Made available in DSpace on 2014-06-11T19:31:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-22Bitstream added on 2014-06-13T18:06:53Z : No. of bitstreams: 1 zanatta_r_dr_jabo.pdf: 28419186 bytes, checksum: 99fc23beed288698b72ece9e5547815c (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A proposta deste estudo foi estabelecer um método de ensino para a disciplina de diagnóstico por imagem veterinária, ao associar o uso de imagens tridimensionais às aulas convencionais de radiologia. Para este fim foram obtidas imagens tridimensionais, por meio de exames de tomografia computadorizada multidetectores, da cabeça de cinco gatos domésticos. Estas imagens foram adicionadas à aula de radiologia da cabeça, onde comumente são apresentadas imagens bidimensionais. A aula foi ministrada para alunos de três instituições de ensino superior, uma federal, uma estadual e outra particular. Após a apresentação, os alunos responderam a um questionário para que fosse possível verificar se o método contribuiu para assimilar com mais facilidade o conhecimento anatômico e radiográfico regional. Dos 100 alunos, 77% acharam o método totalmente satisfatório, 19% satisfatório, 2% moderadamente satisfatório, 2% pouco satisfatório. Nenhum aluno considerou o método insatisfatório, validando o método proposto. Como objetivo secundário discutiram-se as imagens tridimensionais obtidas, com enfoque anatomo-clínico, visando tornar mais atrativo o estudo da anatomia radiográfica dos ossos da cabeça. As imagens permitiram a identificação dos ossos e das cavidades da cabeça. Acredita-se que estas possam ser utilizadas no estudo das estruturas frequentemente acometidas por enfermidades em gatos domésticos / The aim of this study was to establish a teaching methodology for diagnostic imaging in veterinary medicine by correlating the use of three-dimensional images to conventional radiology lectures. For this purpose, threedimensional images of the head of five domestic cats were acquired by multi-detector row computed tomography. These images were added to the lecture of radiology of the head, in which two-dimensional images are usually presented. The lecture was presented to students of three different institutions (federal, state and private). After the lecture the students answered a questionnaire to verify if the method contributed for better assimilation of the anatomical and radiographic knowledge. From 100 students, 77% found the method highly satisfactory, 19% satisfactory, 2% moderately satisfactory, 2% poorly satisfactory. None of the students found the method unsatisfactory. Threedimensional images obtained had been discussed with an anatomical and clinical view to make the study of radiographic anatomy of the bones of the head more attractive to students. The images allowed the identification of bones and cavities of the head, being able to be used to study the structures that are frequently affected by diseases in domestic cats

Alzheimer’s disease (AD) is a progressive neurodegenerative disease resulting in alterations in memory, language, executive function and emotional behaviour. Although it can be characterised by symptoms, by the time they arise significant pathological alterations have already emerged in the central nervous system, namely increased amyloid plaques, neurofibrillary tangles and neuronal loss. Despite known pathological hallmarks the exact aetiology of AD is poorly understood and no current treatments are available. However, there is growing interest in the role of neuroinflammation in AD, with increases observed in the early stages of disease and with disease progression. Moreover, it has been suggested that peripheral inflammation can influence neuroinflammation and worsen neurodegeneration. Using Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRS) we can non-invasively measure biomarkers of neuroinflammation and degeneration allowing multi-modal investigation of its role in normal aging and AD. Considering this the objectives of this study were to (i) Use PET and MRS to investigate neuroinflammatory and metabolite alterations in transgenic (TG) models of AD and their wildtype (WT) animals. (ii) Assess rates of cognitive decline in these models using memory based tests. (iii) Investigate relatively new TgF344AD rat as an AD model by characterising younger time-points than previously reported. (iv) Investigate the contribution of peripheral inflammation on AD progression. PET and MRS imaging was carried out longitudinally in the APPswe×PS1de9 mouse. Neuroinflammation was confirmed ex vivo and cognitive ability was assessed by behavioural tests. Results revealed significantly increase hippocampal and thalamic neuoinflammation in old TG mice as assessed by [18F]DPA-714 PET and supported by immunohistochemistry. Reduced neuronal marker N-acetlyaspartate was seen with age and was exacerbated in the TG mice. Accelerated cognitive decline was also seen in TG mice. PET and MRS imaging was carried out at 6 and 12 months in the TgF344AD model, which expresses amyloid and tau pathology as well as neuronal loss. No cognitive decline was observed in TG rats; however increased anxiety behaviour was seen. Increased [18F]DPA-714 PET was observed as an effect of gene in the thalamus at 6 months and the hypothalamus at 12 months. Increases in glutamate were seen with age in the TG rats but not the WTs. Increased inflammation and metabolite alterations were seen with aging. The effect of peripheral urinary tract infection (UTI) on cognition and imaging out was assessed. Imaging was carried out prior to and after re-current UTI. Infection induced cognitive decline in infected TG but not WT rats. Infection had an increasing effect on hypothalamic neuroinflammation in WT rats but a decreasing effect on TG rats, which masked the original gene differences. This thesis is set out in the alternative format with each experimental study represented as a chapter. Results in this thesis implicate neuroinflammation in AD development and progression. In addition, we report systemic infection-CNS interactions accelerating cognitive decline in AD and highlight the importance of understanding the effects of comorbidities in disease.

Esta dissertação trata do projeto e avaliação de um canal de medição de bioimpedâncias multifrequencial cujo objetivo é a medida em módulo e fase de impedâncias até 1 k com desempenho reportado nas freqüências 100 kHz, 300 kHz e 1 MHz. Um modelo teórico foi desenvolvido para cada etapa do canal de medição incluindo as não idealidades dos componentes utilizados na implementação prática. A análise da sensibilidade à variação de parâmetros e da propagação de incertezas nas etapas do sistema foi realizada juntamente com a avaliação experimental da exatidão e precisão do protótipo desenvolvido. O circuito proposto apresenta incerteza experimental 0,008% nas medidas de amplitude e 0,05% nas medidas de fase. / This dissertation deals with the project and evaluation of a multifrequency bioimpedance measurement channel whose objective is to obtain the measure in module and phase of load impedances up to 1 k with performance reported in 100 kHz, 300 kHz and 1 MHz. A theoretical model was developed for each stage of the measurement channel having included non-idealities of the components used in the practical implementation. The sensitivity analysis with respect to parameter variation and uncertainty analysis in the stages of the system was carried through together with the experimental evaluation of the accuracy and precision of the developed prototype. The considered circuit presents experimental uncertainty of 0.008% in the measures of amplitude and 0.05% in the measures of phase.

Cardiovascular disease is one of the leading causes of the mortality in the western world. Many imaging modalities have been used to diagnose cardiovascular diseases. However, each has different forms of noise and artifacts that make the medical image analysis field important and challenging. This thesis is concerned with developing fully automatic segmentation methods for cross-sectional coronary arterial imaging in particular, intra-vascular ultrasound and optical coherence tomography, by incorporating prior and tracking information without any user intervention, to effectively overcome various image artifacts and occlusions. Combinatorial optimisation methods are proposed to solve the segmentation problem in polynomial time. A node-weighted directed graph is constructed so that the vessel border delineation is considered as computing a minimum closed set. A set of complementary edge and texture features is extracted. Single and double interface segmentation methods are introduced. Novel optimisation of the boundary energy function is proposed based on a supervised classification method. Shape prior model is incorporated into the segmentation framework based on global and local information through the energy function design and graph construction. A combination of cross-sectional segmentation and longitudinal tracking is proposed using the Kalman filter and the hidden Markov model. The border is parameterised using the radial basis functions. The Kalman filter is used to adapt the inter-frame constraints between every two consecutive frames to obtain coherent temporal segmentation. An HMM-based border tracking method is also proposed in which the emission probability is derived from both the classification-based cost function and the shape prior model. The optimal sequence of the hidden states is computed using the Viterbi algorithm. Both qualitative and quantitative results on thousands of images show superior performance of the proposed methods compared to a number of state-of-the-art segmentation methods.

abstract: For decades, microelectronics manufacturing has been concerned with failures related to electromigration phenomena in conductors experiencing high current densities. The influence of interconnect microstructure on device failures related to electromigration in BGA and flip chip solder interconnects has become a significant interest with reduced individual solder interconnect volumes. A survey indicates that x-ray computed micro-tomography (µXCT) is an emerging, novel means for characterizing the microstructures' role in governing electromigration failures. This work details the design and construction of a lab-scale µXCT system to characterize electromigration in the Sn-0.7Cu lead-free solder system by leveraging in situ imaging. In order to enhance the attenuation contrast observed in multi-phase material systems, a modeling approach has been developed to predict settings for the controllable imaging parameters which yield relatively high detection rates over the range of x-ray energies for which maximum attenuation contrast is expected in the polychromatic x-ray imaging system. In order to develop this predictive tool, a model has been constructed for the Bremsstrahlung spectrum of an x-ray tube, and calculations for the detector's efficiency over the relevant range of x-ray energies have been made, and the product of emitted and detected spectra has been used to calculate the effective x-ray imaging spectrum. An approach has also been established for filtering `zinger' noise in x-ray radiographs, which has proven problematic at high x-ray energies used for solder imaging. The performance of this filter has been compared with a known existing method and the results indicate a significant increase in the accuracy of zinger filtered radiographs. The obtained results indicate the conception of a powerful means for the study of failure causing processes in solder systems used as interconnects in microelectronic packaging devices. These results include the volumetric quantification of parameters which are indicative of both electromigration tolerance of solders and the dominant mechanisms for atomic migration in response to current stressing. This work is aimed to further the community's understanding of failure-causing electromigration processes in industrially relevant material systems for microelectronic interconnect applications and to advance the capability of available characterization techniques for their interrogation. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2015

The metal strung harp indigenous to Ireland and Scotland from the Medieval period to the end of the 18th century was widely admired throughout its time period, and is now an important part of the cultural and musical heritage of both of these countries. This type of harp, known as the 'Irish harp', cláirseach, or clàrsach, currently has 18 known surviving instruments, including two sets of fragments. All of these harps are now too fragile to be played, therefore musicians and audiences wishing to explore the performance practice and repertory associated with them must rely on faithful replicas. The extensive knowledge and understanding of the construction of the surviving harps that is crucial to building these replica instruments is currently very limited, however. Although harps of this type enjoyed a long period of use dating back to the Medieval period, most surviving instruments post-date the beginning of the 17th century. Two harps belonging to the National Museum of Scotland, the 'Queen Mary' and 'Lamont', generally dated to circa the 15th century, are understood to be two of the oldest extant examples, making a study of their construction of particular interest. This dissertation presents the results of a comprehensive study of the construction of these two harps. A methodology was developed to address the issue of their uniqueness and fragility by combining the techniques used for non- and minimally destructive analysis of archeological artefacts with non-invasive medical diagnostic imaging. This study has utilized CT-scanning to provide three-dimensional radiography of each harp; XRF and SEM-EDX analysis to identify woods, metals, and pigments; photography and microscopy to record the decorative work, visible damage, repairs, and modifications; and a visual examination to assess the current state of each harp and to identify areas of interest for further analysis. The CT scanning was conducted at the Clinical Research Imaging Centre of Queen's Medical Research Institute, and the remainder of the analysis was conducted at the National Museums Scotland Collections Centre. Staff at both centres kindly facilitated the acquisition of the data for this study. Part I of this dissertation discusses the stringing of the instruments, presenting materials analysis of wire fragments, analysis of the effect of damage to the frames on the length and number of strings, and proposed reconstructions of the 'as-built' string lengths. Possible solutions for the pitch and gamut of each harp are also discussed. The construction of the harps is discussed where it is relevant to understanding the stringing. Part II presents a general discussion of the construction of each harp, including materials, decorative work, modifications, and signs of wear. This section also discusses evidence that may help establish dates of construction and timelines of modifications. Diagrams showing the dimensions of each harp are also presented. The implications of the results of this study for current understanding of these harps are discussed in detail and the methodology employed is discussed in terms of its applicability to future research of other surviving instruments.

Constraining the behaviour of small fractions of partial melt in a solid silicate matrix has been the focus of numerous experimental petrology studies over several decades, and is an important factor in constraining upper mantle rheology, melt extraction at mid-ocean ridges and mechanisms of core formation in the early solar system. Deformation of partially molten rock has been observed to change melt geometry, and may enhance permeability and interconnectivity of melt otherwise trapped in a solid silicate matrix, although it is uncertain how applicable results of high strain-rate laboratory experiments are to the real Earth. The addition of deformation precludes attainment of textural equilibrium, complicating textural analysis, which has previously relied on extrapolation of 3D textures from quenched and polished 2D sections for hydrostatically annealed samples. X-ray computed tomography gives the potential to visualise sample textures directly in three dimensions, and is becoming popular as a complementary technique for textural analysis in petrologic studies. The aim of this project has been to develop techniques to improve visualisation of small fractions of partial melt within a solid silicate matrix using X-ray CT, to examine textures of various partially molten systems at high PT in hydrostatic, and dynamically deforming systems. Experiments carried out in the FeS-melt, solid olivine system have examined the potential for deformation-enhanced percolation of core forming melts before the onset of silicate melting. Access to the newly designed rotational Paris-Edinburgh Cell (roPEC/rotoPEC) equipment has allowed us to carry out controlled, torsional deformation experiments under PT conditions applicable to planetary interiors. Experiments conducted at lower strain-rates over longer duration than in previously published studies show that deformation enhances connectivity at low melt fractions, at strain-rates down to 10-6s-1. This is in contrast to earlier work suggesting melt textures are unaffected at strain-rates below 10-5s-1. Quenched melt networks have been fully characterised in 3D using multi-scale CT, with voxel sizes down to 70nm for small sample sub-volumes. Results suggest segregation of metallic melt below the silicate solidus could be an efficient process, and should be taken into account in geochemical models of planetary evolution. Experiments on basaltic melt in a solid silicate matrix were conducted in application to upper mantle melting. A heavy element, hafnium, was added to the basaltic glass starting composition to enhance contrast between the basalt and olivine phases during CT scans. In-house micro-CT equipment was used to visualise post-quench run products of hydrostatic and deformation experiments. The doping technique was successful for long-duration, high temperature hydrostatic experiments. Some issues with undissolved / re-precipitated HfO¬2 crystals complicated tomographic imaging of partial melt textures in a number of experiments, particularly those carried out on the rotoPEC equipment, limiting comparison between samples. The doping technique requires further adjustment, but is shown to be a viable way to improve visibility of basaltic melt without significantly affecting melt texture. The X-ray transparent design and fully rotating top and bottom anvils of the rotoPEC allow X-ray tomography to be carried out in-situ while experiments are in progress, enabling collection of 4D datasets. During this project, the rotoPEC equipment was incorporated into two different synchrotron beamlines, to carry out time-resolved studies of textural development within samples of varying composition. The migration of gold melt along fractures with a BN matrix was imaged using 2D radiography, in combination with repeated 3D tomography to fully characterise the 3D fracture geometry. This allowed melt migration velocity to be estimated directly from in-situ observations. These techniques could be developed further to constrain melt migration processes quantitatively for a number of geological systems in the near future.

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 adaptation. / Fluorescence 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.

Orientador: Elenice Deffune / Banca: José Morceli / Banca: João Paulo Kawaoca Mitsushita / Resumo: A Infiltração gordurosa hepática (IGH) ou esteatose hepática (EH) não é condição benigna na medida em que muitos pacientes, além de acúmulo de gordura nos hepatócitos, desenvolvem alterações necro-inflamatórias do fígado e apresentam evidências de injúria hepatocelular chamada de esteatohepatite, cerca de 20% destes pacientes evoluem para cirrose 1. A IGH é identificada por biópsias e estudos de imagem. Quando a infiltração gordurosa tem distribuição focal ou o fígado esteatótico tem áreas poupadas podem simular pseudotumores. A análise da tomografia computadorizada (TC) tem a característica de baixa atenuação da gordura em relação ao parênquima hepático normal. A quimioterapia pode ser causa de IGH e neste trabalho estudamos a IGH em pacientes em tratamento com quimoterápicos para linfoma. Os linfomas são doenças malignas originárias de proliferação sem controle de células linfáticas, a incidência anual de Linfoma é de 12 a 19 casos por 100.000 pessoas e o tratamento se baseia predominantemente em esquemas de quimioterapia. Não existe até o momento trabalho que avalie aspectos da IGH e que os relacione aos esquemas de quimioterapia para linfoma. Este estudo tem por objetivo avaliar e caracterizar a IGH, através da TC de abdome sem contraste, associada ao uso de esquemas quimioterápicos para !infoma. Casuística e Métodos: 115 prontuários de pacientes com diagnóstico de linfoma e suas respectivas tomografias de abdome foram revisados. As tomografias analisadas foram aquelas realizadas antes, durante e após o início da quimioterapia, acompanhando a progressão da esteatose hepática no decorrer dos ciclos de quimioterapia. Os tipos de esquema de quimioterapia, número de ciclos e esquemas, exames laboratoriais foram caracterizados e discutidos. Resultados: A incidência de IGH entre os pacientes estudados foi 27,8%... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Hepatic fat infiltration (HFI) or hepatic steatosis (HS) is not a benign condition as many patients, through fat accumulation in hepatocytes, develop necro-inflammatory alterations of the liver and present evidence of hepatocellular injury called steatohepatitis, of which about 20% of patients progress to cirrhosis 1. HFI is identified by biopsies and imaging. In diffuse fat infiltration lesions can be focally distributed or in undamaged areas of the steatotic liver, which can simulate pseudo-tumours. With Computerized Tomography fat appears with low attenuation characteristic in relation to normal hepatic parenchyma. Chemotherapy can cause HFI. In this work we studied HFI in patients on chemotherapy for Iymphoma. Lymphomas are malignant diseases derived from uncontrolled proliferation of Iymphatic cells. The annual incidence of Iymphoma is between 12 and 19 cases per 100,000, and treatment is predominantly based on chemotherapy regimes. At this time there are no studies evaluating the aspects of HFI which are related to chemotherapy regimes for Iymphoma. The objective of this study was to evaluate and characterize HFI using abdominal CT without contrast, associated to the use of chemotherapy in Iymphoma. Patients & Methods: medical records from 115 patients diagnosed with Iymphoma and their respective abdominal tomographies were reviewed. Tomographies were from before, during and after the start of chemotherapy, following the progress of hepatic steatosis through the chemotherapy cycles. Chemotherapy regime type, number of cycles and types, and laboratory examinations were characterized and discussed. Results: The incidence of HFI in this population was 27.8%. The relationship between increased cycles and increased HFI was significant; so was the relationship between number of regimes and HFI incidence... (Complete abstract, click eletronic address below) / Mestre

A instabilidade patelar é uma patologia comum dentro da especialidade da cirurgia do joelho. O principal fator estabilizador dessa articulação é o ligamento patelofemoral medial, sendo esta a principal estrutura a ser reconstruída no tratamento cirúrgico da instabilidade patelar. Apesar de sua reconstrução apresentar excelentes resultados clínicos, não se sabe ao certo o real efeito in vivo desse procedimento no movimento da patela ao redor do fêmur. A avaliação da articulação patelofemoral tradicionalmente é feita através de exames de imagem estáticos. Com a evolução dos aparelhos de tomografia computadorizada, se tornou possível realizar esse exame durante movimento ativo, técnica ainda pouco utilizada para estudo de articulações como o joelho. O objetivo deste estudo foi padronizar o uso da tomografia de 320 fileiras de detectores para estudo dinâmico da articulação patelofemoral em pacientes com instabilidade patelar recidivante pré e pós-reconstrução do ligamento patelofemoral medial, analisando o efeito da cirurgia no trajeto da patela ao longo do arco de movimento. Foram selecionados 10 pacientes com instabilidade patelar e indicação de reconstrução do ligamento patelofemoral medial isolada, que foram submetidos à tomografia antes e após um mínimo de 6 meses da cirurgia. Os parâmetros anatômicos avaliados foram os ângulos de inclinação da patela e distância da patela ao eixo da tróclea através de um programa de computador desenvolvido especificamente para esse fim. Foram aplicados os escores clínicos de Kujala e Tegner e calculada a radiação dos exames. O protocolo escolhido para aquisição de imagens na tomografia foi: potencial do tubo de 80 kV, carga transportável de 50 mA, espessura de corte de 0,5 mm e tempo de aquisição de 10 segundos, o que gerou um DLP (dose length product) de 254 mGycm e uma dose efetiva estimada de radiação de 0,2032 mSv. O paciente realizava uma extensão ativa do joelho contra a gravidade. Os resultados não mostraram mudança do trajeto da patela após a reconstrução do ligamento patelofemoral medial, apesar de não ter havido nenhuma recidiva da instabilidade e os escores clínicos apresentarem melhora média de 22,33 pontos no Kujala (p=0,011) e de 2 níveis no Tegner (p=0,017) / Patellar instability is a common pathology in the practice of knee surgeons. The most important stabilizing structure in the patellofemoral joint is the medial patellofemoral ligament. This ligament is the main structure to be reconstructed during surgery for patellofemoral instability. Although clinical results for this procedure are excellent, the real in vivo effect of medial patellofemoral ligament reconstruction on patellar tracking is unknown. The study of this joint is usually made with static imaging. With the recent evolution of tomographers, it is now possible to analyze anatomical structures moving during active range of motion. This technique (dynamic computerized tomography) has not been routinely used to study joints as the knee. This study had the purpose of standardizing the use of 320-detector row computerized tomography for the patellofemoral joint, analyzing patients before and after surgical reconstruction of medial patellofemoral ligament. We selected 10 patients with patellofemoral instability referred to isolated medial patellofemoral ligament reconstruction surgery, and submitted them to a dynamic computerized tomography before and at a minimum of 6 months after surgery. Patellar tilt angles and shift distance were analyzed using a computer software specifically designed for this purpose. Kujala and Tegner scores were applied and the radiation of the exams was recorded. The protocol for imaging acquisition was: tube potential of 80 kV, 50 mA, slice thickness of 0.5 mm and 10 seconds of acquisition duration. This produced a DLP (dose length product) of 254 mGycm and a radiation effective estimated dose of 0.2032 mSv. There were no changes in patellar tracking after medial patellofemoral ligament reconstruction. There was no instability relapse. Clinical scores showed an average improvement of 22.33 points for Kujala (p=0.011) and of 2 levels for Tegner (p=0.017)