Biological systems of bacteria were investigated at the single-cell and single-molecule level. Additionally, aspects of the techniques employed were studied. A unifying theme in each project is the reliance on optical imaging techniques coupled to microfluidic devices. Hypo-osmotic shock experiments with an Escherichia coli mechanosensitive channel deletion mutant were carried out at the single-cell level. E. coli MJF465 cells in which the three major mechanosensitive channel genes are deleted (∆mscL, ∆mscS, ∆mscK) show only 10% cell viability upon hypo-osmotic shock (from LB + 0.5 M NaCl into distilled water), compared to 90% viability of the wild-type strain. Bacterial cells were trapped with optical tweezers in microfluidic devices, enabling the first direct observation of single-cell behaviour upon hypo-osmotic shock. Phase-contrast microscopy revealed intra-population diversity in the cells response: Different features of lysis included cells bursting rapidly and leakage of ribosomes, DNA and protein from the cytoplasm. Fluorescence microscopy of hypo-osmotically-shocked GFP-expressing MJF465 cells showed either bursting of cells, which was a rare event, or fast leakage of GFP, indicating cell membrane ruptures. Data were analysed in terms of their kinetic behaviour and showed that lysis occurs on a timescale of milliseconds to seconds. The implications of these findings for the bacterial cell wall and cell membranes are discussed. Enzymes involved in homologous recombination and repair of double-stranded DNA (dsDNA) breaks are essential for maintaining genomic integrity in both eukaryotes and prokaryotes. RecBCD of E. coli and AddAB, found widely in bacteria, are involved in these processes, carrying out the same function. Both enzymes were studied kinetically with single-molecule total internal reflection fluorescence microscopy (TIRFM). Surface-tethered, hydrodynamically stretched lambda-DNA molecules, stained with YOYO-1, were imaged with TIRFM in a microfluidic flowcell. The RecBCD enzyme is a well characterised DNA helicase and was introduced to this system for method validation purposes. The AddAB enzyme of Bacteroides fragilis was then characterised as a helicase acting on lambda-DNA. It was found that AddAB helicase unwinds dsDNA with high processivity of on average 14,000 bp and up to 40,000 bp for individual enzyme complexes at an ATP-dependent rate ranging from 50-250 bp s−1 (for Mg2+-ATP concentrations larger or equal than 0.1 mM). This activity was detected by DNA binding dye (YOYO-1) displacement from the dsDNA and studied for different Mg2+-ATP concentrations, flow (shear) rates and different YOYO-1 staining ratios of DNA. Aspects of this last experimental setup were investigated. A kinetic analysis of intercalation of YOYO-1 into lambda-DNA is presented, occurring on a timescale of minutes. Different flow rates and staining ratios that influence the apparent (stretched) DNA molecule length were also examined. Several image analysis techniques were employed to enhance the data quality in images showing stretched lambda-DNA molecules. The Singular Value Decomposition was found to be the most effective technique which strongly reduces the noise in the obtained kymograph images.

O presente estudo teve por objetivo classificar, em tabelas de pontuação, as lesões articulares encontradas em equinos submetidos à artroscopia e correlacionar os escores com sua evolução após tratamento. Foram analisadas, de forma prospectiva, articulações tibiotársicas e metacarpo/metatarsofalangeanas de equinos de esporte encaminhados ao HOVET-USP. Cada articulação foi pontuada em tabelas de escore relacionadas a anamnese, e exames físico, ultrassonográfico, radiográfico e artroscópico. As pontuações foram somadas, determinando-se um escore por exame para cada articulação. A pontuação das imagens radiográficas e artroscópicas foram realizadas por estudo encoberto de três e quatro avaliadores, respectivamente. O proprietário ou médico veterinário responsável pelo animal respondeu a questionário relacionado à evolução do quadro e este foi correlacionado aos escores alcançados pela articulação, determinando-se o prognóstico para os escores. Foram avaliadas 78 articulações tibiotársicas e 48 metacarpo/metatarsofalangeanas. As pontuações mais frequentes na anamnese(>50%) foram as relacionadas ao início do quadro ou animais encaminhados por achados radiográficos ao exame pré-venda. Ao exame físico mais de 50% das articulações apresentaram claudicação, positividade ao teste de flexão, diminuição do ângulo máximo de flexão articular e aumento de temperatura articular externa. No exame radiográfico as alterações mais frequentes foram o aumento de volume de partes moles (37,4%) a presença de esclerose (40%) e osteólise do osso subcondral (67%), e fragmentos osteocondrais únicos evidentes (47,3%) com medidas abaixo de 5mm (30%). A ultrassonografia demonstrou alterações mais frequentes relacionadas ao líquido sinovial segundo seu aspecto, com predominância de material amorfo (33,1%) e quantidade aumentada em até a metade do volume fisiológico (40%), além da irregularidade do osso subcondral (41,3%). A presença de vasos sanguíneos evidentes (65,8%), do aumento volume e na quantidade das vilosidades da membrana sinovial (50%) e na presença de fibrilação (75,8%), fissuras (54,2%) e erosão superficial (70%) da cartilagem foram as alterações mais encontradas ao exame artroscópico, onde observaram-se, também, os fragmentos osteocondrais únicos (61,7%) e fixados ao local da lesão (86,7%). Os valores médios do escore radiográfico foram maiores (p=0,05) para as lesões palmares/plantares dos boletos (11,33±5,03) e para as articulações tibiotársicas (11,27±4,32) do que para as lesões dorsais dos boletos (9,18±3,5). As lesões nos boletos, dorsais (7,16±4,83) ou palmares/plantares (8,33±5,27) obtiveram médias de escore maiores (p=0,011) ao exame ultrassonográfico do que as tibiotársicas (5,65±3,36) e o inverso aconteceu na artroscopia com a média das tibiotársicas (12,96±6,22) superiores (p<0,001) às dos boletos (8,51±3,61) lesões dorsais ou lesões palmares/plantares (7,26±2,77). Houve concordância entre os avaliadores do exame radiográfico para as articulações tibiotársicas, e boletos com lesão dorsal e palmar/plantar. Mas apenas nas metacarpo/metatarsofalangeanas dorsais e palmares/plantares entre os avaliadores da artroscopia. A regressão logística mostrou que os escores relacionados à anamnese (1,178), exame ultrassonográfico (1,193) e artroscópico (1,213) determinam a chance de insatisfação do proprietário (acurácia de 80%). E sugere a utilização de calculadora para a obtenção da chance de insatisfação do proprietário para novos casos. Assim, concluiu-se que, as tabelas para normatização e pontuação aplicadas possibilitaram a determinação de escores para os exames realizados de forma satisfatória. Permitindo correlaciona-los com a chance de insatisfação frente o resultado atingido após o tratamento. / This study aimed to classify joint damage in horses undergoing arthroscopy, using a scoring matrix, and correlating scores with post-treatment recovery. We prospectively analyzed tibiotarsal and metacarpophalangeal/metatarsophalangeal joints of athletic horses referred for arthroscopy to the Veterinary Hospital of the University of São Paulo. Each joint was ranked based on anamnesis-related scoring tables, as well as physical, ultrasound, radiographic and arthroscopic examinations. Scores were summarized to determine a ranking for each joint examined. Three and four blind assessors performed scoring of radiographic and arthroscopic images, respectively. The animals owner or responsible veterinarian answered a report related to the disease progression and this was correlated to the joint assessment score, determining a prognosis for joint scores. Seventy-eight tibiotarsal joints and 48 metacarpophalangeal/metatarsophalangeal were evaluated. The most common anamnesis scores (> 50%) were related to the onset of symptoms or pre-purchase radiographic findings. During physical examination, over 50% of the joints induced lameness, positive results to flexion tests, reduced joint maximum flexion angles and increased superficial joint temperature. During radiographic examination, frequently noticed alterations were increased volume of soft tissues (37.4%), the presence of sclerosis (40%), osteolysis of the subchondral bone (67%), and evident osteochondral fragments (47.3%) measuring below 5mm (30%). Ultrasonography showed more frequent changes related to synovial fluid according to appearance, with a predominance of amorphous material (33.1%) and increases of up to half in physiological volume (40%) amount, in addition to irregularity of the subchondral bone (41.3 %). Most-found alterations noticed during arthroscopic examination were the presence of apparent blood vessels (65.8%), increased volume and quantity of synovial membrane villi (50%), the presence of cartilage fibrillation (75.8%), fissures (54.2%), cartilage surface erosion (70%), unique (61.7%) and non-displaced osteochondral fragments (86.7%). The mean values of radiographic scores were higher (p = 0.05) for lesions of the fetlock palmar/plantar (11.33 ± 5.03) and tibiotarsal joints (11.27 ± 4.32) than for dorsal fetlock (9.18 ± 3.5). Lesions in the fetlock, dorsal (7.16 ± 4.83) or palmar/plantar (8.33 ± 5.27) had higher mean scores (p = 0.011) during ultrasound examination than the tibiotarsal (5.65 ± 3.36), while the reverse was observed in arthroscopy with the tibiotarsal average higher (12.96 ± 6.22, p <0.001) than fetlock dorsal (8.51 ± 3.61) or palmar/plantar lesions (7.26 ± 2.77). There was general agreement among radiographic examination evaluators for tibiotarsal joints, and dorsal and palmar fetlock lesions. However, arthroscopy evaluators agreed only on metacarpal/metatarsophalangeal, dorsal and palmar/plantar. Logical regression showed that the scores related to anamnesis (1,178), ultrasonography (1,193) and arthroscopy (1,213) correlated to the owners dissatisfaction (80% accuracy), and suggests the use of a score calculator for obtaining the chance of dissatisfied owners for new cases. Thus, it was concluded that, the tables and classifications proposed for anamnesis, physical, radiographic, ultrasonographic and arthroscopic examination enabled a useful score determination allowing correlation between the joint score and owners dissatisfaction with the outcome of arthroscopic treatment of non-infectious joint diseases in horses.

Parmi les diverses méthodes d’imagerie médicales, les méthodes d’imagerie optique connaissent depuis une vingtaine d’années un développement significatif. Parmi les techniques d’imagerie optique récemment mises en œuvre, la Tomographie Optique Cohérente Plein Champ – ou OCT Plein Champ – présente des caractéristiques remarquables, en particulier en termes de résolution et de simplicité instrumentale, permettant d’envisager son application au domaine du diagnostic du cancer. Cette thèse décrit la conception et la mise en œuvre de dispositifs d’OCT Plein Champ pour utilisation en contexte clinique, afin d’évaluer la performance de la technique pour le diagnostic peropératoire du cancer, en vue de son amélioration et optimisation. Dans cet objectif nous avons réalisé des travaux regroupés en 2 axes : Une partie translationnelle, consistant à développer un dispositif de microscopie optique par OCT Plein Champ répondant au besoin clinique pour le diagnostic peropératoire du cancer sur biopsies, en vue de l’évaluation de ses performances de diagnostic sur plusieurs problématiques cliniques : le diagnostic peropératoire du tissu mammaire, de résection de cerveau, ainsi que la qualification préopératoire de greffons cornéens. Une partie exploratoire, principalement instrumentale, dédiée à l’amélioration des performances de diagnostic de la technique, proposant de nouvelles approches multimodales (contraste de fluorescence, contraste dynamique) et multi-échelles, ou encore la déclinaison du dispositif sous la forme d’un endoscope rigide portable utilisable en contexte clinique. / Among medical imaging techniques, optical imaging methods have been significantly developped during the past decades. More specifically, among recently proposed optical imaging techniques, Full-Field Optical Coherence Tomography – or FFOCT – provides unique capabilities, in particular regarding resolution and instrumental simplicity, which allows to consider its application to cancer diagnosis. This thesis demonstrates the design and implementation of new FFOCT devices for use in a clinical context, targeting improvement and optimization of the technique. Two major development parts have been realized : A translational part, comprising the development of a FFOCT microscope adapted to a clinical use for intraoperative diagnosis of cancer on tissue biopsies, and the assessment of its diagnosis performance for several clinical cases : the intraoperative diagnosis of breast tissue, of brain resections, and the preoperative qualification of corneal grafts. A research part - mainly instrumental - targeting the improvement of the diagnosis performance of the technique, based on new multimodal (fluorescence contrast, dynamic contrast) and multiscale approaches, or on the miniaturization of the device by developing a handheld rigid endoscope for clinical use.

Thesis (M.Sc.). / Written for the Medical Physics Unit. Title from title page of PDF (viewed ). Includes bibliographical references.

Cutaneous malignancies represent a quarter of all new cancer diagnoses in the UK. The key to reducing the tumours’ associated mortality and morbidity is early diagnosis and treatment. Prompt diagnosis remains predominately a clinical skill, but relatively little investigation of the cognitive psychology underpinning expertise in this domain has been undertaken. This thesis aims to improve understanding of these processes and investigate how lesional diagnostic expertise might be enhanced. A large database of diagnostically tagged images was captured specifically for this project. A series of separate studies were undertaken to give insight into how lesional diagnosis occurs and how it can be improved. The studies highlighted that non-analytical pattern recognition (NAPR) is likely to predominate in distinguishing malignant and non-malignant skin lesions and that the widely-promoted rules advocating analytical pattern recognition (APR) are not effective for discriminating melanoma from benign pigmented lesions. The keystone to promoting the development of NAPR and thus diagnostic expertise would seem to be increasing a novice’s personal library of examples with relevant feedback. Studies demonstrated that current undergraduate exposure was variable but universally sparse, so simulation by way of diagnostically tagged images was developed which showed accuracy could be improved by increased exposure. This improvement occurred in both a content specific and dose responsive manner. These studies also highlighted that the learning curves for skin lesions are not uniform. Further studies demonstrated that the choice of images had implications on the development of diagnostic expertise; suggesting it was important that these images represent clinical practice rather than “classic” examples traditionally advocated for teaching purposes. In addition, studies highlighted the potential benefit of the 3D models developed during this project. Building on the idea that a personal catalogue of relevant referent images was crucial to enhanced diagnostic accuracy, prototype software was developed to exteriorise the experts’ library of examples; in the tests described novices utilising the software delivered superior accuracy than medical students on the completion of their undergraduate teaching. In summation, the work described shows that by utilising dermato-informatic approaches lesional diagnostic competence can be improved significantly.

O presente estudo teve por objetivo classificar, em tabelas de pontuação, as lesões articulares encontradas em equinos submetidos à artroscopia e correlacionar os escores com sua evolução após tratamento. Foram analisadas, de forma prospectiva, articulações tibiotársicas e metacarpo/metatarsofalangeanas de equinos de esporte encaminhados ao HOVET-USP. Cada articulação foi pontuada em tabelas de escore relacionadas a anamnese, e exames físico, ultrassonográfico, radiográfico e artroscópico. As pontuações foram somadas, determinando-se um escore por exame para cada articulação. A pontuação das imagens radiográficas e artroscópicas foram realizadas por estudo encoberto de três e quatro avaliadores, respectivamente. O proprietário ou médico veterinário responsável pelo animal respondeu a questionário relacionado à evolução do quadro e este foi correlacionado aos escores alcançados pela articulação, determinando-se o prognóstico para os escores. Foram avaliadas 78 articulações tibiotársicas e 48 metacarpo/metatarsofalangeanas. As pontuações mais frequentes na anamnese(>50%) foram as relacionadas ao início do quadro ou animais encaminhados por achados radiográficos ao exame pré-venda. Ao exame físico mais de 50% das articulações apresentaram claudicação, positividade ao teste de flexão, diminuição do ângulo máximo de flexão articular e aumento de temperatura articular externa. No exame radiográfico as alterações mais frequentes foram o aumento de volume de partes moles (37,4%) a presença de esclerose (40%) e osteólise do osso subcondral (67%), e fragmentos osteocondrais únicos evidentes (47,3%) com medidas abaixo de 5mm (30%). A ultrassonografia demonstrou alterações mais frequentes relacionadas ao líquido sinovial segundo seu aspecto, com predominância de material amorfo (33,1%) e quantidade aumentada em até a metade do volume fisiológico (40%), além da irregularidade do osso subcondral (41,3%). A presença de vasos sanguíneos evidentes (65,8%), do aumento volume e na quantidade das vilosidades da membrana sinovial (50%) e na presença de fibrilação (75,8%), fissuras (54,2%) e erosão superficial (70%) da cartilagem foram as alterações mais encontradas ao exame artroscópico, onde observaram-se, também, os fragmentos osteocondrais únicos (61,7%) e fixados ao local da lesão (86,7%). Os valores médios do escore radiográfico foram maiores (p=0,05) para as lesões palmares/plantares dos boletos (11,33±5,03) e para as articulações tibiotársicas (11,27±4,32) do que para as lesões dorsais dos boletos (9,18±3,5). As lesões nos boletos, dorsais (7,16±4,83) ou palmares/plantares (8,33±5,27) obtiveram médias de escore maiores (p=0,011) ao exame ultrassonográfico do que as tibiotársicas (5,65±3,36) e o inverso aconteceu na artroscopia com a média das tibiotársicas (12,96±6,22) superiores (p<0,001) às dos boletos (8,51±3,61) lesões dorsais ou lesões palmares/plantares (7,26±2,77). Houve concordância entre os avaliadores do exame radiográfico para as articulações tibiotársicas, e boletos com lesão dorsal e palmar/plantar. Mas apenas nas metacarpo/metatarsofalangeanas dorsais e palmares/plantares entre os avaliadores da artroscopia. A regressão logística mostrou que os escores relacionados à anamnese (1,178), exame ultrassonográfico (1,193) e artroscópico (1,213) determinam a chance de insatisfação do proprietário (acurácia de 80%). E sugere a utilização de calculadora para a obtenção da chance de insatisfação do proprietário para novos casos. Assim, concluiu-se que, as tabelas para normatização e pontuação aplicadas possibilitaram a determinação de escores para os exames realizados de forma satisfatória. Permitindo correlaciona-los com a chance de insatisfação frente o resultado atingido após o tratamento. / This study aimed to classify joint damage in horses undergoing arthroscopy, using a scoring matrix, and correlating scores with post-treatment recovery. We prospectively analyzed tibiotarsal and metacarpophalangeal/metatarsophalangeal joints of athletic horses referred for arthroscopy to the Veterinary Hospital of the University of São Paulo. Each joint was ranked based on anamnesis-related scoring tables, as well as physical, ultrasound, radiographic and arthroscopic examinations. Scores were summarized to determine a ranking for each joint examined. Three and four blind assessors performed scoring of radiographic and arthroscopic images, respectively. The animals owner or responsible veterinarian answered a report related to the disease progression and this was correlated to the joint assessment score, determining a prognosis for joint scores. Seventy-eight tibiotarsal joints and 48 metacarpophalangeal/metatarsophalangeal were evaluated. The most common anamnesis scores (> 50%) were related to the onset of symptoms or pre-purchase radiographic findings. During physical examination, over 50% of the joints induced lameness, positive results to flexion tests, reduced joint maximum flexion angles and increased superficial joint temperature. During radiographic examination, frequently noticed alterations were increased volume of soft tissues (37.4%), the presence of sclerosis (40%), osteolysis of the subchondral bone (67%), and evident osteochondral fragments (47.3%) measuring below 5mm (30%). Ultrasonography showed more frequent changes related to synovial fluid according to appearance, with a predominance of amorphous material (33.1%) and increases of up to half in physiological volume (40%) amount, in addition to irregularity of the subchondral bone (41.3 %). Most-found alterations noticed during arthroscopic examination were the presence of apparent blood vessels (65.8%), increased volume and quantity of synovial membrane villi (50%), the presence of cartilage fibrillation (75.8%), fissures (54.2%), cartilage surface erosion (70%), unique (61.7%) and non-displaced osteochondral fragments (86.7%). The mean values of radiographic scores were higher (p = 0.05) for lesions of the fetlock palmar/plantar (11.33 ± 5.03) and tibiotarsal joints (11.27 ± 4.32) than for dorsal fetlock (9.18 ± 3.5). Lesions in the fetlock, dorsal (7.16 ± 4.83) or palmar/plantar (8.33 ± 5.27) had higher mean scores (p = 0.011) during ultrasound examination than the tibiotarsal (5.65 ± 3.36), while the reverse was observed in arthroscopy with the tibiotarsal average higher (12.96 ± 6.22, p <0.001) than fetlock dorsal (8.51 ± 3.61) or palmar/plantar lesions (7.26 ± 2.77). There was general agreement among radiographic examination evaluators for tibiotarsal joints, and dorsal and palmar fetlock lesions. However, arthroscopy evaluators agreed only on metacarpal/metatarsophalangeal, dorsal and palmar/plantar. Logical regression showed that the scores related to anamnesis (1,178), ultrasonography (1,193) and arthroscopy (1,213) correlated to the owners dissatisfaction (80% accuracy), and suggests the use of a score calculator for obtaining the chance of dissatisfied owners for new cases. Thus, it was concluded that, the tables and classifications proposed for anamnesis, physical, radiographic, ultrasonographic and arthroscopic examination enabled a useful score determination allowing correlation between the joint score and owners dissatisfaction with the outcome of arthroscopic treatment of non-infectious joint diseases in horses.

Tendo em vista experimentos envolvendo o estudo da dinâmica de gases quânticos aprisionados, visando a simulação quântica de sistemas complexos, este trabalho discute a implementação e o estudo da técnica de imagem dispersiva, por contraste de fase, e a compara com o método de imagem por absorção óptica. A implementação da nova técnica foi feita em um regime não convencional de dessintonia, explorando a região proxima da ressonância atômica, onde se deve levar em conta o efeito da absorção, além da mudança de fase, do campo elétrico do laser de prova, após interagir com os átomos. Portanto, este trabalho apresenta não só a implementação de uma nova técnica experimental, mas também um modelo simples para interpretar os dados obtidos nesse novo regime. / Envisioning experiments involving the dynamics of trapped quantum gases, towards the quantum simulation of complex systems, this work presents the implementation and study of a dispersive imaging technique, by phase contrast, and compares it to absorption imaging. The implementation of this new technique in our laboratory was done in a non conventional range of detunings, exploring the region near atomic resonance, where absortion effecs need to be taken into account, in addition to the phase shift, introduced in the electric field of the probing laser, after interacting with the atoms. Therefore, this work presents not only the implementation of a new experimental technique, but also a simple model to interpret the dada obtained in this new regime.

A retinografia e angiografia digital são técnicas de observação e captura de imagens do fundo do olho que permitem o diagnóstico de diversas patologias. O aperfeiçoamento dos retinógrafos digitais, viabilizado pelos avanços tecnológicos observados nas últimas décadas, tornou possíveis modificações sistêmicas inovadoras como a apresentada e discutida neste trabalho. O principal objetivo é avaliar comparativamente a resolução espacial de imagens captadas com uma configuração que utiliza apenas um sensor monocromático e um conjunto de LEDs cromáticos, com imagens geradas por um sensor com filtro cromático integrado. A proposta é suportada por resultados teóricos que indicam um desempenho superior do uso de sensores monocromáticos em retinografia. Para validação da nova metodologia o sistema descrito foi montado e várias fotos da retina foram capturadas. Todo o processo de imageamento do fundo do olho é descrito, incluindo rotinas de software que precisaram ser criadas em decorrência das inovações. A partir das imagens capturadas foram aplicadas técnicas de avaliação global de maneira que as previsões teóricas puderam ser verificadas. Por fim são apresentadas conclusões sobre o desempenho global do sistema e adicionados tópicos como sugestões para continuidade futura do trabalho. / The digital retinography and angiography are techniques to observe and capture images of the eye fundus that allows the diagnosis of several diseases. The improvements of digital fundus camera made possible by technological advances seen in recent decades have made possible innovative systemic changes, as the presented and discussed in this work. The main objective is to comparatively evaluate the spatial resolution of images captured with a configuration that uses only a monochrome sensor and a set of chromatic LEDs, with images generated by a sensor with integrated color filter. The proposal is supported by theoretical results that indicate a superior performance when using a monochrome sensor to get fundus images. To validate the new methodology, the system described was assembled and several retina pictures were taken. The whole process of imaging the eye fundus is described, including software procedures that had to be created as a consequence of the innovations. From the images captured, overall evaluation techniques have been applied, so that theoretical forecasts could be verified. Finally, conclusions are presented on the overall performance of the system and suggestions for topics for future work were added.

Abstract not available. / by Wong Lai-hung, Grace. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 218-252). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.

A retinografia e angiografia digital são técnicas de observação e captura de imagens do fundo do olho que permitem o diagnóstico de diversas patologias. O aperfeiçoamento dos retinógrafos digitais, viabilizado pelos avanços tecnológicos observados nas últimas décadas, tornou possíveis modificações sistêmicas inovadoras como a apresentada e discutida neste trabalho. O principal objetivo é avaliar comparativamente a resolução espacial de imagens captadas com uma configuração que utiliza apenas um sensor monocromático e um conjunto de LEDs cromáticos, com imagens geradas por um sensor com filtro cromático integrado. A proposta é suportada por resultados teóricos que indicam um desempenho superior do uso de sensores monocromáticos em retinografia. Para validação da nova metodologia o sistema descrito foi montado e várias fotos da retina foram capturadas. Todo o processo de imageamento do fundo do olho é descrito, incluindo rotinas de software que precisaram ser criadas em decorrência das inovações. A partir das imagens capturadas foram aplicadas técnicas de avaliação global de maneira que as previsões teóricas puderam ser verificadas. Por fim são apresentadas conclusões sobre o desempenho global do sistema e adicionados tópicos como sugestões para continuidade futura do trabalho. / The digital retinography and angiography are techniques to observe and capture images of the eye fundus that allows the diagnosis of several diseases. The improvements of digital fundus camera made possible by technological advances seen in recent decades have made possible innovative systemic changes, as the presented and discussed in this work. The main objective is to comparatively evaluate the spatial resolution of images captured with a configuration that uses only a monochrome sensor and a set of chromatic LEDs, with images generated by a sensor with integrated color filter. The proposal is supported by theoretical results that indicate a superior performance when using a monochrome sensor to get fundus images. To validate the new methodology, the system described was assembled and several retina pictures were taken. The whole process of imaging the eye fundus is described, including software procedures that had to be created as a consequence of the innovations. From the images captured, overall evaluation techniques have been applied, so that theoretical forecasts could be verified. Finally, conclusions are presented on the overall performance of the system and suggestions for topics for future work were added.