Academic literature on the topic 'Leg Tomography'
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Journal articles on the topic "Leg Tomography"
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Reikerås, Olav, and Arne Høiseth. "Torsion of the leg determined by computed tomography." Acta Orthopaedica Scandinavica 60, no. 3 (January 1989): 330–33. http://dx.doi.org/10.3109/17453678909149288.
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Wilson, Joshua M., R. Edward Coleman, and Timothy G. Turkington. "Variable-time positron emission tomography leg protocol to equalize noise for positron emission tomography/computed tomography acquisitions." Nuclear Medicine Communications 32, no. 9 (September 2011): 868–72. http://dx.doi.org/10.1097/mnm.0b013e328347f1a3.
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Convertino, V. A., D. F. Doerr, J. F. Flores, G. W. Hoffler, and P. Buchanan. "Leg size and muscle functions associated with leg compliance." Journal of Applied Physiology 64, no. 3 (March 1, 1988): 1017–21. http://dx.doi.org/10.1152/jappl.1988.64.3.1017.
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Leg compliance is "causally related with greater susceptibility" to orthostatic stress. Since peak O2 uptake (peak VO2) and muscle strength may be related to leg compliance, we examined the relationships between leg compliance and factors related to muscle size and physical fitness. Ten healthy men, 25-52 yr, underwent tests for determination of vascular compliance of the calf (Whitney mercury strain gauge), peak VO2 (Bruce treadmill), calf muscle strength (Cybex isokinetic dynamometer), body composition (densitometry), and anthropometric measurements of the calf. Cross-sectional areas (CSA) of muscle, fat, and bone in the calf were determined by computed tomography scans. Leg compliance was not significantly correlated with any variables associated with physical fitness per se (peak VO2, calf strength, age, body weight, or composition). Leg compliance correlated with calf CSA (r = -0.72, P less than 0.02) and calculated calf volume (r = -0.67, P less than 0.03). The most dominant contributing factor to the determination of leg compliance was CSA of calf muscle (r = -0.60, P less than 0.06), whereas fat and bone were poor predictors (r = -0.11 and 0.07, respectively). We suggest that leg compliance is less when there is a large muscle mass providing structural support to limit expansion of the veins. This relationship is independent of aerobic and/or strength fitness level of the individual.
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Angelhed, J. E., L. Strid, E. Bergelin, and B. Fagerberg. "Measurement of lower-leg volume change by quantitative computed tomography." Acta Radiologica 49, no. 9 (November 2008): 1024–30. http://dx.doi.org/10.1080/02841850802427879.
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Background: Lower-leg edema is a common symptom in many diseases. A precise method with low variability for measurement of edema is warranted in order to obtain optimal conditions for investigation of treatment effects. Purpose: To evaluate computed tomography for precise measurement of lower-leg muscle and adipose tissue volumes using a very low level of effective radiation dose. Material and Methods: Eleven volunteers were examined three times during 1 day, either as two consecutive examinations in the morning and one single examination in the afternoon, or as one examination in the morning and two in the afternoon. Eleven scans with computed tomography were made at each examination, and lower-leg volumes were calculated from automatically measured scan areas and interscan distances. Volumes for muscle, adipose tissue, and bone were calculated separately. Minimal radiation dose was used. Results: Mean difference between the repeated examinations was −0.1 ml for total volume, −1.4 ml for muscle, and 1.6 ml for adipose tissue volume. The corresponding 95% confidence intervals were −6.5 to 6.0 ml, −3.5 to 6.5 ml, and −7.0 to 4.0 ml, respectively. The resulting effective dose was 0.5 µSv to one leg. Conclusion: Computed tomography can be used as a precise quantitative method to measure small volume changes of the lower leg as a whole, and separately for muscle and adipose tissue. The results were obtained with a negligible effective dose, lower than that delivered by modern fan-beam dual-energy X-ray absorptiometry whole-body examinations and equal to a few hours of background radiation.
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Harris, Ian, Angela Hatfield, and Judie Walton. "ASSESSING LEG LENGTH DISCREPANCY AFTER FEMORAL FRACTURE: CLINICAL EXAMINATION OR COMPUTED TOMOGRAPHY?" ANZ Journal of Surgery 75, no. 5 (May 2005): 319–21. http://dx.doi.org/10.1111/j.1445-2197.2005.03349.x.
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Subramaniam, Sriram. "The SIV Surface Spike Imaged by Electron Tomography: One Leg or Three?" PLoS Pathogens 2, no. 8 (August 25, 2006): e91. http://dx.doi.org/10.1371/journal.ppat.0020091.
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Buda, S., D. Gronemeyer, H. M. Hafez, M. Matzke, A. Walter, and K. D. Budras. "Computed Tomography as a New Tool for Investigating Leg Weakness in Turkeys." Anatomia, Histologia, Embryologia: Journal of Veterinary Medicine Series C 34, s1 (December 2005): 9. http://dx.doi.org/10.1111/j.1439-0264.2005.00669_19.x.
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Pavlovic, Mladen, Bojan Milosevic, Dragce Radovanovic, Aleksandar Cvetkovic, Bratislav Trifunovic, Dragan Canovic, Slobodanka Mitrovic, et al. "Malignant fibrous histiocytoma of the right upper leg: A case report." Vojnosanitetski pregled 75, no. 3 (2018): 320–25. http://dx.doi.org/10.2298/vsp160512237p.
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Introduction. Malignant fibrous histiocytoma is a fast spreading pleomorphic sarcoma with a high malignant potential. Its spreading is characterized with local invasion and distant metastazes with early onset. Most common localisations of development are extremities, trunk and retroperitoneum. Given the line of rare case and specimen, lack of a clear etiology and mechanisms of this disease, as well as adequate histopathologic findings and intraoperative documentation, we presented current status, discuss putative etiology, histopathology with variant morphology, differential diagnosis and treatment modalities. Case report. We presented a 56-years-old female Serbian with tumor in the thigh that clinically resembles incapsulated hematoma. Computed tomography revealed intramuscular tumor with a heterodense structure and compression on surround tissue. Ex tempore biopsy specimen showed malignant potential of the tumor. Wide and radical excision of the nodule has been done, and definitive histopathological verification revealed malignant fibrous histiocytoma. Conclusion. Malignant fibrous histiocytoma is a most common type of soft tissue sarcomas in adults. Frequent localization is on lower extremities, and every rapidly enlarging nodule in this localization that on computed tomography is like incapsulated hematoma with necrotic zone should alert suspicion on presence of this type of sarcoma.
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Holme, Thomas J., Johann Henckel, Kai Hartshorn, Justin P. Cobb, and Alister J. Hart. "Computed tomography scanogram compared to long leg radiograph for determining axial knee alignment." Acta Orthopaedica 86, no. 4 (January 13, 2015): 440–43. http://dx.doi.org/10.3109/17453674.2014.1003488.
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Makrogiannis, Sokratis, Fatima Boukari, and Luigi Ferrucci. "Automated skeletal tissue quantification in the lower leg using peripheral quantitative computed tomography." Physiological Measurement 39, no. 3 (April 3, 2018): 035011. http://dx.doi.org/10.1088/1361-6579/aaafb5.
Full textDissertations / Theses on the topic "Leg Tomography"
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Philippe, Julien. "Développement d'une presse portative pour les études in et ex situ sous conditions extrêmes de pression, température et déformation." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066008.
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Les hautes pressions sont précieuses à plusieurs disciplines scientifiques. Ce sera le cas dans cette thèse avec le développement d'un nouvel appareil permettant des possibilités inédites de tomographie et de déformation sous haute pression et haute température. Il apporte la possibilité de nouvelles études scientifiques dans les différents champs disciplinaires que sont les sciences de la Terre, la chimie mécanique, la physique des matériaux et la physique des liquidesHigh pressures are essential in several scientific field. This will be the case in this thesis with the development of a new device enabling new possibilities tomography and deformation under high pressure and high temperature. It brings the possibility of further scientific studies in the various disciplines that are Earth science, mechanical chemistry, physics of materials and liquids physics
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Boutet, Jérôme. "Localisation d'inclusions fluorescentes dans les milieux diffusants à l'aide de techniques laser. Application au diagnostic médical in vivo." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENY009/document.
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La tomographie de fluorescence est une méthode d'imagerie préclinique et clinique permettant de localiser des traceurs fluorescents préalablement injectés ou naturellement présents dans un organisme vivant. Ce travail de thèse à consisté, dans un premier temps, à définir l'architecture et les conditions d'utilisation optimales d'un tomographe de fluorescence continu appliqué à l'observation de tissus de faible épaisseur. On s'est en particulier attaché à traiter le problème de l'observation de tissus hétérogènes et d'organes fortement absorbants. Dans un deuxième temps, pour observer des tissus de plus grande épaisseur, nous avons montré l'apport de la mesure du temps de vol moyen des photons pour améliorer la localisation d'inclusions fluorescentes. Les performances de deux types de systèmes capables de réaliser ce type de mesure ont été comparées et nous avons proposé un protocole permettant d'en optimiser les principaux paramètres. Notre procédé a été appliqué à la problématique du guidage de biopsies prostatiques. Il pourra aussi être utilisé pour visualiser d'autres pathologies moyennant une simple adaptationFluorescence tomography is a preclinical and clinical imaging method which aims to localize fluorescent probes injected into a living organism. In this thesis work, we defined the optimal design and parameters of a continuous wave fluorescent tomograph applied to thin tissue observation. We handled the problem of observing heterogeneous and highly absorbing organs. Secondly, we showed the advantage of time of flight measurement for inclusion detection through thicker tissues. The detection performances of two types of system capable of these measurements were compared and we proposed a protocol to optimize their main parameters. This process was applied to the problematic of prostatic biopsy guiding. It would also be used to detect and localize other pathologies by means of a simple adaptation
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Krasnoshlyk, Victoria. "Etude multi-échelles et multiphysiques des mécanismes de fissuration dans les matériaux à base de fibres naturelles." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI028/document.
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L’utilisation des matériaux constitués de fibres synthétique ou naturelle est en pleine expansion et concerne de nombreux secteurs : industrie automobile, aéronautique, électrique, filtration de l’air ou applications médicales. Malgré des procédés de fabrication et des natures de fibres différents, ces matériaux ont pour point commun d’être constitués d’un réseau de fibres liées entre elles par des liaisons. Les papiers et les cartons sont, par exemple, constitués de fibres de cellulose naturelles liées chimiquement. A l’heure actuelle, les mécanismes de fissuration dans de tels milieux sont encore mal compris. Ils dépendent fortement (a) des propriétés des constituants : géométrie et propriétés mécaniques des fibres et des contacts fibre-fibre, (b) des caractéristiques des réseaux fibreux : géométrie et arrangement des fibres, et des caractéristiques du réseau poreux induit : porosité, distribution de taille des pores, répartition spatiale des pores, etc. et (c) des modes de sollicitations mécaniques. Dans ce type de matériaux, les effets d’échelles doivent être pris en compte pour compléter les approches mécaniques traditionnelles. Les récents progrès en mécanique expérimentale et en simulation numérique permettent de mener une telle étude de l’échelle de la fibre à celle du réseau fibreux.Cette thèse a donc pour but de mettre en place des outils d’analyse des microstructures et des mécanismes de fissuration dans les milieux fibreux à faible densité. Pour cela, (i) des essais de micromécaniques seront couplés à des méthodes d’imagerie (ESEM, microtomographie à rayons X, stéréocorrélation) afin de caractériser expérimentalement les milieux et leur endommagement (ii) Cette étude vient compléter les travaux expérimentaux menés dans les deux laboratoires 3SR et LGP2 (ANR ANAFIB http://anafib.hmg.inpg.fr/spip.php?rubrique1) et sera complétée par des simulations numériques des essais réalisés en collaboration avec Per Isaksson de l’Université d’Uppsala (Suède)Materials made up of synthetic or natural fibres are increasingly developed in various domains: papermaking, composite, automotive and aeronautic industries for structural, packaging, air filtration or medical applications. Despite the variety of manufacturing processes of such materials, all of them can be considered as being formed by a network of fibres interconnected via bonds. For instance, in the case of materials made up of natural cellulosic fibres such as papers or boards, fibres are chemically linked.Crack propagation phenomena in such materials remain poorly understood even though it can be presumed that such mechanisms depend on:- (i) the geometrical and mechanical properties of the constituents of individual fibres and fibre-fibre bonds,- (ii) the architecture of the fibrous network, for example the spatial distributions of fibres, bonds and pores and the size distributions of pores and bonds,- (iii) the applied mechanical loadings.In such materials, scale effects must be investigated in order to improve the classical approaches used to understand crack propagation mechanisms. Recent progresses in both experimental mechanics and numerical simulation approaches allow such a study from the fibre scale up to the fibre network scale to be carried out.The proposed PhD aims first at developing an original experimental approach to analyse microstructure changes and crack propagation phenomena for low density papers. For that purpose x-ray microtomography or ESEM, and stereo-correlation experiments will be carried out to investigate microstructural changes and deformation mechanisms at all relevant scales (see the illustration given in )
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Potin, Bertrand. "Les Alpes occidentales : tomographie, localisation de séismes et topographie du Moho." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAU022/document.
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Les Alpes occidentales, résultat de la collision entre la plaque Eurasie et le promontoire apulien de la plaque Afrique, traversent l'Europe sur près de 1200 km. C'est l'une des chaînes de montagnes les mieux étudiées au monde, notamment par des méthodes d'imagerie géophysique. Celles-ci ont permis de réaliser plusieurs grands profils d'échelle crustale par sismique active. Parallèlement, la sismicité de magnitude relativement modérée a motivé le déploiement de réseaux sismologiques denses permettant de localiser plusieurs milliers d'évènements par an. Ces données apportent énormément d'information sur la géodynamique actuelle des Alpes et ont servi à réaliser plusieurs tomographies. L'ensemble de ces travaux permet une bonne compréhension de la chaîne, cependant des incertitudes persistent motivant la présente étude dont l'ambition est de réaliser une tomographie de la lithosphère des Alpes occidentales.Notre étude s'appuie sur plus de 791000 temps d'arrivée d'ondes P et S émises par plus de 36000 séismes locaux et enregistrées par 375 stations. Le domaine d'étude de 456x414 km2 couvre le sud-est de la France, le nord-ouest de l'Italie et la majeure partie de la Suisse. Dans ce domaine, la majorité des séismes a lieu dans les premiers 15 km de la croûte et grande partie des temps d'arrivée correspondent à des ondes réfractées au toit du manteau. Cela permet d'obtenir une résolution convenable à la fois dans la croûte et dans le toit du manteau. L'intérêt d'utiliser un grand nombre de données est double : cela assure une couverture relativement complète du domaine et améliore par la loi des grands nombres la précision du modèle déterminé. Toutefois, ce type de jeu de données nécessite un traitement adapté pour gérer les inévitables données aberrantes.La tomographie par temps d'arrivée de séismes locaux de la lithosphère a été réalisée à l'aide du code INSIGHT, développé au cours de cette étude à partir d'un code de V. Monteiller et B. Valette. Le modèle est constitué des valeurs de vP et vP/vS en chaque nœud d'une grille 3D à taille de maille constante, des localisations et des paramètres d'effets de site analogues aux « corrections statiques » de la prospection sismique. Le modèle vP a priori pour la croûte et le manteau supérieur est une fonction continue de la profondeur. Les localisations initiales des foyers ont été obtenues à l'aide du code LOCIN développé pour cette étude et permettant de déterminer une densité de probabilité par recherche sur grille. Les temps de propagation sont déterminés pour les premières arrivées en intégrant la lenteur le long des rais ; la géométrie de ceux-ci est déterminée par le maximum du gradient des temps de propagation, eux-mêmes calculés par la résolution de l'équation eikonale par différences finies. L'inversion est menée par une approche de moindres carrés non-linéaires, basée sur une description stochastique des données et des paramètres du modèle.La topographie du Moho est déduite de ce modèle de tomographie en prenant le maximum du gradient de vP obtenu entre les isovitesses 7,3 et 7,6 km/s. Cette information est complétée par des modèles issus de précédentes études. La large proportion d'ondes réfractées de notre lot de données permet un niveau de détails relativement fin. Ce modèle du Moho est ensuite introduit comme interface a priori dans un nouveau processus de tomographie dans lequel les paramètres vP et vP/vS de la croûte et du manteau sont décorrélés. La discontinuité du Moho est mieux modélisée et les ondes réfractées sont mieux déterminées. Cette approche permet par ailleurs de calculer les temps de propagation des ondes directes lorsque celles-ci arrivent après les ondes réfractées : plus de 100000 temps d'arrivées sont ainsi ajoutés aux données et la résolution dans la croûte est améliorée.Ces deux tomographies, la topographie du Moho et les localisations fines apportent de nouvelles informations sur les structures profondes des Alpes occidentalesThe Alpine chain, which stretches in the middle of Europe across six countries, is probably the most studied mountain range in the world. Geology and metamorphism studies contributed for a large part to the current understanding of the geodynamics and history of this region. Since the second half of the 20th century, geophysical methods were employed to study its lithosphere and several crustal cross-sections where performed, mainly using controlled-source seismology. In parallel, dense seismic networks were also deployed in France, Italy, and Switzerland in order to study the usually low-magnitude activity of the western Alps. Over the past 25 years, these networks have permitted to locate tens of thousands of local earthquakes. In the last two decades, local or regional tomographic studies have been conducted using subsets of this data, which substantially improved our understanding of the deep structure of the Alps.Here, and based on 36,000 seismic events, 375 stations and more than 791,000 P and S-waves arrival times, we performed a tomographic study on a 456x414 km2 area covering the western Alps. Even if most of these earthquakes occurred within the first 15 km beneath surface, a large part of the data is composed of refracted-waves, letting us insight the deep structure of the crust. The interest of such a large dataset relies on the accuracy ensured by the law of large numbers, but the unavoidable presence of outliers requires a specific approach in order to handle it. The a priori earthquake locations were computed using the LOCIN algorithm developed in this study, which is basically a grid-search algorithm combined with a probabilistic approach.Tomography of the crust and upper mantle based on travel-times analysis was conducted using the INSIGHT algorithm which was developed in this study (based on a V. Monteiller and B. Valette algorithm). Our model consists of a set of vP and vP/vS values given at each node of a three-dimensional, regularly-spaced grid, which constitutes the inversion grid. Transition between crust and mantle is modelled by a continuous change in velocity, as we do not introduce any a priori information on the Moho interface. Earthquake locations and site-effect residuals at each station (analogous to "static corrections" in seismic prospecting) are also determined in the process. The forward computation of travel times in the 3D model is performed by integrating slowness along the rays, which are determined by a finite-difference resolution of the eikonal equation. Inversion is carried out using a non-linear least-squares approach based on a stochastic description of data and model. The smoothing and damping parameters are adjusted by means of L-curves analysis.The Moho topography is determined by matching two informations: (i) the maximum of the vP gradient within this preliminary tomographic model, taken in a 7.3-7.6~km/s range and (ii) information provided by previous studies to fix Moho depth in the border area of our study zone, where our model is poorly resolved. As our tomographic model relies on a large set of refracted waves, the Moho topography we build is detailed and presents interesting new insights for the western Alps. This Moho interface is then used as an a priori discontinuity in a new tomography process. Parameters within the crust and the upper mantle are then decorrelated, letting refracted-waves to be more correctly modelled. By this approach, we are able to compute not only the first- but also the second-arrival travel-time which corresponds to the direct wave in the crust for focus-station distances greater than 100-125 km. This allows us to add more than 100,000 new data to our dataset, which of course improves the resolution in the crust.Both tomographic models, the Moho topography and the earthquake relocations provides new evidences and constraints on the deep structure of the western Alps
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Flores, Jiménez Alejandro. "Atmospheric Tomography Using Satellite Radio Signals." Doctoral thesis, Universitat Politècnica de Catalunya, 2000. http://hdl.handle.net/10803/6881.
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Los sistemas de posicionamiento global GNSS (GPS y GLONASS) se han convertido en una herramienta básica para obtener medidas geodésicas de la Tierra y en una fuente de datos para el estudio atmosférico. Proporcionan cobertura global y permanente y por la precisión, exactitud y densidad de datos, las señales radio transmitidas pueden ser usadas para la representación espacio-temporal de la atmósfera.La tecnología de los receptores GPS ha evolucionado con una sorprendente rapidez, resultando en instrumentos con suficiente calidad de medida para ser utilizados en estudios geodésicos, comparables a los resultados de técnicas como la interferometría de muy larga base (VLBI), y estudios atmosféricos cuyos resultados pueden ser usados en meteorología.
En la tesis Tomografía Atmosférica utilizando Señales Radio de Satélites nos hemos centrado en el uso del sistema GPS por disponer mayor cantidad y calidad de referencias y herramientas para el procesado de los datos. No obstante, se ha demostrado la posibilidad de extender el concepto a cualquier sistema de transmisión radio desde satélite como sondeador atmosférico. La estructura de la tesis se ha dividido en dos áreas: el procesado de datos GPS para extraer información referente a los parámetros atmosféricos de interés, y la aplicación de técnicas tomográficas para la resolución de problemas inversos. En particular, la tomografía se ha aplicado a la ionosfera y la atmósfera neutra. En ambos casos, los resultados tienen un innegable impacto socio-económico: a) la monitorización del estado ionosférico es fundamental por las perturbaciones que la ionosfera provoca en las transmisiones radio que la atraviesan, y b) la estimación del contenido de vapor de agua de la troposfera es de utilidad en la predicción meteorológica y climática.
La tomografía ionosférica se empezó a desarrollar usando únicamente datos de la red global IGS. A continuación se mejoró la resolución vertical mediante la utilización de datos de ocultaciones del experimento GPS/MET. La mejora de la resolución se ve limitada a la región en la que estos datos existen. Finalmente, se utilizaron datos de altimetría del satélite TOPEX/POSEIDON para mejorar los mapas y para demostrar la posibilidad de calibración instrumental de los altímetros radar usando técnicas tomográficas.
La aplicación a la troposfera se obtuvo tras la mejora y refinamiento tanto del procesado de datos GPS como del proceso de inversión tomográfica. Los primeros resultados se obtuvieron mediante los datos experimentales de la red permanente en Kilauea, Hawaii, por la configuración particular de los receptores. Estos resultados demostraban la capacidad de obtener representaciones espacio-temporales de la troposfera mediante datos GPS. El análisis de los datos de la campaña REGINA, realizada en el Onsala Space Observatory, nos permitió la descripción de un fenómeno meteorológico complejo mediante la tomografía troposférica usando datos GPS y su verificación por comparación directa con medidas realizadas por radiosondeo.
En conclusión, se ha demostrado la posibilidad de aplicar tomografía a la atmósfera utilizando señales radio de satélites y, en particular, la constelación GPS.
The Global Navigation Satellite Systems (GPS and GLONASS) have become a basic tool to obtain geodetic measurements of the Earth and a source of data for the atmospheric analysis. Since these systems provide a global, dense and permanent coverage with precise and accurate data, the radio signals they transmit can be used for the spatio-temporal representation of the atmosphere.
GPS receivers technology has evolved at a surprising pace: nowadays they have sufficient measurement quality as to be used in geodetic studies, together with other techniques such as the Very Long Base Interferometry (VLBI), and in atmospheric studies whose results can be input into meteorological analysis.
In the thesis "Atmospheric Tomography Using Satellite Radio Signals" we have focused on the use of GPS system due to the better quality and quantity of references and tools for the data processing. This notwithstanding, we have proven the possibility to broaden the concept to include any other radio signal transmitting satellite system as an atmospheric sounder. The thesis has been divided into two main areas: GPS data processing to extract the information related to the atmospheric parameters under study, and the implementation of tomographic techniques to the solution of the inverse problem. In particular, tomography has been applied to the ionosphere and to the neutral atmosphere. In both cases, results have a socio-economic impact: a) monitoring the ionosphere is essential for radio transmissions across it because of the perturbations it may produce on the signal, and b) estimating water vapour content in the troposphere is highly useful for meteorological and climate forecast
For the ionospheric tomography we initally only used the data from the global IGS network. Vertical resolution was afterwards improved using the occultation data of the GPS/MET experiment. The improvement, however, was limited to the region where these data existed. Finally, we used altimeter data from the TOPEX/POSEIDON satellite to improve the maps and to prove the radar altimeter calibration capability of the tomographic technique.
The application to the troposphere was possible after the improvement and refinement of both the GPS data processing and the tomographic inversion. The first results were obtained using the experimental data from the permanent network in Kilauea, Hawaii. The particular geometry of the receivers in this local network made it highly suited for these initial results, which proved the possibility of obtaining spatio-temporal representations of the troposphere using GPS data. The data analysis of the REGINA campaign, which took place at the Onsala Space Observatory, provided the description of a complex meteorological phenomenon using only GPS data tropospheric tomography. We verified the results with a direct comparison with radiosonde data.
Concluding, we have demonstrated the capabilities of atmospheric tomography using satellite radio signals, with particular emphasis on the GPS signals.
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Arciniegas, Mosquera Andrés Felipe. "Analyse de méthodes statistiques en traitement du signal pour les tomographies acoustique et ultrasonore des arbres sur pied." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4746/document.
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La tomographie acoustique est une méthode d'imagerie permettant de réaliser des cartographies bidimensionnelles du plan radial-transverse des arbres en fonction de la vitesse (ou la lenteur) des ondes élastiques de basse fréquence (<20 kHz). Les images couramment obtenues avec les appareils commerciaux possèdent une résolution spatiale faible (de l'ordre de quelques centimètres) et sont parfois difficiles à interpréter. Cette résolution est limitée par l'utilisation des ondes de basse fréquence, le faible nombre de sondes et la non-prise en compte des propriétés du bois (anisotropie, hétérogénéité). À ce jour, il n'existe pas d'appareils de terrain utilisant les ultrasons, spécialement adaptés à l'imagerie des arbres sur pied. Compte-tenu des limitations évoquées, nous proposons ici deux études cherchant à améliorer la qualité des images des tomographie acoustique et ultrasonore. Dans un premier temps nous comparons des méthodes de traitement du signal pour la mesure du temps de propagation et nous en précisons des limites expérimentales de validité. L'approche développée a permis de sélectionner les méthodes de traitement du signal en caractérisant les erreurs systématiques et aléatoires induites en fonction du niveau de bruit. Dans un deuxième temps, une étude numérique de la robustesse d'algorithmes de reconstruction est proposée. Deux nouveaux algorithmes sont présentés et comparés à deux algorithmes classiques utilisés dans les appareils commerciaux. Cette comparaison est axée sur les critères liés aux contraintes expérimentales (faible nombre de sondes et mesures bruitées) et aux exigences techniques (faible temps de calcul) pour une utilisation sur le terrainAcoustic tomography is an imaging technique used to perform two-dimensional mappings of the radial-transverse plane of trees, based on the velocity (or the slowness) of low frequency elastic waves (<20 kHz). The images currently obtained with the commercial devices have a low spatial resolution (of the order of a few centimeters) and are difficult to interpret. These resolution is limited by the use of low frequency waves, the low number of sensors and the fact of not taking into account the properties of wood (anisotropy, heterogeneity). To date, there are no field devices using ultrasound, specially adapted for standing trees imaging. Taking into account the limitations mentioned previously, we present hereby two studies that aim to improve the quality of acoustic and ultrasonic tomography images. In the first part of this work we compare signal-processing methods for the measurement of the propagation time and we specify experimental limits of validity. The approach developed permitted to choose the signal-processing methods by characterizing their systematic and random errors associated with the noise level. In the second part of this work, a numerical study of the robustness of reconstruction algorithms is proposed. Two new reconstruction algorithms are presented and compared to two conventional algorithms used in the commercial devices. These comparison is based on the criteria related to experimental constraints (low number of sensors and noisy measurements) and technical requirements (low computation time) for use in the field
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Ouksili, Zehor. "Compensation du mouvement respiratoire dans les images TEP/TDM thoraciques." Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0025/document.
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Cette thèse traite du mouvement respiratoire dans l'imagerie TEP/TDM. L'imagerie TEP est une modalité à exposition longue très influencée par les mouvements involontaires du patient. Ces mouvements produisent des artéfacts dont les conséquences sont sérieuses pour le diagnostic car les tumeurs paraissent plus larges et moins actives. Cette thèse contribue à la résolution de ce problème. En plus de proposer l'architecture d'un système d'acquisition TEP/TDM synchronisée à la respiration, on y développe trois méthodes de traitement de signal et d'images qui peuvent être appliquées pour résoudre différents sous-problèmes: Une méthode originale de segmentation et caractérisation du signal respiratoire pour découvrir les patterns respiratoires "normaux" du patient, une méthode de reconstruction TDM-4D qui permet d'obtenir des images anatomiques du corps à chaque niveau respiratoire désiré et un algorithme itératif amélioré pour reconstruire des images TEP-4D compensées en mouvement respiratoire. Toutes ces méthodes et algorithmes ont été validés et testés sur des données simulées, des données de fantômes, et des données réelles de patientsThis thesis deals with respiratory motion in PET/CT images. It is well known that PET is a modality that requires a long exposure time. During this time, patients moves and breath. These motions produce undesirable artefacts that alter seriously the images and their precision. This has important consequences when diagnosing thoracic, and particularly pulmonary, cancer. Tumours appear larger than they really are and their activity is weaker. This thesis proposes to contribute to solving these problems.We propose the architecture of an integrated PET/CT acquisition system synchronized to respiration. We also develop signal and image processing methods that can be applied to eliminating respiratory artefacts in CT and PET images. The thesis brings three main contributions : An original respiratory signal segmentation and characterization to detect "normal" respiratory patterns, a 4D-CT reconstruction method that creates 3D images of the whole body for any respiratory level and an enhanced iterative algorithm for reconstructing 4D-PET images without respiratory artefacts. The developed methods have validated and tested on simulated, phantom and real patients' data
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Ding, Yang. "Analyse morphologique de la microstructure 3D de réfractaires électrofondus à très haute teneur en zircone : relations avec les propriétés mécaniques, chimiques et le comportement pendant la transformation quadratique-monoclinique." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2012. http://pastel.archives-ouvertes.fr/pastel-00743511.
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Les THTZ (réfractaires électrofondus à Très Haute Teneur en Zircone) sont des matériaux utilisés pour la construction de fours verriers. Ils sont composés d'un squelette dendritique de zircone imprégné de phase vitreuse. Cette étude, qui fait partie du programme national de recherche NOREV (Nouveaux REfractaires Verriers), financé par l'ANR (Agence Nationale pour la Recherche), vise à étudier les influences de la morphologie tridimensionnelle de la microstructure et des propriétés des phases sur le comportement mécanique du THTZ, en particulier pendant la transformation quadratique-monoclinique qui intervient lors du refroidissement post-coulée. Les microstructures 3D de différents matériaux ont été investiguées par tomographie X à l'ESRF (synchrotron de Grenoble). Les images 3D segmentées ont donné lieu à des analyses d'images permettant de caractériser la topologie microstructurale des matériaux, à travers de mesures de covariance, de tortuosité et de percolation. Une relation entre la vitesse d'attaque par l'acide fluorhydrique (HF) et la densité de surface du squelette de zircone a été identifiée. En segmentant le squelette de zircone par la méthode des bassins versants (watershed), nous avons pu comparer le niveau de connectivité du réseau de zircone des différents matériaux. Les résultats sont corrélés avec les calculs numériques de la rigidité microstructurale du squelette des matériaux. Après attaque acide et à haute température, un phénomène de flexibilité a été observé sur des éprouvettes minces et a pu être mis en relation avec la connectivité des matériaux. Les mesures de dilatation lors de cycles thermiques ont mis en évidence les effets induits par l'ajout d'yttrine. La phase vitreuse joue un rôle important pendant la transformation de quadratique à monoclinique, en limitant l'endommagement microstructural des matériaux. Le THTZ dopé par l'ajout de 7% d'yttrine présente des propriétés très différentes des autres matériaux : il est plus rigide et ne subit plus la transformation martensitique. Des calculs par éléments finis tridimensionnels, réalisées à partir de volumes élémentaires de la microstructure réelle, ont permis d'estimer l'influence des propriétés des phases constituantes, de leur morphologie et des conditions aux limites sur la contrainte interne responsable de l'endommagement microstructural.
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Sperlich, B., D. P. Born, K. Kaskinoro, K. K. Kalliokoski, and Marko Laaksonen. "Squeezing the Muscle : Compression Clothing and Muscle Metabolism during Recovery from High Intensity Exercise." Mittuniversitetet, Avdelningen för hälsovetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-18973.
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The purpose of this experiment was to investigate skeletal muscle blood flow and glucose uptake in m. biceps (BF) and m. quadriceps femoris (QF) 1) during recovery from high intensity cycle exercise, and 2) while wearing a compression short applying ~37 mmHg to the thigh muscles. Blood flow and glucose uptake were measured in the compressed and non-compressed leg of 6 healthy men by using positron emission tomography. At baseline blood flow in QF (P = 0.79) and BF (P = 0.90) did not differ between the compressed and the non-compressed leg. During recovery muscle blood flow was higher compared to baseline in both compressed (P<0.01) and non-compressed QF (P<0.001) but not in compressed (P = 0.41) and non-compressed BF (P = 0.05; effect size = 2.74). During recovery blood flow was lower in compressed QF (P<0.01) but not in BF (P = 0.26) compared to the non-compressed muscles. During baseline and recovery no differences in blood flow were detected between the superficial and deep parts of QF in both, compressed (baseline P = 0.79; recovery P = 0.68) and non-compressed leg (baseline P = 0.64; recovery P = 0.06). During recovery glucose uptake was higher in QF compared to BF in both conditions (P<0.01) with no difference between the compressed and non-compressed thigh. Glucose uptake was higher in the deep compared to the superficial parts of QF (compression leg P = 0.02). These results demonstrate that wearing compression shorts with ~37 mmHg of external pressure reduces blood flow both in the deep and superficial regions of muscle tissue during recovery from high intensity exercise but does not affect glucose uptake in BF and QF. © 2013 Sperlich et al.:doi 10.1371/journal.pone.0060923
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Tireira, Aly. "Endommagement dans les alliages AlSi12 pour moteurs automobiles : Observations in situ et modélisation micromécanique." Thesis, Saint-Etienne, EMSE, 2015. http://www.theses.fr/2015EMSE0780/document.
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Cette thèse s'intéresse aux mécanismes de déformations et d’endommagement dans les alliages de coulée pour l’industrie automobile. Les études ont porté sur un alliage modèle contenant 12% de silicium et des éléments d’addition. Il a été fabriqué par le procédé squeeze-casting (coulée sous haute pression) au LKR de l’Université Technologique de Vienne avec laquelle cette thèse s’est déroulée en collaboration. Des essais de traction in situ dans le MEB ainsi que sous tomographie aux rayons X ont permis de suivre l’évolution des microstructures pendant le chargement. Une attention particulière a été portée sur les mécanismes d’initiation et de propagation de l’endommagement. Par ailleurs la technique de la corrélation d’images numérique 2D spécialement développée pour être appliquée à des images MEB a été utilisée pour mesurer les mécanismes d’endommagement à l’échelle des inclusions. Une attention particulièreest portée sur les mécanismes de localisation de la déformation. La corrélation d’images numériques 3D appliquée aux images tomographiques a permis une mesure précise de l’évolution de l’endommagement au cours du chargement. Les données expérimentales obtenues ont permis d’adapter un modèle d’endommagement de type GTN. Une dernière étape s’est consacrée à une modélisation micro mécaniques des microstructures. Des méthodes de caractérisations basées sur des hypothèses statistiques ont permis de mesurer et d’identifier des paramètres microstructuraux. Au regard des mécanismes de déformations et de la morphologie des particules de seconde phases, des microstructures modèles sont proposées pour simuler le comportement du matériau réel. Cette démarche servant essentiellement à simplifier les modèles éléments finis afin de gagner en temps de calcul, elle sert aussi à insérer des mécanismes complexes afin de serapprocher le plus possible du comportement réel du matériauThis thesis focuses on the mechanisms of deformation and damage in cast aluminum alloysfor automotive industry. Studies were carried on a model alloy containing 12% silicon and added element like iron and nickel. The material was prepared by squeeze-casting process at the Vienna University of Technology in Austria with which this thesis was held in collaboration. In situ tensile test with X-rays tomographic observations as well as with Scanning Electron Microscope observations were performed. They allowed following microstructure evolution under mechanical loading. Particular attention was paid to the mechanisms of initiation and propagation of damage. Furthermore the technic of Digital Image Correlation (DIC) developed to be applied to SEM images was used to visualize 2D strain localization mechanisms at second phases particles scale. DIC were also applied on tomographic images and allowed to measure accurately in 3D damage evolution under loading. Experimental data obtained from DIC were used to identify parameters of a Gurson Tvergaard Needleman model and allow to simulate by Finite Element Modeling the damage evolution. At last stages micro mechanical studies were performed by FEM using microstructure obtained from tomographic images. Algorithms were developed to measure and identify statistics parameters of the microstructure. In consideration of the mechanism of deformations and second phase particles morphology, generatedmicrostructures are proposed to simulate the behavior of the material. This approach aims to simplify the FEM models by reducing the number of degree of Freedom and, then reduce computation time. It also enables to insert complex mechanisms in the model to be as close as possible the actual behavior of the material
Books on the topic "Leg Tomography"
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1938-, Rager Günter H., and Burch Hansbeat, eds. Computed tomography, anatomy, and morphometry of the lower extremity: With a comparative CT and anatomical atlas containing 48 plates consisting of 123 separate illustrations, and 12 further figures. Berlin: Springer-Verlag, 1990.
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Sabharwal, Nikant, Parthiban Arumugam, and Andrew Kelion. Cardiac positron emission tomography (PET). Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198759942.003.0012.
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As in single photon emission computed tomography (SPECT), positron emission tomography (PET) involves the injection of a radiopharmaceutical, the physiological properties of which determine its distribution within the patient. The labelling radionuclide then allows this distribution to be imaged. The value of cardiac PET as a routine clinical tool, particularly for perfusion imaging, was previously limited by the expense and scarcity of cameras and the short half-lives of the radionuclides with complex radiochemistry. The need for an on-site cyclotron to produce these radiopharmaceuticals made a clinical service non-viable. A number of recent developments, however, have led to renewed interest in cardiac PET. This chapter covers PET instrumentation, detail on the radiopharmaceuticals used in cardiac PET, and a number of sections on F-fluorodeoxyglucose (F-FDG) PET covering infection and inflammation imaging.
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Buechel, Ronny R., and Aju P. Pazhenkottil. Basic principles and technological state of the art: hybrid imaging. Edited by Philipp Kaufmann. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198784906.003.0121.
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The core principle of hybrid imaging is based on the fact that it provides information beyond that achievable with either data set alone. This is attained through the combination and fusion of two datasets by which both modalities synergistically contribute to image information. Hybrid imaging is, thus, more powerful than the sum of its parts, yielding improved sensitivity and specificity. While datasets for integration may be obtained by a variety of imaging modalities, its merits are intuitively best exploited when combining anatomical and functional imaging, particularly in the setting of evaluation of coronary artery disease (CAD) as this combination allows a comprehensive assessment with regard to presence or absence of coronary atherosclerosis, the extent and severity of coronary plaques, and the haemodynamic relevance of stenosis. In clinical practice, the combination of CT coronary angiography (CCTA) with myocardial perfusion studies obtained by single-photon emission computed tomography (SPECT) and by positron emission tomography (PET) has been well established. Recent literature also reports on the feasibility of combining CCTA with cardiac magnetic resonance imaging. Finally, recent advances in CCTA and SPECT imaging have led to a substantial reduction of radiation exposure, now allowing for comprehensive morphological and functional diagnostic work-up by cardiac hybrid SPECT/CCTA imaging at low radiation dose exposures ranging below 5 mSv.
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Sabharwal, Nikant, Parthiban Arumugam, and Andrew Kelion. Introduction to nuclear cardiology. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198759942.003.0001.
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The cardiologist of the early twenty-first century takes for granted the wide range of imaging modalities at his/her disposal, but it was not always so. At the beginning of the 1970s, invasive cardiac catheterization was the only reliable cardiac imaging technique. Subsequently, nuclear cardiology investigations led the way in the non-invasive assessment of cardiac disease. This chapter covers the history of nuclear cardiology, including important milestones in the development of nuclear medicine. It details the relation of nuclear cardiology to other imaging modalities, covering the common imaging modalities used to evaluate left ventricular function and coronary artery disease, and the challenges of multislice X-ray computed tomography.
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Skupio, Rafał. Zastosowanie nieinwazyjnych pomiarów rdzeni wiertniczych do zwiększenia informacji na temat parametrów skał zbiornikowych. Instytut Nafty i Gazu - Państwowy Instytut Badawczy, 2022. http://dx.doi.org/10.18668/pn2022.237.
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The research carried out in the monograph aimed to create a measurement and interpretation system which is to obtain reliable results of well logging with the accuracy of laboratory measurements. Continuous core measurements allow for the generation of logging results without the impact of the borehole and facilitate the depth matching of the core to well log data. Four main chapters can be distinguished in this work: research methodology with a description of the devices used; partial results of core measurements made on various types of rocks; a proposal for a research system, and comprehensive data interpretation for selected boreholes. The methodological part concerned the description of the equipment for continuous measurements of cores in the field of natural gamma radioactivity (K, U, Th) with the application for bulk density measurements using the gamma-gamma method, X-ray fl uorescence spectrometers (XRF) for measuring the chemical composition of rocks and computed tomography (CT) for imaging of the core structure as well as determination of radiological density in Hounsfi eld units (HU). Rock studies were carried out on material representing formations of diff erent lithologies, such as shales, sandstones, limestones, dolomites, anhydrite, siltstones and heterolithic sandstone-siltstone-claystone complexes. The results of measurements made using individual methods have been described in detail and compared with the results of laboratory measurements and well logging data. Test measurements with data processing and interpretation were made on the cores from five boreholes (T-1, O-4, Pt-1, L-7, P-5H), whereas a comprehensive interpretation of the results was carried out for three other boreholes (J-1, P-4, T-2). The new methodology of spectral gamma measurements made it possible to obtain precise concentrations of potassium, uranium and thorium in rocks with high and low radioactivity. The results made it possible to standardise the archival gamma-ray logs made with the Russian-type probes from imp/min to API standard units and to obtain data on the content of K, U, and Th in the core intervals. Using the Cs-137 source in the device for the gamma equipment made it possible to carry out measurements of the bulk density in g/cm3 units. The lithological interpretation based on XRF measurements and mineralogical-chemical models allowed to obtain logs with increased resolution and a more signifi cant number of minerals than was the case with the interpretation of the well logging. In addition, it has been shown that the XRF measurement methodology can be used during the geosteering procedure. The results of the core tests using the CT computed tomography method were presented in combined images and continuous curves of density in HU units. The experience and the presentation of the full scope of measurement and interpretation workflow allowed to propose a procedure for conducting a full range of analyses, considering various types of material provided for research. The procedure considers the full range of analyses as well as the measurements of selected parameters depending on the client’s needs. Keywords: petrophysics, core analyses, XRF spectrometry, computed tomography, gamma profiling, lithological interpretation
Book chapters on the topic "Leg Tomography"
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List-Hellwig, E., and H. Meents. "Magnetic Resonance Imaging and Computed Tomography in Advanced Chronic Venous Insufficiency." In Management of Leg Ulcers, 109–13. Basel: KARGER, 1999. http://dx.doi.org/10.1159/000060634.
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Agrawal, Sumit, and Sri Rajasekhar Kothapalli. "Functional and Molecular Photoacoustic Computed Tomography Using Light Emitting Diodes." In LED-Based Photoacoustic Imaging, 267–302. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-3984-8_11.
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Francis, Kalloor Joseph, Yoeri E. Boink, Maura Dantuma, Mithun Kuniyil Ajith Singh, Srirang Manohar, and Wiendelt Steenbergen. "Light Emitting Diodes Based Photoacoustic and Ultrasound Tomography: Imaging Aspects and Applications." In LED-Based Photoacoustic Imaging, 245–66. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-3984-8_10.
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Allen, Thomas J. "High-Power Light Emitting Diodes; An Alternative Excitation Source for Photoacoustic Tomography." In LED-Based Photoacoustic Imaging, 23–43. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-3984-8_2.
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"Maria, a 15-Year-Old Girl with Lower Extremity Weakness." In Pediatric Hospital Medicine: A Case-Based Educational Guide, 447–58. American Academy of PediatricsItasca, IL, 2022. http://dx.doi.org/10.1542/9781610025935-case32.
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CASE PRESENTATION A 15-year-old previously healthy girl, Maria, is brought to the emergency department (ED) by emergency medical services for rapidly progressing left lower extremity weakness. Maria has been experiencing left leg weakness for the last 2 weeks after injuring her left ankle while playing basketball, but when she suddenly was unable to stand on her left leg, her father became alarmed and called 911. Upon Maria’s arrival to the ED, the ED physician obtains an immediate computed tomography (CT) scan of her head, which shows no abnormality. Radiographs of the left lower extremity from the hip to foot are also obtained and are normal. The ED physician is concerned about an underlying neurologic cause for Maria’s symptoms and calls you to ask that you evaluate her for admission.
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Tobin, W. Oliver. "Headache, Radicular Pain, and Enhancing Lesions." In Mayo Clinic Cases in Neuroimmunology, edited by Andrew McKeon, B. Mark Keegan, and W. Oliver Tobin, 225–27. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780197583425.003.0073.
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A 37-year-old right-handed woman sought care for a dull headache present for 6 months, which was followed by the development of radicular pain in the left leg radiating down the back of her leg into her foot, with associated left foot numbness. Magnetic resonance imaging of the lumbar spine showed an enhancing lesion within the conus. She was referred for neurosurgical evaluation and underwent magnetic resonance imaging of the entire neuraxis, which showed an enhancing lesion in the left cerebellum. She underwent a left cerebellar debulking surgical procedure. Postoperative diplopia developed for approximately 1 month and then subsequently resolved. She walked with a walker after surgery, with progressive deterioration in gait. Two months after surgery a postural tremor developed in the left arm and leg. She was referred for neurologic evaluation. Pathologic evaluation of cerebellar tissue showed foamy histiocytes and xanthomatous cells that stained positive for CD68 (KP1). Staining for CD1a was negative. Tissue immunohistochemistry for the BRAF V600E sequence variation was negative. No hyponatremia was detected. Positron emission tomography/computed tomography of the body from vertex to toes indicated hypermetabolism in the distal femur and proximal tibia. Examination and imaging findings were consistent with a diagnosis of multifocal Erdheim-Chester disease. The patient was initially treated with pegylated interferon, with clinical and radiographic progression. She was subsequently treated with vemurafenib and dexamethasone, with continued radiologic progression. Treatment with radiotherapy and cladribine were also unsuccessful. At that point, next-generation sequencing of cerebellar tissue showed a BRAF V471F sequence variation. She was then treated with trametinib, which resulted in a decrease in size of the cerebellar lesion and growth stabilization of the conus lesion. Histiocytic neoplasms are a heterogeneous group of multisystem disorders, primarily including Erdheim-Chester disease, Langerhans cell histiocytosis, and Rosai-Dorfman disease. Although initially thought to represent inflammatory processes, recent insights into their genomic architecture have shown that they are derived from macrophage-lineage neoplasms.
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Campo, Rocio Vazquez Do, and Divyanshu Dubey. "Ascending Painful Paresthesias, Progressive Ataxia, and Bilateral Foot Drop." In Mayo Clinic Cases in Neuroimmunology, edited by Andrew McKeon, B. Mark Keegan, and W. Oliver Tobin, 128–30. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780197583425.003.0041.
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A 63-year-old woman had development of ascending paresthesias with lancinating and stabbing pain in all extremities. The symptoms began asymmetrically in the left leg and progressed to involve the right leg and both hands. She noticed progressive bilateral leg weakness, gait instability, and new numbness in the left middle back. She had recurrent falls and required the use of a cane and eventually a walker. She had 18.2 kg of weight loss. She had no autonomic symptoms or bladder or bowel dysfunction. Examination 1 year after symptom onset showed an emaciated, ill-appearing woman. On neurologic examination, she had marked gait ataxia with profound proprioceptive loss in all extremities, asymmetrically reduced pinprick sensation distal to the left thigh, right knee, and both forearms, as well as bilateral middle thoracic dermatomes. She had bilateral foot drop and mild weakness in bilateral hamstring and intrinsic hand muscles. Her deep tendon reflexes were globally absent. Toes were mute to plantar stimulation. Magnetic resonance imaging of the entire spine demonstrated subtle increased T2 signal in the posterior columns extending along cervical and thoracic segments and patchy gadolinium enhancement of the cervical and lumbosacral nerve roots. Electrodiagnostic testing demonstrated a length-dependent axonal sensorimotor peripheral neuropathy. Cerebrospinal fluid analysis showed an increased protein concentration, 9 cerebrospinal fluid-restricted oligoclonal bands, increased immunoglobulin G index and synthesis rate, and normal blood cell count. Paraneoplastic antibody evaluation showed high titers of collapsin-response mediator protein 5-immunoglobulin G autoantibodies in the serum and cerebrospinal fluid. Whole-body 18F-fludeoxyglucose–positron emission tomography indicated multiple hypermetabolic mediastinal and hilar lymph nodes. Biopsy of a mediastinal lymph node was consistent with small cell lung carcinoma. The patient was diagnosed with collapsin-response mediator protein 5- immunoglobulin G paraneoplastic myeloneuropathy associated with small cell carcinoma of the lung. The patient received a trial of intravenous methylprednisolone followed by chemotherapy, along with chest and prophylactic brain radiotherapy. She achieved a short period of clinical stabilization and mild improvement in gait and limb ataxia. Subsequently, her ataxia and bilateral leg weakness worsened. Her clinical condition rapidly deteriorated, and she became severely malnourished and bedridden, dying 12 weeks later, 2 years after symptom onset. Collapsin-response mediator protein 5- immunoglobulin G antibodies have been associated with asymmetric, painful polyradiculoneuropathy with coexisting myelopathy, often in the setting of thymoma or small cell lung cancer.
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Tobin, W. Oliver. "New-Onset Right-Sided Numbness and Double Vision." In Mayo Clinic Cases in Neuroimmunology, edited by Andrew McKeon, B. Mark Keegan, and W. Oliver Tobin, 14–16. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780197583425.003.0004.
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A 40-year-old right-handed man sought care for right hand numbness, right-sided facial numbness, and diplopia progressing to maximal severity over 10 days. At his worst he was unable to write. His symptoms remained maximal for 4 weeks. He was hospitalized and treated with 5 days of intravenous methylprednisolone. He improved to approximately 95% of normal over 4 weeks. He had residual mild right-sided facial and right leg numbness. Antibodies to JC polyoma virus and varicella-zoster virus were positive, which indicated prior exposure to these viruses. Total 25-hydroxyvitamin D level was low at 8.2 ng/mL. Optical coherence tomography findings were normal. Magnetic resonance imaging of the brain performed 3 months after the onset of symptoms demonstrated a T2-hyperintense lesion in the left midbrain peduncle extending into the upper pons, without gadolinium enhancement. A small area of T2 hyperintensity was seen in the right frontal deep white matter. Follow-up brain magnetic resonance imaging showed almost complete resolution of the left midbrain peduncle lesion with persistence of the right frontal deep white matter lesion. Spinal fluid analysis showed 1 white blood cell/µL with 95% lymphocytes, protein 35 mg/dL, 0 unique oligoclonal bands, and normal immunoglobulin G index (0.54). A diagnosis of clinically isolated syndrome-first episode of multiple sclerosis was made. After detailed discussion with the patient, he elected to commence disease-modifying therapy with fingolimod. He underwent routine monitoring with magnetic resonance imaging of the brain and cervical and thoracic spine on an annual basis, without any further relapses at 5-year follow-up. Patients with typical demyelinating syndromes may not always fulfill the diagnostic criteria for multiple sclerosis. After careful exclusion of other mimicking conditions, most notably aquaporin-4-immunoglobulin G– and myelin oligodendrocyte glycoprotein-immunoglobulin G–associated disease, a diagnosis of clinically isolated syndrome may be made.
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"Image processing Ting-Yim Lee, Xiaogang Chen, and Kenneth A Miles." In Multi-Detector Computed Tomography in Oncology, 77–88. CRC Press, 2007. http://dx.doi.org/10.3109/9780203001158-8.
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Old, Oliver. "Vascular surgery." In Oxford Assess and Progress: Clinical Surgery. Oxford University Press, 2014. http://dx.doi.org/10.1093/oso/9780199696420.003.0025.
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As the patient in clinic describes the cramp-like pain that he gets in his calf when he walks, a pain that disappears on resting but which is exacerbated by walking up hills and necessitates him stopping to look in shop windows when out and about, you will be thinking about questioning him for risk factors for vascular disease. Atherosclerosis is a systemic disease. Identification and early treatment of diabetes, hypercholesterolaemia, hypertension, and provision of antiplatelet agents and smoking cessation therapy will confer important cardio- and cerebroprotective benefits. Acute vascular emergencies requiring an urgent response include the patient with sudden onset, limb-threatening ischaemia; the collapsed patient with a ruptured aortic aneurysm; and the patient in whom haemorrhage or ischaemia comprises part of the picture of complex trauma. Rapid, but thorough examination, appropriate resuscitation, and judicious use of diagnostic imaging will help to underpin urgent management and interventions necessary to obtain the best outcomes for these patients. Despite increasing reliance on minimally invasive diagnostic modalities including duplex Doppler ultrasound, magnetic resonance angiography, and computed tomography angiography, principles of history taking and good clinical examination remain of paramount importance. Observation to detect nuances of ischaemic trophic changes and skin colour, as well as more overt signs of necrosis, gangrene, and ulceration, complements palpation of pulses, detection of subtle changes in skin temperature, delayed capillary refill, and presence of sensory neuropathy. A positive Buerger’s test, with pallor of the foot and venous guttering on leg elevation, and rubor (redness), due to reactive hyperaemia on dependency, may help clinch the diagnosis of critical limb ischaemia when other diagnostic features are equivocal. Careful distinction between features of arterial insufficiency, venous hypertension, and diabetic neuropathy may help to determine aetiology of a recalcitrant lower limb ulcer and the consequent course of management. In the UK, vascular surgery has recently become an independent surgical specialty. This chapter will test your understanding of signs and symptoms of vascular disease and will hopefully stimulate your understanding of priorities for investigation and management of the range of conditions comprising this exciting sphere of surgery.
Conference papers on the topic "Leg Tomography"
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Hahamovich, Evgeny, Sagi Monin, Yoav Hazan, Ahiad Levi, Michael Nagli, and Amir Rosenthal. "3D Optoacoustic Tomography Via Spatially Codded Detectors." In European Conference on Biomedical Optics. Washington, D.C.: Optica Publishing Group, 2021. http://dx.doi.org/10.1364/ecbo.2021.em2d.4.
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Novel method for spatially coding ultrasonic detectors is described and experimentally demonstrated by in vivo Optoacoustic imaging of a mouse leg using a single detector, effectively transformed to a 2D detection array with 1763 elements.
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Jones, Rebecca, Brett C. Byram, Siegfried Schlunk, Jaime E. Tierney, and Ryan Hsi. "The impact of mid lag spatial coherence parameters on coherent target detection." In Ultrasonic Imaging and Tomography, edited by Nicole V. Ruiter and Brett C. Byram. SPIE, 2019. http://dx.doi.org/10.1117/12.2514118.
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Leskinen, Jarkko, Aki Pulkkinen, Jenni Tick, and Tanja Tarvainen. "Photoacoustic tomography setup using LED illumination." In Opto-Acoustic Methods and Applications in Biophotonics, edited by Vasilis Ntziachristos and Roger Zemp. SPIE, 2019. http://dx.doi.org/10.1117/12.2526723.
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al-Rifaie, Mohammad Majid, and Tim Blackwell. "Swarm led tomographic reconstruction." In GECCO '22: Genetic and Evolutionary Computation Conference. New York, NY, USA: ACM, 2022. http://dx.doi.org/10.1145/3512290.3528737.
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Ntziachristos, Vasilis. "Going deeper than microscopy with multi-spectral optoacoustic tomography (MSOT)." In LEOS 2009 -22nd Annuall Meeting of the IEEE Lasers and Electro-Optics Society (LEO). IEEE, 2009. http://dx.doi.org/10.1109/leos.2009.5343228.
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Krstajic, N., R. Smallwood, D. T. D. Childs, P. D. L. Greenwood, M. Hugues, K. Kennedy, M. Hopkinson, et al. "Optical coherence tomography with high power quantum-dot superluminescent diodes." In LEOS 2009 -22nd Annuall Meeting of the IEEE Lasers and Electro-Optics Society. LEO 2009. IEEE, 2009. http://dx.doi.org/10.1109/leos.2009.5343317.
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Mohajerani, Pouyan, Ali Behrooz, Ali A. Eftekhar, and Ali Adibi. "A row-action based L1-minimization approach to robust fluorescent tomography." In LEOS 2009 -22nd Annuall Meeting of the IEEE Lasers and Electro-Optics Society (LEO). IEEE, 2009. http://dx.doi.org/10.1109/leos.2009.5343229.
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Shuai Yuan, Qian Li, Renee Naphas, and Yu Chen. "3-D morphological and molecular imaging using multi-modality optical tomography." In LEOS 2009 -22nd Annuall Meeting of the IEEE Lasers and Electro-Optics Society (LEO). IEEE, 2009. http://dx.doi.org/10.1109/leos.2009.5343230.
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Yang, Tongning, and Paul Sava. "3D image-domain wavefield tomography using time-lag extended images." In SEG Technical Program Expanded Abstracts 2013. Society of Exploration Geophysicists, 2013. http://dx.doi.org/10.1190/segam2013-0279.1.
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Roychowdhury, Sushovan, and Tomas Månsson. "On Predicting Weld Specimen Fatigue Life Based on Defect Data." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-15976.
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Abstract Prediction of fatigue life based on internal defect data is an important research topic for components built through both traditional welds and modern additive manufacturing. In this work, a systematic approach is taken to investigate application of fracture mechanics principle for this purpose. To this end, fatigue test samples are prepared from TIG-welded titanium alloy sheets and also representative weld repairs of cast plates. Metro-tomography is employed to obtain information about internal defects in the specimens before fatigue testing. After fatigue testing, fractography is used to identify the defect that led to failure and to gather information on its location and size. The information from metro-tomography and fractography are then directly compared to assess the accuracy of the tomography data. Simple fracture mechanics methods are employed to estimate the fatigue life for each specimen, considering separately tomography and fractography data. Such estimates are then compared with fatigue life from tests. Through such quantitative comparisons, the work highlights the advantages and the challenges of the fracture mechanics approach to assess the fatigue life of test specimens with internal defects. A key observation is that life estimates employing a fracture mechanics approach are reasonable when the defect leading to failure is known, but the challenge may lie in a-priori identification of the defect that would eventually lead to failure.
Reports on the topic "Leg Tomography"
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Tzfira, Tzvi, Michael Elbaum, and Sharon Wolf. DNA transfer by Agrobacterium: a cooperative interaction of ssDNA, virulence proteins, and plant host factors. United States Department of Agriculture, December 2005. http://dx.doi.org/10.32747/2005.7695881.bard.
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Agrobacteriumtumefaciensmediates genetic transformation of plants. The possibility of exchanging the natural genes for other DNA has led to Agrobacterium’s emergence as the primary vector for genetic modification of plants. The similarity among eukaryotic mechanisms of nuclear import also suggests use of its active elements as media for non-viral genetic therapy in animals. These considerations motivate the present study of the process that carries DNA of bacterial origin into the host nucleus. The infective pathway of Agrobacterium involves excision of a single-stranded DNA molecule (T-strand) from the bacterial tumor-inducing plasmid. This transferred DNA (T-DNA) travels to the host cell cytoplasm along with two virulence proteins, VirD2 and VirE2, through a specific bacteriumplant channel(s). Little is known about the precise structure and composition of the resulting complex within the host cell and even less is known about the mechanism of its nuclear import and integration into the host cell genome. In the present proposal we combined the expertise of the US and Israeli labs and revealed many of the biophysical and biological properties of the genetic transformation process, thus enhancing our understanding of the processes leading to nuclear import and integration of the Agrobacterium T-DNA. Specifically, we sought to: I. Elucidate the interaction of the T-strand with its chaperones. II. Analyzing the three-dimensional structure of the T-complex and its chaperones in vitro. III. Analyze kinetics of T-complex formation and T-complex nuclear import. During the past three years we accomplished our goals and made the following major discoveries: (1) Resolved the VirE2-ssDNA three-dimensional structure. (2) Characterized VirE2-ssDNA assembly and aggregation, along with regulation by VirE1. (3) Studied VirE2-ssDNA nuclear import by electron tomography. (4) Showed that T-DNA integrates via double-stranded (ds) intermediates. (5) Identified that Arabidopsis Ku80 interacts with dsT-DNA intermediates and is essential for T-DNA integration. (6) Found a role of targeted proteolysis in T-DNA uncoating. Our research provide significant physical, molecular, and structural insights into the Tcomplex structure and composition, the effect of host receptors on its nuclear import, the mechanism of T-DNA nuclear import, proteolysis and integration in host cells. Understanding the mechanical and molecular basis for T-DNA nuclear import and integration is an essential key for the development of new strategies for genetic transformation of recalcitrant plant species. Thus, the knowledge gained in this study can potentially be applied to enhance the transformation process by interfering with key steps of the transformation process (i.e. nuclear import, proteolysis and integration). Finally, in addition to the study of Agrobacterium-host interaction, our research also revealed some fundamental insights into basic cellular mechanisms of nuclear import, targeted proteolysis, protein-DNA interactions and DNA repair.