Thèses sur le sujet « Spectroscopie RMN in vivo »
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Blondet, Pascal. « Spectroscopie RMN localisée haute résolution du proton "in vivo" ». Grenoble 1, 1988. http://www.theses.fr/1988GRE10002.
Texte intégralBlondet, Pascal. « Spectroscopie RMN localisée haute résolution du proton "in vivo" ». Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37612005s.
Texte intégralDesal, Hubert-Armand. « Développements méthodologiques en spectroscopie RMN in vivo pour l'étude des tumeurs cérébrales ». Nantes, 2008. https://archive.bu.univ-nantes.fr/pollux/show/show?id=5ae4877d-3eb7-4e08-8246-57b355a34c3d.
Texte intégralThe first step of our work was the evaluation of the reproducibility and the reliability of different methodological development of localized spectroscopy sequences (PRESS & STEAM) and parameters (TE &TR) on normal volunteers. We have proposed a “home-made” post-processing protocol, which is easily and directly available on the MRI unit. The second step was the application of this protocol to patients with glial brain tumors. We were now able to assess the better methodology using Principal Components Analysis (PCA). PCA has showed to be simple and efficient to visually determine the aggressiveness of the tumor in a graph. Two further preliminary studies were conducted, one evaluating a new strategy to determine the best echo time based on simulated intensity and PCA, the second considering a new and original method (ERETIC) for absolute quantification on a commercial MR unit
Malaquin, Sophie. « Spectroscopie RMN in vivo pondérée en diffusion pour l'étude de la compartimentation du lactate cérébral ». Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPAST196.
Texte intégralIn the gray matter of the brain, lactate is a metabolite known for its role in brain function and metabolism. The main proposed mechanism, the astrocyte-to-neuron shuttle, plays a crucial role in brain metabolism, and disruptions are likely involved in Alzheimer's disease. In the absence of non-invasive tools for measuring lactate compartmentalization, this mechanism remains a subject of controversy. The idea behind this thesis is that diffusion-weighted NMR spectroscopy could enable the non-invasive measurement of lactate compartmentalization: it is possible to obtain information about diffusion properties induced by different cellular microstructures, and since lactate is present in astrocytes, neurons, and the extracellular space, it would suffice to measure its diffusion properties and compare them to the specific signatures of intraneuronal, intra-astrocytic, and extracellular diffusions to obtain information about its compartmentalization. These measurements were conducted in murine models where a change in compartmentalization was suspected, specifically an astrocytic reactivity model with hypertrophied astrocytes and a pathological model of Alzheimer's disease. These results were compared to reference optical and electrochemical measurements that allow for the 'direct' measurement of lactate in different compartments
Izquierdo, Marguerite. « Caractérisation spectrale en spectroscopie RMN in vivo : contribution au développement de méthodes physiques d'investigation ». Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10153.
Texte intégralLigneul, Clémence. « Développements méthodologiques en spectroscopie RMN in vivo pondérée en diffusion pour l'exploration du milieu intracellulaire dans le cerveau de rongeur ». Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS244/document.
Texte intégralIn vivo diffusion-weighted NMR spectroscopy is sensitive to the motion of cerebral metabolites (glutamate, creatine, choline, NAA, myo-inositol, taurine…), allowing the measurement of their apparent diffusion coefficient (ADC). Since these metabolites are purely intracellular, their ADC only depends on the intracellular medium, in particular cytosol viscosity, density of intracellular structures, and the shape and size of cells. In general, metabolite ADC is measured for a single diffusion time Td, equal to a few dozens milliseconds, leaving them time to explore a few micrometers and to interact repeatedly with intracellular structures. Their ADC then potentially depends on all intracellular parameters mentioned above, in a poorly defined way. This thesis presents new spectroscopy methods in the rodent brain to measure ADC over an unprecedented range of Td, from approximately 0.2 milliseconds up to 2 seconds. A first set of measurements has been modeled to extract key morphological brain cell parameters. The sensitivity of these methods to morphological changes in brain cell morphology has first been studied on mice injected with CNTF (ciliary neurotrophic factor), that causes a strong hypertrophy of a specific cell type, astrocytes. Diffusion properties of some metabolites are indeed sensitive to this massive cell morphological change. The last part presents the application to a transgenic mouse model of Huntington’s disease
Baxan, Nicoleta. « Mise en oeuvre de microantennes RMN en perspective d'étude in vivo de métabolites par spectroscopie ». Lyon 1, 2008. http://www.theses.fr/2008LYO10001.
Texte intégralConsidering the need to explore by MR spectroscopy small quantities of tissue, it is possible to create probes with a working volume compatible with such limitations. This work is centred on the research of efficient solutions to create implantable microsensors by microelectronic techniques especially for in vivo application in preclinical purposes. The first chapter of the theses is an overview on the MR microcoil utilisation on the international context. In the second chapter we describe the microcoil development, its spatial sensitivity estimated by simulation and further correlated by MRI enabling us to estimate the active volume close to 2 μl when the microcoil is used as receiver only. The third chapter is dedicated to the evaluation of microcoil performances in tremes of limit of detection. The presented results made possible to validate the use of microcoils associated with MR spectroscopy sequences based on monovoxel techniques and to measure the sensivity of the technique. The last chapter describes a possible pathway to the microcoil implantation on living tissues and also identifying the difficulties of this approach. The example presented here covers the rat brain explorarion. This study presents the concept and the performances of a new generation of microcoils making possible to validate their performances in MR spectroscopy and largely opening innovative possibilities of highly spatial resolved explorations
Tiret, Brice. « Développements méthodologiques en RMN des noyaux X pour l’étude in vivo du métabolisme cérébral pendant la neurodégénérescence ». Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS221.
Texte intégralThe aim of this thesis was to develop at MIRCen new capabilities to observe two key aspects of energy metabolism in rodent brains using X nuclei NMR spectroscopy: glucose consumption with 13C spectroscopy and adenosine triphosphate (ATP) synthesis with 31P measurements. These developments will be used to both expand general understanding of brain metabolism in healthy subjects but also provide technical tools to search for biomarkers in translational projects of drug development applied to neurodegenerative diseases. This work was done at very high field (11.7T) where signal to noise could be maximized. In the first part, we present the optimization of saturation transfer sequence to measure ATP synthesis rate as well as phosphocreatine (PCr) synthesis rate. With ISIS module, the signal was localized to a voxel containing only the brain, eliminating outside source of signal. With the higher spectral resolution offered by high fields, a second, extracellular pool of Pi was characterized which could prevent possible biases in flux quantification of ATP synthesis. This sequence was also applied to measure metabolic adaptation of BACHD rat models (models of Huntington’s disease, HD) where it was found that the 10% increase in PCr concentration could palliate the ATP synthase activity that is halved in this model. In the second part, we present how deeper analysis of 13C data using automatic differential equation writing script was used to better understand the bicompartmental model of glucose degradation to glutamate and glutamine, which accounts for TCA cycle in neurons and astrocytes. Two major corrections were made to the traditional model, to fit mid- and long-term unexplained dynamics. Looking at glutamate and glutamine isotopomer labeling dynamics, the necessity of adding a vesicular glutamate temporal buffer was made evident. The distinction between astrocytic and neuronal pyruvate dilution also showed that astrocytes use up to 6 times more pyruvate than neurons showing intricate metabolic coupling between the two cell types. These results have then been tested in vivo after optimization of the ISIS-DEPT sequence to observe 13C labeling in the rat brain. Finally, experiments combining 31P and 13C spectroscopy were performed on rats chronically intoxicated with 3-NP, a toxin inhibiting TCA cycle which is used as a model of HD
Kienlin, Markus von. « Instrumentation et méthodologie en spectroscopie RMN in vivo suppression de l'eau, édition de spectre et localisation spatiale / ». Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37619193v.
Texte intégralHERIGAULT, GWENAEL. « Spectroscopie rmn du proton in vivo a 1 ou 2 dimensions frequentielles. Application au cerveau de rat tumoral ». Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10157.
Texte intégralKienlin, Markus von. « Instrumentation et méthodologie en spectroscopie RMN du proton in vivo : suppression de l'eau, édition de spectre, localisation spatiale ». Grenoble INPG, 1988. http://www.theses.fr/1988INPG0071.
Texte intégralMarchadour, Charlotte. « Spectroscopie RMN cérébrale pour l’étude du milieu intracellulaire in vivo : développements méthodologiques pour la diffusion à courtes échelles de temps et pour la mesure du pH en détection 31P ». Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112111/document.
Texte intégralNMR spectroscopy is a unique modality to evaluate intracellular environment in vivo. Indeed observed molecules are specifically intracellular and generally have a biochemistry role and a specific cellular compartmentation. That could be a useful tool to understand cell functioning in their environment. My thesis work consisted in development of new sequence in both diffusion and phosphorus NMR spectroscopy.My first study was to develop a diffusion-weighted spectroscopy at ultra-short diffusion time to look at the anomalous diffusion in the rat brain. ADC evolution as a function of time shows that brain metabolites motion is mainly due to random diffusion and that active transport (if exist) are negligible. Data modeling evidences that diffusion at short diffusion time is sensitive to cytoplasm viscosity and short scale crowding. In collaboration with the pharmaceutical company, this technique was chosen to follow up transgenic mice (rTg4510), model of tau pathology. Preliminary results show significant differences of ADC at an early stage of neurodegenerescence (3 and 6 months).Phosphorus spectroscopy allows observation of metabolites directly implicated in energetic processes. During this thesis, localization sequences were developed to measure intracellular pH in the primate striatum. These sequences are supposed to be used to evaluate the potential of pH as a biomarker of neurodegenerescence in a phenotypic model of the Huntington disease in the non-human primate
Zucchi, Maria do Rosário. « Implementação da técnica de espectroscopia in vivo por RMN e sua aplicação na fisiologia do exercício ». Universidade de São Paulo, 1997. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-29012010-154314/.
Texte intégralThe Nuclear Magnetic Resonance (NMR) spectroscopy has been offering many possibilities of research in the areas of Biology and Medicine. One of the most important applications is the 31P in vivo Spectroscopy to study the skeletal muscle physiology. Using this methodology, it is possible to quantify different phosphorus metabolite concentrations that take part of the muscle energetic metabolism, as their variations as a function of muscle contraction. To accomplish the objective of developing the in vivo spectroscopy technique in the NMR laboratory of the IFSC/USP, many modifications to our Solid High Resolution Spectrometer were introduced and probes were constructed. Following these changes, we studied phosphorus compounds metabolic changes in the skeletal muscle and the intracellular pH of rats and mice as a function of electric stimulation and intensive running exercise.
Pineda, Alonso Nashiely Sofia. « Détermination des concentrations des métabolites dans les tumeurs cérébrales par spectroscopie RMN in vivo avec correction des effets de relaxation ». Nantes, 2006. http://www.theses.fr/2006NANT2A07.
Texte intégralN order to optimize the analysis of in vivo 1H-NMR spectra, a post-processing was developed based on the MRI scanner software. The quantification is obtained by the adjustment of a linear combination of simulated massifs (considering the effects of j-modulation and second order) to the experimental spectrum. The concentrations obtained by this method, for the most concentrated metabolites in the brain, are included in the range of the literature values. A statistical principal components analysis (PCA) was carried out on the spectra of patients affected by glioma. Based on the results of PCA, we suggest an optimal protocol of acquisition for the diagnosis and the classification of these tumors. Thanks to the made up database, it is possible to integrate new patients into the PCA and to make a diagnosis based on the zone where they will be positioned. Methodological developments aiming to reduce the measurement time and to increase the precision were also evaluated
Kadjo, Aziz. « Micro-capteurs implantables : étude des critères de performance en vue de l'optimisation des acquisitions par spectroscopie RMN in vivo ». Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10179.
Texte intégralThe objective of this thesis is to evaluate the micro-coil performance, in spectroscopy in vivo and provide any improvements, while respecting the constraints in terms of obstruction and biocompatibility imposed by applications on brain of animal models. Therefore, this work had also to assess the sensitivity understanding of these particular micro-sensors, a notion that has not yet been explored. This document is organized into five chapters: the first one is an "overview" of state of art techniques and a reminder of the work already done in terms of production and in relation to different metabolite "targets". Chapter II presents the instrumental developments undertaken to improve the detection: optimization of adaptation in power and noise matching at the spectrometer input, were also taken into account. The difficulty of maintaining the animal model in a reduced space is solved by providing different configurations of remote settings. The introduction of a low-noise preamplifier is also studied and implemented. The important question of the limit of detection is approached from a theoretical point of view in Chapter III. The interest of this analysis is to assess the performance of micro-coil, we will point out that this new concept enables to describe a spectroscopy facility (sensor associated with a spectrometer for a given experiment). A study of enhancement of the limit of detection by the apodization technique will be addressed and validated on spectroscopy acquisitions. Chapter IV is an implementation in the first part, through modelling, to discuss changes in the limit of detection for some structural changes (size and positioning of the micro-coil). In the second part, an implementation of the limit of detection through spectroscopic experiments will be presented in order to compare the performance of existing coils: a commercial coil and a micro-coil. The biocompatibility of implantable micro-coil treated in Chapter V. The completion of this study was carried out upstream of the theoretical and instrumental aspects in chapter III and IV and that helped their development with a more pragmatic approach
Martel, Dimitri. « Spectroscopie 2D de corrélation quantitative : Méthode de quantification, études expérimentales et applications in vivo ». Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0004/document.
Texte intégralIn in vivo Magnetic Resonance Spectroscopy (MRS), the main methods used allow metabolite concentration quantification using signals having one spectral dimension. This work focuses on the development of in vivo two dimensional correlated MRS in order to increase spectral resolution and quantification precision. The first axis is about the development of a method based on a 2D localized correlation MRS (L-COSY) for brain metabolite exploration. The L-COSY is implemented and studied on a small animal scanner. A dedicated quantification procedure operating in the acquisition domain is described. This latter is based on 1) a strong prior knowledge obtained by quantum mechanically simulate the effect of sequence on metabolite spin systems 2) a model function taking into account the relaxation weighting 3) constraints on the relaxation term linked to the field inhomogeneity effects which are assumed to act the same way on all the spins. Results are given experimentally using metabolites phantoms and through a comparison to other existing 2D MRS method, namely the J-resolved MRS (with the JPRESS sequence) using the Cramer Rao Lower Bounds (CRBs) theory. Although its inherent loss of signal to noise ratio is a disadvantage compared to J-PRESS, L-COSY quantification shows theoretically competitive relative CRBs, and even smaller CRBs for some coupled metabolites (e.g Glutamine or GABA), for an acquisition time similar to JPRESS. Second axis is about the adaptation of the 2D correlation MRS for the in vivo lipid metabolism study in the liver and subcutaneous adipose tissues of obese mice at 7T. This application shows the feasibility of 2D correlated MRS to be acquired on a moving organ and its quantitative relevance for triglyceride quantification and characterization in fatty liver and subcutaneous tissue
Ziegler, Anne. « Développements méthodologiques en spectroscopie RMN proton à une et deux dimensions in vivo : application à l'étude de tumeurs intracérébrales chez le rat ». Grenoble 1, 1992. http://www.theses.fr/1992GRE10131.
Texte intégralBarantin, Laurent. « Développement d'une nouvelle méthode d'estimation des concentrations absolues par spectroscopie RMN in vivo : application à l'étude de la maturation cérébrale ». Tours, 1997. http://www.theses.fr/1997TOUR3307.
Texte intégralThe ERETIC method (Electronic REference To access In vivo Concentrations) allows the absolute quantitation of metabolite concentrations by in vivo NMR spectroscopy (MRS). Ln opposition to other methods, it uses as a reference a synthesised signal produced by an electronic deviee. This signal is therefore simultaneously received by the sample coil. Precise and stable in time, this method allows faster determination of concentrations by comparison between the peaks of interest and the produced peak. The ERETIC method has been applied to the absolute quantitation of metabolites evolution during brain myelination for two neonatal animal models: the piglet and the Beagle puppy. Results show a faster brain myelination for the piglet model, and therefore be used to represent term babies. The beagle puppy model is representative to the preterm newborn
Rémy, Chantal. « Intérêt de la spectroscopie RMN pour l'étude in vivo du métabolisme cérébral dans le cas de pathologies globales et localisées ». Grenoble 1, 1990. http://www.theses.fr/1990GRE10110.
Texte intégralKickler, Nils. « Mesure de glutamate cérébral chez l'homme et le petit animal par spectroscopie RMN in vivo, application à la maladie de Parkinson ». Phd thesis, Université Joseph Fourier (Grenoble), 2006. http://tel.archives-ouvertes.fr/tel-00084812.
Texte intégralWARY, DUDEMAINE CLAIRE. « Spectroscopie rmn du glycogene in vivo et in vitro : nouvelles approches methodologiques et implications pour l'etude du metabolisme glucidique chez l'homme ». Paris 11, 1996. http://www.theses.fr/1996PA112434.
Texte intégralHENRY, PIERRE-GILLES. « Spectroscopie rmn in vivo du cerveau a 3 tesla : developpements methodologiques pour l'etude de modeles animaux de la maladie de huntington ». Paris 6, 2000. http://www.theses.fr/2000PA066210.
Texte intégralLE, JEUNE LE TALLEC NATHALIE. « Exploration pharmacologique des composantes mecaniques et metaboliques de la fatigue musculaire par spectroscopie de rmn du 31p in vivo (doctorat : biol. sante) ». Rennes 1, 1996. http://www.theses.fr/1996REN1B012.
Texte intégralValette, Julien. « Spectroscopie RMN in vivo et métabolisme énergétique cérébral : apport de la pondération en diffusion et de la détection 31P pour l'évaluation du statut énergétique chez le primate ». Paris 6, 2006. http://www.theses.fr/2006PA066094.
Texte intégralMarchadour, Charlotte. « Spectroscopie RMN cérébrale pour l'étude du milieu intracellulaire in vivo : développements méthodologiques pour la diffusion à courtes échelles de temps et pour la mesure du pH en détection 31P ». Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00856086.
Texte intégralRoussel, Tangi. « Développements de méthodes de traitement et d’acquisition du signal pour la Spectroscopie de Résonance Magnétique 2D in vivo ». Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10114/document.
Texte intégralIn vivo proton Magnetic Resonance Spectroscopy (MRS) is a powerful tool for metabolicprofiling because this technique is non-invasive and quantitative. However,conventional localized spectroscopy presents important in vivo metabolic informationthrough overlapped spectral signatures greatly affecting the quantification accuracy.Two-dimensional (2D) MRS, originally developed for analytical chemistry,has great potential to unambiguously distinguish metabolites. Therefore, metabolitequantification is improved allowing accurate estimation of their concentrations. Inthis thesis, the research findings are presented under two main headings. The firstline of research focuses on conventional 2D MRS J-resolved. A J-PRESS sequencewas developed allowing the acquisition of in vivo 2D MRS spectra, which were processedby a dedicated quantification method. Experiments were performed on therat brain using a 7 T imaging system and different sampling strategies were evaluated.The quantification method, specifically developed to handle 2D J-resolved MRSdata quantification in time domain, is based on a strong prior-knowledge. However,2D MRS suffers from long acquisition times due to the collection of numerous incrementsin the indirect dimension. Therefore, the second line of research focuseson the reduction of acquisition time using recently developed methods based on theultrafast NMR concept. A new pulse sequence was designed, allowing 3D localizedultrafast 2D J-resolved spectroscopic acquisition on a 7T small animal imaging system. This breakthrough allows the acquisition of a complete 2D spectrum in a singlescan, resulting in acquisition times of a few seconds
Provent, Peggy. « Imagerie spectroscopique et spectroscopie localisée par RMN du proton in vivo : application à l'étude de la physiopathologie tumorale par cartographie des métabolites et du pH extracellulaire dans un modèle expérimental de gliomes C6 ». Université Joseph Fourier (Grenoble), 2006. http://www.theses.fr/2006GRE10275.
Texte intégralThe aim of this work was to optimize the conditions and the acquisition techniques for spectroscopy and spectroscopic imaging by 1H NMR in vivo in small animals and to apply these techniques to two biological topics. Acquisition conditions have been improved by the use of an automatic correction of B0 field inhomogeneities. Sequences have been improved by the use of an optimized water suppression scheme (VAPOR) and of spiral encoding gradients for short echo time spectroscopic imaging. Extracellular pH (pHe) in tumors is more acidic than in normal tissue. This acidity contributes to tumor proliferation. With a new probe molecule, ISUCA, we used spectroscopic imaging to map the distribution of pHe in C6 gliomas and compared it with the distribution of lactate. The two distributions are not spatially correlated. After hyperglycemia, lactate and protons quantities are globally increased but with a negative spatial correlation. This result suggests that proton are redistributed from sites of glycolysis to membrane pumps. The aim of the second project was to study the role of ammonium in the regulation of glycolysis in the brain. Hyperammonemia increases lactate concentration in the brain. I showed that this increase can be transient, which is a required condition for ammonium to play a physiological role in metabolic interaction between astrocytes and neurones
Chaumeil, Myriam. « Mesure du métabolisme énérgétique cérébral par RMN du 31P in vivo : validation méthodologique multimodale et application à l'étude de la neurodégénérescence ». Paris 11, 2008. http://www.theses.fr/2008PA112365.
Texte intégralNeuroimaging methods have considerably developed over the last decades and offer various non-invasive approaches for measuring cerebral metabolic fluxes. Among these methods, 31P magnetic resonance spectroscopy (MRS) has the particularity to directly measure cerebral ATP synthesis, but is still methodologically challenging. In this context, a multimodal neuroimaging study was performed in order to validate the saturation transfer 31P MRS method as a quantitative measurement of brain ATP synthesis. Glucose consumption (CMRglc), TCA cycle flux (Vtca ) and rate of ATP synthesis (Vatp) were measured in primate monkeys using 18F-FDG PET scan, indirect 13C MRS and saturation transfer 31P MRS, respectively. The consistency of these three fluxes with literature and, more interestingly, one with each other, demonstrated the robustness of saturation transfer 31 P MRS for directly evaluating ATP synthesis in the living brain. The potential of 31P MRS was then evaluated on Huntington's disease patients. Stability of metabolic homeostasis, non-significant decrease in Vatp, and significant increase in cerebral pH were shown in HD patient's brain. The increase in cerebral pH, detected for the first time in MH, was correlated with motor scores. Given these results, in order to assess the precocity of pH variations associated with MH, a study was performed on a rodent chronic model of MH. A significant increase in cerebral pH was detected before any lesions evidence, showing the potentiality of pH measurement as early biomarker of MH
Lotito, Serge. « Applications de la spectroscopie RMN in vivo a l'étude de la neuropharmacologie du système nerveux central du rat : effets métaboliques du cyanure de potassium : pharmacocinétique et pharmacologie du 5-fluoro-uracile ». Grenoble 1, 1990. http://www.theses.fr/1990GRE10140.
Texte intégralBucur, Adriana. « Spectométrie de RMN quantitative in vivo pour la mesure des lipides hépatiques chez l'homme et des métabolites cérébraux chez un modèle murin de neuro-inflammation ». Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10094.
Texte intégralThe proton MRS is a unique non-invasive method to quantitative biochemical exploration of living tissues. The studies presented in this thesis aim to handle each one of the involved steps, from data acquisition to reliable and precise metabolic profile estimation of explored tissues. Protocols for experimental acquisition of in vivo, short echo-time magnetic resonance signals were defined, and optimized for a pre-clinical application (mice) on a 4.7T scanner and for a clinical study at 1.5T. The first study allowed yo measuring cerebral metabolite (N-acetyl-aspartate, choline, creatine, taurine) alterations along time in a murine model of neuro-inflammation on a 4.7T scanner and the second study aimed to measure the total quantity and the composition of liver fat in patients with hepatic steatosis in a clinical environment at 1.5T. Signal processing methods for metabolite and fat contribution estimates, coping with physical signal properties were validated for both studies. These methods are based on non-linear least squares algorithms. Multiple starting values and constraints strategies were successfully validated. The assets and the originality of this project are based on the synergic developments of acquisition protocols and the associated signal processing methods. These developments were designed to enrich the list of the biochemical information non-invasively measured, in order to help medical prognostic and diagnostic
Najac, Chloé. « Spectroscopie RMN du 1H pondérée en diffusion, du 13C et du 17O : développements méthodologiques pour l’étude de la structure et de la fonction cellulaire in vivo ». Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112242/document.
Texte intégralMagnetic Resonance Spectroscopy is a unique tool that allows acquiring brain biochemical profiles and quantifying many cellular parameters in vivo. During this thesis, three different techniques have been developed: (i) 1H diffusion-weighted, (ii) carbone-13 (13C) and (iii) oxygen-17 (17O) NMR spectroscopy to study brain structure and function in vivo. Brain metabolites are cell-specific endogeneous tracers of the intracellular space whose translational diffusion depends on many cellular properties (e.g.: cytosol vicosity and intracellular restriction). Studying the variation of the diffusion coefficient (ADC) as a function of diffusion time (td) allows untangling and quantifying those parameters. In particular, measuring metabolites ADC at long diffusion times gives information about the metabolites compartmentation in cells. In a first study, we measured neuronal and astrocytic metabolites ADC over a large time window (from ~80 ms to ~1 s) in a large voxel in the macaque brain. No dependence of all metabolites ADC on td was observed suggesting that metabolites primarily diffuse in neuronal (dendrites and axons) and astrocytic processes and are not confined inside the cell body and organelles (nucleus, mitochondria). The large size of the voxel, due to low detection sensitivity, did not allow us to study metabolites compartmentation in pure white (WM) and grey matters (GM). Therefore, we performed a new study in the human brain. Results showed that in both WM and GM metabolites diffuse in fiber-like cell structure. Finally, using an even larger time window (up to 2 s) in the macaque brain and analytical models mimicking the cell structure, we estimated the length of neuronal (~110 μm) and astrocytic (~70 μm) processes. ATP (adenosine triphosphate), the main source of energy in the organism, is produced thanks to glucose oxidation inside the mitochondria. 13C NMR spectroscopy is a well-known technique to study brain energy metabolism and can be used to estimate the rate of glucose degradation within the Krebs cycle (VTCA). However, many limitations, concerning data modeling when performing indirect detection or power deposition due to heteronuclear decoupling during direct detection, were encountered on our MRI scanner. Therefore, 17O NMR spectroscopy was developed to quantify the rate of oxygen consumption during oxidative phosphorylation (CMRO2). Methodological and technological developments were necessary and are still ongoing to validate this technique, which has never been used with macaque
Beuste, Christophe. « Analyse modulaire in vivo du contrôle du flux énergétique dans le muscle squelettique de rat par spectroscopie RMN 31P : influence de l'hypoxie et de l'activité physique ». Bordeaux 2, 2007. http://www.theses.fr/2007BOR21483.
Texte intégralWe attempted to describe quantitatively the main kinetic properties of energy metabolism of contracting skeletal muscles of rats in vivo. For that, energy metabolism was defined as a two-module system (supply-demand) connected by energetic intermediate (PCr as representative) assessed in vivo by 31P MRS; such a simplification allowed application of top-down (modular) control analysis to obtain elasticity and control coefficients over a broad spectrum of muscle activities. The main finding of our first study was the shift of control over the contraction from demand at low workloads to supply at high workloads. This was mainly due to the change in sensitivity of supply toward energetic intermediates. Top-down elasticity analysis was used to identify the targets (supply and/or demand) of hypoxic conditioning (6 weeks at 10. 5% O2), hypothyroïdism and chronic physical activity, described as stress generating muscle remodelling. No change in the elasticity of neither supply nor demand toward intermediates were observed: internal properties of the system were unaffected by reported changes in mitochondrial content and/or change in fibre type composition. Once internal properties experimentally obtained, the direct effect of acute hypoxia by measuring the contraction energy flux change was quantified. The main response of energy metabolism to chronic hypoxia was the decrease in sensitivity of supply toward acute decrease in ambient O2. As demonstrated by these applications, the design and set up of our experimental modular approach has the potential to detect a number of physiological effects on energy metabolism of skeletal muscle at a system level of integration
Maurice, Michel. « Participation à la construction d'un spectromètre RMN in vivo : application à la mesure des variations de volume de l'eau au niveau du vertex chez l'homme en microgravité simulée ». Lyon 1, 1991. http://www.theses.fr/1991LYO1T009.
Texte intégralBertoldi, Didier. « Apport méthodologique aux mesures de la perfusion et du métabolisme énergétique par RMN in vivo chez le petit animal et applications à l'exploration fonctionnelle du muscle strié squelettique squelettique ». Paris 6, 2006. http://www.theses.fr/2006PA066521.
Texte intégralBoumezbeur, Fawsi. « Evaluation de la spectroscopie RMN in vivo pour l'exploration de processus neurodégénérarifs : suivi longitudinal de l'atteinte striatale dans le modèle 3NP de la maladie de Huntington chez le primate ». Paris 11, 2005. http://www.theses.fr/2005PA112006.
Texte intégralThe aim of this work was the longitudinal study of striatal alterations associated with chronic 3np treatment in monkeys using a multimodality approach centered on in vivo nmr spectroscopy. First, based on the combination of high resolution mri segmentation and automatic quantitation procedure of 1h press spectra, absolute concentrations of up to 10 brain metabolites have been measured in the striatum of macaque monkeys. Besides, a new method was developed to measure oxidative metabolism. This approach allowed for the simultaneous detection of glutamate c3 and c4 13c-labeling at 3 tesla during an infusion [u-13c6]glucose, using a simple 1h press sequence with an optimal sensitivity. The tricarboxylic acid cycle rate (vtca) was calculated by fitting a metabolic model to these kinetic data. Finally, co-registration of nmr and pet-fdg data was used to achieved direct comparison of vtca and cmrglc measurements. These methodological developments were validated and permitted the determination of control values for the biochemical profile and vtca for 3 monkeys. Then, these developments were applied to characterize striatal degeneration upon 3np intoxication. Immediate alterations of gaba (-64%) and glutamine (-31%) levels were detected with concomitant decrease of vtca (-44%) and cmrglc (-46%). These changes precede the apparition of striatal lesions on mri. These results might reflect an alteration of gabaergic neurotransmission, arguing in favor of a coupling with energy metabolism. The extent to which gabaergic neurotransmission is altered in huntington’s disease remains to be explored
Serres, Sébastien. « Etude par RMN ex vivo chez le rat des interactions métaboliques entre neurones et cellules gliales : rôle du lactate dans le couplage entre métabolisme énergétique et activité cérébrale ». Bordeaux 2, 2005. http://www.theses.fr/2005BOR21225.
Texte intégralWe studied glucose and lactate metabolism in the rat brain under various depressed states using pentobarbital, αchloralose and morphine. Analysis of brain metabolites labelled after infusion with either [1-13C]glucose + lactate or glucose + [3-13C]lactate showed the link between metabolic and electric activities, brain lactate synthesis in astrocytes, and that the contribution of lactate to neuronal metabolism increases with cerebral activation, in agreement with the assumption of the transfer of lactate from astrocytes to neurons during cerebral activation. Also we studied glucose and acetate metabolism in the rat brain under two different levels of cerebral activity. The labelling analysis of brain metabolites after infusion with either [1-13C]glucose + acetate or glucose + [2-13C]acétate showed that pyruvate recycling observed in brain comes from hepatic metabolism, and evidenced the uncoupling between neuronal and astrocytic oxidative metabolism
Loubinoux, Isabelle. « Mise en évidence des potentialités des techniques de RMN "in vivo" pour caractériser la dynamique des évènements métaboliques cérébraux : par spectroscopie 1D et 2D au cours d'une activation cérébrale par imagerie de diffusion et de T2 consécutivement àune ischémie cérébrale ». Paris 11, 1995. http://www.theses.fr/1995PA11T024.
Texte intégralDOAN, BICH-THUY. « Developpement de methodes d'etudes de milieux complexes par spectroscopie de resonance magnetiques nucleaire a deux dimensions. Analyse de polyaromatiques de melanges petroliers par selection de systemes de spins. Mise au point de sequences 2d adaptees a la rmn in vivo ». Paris 11, 1994. http://www.theses.fr/1994PA112088.
Texte intégralNicoli, François. « La spectroscopie de resonance magnetique a haute resolution du liquide cephalo-rachidien humain : une nouvelle methode d'exploration metabolique des pathologies non infectieuses du systeme nerveux central ». Aix-Marseille 2, 1996. http://www.theses.fr/1996AIX22069.
Texte intégralLussier, Jonathan. « Distinction d'isomères de spins par spectroscopie RMN ». Mémoire, Université de Sherbrooke, 2008. http://savoirs.usherbrooke.ca/handle/11143/4791.
Texte intégralBlaise, Pierre. « Etude de lipides par spectroscopie de RMN ». Toulouse, INPT, 1997. http://www.theses.fr/1997INPT007G.
Texte intégralBen, Salem Douraïed. « Spectroscopie RMN du cerveau et maladies vasculaires ». Dijon, 2008. http://www.theses.fr/2008DIJOMU05.
Texte intégralThe microvascular attack of brain has an effect less marked than stroke but it is at the origin of neuronal damage and cognitive deteriorations. The provision of the final vascularization of basal ganglia (BG) particularly exposes them to ischemia. Moreover, the involvement of the BG in many functional and anatomical loops is likely to favor the consequences of these vascular lesions on cognition, and balance & gait. This work aims to present a number of results focusing on hypertension. About 2 cases reports of vascular dementia, we observed, in the absence of stroke, a fall of the NAA in the subcortical gray matter. This observation led us to take an interest to explore ischemic disease by cerebral spectroscopy and to measure NAA ratios in BG and in thalami. The 1st situation is that of the controlateral hemisphere to an ischemic stroke. In this latter study, we showed that the NAA ratio of these “healthy” voxels were in fact dependent on the patient’s cardiovascular risk factors, in particular with the presence of hypertension. In order to better specify the role of hypertension and age as well as relations between the neurochemical abnormalities observed and the cognitive deterioration, it was important to be able to explore a strokeless population. The Three-City(3C) Study, provided us an interesting opportunity. We were able to select a group with no other cardiovascular risk factors except hypertension. From this population, we highlighted links between brain spectroscopy and hypertension. A final publication showed that in this population, mental flexibility and balance gait performances were linked to abnormal morphological and metabolic brain abnormalities
Klein, Marc. « Etude en spectroscopie rmn 31p de la myopathie hypothyroidienne ». Nancy 1, 1990. http://docnum.univ-lorraine.fr/public/SCDMED_T_1990_KLEIN_MARC.pdf.
Texte intégralCatalaa, Isabelle. « Perfusion, diffusion et spectroscopie RMN dans les gliomes cérébraux ». Toulouse 3, 2006. http://www.theses.fr/2006TOU30117.
Texte intégralCerebral gliomas are relatively rare tumors and high grade gliomas have a very poor prognosis. Diffusion, perfusion MRI and spectroscopy NMR give more specific informations than classical morphological MRI sequences. These parameters provide informations that can be related to histology and are consistent with known characteristics that differenciate tumor grade, namely vascularity, vessel permeability, cellularity and necrosis. They can detect metabolic signs of tumoral proliferation, cellular density elevation, and neovascularization in high grades gliomas. Within high grade gliomas, correlations are found between high membrane turnover, increased cell density and high vascularity. The potential of some of these parameters was investigated for predicting survival in patients with newly diagnosed glioblastomas
Moussallieh, François-Marie. « La métabolomique par spectroscopie RMN HRMAS appliquée en cancerologie ». Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAF058.
Texte intégralCancer, one of the most frequent pathologies among the population, has still an important morbidity-mortality rate all sex confounded, despite the important diagnostical and therapeutical progresses achieved. From a diagnostical point of view, in a so called “Systems Biology approach”, as a complement of the gold standard histopathological study, some new techniques have been developed for the characterization of metabolic profiles (Metabolomics) of tissular samples pathological or not, among which HRMAS NMR Spectroscopy. After some brief theoretical considerations and after reporting the applications of this technique in Cancerology, we exposed the different steps of the protocol to design in order to consider its implementation in a hospital set up. All the results presented allow considering the use of this technique in a clinical routine. Nevertheless, it is necessary to validate the robustness of the statistical models built and to confirm these results on much larger cohorts of samples. Some technical, analytical and statistical developments are also needed
Robert, Olivier. « RMN et extraits tissulaires cérébraux : RMN du proton et gradation des tumeurs cérébrales primitives humaines, RMN du proton et modifications métaboliques chez les brebis atteintes de tremblante, RMN du fluor et métabolisme du 5-fluorouracile dans les tumeurs gliales chez le rat ». Toulouse 3, 2004. http://www.theses.fr/2004TOU30177.
Texte intégralIn this manuscript we used Nuclear Magnetic Resonance spectroscopy () in vitro for the study of brain samples in three different cases. The first part, which forms the principal work of this manuscript, consists of the analysis of human cerebral tissue extracts by 1H NMR. We established metabolic profiles, characteristic of cerebral pathologies. In the second part, we used 1H-NMR to compare brain extracts of healthy and scrapie sheeps. In this case, we also established metabolic profiles for this pathology in two brain areas. In the last part, we used 19F-NMR for the study of 5-fluorouracile (5-FU) metabolisation in experimental rat gliomas
Castro, Pascal. « Etude et développement d'une sonde RMN hyperbare : Exemples d'applications ». Montpellier 1, 1998. http://www.theses.fr/1998MON13503.
Texte intégralLilly, Thankamony Aany Sofia. « Synergie RMN ET RPE : développement de la DNP-RMN pour la caractérisation des matériaux inorganiques et hybrides ». Electronic Thesis or Diss., Lille 1, 2014. http://www.theses.fr/2014LIL10002.
Texte intégralMy PhD work focused on two topics: (i) the extension of Dynamic Nuclear Polarization (DNP) to inorganic and hybrid materials and (ii) the development of advanced NMR methods to probe the atomic-level structure of solids. In the field of DNP NMR, we aim at demonstrating how the DNP sensitivity enhancement can provide new insights into the structure of inorganic and hybrid materials. We have introduced a solvent-free DNP alternative to post-synthesis impregnation which permits fast polarization build-up. We have also shown that DNP is feasible for nanoparticles dispersed in a frozen solution containing exogenous radicals. The complementarity of DNP cross-polarization (CP) and direct polarization (DP) has been demonstrated. Furthermore, we have demonstrated that the DNP sensitivity enhancement allows probing 27Al-27Al proximities near the surface of mesoporous alumina and 27Al-13C proximities in the microporous metal organic framework MIL-100(Al). It was also shown that in the case of functionalized mesoporous silica nanoparticles loaded with surfactants, the DNP CP-MAS can be used to enhance NMR signals of 13C and 29Si nuclei located at several hundred nanometers from the polarizing agent. In addition, we have analyzed the different contributions to the sensitivity enhancement in 13C and 29Si CP-MAS experiments of functionalized mesoporous silica nanoparticles. My PhD has also led to the development of conventional NMR methods, including (i) tunable homonuclear dipolar decoupling for 1H high-resolution NMR and (ii) novel cross polarization (CP) pulse sequence to probe proximities between half-integer quadrupolar isotopes
Cuny, Marion. « Authenticite des produits agroalimentaires par spectroscopie rmn 1h et outils chimiometriques ». Phd thesis, AgroParisTech, 2008. http://pastel.archives-ouvertes.fr/pastel-00003745.
Texte intégralCuny, Marion. « Authenticité des produits agroalimentaires par spectroscopie RMN 1H et outils chimiométriques ». Paris, AgroParisTech, 2008. http://www.theses.fr/2008AGPT0017.
Texte intégral1H NMR spectroscopy is widely used as an analytical method in different sectors. Its number of applications in the area of food and beverage authenticity is growing. However, the multivariate analysis of the type of data obtained from an NMR spectrum is still not as developed as in Near Infrared spectroscopy. In this work, different chemometric methods have been applied to 1H NMR data in order to assess the potential of the combined techniques to authenticate food and beverages. First, we have demonstrated that Independent Component Analysis (ICA) was better adapted to the analysis of a 1H NMR spectrum than the commonly used Principal Component Analysis (PCA). Indeed, by its very nature, ICA aims at recovering pure sources from mixed signals. Applied to the spectra, it was shown that it is possible to extract certain component signals, such as the naringin signal from the spectra of a mixture of orange and grapefruit juices. Different pre-treatments were then tested. Data warping has been found to be useful when the data shows variation in chemical shifts. In addition, as the data also varied considerably in intensity along the spectrum, a logarithmic transformation was performed to produce unbiased results when using other chemometric tools such as PCA and ICA. Finally, different approaches were investigated to select variables in the spectrum. The first approach was based on criteria related to the variables themselves, such as the total variance and covariance in the Clustering of Variables (CLV) function. The second type of method involved the selection of contiguous variables to take into account the relation between variables in a signal. Interval_PLS (iPLS) was used as a reference to compare other more recently developed methods: Evolving Windows Zone Selection and Interval-PLS_Cluster. The variable selection techniques used were to highlight known authenticity markers of orange and grapefruit juices: flavonoids hesperidin and naringin that are measured in the standard HPLC method IFU 58. In the case of the balsamic vinegar dataset, the selected zones contained the signal of compounds linked to the product's aging process that differentiate traditional balsamic vinegar from its cheaper, more commonly used counterpart. In the example based on different types of yoghurts, the variable selection procedures focused on 6 certain aroma compounds and solvents used as flavour carriers. These were used to differentiate the type of yoghurts: flavoured, with fruit, with pulp and at different concentrations. Through these different applications, this study has shown the importance of using appropriate tools for spectral analysis tools that take into account the specificity of 1H NMR spectroscopy compared to other spectroscopic methods: variation in intensities along the spectrum, the size of the dataset, and redundant information