A embolização intra-arterial é rotineiramente utilizada na prática clinica como co-adjuvante pré-operatório ou controle de tumores, tratamento de malformações arteriovenosas e outras doenças vasculares. Em vários casos é realizada com uso de partículas de diferentes formas e composições. Um agente embolizante esférico e utilizado com bons resultados é o trisacryl (Embosphere®; BioSphere® Medical). Um novo agente embólico - polivinil acetato esférico cobertas com polivinil álcool (PVAc) foi desenvolvido recentemente no Brasil. Este trabalho tem objetivo de avaliar, após embolização renal, o grau de oclusão vascular, recanalização da luz vascular e a necrose da parede vascular provocados por partículas de PVAc, utilizando como parâmetro partículas de trisacryl. Setenta e nove fêmeas de coelhos do tipo albino New Zealand foram submetidas a cateterização arterial do rim direito; trinta e três animais foram embolizados com trisacryl, trinta e um com PVAc e quinze animais compuseram o grupo de simulação, tendo sido excluídos quatro animais (três trisacryl e um PVAc) devido a óbito precoce. Foram criados cinco subgrupos de seis animais, que foram sacrificados após 48 horas, 5 dias, 10 dias, 30 dias e 90 dias após a embolização. O grupo de simulação seguiu a mesma ordem temporal com três animais em cada grupo. As técnicas de coloração utilizadas foram os métodos de hematoxilina-eosina (HE) e tricrômico de Masson com observação por microscopia óptica. Os resultados mostraram diferença significativa entre o grau de oclusão vascular nos grupos de 5 dias e 10 dias e necrose no grupo de 48 horas em favor do grupo embolizado com PVAc, que apresentou reação tecidual adequada (redução volumétrica e isquemia) e menor grau de recanalização que o trisacryl / Intra-arterial embolization is often utilized in medical practice preoperatively as adjuvant in controlling tumors, treatment of arteriovenous malformations and other vascular diseases. Often times, particles of different forms and compositions are employed. trisacryl (Embosphere®; BioSphere® Medical), a spheric embolic agent, is nowadays used with very satisfactory results. However, a new embolic agent spheric polyvinyl alcohol-covered polivinyl acetate (PVAc)- has been developed in Brazil. This study evaluates the degree of vascular occlusion, vascular recanalization and the necrosis of vascular wall caused by PVAc particles, compared with trisacryl, after renal embolization. Seventy-nine female albine New Zealand rabbits underwent arterial catheterization of the right kidney; Thirty-three animals were embolized with trisacryl, thirty-one with PVAc and fifteen were kept as control group, four animals were excluded (three trisacryl and one PVAc) due to early death. Five subgroups of six animals were created. The animals in the different groups were sacrificed 48 hours, 5 days, 10 days, 30 days and 90 days after embolization. The control group was divided into subgroups of three animals, for the same period of time. Their kidneys were dyed with hematoxylin-eosin (HE) and Masson tricromic and examined using optic microscopy. The results showed a significant difference between the five-day and ten-day groups with regard to the degree of vascular occlusion, and the amount of necrosis in the forty-eight-hour group. Both findings favor the PVAc group, with adequate tissue reaction (ischemia and volumetric reduction) and less recanalization than with trisacryl

Este estudo teve como finalidade principal avaliar a qualidade de vida (QV) dos profissionais de saúde que compõem o serviço de radiodiagnóstico de um hospital da cidade de São Paulo. Além disso, objetivou conhecer o perfil desses profissionais, identificando as variáveis que podem influenciar a QV desses profissionais. Trata-se de um estudo descritivo e exploratório com abordagem quali-quantitativa. Os dados foram coletados usando os questionários: o instrumento abreviado de avaliação de QV - World Health Organization Quality of Life Instrument bref (WHOQOL-bref) da Organização Mundial da Saúde e um questionário sobre as variáveis de interesse: sociodemográficas, condições de trabalho e estilo de vida, ambos questionários auto-aplicáveis. A amostra foi constituída de 118 profissionais nas categorias de: médicos, tecnólogos/técnicos de radiologia, enfermeiros, técnicos e auxiliares de enfermagem, entre outros. A análise dos dados envolveu estatística descritiva, testes não paramétricos e o uso de um modelo de regressão linear. O grau de confiabilidade do instrumento foi avaliado por meio do Coeficiente Alfa de Cronbach (α). O WHOQOL-bref demonstrou ser um instrumento adequado, de aplicação fácil e rápida para a aferição da qualidade de vida; mostrou bom desempenho psicométrico e boa consistência interna (α=0,884). O estudo permitiu conhecer a percepção de qualidade de vida do grupo estudado. / The main objective of this study was to evaluate the quality of life (QOL) of diagnostic radiology services workers at a hospital of São Paulo city. It aimed also to draw the profile of these workers identifying the variables, as its influence on their quality of life. A descriptive exploratory study with qualitative and quantitative approaches was carried out. The data were collected using the questionnaires: the abbreviated instrument for the assessment of the QOL, World Health Organization Quality of Life Instrument bref (WHOQOL-bref) and a questionnaire including the social demographic variables, work conditions and the variables that express the lifestyle of individuals, both questionnaires self-applied. The sample was formed by 118 workers, among them: physicians, technologists/technicians in radiology, nurses, technicians and assistants in nursing, and others health professionals. The data analysis included descriptive statistics, nonparametric tests and the use of a linear regression model. The reliability of the instrument for the studied sample was verified by Cronbachs Alpha Coefficient (α). The WHOQOL-bref proved to be an adequate instrument, with a good level of internal consistency (α=0.884), being easily and quickly administrated for the evaluation of the QOL. The study provided an overview of the perception of quality of life of the studied group.

Various hand-crafted features have been explored for medical image classification, which include SIFT and Local Binary Patterns (LBP). However, hand-crafted features may not be optimally discriminative for classifying images from particular domains (e.g. colonoscopy), as not necessarily tuned to the domain’s characteristics. In this work, I give emphasis on learning highly discriminative local features and image representations to achieve the best possible classification performance for medical images, particularly for colonoscopy and histology (cell) images. I propose approaches to learn local features using unsupervised and weakly-supervised methods, and an approach to improve the feature encoding methods such as bag-of-words. Unlike the existing work, the proposed weakly-supervised approach uses image-level labels to learn the local features. Requiring image-labels instead of region-level labels makes annotations less expensive, and closer to the data normally available from normal clinical practice, hence more feasible in practice. In this thesis, first, I propose a generalised version of the LBP descriptor called the Generalised Local Ternary Patterns (gLTP), which is inspired by the success of LBP and its variants for colonoscopy image classification. gLTP is robust to both noise and illumination changes, and I demonstrate its competitive performance compared to the best performing LBP-based descriptors on two different datasets (colonoscopy and histology). However LBP-based descriptors (including gLTP) lose information due to the binarisation step involved in their construction. Therefore, I then propose a descriptor called the Extended Multi-Resolution Local Patterns (xMRLP), which is real-valued and reduces information loss. I propose unsupervised and weakly-supervised learning approaches to learn the set of parameters in xMRLP. I show that the learned descriptors give competitive or better performance compared to other descriptors such as root-SIFT and Random Projections. Finally, I propose an approach to improve feature encoding methods. The approach captures inter-cluster features, providing context information in the feature as well as in the image spaces, in addition to the intra-cluster features often captured by conventional feature encoding approaches. The proposed approaches have been evaluated on three datasets, 2-class colonoscopy (2, 100 images), 3-class colonoscopy (2, 800 images) and histology (public dataset, containing 13, 596 images). Some experiments on radiology images (IRMA dataset, public) also were given. I show state-of-the-art or superior classification performance on colonoscopy and histology datasets.

A radiologia é especialidade médica mais informatizada, graças a difusão de protocolos e a digitalização dos processos. Com os avanços da tecnologia, o diagnóstico por imagens se mantém em constante evolução e tais mudanças nunca tiveram tanta repercussão sobre o trabalho dor profissionais de saúde como agora. Nosso desafio enquanto pesquisadores de computação é propor abordagens que facilitem o trabalho médico, instigue a colaboração e, por fim, como objetivo mais audacioso, melhore os cuidados à saúde das pessoas. Nesse contexto, esta dissertação investiga a inserção de interfaces alternativas para análise de imagens médicas diagnósticas. Ela está organizada em duas áreas principais, a primeira diz respeito ao diagnóstico móvel, desde o desenvolvimento de ferramentas que permitam o acesso a imagens digitais em ambientes com recursos limitados, até a avaliação do diagnóstico realizado nesses ambientes comparado a dispositivos tradicionais (workstations radiológicas). A segunda etapa está relacionada a visualização avançada de exames volumétricos, nesse caso investigamos a capacidade diagnóstica de visualizar em realidade virtual, bem como a qualidade das reconstruções nesse ambiente, usabilidade e desconfortos dos usuários. Toda a experimentação e desenvolvimento foi realizada sobre sistemas profissionais e validados por médicos especialistas em imagens diagnósticas. As principais contribuições referentes a aplicações móveis são técnicas para acesso eficiente a imagens médicas em ambientes com recursos limitados, como tablets e smartphones, um estudo do comportamento típico de médicos radiologistas ao utilizarem um visualizador móvel e as respectivas avaliações de usabilidade dessa aplicação. Para o diagnóstico móvel, destaca-se a alta taxa de acerto para avaliação de exames de tomografia computadorizada (TC), ressonância magnética (RM) e radiografias, quando comparado a computadores desktop. Além disso, resultados obtidos na visualização de imagens médicas em realidade virtual mostraram uma alta taxa de acerto na identificação de fraturas expostas (para imagens 3D de TC). A percepção dos radiologistas após utilizar a aplicação imersiva trouxe indicativos de quais áreas da medicina a realidade virtual pode trazer reais benefícios, como no planejamento de cirurgias, visualização de fraturas complexas, distração de pacientes em procedimentos dolorosos, entre outros. À luz dos resultados apresentados, verifica-se o potencial dos dispositivos móveis para avaliação de imagens diagnósticas, principalmente em casos de emergência, sendo fundamental para agilidade no cuidado à saúde de pacientes. A realidade virtual na radiologia tem o potencial de revolucionar as interfaces para manipulação de dados clínicos, criando uma novo paradigma de interpretação em imagens médicas diagnósticas. / Radiology is considered the most digital medical specialty because of the diffusion of protocols and the digitization of processes. With fast technological advances, the imagingbased diagnosis remains in constant evolution and such changes have never had as much repercussion on the health workers as today. Our challenge as computer scientists is to propose new approaches that facilitate medical work, instigate collaboration and, finally, as the most audacious goal, improve people’s healthcare. In such context, this thesis investigates the use of alternative interfaces for medical images analysis. Our research is organized in two main areas. The first one concerns mobile diagnosis, from the development of tools that allow access to medical images in computation environments with limited resources, to the evaluation of the diagnosis performed in these environments when compared to traditional devices (radiological workstations). The second stage is related to advanced approaches to visualize volumetric exams. In this case, we investigate the diagnostic capability of visualizing in virtual reality, as well as the quality of the reconstructions provided in such environments, usability and user discomforts. All the experimentation and development were carried out on professional systems and validated by specialists in diagnostic imaging. Techniques for efficient medical images access in environments with limited resources, such as tablets and smartphones, are the main contributions regarding mobile applications. This also includes a study of the typical behavior of radiologist physicians when using a mobile viewer and the respective usability evaluations of that application. For the mobile diagnosis, the high accuracy rate for the evaluation of computed tomography (CT), magnetic resonance imaging (MRI) and radiography when compared to desktop computers, stands out. In addition, results obtained in the virtual reality visualization showed a highly accurate rate for the identification of superficial fractures (in 3D CT studies). The radiologists perception after using the immersive application has brought indications of what areas in medicine virtual reality can bring real benefits. Examples include surgeries planning, visualization of complex fractures and distraction of patients in painful procedures, among others. In light of the presented results, the potential of the mobile devices for the evaluation of diagnostic images, mainly in cases of emergency, being fundamental for agility in the patients health care is noticeable. Virtual reality in radiology has the potential to revolutionize the interfaces for manipulation of clinical data, creating a new paradigm of interpretation in diagnostic medical images.

This thesis proposes a multidirectional methodological framework for a comprehensive ergonomic analysis and modelling of workflow for multi-modal vascular image-guided procedures (IGPs). Two approaches are employed to analyse the workflow: Discrete Event Simulation (DES) and purpose-oriented physical models. In contrast to previous studies, the proposed methodology looks in detail the actions carried out within the intervention rooms and the clinical experience during the procedures with three main objectives: to provide a deeper understanding of vascular procedures, to predict the impact of protocol modifications and to offer a framework to develop new image-guided protocols for the alternative use of Magnetic Resonance (MR) imaging in comparison with X-Ray Digital Subtraction Angiography (DSA). The methodological framework includes an assessment of commercial simulation software packages to evaluate their fitness to the specific requirements of this research. The novel methodology is applied to several cases studies of common vascular IGPs. In addition, a case of MR – guided focused ultrasound intervention demonstrates how it is possible to extend the framework to study non-vascular IGPs. The multi-disciplinary methodological framework described opens a new way to understand IGPs that could be used in prospective applications such as medical education and medical devices regulations.

The primary purpose of this study was to investigate the admission/selection process of the Radiologic Technology Program at East Tennessee State University to ascertain predictive validity of the admission process and to identify specific indicators leading to program completion. The population for this investigation consisted of 510 students who had applied to East Tennessee State University and the Radiologic Technology Program from 1991 through 1993. Data were collected from institutional and program academic records. Correlation research was chosen to establish validity. One-way Analysis of Variance and t-test were applied to investigate different admission parameters and discriminate analysis was completed due to prior groupings in the initial academic analysis. An alpha level of.05 was selected for this study. The population (N = 510) consisted of four groups of students: Program completers (graduates), program non-completers, students interviewed/not admitted, and students not interviewed nor admitted. One way analysis of variance (ANOVA) determined significant differences in all admission parameters between the four groups. Discriminate analysis of program completers and non-completers found that curriculum GPA ranking was significant explaining 47% of the shared variance. The population of students admitted to the program (N = 110) was further statistically analyzed by t-Tests and no significant differences were identified between program completers and non completers. Based on the findings, the following conclusions were drawn: (1) The admission parameters utilized by the Radiologic Technology Program at East Tennessee State University were statistically significant in identifying differences among the four groups of students; (2) No significant differences were identified between program completers and non-completers; (3) The admission model utilized by the Radiologic Technology Program is equitable. The following recommendations were suggested: (1) Further studies should be conducted incorporating demographic factors; (2) Studies addressing selection parameter reliability should be conducted; (3) Reliability of each interview question should be ascertained; (4) Studies involving common admission parameters at different sponsoring institutions should be investigated, and (5) Incorporation of qualitative methodology regarding program completion versus non-completion could be beneficial.

Bakgrund: Utvecklingen av genomlysnings-baserade interventioner har varit framgångsrika de senaste årtiondena, då det gäller behandling av patienter. Införandet av genomlysning har dock medfört risker, för både patient och personal. Detta på grund av att stråldoser ökat i takt med en större efterfrågan på genomlysning och en utveckling av mer avancerade undersökningar. Med tanke på att stråldosen från intervention har en biologisk långtidseffekt, så är strålskydd ett upp-märksammat och återkommande ämne då det påverkar både sjukvårdspersonal, patienter och sam-hället. Brist på strålskydd och oaktsamhet hos operatörerna medför en ökad risk för strålningsindu-cerade skador. Eftersom antalet interventioner ständigt ökar så behövs även en ökad medvetenhet hos vårdpersonal kring vilka risker strålningen kan medföra och hur de kan undvikas. Syfte: Att beskriva vilka åtgärder som kan vidtas för att minska stråldosen för personal och patient vid angiografi/intervention. Metod: En systematisk litteraturstudie har använts. Resultat: I det sammanställda resultatet har flera olika strålskyddsåtgärder presenterats för att reducera stråldosen under intervention/angiografi. Genomlysningstid, modern teknik, uppdaterade inställningar i apparaturen och blyskydd har alla visat sig minska stråldosen markant till patient och personal. Utbildning och feedback ses även vara en viktig del i strålskyddsarbetet då det utgör grun-den för att riktlinjer kring strålskydd följs. Slutsats: Att det finns alternativa strålskyddsåtgärder vid IR- undersökningar/åtgärder är något som kan konstateras. Faktum är att en kombination av dessa åtgärder helt klart vore optimalt, för ökad säkerhet hos både personal och patienter vid exponering av strålning. / Background: The development of fluoroscopy-guided interventions the recent decades has resulted in a successful treatment of patients. However, the introduction of these diagnostic devices carry risks for both patients and staff. This is due to the fact that radiation doses increases in line with a greater demand for interventions and the development of advanced procedures. The radiation may cause long-term biological effects which makes radiation protection an important subject as it affects both staff, patients and society. Lack of radiation protection and negligence among operators cause an increased risk of radiation-induced damage. As the number of interventions constantly increase, improved knowledge is needed. Aim: The aim of this study is to describe which methods can be applied in order to reduce radiation doses for staff and patients in angiography / intervention. Method: A systematic study of existing literature. Results: The result shows several different radiation protection strategies to reduce the radiation dose during intervention / angiography. Fluoroscopy time, modern technology, updated settings in the device and lead protection have all been shown to reduce radiation dose significantly to both patients and staff. Education and feedback are also considered to be an important part of the radiation safety as they provide the basic guidelines on radiation protection. Conclusion: There is a lot of alternative radiation protection strategies in fluoroscopy-guided inter-ventions. In fact, a combination of these strategies would clearly be optimal for increased safety for both staff and patients exposed to radiation.

Low back pain has a significant impact on global public health and economics. The bright facet sign (BFS), a common finding on magnetic resonance imaging (MRI) of the lumbar spine, is associated with low back pain. While degenerative joint disease (DJD) affects low back pain, its presence appears independent of the BFS at the disc and facet joints at the same spinal level. Increased BMI, considered a risk factor for DJD, has an inverse association with the BFS. The independent relationship of DJD and the BFS is poorly understood and may represent a previously unreported pain pathway. In this nested case-control quantitative study, based on an accepted conceptual framework, 350 lumbar MRI studies on symptomatic patients with historic and anthropomorphic data related to low back pain were analyzed using Spearman's Rho and Multivariate Logistic Regression to examine any associations between the BFS at 3 spinal levels and the independent variables age, race/ethnicity, physical activity, BMI, trauma, low back pain, and DJD. The findings revealed significant associations between the BFS and the duration of pain, age, and gender at 1 or more spinal levels, the BFS and BMI and degenerative facet disease (DFD) at all 3 spinal levels, and no association between the BFS and degenerative disc disease (DDD). These results, contrary to current medical constructs where BMI, DFD, and DDD are considered predictive of low back pain, facilitate an improved understanding of joint function and contribute to the current body of knowledge related to low back pain. An understanding of the BFS as it relates to DJD and low back pain will assist clinicians with the early detection of spinal degeneration and the mitigation of pain and suffering, contributing to positive social change.

Objectives: To evaluate the influence of five different displays on the diagnosis of artificial caries-like lesions on restored and unrestored tooth surfaces. Materials & Methods: 60 extracted human teeth (30 premolars and 30 molars) were selected. All molars had class II cavities prepared and restored. Half of the premolars and molars were randomly selected and a 7mm² area was exposed to a demineralizing solution for 120 days. Phantoms with four teeth (two premolars and two molars) were created. Periapical radiographs were obtained on RVG 6100 digital sensor (Kodak Dental Systems, New York, USA). The images were evaluated under subdued lighting on five viewing displays (Barco MDNC-3321, NEC Wide, Apple iPad Pro, Microsoft Surface Pro 4 and Dell flat panel monitor) by three observers using a five-point rating scale. Sensitivity (Sn), specificity (Sp), accuracy (Ac) and Receiver Operating Characteristic (ROC) curves and their areas under the curves (AUC) were calculated and compared by Analysis of variance and post-hoc Tukey test. Intraobserver and interobserver agreement were accomplished after a three month interval observational.. The observer agreement was evaluated with the Cohen’s kappa test. Results: Even though the tablets slightly improved accuracy over the medical monitors, there was no statistically significant difference in sensitivity, specificity, accuracy or AUC among the five monitors when the same tooth group was considered (p< 0.05) with the exception of the iPad Pro which had a specificity p-value of 0.014 when comparing the two materials within the iPad Pro. Conclusion: There is no perceivable disadvantage to utilizing a higher resolution tablet viewing platform for plane images. No advantage to the medical grade monitors over the tablets or the consumer monitor. Both tablets improved detection accuracy on the unrestored premolars. However further evaluation especially in a clinical lighting setting is warranted to evaluate a displays impact on observer performance within common clinical practice lighting parameters.

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