Literatura científica selecionada sobre o tema "Imagerie par résonance magnétique de réhaussement tardif"
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Teses / dissertações sobre o assunto "Imagerie par résonance magnétique de réhaussement tardif"
Mewton, Nathan. "Imagerie cardiaque par résonance magnétique à la phase aigüe de l'infarctus du myocarde : de la physiopathologie à l'évaluation des nouvelles thérapeutiques de reperfusion". Thesis, Lyon 1, 2009. http://www.theses.fr/2009LYO10293.
Texto completo da fonteWe assessed the presence and extent of microvascular obstruction (MVO) and its relationship with infarct size and left ventricular (LV) functional parameters after acute non-ST elevated myocardial infarction (NSTEMI). 25 patients with first acute NSTEMI underwent a complete cardio magnetic resonance (CMR) study 72 hours after admission. MO was detected in 32% of patients and was significantly associated with a larger infarct size. There were no significant difference between both groups for the LV functional parameters but patients with MO showed a higher troponin-I and CK release. We studied the relation between Myocardial Blush Grade (MBG) and gadolinium-enhanced CMR for the assessment of MVO in 39 patients with acute ST elevated myocardial infarction (STEMI) treated by primary PCI. No statistical relation was found between MBG and MVO extent at CMR (p=0.63). MBG underestimates MVO after an optimal revascularization in AMI compared to CMR.We compared the performance and post-processing time of a global visual scoring method to standard quantitative planimetry and we compared both methods to the peak values of myocardial biomarkers. 103 patients admitted with reperfused AMI to our intensive care unit had a complete CMR study 4±2 days after admission. There was an excellent correlation between quantitative planimetry and visual global scoring for the hyperenhancement extent’s measurement (r=0.94; y=1.093x+0.87; SEE=1.2; P<0.001) and there was also a good concordance between the two approaches with significantly shorter mean post-processing time for the visual scoring method. There was also significant levels of correlation between the enzymatic peak values and the visual global scoring method. The visual global scoring method allows a rapid and accurate assessment of the myocardial global delayed enhancement. This study examined the effect of a single dose of cyclosporine A used at the time of reperfusion, on LV remodeling and function by cardiac magnetic resonance (CMR) in the early days and 6 months after AMI.28 patients of the original cyclosporine A study had an acute (day 5) and a follow-up (6 months) CMR study. There was a persistent 23% reduction of the absolute infarct size at 6 months without any dementrial effect in the cyclosporine A group compared with the control group of patients. Cyclosporine A used at the moment of AMI reperfusion persistently reduces infarct size and does not have a detrimental effect on LV remodeling
Laredo, Mikaël. "Nouveaux développements techniques et applications cliniques de l'imagerie par résonance magnétique cardiaque et tomodensitométrie pour le diagnostic et la caractérisation de la cardiomyopathie arythmogène". Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS568.pdf.
Texto completo da fonteArrhythmogenic cardiomyopathies (ACM) constitute a spectrum of genetically-determined cardiac diseases of which the main consequence are ventricular arrhythmias potentially leading to sudden cardiac death. Arrhythmogenic cardiomyopathies have a diverse range of clinical-imaging phenotypes, and a continuously evolving landscape including concealed structural changes requiring multiparametric assessment. Cardiac magnetic resonance (CMR) is central in their evaluation, given the growing identification of biventricular and left-ventricular(LV)-predominant ACM variants. Multidetector computed tomography (MDCT), while not as established, offers potential utility as either an adjunct or alternative tool. In this thesis, we took advantage on our large ACM cohort to pursue three aims able to extend the boundaries of cardiac imaging for ACM diagnosis and functional characterization. First, we developed and evaluated a novel feature-tracking CMR parameter that integrates both longitudinal and radial right ventricular (RV) dynamics, which was effective in distinguishing ACM patients, particularly those lacking major structural criteria, from healthy subjects, implying that a two-dimensional representation of RV dynamics is crucial to capture the complex physiology of ACM. Second, we described the CMR features of Desmoplakin (DSP)-related ACM, a specific entity associated with particularly worse outcomes amidst the wide diversity of ACMs, and for the first time compared them to those found in ACM with LV involvement. We found that the presence of diffuse late gadolinium enhancement extending beyond the inferolateral LV combined with an end-systolic LV-to-RV volume ratio ≥0.8 may be considered as indicative of a high pre-genetical test results likelihood for DSP-ACM. Third, through a transversal multimodality study, we showed there was overall a low spatial concordance between the arrhythmogenic substrate and morpho-functional abnormalities or RV fat, at a segmental level. This finding paves the way for an integration of EP data into ACM diagnostic criteria and suggest that routine practice cardiac imaging cannot reliably exclude the presence of an EP substrate in a given RV location. Determinant improvements are currently being undertaken to increase the impact and generalizability of the three sets of results
Lecesne, Erwan. "Planification et assistance par fusion d'images multimodales pour l'optimisation de gestes de réparation tissulaire en insuffisance cardiaque". Electronic Thesis or Diss., Université de Rennes (2023-....), 2024. http://www.theses.fr/2024URENS001.
Texto completo da fonteThe research in this thesis is situated in the clinical context aimed at optimizing procedures during cardiac endoventricular interventions. This study primarily focuses on guidance for the diagnosis and treatment of endoventricular conditions using catheters. The specific intervention under consideration is the endoventricular biopsy used for diagnosing patients with cardiac sarcoidosis. Indeed, the catheter must be precisely guided to the fibrotic zone. However, the lack of precise visual information on the location of fibrosis during the intervention increases the risk of false negatives for the collected samples. Additionally, there is a risk of complications such as myocardial perforation, also known as cardiac tamponade. The objectives of this thesis are articulated in two distinct parts: The first part, preoperative, involves developing a 3D model of the heart, encompassing the left ventricle, right ventricle, and myocardium. This model is constructed from segmentations of MRI images, including cine sequences for the main structures and late gadolinium-enhanced (LGE) images to locate fibrotic zones. The segmentation methods developed rely on deep learning, and the fibrosis segmentation method is the subject of an ongoing publication. The second part, intraoperative, aims to assist the procedure by providing precise information about the anatomy and location of the fibrotic zone. This optimizes the positioning of the catheter on the periphery of this fibrotic zone, thereby contributing to improving the precision and efficiency of the intervention. Finally, the entire processing pipeline has been successfully tested on three patients, providing valuable feedback for clinicians. These advancements aim to reduce the risks associated with endoventricular biopsy and enhance the precision of cardiac sarcoidosis diagnosis, paving the way for significant progress in the management of this pathology
Schneider, Fabien. "Analyse de l'évolution des anomalies de diffusion et de perfusion en IRM au stade aigu et tardif de l'accident vasculaire cérébral". Lyon 1, 2005. http://www.theses.fr/2005LYO10007.
Texto completo da fonteBière, Loïc. "Analyse quantitative des paramètres issus de l'IRM cardiaque". Thesis, Angers, 2015. http://www.theses.fr/2015ANGE0072.
Texto completo da fonteThe various aspect of cardiac function may now be investigated non-invasively by cardiac imaging. Cardiac magnetic resonance (CMR) allows to study multiple parameters in one time, including function, perfusion, tissular characteristics and fibrosis. There is a need to propose adequate and objective criteria for CMR analysis, which may be warranted by a quantitative analysis. We prospectively followed 195 patients with a first ST elevation myocardial infarction and successful revascularisation. CMR were performed at baseline and 3 months. We analysed ventricular volumes, systolic wall stress, infarct size, microvascular obstruction, and pericardial effusion extent. A cohort of 42 patients with hypertrophic cardiomyopathy were also studied. We demonstrated the clinical interest for semi-automated analysis of late gadolinium enhancement imaging. The use of the FWHM algorithm appeared strongly related to left ventricular volumes at 3 months. Then we depicted the lack of relationships between electrocardiograms and fibrosis in patients with hypertrophic cardiomyopathy. The presence of q waves appeared to be related to cardiac phenotype, namely higher septal to posterior ratios. We showed the impairment of myocardial deformations in regard of myocardial fibrosis following a myocardial infarction. We found a much depressed deformation in case of microvascular obstruction and an interest for longitudinal global strain for the prediction of infarct size at 3 months. We also studied the determinants of post-infarction heart failure on one part, pericardial effusion on the other, by the use of a CMR multiparametric approach. Infarct size and systolic wall stress were the best markers of in-hospital and post-discharge heart failure, respectively. A pericardial effusion was found in 58.5% of the patients with a mean size of 31.6±24.0 ml. The determinants by multivariate analysis were infarct size, microvascular obstruction and systolic wall stress. Our results highlighted the interest for a quantitative and multiparametric approach of CMR. Further applications are expected in both descriptive and randomized studies
Gour, Natalina. "Réorganisation des systèmes anatomo-fonctionnels et de la topologie cérébrale entre les formes à début précoce et tardif de maladie d'Alzheimer. : Approche comportementale et en IRMf de repos". Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM5069.
Texto completo da fonteCognitive functions rely on the dynamic interplay of connected brain regions. Previous studies suggest that in Alzheimer disease (AD), early pathological changes target one or several specific anatomo-functional networks. Dysfunction of the default mode network is a consistent finding. However, its relationship with clinical symptoms and interconnected medial temporal regions remains to be clarified. Resting state functional MRI (fMRI) is an emerging method aimed at characterizing in vivo brain connectivity in the Human.Using a neural system approach, the aim of this thesis was to characterize neuronal functional reorganization in AD, its clinical correlates, and to determine the influence of age at onset. Neuropsychological data, structural and fMRI were obtained in subjects with early memory impairment and mild “amnestic” AD. This work provides new insights into : i) the functional role of the anterior temporal network in context-free declarative memory and its changes throughout the course of AD; ii) the common and specific features in targeted anatomo-functional networks between early and late onset AD ; iii) the reorganization of whole brain topological properties in the two forms of the disease
Betancur, Acevedo Julian Andrés. "Intégration d'images multimodales pour la caractérisation de cardiomyopathies hypertrophiques et d'asynchronismes cardiaques". Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S089/document.
Texto completo da fonteThis work concerns cardiac characterization, a major methodological and clinical issue, both to improve disease diagnostic and to optimize its treatment. Multisensor registration and fusion methods are proposed to bring into a common referential data from cardiac magnetic resonance (CMRI), dynamic cardiac X-ray computed tomography (CT), speckle tracking echocardiography (STE) and electro-anatomical mappings of the inner left ventricular chamber (EAM). These data is used to describe the heart by its anatomy, electrical and mechanical function, and the state of the myocardial tissue. The methods proposed to register the multimodal datasets rely on two main processes: temporal registration and spatial registration. The temporal dimensions of input data (images) are warped with an adaptive dynamic time warping (ADTW) method. This method allowed to handle the nonlinear temporal relationship between the different acquisitions. Concerning the spatial registration, iconic methods were developed, on the one hand, to correct for motion artifacts in cine acquisition, to register cine-CMRI and late gadolinium CMRI (LGE-CMRI), and to register cine-CMRI with dynamic CT. On the other hand, a contour-based method developed in a previous work was enhanced to account for multiview STE acquisitions. These methods were evaluated on real data in terms of the best metrics to use and of the accuracy of the iconic methods, and to assess the STE to cine-CMRI registration. The fusion of these multisensor data enabled to get insights about the diseased heart in the context of hypertrophic cardiomyopathy (HCM) and cardiac asynchronism. For HCM, we aimed to improve the understanding of STE by fusing fibrosis from LGE-CMRI with strain from multiview 2D STE. This analysis allowed to assess the significance of regional STE strain as a surrogate of the presence of regional myocardial fibrosis. Concerning cardiac asynchronism, we aimed to describe the intra-segment electro-mechanical coupling of the left ventricle using fused data from STE, EAM, CT and, if relevant, from LGE-CMRI. This feasibility study provided new elements to select the optimal sites for LV stimulation