Дисертації з теми "Cancer du sein – Imagerie par résonance magnétique"
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Plassat, Vincent. "Liposomes superparamagnétiques stabilisés stériquement pour l'imagerie IRM et la thérapie des cancers à tumeurs solides : étude in vitro et in vivo de la vectorisation magnétique d'un anti-ostrogène sur un modèle tumoral de cancer du sein." Paris 11, 2010. http://www.theses.fr/2010PA114841.
This work concerns the use of PEG-ylated superparamagnetic liposomes (MFLs) for magnetic targeting of the anti-estrogen RU 58668 towards breast cancer tumors after intravenous injection. Pharmacokinetic parameters and biodistribution of MFLs were first studied on mice, especially highlighting long-circulating behaviour of MFLs with a 12. 5-hour half-life. Incorporation of the anticancer drug leads to stable mixed vesicles (RU-MFLs) as shown by DSC and XRD. In vitro investigations, mainly by confocal fluorescence and electron microscopies, magnetophoresis and transcription assay, reveal that RU-MFLs penetrate MCF-7 cells through endocytosis as intact structures and the association yield is increased by applying a magnetic field gradient to the cells. The in-vivo study on MCF-7 tumor xenografted on mice definitively validates the effectiveness of magnetic targeting via the vascular compartment from MR or fluorescence imaging, histological and immunohistochemical analyzes and biodistribution insight. RU-MFLs appear as a potentially interesting tool for estrogen-dependent breast cancer treatment with the advantage to combine therapy and MRI diagnosis
Saillard-Renault, Christine. "IRM et microcalcifications mammaires : à propos de 100 cas." Montpellier 1, 1996. http://www.theses.fr/1996MON11135.
Delbany, Maya. "Acquisition IRM optimisée en vue du dépistage du cancer du sein." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0018.
Diffusion-weighted imaging (DWI) is a promising tool to increase the specificity of MRI for breast cancer screening. However, the field of view covering the breasts makes the DWI at high resolution difficult and the images obtained have low signal-to-noise ratios (SNR). The current DWI techniques are limited by the spatial resolution, mainly a slice thickness greater than or equal to 3 mm. In this work, an isotropic DWI method was developed to obtain high resolution isotropic images (1x1x1 mm3) covering the entire breast. These images are obtained by combining: (i) a readout-segmented DW-EPI sequence (rs-EPI), with several segments of k-space and echo navigator providing high in-plane resolution, (ii) a super-resolution (SR) strategy, which consists of acquiring three datasets with thick slices (3 mm) and 1mm-shifts in the slice direction, (iii) and combining them into a 1x1x1 mm3 dataset using a dedicated reconstruction. Several SR reconstruction schemes were investigated, based on different regularizations. The proposed SR strategy was compared to native 1x1x1 mm3 acquisitions (i.e. with 1 mm slice thickness) on eight healthy subjects, and synthetics phantoms. To validate the SR method, we used several methods: Monte Carlo simulations, SNR measurements and sharpness metrics, the apparent diffusion coefficient (ADC) values in normal breast tissue and breast diffusion/resolution phantom were also compared. A new clinical research protocol is proposed to evaluate the effectiveness of the high resolution diffusion sequence on breast cancer screening. The aim of this protocol is to replace the contrast-enhanced perfusion by the diffusion sequence for screening
Ayestaran-Kraus, Christine. "Intérêt de l'IRM dans la surveillance des patientes traitées pour un cancer du sein, de façon conservatrice." Bordeaux 2, 1999. http://www.theses.fr/1999BOR23002.
Rousseau, Loi͏̈c. "Etude des rehaussements du sein en IRM (à propos de 137 cas issus d'une série de 260 patientes) en pratique médicale courante dans une consultation des maladies du sein." Montpellier 1, 1996. http://www.theses.fr/1996MON11040.
Bertino, Catherine. "Fraction volumique extracellulaire et vascularisation des tumeurs mammaires : évaluation par relaxométrie dynamique en imagerie de résonance magnétique." Toulouse 3, 2003. http://www.theses.fr/2003TOU30133.
Delbany, Maya. "Acquisition IRM optimisée en vue du dépistage du cancer du sein." Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0018/document.
Diffusion-weighted imaging (DWI) is a promising tool to increase the specificity of MRI for breast cancer screening. However, the field of view covering the breasts makes the DWI at high resolution difficult and the images obtained have low signal-to-noise ratios (SNR). The current DWI techniques are limited by the spatial resolution, mainly a slice thickness greater than or equal to 3 mm. In this work, an isotropic DWI method was developed to obtain high resolution isotropic images (1x1x1 mm3) covering the entire breast. These images are obtained by combining: (i) a readout-segmented DW-EPI sequence (rs-EPI), with several segments of k-space and echo navigator providing high in-plane resolution, (ii) a super-resolution (SR) strategy, which consists of acquiring three datasets with thick slices (3 mm) and 1mm-shifts in the slice direction, (iii) and combining them into a 1x1x1 mm3 dataset using a dedicated reconstruction. Several SR reconstruction schemes were investigated, based on different regularizations. The proposed SR strategy was compared to native 1x1x1 mm3 acquisitions (i.e. with 1 mm slice thickness) on eight healthy subjects, and synthetics phantoms. To validate the SR method, we used several methods: Monte Carlo simulations, SNR measurements and sharpness metrics, the apparent diffusion coefficient (ADC) values in normal breast tissue and breast diffusion/resolution phantom were also compared. A new clinical research protocol is proposed to evaluate the effectiveness of the high resolution diffusion sequence on breast cancer screening. The aim of this protocol is to replace the contrast-enhanced perfusion by the diffusion sequence for screening
Poujol, Julie. "Techniques d'acquisitions et reconstructions IRM rapides pour améliorer la détection du cancer du sein." Electronic Thesis or Diss., Université de Lorraine, 2017. http://www.theses.fr/2017LORR0143.
Breast cancer is nowadays the first cause of female cancer and the first cause of female death by cancer. Breast MRI is only performed in second intention when other imaging modalities cannot lead to a confident diagnosis. In high risk women population, breast MRI is recommended as an annual screening tool because of its higher sensitivity to detect breast cancer. Breast MRI needs contrast agent injection to visualize enhancing lesions and the diagnosis is mostly based on morphological analysis of these lesions. Therefore, an acquisition with high spatial resolution is needed. Despite the use of conventional MRI acceleration techniques, the volume of data to be acquired remains quite large and the temporal resolution of the exam is around one minute. This low temporal resolution may be the cause of the low specificity of breast MRI exam. Breast MRI with higher temporal resolution will allow the use of pharmacokinetic models to access physiological parameters and lesion specifications. The main aim of this work is to develop a MRI sequence allowing a flexible use of the acquired data at the reconstruction stage. On the one hand, the images can be reconstructed with a conventional reconstruction like the protocol used in clinical routine. On the other hand, the new MRI sequence will also allow the reconstruction of images with a higher temporal resolution allowing the use of pharmacokinetic models. The development of this sequence was done by modifying the acquisition order in the Fourier domain. A random acquisition of the Fourier domain will allow the reconstruction of sub-sampled domains acquired faster. We paid attention to fat suppression efficiency with this new Fourier domain acquisition order. Tests were performed on phantom, female volunteers and patients. These tests showed that the random acquisition did not impact the quality of images (MRI signal and lesion morphology) obtained by conventional reconstruction thus allowing the conventional diagnosis. The reconstructions of the sub-sampled Fourier domains were made using Compressed Sensing reconstructions to remove sub-sampling artifacts. These reconstructions were developed and tested on digital phantoms reproducing breast MRI. The potential of this new MRI acquisition was tested on an artificial enhancing breast lesion developed especially for this purpose
Balleyguier, Corinne. "Elastographie-IRM pour le diagnostic et la caractérisation des lésions du sein." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00824882.
Boughdad, Sarah. "Contributions of radiomics in ¹⁸F-FDG PET/CT and in MRI in breast cancer." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS500.
Breast cancer is a common disease for which ¹⁸F-FDG PET/CT and breast MRI are frequently performed in routine practice. However, the different information provided by each of these imaging techniques are currently under-exploited. Indeed, in routine the interpretation of these scans is mainly based on visual analysis whereas the « quantitative » analysis of PET/CT data is generally limited to the sole use of the SUVmax while in breast MRI, simple parameters to characterize tumor enhancement after injection of contrast medium are used. The advent of PET/MRI machines, calls for an evaluation of the contribution of a more advanced quantification of each of the modalities separately and in combination in the setting of breast cancer. This is along with the concept of « Radiomics » a field currently expanding and which consists in extracting many quantitative characteristics from medical images used in clinical practice to decipher tumor heterogeneity or improve prediction of prognosis. The aim of our work was to study the contribution of radiomic data extracted from ¹⁸F-FDG PET and MRI imaging with contrast injection to characterize tumor heterogeneity in breast cancer taking into account the different molecular subtypes of breast cancer, namely luminal (Lum A, Lum B HER2- and Lum B HER2 +), triple-negative and HER2 + tumors. In this context, we focused on the prediction of prognosis in patients treated with neo-adjuvant chemotherapy. The influence of physiological variations such as age on the calculation of radiomic data in normal breast and breast tumors separately was also explored, as well as the multi-center variability of radioman features. Radiomic features were extracted using the LiFex software developed within IMIV laboratory. The patient database used for the studies were all retrospective data. We reported for the first time the influence of age on the values of radiomic features in healthy breast tissue in patients recruited from 2 different institutions but also in breast tumors especially those with a triple-negative subtype. Similarly, significant associations between the radiomic tumor phenotype in PET and MRI imaging and well-established prognostic factors in breast cancer have been identified. In addition, we showed a large variability in the PET « radiomic profile » of breast tumors with similar breast cancer subtype suggesting complementary information within their metabolic phenotype defined by radiomic features. Moreover, taking into account this variability has been shown to be of particular interest in improving the prediction of pathological response in patients with triple-negative tumors treated with neoadjuvant chemotherapy. A peri-tumoral breast tissue region satellite to the breast tumor was also investigated and appeared to bear some prognostic information in patients with Lum B HER2- tumors treated with neoadjuvant chemotherapy. In MR, we demonstrated the need to harmonize the methods for radiomic feature calculation. Overall, we observed that radiomic features derived from MR were less informative about the molecular features of the tumors than radiomic features extracted from PET data and were of lower prognostic value. Yet, the combination of the enhanced tumor volume in MR with a PET radiomic feature and the tumor molecular subtype yielded enhanced the accuracy with which response to neoadjuvant therapy could be predicted compared to features from one modality only or molecular subtype only
Oldrini, Guillaume. "Dépistage en IRM mammaire." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0282/document.
Breast MRI has a prominent place in breast imaging. Its wider use is limited in particular by its cost and the limited number of machines. We have worked on several aspects of this problem. In a first step, we changed the positioning from procubitus to decubitus. This showed that the decubitus allowed a better topographic correlation of the lesions with the ultrasound and was better tolerated by the patients. In a second step, we studied the factors of reduction of the acquisition time via the sequences with high temporal resolution and an abbreviated protocol. These changes should make it easier for patients to access MRI, reduce costs while maintaining the same sensitivity and specificity values as the standard protocol
Poujol, Julie. "Techniques d'acquisitions et reconstructions IRM rapides pour améliorer la détection du cancer du sein." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0143/document.
Breast cancer is nowadays the first cause of female cancer and the first cause of female death by cancer. Breast MRI is only performed in second intention when other imaging modalities cannot lead to a confident diagnosis. In high risk women population, breast MRI is recommended as an annual screening tool because of its higher sensitivity to detect breast cancer. Breast MRI needs contrast agent injection to visualize enhancing lesions and the diagnosis is mostly based on morphological analysis of these lesions. Therefore, an acquisition with high spatial resolution is needed. Despite the use of conventional MRI acceleration techniques, the volume of data to be acquired remains quite large and the temporal resolution of the exam is around one minute. This low temporal resolution may be the cause of the low specificity of breast MRI exam. Breast MRI with higher temporal resolution will allow the use of pharmacokinetic models to access physiological parameters and lesion specifications. The main aim of this work is to develop a MRI sequence allowing a flexible use of the acquired data at the reconstruction stage. On the one hand, the images can be reconstructed with a conventional reconstruction like the protocol used in clinical routine. On the other hand, the new MRI sequence will also allow the reconstruction of images with a higher temporal resolution allowing the use of pharmacokinetic models. The development of this sequence was done by modifying the acquisition order in the Fourier domain. A random acquisition of the Fourier domain will allow the reconstruction of sub-sampled domains acquired faster. We paid attention to fat suppression efficiency with this new Fourier domain acquisition order. Tests were performed on phantom, female volunteers and patients. These tests showed that the random acquisition did not impact the quality of images (MRI signal and lesion morphology) obtained by conventional reconstruction thus allowing the conventional diagnosis. The reconstructions of the sub-sampled Fourier domains were made using Compressed Sensing reconstructions to remove sub-sampling artifacts. These reconstructions were developed and tested on digital phantoms reproducing breast MRI. The potential of this new MRI acquisition was tested on an artificial enhancing breast lesion developed especially for this purpose
Berenguer-Garcia, Françoise. "Métastases intradurales, à propos de quatre observations : revue de la littérature." Bordeaux 2, 2001. http://www.theses.fr/2001BOR2M010.
Chaulin, Bertrand. "Imagerie par résonance magnétique dans le bilan d'extension du cancer de la prostate aux vésicules séminales." Bordeaux 2, 1991. http://www.theses.fr/1991BOR23003.
Martin, Jean-Michel. "IRM du sein : valeur et limites des produits du gadolinium : à propos de 170 cas." Montpellier 1, 1990. http://www.theses.fr/1990MON11270.
Fournier-Dujardin, Laure. "Imagerie multimodalité de l'angiogenèse tumorale." Paris 11, 2005. http://www.theses.fr/2005PA112345.
Angiogenesis is the formation of new vessels induced by tumours to allow its growth and expansion. It has become the target of a new class of drugs: anti-angiogenic agents. These therapies rarely induce a decrease tumour size. It is therefore necessary to develop new techniques to evaluate functional characteristics of tumours, reflecting their angiogenic status. This purpose of this work was to detect and characterize liver and breast tumours in animal models and in women by quantifying their microvascular characteristics, and to follow anti-angiogenic treatment in human tumours implanted in animals. Several techniques were used in this work. Contrast-enhanced dynamic imaging using Computed Tomography and Magnetic Resonance Imaging yielded parameters reflecting tumour microcirculation, allowing detection and characterization of tumours, and following the effects of therapeutic agents. Optical imaging, which uses light as a diagnostic tool, is still experimental, but it offers new possibilities to define physiological parameters for tissue characterization
Pasquier, David. "Imagerie par Résonance Magnétique et radiothérapie conformationnelle : caractérisation de l'Imagerie par Résonance Magnétique pour son utilisation dans l'établissement des plans de traitement en radiothérapie conformationnelle : développement et évaluation d'un outil de délinéation automatique et semi-automatique des volumes d'intérêt pour la radiothérapie conformationnelle du cancer prostatique." Lille 2, 2006. http://www.theses.fr/2006LIL2S045.
Radiotherpy is a curative treatment of malignant tumours. Radiotherapy techniques considerably evolved last years with the increasing integration of medical images in conformal radiotherapy. This technique makes it possible to elaborate a complex ballistics conforming to target volume ans sparing healthy tissues. The examination currently used to delineate volumes of interest is Computed Tomography (CT), on account of its geometrical precision and the information that it provides on electronic densities needed to dose calculation. Magnetic Resonance Imaging (MRI) ensures a more precise delineation of target volumes in many locations, such as pelvis and brain. For pelvic tumours, the use of MRI needs image registration, which complicates treatment planning and poses the problem of the lack of in vivo standard method of validation. The obstacles in the use of MRI alone on treatment planning were evaluated. Neither geometrical distorsion linked with the system and the patient nor the lack of information on electronic densities represent stumbling obstacles. Distortion remained low even in edge of large field of view on medern machines. The assignment of electronic densities to bone structures and soft tissues in MR images permitted to obtain equivalent dosimetry to that carried out on the original CT, with a good reproducibility and homogeneous distribution within target volume. The assignment of electronic densities could not be carried out using 20 MV photons and suitable ballistics. The development of Image Guided Radiotherapy could facilitate the use of MRI alone in treatment planning. Target volumes and organ at risk delineation is a time consuming task in radiotherapy planning. We took part in the development and evaluated a method of automatic and semi automatic delineation of volumes of interst from MRI images for prostate cancer radiotherapy. For prostate and organ at risk automatic delineation an organ model-based method and a seeded region growing method were used respectively. Our results are reproducible with minimal repercussion on dosimetry
Le, Guen Virginie. "Lésions bénignes du sein et IRM : valeurs et limites en pratique médicale courante : à propos de 240 cas." Montpellier 1, 1996. http://www.theses.fr/1996MON11046.
Le, Bastard Eric. "Imagerie par résonance magnétique du cancer de la prostate localisé : corrélations histopathologiques à propos de 13 prostatectomies totales." Bordeaux 2, 1989. http://www.theses.fr/1989BOR23034.
Valentin, Fabienne. "Evaluation de la place de l'IRM dynamique dans la prise en charge des cancers du col utérin." Bordeaux 2, 2000. http://www.theses.fr/2000BOR23100.
Detappe, Alexandre. "AGuIX, une nanoparticule théranostique pour améliorer la radiothérapie guidée par l’image : preuve de concept appliquée au cancer du pancréas." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1032/document.
Previous studies demonstrated AGuIX ability to act as an efficient radiosensitizer under the presence of preclinical radiations or monoenergetic radiation beams for multiple cancer models. The preclinical irradiation (220 kV) has been shown effective in activating high atomic number (Z) nanoparticles. The energy peak is close to the k-edge of the different high-Z elements used (50.2 keV for the gadolinium), leading to a strong photoelectric effect. Auger electrons generation and biological effects occur afterwards creating a local dose enhancement. However, clinical treatments use a higher energy beam (>6 MV). At these energy ranges, the photoelectric probability is less important, decreasing the direct interaction of the nanoparticles with the incoming photons. We performed a proof of concept on a pancreatic tumor model, known for its low survival rates, with preclinical and clinical radiation beams to evaluate the efficacy of the AGuIX. To increase the efficacy of the clinical radiation beam without modifying the nanoparticle structure in order to obtain a dose enhancement close to the one observed with the preclinical beam, we evaluated key clinical beam parameters to understand and increase the mechanisms of interaction between the incident photons and the high-Z nanoparticles. Hence, we evaluated analytically the impact of the radiation beam under different conditions of irradiation, confirming the potential of the AGuIX with a preclinical beam, and finally shown their significant efficacy under a clinical setup. This study is the first to evaluate the potential of a high-Z nanoparticle to act as radiosensitizer following low dose intravenous injections
Rouviere, Olivier. "Apport de l'imagerie au traitement du cancer de prostate par ultrasons focalises de haute intensité." Lyon 1, 2003. http://www.theses.fr/2003LYO10121.
Durand, Matthieu. "Imagerie expérimentale ex vivo de haute résolution à 7 tesla du cancer localisé de la prostate." Thesis, Lille 2, 2019. http://www.theses.fr/2019LIL2S015/document.
Prostate MRI at 1.5T or 3T is the best imaging modality for tumor detection. Weinvestigated high resolution MRI at 7T on prostate specimen tissue to improve spatialresolution and prostate cancer detection.First part of experiments consisted of setting up new imaging protocol with 7T MRI onex vivo prostatic tissue. Imaging was carried out on all or part of specimen from radicalprostatectomy of patients or prostate harvested from deceased organ donors.Collected data resulted in new protocol parameters for fast spin echo needed to yielda spatial resolution of 60 X 60 X 90 μm3. High spatial resolution imaging was used toidentify relevant morphological structures for characterization of the prostate gland andtumor as compared to histology.Second part of work was done with whole gland imaging at 7T of radical prostatectomyspecimens of patients. Imaging protocol was based on the outcomes from the first partof experiments and consisted in T2W with high resolution of 130 X130 X195 μm3,diffusion and ADC map. Two independent and blinded reviewers were in charge ofimaging quality assessment and tumor detection. Overall quality was great with goodagreement between the two reviewers. Correlation study for prostate cancer detectionwith the corresponding H&E was of 70%, 80%, 79% and 72% for sensitivity, specificity,positive predictive value and negative predictive value, respectively.We measured the resolution of 7T MRI of ex vivo prostatic tissue, and it’s benefits intumor detection. New semiology should be designed at 7T to improve theunderstanding of prostatic tissue in further experiments. In future, these findings canbe extrapolated to carry out in 7T MRI of in vivo prostate gland
Deruelle, Tristan. "Magnetic Resonance Elastography : towards prostate cancer imaging and slow compression wave imaging in softtissues." Electronic Thesis or Diss., Lyon, 2022. http://www.theses.fr/2022LYSE1068.
Prostate cancer is the second most prevalent cancer in men worldwide. It is suspected when the PSA density is high or/and the superficial prostate feels hard during digital rectal examination. Multiparametric MRI is now recommended prior biopsy when detecting for cancer. However, image interpretation is challenging, even for specialists, and brings many false-positive. Elastography is a technique to assess tissue stiffness by inducing small vibrations. It could provide a 3D map of the stiffness of the prostate. We believe that MR elastography could complement the current multiparametric MRI. Given prostate location and consitution, wave propagation is difficult though. The current work presents the design of a non-invasive wave generation device for the prostate. Then, a new field separation algorithm is presented. This algorithm provides a better estimation of the stiffness, and the correction of artefact generated by common vibrators. Finally, this algorithm can have applications in porous media. Indeed, in poro-elastic materials, a slow compression wave propagates. We observe such a wave in an agar gel, in a foam phantom, and in vivo in human kidney graft. In addition to the classic shear wave velocity estimation, it is now possible to estimate the compression wave velocity. This is an additional piece of information that the operator can use in its diagnostic. In the future, more porous parameters could be derived
Salomir, Rares. "Local hyperthermia by MRI-guided focused ultrasound : fast MR-thermometry and on-line temperature control : feasibility studies of tumor thermal ablation." Bordeaux 1, 2001. http://www.theses.fr/2001BOR12418.
Verret, Jean-Marie. "Apport d'un capteur endoluminal pour l'observation de la paroi colorectale par imagerie et spectrométrie de résonance magnétique." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10343.
The colorectal pathologies a major public health problem, indeed it is the second most lethal cancer and its incidence is second amongst all cancers. To performer the initial assessment of the colorectal cancer (CRC), Magnetic Resonance Imaging (MRI) is, at this moment in time, the gold standard for the assessment of the latest stages of CRC. However, despite significant progress, external phased array coils do not allow a sufficient spatial resolution for the observation of the colorectal wall. In this prospect, the use of an endoluminal coil for the MRI observation of the earliest stages of the CRC seems to present an interest. Thus, in the framework of this PhD, the aim was to propose and develop a rigid endoluminal coil suited for the observation of the terminal part of the digestive tract (rectum and sigmoid).First, the geometry of the endoluminal coil was optimized to minimize the non-uniformities in radial sensitivity. Thus, it was show that two current loops forming angulated with a 50° to 70° allow for optimal radial sensitivity uniformity. This could potentially allow for an increase in specificity and sensitivity of an endoluminal MR (Magnetic Resonance) exam. Furthermore, the safety of the endoluminal coil with respect to the radiofrequency (RF) heating was assessed. And, as demonstrated in the literature, the addition of RF traps allows for a reduction of the RF heating under the limits as determined by the IEC-60601 norm (below 1°C heating induced by the coil and reception cable presence). Reference RF traps and miniaturized RF traps, suited for the insertion through the rectum of the patient, were designed, built and assessed both on the benchmark and on the MR scanner DV MR 750 3T (General Electric Healthcare, Milwaukee, WI, US). The experiments were designed to maximize RF heating by an adequate choice of cable length, reception cable path, and acquisition sequence. Then, the design of the endoluminal coil was optimized to allow the acquisition of diffusion MRI images and magnetic resonance spectra, techniques which are particularly sensitive to the magnetic field (B0) inhomogeneities. Thus, the susceptibility effect occurring at the interface between the endoluminal coil and surrounding tissues of the rectal wall will deter significantly the performances of these techniques. A susceptibility matched endoluminal coil was thus developed, using UltemTM as a support for the coil, and was compared to a reference endoluminal coil for the acquisition of magnetic resonance spectra. Finally, the coil was modified in order to acquire both hydrogen magnetic resonance spectra and phosphorus magnetic resonance spectra, while keeping the same geometry. This last development was assessed on the bench and opens the way towards further experiments on phantom and, eventually, in vivo experiments
Seror, Oliver. "Adaptation et évaluation du monitorage par IRM de température des ablations hépatiques par radiofréquence." Bordeaux 2, 2006. http://www.theses.fr/2006BOR21331.
In this work the feasibility and the accuracy of MR-thermometry based on the proton resonance frequency shift and using the concept of thermal dose for the monitoring of radiofrequency ablation in the liver were assed. Before the achievement of a clinical pilot study, we carried out three experimental studies : the first was performed ex vivo on liver samples, the second in vivo in the liver of rabbits and the third in vivo in the liver of pigs using clinical available radiofrequency material. Finally the clinical study consisted of the treatment of malignant liver tumours of eight patients by radiofrequency ablation under continuous MR-thermometry monitoring. At each steps of this work Mr-thermometry appeared as a faeasible and reliable monitoring technique to assess in real time the extent of ablation zone during radiofrequency ablation. Further changes in imaging protocol and in the radiofrequency material might improve significantly the effectiveness of this new monitoring imaging
Côté, Jérôme. "Caractérisation d'analogues des kinines comme agents perméabilisant la barrière hémato-encéphalique dans un modèle expérimental de cancer du cerveau." Thèse, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6228.
Viard, Romain. "L'Imagerie Interventionnelle par Résonance Magnétique: Application en thermothérapie laser interstitielle pour le traitement des tumeurs hépatiques." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2007. http://tel.archives-ouvertes.fr/tel-00192916.
L'objectif de cette thèse, qui bénéficie du soutien de la Région Nord Pas de Calais et du CHRU de Lille de 2005 à 2007, est de fournir des outils pour l'assistance par IRM de la thermo-ablation par laser. Les différents développements offriront ainsi non seulement un outil de préparation à cet acte complexe (visualisation en trois dimensions des tumeurs du patient, calcul de la trajectoire optimale pour éviter la perforation de structures anatomiques vitales ...) mais également des outils d'assistance per-opératoire (positionnement du guide assisté par la stéréovision sur les premiers centimètres, évaluation des dommages thermiques de la zone traitée...).
Lors de cette première phase, nous nous sommes concentrés sur les tumeurs hépatiques, qui demeurent une réelle difficulté, tout en proposant un système pouvant être adapté à toute tumeur abdominale.
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.
Prostate 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
Gardet, Yves. "Intérêt du scanner et de l'imagerie par résonance magnétique dans le bilan pré-opératoire des cancers de la partie basse du rectum : à propos de 19 cas opérés au C.R.L.C. de Montpellier." Montpellier 1, 1989. http://www.theses.fr/1989MON11113.
Cavailles, Matthieu. "Design innovant de matrices polarisantes pour le diagnostic précoce du cancer par IRM." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1204/document.
The goal of this PhD project was to develop a new methodology allowing to immobilize paramagnetic species on mesoporous silica in order to optimize the dynamic nuclear polarization process. For this purpose, different polarizing matrices, denoted as HYPSO for “HYbrid Polarizing SOlids”, were prepared through a sol-gel process. These solids are highly porous and paramagnetic species are covalently attached onto the surface. One of the noticeable benefit of this method lies in the possibility to remove the “glass forming agent” because of a homogeneous and random repartition of the radicals onto the surface of these materials. Two types of polarizing matrices, HYPSO 2 and HYPSO 3 gave distinct polarizations: P(1H)= 50% and P(1H)= 63%. This difference was explained by the influence of the silica matrix which provides better performances when its porosity is interconnected in the 3 dimensions of the space. Following these results, new materials (HYPSO 5) were prepared. The influence of the pore sizes as well as those of the silica grains on the polarization were studied. Remarkable performances: P(1H)= 99% (± 5%) et P(13C)= 51 % were recorded, thereby demonstrating the efficiency of this new method. Moreover, the first MRI pictures using HYPSO 5 as polarizing matrices were obtained after hyperpolarization of a sodium acetate solution. Finally, we were interested to a new formulation based on silica xerogels. Preliminaries results showed good polarizations and the ability to use only one monolith to polarize different liquids
Ouldamer, Lobna. "Evaluation de la spectroscopie par résonance magnétique du tissu adipeux mammaire comme marqueur non invasif de la part nutritionnelle du cancer du sein." Thesis, Tours, 2016. http://www.theses.fr/2016TOUR3304.
Fatty acid composition of the white adipose tissue remains the most reliable qualitative biomarker of previous dietary intake of fatty acids and may provide information on the nutritional part of the risk or evolution of breast cancer. This opens the prospect of individualization of women at high nutritional risk of breast cancer that may benefit from a targeted nutritional intervention but 1) the need for biopsy and 2) subsequent time-consuming biochemical analyses hamper any application of this approach. Proton magnetic resonance spectroscopy (1H-MRS) of adipose tissue lipids represents an appealing, non-invasive approach, which could circumvent these limitations. This manuscript reports: 1) an assessment of feasibility of (1H-MRS) to evaluate the consequences of a nutritional intervention in a rat mammary tumor model on the adipose tissue fatty acid composition, 2) an assessment of the feasibility of in vivo measurement of the fatty acid composition of breast adipose tissue by (1H-MRS) on a clinical platform, 3) an assessment of the relation of specific patterns of composition of adipose tissue fatty acids with the presentation of breast cancer, and 4) a comparison with gas chromatography of (1H-MRS) data acquired on breast adipose tissue in vitro (11.7T) and in vivo (3T) on patients managed for breast cancer
Lemay, Rosalie. "Prévention de l'augmentation de l'invasion des cellules cancéreuses du sein induite par les radiations avec un inhibiteur de COX-2." Thèse, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/8192.
Abstract: Most women with early breast cancer are treated with radiotherapy to the whole breast. Despite the efficiency of this treatment, the dose of radiation is not calculated to eliminate all the residual cancer cells, but rather to obtain the best long-term results with minimal side-effects. The observed side-effects all result from inflammatory processes caused by radiation. Increase of inflammatory molecules expression and activity, such as cyclooxygenase-2, in normal and malignant tissues induce invasion and tumour angiogenesis. Both of these important mechanisms lead to metastasis formation. The general aim of this research project is to improve radiotherapy by decreasing breast cancer recurrence. Specific objectives were to determine with magnetic resonance imaging that irradiation of normal tissues could increase breast cancer cells invasiveness in vivo, stimulate tumour neovascularization and prevent radiation-enhanced invasion by the administration of an anti-inflammatory agent inhibiting selectively the cyclooxygenase-2 during radiotherapy. In this study, we have developed a new assay to monitor angiogenesis in Matrigel plugs in live mice using magnetic resonance imaging. This method would be a promising tool to test the effect of radiation on tumour angiogenesis. We also followed in a mouse model the invasion of mammary cancer cells implanted post-irradiation of healthy tissues. We demonstrated that irradiation of healthy tissues leads to an increase in mammary cancer cells invasion. Radiation-induced invasion was observed with a unique 30 Gy dose as well as with a more clinically-relevant fractionated protocol consisting in 5 irradiations of 7.5 Gy. Then, mice were treated with NS-398, a selective inhibitor of cyclooxygenase-2. NS-398 limits the increase of invasion stimulated by radiation. These results could support new treatments development based on COX-2 inhibition to increase radiotherapy efficiency for women with breast cancer.
Joffre, Philippe. "Apport comparé de l'imagerie par résonance magnétique et de la tomodensitométrie dans le bilan pré-thérapeutique et le suivi des cancers du larynx et du sinus piriforme : à propos e 42 cas." Montpellier 1, 1988. http://www.theses.fr/1988MON11210.
Pasquier, David. "Imagerie par Résonance Magnétique et radiothérapie conformationnelle: Caractérisation de l' Imagerie par Résonance Magnétique pour son utilisation dans l' établissement des plans de traitement en radiothérapie conformationnelle. Développement et évaluation d'un outil de délinéation automatique et semi- automatique des volumes d'intérêt pour la radiothérapie conformationnelle du cancer prostatique." Phd thesis, Université du Droit et de la Santé - Lille II, 2006. http://tel.archives-ouvertes.fr/tel-00483654.
Granier, Bettina. "Chondromes et chondrosarcomes : apports de l'imagerie moderne." Montpellier 1, 1991. http://www.theses.fr/1991MON11101.
Laharie, David. "Diagnostic d'un nodule hépatique sur cirrhose : imagerie par résonance magnétique nucléaire ou tomodensitométrie hélicoi͏̈dale? Etude de 87 nodules chez 34 malades transplantés." Bordeaux 2, 1999. http://www.theses.fr/1999BOR23063.
Niaf, Émilie. "Aide au diagnostic du cancer de la prostate par IRM multi-paramétrique : une approche par classification supervisée." Electronic Thesis or Diss., Lyon 1, 2012. http://www.theses.fr/2012LYO10271.
Prostate cancer is one of the leading cause of death in France. Multi-parametric MRI is considered the most promising technique for cancer visualisation, opening the way to focal treatments as an alternative to prostatectomy. Nevertheless, its interpretation remains difficult and subject to inter- and intra-observer variability, which motivates the development of expert systems to assist radiologists in making their diagnosis. We propose an original computer-aided diagnosis system returning a malignancy score to any suspicious region outlined on MR images, which can be used as a second view by radiologists. The CAD performances are evaluated based on a clinical database of 30 patients, exhaustively and reliably annotated thanks to the histological ground truth obtained via prostatectomy. Finally, we demonstrate the influence of this system in clinical condition based on a ROC analysis involving 12 radiologists, and show a significant increase of diagnostic accuracy, rating confidence and a decrease in inter-expert variability. Building an anatomo-radiological correlation database is a complex and fastidious task, so that numerous studies base their evaluation analysis on the expertise of one experienced radiologist, which is thus doomed to contain uncertainties. We propose a new classification scheme, based on the support vector machine (SVM) algorithm, which is able to account for uncertain data during the learning step. The results obtained, both on toy examples and on our clinical database, demonstrate the potential of this new approach that can be extended to any machine learning problem relying on a probabilitic labelled dataset
Ramgolam, Anoop. "Conception, caractérisation et validation d'une sonde endoluminale bimodale couplant l'imagerie par résonance magnétique et la spectroscopie optique en vue du diagnostic du cancer colorectal." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10105.
The main aim of this work is the development of a new diagnostic technique combining high spatial resolution MRI to autofluorescence and reflectance spectroscopy through the conception of a bimodal endoluminal probe. Such a technique falls within the framework of alternative innovative techniques to conventional colonoscopy that would allow better sensitivity to early stage digestive pathologies. Colorectal cancer is today a major health issue worldwide with more than 1.2 million cases diagnosed each year bearing the fact that the 5 year survival rate is 94% when precancerous lesions are diagnosed at an early stage (stage I) and only 8% when diagnosed at an advanced stage (stage IV). The promising imaging and spectral analysis techniques under investigation or undergoing clinical evaluation in different parts of the world are presented in the first chapter of this manuscript along with the basic physics involved in magnetic resonance imaging and optical spectroscopy. Chapter 2 gives a detailed description of the work carried out in devising and conceiving different endoluminal bimodal probe prototypes along with the dedicated optical test benches. Dedicated data processing and visualisation programmes developed are also presented within this chapter. The final chapter of this work deals with the different studies carried out in-vitro on different phantoms and in-vivo on a rabbit. Morphological information obtained through the MR images are also correlated to the biochemical information through the autofluorescence and reflectance spectra
Besson, Florent. "Integrating PET-MR data for a multiparametric approach of tumour heterogeneity in non-small-cell lung cancer (NSCLC)." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS081.
Tumor heterogeneity is an important factor of progression and resistance to treatment. Multiparametric PET-MRI imaging offers unique opportunities to characterize biological cellular processes, but has never been evaluated at the regional level in Non-Small Cell Lung Cancer (NSCLC), the leading cause of oncological death. A simultaneous dynamic multiparametric 18F-FDG PET-MRI approach has been developed to this end. This approach required the “in-house” implementation of the reference absolute PET quantitative method of glucose metabolism (Sokoloff's tri-compartmental model); the development of a method for correcting geometric distortions in diffusion weighted imaging, validated on phantom and clinically tested; the phantom validation of quantitative MRI methods (T1/T2 relaxometry), also clinically tested; and the "in-house" implementation of the Tofts compartmental model (extended version) for the evaluation of tumor vascularization by dynamic perfusion MRI. The results of our work, performed at the regional intra-tumor level, illustrate the heterogeneity of the regional interlinks between glucose metabolism and vascularization in NSCLC, two fundamental biological hallmarks of tumor progression, and show that an unsupervised tumor partitioning by Gaussian mixture model, integrating all the PET-MRI biomarkers of this project, individualizes 3 types of supervoxels, whose biological signature can be predicted with 97% accuracy by 4 dominant PET-MRI biomarkers, revealed by metaheuristic machine learning methods
Marie, Hélène. "Magnétoliposomes pour le diagnostic et le traitement du glioblastome par vectorisation magnétique et hyperthermie." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA114834.
First, the in vivo study on U87-glioblastoma bearing mice demonstrates the ability of magnetic targeting to accumulate magnetic-fluid-loaded liposomes (MFLs) into glioblastoma while sparing the rest of the healthy brain tissue. The enhancement of liposome local concentration by applying a magnetic field gradient produced by an external magnet is based on an amplified EPR effect (“enhanced permeation and retention” effect). The results were supported by combining several techniques (MRI, ESR, confocal fluorescence microscopy, electron microscopy). The investigations concerning the mechanisms of transport of the magnetoliposomes to reach the tumor cells suggest a non-specific endocytose pathway, presumably macropinocytosis. Secondly, in the context of a therapeutic application by hyperthermia the heat capacity of MFLs was explored. The results showed that the thermal behaviour of the magnetoliposomes depends on the containment state of the iron oxide nanocrystals and is compatible with the conditions of hyperthermia treatment. Finally, as part of a study concerning the development of mechanically induced cancers, application of MFLs was extended to target another organ not yet studied: the colon. This work especially illustrates the potential and related limits of magnetic targeting towards an organ located in an inner region of the body
Niaf, Émilie. "Aide au diagnostic du cancer de la prostate par IRM multi-paramétrique : une approche par classification supervisée." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10271/document.
Prostate cancer is one of the leading cause of death in France. Multi-parametric MRI is considered the most promising technique for cancer visualisation, opening the way to focal treatments as an alternative to prostatectomy. Nevertheless, its interpretation remains difficult and subject to inter- and intra-observer variability, which motivates the development of expert systems to assist radiologists in making their diagnosis. We propose an original computer-aided diagnosis system returning a malignancy score to any suspicious region outlined on MR images, which can be used as a second view by radiologists. The CAD performances are evaluated based on a clinical database of 30 patients, exhaustively and reliably annotated thanks to the histological ground truth obtained via prostatectomy. Finally, we demonstrate the influence of this system in clinical condition based on a ROC analysis involving 12 radiologists, and show a significant increase of diagnostic accuracy, rating confidence and a decrease in inter-expert variability. Building an anatomo-radiological correlation database is a complex and fastidious task, so that numerous studies base their evaluation analysis on the expertise of one experienced radiologist, which is thus doomed to contain uncertainties. We propose a new classification scheme, based on the support vector machine (SVM) algorithm, which is able to account for uncertain data during the learning step. The results obtained, both on toy examples and on our clinical database, demonstrate the potential of this new approach that can be extended to any machine learning problem relying on a probabilitic labelled dataset
Ouzzane, Adil. "Diagnostic du cancer de la prostate par imagerie moderne : place de l’IRM dans la sélection des candidats à une surveillance active et dans la caractérisation des zones tumorales intra-prostatiques." Thesis, Lille 2, 2014. http://www.theses.fr/2014LIL2S054/document.
MRI is an increasingly important imaging modality for prostate cancer diagnosis. Further indications are being validated in prostate cancer to establish the prognostic, to guide treatment and to follow up patients especially after partial treatment. The first part of this work has focused on clinical studies of MRI in patient selection for active surveillance. The performance of MRI particularly in the detection of anterior cancers would reduce the risk of initial underestimation of tumor burden and therefore reduce the risk of reclassification during active surveillance protocols. The second part of this work has focused on the correlation between the signal abnormalities on MRI and intra-prostatic areas. We used a simple and reproducible technique for MRI and histopathology registration and we correlated signal abnormalities recorded on MRI with quantitative histopathological parameters at prostatectomy surgical specimens
Li, Xiaobing. "Automatic image segmentation based on level set approach: application to brain tumor segmentation in MR images." Reims, 2009. http://theses.univ-reims.fr/exl-doc/GED00001120.pdf.
The aim of this dissertation is to develop an automatic segmentation of brain tumors from MRI volume based on the technique of "level sets". The term "automatic" uses the fact that the normal brain is symmetrical and the localization of asymmetrical regions permits to estimate the initial contour of the tumor. The first step is preprocessing, which is to correct the intensity inhomogeneity of volume MRI and spatially realign the MRI volumes of the same patient at different moments. The plan hemispherical brain is then calculated by maximizing the degree of similarity between the half of the volume and his reflexion. The initial contour of the tumor can be extracted from the asymmetry between the two hemispheres. This initial contour is evolved and refined by the technique "level set" in order to find the real contour of the tumor. The criteria for stopping the evolution have been proposed and based on the properties of the tumor. Finally, the contour of the tumor is projected onto the adjacent images to form the new initial contours. This process is iterated on all slices to obtain the segmentation of the tumor in 3D. The proposed system is used to follow up patients throughout the medical treatment period, with examinations every four months, allowing the physician to monitor the state of development of the tumor and evaluate the effectiveness of the therapy. The method was quantitatively evaluated by comparison with manual tracings experts. Good results are obtained on real MRI images
Epaule, Céline. "Nouvelle approche d'imagerie pour l’étude de la biodistribution de nanomédicaments." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS435.
Nowadays, the in vivo distribution of drugs is studied by non-spatial or partially spatial quantitative techniques. With the development of personalized therapies, many studies are required to know the in vivo behaviour of these innovative treatments, which target drugs, such as nanoparticles (NPs). Into the European funded program Ternanomed, the aim of this multidisciplinary research project was to evaluate two complementary imaging methods to study the distribution of squalene and Cis platinum (Cis Pt) NPs. The 2 imaging methods were selected to provide complementary data at the scale of organs and tissues: i) Magnetic resonance imaging (MRI) to monitor the in vivo biodistribution of NPs models based on Cis-Pt and BiSqualene (BiSQ), labelled with "UltraSmall Iron Oxide Particle" (USPIO) contrast agents, ii) X-ray microfluorescence imaging, coupled with synchrotron radiation (SR-μXRF) without any labelling of these nanomedicines, by following the Cis-Pt drug distribution into tissues.Regarding the MRI approach, we first successfully prepared Cis-Pt BiSQ NPs loading with USPIO (210nm, polydispersity 0,1). These NPs were given a contrast at 7 Tesla (r2 = 404 ms.mol-1 and r1 = 3 ms.mol-1). These newly prepared and characterized NPs were also trackable into our Nude murine model. The results show a rapid arrival of contrast in the liver and spleen scavengers (5 minutes after injection). Ultimately, MRI analysis yielded real-time biodistribution data for Cis-Pt BiSQ-based NPs by monitoring the contrast provided by encapsulated USPIO. Regarding the SR-μXRF imaging analysis, we demonstrated that this technique is very sensitive to detect and map the Cis-Pt distribution, the drug vectorized by our squalene NPs models. Additionally, a local quantitative analysis is feasible when a microelement present in the tissue is used as a reference, in our study the Zinc element. The distribution of Cis-Pt was quantified in the hepatic, renal and fat tissues, after 2h and 24h, with our method validated by the global Platinum microanalyse using atomic absorption spectrometry. When the tissue reference appears not homogenously distributed, a semi-quantitative analysis method is possible to compare the distribution such as into PANC-1 tumour sections.Finally, these two complementary approaches illustrate the use of SR-μXRF and lay the optimized bases of MRI to study the pharmacokinetics and pharmacodynamics of two new types of Cis-Pt/squalene NPs. The SR-μXRF technique, newly used in pharmaceutical field, had an effective contribution to these original and pioneering research studies with an original way of in vivo assessment of the distribution of drug embedded into nanomedicine system. The issue of detecting correct and measurable distribution of the drugs is extremely important, timely and relevant to improve current knowledge in the state of the art. This research study brings new data which can produce significant impact to the overall area of nanomedicine
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.
Prostate 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
Maggiori, Léon. "Métastases hépatiques infra-cliniques de cancer colorectal : modélisation et applications diagnostiques et thérapeutiques." Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCC294.
Live is the most frequent metastatic site of colorectal cancer. Lver is the oniy involved Metastatic site in 80% of the patients. Nowadays, compklete surgical resection is the gold standard treatment of liver metastasis (LM). However, this resection is initially only possible in 30% of the patients. Several techniques have been described to enhance the future remnant liver volume after LM resection, such as portal embolization and portal ligation. Furthermore, the recurrence rate following complete resection of LM is up to 30% of patients, suggesting the potentially of "infra-clinical" LM, not detected during preoperative work-up. We developed a safe and reproducible experimental model of such infra-clinicat LM in the immunocompetent rat. We also developed experimental models of portal embolization and ligation, allowing to assess the impact of the techniques on LM natural history. These experimental models allowed us to show a significant impact of the portal occlusion techniques on LM natural history: portal embolization increased LM growth in the occluded liver white portal ligation decreased this growth. Finally, we showed that diffusion weighted magnetic resonance imaging was associated to higher detection performances than standard imaging, for infra-ciinical LM
Trillet-Lenoir, Véronique. "Identification de facteurs pronostiques au cours du cancer bronchique indifférencié à petites cellules." Lyon 1, 1991. http://www.theses.fr/1991LYO1H076.
Tomi-Tricot, Raphaël. "Clinical applications of the kT-points method to homogenise spin excitation in 3T MRI." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS260/document.
High field magnetic resonance imaging (MRI) is often used in clinical practice, for the high signal-to-noise ratio it offers.However, at high field, the radiofrequency (RF) wavelength used for imaging is shorter, which can induce loss of signal and contrast when it is close to or shorter than the dimensions of the irradiated objects. At 3T, RF wavelength is about 30 cm in human tissues,and such artefacts are frequently observed in the abdomen, as well as in the thighs or in the breasts. This is certainly one of the main reasons why high field MRI has failed to establish itself as the gold standard in hospital, where 1.5T scanners are more frequent.Recent 3T scanners usually come with a two-RF-channel parallel transmission setup: in principle, each channel can transmit completely independent waveforms. However, this technology is not exploited fully in practice, as only the static RF shimming is implemented: a single waveform is used, with adjusted amplitude and phase on each channel. This allows to create interference patterns, calculated to counteract transmission inhomogeneities measured beforehand in the patient (RF and possibly static field).This method works best when many channels are available, but shows its limits when good homogeneity is expected over a large field of view. The kT-points method, developed at CEA-NeuroSpin for brain imaging at ultra-high field (7T) relies on a succession of short rectangular RF pulses interleaved with static gradient “blips” to modulate magnetisation at will, thus producing homogeneous excitation in spite of an imperfect RF field. Those composite pulses are even more effective as they can take advantage of parallel transmission (eight channels at 7T). In this thesis, the kT-points technique is applied at 3T. The objective is to demonstrate its usefulness and its compatibility with a clinical routine workflow. First, several changes made to the kT-points pulse design algorithm and to static field mapping in order to adapt them to body imaging (liver, breasts) are described. Indeed, the presence of lungs and fat add further constraints compared to the brain. Then, several clinical studies are detailed. The first one regards T₂-weighted breast MRI on a single-channel scanner. It shows that in that case the default transmit mode is satisfactory,and only slightly improved by kT-points. A second study focuses on T₁-weighted dynamic contrast-enhanced imaging of the liver,with two transmit channels. Static RF shimming and kT-points were compared on a large cohort. For some “difficult” patients,acquisitions were quantitatively and qualitatively better with kTpoints,which therefore offer a more uniform diagnostic quality among the population. Finally, a novel method is proposed:SmartPulse. It is based on the universal pulse concept, developed in NeuroSpin for brain imaging, whose principle is to design pulses (e.g. kT-points) for a given application, that homogenise excitation in the whole population, and not only for one subject.Thus, there is no more need for cumbersome mapping and inline pulse design. SmartPulse extends the range of universal pulses to body imaging, by adequately clustering the population, designing different pulses for each cluster, and applying a machine learning classifier to assign the most appropriate pulse to any new subject.Proof of concept was undertaken in abdominal imaging, whereinter-subject variability is considerable. We hope this thesis will give a new outlook on RF inhomogeneity handling in routine 3T MRI, and in the long run will help making body imaging moreaccessible at high and ultra-high field