Literatura académica sobre el tema "Imagerie par Résonance Magnétique multiparamétrique (IRM-mp)"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Índice
Consulte las listas temáticas de artículos, libros, tesis, actas de conferencias y otras fuentes académicas sobre el tema "Imagerie par Résonance Magnétique multiparamétrique (IRM-mp)".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Tesis sobre el tema "Imagerie par Résonance Magnétique multiparamétrique (IRM-mp)"
Arribarat, Germain. "Approche par IRM multiparamétrique pour le tronc cérébral". Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30334.
Texto completoConnecting the brain to the spinal cord, the brain stem Brainstem (BST) is an area of convergence of motor and sensory pathways. It has different nuclei, responsible for various functions such as motor skills, regulation of respiratory and cardiac rhythms, the origin of cranial nerves. Despite its importance in various neurodegenerative diseases, in vivo exploration of BST is still a challenge today. The resolution used, the low contrast and its location make it difficult to study in conventional magnetic resonance imaging (MRI). Based on various advanced MRI sequences, we carried out a study of the substantia nigra (SN) in a population of Parkinson's patients, an area located in the upper part of the BST. The results show that iron imaging combined with free water imaging suggests different underlying pathophysiological processes. Nevertheless, given the size of the structures studied, the need for precision remains necessary for more reliable identification. The originality of the proposal is to develop a method dedicated to BST, in order to best overcome the difficulties of its observation. By optimizing MRI acquisitions and several image processing, the results obtained show the possibility of easily identifying certain structures and stabilizing quantitative values. To conclude, still with the objective of improving MRI measurements, we were interested in MRI on human anatomical parts. Post-mortem MRI is used in this thesis for the detection and quantification of metals (iron) and correlation with histological techniques
Thebault, Caroline. "Liposomes théranostiques pour le ciblage magnétique et le relargage d'un antitumoral par ultrasons focalisés, suivis par IRM multiparamétrique". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066022.
Texto completoTheranostic systems with imaging and therapeutic properties are developed to monitor treatments in vivo. The strategy we propose here is to design thermosensitive drug-loaded magnetic liposomes to treat superficial colon tumors CT26 on mice. These nanocarriers can be accumulated in the tumor by using a magnetic field gradient and the drug release can be triggered by a local heating induced by HIFU (High Intensity Focused Ultrasounds). They have been developed by co-encapsulation of magnetic nanoparticles and the antitumoral drug CA4P (Combretastatin A-4 Phosphate) in thermosensitive liposomes. The high loading of maghemite (γ-Fe2O3) magnetic nanoparticles enables both magnetic targeting and in vivo monitoring by MRI of this Ultra-Magnetic Liposomes (UML). In vitro HIFU heating at the UML membrane transition temperature improved the drug release. In vivo UML biodistribution was evaluated with dynamic susceptibility contrast imaging adjusted in time acquisition in MRI and the magnetic targeting efficiency was shown with a new MRI imaging processing. Adjustments of in vivo HIFU sequences to locally heat the tumor at the UML transition temperature allowed the triggering of drug release. Treatment efficiency was monitored by multiparametric diffusion, T2* weighted, anatomical and perfusion MRI and histology
Duran, Audrey. "Intelligence artificielle pour la caractérisation du cancer de la prostate par agressivité en IRM multiparamétrique". Thesis, Lyon, 2022. http://theses.insa-lyon.fr/publication/2022LYSEI008/these.pdf.
Texto completoProstate cancer (PCa) is the most frequently diagnosed cancer in men in more than half the countries in the world and the fifth leading cause of cancer death among men in 2020. Diagnosis of PCa includes multiparametric magnetic resonance imaging acquisition (mp-MRI) - which combines T2 weighted (T2-w), diffusion weighted imaging (DWI) and dynamic contrast enhanced (DCE) sequences - prior to any biopsy. The joint analysis of these multimodal images is time demanding and challenging, especially when individual MR sequences yield conflicting findings. In addition, the sensitivity of MRI is low for less aggressive cancers and inter-reader reproducibility remains moderate at best. Moreover, visual analysis does not currently allow to determine the cancer aggressiveness, characterized by the Gleason score (GS). This is why computer-aided diagnosis (CAD) systems based on statistical learning models have been proposed in recent years, to assist radiologists in their diagnostic task, but the vast majority of these models focus on the binary detection of clinically significant (CS) lesions. The objective of this thesis is to develop a CAD system to detect and segment PCa on mp-MRI images but also to characterize their aggressiveness, by predicting the associated GS. In a first part, we present a supervised CAD system to segment PCa by aggressiveness from T2-w and ADC maps. This end-to-end multi-class neural network jointly segments the prostate gland and cancer lesions with GS group grading. The model was trained and validated with a 5-fold cross-validation on a heterogeneous series of 219 MRI exams acquired on three different scanners prior prostatectomy. Regarding the automatic GS group grading, Cohen’s quadratic weighted kappa coefficient (κ) is 0.418 ± 0.138, which is the best reported lesion-wise kappa for GS segmentation to our knowledge. The model has also encouraging generalization capacities on the PROSTATEx-2 public dataset. In a second part, we focus on a weakly supervised model that allows the inclusion of partly annotated data, where the lesions are identified by points only, for a consequent saving of time and the inclusion of biopsy-based databases. Regarding the automatic GS group grading on our private dataset, we show that we can approach performance achieved with the baseline fully supervised model while considering 6% of annotated voxels only for training. In the last part, we study the contribution of DCE MRI, a sequence often omitted as input to deep models, for the detection and characterization of PCa. We evaluate several ways to encode the perfusion from the DCE MRI information in a U-Net like architecture. Parametric maps derived from DCE MR exams are shown to positively impact segmentation and grading performance of PCa lesions
Loubrie, Stéphane. "IRM multi-paramétrique du muscle squelettique dans le contexte de la sarcopénie et de la fragilité". Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0320.
Texto completoGeriatric Frailty Syndrome is defined as a clinically recognizable condition of increased vulnerability resulting from decline associated with aging. Although this diagnosis is set up following physical tests, the condition of the muscles is not specifically studied, whereas one of the main factors of the frailty condition is sarcopenia. In order to pursue in this direction, it was decided to study the muscles through Magnetic Resonance Imaging (MRI), a non-invasive method enabling longitudinal follow-up and offering high spatial resolutions. Given the need to develop new MRI methods for the exploration of muscles, animal models, and more particularly the rats, were studied as they enable to mimic many pathologies.First, an MRI-compatible bed was developed in order to place the rat in the scanner, while enabling the electrostimulation of the gastrocnemius muscle. This bed also contains a foot pedal associated with a pressure transducer in order to measure the force exerted by the stimulated hind limb. In addition, an electronic card enabling synchronization between the electrostimulator and the MRI sequences was developed.The multi-parametric measurement of muscle during exercise was carried out after the development of a radial-encoded Look-Locker sequence, a Multi-Slice Multi-Echo sequence and 31P phosphorus spectroscopy to measure T1 relaxation times, T2 and ATP/PCr consumption.Due to these methodological developments, no movement artefact was detected on the images, which enabled to apply these sequences to a comparative study of muscular effort between young and old rats. These methods have shown that, unlike T1, T2 varies with the intensity of stimulation. Spectroscopy also permitted to establish a correlation between the variations of T2 with the consumption of PCr.Moreover, a clinical study in humans enabled to measure the T2 of muscle in frailty patients and to assess correlations with age-related cognitive degenerations
Palard, Xavier. "Quantification multiparamétrique par TEP à la 18F-Choline et IRM dans le cancer de la prostate". Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1B058.
Texto completoResearch question: Do the functional parameters derived by 18F-Choline (FCH) Positon Emission Tomography (PET) and Magnetic Resonance Imaging (MRI) add informations to characterize the aggressiveness of prostate cancer? Objectives: The first objective of this work was (i) to enhance a potential link between quantitative parameters extracted by FCH PET and clinicopathological parameters in prostate cancer. Then, after this preliminary study, in order to optimize the quantification of the FCH influx with a kinetic analysis, the second objective was (ii) to optimize the exam protocol of the FCH PET early acquisition. Finally, the last objective was (iii) to enhance a potential link between quantitative parameters extracted by FCH PET and quantitative parameters extracted by multiparametric MRI in prostate cancer. Results: For the first step (i), we compared FCH PET quantitative parameters and clinicopathological parameters extracted from 61 patients referred to the nuclear medicine department to perform an FCH PET/ CT with newly histologically proven prostate cancer and before any treatment The FCH influx measured using kinetic analysis was higher for patients with a Gleason score ≥ 4+3 than for patients with a Gleason score < 4 + 3. Concerning the second step (ii), firstly, we compared the contrast to noise ratio of 77 prostatic cancer lesions at 5 minutes and 10 minutes post-injection in order to optimize the length of the early FCH PET acquisition. No significant difference was observed. Secondly, we sought to define an optimal time sampling of the early FCH PET acquisition comparing 7 different time samplings with a FCH influx as objective extracted from 37 prostatic cancer lesions. The 12x5”-8x30” time sampling was selected. For the last step of this work (iii), we compared FCH PET and multiparametric MRI quantitative parameters extracted from 14 prostatic cancer lesions. The FCH influx was moderately correlated to the vessel permeability measured by the volume transfert constant of gadolinium (r = 0.55). Conclusion: The FCH influx extracted from the early FCH PET acquisition using kinetic analysis seems to be linked to the tumoral differentiation of prostatic cancers. This FCH influx seems also linked to the vessel permeability. However, due to the moderate degree of correlation, these two imaging parameters reflect two different processes. To confirm the results obtained in this work, other studies are needed to enhance the role of the functional parameters derived by FCH PET and multiparametric MRI as biomarkers for prostate cancer
Jaouen, Tristan. "Caractérisation du cancer de la prostate de haut grade à l’IRM multiparamétrique à l’aide d’un système de diagnostic assisté par ordinateur basé sur la radiomique et utilisé comme lecteur autonome ou comme second lecteur". Electronic Thesis or Diss., Lyon, 2022. http://www.theses.fr/2022LYSE1140.
Texto completoWe developed a region of interest-based (ROIs) computer-aided diagnosis system (CAD) to characterize International Society of Urological Pathology grade (ISUP) ≥2 prostate cancers at multiparametric MRI (mp-MRI). Image parameters from two multi-vendor datasets of 265 pre-prostatectomy and 112 pre-biopsy MRIs were combined using logistic regression. The best models used the ADC 2nd percentile (ADC2) and normalized wash-in rate (WI) in the peripheral zone (PZ) and the ADC 25th percentile (ADC25) in the transition zone (TZ). They were combined in the CAD system. The CAD was retrospectively assessed on two multi-vendor datasets containing respectively 158 and 105 pre-biopsy MRIs from our institution (internal test dataset) and another institution (external test dataset). Two radiologists independently outlined lesions targeted at biopsy. The Prostate Imaging-Reporting and Data System version 2 (PI-RADSv2) score prospectively assigned at biopsy and the CAD score were compared to biopsy findings. At patient level, the areas under the Receiver Operating Characteristic curve (AUC) of the PI-RADSv2 score were 82% (95% CI: 74-87) and 85% (95% CI: 79-91) in the internal and external test datasets respectively. For both radiologists, the CAD score had similar AUC results in the internal (82%, 95% CI: 76-89, p=1; 84%, 95% CI: 78-91, p=1) and external (82%, 95% CI: 76-89, p=0.82; 86%, 95% CI: 79-93, p=1) test datasets. Combining PI-RADSv2 and CAD findings could have avoided 41-52% of biopsies while missing 6-10% of ISUP≥2 cancers. The CAD system confirmed its robustness showing good discrimination of ISUP ≥2 cancers in a multicentric study involving 22 different scanners with highly heterogeneous image protocols. In per patient analysis, the CAD and the PI-RADSv2 had similar AUC values (76%, 95% CI: 70-82 vs 79%, 95% CI: 73-86; p=0.34) and sensitivities (86%, 95% CI: 76-96 vs 89%, 95% CI: 79-98 for PI-RADSv2 ≥4). The specificity of the CAD (62%, 95% CI: 53-70 vs 49%, 95% CI: 39-59 for PI-RADSv2 ≥4) could be used to complement the PI-RADSv2 score and potentially avoid 50% of biopsies, while missing 13% of ISUP ≥2 cancers. These findings were very similar to those reported in the single center test cohorts. Given its robustness, the CAD could then be exploited in more specific applications. The CAD first provided good discrimination of ISUP ≥2 cancers in patients under Active Surveillance. Its AUC (80%, 95% CI: 74-86) was similar to that of the PI-RADS score prospectively assigned by specialized uro-radiologists at the time of biopsy (81%, 95% CI: 74-87; p=0.96). After dichotomization, the CAD was more specific than the PI-RADS ≥3 (p<0.001) and the PI-RADS ≥4 scores (p<0.001). It could offer a solution to select patients who could safely avoid confirmatory or follow-up biopsy during Active Surveillance (25%), while missing 5% of ISUP≥2 cancers. Finally, the CAD was tested with the pre-prostatectomy mp-MRIs of 56 Japanese patients, from a population which is geographically distant from its training population and which is of interest because of its low prostate cancer incidence and mortality. The CAD obtained an AUC similar to the PI-RADSv2 score assigned by an experience radiologist in the PZ (80%, 95% CI: 71-90 vs 80%, 95% CI: 71-89; p=0.886) and in the TZ (79%, 95% CI: 66-90 vs 93%, 95%CI: 82-96; p=0.051). These promising and robust results across heterogeneous datasets suggest that the CAD could be used in clinical routine as a second opinion reader to help select the patients who could safely avoid biopsy. This CAD may assist less experience readers in the characterization of prostate lesions
Lemasson, Benjamin. "Evaluation de l'IRM multiparamétrique comme indicateur de l'effet de thérapies anti-angiogéniques sur des modèles de gliomes implantés chez le rat". Phd thesis, Grenoble, 2010. http://www.theses.fr/2010GRENV002.
Texto completoIn the context of glioma, MRI plays an extremely important role in the evaluation of new anti-tumor therapies in preclinical research for their development and in clinical routine to monitor patients under thérapy. The aim of this thesis was to determine of one or several MRI parameters can be used as biomarker of therapy effects on glioma models in rats. We evaluated different MRI parameters (ADC : apparent diffusion coefficient of water, BVf : blood volume fraction and VSI : vessel size index) at a same growth stage of 6 glioma models, and in a longitudinal follow-up of 2 glioma models. These 2 studies have validated these MRI parameters (robustness of the techniques and biological validation). In a 3rd study, we followed the evolution of these parameters plus vessel permeability to a contrast agent during follow-up of 2 therapies (chemotherapy and antiangiogenic). In the last study we followed by MRI (ADC, BVf, VSI, quantitative permeability of two different sized contrast agents and boold oxygen saturation (lSO2)) the effect of 2 therapies (antiangiogenic and synchrotron radiotherapy) applied alone or combined on a glioma model. Multiparametric MRI as presented in the various studies appears as an imaging modality with great potential for the evaluation of new drugs on brain tumors in preclinical studies. The transfert to clinic of the new MRI techniques used in this thesis (VSI, vessel permeability to 2 contrast agents and lSO2) can also be envisaged in the near future
Lemasson, Benjamin. "Evaluation de l'IRM multiparamétrique comme indicateur de l'effet de thérapies anti-angiogéniques sur des modèles de gliomes implantés chez le rat". Phd thesis, Université de Grenoble, 2010. http://tel.archives-ouvertes.fr/tel-00908915.
Texto completoHoang, Dinh Au. "Développement et évaluation des paramètres quantitatifs de l’IRM de la prostate". Electronic Thesis or Diss., Lyon 1, 2015. http://www.theses.fr/2015LYO10210.
Texto completoThe purpose of this thesis is to develop and evaluate the quantitative methods of multiparametric MRI of prostate in discriminating Gleason score (GS) ≥7 cancers. We suppose that the quantitative parameter of MRI could help standardizer the diagnostic, reduce the inter-lecture and/ or inter-institution variation in diagnostic of prostate cancer. This thesis is divided into three chapters. The firs chapter, entilted « Quantitative T2 MRI of prostate » is a retrospective study on a database of prostate cancer patients before radical prostatectomy. The second chapter, entilted « Multi-parametric Quantitative MRI of prostate » is also a retrospective study before radical prostatectomy. The third chapter, entitled « MR elastography of prostate by transperineal approach », is an experimental study. Our first study shows that T2 value is robust between machines of different constructors. T2 value is significant predictor, but of weak performance, of aggressively cancer of prostate at 3T. Our second study shows that the combination of ADC_10th percentile with Time-to-peak (TTP) improved the diagnosis performance, and this model is also robust between two machines of different constructors. Our third study shows the initial results on elasticity of the prostate. These results show that MRI elastography of prostate at high excitation frequency (>100 Hz) by trans-perineale approach was feasible. The elastography may, in the future, be integrated in quantitative multi-parametric MRI to improve the diagnosis performance
Lehaire, Jérôme. "Détection et caractérisation du cancer de la prostate par images IRM 1.5T multiparamétriques". Electronic Thesis or Diss., Lyon, 2016. http://www.theses.fr/2016LYSE1174.
Texto completoProstate cancer is the most frequent and the fourth leading cause of mortality in France. Actual diagnosis methods are often insufficient in order to detect and precisely locate cancer. Multiparametrics MRI is now one of the most promising method for accurate follow-up of the disease. However, the visual interpretation of MRI is not easy and it is shown that there is strongvariability among expert radiologists to perform diagnosis, especially when MR sequences are contradictory. Under these circumstances, a strong interest is for Computer-aided diagnosis systems (CAD) aiming at assisting expert radiologist in their final decision. This thesis presents our work toward the conception of a CADe which final goal is to provide a cancer probability map to expertradiologist. This study is based on a rich dataset of 49 patients made of T2w, dynamic and diffusion MR images. The ground truth was obtained through strict process of annotations and correlation between histology and MRI. This thesis focuses both for cancer detection and characterization in order to provide a cancer probability map correlated to cancer aggressiveness (Gleason score). To that end we used a dictionary learning method to extract new features to better characterize cancer aggressiveness signatures as well as image features. Those features are then used as an input to Support Vector Machines (SVM) and Logistic Regression (LR) classifiers to produce a cancer probability map. We then focused on discriminating agressive cancers (Gleason score >6) from other tissues and provided an analysis of the correlation between cancer aggressiveness and probabilities. Our work conclude on a strong capability to distinguish agressive cancer from other tissues but fails to precisely distinguish different grades of cancers