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Auswahl der wissenschaftlichen Literatur zum Thema „Soft tissue artefacts“
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Zeitschriftenartikel zum Thema "Soft tissue artefacts"
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Dumas, R., Y. Lafon, E. Jacquelin und L. Chèze. „Soft tissue artefacts: compensation and modelling“. Computer Methods in Biomechanics and Biomedical Engineering 12, sup1 (August 2009): 103–4. http://dx.doi.org/10.1080/10255840903077345.
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Chan, Janet M. „Penile shadow artefact overlapping fractures“. Radiography Open 1, Nr. 1 (01.12.2014): 4. http://dx.doi.org/10.7577/radopen.1202.
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Soft tissue shadows are commonly seen on pelvic radiographs, and radiographers may overlook or are unaware that these shadows could be artefacts. In a case study, shadow of a penis superimposed with the fracture lines at pubic ramus and it was questioned whether a fracture of ramus ischio-pubis is present. Further radiographic views were performed to demonstrate the fractures without any artefact. There are other possible pelvic artefacts that may be seen and neglected on pelvic radiographs, thus it may lead to misdiagnosis of pelvic fracture. This essay should be served as a reminder for radiographers to recognize artefacts and differentiate it from pathology.
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Lazovic, D., J. Franke und C. J. Wirth. „Computerized Tomography and Magnetic Resonance Imaging in Treatment of Congenital Luxation of the Hip“. HIP International 6, Nr. 3 (Juli 1996): 119–23. http://dx.doi.org/10.1177/112070009600600304.
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In treatment of congenital dislocation of the hip, a main aim is to achieve concentricity of reduction. Control by plain x-ray lacks accuracy in determining anteroposterior position. Arthrography and sonography cannot be used when a spica cast is in place. After April 1988, therefore, as an alternative in 16 hips, we have used computed tomography to determine femoral head position, acetabular angle, and extent and integrity of posterior rim. However, the presence of any metallic artefacts, unossified cartilage and the general poor-quality imaging of soft tissue associated with the technique reduce its usefulness. Since January 1990, we have instead used magnetic resonance imaging to control treatment. This technique, in 34 hips, proved accurate in determinating the femoral head position. MRI also gave better images than computed tomography of osseous and cartilaginous structures of the acetabulum and the surrounding soft tissue. Spica casting does not affect the quality of imaging. The effect of metal artefacts can be minimized by using, where necessary, implants of titanium alloy.
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de Vries, W. H. K., H. E. J. Veeger, C. B. T. M. Baten und F. C. T. van der Helm. „Upper extremity Load Spectrum in daily situations: System Accuracy and Soft Tissue Artefacts“. Journal of Biomechanics 40 (Januar 2007): S424. http://dx.doi.org/10.1016/s0021-9290(07)70419-0.
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Metcalf, C. D., C. Phillips, A. Forrester, J. Glodowski, K. Simpson, C. Everitt, A. Darekar, L. King, D. Warwick und A. S. Dickinson. „Quantifying Soft Tissue Artefacts and Imaging Variability in Motion Capture of the Fingers“. Annals of Biomedical Engineering 48, Nr. 5 (19.02.2020): 1551–61. http://dx.doi.org/10.1007/s10439-020-02476-2.
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GÜNTHER, MICHAEL, VIKTOR A. SHOLUKHA, DANNY KESSLER, VEIT WANK und REINHARD BLICKHAN. „DEALING WITH SKIN MOTION AND WOBBLING MASSES IN INVERSE DYNAMICS“. Journal of Mechanics in Medicine and Biology 03, Nr. 03n04 (September 2003): 309–35. http://dx.doi.org/10.1142/s0219519403000831.
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Inverse dynamics is a standard analysis in biomechanics to reconstruct time histories of internal driving forces and torques from measured external forces and segmental kinematics. The main sources of inconsistency leading to analytical artefacts in this process are skin marker and soft tissue motion. These potentially artificial high frequency fluctuations in the joint torques may serve as an erroneous basis of (misleading) assumptions with respect to muscular activity. Here we suggest techniques to reduce these errors. In both parts of this study, high-speed video and force platform data were acquired. In one part, 69 sequences of human barefoot running were sampled followed by an inverse dynamic analysis of the stance leg. The time history of the hip joint torque in the sagittal plane served as a sensitive "detector" of dynamic analysis artefacts. We show that the most important error — the relative skin to bone motion especially of the knee marker — can be reduced significantly by processing kinematic data using bone rigidity (constant segment lengths) and bony contour (frontal knee edge) information. Further on, neglecting significantly initiated soft tissue dynamics in the inverse dynamic model introduces another inconsistency in the analytical process. Therefore, in a second part of this study, soft tissue kinematics from 14 jumping sequences were identified. These data provided a set of coupling parameters of wobbling masses to the bone that were ready to be implemented in the inverse dynamic model. Using realistic bone kinematics mainly avoids phase shifts in the acceleration scenario within the leg, and thus artifical hip torque fluctuations within the whole contact period. In human running, accounting for soft tissue dynamics mainly affects the calculated timing of the hip joint torque during the impact phase.
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Lu, Ming, Cheng-Chung Lin, Tung-Wu Lu, Shi-Nuan Wang und Ching-Ho Wu. „Effects of soft tissue artefacts on computed segmental and stifle kinematics in canine motion analysis“. Veterinary Record 186, Nr. 2 (13.08.2019): 66. http://dx.doi.org/10.1136/vr.105352.
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Skin marker-based motion analysis has been widely used to evaluate the functional performance of canine gait and posture. However, the interference of soft tissues between markers and the underlying bones (soft tissue artefacts, STAs) may lead to errors in kinematics measurements. Currently, no optimal marker attachment sites and cluster compositions are recommended for canine gait analysis. The current study aims to evaluate cluster-level STAs and the effects of cluster compositions on the computed stifle kinematics. Ten mixed-breed healthy dogs affixed with 19 retroreflective markers on the thigh and shank were enrolled. During isolated stifle passive extension, the marker trajectories were acquired with a motion capture system, and the skeletal poses were determined by integrating fluoroscopic and CT images of the bones. The cluster-level STAs were assessed, and clusters were paired to calculate the stifle kinematics. A selection of cluster compositions was useful for deriving accurate sagittal and frontal plane stifle kinematics with flexion angles below 50 per cent of the range of motion. The findings contribute to improved knowledge of canine STAs and their influence on motion measurements. The marker composition with the smallest error in describing joint kinematics is recommended for future applications and study in dogs during dynamic gait assessment.
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Omori, Naoko, Takuya Ueda und Nobuyuki Mitsukawa. „CT-guided mapping in the removal of an impalpable, radiopaque foreign body in subcutaneous tissue: a case report“. Journal of Wound Care 29, Nr. 7 (02.07.2020): 424–26. http://dx.doi.org/10.12968/jowc.2020.29.7.424.
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Small fragments sometimes penetrate the soft tissue, and their depth and location can be difficult to determine accurately. This case study describes localisation of a thin, short wire that had penetrated the soft tissue of a 24-year-old man's back, using computed tomography (CT) with a reference grid made with an angiographic catheter. The axial non-contrast-enhanced CT scan with the grid placed over the affected body part surveyed by the CT scout view showed that the foreign body was buried in fascia 7cm from a puncture wound. Surgical removal of the foreign body was then performed without any sequelae. CT with the use of external references that do not cause metal artefacts is a simple and helpful procedure in localising radiopaque foreign bodies.
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Goodall, Alex Francis, Alex Barrett, Elspeth Whitby und Andrew Fry. „T2*-weighted MRI produces viable fetal “Black-Bone” contrast with significant benefits when compared to current sequences“. British Journal of Radiology 94, Nr. 1123 (01.07.2021): 20200940. http://dx.doi.org/10.1259/bjr.20200940.
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Objectives: Fetal “black bone” MRI could be useful in the diagnosis of various skeletal conditions during pregnancy without exposure to ionizing radiation. Previously suggested susceptibility-weighted imaging (SWI) is not available in the suggested form on all scanners leading to long imaging times that are susceptible to motion artefacts. We aimed to assess if an optimized T2*-weighted GRE sequence can provide viable “black bone” contrast and compared it to other sequences in the literature. Methods: A retrospective study was conducted on 17 patients who underwent fetal MRI. Patients were imaged with an optimized T2*-weighted GRE sequence, as well as at least one other “black-bone” sequence. Image quality was scored by four blinded observers on a five-point scale. Results: The T2*-weighted GRE sequence offered adequate to excellent image quality in 63% of cases and scored consistently higher than the three other comparison sequences when comparing images from the same patient. Image quality was found to be dependent on gestational age with good image quality achieved on almost all patients after 26 weeks. Conclusions: T2*-weighted GRE imaging can provide adequate fetal “black bone” contrast and performs at least as well as other sequences in the literature due to good bone to soft tissue contrast and minimal motion artefacts. Advances in knowledge: T2*-weighted fetal “black-bone” imaging can provide excellent bone to soft tissue contrast without using ionizing radiation. It is as good as other “black bone” sequences and may be simpler and more widely implemented, with less motion artefacts.
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Fearnhead, R. W., M. Pang, N. Mok und K. Kawasaki. „New Artefacts for Old: An Alternative Method of Preparing Hard and Soft Tissue Interfaces of Developing Enamel“. Advances in Dental Research 1, Nr. 2 (Dezember 1987): 366–70. http://dx.doi.org/10.1177/08959374870010022801.
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Serial sections (each from 150 to 200 μm thick) of porcine molar tooth germs within their bony crypts, rodent incisor teeth (in situ), and human extracted teeth were cut with a thin rotating diamond-impregnated disc, without prior embedding. Some specimens were cut unfixed, at room temperature (21°C) or frozen (-70°C), some in fixative, and others cut after fixation. A variety of routine fixatives has been tried, and in general the preservation of hard/soft tissue interfaces is best achieved when fixation precedes cutting. Several histological and histochemical methods have also been tried successfully. The damaged surface layers of the specimens brought about by the cutting disc can be removed after staining, if the section is embedded in a thin sheet of Epon and then thinned by being polished. The method provides a novel way of studying hard/soft tissue junctions.
Dissertationen zum Thema "Soft tissue artefacts"
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Lefebvre, Félix. „Analyse cinématique de l'épaule et du membre supérieur par capture de mouvement avec et sans marqueurs“. Electronic Thesis or Diss., Lyon 1, 2024. http://www.theses.fr/2024LYO10264.
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La caractérisation précise et quantifiée du mouvement humain est essentielle dans de nombreux domaines et particulièrement en pratique clinique et sportive pour exploiter, préserver ou rétablir les capacités motrices. L’anatomie complexe de l’épaule lui confère une capacité de mouvement fine et de grande amplitude, au détriment d’une stabilité fragile et exposée à des risques importants d’altérations pouvant compromettre sa mobilité. Pour estimer la cinématique articulaire du complexe de l’épaule, il est donc nécessaire de disposer d’un système de capture de mouvement qui soit rapide, précis, et applicable en routine. Parmi les nombreux outils utilisés, l’estimation de la cinématique de l’épaule par mesure directe est généralement invasive ou irradiante, et en tout cas non adaptée à l’évaluation systématique. Les méthodes d’estimation cinématique de l’épaule par mesure cutanée indirecte sont plébiscitées, notamment avec marqueurs, mais avec une précision moindre du fait des artefacts des tissus mous. De nombreuses stratégies expérimentales et numériques ont été développées pour en améliorer les performances, sans toutefois donner pleinement satisfaction. Récemment, des méthodes de capture de mouvement sans marqueurs sont apparues mais aucune ne propose à ce jour d’estimations compatibles avec la modélisation cinématique détaillée du complexe de l’épaule. L’objectif de cette thèse était alors de contribuer au développement des outils d’analyse cinématique de l’épaule par capture de mouvement avec et sans marqueurs. Un premier sous-objectif de ce travail de thèse était d’étudier l’influence de l’optimisation du modèle cinématique et du poids des marqueurs de la scapula sur la cinématique scapulaire dans une optimisation multi-segmentaire. Les résultats de cette première étude ont mis en évidence que la redondance des marqueurs, à savoir l’utilisation de plus de trois marqueurs sur la scapula, est recommandée pour l’estimation de la cinématique scapulaire par optimisation multi-segmentaire. Ces résultats ont aussi montré que les poids optimaux sont à la fois spécifiques au participant et au mouvement, mais qu’un jeu de poids moyen par mouvement pouvait améliorer l’estimation de la cinématique scapulaire. Le second sous-objectif de ce travail de thèse était de développer une méthode de capture de mouvement sans marqueurs par algorithme d’apprentissage profond permettant le suivi cinématique du membre supérieur incluant le complexe de l’épaule. Cette seconde étude a consisté à développer un algorithme d’estimation de pose 2D capable d’identifier 20 repères anatomiques sur cinq mouvements différents avec une précision médiane inférieure à 9 px. La méthode de capture de mouvement sans marqueurs développée sur la base de cet algorithme a permis des estimations 3D des repères anatomiques de l’épaule avec une précision moyenne inférieure à 15 mm, aboutissant à une précision cinématique articulaire de 14° pour l’articulation scapulo-thoracique. Les estimations ainsi obtenues sont équivalentes voire meilleures que pour la capture de mouvement avec marqueurs, pour un gain de temps considérable par l’absence de préparation. De futurs travaux sont nécessaires pour transformer la preuve de concept développée en véritable outil de capture de mouvement, et valider son potentiel à devenir la méthode la plus adaptée pour l’estimation cinématique du complexe de l’épaule en routineThe precise and quantified characterization of human movement is essential in many fields, particularly in clinic and sports, to enhance, preserve, or restore motor abilities. The complex anatomy of the shoulder gives it fine and large-range motion capability, at the cost of fragile stability, exposing it to significant risks of impairments that can compromise its mobility. To accurately estimate the kinematics of the shoulder complex, it is necessary to have a motion capture system that is fast, accurate, and suitable for routine use. Among the many tools employed, shoulder kinematic estimation via direct measurement is generally invasive or radiation-based, and in any case not suited for systematic evaluation. Indirect skin-based shoulder kinematic estimation methods, especially those using markers, are widely used but offer lower accuracy due to soft tissue artifacts. Numerous experimental and numerical strategies have been developed to improve their performance, though they have not yet fully satisfied expectations. Recently, markerless motion capture methods have emerged, but to date, none of them provide estimates compatible with the detailed kinematic modeling of the shoulder complex. The objective of this thesis was therefore to contribute to the development of shoulder kinematic analysis tools using both marker-based and markerless motion capture. A first sub-objective of this thesis was to study the influence of kinematic model optimization and scapular marker weight on scapular kinematics in a multibody kinematic optimization. The results of this first study highlighted that marker redundancy, meaning the use of more than three markers on the scapula, is recommended for scapular kinematic estimation in multibody kinematic optimization. These results also showed that the optimal marker weights are both participant- and movement-specific, but that an average weight set per movement could improve scapular kinematic estimation. The second sub-objective of this thesis was to develop a markerless motion capture method using a deep learning algorithm that allows for the kinematic tracking of the upper-limb, including the shoulder complex. This second study involved developing a 2D pose estimation algorithm capable of identifying 20 anatomical landmarks across five different movements with a median accuracy of less than 9 px. The markerless motion capture method developed based on this algorithm provided 3D estimates of the anatomical landmarks of the shoulder with an average accuracy of less than 15 mm, resulting in an articular kinematic accuracy of 14° for the scapulothoracic joint. These estimates were equivalent to, if not better than, those obtained using marker-based motion capture, with a significant time-saving due to the absence of preparation required. Further research is needed to transform this proof of concept into a fully functional motion capture tool and validate its potential to become the most suitable method for routine shoulder complex kinematic estimation
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Richard, Vincent. „Multi-body optimization method for the estimation of joint kinematics : prospects of improvement“. Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1090/document.
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L'analyse du mouvement humain s'appuie généralement sur des techniques de suivi de marqueurs cutanés pour reconstruire la cinématique articulaire. Cependant, ces techniques d'acquisition présentent d'importantes limites dont les " artefacts de tissus mous " (i.e., le mouvement relatif entre les marqueurs cutanés et le squelette sous-jacent). La méthode d'optimisation multi-segmentaire viseà compenser ces artefacts en imposant aux trajectoires de marqueurs les degrés de liberté d'un modèle cinématique prédéfini. Les liaisons mécaniques modélisant classiquement les articulations empêchent toutefois une estimation satisfaisante de la cinématique articulaire. Cette thèse aborde des perspectives d'amélioration de la méthode d'optimisation multi-segmentaire pour l'estimation de la cinématique articulaire du membre inférieur,à travers différentes approches : (1) la reconstruction de la cinématique par suivi de la vitesse angulaire, de l'accélération et de l'orientation de centrales inertiellesà la place du suivi de marqueurs, (2) l'introduction d'un modèle articulaire élastique basé sur la matrice de raideur du genou, permettant une estimation physiologique de la cinématique articulaire et (3) l'introduction d'un modèle des artefacts de tissus mous " cinématique-dépendant ", visantà évaluer et compenser les artefacts de tissus mous simultanément avec l'estimation la cinématique articulaire. Ce travail a démontré la polyvalence de la méthode d'optimisation multi-segmentaire. Les résultats obtenus laissent espérer une amélioration significative de cette méthode qui devient de plus en plus utilisée en biomécanique, en particulier pour la modélisation musculo-squelettiqueHuman movement analysis generally relies on skin markers monitoring techniques to reconstruct the joint kinematics. However, these acquisition techniques have important limitations including the "soft tissue artefacts" (i.e., the relative movement between the skin markers and the underlying bones). The multi-body optimization method aims to compensate for these artefacts by imposing the degrees of freedom from a predefined kinematic model to markers trajectories. The mechanical linkages typically used for modeling the joints however prevent a satisfactory estimate of the joint kinematics. This thesis addresses the prospects of improvement of the multi-body optimization method for the estimation of joint kinematics of the lower limb through different approaches: (1) the reconstruction of the kinematics by monitoring the angular velocity, the acceleration and the orientation of magneto-inertial measurement units instead of tracking markers, (2) the introduction of an elastic joint model based on the knee stiffness matrix, enabling a physiological estimation of joint kinematics and (3) the introduction of a "kinematic-dependent" soft tissue artefact model to assess and compensate for soft tissue artefact concurrently with estimating the joint kinematics. This work demonstrated the versatility of the multi-body optimization method. The results give hope for significant improvement in this method which is becoming increasingly used in biomechanics, especially for musculoskeletal modeling
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Bonci, Tecla. „La reconstruction du mouvement du squelette : l'enjeu de l'artefact des tissus mous“. Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10056/document.
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Lors de l'analyse 3D du mouvement humain basée sur des marqueurs cutanés, la position des os ne peut être qu'indirectement estimée. Au cours d'une tâche, les déformations des tissus mous génèrent des déplacements des marqueurs par rapport à l'os : les artefacts de tissus mous (STA), entraînant des effets dévastateurs sur l'estimation de la position. La compensation des STA demeure une question ouverte. L'objectif de cette thèse est de contribuer à la solution de cette question cruciale. La modélisation des STA en utilisant des variables spécifiques mesurables est une condition préalable à son élimination. Un modèle corrigeant les trajectoires individuelles de marqueurs de la cuisse, calibré par des mesures directes des STA, est d'abord présenté. Les STA sont modélisés comme une combinaison linéaire des angles articulaires impliqués. Trois représentations des STA par une série de modes sont proposées : déplacements de marqueurs individuels, transformations géométriques de clusters de marqueurs (MCGT), et variations de forme de l'enveloppe de peau. Le MCGT permet de dissocier les composantes rigides et non rigides. Il a été démontré que seule la composante rigide affecte la cinématique articulaire. Un modèle de cette composante est alors défini pour les clusters cuisse et jambe. Un compromis acceptable entre la correction des STA et le nombre de paramètres a ainsi été obtenu. Les principales applications sont de générer une simulation réaliste des STA ; et surtout, en se concentrant sur la composante rigide, le modèle permet une reconstruction satisfaisante des STA avec moins de paramètres, ce qui facilite son incorporation dans un algorithme d'estimation de la position osseuseIn 3D human movement analysis performed using stereophotogrammetry and skin markers, bone pose can be only indirectly estimated. During a task, soft tissue deformations make the markers move with respect to the underlying bone generating soft tissue artefacts (STA), causing devastating effects on pose estimation and its compensation remains an open issue. The thesis’ aim was to contribute to the solution of this crucial issue. Modelling STA using measurable trial-specific variables is a prerequisite for its removal from marker trajectories. Two STA model architectures are proposed. A thigh marker-level model is first presented. STA was modeled as a linear combination of joint angles involved in the task. The model was calibrated with direct STA measures. The considerable number of model parameters led to defining STA approximations. Three definitions were proposed to represent STA as series of modes : individual marker displacements, marker-cluster geometrical transformations (MCGT), and skin envelope shape variations. Modes were selected using two criteria : modal energy and selecting them a priori. The MCGT allows to select either rigid or non-rigid components. It was also demonstrated that only the rigid component affects joint kinematics. A model of thigh and shank rigid component at cluster-level was then defined. An acceptable trade-off between STA compensation and number of parameters was obtained. These results lead to two main potential applications : generate realistic STAs for simulation
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Bonci, Tecla <1986>. „The reconstruction of skeletal movement: the soft tissue artefact issue“. Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6928/1/Bonci_Tecla_Tesi.pdf.
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In 3D human movement analysis performed using stereophotogrammetric systems and skin markers, bone pose can only be estimated in an indirect fashion. During a movement, soft tissue deformations make the markers move with respect to the underlying bone generating soft tissue artefact (STA). STA has devastating effects on bone pose estimation and its compensation remains an open question.
The aim of this PhD thesis was to contribute to the solution of this crucial issue. Modelling STA using measurable trial-specific variables is a fundamental prerequisite for its removal from marker trajectories.
Two STA model architectures are proposed. Initially, a thigh marker-level artefact model is presented. STA was modelled as a linear combination of joint angles involved in the movement. This model was calibrated using ex-vivo and in-vivo STA invasive measures. The considerable number of model parameters led to defining STA approximations. Three definitions were proposed to represent STA as a series of modes: individual marker displacements, marker-cluster geometrical transformations (MCGT), and skin envelope shape variations. Modes were selected using two criteria: one based on modal energy and another on the selection of modes chosen a priori. The MCGT allows to select either rigid or non-rigid STA components. It was also empirically demonstrated that only the rigid component affects joint kinematics, regardless of the non-rigid amplitude. Therefore, a model of thigh and shank STA rigid component at cluster-level was then defined. An acceptable trade-off between STA compensation effectiveness and number of parameters can be obtained, improving joint kinematics accuracy.
The obtained results lead to two main potential applications: the proposed models can generate realistic STAs for simulation purposes to compare different skeletal kinematics estimators; and, more importantly, focusing only on the STA rigid component, the model attains a satisfactory STA reconstruction with less parameters, facilitating its incorporation in an pose estimator.
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Bonci, Tecla <1986>. „The reconstruction of skeletal movement: the soft tissue artefact issue“. Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6928/.
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In 3D human movement analysis performed using stereophotogrammetric systems and skin markers, bone pose can only be estimated in an indirect fashion. During a movement, soft tissue deformations make the markers move with respect to the underlying bone generating soft tissue artefact (STA). STA has devastating effects on bone pose estimation and its compensation remains an open question.
The aim of this PhD thesis was to contribute to the solution of this crucial issue. Modelling STA using measurable trial-specific variables is a fundamental prerequisite for its removal from marker trajectories.
Two STA model architectures are proposed. Initially, a thigh marker-level artefact model is presented. STA was modelled as a linear combination of joint angles involved in the movement. This model was calibrated using ex-vivo and in-vivo STA invasive measures. The considerable number of model parameters led to defining STA approximations. Three definitions were proposed to represent STA as a series of modes: individual marker displacements, marker-cluster geometrical transformations (MCGT), and skin envelope shape variations. Modes were selected using two criteria: one based on modal energy and another on the selection of modes chosen a priori. The MCGT allows to select either rigid or non-rigid STA components. It was also empirically demonstrated that only the rigid component affects joint kinematics, regardless of the non-rigid amplitude. Therefore, a model of thigh and shank STA rigid component at cluster-level was then defined. An acceptable trade-off between STA compensation effectiveness and number of parameters can be obtained, improving joint kinematics accuracy.
The obtained results lead to two main potential applications: the proposed models can generate realistic STAs for simulation purposes to compare different skeletal kinematics estimators; and, more importantly, focusing only on the STA rigid component, the model attains a satisfactory STA reconstruction with less parameters, facilitating its incorporation in an pose estimator.
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Naaim, Alexandre. „Modélisation cinématique et dynamique avancée du membre supérieur pour l’analyse clinique“. Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1014/document.
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Les Artefacts de Tissus Mous (ATM) sont actuellement une des limitations principales pour la mesure du mouvement du membre supérieur avec les techniques actuelles d'analyse du mouvement. L'optimisation multi-segmentaire (OMS) a déjà prouvé son efficacité pour la mesure du mouvement du membre inférieur. Afin d'avoir la meilleure correction possible, il est nécessaire d'utiliser des modèles d'articulation proches de l'anatomie. L'objectif de cette thèse a donc été de développer et de valider un modèle du membre supérieur qui pourrait être utilisé pour la correction des ATM par OMS. De nouveaux modèles en boucle fermée de l'avant-bras et de la ceinture scapulaire ont ainsi été développés accompagnés d'un nouveau modèle de l'articulation scapulo-thoracique imposant à la scapula d'être tangente à un ellipsoïde modélisant le thorax. Ces nouveaux modèles ont été confrontés aux modèles courants de la littérature à travers une étude avec vis intra-corticales sur cadavre et in vivo sur sujets asymptomatiques. Des niveaux d'erreur similaires ont été observés pour tous les modèles quant à leur capacité de corriger les ATM et d'imiter la cinématique osseuse. Les nouveaux modèles semblent cependant beaucoup plus intéressants dans une perspective de développement d'un modèle musculo- squelettique. En effet, le modèle d'avant-bras autorise à la fois d'avoir le mouvement du radius et de l'ulna tandis que le modèle scapulo-thoracique représente mieux la contrainte existant entre le thorax et la scapula. En résumé, cette thèse a permis de développer un modèle complet proche de l'anatomie du membre supérieur permettant de corriger les ATM en utilisant une OMS. Bien que la correction des ATM obtenue n'est pas aussi satisfaisante qu'espérée, l'utilisation de cette approche pour le développement de futurs modèles musculo-squelettique a été validéeSoft Tissue Artefact (STA) is one of the most important limitations when measuring upper limb kinematics through marker-based motion capture techniques, especially for the scapula. Multi Body Optimisation (MBO) has already been proposed to correct STA when measuring lower limb kinematics and can be easily adapted for upper limb. For this purpose, the joint kinematic constraints should be as anatomical as possible. The aim of this thesis was thus to define and validate an anatomical upper limb kinematic model that could be used both to correct STA through the use of MBO and for future musculoskeletal models developments. For this purpose, a model integrating closed loop models of the forearm and of the scapula belt have been developed, including a new anatomical-based model of the scapulothoracic joint. This model constrained the scapula plane to be tangent to an ellipsoid modelling the thorax. All these models were confronted to typical models extracted from the literature through cadaveric and in vivo intracortical pins studies. All models generated similar error when evaluating their ability to mimic the bones kinematics and to correct STA. However, the new forearm and scapulothoracic models were more interesting when considering further musculoskeletal developments: The forearm model allows considering both the ulna and the radius and the scapulothoracic model better represents the constraint existing between the thorax and the scapula. This thesis allowed developing a complete anatomical upper limb kinematic chain. Although the STA correction obtained was not as good as expected, the use of this approach for a future musculoskeletal models has been validated
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Lahkar, Bhrigu. „Contribution à la modélisation musculosquelettique personnalisée du membre inférieur par éléments finis“. Thesis, Paris, HESAM, 2020. http://www.theses.fr/2020HESAE070.
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Le trouble musculosquelettique du membre inférieur est l'un des fardeaux de santé les plus courants pouvant entraîner une déficience fonctionnelle chez un individu. Bien que diverses options de gestion opérationnelle soient disponibles, il ne semble pas y avoir unanimité sur une procédure particulière qui servirait au mieux les intérêts de tous. Pour évaluer objectivement les troubles et planifier efficacement les interventions chirurgicales, il est essentiel de comprendre la biomécanique des membres inférieurs dans des conditions de charge physiologique. Avec cette motivation, ce travail de thèse vise à développer un cadre complet de modélisation musculosquelettique du membre inférieur basé sur les éléments finis. La première phase du travail de thèse est axée sur le développement et l'évaluation de modèles personnalisés d'éléments finis en flexion passive. De nouvelles approches sont proposées et évaluées pour le développement rapide de modèles axés sur la géométrie et les propriétés des ligaments. Dans la deuxième phase, une nouvelle approche basée sur les éléments finis pour la compensation des artefacts des tissus mous est proposée et évaluée. Cette contribution a permis de compenser efficacement les artefacts des tissus mous dans l'analyse du mouvement en tenant compte de la spécificité du sujet. La troisième phase du travail de thèse est consacrée à l'application clinique, où l'utilité du système radiographique biplan dans l'évaluation de l'alignement des implants de l'arthroplastie totale du genou est brièvement explorée. Dans l'ensemble, ce travail de thèse peut aider à estimer et à comprendre avec précision la biomécanique des membres inférieurs dans des conditions de charge cliniquement pertinentes, et à rapprocher le modèle de la routine cliniqueMusculoskeletal disorder of the lower limb is one of the most common health burdens that may lead to functional impairment in an individual. Although various operative management options are available, there seems no unanimity on a particular procedure that serves the best. To objectively assess disorders and effectively plan surgeries, it is essential to understand lower limb biomechanics under physiological loading conditions. With that motivation, this PhD aims to develop a comprehensive finite element based musculoskeletal modeling framework of the lower limb. The first phase of the PhD focuses on the development and evaluation of subject-specific finite element models under passive flexion. Novel approaches are proposed and evaluated for fast model development focusing on geometry and ligament properties. In the second phase, a novel finite element based approach for soft tissue artifact compensation is proposed and evaluated. This contribution allowed to effectively compensate for soft tissue artifact in motion analysis by taking subject specificity into account. The third phase of the PhD is dedicated to clinical application, where the utility of the biplanar X-ray system in evaluating Total Knee Arthroplasty implant alignment is briefly explored. Overall, this PhD may help to accurately estimate and understand lower limb biomechanics under clinically relevant loading conditions, and bring the model a step closer to clinical routine
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Li, Jia-Da, und 李佳達. „Development of 2D-3D Registration Methods for Alternating Biplane Fluoroscopy to Quantify Soft Tissue Artefacts in the Lower Limb and Their Effects on Mechanical Analysis of the Knee During Pedalling“. Thesis, 2018. http://ndltd.ncl.edu.tw/handle/3ws4gv.
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博士國立臺灣大學
醫學工程學研究所
106
Soft tissue artefacts (STA) have been recognized as a major source of error as applying stereophotogrammetry for human movement analysis. It not only affects the measurement of cycling motion but also limits interpretation of the results from the stereophotogrammetry-based measurement system. Currently, study of STA absent detailed, substantial results which provide guidelines for properly interpret results of cycling. 2D-3D subject-specific model-based registration method combined with biplane fluoroscopy is considered as a non-invasive accurate measurement method. However, the technique design for alternating exposures used in clinical system is not been proposed yet. Therefore, the study aims to develop 2D-3D registration methods for alternating biplane fluoroscopy and used to quantify soft tissue artefacts in the lower limb and their effects on mechanical analysis of the knee during pedalling. A tri-alternating images registration method is proposed combined with three kinematic models (constant speed, rigid and quasi-rigid) which help to predict bone pose of the adjacent frame under sole biplane fluoroscopy or combined with assistant measurement system conditions. The methods were verified by a cadaver study. Compare to single plane and pseudo biplane registration results, fast correction algorithm based on constant speed model already decreased 89% of out-of-plane errors and the target registration error eventually less than 0.7 mm. Performance of three models were comparable to the synchronized biplane registration. The rigid kinematic model was adopted for subsequence in vivo STA quantification during pedalling. Compare to the shank markers, the thigh markers showed greater STA and were affected more by pedal resistance. The STA varied with angles of the adjacent joints, largely linearly for shank markers while non-linearly for thigh markers. Markers near a joint experienced greater ranges of STA than mid-segment markers, but tended to have smaller variation. To estimate bone pose, STA produce greater rigid translations and rotations than the nonrigid component. Range of norigid component may not able to represent accuracy of the marker cluster used to estimate bone pose. On mechanical analysis, calculated joint angles were not affected by different resistant condition. Hybrid two marker clusters to estimate bone orientation and position separately help to reduce error of calculated joint angles and moments. The method developed in the study help to apply clinical sytem for measuring accurate bone kinematics. Results of STA during pedalling help other cycling study and the experiment data will be useful for the further studies.
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Peters, Alana Victoria. „Gait analysis methods to minimise soft tissue artefact and evaluate techniques to locate the hip joint centre“. 2010. http://repository.unimelb.edu.au/10187/8511.
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The purpose of this thesis was to investigate gait analysis methods used to minimise soft tissue artefact (STA) when measuring the kinematics and kinetics of human gait. STA affects all gait analysis methods and is considered to be one of the major sources of error in clinical motion analysis. A systematic review was initially performed to quantify the magnitude of STA for different areas of the lower limbs during gait analysis. Despite the high quality of the existing literature, the results of the review were inconclusive regarding the exact magnitude of STA during human gait analysis. Previously, there were no methods used consistently throughout the reviewed studies to assess STA. The primary aim of this thesis was to determine the most valid method for minimising STA during human gait analysis.Whilst the systematic review provided equivocal results on the magnitude of STA, it was able to confirm that STA at the tibia is less than for the femur segment. As a result, the tibial segment was investigated to determine marker locations that are least susceptible to STA. Twenty unimpaired young adults were included in the study and were instrumented with 36 markers, including 10 markers on each shank segment. The markers were well spread across the tibial segment in order to assess as many locations as possible. Four markers located on the tibia were less susceptible to STA. These were the proximal and distal anterior tibial crest markers as well as the medial and lateral malleolar markers. These markers were rigid to one another thus were rigid to the underlying bone.
In order to assess the modelling methods proposed in the literature a gold standard comparison was required. A potential new gold standard method was identified as 3-D freehand ultrasound (3-DUS). This was believed to be a non-invasive and cost effective method for locating internal bony structures. A validation of the new method (3-DUS) against MRI was performed to ensure the new gold standard was a valid methodology. The two methods, 3-DUS and MRI were compared for their accuracy in determining the location of the HJC within the pelvis segment. Twenty unimpaired participants were included in this study. The participants were of variable ages and physical composition. The difference between 3-DUS and MRI determined distance between the left and right HJC was 4.0 ± 2.3mm. It was determined that the results from 3-DUS were clinically not significantly different to MRI. The results of this investigation indicated that 3-DUS could be used as a gold standard measurement for three dimensional gait analysis (3-DGA) research.
The new gold standard method was used to validate existing 3-DGA modelling methods to determine which obtained the most accurate location of the HJC. To date, the greatest clinical application for gait analysis is as a test for people with central nervous system disorders associated with spasticity, especially children with cerebral palsy (CP) (Simon 2004). For this reason, 53 patients with gait abnormalities who had been referred to the Royal Children’s Hospital gait laboratory for a 3-DGA were tested. The participant sample represented patients who were referred to the Hugh Williamson Gait Analysis Laboratory (HWGAL). This was apparent because from 2008-2009 69% of patients at HWGAL had a diagnosis of CP, of the sample included in this study, 67% had a CP diagnosis.
Patients underwent a 3-DGA in addition to a 3-DUS of their left and right femoral heads. Resultant ultrasounds were assessed for the quality of the images and 46 patients were included for data analysis. Seven different methods were investigated for the determination of the HJC and four of these were analysed in two different ways, as such there were 11 models compared to 3-DUS. The Harrington et al method obtained the most accurate and repeatable results where the 3-D location error was 14.3 ± 8.0mm. That method considerably outperformed the functional techniques that had previously been proposed in the literature. This highlighted the importance of testing research techniques in target populations.
To conclude, this thesis has identified locations on the tibia which are most rigid to the underlying bone as well as a new gold standard measurement tool suitable for use in 3-D gait analysis research. The thesis has also demonstrated the validity of using functional methods for determining the HJC in pathological populations. Limitations of previous research were identified, including a lack of translation of research findings into clinical practice. Future work following on from this thesis should aim to address this issue.
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Silva, Liliana Sofia de Aguiar Pereira de. „Biomechanical models of the lower limb and pelvis, for female human gait in regular and overload conditions related to pregnancy“. Doctoral thesis, 2014. http://hdl.handle.net/10400.5/8340.
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Doutoramento em Motricidade Humana na especialidade de BiomecânicaA gravidez é uma fase especial da vida , considerando as adaptações morfológicas, fisiológicas, biomecânicas e hormonais vivenciadas pelas mulheres durante cerca de 40 semanas e no período pós-parto, podendo modificar o padrão de marcha e contribuir para uma sobrecarga no sistema músculo-esquelético, causando dor nos membros inferiores, bacia e zona lombar. Os objetivos do presente trabalho foram: 1) analisar a marcha de mulheres grávidas no segundo trimestre; 2) comparar as adaptações biomecânicas da marcha, entre as mulheres grávidas no segundo trimestre, mulheres não grávidas e mulheres com condições de sobrecarga artificiais; 3) analisar modelos biomecânicos com quatro set ups diferentes de análise; e, 4) analisar um modelo de contacto que determina a força vertical de reação do apoio. Os resultados demonstraram que as mulheres grávidas têm uma padrão de marcha similar ao normal. Observou-se que o ganho do peso no tronco aumenta o tempo das fases de apoio e de duplo apoio, quer nas mulheres grávidas quer nas mulheres com carga adicional. A resposta ao momento externo flexor da anca está relacionada com maior atividade dos extensores para suportar a carga anterior do tronco na direção da translação do centro de massa. Nas mulheres grávidas, o modelo universal-revolução-esférica afetou mais as variáveis cinemáticas quando comparado com o modelo de juntas com seis graus de liberdade. O modelo de contacto entre o pé e o solo, sobrestimou as forças verticais de reação. O aumento da massa do pé, devido ao inchaço consequente da gravidez, reduz a rigidez durante a fase de apoio. Os resultados do presente trabalho serão úteis para promover a investigação biomecânica do padrão de marcha durante a gravidez.
FCT - Fundação para Ciência e a Tecnologia
Buchteile zum Thema "Soft tissue artefacts"
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Prieto, Claudia, René M. Botnar, Hajime Sakuma, Masaki Ishida und Marcus R. Makowski. „Coronary imaging“. In The EACVI Textbook of Cardiovascular Magnetic Resonance, herausgegeben von Massimo Lombardi, Sven Plein, Steffen Petersen, Chiara Bucciarelli-Ducci, Emanuela R. Valsangiacomo Buechel, Cristina Basso und Victor Ferrari, 164–76. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198779735.003.0019.
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Due to its high soft tissue contrast, high spatial resolution, and lack of ionizing radiation, cardiovascular magnetic resonance (CMR) is a promising imaging modality for non-invasive imaging of the coronary arteries. However, because of the high spatial resolution and large coverage required for visualization of the coronary arteries, scan times are relatively long. This can result in imaging artefacts from cardiac and respiratory motion. Usually, coronary CMR is therefore performed with respiratory and cardiac compensation methods. CMR has shown promising results for the detection of coronary stenosis, when compared against invasive and computed tomography coronary angiography, but in clinical practice, CMR is more often used to define the course of anomalous coronary arteries and for the detection and tracking of coronary artery aneurysms. CMR also allows imaging of the coronary vessel wall and coronary plaque imaging, as well as the detection of coronary thrombus. These emerging methods may have a future role in risk stratification of patients with known or suspected coronary artery disease.
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Linney, Alf, João Campos und Ghassan Alusi. „Reconstruction of a 3D Mummy Portrait from Roman Egypt“. In Images and Artefacts of the Ancient World. British Academy, 2005. http://dx.doi.org/10.5871/bacad/9780197262962.003.0016.
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This chapter focuses on the reconstruction of the portrait mummy of Hermione, which was excavated in 1911. Hermione lived during the reign of the Roman emperor Tiberius and belonged to the Greek immigrants of ancient Egypt who were descendants of the soldiers who have fought Alexander the Great and the Ptolomies. Hermione is believed to have been a school teacher, as her coffin portrait bears the Greek inscription ‘Hermione grammatike’. To reconstruct the face of Hermione, x-ray imaging processes were first employed to gain vital information without moving the painted cartonnage and wrappings of the mummy. Computed tomography and CT scanning technology was also used to provide a measurement of the 3D distribution of x-ray absorption coefficients throughout the scanned volume. This more advanced form of scanning allowed for the creation of 3D reconstruction of the volume. For the 3D reconstruction of the face of Hermione, four methods were necessary. These were the acquisition of 3D data on what lies inside the wrappings, the 3D reconstruction of the skull, the reconstruction of the soft tissues over the skull, and the application of texture to the reconstructed facial surface.
Konferenzberichte zum Thema "Soft tissue artefacts"
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Jing, Xu, Shiguang Qiu und Xiumin Fan. „Real time human motion compensation based on joint DoF constraints for upper limb soft tissue artefacts“. In 2013 6th International Conference on Biomedical Engineering and Informatics (BMEI). IEEE, 2013. http://dx.doi.org/10.1109/bmei.2013.6746951.
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2
Rouhandeh, Azadeh, Chris Joslin, Zhen Qu und Yuu Ono. „Non-invasive assessment of soft-tissue artefacts in hip joint kinematics using motion capture data and ultrasound depth measurements“. In 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE, 2014. http://dx.doi.org/10.1109/embc.2014.6944585.
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Akbarshahi, Massoud, Justin W. Fernandez, Anthony Schache, Richard Baker, Scott Banks und Marcus G. Pandy. „Quantifying the Spatial Variation of Lower-Limb Soft Tissue Artefact During Functional Activity Using MR Imaging and X-Ray Fluoroscopy“. In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206538.
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Non-rigid movement of the soft tissue interface between skin-mounted markers and the underlying bones, also known as soft tissue artifact (STA), poses a major limitation to the non-invasive estimation of joint kinematics using three-dimensional (3D) motion analysis systems. Thorough knowledge of the nature of this non-rigid behavior is essential for development of compensation algorithms to enhance the accuracy of these systems. The studies in the literature aimed at quantifying STA have implemented invasive measurement methods such as bone pins [1] and external fixator devices [2], or have used subjects with pathological conditions [3]. In the present study, we integrated Magnetic Resonance (MR) and X-ray imaging techniques to evaluate the non-rigid behavior of the lower-limb soft tissue of healthy adults for a number of different functional tasks.
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Rouhandeh, Azadeh, und Chris Joslin. „Soft-tissue Artefact Assessment and Compensation in Motion Analysis by Combining Motion Capture Data and Ultrasound Depth Measurements“. In International Conference on Computer Vision Theory and Applications. SCITEPRESS - Science and Technology Publications, 2018. http://dx.doi.org/10.5220/0006624205110521.
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