A introdução dos endoscópios na otorrinolaringologia determinou um grande avanço tecnológico, permitindo a sistematização da cirurgia endoscópica nasossinusal funcional. A possibilidade de trabalhar nos limites das cavidades nasossinusais com boa iluminação e visibilidade permitiu a expansão dessa cirurgia para abordar lesões da base do crânio e no interior da cavidade craniana, ampliando consideravelmente as suas indicações e a gravidade das suas complicações. Dentre estas complicações as lesões vasculares e ou de nervos cranianos estão entre as principais causas de morbidade. A artéria frontobasilar medial (AFM) é o primeiro ramo cortical do segmento pós-comunicante da artéria cerebral anterior e possui percurso próximo a base anterior do crânio. Havendo penetração intracraniana através da base anterior do crânio, durante uma cirurgia endoscópica endonasal, a AFM pode ser lesionada causando graves complicações. O objetivo deste estudo foi analisar as relações da AFM com a base anterior do crânio e reparos anatômicos utilizados em cirurgia endonasal, através de imagens obtidas por angiotomografia de crânio. E também identificar os locais de maior proximidade da AFM com a base anterior do crânio, sugerindo áreas de maior risco de lesão em cirurgia endonasal. Foram analisados 52 exames de angiotomografia de crânio, realizados no período de 2013 a 2015. O software OsiriXÒ foi utilizado para fazer as medições entre a AFM e os pontos de referência nos planos sagital e coronal, na ordem cronológica em que os exames foram coletados. A AFM descreveu um trajeto descendente, próximo a linha média (distancia média de 1,5 mm), se aproximando do plano esfenoidal (distancia média de 1,8 mm) e depois um trajeto ascendente à medida que se dirige para porção anterior do crânio, com distância média de 4,4mm na região da parede anterior do seio esfenoidal e de 12mm na região onde se encontra a artéria etmoidal anterior. Considerando o ângulo de trabalho na cirurgia endonasal e a os locais de maior proximidade da AFM com a base anterior do crânio, as regiões do etmoide posterior e plano esfenoidal foram as áreas de maior risco de sua lesão Study of the relations between medial orbitofrontal artery and anterior skull base performed by computed tomography angiography / The introduction of endoscopes in otolaryngology determined a great technological advance, allowing the systematization of the endoscopic endonasal sinus surgery. The possibility of working at the nasal cavity boundaries with good illumination and visibility allowed the expansion of this surgery to address lesions of the skull base and inside the cranial cavity, considerably broadening its indications and the severity of its complications. Among these complications, vascular lesions and cranial nerves are among the main causes of morbidity. The medial orbitofrontal artery (MOFA) the first cortical branch of the post-communicating segment of the anterior cerebral artery and has a path near the anterior skull base. If there is an intracranial penetration through the anterior skull base, during endonasal surgery, the MOFA can be injured causing serious complications. The objective of this study was to analyze the MOFA relations with the anterior skull base and anatomical repairs used in endonasal surgery, through images obtained by computed tomography angiography. And also identify the sites of greater proximity of the MOFA with the anterior skull base, suggesting areas of greater risk of injury in endonasal surgery. It was studied 52 examinations of skull computed tomography angiography performed between 2013 and 2015. The OsiriXÒ software was used to make the measurements between the MOFA and the reference points in the sagittal and coronal planes, in the chronological order in which the exams were collected. The MOFA described a descending path, close to the midline (average distance of 1.5 mm), approaching the sphenoid plane (average distance of 1.8 mm) and then an ascending path as it is directed towards the anterior portion of the skull, with an average distance of 4.4 mm in the region of the anterior wall of the sphenoid sinus and 12 mm in the region where the anterior ethmoid artery is located. Considering the angle of work in endonasal surgery and the places of greater proximity of the MOFA with the anterior skull base, the regions of the posterior ethmoid and sphenoid plane were the areas of greatest risk of its lesion

Este trabalho faz parte de um projeto maior, o Annotation and Image Markup Project, que tem o objetivo de criar uma base de conhecimento médico sobre imagens radiológicas para identificação, acompanhamento e reasoning acerca de lesões tumorais em pesquisas sobre câncer e consultórios médicos. Esse projeto está sendo desenvolvido em conjunto com o Radiological Sciences Laboratory da Stanford University. O problema específico, que será abordado nesse trabalho, é que a maior parte das informações semânticas sobre imagens radiológicas não são capturados e relacionados às mesmas usando termos de ontologias biomédicas e padrões, como o RadLex e DICOM, o que impossibilita a sua avaliação automática por computadores, busca em arquivos médicos em hospitais, etc. Para tratar isso, os radiologistas precisam de uma solução computacional fácil, intuitiva e acessível para adicionar essas informações. Nesse trabalho foi desenvolvida uma solução Web para inclusão dessas anotações, o sistema ePAD. O aplicativo permite a recuperação de imagens médicas, como as imagens disponíveis em sistemas de informação hospitalares (PACS), o delineamento dos contornos de lesões tumorais, a associação de termos ontológicos a esses contornos e o armazenamento desses termos em uma base de conhecimento. Os principais desafios desse trabalho envolveram a aplicação de interfaces intuitivas baseadas em Rich Internet Applications e sua operação a partir de um navegador Web padrão. O primeiro protótipo funcional do ePAD atingiu seus objetivos ao demonstrar sua viabilidade técnica, sendo capaz de executar o mesmo trabalho básico de anotação de aplicações Desktop, como o OsiriX-iPad, sem o mesmo overhead. Também mostrou a sua utilidade a comunidade médica o que gerou o interesse de usuários potenciais / This work is a part of a larger project, the Annotation and Markup Project, which aims to create a medical knowledge base about radiological images to identify, monitor and reason about tumors in cancer research and medical practices. This project is being developed in conjunction with the Laboratory of Image Informatics at Stanford University. The specific problem that will be addressed in this work is that most of the semantic information about radiological images are not captured and related to them using terms of biomedical ontologies and standards, such as RadLex or DICOM, what makes it impossible to automatic evaluate them by computers, to search for them in hospital databases using semantic criteria, etc. To address this issue, radiologists need an easy, intuitive and affordable computational solution to add this semantic information. In this work, a web solution for adding the information was developed, the ePAD system. It allows the retrieval of medical images, such as images available in hospital information systems (PACS), the creation of contours around tumor lesions, the association of ontological terms to these contours, and the storage of this terms in a knowledge base. The main challenges of this work involved the creation of intuitive interfaces using Rich Internet Applications technology and the operation from a standard Web Browser. The first functional prototype of ePAD reached its goal of proving its technical feasibility. It was able to do the same basic annotation job of desktop applications, such as OsiriX-iPad, without the same overhead. It also showed to the medical community that it was a useful tool and that generated interest of potential early users

Este projeto teve como finalidade fornecer informações sobre o contingente brasileiro de garanhões afetados pela osteocondrose dissecante (OCD), particularmente no estado de São Paulo. A OCD é uma doença ortopédica do desenvolvimento que acomete os humanos e os animais. É o distúrbio de desenvolvimento esquelético mais importante nos potros em crescimento. É uma falha no processo de ossificação endocondral, que compromete as cartilagens articular e de crescimento, principalmente a articulação tíbio-társica. É uma afecção importante pela incapacitação de atletas e é questão de caráter mundial para o bem-estar animal e para a eqüinocultura, implicando o seu tratamento e estratégias de controle. Há várias modalidades diagnósticas utilizadas na triagem da população acometida pela OCD, que se distinguem de acordo com a acurácia de cada uma. Entretanto, a radiologia, com imagens digitais, ainda se mantém como a ferramenta mais utilizada no campo. Os garanhões foram escolhidos considerando-se a idade, a sanidade, a maturidade, a docilidade e estavam obrigatoriamente registrados no stud-book da ABCCH. Os eqüinos foram submetidos a duas incidências radiográficas bilaterais das articulações tíbio-társicas. Os arquivos foram armazenados em sistema digital e os achados classificaram os animais em positivos e negativos para OCD. Os resultados demonstraram uma ocorrência de 7,7% (2/26) de OCD na população brasileira de garanhões, produtos de inseminação artificial com sêmen importado com a garantia OCD-Free de centrais européias de reprodução. Esta porcentagem se apresentou menor do que as relatadas por pesquisadores de outros países, indicando que o plantel brasileiro de garanhões se apresenta controlado para a OCD e abaixo da expectativa. A baixa ocorrência de OCD nos eqüinos no Brasil, em relação aos outros países, pode ser atribuída ao método de seleção dos reprodutores e também a fatores climáticos. / This project provides information about osteochondrosis dissecans (OCD) affection in Brazilian Warmblood stallions, particularly in the state of Sao Paulo. Osteochondrosis dissecans is a developmental orthopaedic disease, which can involve both humans and animals. It is the most important skeletal disorder in growing foals. It is a failure of the endochondral ossification, which affects both articular and growth-plate cartilages. The tibiotarsal joint is the primary region involved. It is a remarkably disabling condition for competing animals and a serious worldwide issue for animal welfare and the horse industry and involves various treatments and control strategies. There are several modalities of diagnosis used to investigate the OCD, which differ from each other according to their rate of accuracy. However, radiology utilizing digitized images remains the most appropriate tool in the field. The stallions were chosen by the criteria of age, official registration in the ABCCH (Brazilian Sport Horses Breeders\' Association), soundness, maturity and behaviour. The horses were submitted bilaterally to two radiographic views of their hocks. The images were stored in digital files for further individual classification into positive or negative diagnosis. The results yielded an incidence of 7.7% (2/26) of OCD within the Brazilian population of stallions, all of whom were artificial insemination drives offspring, sired from imported European stallions using \"OCD-free\" semen. These results show a lower incidence of OCD than obtained by other countries\' researchers, indicating that the Brazilian stallions are under control for OCD and below the expected mean. The low incidence of OCD in Brazil, in comparison with other countries may be due to the methods of selection established for choosing quality of the semen or to climate differences.

A camada semi-redutora (CSR), definida como a espessura de um material absorvedor que colocado sob um feixe de raios-X reduz sua intensidade à metade, é um parâmetro que deve ser avaliado periodicamente nos programas de garantia de qualidade em radiologia médica, pois fornece informações a respeito do desempenho do feixe radiográfico produzido pelo aparelho. Todavia, sua medida é normalmente feita na região central do campo de exposição e não considera a variação da qualidade relativa do feixe ao longo de toda a sua extensão, causada essencialmente pelo efeito heel. Em vista disso, o presente trabalho propõe um algoritmo de simulação computacional para determinar a CSR de aparelhos radiográficos em qualquer posição no campo através de uma única medida na região central, para permitir uma avaliação mais completa da variação da qualidade do feixe em função do posicionamento do objeto no plano imagem. Além disso, a partir dos resultados obtidos, também é proposto um procedimento computacional capaz de determinar filtros de características específicas para compensar essas variações na qualidade da imagem causadas pelo efeito heel e também por variações na espessura do objeto radiografado. Os resultados obtidos com os programas de simulação desenvolvidos mostraram-se coerentes com os obtidos em testes práticos realizados com aparelhos radiográficos hospitalares, comprovando a validade dos algoritmos propostos. / The half-value layer (HVL) is defined as the thickness of an absorbing material which placed under an X-Ray beam reduces its intensity to half. It is a parameter that should be periodically evaluated in medical radiology quality control programs because it gives information related to the radiographic system beam performance. However, its measurement is done normally at the center of the radiation field, not taking into account the beam relative quality variation along the field, caused essentially by the heel effect. Bearing that in mind, the present work proposes a computer simulation algorithm to determine the radiographic systems HVL at any location on the field based on a single measurement at the central area, to allow a more complete evaluation of the beam quality variation due to the object location on the image plane. Furthermore, from these results, another computer simulation procedure is proposed to determine particular filter characteristics to compensate these image quality variations caused by the heel effect and also by the X-rayed object thickness variation. The results obtained from the simulation programs are consistent with the experimental results performed in medical radiographic systems, confirming therefore the validity of the proposed algorithms.

A introdução dos endoscópios na otorrinolaringologia determinou um grande avanço tecnológico, permitindo a sistematização da cirurgia endoscópica nasossinusal funcional. A possibilidade de trabalhar nos limites das cavidades nasossinusais com boa iluminação e visibilidade permitiu a expansão dessa cirurgia para abordar lesões da base do crânio e no interior da cavidade craniana, ampliando consideravelmente as suas indicações e a gravidade das suas complicações. Dentre estas complicações as lesões vasculares e ou de nervos cranianos estão entre as principais causas de morbidade. A artéria frontobasilar medial (AFM) é o primeiro ramo cortical do segmento pós-comunicante da artéria cerebral anterior e possui percurso próximo a base anterior do crânio. Havendo penetração intracraniana através da base anterior do crânio, durante uma cirurgia endoscópica endonasal, a AFM pode ser lesionada causando graves complicações. O objetivo deste estudo foi analisar as relações da AFM com a base anterior do crânio e reparos anatômicos utilizados em cirurgia endonasal, através de imagens obtidas por angiotomografia de crânio. E também identificar os locais de maior proximidade da AFM com a base anterior do crânio, sugerindo áreas de maior risco de lesão em cirurgia endonasal. Foram analisados 52 exames de angiotomografia de crânio, realizados no período de 2013 a 2015. O software OsiriXÒ foi utilizado para fazer as medições entre a AFM e os pontos de referência nos planos sagital e coronal, na ordem cronológica em que os exames foram coletados. A AFM descreveu um trajeto descendente, próximo a linha média (distancia média de 1,5 mm), se aproximando do plano esfenoidal (distancia média de 1,8 mm) e depois um trajeto ascendente à medida que se dirige para porção anterior do crânio, com distância média de 4,4mm na região da parede anterior do seio esfenoidal e de 12mm na região onde se encontra a artéria etmoidal anterior. Considerando o ângulo de trabalho na cirurgia endonasal e a os locais de maior proximidade da AFM com a base anterior do crânio, as regiões do etmoide posterior e plano esfenoidal foram as áreas de maior risco de sua lesão Study of the relations between medial orbitofrontal artery and anterior skull base performed by computed tomography angiography / The introduction of endoscopes in otolaryngology determined a great technological advance, allowing the systematization of the endoscopic endonasal sinus surgery. The possibility of working at the nasal cavity boundaries with good illumination and visibility allowed the expansion of this surgery to address lesions of the skull base and inside the cranial cavity, considerably broadening its indications and the severity of its complications. Among these complications, vascular lesions and cranial nerves are among the main causes of morbidity. The medial orbitofrontal artery (MOFA) the first cortical branch of the post-communicating segment of the anterior cerebral artery and has a path near the anterior skull base. If there is an intracranial penetration through the anterior skull base, during endonasal surgery, the MOFA can be injured causing serious complications. The objective of this study was to analyze the MOFA relations with the anterior skull base and anatomical repairs used in endonasal surgery, through images obtained by computed tomography angiography. And also identify the sites of greater proximity of the MOFA with the anterior skull base, suggesting areas of greater risk of injury in endonasal surgery. It was studied 52 examinations of skull computed tomography angiography performed between 2013 and 2015. The OsiriXÒ software was used to make the measurements between the MOFA and the reference points in the sagittal and coronal planes, in the chronological order in which the exams were collected. The MOFA described a descending path, close to the midline (average distance of 1.5 mm), approaching the sphenoid plane (average distance of 1.8 mm) and then an ascending path as it is directed towards the anterior portion of the skull, with an average distance of 4.4 mm in the region of the anterior wall of the sphenoid sinus and 12 mm in the region where the anterior ethmoid artery is located. Considering the angle of work in endonasal surgery and the places of greater proximity of the MOFA with the anterior skull base, the regions of the posterior ethmoid and sphenoid plane were the areas of greatest risk of its lesion

Esta pesquisa caracteriza-se como qualitativa e descritiva, tendo por objetivo mapear os processos de geração e uso de informações clínicas no contexto da Radiologia Médica, utilizando como referência o Ciclo Informacional estudado na Ciência da Informação, visando a identificar metadados que possam ser empregados em arquivos didáticos para uso em práticas de ensino em Radiologia. A metodologia é dividida em quatro etapas: 1) estudo do ciclo informacional, com o intuito de conhecer propostas de autores que sistematizam os processos de geração e uso da informação; 2) descrição do fluxo de trabalho de um departamento de Radiologia Médica - IHE -, para identificar os diferentes atores nesse ambiente; 3) análise dos processos do ciclo informacional no fluxo de trabalho de um departamento de Radiologia Médica, para entender o processo de geração e uso de informações na área; e 4) análise comparativa entre os metadados indicados para o fluxo de trabalho de um departamento de Radiologia Médica - DICOM - e os metadados utilizados nas bases de imagens médicas MyPACs e Auntminnie, a fim de levantar um conjunto de informações da prática clínica para uso em arquivos didáticos. Ao estudar o fluxo de trabalho de um departamento de Radiologia foram mapeadas as informações geradas e utilizadas em cada etapa, resultando na identificação de um conjunto de metadados advindos da prática clínica, que podem ser utilizados na criação de arquivos didáticos. Neste trabalho, conclui-se que estudar os processos de geração e uso de informações clínicas, em conjunto com outros temas, pode ajudar a pensar em metodologias para organização da informação, com a finalidade de viabilizar a recuperação de informação entre aplicações que possam ser utilizadas em contextos diversos no ambiente da Radiologia Médica. / This qualitative and descriptive research aimed to map the processes related to generation and use of clinical information in Medical Radiology. In order to identify metadata for creating Radiology teaching files, the Information Cycle - adopted by Information Science - has been used such as a theoretical reference. The methodological approach was divided into four steps: 1) aiming to know approaches proposed by authors who systematize the processes related to information\'s generation and use, the information cycle was investigated; 2) by systematizing the workflow found in a Radiology Department (by using IHE\'s documents), regular users present in this environment were identified; 3) based on Medical Radiology\'s workflow and aiming to understand the information\'s generation and use processes, the steps part of the information cycle were studied; and 4) comparative analysis using metadata part of Radiology Department\'s workflow (based on DICOM standard documentation) and metadata used in the MyPACs and Auntminnie medical image databases, such analysis was done in order to select a set of information from clinical practice which may be used in teaching files\' creation. When the Radiology\'s workflow was studied, the information generated and used in each step was identified. As a result, groups of metadata from the clinical practice were identified and such metadata may be used aiming to create teaching file. In this work, we have concluded that by investigating processes related to clinical information generation and use, combined with other themes, may help to think about information organization\'s methodologies. This offers means to retrieve information from various clinical systems and the retrieved information can be used in different Radiology contexts.

Radiologic technologists who transition into the role of clinical instructor are usually expert practitioners but may lack knowledge of best practices regarding student instruction and evaluation. The purpose of this phenomenological qualitative study was to investigate how CIs experience the transition from practitioner to educator and what knowledge or education of best practices of instruction and evaluation they bring to the position. This study consisted of interviews with radiography CIs from one associate degree radiography program in the southeastern part of the United States. While some CIs felt prepared to transition into the CI role, none of them had previously had education regarding instruction. They were provided support as they transitioned, but little formal orientation or training. The results of this study should challenge radiography programs to implement or strengthen current orientation programs for new CIs who are critical to student success.

The usage of deep learning algorithms such as Convolutional Neural Networks within the field of medical imaging has grown in popularity over the past few years. In particular, these types of algorithms have been used to detect abnormalities in chest x-rays, one of the most commonly performed type of radiographic examination. To try and improve the workflow of radiologists, this thesis investigated the possibility of using convolutional neural networks to create a lung triage to sort a bulk of chest x-ray images based on a degree of disease, where sick lungs should be prioritized before healthy lungs. The results from using a binary relevance approach to train multiple classifiers for different observations commonly found in chest x-rays shows that several models fail to learn how to classify x-ray images, most likely due to insufficient and/or imbalanced data. Using a binary relevance approach to create a triage is feasible but inflexible due to having to handle multiple models simultaneously. In future work it would therefore be interesting to further investigate other approaches, such as a single binary classification model or a multi-label classification model.

<p>The tumor vasculature is poor and heterogeneous which may result in inadequate oxygenation and changed energy status. In addition the balance between cell proliferation and the rate of cell death is disturbed, which results in tumor growth. </p><p>The aims of this study were 1) to gain more insight into the relation between tumor vascularity, hypoxia, and proliferation in solid tumors, and 2) to study the changes and dynamics of tumor oxygenation in relation to the vascular architecture within individual tumors. For this purpose a double hypoxic marker method was developed, which was subsequently used to 3) determine the turnover rate of hypoxic cells in three different tumor models and 4) to study the effect of cytotoxic drugs on tumor hypoxia and cell death.</p><p>Solid tumor models grown in mice were used. The tumor microenvironment was investigated with exogenous cell markers for hypoxia (pimonidazole and CCI-103F), cell proliferation (BrdUrd) and blood perfusion (Hoechst 33342). The vasculature and the exogenous cell markers were visualized with immunohistochemical techniques. The tumor sections were scanned and quantified with an image analysis systemconsisting of a fluorescence microscope, CCD camera and image analysis software.</p><p>The spatial organization of hypoxia, proliferation, and tumor vasculature was analyzed in several xenograft lines. The study revealed two main hypoxic patterns that seemed to be the consequence of complex relations between vasculature, oxygen delivery, proliferation, and cell loss. The novel double hypoxic cell marker method, with sequential injection of two hypoxic markers, was developed to study dynamic changes of the tumor oxygenation. Based on varying injection intervals between the markers the hypoxic cell half-life was determined in three tumor lines, and ranged from 17 to 49 hours. Intra-tumoral changes in oxygenation status upon oxygen modifying treatments were measured with the double hypoxic marker method. Both decreased levels of tumor hypoxia after carbogen breathing (95%O2 and 5% CO2) and increased levels of tumor hypoxia, as a result of reduced tumor perfusion after hydralazine treatment was detected. Finally the double hypoxic marker assay was used to analyze the effects of the hypoxic cytotoxin tirapazamine in relation to the hypoxic cell population, which caused a reversible decrease of the hypoxic fraction.</p><p>The results presented in this thesis now form the basis for further studies to identify subpopulations of cells that represent specific targets for therapy, and to investigate the effects of different treatment modalities.</p>

<p>The purpose of this work was to improve the diagnosis of intracranial hemorrhage with MRI, using, among others, T2*-w GE sequences. Various sequences were tested in rabbits at two magnetic field strengths. Then, the most effective technique was applied to stroke patients. </p><p>Experimental studies: The MR detectability of small experimental haematomas in the brain and of blood in the cerebrospinal fluid (CSF) spaces of 30 rabbits was evaluated. MRI examinations were performed at determined intervals. The last MR images were compared to formalin fixed brain sections and, in 16 rabbits, also to the histological findings. T2*-weighted GE sequences revealed all the intraparenchymal haematomas at 1.5 T, appearing strongly hypointense. Their signal patterns remained unchanged during the follow-up. Blood in the CSF spaces was best detected at 1.5T with T2*-weighted GE sequences during the first 2 days. FLAIR and SE sequences were rather insensitive.</p><p>Clinical studies: MR examinations were performed at 1.5T, including T1- and T2-w SE, FLAIR and T2*-w GE sequences. In the first clinical study, 66 intraparenchymal hematomas (IPH) of different sizes and ages were examined. T2*-w GE sequence was the most sensitive. On all the sequences, we found a big variety of signal patterns, without a clear relationship to the age of the hematomas. </p><p>In a second clinical study, MR examinations were performed to 83 patients with acute stroke: 43 presented acute IPH and 40 were used as controls. Old microhemorrhages (OMHs) were found in 60% of the patients with IPH, and in 15% of the controls. </p><p>Conclusion: T2*-weighted GE sequences are capable of revealing very small intraparenchymal hemorrhages at any stage, and blood in CSF spaces during at least the first 2 days. The age of IPHs cannot reliably be estimated with MRI. We have found a correlation between the presence of OMHs and acute intraparenchymal hematomas.</p>