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Des cils battent dans le cerveau à un tempo finement régulé

Grégory Conductier, Angèle Viola, Arnaud le Troter, Jean-Louis Nahon, Alice Guyon
2013 M S.Médecine Sciences  
Grâce à des études récentes, les mécanismes contrôlant la mise en place Des cils battent dans le cerveau à un tempo finement régulé Grégory Conductier 1 , Angèle Viola 2 , Arnaud le Troter 2 , Jean-Louis  ...  De façon spectaculaire, seules les cellules ciliées en contact avec les fibres à MCH expriment le MCHR1 dans le 3 e ventricule.  ... 
doi:10.1051/medsci/20132911004 pmid:24280491 fatcat:d5naxqivnbg5tgnsbzx34yt6mq

Model-Driven Harmonic Parameterization of the Cortical Surface [chapter]

Guillaume Auzias, Julien Lefèvre, Arnaud Le Troter, Clara Fischer, Matthieu Perrot, Jean Régis, Olivier Coulon
2011 Lecture Notes in Computer Science  
In the context of inter-subject brain surface matching, we present a parameterization of the cortical surface constrained by a model of cortical organization. The parameterization is defined via an harmonic mapping of each hemisphere surface to a rectangular planar domain that integrates a representation of the model. As opposed to previous conformal mapping methods we do not match folds between individuals but instead optimize the fit between cortical sulci and specific iso-coordinate axis in
more » ... he model. Experiments on both hemispheres of 34 subjects are presented and results are very promising.
doi:10.1007/978-3-642-23629-7_38 fatcat:rjvbikspkbfnpmqyvpu7dsnkli

2D Multi-Class Model for Gray and White Matter Segmentation of the Cervical Spinal Cord at 7T [article]

Nilser J. Laines Medina, Charley Gros, Julien Cohen-Adad, Virginie Callot, Arnaud Le Troter
2021 arXiv   pre-print
The spinal cord (SC), which conveys information between the brain and the peripheral nervous system, plays a key role in various neurological disorders such as multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS), in which both gray matter (GM) and white matter (WM) may be impaired. While automated methods for WM/GM segmentation are now largely available, these techniques, developed for conventional systems (3T or lower) do not necessarily perform well on 7T MRI data, which feature
more » ... ner details, contrasts, but also different artifacts or signal dropout. The primary goal of this study is thus to propose a new deep learning model that allows robust SC/GM multi-class segmentation based on ultra-high resolution 7T T2*-w MR images. The second objective is to highlight the relevance of implementing a specific data augmentation (DA) strategy, in particular to generate a generic model that could be used for multi-center studies at 7T.
arXiv:2110.06516v1 fatcat:jvnil2gqkjdrffasdx6xr4bf7m

Localization and quantification of intramuscular damage using statistical parametric mapping and skeletal muscle parcellation

Alexandre Fouré, Arnaud Le Troter, Maxime Guye, Jean-Pierre Mattei, David Bendahan, Julien Gondin
2015 Scientific Reports  
In the present study, we proposed an original and robust methodology which combines the spatial normalization of skeletal muscle images, the statistical parametric mapping (SPM) analysis and the use of a specific parcellation in order to accurately localize and quantify the extent of skeletal muscle damage within the four heads of the quadriceps femoris. T 2 maps of thigh muscles were characterized before, two (D2) and four (D4) days after 40 maximal isometric electrically-evoked contractions
more » ... 25 healthy young males. On the basis of SPM analysis of coregistrated T 2 maps, the alterations were similarly detected at D2 and D4 in the superficial and distal regions of the vastus medialis (VM) whereas the proportion of altered muscle was higher in deep muscle regions of the vastus lateralis at D4 (deep: 35 ± 25%, superficial: 23 ± 15%) as compared to D2 (deep: 18 ± 13%, superficial: 17 ± 13%). The present methodology used for the first time on skeletal muscle would be of utmost interest to detect subtle intramuscular alterations not only for the diagnosis of muscular diseases but also for assessing the efficacy of potential therapeutic interventions and clinical treatment strategies. Unaccustomed exercises and neuromuscular diseases can lead to the occurrence of skeletal muscle damage 1-7 . These alterations are associated with several physiological events leading to inflammatory processes within muscle 1,6,8-11 . Magnetic resonance imaging (MRI) appears as a method of choice to investigate in vivo the extent of muscle damage in healthy subjects 12-16 or in patients with neuromuscular diseases 4,7,17,18 . MRI is a powerful non-invasive tool allowing for a spatially-resolved analysis of muscle tissue 4, 15, 19 . The increase in muscle proton transverse relaxation time (T 2 ) has been identified as a relevant biomarker of muscle damage 15,19-22 illustrating an inflammatory/edematous process 6,13,23-28 . Different T 2 changes among muscles have been already reported after exercise-induced muscle damage 15,21,22 and in dystrophic boys 4 . In most of these studies, the averaged T 2 value was calculated in regions of interest within a given muscle thereby ignoring any spatial information. Although local T 2 changes were assessed along muscles 19, 22 , no study provided information on the accurate localization and extent of intramuscular damage into the three dimensions (3D) of a skeletal muscle. Yet, accurate localization and quantification of muscle damage should provide more robust indices in diagnosis and longitudinal follow-ups of diseases or injuries. So far, only one study has reported information related to the distribution of intramuscular damage in dystrophic boys 7 . However, the analysis was only performed on a limited muscle volume (i.e., three MRI slices) and no information was provided on the localization of the most damaged areas within the muscle 7 . Moreover, we recently showed that neuromuscular electrostimulation (NMES) induced spatially heterogeneous T 2 changes in quadriceps femoris (QF) muscle group 22 with higher alterations in superficial muscles located beneath the stimulation electrodes (i.e., vastus lateralis [VL] and vastus medialis [VM]). On the sole basis of visual inspection of T 2 maps, we consistently observed that altered muscle areas were heterogeneously distributed within the damaged muscle. Due to large inter-individual morphologic differences (e.g., muscle/tendon length, muscle volume), the 3D coregistration of MR images appears essential to accurately
doi:10.1038/srep18580 pmid:26689827 pmcid:PMC4686971 fatcat:bqdu7sfgyzg4lmhhx4lsxzglyy

Muscle Quantitative MR Imaging and Clustering Analysis in Patients with Facioscapulohumeral Muscular Dystrophy Type 1

Emilie Lareau-Trudel, Arnaud Le Troter, Badih Ghattas, Jean Pouget, Shahram Attarian, David Bendahan, Emmanuelle Salort-Campana, Yong Fan
2015 PLoS ONE  
Facioscapulohumeral muscular dystrophy type 1 (FSHD1) is the third most common inherited muscular dystrophy. Considering the highly variable clinical expression and the slow disease progression, sensitive outcome measures would be of interest. The qMRI provides a sensitive measurement of fat fraction which should also be of high interest to assess disease progression and any therapeutic strategy in FSHD1 patients. Quantitative MRI in FSHD1 Patients PLOS ONE | Fig 6. Correlation of intramuscular
more » ... fat fraction with mean visual score of muscular fatty infiltration. A: Correlation between the mean visual score of the thighs and the intramuscular fat fraction. B: Correlation between the mean visual score of the thighs and the Log of the intramuscular fat fraction.
doi:10.1371/journal.pone.0132717 pmid:26181385 pmcid:PMC4504465 fatcat:tmplwvzqo5g2pok365mjn3gcaa

Localization And Quantification Of Intramuscular Damage Using Statistical Parametric Mapping And Skeletal Muscle Parcellation

Alexandre Fouré, Arnaud Le Troter, Maxime Guye, Jean-Pierre Mattei, David Bendahan, Julien Gondin
2016 Medicine & Science in Sports & Exercise  
doi:10.1249/01.mss.0000487849.11202.da fatcat:q4ufrgf3yba5zjpwt4p3zcd53i

Structural Connectivity Alterations in Amyotrophic Lateral Sclerosis: A Graph Theory Based Imaging Study

Etienne Fortanier, Aude-Marie Grapperon, Arnaud Le Troter, Annie Verschueren, Ben Ridley, Maxime Guye, Shahram Attarian, Jean-Philippe Ranjeva, Wafaa Zaaraoui
2019 Frontiers in Neuroscience  
Copyright © 2019 Fortanier, Grapperon, Le Troter, Verschueren, Ridley, Guye, Attarian, Ranjeva and Zaaraoui.  ... 
doi:10.3389/fnins.2019.01044 pmid:31632235 pmcid:PMC6783612 fatcat:t5darpemkjhhpptewx4aoh4mue

Whole-brain quantitative mapping of metabolites using short echo three-dimensional proton MRSI

Angèle Lecocq, Yann Le Fur, Andrew A. Maudsley, Arnaud Le Troter, Sulaiman Sheriff, Mohamad Sabati, Maxime Donnadieu, Sylviane Confort-Gouny, Patrick J. Cozzone, Maxime Guye, Jean-Philippe Ranjeva
2014 Journal of Magnetic Resonance Imaging  
Purpose-To improve the extent over which whole brain quantitative 3D-MRSI maps can be obtained and be used to explore brain metabolism in a population of healthy volunteers. Materials and Methods-Two short TE (20 ms) acquisitions of 3D Echo Planar Spectroscopic Imaging at two orientations, one in the anterior commissure -posterior commissure (AC-PC) plane and the second tilted in the AC-PC +15° plane were obtained at 3T in a group of ten healthy volunteers. B 1 + , B 1 − , and B 0 correction
more » ... cedures and normalization of metabolite signals with quantitative water proton density measurements were performed. A combination of the two spatially normalized 3D-MRSI, using a weighted mean based on the pixel wise standard deviation metabolic maps of each orientation obtained from the whole group, provided metabolite maps for each subject allowing regional metabolic profiles of all parcels of the automated anatomical labeling (AAL) atlas to be obtained. Results- The combined metabolite maps derived from the two acquisitions reduced the regional inter-subject variance. The numbers of AAL regions showing NAA SD/Mean ratios lower than 30% increased from 17 in the AC-PC orientation and 41 in the AC-PC+15° orientation, to a value of 76 regions out of 116 for the combined NAA maps. Quantitatively, regional differences in absolute metabolite concentrations (mM) over the whole brain were depicted such as in the GM of frontal lobes ( c NAA =10.03+1.71, c Cho =1.78±0.55, c Cr =7.29±1.69; c mIns =5.30±2.67) and in cerebellum (c NAA =5.28±1.77, c Cho =1.60±0.41, c Cr =6.95±2.15; c mIns =3.60±0.74). Conclusion-A double-angulation acquisition enables improved metabolic characterization over a wide volume of the brain. Fast proton magnetic resonance spectroscopic imaging (MRSI) enables mapping of magnetic resonance (MR)-observable metabolites within the brain in a time compatible with clinical exams (1-4). The feasibility of whole-brain 3D-MRSI has been demonstrated (5,6) and reproducibility evaluated (7,8) , indicating the value of this technique for studies of physiology (9) or for clinical applications, such as studies of Parkinson's disease (10) , traumatic brain injury (11) or epilepsy (12) . The requirement to obtain information over a wide region of the brain places increased demands on the quality of B 0 shimming and RF pulse profiles. First, susceptibility variations cause local B 0 distortions that cannot be corrected for using the commonly available shim terms, resulting in both local (intra-voxel) inhomogeneities, which degrade the MRS signal quality, as well as regions with incomplete water suppression as a result of more global and slowly-varying inhomogeneities. The magnitude and distribution of the residual field inhomogeneity is influenced by the B 0 shimming capabilities, the region over which shimming is performed, and the shape of structures within the head relative to the B 0 field (13). The effect of the local inhomogeneity can be partially reduced by using spatial oversampling methods to obtain smaller nominal voxel volumes, although at the expense of some loss in the signal-to-noise ratio and increase in the spatial sampling requirements. Several orientations of the imaging volume relative to the brain have been used, with alignment in the anterior commissure -posterior commissure (AC-PC) plane (11, 14) , in the AC-PC +10° plane (5,15) or in the AC-PC+15° plane (11) to minimize B 0 inhomogeneity; however, an analysis of the relative performance of these differences has not been presented. An additional factor that affects spectral quality is non-ideal RF pulse profiles and inhomogeneities, particularly at higher field strengths, combined with the effect of chemicalshift differences, which lead to variable signal intensity and loss of signal in distal parts of the excited region. Large brain coverage therefore requires correction for inhomogeneities of the transmit (B 1 +) and receive (B 1 −) radiofrequency fields (16-18). A second limitation to the wider use of volumetric MRSI is the influence of strong signals from subcutaneous lipids that can contaminate voxels within the brain, which can occur even with the implementation of lipid suppression methods. To lessen the impact of these lipid signals, most previous clinical applications (6, 11, 14) have used medium to long TEs (≥70ms), which limits the observed metabolites to N-Acetyl Aspartate (NAA), total Creatine (Cr) and total choline (Cho) levels and incurs some T2 signal loss. Finally, for comparative measurements of single metabolites the normalization procedures remain an important consideration. Accurate quantification methods are time consuming and complex, and therefore several semi-quantitative methods have been proposed (19-22) of which the most time efficient and robust uses normalization of spectroscopic data with tissue water density derived from a MRI measurement (19, 20, 23, 24) . Lecocq et al.
doi:10.1002/jmri.24809 pmid:25431032 pmcid:PMC4447620 fatcat:vmqwe2wx3jf45o2qcha3tlc6tq

Time Course of Central and Peripheral Alterations after Isometric Neuromuscular Electrical Stimulation-Induced Muscle Damage

Alexandre Fouré, Kazunori Nosaka, Jennifer Wegrzyk, Guillaume Duhamel, Arnaud Le Troter, Hélène Boudinet, Jean-Pierre Mattei, Christophe Vilmen, Marc Jubeau, David Bendahan, Julien Gondin, Kelvin E. Jones
2014 PLoS ONE  
Isometric contractions induced by neuromuscular electrostimulation (NMES) have been shown to result in a prolonged force decrease but the time course of the potential central and peripheral factors have never been investigated. This study examined the specific time course of central and peripheral factors after isometric NMES-induced muscle damage. Twentyfive young healthy men were subjected to an NMES exercise consisting of 40 contractions for both legs. Changes in maximal voluntary
more » ... force of the knee extensors (MVC), peak evoked force during double stimulations at 10 Hz (Db 10 ) and 100 Hz (Db 100 ), its ratio (10:100), voluntary activation, muscle soreness and plasma creatine kinase activity were assessed before, immediately after and throughout four days after NMES session. Changes in knee extensors volume and T 2 relaxation time were also assessed at two (D2) and four (D4) days post-exercise. MVC decreased by 29% immediately after NMES session and was still 19% lower than the baseline value at D4. The decrease in Db 10 was higher than in Db 100 immediately and one day post-exercise resulting in a decrease (212%) in the 10:100 ratio. On the contrary, voluntary activation significantly decreased at D2 (25%) and was still depressed at D4 (25%). Muscle soreness and plasma creatine kinase activity increased after NMES and peaked at D2 and D4, respectively. T 2 was also increased at D2 (6%) and D4 (9%). Additionally, changes in MVC and peripheral factors (e.g., Db 100 ) were correlated on the full recovery period, while a significant correlation was found between changes in MVC and VA only from D2 to D4. The decrease in MVC recorded immediately after the NMES session was mainly due to peripheral changes while both central and peripheral contributions were involved in the prolonged force reduction. Interestingly, the chronological events differ from what has been reported so far for voluntary exercise-induced muscle damage.
doi:10.1371/journal.pone.0107298 pmid:25215511 pmcid:PMC4162582 fatcat:gwek7xzccvcr5gxd2xdrocaqze

A Motion Correction Strategy for Multi-Contrast based 3D parametric imaging: Application to Inhomogeneous Magnetization Transfer (ihMT) [article]

Lucas Soustelle, Julien Lamy, Arnaud Le Troter, Andreea Hertanu, Maxime Guye, Jean-Philippe Ranjeva, Gopal Varma, David C. Alsop, Jean Pelletier, Olivier Girard, Guillaume Duhamel
2020 bioRxiv   pre-print
Purpose To propose an efficient retrospective image-based method for motion correction of multi-contrast acquisitions with a low number of available images (MC-MoCo) and evaluate its use in 3D inhomogeneous Magnetization Transfer (ihMT) experiments in the human brain. Methods A framework for motion correction, including image pre-processing enhancement and rigid registration to an iteratively improved target image, was developed. The proposed method was compared to Motion Correction with
more » ... Linear Image Registration Tool (MCFLIRT) function in FSL over 13 subjects. Native (pre-correction) and residual (post-correction) motions were evaluated by means of markers positioned at well-defined anatomical regions over each image. Results Both motion correction strategies significantly reduced inter-image misalignment, and the MC-MoCo method yielded significantly better results than MCFLIRT. Conclusion MC-MoCo is a high-performance method for motion correction of multi-contrast volumes as in 3D ihMT imaging.
doi:10.1101/2020.09.11.292649 fatcat:shooargvv5acfiuqn3csa4nhby

Alien Hand, Restless Brain: Salience Network and Interhemispheric Connectivity Disruption Parallel Emergence and Extinction of Diagonistic Dyspraxia

Ben Ridley, Marion Beltramone, Jonathan Wirsich, Arnaud Le Troter, Eve Tramoni, Sandrine Aubert, Sophie Achard, Jean-Philippe Ranjeva, Maxime Guye, Olivier Felician
2016 Frontiers in Human Neuroscience  
Ridley et al. Longitudinal Changes in Alien Hand Connectomics This also raises the possibility that changes to large-scale functional architecture revealed by resting-state functional magnetic resonance imaging (fMRI) (rs-fMRI) may provide relevant information on the evolution of behavioral syndromes in addition to that provided by structural and task-based functional imaging.
doi:10.3389/fnhum.2016.00307 pmid:27378896 pmcid:PMC4913492 fatcat:kxnnuxeswjg77b6a5hn55s3nj4

Combined MRI and 31P-MRS Investigations of the ACTA1(H40Y) Mouse Model of Nemaline Myopathy Show Impaired Muscle Function and Altered Energy Metabolism

Charlotte Gineste, Yann Le Fur, Christophe Vilmen, Arnaud Le Troter, Emilie Pecchi, Patrick J. Cozzone, Edna C. Hardeman, David Bendahan, Julien Gondin, Ralf Krahe
2013 PLoS ONE  
Citation: Gineste C, Le Fur Y, Vilmen C, Le Troter A, Pecchi E, et al. (2013) Combined MRI and 31 P-MRS Investigations of the ACTA1(H40Y) Mouse Model of Nemaline Myopathy Show Impaired Muscle Function  ... 
doi:10.1371/journal.pone.0061517 pmid:23613869 pmcid:PMC3629063 fatcat:qh37mpqbu5d6fet4a3gsuzrkhe

Are We Heading to the Future of Musculoskeletal Tumor Imaging with Ultra-High Field 7T MRI?

Jean-Camille MATTEI, Alexandre Foure, Alexandre Rochwerger, Arnaud Le Troter, Arthur Varoquaux, Christophe Chagnaud, Corinne Bouvier, David Bendahan, Jean-Camille MATTEI, Maxime Guye, Sandrine Guis, Sébastien Salas
2020 Clinical Oncology and Research  
and objectives: Sarcoma preoperative planning critically depends on MRI, sometimes uninformative when compartments barriers or critical structures are involved. objective: to prospectively assess the feasibility and the potential of 7T MRI in sarcoma. Methods: Two patients with femoral chondrosarcoma were CT and MRI (1.5 and 7T) scanned with T1W, T2W, GRE and DTI sequences. Image quality and characteristics of the tumors were compared between these modalities. Results: In-plane resolution was
more » ... gher at 7T as compared to 1.5T MRI, tumor delineation was more reliable and soft tissue involvement was clearer. DT imaging and corresponding ADC mapping allowed a clear distinction between edema and tumor and identified tumor involvement of collateral ligament allowing healthy structures sparing with histopathology confirmation. 7T MRI was also able to define cortical reaction as precisely as CT imaging. Conclusion: Musculoskeletal tumours UHF-MRI is promising. Higher resolution and enhanced signal to noise ratio improved tumoral assessment, infiltration and cortex changes. One could expect this nonradiating technique to replace CT investigation for bone tumours assessment and open new perspectives in the fields of vascular or nerve salvage and response to chemo/radiotherapy. Healthy tissue sparing might be facilitated with impacts on function, complication or reconstruction type.
doi:10.31487/j.cor.2019.6.02 fatcat:l6fpqoracjccxnqflz6itcv4ei

Knee psoriatic enthesitis assessed using positron emission tomography (PET) – FNa merged to ultrahigh field magnetic resonance imaging (UHF-MRI)

Serge Cammilleri, Sophie Gabriel, Arnaud Le Troter, Christophe Chagnaud, Jean Pierre Mattei, David Bendahan, Sandrine Guis
2019 Joint Bone Spine  
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
doi:10.1016/j.jbspin.2019.01.002 pmid:30660806 fatcat:yow3qkr6yvcwjb6obxwd3nelji

Long-term follow-up of MRI changes in thigh muscles of patients with Facioscapulohumeral dystrophy: A quantitative study

Farzad Fatehi, Emmanuelle Salort-Campana, Arnaud Le Troter, Emilie Lareau-Trudel, Mark Bydder, Alexandre Fouré, Maxime Guye, David Bendahan, Shahram Attarian, Michael Kyba
2017 PLoS ONE  
doi:10.1371/journal.pone.0183825 pmid:28841698 pmcid:PMC5571945 fatcat:fv7w237r7fa2hof37r6amp24mq
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