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1
Alloulah, Mohammed. "Real-time tracking for airborne broadband ultrasound." Thesis, Lancaster University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.587053.
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Context refers to a collection of elements with which people associate situations. The location and state of objects in an environment constitute an important subset of context, which has been thoroughly researched and established. By tracking the movement of people and objects within an environment, context-aware applications may be realized, enabling a host of interaction schemes that are intuitive, utilitarian, and fun. Many sensing technologies have been shown to supply tracking services to context-aware systems. These sensing technologies are complementary, and none possesses all desirable tracking attributes for all situations. The preference for the use of a particular tracking technology is often much dependent on the application at hand. Ad hoc, mobile applications are particularly hard to satisfy, given their dynamic nature and the centralized, infrastructure-reliant arrangement of most of the accurate tracking systems available. The first part of this dissertation describes methods for embedded, real-time airborne broad band ultrasonic tracking. The tracker has been built around the assumption of a mobile operation that is deployed ad hoc and upon demand. In order for this to happen, the embedded, real-time operation of sensor nodes has been emphasized. The efficient signalling designs that make way for multiuser, ad hoc tracking deployment have been thoroughly characterized, and shown to perform close to their infrastructure-reliant counterparts. System-level parameterization of tracking is also possible subject to application needs. The remainder of this work shows for the first time in literature that real-time Doppler processing in the airborne broadband ultrasonic modality is possible, whereby velocity inference of mobile nodes is facilitated. Building on advancements from underwater acoustics research, a complex Doppler receiver has been derived and characterized. Its implications on real-time realizations have been studied and characterized utilizing a high-level synthesis architectural exploration methodology. This has revealed that it is feasible to implement real-time Doppler tracking for airborne broadband ultrasound using modern reconfigurable fabrics (i.e. FPGAs). The dissertation concludes by examining the applicability of findings on even more complex forms of processing such as multiuser direction-of-arrival estimation by means of beamforming, and binary Doppler-tolerant reception.
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Al-Mejrad, Ali Saleh Khalid. "Medical ultrasound : a study of real-time three dimensional ultrasound imaging." Thesis, University of Edinburgh, 1996. http://hdl.handle.net/1842/21190.
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Ultrasonic techniques are very widely applied in medicine. Real-time two dimensional imaging is a technology which is extremely well-suited to medical applications since it enables moving structures to be observed and rapid searching through tissue structures to be performed. Three-dimensional (3D) ultrasonic imaging techniques have been developed but to date there has been very limited success in the development of real-time versions. The aim of this thesis is to study the feasibility of real-time 3D ultrasonic imaging to see if ways can be found to overcome the fundamental problem of sparcity of echo line data when a volume is scanned in real-time. The fundamental problem arises because conventional ultrasonic scanners have an upper limit of rate of generation of scan lines of around 10 KHz. The number of scan lines in each scanned volume is therefore low e.g. 2000 for a volume scan rate of 5 volumes per second. The aim of this thesis is to investigate whether or not modern electronic and image processing techniques can overcome this fundamental problem. During the first phase of our study, a microcomputer based C-scan test-rig system including hardware and software has been constructed to investigate the effectiveness of real-time image processing in compensating for the fundamental sparcity of echo data. This was investigated initially since C-scans suffer from the same sparcity of echo data as 3D scans. After the promising results obtained from this system using a number of image processing techniques, a hand-held 3D ultrasound system including hardware and software based on one of the commercial scanners (Dynamic Imaging C2000) has been constructed to extend our study to 3D. A number of test objects in addition to volunteers were scanned to investigate the feasibility of real-time 3D ultrasound imaging. Finally, a specification for real-time ultrasound imaging is discussed.
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Sundén, Erik. "Real-time DVR Illumination Methods for Ultrasound Data." Thesis, Linköping University, Department of Science and Technology, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-57540.
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Ultrasound (US) volume data is noisy, so traditional methods for direct volume rendering (DVR) are less appropriate. Improved methods or new techniques are required. There are furthermore a high performance requirement and limited pre-processing to be considered in order for it to be used interactively, since the volume data might be time-varying.
There exist numerous techniques for improving visual perception of volume rendering, and while some perform well and produce a visually enhanced result, many are designed and compared for use with medical data that has a high signal-to-noise ratio. This master thesis describe and compare recent methods for DVR illumination, in the form of ambient occlusion or direct/indirect lighting from an external light source. New designs and modifications are introduced for efficiently and effectively enhancing the visual quality of DVR with US data. Furthermore, this thesis addresses the issue of how clipping is performed during rendering and for the different illumination techniques, which is commonly used in ultrasound visualization.
This diploma work was conducted at Siemens Corporate Research in Princeton, NJ where the partially open source framework XIP is developed. The framework was extended further to include modern methods for DVR illumination that are described in detail within this thesis. Finally, presented results show that several methods can be used to visually enhance the visualization within highly interactive frame-rates.
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Ludvigsen, Holger. "Real-Time GPU-Based 3D Ultrasound Reconstruction and Visualization." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for datateknikk og informasjonsvitenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11798.
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Ultrasound scanning is frequently used in medical practice because it is a non-invasive, safe and low-cost solution (vs. CT or MR). However, conventional ultrasound probes only provide 2D scans. 3D ultrasound reconstruction builds 2D scans into 3D volumes of the patient's internals. Since these volumes can be used for acquiring out-of-angle views, 3D rendering of the anatomy, and for image guided surgery, they are rapidly expanding the possible uses of ultrasound. However, the 3D reconstruction process is computationally demanding and includes processing millions of picture and volume elements. This process can currently take minutes or even hours on conventional systems. It is very desirable to reconstruct ultrasound images in real-time to guide surgeons doing surgery. In this thesis, we manage to achieve this by utilizing the parallel processing power of GPUs with hundreds of computing cores. Our novel optimized methods take advantage of this power in order to perform entire volume reconstructions in only fractions of a second. Several optimization techniques have been developed, including only processing the relevant parts of the input. Novel methods for real-time incremental reconstruction producing high-quality results based on advanced interpolation techniques, are also presented. Using our novel pixel-based and voxel-based methods, we are able to generate a volume of 67 million voxels in on 0.9 and 0.6 seconds, respectively. These results are based on the new NVIDIA Fermi GPUs, OpenCL and 434 tracked ultrasound scans. For high-quality incremental reconstruction, real-time processing times are obtained for methods based on distance weighted orthogonal projections and on the probe trajectory (PT). Our GPU implementations give a performance speedup of 14 for pixel-based methods, an impressive 51 for voxel-based methods, and speedup of 6-8 for the incremental methods, compared with single-threaded CPU implementations. The cubic interpolation of the PT method is shown to be superior to the others and preserves the most details. As for possible future work, we point out techniques for handling memory constraints, complex probe movement and the device-to-host transfer bottleneck.
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González, Bellido Eduardo André. "Real-time quantitative sonoelastography in an ultrasound research system." Master's thesis, Pontificia Universidad Católica del Perú, 2017. http://tesis.pucp.edu.pe/repositorio/handle/123456789/9511.
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Quantitative Sono-Elastographie ist eine neue Technologie für die Ultraschall Bildgebung,
die Radiologen maligne Tumoren ohne Risiko der strahlungsinduzierten Krebs
(d.h. Mammographie) zu erfassen können. Aufgrund gefunden Rechenkomplexität
in der aktuellen Algorithmen, Implementierung von Echtzeit-Anwendungen, die Prüfungsverfahren
profitieren wurde jedoch noch nicht berichtet. Zusätzlich, aktuelle
Schätzer für die Darstellung eine Elastizität Bilder vorhanden Artefakte der hohen
Schätzung Varianz, die die Techniker in die Gegenwart steifer Massen irreführen könnten
und zwar, falsch-positive Diagnose zu erzeugen.
In dieser Arbeit wird eine GPU-basierte Elastographie-System entwickelt und an
einem Forschungsultraschallgeräten implementiert. Quantitative Elastizität in Echtzeit
bei 2 FPS mit einer Verbesserung Rechenzeitfaktor aus 26 wird gezeigt. Validierung der
Systemgenauigkeit Anzeige wurde, auf Gelatinebasis Gewebe Phantome durchgeführt.,
waren niedrige Vorspannung der Elastizitätswerte berichtet wurde (4,7 %) bei geringe
Anregungsfrequenzen nachahmt. Ausserdem wird eine neue Elastizität Schätzer auf
quantitative Sono-Elastographie basiert eingeführt. Ein lineares Problem wurde entlang
der seitlichen Abmessung modelliert und eine Regularisierung Methode wurde
implementieren. Elastizität Bilder mit niedriger Vorspannung wurde darstellen (1,48
%) sowie seine Leistung in einer Brust kalibrierte Phantom mit verbesserter CNR (47,3
dB) im Vergleich mit anderen Schätzer ausgewertet sowie die Verringerung Seiten Artefakte
bereits erwähnt in der Literatur (PD: 22,7 dB, 1DH 28,7 dB) gefunden. Diese
zwei Beitrag profitieren, die Umsetzung und Entwicklung weiterer Elastographie Techniken,
die eine verbesserte Qualität der Elastizität Bilder liefern könnten und somit
eine verbesserte Genauigkeit der Diagnose.Quantitative sonoelastography is an alternative technology for ultrasound imaging that helps radiologist to diagnose malignant tumors with no risk of radiation-induced cancer (i.e. mammography). However, due to the high computational complexity found in the current algorithms, implementation of real-time systems that could benefit examination procedures has not been yet reported. Additionally, elasticity maps depicted from current estimators feature artifacts of high estimation variance that could mislead the technician into the presence of stiffer masses, generating false positive diagnosis. In this thesis, a GPU-based elastography system was designed and implemented on a research ultrasound equipment, displaying quantitative elasticity in real-time at 2 FPS with an improvement computational time factor of 26. Validation of the system accuracy was conducted on gelatin-based tissue mimicking phantoms, where low bias of elasticity values were reported (4.7%) at low excitation frequencies. Additionally, a new elasticity estimator based on quantitative sonoelastography was developed. A linear problem was modeled from the acquired sonolastography data along the lateral dimension and a regularization method was implemented. The resulting elasticity images presented low bias (1.48%), enhanced CNR and reduced lateral artifacts when evaluating the algorithm’s performance in a breast calibrated phantom and comparing it with other estimators found in the literature. These two contribution benefit the implementation and development of further elastography techniques that could provide enhanced quality of elasticity images and thus, improved accuracy of diagnosis.
Tesis
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Bian, Shuning. "Real-time monitoring of ultrasound and cavitation mediated drug delivery." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:e5a774a9-5b93-4862-8dd9-0614d234ff28.
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Drug delivery plays a crucial role in the chemotherapeutic treatment of cancerous solid tumours. A drug, no matter how potent, is only truly effective when it can be delivered to all targeted cells. In recent years it has been recognised that the poor response of tumours to chemotherapy is in part due to inadequate drug delivery. Numerous strategies have been developed to overcome this issue. Of particular interest to the present work is the application of ultrasound and cavitation, which has been shown to be capable of enhancing drug delivery in solid tumours. These enhancements are attributed to the acoustic cavitation of microbubbles and the effects cavitation induces in the surrounding tissue. To better understand how ultrasound and cavitation can enhance drug delivery, an instrument was developed that is capable of monitoring in real-time and in-situ the effect of ultrasound and cavitation on drugs and drug analogues within flow channel models. The developed instrument was used to investigate the effect of ultrasound and cavitation on drug-eluting beads used for chemoembolisation, the effects of drug loading on microbubble dynamics, the effects produced by different cavitation agents, and the performance of passive acoustic mapping as a means of cavitation monitoring. The findings of the above investigations include: more physiologically relevant characterisations of drug-eluting beads pharmacokinetics, the possibility of significant changes in microbubble dynamics due to drug loading, a lack of general correlation between detected cavitation activity and induced effects, and the potential of passive acoustic mapping for monitoring cavitation and ultrasound induced effects. These and other findings also demonstrate the utility of the developed instrument for studying the many facets and applications of ultrasound and cavitation mediated drug delivery.
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Yuan, Lili. "Feasibility Investigation of Real-time Quantitative Quasi-static Ultrasound Elastography." Digital WPI, 2017. https://digitalcommons.wpi.edu/etd-dissertations/175.
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The individual soft tissues in the human body, such as liver, prostate, thyroid and breast, can each be characterized by a set of mechanical properties. Among these properties, the stiffness, or Young’s modulus, is of particular interest, as disease processes or abnormal growths introduce changes in the tissue stiffness. For example, cirrhosis is associated with an increase in stiffness in the affected region(s) of the liver, and the severity has a strong positive correlation with the measured liver tissue stiffness. Although the conventional ultrasound image is produced by changes in acoustic properties, most notably acoustic impedance (equal to density times sound speed), it is in fact possible to measure tissue strain ultrasonically, by performing ultrasound imaging while the tissue region of interest is mechanically perturbed. Although in principle incorrect, such strain imaging methods are commonly referred to as ultrasound elastography imaging. While tissue strain can reveal the presence of stiffness changes, its diagnostic value is limited due to the inability to reveal the magnitude of the stiffness change. Still, strain imaging is a feature on several commercial scanners. There does in fact exist an elegant, but complex and quite expensive, quantitative ultrasound method of imaging the elasticity of soft tissues, called Supersonic Shear imaging (SSI). However, a much lower cost method of quantitatively imaging tissue elasticity would be useful, especially if the method can be implemented with only minor modifications to existing ultrasound scanner design. This dissertation research deals with an attempt of designing and testing such a method. Ultrasound elastography encompasses a number of diverse techniques, roughly categorized by the mechanical perturbation method into two main groups: quasi-static and dynamic methods. Dynamic elastography requires a vibrating source, either separate or integrated with a transducer, making the imaging system cumbersome, especially for the portable systems. Quasi-static elastography only requires conventional ultrasound hardware, however current techniques remain qualitative with unknown stress distribution. This dissertation focuses on the investigation of free hand quantitative quasi-static elastography, aiming to real time assessment. Our proposed low cost real-time ultrasound elastography system is based on determining an axial strain and an axial stress over a region of interest, i.e., an axial strain image and an axial stress image are required. By taking the axial stress/axial strain ratio for each pixel in the image, an actual elasticity image is established. To achieve this goal, our system needs to ultrasonically measure the mechanical strain fast and accurately over a specified image plane; likewise, the system needs to be able to calculate the mechanical stress over the same image plane in real time. Now, the stress imaging will require us to apply a quasi-static force function and also to be able to quantify this force function. There are two major research efforts we have made to implement a low cost real-time ultrasound elastography system. The first important topic of this dissertation involves the development of a novel displacement and strain estimator based on analytical phase tracking (APT), which has been demonstrated to give better performance in terms of accuracy, resolution and computational efficiency (approximately 40 times faster than the standard time domain cross correlation method). The second important topic is the stress field reconstruction, with efforts in: 1) integrate force sensors into a single linear array transducer probe, with the goal of quantifying the applied force function; 2) propose a superposition method based on Love’s analytical equation to calculate the stress distribution, where this solution is computationally fast enough to allow real time stress field estimation; 3) analyze the accuracy of the proposed stress method using finite element analysis as a reference on different simulated phantoms. The final objective is to combine the strain and stress information together for quantitative elastography. Correspondingly, we have implemented experiments to evaluate the method on homogeneous and inhomogeneous phantoms of various types. Results show that this method is able to distinguish medium with different stiffness. We have conducted experiments to study the feasibility and improve the accuracy of this estimation technique based on phantoms with known elasticity. In principle, such a technique could be used to image the distribution of Young’s modulus under quasi-static compression, with specific applications to medical imaging.
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Xiao, Xu. "Real time motion tracking in image guided focused ultrasound intervention." Thesis, University of Dundee, 2014. https://discovery.dundee.ac.uk/en/studentTheses/09406ccb-bafb-4b44-adcb-20c6cc98caae.
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Focused ultrasound surgery (FUS) or high intensity focused ultrasound (HIFU), is a promising technique for less- or non-invasively destroying unhealthy tissue deep inside the body, without damage to the skin or surrounding tissues. The procedure has been performed under both diagnostic ultrasound and MRI guidance. Treating cancers and metastases in the liver that are unresectable is a potential application for FUS. However the respiratory motion hindered FUS treatment of liver to become a completely non-invasive technique. The method is currently limited to breath-hold treatments under general anaesthesia that is uncomfortable for patients. The purpose of this study is to investigate key issues of US and MRI guided real-time target ablation when the target is in free breathing motion state which is similar to human liver motion. For the ultrasound guided focused ultrasound (USgFUS), diagnostic ultrasound B-mode image was used to track a moving target. The possibility of using strain sonoelastography to assess FUS lesion formation was explored. Multi-layered tissue mimicking phantoms were designed and fabricated to mimic the graphical features of tumours in human livers in diagnostic ultrasound images. The phantom was then fixed onto three motion setups: 1) controllable 1D reciprocal motion stage, 2) controllable 2D reciprocal motion stage, and 3) ventilator driven balloon to mimic breath motion. Active snake tracking was developed to follow the moving phantom to evaluate the tracking accuracy and speed. This method can achieve a speed of 5~6 frames/second with an error less than 1.0 mm. Strain sonoelastography is selected to assess lesion formation for FUS. Through comparisons of the elastograms between pre- and post-FUS around the focal zone, useful information about the FUS-induced lesions could be extracted from the elastographic artefacts. The performance of elastography to assess FUS lesion in egg-white Polyacrylamide (PAA) phantoms and fresh sheep livers was tested. The FUS lesions in the experiment samples (PAA phantoms and fresh sheep livers) were recognizable under strain sonoelastography after image processing. For MRI guided focused ultrasound (MRgFUS), a moving target with similar graphical features of tumours in human liver was tracked via analysing MRI scans. Then letting the ultrasound beam lock onto a moving target was realized via beam-steering by a phased-array HIFU transducer. An MR compatible robotic arm-INNOMOTION was introduced. A fast localization method was developed to make the robotic arm guided HIFU transducer more efficiently. What is more, it becomes a controllable reciprocal moving setup for investigating the raised issues of MRgFUS for motion tracking in this study. Two normal volunteers were scanned via MR scanner. The data was used to 1) design tissue mimicking phantoms with similar graphical features to the volunteer livers, 2) design respiratory motion simulator based on the estimated liver motion parameters, 3) and develop motion tracking algorithm based on the image features of the volunteer livers. The tissue mimicking phantoms appeared to be similar to the structures of volunteer livers in the MR echo planar imaging (EPI) scans. An experiment setup, in which the tissue mimicking phantoms was controlled to move reciprocally, was designed. The off-line MATLAB algorithm based on cross correlation proved to have an acceptable error less than 1.0 mm. A synchronization system between the target motion and beam-steering was built. Several key problems for motion tracking were studied including how to realize beam-steering with a phased-array transducer, how to map target location in the MR frame to the focus position in the transducer frame, and how to use a step-by-step local sonication series to approximate continuous beam-steering. The system’s performance was tested with a series of sonications, in which temperature rises were compared between when the target was moving with and without tracking. A primary conclusion can be made that tracking could decrease the impact of target movement in focused ultrasound ablation. Tracking could be considered as a compensatory method to liver motion caused by respiration during MRgFUS treatment. In conclusion, the thesis proposed a promising research direction to solve the issue of target motion in FUS treatment of human livers and other abdominal organs. The study achieved the target motion tracking both with diagnostic ultrasound and MRI guidance. The focus steering of HIFU transducer was realized accordingly in the MRgFUS, which can allow the focused ultrasound beam to follow a moving target. The strain sonoelastography had proved to become a potential method to assess FUS lesion formation. This study also brings more issues to be solved, e.g. the noise in diagnostic ultrasound during USgFUS tracking, real-time sonoelastography monitoring lesion formation, and new MRI thermometry that is less susceptible to target motion. The real-time image guided FUS would be more promising by overcoming these technical difficulties.
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Hazard, Christopher R. "Real-time three-dimensional ultrasound imaging using synthetic aperture beamforming." The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486399160107451.
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Royer, Lucas. "Real-time tracking of deformable targets in 3D ultrasound sequences." Thesis, Rennes, INSA, 2016. http://www.theses.fr/2016ISAR0017/document.
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De nos jours, les traitements mini-invasifs, tels que l'ablation par radiofréquence, sont de plus en plus utilisés car ils permettent d'éliminer localement les tumeurs à partir de l'insertion d'une aiguille. Cependant, le succès de ces procédures dépend de la précision du positionnement de l'aiguille par rapport aux structures anatomiques. Afin de garantir un placement correct, l'imagerie échographique est souvent utilisée car elle a l'avantage d'être temps-réelle, bas coût, et non-invasive. En revanche, celle modalité peut compliquer la visualisation de certaines structures en raison de sa qualité et de son champ de vue limité. En outre, la précision des interventions peut aussi être perturbée par les déplacements de tissus liés aux mouvements physiologiques du patient et à la manipulation d'instruments médicaux. Afin d'aider le chirurgien à mieux cibler certaines structures anatomiques, de nombreuses équipes de recherche ont proposé des travaux permettant d'estimer la position de régions d'intérêts dans l'imagerie échographique. Cette thèse propose plusieurs contributions permettant de suivre en temps réel des structures déformables dans des séquences d'échographie 3D. Une première contribution repose sur l'utilisation conjointe de l'information visuelle dense et d'une méthode de simulation physique. Dans cette thèse, nous avons aussi proposé un nouveau critère de similarité spécifique à l'imagerie échographique basé sur une étape de détection d'ombres. Enfin, la dernière contribution est liée à une stratégie de suivi hybride permettant d'améliorer la qualité des images. A partir de ces contributions, nous proposons une méthode de suivi robuste au bruit de type« speckle », aux ombres et aux changements d'intensité perturbant l'imagerie échographique. Les performances des différentes contributions sont évaluées à partir de données simulées et de données acquises sur maquettes et sur volontaires humains. Ces résultats montrent que notre méthode est robuste à différents artefacts de l'imagerie échographique. En outre, nous démontrons la performance de notre approche par rapport à différentes méthodes de l'état de l'art sur des bases de données publiques fournies par les challenges MICCAI CLUST'14 et CLUST'15. Dans cette thèse, nous proposons également une application permettant de combiner l'imagerie échographique à l'imagerie par résonance magnétique (IRM). Cette méthode permet d'observer des structures anatomiques non-visibles dans l'imagerie échographique durant l'intervention. Elle est basée sur la combinaison d'une méthode de suivi et d'un recalage multi-modal obtenu à partir d'un système de localisation externe. Cette application a été évaluée sur un volontaire sain à partir d'une plateforme liée au centre Hospitalier Universitaire de RennesNowadays, mini-invasive treatments, such as radio-frequency ablation, are increasingly being used because they allow eliminating tumors locally from needle insertion. However, the success of these therapies depends on the accurate positioning of the needle with respect to anatomical structures. To ensure correct placement, ultrasound (US) imaging is often used since this system has the advantage to be real-time, low-cost, and non-invasive. However, during the intervention, US imaging can complicate the visualization of targeted structures due to its poor quality and its limited field of view. Furthermore, the accuracy of these interventions may also be perturbed by both physiological movements and medical tools displacements that introduce motions of anatomical structures. To help the surgeon to better target malignant tissues, many research teams have proposed different method in order to estimate the position of regions of interest in ultrasound imaging. This thesis provides several contributions that allow tracking deformable structures in 3D ultrasound sequences. We first present a method that allows providing robust estimation of target positions by combining an intensity-based approach and mechanical model simulation. In this thesis, we also propose novel ultrasound-specific similarity criterion based on prior step that aims at detecting shadows. The last contribution is related to a hybrid tracking strategy that allows improving quality of ultrasound images. From these contributions, we propose a tracking method that has the advantage to be invariant to speckle noise, shadowing and intensity changes that can occur in US imaging. The performance and limitations of the proposed contributions are evaluated through simulated data, phantom data, and real-data obtained from different volunteers. Simulation and phantom results show that our method is robust to several artefacts of US imaging such as shadows and speckle decorrelation. Furthermore, we demonstrate that our approach outperforms state-of-the-art methods on the 3D public databases provided by MICCAI CLUST'14 and CLUST'15 challenges. In this thesis, we also propose an application that combines ultrasound imaging to Magnetic Resonance lmaging (MRI). This method allows observing anatomical structures that are not visible in US imaging during the intervention. It is based on the combination between US tracking method and multi modal registration obtained from external localization system. This application was evaluated on a volunteer thanks to an MRJ imaging platform locate at the University Hospital of Rennes
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Roux, Emmanuel. "2D sparse array optimization and operating strategy for real-time 3D ultrasound imaging." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1255/document.
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Aujourd'hui l'utilisation de l'échographie 3D en cardiologie est limitée car l'imagerie de la totalité du myocarde sur un cycle cardiaque, sans apnée, reste un défi technologique. Une solution consiste à réduire le nombre de capteurs dans les sondes échographiques matricielles afin d'alléger le procédé d'acquisition: ces sondes sont dites parcimonieuses. Le but de cette thèse est de proposer les meilleures dispositions d'un nombre réduit de capteurs piézo-électriques répartis sur la surface active de la sonde afin d'optimiser leur capacité à produire des images homogènes en termes de contraste et résolution dans tout le volume d'intérêt. Ce travail présente l'intégration de simulations acoustiques réalistes élaborées au sein d'un processus d'optimisation stochastique (algorithme de recuit simulé). La structure proposée pour le design des sondes parcimonieuse est suffisamment générale pour être appliquée aux sondes régulières (éléments actifs disposés selon une grille) et non-régulières (positionnement arbitraire des éléments actifs). L'introduction d'une fonction d'énergie innovante permet de sculpter en 3D le diagramme optimal de rayonnement de la sonde. Les résultats de sondes optimisées obtenues possèdent 128, 192 ou 256 éléments pour favoriser leur compatibilité avec les échographes commercialisés à ce jour, ce qui permettrait de déployer l'échographie 3D à moindre coût et à très large échelleToday, the use of 3D ultrasound imaging in cardiology is limited because imaging the entire myocardium on a single heartbeat, without apnea, remains a technological challenge. A solution consists in reducing the number of active elements in the 2D ultrasound probes to lighten the acquisition process: this approach leads to sparse arrays. The aim of this thesis is to propose the best configuration of a given number of active elements distributed on the probe active surface in order to maximize their ability to produce images with homogeneous contrast and resolution over the entire volume of interest. This work presents the integration of realistic acoustic simulations performed in a stochastic optimization process (simulated annealing algorithm). The proposed sparse array design framework is general enough to be applied on both on-grid (active elements located on a regular grid) and non-grid (arbitrary positioning of the active elements) arrays. The introduction of an innovative energy function sculpts the optimal 3D beam pattern radiated by the array. The obtained optimized results have 128, 192 or 256 active elements to help their compatibility with currently commercialized ultrasound scanners, potentially allowing a large scale development of 3D ultrasound imaging with low cost systems
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Abbass, Mohamed A. M. S. "Real-time Control of Ultrasound Thermal Ablation using Echo Decorrelation Imaging Feedback." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535468911083998.
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Zhou, Yun. "STUDY OF SINGLE CELL SONOPORATION IN REAL TIME USING ELECTROPHYSIOLOGY TECHNIQUES." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1207251863.
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Ramalli, Alessandro. "Development of novel ultrasound techniques for imaging and elastography : from simulation to real-time implementation." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10050.
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Les techniques ultrasonores offrent de nombreux avantages, à la fois par leur utilisation facile et la sécurité du patient. De plus, la recherche, visant à étendre les possibles champs d’applications, est particulièrement active. Cependant, l’accès à des équipements adaptés et supportant des logiciels est conditio sine qua non pour l’expérimentation de nouvelles techniques. Ce projet de thèse traite des problématiques de traitement du signal et d'image dans un contexte d'imagerie médicale et vise à répondre à deux objectifs scientifiques: le premier consiste à contribuer au développement d'une puissante plateforme de recherche (ULA-OP) alors que le second a pour objectif d'introduire et de valider, grâce à cette plateforme, des méthodes de traitement non-standard qui ne pourraient pas être évaluées avec des équipements médicaux commerciaux. ULA-OP, un équipement recherche qui donne accès aux développeurs à une grande liberté de contrôle et de configuration l’ensemble des parties actives du système, de la transmission aux traitements des signaux échographiques. Il offre aussi la possibilité d’accéder aux signaux bruts à n’importe quel niveau de la chaîne de réception. Durant cette thèse, les capacités du système ont été améliorées en implémentant des outils logiciels comme des simulateurs de champ acoustique (propagation linéaire et non-linéaire), et en développant des programmes de génération de signaux post-échographique. L’ULA-OP a été crucial pour développer et tester différentes techniques non-standard telles qu’un schéma adaptatif de formation de voie et une méthode d’imagerie Doppler couleur/vecteur, qui seront détaillés dans le manuscrit. En particulier, une nouvelle méthode a été développée pour des applications d’élastographie quasi-statique. Cette méthode, basée sur un algorithme d’estimation du mouvement dans le domaine fréquentiel et combinée à une méthode d’imagerie haute fréquence, a permis d’améliorer la qualité des élastogrammes obtenus. Cette nouvelle méthode a d’abord été testée in-vitro par des traitements hors ligne des signaux reçus et pour ensuite être implémentée en temps réel sur le ULA-OP. Les résultats obtenus montrent que cette technique est performante et que les élastogrammes présentent une qualité supérieure comparée à ceux obtenues avec les méthodes connues de la littératureUltrasound techniques offer many advantages, in terms of both ease of realization and patients’ safety. The research aimed at expanding the fields of application, is nowadays particularly active. The availability of suitable hardware and supporting software tools is condicio sine qua non for the experimentation of new techniques. This Ph.D project addresses signal/image processing issues in medical ultrasound and seeks to achieve two major scientific goals: the first is to contribute to the development of a powerful ultrasound research platform (ULA¬OP), while the second is introducing and validating, through this platform, non-standard methods which could not be tested with commercial equipment. ULA-OP is a research system, which gives developers great freedom in terms of management and control of every section, from signal transmission to echo-signal processing; it also offers the possibility to access raw data at any point in the receive chain. During the thesis, the capabilities of the system were improved by creating advanced software tools, such as acoustic field simulators (for linear and nonlinear propagation), and by developing echo-signals post-elaboration programs. ULA-OP was crucial to develop and test various non-standard techniques such as an adaptive beamforming scheme and a color/vector Doppler imaging method, which will be detailed in this thesis. In particular, a novel technique was developed for quasi-static elastography applications. This technique, based on a frequency domain displacement estimation algorithm, combined with a high-frame-rate averaging method, aims at improving the quality of the elastograms. The new method was first tested in-vitro by offline processing the received signals, and then it was implemented in real-time on ULA-OP. The results show that this technique is effective and that the obtained elastograms present higher quality compared with those obtained with standard algorithms
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James, Sheronica L. "Transcranial Ultrasound as a Potential Modality for Real-Time Observation of Brain Motion." Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu1491237629973431.
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Criton, Aline Laure. "An investigation of real time ultrasound Doppler techniques for tissue motion and deformation analysis." Thesis, University of Edinburgh, 2006. http://hdl.handle.net/1842/29080.
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The objective of this dissertation research is to develop new techniques based on Doppler ultrasound to investigate and visualize changes in tissue dynamic and deformation properties due to atherosclerosis in cardiac and vascular applications. A new technique, to correct for the Doppler angle dependency for tissue motion analysis has been developed. It is based on multiple ultrasound beams, and has been validated in vitro to study tissue dynamic properties. It can measure tissue velocity magnitude with low bias (5%) and standard deviation (10%), and tissue velocity orientation with a bias less then 5 degrees and a standard deviation below 5 degrees. A new Doppler based method, called strain rate, has also been developed and validated in vitro for the quantification of regional vessel or myocardial wall deformation. Strain rate is derived from the velocity information and can assess tissue deformation with an accuracy of 5% and a standard deviation less than 10%. Some examples of cardiac strain rate imaging have been gathered and are described in this thesis. Strain rate, as all Doppler based techniques, suffers from angle dependency limitation. A method to estimate one-component strain rate in any direction in the two-dimensional image not necessarily along the ultrasound beam has been developed. The method allows correcting for the strain rate bias along any user-defined direction. In vitro experiments have shown that qualitative two-component strain rate tensor can be derived. Two-component vector velocity from the moving tissue was acquired and two two-component strain rate images were derived. The images showed agreement with the expected deformation pattern.
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Brounstein, Anna B. Marie. "Towards real-time registration of ultrasound and CT in computer aided orthopaedic surgery applications." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/40689.
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Pelvic fractures are serious injuries that are most commonly caused by motor vehicle accidents and affect people of all ages. Surgeries to realign the pelvis and fix the bone fragments with screws have inherent risks and rely on cumbersome intra-operative radioscopic imaging methods. Ultrasound (US) is emerging as a desirable imaging modality to replace fluoroscopy as an intra-operative tool for pelvic fracture surgery because it is safe, portable and inexpensive. Despite the many advantages of US, it suffers from speckle noise, a limited field of view and a low signal-to-noise ratio. Therefore, we must find a way to efficiently process and utilize ultrasound data so that it can be used to effectively visualize bone. In the past decade, there has been much research focused on fusing US with pre-operative Computed Tomography (CT) to be used in an intra-operative guidance system; however, current methods are either too slow or not robust enough to use in a clinical setting. We propose a method to automatically extract bone features in US and CT volumes and register them using a fast point-based method. We use local phase features to estimate the bone surfaces from B-mode US volumes. We simplify the bone surface using particle simulation, which we optimize using the hierarchical Barnes-Hut algorithm. To ensure the point cloud best represents the bone surface, we reinforce them with high curvature features. We then represent the point clouds using Gaussian Mixture Models (GMMs) and find the correspondence between them by minimizing a measure of distance between the GMMs. We have validated our proposed algorithm on a phantom pelvis and clinical data acquired from pelvic fracture patients. We demonstrate a registration runtime of 1.4 seconds and registration error of 0.769 mm.
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Kumssa, Aida Meredassa. "Tablet User Interface Evaluation for a Portable Ultrasound System and Real time Doppler SpectrumProcessing." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-23169.
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In this thesis, real time Doppler spectrum processing and Tablet user interface evaluation for portable ultrasound system is done.In most ultrasound machines, fast fourier transform and other spectral processing requires a specialized hardware, which is costly. In order to have a low cost and portable ultrasound device for application in rural areas, a tablet ultrasound system can be developed. The cost of such a device can be minimized by doing as much real-time processing as possible on the tablet. In the thesis,Doppler spectrum processing and visualization is implemented using various techniques for application on a tablet user interface. The spectral properties are properly designed and the required components of the spectrum rendering window are fully developed. Various user control systems are also developed to allow user interactivity.Tablet user interface evaluation was conducted to assess the usability of the user interface for intended end users (midwives). Before conducting the evaluation, some improvements were performed to the prototype user interface. The usability evaluation of the user interface was conducted by giving usability test task over a group of midwives and evaluated using various usability evaluation methods. By employing these methods, it was possible to measure the typical usability goals such as efficiency, task completion success rate and satisfaction of the users. The analysed results show that all the midwives have achieved high task completion success rate and good task completion time, which is acceptable and most of the users are satisfied with the application.Due to some facility limitations at the beginning of the thesis work, a pilot usability study and its subsequent user interface improvement, which were planned at the beginning, are not included as part of this thesis.
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Chen, Junying, and 陈俊颖. "Design space exploration of real-time bedside and portable medical ultrasound adaptive beamformer acceleration." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B50434354.
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This work explored the design considerations on the real-time medical ultrasound adaptive beamformer implementations using different computing platforms: CPU, GPU and FPGA. Adaptive beamforming has been well considered as an advanced solution for improving the image quality of medical ultrasound imaging machines. Although it provides promising improvements in lateral resolution, image contrast and imaging penetration depth, the use of adaptive beamforming is substantially more computationally demanding than conventional delay-and-sum beamformers. In order not to compromise the real-time performance of medical ultrasound systems, an accelerated solution is desirable.
In this work, CPU implementation was used as a baseline implementation, based on which the intrinsic characteristics of the algorithm were analyzed. After the analysis of a particular adaptive beamforming algorithm, minimum-variance adaptive beamforming, two design parameters M and L were found to affect the implementation performance in two aspects: computational demand and image quality. The trends of the two aspects were contradictory with respect to the increment of M and L values. In our experiments, when M and L increased, the computational demand increased in a cubic curve; meanwhile, the image quality did not have much improvement when the increased values of M and L entered certain ranges. Since we targeted at a real-time solution without sacrificing the good image quality that adaptive beamforming proposed, a tradeoff was made on the selection of M and L values to balance the two contradictory requirements.
Built upon the theoretical algorithmic analysis of the real-time adaptive beamformer realization, the implementations were developed with FPGA and GPU. While a dedicated hardware solution might be able to address the computational demand of the particular design, the need for an efficient algorithm exploration framework demanded a reprogrammable platform solution that was high-performance and easily reconfigurable. Besides, although a simple processor could provide convenient algorithm exploration via software development environment, real-time performance was usually not achievable. As a result, a reprogrammable medical ultrasound research platform for investigating advanced imaging algorithms was constructed in our project. The use of FPGA and GPU for implementing the real-time adaptive beamformer on our platform was explored. In our test cases, both FPGA- and GPUbased solutions achieved real-time throughput exceeding 80 frames-per-second, and over 38x improvement when compared to our baseline CPU implementation.
Moreover, the implementations were also evaluated in terms of portability, data accuracy, programmability, and system integration. Due to its high power consumption, high-performance GPU solution is best suited for bedside applications, while FPGAs are more suitable for portable and hand-held medical ultrasound machines. Besides, while the development time on GPU platform remains much lower than its FPGA counterpart, the FPGA solution is effective in providing the necessary I/O bandwidth to enable an end-to-end real-time reconfigurable medical ultrasound image formation system.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
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Apostolopoulos, Vasileios. "Real time intraoperative three dimensional ultrasound in biopsy and resection of intrinsic brain tumours." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/24922.
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There is growing evidence that maximal surgical resection of malignant gliomas is beneficial, both by increasing the progression free survival (Stummer, Pichlmeier et al. 2006) and also by facilitating postoperative chemotherapy and radiotherapy (Stupp, Mason et al. 2005). In this context there has been an increased need for real time intraoperative imaging in brain tumour surgery. The complex theatre arrangements, prohibitive cost and prolonged theatre time has restricted the wide application of intraoperative MRI (iMRI). Modern intraoperative ultrasound, which in the past has been relatively underused in oncological neurosurgery, is affordable, and easy to use (Unsgaard, Ommedal et al. 2002), but has not been robustly validated. This study attempts to histologically validate the accuracy of the intraoperative US and to explore its potential as an intraoperative navigation tool, which can accurately guide biopsies and resections of intrinsic brain tumours. The digital data extracted from US images obtained during ultrasound guided biopsies was correlated with the histology of the relevant specimens. Image analysis of selected regions of interest (ROI) was employed to extract quantitative parameters from the digital ultrasound images. The mean pixel brightness (MPB) and the standard deviation (SD) were correlated with histological parameters. The pattern of histograms from the selected ROIs was observed and correlated with the histological findings. A close correlation was observed between mean pixel brightness (MPB), an objective measure of echogenicity, and cellularity and an equally close correlation between the standard deviation (SD) and the intrinsic cellular diversity of the analysed areas. These two together, despite not being specific, can indirectly suggest the nature of the tumour and also reflect the sensitivity of intraoperative US to detect the presence and the extent of intrinsic brain tumours. Our findings could have translational potential as an intraoperative guidance tool.
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Castle, Bruce M. "The role of real-time ultrasound in the assessment and management of preterm labour." Doctoral thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/26624.
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In this thesis the use of real-time ultrasound in the assessment and management of preterm labour has been studied, with particular reference to the observation of fetal breathing movements, gross fetal body movements and the state of the uterine cervix. In addition, a longitudinal analysis of the trends in preterm labour in the John Radcliffe Hospital in Oxford between 1973 and 1981 has been performed. Finally, an attempt has been made to clarify the relationship between prostaglandin E2 and fetal breathing movements. The analysis of the trends in preterm labour in Oxford has shown that the incidence of preterm delivery remains unaltered. Of these patients, however, those eligible for tocolytic therapy (unexplained spontaneous preterm labour) form a small proportion. The incidence of extreme prematurity in this group is very low and the neonatal outcome is good. The presence or absence of Fetal Breathing Movements (FBM) by defined criteria is shown to be a highly sensitive index of whether the preterm labour is going to progress to delivery or not in singleton pregnancies with intact membranes. Its significance is lost when the membranes are ruptured and in multiple pregnancies. In pregnancies complicated by antepartum haemorrhage the presence or absence of Fetal Breathing Movements does not predict further haemorrhage leading to delivery. Fetal Breathing Movement status on admission bears no relationship to neonatal outcome and gives no indication of the presence of intrauterine infection. Silent chorioamnionitis has been highlighted as an important cause of "unexplained" preterm labour. Gross Fetal Body Movements (FM) are shown to give no early indication of impending preterm delivery. Evidence is presented to suggest that significant diminution in Fetal Movements is related to poor neonatal outcome. Ultrasonic measurement of the uterine cervix has been found to be technically feasible but of no benefit in the diagnosis of ongoing preterm labour. The relationship between prostaglandin E2 (PGE2) and the cessation of fetal breathing movement has been approached by elucidating the maternal absorption of PGE2 from a vaginal pessary. This then enabled me to sample fetal blood at the time of maximal maternal concentrations (the time we expect the fetal concentration to be greatest). This was performed by fetoscopy and demonstrated that a significant rise in fetal bicycleprostaglandin-E-metabolite (bicyclo-PGEM) occurs following maternal vaginal administration of PGE2. Using this information FBM has been assessed two and a half hours following the vaginal administration of PGE2. Although inconclusive, no reduction in FBM was demonstrated. as the bicyclo-PGE metabolite is used to assess PGE levels, this evidence decreases the probability that PGE mediates the reduction in FBM with the onset of labour.
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Doorbar-Baptist, Stuart. "Physiotherapy Assessment and Management of Post- Prostatectomy Urinary Incontinence." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/15289.
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Aim: To determine the reliability of scoring real-time ultrasound (RTUS) record during an exercise protocol aimed at developing pelvic floor motor control in men with prostate cancer, and to determine predictors of acquiring control. Methods: 91 men diagnosed with prostate cancer attending physiotherapy for pelvic floor exercises. Detailed pelvic floor motor control exercises were taught by a physiotherapist to participants using trans-abdominal RTUS for biofeedback. A new protocol to measure skill attainment was developed. Three independent physiotherapists assessed skill attainment by viewing RTUS videos of the exercise. Reliability was evaluated using intraclass correlation coefficients. Logistic regression analysis was conducted to identify predictors of successful skill attainment. Acquisition of the skill was compared between pre and post-operative participants using an independent-groups t-test. Results: There was good reliability for scoring the outcome method (ICC 0.73 (95%CI 0.59 - 0.82)) for experienced therapists. Having low BMI and being seen pre- operatively predicted motor skill attainment, accounting for 46.3% of the variance. Significantly more patients trained pre-operatively acquired the skill of pelvic floor control compared with patients initially seen post-operatively (OR 11.87 95%CI 1.4 to 99.5 p = 0.02). Conclusions: A new protocol to evaluate attainment of pelvic floor control in men with prostate cancer can be scored reliably from RTUS record, and is most effective delivered pre-operatively. Future Studies: Based on the above research a proposed RCT has been
developed comparing current standard pelvic floor training protocols with a motor control led training protocol. This protocol is followed by development into a progressive resistance program that utilises progressively incremental intra- abdominal pressures as a resistance tool. Further discussion is made to evaluate optimal pelvic floor rehabilitative strategies.
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Zhu, Mengchen. "Real-time B-mode ultrasound image simulation and artifacts modelling of needles and brachytherapy seeds." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/12611.
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The training of ultrasound guided interventional procedures could benefit from ultrasound simulators that synthesize realistic-looking B-mode images of tissue and interventional tools, such as the needle. For a prostate brachytherapy simulator in particular, both the needle and seed images need to be synthesized.
In this thesis, we propose an interpolation-based method for simulating needle and seed B-mode images in real time. We parametrize a needle or a seed B-mode image as a function of its position and orientation. We collect needle and seed images under various spatial configurations in a water-tank using a needle guidance robot. Then we use multi-dimensional tensor-product interpolation to simulate images of needles and seeds with arbitrary poses and positions using collected images. After further processing, the interpolated needle and seed images are superimposed on top of phantom or tissue image backgrounds. The similarity between the simulated and the real images is measured using a correlation metric. The results are also compared to in vivo images. Images in both the transverse and the sagittal planes are simulated.
Artifacts associated with the needle and seed are studied in detail by experiments and by physical models. It is demonstrated that the bright band pattern associated with the sagittal needle images could be interpreted using a plate reflection model; the bright tails associated with the transverse needle images could be analyzed by simulating the back-scattered stress field from a sphere.
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Schlindwein, Fernando Soares. "Real-time digital processing of Doppler ultrasound signals and its application to blood flow measurement." Thesis, University of Leicester, 1990. http://hdl.handle.net/2381/34225.
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A system comprising of a personal microcomputer and a Digital Signal Processor board has been assembled and programmed for real-time spectral analysis of Doppler ultrasound signals. Three spectrum analysis techniques were implemented to run in real-time on the system: The fast Fourier transform (FFT), the autoregressive (AR) model, and the moving average (MA) model. The FFT and the AR techniques were investigated in some depth. The advantages of using such a system are that it is entirely programmable, cheap, reliable, and that the processed information can be stored on diskettes. The inputs to the system are the forward and reverse components of the Doppler ultrasonic signal, and the outputs are the sonogram, the frequency envelope, and the intensity weighted mean frequency curve, which are presented on the screen and can be saved to diskette. Five frequency ranges can be selected by the operator, from 1.28 kHz to 20.48 kHz, corresponding to sampling frequencies from 2.56 kHz to 40.96 kHz. Most commercial systems for real-time spectral analysis of Doppler ultrasonic signals implement the modified FFT-periodogram technique for power spectral density estimation (PSDE), which is computationally very efficient but has some shortcomings, especially for the analysis of relatively short records. With the AR model approach the spectra can be estimated from short segments, no antileakage window is necessary and the spectral resolution is better than for the FFT. A study of some methods for order selection used with the autoregressive model for the spectrum analysis of Doppler signals is reported and the use of a fixed order of around 12 is suggested for the AR model. The implementation of the AR PSDE approach in real-time, in a reasonably priced system, is a step towards the practical use of the so called 'modern techniques' for spectral analysis of Doppler ultrasonic signals, but further work has to be done on the validation of the technique in clinical usage.
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Browne, Jacinta. "Diagnostic ultrasound real-time and colour Doppler imaging assessed by in-vivo and in-vitro methods." Thesis, University of Glasgow, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272856.
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Mozaffari, Maaref Mohammad Hamed. "A Real-Time and Automatic Ultrasound-Enhanced Multimodal Second Language Training System: A Deep Learning Approach." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40477.
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The critical role of language pronunciation in communicative competence is significant, especially for second language learners. Despite renewed awareness of the importance of articulation, it remains a challenge for instructors to handle the pronunciation needs of language learners. There are relatively scarce pedagogical tools for pronunciation teaching and learning, such as inefficient, traditional pronunciation instructions like listening and repeating. Recently, electronic visual feedback (EVF) systems (e.g., medical ultrasound imaging) have been exploited in new approaches in such a way that they could be effectively incorporated in a range of teaching and learning contexts. Evaluation of ultrasound-enhanced methods for pronunciation training, such as multimodal methods, has asserted that visualizing articulator’s system as biofeedback to language learners might improve the efficiency of articulation learning. Despite the recent successful usage of multimodal techniques for pronunciation training, manual works and human manipulation are inevitable in many stages of those systems. Furthermore, recognizing tongue shape in noisy and low-contrast ultrasound images is a challenging job, especially for non-expert users in real-time applications. On the other hand, our user study revealed that users could not perceive the placement of their tongue inside the mouth comfortably just by watching pre-recorded videos.
Machine learning is a subset of Artificial Intelligence (AI), where machines can learn by experiencing and acquiring skills without human involvement. Inspired by the functionality of the human brain, deep artificial neural networks learn from large amounts of data to perform a task repeatedly. Deep learning-based methods in many computer vision tasks have emerged as the dominant paradigm in recent years. Deep learning methods are powerful in automatic learning of a new job, while unlike traditional image processing methods, they are capable of dealing with many challenges such as object occlusion, transformation variant, and background artifacts. In this dissertation, we implemented a guided language pronunciation training system, benefits from the strengths of deep learning techniques. Our modular system attempts to provide a fully automatic and real-time language pronunciation training tool using ultrasound-enhanced augmented reality. Qualitatively and quantitatively assessments indicate an exceptional performance for our system in terms of flexibility, generalization, robustness, and autonomy outperformed previous techniques. Using our ultrasound-enhanced system, a language learner can observe her/his tongue movements during real-time speech, superimposed on her/his face automatically.
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Uhercik, Marian. "Surgical tools localization in 3D ultrasound images." Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00735702.
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This thesis deals with automatic localization of thin surgical tools such as needles or electrodes in 3D ultrasound images. The precise and reliable localization is important for medical interventions such as needle biopsy or electrode insertion into tissue. The reader is introduced to basics of medical ultrasound (US) imaging. The state of the art localization methods are reviewed in the work. Many methods such as Hough transform (HT) or Parallel Integral Projection (PIP) are based on projections. As the existing PIP implementations are relatively slow, we suggest an acceleration by using a multiresolution approach. We propose to use model fitting approach which uses randomized sample consensus (RANSAC) and local optimization. It is a fast method suitable for real-time use and it is robust with respect to the presence of other high-intensity structures in the background. We propose two new shape and appearance models of tool in 3D US images. Tool localization can be improved by exploiting its tubularity. We propose a tool model which uses line filtering and we incorporated it into the model fitting scheme. The robustness of such localization algorithm is improved at the expense of additional time for pre-processing. The real-time localization using the shape model is demonstrated by implementation on the 3D US scanner Ultrasonix RP. All proposed methods were tested on simulated data, phantom US data (a replacement for a tissue) and real tissue US data of breast with biopsy needle. The proposed methods had comparable accuracy and the lower number of failures than the state of the art projection based methods.
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Law, Yuen Verfasser], Torsten [Akademischer Betreuer] [Kuhlen, and Stéphane [Akademischer Betreuer] Cotin. "Real-time simulation of B-mode ultrasound images for medical training / Yuen Law ; Torsten Kuhlen, Stéphane Cotin." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1130792757/34.
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Marshall, Thomas. "Instrumentation for the control of the formation of industrial particulate mixtures, and their real-time monitoring by ultrasound." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311819.
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Sihono, Dwi Seno Kuncoro [Verfasser], and Frederik [Akademischer Betreuer] Wenz. "Real-Time Ultrasound Image-Guidance and Tracking in External Beam Radiotherapy / Dwi Seno Kuncoro Sihono ; Betreuer: Frederik Wenz." Heidelberg : Universitätsbibliothek Heidelberg, 2020. http://d-nb.info/1204637644/34.
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Vidal, Franck P. "Simulation of image guided needle puncture : contribution to real-time ultrasound and fluoroscopic rendering, and volume haptic rendering." Thesis, Bangor University, 2008. https://research.bangor.ac.uk/portal/en/theses/simulation-of-image-guided-needle-puncture-contribution-to-realtime-ultrasound-and-fluoroscopic-rendering-and-volume-haptic-rendering(6b916772-c962-44c5-aea7-158ae948ff2a).html.
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The potential for the use of computer graphics in medicine has been well established. An important emerging area is the provision of training tools for interventional radiology (IR) procedures. These are minimally invasive, targeted treatments performed using imaging for guidance. Training of the skills required in IR is an apprenticeship which still consists of close supervision using the model i) see one, ii) do one and iii) teach one. Simulations of guidewire and catheter insertion for IR are already commercially available. However, training of needle guidance using ultrasound (US), fluoroscopic or computed tomography (CT) images - the first step in approximately half of all IR procedures - has been largely overlooked and we have developed a simulator, called BIGNePSi, to provide training for this commonly performed procedure. This thesis is devoted to the development of novel techniques to provide an integrated visual-haptic system for the simulation of US guided needle puncture using patient specific data with 3D textures and volume haptics. The result is the realization of a cost effective training tool, using off-the-shelf components (visual displays, haptic devices and working stations), that delivers a high fidelity training experience. We demonstrate that the proxy-based haptic rendering method can be extended to use volumetric data so that the trainee can feel underlying structures, such as ribs and bones, whilst scanning the surface of the body with a virtual US transducer. A volume haptic model is also proposed that implements an effective model of needle puncture that can be modulated by using actual force measurements. A method of approximating US-like images from CT data sets is also described. We also demonstrate how to exploit today's graphics cards to achieve physically-based simulation of x-ray images using GPU programming and 3D texture hardware. We also demonstrate how to use GPU programming to modify, at interactive framerates, the content of 3D textures to include the needle shaft and also to artificially add a tissue lesion into the dataset of a specific patient. This enables the clinician to provide students with a wide variety of training scenarios. Validation of the simulator is critical to its eventual uptake in a training curriculum and a project such as this cannot be undertaken without close co-operation with the domain experts. Hence this project has been undertaken within a multi-disciplinary collaboration involving practising interventional radiologists and computer scientists of the Collaborators in Radiological Interventional Virtual Environments (CRaIVE) consortium. The cognitive task analysis (CTA) for freehand US guided biopsy performed by our psychologist partners has been extensively used to guide the design of the simulator. In addition, to ensure that the fidelity of the simulator is at an acceptable level, clinical validation of the system's content has been carried out at each development stage. In further, objective evaluations, questionnaires were developed to evaluate the features and the performances of the simulator. These were distributed to trainees and experts at different workshops. Many suggestions for improvements were collected and subsequently integrated into the simulator.
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Bouscher, Robert F. "Advancements in Powder Coating Processing and in Real-time Film Formation Analysis of Thermoset Coatings." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1627566578541715.
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Kumar, Hemant, University of Western Sydney, and of Science Technology and Environment College. "Software analytical tool for assessing cardiac blood flow parameters." THESIS_FSTA_XXX_Kumar_H.xml, 2001. http://handle.uws.edu.au:8081/1959.7/392.
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Introduction of Doppler ultrasound techniques into the Intensive Care setting has revolutionised the way haemodynamic status is monitored in the critically ill. However, in order to increase the usefulness of these techniques, the Doppler signal and its spectrum need to be further analysed in ways to facilitate a better clinical response. Extensive processing of the Doppler spectrum on Diagnostic ultrasound machines is limited by the real time performance considerations. It was therefore proposed that the spectral information from these systems be extracted off-line and full set of analytical tools be made available to evaluate this information. This was achieved by creating an integrated and modular software tool called Spectron, which was intended as an aid in the overall management of the patients. The modular nature of Spectron was intended to ensure that new analytical tools and techniques could be easily added and tested. The software provides its users with considerable latitude in choosing various data acquisition and analysis parameters to suit various clinical situations and patient requirements. Spectron was developed under the Windows environment to provide a user friendly interface and to address a range of programming problems such as memory management and the size of the colour palettes. Spectron is able to detect the maximal velocities and compute the mean and median velocities. Relative increases in maximal velocities in cardiac blood flows after the administration of inotropic drugs have been shown in the pilot studies that were conducted. Spectron is able to help in obtaining estimates of the aortic blood flows and in other applications such measuring vascular impedance. Stenotic blood flows can be detected by using the spectral broadening index and blood flow characteristics can be studied by using various blood flow indices. Thus, this project attempted to help in patient management by providing clinicians with a range of blood flow parameters and has succeeded in meeting its objective to a large extentMaster of Engineering (Hons)
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Kramar, Johanna. "Prostate brachytherapy: Pre-plan and real-time transperineal ultrasound guided Iodine-125 permanent seed implants at Södersjukhuset, Karolinska University Hospital." Thesis, Stockholm University, Medical Radiation Physics (together with KI), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8299.
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Purpose: The aim of this thesis is to study the European (ESTRO/EAU/EORTC) and American (ABS) guidelines how to report the permanent seed implant and the most significant dosimetric parameters. It will also report on the permanent seed implant at Södersjukhuset, Karolinska University Hospital according to the guidelines. A large number of studies on pre- and post-implant dosimetry on permanent seed implants have recently been published but none is considered a standard. This makes it difficult, if not impossible, to compare data from different centres. The differences in reporting will also be discussed in this thesis. Another part of the study is to investigate how the morbidity correlates with the dose. The results in this report will give an overview of the experience at Södersjukhuset.
Matherials and Methods: This study includes 198 patients who received implants between 2004-2007 with I-125 seeds under transperineal ultrasound at Södersjukhuset (to a prescribed dose of 145 Gy). The dose-planning system VariSeed 7.1 was used with an online connection to the ultrasound system with real-time verification. Dose constraints for the planning system are V(100)>99%, V(150)>60%, V(200)>25%, UrD(10)<130% and UrD(30)<125%. Outer and inner wall of rectum was outlined for 55 patients as recommended by ESTRO/EAU/EORTC and doses to rectum were also computed.
Results: The median value for dosimetric parameters at Södersjukhuset, Karolinska University Hospital are for the prostate; D(90)=174Gy (153-194Gy), V(100)= 99% (93-100%), V(150)= 57% (40-74%), for the urethra; UrD(30) = 130% (112-147%), UrD(10) = 124% (107-142%) and for the rectum; RD2cc= 98Gy (73-128Gy), RD0.1cc=164Gy (119-240Gy), RV(100)=0.3cc (0.0-1.3cc), RV(150)=0.0cc (0.0-0.2cc). These values correspond to recommended data, except for the V(150) value. Regarding the clinically observed results, 3 patients had a relapse in their cancer, 2 patients had mild proctitis and 15 patients had urinary problems.
Discussion and Conclusions: The significant dosimetric parameters for reporting according to ESTRO/EAU/EORTC and ABS for prostate are D90[Gy], V(100)[%] and V(150)[%], for urethra are D(30) and D(10), and for rectum RD2cc and RD0.1cc. These parameters consider as a minimum to use and they further recommend secondary parameters to report. Other authors have also recommended to report RV(100) and RV(150) for rectum. This study did not show any relationship between UrD(10), UrD(30) and urinary morbidity. According to the recommendations every patient should undergo a CT-based evaluation. Further investigations are needed on whether a post-implant CT-study is necessary for real-time implantation, as there is not enough published data on this aspect.
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Schulte, zu Berge Christian Ulrich [Verfasser], Nassir [Akademischer Betreuer] [Gutachter] Navab, and Bernhard [Gutachter] Preim. "Real-time Processing for Advanced Ultrasound Visualization / Christian Ulrich Schulte zu Berge ; Gutachter: Nassir Navab, Bernhard Preim ; Betreuer: Nassir Navab." München : Universitätsbibliothek der TU München, 2016. http://d-nb.info/1116604302/34.
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Ipsen, Svenja [Verfasser], Achim [Akademischer Betreuer] Schweikard, and Heinz [Akademischer Betreuer] Handels. "See what you treat : 4D ultrasound imaging for real-time motion compensation in the liver / Svenja Ipsen ; Akademische Betreuer: Achim Schweikard, Heinz Handels." Lübeck : Zentrale Hochschulbibliothek Lübeck, 2020. http://d-nb.info/1215719760/34.
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Roxburgh, Zoe. "Visualising articulation : real-time ultrasound visual biofeedback and visual articulatory models and their use in treating speech sound disorders associated with submucous cleft palate." Thesis, Queen Margaret University, 2018. https://eresearch.qmu.ac.uk/handle/20.500.12289/8899.
Full textAbstract:
Background: Ultrasound Tongue Imaging (UTI) is growing increasingly popular for assessing and treating Speech Sound Disorders (SSDs) and has more recently been used to qualitatively investigate compensatory articulations in speakers with cleft palate (CP). However, its therapeutic application for speakers with CP remains to be tested. A different set of developments, Visual Articulatory Models (VAMs), provide an offline dynamic model with context for lingual patterns. However, unlike UTI, they do not provide real-time biofeedback. Commercially available VAMs, such as Speech Trainer 3D, are available on iDevices, yet their clinical application remains to be tested. Aims: This thesis aims to test the diagnostic use of ultrasound, and investigate the effectiveness of both UTI and VAMs for the treatment of SSDs associated with submucous cleft palate (SMCP). Method: Using a single-subject multiple baseline design, two males with repaired SMCP, Andrew (aged 9;2) and Craig (aged 6;2), received six assessment sessions and two blocks of therapy, following a motor-based therapy approach, using VAMs and UTI. Three methods were used to measure therapy outcomes. Firstly, percent target consonant correct scores, derived from phonetic transcriptions provide outcomes comparable to those used in typical practice. Secondly, a multiplephonetically trained listener perceptual evaluation, using a two-alternative multiple forced choice design, to measure listener agreement provides a more objective measure. Thirdly, articulatory analysis, using qualitative and quantitative measures provides an additional perspective able to reveal covert errors. Results and Conclusions: There was overall improvement in the speech for both speakers, with a greater rate of change in therapy block one (VAMs) and listener agreement in the perceptual evaluation. Articulatory analysis supplemented phonetic transcriptions and detected covert articulations and covert contrast as well as supporting the improvements in auditory outcome scores. Both VAMs and UTI show promise as a clinical tool for the treatment of SSDs associated with CP.
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Olmo, Osuna Cristian. "Ultrasound micromolding technique and real-time X-ray diffraction using synchrotron radiation : applications to porous scaffolds for biomedical devices and study of thermal-induced transitions." Doctoral thesis, Universitat Politècnica de Catalunya, 2021. http://hdl.handle.net/10803/672329.
Full textAbstract:
Current market trend is moving to miniaturized specimens, especially in the biomedical field seeking high effective and less invasive treatrnent. Ultrasound (US) micromolding is a new technique developed to the aim of producing microsized pieces based on the use of ultrasound waves as a heating source. This heating method is highly precise and can lead to produce microsized pieces with high energy and material efficiencies by using short cycling times compared to other conventional techniques.
This PhD work explores further possibilities of ultrasound micromolding to the production of polymers with added value. The work is divided in two main blocks: the production of micropieces based on biodegradable polymers focused on biomedical applications and the application of this technique as a new method to obtain nanocomposites with a homogenous dispersion ofthe reinforcing material.
Polylactide (PLA) was selected as polymer matrix in the first block to produce drug loaded pieces and scaffolds with antibacterial activity or increased osteoconductivity by the incorporation of hydroxyapatite (HAp). Chlorhexidine (CHX) and triclosan (TCS), selected as representative bactericide agents, were successfully loaded with a homogenous distribution into the polymer matrix Drugs were slowly released from micropieces and presented clear bactericide and bacteriostatic effect against both Gram-positive and Gram-negative bacteria. Microporous scaffolds have been produced from the subsequent leaching of incorporated salts. By using NaCI cavitation problems could be avoided but pores interconnections were insufficient anda small amount of water soluble polymer (i.e. polyethylene glycol) was required in order to improve the leaching process. Final scaffolds showed enhanced cell proliferation compared to non-porous PLA PLNHAp scaffolds with a porosity degree close to 35% could be achieved with relatively good mechanical properties. lncorporation of HAp increased the thermal stability, hydrophilicity and cell proliferation with respect to neat PLA specimens.
Ultrasound waves are usuallycombined with the conventional method to produce nanocomposite (i.e. solution intercalation and melt mixing) to avoid nanoparticles aggregation and improve their distribution within the polymer matrix Hence the second block ofthis PhD work studies the use of ultrasound micromolding technology in nanocomposites production. To this end, Polycaprolactone and polyamide 12 were selected as polymer matrices whereas multi-walled carbon nanotubes
(MWCNT) and Nanofil 757 (a non-organo modified clay) were chosen as reinforcing agent. Both neat polymers and their nanocom posites were successfully micromolded with minimal polymer degradation under optimal molding condition (amplitude, force and time). US micromolding technique was revealed to be efficient in getting fully exfoliated nanocomposites even when Nanofil 757 was selected. Moreover, the influence of both, MWCNTand Nanofil 757, on crystallization behaviorand morphology were systematically studied by time resolved synchrotron experiments. Crystalline polymorphic transitions of nylon 12 were also evaluated through analyses of real time synchrotron.
A final chapter of this thesis is devoted to the study of structural transitions of nylons 12 9, 8 9, 4 9, 4 5 and copolymers derived from 1,4-diam inobutane and different ratios of glutaric and azelaic acids (nylon 4, 5+9) in order to achieve deeper knowledge on the series of even-odd polyam ides. These polyamides show different crystalline structure and structural transitions compared to the conventional polyamides, which root cause is still unclear.El uso de piezas de tamaño reducido se ha extendido en los últimos años como sinónimo de evolución tecnológica, especialmente en biomedicina, donde se están realizando grandes avances con el fin de mejorar la eficiencia de los tratamientos terapéuticos y aumentar el uso de procedimientos menos invasivos. El micromoldeo por ultrasonidos (USM) es una novedosa técnica para la obtención de micropiezas caracterizada por el uso de ultrasonidos como fuente de calor; gracias a este sistema calefacción el USM presenta tiempos de ciclo extremadamente cortos y un alto rendimiento energético. El trabajo expuesto en esta tesis doctoral se divide en dos partes, un primer bloque enfocado en explorar posibles aplicaciones biomédicas de micropiezas basadas en polímeros biodegradables y un segundo bloque en el que se estudia la posibilidad del uso de dicha técnica para la preparación de nanocompuestos. La polilactida (PLA) fue seleccionada como polímero biodegradable en el primer bloque para la producción de micropiezas cargadas con fármacos y scaffolds con actividad antibacteriana o reforzada con hidroxiapatita (HAp) para incrementar su osteoconductividad. Como agentes bactericidas se escogieron clorhexidina (CHX) y triclosan (TCS), los cuales se cargaron con éxito en la matriz de PLA presentando una distribución uniforme y una clara actividad antibacteriana. Los scaffolds porosos se prepararon por un proceso indirecto al remover la sal soluble en agua tras ser moldeada junto al polímero. Aunque era factible obtener piezas de PLA cargadas con NaCI sin problemas de cavitación o degradación del polímero la conexión entre los poros era insuficiente y una gran cantidad de sal quedaba retenida en la pieza final. Con tal de incrementar dicha interconexión y conseguir un scaffolds poroso libre de NaCI fue necesario agregar polietilenglicol (PEG). Los scaffolds finales cargados con TCS presentan una mejora en la proliferación celular, un efecto bactericida y bacteriostático y una liberación más rápida. En los sistemas PLA/HAp fue crítico el uso HAp libre de impurezas para evitar cavitaciones yamarilleamiento en las muestras. La incorporación de HAp mejoró la estabilidad térmica, la hidrofobicidad y la proliferación y colonización celular. Los procesos convencionales para la producción de nanocompuestos (preparación por disolución y mezclado en fundido) suelen usar ondas de ultrasonidos para mejorar el proceso y evitar la aglomeración de las nanopartículas, aumentando así las interacciones refuerzo-polímero. Con esta premisa en mente el segundo bloque de esta tesis abarca la producción, mediante USM de dos tipos de nanocom puestos: una matriz de policaprolactona (PCL) con nanotubos de carbono (MWCNT) y una matriz de poliamida 12 (Nylon 12) con arcilla. El USM es un proceso adecuado para la obtención de nanocompuestos exfoliados en un solo paso, incluso cuando la arcilla utilizada no ha sido modificada orgánicamente (N757). La influencia de ambos agentes externos (MWCNT y N757) en el proceso de cristalización y la morfología cristalina se han estudiado mediante e>IJ) erimentos de sincrotrón en tiempo real. Las transiciones polimórficas del nylon 12 también fueron estudiadas mediante los datos recopilados en los experimentos con radiación sincrotrón. En un último bloque se han estudiado también las estructuras y transiciones estructurales de los nylons 12 9, 8 9, 4 9, 4 5, así como varias copoliamides derivadas de la 1,4-butanodiamina y distintas proporciones de ácidos glutárico y azelaico (nylon 4,5+9) mediante datos calorimétricos, espectrocópicos y de difracción de rayos X recogidos en barridos de calentamiento y enfriamiento . Estas poliamidas tipo par-impar muestran estructuras peculiares y unas transiciones estructurales diferentes a las de otras poliamidas convencionales y cuyo origen aún no está claro.
Polímers i biopolímers
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Almeida, Isabel Carolina de Carvalho Bastos de. "Perfomance do transverso do abdómen : recurso à ecografia como informação de retorno extrínseca." Master's thesis, Faculdade de Ciências Médicas. Universidade Nova de Lisboa, 2011. http://hdl.handle.net/10362/6326.
Full textAbstract:
RESUMO: Desenho do estudo: Estudo quantitativo, experimental prospectivo de factor único, desenho pré-teste, pós-teste.
Objectivos: Determinar a efectividade da ecografia em tempo real, como Informação de
Retorno Extrínseca Visual Ecográfica (IRE-VE) na performance do transverso do abdómen (TrA), em sujeitos saudáveis; analisar eventuais diferenças entre a IRE-VE e a Informação de Retorno Extrínseca Verbal Clínica (IRE-VC); medir a performance da musculatura abdominal, através das diferenças na espessura dos músculos TrA e oblíquo interno (OI) e deslizamento do TrA, em repouso e em contracção.
Enquadramento: A maioria dos indivíduos não tem conhecimentos nem consciência do
contributo de uma boa performance do TrA para a estabilidade da coluna lombar. Vários
estudos recentes se têm dedicado a este assunto, tendo sido mostrado o importante contributo da ecografia como Informação de Retorno Extrínseca (IRE). Uma vez que o TrA e o OI contribuem para a estabilidade lombo pélvica, e que a aprendizagem do seu controlo motor é essencial para a recuperação da função, torna-se relevante clarificar o contributo da informação de retorno na primeira fase da aprendizagem da performance desses músculos, bem como encontrar as melhores estratégias para a sua realização. A ecografia foi o instrumento escolhido para servir esse objectivo.
Métodos: Participaram no estudo 75 sujeitos, sem queixas lombares, com idades compreendidas entre os 18 e os 38 anos com um valor médio de 21,9 anos (±4,03), divididos aleatoriamente em três grupos com uma tarefa comum: a “Manobra do Transverso”, em que um grupo não recebeu IRE (GC), outro recebeu IRE verbal clínica e palpatória (GIRE-VC) e ooutro recebeu IRE visual ecográfica (GIRE-VE). Para efeitos de análise da contracção da musculatura abdominal, foram estudadas a espessura dos músculos TrA e OI e o deslizamento do TrA, visualizados em imagens ecográficas em tempo real, e congeladas para medição em diferido. Estes procedimentos foram apurados num estudo piloto de fidedignidade das medições em causa. Quanto à abordagem estatística das variáveis de performance muscular foi realizada uma análise da variância simples paramétrica para amostras independentes e um teste para a diferença de médias para amostras emparelhadas.
Resultados: Observamos que no GC, a ausência de IRE cursou com uma performance
idêntica nos dois momentos de avaliação e que nos dois grupos com IRE, das variáveis de
performance, é significativamente diferente a contracção do TrA, para uma diferença de 1,95 mm no GIRE-VE (p=0,000) e de 0,84 mm no GIRE-VC (p=0,000). Ao comparar os grupos
entre si houve diferenças no limiar da significância (p=0,056) para uma melhor contracção do TrA no GIRE-VE. As outras variáveis, contracção do OI e deslizamento do TrA, não revelaram efeito relacionado com a IRE em nenhum dos grupos.
Conclusão: Dos resultados obtidos, podemos concluir que a IRE-VE, quando usada
isoladamente, na Manobra do Transverso provoca um maior aumento na espessura do TrA,
quando comparada com a IRE-VC . O uso da ecografia mostrou ser efectivo na facilitação da performance da Manobra do Transverso em sujeitos saudáveis.---------------------ABSTRACT: Study Design: Single Factor Experimental Design: Pre-Test Post-test Control Group Design.
Objectives: To measure the contribution of different types of biofeedack on Transversus
Abdominis (TrA) and Internal Oblique (IO) performance through changes in thickness and
lateral slide of TrA anterior fascia during abdominal hollowing exercise (AHE).
Background: Increasingly clinicians are using real-time ultrasound imaging as a form of
supplementing feedback when teaching trunk stabilization exercises to patients; however,
there has been no evidence of its effectiveness when used alone.
Material and Methods: Seventy-five healthy subjects were divided randomly into 3 groups
that received: group 1, no feedback; group 2, verbal and palpatory feedback, and group 3, realtime ultrasound feedback. The TrA and IO performance of each subject was twice assessed (before and after receiving feedback) when performing the AHE in a supine hook-lying position. Analysis of variance and T-test were used for the independent and paired samples,
respectively, to determine significant changes in the performance of TrA and IO, based on intra and inter group analysis.
Results: Group 1 had no differences between moments; group 2 had significant differences
concerning TrA thickness (p=0,000) to a 0,84 mm thickness difference; group 3 had significant differences concerning TrA thickness (p=0,000) to a 1,94 mm difference; The ability to perform the AHE differed only among group 3 and group 1 (p=0.056), and only for changes in thickness of TrA muscle. No differences among groups were found neither for the lateral slide of TrA
anterior fascia, nor for the internal oblique thickness. Conclusion: From the results of this study we conclude that real-time ultrasound feedback,
when used alone during an AHE, can have a larger increase in TrA thickness when compared to verbal and palpatory feedback.
The use of real time ultrasound showed to be effective as a feedback tool to facilitate the performance of the AHE in a supine hook-lying position in healthy subjects.
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Kumar, Hemant. "Software analytical tool for assessing cardiac blood flow parameters." Thesis, View thesis, 2001. http://handle.uws.edu.au:8081/1959.7/392.
Full textAbstract:
Introduction of Doppler ultrasound techniques into the Intensive Care setting has revolutionised the way haemodynamic status is monitored in the critically ill. However, in order to increase the usefulness of these techniques, the Doppler signal and its spectrum need to be further analysed in ways to facilitate a better clinical response. Extensive processing of the Doppler spectrum on Diagnostic ultrasound machines is limited by the real time performance considerations. It was therefore proposed that the spectral information from these systems be extracted off-line and full set of analytical tools be made available to evaluate this information. This was achieved by creating an integrated and modular software tool called Spectron, which was intended as an aid in the overall management of the patients. The modular nature of Spectron was intended to ensure that new analytical tools and techniques could be easily added and tested. The software provides its users with considerable latitude in choosing various data acquisition and analysis parameters to suit various clinical situations and patient requirements. Spectron was developed under the Windows environment to provide a user friendly interface and to address a range of programming problems such as memory management and the size of the colour palettes. Spectron is able to detect the maximal velocities and compute the mean and median velocities. Relative increases in maximal velocities in cardiac blood flows after the administration of inotropic drugs have been shown in the pilot studies that were conducted. Spectron is able to help in obtaining estimates of the aortic blood flows and in other applications such measuring vascular impedance. Stenotic blood flows can be detected by using the spectral broadening index and blood flow characteristics can be studied by using various blood flow indices. Thus, this project attempted to help in patient management by providing clinicians with a range of blood flow parameters and has succeeded in meeting its objective to a large extent
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Kummer-Hannoun, Pascale. "Etude d'un imageur echographique en temps reel et comparaison avec une technique d'ouverture synthetique pour le controle industriel." Paris 6, 1987. http://www.theses.fr/1987PA066460.
Full textAbstract:
Nous avons realise un systeme d'imagerie ultrasonore, en temps reel, a partir d'un reseau lineaire, afin d'examiner des fissures dans des pieces metalliques massives. Etude comparative entre la technique d'imagerie classique semblable a l'echographie medicale, (deja appliquee au controle non destructif), et la technique d'ouverture synthetique connue en c. N. D. : au vu des images obtenues avec les deux techniques a partir d'informations provenant d'une meme cible, il est clair que l'apodisation est a l'avantage de l'imagerie classique; et l'amelioration de la resolution laterale en ouverture synthetique n'est pas assez significative pour qu'un projet en temps reel, electroniquement tres complexe, soit retenu. Enfin, en ce qui concerne l'echographe, la modelisation du comportement theorique du reseau a permis une bonne prediction des resultats experimentaux. Ses performances, evaluees pour des applications industrielles typiques sont comparables a celles du systeme allemand "holosaft" qui utilise la reconstruction d'ouverture synthetique lente efficacement
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Gomes, Rui Pedro Lebreiro. "Fine-Grained localization system for indoor environments." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13534.
Full textAbstract:
Mestrado em Engenharia Electrónica e de TelecomunicaçõesThe increasing demand for tracking solutions in indoor environments has led to the development of many indoor location systems based in the most diverse technologies. They are trying to fill a market niche left by the current available location systems such as the well-known Global Positioning System (GPS). These systems are limited to an outdoor usage due to the drastic attenuation of the GPS signals in closed areas and they cannot provide enough resolution to meet the requirements of certain applications. Therefore, it’s here proposed the conception of a system capable of locating a mobile module in indoor environments with an accuracy of a few centimeters. The system’s concept is based in measuring the time difference of arrival (TDOA) between a radio frequency signal and an ultrasonic burst in order to measure distances. The huge difference between the propagation velocities of RF waves comparatively to sound waves allows the system to accurately measure the time difference between the two arrivals and use that value to estimate the distance that separates the source from the destination. This document describes the development of all the necessary hardware for the conception of a final prototype and all the aspects regarding the software implementation. This system is composed by two types of devices that can be divided in Ultrasonic (US) transmitters and receivers. Each device is equipped with a RF module that allows them to communicate through a wireless network based in the IEEE802.15.4 protocol. In the end, a functional prototype was achieved that was subsequently submitted to several tests in order to evaluate its performance. These tests corroborated the viability of this localization method with the prototype achieving a remarkable precision level.
A crescente demanda por soluções de rastreamento em ambientes interiores levou ao desenvolvimento de vários sistemas de localização baseados nas mais diversas tecnologias. Eles vêm tentar colmatar um nicho de mercado deixado pelos sistemas de localização actualmente disponíveis como o caso do bem conhecido Sistema de Posicionamento Global (GPS). Estes sistemas estão limitados ao uso exterior devido à drástica atenuação dos sinais GPS em áreas fechadas e eles não oferecem resolução suficiente para cumprir os requisitos de certas aplicações. Por conseguinte, é aqui proposta a concepção de um sistema capaz de localizar um módulo móvel em ambientes interiores com uma resolução de alguns centímetros. O conceito do sistema é baseado na medição da diferença dos tempos de chegada entre um sinal de radiofrequência e um sinal de ultra-sons de forma a calcular distâncias. A enorme diferença entre as velocidades de propagação das ondas RF comparativamente às ondas sonoras permitem ao sistema medir com precisão a diferença entre o tempo de chegada dos dois sinais e usar esse valor para estimar a distância que separa a fonte do destino. Este documento descreve o desenvolvimento de todo o hardware necessário para a concepção de um protótipo bem como todos os aspectos relativos à implementação de software. Este sistema é composto por dois tipos de dispositivos que podem ser divididos em transmissores e receptores de sinais ultrassónicos. Cada dispositivo está equipado com um módulo de radiofrequência que lhes permite comunicar através de uma rede sem fios baseada no protocolo IEEE802.15.4. No final, foi alcançado um protótipo funcional que posteriormente foi submetido a vários testes de forma a avaliar o seu desempenho. Estes testes vieram corroborar a viabilidade deste método de localização com o protótipo a atingir um notável nível de precisão.
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Aguilar, Beltran Luis Alberto. "Towards Real-time Simulation of Ultrasound Systems." Thesis, 2012. http://hdl.handle.net/1807/33899.
Full textAbstract:
Diagnostic ultrasound is a non-invasive image modality commonly used to diagnose multiple diseases. Sonographers and physicians have to devote a substantial amount of time learning how the combination of the various parameters of the ultrasound system affects the resulting ultrasound information among its different modalities. The primary objective of this thesis is to create a mechanistic ultrasound simulation method that could achieve near real-time performance to teach and train sonographers and physicians. A major bottleneck for achieving real-time performance with available tools was the transducer field simulation method that uses the impulse response technique. To address this problem a new simulation approach was developed. This project was realized in a three-phase approach, specifically to simulate spectral Doppler. In first place, it was shown that is possible to mechanistically simulate the sample volume power distribution using a novel method based on an array of point sources to represent the transducer geometry. Secondly, by comparison with the Field II results, it was demonstrated that the time-domain signal could be closely reproduced using point sources. Finally, by treating the array of point sources as point receivers, the received signal was compared with the results from Field II, and again, good agreement was achieved. Simulation results were compared against the standard simulation method for a number of examples involving steady and pulsatile flow, for which the spectrograms were compared against Field II. Also presented are preliminary results obtained using the point source approach to simulate B-mode images. As well, methods are described for generating Doppler spectrograms from the results of computation fluid dynamics velocity fields obtained in realistic arterial geometrical models. It is pointed out that the successful simulation of the time domain signal opens the possibility for real-time simulation of other ultrasound modes.
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"Real-time three-dimensional ultrasound in obstetric application." Thesis, 2010. http://library.cuhk.edu.hk/record=b6075051.
Full textAbstract:
Conotruncal anomalies are the leading causes of cyanotic congenital heart disease. We attempted to use live xPlane imaging of ductal arch view and in-plane view of IVS to screen the fetal conotruncal anomalies in 200 fetuses. There were 152 normal cases, 25 conotruncal anomalies and 23 other types of fetal CHDs were involved in this study. The visualization rate of the normal ductal arch view and in-plane view of IVS with live xPlane imaging was 100% (152/152), 100% (152/152) in normal cases, 8% (2/25), 12% (3/25) in conotruncal anomalies and 69.7% (16/23), 73.9% (17/23) in non-conotruncal CHDs, respectively. The visualization rate of abnormal ductal arch and in-plane view in conotruncal anomalies was much higher than that in non-conotruncal anomalies (P<0.001). Therefore, it may be a useful tool for the assessment and diagnosis of fetal conotruncal anomalies.In conclusion, real-time 3DE is a novel and promising technique to perform the prenatal examination, both the fetal heart and other system. It represents the future of 3D ultrasound and will become a useful tool for prenatal screening and diagnosis.
This thesis summarized real-time 3D ultrasound in obstetric application. With the introduction of matrix transducer, 3D scanning the fetus in real time became available.
We attempted to use real-time 3D ultrasound in obstetrics outside the fetal heart. We evaluated the feasibility of using real-time 3D ultrasound to assist in obtaining a true midsagittal view in first trimester. Eight sonographers, including FMF-certified and non FMF-certified operators, were asked to perform ultrasound examinations on five patients and forty patients were examined in total. It showed that the deviation from true midsagittal view was reduced greatly with the guidance of live xPlane imaging. Real-time 3D ultrasound can improve the accuracy of acquisition of a defined sonographic plane, and reduce the difference in performance between operators who are formally certified or not.
We demonstrated a novel method to visualize the aortic and ductal arch with live xPlane imaging. The visualization rate is 100%. Ductal arch view can be visualized by placing the reference line through pulmonary artery and descending aorta and aortic arch view can be acquired by putting the reference line along the transverse view of aortic arch and descending aorta on the 3VT view with live xPlane imaging. Therefore, live xPlane imaging is an easy and feasible method for real-time imaging of the ductal and aortic arch.
We explored the feasibility to perform the fetal heart screening using real-time 3DE with live xPlane imaging. We developed and reported the methodology of acquiring and examining the screening planes of the fetal heart with live xPlane imaging. The procedure was simple and straight. When performing the fetal heart screening with live xPlane imaging, we just need display the apical four-chamber view and mid-sagittal view of fetal upper thorax and other thing could be done by moving the reference line. The overall detection of four cardiac screen planes can reach 100%.
We explored to evaluate the entire fetal IVS with both live xPlane imaging and live 3D imaging. We can successfully assess the entire IVS in most fetuses (153/154). We also compared the images acquired by real-time 3DE and STIC in this thesis. It showed that less motion artifact encounters with real-time 3DE and the image quality of real-time 3DE is similar to STIC volume acquired from the sagittal view (P>0.05) and superior to STIC volume from the four-chamber view (P<0.05). Therefore, real-time 3DE can be used to display the lateral view of the fetal IVS, and potentially may be a useful tool for the assessment and diagnosis of fetal VSDs.
Xiong, Yi.
Adviser: Tzekin Lau.
Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: .
Thesis (Ph.D.)--Chinese University of Hong Kong, 2010.
Includes bibliographical references (leaves 116-138).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
45
Hung, Chieh Ming, and 洪傑銘. "Real-time Ultrasound Nakagami Imaging System: Establishment and Validation." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/67583806798300103375.
Full textAbstract:
碩士長庚大學
醫學影像暨放射科學系
103
Ultrasonic backscattering signals contain valuable information about the scatter properties, such as size, shape, and density. Based on the randomness of backscattering, the Nakagami statistical distribution was widely used to describe the probability density function of the backscattered signals by estimating the Nakagami parameter. It has been shown that ultrasound Nakagami parametric imaging is able to visualize the scatterer properties, and many literatures have demonstrated the performance of Nakagami imaging in tissue characterization. In this study, a real-time Nakagami imaging system for scatterer characterization is established and validated. The phantoms with scatterer concentrations ranged from 1-32 scatterers/mm3 were made to test the performance of real-time Nakagami imaging system, which was based on a portable ultrasound system and a self-designed software platform and algorithms. Moreover, real-time Nakagami imaging system was applied to evaluate the Nakagami parameter of normal liver. The results demonstrated that the Nakagami parameter of phantoms ranged from 0.6-1.1 and the distribution of normal liver between all subjects approached Rayleigh distribution. These results demonstrated that the proposed real-time Nakagami imaging system has the ability to detect the variation in the scatterer concentration. Such an ultrasound parametric imaging system has great potential in future clinical applications for diagnosis liver disease.
46
"Phase Aberration Correction for Real-Time 3D Transcranial Ultrasound Imaging." Diss., 2009. http://hdl.handle.net/10161/1243.
Full text
47
Ivancevich, Nikolas M. "Phase Aberration Correction for Real-Time 3D Transcranial Ultrasound Imaging." Diss., 2009. http://hdl.handle.net/10161/1243.
Full textAbstract:
Phase correction has the potential to increase the image quality of real-time 3D (RT3D) ultrasound, especially for transcranial ultrasound. Such improvement would increase the diagnostic utility of transcranial ultrasound, leading to improvements in stroke diagnosis, treatment, and monitoring. This work describes the implementation of the multi-lag least-squares cross-correlation and partial array speckle brightness methods for static and moving targets and the investigation of contrast-enhanced (CE) RT3D transcranial ultrasound.
The feasibility of using phase aberration correction with 2D arrays and RT3D ultrasound was investigated. Using the multi-lag cross-correlation method on electronic and physical aberrators, we showed the ability of 3D phase aberration correction to increase anechoic cyst identification, image brightness, contrast-to-noise ratio (CNR), and, in 3D color Doppler experiments, the ability to visualize flow. With a physical aberrator, CNR increased by 13%, while the number of detectable cysts increased from 4.3 to 7.7.
We performed an institutional review board (IRB) approved clinical trial to assess the ability of a novel ultrasound technique, namely RT3D CE transcranial ultrasound. Using micro-bubble contrast agent, we scanned 17 healthy volunteers via a single temporal window and 9 via the sub-occipital window and report our detection rates for the major cerebral vessels. In 82% of subjects, we identified the ipsilateral circle of Willis from the temporal window, and in 65% we imaged the entire circle of Willis. From the sub-occipital window, we detected the entire vertebrobasilar circulation in 22% of subjects, and in 50% the basilar artery.
We then compared the performance of the multi-lag cross-correlation method with partial array reference on static and moving targets for an electronic aberrator. After showing that the multi-lag method performs better, we evaluated its performance with a physical aberrator. Using static targets, the correction resulted in an average contrast increase of 22.2%, compared to 13.2% using moving targets. The CNR increased by 20.5% and 12.8%, respectively. Doppler signal strength and number of Doppler voxels increased, by 5.6% and 14.4%, respectively, for the static method, and 9.3% and 4.9% for moving targets.
We performed two successful in vivo aberration corrections. We used this data and measure the isoplanatic patch size to be an average of 10.1°. The number of Doppler voxels increased by 38.6% and 19.2% for the two corrections. In both volunteers, correction enabled the visualization of a vessel not present in the uncorrected volume. These results are promising, and could potentially have a significant impact on public health.
Lastly, we show preliminary work testing the feasibility of a unique portable dedicated transcranial ultrasound system capable of simultaneous scanning from all three acoustic windows. Such a system would ideally be used in a preclinical setting, such as an ambulance.
Dissertation
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Yang, Min-Chun, and 楊閔淳. "Real-Time Fuzzy Tumor Detection for PC-based Breast Ultrasound." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/40687309999898888889.
Full textAbstract:
碩士國立中正大學
資訊工程所
96
In recent year, the portable PC-based US imaging systems developed by some companies can provide an integrated computer environment for the computer-aided diagnosis or detection applications. In this paper, a real-time automatic tumor detection system based on the fuzzy approach using the PC-based system Terason t3000 (Terason Ultrasound, Burlington, MA, USA) is proposed. The system can prompt a real-time alert and show the detected tumor frames for the operator if the suspected tumors are found while scanning the breast. Furthermore, the real-time detection requirement can be met by implementing the multi-threading technique in our proposed system. After applying the fuzzy approach to each overlapped US image, the pixel classification of the US image can be obtained. Then, the connected component labeling and tumor criteria are used to obtain the suspected tumor regions. The spatial relationship of suspected regions of three perpendicular views is calculated and compared, and only the suspected regions exist in at least two views are viewed as the real tumor regions for obtaining a more accurate detection results. In order to validate the feasibility and accuracy of the proposed system, twenty examinations are conducted by scanning the phantom. Moreover, the free-response operative characteristics (FROC) curve is used to evaluate the detection performance of the proposed system. According to the experimental results, the proposed system yields a 90.0% detection sensitivity at a FP rate of 1.55 FP per case; it shows a quite satisfactory detection performance for the real-time detection system.
49
Zahiri-Azar, Reza. "Real-time imaging of elastic properties of soft tissue with ultrasound." Thesis, 2005. http://hdl.handle.net/2429/16987.
Full textAbstract:
Current imaging devices such as computed tomography (CT) , ultrasound (US) and magnetic
resonance imaging (MRI) are not directly capable of measuring the mechanical properties of soft
tissue even though such measurement would have a high clinical demand. Elastography with the
aid of ultrasound has been well established in the literature as a strain imaging technique. Under
certain conditions, these strain images can give a clear illustration of the underlying tissue stiffness
distributions which has been shown to provide useful clinical information. Vibro Elastography is
another new imaging system that performs a transfer function analysis of the tissue motion. The
shape of the transfer function can be analyzed further and the stiffness of tissue can be estimated
from the magnitude of the transfer functions at low-frequencies.
This thesis introduces a fast and accurate motion tracking algorithm which is at the heart of
both strain imaging and stiffness imaging. The algorithm achieves real-time performance (> 20
fps) without any need for additional hardware and its overhead. The performance of the proposed
method is evaluated quantitatively according to its signal-to-noise ratio, contrast-to-noise ratio,
dynamic range, resolution and sensitivity with both simulation data and phantom data. Also,
the computational efficiency of the algorithm is compared with current real-time motion tracking
algorithms. The results show that it is the most time efficient algorithm to date. Furthermore the
performance of the proposed method is evaluated qualitatively from the real-time images that are
generated in both tissue mimicking phantoms and real tissues in vivo.
By using this method two real-time elastography packages have been implemented which can
easily be clinically applied. These implementations run at 35fps for strain images and 2fps for
transfer function images of 16,000 pixels on an Ultrasonix RP500 ultrasound machine.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Lee, Tsung-Yeh, and 李宗燁. "GPU-Based Frequency Domain Beamforming for Real-Time Ultrasound 3D Imaging." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/10900725620902052130.
Full textAbstract:
碩士國立臺灣大學
生醫電子與資訊學研究所
102
Medical ultrasound imaging system is generally used as a diagnosis tool in clinical medicine. For general 2D imaging purpose, the system uses 1D array transducer to transmit/receive RF data, do the delay and sum beamforming (DAS), add some adequate imaging processing techniques, and finally, output the good quality image result in real-time. However, if 1D array transducer is replaced by 2D array for 3D imaging purpose, large RF data size will make the DAS too slow to keep the system real-time. Therefore, this research combines two techniques to speed up beamforming, that is, plane wave frequency domain beamforming (PWFDBF) and parallel programming on GPU. First, PWFDBF can use just one set of RF data to beamform one frame image. This feature will reduce the complexity and processing time of beamforming funamentally and enormously. Second, the powerful parallel processing ability of GPU will make PWFDBF ever faster. Field II is used in this research for creating simulated RF data. Then, Matlab is used for simulating PWFDBF and compounding imaging technique, verifying the correctness of the image result and doing the analytis of image quality. Finally, parallel programming PWFDBF is implemented on the PC with GPU by CUDA programming language. And Nsight is used for speed analysis. According to the experiment result, equivalent frame rate of PWFDBF can reach to the real-time standard(30 frames/s) under the simulated environment which is a 2D array transducer with 64 x 64 channels x 4096 samples. The result proves that the research is indeed a possible solution for 3D ultrasound imaging system according to the final processing time analysis result.