Enhanced visualization of retinal pathologies with ultrahigh resolution optical coherence tomography

Thesis (Ph. D.)--Harvard-MIT Division of Health Sciences and Technology, 2005.Page 150 blank.Includes bibliographical references.Current clinical practice calls for the development of techniques to diagnose diseases in its early stages, when treatment is most effective and significant irreversible damage can either be prevented or delayed. Optical coherence tomography (OCT) is an emerging medical diagnostic technology being investigated for applications in a number of medical fields including ophthalmology, cardiology, and gastroenterology. OCT is analogous to ultrasound except that it uses light waves rather than sound waves. OCT can achieve a much higher resolution than ultrasound in measuring the underlying tissue microstructures. Another advantage of OCT is that it can achieve imaging in a non-contact and non-invasive manner. With typical axial resolution of 10 [mu]m, OCT already provides significantly more detailed structural information than any other conventional clinical imaging technique. The development of OCT with even higher resolution would potentially have significant impact in diagnosing diseases in such fields as ophthalmology, cardiology, gastroenterology, and oncology. Ultrahigh resolution OCT systems have been developed for animal research and clinical ophthalmology. Ultrahigh resolution OCT improves the axial resolution of OCT from the standard 10 [mu]m to 1 [mu]m for animal studies and 3 [mu]m for clinical studies. This improved imaging resolution approaches that of histopathology. Therefore, OCT can potentially function as "optical biopsy" since it permits the imaging of tissue microstructure with resolutions approaching that of histopathology except that imaging can be performed in real time, without the need of tissue removal.(cont.) Using ultrahigh resolution OCT systems, animal imaging studies have been performed on mouse and rat models of retinal diseases and clinical imaging studies have been performed on more than 800 patients at the ophthalmology clinic. The results from patient imaging studies on a wide variety of retinal diseases suggest that ultrahigh resolution OCT can improve the diagnosis and management of retinal diseases as well as possibly increase the understanding of ocular disease pathogenesis. Therefore, ultrahigh resolution OCT has the potential to become an important tool in ophthalmology research and clinics.by Tony Hong-Tyng Ko.Ph.D

Human-Centric Machine Vision

Recently, the algorithms for the processing of the visual information have greatly evolved, providing efficient and effective solutions to cope with the variability and the complexity of real-world environments. These achievements yield to the development of Machine Vision systems that overcome the typical industrial applications, where the environments are controlled and the tasks are very specific, towards the use of innovative solutions to face with everyday needs of people. The Human-Centric Machine Vision can help to solve the problems raised by the needs of our society, e.g. security and safety, health care, medical imaging, and human machine interface. In such applications it is necessary to handle changing, unpredictable and complex situations, and to take care of the presence of humans

Bio-imaging and serum analysis of zinc and other trace elements in a study of age-related diseases using inductively-coupled plasma mass spectrometry

Trace elements participate in numerous biological processes and understanding their activity is essential in monitoring various diseases. Zinc has long been recognized as a fundamental component of various tissues, being highly concentrated in the retina and an essential structural component of many proteins. It plays a crucial role in many biological activities including homeostasis, immune function, oxidative stress, and aging disorders. During aging, the systemic metabolism of iron, zinc and copper changes, and this disruption in metal homeostasis appears to be associated with age-related disorders such as Alzheimer s disease (AD) and Age related macular degeneration (AMD). As understanding the role of these metals is critical in finding the underlying causes for such diseases, and providing proper diagnosis and treatments, the distribution of these crucial elements in AD and AMD has been investigated. A rapid, accurate technique using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) was developed for the preparation and analysis of small volume (30 µl) biological samples. Analytical performance was evaluated using Serum UTAK certified reference material and the method was applied to Zn, Cu and Fe determination in 81 human serum samples from AD and AMD patients. No significant difference was found in Zn and Cu levels between AD and AMD patients, whereas Fe in AMD patients was slightly higher than AD patients. The results showed a decrease in serum Zn and Fe, and a notable increase in serum Cu in both AD and AMD patients compared to healthy controls. Elemental bio-imaging using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was successfully employed for Zn imaging in 12 rat retina sections given either a conventional or a Zn-containing diet. A new data processing method, involving fitting Gaussian peaks to individual LA-ICP-MS line scans, was established. The RPE/retina peak area ratio was used to evaluate the differences in Zn content between supplemented and non-supplemented rats. In general, the difference between the three differentially fed rat groups was not statistically significant for the relatively small group of twelve rats investigated here. Thickness of Zn bands was also found to vary between controls and supplemented rats. This technique has the potential to support biologists in recognising possible new biomarkers for disease, related to specific trace elements

Automatic detection of drusen associated with age-related macular degeneration in optical coherence tomography: a graph-based approach

Tese de Doutoramento em Líderes para Indústrias TecnológicasThe age-related macular degeneration (AMD) starts to manifest itself with the appearance of drusen. Progressively, the drusen increase in size and in number without causing alterations to vision. Nonetheless, their quantification is important because it correlates with the evolution of the disease to an advanced stage, which could lead to the loss of central vision. Manual quantification of drusen is impractical, since it is time-consuming and it requires specialized knowledge. Therefore, this work proposes a method for quantifying drusen automatically In this work, it is proposed a method for segmenting boundaries limiting drusen and another method for locating them through classification. The segmentation method is based on a multiple surface framework that is adapted for segmenting the limiting boundaries of drusen: the inner boundary of the retinal pigment epithelium + drusen complex (IRPEDC) and the Bruch’s membrane (BM). Several segmentation methods have been considerably successful in segmenting layers of healthy retinas in optical coherence tomography (OCT) images. These methods were successful because they incorporate prior information and regularization. However, these factors have the side-effect of hindering the segmentation in regions of altered morphology that often occur in diseased retinas. The proposed segmentation method takes into account the presence of lesion related with AMD, i.e., drusen and geographic atrophies (GAs). For that, it is proposed a segmentation scheme that excludes prior information and regularization that is only valid for healthy regions. Even with this segmentation scheme, the prior information and regularization can still cause the oversmoothing of some drusen. To address this problem, it is also proposed the integration of local shape priors in the form of a sparse high order potentials (SHOPs) into the multiple surface framework. Drusen are commonly detected by thresholding the distance among the boundaries that limit drusen. This approach misses drusen or portions of drusen with a height below the threshold. To improve the detection of drusen, Dufour et al. [1] proposed a classification method that detects drusen using textural information. In this work, the method of Dufour et al. [1] is extended by adding new features and performing multi-label classification, which allow the individual detection of drusen when these occur in clusters. Furthermore, local information is incorporated into the classification by combining the classifier with a hidden Markov model (HMM). Both the segmentation and detections methods were evaluated in a database of patients with intermediate AMD. The results suggest that both methods frequently perform better than some methods present in the literature. Furthermore, the results of these two methods form drusen delimitations that are closer to expert delimitations than two methods of the literature.A degenerescência macular relacionada com a idade (DMRI) começa a manifestar-se com o aparecimento de drusas. Progressivamente, as drusas aumentam em tamanho e em número sem causar alterações à visão. Porém, a sua quantificação é importante porque está correlacionada com a evolução da doença para um estado avançado, levar à perda de visão central. A quantificação manual de drusas é impraticável, já que é demorada e requer conhecimento especializado. Por isso, neste trabalho é proposto um método para segmentar drusas automaticamente. Neste trabalho, é proposto um método para segmentar as fronteiras que limitam as drusas e outro método para as localizar através de classificação. O método de segmentação é baseado numa ”framework” de múltiplas superfícies que é adaptada para segmentar as fronteiras que limitam as drusas: a fronteira interior do epitélio pigmentar + complexo de drusas e a membrana de Bruch. Vários métodos de segmentação foram consideravelmente bem-sucedidos a segmentar camadas de retinas saudáveis em imagens de tomografia de coerência ótica. Estes métodos foram bem-sucedidos porque incorporaram informação prévia e regularização. Contudo, estes fatores têm como efeito secundário dificultar a segmentação em regiões onde a morfologia da retina está alterada devido a doenças. O método de segmentação proposto toma em consideração a presença de lesões relacionadas com DMRI, .i.e., drusas e atrofia geográficas. Para isso, é proposto um esquema de segmentação que exclui informação prévia e regularização que são válidas apenas em regiões saudáveis da retina. Mesmo com este esquema de segmentação, a informação prévia e a regularização podem causar a suavização excessiva de algumas drusas. Para tentar resolver este problema, também é proposta a integração de informação prévia local sob a forma de potenciais esparsos de ordem elevada na ”framework” multi-superfície. As drusas são usalmente detetadas por ”thresholding” da distância entre as fronteiras que limitam as drusas. Esta abordagem falha drusas ou porções de drusas abaixo do ”threshold”. Para melhorar a deteção de drusas, Dufour et al. [1] propuseram um método de classificação que deteta drusas usando informação de texturas. Neste trabalho, o método de Dufour et al. [1] é estendido, adicionando novas características e realizando uma classificação com múltiplas classes, o que permite a deteção individual de drusas em aglomerados. Além disso, é incorporada informação local na classificação, combinando o classificador com um modelo oculto de Markov. Ambos os métodos de segmentação e deteção foram avaliados numa base de dados de pacientes com DMRI intermédia. Os resultados sugerem que ambos os métodos obtêm frequentemente melhores resultados que alguns métodos descritos na literatura. Para além disso, os resultados destes dois métodos formam delimitações de drusas que estão mais próximas das delimitações dos especialistas que dois métodos da literatura.This work was supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941. Furthermore, the Portuguese funding institution Fundação Calouste Gulbenkian has conceded me a Ph.D. grant for this work. For that, I wish to acknowledge this institution. Additionally, I want to thank one of its members, Teresa Burnay, for all her assistance with issues related with the grant, for believing that my work was worth supporting and for encouraging me to apply for the grant

Designing and evaluating avatar biosignal visualization techniques in social virtual reality

Social VR is the application of virtual reality that supports remote social interaction in virtual spaces. Users communicate and interact with others in the social VR environment through avatars, which are virtual anthropomorphic characters that aim to represent humans in virtual worlds. In addition, the development of the HMD and commercially available motion capture systems enable the avatars in the virtual environment to detect and reflect the real-time motions, even facial expressions of people. However, the avatars still lack an indication of biofeedback - e.g., body temperature, breathing, heart rate, muscle contraction -, which serves as social cues for communication in reality. While some features, for example, emojis, supports users to express their feeling or emotions for richer communication, the missing information often results in miscommunication in the virtual space. It remains a barrier to a fully immersed experience in the social VR space. This project proposes a concept of visualizing biosignals of the avatars in the social virtual reality space for a richer-level interaction in virtual reality. With the technologies available to capture and reflect accurate biofeedback in real-time, we would like to explore ways and possibilities to map the bio states of the users in reality to avatars in the virtual world. The project starts with conducting user researches to understand the current user behaviors in the social VR spaces and their perspectives on sharing biosignals. Based on the requirements gathered from the user study, the scope of the project is narrowed down to a ‘watching entertainment’ scenario, and the ways to visualize biosignals on avatars were explored through a co-design session with designers. After that, four biosignal visualization techniques in two biosignals - heart rate and breathing rate - are prototyped under the VR jazz bar setting. Finally, the user study is conducted with 16 pairs (32 participants in total) to test and compare the effects of each biosignal visualization technique in watching entertainment scenarios with a companion. As a result, the embodied visualizations are the most understandable and least distracting visualization method among the four methods. Furthermore, the limitations of the research, recommendations on biosignal visualizations, and recommendations on conducting design research are provided

Plurifaceted proteomics in studying cellular dynamics and action mechanisms of anticancer drugs

Mass spectrometry (MS)-based proteomics has developed tremendously in recent years and was the leading technology for many novel methods to study protein chemistry. Contrary to classical approaches based on Western blot, MS-based approaches are mostly unbiased. In addition to protein expression levels, today several protein chemical properties can be examined by MS-based proteomics making it unique in comparison to transcriptomics approaches. These properties include post-translational modifications (PTMs), protein localization, synthesis/degradation, and lastly protein thermal stability, adding novel dimensions or facets to characterize the proteome. However, these facets are difficult to combine as they are mainly orthogonal and are therefore often analyzed separately. This thesis presents a simplified and higher throughput version of current protein stability analyses and showcases the advantages of combined/merged analysis of proteomics facets including our new method, as well as expression and redox proteomics to study anticancer treatments and cellular dynamics. In paper I, we studied the dynamics of cancer cells in vitro with and without anticancer treatment over the course of 48 h by monitoring protein expression every 6 h. We discovered that naturally occurring proteome variations are on par with anticancer treatment killing 50% of the cells after 48 h. Then, we acquired a deep proteomics dataset of untreated HCT116 and A375 cell lines. Surprisingly, we observed downregulation of proteins involved in cell division and upregulation of proteins involved in metabolism as early as 12 h after treatment, suggesting that growth inhibition happens earlier than usually assumed and even at low cell confluence. In paper II we developed the proteome integral solubility alteration (PISA) assay that increases the throughput of pre-existing drug target deconvolution methods based on protein stability/solubility measurements and reduces the analysis time and cost as well as sample requirements. We provided theoretical calculations showing that the integral of the curve correlates well with melting temperature estimations in Thermal Proteome Profiling (TPP) and tested our assumptions with publicly available TPP datasets. Then we performed a proof of principle experiment using the well-studied methotrexate (MTX) and 5-fluorouracile (5-FU) as test drugs highlighting the targets as outliers with our method. Furthermore, we demonstrated that PISA assay can also be used for concentration series analysis as in 2D-TPP. Finally, we showcased the higher throughput of PISA compared to TPP by simultaneously analyzing nine drugs in one multiplexed analysis. In paper III we used a combination of chemical proteomics approaches to study the target and mechanism of action (MOA) of Auranofin (AF) (Ridaura®). Functional Identification of Target by Expression Proteomics (FITExP), TPP, and redox proteomics combined highlighted that thioredoxin reductase 1 (TXNRD1) is indeed a top target hit of AF, and that the main MOA of the drug is through disruption of the redox balance in the cell. Finally, we showed that protein thermal shifts can be associated with altered cysteine oxidation levels in proteins, suggesting that TPP is suitable to study disulfide bond formation/reduction and map some cysteines to the active sites of sulfiredoxin 1 (SRXN1) and peroxiredoxin 5 (PRDX5) as examples. Overall, our study demonstrates that using only one of the proteomics methods is not sufficient to accurately pinpoint drug target and MOA, but a combination of multiple complementary methods should be used instead. Following the success of our strategy in paper III, we decided to utilize the same strategy in paper IV using PISA developed in paper II instead of TPP, to study two novel inhibitors of TXNRD1, namely TRi-1 and TRi-2. For these studies, we used the mouse cancer cell lines B16-F10 and Lewis lung carcinoma (LLC) to provide a comprehensive analysis of the therapeutic effects of the inhibitors. Since we showed that Txnrd1 (the mouse version of the human TXNRD1 protein) is a main target of AF, we decided to use it as our reference point to evaluate the specificity of the two new compounds. AF had a broader effect on the proteome than TRi-1 and TRi-2 and had more target hits in PISA analyses. This suggested that AF has lower specificity than TRi-1 and TRi-2. TRi-1 was the most specific Txnrd1 inhibitor with a better target ranking in FITExP and the least target hits in PISA followed by TRi-2 and AF. Thus, we showed that TRi-1 and TRi-2 are indeed more specific inhibitors of Txnrd1. In addition to these findings, we also highlighted that only AF triggers a high nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant response, suggesting that this response is not necessarily Txnrd1-dependent. Finally, we detected selenocysteine-specific elongation factor (Eefsec), mini-chromosome maintenance complex-binding protein (Mcmbp), glycogen synthase kinase-3 (Gsk3) a and b, as target hits of AF, which would explain at least partially three different effects of AF treatment. Collectively, our data represents a resource for redox biologists interested in Txnrd1 inhibition. Our approach provides a framework for target deconvolution using proteomics approaches. Finally, in paper V we studied the dynamics of the proteome in transition between various cell types. We reprogrammed human foreskin fibroblasts (hFF) into induced pluripotent stem cells (iPSCs), which we differentiated through embryoid bodies (EBs) formation. We examined protein expression and stability after each cell type transition using PISA-Express, a new version of the PISA assay developed in paper II. We merged the readout from protein expression and thermal stability in one analysis using Sankey diagrams to detect changes in protein properties during proteome transitions resulting in the ProteoTracker web interface (http://www.proteotracker.genexplain.com/). Using this innovative analysis, we discovered that ribosomes are less stable in pluripotent stem cells (PSCs) compared to differentiated cells and that this difference stems from the deficiency of one ribosome maturation factor, Shwachman-Bodian-Diamond syndrome protein (SBDS). Knock-down (KD) of SBDS slowed down translation and increased expression of the master pluripotency markers homeobox protein NANOG (NANOG), and octamer-binding transcription factor 4 (OCT4). Collectively, we developed a new method for simultaneous analysis of protein thermal stability and expression, a new analysis and visualization tool, and provided evidence that control of translation through ribosome biogenesis is a natural mechanism used by PSCs to maintain the pluripotency state

Augmented Reality

Augmented Reality (AR) is a natural development from virtual reality (VR), which was developed several decades earlier. AR complements VR in many ways. Due to the advantages of the user being able to see both the real and virtual objects simultaneously, AR is far more intuitive, but it's not completely detached from human factors and other restrictions. AR doesn't consume as much time and effort in the applications because it's not required to construct the entire virtual scene and the environment. In this book, several new and emerging application areas of AR are presented and divided into three sections. The first section contains applications in outdoor and mobile AR, such as construction, restoration, security and surveillance. The second section deals with AR in medical, biological, and human bodies. The third and final section contains a number of new and useful applications in daily living and learning

With renewables for energy security

Taking into account the possible future exhaustion of fossil energy sources, the actual and near danger of climate change, the drastic increase of the greenhouse gases in the last 200 years, as well as the growing need for sustainable development, consumption and liveable environment, the increasing necessity of renewable energy sources becomes clear. Utilization of these energy sources have to acquire a bigger role in the field of energy supply, in order to enhance the energy security of Hungary, to decline the energy import dependence, to reduce the negative environmental impacts, and to recover the economy. The world’s hunger for energy is growing exponentially; this is why it is crucial to establish feasibility scenarios in the next decades, which are able to meet these expectations, and to increase the safety of the energy supply

IMAGING AND BIOLOGICAL MARKERS IN RETINAL DISORDERS TO ASSESS GENE THERAPY SAFETY AND INVESTIGATE VASCULAR DISEASE MECHANISMS

The retina is the neurosensory tissue responsible for the acquisition of visual stimuli. It is biologically separated from the systemic circulation by blood-retinal barriers, limiting the possibility for circulating markers to reflect retinal changes due to disease or therapeutic intervention. However, due to the transparency of ocular media, the retina is highly accessible to high-resolution imaging, and image processing provides access to physiological parameters quantitatively. In addition, the analysis of ocular media sampled during surgical procedures provides access to biological data regarding disease processes. In this work, imaging and biological markers were developed for several experimental and clinical situations: a gene therapy preclinical safety study (Project 1); the analysis of disease mechanisms in the choroical choroidal vascular disorder central serous chorioretinopathy (CSCR) (Project 2), and a similar translational approach in retinal vascular telangiectatic disorders (Project 3). Specific image processing algorithms were designed. In Project 1, the preclinical safety of a lentiviral subretinal gene therapy for RPE65 replacement in Leber congenital amaurosis, LV-RPE65, was assessed on healthy non-human primates by conventional methods (in vivo electrophysiology, ex vivo immunohistochemistry, systemic biodistribution study) combined to in vivo analysis of the retinal structure by optical coherence tomography (OCT) at different timepoints, including early follow-up within 7 days. Imaging techniques revealed a transient and pronounced inflammatory process linked to LV-RPE65 injection that delayed retinal reattachment. Partial and transient photoreceptor loss was observed in the macular region, that was to a lesser extent also observed in control eyes injected with the vehicle. This work highlights the need to improve the surgical procedure for subretinal gene therapy delivery, and to consider using anti-inflammatory agents to prevent damaging processes occurring rapidly after subretinal injection. In Project 2, mechanisms of CSCR, a retinal disease caused by choroidal vessel dilation leading to subretinal fluid accumulation, were explored. We analyzed predictive multimodal imaging factors of episode duration (2a) and recurrence (2b), evidencing in particular choroidal thickness as prognosis factor. Non-invasive OCT angiography images of the choriocapillaris, the innermost layer of the choroid beneath the retinal pigment epithelium, were processed to detect flow voids and investigate their distribution (2c). Finally, the molecular composition of subretinal fluid from a unique case of CSCR requiring subretinal surgery, was explored using a multi-omics approach (2d). In Project 3, mechanisms of retinal vasculopathy were investigated in two pure phenotypes represented by telangiectatic disorders: type 1 macular telangiectasia (Mactel 1) (3a and 3b), and radiation maculopathy (3c). For the investigation of Mactel 1, image processing tools were used to compute global and local capillary density on OCT angiography images, showing that non-perfusion is a critical feature in Mactel 1, related to visual outcome and telangiectasia formation. This approach was combined to the biological investigation of aqueous humor from Mactel 1 cases. Intraocular levels of angiogenic factors demonstrated the involvement of placental growth factor in the pathophysiology of MacTel 1, that was correlated with multimodal imaging findings (3b). Finally, an image processing algorithm was designed and applied to radiation maculopathy, to compute automatically the fractal dimension of OCT angiography images. This parameter was relevant in assessing capillary network disruption, and demonstrated that alterations of the deep plexus influence independently visual function. The strategies developed throughout these three projects demonstrate the interest of quantitative image analysis for the investigation of retinal disorders, and the possibility of coupling imaging and biological data. This approach contributed to identify potential imaging or biological markers for diagnosis, prognosis, therapeutic response and toxicity in several biomedical situations. -- La rétine est un tissu neurosensoriel responsable de l'acquisition des signaux visuels. Elle se trouve biologiquement séparée de la circulation systémique par les barrières hémato-rétiniennes, limitant la possibilité pour des marqueurs circulants de refléter des altérations du tissu rétinien, dus à des maladies ou secondaires à des interventions thérapeutiques. Cependant, en raison de la transparence des milieux oculaires, la rétine est accessible à l'imagerie haute résolution, et l’analyse d'images permet d’extraire des paramètres physiologiques quantitatifs. En outre, l'analyse des milieux oculaires prélevés au cours d’interventions chirurgicales permet d'accéder à des données biologiques concernant les processus physiopathologiques. Dans ce travail, des marqueurs biologiques et d'imagerie ont été développés pour plusieurs situations expérimentales et cliniques : une étude de sécurité préclinique en thérapie génique (Projet 1), l'analyse de mécanismes pathologiques dans la choriorétinopathie séreuse centrale (CRSC) (Projet 2), et dans les pathologies télangiectatiques vasculaires rétiniennes (Projet 3). Des algorithmes de traitement d'image spécifiques ont été conçus. Dans le Projet 1, la tolérance préclinique d'une thérapie génique sous-rétinienne lentivirale pour remplacement du gène RPE65 dans l'amaurose congénitale de Leber, LV-RPE65, a été évaluée sur des primates non humains sains par des méthodes conventionnelles (électrophysiologie in vivo, immunohistochimie ex vivo, étude de biodistribution systémique), et par analyse in vivo de la structure rétinienne par tomographie par cohérence optique (OCT) à différents points, y compris un suivi précoce dans les 7 jours. Les techniques d'imagerie ont révélé un processus inflammatoire transitoire lié à l'injection de LV-RPE65 qui a retardé le réattachement rétinien. Une perte partielle et transitoire des photorécepteurs a été observée dans la région maculaire, détécté également, et dans une moindre mesure dans les yeux témoins, injectés avec la solution véhicule. Ce travail souligne la nécessité d'améliorer la procédure chirurgicale pour l’administration de thérapies géniques sous- rétiniennes, et d'envisager l’usage d’agents anti-inflammatoires pour limiter ces altérations. Dans le projet 2, les mécanismes de la CRSC, une maladie rétinienne causée par la dilatation des vaisseaux choroïdiens menant à l'accumulation de liquide sous-rétinien, ont été explorés. Nous avons analysé les facteurs d'imagerie multimodaux prédictifs de la durée des épisodes (2a) et de récurrence (2b), mettant en évidence notamment l'épaisseur choroïdienne comme facteur pronostic. Des images en OCT angiographie, non invasive, de la choriocapillaire, la couche la plus interne de la choroïde sous l'épithélium pigmentaire rétinien, ont été traitées pour détecter des lacunes dans le flux sanguin, et étudier leur distribution (2c). Enfin, la composition moléculaire du liquide sous-rétinien d'un cas rare de CRSC nécessitant une chirurgie sous-rétinienne, a été explorée en utilisant une approche multi- omique collaborative (2d). Dans le projet 3, les mécanismes de vasculopathie rétinienne ont été étudiés dans deux phénotypes purs représentés par les troubles télangiectasiques : télangiectasie maculaire de type 1 (Mactel 1) (3a et 3b), et maculopathie radique (3c). Pour l'étude de Mactel 1, des outils de traitement d'images ont été utilisés pour calculer la densité capillaire globale et locale sur des images d’OCT angiographie, montrant que la non-perfusion est un paramètre critique dans les Mactel 1, corrélé à la fonction visuelle et à la formation des télangiectasies. Cette approche a été combinée à l'étude biologique de l'humeur aqueuse dans des cas de Mactel 1. Des niveaux intraoculaires de facteurs angiogéniques ont démontré l'implication du facteur de croissance placentaire dans la physiopathologie de MacTel1. De plus, ce facteur était corrélé avec la densité capillaire en OCT angiographie (3b). Enfin, un algorithme de traitement d'images a été conçu et appliqué à la maculopathie radique pour calculer automatiquement la dimension fractale des images d’OCT angiographie. Ce paramètre était pertinent dans l'évaluation de la perturbation du réseau capillaire, et a démontré que les altérations du plexus profond influencent indépendamment la fonction visuelle. Les stratégies développées dans ce travail démontrent l'intérêt de l'analyse d'image quantitative pour l'étude des pathologies rétiniennes, et la possibilité de coupler l'imagerie et les données biologiques. Cette approche a permis d'identifier des marqueurs biologiques ou d'imagerie potentiels pour le diagnostic, le pronostic, la réponse thérapeutique et la toxicité dans les différentes situations étudiées