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RANJEVA Marie-Pierre

MD PhD

mail@univ-amu.fr
tel : +33 4 91 38 ** **
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Current Research Interest and projects

Publications

2017

Journal Article

  • ALBI A., PASTERNAK O., MINATI L., MARIZZONI M., BARTRES-FAZ D., BARGALLO N., BOSCH B., ROSSINI P. M., MARRA C., MUELLER B., FIEDLER U., WILTFANG J., ROCCATAGLIATA L., PICCO A., NOBILI F. M., BLIN O., SEIN J., RANJEVA J. - P., DIDIC M., BOMBOIS S., LOPES R., BORDET R., GROS-DAGNAC H., PAYOUX P., ZOCCATELLI G., ALESSANDRINI F., BELTRAMELLO A., FERRETTI A., CAULO M., AIELLO M., CAVALIERE C., SORICELLI A., PARNETTI L., TARDUCCI R., FLORIDI P., TSOLAKI M., CONSTANTINIDIS M., DREVELEGAS A., FRISONI G., JOVICICH J. “Free water elimination improves test-retest reproducibility of diffusion tensor imaging indices in the brain: A longitudinal multisite study of healthy elderly subjects.”. Human Brain Mapping [En ligne]. 2017. Vol. 38, n°1, p. 12-26. Disponible sur : < http://dx.doi.org/10.1002/hbm.23350 > (consulté le no date)
    Résumé : Free water elimination (FWE) in brain diffusion MRI has been shown to improve tissue specificity in human white matter characterization both in health and in disease. Relative to the classical diffusion tensor imaging (DTI) model, FWE is also expected to increase sensitivity to microstructural changes in longitudinal studies. However, it is not clear if these two models differ in their test-retest reproducibility. This study compares a bi-tensor model for FWE with DTI by extending a previous longitudinal-reproducibility 3T multisite study (10 sites, 7 different scanner models) of 50 healthy elderly participants (55-80 years old) scanned in two sessions at least 1 week apart. We computed the reproducibility of commonly used DTI metrics (FA: fractional anisotropy, MD: mean diffusivity, RD: radial diffusivity, and AXD: axial diffusivity), derived either using a DTI model or a FWE model. The DTI metrics were evaluated over 48 white-matter regions of the JHU-ICBM-DTI-81 white-matter labels atlas, and reproducibility errors were assessed. We found that relative to the DTI model, FWE significantly reduced reproducibility errors in most areas tested. In particular, for the FA and MD metrics, there was an average reduction of approximately 1% in the reproducibility error. The reproducibility scores did not significantly differ across sites. This study shows that FWE improves sensitivity and is thus promising for clinical applications, with the potential to identify more subtle changes. The increased reproducibility allows for smaller sample size or shorter trials in studies evaluating biomarkers of disease progression or treatment effects. Hum Brain Mapp 38:12-26, 2017. (c) 2016 Wiley Periodicals, Inc.
    Mots-clés : alzheimers-disease, brain diffusion tensor imaging, cerebral white-matter, false discovery rate, free-water imaging, healthy elderly, longitudinal, MRI, multisite diffusion MRI, parkinsons-disease, reliability, Schizophrenia, spatial statistics, substantia-nigra, test-retest reproducibility, tracking.

  • AZIZ A. - L., GIUSIANO B., JOUBERT S., DUPRAT L., DIDIC M., GUERIOT C., KORIC L., BOUCRAUT J., FELICIAN O., RANJEVA J. - P., GUEDJ E., CECCALDI M. “Difference in imaging biomarkers of neurodegeneration between early and late-onset amnestic Alzheimer's disease.”. Neurobiology of Aging [En ligne]. 2017. Vol. 54, p. 22-30. Disponible sur : < http://dx.doi.org/10.1016/j.neurobiolaging.2017.02.010 > (consulté le no date)
    Résumé : Neuroimaging biomarkers differ between patients with early-onset Alzheimer's disease (EOAD) and late-onset Alzheimer's disease (LOAD). Whether these changes reflect cognitive heterogeneity or differences in disease severity is still unknown. This study aimed at investigating changes in neuroimaging biomarkers, according to the age of onset of the disease, in mild amnestic Alzheimer's disease patients with positive amyloid biomarkers in cerebrospinal fluid. Both patient groups were impaired on tasks assessing verbal and visual recognition memory. EOAD patients showed greater executive and linguistic deficits, while LOAD patients showed greater semantic memory impairment. In EOAD and LOAD, hypometabolism involved the bilateral temporoparietal junction and the posterior cingulate cortex. In EOAD, atrophy was widespread, including frontotemporoparietal areas, whereas it was limited to temporal regions in LOAD. Atrophic volumes were greater in EOAD than in LOAD. Hypometabolic volumes were similar in the 2 groups. Greater extent of atrophy in EOAD, despite similar extent of hypometabolism, could reflect different underlying pathophysiological processes, different glucose-based compensatory mechanisms or distinct level of premorbid atrophic lesions.
    Mots-clés : Age of Onset, Alzheimer's disease, Magnetic Resonance Imaging, Neuroimaging biomarkers, Positron emission tomography imaging.


  • BESSON P., CARRIÈRE N., BANDT S. K., TOMMASI M., LECLERC X., DERAMBURE P., LOPES R., TYVAERT L. “Whole-Brain High-Resolution Structural Connectome: Inter-Subject Validation and Application to the Anatomical Segmentation of the Striatum.”. Brain Topography [En ligne]. 2017. Vol. 30, n°3, p. 291-302. Disponible sur : < http://dx.doi.org/10.1007/s10548-017-0548-0 >
    Résumé : The present study describes extraction of high-resolution structural connectome (HRSC) in 99 healthy subjects, acquired and made available by the Human Connectome Project. Single subject connectomes were then registered to the common surface space to allow assessment of inter-individual reproducibility of this novel technique using a leave-one-out approach. The anatomic relevance of the surface-based connectome was examined via a clustering algorithm, which identified anatomic subdivisions within the striatum. The connectivity of these striatal subdivisions were then mapped on the cortical and other subcortical surfaces. Findings demonstrate that HRSC analysis is robust across individuals and accurately models the actual underlying brain networks related to the striatum. This suggests that this method has the potential to model and characterize the healthy whole-brain structural network at high anatomic resolution.
    Mots-clés : Connectome, Diffusion Magnetic Resonance Imaging, High-resolution, Striatum clustering, Surface-based connectivity.

  • BYDDER M., RAPACCHI S., GIRARD O., GUYE M., RANJEVA J. - P. “Trimmed autocalibrating k-space estimation based on structured matrix completion.”. Magnetic Resonance Imaging [En ligne]. 2017. Vol. 43, p. 88-94. Disponible sur : < http://dx.doi.org/10.1016/j.mri.2017.07.015 > (consulté le no date)
    Résumé : PURPOSE: Parallel imaging allows the reconstruction of undersampled data from multiple coils. This provides a means to reject and regenerate corrupt data (e.g. from motion artefact). The purpose of this work is to approach this problem using the SAKE parallel imaging method. THEORY AND METHODS: Parallel imaging methods typically require calibration by fully sampling the center of k-space. This is a challenge in the presence of corrupted data, since the calibration data may be corrupted which leads to an errors-in-variables problem that cannot be solved by least squares or even iteratively reweighted least squares. The SAKE method, based on matrix completion and structured low rank approximation, was modified to detect and trim these errors from the data. RESULTS: Simulated and actual corrupted datasets were reconstructed with SAKE, the proposed approach and a more standard reconstruction method (based on solving a linear equation) with a data rejection criterion. The proposed approach was found to reduce artefacts considerably in comparison to the other two methods. CONCLUSION: SAKE with data trimming improves on previous methods for reconstructing images from grossly corrupted data.
    Mots-clés : Artefacts, crmbm, IRLS, Parallel imaging, Robust, Structured low rank approximation.

  • CHATEL B., HOURDé C., GONDIN J., FOURé A., LE FUR Y., VILMEN C., BERNARD M., MESSONNIER L. A., BENDAHAN D. “Impaired muscle force production and higher fatigability in a mouse model of sickle cell disease.”. Blood Cells, Molecules & Diseases [En ligne]. 2017. Vol. 63, p. 37-44. Disponible sur : < http://dx.doi.org/10.1016/j.bcmd.2017.01.004 > (consulté le no date)
    Résumé : Skeletal muscle function has been scarcely investigated in sickle cell disease (SCD) so that the corresponding impact of sickle hemoglobin is still a matter of debate. The purpose of this study was to investigate muscle force production and fatigability in SCD and to identify whether exercise intensity could have a modulatory effect. Ten homozygous sickle cell (HbSS), ten control (HbAA) and ten heterozygous (HbAS) mice were submitted to two stimulation protocols (moderate and intense) to assess force production and fatigability. We showed that specific maximal tetanic force was lower in HbSS mice as compared to other groups. At the onset of the stimulation period, peak force was reduced in HbSS and HbAS mice as compared to HbAA mice. Contrary to the moderate protocol, the intense stimulation protocol was associated with a larger decrease in peak force and rate of force development in HbSS mice as compared to HbAA and HbAS mice. These findings provide in vivo evidence of impaired muscle force production and resistance to fatigue in SCD. These changes are independent of muscle mass. Moreover, SCD is associated with muscle fatigability when exercise intensity is high.
    Mots-clés : crmbm, Exercise intensity, Muscle mass, Muscle volume, Rate of force development.


  • CHATEL B., MESSONNIER L. A., BENDAHAN D. “Exacerbated in vivo metabolic changes suggestive of a spontaneous muscular vaso-occlusive crisis in exercising muscle of a sickle cell mouse.”. Blood Cells, Molecules, and Diseases [En ligne]. 2017. Vol. 65, p. 56-59. Disponible sur : < http://dx.doi.org/10.1016/j.bcmd.2017.05.006 >
    Résumé : While sickle cell disease (SCD) is characterized by frequent vaso-occlusive crisis (VOC), no direct observation of such an event in skeletal muscle has been performed in vivo. The present study reported exacerbated in vivo metabolic changes suggestive of a spontaneous muscular VOC in exercising muscle of a sickle cell mouse. Using magnetic resonance spectroscopy of phosphorus 31, phosphocreatine and inorganic phosphate concentrations and intramuscular pH were measured throughout two standardized protocols of rest – exercise – recovery at two different intensities in ten SCD mice. Among these mice, one single mouse presented divergent responses. A statistical analysis (based on confidence intervals) revealed that this single mouse presented slower phosphocreatine resynthesis and inorganic phosphate disappearance during the post-stimulation recovery of one of the protocols, what could suggest an ischemia. This study described, for the first time in a sickle cell mouse in vivo, exacerbated metabolic changes triggered by an exercise session that would be suggestive of a live observation of a muscular VOC. However, no evidence of a direct cause-effect relationship between exercise and VOC has been put forth.
    Mots-clés : crmbm, HbS polymerization, Magnetic resonance spectroscopy of phosphorus 31, Physical activity, Red blood cell sickling.

  • DE LEENER B., LEVY S., DUPONT S. M., FONOV V. S., STIKOV N., COLLINS D. L., CALLOT V., COHEN-ADAD J. “SCT: Spinal Cord Toolbox, an open-source software for processing spinal cord MRI data.”. Neuroimage [En ligne]. 2017. Vol. 145, p. 24-43. Disponible sur : < http://dx.doi.org/10.1016/j.neuroimage.2016.10.009 > (consulté le no date)
    Résumé : For the past 25 years, the field of neuroimaging has witnessed the development of several software packages for processing multi-parametric magnetic resonance imaging (mpMRI) to study the brain. These software packages are now routinely used by researchers and clinicians, and have contributed to important breakthroughs for the understanding of brain anatomy and function. However, no software package exists to process mpMRI data of the spinal cord. Despite the numerous clinical needs for such advanced mpMRI protocols (multiple sclerosis, spinal cord injury, cervical spondylotic myelopathy, etc.), researchers have been developing specific tools that, while necessary, do not provide an integrative framework that is compatible with most usages and that is capable of reaching the community at large. This hinders cross-validation and the possibility to perform multi-center studies. In this study we introduce the Spinal Cord Toolbox (SCT), a comprehensive software dedicated to the processing of spinal cord MRI data. SCT builds on previously-validated methods and includes state-of-the-art MM templates and atlases of the spinal cord, algorithms to segment and register new data to the templates, and motion correction methods for diffusion and functional time series. SCT is tailored towards standardization and automation of the processing pipeline, versatility, modularity, and it follows guidelines of software development and distribution. Preliminary applications of SCT cover a variety of studies, from cross-sectional area measures in large databases of patients, to the precise quantification of mpMRI metrics in specific spinal pathways. We anticipate that SCT will bring together the spinal cord neuroimaging community by establishing standard templates and analysis procedures.
    Mots-clés : 3 tesla, age, Atlas, automatic segmentation, Brain, diffeomorphic image registration, In-vivo, magnetization-transfer, matter segmentation, MRI, multiple-sclerosis, of-the-art, open-source, Software, spinal cord, Template.

  • DE LEENER B., MANGEAT G., DUPONT S., MARTIN A. R., CALLOT V., STIKOV N., FEHLINGS M. G., COHEN-ADAD J. “Topologically preserving straightening of spinal cord MRI.”. Journal of magnetic resonance imaging: JMRI [En ligne]. 2017. Disponible sur : < http://dx.doi.org/10.1002/jmri.25622 > (consulté le no date)
    Résumé : PURPOSE: To propose a robust and accurate method for straightening magnetic resonance (MR) images of the spinal cord, based on spinal cord segmentation, that preserves spinal cord topology and that works for any MRI contrast, in a context of spinal cord template-based analysis. MATERIALS AND METHODS: The spinal cord curvature was computed using an iterative Non-Uniform Rational B-Spline (NURBS) approximation. Forward and inverse deformation fields for straightening were computed by solving analytically the straightening equations for each image voxel. Computational speed-up was accomplished by solving all voxel equation systems as one single system. Straightening accuracy (mean and maximum distance from straight line), computational time, and robustness to spinal cord length was evaluated using the proposed and the standard straightening method (label-based spline deformation) on 3T T2 - and T1 -weighted images from 57 healthy subjects and 33 patients with spinal cord compression due to degenerative cervical myelopathy (DCM). RESULTS: The proposed algorithm was more accurate, more robust, and faster than the standard method (mean distance = 0.80 vs. 0.83 mm, maximum distance = 1.49 vs. 1.78 mm, time = 71 vs. 174 sec for the healthy population and mean distance = 0.65 vs. 0.68 mm, maximum distance = 1.28 vs. 1.55 mm, time = 32 vs. 60 sec for the DCM population). CONCLUSION: A novel image straightening method that enables template-based analysis of quantitative spinal cord MRI data is introduced. This algorithm works for any MRI contrast and was validated on healthy and patient populations. The presented method is implemented in the Spinal Cord Toolbox, an open-source software for processing spinal cord MRI data. LEVEL OF EVIDENCE: 1. J. Magn. Reson. Imaging 2017.
    Mots-clés : deformation field, MR image analysis, NURBS, SCT, spinal cord, straightening.

  • DESROIS M., LAN C., MOVASSAT J., BERNARD M. “Reduced up-regulation of the nitric oxide pathway and impaired endothelial and smooth muscle functions in the female type 2 diabetic goto-kakizaki rat heart.”. Nutrition & Metabolism [En ligne]. 2017. Vol. 14, p. 6. Disponible sur : < http://dx.doi.org/10.1186/s12986-016-0157-z > (consulté le no date)
    Résumé : BACKGROUND: Type 2 diabetes is associated with greater relative risk of cardiovascular diseases in women than in men, which is not well understood. Consequently, we have investigated if male and female displayed differences in cardiac function, energy metabolism, and endothelial function which could contribute to increased cardiovascular complications in type 2 diabetic female. METHODS: Male and female Control and type 2 diabetic Goto-Kakizaki (GK) isolated rat hearts were perfused during 28 min with a physiological buffer before freeze-clamping for biochemical assays. High energy phosphate compounds and intracellular pH were followed using (31)P magnetic resonance spectroscopy with simultaneous measurement of contractile function. Nitric oxide (NO) pathway and endothelium-dependent and independent vasodilatations were measured as indexes of endothelial function. Results were analyzed via two-way ANOVA, p < 0.05 was considered as statistically significant. RESULTS: Myocardial function was impaired in male and female diabetic versus Control groups (p < 0.05) without modification of energy metabolism. Coronary flow was decreased in both diabetic versus Control groups but to a higher extent in female GK versus male GK rat hearts (p < 0.05). NO production was up-regulated in diabetic groups but to a less extent in female GK rat hearts (p < 0.05). Endothelium-dependent and independent vasodilatations were impaired in female GK rat compared with male GK (p < 0.05) and female Control (p < 0.05) rat hearts. CONCLUSIONS: We reported here an endothelial damage characterized by a reduced up-regulation of the NO pathway and impaired endothelial and smooth muscle functions, and coronary flow rates in the female GK rat hearts while energy metabolism was normal. Whether these results are related to the higher risk of cardiovascular complications among type 2 diabetic female needs to be further elicited in the future.
    Mots-clés : Cardiac function, crmbm, Endothelial function, Energy Metabolism, Gender differences, Type 2 diabetic heart.

  • FISSOLO N., PIGNOLET B., MATUTE-BLANCH C., TRIVIÑO J. C., MIRÓ B., MOTA M., PEREZ-HOYOS S., SANCHEZ A., VERMERSCH P., RUET A., DE SÈZE J., LABAUGE P., VUKUSIC S., PAPEIX C., ALMOYNA L., TOURBAH A., CLAVELOU P., MOREAU T., PELLETIER J., LEBRUN-FRENAY C., MONTALBAN X., BRASSAT D., COMABELLA M., BIONAT, BEST-MS AND SFSEP NETWORK. “MMP9 is decreased in natalizumab-treated MS patients at risk for PML.”. Annals of Neurology [En ligne]. 2017. Disponible sur : < http://dx.doi.org/10.1002/ana.24987 > (consulté le no date)
    Résumé : OBJECTIVE: To identify biomarkers associated with the development of progressive multifocal leukoencephalopathy (PML) in multiple sclerosis (MS) patients treated with natalizumab (NTZ). METHODS: Relapsing-remitting MS (RRMS) patients who developed PML under NTZ therapy (pre-PML) and non-PML natalizumab-treated patients (NTZ-ctr) were included in the study. Cryopreserved peripheral blood mononuclear cells (PBMC) and serum samples collected at baseline, at one- and two-year treated time points, and during PML were analyzed for gene expression by RNA-sequencing and for serum protein levels by LUMINEX and ELISA assays respectively. RESULTS: Among top differentially expressed genes in the RNA-sequencing between pre-PML and NTZ-ctr patients, pathway analysis revealed a high representation of genes belonging to the following categories: pro-angiogenic factors (MMP9, VEGFA), chemokines (CXCL1, CXCL5, IL8, CCL2), cytokines (IL1B, IFNG), and plasminogen- and coagulation-related molecules (SERPINB2, PLAU, PLAUR, TFPI, THBD). Serum protein levels for these candidates were measured in a two-step manner in a screening cohort and a validation cohort of pre-PML and NTZ-ctr patients. Only MMP9 was validated and, in pre-PML patients MMP9 protein levels were significantly reduced at baseline compared with NTZ-ctr patients and levels remained lower at later time points during NTZ treatment. INTERPRETATION: The results from this study suggest that the pro-angiogenic factor MMP9 may play a role as biomarker associated with the development of PML in MS patients treated with NTZ. This article is protected by copyright. All rights reserved.

  • FOURÉ A., BENDAHAN D. “Is Branched-Chain Amino Acids Supplementation an Efficient Nutritional Strategy to Alleviate Skeletal Muscle Damage? A Systematic Review.”. Nutrients [En ligne]. 2017. Vol. 9, n°10,. Disponible sur : < http://dx.doi.org/10.3390/nu9101047 > (consulté le no date)
    Résumé : Amino acids and more precisely, branched-chain amino acids (BCAAs), are usually consumed as nutritional supplements by many athletes and people involved in regular and moderate physical activities regardless of their practice level. BCAAs have been initially shown to increase muscle mass and have also been implicated in the limitation of structural and metabolic alterations associated with exercise damage. This systematic review provides a comprehensive analysis of the literature regarding the beneficial effects of BCAAs supplementation within the context of exercise-induced muscle damage or muscle injury. The potential benefit of a BCAAs supplementation was also analyzed according to the supplementation strategy-amount of BCAAs, frequency and duration of the supplementation-and the extent of muscle damage. The review protocol was registered prospectively with Prospective Register for Systematic Reviews (registration number CRD42017073006) and followed Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. Literature search was performed from the date of commencement until August 2017 using four online databases (Medline, Cochrane library, Web of science and ScienceDirect). Original research articles: (i) written in English; (ii) describing experiments performed in Humans who received at least one oral BCAAs supplementation composed of leucine, isoleucine and valine mixture only as a nutritional strategy and (iii) reporting a follow-up of at least one day after exercise-induced muscle damage, were included in the systematic review analysis. Quality assessment was undertaken independently using the Quality Criteria Checklist for Primary Research. Changes in indirect markers of muscle damage were considered as primary outcome measures. Secondary outcome measures were the extent of change in indirect markers of muscle damage. In total, 11 studies were included in the analysis. A high heterogeneity was found regarding the different outcomes of these studies. The risk of bias was moderate considering the quality ratings were positive for six and neutral for three. Although a small number of studies were included, BCAAs supplementation can be efficacious on outcomes of exercise-induced muscle damage, as long as the extent of muscle damage was low-to-moderate, the supplementation strategy combined a high daily BCAAs intake (>200 mg kg(-1) day(-1)) for a long period of time (>10 days); it was especially effective if taken prior to the damaging exercise.
    Mots-clés : branched-chain amino acids (BCAAs), crmbm, exercise-induced muscle damage, nutritional strategy, skeletal muscle.

  • FOURÉ A., DUHAMEL G., VILMEN C., BENDAHAN D., JUBEAU M., GONDIN J. “Fast measurement of the quadriceps femoris muscle transverse relaxation time at high magnetic field using segmented echo-planar imaging.”. Journal of magnetic resonance imaging: JMRI [En ligne]. 2017. Vol. 45, n°2, p. 356-368. Disponible sur : < http://dx.doi.org/10.1002/jmri.25355 > (consulté le no date)
    Résumé : PURPOSE: To assess and validate a technique for transverse relaxation time (T2 ) measurements of resting and recovering skeletal muscle following exercise with a high temporal resolution and large volume coverage using segmented spin-echo echo-planar imaging (sSE-EPI). MATERIALS AND METHODS: Experiments were performed on a 3T magnetic resonance imaging (MRI) scanner using a multislice sSE-EPI technique applied at different echo times (TEs). T2 measurements were first validated in vitro in calibrated T2 phantoms (range: 25-152 ms) by comparing sSE-EPI, standard spin-echo (SE), and multislice multiecho (MSME) techniques (using a fitting procedure or a 2-TEs calculation). In vivo measurements of resting T2 quadriceps femoris (QF) muscle were performed with both sSE-EPI and MSME sequences. Finally, sSE-EPI was used to quantify T2 changes in recovering muscle after an exercise. RESULTS: T2 values measured in vitro with sSE-EPI were similar to those assessed with SE (P > 0.05). In vitro and in vivo T2 measurements obtained with sSE-EPI were independent of the T2 determination procedure (P > 0.05). In contrast, both in vitro and in vivo T2 values derived from MSME were significantly different when using 2-TEs calculation as compared to the fitting procedure (P < 0.05). sSE-EPI allowed the detection of increased T2 values in the QF muscle immediately after exercise (+14 ± 9%), while lower T2 values were recorded less than 2 min afterwards (P < 0.05). CONCLUSION: sSE-EPI sequence is a relevant method to monitor exercise-induced T2 changes of skeletal muscles over large volume coverage and to detect abnormal patterns of muscle activation. LEVEL OF EVIDENCE: 1 J. Magn. Reson. Imaging 2017;45:356-368.
    Mots-clés : crmbm, Exercise, MRI, skeletal muscle, spin-echo sequence, T2.

  • FOURNELY M., PETIT Y., WAGNAC É., LAURIN J., CALLOT V., ARNOUX P. - J. “High-speed video analysis improves the accuracy of spinal cord compression measurement in a mouse contusion model.”. Journal of Neuroscience Methods [En ligne]. 2017. Disponible sur : < http://dx.doi.org/10.1016/j.jneumeth.2017.09.007 > (consulté le no date)
    Résumé : BACKGROUND: Animal models of spinal cord injuries aim to utilize controlled and reproducible conditions. However, a literature review reveals that mouse contusion studies using equivalent protocols may show large disparities in the observed impact force vs. cord compression relationship. The overall purpose of this study was to investigate possible sources of bias in these measurements. The specific objective was to improve spinal cord compression measurements using a video-based setup to detect the impactor-spinal cord time-to-contact. NEW METHOD: A force-controlled 30kDyn unilateral contusion at C4 vertebral level was performed in six mice with the Infinite Horizon impactor (IH). High-speed video was used to determine the time-to-contact between the impactor tip and the spinal cord and to compute the related displacement of the tip into the tissue: the spinal cord compression and the compression ratio. RESULTS & COMPARISON WITH EXISTING METHOD(S): Delayed time-to-contact detection with the IH device led to an underestimation of the cord compression. Compression values indicated by the IH were 64% lower than those based on video analysis (0.33mm vs. 0.88mm). Consequently, the mean compression ratio derived from the device was underestimated when compared to the value derived from video analysis (22% vs. 61%). CONCLUSIONS: Default time-to-contact detection from the IH led to significant errors in spinal cord compression assessment. Accordingly, this may explain some of the reported data discrepancies in the literature. The proposed setup could be implemented by users of contusion devices to improve the quantative description of the primary injury inflicted to the spinal cord.
    Mots-clés : Compression ratio, Contusion device, High-speed video analysis, Mouse model, Spinal cord injury.

  • GABORIT B., SENGENES C., ANCEL P., JACQUIER A., DUTOUR A. “Role of Epicardial Adipose Tissue in Health and Disease: A Matter of Fat?”. Comprehensive Physiology [En ligne]. 2017. Vol. 7, n°3, p. 1051-1082. Disponible sur : < http://dx.doi.org/10.1002/cphy.c160034 > (consulté le no date)
    Résumé : Epicardial adipose tissue (EAT) is a small but very biologically active ectopic fat depot that surrounds the heart. Given its rapid metabolism, thermogenic capacity, unique transcriptome, secretory profile, and simply measurability, epicardial fat has drawn increasing attention among researchers attempting to elucidate its putative role in health and cardiovascular diseases. The cellular crosstalk between epicardial adipocytes and cells of the vascular wall or myocytes is high and suggests a local role for this tissue. The balance between protective and proinflammatory/profibrotic cytokines, chemokines, and adipokines released by EAT seem to be a key element in atherogenesis and could represent a future therapeutic target. EAT amount has been found to predict clinical coronary outcomes. EAT can also modulate cardiac structure and function. Its amount has been associated with atrial fibrillation, coronary artery disease, and sleep apnea syndrome. Conversely, a beiging fat profile of EAT has been identified. In this review, we describe the current state of knowledge regarding the anatomy, physiology and pathophysiological role of EAT, and the factors more globally leading to ectopic fat development. We will also highlight the most recent findings on the origin of this ectopic tissue, and its association with cardiac diseases. © 2017 American Physiological Society. Compr Physiol 7:1051-1082, 2017.


  • GIRARD O. M., CALLOT V., PREVOST V. H., ROBERT B., TASO M., RIBEIRO G., VARMA G., RANGWALA N., ALSOP D. C., DUHAMEL G. “Magnetization transfer from inhomogeneously broadened lines (ihMT): Improved imaging strategy for spinal cord applications.”. Magnetic Resonance in Medicine [En ligne]. 2017. Vol. 77, p. 581-591. Disponible sur : < http://dx.doi.org/10.1002/mrm.26134 >
    Résumé : Purpose Inhomogeneous magnetization transfer (ihMT) shows great promise for specific imaging of myelinated tissues. Whereas the ihMT technique has been previously applied in brain applications, the current report presents a strategy for cervical spinal cord (SC) imaging free of cerebrospinal fluid (CSF) pulsatility artifacts. Methods A pulsed ihMT preparation was combined with a single-shot HASTE readout. Electrocardiogram (ECG) synchronization was used to acquire all images during the quiescent phase of SC motion. However ihMT signal quantification errors may occur when a variable recovery delay is introduced in the sequence as a consequence of variable cardiac cycle. A semiautomatic retrospective correction algorithm, based on repetition time (TR) -matching, is proposed to correct for signal variations of long T1-components (e.g., CSF). Results The proposed strategy combining ECG synchronization and retrospective data pairing led to clean SC images free of CSF artifacts. Lower variability of the ihMT metrics were obtained with the correction algorithm, and allowed for shorter TR to be used, hence improving signal-to-noise ratio efficiency. Conclusion The proposed methodology enabled faster acquisitions, while offering robust ihMT quantification and exquisite SC image quality. This opens great perspectives for widening the in vivo characterization of SC physiopathology using MRI, such as studying white matter tracts microstructure or impairment in degenerative pathologies. Magn Reson Med, 2016. © 2016 Wiley Periodicals, Inc.
    Mots-clés : crmbm, CSF pulsatility, ECG synchronization, ihMT, inhomogeneous magnetization transfer, motion correction, myelin, spinal cord, white matter.

  • GRIMALDI S., DUPRAT L., GRAPPERON A. - M., VERSCHUEREN A., DELMONT E., ATTARIAN S. “Global Motor Unit Number Index sum score for assessing the loss of lower motor neurons in amyotrophic lateral sclerosis.”. Muscle & Nerve [En ligne]. 2017. Disponible sur : < http://dx.doi.org/10.1002/mus.25595 > (consulté le no date)
    Résumé : Introduction Our objective was to propose a motor unit number index (MUNIX) global sum score in amyotrophic lateral sclerosis (ALS) to estimate the loss of functional motor units. Methods MUNIX was assessed for 18 ALS patients and 17 healthy controls in seven muscles: the abductor pollicis brevis (APB), abductor digiti minimi (ADM), tibialis anterior (TA), deltoid, trapezius, submental complex (SMC) and orbicularis oris. Results MUNIX was significantly lower in ALS patients than in healthy controls for the APB, ADM, TA and the trapezius muscles. The MUNIX sum score of 4 muscles (ADM + APB + Trapezius + TA) was lower in ALS patients (P = 0.01) and was correlated with clinical scores. Discussion The global MUNIX sum score proposed in this study estimates the loss of lower motor neurons in several body regions including the trapezius, and is correlated with clinical impairment in ALS patients. This article is protected by copyright. All rights reserved.
    Mots-clés : ALS, biomarker, clinical correlation, global MUNIX sum score, motor unit, MUNIX.

  • GUENOUN D., FOURÉ A., PITHIOUX M., GUIS S., LE CORROLLER T., MATTEI J. - P., PAULY V., GUYE M., BERNARD M., CHABRAND P., CHAMPSAUR P., BENDAHAN D. “Correlative Analysis Of Vertebral Trabecular Bone Microarchitecture and Mechanical Properties: A Combined Ultra-High Field (7 Tesla) MRI and Biomechanical Investigation.”. Spine [En ligne]. 2017. Disponible sur : < http://dx.doi.org/10.1097/BRS.0000000000002163 > (consulté le no date)
    Résumé : STUDY DESIGN: High resolution imaging and biomechanical investigation of ex-vivo vertebrae OBJECTIVE.: To assess bone microarchitecture of cadaveric vertebrae using ultra-high field (UHF) 7 Tesla magnetic resonance imaging (MRI) and to determine whether the corresponding microarchitecture parameters were related to BMD and bone strength assessed by dual energy X-ray absorptiometry (DXA) and mechanical compression tests. SUMMARY OF BACKGROUND DATA: Limitations of DXA for the assessment of bone fragility and osteoporosis have been recognized and criteria of microarchitecture alteration have been included in the definition of osteoporosis. Although vertebral fracture is the most common osteoporotic fracture, no study has assessed directly vertebral trabecular bone. microarchitecture. METHODS: BMD of twenty four vertebrae (L2, L3, L4) from eight cadavers were investigated using DXA. The bone volume fraction (BVF), trabecular thickness (Tb.Th), and trabecular spacing (Tb.Sp) of each vertebra was quantified using UHF MRI. Measurements were performed by two operators in order to characterize the inter-rater reliability. The whole set of specimens underwent mechanical compression tests to failure and the corresponding failure stress was calculated. RESULTS: The inter-rater reliability for bone microarchitecture parameters was good withintraclass correlation coefficients ranging from 0.82 to 0.94. Failure load and stress were significantly correlated with BVF, Tb.Sp and BMD (p < 0.05). Tb.Th was only correlated with the failure stress (p < 0.05). Multiple regression analysis demonstrated that the combination of BVF and BMD improved the prediction of the failure stress from an adjustedR = 0.384 for BMD alone to an adjusted R = 0.414. CONCLUSIONS: We demonstrated for the first time that the vertebral bone microarchitecture assessed with UHF MRI was significantly correlated with biomechanical parameters. Our data suggest that the multimodal assessment of BMD and trabecular bone microarchitecture with UHF MRI provides additional information on the risk of vertebral bone fracture and might be of interest for the future investigation of selected osteoporotic patients. LEVEL OF EVIDENCE: N/A.

  • HABIB G., BUCCIARELLI-DUCCI C., CAFORIO A. L. P., CARDIM N., CHARRON P., COSYNS B., DEHAENE A., DERUMEAUX G., DONAL E., DWECK M. R., EDVARDSEN T., ERBA P. A., ERNANDE L., GAEMPERLI O., GALDERISI M., GRAPSA J., JACQUIER A., KLINGEL K., LANCELLOTTI P., NEGLIA D., PEPE A., PERRONE-FILARDI P., PETERSEN S. E., PLEIN S., POPESCU B. A., REANT P., SADE L. E., SALAUN E., SLART R. H. J. A., TRIBOUILLOY C., ZAMORANO J., REVIEWERS: VICTORIA DELGADO, KRISTINA HAUGAA (EACVI SCIENTIFIC DOCUMENTS COMMITTEE) AND G VIJAYARAGHAVAN (INDIAN ACADEMY OF ECHOCARDIOGRAPHY). “Multimodality imaging in restrictive cardiomyopathies: an EACVI expert consensus document: In collaboration with the 'Working Group on myocardial and pericardial diseases' of the European Society of Cardiology Endorsed by the Indian Academy of Echocardiography.”. European Heart Journal Cardiovascular Imaging [En ligne]. 2017. Disponible sur : < http://dx.doi.org/10.1093/ehjci/jex034 > (consulté le no date)
    Résumé : Restrictive cardiomyopathies (RCMs) are a diverse group of myocardial diseases with a wide range of aetiologies, including familial, genetic and acquired diseases and ranging from very rare to relatively frequent cardiac disorders. In all these diseases, imaging techniques play a central role. Advanced imaging techniques provide important novel data on the diagnostic and prognostic assessment of RCMs. This EACVI consensus document provides comprehensive information for the appropriateness of all non-invasive imaging techniques for the diagnosis, prognostic evaluation, and management of patients with RCM.
    Mots-clés : cardiac magnetic resonance, Cardiomyopathies, Computed tomography, Echocardiography, nuclear imaging, restrictive cardiomyopathies.

  • HAN F., RAPACCHI S., HU P. “Prospective cardiac motion self-gating.”. Quantitative Imaging in Medicine and Surgery [En ligne]. 2017. Vol. 7, n°2, p. 215-226. Disponible sur : < http://dx.doi.org/10.21037/qims.2017.03.02 > (consulté le no date)
    Résumé : BACKGROUND: To develop a prospective cardiac motion self-gating method that provides robust and accurate cardiac triggers in real time. METHODS: The proposed self-gating method consists of an "imaging mode" that acquires the k-space segments and a "self-gating mode" that captures the cardiac motion by repeatedly sampling the k-space centerline. A training based principal component analysis algorithm is utilized to process the self-gating data where the projection onto the first principal component was used as the self-gating signal. Retrospective studies using a sequence with self-gating mode only was performed on 8 healthy subjects to validate the accuracy and reliability of the self-gating triggers. Prospective studies using both ECG-gated and self-gated cardiac CINE sequences were conducted on 6 healthy subjects to compare the image quality. RESULTS: Using the ECG as the reference, the proposed method was able to detect self-gating triggers within ±10 ms accuracy on all 8 subjects in the retrospective study. The prospectively self-gated CINE sequence successfully detected 100% of the cardiac triggers and provided excellent CINE image quality without using ECG signals. CONCLUSIONS: The proposed cardiac self-gating method is a robust and accurate alternative to conventional ECG-based gating method for a number of cardiac MRI applications.
    Mots-clés : cardiac MRI, motion correction using multiple coil array (MOCCA), principal component analysis (PCA), prospective gating, Self-gating.

  • JIRSA V. K., PROIX T., PERDIKIS D., WOODMAN M. M., WANG H., GONZALEZ-MARTINEZ J., BERNARD C., BENAR C., GUYE M., CHAUVEL P., BARTOLOMEI F. “The Virtual Epileptic Patient: Individualized whole-brain models of epilepsy spread.”. Neuroimage [En ligne]. 2017. Vol. 145, p. 377-388. Disponible sur : < http://dx.doi.org/10.1016/j.neuroimage.2016.04.049 > (consulté le no date)
    Résumé : Individual variability has clear effects upon the outcome of therapies and treatment approaches. The customization of healthcare options to the individual patient should accordingly improve treatment results. We propose a novel approach to brain interventions based on personalized brain network models derived from non-invasive structural data of individual patients. Along the example of a patient with bitemporal epilepsy, we show step by step how to develop a Virtual Epileptic Patient (VEP) brain model and integrate patient-specific information such as brain connectivity, epileptogenic zone and MRI lesions. Using high-performance computing, we systematically carry out parameter space explorations, fit and validate the brain model against the patient's empirical stereotactic EEG (SEEG) data and demonstrate how to develop novel personalized strategies towards therapy and intervention. (C) 2016 The Authors. Published by Elsevier Inc.
    Mots-clés : Diffusion MRI, eeg, Functional connectivity, network dynamics, resting brain, spherical-deconvolution, Structural connectivity, surgery, temporal-lobe epilepsy, tractography.

  • LAROCHE M., ALMERAS L., PECCHI E., BECHAH Y., RAOULT D., VIOLA A., PAROLA P. “MALDI-TOF MS as an innovative tool for detection of Plasmodium parasites in Anopheles mosquitoes.”. Malaria Journal [En ligne]. 2017. Vol. 16, n°1, p. 5. Disponible sur : < http://dx.doi.org/10.1186/s12936-016-1657-z > (consulté le no date)
    Résumé : BACKGROUND: Malaria is still a major public health issue worldwide, and one of the best approaches to fight the disease remains vector control. The current methods for mosquito identification include morphological methods that are generally time-consuming and require expertise, and molecular methods that require laboratory facilities with relatively expensive running costs. Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) technology, routinely used for bacterial identification, has recently emerged in the field of entomology. The aim of the present study was to assess whether MALDI-TOF MS could successfully distinguish Anopheles stephensi mosquitoes according to their Plasmodium infection status. METHODS: C57BL/6 mice experimentally infected with Plasmodium berghei were exposed to An. stephensi bites. For the determination of An. stephensi infection status, mosquito cephalothoraxes were dissected and submitted to mass spectrometry analyses and DNA amplification for molecular analysis. Spectra were grouped according to mosquitoes' infection status and spectra quality was validated based on intensity and reproducibility within each group. The in-lab MALDI-TOF MS arthropod reference spectra database, upgraded with representative spectra from both groups (infected/non-infected), was subsequently queried blindly with cephalothorax spectra from specimens of both groups. RESULTS: The MALDI TOF MS profiles generated from protein extracts prepared from the cephalothorax of An. stephensi allowed distinction between infected and uninfected mosquitoes. Correct classification was obtained in blind test analysis for (79/80) 98.75% of all mosquitoes tested. Only one of 80 specimens, an infected mosquito, was misclassified in the blind test analysis. CONCLUSIONS: Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry appears to be a promising, rapid and reliable tool for the epidemiological surveillance of Anopheles vectors, including their identification and their infection status.
    Mots-clés : crmbm.


  • LEPORQ B., TROTER A. L., FUR Y. L., SALORT-CAMPANA E., GUYE M., BEUF O., ATTARIAN S., BENDAHAN D. “Combined quantification of fatty infiltration, T1-relaxation times and T2*-relaxation times in normal-appearing skeletal muscle of controls and dystrophic patients.”. Magnetic Resonance Materials in Physics, Biology and Medicine [En ligne]. 2017. Vol. 30, n°4, p. 407-415. Disponible sur : < http://dx.doi.org/10.1007/s10334-017-0616-1 >
    Résumé : ObjectivesTo evaluate the combination of a fat–water separation method with an automated segmentation algorithm to quantify the intermuscular fatty-infiltrated fraction, the relaxation times, and the microscopic fatty infiltration in the normal-appearing muscle.Materials and methodsMR acquisitions were performed at 1.5T in seven patients with facio-scapulo-humeral dystrophy and eight controls. Disease severity was assessed using commonly used scales for the upper and lower limbs. The fat–water separation method provided proton density fat fraction (PDFF) and relaxation times maps (T2* and T1). The segmentation algorithm distinguished adipose tissue and normal-appearing muscle from the T2* map and combined active contours, a clustering analysis, and a morphological closing process to calculate the index of fatty infiltration (IFI) in the muscle compartment defined as the relative amount of pixels with the ratio between the number of pixels within IMAT and the total number of pixels (IMAT + normal appearing muscle).ResultsIn patients, relaxation times were longer and a larger fatty infiltration has been quantified in the normal-appearing muscle. T2* and PDFF distributions were broader. The relaxation times were correlated to the Vignos scale whereas the microscopic fatty infiltration was linked to the Medwin-Gardner-Walton scale. The IFI was linked to a composite clinical severity scale gathering the whole set of scales.ConclusionThe MRI indices quantified within the normal-appearing muscle could be considered as potential biomarkers of dystrophies and quantitatively illustrate tissue alterations such as inflammation and fatty infiltration.
    Mots-clés : crmbm, Magnetic Resonance Imaging, Muscle dystrophies, Segmentation.


  • LUTZ N. W., BERNARD M. “Multiparametric quantification of thermal heterogeneity within aqueous materials by water 1H NMR spectroscopy: Paradigms and algorithms.”. PLOS ONE [En ligne]. 2017. Vol. 12, n°5, p. e0178431. Disponible sur : < http://dx.doi.org/10.1371/journal.pone.0178431 >
    Résumé : Processes involving heat generation and dissipation play an important role in the performance of numerous materials. The behavior of (semi-)aqueous materials such as hydrogels during production and application, but also properties of biological tissue in disease and therapy (e.g., hyperthermia) critically depend on heat regulation. However, currently available thermometry methods do not provide quantitative parameters characterizing the overall temperature distribution within a volume of soft matter. To this end, we present here a new paradigm enabling accurate, contactless quantification of thermal heterogeneity based on the line shape of a water proton nuclear magnetic resonance (1H NMR) spectrum. First, the 1H NMR resonance from water serving as a "temperature probe" is transformed into a temperature curve. Then, the digital points of this temperature profile are used to construct a histogram by way of specifically developed algorithms. We demonstrate that from this histogram, at least eight quantitative parameters describing the underlying statistical temperature distribution can be computed: weighted median, weighted mean, standard deviation, range, mode(s), kurtosis, skewness, and entropy. All mathematical transformations and calculations are performed using specifically programmed EXCEL spreadsheets. Our new paradigm is helpful in detailed investigations of thermal heterogeneity, including dynamic characteristics of heat exchange at sub-second temporal resolution.
    Mots-clés : Algorithms, crmbm, Distribution curves, Entropy, Gels, NMR spectroscopy, Nuclear magnetic resonance, Skewness, Statistical distributions.


  • MAAROUF A., AUDOIN B., PARIOLLAUD F., GHERIB S., RICO A., SOULIER E., CONFORT-GOUNY S., GUYE M., SCHAD L., PELLETIER J., RANJEVA J. - P., ZAARAOUI W. “Increased total sodium concentration in gray matter better explains cognition than atrophy in MS.”. Neurology [En ligne]. 2017. Vol. 88, n°3, p. 289-295. Disponible sur : < http://dx.doi.org/10.1212/WNL.0000000000003511 >
    Résumé : Objective: To investigate whether brain total sodium accumulation assessed by 23Na MRI is associated with cognitive deficit in relapsing-remitting multiple sclerosis (RRMS). Methods: Eighty-nine participants were enrolled in the study (58 patients with RRMS with a disease duration ≤10 years and 31 matched healthy controls). Patients were classified as cognitively impaired if they failed at least 2 tasks on the Brief Repeatable Battery. MRI was performed at 3T using 23Na MRI to obtain total sodium concentration (TSC) in the different brain compartments (lesions, normal-appearing white matter [NAWM], gray matter [GM]) and 1H- magnetization-prepared rapid gradient echo to assess GM atrophy (GM fraction). Results: The mean disease duration was 3.1 years and the median Expanded Disability Status Scale score was 1 (range 0–4.5). Thirty-seven patients were classified as cognitively preserved and 21 as cognitively impaired. TSC was increased in GM and NAWM in cognitively impaired patients compared to cognitively preserved patients and healthy controls. Voxel-wise analysis demonstrated that sodium accumulation was mainly located in the neocortex in cognitively impaired patients. Regression analysis evidenced than the 2 best independent predictors of cognitive impairment were GM TSC and age. Receiver operating characteristic analyses demonstrated that sensitivity and specificity of the GM TSC to classify patients according to their cognitive status were 76% and 71%, respectively. Conclusions: This study provides 2 main findings. (1) In RRMS, total sodium accumulation in the GM is better associated with cognitive impairment than GM atrophy; and (2) total sodium accumulation in patients with cognitive impairment is mainly located in the neocortex.
    Mots-clés : crmbm.

  • MACE P., MILH M., GIRARD N., SIGAUDY S., QUARELLO E. “[How to deal with a fetal head circumference lower than the third percentile?].”. Gynecologie, Obstetrique, Fertilite & Senologie [En ligne]. 2017. Disponible sur : < http://dx.doi.org/10.1016/j.gofs.2017.07.004 > (consulté le no date)
    Résumé : The prenatal finding of a head circumference (HC) below the 3rd percentile (p) remains, in the same way as short femur or increased nuchal translucency with normal karyotype, one the most difficult situations for the praticionner in the setting of prenatal diagnosis. Microcephaly is a gateway to possible cerebral pathologies, but the main objective is to identify serious prenatal situations. A standardized HC measurement, the use of adapted reference tools and charts, longitudinal following of cephalic biometrics in high-risk situations, and systematic central nervous system analysis can increase the diagnostic performance of ultrasound which is often disappointing for microcephaly. The early distinction between associated or isolated microcephaly makes it possible to quickly orient the prenatal management and counseling. Fetal MRI and genetic counseling are fundamental in this context, making it possible to specify at best the etiological diagnosis and to provide assistance to the neuropediatrician in the establishment of an often uncertain prognosis. The recent increase in cases of microcephaly concomitant with the epidemic of the ZIKA virus is an additional argument to improve our practices and the daily apprehension of HC<3rd p.


  • PREVOST V. H., GIRARD O. M., MCHINDA S., VARMA G., ALSOP D. C., DUHAMEL G. “Optimization of inhomogeneous magnetization transfer (ihMT) MRI contrast for preclinical studies using dipolar relaxation time (T1D) filtering.”. NMR in Biomedicine [En ligne]. 2017. Vol. 30, n°6,. Disponible sur : < http://dx.doi.org/10.1002/nbm.3706 >

  • PROIX T., BARTOLOMEI F., GUYE M., JIRSA V. K. “Individual brain structure and modelling predict seizure propagation.”. Brain: A Journal of Neurology [En ligne]. 2017. Vol. 140, n°3, p. 641-654. Disponible sur : < http://dx.doi.org/10.1093/brain/awx004 > (consulté le no date)
    Résumé : See Lytton (doi:10.1093/awx018) for a scientific commentary on this article.Neural network oscillations are a fundamental mechanism for cognition, perception and consciousness. Consequently, perturbations of network activity play an important role in the pathophysiology of brain disorders. When structural information from non-invasive brain imaging is merged with mathematical modelling, then generative brain network models constitute personalized in silico platforms for the exploration of causal mechanisms of brain function and clinical hypothesis testing. We here demonstrate with the example of drug-resistant epilepsy that patient-specific virtual brain models derived from diffusion magnetic resonance imaging have sufficient predictive power to improve diagnosis and surgery outcome. In partial epilepsy, seizures originate in a local network, the so-called epileptogenic zone, before recruiting other close or distant brain regions. We create personalized large-scale brain networks for 15 patients and simulate the individual seizure propagation patterns. Model validation is performed against the presurgical stereotactic electroencephalography data and the standard-of-care clinical evaluation. We demonstrate that the individual brain models account for the patient seizure propagation patterns, explain the variability in postsurgical success, but do not reliably augment with the use of patient-specific connectivity. Our results show that connectome-based brain network models have the capacity to explain changes in the organization of brain activity as observed in some brain disorders, thus opening up avenues towards discovery of novel clinical interventions.
    Mots-clés : brain network models, connectomes, Epilepsy, individualized medicine, seizure propagation.

  • RASOANANDRIANINA H., GRAPPERON A. - M., TASO M., GIRARD O. M., DUHAMEL G., GUYE M., RANJEVA J. - P., ATTARIAN S., VERSCHUEREN A., CALLOT V. “Region-specific impairment of the cervical spinal cord (SC) in amyotrophic lateral sclerosis: A preliminary study using SC templates and quantitative MRI (diffusion tensor imaging/inhomogeneous magnetization transfer).”. NMR in biomedicine [En ligne]. 2017. Disponible sur : < http://dx.doi.org/10.1002/nbm.3801 > (consulté le no date)
    Résumé : In this preliminary study, our objective was to investigate the potential of high-resolution anatomical imaging, diffusion tensor imaging (DTI) and conventional/inhomogeneous magnetization transfer imaging [magnetization transfer (MT)/inhomogeneous magnetization transfer (ihMT)] at 3 T, analyzed with template-extracted regions of interest, to measure the atrophy and structural changes of white (WM) and gray (GM) matter spinal cord (SC) occurring in patients with amyotrophic lateral sclerosis (ALS). Ten patients with ALS and 20 age-matched healthy controls were recruited. SC GM and WM areas were automatically segmented using dedicated templates. Atrophy indices were evaluated from T2 *-weighted images at each vertebral level from cervical C1 to C6. DTI and ihMT metrics were quantified within the corticospinal tract (CST), posterior sensory tract (PST) and anterior GM (aGM) horns at the C2 and C5 levels. Clinical disabilities of patients with ALS were evaluated using the Revised ALS Functional Rating Scale, upper motor neuron (UMN) and Medical Research Council scorings, and correlated with MR metrics. Compared with healthy controls, GM and WM atrophy was observed in patients with ALS, especially at lower cervical levels, where a strong correlation was also observed between GM atrophy and the UMN score (R = -0.75, p = 0.05 at C6). Interestingly, a significant decrease in ihMT ratio was found in all regions of interest (p < 0.0008), fractional anisotropy (FA) and MT ratios decreased significantly in CST, especially at C5 (p < 0.005), and λ// (axial diffusivity) decreased significantly in CST (p = 0.0004) and PST (p = 0.003) at C2. Strong correlations between MRI metrics and clinical scores were also found (0.47 < |R| < 0.87, p < 0.05). Altogether, these preliminary results suggest that high-resolution anatomical imaging and ihMT imaging, in addition to DTI, are valuable for the characterization of SC tissue impairment in ALS. In this study, in addition to an important SC WM demyelination, we also observed, for the first time in ALS, impairments of cervical aGM.
    Mots-clés : ALS, crmbm, diffusion tensor imaging, GM atrophy, inhomogeneous magnetization transfer, motor neuron, spinal cord, spinal cord templates.

  • RIDLEY B., MARCHI A., WIRSICH J., SOULIER E., CONFORT-GOUNY S., SCHAD L., BARTOLOMEI F., RANJEVA J. - P., GUYE M., ZAARAOUI W. “Brain sodium MRI in human epilepsy: Disturbances of ionic homeostasis reflect the organization of pathological regions.”. NeuroImage [En ligne]. 2017. Vol. 157, p. 173-183. Disponible sur : < http://dx.doi.org/10.1016/j.neuroimage.2017.06.011 > (consulté le no date)
    Résumé : In light of technical advancements supporting exploration of MR signals other than (1)H, sodium ((23)Na) has received attention as a marker of ionic homeostasis and cell viability. Here, we evaluate for the first time the possibility that (23)Na-MRI is sensitive to pathological processes occurring in human epilepsy. A normative sample of 27 controls was used to normalize regions of interest (ROIs) from 1424 unique brain locales on quantitative (23)Na-MRI and high-resolution (1)H-MPRAGE images. ROIs were based on intracerebral electrodes in ten patients undergoing epileptic network mapping. The stereo-EEG gold standard was used to define regions as belonging to primarily epileptogenic, secondarily irritative and to non-involved regions. Estimates of total sodium concentration (TSC) on (23)Na-MRI and cerebrospinal fluid (CSF) on (1)H imaging were extracted for each patient ROI, and normalized against the same region in controls. ROIs with disproportionate CSF contributions (ZCSF≥1.96) were excluded. TSC levels were found to be elevated in patients relative to controls except in one patient, who suffered non-convulsive seizures during the scan, in whom we found reduced TSC levels. In the remaining patients, an ANOVA (F1100= 12.37, p<0.0001) revealed a highly significant effect of clinically-defined zones (F1100= 11.13, p<0.0001), with higher normalized TSC in the epileptogenic zone relative to both secondarily irritative (F1100= 11, p=0.0009) and non-involved regions (F1100= 17.8, p<0.0001). We provide the first non-invasive, in vivo evidence of a chronic TSC elevation alongside ZCSF levels within the normative range, associated with the epileptogenic region even during the interictal period in human epilepsy, and the possibility of reduced TSC levels due to seizure. In line with modified homeostatic mechanisms in epilepsy - including altered mechanisms underlying ionic gating, clearance and exchange - we provide the first indication of (23)Na-MRI as an assay of altered sodium concentrations occurring in epilepsy associated with the organization of clinically relevant divisions of pathological cortex.
    Mots-clés : Cortical localisation, crmbm, Epilepsy, Epilepsy surgery, Intracranial EEG, Ionic imaging, Sodium MRI.

  • RIDLEY B., WIRSICH J., BETTUS G., RODIONOV R., MURTA T., CHAUDHARY U., CARMICHAEL D., THORNTON R., VULLIEMOZ S., MCEVOY A., WENDLING F., BARTOLOMEI F., RANJEVA J. - P., LEMIEUX L., GUYE M. “Simultaneous Intracranial EEG-fMRI Shows Inter-Modality Correlation in Time-Resolved Connectivity Within Normal Areas but Not Within Epileptic Regions.”. Brain Topography [En ligne]. 2017. Disponible sur : < http://dx.doi.org/10.1007/s10548-017-0551-5 > (consulté le no date)
    Résumé : For the first time in research in humans, we used simultaneous icEEG-fMRI to examine the link between connectivity in haemodynamic signals during the resting-state (rs) and connectivity derived from electrophysiological activity in terms of the inter-modal connectivity correlation (IMCC). We quantified IMCC in nine patients with drug-resistant epilepsy (i) within brain networks in 'healthy' non-involved cortical zones (NIZ) and (ii) within brain networks involved in generating seizures and interictal spikes (IZ1) or solely spikes (IZ2). Functional connectivity (h (2) ) estimates for 10 min of resting-state data were obtained between each pair of electrodes within each clinical zone for both icEEG and fMRI. A sliding window approach allowed us to quantify the variability over time of h (2) (vh (2)) as an indicator of connectivity dynamics. We observe significant positive IMCC for h (2) and vh (2), for multiple bands in the NIZ only, with the strongest effect in the lower icEEG frequencies. Similarly, intra-modal h (2) and vh (2) were found to be differently modified as a function of different epileptic processes: compared to NIZ, [Formula: see text] was higher in IZ1, but lower in IZ2, while [Formula: see text] showed the inverse pattern. This corroborates previous observations of inter-modal connectivity discrepancies in pathological cortices, while providing the first direct invasive and simultaneous comparison in humans. We also studied time-resolved FC variability multimodally for the first time, finding that IZ1 shows both elevated internal [Formula: see text] and less rich dynamical variability, suggesting that its chronic role in epileptogenesis may be linked to greater homogeneity in self-sustaining pathological oscillatory states.
    Mots-clés : connectivity, crmbm, Dynamic connectivity, Focal epilepsy, Multimodal imaging, Resting-state.

  • ROUX V., SALAUN E., TRIBOUILLOY C., HUBERT S., BOHBOT Y., CASALTA J. - P., BARRAL P. - A., RUSINARU D., GOURIET F., LAVOUTE C., HAENTJENS J., DI BISCEGLI M., DEHAENE A., RENARD S., CASALTA A. - C., PRADIER J., AVIERINOS J. - F., RIBERI A., LAMBERT M., COLLART F., JACQUIER A., THUNY F., CAMOIN-JAU L., LEPIDI H., RAOULT D., HABIB G. “Coronary events complicating infective endocarditis.”. Heart (British Cardiac Society) [En ligne]. 2017. Disponible sur : < http://dx.doi.org/10.1136/heartjnl-2017-311624 > (consulté le no date)
    Résumé : OBJECTIVE: Acute coronary syndromes (ACS) are a rare complication of infective endocarditis (IE). Only case reports and small studies have been published to date. We report the largest series of ACS in IE. The aim of our study was to describe the incidence and mechanisms of ACS associated with IE, to assess their prognostic impact and to describe their management. METHODS: In a bicentre prospective observational cohort study, all patients with a definite diagnosis of IE were prospectively included. The incidence, mechanism and prognosis of patients with ACS were studied. RESULTS: Among 1210 consecutive patients with definite IE, 26 patients (2.2%) developed an ACS. Twenty-three patients (88%) had a coronary embolism. Two patients had coronary compression by an abscess or a pseudoaneurysm and one patient had an obstruction of his bioprosthesis and left coronary ostium by a large vegetation. Nineteen (73%) patients with ACS developed heart failure and this complication was 2.5 times more frequent than in patients without ACS (p<0.0001). In the ACS population, mortality rate was twice than the population without ACS. CONCLUSIONS: ACS is a rare complication of IE but is associated with an increased risk of heart failure and high mortality rate.
    Mots-clés : acute coronary syndromes, endocarditis.


  • SCHWESER F., ROBINSON S. D., DE ROCHEFORT L., LI W., BREDIES K. “An illustrated comparison of processing methods for phase MRI and QSM: removal of background field contributions from sources outside the region of interest.”. NMR in Biomedicine [En ligne]. 2017. Vol. 30, n°4,. Disponible sur : < http://dx.doi.org/10.1002/nbm.3604 >
    Mots-clés : background field removal, phase imaging, phase processing, QSM, review, susceptibility mapping.

  • WEGRZYK J., RANJEVA J. - P., FOURÉ A., KAVOUNOUDIAS A., VILMEN C., MATTEI J. - P., GUYE M., MAFFIULETTI N. A., PLACE N., BENDAHAN D., GONDIN J. “Specific brain activation patterns associated with two neuromuscular electrical stimulation protocols.”. Scientific Reports [En ligne]. 2017. Vol. 7, n°1, p. 2742. Disponible sur : < http://dx.doi.org/10.1038/s41598-017-03188-9 > (consulté le no date)
    Résumé : The influence of neuromuscular electrical stimulation (NMES) parameters on brain activation has been scarcely investigated. We aimed at comparing two frequently used NMES protocols - designed to vary in the extent of sensory input. Whole-brain functional magnetic resonance imaging was performed in sixteen healthy subjects during wide-pulse high-frequency (WPHF, 100 Hz-1 ms) and conventional (CONV, 25 Hz-0.05 ms) NMES applied over the triceps surae. Each protocol included 20 isometric contractions performed at 10% of maximal force. Voluntary plantar flexions (VOL) were performed as control trial. Mean force was not different among the three protocols, however, total current charge was higher for WPHF than for CONV. All protocols elicited significant activations of the sensorimotor network, cerebellum and thalamus. WPHF resulted in lower deactivation in the secondary somatosensory cortex and precuneus. Bilateral thalami and caudate nuclei were hyperactivated for CONV. The modulation of the NMES parameters resulted in differently activated/deactivated regions related to total current charge of the stimulation but not to mean force. By targeting different cerebral brain regions, the two NMES protocols might allow for individually-designed rehabilitation training in patients who can no longer execute voluntary movements.
    Mots-clés : crmbm.

  • WIRSICH J., RIDLEY B., BESSON P., JIRSA V., BÉNAR C., RANJEVA J. - P., GUYE M. “Complementary contributions of concurrent EEG and fMRI connectivity for predicting structural connectivity.”. NeuroImage [En ligne]. 2017. Disponible sur : < http://dx.doi.org/10.1016/j.neuroimage.2017.08.055 > (consulté le no date)
    Résumé : While averaged dynamics of brain function are known to estimate the underlying structure, the exact relationship between large-scale function and structure remains an unsolved issue in network neuroscience. These complex functional dynamics, measured by EEG and fMRI, are thought to arise from a shared underlying structural architecture, which can be measured by diffusion MRI (dMRI). While simulation and data transformation (e.g. graph theory measures) have been proposed to refine the understanding of the underlying function-structure relationship, the potential complementary and/or independent contribution of EEG and fMRI to this relationship is still poorly understood. As such, we explored this relationship by analyzing the function-structure correlation in fourteen healthy subjects with simultaneous resting-state EEG-fMRI and dMRI acquisitions. We show that the combination of EEG and fMRI connectivity better explains dMRI connectivity and that this represents a genuine model improvement over fMRI-only models for both group-averaged connectivity matrices and at the individual level. Furthermore, this model improves the prediction within each resting-state network. The best model fit to underlying structure is mediated by fMRI and EEG-δ connectivity in combination with Euclidean distance and interhemispheric connectivity with more local contributions of EEG-γ at the scale of resting state networks. This highlights that the factors mediating the relationship between functional and structural metrics of connectivity are context and scale dependent, influenced by topological, geometric and architectural features. It also suggests that fMRI studies employing simultaneous EEG measures may characterize additional and essential parts of the underlying neuronal activity of the resting-state, which might be of special interest for both clinical studies and the investigation of resting-state dynamics.
    Mots-clés : Brain connectivity, Connectome, crmbm, Multimodal, Network theory.

  • ZHOU Z., HAN F., RAPACCHI S., NGUYEN K. - L., BRUNENGRABER D. Z., KIM G. - H. J., FINN J. P., HU P. “Accelerated ferumoxytol-enhanced 4D multiphase, steady-state imaging with contrast enhancement (MUSIC) cardiovascular MRI: validation in pediatric congenital heart disease.”. NMR in biomedicine [En ligne]. 2017. Vol. 30, n°1,. Disponible sur : < http://dx.doi.org/10.1002/nbm.3663 > (consulté le no date)
    Résumé : The purpose of this work was to validate a parallel imaging (PI) and compressed sensing (CS) combined reconstruction method for a recently proposed 4D non-breath-held, multiphase, steady-state imaging technique (MUSIC) cardiovascular MRI in a cohort of pediatric congenital heart disease patients. We implemented a graphics processing unit accelerated CS-PI combined reconstruction method and applied it in 13 pediatric patients who underwent cardiovascular MRI after ferumoxytol administration. Conventional breath-held contrast-enhanced magnetic resonance angiography (CE-MRA) was first performed during the first pass of ferumoxytol injection, followed by the original MUSIC and the proposed CS-PI MUSIC during the steady-state distribution phase of ferumoxytol. Qualities of acquired images were then evaluated using a four-point scale. Left ventricular volumes and ejection fractions calculated from the original MUSIC and the CS-PI MUSIC were also compared with conventional multi-slice 2D cardiac cine MRI. The proposed CS-PI MUSIC reduced the imaging time of the MUSIC acquisition to 4.6 ± 0.4 min from 8.9 ± 1.2 min. Computationally intensive image reconstruction was completed within 5 min without interruption of sequential clinical scans. The proposed method (mean 3.3-4.0) provided image quality comparable to that of the original MUSIC (3.2-4.0) (all P ≥ 0.42), and better than conventional breath-held first-pass CE-MRA (1.1-3.3) for 13 anatomical structures (all P ≤ 0.0014) with good inter-observer agreement (κ > 0.46). The calculated ventricular volumes and ejection fractions from both original MUSIC (r > 0.90) and CS-PI MUSIC (r > 0.85) correlated well with 2D cine imaging. In conclusion, PI and CS were successfully incorporated into the 4D MUSIC acquisition to further reduce scan time by approximately 50% while maintaining highly comparable image quality in a clinically practical reconstruction time.
    Mots-clés : cardiac cine, compressed sensing, Ferumoxytol, Magnetic Resonance Angiography, Parallel imaging, pediatric MRI.

  • ZHOU Z., HAN F., YU S., YU D., RAPACCHI S., SONG H. K., WANG D. J. J., HU P., YAN L. “Accelerated noncontrast-enhanced 4-dimensional intracranial MR angiography using golden-angle stack-of-stars trajectory and compressed sensing with magnitude subtraction.”. Magnetic Resonance in Medicine [En ligne]. 2017. Disponible sur : < http://dx.doi.org/10.1002/mrm.26747 > (consulté le no date)
    Résumé : PURPOSE: To evaluate the feasibility and performance of compressed sensing (CS) with magnitude subtraction regularization in accelerating non-contrast-enhanced dynamic intracranial MR angiography (NCE-dMRA). METHODS: A CS algorithm was introduced in NCE-dMRA by exploiting the sparsity of the magnitude difference of the control and label images. The NCE-dMRA data were acquired using golden-angle stack-of-stars trajectory on six healthy volunteers and one patient with arteriovenous fistula. Images were reconstructed using (i) the proposed magnitude-subtraction CS (MS-CS); (ii) complex-subtraction CS; (iii) independent CS; and (iv) view-sharing with k-space weighted image contrast (KWIC). The dMRA image quality was compared across the four reconstruction strategies. The proposed MS-CS method was further compared with KWIC for temporal fidelity of depicting dynamic flow. RESULTS: The proposed MS-CS method was able to reconstruct NCE-dMRA images with detailed vascular structures and clean background. It provided better subjective image quality than the other two CS strategies (P < 0.05). Compared with KWIC, MS-CS showed similar image quality, but reduced temporal blurring in delineating the fine distal arteries. CONCLUSIONS: The MS-CS method is a promising CS technique for accelerating NCE-dMRA acquisition without compromising image quality and temporal fidelity. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
    Mots-clés : arterial spin labeling, compressed sensing, KWIC, magnitude subtraction, noncontrast MR angiography, view sharing.

2016

Journal Article

  • ABDESSELAM I., DUTOUR A., KOBER F., ANCEL P., BEGE T., DARMON P., LESAVRE N., BERNARD M., GABORIT B. “Time Course of Change in Ectopic Fat Stores After Bariatric Surgery.”. Journal of the American College of Cardiology [En ligne]. 2016. Vol. 67, n°1, p. 117-119. Disponible sur : < http://dx.doi.org/10.1016/j.jacc.2015.10.052 > (consulté le no date)

  • BAL-THEOLEYRE L., LALANDE A., KOBER F., GIORGI R., COLLART F., PIQUET P., HABIB G., AVIERINOS J. - F., BERNARD M., GUYE M., JACQUIER A. “Aortic Function's Adaptation in Response to Exercise-Induced Stress Assessing by 1.5T MRI: A Pilot Study in Healthy Volunteers.”. PloS One [En ligne]. 2016. Vol. 11, n°6, p. e0157704. Disponible sur : < http://dx.doi.org/10.1371/journal.pone.0157704 > (consulté le no date)
    Résumé : AIM: Evaluation of the aortic "elastic reserve" might be a relevant marker to assess the risk of aortic event. Our aim was to compare regional aortic elasticity at rest and during supine bicycle exercise at 1.5 T MRI in healthy individuals. METHODS: Fifteen volunteers (8 men), with a mean age of 29 (23-41) years, completed the entire protocol. Images were acquired immediately following maximal exercise. Retrospective cine sequences were acquired to assess compliance, distensibility, maximum rates of systolic distension and diastolic recoil at four different locations: ascending aorta, proximal descending aorta, distal descending aorta and aorta above the coeliac trunk level. Segmental aortic pulse wave velocity (PWV) was assessed by through plane velocity-encoded MRI. RESULTS: Exercise induced a significant decrease of aortic compliance and distensibility, and a significant increase of the absolute values of maximum rates of systolic distension and diastolic recoil at all sites (p<10-3). At rest and during stress, ascending aortic compliance was statistically higher compared to the whole descending aorta (p≤0.0007). We found a strong correlation between the rate pressure product and aortic distensibility at all sites (r = - 0.6 to -0.75 according to the site, p<10-4). PWV measured at the proximal and distal descending aorta increased significantly during stress (p = 0.02 and p = 0.008, respectively). CONCLUSION: Assessment of regional aortic function during exercise is feasible using MRI. During stress, aortic elasticity decreases significantly in correlation with an increase of the PWV. Further studies are required to create thresholds for ascending aorta dysfunction among patients with aneurysms, and to monitor the impact of medication on aortic remodeling.
    Mots-clés : Adaptation, Physiological, Adult, Aorta, Aorta, Thoracic, crmbm, Diastole, Elasticity, Exercise, Female, Healthy Volunteers, Humans, Magnetic Resonance Imaging, Male, Pilot Projects, Pulse Wave Analysis, Stress, Physiological, Supine Position, Systole, Vascular Stiffness.

  • BÉCHIR N., PECCHI E., VILMEN C., LE FUR Y., AMTHOR H., BERNARD M., BENDAHAN D., GIANNESINI B. “ActRIIB blockade increases force-generating capacity and preserves energy supply in exercising mdx mouse muscle in vivo.”. FASEB journal: official publication of the Federation of American Societies for Experimental Biology [En ligne]. 2016. Vol. 30, n°10, p. 3551-3562. Disponible sur : < http://dx.doi.org/10.1096/fj.201600271RR > (consulté le no date)
    Résumé : Postnatal blockade of the activin type IIB receptor (ActRIIB) represents a promising therapeutic strategy for counteracting dystrophic muscle wasting. However, its impact on muscle function and bioenergetics remains poorly documented in physiologic conditions. We have investigated totally noninvasively the effect of 8-wk administration of either soluble ActRIIB signaling inhibitor (sActRIIB-Fc) or vehicle PBS (control) on gastrocnemius muscle force-generating capacity, energy metabolism, and anatomy in dystrophic mdx mice using magnetic resonance (MR) imaging and dynamic [(31)P]-MR spectroscopy ([(31)P]-MRS) in vivo ActRIIB inhibition increased muscle volume (+33%) without changing fiber-type distribution, and increased basal animal oxygen consumption (+22%) and energy expenditure (+23%). During an in vivo standardized fatiguing exercise, maximum and total absolute contractile forces were larger (+40 and 24%, respectively) in sActRIIB-Fc treated animals, whereas specific force-generating capacity and fatigue resistance remained unaffected. Furthermore, sActRIIB-Fc administration did not alter metabolic fluxes, ATP homeostasis, or contractile efficiency during the fatiguing bout of exercise, although it dramatically reduced the intrinsic mitochondrial capacity for producing ATP. Overall, sActRIIB-Fc treatment increased muscle mass and strength without altering the fundamental weakness characteristic of dystrophic mdx muscle. These data support the clinical interest of ActRIIB blockade for reversing dystrophic muscle wasting.-Béchir, N., Pecchi, E., Vilmen, C., Le Fur, Y., Amthor, H., Bernard, M., Bendahan, D., Giannesini, B. ActRIIB blockade increases force-generating capacity and preserves energy supply in exercising mdx mouse muscle in vivo.
    Mots-clés : crmbm, Duchenne muscular dystrophy, Muscle Fatigue, myostatin inhibition, skeletal muscle hypertrophy.

  • BERNARD J. Y., ARMAND M., FORHAN A., DE AGOSTINI M., CHARLES M. - A., HEUDE B. “Early life exposure to polyunsaturated fatty acids and psychomotor development in children from the EDEN mother-child cohort.”. Ocl-Oilseeds and Fats Crops and Lipids [En ligne]. 2016. Vol. 23, n°1, p. D106. Disponible sur : < http://dx.doi.org/10.1051/ocl/2015060 > (consulté le no date)
    Résumé : Epidemiological studies have reported that breastfed children have improved psychomotor development compared to never breastfed children. Human studies suggest that polyunsaturated fatty acids (PUFA), especially long chain PUFA (LC-PUFA) which are highly contained in breast milk, could explain this link, since they are needed for pre-and postnatal brain development. Our aim was to study the relationships between several measures of pre-and postnatal exposures to PUFA and child's psychomotor development at 2 and 3 years in the EDEN cohort. We evaluated breastfeeding duration, colostrum PUFA levels and maternal dietary PUFA intake during pregnancy, that we related with three scores of psychomotor development, after taking into account potential confounders. Breastfeeding duration was positively associated with psychomotor development. No relationship was found with both pre-and postnatal exposure to LC-PUFA. However, the maternal dietary omega-6/omega-3 ratio was negatively associated with psychomotor development, mainly driven by intake in linoleic acid (LA). Among breastfed children, linoleic acid levels were negatively associated with psychomotor development. Furthermore, children exposed to the highest colostrum LA levels tended to score closer to never breastfed children than to children exposed to the lowest colostrums LA levels. Taken together, these results do not provide evidence in favour of a positive role of pre-and postnatal exposure to LC-PUFA on later psychomotor development, but highlight a potential negative role of being exposed in early life to high LA levels. From a public health perspective, this work reiterates the need to promote breastfeeding duration, and to monitor the balance of PUFA intake during pregnancy and lactation periods.
    Mots-clés : age, Brain, breast milk, breast-feeding duration, cognitive-development, Cohort Studies, docosahexaenoic acid, fish intake, iq, maternal nutrition, Milk, polyunsaturated fatty acids, Pregnancy, psychomotor development, requirements.

  • BERNARD M., MAIXENT J. - M., GERBI A., LAN C., COZZONE P. J., PIERONI G., ARMAND M., COSTE T. C. “Dietary docosahexaenoic acid-enriched glycerophospholipids exert cardioprotective effects in ouabain-treated rats via physiological and metabolic changes.”. Food & Function [En ligne]. 2016. Vol. 7, n°2, p. 798-804. Disponible sur : < http://dx.doi.org/10.1039/c5fo01300c > (consulté le no date)
    Résumé : Docosahexaenoic acid (DHA) might prevent heart failure or optimise drug treatments by improving cardiac contraction. We investigated whether DHA-enriched avian glycerophospholipids (GPL-DHA) exert cardioprotection in ouabain-treated rats after 4 weeks of dietary supplementation with 10, 35 or 60 mg DHA per kg body weight versus none (DHA10, DHA35, DHA60 and control groups, respectively). The contractile responsiveness to different doses of ouabain (10(-7) to 10(-4) M), ouabain intoxication (at 3 × 10(-4) M), and relative variations in cardiac energy metabolism were determined using (31)P NMR in isolated perfused rat hearts. The fatty acid composition of cardiac membranes was analysed by gas chromatography. DHA accretion in the heart was dose-dependent (+8%, +30% and +45% for DHA10, DHA35 and DHA60, respectively). The cardiac phosphocreatine content significantly increased at the baseline in DHA35 (+45%) and DHA60 groups (+85%), and at the different doses of ouabain in the DHA60 group (+73% to 98%). The maximum positive inotropy achieved at 10(-4) M ouabain was significantly increased in all DHA groups versus control (+150%, +122.5% and +135% for DHA10, DHA35 and DHA60, respectively), and ouabain intoxication was delayed. The increase in myocardial phosphocreatine content and the improved efficacy of ouabain on myocardial contraction without toxicity suggest the potential of GPL-DHA as a dietary supplement or ingredient for functional food, and possibly as a co-treatment with digitalis drugs in humans.
    Mots-clés : crmbm.

  • BOUTIèRE C., REY C., ZAARAOUI W., LE TROTER A., RICO A., CRESPY L., ACHARD S., REUTER F., PARIOLLAUD F., WIRSICH J., ASQUINAZI P., CONFORT-GOUNY S., SOULIER E., GUYE M., PELLETIER J., RANJEVA J. - P., AUDOIN B. “Improvement of spasticity following intermittent theta burst stimulation in multiple sclerosis is associated with modulation of resting-state functional connectivity of the primary motor cortices.”. Multiple Sclerosis (Houndmills, Basingstoke, England) [En ligne]. 2016. Disponible sur : < http://dx.doi.org/10.1177/1352458516661640 > (consulté le no date)
    Résumé : BACKGROUND: Intermittent theta burst stimulation (iTBS) of the primary motor cortex improves transiently lower limbs spasticity in multiple sclerosis (MS). However, the cerebral mechanisms underlying this effect have never been investigated. OBJECTIVE: To assess whether modulation of spasticity induced by iTBS is underlined by functional reorganization of the primary motor cortices. METHODS: A total of 17 patients with MS suffering from lower limbs spasticity were randomized to receive real iTBS or sham iTBS during the first half of a 5-week indoor rehabilitation programme. Spasticity was assessed using the Modified Ashworth Scale and the Visual Analogue Scale at baseline, after the stimulation session and at the end of the rehabilitation programme. Resting-state functional magnetic resonance imaging (fMRI) was performed at the three time points, and brain functional networks topology was analysed using graph-theoretical approach. RESULTS: At the end of stimulation, improvement of spasticity was greater in real iTBS group than in sham iTBS group (p = 0.026). iTBS had a significant effect on the balance of the connectivity degree between the stimulated and the homologous primary motor cortex (p = 0.005). Changes in inter-hemispheric balance were correlated with improvement of spasticity (rho = 0.56, p = 0.015). CONCLUSION: This longitudinal resting-state fMRI study evidences that functional reorganization of the primary motor cortices may underlie the effect of iTBS on spasticity in MS.
    Mots-clés : connectivity, crmbm, intermittent theta burst stimulation, Multiple Sclerosis, primary motor cortex, resting state fMRI, spasticity.

  • BRAUD L., BATTAULT S., MEYER G., NASCIMENTO A., GAILLARD S., DE SOUSA G., RAHMANI R., RIVA C., ARMAND M., MAIXENT J. - M., REBOUL C. “Antioxidant properties of tea blunt ROS-dependent lipogenesis: beneficial effect on hepatic steatosis in a high fat-high sucrose diet NAFLD obese rat model.”. The Journal of Nutritional Biochemistry [En ligne]. 2016. Vol. 40, p. 95-104. Disponible sur : < http://dx.doi.org/10.1016/j.jnutbio.2016.10.012 > (consulté le no date)
    Résumé : Oxidative stress could trigger lipid accumulation in liver and thus hepatic steatosis. Tea is able to prevent liver disorders, but a direct link between antioxidant capacities and prevention of steatosis has not been reported yet. We aimed to investigate such relationship in a rat model of high fat-high sucrose diet (HFS)-induced obesity and to explore more deeply the mechanisms in isolated hepatocytes. Wistar rats were divided into a control group (standard diet), an HFS group (high fat-sucrose diet) and an HFS+tea group (HFS diet with ad-libitum access to tea drink). Body weight, fat mass, glycemic parameters in blood, lipid and oxidative stress parameters in blood and liver were measured in each group after 14 weeks. Isolated hepatocytes were treated with the reactive oxygen species (ROS) inducer t-BHP in the presence or not of antioxidants (tempol or tea), and superoxide anion production and lipid accumulation were measured using specific fluorescent probes. We reported that the HFS diet highly increased hepatic lipids content, while tea consumption attenuated steatosis and improved the oxidative status (decrease in hepatic oxidative stress, increase in plasma total antioxidant capacity). The role of antioxidant properties of tea in such phenomenon was confirmed in primary cultured rat hepatocytes. Indeed, the increase of mitochondrial ROS production with t-BHP resulted in lipid accumulation in hepatocytes (positive linear regression), and antioxidants (tempol or tea) normalized both. We reported that the antioxidant properties of tea protect rats from an obesogenic HFS diet-induced hepatic steatosis by counteracting the ROS-dependent lipogenesis.
    Mots-clés : Antilipogenesis, Antioxidant, Camellia sinensis, Mitochondrial ROS, NAFLD, Obesogenic diet.

  • BRICQ S., FRANDON J., BERNARD M., GUYE M., FINAS M., MARCADET L., MIQUEROL L., KOBER F., HABIB G., FAGRET D., JACQUIER A., LALANDE A. “Semiautomatic detection of myocardial contours in order to investigate normal values of the left ventricular trabeculated mass using MRI.”. Journal of magnetic resonance imaging: JMRI [En ligne]. 2016. Vol. 43, n°6, p. 1398-1406. Disponible sur : < http://dx.doi.org/10.1002/jmri.25113 > (consulté le no date)
    Résumé : PURPOSE: To propose, assess, and validate a semiautomatic method allowing rapid and reproducible measurement of trabeculated and compacted left ventricular (LV) masses from cardiac magnetic resonance imaging (MRI). MATERIALS AND METHODS: We developed a method to automatically detect noncompacted, endocardial, and epicardial contours. Papillary muscles were segmented using semiautomatic thresholding and were included in the compacted mass. Blood was removed from trabeculae using the same threshold tool. Trabeculated, compacted masses and ratio of noncompacted to compacted (NC:C) masses were computed. Preclinical validation was performed on four transgenic mice with hypertrabeculation of the LV (high-resolution cine imaging, 11.75T). Then analysis was performed on normal cine-MRI examinations (steady-state free precession [SSFP] sequences, 1.5T or 3T) obtained from 60 healthy participants (mean age 49 ± 16 years) with 10 men and 10 women for each of the following age groups: [20,39], [40,59], and [60,79]. Interobserver and interexamination segmentation reproducibility was assessed by using Bland-Altman analysis and by computing the correlation coefficient. RESULTS: In normal participants, noncompacted and compacted masses were 6.29 ± 2.03 g/m(2) and 62.17 ± 11.32 g/m(2) , respectively. The NC:C mass ratio was 10.26 ± 3.27%. Correlation between the two observers was from 0.85 for NC:C ratio to 0.99 for end-diastolic volume (P < 10(-5) ). The bias between the two observers was -1.06 ± 1.02 g/m(2) for trabeculated mass, -1.41 ± 2.78 g/m(2) for compacted mass, and -1.51 ± 1.77% for NC:C ratio. CONCLUSION: We propose a semiautomatic method based on region growing, active contours, and thresholding to calculate the NC:C mass ratio. This method is highly reproducible and might help in the diagnosis of LV noncompaction cardiomyopathy. J. Magn. Reson. Imaging 2016;43:1398-1406.
    Mots-clés : cardiovascular magnetic resonance imaging, crmbm, left ventricle, noncompaction, papillary muscles, trabeculae.

  • CHEN Z., ZHANG X., YUAN C., ZHAO X., VAN OSCH M. J. P. “Measuring the labeling efficiency of pseudocontinuous arterial spin labeling.”. Magnetic Resonance in Medicine [En ligne]. 2016. Disponible sur : < http://dx.doi.org/10.1002/mrm.26266 > (consulté le no date)
    Résumé : PURPOSE: Optimization and validation of a sequence for measuring the labeling efficiency of pseudocontinuous arterial spin labeling (pCASL) perfusion MRI. METHODS: The proposed sequence consists of a labeling module and a single slice Look-Locker echo planar imaging readout. A model-based algorithm was used to calculate labeling efficiency from the signal acquired from the main brain-feeding arteries. Stability of the labeling efficiency measurement was evaluated with regard to the use of cardiac triggering, flow compensation and vein signal suppression. Accuracy of the measurement was assessed by comparing the measured labeling efficiency to mean brain pCASL signal intensity over a wide range of flip angles as applied in the pCASL labeling. RESULTS: Simulations show that the proposed algorithm can effectively calculate labeling efficiency when correcting for T1 relaxation of the blood spins. Use of cardiac triggering and vein signal suppression improved stability of the labeling efficiency measurement, while flow compensation resulted in little improvement. The measured labeling efficiency was found to be linearly (R = 0.973; P < 0.001) related to brain pCASL signal intensity over a wide range of pCASL flip angles. CONCLUSION: The optimized labeling efficiency sequence provides robust artery-specific labeling efficiency measurement within a short acquisition time (∼30 s), thereby enabling improved accuracy of pCASL CBF quantification. Magn Reson Med, 2016. © 2016 Wiley Periodicals, Inc.
    Mots-clés : Arterial spin labeling (ASL), labeling efficiency, MRI, perfusion imaging, pseudocontinuous.

  • COHEN J. A., KHATRI B., BARKHOF F., COMI G., HARTUNG H. - P., MONTALBAN X., PELLETIER J., STITES T., RITTER S., VON ROSENSTIEL P., TOMIC D., KAPPOS L., TRANSFORMS (TRIAL ASSESSING INJECTABLE INTERFERON VS. FTY720 ORAL IN RRMS) STUDY GROUP. “Long-term (up to 4.5 years) treatment with fingolimod in multiple sclerosis: results from the extension of the randomised TRANSFORMS study.”. Journal of Neurology, Neurosurgery, and Psychiatry [En ligne]. 2016. Vol. 87, n°5, p. 468-475. Disponible sur : < http://dx.doi.org/10.1136/jnnp-2015-310597 > (consulté le no date)
    Résumé : OBJECTIVE: The 12-month (M), phase 3, double-blind, randomised TRANSFORMS study demonstrated significant benefits of fingolimod 0.5 or 1.25 mg over interferon β-1a (IFNβ-1a) in patients with relapsing-remitting multiple sclerosis. We report the results of long-term (up to 4.5 years) extension of TRANSFORMS. METHODS: Patients randomised to fingolimod (0.5/1.25 mg) in the core phase continued the same dose (continuous-fingolimod) in the extension, whereas those on IFNβ-1a were re-randomised (1:1) to fingolimod (IFN-switch; IFN: 0.5/1.25 mg). Outcomes included annualised relapse rate (ARR), confirmed disability progression and MRI measures. Results are presented here for the continuous-fingolimod 0.5 mg and pooled IFN-switch groups. RESULTS: Of the 1027 patients who entered the extension, 772 (75.2%) completed the study. From baseline to the end of the study (EOS), ARR in patients on continuous-fingolimod 0.5 mg was significantly lower than in the IFN-switch group (M0-EOS: 0.17 vs 0.27). After switching to fingolimod (M0-12 vs M13-EOS), patients initially treated with IFN had a 50% reduction in ARR (0.40 vs 0.20), reduced MRI activity and a lower rate of brain volume loss. In a post hoc analysis, the proportion of IFN-switch patients with no evidence of disease activity increased by approximately 50% in the first year after switching to fingolimod treatment (44.3% to 66.0%). The safety profile was consistent with that observed in the core phase. CONCLUSIONS: These results support a continued effect of long-term fingolimod therapy in maintaining a low rate of disease activity and sustained improved efficacy after switching from IFNβ-1a to fingolimod. CLINICAL TRIAL REGISTRATION NO: NCT00340834.

  • DE LEENER B., TASO M., COHEN-ADAD J., CALLOT V. “Segmentation of the human spinal cord.”. Magma (New York, N.Y.) [En ligne]. 2016. Vol. 29, n°2, p. 125-153. Disponible sur : < http://dx.doi.org/10.1007/s10334-015-0507-2 > (consulté le no date)
    Résumé : Segmenting the spinal cord contour is a necessary step for quantifying spinal cord atrophy in various diseases. Delineating gray matter (GM) and white matter (WM) is also useful for quantifying GM atrophy or for extracting multiparametric MRI metrics into specific WM tracts. Spinal cord segmentation in clinical research is not as developed as brain segmentation, however with the substantial improvement of MR sequences adapted to spinal cord MR investigations, the field of spinal cord MR segmentation has advanced greatly within the last decade. Segmentation techniques with variable accuracy and degree of complexity have been developed and reported in the literature. In this paper, we review some of the existing methods for cord and WM/GM segmentation, including intensity-based, surface-based, and image-based methods. We also provide recommendations for validating spinal cord segmentation techniques, as it is important to understand the intrinsic characteristics of the methods and to evaluate their performance and limitations. Lastly, we illustrate some applications in the healthy and pathological spinal cord. One conclusion of this review is that robust and automatic segmentation is clinically relevant, as it would allow for longitudinal and group studies free from user bias as well as reproducible multicentric studies in large populations, thereby helping to further our understanding of the spinal cord pathophysiology and to develop new criteria for early detection of subclinical evolution for prognosis prediction and for patient management. Another conclusion is that at the present time, no single method adequately segments the cord and its substructure in all the cases encountered (abnormal intensities, loss of contrast, deformation of the cord, etc.). A combination of different approaches is thus advised for future developments, along with the introduction of probabilistic shape models. Maturation of standardized frameworks, multiplatform availability, inclusion in large suite and data sharing would also ultimately benefit to the community.
    Mots-clés : crmbm, Gray matter, MRI, Segmentation, spinal cord, white matter.

  • DOCHE E., LECOCQ A., MAAROUF A., DUHAMEL G., SOULIER E., CONFORT-GOUNY S., RICO A., GUYE M., AUDOIN B., PELLETIER J., RANJEVA J. - P., ZAARAOUI W. “Hypoperfusion of the thalamus is associated with disability in relapsing remitting multiple sclerosis.”. Journal of Neuroradiology. Journal De Neuroradiologie [En ligne]. 2016. Disponible sur : < http://dx.doi.org/10.1016/j.neurad.2016.10.001 > (consulté le no date)
    Résumé : BACKGROUND: While gray matter (GM) perfusion abnormalities have been evidenced in multiple sclerosis (MS) patients, the relationships with disability still remain unclear. Considering that atrophy is known to impact on perfusion, we aimed to assess perfusion abnormalities in GM of MS patients, outside atrophic regions and investigate relationships with disability. METHODS: Brain perfusion of 23 relapsing remitting MS patients and 16 matched healthy subjects were assessed at 3T using the pseudo-continuous arterial spin labeling magnetic resonance imaging technique. In order to locate potential GM perfusion abnormalities in regions spared by atrophy, we combined voxelwise comparisons of GM cerebral blood flow (CBF) maps (cortex and deep GM) (P<0.005, FWE-corrected) and voxel-based-morphometry analysis (P<0.005, FDR-corrected) to exclude atrophic regions. Disability was assessed using the Expanded Disability Status Scale (EDSS) and the Multiple Sclerosis Functional Composite score (MSFC). RESULTS: In patients, significant GM hypoperfusion outside atrophic regions was depicted only in bilateral thalami. No other cluster was found to be hypoperfused compared to controls. Perfusion of thalami was correlated to MSFC (P=0.011, rho=0.523). A trend of correlation was found between perfusion of thalami and EDSS (P=0.061, rho=-0.396). CONCLUSION: In relapsing remitting MS, perfusion abnormalities in thalamic regions contribute to disability. These findings suggest that functional impairments of thalami, representing a major brain hub, may disturb various cerebral functions even before structural damage.
    Mots-clés : Atrophy, crmbm, Disability, Multiple Sclerosis, perfusion, Pseudo-continuous arterial spin labeling, Thalamus.

  • DONADIEU M., LE FUR Y., CONFORT-GOUNY S., LE TROTER A., GUYE M., RANJEVA J. - P. “Evidencing different neurochemical profiles between thalamic nuclei using high resolution 2D-PRESS semi-LASER (1)H-MRSI at 7 T.”. Magma (New York, N.Y.) [En ligne]. 2016. Disponible sur : < http://dx.doi.org/10.1007/s10334-016-0556-1 > (consulté le no date)
    Résumé : OBJECTIVE: 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 <0.3 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 < 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 < 0.0001), with significant effect of nucleus type (p < 0.0001) and hemisphere (p < 0.0001). Post hoc analyses showed differences in neurochemical profiles between the left and the right hemisphere (p < 0.05), and differences in neurochemical profiles between nuclei within each hemisphere (p < 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.
    Mots-clés : 1H-MRSI, Connectivity atlas, crmbm, Neurochemical profiles, Thalamic nuclei, Ultra high field.

  • DONADIEU M., LE FUR Y., LECOCQ A., MAUDSLEY A. A., GHERIB S., SOULIER E., CONFORT-GOUNY S., PARIOLLAUD F., RANJEVA M. - P., PELLETIER J., GUYE M., ZAARAOUI W., AUDOIN B., RANJEVA J. - P. “Metabolic voxel-based analysis of the complete human brain using fast 3D-MRSI: Proof of concept in multiple sclerosis.”. Journal of magnetic resonance imaging: JMRI [En ligne]. 2016. Vol. 44, n°2, p. 411-419. Disponible sur : < http://dx.doi.org/10.1002/jmri.25139 > (consulté le no date)
    Résumé : PURPOSE: To detect local metabolic abnormalities over the complete human brain in multiple sclerosis (MS) patients, we used optimized fast volumic echo planar spectroscopic imaging (3D-EPSI). MATERIALS AND METHODS: Weighted mean combination of two 3D-EPSI covering the whole brain acquired at 3T in AC-PC and AC-PC+15° axial planes was performed to obtain high-quality metabolite maps for five metabolites: N-acetyl aspartate (NAA), glutamate+glutamine (Glx), choline (Cho), myo-inositol (m-Ins), and creatine+phosphocreatine (tCr). After spatial normalization, maps from 19 patients suffering from relapsing-remitting MS were compared to 19 matched controls using statistical mapping analyses to determine the topography of metabolic abnormalities. Probabilistic white matter (WM) T2 lesion maps and gray matter (GM) atrophy maps were also generated. RESULTS: Two-group analysis of variance (ANOVA) (SPM8, P < 0.005, false discovery rate [FDR]-corrected P < 0.05 at the cluster level with age and sex as confounding covariates) comparing patients and controls matched for age and sex showed clusters of abnormal metabolite levels with 1) decreased NAA (around -15%) and Glx (around 20%) predominantly in GM within prefrontal cortices, motor cortices, bilateral thalami, and mesial temporal cortices in line with neuronal/neuro-astrocytic dysfunction; 2) increased m-Ins (around + 20%) inside WM T2 lesions and in the normal-appearing WM of temporal-occipital lobes, suggesting glial activation. CONCLUSION: We demonstrate the ability to noninvasively map over the complete brain-from vertex to cerebellum-with a validated sequence, the metabolic abnormalities associated with MS, for characterizing the topography of pathological processes affecting widespread areas of WM and GM and its functional impact. J. Magn. Reson. Imaging 2016;44:411-419.
    Mots-clés : crmbm, Inflammation, Multiple Sclerosis, neurodegeneration, proton magnetic resonance spectroscopic imaging, statistical mapping analysis, whole brain.

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