Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-09T16:37:05Z No. of bitstreams: 1 jescaneftalinogueirasilva.pdf: 1568191 bytes, checksum: f265e2e8c149f785a2db409c3d85c37c (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2015-12-10T13:58:43Z (GMT) No. of bitstreams: 1 jescaneftalinogueirasilva.pdf: 1568191 bytes, checksum: f265e2e8c149f785a2db409c3d85c37c (MD5) / Made available in DSpace on 2015-12-10T13:58:44Z (GMT). No. of bitstreams: 1 jescaneftalinogueirasilva.pdf: 1568191 bytes, checksum: f265e2e8c149f785a2db409c3d85c37c (MD5) Previous issue date: 2015-04-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo no presente estudo foi avaliar a espessura da tábua óssea vestibular e do tecido gengival na região de incisivos superiores, em imagens de tomografia computadorizada de feixe cônico (TCFC), obtidas com e sem afastador labial. Tratase de um estudo clínico-tomográfico em que foram coletados dados da espessura da tábua óssea e gengiva vestibular de 120 incisivos superiores. Em exames de TCFC, obtidos com e sem afastador labial, foram realizadas medidas de espessuras óssea e gengival em diferentes regiões. Para validar a utilização da TCFC na mensuração do tecido gengival, medidas tomográficas foram correlacionadas com as medidas obtidas por sondagem clínica. As imagens com e sem afastador foram ainda comparadas em relação a sua qualidade. A medida de espessura óssea localizada na porção mais cervical (1 mm acima da crista óssea) apresentou uma média superior para os exames realizados com afastador labial (teste t pareado/ p = 0,021). As medidas de espessura da tábua óssea apresentaram correlações significativas com as espessuras do tecido gengival (correlação de Pearson/ p ≤ 0,02). O tecido gengival pode ser mensurado apenas em exames de TCFC obtidos com afastador labial, e as espessuras gengivais obtidas em TCFC apresentaram correlações significativas com aquelas obtidas clinicamente (correlação de Pearson/ p ≤ 0,001). Em relação à preferência dos avaliadores, 76% dos radiologistas e 56% dos implantodontistas preferiram as imagens obtidas com o afastador. Concluiu-se que a utilização de afastadores labiais durante a obtenção de exames de TCFC é uma técnica simples e confiável, que permitiu, além da avaliação do tecido ósseo, a mensuração dos tecidos gengivais. / The aim of this study was to evaluate the thickness of the buccal bone and the gingival tissue in the region of upper incisors by using computed tomography cone beam (CBCT), obtained with or without lip retractor. This is a clinical-tomographic study, in which the thickness of the buccal bone and gingiva were collected from 120 upper incisors. Bone and gingival thickness, with and without lip retractor, were measured in different regions of CBCT images. To validate the use of CBCT for measuring gingival tissue, the tomographic measurements were correlated with data acquired by clinical probing. The images with or without lip retractor were also compared regarding their quality. The bone thickness measurement located at the cervical portion (1 mm above the bone crest), was higher when lip retractor was employed (paired t-test/ p = 0.021). The thicknesses of the bone tissue were significantly correlated with those of the gingival tissue (Pearson correlation/ p ≤ 0.02). The gingival tissue could only be measured in CBCT scans obtained with lip retractor. The gingival thickness from CBCT showed significant correlations with those obtained clinically (Pearson correlation/ p ≤ 0.001). Regarding the preference of the evaluators, 76% of radiologists and 56% of implant specialists preferred the images obtained with the lip retractor. It was concluded that in addition to the classical bone tissue examination, the use CBCT with lip retractor is a simple and reliable technique for measuring the gingival tissues.

The human face is not perfectly symmetrical, slight asymmetries commonly occur in every individual across all populations. The aim of the work was to monitor the asymmetry on the entire surface of the soft and hard tissues of the heads of individuals with respect to age and sexual dimorphism. The follow-up goal was then to evaluate the difference in asymmetry between the tissues. The material for the work was a transverse set of CT images of the adult Czech population in the age range of 21-84 years. Individuals were divided according to gender into 50 men and 48 women and according to age into groups up to 39 years, 40-59 years and over 60 years. Geometric morphometry methods (CPD - DCA, asymmetry analysis, per vertex T-test, superprojection methods) were used for data analysis. The results were visualized using color maps and significance maps that show asymmetry and statistical significance. The variability of the file was analyzed by principal component analysis. The results of the evaluation of hard tissues showed a right protrusion on the anterior and lateral surfaces of the skull, in both men and women at all age intervals. This asymmetry was statistically very significant, in contrast to the posterior region, which was evaluated protrusion on the left side and had lower p-value. On the soft...

This study provides an overview of the implementation of a nonlinear microstructural constitutive model in ABAQUS employing a user subroutine at the level of the biomedical engineer. Two different element formulations are employed: a continuum incompressible and a plane stress incompressible. All examples are validated by performing a number of deformations on 2D and 3D square elements and comparing the analytical formulation in a programming language and the user subroutine in ABAQUS. Application models will be presented that provide a deeper look into the impacts of soft tissue deformation, damage, and fracture. Additionally, we investigate the mechanical behavior of skin layers in terms of the nominal stress-strain curve using uniaxial and cyclic loading tests on porcine skin specimens in two forms: dermis integrating epidermis and hypodermis. Experiments were performed on specimens from the belly and breast of the pigs and under both orthogonal orientations with respect to the spine direction. All tests were carried out at room temperature with cyclic loading at a constant strain rate and increasing stretch increments. Finally, data is fitted using microstructural constitutive model.

Os simuladores que empregam técnicas de Realidade Virtual são alternativas vantajosas às formas tradicionais de ensino e treinamento médico. Esses simuladores apresentam requisitos específicos, tais como: interação em tempo real e modelos realistas para representar órgãos e tecidos. Além disso, devem possuir comportamentos físicos suficientemente parecidos com os reais e gerar feedbacks dos procedimentos que estejam sendo simulados. Essas características exigem esforços de programação para o desenvolvimento de técnicas de interação e visualização 3D, além de estudos dos tecidos humanos, incluindo o comportamento físico dos órgãos e tecidos e o estudo das leis da Física envolvidas neste processo. O tema central desta pesquisa é a simulação de procedimentos de punção, sendo que nesse tipo de aplicações são necessários tanto o realismo visual como também o háptico, a fim de proporcionar ao usuário sensações parecidas com as encontradas nos procedimentos reais. Os métodos que utilizam parâmetros físicos são os mais utilizados alcançar o realismo exigido na interação háptica. No entanto, esses métodos deixam a desejar no que diz respeito à interação em tempo real. Dessa forma, o objetivo desta pesquisa foi desenvolver um novo método para simular a deformação de objetos tridimensionais que representam órgãos humanos. De forma que sejam alcançados o realismo visual, o realismo háptico e a interação em tempo real, com um custo computacional aceitável. O método desenvolvido consiste na divisão dos objetos tridimensionais em camadas, a fim de simular o volume e também a heterogeneidade dos órgãos humanos. O número de camadas e a atribuição de parâmetros físicos podem ser definidos de acordo com os diferentes tecidos que compõem o órgão humano e respectivos comportamentos que se pretenda simular. O método foi desenvolvido depois de conduzida uma Revisão Sistemática para levantamento dos métodos utilizados em aplicações para treinamento médico e respectivos níveis de realismo visual e háptico oferecidos. Para demonstrar e testar o funcionamento do método foi criado um simulador genérico de procedimentos de punção, no qual podem ser configurados o número de camadas, os parâmetros visco-elásticos, e assim permitir a avaliação do desempenho e o realismo das simulações. Como exemplo de aplicação o método foi aplicado em um simulador de punção de mama, cuja qualidade foi avaliada por médicos especialistas. Os protótipos foram criados no Laboratório de Tecnologias Interativas da Escola Politécnica da USP (Interlab), a partir de um Framework desenvolvido pelo Laboratório de Aplicações de Informática em Saúde da Escola de Artes Ciências e Humanidades da USP (LApIS). / Simulators that employ Virtual Reality techniques can prove to be an advantageous alternative to the traditional forms of medical learning and training. These simulators have specific requirements, such as real-time interaction and realistic models representing organs and tissues. Moreover, they should possess physical behavior similar enough to real life and generate feedback from procedures being simulated. These characteristics require programming efforts for the development of 3D visualization and interaction techniques, as well as studies of human tissue, including the physical behavior of organs and tissues and the study of the laws of Physics involved in this process. The main theme of this research is the simulation of puncture procedures. This type of application requires a realistic rendering of both visual and haptic traits in order to provide the user with sensations similar to those found in real procedures. Methods which employ physical parameters are more widely used to achieve the realism required in haptic interaction. However, these methods present shortcomings regarding real-time interaction. Thus, the aim of this research was to develop a new method to simulate the deformity of tridimensional objects that represent human organs and to achieve visual realism, haptic realism, and real-time interaction, with acceptable computational costs. The method developed in this study consists in dividing tridimensional objects into layers in order to simulate volume as well as heterogeneity of human organs. The number of layers and the attribution of physical parameters can be defined according to different tissues that compose the human organ and respective behaviors that one wishes to simulate. The method was developed after a systematic review to assess the methods employed in applications for medical training and their respective levels of visual and haptic realism. In order to demonstrate and to test how the method operates, we created a generic simulator of puncture procedures, which can be configured with any combination of layers of tissue and its viscoelastic parameters, allowing for the assessment of simulation performance and realism. As an example, the method was applied to a breast biopsy simulator whose quality was evaluated by specialist doctors. The prototypes were created in the Interactive Technology Laboratory (Interlab) of the Engineering School of the University of São Paulo, from a framework developed by the Laboratory of Computer Applications for Health Care (LApIS) of the School of Arts, Science and Humanities of the University of São Paulo.

Após a análise subjetiva utilizando fotografias de perfil de 540 indivíduos, selecionou-se 120 indivíduos adultos jovens (60 do gênero masculino e 60 do feminino), leucodermas, com perfil facial harmonioso, equilíbrio do terço inferior da face e selamento labial passivo, com o objetivo de estabelecer parâmetros cefalométricos para avaliar a estética facial e analisar as correlações entre referências anteroposteriores do tecido tegumentar da face. Utilizando telerradiografias dos indivíduos selecionados, foram desenhadas estruturas anatômicas de interesse e traçada a linha vertical passando pelo ponto sela (LSv) e linhas horizontais verdadeiras passando pelos pontos PRT (ponto de referência da fronte), Pn, A, Ls, Li, B e Pg. Os valores médios cefalométricos obtidos para o gênero masculino e feminino e o total da amostra foram submetidos aos testes estatísticos. As medidas cefalométricas avaliadas mostraram-se maiores no gênero masculino do que no feminino. No gênero masculino, todas as medidas cefalométricas do terço médio e inferior apresentaram correlação positiva estatisticamente significativa com a referência do terço superior da face e todas as correlações mostraram-se valores maiores que no feminino. No gênero feminino, não foram observadas correlações diretas estatisticamente significativas para as medidas Sv-B (p = 0,107) e Sv-Pg (p = 0,091). As fórmulas para a previsibilidade dos valores de Sv - Pn, Sv - A, Sv - Ls, Sv - Li, Sv - B e Sv - Pg para o gênero masculino e o feminino em função da medida Sv-PRT mostraram-se igual para ambos os gêneros, necessitando ser acrescido um valor compensatório a cada medida para os homens. / After subjective analysis of profile photographs of 540 individuals, 120 young adults (60 males and 60 females), leucodermas, with balanced facial profile, equilibrium of the lower facial third and passive lip sealing, in order to establish cephalometrics parameters for facial esthetics and evaluate the correlation between anteroposterior references of facial soft tissues. By using lateral radiographies of the selected individuals, anatomic structures of interesting were drawn, and the true vertical line passing through Sela point (LSv) and true horizontal lines passing through points PRT (reference point of the forehead), Pn, A, Ls, Li, B e Pg. The cephalometric average values which were calculated for masculine, feminine genders and the total of sample were evaluated by statics tests. The cephalometric measures analyzed showed high values to the masculine gender in comparing to the feminine gender. In the masculine gender, all the cephalometric measures of the middle and lower facial third presented positive correlation statistically significant to the reference of the superior facial third and all correlations were higher than female measures. In the feminine gender, direct correlations statistically significant for Sv-B (p = 0,107) e Sv-Pg (p = 0,091) measures. The formulas for the prevision of the values of Sv - Pn, Sv - A, Sv - Ls, Sv - Li, Sv - B e Sv - Pg dimensions for males and females individuals in function of Sv-PRT showed similar in both genders, needing to be added a specific value for each measures for males individuals.

Os simuladores que empregam técnicas de Realidade Virtual são alternativas vantajosas às formas tradicionais de ensino e treinamento médico. Esses simuladores apresentam requisitos específicos, tais como: interação em tempo real e modelos realistas para representar órgãos e tecidos. Além disso, devem possuir comportamentos físicos suficientemente parecidos com os reais e gerar feedbacks dos procedimentos que estejam sendo simulados. Essas características exigem esforços de programação para o desenvolvimento de técnicas de interação e visualização 3D, além de estudos dos tecidos humanos, incluindo o comportamento físico dos órgãos e tecidos e o estudo das leis da Física envolvidas neste processo. O tema central desta pesquisa é a simulação de procedimentos de punção, sendo que nesse tipo de aplicações são necessários tanto o realismo visual como também o háptico, a fim de proporcionar ao usuário sensações parecidas com as encontradas nos procedimentos reais. Os métodos que utilizam parâmetros físicos são os mais utilizados alcançar o realismo exigido na interação háptica. No entanto, esses métodos deixam a desejar no que diz respeito à interação em tempo real. Dessa forma, o objetivo desta pesquisa foi desenvolver um novo método para simular a deformação de objetos tridimensionais que representam órgãos humanos. De forma que sejam alcançados o realismo visual, o realismo háptico e a interação em tempo real, com um custo computacional aceitável. O método desenvolvido consiste na divisão dos objetos tridimensionais em camadas, a fim de simular o volume e também a heterogeneidade dos órgãos humanos. O número de camadas e a atribuição de parâmetros físicos podem ser definidos de acordo com os diferentes tecidos que compõem o órgão humano e respectivos comportamentos que se pretenda simular. O método foi desenvolvido depois de conduzida uma Revisão Sistemática para levantamento dos métodos utilizados em aplicações para treinamento médico e respectivos níveis de realismo visual e háptico oferecidos. Para demonstrar e testar o funcionamento do método foi criado um simulador genérico de procedimentos de punção, no qual podem ser configurados o número de camadas, os parâmetros visco-elásticos, e assim permitir a avaliação do desempenho e o realismo das simulações. Como exemplo de aplicação o método foi aplicado em um simulador de punção de mama, cuja qualidade foi avaliada por médicos especialistas. Os protótipos foram criados no Laboratório de Tecnologias Interativas da Escola Politécnica da USP (Interlab), a partir de um Framework desenvolvido pelo Laboratório de Aplicações de Informática em Saúde da Escola de Artes Ciências e Humanidades da USP (LApIS). / Simulators that employ Virtual Reality techniques can prove to be an advantageous alternative to the traditional forms of medical learning and training. These simulators have specific requirements, such as real-time interaction and realistic models representing organs and tissues. Moreover, they should possess physical behavior similar enough to real life and generate feedback from procedures being simulated. These characteristics require programming efforts for the development of 3D visualization and interaction techniques, as well as studies of human tissue, including the physical behavior of organs and tissues and the study of the laws of Physics involved in this process. The main theme of this research is the simulation of puncture procedures. This type of application requires a realistic rendering of both visual and haptic traits in order to provide the user with sensations similar to those found in real procedures. Methods which employ physical parameters are more widely used to achieve the realism required in haptic interaction. However, these methods present shortcomings regarding real-time interaction. Thus, the aim of this research was to develop a new method to simulate the deformity of tridimensional objects that represent human organs and to achieve visual realism, haptic realism, and real-time interaction, with acceptable computational costs. The method developed in this study consists in dividing tridimensional objects into layers in order to simulate volume as well as heterogeneity of human organs. The number of layers and the attribution of physical parameters can be defined according to different tissues that compose the human organ and respective behaviors that one wishes to simulate. The method was developed after a systematic review to assess the methods employed in applications for medical training and their respective levels of visual and haptic realism. In order to demonstrate and to test how the method operates, we created a generic simulator of puncture procedures, which can be configured with any combination of layers of tissue and its viscoelastic parameters, allowing for the assessment of simulation performance and realism. As an example, the method was applied to a breast biopsy simulator whose quality was evaluated by specialist doctors. The prototypes were created in the Interactive Technology Laboratory (Interlab) of the Engineering School of the University of São Paulo, from a framework developed by the Laboratory of Computer Applications for Health Care (LApIS) of the School of Arts, Science and Humanities of the University of São Paulo.

Many applications of ultrasound test phantoms require that the acoustical properties of the phantom should closely match those of soft tissue. Numerous commercial test phantoms of this type are available for use with clinical ultrasound scanners, which use frequencies up to 20 MHz. However, scanners designed for imaging small animals in preclinical studies, typically operate at much higher frequencies. No commercially available test phantoms exist for use at frequencies above 20 MHz. The aim of this work was to develop a tissue-mimicking-material (TMM) that closely matches the acoustic properties of small animal tissues at high frequencies (HF). Such a material would, therefore, be suitable for ultrasound test phantoms for application with HF ultrasound scanners (20 MHz to 50 MHz). A three-step approach was adopted to address this lack of a suitable HF-TMM. Firstly, verify the acoustic characteristics of the existing IEC agar-based TMM. Secondly, establish the acoustic properties (speed of sound and attenuation coefficient) of small animal tissue at high frequencies. Thirdly, develop a TMM which exhibits, as closely as possible, these small animal tissue acoustic characteristics. A pulse-echo substitution method was used throughout to characterise the materials and the tissue samples. The speed of sound and attenuation coefficient of an IEC agar-based TMM were measured using two different techniques. Initially, a widely used method was tried, where samples are wrapped in film and placed in degassed, deionised water for assessment. The second technique was developed and validated for use in this work. In this method, TMM samples were uncovered (without film) and were both stored and assessed in a TMM preserving fluid. The second method provided up to four times more consistent results. The acoustical properties of the individual components of the IEC agar-based TMM were then measured in order to determine whether the overall attenuation coefficient of the agar TMM was a linear sum of the attenuation coefficients of its component parts. Within experimental uncertainties, this was found to be the case. This is a key observation from which the formulation of an agar TMM, matching the acoustic properties of small animal tissue, can be facilitated. The acoustical properties (speed of sound and attenuation coefficient) of mouse brain, liver, and kidney were measured using a preclinical ultrasound scanner.

Chaque année en France, on dénombre environ 2000 cas de lésions de la région abdominale lors d'accidents de la route. Ces lésions sont très souvent sévères, mortelles dans 20% des cas, et nécessitent un traitement médical délicat, long et coûteux car il fait appel à la chirurgie dans un cas sur deux. Parmi ces lésions, celles du foie font partie des plus fréquentes mais aussi des plus graves à cause de leur risque hémorragique et sceptique élevé. Une voie d'amélioration de leur prévention passe alors par la conception de systèmes de protection plus efficaces basée sur une connaissance détaillée du comportement de ces structures et des mécanismes lésionnels mis en jeu lors d'un choc. L'objectif de ce travail a donc été de construire un outil numérique de prédiction des lésions hépatiques en situation d'impact. Pour cela, nous avons tout d'abord réalisé une étude expérimentale de compression uniaxiale de foies humains à différentes vitesses pour observer le comportement visco-hyperélastique du foie et comprendre ses modes de rupture tant à l'échelle globale qu'à l'échelle cellulaire. Ensuite, nous avons fixé un cadre théorique adapté à la fois au comportement observé et à la description de l'endommagement et de la rupture. Enfin, nous avons construit un modèle éléments finis intégrant une description fine des sous-structures du foie (parenchyme, capsule et arbres vasculaires), les comportements théoriques déduits de la phase expérimentale, la rupture des différents tissus et la présence de fluide dans les structures vasculaires. / Every year in France, about 2000 cases of abdominal injuries are due to car crashes. These injuries are often severe and 20% of them are lethal. They require long and expensive treatments because half of cases needs surgery. Among abdominal organs, liver is one of the most frequently and severely injured: haemorrhage and infectious risks are real. To improve hepatic injuries prevention, the definition of efficient safety devices should be based on a comprehensive knowledge of these structures behaviour and liver injury mechanisms. Thus the aim of this thesis was to build a predictive tool for hepatic injuries in crash situation. To achieve this point, we performed experimental uniaxial compressions of human livers with various loading speeds. We then observed the visco-hyperelastic behaviour of the liver and its failure modes at the global scale and also at the cells scale. After that, we chose a theoretical framework which was adapted both to the observed behaviour and to the damage and rupture description. We finally built a finite element model which integrate a precise description of liver structures (parenchyma, capsule and vascular trees), the theoretical behaviours deduced from the experimental phase, the failure of the different tissues and the fluid action within the vascular structures. After the model calibration and validation with experimental observations, this FEM makes up the wanted predictive tool for hepatic injuries. This tool can be used both with slow and rapid loading speeds.

Cette thèse s’inscrit dans la démarche de caractérisation mécanique des tissus mous du vivant in situ et in vivo par un dispositif de succion utilisable en salle opératoire. L’objectif est de fournir au chirurgien un outil simple, efficace, et si possible de coût réduit, pour estimer les propriétés mécaniques spécifiques au patient et en temps réel afin guider leur décisions. Malheureusement, les structures biologiques sont souvent hétérogènes due à leur composition (peau, muqueuse, fibres musculaires, matière adipeuse, fascias, vascularisation, …). En particulier, ces structures biologiques présentent un gradient de propriétés mécanique dans la profondeur. Il s’agit donc de répondre à un problème complexe, d’autant plus qu’il est nécessaire de proposer une méthode non destructive adaptée à une mesure in situ et in vivo en salle opératoire.Parmi les procédés de caractérisation mécanique rencontrés, les méthodes basées sur la succion sont courantes. Ce procédé de mesure consiste à aspirer un volume de tissu mou à travers une ouverture en mesurant simultanément la pression et la hauteur de tissu dans l’enceinte. Une procédure d’identification inverse est ensuite mise en place pour identifier les propriétés mécaniques du tissu. Cette mesure de hauteur étant généralement effectuée à l’aide d’une caméra, le design des systèmes rencontrés reste cependant délicat, en particulier pour respecter les contraintes d’encombrement et de stérilisation des systèmes.Au cours de ce travail, la méthode d’aspiration a été revisitée en remplaçant la mesure de hauteur par une mesure de volume. L’extrémité du dispositif d’aspiration se réduit maintenant à un simple tube : le système fourni est donc facilement stérilisable, le diamètre et la géométrie de l’ouverture peuvent être choisis en fonction des objectifs des mesures à effectuer. Il semble donc difficile d’imaginer un système plus simple, d’encombrement plus réduit et de coût inférieur à celui-ci.Plusieurs problématiques ont été étudiées autour de ce nouveau système :les précisions de mesures obtenues par volume ou, plus classiquement, par caméra ont été confrontées. Au bilan, la mesure de volume présente un ratio signal/bruit similaire ou inférieur aux mesures de volume obtenues par caméra. L’impact de différents paramètres expérimentaux a été évalué et quantifié, permettant d’optimiser la qualité des mesures.les résultats d’identification inverse ont été validés sur des échantillons en silicone. Leur matériau constitutif a été caractérisé pour référence en traction uniaxiale et par bulge test. Les modules de Young obtenus par identification inverse sur le test d’aspiration (calcul itératif par Elements Finis) montrent une sur-estimation de 7% au maximum avec les résultats des tests de référence. Ce résultat est une amélioration significative par rapport aux sur-estimations de 30% rencontrées dans la littérature.les caractéristiques du système ont été mises à profit pour mesurer directement l’épaisseur et les propriétés mécaniques de couches superficielles de tissus multicouches sans autre système de mesure. La preuve de concept a été effectuée expérimentalement sur un échantillon artificiel constitué de deux silicones différents. Au bilan, l’épaisseur de la couche supérieure a été identifiée avec une erreur inférieure à 4% , les modules de Young des deux matériaux avec une erreur inférieure à 8%. Ces résultats sont jugés très encourageants pour une future application de la méthode à des tissus du vivant.une méthode d’identification inverse des propriétés mécaniques en temps réelle a été développée. Cette procédure est basée sur une réduction de modèle et fournit également des indications sur la sensibilité de l’identification aux différents paramètres expérimentaux. L’utilisation de cette méthode d’inversion a montré une erreur d’identification de 10 et 12% par rapport aux valeurs de références sur les spécimens constitués de deux couches de silicones. / In-vivo characterization of biological soft tissues is a key step toward patient-specific biomechanical simulation and planning of intra-operative assisted surgery. These tissues’ structures are usually highly heterogeneous due to the variety of their constituents (skin, mucosa, muscle fibers, fat, fascia, vascularization, etc.). In particular, their local mechanical properties may change with depth.Among various characterization techniques, aspiration method is a standard due to its simplicity: tissue is aspirated through a hole while measuring the negative pressure and the associated apex height. An inverse problem is then solved to identify the material mechanical properties. In the literature, the apex height was usually measured using a camera, which induced design difficulties, in particular regarding the required sterilization process for in-vivo measurements.This thesis aims at developing new practical aspiration techniques and inverse analyze techniques to deal with these challenges.First, the aspiration method is revisited, replacing the apex height optical measurement by the measurement of the aspirated tissue volume. In the proposed method the system head was reduced to a simple tube: sterilization becomes easy and the aspiration aperture diameter can be changed according to experimental requirements. The proposed system is thus probably among the simplest, lightest and most inexpensive devices one could achieve.Then, many studies are developed: (i) a comparison of this volume-based method with classical techniques based on optical measurements, (ii) the validation of the volume-based aspiration device and inverse identification on soft homogeneous synthetic materials, (iii) the development of a method for in-vivo identification of multi-layered soft tissues and its validation on two-layer synthetic samples, and (iv) a method for real-time inverse mechanical identification of constitutive materials using the aspiration results.The experimental signal-to-noise ratio in raw volume measurements obtained either optically or by the volume-based method were compared. The effects on the accuracy of various experimental parameters were investigated and quantified: the volume measurement was proved to present the same order or even better accuracy compared to optical measurements.To validate the inverse identifications using the volume-based aspiration method, silicone samples were then made and characterized using (1) aspiration, and, as references, two standard tests such as (2) uniaxial and (3) equibiaxial extension tests. Performing a Finite Element (FE) inverse identification on the experimental results provided Young’s moduli similar to classical tests with about 7% maximum overestimation for the silicones. This underlines a significant improvement of the measurement method accuracy compared to the literature (about 30% relative overestimation).In the proposed device, the aspiration aperture diameter can be easily changed. This feature was used to develop a new method to characterize the mechanical properties as well as the superficial layers’ thicknesses in multi-layer soft tissues. A proof of concept was experimentally validated on two-layer artificial soft silicone specimens. As a conclusion, the superficial layer thicknesses and the materials Young’s moduli were identified with a maximum error of 4 and 8%, respectively. Such results thus provide encouraging perspectives for the in-vivo characterization of two-layer anatomical structures such as skin and sub-dermal tissues.Eventually, a Design Of Experiment (DOE) method was applied to drastically decrease the computation time involved during the inverse identification step, which is a prerequisite for any use in a clinical routine. The identifications using the DOE method were compared with the reference characteristics of the investigated silicones and maximum errors of 10 and 12% were obtained for the homogeneous and two-layer samples, respectively.

Após a análise subjetiva utilizando fotografias de perfil de 540 indivíduos, selecionou-se 120 indivíduos adultos jovens (60 do gênero masculino e 60 do feminino), leucodermas, com perfil facial harmonioso, equilíbrio do terço inferior da face e selamento labial passivo, com o objetivo de estabelecer parâmetros cefalométricos para avaliar a estética facial e analisar as correlações entre referências anteroposteriores do tecido tegumentar da face. Utilizando telerradiografias dos indivíduos selecionados, foram desenhadas estruturas anatômicas de interesse e traçada a linha vertical passando pelo ponto sela (LSv) e linhas horizontais verdadeiras passando pelos pontos PRT (ponto de referência da fronte), Pn, A, Ls, Li, B e Pg. Os valores médios cefalométricos obtidos para o gênero masculino e feminino e o total da amostra foram submetidos aos testes estatísticos. As medidas cefalométricas avaliadas mostraram-se maiores no gênero masculino do que no feminino. No gênero masculino, todas as medidas cefalométricas do terço médio e inferior apresentaram correlação positiva estatisticamente significativa com a referência do terço superior da face e todas as correlações mostraram-se valores maiores que no feminino. No gênero feminino, não foram observadas correlações diretas estatisticamente significativas para as medidas Sv-B (p = 0,107) e Sv-Pg (p = 0,091). As fórmulas para a previsibilidade dos valores de Sv - Pn, Sv - A, Sv - Ls, Sv - Li, Sv - B e Sv - Pg para o gênero masculino e o feminino em função da medida Sv-PRT mostraram-se igual para ambos os gêneros, necessitando ser acrescido um valor compensatório a cada medida para os homens. / After subjective analysis of profile photographs of 540 individuals, 120 young adults (60 males and 60 females), leucodermas, with balanced facial profile, equilibrium of the lower facial third and passive lip sealing, in order to establish cephalometrics parameters for facial esthetics and evaluate the correlation between anteroposterior references of facial soft tissues. By using lateral radiographies of the selected individuals, anatomic structures of interesting were drawn, and the true vertical line passing through Sela point (LSv) and true horizontal lines passing through points PRT (reference point of the forehead), Pn, A, Ls, Li, B e Pg. The cephalometric average values which were calculated for masculine, feminine genders and the total of sample were evaluated by statics tests. The cephalometric measures analyzed showed high values to the masculine gender in comparing to the feminine gender. In the masculine gender, all the cephalometric measures of the middle and lower facial third presented positive correlation statistically significant to the reference of the superior facial third and all correlations were higher than female measures. In the feminine gender, direct correlations statistically significant for Sv-B (p = 0,107) e Sv-Pg (p = 0,091) measures. The formulas for the prevision of the values of Sv - Pn, Sv - A, Sv - Ls, Sv - Li, Sv - B e Sv - Pg dimensions for males and females individuals in function of Sv-PRT showed similar in both genders, needing to be added a specific value for each measures for males individuals.