Tesis sobre el tema "Imagerie par ultrasons en 3D"
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Tamraoui, Mohamed. "Sparse array 3D ultrasound imaging". Electronic Thesis or Diss., Lyon 1, 2024. https://theses.hal.science/tel-04828515.
Texto completoSparse arrays present several notable advantages over other element reduction techniques for 3D ultrasound imaging. One of the most promising benefits is their ability to freely steer the ultrasound beam in all directions, which significantly enlarges the field of view. This capability opens up possibilities for implementing advanced imaging sequences, such as diverging waves, which are particularly beneficial for applications like echocardiography. Additionally, sparse arrays use fewer elements, reducing the complexity and cost of manufacturing and operating the transducer arrays. This reduction in hardware can also simplify the system design and decrease power consumption. Despite their advantages, sparse arrays face two significant challenges: low sensitivity and reduced image contrast. The primary objectives of this thesis are twofold: first, to increase the signal-to-noise ratio (SNR) of sparse arrays; second, to enhance image contrast. This research is part of the ANR (Agence National de la Recherche) Project named SPARse array TECHniques FOR 3D medical UltraSound (SPARTECHUS). SPARTECHUS is a collaborative project between our laboratory, CREATIS, and Imasonic, an ultrasound transducer manufacturer, with the aim of developing the next generation of ultrasound arrays 3D ultrasound imaging. By hypothesizing that transducer elements with higher sensitivity and equivalent directivity can be developed, Imasonic focused on developing a new prototype of a sparse array. My contribution consisted of combining their technology with coded excitation sequences, with the goal of improving the SNR. Then, to address the problem of poor image contrast due to high sidelobe levels, I developed a new reconstruction algorithm based on deep learning networks, specifically trained for the new prototype probe. This algorithm will focus on optimizing the beamforming processes to achieve high-quality ultrasound images. Together, these objectives aim to overcome the principal challenges associated with sparse probes, paving the way for their more effective use in 3D ultrasound imaging
Finel, Victor. "3D ultrafast echocardiography : toward a quantitative imaging of the myocardium". Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC134/document.
Texto completoThe objectives of this PhD thesis were to develop 3D ultrafast ultrasound imaging of the human heart toward the characterization of cardiac tissues. In order to do so, a customized, programmable, ultrafast scanner built in our group was used. In the first part of this thesis, a real-time imaging sequence was developed to facilitate in-vivo imaging using this scanner, as well as dedicated 3D and 4D visualization tools. Then, we developed 3D Backscatter Tensor Imaging (BTI), a technique to visualize the muscular fibres orientation within the heart wall non-invasively during the cardiac cycle. Applications on a healthy volunteer before and after cardiac contraction was shown. Moreover, the undesired effects of axial motion on BTI were studied, and a methodology to estimate motion velocity and reduce the undesired affects was introduced and applied on a healthy volunteer. This technique may become an interesting tool for the diagnosis and quantification of fibres disarrays in hypertrophic cardiomyopathies. Moreover, 3D ultrafast ultrasound was used to image the propagation of naturally generated shear waves in the heart walls, and an algorithm to determine their speed was developed. The technique was validated in silico and the in vivo feasibility was shown on two healthy volunteers, during cardiac contraction and relaxation. As the velocity of shear waves is directly related to the rigidity of the heart, this technique could be a way to assess the ability of the ventricle to contract and relax, which is an important parameter for cardiac function evaluation. Finally, the transient myocardial contraction was imaged in 3D on isolated rat hearts at high framerate in order to analyse the contraction sequence. Mechanical activation delays were successfully quantified during natural rhythm, pacing and hypothermia. Then, the feasibility of the technique in 2D on human hearts non-invasively was investigated. Applications on foetuses and adults hearts were shown. This imaging technique may help the characterization of cardiac arrhythmias and thus improve their treatment. In conclusion, we have introduced in this work three novel 3D ultrafast imaging modalities for the quantification of structural and functional myocardial properties. 3D ultrafast imaging may become an important non-ionizing, transportable diagnostic tool that may improve the patient care at the bed side
Follet, Hélène. "Caractérisation biomécanique et modélisation 3D par imagerie X et IRM haute résolution de l'os spongieux humain : évaluation du risque fracturaire". Lyon, INSA, 2002. http://theses.insa-lyon.fr/publication/2002ISAL0105/these.pdf.
Texto completoTo prevent bone pathology, the aim of this study is to test a new methodology to evaluate fracture risk of human calcaneus cancellous bone. By using i) clinical data (bone mineral density, microstructure, DXA, Scanner X, Histomorphometry) and ii) high definition imaging techniques (RMN at 78 µm and µComputed Tomography at 10µm), it will be possible to estimate cancellous bone mechanical properties (Young Modulus and compressive maximal stress). Two tests have been implemented : a compressive test on a cubic sample of cancellous bone, and secondly, a bending test on trabecular bone. Different finite element models of these have been used and allow to determine mechanical properties of trabecular bone. Fracture risk can be evaluated by damage quantification and tissue strain level. Results of this methodology will then be compared with those obtained by classical clinical techniques
Follet, Hélène Rumelhart Claude. "Caractérisation biomécanique et modélisation 3D par imagerie X et IRM haute résolution de l'os spongieux humain évaluation du risque fracturaire /". Villeurbanne : Doc'INSA, 2006. http://docinsa.insa-lyon.fr/these/pont.php?id=follet.
Texto completoRobin, Justine. "Development of a 3D time reversal cavity for pulsed cavitational ultrasound : application to non-invasive cardiac therapy". Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC273/document.
Texto completoThe objective of this thesis was to explore new applications for cardiac histotripsy, and to develop the tools making it possible non-invasively. Cardiac ultrasound therapy indeed still remains limited due to the tremendous challenge of treating a constantly and rapidly moving organ, well protected behind the ribcage.We first showed in vivo, on a large animal model, that histotripsy could be used non-invasively to cut mitral chordae, and to treat calcified aortic stenosis in a beating heart. Cavitation on the valve leaflets can indeed locally and remotely act on the calcifications, and globally soften the valve. Simultaneously, we developed a therapeutic device allowing completely non-invasive cardiac shock-wave therapy based on the time reversal cavity concept. In particular, this device allows the emission of high intensity ultrasound pulses, and provides 3D electronical steering of the therapy focal spot in a large volume. After a thorough optimisation process, this device was capable of creating well controlled mechanical lesions over a 2 000 cm3 region of interest. To tackle the challenge of ultrasound propagation through the rib cage, we developed an adaptive focusing method (DORT method through a time reversal cavity), and implemented it in a 2D prototype of the device. With this method, we not only could build an adaptive ultrasonic wavefront propagating preferentially through the intercostal spaces, but due to time reversal cavities properties, we could also increase the peak pressure obtained on target.Finally, we pushed our work on adaptive focusing further, and considered the case of transcranial imaging. For this application, we chose to use the time reversal of speckle noise technique, to correct the aberrations induced by the skull. In numerical simulations, we were able to derive the phase and amplitude modulations induced by the bones, and could improve the contrast and resolution of a B-mode image
Sauvage, Jack. "Imagerie ultrasonore ultrarapide 4D par adressage orthogonal du réseau de sonde matricielle : adressage Ligne-Colonne". Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS535.
Texto completoWith the advent of 4D ultrafast imaging at the Physics for Medicine Inserm 1273 laboratory, the ability to acquire in all three dimensions and with a high spatio-temporal resolution has been demonstrated. Several of the most effective 2D ultrafast imaging modalities have been extended to volume imaging (3D ultrasensitive power Doppler, 3D elastography ...). Their dissemination in clinic would greatly benefit to physicians. However the necessary means to implement ultrafast 4D are still too heavy and costly to hope for a transposition in the short or mid-term to the radiology departments. Developing smart strategies to reduce channel number has become a central issue. An original strategy based on the probe architecture consists of orthogonal row and column addressing of the Matrix Probe array, the Row and Column Adressing RCA. It offers a transducer solution perfectly adapted with ultra-fast plane waves imaging. With this approach, the probe can be driven by a single standard ultrasound unit, while maintaining a large aperture. The 2D matrix grid is organized according to N + N orthogonal channels, thus representing a reduction factor of N / 2. This strategy presents an important paradigm shift of imaging by dissociation of the focus pathways in transmission and reception and offers a new compromise in terms of spatio-temporal resolution. During this thesis work, the performances of the RCA associated with the ultra fast 4D imaging are studied for various cases. The principle of 4D ultrafast RCA imaging with orthogonal summation OPW are studied. 3D vector imagery for RCA is developed. A new high frequency RCA probe prototype (15MHz) is presented and tested on a 3D functional brain imaging protocol. Finally, a new modality of 3D imaging of the flux intensity is presented offering a new way of exploitation for the RCA probe
Lorintiu, Oana. "Reconstruction par acquisition compressée en imagerie ultrasonore médicale 3D et Doppler". Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0093/document.
Texto completoThis thesis is dedicated to the application of the novel compressed sensing theory to the acquisition and reconstruction of 3D US images and Doppler signals. In 3D US imaging, one of the major difficulties concerns the number of RF lines that has to be acquired to cover the complete volume. The acquisition of each line takes an incompressible time due to the finite velocity of the ultrasound wave. One possible solution for increasing the frame rate consists in reducing the acquisition time by skipping some RF lines. The reconstruction of the missing information in post processing is then a typical application of compressed sensing. Another excellent candidate for this theory is the Doppler duplex imaging that implies alternating two modes of emission, one for B-mode imaging and the other for flow estimation. Regarding 3D imaging, we propose a compressed sensing framework using learned overcomplete dictionaries. Such dictionaries allow for much sparser representations of the signals since they are optimized for a particular class of images such as US images.We also focus on the measurement sensing setup and propose a line-wise sampling of entire RF lines which allows to decrease the amount of data and is feasible in a relatively simple setting of the 3D US equipment. The algorithm was validated on 3D simulated and experimental data. For the Doppler application, we proposed a CS based framework for randomly interleaving Doppler and US emissions. The proposed method reconstructs the Doppler signal using a block sparse Bayesian learning algorithm that exploits the correlation structure within a signal and has the ability of recovering partially sparse signals as long as they are correlated. This method is validated on simulated and experimental Doppler data
Follet, Hélène. "Caractérisation Biomécanique et Modélisation 3D par Imagerie X et IRM haute résolution de l'os spongieux humain : Evaluation du risque fracturaire". Phd thesis, INSA de Lyon, 2002. http://tel.archives-ouvertes.fr/tel-00003145.
Texto completoSivadon, Audrey. "Contributions à l’imagerie passive de la cavitation ultrasonore : formation de voies adaptatives en 3D et extension spatiale de nuages de bulles". Electronic Thesis or Diss., Lyon 1, 2022. http://www.theses.fr/2022LYO10172.
Texto completoPassive imaging relies on beamforming algorithms that require large aperture probes to provide good axial resolutions; however, in 3D passive imaging, the matrix probes currently marketed do not meet this constraint. Moreover, these probes have a large number of elements, which makes their use particularly unwieldy. This thesis work focuses on the study and improvement of passive cavitation imaging by addressing two aspects in particular: (i) the practical and efficient implementation of 3D passive imaging, (ii) the problem of imaging large sources such as cavitation clouds. We have combined the application of sparse methods (to reduce the number of active elements of the probe used) and the transposition from 2D to 3D of adaptive algorithms in the frequency domain. This formalism uses the robust estimation of the inter-spectral density matrix (CSM) and allowed us to implement simply and efficiently different algorithms: Delay-And-Sum (DAS), Robust-Capon-Beamformer and Pisarenko. The efficiency of these algorithms in 3D has been tested in terms of width to half height, contrast and position error, on a point source in simulations and on a point reflector in experiments. Finally, in order to address the reality of cavitation clouds, we have investigated the behavior of these reconstruction methods in the case of extended sources. Our 2D simulations show the evolution of the reconstructed images as a function of the cavitation cloud characteristics. This work provides a concrete solution for a simple implementation of 3D passive imaging as well as answers to the expectations on the localization and characterization of a cavitation cloud
Daunizeau, Loïc. "Développement de la thérapie ultrasonore conformationnelle par voie interstitielle pour le traitement du carcinome hépatocellulaire". Electronic Thesis or Diss., Lyon, 2020. http://www.theses.fr/2020LYSE1326.
Texto completoHepatocellular carcinoma is the most common primary cancer of the liver. Interstitial thermal ablation procedures constitute a type of curative treatments for this cancer. Given the physical nature of the phenomenon used to modify temperature (radio frequency, micro wave, laser, cryotherapy), those methods may not be able to generate a conformal treatment for a given tumor shape. In some cases, this limitation may induce the thermal ablation of a large volume of non-tumor tissues. The use of an ultrasound interstitial probe mounted with a multi-element transducer capable of generating high intensity focused ultrasound (HIFU) may theoretically help to overcome this limitation. Also a transducer with an important number of elements may also provide in situ imaging. As a first step, the design of a transducer for interstitial ultrasound probe was studied. A specific configuration has been proposed for the treatment of tumors with a diameter of 4 cm. The question of the treatment planning method to adopt to reach an optimal conformal treatment has been then addressed by comparing numerical simulations of different strategies. All strategies were sufficiently conformal and none presented real assets compared to the others. Ultrasound focusing in itself provided the desired conformal thermal ablation. Finally, a robotic platform was developed for driving interstitial dual mode ultrasound probes, both in imaging and in therapy mode. This platform allowed the automatic treatment planning of in vitro tumor mimic phantoms, based on 3D ultrasound reconstruction from the B mode images obtained in situ by the interstitial probe. However, in therapy mode, the probes did not reach their specifications and did not manage to create thermal lesions in in vitro liver tissue sample. The modularity of the robotic platform allowed driving a different HIFU system, which was more robust. With this system, the platform managed to perform with success an automatic treatment planning and then the associated HIFU treatment in in vitro tissue sample
Salles, Sébastien. "Estimation du mouvement de la paroi carotidienne en imagerie ultrasonore par une approche de marquage ultrasonore". Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0092/document.
Texto completoThis work focuses on the processing of biomedical images. The aim of our study is to estimate the mechanical properties of the carotid artery in vivo using ultrasound imaging, in order to detect cardiovascular diseases at an early stage. Over the last decade, researchers have shown interest in studying artery wall motion, especially the motion of the carotid intima-media complex in order to demonstrate its significance as a marker of Atherosclerosis. However, despite recent progress, motion estimation of the carotid wall is still difficult, particularly in the longitudinal direction (direction parallel to the probe). The development of an innovative method for studying the movement of the carotid artery wall is the main motivation of this thesis. The three main contributions proposed in this work are i) the development, the validation, and the clinical evaluation of a novel method for 2D motion estimation of the carotid wall, ii) the development, the simulation and the experimental validation of the 3D extension of the estimation method proposed, and iii) the experimental evaluation of the 2D proposed method in ultra-fast imaging, for the estimation of the local pulse wave velocity. We propose a motion estimation method combining tagging of the ultrasound images, and a motion estimator based on the phase of the ultrasound images. The ultrasonic tagging is produced by means of transverse oscillations. We present two different approaches to introduce these transverses oscillations, a classic approach using a specific apodization function and a new approach based on filtering. The proposed motion estimator uses the 2D analytical phase of RF images using the Hahn approach. This thesis work shows that, compared with conventional methods, the proposed approach provides more accurate motion estimation in the longitudinal direction, and more generally in directions perpendicular to the beam axis. Also, the experimental evaluation of our method on ultra-fast images sequences from carotid phantom was used to validate our method regarding the estimation of the pulse wave velocity, the Young’s modulus of the vessels wall, and the propagation of a longitudinal movement
Kohandani, Tafreshi Marzieh. "Reconstruction 3D du segment antérieur oculaire par échographie haute fréquence". Thesis, Brest, 2014. http://www.theses.fr/2014BRES0003.
Texto completoOphthalmology is one of the clinical application fields of ultrasound imaging, for which numerous specific issues arise, related in part to the eye’s small anatomical dimensions combined with the high level of accuracy requirements associated with intraocular measurements. Indeed, since the development of refractive surgery including all the techniques dedicated to the correction of refractive errors, as well as the emergence of intraocular lens (IOL), ophthalmic surgeons have to monitor overall acceptance as well as secondary effects related to these implants on the structures of the anterior eye segment. High frequency ultrasound imaging provides the required spatial resolution for this task. However, the development of 3D ultrasound imaging allows for the development of new applications in ophthalmology, for instance pre-operative dimensioning of the lens. 3D modelling of the anterior eye segment therefore allows studying the IOL behaviour and may help designing future personalized IOL tailored for each patient. Within this context, we present an original 3D segmentation and reconstruction method based on 3D models registration, dedicated to the anterior eye segment acquired in high frequency ultrasound imaging. We used a 3D ultrasound free-hand acquisition system, composed of a high frequency ultrasound probe and a localization module based on a camera and infrared markers. This 3D ultrasound system provides images along with associated 3D spatial positioning information. We were therefore able to develop an entire ultrasound images acquisition and processing chain. This allowed us creating realistic reference 3D models from sequences of ultrasound images of the anterior eye segment. We thus propose a method based on the iterative closest point (ICP) algorithm for the registration of the 3D reference models to 3D ultrasound acquired data. We have also selected and adapted various methods for the evaluation of the proposed reconstruction process. These methods highlight the accuracy of the obtained reconstructions
Laporte, Sébastien. "Reconstruction 3D du squelette humain pour la biomécanique par radiographie biplane à dose minimale d'irradiation". Paris, ENSAM, 2002. http://www.theses.fr/2002ENAM0024.
Texto completoGoubet, Étienne. "Contrôle non destructif par analyse supervisée d'images 3D ultrasonores". Cachan, Ecole normale supérieure, 1999. http://www.theses.fr/1999DENS0011.
Texto completoBarbosa, Daniel. "Automated assessment of cardiac morphology and function : An integrated B-spline framework for real-time segmentation and tracking of the left ventricle". Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0111.
Texto completoThe fundamental goal of the present thesis was the development of automatic strategies for left ventricular (LV) segmentation and tracking in RT3DE data. Given the challenging nature of RT3DE data, classical computer vision algorithms often face complications when applied to ultrasound. Furthermore, the proposed solutions were formalized and built to respect the following requirements: they should allow (nearly) fully automatic analysis and their computational burden should be low, thus enabling real-time processing for optimal online clinical use. With this in mind, we have proposed a novel segmentation framework where the latest developments in level-set-based image segmentation algorithms could be straightforwardly integrated, while avoiding the heavy computational burden often associated with level-set algorithms. Furthermore, a strong validation component was included in order to assess the performance of the proposed algorithms in realistic scenarios comprising clinical data. First, the performance of the developed tools was evaluated from a global perspective, focusing on its use in clinical daily practice. Secondly, also the spatial accuracy of the estimated left ventricular boundaries was assessed. As a final step, we aimed at the integration of the developed methods in an in-house developed software suite used for research purposes. This included user-friendly solutions for efficient daily use, namely user interactive tools to adjust the segmented left ventricular boundaries
Martin, Matthieu. "Reconstruction 3D de données échographiques du cerveau du prématuré et segmentation des ventricules cérébraux et thalami par apprentissage supervisé". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI118.
Texto completoAbout 15 million children are born prematurely each year worldwide. These patients are likely to suffer from brain abnormalities that can cause neurodevelopmental disorders: cerebral palsy, deafness, blindness, intellectual development delay, … Studies have shown that the volume of brain structures is a good indicator which enables to reduce and predict these risks in order to guide patients through appropriate care pathways during childhood. This thesis aims to show that 3D ultrasound could be an alternative to MRI that would enable to quantify the volume of brain structures in all premature infants. This work focuses more particularly on the segmentation of the lateral ventricles (VL) and thalami. Its four main contributions are: the development of an algorithm which enables to create 3D ultrasound data from 2D transfontanellar ultrasound of the premature brain, the segmentation of thigh quality he lateral ventricles and thalami in clinical time and the learning by a convolutional neural networks (CNN) of the anatomical position of the lateral ventricles. In addition, we have created several annotated databases in partnership with the CH of Avignon. Our reconstruction algorithm was used to reconstruct 25 high-quality ultrasound volumes. It was validated in-vivo where an accuracy 0.69 ± 0.14 mm was obtained on the corpus callosum. The best segmentation results were obtained with the V-net, a 3D CNN, which segmented the CVS and the thalami with respective Dice of 0.828± 0.044 and 0.891±0.016 in a few seconds. Learning the anatomical position of the CVS was achieved by integrating a CPPN (Compositional Pattern Producing Network) into the CNNs. It significantly improved the accuracy of CNNs when they had few layers. For example, in the case of the 7-layer V-net network, the Dice has increased from 0.524± 0.076 to 0.724±0.107. This thesis shows that it is possible to automatically segment brain structures of the premature infant into 3D ultrasound data with precision and in a clinical time. This proves that high quality 3D ultrasound could be used in clinical routine to quantify the volume of brain structures and paves the way for studies to evaluate its benefit to patients
Graciet, Christophe. "Imagerie quantitative par ultrasons de propriétés de matériaux composites". Bordeaux 1, 1996. http://www.theses.fr/1996BOR10574.
Texto completoElbes, Delphine. "Thermothérapies par ultrasons focalisés et radiofréquences guidées par imagerie de résonance magnétique". Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14683/document.
Texto completoMy manuscript studies the development of mini and non invasive thermotherapies guided by magnetic resonance imaging (MRI) in the treatment of hepatic and cardiac diseases. The first part was the development of a method to increase the lesion size, induced by HIFU, and based on bubble enhanced heating (BEH). The acoustic power threshold of the BEH was determined by MR acoustic radiation force imaging (MR-ARFI) and the thermal effect was characterized by MR thermometry on ex vivo and in vivo in pig livers. The second part developed a strategy to perform HIFU through the rib cage using beam steering to track the respiratory movement or to performed multipoint ablation while avoiding heating of ribs. Transducer elements localized in the geometric projection of the shadow of ribs, relatively to the targeted focal point, were switched off.The third part was the development of the MR thermometry on the heart for the monitoring of radiofrequency ablation (RFA). Several aspects were investigated, in particular the thermometry precision, the feasibility to perform catheter radiofrequency ablation under MR thermometry in vivo in a sheep heart, the possibility to use the catheter as an MR antenna to increase spatial resolution of MR thermometry images
MARTIN, DIDIER. "Propagation d'ondes et imagerie en milieux anisotropes par laser ultrasons". Paris 7, 1993. http://www.theses.fr/1993PA077185.
Texto completoGateau, Jérôme. "Imagerie ultrasonore ultrarapide d'évènements de cavitation : application en thérapie par ultrasons et imagerie de détection". Phd thesis, Université Paris-Diderot - Paris VII, 2011. http://pastel.archives-ouvertes.fr/pastel-00863591.
Texto completoGâteau, Jérôme. "Imagerie ultrasonore ultrarapide d'événements de cavitation : application en thérapie par ultrasons et imagerie de détection". Paris 7, 2011. http://www.theses.fr/2011PA077013.
Texto completoThe onset of cavitation activity in an aqueous medium is linked to the formation of gas/vapour-filled cavities of micrometric size. This formation can be acoustically mediated and is then called acoustic bubble nucleation. We focus here in the activation of seed nucléi by short (a few cycles) and high amplitude ultrasonic excitation (order of magnitude MPa). Bubbles are generated during the rarefaction phase of the wave and are transient (they dissolve). The nucleation properties of biological tissues are little known. However, they can be assessed using ultrasound: the formation of a bubble results in the appearance of a new scatterer (which can be detected with a pulse-écho detection), and each cavitation event generates an acoustic emission (detected with passive reception). In n this PhD manuscript, we use ultrafast ultrasound imaging (simultaneous acquisition on an array of transducers with a high frame rate) to detect cavitation events. Two in vitro applications were first validated. On one hand, bubble nucleation was performed through a human skull, and transcranial passive detection of a single cavitation event was used in a time reversal process to optimize adaptive focusing for thermal therapy of brain tissue. On the other hand, the formation and dissolution of bubbles in scattering biological tissues (muscle) were detected with a high sensitivity by combining passive detection and ultrafast active imaging. Finally, in vivo experiments on sheep's brain, and others in vitro on animal blood showed that nucleation in biological tissue is a random phenomenon, and high negative pressure are mandatory to initiate nucleation in vivo (< -12MPa)
Ruan, Yi. "Imagerie numérique 3D par microscopie tomographique diffractive". Ecole centrale de Marseille, 2012. http://www.theses.fr/2012ECDM0003.
Texto completoVernet, Kinson. "Imagerie densitométrique 3D des volcans par muographie". Electronic Thesis or Diss., Université Clermont Auvergne (2021-...), 2022. http://www.theses.fr/2022UCFAC112.
Texto completoMuography is an imaging technique in particle physics where atmospheric muons passing through a target are used to determine information about the interior of the target : density distribution or chemical composition via the atomic number. Depending on the energy of the muons and the amount of matter they have to cross, some of them will survive and others will be stopped by the target. And, the diffusion of the muons depends, to a first approximation, on their momentum and the average atomic number along their flight path. Muography proposes, from the measurement of the transmission and/or diffusion of muons through a target, to provide information about its interior.There are currently two types of muography : transmission muography, where the transmitted flux of muons through the target is measured to infer the density distribution of that target, and diffusion muography, where the diffusion of muons through the target is used to determine the distribution of the atomic number of the target. This thesis discusses transmission muography in order to radiography volcanoes.In the case of transmission muography, a muon telescope is used to measure the transmitted flux of atmospheric muons through the target. This flux is, to a first approximation, a bijective function of the amount of matter encountered by the muons. The idea is to invert the measured number of muons into a density estimation of the target.There are other imaging methods in geophysics that can be used to reconstruct the density of a target. This is the case, for example, of gravimetry and seismic imaging. These so-called conventional methods have weaknesses. For these methods, the inversion problem is either ill-posed, i.e. there is no unique solution, or the solution presents large variations for small variations of the parameters on which it depends. A set of additional constraints are then added to remove the non-uniqueness.In muography however, the inversion problem is well posed and the solution is unique. Conventional geophysical methods alone cannot determine the density of a target. Combined with muography, they have great potential, either by providing other information on the rock and/or on the nature of the water, or by improving the accuracy of the target density reconstruction.Several experiments use the CSDA (Continuous Slowing Down Approximation) approximation to estimate the survival probability of muons through a target. Using this approximation, thus neglecting the stochastic character of the interaction of muons with matter, underestimates the muon survival probability and therefore induces systematic effects on the density reconstruction. In standard rock kilometers the effect is 3% - 8% depending on the modeling of the interaction of high energy muons with matter. In addition, a bad estimation of the background of the low momentum muons affecting the measurement of the signal results in an underestimation of the density of the target with respect to the gravimetry. This probably comes from the use of the analytical approximation to simulate the propagation of the muons through the target and the difficulty of rejecting in the measurement those with low momentum. For these reasons, in the Muon IMaging (MIM) experiment (where this thesis was conducted), we use a Monte Carlo treatment to simulate the muon transport through the target. In this case, we can accurately estimate the effet of these low momentum muons on the density reconstruction. One of the techniques used in our experiment, to make the low momentum muons scatter so that they can be statistically rejected, is to insert a thickness of lead between the telescope detection planes. (...)
Bensalah, Mohamed Sélim. "Caractérisation de l'os cortical par imagerie 3D". Paris 7, 2012. http://www.theses.fr/2012PA077012.
Texto completo3D characterization of trabecular bone has been widely studied, whereas few studies have focused on cortical bone despite its role in the mechanical strength of bone. Bone remodeling of the cortical bone leads to changes in size, shape and surface (with variations of the roughness related to the osteoclasts activity) of the pores of the cortical bone which consist essentially by Haversian canals and Volkmann. This process leads to cortical bone trabecularization. The 3D characterization of cortical bone can be performed using the usual parameters (derived from thé trabecular analysis) such as porosity, pore number, pore spacing, the pore diameter. . . However, these parameters describe the cortical bone structure globally and do not reflect changes related to each pore individually. Therefore, we suggested in this thesis new parameters to characterize the branching degree, the roughness and sinuosity/tortuosity of cortical bone pores. Our study is based on images of samples extracted from different femur sites (diaphysis , lower and upper neck) and acquired by synchrotron radiation micro-tomography with voxel size 2. 8um and 7. 5uni. The segmentation (canals Vs bone) using a simple threshold is sufficient to reach an accurate separation because of high contrast. However, the segmentation between osteons and cortical tissue, because of low contrast, is difficult. Therefore we developed a new method of 3D segmentation of osteons and various components of the cortical bone (canal, osteoid bone, interstitial bone) based on 3D Markov Random Fields (3D-MRF). Four 3D-MRF models have been suggested and compared to manual segmentation considered as reference segmentation
Heiles, Baptiste. "Microscopie par Localisation Ultrasonore en 3D". Thesis, Paris Sciences et Lettres (ComUE), 2019. https://pastel.archives-ouvertes.fr/tel-02953081.
Texto completoUltrasound Localization Microscopy has demonstrated the ability to overcome the penetration/resolution conundrum in ultrasound imaging thanks to high frame rate imaging and contrast agents. However, this approach will fall short in its clinical translation if its main disadvantages aren’t addressed: 1- long time of acquisition 2- limited two dimensional field of view 3- motion artifacts 4-data overdose and 5- data processing times. Developing 3D ULM will allow to explore entire volumes within a few minutes of acquisition, giving access to all blood vessels down to micrometer size and imaging moving organs (i.e. a patient in a clinical setting).The objective of this thesis was to perform, for the first time, volumetric ultrasound localization microscopy and unveil its potential in-vitro and in-vivo. For this purpose, I first developed new post-processing techniques, reducing 2D data processing times by a factor of 300, allowing implementation of ULM on 3D data and increasing image quality. Then, I implemented new ultrasound sequences and demonstrated that sub-wavelength features could be resolved in a tailor made wall-less phantom. I then demonstrated that 3D imaging of the rat brain microvasculature with blood flow velocimetry was achievable with micrometric resolution, and implemented 3D motion correction and image registration to provide whole brain imaging.This new tool was used to investigate both the anatomy and the vascularization mechanisms in the brain. Making the transition from 2D ULM to 3D ULM paves the way towards better imaging of in vivo organs in the rat. Thanks to technological improvements 3D ULM will spread fast in research imaging and reach all the way to clinical care
Roux, Christian. "Evaluation de l'os humain par ultrasons : application à l'ostéoporose". Compiègne, 1997. http://www.theses.fr/1997COMP1049.
Texto completoGesnik, Marc. "Imagerie fonctionnelle par ultrasons de la rétine et des fonctions visuelles cérébrales". Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLET011/document.
Texto completoThis thesis focuses on recent improvements in the functional ultrasound imaging (fUS) technique and their applications in the field of ophthalmology. Within the framework of a synergetic project blending waves physics, medical imaging, neuroscience and ophthalmology, fUS was shown to be capable of imaging and studying the visual system of healthy and diseased animals for the purpose of preclinical studies. To tackle these issues, constant upgrades in the fUS technique had to support the preclinical studies.An experimental set-up was built to image the visual pathway in three dimensions with fUS. Using a new imaging facility, fUS was proven to be feasible in real time and at high ultrasound frequencies such as 30 MHz. Interleaved sampling had to be implemented in that case. Furthermore, the a priori knowledge of the vascular cerebral architecture and the Doppler Effect were exploited to spectrally decompose cerebral blood flux and vessels according to their velocities and orientations.Leveraging these improvements, functional ultrasound imaging of rats and non-human primates was performed. Primate retina was imaged with Power Doppler, but proved to be too mobile to be functionally imaged. However, fUS has been performed on rat retina after 30 MHz fUS imaging had been implemented. The rat visual pathway has then been characterised with fUS. Some of its known features where highlighted such as its retinotopic organisation or the time response differences between some of its structures. The same set-up has been leveraged to map the cerebral activity of animal that underwent visual restauration therapies. These tools were then used to map cerebral activity in anesthetized and awake and behaving monkeys. Unique blood volume variations due to unique mistakes were detected. These tools were finally applied to two preclinical trials on a depressive state of the brain vascular contractility. Blood volume and blood velocity changes were highlighted throughout an acute and a chronical study
Sandrin, Laurent. "Elastographie impulsionnelle par ultrasons : du palpeur acoustique à l'imagerie ultrarapide". Paris 6, 2000. http://www.theses.fr/2000PA066538.
Texto completoBleuet, Pierre Magnin Isabelle. "Reconstruction 3D par tomosynthèse généralisée application à l'imagerie médicale par rayons X /". Villeurbanne : Doc'INSA, 2004. http://docinsa.insa-lyon.fr/these/2002/bleuet/index.html.
Texto completoBleuet, Pierre. "Reconstruction 3D par tomosynthèse généralisée : application à l'imagerie médicale par rayons". Lyon, INSA, 2002. http://theses.insa-lyon.fr/publication/2002ISAL0059/these.pdf.
Texto completoThis work deals with reconstruction in digital medical tomosynthesis. This technique allows, starting from a low number of projections (typically twenty) acquired on a digital detector, to obtain three-dimensional information on the structure of the studied object. The main advantage of this technique is the ability to obtain such information using a standard radiological remote table with a digital detector. The X-Ray tube and detector are moving along a specific path defining the acquisition geometry. Furthermore, the total exam dose is equivalent to a single radiograph dose. The main drawback of this acquisition technique is the significant lack of data, and more particularly the limited angle of view which significantly restricts the vertical spatial resolution. From the mathematical point of view, the problem of reconstruction is a severely ill-posed inverse problem : angular range is limited, and only a few possibly noisy number of projections is available. We inverse this problem using the algebraic methods and more particularly the algorithms ART (Algebraic Reconstruction Technique). This type of method makes it possible to improve the resolution but does not deals with the noise problem. In order to improve the quality of the reconstructed object, we adapted the half-quadratic minimization algorithm in this tomosynthesis context. In order to limit the computation time, we developed a dedicated reconstruction and regularization scheme that allows to decompose the volume of interest into a series of independent reconstructed planes. Other processing are necessary to reconstruct high quality tomosynthetic slices. We propose a method to reduce truncation artifacts related to high projection angles and a metal artifacts reduction algorithm due to the possible presence of surgical prostheses within the body. In order to test and validate our approach, we built a radiological remote table with a certain flexibility in the acquisition geometry. Finally we show that it is possible to reconstruct large size images for thoracic imaging with a vertical resolution of about 1cm and a spatial resolution in the detector plane equal to the detector resolution (about 100 μm). For other bone-related applications such as the radiography of ankle or pedicular screwing, the results are very satisfactory in terms of image quality and artifacts suppression
Turquin, Emeline. "Imagerie tissulaire ultrasonore 3D pour l’étude de l’anisotropie locale du muscle cardiaque". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1213/document.
Texto completoUltrasound imaging has strongly developed in recent years. It reaches now a frame rates of several thousand images per second, thanks to the emergence of ultrafast imaging. It is therefore the most suitable modality for cardiac applications. Not only does it allow the reconstruction of images, it also enables the extraction of parameters for tissue characterization, such as local anisotropy inside the heart muscle. Indeed, this fibrous layout can be modified in the case of cardiac pathologies. The aim of this doctoral work is the development of a method to extract the local orientation of an anisotropic environment by 3D ultrasound imaging. This approach should allow imaging with a wide field a view to be applied in cardiac imaging. Finally, the validation of the processing chain is necessary. To address these issues, several solutions have been proposed. First, the local orientation was evaluated using a spatial coherence method. It allowed assessing the orientation of fibres in a plane parallel to the surface of the probe. Once developed and validated, this strategy was extended to extract the local orientation in 3D and not only the angle in a plane. Finally, the study of different types of transmissions was also carried out in order to widen the imaged field of view. All these original methods have been applied and validated on phantom and in vivo data: the determination of the local orientation of an anisotropic environment was first performed on a monodirectional phantom and then on the biceps of a volunteer. For this purpose, an experimental system consisting of four research ultrasound scanners was developed thanks to the sharing of equipment from CREATIS and LabTAU, another laboratory in Lyon, in order to acquire 3D data. This work has thus made it possible both to extend an anisotropic environment to the case of an orientation not parallel to the surface of the probe and to improve the size of the field of view of the existing method. The validation of the entire processing chain has been completed. Applying this method to in vivo cardiac tissue is directly part of future studies
Bajard, Alban. "Numérisation 3D de surfaces métalliques spéculaires par imagerie infrarouge". Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00845939.
Texto completoWang, Fan. "Imagerie nanométrique 2D et 3D ultrarapide par diffraction cohérente". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112226/document.
Texto completoCoherent diffraction is an amazing art by its experimental simplicity: a coherent XUV source illuminates a single, isolated sample, and the diffraction pattern of the object is recorded by a CCD camera. An inversion of the diffraction pattern to an image in real space is possible through an approach based on iterative algorithms. The techniques for Fourier transform holography, for which reference is placed near the object to be imaged, allow the direct reconstruction of the image, even when the quality of the experimental data is worse. We have a laboratory sufficiently intense compact XUV source for this type of experience. The ultrashort XUV pulses (from femtosecond to attosecond) are produced by selecting high order harmonics of a femtosecond infrared laser which is focused into a cell of rare gas. We recently demonstrated the feasibility of using this source for coherent diffraction imaging with a spatial resolution of 78 nm. Furthermore, we demonstrated experimentally a holographic technique with extended reference and obtained a resolution of 110 nm in single shot (i.e. an integration time of 20 femtoseconds). A perception of an object in three dimensions gives us a better understanding thereof. A nanoscale 3D imaging techniques are from tomographic techniques of electron microscopy. However, many shots required (from different angles) make these techniques obsolete during the study time-resolved irreversible phenomena on non-reproducible samples. In this context, the aim of my thesis is to extend the 2D imaging techniques for 3D perception of nanoscale (physical, biological ) objects, while preserving the ultrafast appearance. The development of a new technology of 3D coherent imaging in single view, named ‘ankylography’, proposed by Professor Miao J. UCLA [Raines et al., Nature 2010] was made in progress. This technique allows reconstructing a 3D image of the sample after a single diffraction image. Its basic principle is to find the depth of a 3D object by the longitudinal constructive interference. However, this technique is more requested in both the quality of experimental data and the computer hardware and analysis. The other idea for 3D imaging is to imitate human vision using two coherent beams X arriving simultaneously on the sample but with a small angle. In this scheme, we use references near the target object (i.e. holography) to improve the signal to noise ratio in the diffraction pattern (hologram). Two holograms are then collected on the same detector. The inverse Fourier of each hologram forms two images from different views of the object. Parallax is thus produced. The stereo reconstruction of the object is performed by computer. Finally, the demonstration of applications will be considered after my thesis. This imaging of biological objects (such as nanoplanktons already collected and prepared CEA). And we are also interested in the study of 3D nanoscale objects (azo-polymers) movement on ultrashort time. Furthermore, another important application will be to study the ultra-fast phase transition such as nano-magnetic field where demagnetization phenomena induced by femtosecond pulse occurs
Severac, Hélène. "Simulation et caractérisation 3D de composants par imagerie thermoacoustique". Toulouse, INPT, 1995. http://www.theses.fr/1995INPT088H.
Texto completoSouchon, Rémi Chapelon Jean-Yves. "Application de l'élastographie à l'imagerie du cancer de la prostate et à sa thérapie par ultrasons focalisés rostate cancer detection and HIFU therapy monitoring using elastography /". Villeurbanne : Doc'INSA, 2005. http://docinsa.insa-lyon.fr/these/pont.php?id=souchon.
Texto completoThèse rédigée en anglais. Introduction et conclusion en français et en anglais. Titre provenant de l'écran-titre. Bibliogr. p. 113-118. Publications de l'auteur, 3 p.
Legland, David. "Morphométrie de structures cellulaires biologiques partiellement observées par imagerie 3D". Paris 5, 2005. http://www.theses.fr/2005PA05S039.
Texto completoThis work presents methods to characterize morphology of 3D cellular structures partially observed by discrete images, as well as their application to morphometric description of tomato pericarp. An estimation method of geometric properties of a material was developed, in the particular case where the sampling probability of pixels is not uniform inside the image. The principle is to express locally the morphological parameters of the structure, and te weight each contribution by the inverse of its sampling probability. We present also the computation of sampling prohabilities in 3D images acquired perpendicularly to a smooth surface, based on simple regularity assumptions. In order te compare the quality of information obtained with 2D and 3D images, the estimation of surface density in vertical sections was applied to discrete images. Finally we present an integramed approach to characterize a cellular material, the tomato pericarp. This approach comprises the acquisition of images using confocal microscopy, image processing to segment biological cells, and the application of estimators we developed. We could characterize the morphologv of tomato pericarp cells globally and as a function of depth in the pericarp
Delestre, Barbara. "Reconstruction 3D de particules dans un écoulement par imagerie interférométrique". Electronic Thesis or Diss., Normandie, 2022. http://www.theses.fr/2022NORMR116.
Texto completoFor many industrial or environmental applications, it is important to measure the size and volume of irregularly shaped particles. This is for example the case in the context of aircraft icing which occurs during flights, where it is necessary to measure in situ the water content and the ice content in the troposphere in order to detect and avoid risk areas. Our interest has been on interferometric out-of-focus imaging, an optical technique offering many advantages (wide measurement field, extended range of sizes studied [50 μm: a few millimeters], distance particle / measuring device several tens of centimeters ...). During this thesis, we showed that the 3D reconstruction of a particle can be done from a set of three interferometric images of this particle (under three perpendicular viewing angles). This can be done using the error reduction (ER) algorithm which allows to obtain the function f(x,y) from the measurements of the modulus of its 2D Fourier transform |F(u,v)| , by reconstructing the phase of its 2D Fourier transform. The implementation of this algorithm allowed us to reconstruct the shape of irregular particles from their interferometric images. Experimental demonstrations were carried out using a specific assembly based on the use of a micro-mirror array (DMD) which generates the interferometric images of programmable rough particles. The results obtained are very encouraging. The volumes obtained remain quite close to the real volume of the particle and the reconstructed 3D shapes give us a good idea of the general shape of the particle studied even in the most extreme cases where the orientation of the particle is arbitrary. Finally, we showed that an accurate 3D reconstruction of a "programmed" rough particle can be performed from a set of 120 interferometric images
Macé, Emilie. "Développement d'une nouvelle modalité d'imagerie fonctionnelle cérébrale et étude de l'élasticité du cerveau par ultrasons". Paris 7, 2012. http://www.theses.fr/2012PA077212.
Texto completoIn this thesis, we investigate the possible contribution of ultrafast ultrasound imaging in neuroimaging. Ultrafast imaging is a technique using plane wave emissions to acquire ultrasonic images at high frame rate (~ 20 kHz). First, we developed a new brain functional imaging modality called functional ultrasound (fUS) that can image the whole brain at high spatiotemporal resolution (100 μm, 200 ms). For that, we combined ultrafast imaging and synthetic focusing in emission to increase the sensitivity of Doppler imaging by a factor 100 and thus to detect blood flow in cerebral microvessels whose dynamics is linked to local neuronal activity. We validated fUS by mapping in vivo the brain activation induced by various sensory stimuli. Then, we were able to follow by fUS the dynamics of an epileptic seizure, a pathology very challenging for imaging up to now. Finally, we designed a fUS sequence with higher temporal resolution (30 ms) to observe the effect of pulsatility on cerebral blood flow. In a second step, we adapted the "Supersonic Shear Imaging" technique based on ultrafast imaging to map brain elasticity. We then applied it to a rat model of transient cerebral ischemia. We observed for the first time the softening of ischemic tissue and, simultaneously, we followed the stroke impact on brain microvascularization with our new Doppler mode. These new modes are promising not only in neuroscience research but also for their clinical applications in pediatry and neurosurgery
Souchon, Rémi. "Application de l'élastographie à l'imagerie du cancer de la prostate et à sa thérapie par ultrasons focalisés". Lyon, INSA, 2004. http://theses.insa-lyon.fr/publication/2004ISAL0018/these.pdf.
Texto completoAn ultrasonic imaging device for prostate elastography was developed. A balloon filled with a coupling liquid served as a compressor. In vitro, the system was capable of imaging the anatomy of the prostate as well as benign and malignant tumors. Then the major influence of the acquisition frame on the image quality in vivo was demonstrated. The system was shown to be able to detect prostate cancer and to visualize the effects of high intensity focused ultrasound (HIFU) therapy in vivo. It was finally shown in vitro that the formation of an elementary HIFU lesion could be observed by passive elastography, using only temperature elevation to create the elastogram
Heurtebise, Xavier. "Représentation multirésolution et déformation d’objets 3D définis par énumérations spatiales". Aix-Marseille 1, 2007. http://www.theses.fr/2007AIX11074.
Texto completoBouvier, Caroline. "Étude du vieillissement de peintures anciennes par imagerie par spectrométrie de masse 3D". Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS008.
Texto completoThe objective of the PhD was to evaluate the potential of TOF-SIMS imaging, particularly 3D, to reliably study chemical composition in stratigraphic sections of ancient paintings. TOF-SIMS imaging can simultaneously map organic and inorganic materials at the micrometer scale, providing answers to questions about ancient paintings, such as elucidating the nature of the binders and pigments in the various layers, or studying the chemical transformations of ingredients through the action of time and interactions. The construction of a database of TOF-SIMS mass spectra for reference materials in parallel with the study of several samples of old paintings, has allowed to identify which reliable chemical information can be associated with the use several centuries ago of a given ingredient according to a certain painting technique. The references and the parameters of the analyses were adapted according to the observations made on the cross sections. The identification of drying oils and egg yolk was considered. Different surface preparations and secondary ion extraction parameters were compared to optimise the detection of surface-formed ionic species and obtain more representative chemical information. The conditions under which argon aggregate sputtering can be used were defined. A preliminary analysis of the contribution of TOF-SIMS imaging to the understanding of the structure of dried drying oils has provided results that will be continued in the future
Lötjönen, Jyrki. "Modélisation géométrique 3D du thorax par triangulation déformable : application en bioélectromagnétisme". Lyon, INSA, 2000. http://www.theses.fr/2000ISAL0106.
Texto completoElectro- and magneto encephalographic (EEG and MEG) as well as electro- and magneto cardio-graphic (ECG and MCG) recordings have been proved useful in non invasively extracting information on human bioelectric activity. The recovery of activity sources and location needs solving the inverse problem knowing patient anatomy. In this work, a methodology has been developed to construct patient specific boundary element models for bioelectromagnetic (BE) inverse problems from magnetic resonance (MR) data volumes as well as from 2 orthogonal X-ray projections. The complete model includes the torso, lungs and pericardium external surfaces. The process consists of three steps: reconstruction of 3-D patient geometry, triangulation, registration of the mode! with the BE data. The 3-D geometry is reconstructed by matching a 3-D deformable boundary element template to the MR data. The defom1ation results from an energy minimization process including image and model based terms. The robustness of the matching is improved by multi-resolution and global to local approaches as well as using oriented distance maps. A boundary element template is al so used when 3-D geometry is reconstructed from 2 X-ray projections. The deformation is computed in 2-D by matching the template projected contours with the real contours extracted from the data. Then the produced 2-D vector field is back-projected and interpolated on the 3-D template. A marching cube triangulation is computed from the reconstructed 3-D geometry followed by a non-iterative 3D surface mesh-simplification step. It is based on the Voronoi-Delaunay duality with discrete distance measures. Finally, the triangulated surfaces are registered with BE data utilizing markers. More than 50 boundary element models have been successfully constructed from MR images using our method. We demonstrated the feasibility of reconstructing such a mode! from 2 X-ray projections but practical problems remain to be solved before processing real data
Hernandez-Hoyos, Marcela. "Segmentation anisotrope 3D pour la quantification en imagerie vasculaire par résonance magnétique". Lyon, INSA, 2002. http://theses.insa-lyon.fr/publication/2002ISAL0039/these.pdf.
Texto completoThe purpose of this work is the segmentation of three-dimensional vascular images obtained by magnetic resonance. Clinical application in view is the quantification of arterial stenoses. We propose a method for vessel segmentation, divided into two stpes: vessel axis extraction and detection of vessel contours in the planes locally perpendicular to the axis. Our main contribution is automatic vessel centerline extraction method based on extensible-skeleton model whose growth is driven by multi-scale analysis of the inertia tensor. This analysis provides information about the orientation, diameter and local shape of the vessel in each point of its axis. The vessel is roughly reconstructed using a binary volume composed by a union of spheroids centered on the axis, oriented according to the vessel local orientation and adapted to the vessel local size. Based on the same theoretical principles, we propose a method for semi-automatic detection of arterial bifurcations. Recursive processing of bifurcations aims at extraction of the entire vascular tree. Calculation of stenosis parameters is based on the extraction of planar contours. To this purpose, we implemented two algorithms. The first one is based on iso-contours extraction using an adaptive local threshold. The second one uses a normalized-length active contour model. These algorithms have been implemented in user-friendly software called MARACAS (Magnetic Resonance Angiography Computer Assisted Analysis) that underwent a clinic pre-validation on images of 6 vascular phantoms and clinical data of 27 patients
Hernandez-Hoyos, Marcela Magnin Isabelle Orkisz Maciej Douek Philippe. "Segmentation anisotrope 3D pour la quantification en imagerie vasculaire par résonance magnétique". [S.l.] : [s.n.], 2002. http://csidoc.insa-lyon.fr/these/2002/hernandez_hoyos/index.html.
Texto completoProvencher, David. "Imagerie 3D de l'anatomie interne d'une souris par dynamique de fluorescence". Mémoire, Université de Sherbrooke, 2012. http://hdl.handle.net/11143/6205.
Texto completoSebbahi, Ali. "Segmentation 2D et 3D par modèles déformables en imagerie cardio-vasculaire". Paris 12, 1995. http://www.theses.fr/1995PA120040.
Texto completoDaanen, Vincent. "Suivi 3D de gestes chirurgicaux : application à l'IRM interventionnelle". Lille 1, 2001. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2001/50376-2001-19-20.pdf.
Texto completoDaanen, Vincent Vasseur Christian. "Suivi 3D de gestes chirurgicaux application à l'IRM interventionnelle /". [S.l.] : [s.n.], 2001. http://www.univ-lille1.fr/bustl-grisemine/pdf/extheses/50376-2001-19-20.pdf.
Texto completoBen, Bouallegue Fayçal. "Contributions en reconstruction TEP 3D par inversion directe". Montpellier 2, 2009. http://www.theses.fr/2009MON20078.
Texto completoWe present two innovative contributions in 3D positron emission tomography (PET) direct reconstruction. First, we develop an extended three-dimensional exact rebinning formula in the Fourier space that leads to an iterative reprojection algorithm (iterative FOREPROJ), which enables the estimation of unmeasured oblique projection data on the basis of the whole set of measured data. In first approximation, this analytical formula also leads to an extended Fourier rebinning equation that is the basis for an approximate reprojection algorithm (extended FORE). These algorithms are evaluated on numerically simulated 3D PET data for the solution of the truncation problem. By taking advantage of all the 3D data statistics, the iterative FOREPROJ reprojection provides a quick and reliable alternative to the classical FOREPROJ and geometric re-projection methods. It significantly improves the quality of the external reconstructed slices without loss of spatial resolution. Then we investigate how the choice of fixed planes for the representation of the projection data of a cylindrical PET scanner simplifies the frequency interpolation required by the 3D Fourier slice theorem (3D-FST). A new gridding algorithm based on a two-plane geometry and requiring only 1D interpolations in the Fourier domain is compared with the direct implementation of the 3D-FST. We show that the use of two orthogonal planes leads to signal to noise ratios similar to those achieved with the 3D-FST algorithm from projection data acquired with up to two times more count rates, while the resolution remains similar
Lucidarme, Olivier. "Quantification non invasive de la microcirculation par imagerie ultrasonore fonctionnelle de contraste avec les techniques de destruction reperfusion". Paris 12, 2003. https://athena.u-pec.fr/primo-explore/search?query=any,exact,990002118320204611&vid=upec.
Texto completoOur aim was to study the potential for quantitative contrast enhanced functional ultrasound imaging (fUSI) to assess microcirculation. We described in vitro and in vivo the "entrance in the section phenomenon" that introduces a distortion of the refilling curves when the vessels that feed the region or interest have previouslv traveled across the ultrasound tield. We validated in vitro a b model based on the destruction phase of microhuhbles during ultrasound emission. This model allows the estimation of quantitative flow data during acquisitions of only 1 or 2 seconds. We finally studied a non tumor angiogenesis model in 36 mice. Ultrasound measurement (during the destruction phase) ot' the Uractional blood volume in a gel impregnated with growth exhihited a higher correlation vith the fractional vascularized area of gel than with the microvascular density. Microbubble velocity assessed on fUSI did not change as mi crocirculation increased