechanism sequentially along with AMARES time-domain modeling, we also implemented automated quantitative and B (0)-insensitive metabolite mapping. RESULTS: Metabolite maps of N-acetyl aspartate, choline and creatine were generated using (1)H-CSI data from the brain of healthy volunteers and patients with tumor and epilepsy. (31)P-3D-CSI of the heart of a healthy volunteer is also shown. CONCLUSION: The calculated metabolite maps demonstrate good stability and accuracy of the algorithm in all situations tested. The suggested algorithm constitutes therefore an attractive alternative to existing CSI processing strategies
Specificin vitro labeling of cells with a fluorine-19 probe encapsulated in antibody - targeted liposomes: A F-19 NMR spectroscopy study
No full textEvidencing different neurochemical profiles between thalamic nuclei using high resolution 2D-PRESS semi-LASER (1)H-MRSI at 7 T
No full textInternational audienceOBJECTIVE: To demonstrate that high resolution (1)H semi-LASER MRSI acquired at 7 T permits discrimination of metabolic patterns of different thalamic nuclei. MATERIALS AND METHODS: Thirteen right-handed healthy volunteers were explored at 7 T using a high-resolution 2D-semi-LASER (1)H-MRSI sequence to determine the relative levels of N-Acetyl Aspartate (NAA), choline (Cho) and creatine-phosphocreatine (Cr) in eight VOIs (volume \textless0.3 ml) centered on four different thalamic nuclei located on the Oxford thalamic connectivity atlas. Post-processing was done using the CSIAPO software. Chemical shift displacement of metabolites was evaluated on a phantom and correction factors were applied to in vivo data. RESULTS: The global assessment (ANOVA p \textless 0.05) of the neurochemical profiles (NAA, Cho and Cr levels) with thalamic nuclei and hemispheres as factors showed a significant global effect (F = 11.98, p \textless 0.0001), with significant effect of nucleus type (p \textless 0.0001) and hemisphere (p \textless 0.0001). Post hoc analyses showed differences in neurochemical profiles between the left and the right hemisphere (p \textless 0.05), and differences in neurochemical profiles between nuclei within each hemisphere (p \textless 0.05). CONCLUSION: For the first time, using high resolution 2D-PRESS semi-LASER (1)H-MRSI acquired at 7 T, we demonstrated that the neurochemical profiles were different between thalamic nuclei, and that these profiles were dependent on the brain hemisphere
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