Dissertations / Theses on the topic 'Muscles Magnetic resonance imaging'
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Manners, David Neil. "Magnetic resonance imaging and magnetic resonance spectroscopy of skeletal muscle." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269250.
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Shaubari, Ezak Fadzrin Ahmad. "Automatic segmentation of the human thigh muscles in magnetic resonance imaging." Thesis, Manchester Metropolitan University, 2018. http://e-space.mmu.ac.uk/621007/.
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Advances in magnetic resonance imaging (MRI) and analysis techniques have improved diagnosis and patient treatment pathways. Typically, image analysis requires substantial technical and medical expertise and MR images can su↵er from artefacts, echo and intensity inhomogeneity due to gradient pulse eddy currents and inherent e↵ects of pulse radiation on MRI radio frequency (RF) coils that complicates the analysis. Processing and analysing serial sections of MRI scans to measure tissue volume is an additional challenge as the shapes and the borders between neighbouring tissues change significantly by anatomical location. Medical imaging solutions are needed to avoid laborious manual segmentation of specified regions of interest (ROI) and operator errors. The work set out in this thesis has addressed this challenge with a specific focus on skeletal muscle segmentation of the thigh. The aim was to develop an MRI segmentation framework for the quadriceps muscles, femur and bone marrow. Four contributions of this research include: (1) the development of a semi-automatic segmentation framework for a single transverse-plane image; (2) automatic segmentation of a single transverseplane image; (3) the automatic segmentation of multiple contiguous transverse-plane images from a full MRI thigh scan; and (4) the use of deep learning for MRI thigh quadriceps segmentation. Novel image processing, statistical analysis and machine learning algorithms were developed for all solutions and they were compared against current gold-standard manual segmentation. Frameworks (1) and (3) require minimal input from the user to delineate the muscle border. Overall, the frameworks in (1), (2) and (3) o↵er very good output performance, with respective framework's mean segmentation accuracy by JSI and processing time of: (1) 0.95 and 17 sec; (2) 0.85 and 22 sec; and (3) 0.93 and 3 sec. For the framework in (4), the ImageNet trained model was customized by replacing the fully-connected layers in its architecture to convolutional layers (hence the name of Fully Convolutional Network (FCN)) and the pre-trained model was transferred for the ROI segmentation task. With the implementation of post-processing for image filtering and morphology to the segmented ROI, we have successfully accomplished a new benchmark for thigh MRI analysis. The mean accuracy and processing time with this framework are 0.9502 (by JSI ) and 0.117 sec per image, respectively.
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Lam, Ernest W. N. "Human masseter muscle studies by magnetic resonance." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30005.
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The human masseter muscle is a structurally complex jaw elevator with the capability of generating high, multidirectional forces. The invasiveness of current anatomical and physiological methods has, however, limited both the number and scope of studies of human masseter muscle structure and function. Therefore the aim of this work was to apply in vivo magnetic resonance (MR) techniques to elucidate the three-dimensional internal architecture of the human masseter muscle and its metabolic response to exercise in order to gain a better understanding of the jaw muscles in health and disease.
In the first of these experiments, five adult subjects were selected and examined using cephalometric radiography, magnetic resonance imaging (MRI) and three-dimensional rotational and reconstructive computer graphics to describe the organization of tendon planes within the masseter muscle. Planar quadrilaterals representing putative tendon planes were fitted to the surfaces of the three-dimensional muscle reconstructions, and these were related to the mid-sagittal plane in the coronal and axial views. To confirm whether putative planes disclosed by MRI represented true anatomic entities, a fresh human cadaver head was imaged by MRI and then cryosectioned at millimetre intervals. Planar sections through the reconstructed muscle generated from the cadaver cryosections were correlated with the actual MR images in the same planes. Tendon plane angulation appeared to be related to ramal length and lower face height measured cephalometrically. In the axial view, the tendon planes appeared roughly to follow the angulations of the zygomatic arch and the lateral face of the mandibular ramus. Our results suggest that the angulation of tendon planes, and possibly pennation angles are different depending on the viewing angle, and infer that muscle fibres inserting on either side of a central tendon may need to develop different tensile forces if translation is to occur directly along the tendon axis.
In the second, 31P magnetic resonance spectroscopy (MRS) was utilized to examine the masseter muscles of six adult males at rest and performing stereotyped isometric clenching exercises. 31P MR spectra were acquired from three locations within the muscle
using a 2cm by 3cm, single-turn, copper receiver coil. The spectra were quantified on the
basis of relative peak area and position. The organic phosphate (Pi) to creatine phosphate
(PCr) ratio (Pi/PCr), which has been shown to be proportional to free ADP concentration
and hence, the metabolic activity, as well as the normalized Pi concentration ([Pi]) and pH,
were calculated for each site and exercise. The mean resting Pi/PCr ratio and [Pi] were
greater for the deep part of the muscle than for the superficial and intermediate parts. These
differences were significant to p<0.01. The mean pH however, was similar in all parts of the
muscle at rest. During exercise, a significant increase in mean Pi/PCr was found in the
superficial and intermediate parts of the muscle. Both these differences were significant to
p<0.05. An accompanying decrease in mean pH was observed in all parts of the muscle
during exercise. In the superficial part of the muscle, this decrease was significant to the
p<0.05 level, and in the deep part, the decrease was significant to the p<0.001 level. No
significant differences were found for these parameters between left and right molar
clenching. These results suggest that metabolic activity may be monitored in the masseter
muscle using 31P MR spectroscopy and that task-dependent and regional variations in metabolic activity may be demonstrated both at rest and during exercise. They are promising enough to encourage future studies of muscle metabolism in subjects with jaw muscle disorders.
These experiments demonstrate the novel application of magnetic resonance techniques for studying craniomandibular morphology and function non-invasively. Collectively, they reveal the anatomical and functional heterogeneity which exist in the human masseter muscle.Medicine, Faculty of
Biochemistry and Molecular Biology, Department of
Graduate
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Kaltwasser, Sebastian. "Volumetric Manganese Enhanced Magnetic Resonance Imaging in mice (mus musculus)." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-141742.
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Yang, X. (Xiaojiang). "Magnetic resonance imaging of the lateral pterygoid muscle in temporomandibular disorders." Doctoral thesis, University of Oulu, 2002. http://urn.fi/urn:isbn:9514266439.
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Abstract
The fact that the lateral pterygoid muscle (LPM) and related symptoms play an important role in
temporomandibular disorders (TMD) is widely recognized. In the study reported here, the LPM was
investigated by magnetic resonance imaging (MRI) of patients with TMD. The visibility of the LPM in MRI
with different projections was analyzed and a new imaging projection, condyle-the lateral pterygoid muscle
projection (CLPM), for the LPM in MRI was introduced. Normal and abnormal findings of the LPM was compared
with clinical symptoms of TMD.
Compared with sagittal imaging of temporomandibular joint (TMJ), CLPM images and most of the oblique
sagittal imaging were able to show the LPM clearly. Hypertrophy, atrophy and contracture of the LPM were
found in TMJs either with disc in normal position or with disc displacements. Pathological changes of the
superior belly and hypertrophy of the inferior belly combined with various pathological changes of the
superior belly were the most frequently observed abnormal imaging findings of the LPM in TMD. The
pathological changes of the LPM were associated with the main clinical symptoms of TMD. In patients with
symptomatic condyle hypermobility, the pathological changes of the LPM and related symptoms were associated
with the clinical symptoms of TMJs with disc in normal position. The imaging abnormalities of the LPM were
common in TMJs with disc displacements and seemed to be fewer in condyle hypomobility cases in TMJs with
anterior disc displacement with non-reduction (ADDnr). However, normal imaging of the LPM was also found in
TMJs with severe osteoarthritic changes and disc displacement.
The recognition of muscle alterations may lead to a more specific diagnosis and improve the
understanding
of the clinical symptoms and disease pathophysiology of TMD.
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Jack, James. "Computer aided analysis of inflammatory muscle disease using magnetic resonance imaging." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/19579.
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Inflammatory muscle disease (myositis) is characterised by inflammation and a gradual increase in muscle weakness. Diagnosis typically requires a range of clinical tests, including magnetic resonance imaging of the thigh muscles to assess the disease severity. In the past, this has been measured by manually counting the number of muscles affected. In this work, a computer-aided analysis of inflammatory muscle disease is presented to help doctors diagnose and monitor the disease. Methods to quantify the level of oedema and fat infiltration from magnetic resonance scans are proposed and the disease quantities determined are shown to have positive correlation against expert medical opinion. The methods have been designed and tested on a database of clinically acquired T1 and STIR sequences, and are proven to be robust despite suboptimal image quality. General background information is first introduced, giving an overview of the medical, technical, and theoretical topics necessary to understand the problem domain. Next, a detailed introduction to the physics of magnetic resonance imaging is given. A review of important literature from similar and related domains is presented, with valuable insights that are utilised at a later stage. Scans are carefully pre-processed to bring all slices in to a common frame of reference and the methods to quantify the level of oedema and fat infiltration are defined and shown to have good positive correlation with expert medical opinion. A number of validation tests are performed with re-scanned subjects to indicate the level of repeatability. The disease quantities, together with statistical features from the T1-STIR joint histogram, are used for automatic classification of the disease severity. Automatic classification is shown to be successful on out of sample data for both the oedema and fat infiltration problems.
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Salvati, Roberto. "Development of Magnetic Resonance Imaging (MRI) methods for in vivo quantification of lipids in preclinical models." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1B026/document.
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L'obésité est associée à une augmentation de la morbidité et de la mortalité liée à de nombreuses maladies, y compris le diabète de type 2, l'hypertension et des pathologies hépatiques menant à une surcharge lipidique d’origine non alcoolique. Récemment, l’imagerie par résonance magnétique (IRM) est devenue la méthode de choix pour la quantification non invasive de la graisse. Dans cette thèse, les méthodes d'IRM ont été étudiées sur un scanner préclinique de 4.7T in vitro (fantômes MR) et in vivo (souris). Deux algorithmes de quantifications de la graisse -la méthode de Dixon et l’algorithme IDEAL- ont été considérés. Les performances de l'algorithme IDEAL ont été analysées en fonction de propriétés des tissus (T2*, fraction de graisse et modèle spectral de la graisse), de paramètres d'acquisition IRM (temps d’écho, nombre d'échos) et de paramètres expérimentaux (SNR et carte de champ). Sur les fantômes, l'approche standard single-T2* IDEAL a montré certaines limites qui pourraient être surmontées en optimisant le nombre d'échos. Une nouvelle méthode, pour déterminer les valeurs de vérité terrain pour T2* de l'eau et pour T2* de la graisse, a été proposée. Pour les mesures in vivo, différentes analyses ont été effectuées en utilisant l'algorithme IDEAL sur le foie et les muscles. L'analyse statistique sur les mesures de ROI a montré que le choix optimal du nombre d'échos est égal à trois pour la quantification de la graisse et six ou plus pour la quantification du T2*. Les valeurs de la fraction de graisse, calculées avec l'algorithme IDEAL, étaient statistiquement comparables aux valeurs obtenues avec la méthode de Dixon. Enfin, un procédé pour générer des signaux de référence mimant les systèmes eau-graisse (Fat Virtual Phantom MRI), sans l'aide d'objets physiques, a été proposé. Ces fantômes virtuels, qui présentent des caractéristiques de bruit réalistes, représentent une alternative intéressante aux fantômes physiques pour fournir un signal de référence dans les mesures IRMObesity is associated with increased morbidity and mortality linked to many diseases, including type 2 diabetes, hypertension and disease nonalcoholic fatty liver. Recently, 1H magnetic resonance imaging (MRI) has emerged as the method of choice for non-invasive fat quantification. In this thesis, MRI methodologies were investigated for in vitro (MR phantoms) and in vivo (mice) measurements on a 4.7T preclinical scanner. Two algorithms of fat quantifications – the Dixon’s method and IDEAL algorithm – were considered. The performances of the IDEAL algorithm were analyzed as a function of tissue properties (T2*, fat fraction and fat spectral model), MRI acquisition parameters (echo times, number of echoes) and experimental parameters (SNR and field map). In phantoms, the standard approach of single-T2* IDEAL showed some limitations that could be overcome by optimizing the number of echoes. A novel method to determine the ground truth values of T2* of water and T2* of fat was here proposed. For in vivo measurements, different analyses were performed using the IDEAL algorithm in liver and muscle. Statistical analysis on ROI measurements showed that the optimal choice of the number of echoes was equal to three for fat quantification and six or more for T2* quantification. The fat fraction values, calculated with IDEAL algorithm, were statistically similar to the values obtained with Dixon’s method. Finally, a method for generating reference signals mimicking fat-water systems (Fat Virtual Phantom MRI), without using physical objects, was proposed. These virtual phantoms, which display realistic noise characteristics, represent an attractive alternative to physical phantoms for providing a reference signal in MRI measurements
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Fan, Ang-Xiao. "Geometric and numerical modeling of facial mimics derived from Magnetic Resonance Imaging (MRI) using Finite Element Method (FEM)." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2307.
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Le visage humain joue un rôle important dans la communication interpersonnelle. La dysfonction du visage ou le défigurement due aux traumatismes ou pathologies peuvent entraver les activités sociales normales. Le traitement chirurgical est souvent nécessaire. De nos jours, le résultat du traitement chirurgical et l’état d’établissement ne sont estimé qu’avec les méthodes qualitatives telles que l’observation visuelle et la palpation. Dans l’attente de fournir des critères quantitatifs, cette thèse a pour l’objectif de modéliser la mimique faciale utilisant MEF (Méthode d’Éléments Finis) sur la base des données d’IRM (Imagerie par Résonance Magnétique). Un modèle sujet-spécifique du visage a été construit sur la base de la segmentation des données IRM ; il contient des parties osseuses, muscles de la mimique (p.ex. le muscle grand zygomatique), les tissues mous sous-cutanées et la peau. L’identification des tissus mous biologiques a été réalisée via des essais de traction bi-axiale et la modélisation numérique. Ensuite, le modèle géométrique a été maillé pour effectuer des calculs EF simulant trois mouvements mimiques du visage (sourire, prononciation du son « Pou » et « O »). Les muscles ont été modélisés comme un matériau quasi-incompressible, transversalement isotrope et hyperélastique, avec la capacité d’activation. Des informations pertinentes (p.ex. l’amplitude de contraction du muscle) utilisées dans la simulation ont été extraites de la mesure des données d’IRM. Il est à noter que les mêmes données expérimentales d’IRM telles qu’ils ont utilisées dans la modélisation ont été prises comme une référence de validation pour les résultats de simulation. Cette étude peut être appliquée cliniquement dans l’évaluation du traitement faciale et le rétablissement postopérativeHuman face plays an important role interpersonal communication. Facial dysfunction or disfigurement due to trauma or pathologies may impede normal social activities. Surgical treatment is often necessary. Nowadays, treatment outcome and rehabilitation condition are estimated only by qualitative methods, such as visual observation and palpation. In expectation of providing quantitative criteria, this thesis proposes to model facial mimics using FEM (Finite Element Method) on the basis of MRI (Magnetic Resonance Imaging) data. A subject-specific face model was reconstructed based on segmentation of MRI data; it contains bony parts, mimic muscles (e.g. zygomaticus major muscle), subcutaneous soft tissues and skin. Identification of biological soft tissues was conducted through bi-axial tension tests and numerical modeling. Then the geometric model was meshed to conduct FE calculations simulating three facial mimic movements (smile, pronunciation of sound “Pou” and “O”). Muscle was modeled as quasi-incompressible, transversely-isotropic, hyperelastic material, with activation ability. Relevant information (e.g. contraction amplitude of muscle) used in simulation was extracted from measurement of MRI data. It is to be noted that the same experimental MRI data as used in modeling was taken as validation reference for simulation results. This study can be applied clinically in evaluation of facial treatment andpostoperative recovery
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Kaltwasser, Sebastian F. [Verfasser], and Carsten [Akademischer Betreuer] Wotjak. "Volumetric Manganese Enhanced Magnetic Resonance Imaging in mice (mus musculus) / Sebastian Kaltwasser. Betreuer: Carsten Wotjak." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/1021307750/34.
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Tucker, David C. "Metabolic factors influencing fatigue during a 90 second maximum muscle contraction." Birmingham, Ala. : University of Alabama at Birmingham, 2009. https://www.mhsl.uab.edu/dt/2009m/tucker.pdf.
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Mitsiopoulos, Nikolaos. "Validation of magnetic resonance imaging and computerized tomography measurement of skeletal muscle by comparison to human cadaver." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22363.pdf.
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Al, Gohani Fahad. "Comparison of peripheral quantitative computed tomography and magnetic resonance imaging for tissue characterisation in the gastrocnemius muscle." Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/102032/.
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Rupture of the medial head of the gastrocnemius muscle (GM) is a common injury of the calf muscles. Magnetic resonance imaging (MRI) and ultrasound (US) are the medical imaging modalities that are usually used to assess such injuries. Texture analysis is a digital image processing technique that quantifies the relationship between pixel intensities (grey levels) and pixel positions. Texture can reveal valuable information that cannot be perceived by the naked eye. Dedicated image processing software is required to extract texture parameters. Texture analysis has been implemented for medical imaging modalities such as MRI, US and computed tomography (CT) for the evaluation sports muscle injury. Peripheral quantitative tomography (pQCT) is an adaptation of conventional CT. In this project, texture analysis was implemented on MRI and pQCT images of the gastrocnemius muscle (GM). MRI is an expensive technique that requires specialised facilities. Conversely, pQCT utilises a small-bore, low-dose X-ray scanner, which is portable and less costly than MRI. It has traditionally been used mainly for bone analysis. The aim of this study was to assess the suitability of pQCT for GM tissue characterisation using texture analysis compared with MRI. The study is novel in that it is the first to apply texture analysis to GM images using pQCT Texture analysis was done on image data acquired from MRI (GE, 1.5T) and pQCT (Stratec XCT 2000) in a group of healthy human subjects and an injured subject. A water phantom was also scanned with pQCT. An existing standard imaging protocol was observed for MRI acquisition, while pQCT image acquisition parameters were explored and optimised to yield a standard protocol. The pQCT scanner was shown to be capable of acquiring calf muscle images and distinguishing calf muscle boundaries. Texture parameters (grey level, variance, skewness, kurtosis, co-occurrence matrix, run length matrix, gradient, autoregressive (AR) model and wavelet transform) were extracted from the acquired images. The repeatability of these quantities for pQCT in a healthy human subject and a water phantom was assessed by calculating the coefficient of variation (%CV). The effect of pQCT parameters (scan speed and pixel size) was tested using multiple variate II analysis of variance (MANOVA). The effect of region of interest (ROI) area and anatomical position were evaluated using simple linear regression. The t-test was used to compare the mean values of the texture features in the right and left leg for both MRI and pQCT in a group of healthy human subjects. Neither MRI nor pQCT showed significant differences between the two legs for any of the texture features. In addition, there was no significant difference between the two modalities for the AR model and wavelet transform texture parameters. Reference ranges for the medial head of the GM were defined for both modalities. A study of a single injured subject revealed that the values of the AR model texture parameter fell outside the reference ranges for both MRI and pQCT, and so the AR model was identified as the most sensitive texture parameter for distinguishing injured from uninjured GM. The principal conclusion from this work is that pQCT has the potential to be used for imaging the gastrocnemius muscle and that GM images from both MRI and pQCT scanners can be objectively characterised by texture analysis. In addition, the autoregressive model texture parameter may be the most appropriate for muscle characterisation.
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Karkouri, Jabrane. "Exploiting sparse spectrum to accelerate spiral magnetic resonance spectroscopic imaging : method, simulation and applications to the functional exploration of skeletal muscle." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1295.
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La quantification du métabolisme musculaire énergétique et de la capacité mitochondriale est d'un intérêt crucial pour étudier les troubles musculaires, les maladies métaboliques ou cardiovasculaires comme la myopathie mitochondriale, le diabète ou les maladies artérielles périphériques. La spectroscopie 31P est un moyen non invasif de monitorer le métabolisme énergétique et les concentrations dynamiques de métabolites phosphorylés pendant ou après un exercice et fournit des informations sur la capacité mitochondriale et oxydative du muscle squelettique. L'évaluation du métabolisme énergétique par spectroscopie 31P peut se faire par spectroscopie non localisée, spectroscopie monovoxel et imagerie spectroscopique par résonance magnétique (MRSI). Dans la pratique clinique, la spectroscopie 31P non localisée est généralement réalisée, ce qui empêche de mesurer les informations métaboliques de différents muscles individuellement, et une information moyenne résultant du muscle entier est collectée en une seule fois par la bobine de surface utilisée pour l'expérience. L'utilisation de la spectroscopie 31P localisée permettrait d'accéder à des informations spatialement résolues et de motiver le développement de nouvelles séquences intégrant les développements techniques les plus avancés. L'imagerie spectroscopique par résonance magnétique (ISRM) disponible dans les systèmes cliniques a un temps d'acquisition très long qui limite son utilisation clinique à l'acquisition statique, alors que ce qui est d’intérêt est essentiellement la capacité à mesurer dynamiquement les variations de concentration des métabolites phosphorylés au cours d’un protocole d'exercice. Les développements méthodologiques sur l’ISRM réalisés dans le cadre de cette thèse, se sont attaqués précisément à réduire le temps d'acquisition, en vue d’applications cliniques. Une méthode d'acquisition ISRM rapide a donc été développée, impliquant un échantillonnage non cartésien dans l'espace k (échantillonnage en spirale), couplé à un sous-échantillonnage intelligent de la dimension temporelle, exploitant la connaissance a priori de la parcimonie du support spectral et une estimation par moindres carrés pour la reconstruction du signal. Cette méthode a été validée à l'aide de simulations et mise en œuvre dans un système IRM, optimisée puis testée in vivo sur le muscle du mollet pour des applications ISRM 1H et 31P. Des applications dynamiques 31P ont également été réalisées à 3T et l'utilisation de la séquence sous-échantillonnée CSI spiral développée a montré qu'elle était capable de révéler les changements dynamiques attendus dans le PCr. La quantification du signal nous a permis en outre d'accéder à la capacité mitochondriale, avec une résolution temporelle dynamique deux fois supérieure à celle du cas ISRM spiral avec échantillonnage régulier, et une résolution temporelle similaire à celle de l’ISRM non localisée utilisée conventionnellement. Ces développements sont d'un intérêt crucial pour une évaluation spatialement résolue de la capacité mitochondriale au sein de différents muscles ; c'est-à-dire pour mettre en évidence des altérations musculaires individuelles liées à des dommages spécifiques ou des différences de consommation d'énergie entre les différents chefs musculaires pendant l'exercice. Des améliorations de séquence sur la spectroscopie 31P localisée 1D ont également été intégrées dans un protocole clinique en cours, afin, à terme, d’appliquer les développements de séquence réalisés pendant cette thèse à un contexte clinique. D'abord testé sur des volontaires sains pour la reproductibilité, le protocole implique des patients qui souffrent d'artériopathie de la jambe inférieure. L'objectif était d'évaluer la capacité mitochondriale de ces patients avant et après une revascularisation de l'artère endommagée. Les résultats ont montré une amélioration significative de la capacité mitochondriale après revascularisationQuantifying energetic muscular metabolism and mitochondrial capacity are of crucial interest to reveal muscular disorders, metabolic diseases or cardiovascular diseases like mitochondrial myopathy, diabetes or peripheral arthery diseases. 31P spectroscopy is a non-invasive way to monitor energetic metabolism and dynamic concentrations of 31P during exercise or after during recovery, and provides informations on mitochondrial and oxidative capacity. The assessment of energetic metabolism via 31P spectroscopy can be done with non-localized spectroscopy, single voxel selection spectroscopy and Magnetic Resonance Spectroscopic Imaging (MRSI). In clinical practice, mostly non localized 31P spectroscopy is done, preventing metabolic information from different individual muscles to be measured, but an average information resulting from the whole muscle and collected at once by the surface coil used for the experiment. The use of localized 31P spectroscopy would enable to access spatially resolved information and motivate the development of new home made sequences integrating the most advanced technical developments. Magnetic resonance Chemical shift Spectroscopic Imaging (CSI) available in clinical systems have very long acquisition time that limits their clinical use to static acquisition, while this is essentially the capacity to measure 31P dynamically during an exercise protocol that is of interest. The methodological developments on MRSI realized In the context of this thesis, aimed precisely at reducing the acquisition time and in view of some clinical applications. A fast MRSI acquisition method has thus been developed involving a non-Cartesian k-space Sampling (spiral sampling), coupled to a smart under-sampling of the temporal dimension, exploiting a priori known spectral support and a least-square estimation for signal reconstruction. This method has been validated using simulations, and implemented in a MR scanner, optimized and then tested in vivo on the calf muscle for 1H and 31P MRSI applications. Dynamic 31P applications were also performed at 3T and the use of the under-sampled CSI_spiral MRSI developed sequence has been shown to adequately reveal the expected dynamic changes in PCr. Quantification of the signal further enable us to access mitochondrial capacity, with a twice higher dynamic temporal resolution compared to the fully sampled CSI_spiral MRSI case, and similar temporal resolution as the non-localized classically used MRS sequence. Those developments are of crucial interest for a spatially resolved assessment of mitochondrial capacity within different muscles, i.e. to point out individual muscle alterations related to specific damages or differences between muscle energy consumption during the exercise. Sequence improvements on 1D localized 31P spectroscopy were also integrated in the clinical sequence and used in an on-going clinical protocol; in order, in the long term, to apply the sequence developments carried out during this thesis to a clinical context. First tested on safe volunteers for reproducibility, the protocol involves patients that suffer from lower leg arteriopathy. The objective was to assess mitochondrial capacity of those patients before and after a revascularization of the damaged artery. Results showed significant improvement in mitochondrial capacity after revascularization
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Jiang, Zhiguo. "Altered Cortico-cortical Brain Connectivity During Muscle Fatigue." Cleveland State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=csu1264108010.
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Hiepe, Patrick [Verfasser], Jens [Akademischer Betreuer] Haueisen, Jürgen R. Gutachter] Reichenbach, and Fritz [Gutachter] [Schick. "Magnetic resonance imaging of muscle structure and function / Patrick Hiepe ; Gutachter: Jürgen R. Reichenbach, Fritz Schick ; Betreuer: Jens Haueisen." Ilmenau : TU Ilmenau, 2017. http://d-nb.info/1178141403/34.
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Kelley, Joshua Jed. "Maintaining Skeletal Muscle Through Eccentric Exercise after Bariatric Surgery: A Randomized Controlled Trial." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7742.
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Purpose: To investigate the effects of eccentric exercise on lower body skeletal muscle mass during rapid body mass loss induced by bariatric surgery. Methods: All participants began 6 to 8 weeks after undergoing Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Skeletal muscle mass (SMM) in the lower body was measured via magnetic resonance imaging (MRI); additional exercise measurements included muscular strength and functional capacity. Quality of life was measured using Short Form 36 (SF-36). Nineteen females (age = 37.6 ± 9.8 yr, height = 164.4 ± 7.2 cm, mass = 106.9 ± 15.6 kg) were randomly assigned to 1 of 3 groups: eccentric exercise (EEX; n = 6), concentric exercise (CEX; n = 7), or standard-of-care control (CON; n = 6). Exercise groups performed 30-minute lower-body exercise sessions 3 times per week for 16 weeks. Each month the exercise tests were evaluated. At the end of 16 weeks, all participants performed the final exercise tests, received a final MRI scan, and completed the SF-36 questionnaire. Results: Thirteen individuals completed the study. All groups lost mass: CON: 21.4 ± 3.7 kg (p < 0.001), CEX: 19.9 ± 4.0 kg (p = 0.001), and EEX: 21.8 ± 3.3 kg (p < 0.001). SMM decreased in all groups: CON: 0.77 ± 0.5 kg (p = 0.18), CEX: 1.19 ± 0.6 kg (p = 0.06), and EEX: 0.90 ± 0.5 kg (p = 0.09). The skeletal muscle loss in percent of total mass loss was 3.7 ± 4.1%. All measures of muscular strength showed no difference, except for a small decrease in dynamic (60°·sec-1) strength in the eccentric group. Functional capacity and physical quality of life increased significantly in all groups (p < 0.05). Conclusion: SMM loss still occurred in the lower body regardless of resistance training, but the loss was less than what was previously documented. Improved postsurgical functional capacity and physical quality of life may be due to a reduction in fat mass and maintenance of muscular strength during the period of rapid mass loss.
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Bourne, Matthew N. "Hamstring strain injury: The role of strength and voluntary activation." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/98262/4/Matthew_Bourne_Thesis.pdf.
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Hamstring strain injuries are endemic in running-based sports, often resulting in substantial performance decrements and costing professional sporting organisations millions of dollars each year. This program of research has contributed new knowledge relating to factors which may predispose to, and manifest as a result of hamstring injury, while also providing novel data which may be used to inform injury prevention and rehabilitation practices.
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Messer, Daniel J. "Anterior cruciate ligament reconstruction and the hamstrings: Implications for injury prevention and rehabilitation." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/118578/2/Daniel_Messer_Thesis.pdf.
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Both anterior cruciate ligament and hamstring strain injuries account for a significant amount of lost time in a range of football codes. This program of research has contributed new knowledge relating to the maladaptations which occur after anterior cruciate ligament injury and subsequent reconstruction, while also providing novel data which may be used to form decisions regarding exercise selection in anterior cruciate ligament and hamstring strain injury prevention and rehabilitation programs.
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Shin, David Dongsuk. "Study of structure and function in the human triceps surae muscle-tendon complex under normal and atrophic states using magnetic resonance phase contrast imaging." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1779690311&sid=5&Fmt=2&clientId=48051&RQT=309&VName=PQD.
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Nygren, Anders T. "Response of human skeletal muscle to chronic and acute exercise and ischemia : muscle dimensions, tissue water and blood flow as measured by magnetic resonance imaging and comparative methods /." Stockholm, 2001. http://diss.kib.ki.se/2001/91-628-4789-9/.
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D\'Ippolito, Silvia Fernandes Morgado. "Avaliação do músculo pterigóideo lateral por meio de ressonância magnética." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/23/23139/tde-19122009-120354/.
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O Músculo Pterigóideo Lateral (MPL) desempenha um papel importante nas Desordens Temporomandibulares (DTM), devido à íntima relação deste músculo com a Articulação Temporomandibular (ATM). No entanto, evidências de alterações patológicas dos músculos mastigatórios ainda parecem faltar nas pesquisas da DTM. Este estudo investigou o MPL por meio de Ressonância Magnética (RM) de 50 indivíduos com e sem DTM. Neste trabalho, das 100 ATM analisadas, 35 pacientes com DTM (70 ATM), prevalecendo o gênero feminino e 15 indivíduos sem sinais e sintomas clínicos de DTM (30 ATM) foram incluídos. O MPL foi observado e analisado em diferentes projeções. As imagens sagitais oblíquas e axiais da ATM foram capazes de mostrar os MPL claramente. Hipertrofia, atrofia e contratura do MPL foram as anomalias encontradas. Sinais de DTM, como hipermobilidade, hipomobilidade e deslocamento do disco articular puderam ser observados nas imagens de ATM. Com relação aos sintomas clínicos como dor, sons articulares, cefaléia e limitação nos movimentos mandibulares, foi possível observar que todos os pacientes com DTM apresentavam pelo menos um destes sintomas, sendo as queixas mais presentes dor e estalo; e os pacientes sem DTM também puderam mostrar alterações nas imagens de RM da ATM, como atrofia e contratura muscular, as mais observadas. O reconhecimento das alterações no MPL, podem levar a um diagnóstico mais específico e aumentar o entendimento dos sintomas clínicos e da fisiopatologia da DTM. Estudos futuros são necessários para se continuar avaliando o MPL por meio de RM.The Lateral Pterygoid Muscle (LPM) plays an important role in Temporomandibular Disorders (TMD), due to the close relation of this muscle with the Temporomandibular Joint (TMJ). However, evidence of pathological changes of the masticatory muscles still seems to be lacking in the TMD research. This study investigated the LPM by Magnetic Resonance Imaging (MRI) of 50 subjects with and without TMD. In this work, 100 Temporomandibular joints were analyzed, 35 subjects with TMD (70 TMJs), with the prevalence of female and 15 subjects without clinical signs and symptoms (30 TMJs) were included. The LPM was visible in different projections and analyzed. The oblique sagital and axial images of the TMJ were able to show the LPM clearly. Hipertrophy, atrophy and contracture of the LPM were the abnormalities found. TMD signs, such as hipermobility, hipomobility, disc displacement could be seem in the TMJ images. Related to clinical symptoms like pain, articular sounds, headache, and limitation of mandibular movements, it was possible to observed that all patients with TMD had at least one of these symptoms, pain and click being the most frequent complaint. Patients without TMD could also show alterations in the TMJ MRI, such as atrophy and contracture as the most common. The recognition of LPM alterations may lead to a more specific diagnosis and improvement of understanding of the clinical symptoms and pathophysiology of TMD. Further studies should be necessary to continue evaluating the LPM by MRI.
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Tonson, Anne. "Exploration non invasive des effets de la croissance et de la maturation sur le muscle squelettique : étude métabolique et fonctionnelle chez l'homme." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22004.
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Au cours de la croissance et de la maturation, le muscle squelettique subit de nombreux changements. Principalement on constate une augmentation considérable de la masse musculaire concomitante à l’augmentation de la capacité de force et plusieurs résultats suggèrent que la maturation affecte la fonction musculaire à la fois au niveau de la commande motrice et du métabolisme énergétique. Pour des raisons éthiques évidentes, la fonction musculaire n’a été que peu étudiée chez l’enfant. Malgré leur caractère strictement non-invasif les techniques de résonance magnétique n’ont été que peu utilisées pour caractériser cette fonction chez l’enfant et les résultats controversés ne permettent pas de dégager un consensus. Dans ce travail la fonction musculaire de l’enfant sain a été étudiée in vivo par Imagerie et Spectroscopie de Résonance Magnétique. Par IRM, nous nous avons mis en évidence que la capacité de force volontaire maximale d’un muscle reste proportionnelle à sa taille de l’enfance à l’âge adulte. Par ailleurs nos résultats obtenus par SRM du P31 ont clairement montré que la capacité oxydative et la production d’ATP mitochondriale était augmentée avant la puberté, illustrant que les enfants sollicitaient plus leur métabolisme aérobie que les adultes pour répondre à la demande énergétique pour une intensité donnée. De plus, nos résultats ont montré que la filière énergétique de la glycolyse anaérobie était pleinement mature dès l’enfance. Enfin, face à la difficulté pour mettre en place des études longitudinales chez l’homme nous avons développé un protocole expérimental permettant le suivi longitudinal de la fonction musculaire au cours du développement chez le ratGrowth and maturation are accompanied by important changes in skeletal muscle function (e.g. muscle mass and strength dramatically increase). Moreover, some evidences strongly suggest that maturation significantly affects skeletal muscle function both at the neural drive and energetics levels. For ethical reasons, few studies have been performed in children. Despite their non traumatic aspect the MR techniques, it has been barely used in this context. In this work, the skeletal muscle function of healthy children has been characterized in vivo using MRI and 31P-MRS. Our results refuted the hypothesis of a motor drive immaturity in children. We did not report any change in the relationship between muscle volume measured by MRI and maximum isometric strength or in specific strength from childhood to adulthood. The ability of a given muscle volume to produce force seems not to change during growth. Then, we investigated whether development affects muscle energetics using 31P-MRS comparing prepubescent boys and men. Our results showed that, for a similar total energy cost, the aerobic contribution to ATP production was significantly higher in boys and compensated for by a reduced PCr breakdown while glycolysis was similar whatever the age. In addition, the recovery rate of PCr after the standardized exercise was faster in boys illustrating a higher maximal oxidative capacity before puberty. Finally, our understanding of skeletal muscle function in children is still limited by the difficulty to perform longitudinal studies. In that respect, we have initiated an original protocol allowing the longitudinal investigation of the gastrocnemius muscle throughout development in rat
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Ferguson, Connor R. "QUANTIFICATION OF PAPILLARY MUSCLE MOTION AND MITRAL REGURGITATION AFTER MYOCARDIAL INFARCTION." UKnowledge, 2019. https://uknowledge.uky.edu/me_etds/136.
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Change in papillary muscle motion as a result of left ventricular (LV) remodeling after posterolateral myocardial infarction is thought to contribute to ischemic mitral regurgitation. A finite element (FE) model of the LV was created from magnetic resonance images acquired immediately before myocardial infarction and 8 weeks later in a cohort of 12 sheep. Severity of mitral regurgitation was rated by two-dimensional echocardiography and regurgitant volume was estimated using MRI. Of the cohort, 6 animals (DC) received hydrogel injection therapy shown to limit ventricular remodeling after myocardial infarction while the control group (MI) received a similar pattern of saline injections. LV pressure was determined by direct invasive measurement and volume was estimated from MRI. FE models of the LV for each animal included both healthy and infarct tissue regions as well as a simulated hydrogel injection pattern for the DC group. Constitutive model material parameters for each region in the FE model were assigned based on results from previous research. Invasive LV pressure measurements at end diastole and end systole were used as boundary conditions to drive model simulations for each animal. Passive stiffness (C) and active material parameter (Tmax) were adjusted to match MRI estimations of LV volume at end systole and end diastole. Nodal positions of the chordae tendineae (CT) were determined by measurements obtained from the excised heart of each animal at the terminal timepoint. Changes in CT nodal displacements between end systole and end diastole at 0 and 8-week timepoints were used to investigate the potential contribution of changes in papillary muscle motion to the progression of ischemic mitral regurgitation after myocardial infarction. Nodal displacements were broken down into radial, circumferential, and longitudinal components relative to the anatomy of the individual animal model. Model results highlighted an outward radial movement in the infarct region after 8 weeks in untreated animals, while radial direction of motion observed in the treated animal group was preserved relative to baseline. Circumferential displacement decreased in the remote region in the untreated animal group after 8 weeks but was preserved relative to baseline in the treated animal group. MRI estimates of regurgitant volume increased significantly in the untreated animal group after 8 weeks but did not increase in the treated group. The results of this analysis suggest that hydrogel injection treatment may serve to limit changes in papillary muscle motion and severity of mitral regurgitation after posterolateral myocardial infarction.
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Gast, Lena [Verfasser], Bernhard [Akademischer Betreuer] Hensel, Armin [Akademischer Betreuer] Nagel, and Bernhard [Gutachter] Hensel. "Magnetic resonance imaging of physiological sodium (23Na) and potassium (39K) ions in human skeletal muscle tissue at 3T and 7T / Lena Gast ; Gutachter: Bernhard Hensel ; Bernhard Hensel, Armin Nagel." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2020. http://d-nb.info/1219303542/34.
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Paula, Thalita Sousa de. "Resposta pós-exercício vista na ressonância nuclear magnética do músculo quadriceps em mulheres pós-menopáusicas com ou sem osteoporose." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/5/5160/tde-12062018-121009/.
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A menopausa é o final da vida reprodutiva da mulher e pode ter como consequência a perda da massa óssea e desenvolvimento da osteoporose. A sarcopenia decorrente do processo de envelhecimento acarreta na diminuição de massa e força muscular, déficit de desempenho e maior risco de quedas e fraturas. A Ressonância Nuclear Magnética (RNM) é uma ferramenta não invasiva e eficaz para a avaliação quantitativa e da dinâmica metabólica do músculo esquelético. Por meio do mapa T2 é possível captar as alterações musculares agudas causadas pela atividade física. A intensificação do sinal T2 é causada pelo movimento osmótico da água intramuscular, aumento da acidose e do volume do espaço intracelular. O objetivo desta pesquisa foi avaliar a influência da densidade mineral óssea no metabolismo muscular de mulheres pós-menopáusicas. Foram avaliadas 16 pacientes do sexo feminino, no período pós-menopausa há mais de 12 meses, com média de idade de 63 anos, divididas em Grupo-Osteoporose (GO=9) e Grupo Controle (CG=7). Todas foram submetidas ao exame de Ressonância Nuclear Magnética da região da coxa (RNM1) e em seguida fizeram uma dinamometria isocinética na velocidade de 180 graus/segundo (duas séries de 10 contrações voluntárias máximas) e exercícios específicos para ativação do músculo quadríceps (agachamento e \"step\"), e após os exercícios, fizeram a RNM2. Os resultados mostraram aumento do mapa T2, caracterizado pelo maior tempo de relaxamento nos dois grupos avaliados, sem diferença entre eles. Não se observou correlação significativa dos resultados da RNM2 com os parâmetros de força (pico de torque corrigido pela massa corporal) e potência (trabalho total das 10 repetições da segunda série) e com a dosagem de vitamina D. Também não houve correlação entre a dinamometria isocinética e dosagem de vitamina D. A osteoporose não afeta a resposta muscular do quadríceps ao exercício, avaliada pelo mapa T2 da ressonância nuclear magnética. A metodologia é robusta e eficiente, mostrando que a RM é um método sensível para medir mudanças metabólicas no músculo após o exercícioMenopause is the end of woman\'s reproductive life and consequences as loss of bone mass and osteoporosis may emerge. The ageing\'s sarcopenia entails the reduction of muscle mass and strength, deficit of physical performance and increases the risk of falls and fractures, which is also present in postmenopausal women. Magnetic resonance imaging (MRI) is a noninvasive and effective tool for quantitative assessment and metabolic dynamics of skeletal muscle. Through the T2 map is possible to capture acute muscle disorders caused by physical activity. Intensification of T2 sign is caused by osmotic movement of intramuscular water, increase of acidosis and intracellular space volume. The aim of this study was to evaluate bone mineral density in muscle metabolism in postmenopausal women. We evaluated 8 female patients in postmenopausal for more than 12 months, with a mean age of 63 years, divided into osteoporosis-group (GO=9) and control group (CG=7). They were submitted to MRI examination of thigh at rest (RM1), and then the isokinetic dynamometer at the speed of 180 degrees/second, 2 sets of 10 maximal voluntary contractions and specific exercises to activate the quadriceps muscle (squats and step) and then the RM2 to capture the muscle metabolic changes. For perception of fatigue level, samples of lactate were taken at rest (Lac1), after 1 minute (lac2) and 3 minutes (Lac3) from the end of the exercises. In both groups, it was observed variation of lac2 Lac3, confirming that fatigue levels and changes in RM2 compared to RM1 in the uptake of water were achieved due to intramuscular specific physical changes in post-exercise muscle metabolism. The results showed increased T2 map, characterized by the highest relaxation time in both groups and there are no difference between them. There was no significant correlation of the results of the RNM2 with the parameters of force (peak torque corrected by body mass) and potency (total work) and with the dosage of vitamin D. There was also no correlation between the isokinetic dinamometria and dosage of vitamin D. Osteoporosis does not affect the muscle response of the quadriceps to exercise, assessed by the T2 map of magnetic resonance imaging. The methodology proved to be robust and efficient, showing that MRI is a sensitive method to measure metabolic changes in muscle after exercise
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Caldas, de Almeida Araujo Ericky. "Adaptation of Proof of Concepts Into Quantitative NMR Methods : Clinical Application for the Characterization of Alterations Observed in the Skeletal Muscle Tissue in Neuromuscular Disorders." Phd thesis, Université Paris Sud - Paris XI, 2014. http://tel.archives-ouvertes.fr/tel-01067940.
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Current quantitative nuclear magnetic resonance (NMR) technics offer biomarkers that allow performing non-invasive longitudinal studies for the follow up of therapeutic trials in neuromuscular disorders (NMD). In contrast to fat degeneration, the mechanisms of inflammation/oedema/necrosis and fibrosis are characteristic signs of disease activity, which makes their quantification a promising source of crucial biomarkers for longitudinal studies. This thesis work consisted on the implementation of more precise quantitative NMR methods adapted to the clinical study of skeletal muscle (SKM) for : (i) detection and quantification of sites of disease activity by T2-mapping of muscle water ; (ii) investigation of the different pathophysiological mechanisms underlying T2 alterations ; and (iii) Detection and quantification of muscle fibrosis. We implemented two methods for T2 mapping of muscle water. The first one is based on a multi-spin-echo sequence du type CPMG. In this method the 1H-NMR signals from water and lipids are acquired simultaneously. The acquired data are fitted to a tri-exponential model, in which water and fat signals are separated by exploring the T2 difference between water and fat. This method allows extraction of muscle water T2-value in the presence of fat infiltration. The second method is based on a " partially spoiled steady state free precession " (pSSFP) sequence. In contrast to the first method, which demands a sophisticated post-treatment of images acquired at 17 different echo-times, with the pSSFP a T2-mapping is extracted from two 3D data sets. 3D acquisition is compatible with spectrally selective water excitation, which eliminates signal contribution from lipids. Both methods were validated experimentally on patients and healthy subjects. The results demonstrated their capacity to detect and quantify disease activity sites. This 2 works have been published in two international journals : Azzabou, de Sousa, Araujo, & Carlier, 2014. Journal of Magnetic Resonance Imaging. DOI 10.1002/jmri.24613 (in press); et de Sousa, Vignaud, Araujo, & Carlier . 2012. Magnetic Resonance in Medicine. 67:1379-1390. Although it was shown to reveal disease activity, mono-exponential T2 of muscle water is non-specific to what concerns the mechanisms underlying its alterations. It has been long known that T2 relaxation in SKM tissue is multi-exponential. This is currently accepted to reveal anatomical compartmentation of myowater. We implemented a method for localized spectroscopic CPMG acquisition. CPMG data respect echo-time sampling and signal to noise ration limits for allowing robust multiexponential analysis. This work allowed us to establish a compartmentation model that perfectly explains the multi-exponential T2 relaxation observed in SKM tissue. This work was published in the " Biophysical Journal " (Araujo, Fromes & Carlier 2014. New Insights on skeletal muscle tissue compartments revealed by T2 NMR relaxometry. (In press)). Pilot studies performed in patients show promising results and suggest potential application of the method in clinical studies. Fibrosis starts with an excessive accumulation of intramuscular connective tissue (IMCT). We have explored the " Ultrashort time to echo " (UTE) method with the aim to detect and characterize the signal from IMCT. In a first study we characterized in vivo a short T2 component (~500 µs) in SKM, and we collected evidences suggesting that this component might reflect IMCT. Then we implemented a methodology that allowed imaging this short component in SKM tissue for the first time.
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Lee, Kuan Jin. "Fast magnetic resonance imaging." Thesis, University of Sheffield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397487.
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O'Neil, Shannon M. "Magnetic resonance imaging centers /." Online version of thesis, 1994. http://hdl.handle.net/1850/11916.
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Dakpé, Stéphanie. "Etude biomécanique de la mimique faciale." Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2203/document.
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Ce travail de thèse, inclus dans un projet structurant plus vaste, projet SIMOVI (SImulation des MOuvements du VIsage), s’attache à étudier spécifiquement la mimique faciale en corrélant les déplacements visibles du revêtement cutané et les mouvements musculaires internes à travers le développement de plusieurs méthodologies. L’ensemble de la mimique faciale ne pouvant être étudié, étant donné la multitude d’expressions, les mouvements pertinents à étudier dans nos travaux ont été identifiés. Ces mouvements ont été caractérisés chez 23 sujets jeunes dans une analyse descriptive qualitative et clinique, basée sur une méthodologie s’appuyant sur l’analyse d’enregistrements vidéoscopiques, et le développement d’un codage issu du FACS (Facial Action Coding System). Une cohorte de référence a ainsi été constituée. Après avoir validé notre méthodologie pour la caractérisation externe de la mimique, l’analyse des muscles peauciers par l’IRM a été réalisée sur 10 hémifaces parmi les sujets sains issus de la cohorte. Cette caractérisation a fait appel, à partir d’une anatomie in vivo, à une modélisation de certains muscles peauciers (zygomaticus major en particulier) afin d’extraire des paramètres morphologiques, de réaliser une analyse plus fine de la morphologie musculaire en 3 dimensions, et d’apporter une meilleure compréhension du comportement cinématique du muscle dans différentes positions. Par son intégration dans un questionnement plus vaste :- comment caractériser objectivement la mimique faciale ? - quels sont les indicateurs qualitatifs et quantitatifs de la mimique que nous pouvons recueillir, et comment réaliser ce recueil ? - comment utiliser les développements technologiques dans les applications cliniques ? Ce travail constitue une étape préliminaire à d’autres travaux. Il pourra fournir des données de référence à des fins de modélisation, de simulation de la mimique faciale, ou de développements d’outil de mesures pour le suivi et l’évaluation des déficits de la mimique facialeThe aim of this research is to study facials mimics movements and to correlate externat soft tissue (i.e., cutaneous) movement during facial mimics with internal (i.e., facial mimic muscle) movement. The entire facial mimicry couldn't be studied, that's why relevant movements had been selected. Those movements were characterised by a clinically qualitative analysis in 23 young healthy volunteers. The analysis was performed with video recordings including scaling derived from the FACS (Facial Action Coding System). After the validation of external characterisation by this method, internal characterisation of the mimic facial muscle was carried out in 10 volunteers. A modelization of selected facial mimic muscle as Zygomaticus Major was achieved. With this work, morphological parameters could be extracted, 3D morphometric data were analysed to provide a better understanding of cinematic behaviour of muscle in different positions.This research is included in the Simovi Project, which aims to determine to what extent a facial mimic can be evaluated objectively, to select the qualitative and quantitative indicators for evaluation of mimic facial disorders, and to transfer our technological developments in clinical field. This research is a first step and provides data for simulation or developments of measurement tools in evaluation and follow-up of mimic facial disorders
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Lu, Wenmiao. "Off-resonance correction in magnetic resonance imaging /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Petropoulos, Labros Spiridon. "Magnetic field issues in magnetic resonance imaging." Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1060710667.
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Campbell, Jennifer 1975. "Magnetic resonance diffusion tensor imaging." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30809.
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Magnetic resonance imaging (MRI) can be used to image diffusion in liquids, such as water in brain structures. Molecular diffusion can be isotropic or anisotropic, depending on the fluid's environment, and can therefore be characterized by a scalar, D, or by a tensor, D, in the respective cases. For anisotropic environments, the eigenvector of D corresponding to the largest eigenvalue indicates the preferred direction of diffusion.This thesis describes the design and implementation of diffusion tensor imaging on a clinical MRI system. An acquisition sequence was designed and post-processing software developed to create diffusion trace images, scalar anisotropy maps, and anisotropy vector maps. A number of practical imaging problems were addressed and solved, including optimization of sequence parameters, accounting for flow effects, and dealing with eddy currents, patient motion, and ghosting. Experimental validation of the sequence was performed by calculating the trace of the diffusion tensor measured in various isotropic liquids. The results agreed very well with the quantitative values found in the literature, and the scalar anisotropy index was also found to be correct in isotropic phantoms. Anisotropy maps, showing the preferred direction of diffusion, were generated in human brain in vivo. These showed the expected white matter tracts in the corpus callosum.
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Lindsay, Alistair. "Magnetic resonance imaging of atherosclerosis." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526491.
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Glover, Paul Martin. "High field magnetic resonance imaging." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335575.
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Yoo, Seung-Schik 1970. "Adaptive functional magnetic resonance imaging." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/70893.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2000.Some research performed with the Harvard-M.I.T. Division of Health Sciences and Technology.
Includes bibliographical references (leaves 132-140).
Functional MRI (fMRI) detects the signal associated with neuronal activation, and has been widely used to map brain functions. Locations of neuronal activation are localized and distributed throughout the brain, however, conventional encoding methods based on k-space acquisition have limited spatial selectivity. To improve it, we propose an adaptive fMRI method using non-Fourier, spatially selective RF encoding. This method follows a strategy of zooming into the locations of activation by progressively eliminating the regions that do not show any apparent activation. In this thesis, the conceptual design and implementation of adaptive fMRI are pursued under the hypothesis that the method may provide a more efficient means to localize functional activities with increased spatial or temporal resolution. The difference between functional detection and mapping is defined, and the multi- resolution approach for functional detection is examined using theoretical models simulating variations in both in-plane and through-plane resolution. We justify the multi-resolution approach experimentally using BOLD CNR as a quantitative measure and compare results to those obtained using theoretical models. We conclude that there is an optimal spatial resolution to obtain maximum detection; when the resolution matches the size of the functional activation. We demonstrated on a conventional 1.5-Tesla system that RF encoding provides a simple means for monitoring irregularly distributed slices throughout the brain without encoding the whole volume. We also show the potential for increased signal-to-noise ratio with Hadamard encoding as well as reduction of the in-flow effect with unique design of excitation pulses.
(cont.) RF encoding was further applied in the implementation of real-time adaptive fMRI method, where we can zoom into the user-defined regions interactively. In order to do so, real-time pulse prescription and data processing capabilities were combined with RF encoding. Our specific implementation consisted of five scan stages tailored to identify the volume of interest, and to increase temporal resolution (from 7.2 to 3.2 seconds) and spatial resolution (from 10 mm to 2.5-mm slice thickness). We successfully demonstrated the principle of the multi- resolution adaptive fMRI method in volunteers performing simple sensorimotor paradigms for simultaneous activation of primary motor as well as cerebellar areas.
by Seung-Schik Yoo.
Ph.D.
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Eichner, Cornelius. "Slice-Accelerated Magnetic Resonance Imaging." Doctoral thesis, Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-184944.
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This dissertation describes the development and implementation of advanced slice-accelerated (SMS) MRI methods for imaging blood perfusion and water diffusion in the human brain. Since its introduction in 1977, Echo-Planar Imaging (EPI) paved the way toward a detailed assessment of the structural and functional properties of the human brain. Currently, EPI is one of the most important MRI techniques for neuroscientific studies and clinical applications. Despite its high prevalence in modern medical imaging, EPI still suffers from sub-optimal time efficiency - especially when high isotropic resolutions are required to adequately resolve sophisticated structures as the human brain. The utilization of novel slice-acceleration methods can help to overcome issues related to low temporal efficiency of EPI acquisitions.
The aim of the four studies outlining this thesis is to overcome current limitations of EPI by developing methods for slice-accelerated MRI. The first experimental work of this thesis describes the development of a slice-accelerated MRI sequence for dynamic susceptibility contrast imaging. This method for assessing blood perfusion is commonly employed for brain tumor classifications in clinical practice. Following up, the second project of this thesis aims to extend SMS imaging to diffusion MRI at 7 Tesla. Here, a specialized acquisition method was developed employing various methods to overcome problems related to increased energy deposition and strong image distortion. The increased energy depositions for slice-accelerated diffusion MRI are due to specific radiofrequency (RF) excitation pulses. High energy depositions can limit the acquisition speed of SMS imaging, if high slice-acceleration factors are employed. Therefore, the third project of this thesis aimed at developing a specialized RF pulse to reduce the amount of energy deposition. The increased temporal efficiency of SMS imaging can be employed to acquire higher amounts of imaging data for signal averaging and more stable model fits. This is especially true for diffusion MRI measurements, which suffer from intrinsically low signal-to-noise ratios. However, the typically acquired magnitude MRI data introduce a noise bias in diffusion images with low signal-to-noise ratio. Therefore, the last project of this thesis aimed to resolve the pressing issue of noise bias in diffusion MRI. This was achieved by transforming the diffusion magnitude data into a real-valued data representation without noise bias. In combination, the developed methods enable rapid MRI measurements with high temporal efficiency. The diminished noise bias widens the scope of applications of slice- accelerated MRI with high temporal efficiency by enabling true signal averaging and unbiased model fits. Slice-accelerated imaging for the assessment of water diffusion and blood perfusion represents a major step in the field of neuroimaging. It demonstrates that cur- rent limitations regarding temporal efficiency of EPI can be overcome by utilizing modern data acquisition and reconstruction strategies.
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Harvey, Ian. "Magnetic resonance imaging in schizophrenia." Thesis, University of Edinburgh, 1991. http://hdl.handle.net/1842/19829.
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Thompson, William Kevin. "T2 Mapping of Muscle Activation During Single-Leg Vertical Jumping Exercise." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1194982561.
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Sharkey-Toppen, Travis P. "Imaging Iron and Atherosclerosis by Magnetic Resonance Imaging." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429796182.
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Yoshimaru, Eriko Suzanne. "Magnetic Resonance Imaging Techniques for Rodent Pulmonary Imaging." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/293388.
Full textAbstract:
Magnetic Resonance Imaging (MRI) is a safe and widely used diagnostic imaging method that allows in vivo observation of anatomy and characterization of tissues. MRI provides a method to monitor patients without invasive measures, making it suitable for both diagnostics and longitudinal monitoring of various pathologies. A notable example of this is the work carried out by the Alzheimer's Disease Neuroimaging Initiative (ADNI), which utilizes imaging, including multiple MRI techniques, to monitor disease progression in AD patients and evaluates treatment responses and prevention strategies. Similarly, MRI has been extensively used in evaluating diseases in a variety of animal models. In order to detect subtle anatomical changes over time, small differences in MR images must be accurately extracted. Furthermore, to ensure that the extracted differences are due to anatomical changes rather than equipment variance, it becomes essential to monitor and to assess the MRI system stability. In the first chapter of the dissertation, a method for monitoring pre-clinical MRI system performance is discussed. The technique developed during the study provides a fast and simple method to monitor pre-clinical MRI systems but also has applications for all areas of MRI. The second chapter describes the development of a 3D UTE MRI method for pulmonary imaging in freely breathing mice. The development of the 3D UTE sequence for pulmonary MRI has demonstrated its ability to collect images without noticeable motion artifacts and with appreciable signal from the lung parenchyma. Furthermore, images at two distinct respiratory phases were reconstructed from a single data set, providing functional information of the rodents' lungs. Finally, in the third chapter, 3D ¹⁹F UTE MRI is evaluated for imaging in vivo distributions of perfluorocarbon (PFC) nanoemulsions for measuring pulmonary inflammation. Building upon the development of pulmonary imaging, fluorinated contrast agents made from PFCs were used to target immune cells in response to pulmonary pathology. Both 3D ¹H and ¹⁹F UTE MRI were used to acquire pulmonary images of mouse models documented to have pulmonary pathology. Even though the mice had confirmed elevation in alveolar macrophage counts, no visible ¹⁹F signal accumulation within the pulmonary tissue was observed with MRI.
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MA, DAN. "Magnetic Resonance Fingerprinting." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1426170542.
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Tavoian, Dallin. "Tools and Technologies for Assessing, and Exercise Strategies for Promoting, Neuromuscular Function and Mobility in Aging." Ohio University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1615816378173099.
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Lei, Hao. "Magnetic resonance perfusion imaging and double quantum coherence transfer magnetic resonance spectroscopy." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0021/NQ45007.pdf.
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Tymofiyeva, Olga. "Magnetic resonance imaging in dental medicine." Göttingen Sierke, 2010. http://d-nb.info/1002094976/04.
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McDougall, Mary Preston. "Single echo acquisition magnetic resonance imaging." Texas A&M University, 2004. http://hdl.handle.net/1969.1/3324.
Full textAbstract:
The dramatic improvement in magnetic resonance imaging (MRI) scan time over the past fifteen years through gradient-based methods that sample k-space more efficiently and quickly cannot be sustained, as thresholds regarding hardware and safety limitations are already being approached. Parallel imaging methods (using multiple receiver coils to partially encode k-space) have offered some relief in the efforts and are rapidly becoming the focus of current endeavors to decrease scan time. Ideally, for some applications, phase encoding would be eliminated completely, replaced with array coil encoding instead, and the entire image formed in a single echo.
The primary objective of this work was to explore that acceleration limit  to implement and investigate the methodology of single echo acquisition magnetic resonance imaging (SEA MRI). The initial evaluation of promising array coil designs is described, based on parameters determined by the ability to enable the imaging method. The analyses of field patterns, decoupling, and signal-to-noise ratio (SNR) that led to the final 64-channel array coil design are presented, and the fabrication and testing of coils designed for 4.7T and 1.5T are described. A detailed description of the obtainment of the first SEA images  64xNreadout images, acquired in a single echo  is provided with an evaluation of those images and highly accelerated images (through parallel imaging techniques) based on SNR and artifact power. Finally, the development of methodologies for various MR applications is described: applications that would particularly benefit from the speed of the imaging method, or those to which the method or the tool (array coil) lends itself. These applications include, but are not limited to, 3D imaging (phase encode in the slice select direction), resolution-enhanced imaging, large-scale (field-of-view) microscopy, and conformal surface imaging. Finally, using the primary enablement of the method  the ability to obtain complete MR images at speeds limited only by the time it takes to acquire a single echo  is presented with a discussion of extremely high frame rate imaging.
The contribution to the field of medical imaging is the first implementation, characterization, and demonstration of applications for the acquisition of MR images in a single echo.
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Brown, David Gerald. "Instrumentation for parallel magnetic resonance imaging." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4784.
Full textAbstract:
Parallel magnetic resonance (MR) imaging may be used to increase either the
throughput or the speed of the MR imaging experiment. As such, parallel imaging may
be accomplished either through a "parallelization" of the MR experiment, or by the use
of arrays of sensors. In parallelization, multiple MR scanners (or multiple sensors) are
used to collect images from different samples simultaneously. This allows for an
increase in the throughput, not the inherent speed, of the MR experiment. Parallel
imaging with arrays of sensor coils, on the other hand, makes use of the spatial
localization properties of the sensors in an imaging array to allow a reduction in the
number of phase encodes required in acquiring an image. This reduced phase-encoding
requirement permits an increase in the overall imaging speed by a factor up to the
number of sensors in the imaging array. The focus of this dissertation has been the
development of cost-effective instrumentation that would enable advances in the state of
the art of parallel MR imaging.
First, a low-cost desktop MR scanner was developed (< $13,000) for imaging small
samples (2.54 cm fields-of view) at low magnetic field strengths (< 0.25 T). The
performance of the prototype was verified through bench-top measurements and
phantom imaging. The prototype transceiver has demonstrated an SNR (signal-to-noise ratio) comparable to that of a commercial MR system. This scanner could make
parallelization of the MR experiment a practical reality, at least in the areas of small
animal research and education.
A 64-channel receiver for parallel MR imaging with arrays of sensors was also
developed. The receiver prototype was characterized through both bench-top tests and
phantom imaging. The parallel receiver is capable of simultaneous reception of up to
sixty-four, 1 MHz bandwidth MR signals, at imaging frequencies from 63 to 200 MHz,
with an SNR performance (on each channel) comparable to that of a single-channel
commercial MR receiver. The prototype should enable investigation into the speed
increases obtainable from imaging with large arrays of sensors and has already been
used to develop a new parallel imaging technique known as single echo acquisition
(SEA) imaging.
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Hill, Richard J. "Developments in quantitative magnetic resonance imaging." Thesis, University of Surrey, 1999. http://epubs.surrey.ac.uk/843527/.
Full textAbstract:
Two magnetic resonance imaging studies based on relaxometry are presented. Firstly, various methods of measuring T1, T2, and flip angle are reviewed, along with various applications of relaxometry. After a study of the relevant background and theory, a method of measuring T1, T2, and the flip angle simultaneously using echo planar imaging is described, followed by a study of diffusion in a biological system employing T2 measurements. A series of echo planar images acquired with a repetition time that is short compared with the relaxation times T1 and T2 shows fluctuations in image intensity, which are dependent on these relaxation times and the flip angle. These fluctuations are best modelled using the Kaiser theory of isochromats. The Levenberg-Marquardt non-linear least squares algorithm can then be used to estimate the parameters from the data. This has been shown to work consistently in zero and one dimensions, but inconsistently in two dimensions when high gradient amplitudes affect coherence. Bacterial polysaccharides are known to exhibit a property known as anion exclusion, where the diffusion of cations is permitted, but the diffusion of anions is prevented. According to the theory of permselectivity, negatively-charged functional groups on the surfaces of pores not only block anions, but assist the diffusion of cations. The relationship between T2 and the concentration of paramagnetic species is used to follow the diffusion of Mn2+ ions through several polysaccharides. It is shown that the diffusion coefficients of Mn2+ ions are higher in neutral than in positively-charged polysaccharides, and greater still in negatively charged polysaccharides.
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Kristoffersen, Wiberg Maria. "Magnetic resonance imaging in breast diagnosis /." Stockholm : Karolinska Univ. Press, 2002. http://diss.kib.ki.se/2002/91-7349-343-0.
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Blomqvist, Lennart. "Magnetic resonance imaging of rectal tumours /." Stockholm, 1997. http://diss.kib.ki.se/1997/91-628-2797-9.
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Munasinghe, B. D. Jeeva P. "Nuclear magnetic resonance imaging of mice." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337912.
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