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    1. Vascular and Structural Alterations of the Choroid Evaluated by Optical Coherence Tomography Angiography and Enhanced-Depth Imaging Optical Coherence Tomography in Eyes with Reticular Pseudodrusen and Soft Drusen

      Vascular and Structural Alterations of the Choroid Evaluated by Optical Coherence Tomography Angiography and Enhanced-Depth Imaging Optical Coherence Tomography in Eyes with Reticular Pseudodrusen and Soft Drusen

      Background To assess the vascularity of choriocapillaris and structural choroidal differences in eyes with reticular pseudodrusen (RPD) and soft drusen. Methods 21 eyes with RPD (group 1), 17 eyes with soft drusen (group 2), and 19 eyes as a control group (group 3) were included in this study. Choriocapillaris vascular density and flow area were measured by optical coherence tomography angiography. Total choroidal area, luminal area, stromal area, and lumen/stroma ratios were measured on optical coherence tomography B-scans converted to binary images. Results Mean choriocapillaris vascular density was higher in group 3 than other groups (group 1 vs 3 ...

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    2. Modular deep neural networks for automatic quality control of retinal optical coherence tomography scans

      Modular deep neural networks for automatic quality control of retinal optical coherence tomography scans

      Retinal optical coherence tomography (OCT) with intraretinal layer segmentation is increasingly used not only in ophthalmology but also for neurological diseases such as multiple sclerosis (MS). Signal quality influences segmentation results, and high-quality OCT images are needed for accurate segmentation and quantification of subtle intraretinal layer changes. Among others, OCT image quality depends on the ability to focus, patient compliance and operator skills. Current criteria for OCT quality define acceptable image quality, but depend on manual rating by experienced graders and are time consuming and subjective. In this paper, we propose and validate a standardized, grader-independent, real-time feedback system for ...

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      Mentions: UC Irvine
    3. Optical Coherence Tomography of Plaque Vulnerability and Rupture: JACC Focus Seminar Part 1/3

      Optical Coherence Tomography of Plaque Vulnerability and Rupture: JACC Focus Seminar Part 1/3

      Plaque rupture is the most common cause of acute coronary syndromes and sudden cardiac death. Characteristics and pathobiology of vulnerable plaques prone to plaque rupture have been studied extensively over 2 decades in humans using optical coherence tomography (OCT), an intravascular imaging technique with micron scale resolution. OCT studies have identified key features of plaque vulnerability and described the in vivo characteristics and spatial distribution of thin cap fibroatheromas as major precursors to plaque rupture. In addition, OCT data supports the evolving understanding of coronary heart disease as a panvascular process associated with inflammation. In the setting of high atherosclerotic ...

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    4. Optical Coherence Tomography of Plaque Erosion: JACC Focus Seminar Part 2/3

      Optical Coherence Tomography of Plaque Erosion: JACC Focus Seminar Part 2/3

      Plaque erosion, a distinct histopathological and clinical entity, accounts for over 30% of acute coronary syndromes (ACS). Optical coherence tomography allows in vivo diagnosis of plaque erosion. Local flow perturbation with activation of Toll-like receptor 2 and CD8 + T cells and subsequent desquamation of endothelium and neutrophil extracellular trap formation contribute to mechanisms of plaque erosion. Compared with ACS patients with plaque rupture, those with plaque erosion are younger, have fewer traditional cardiovascular risk factors, have lower plaque burden, and are more likely to present with non-ST-segment elevation ACS. Early evidence suggests that in patients with ACS caused by plaque ...

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    5. Optical Coherence Tomography of Coronary Plaque Progression and Destabilization: JACC Focus Seminar Part 3/3

      Optical Coherence Tomography of Coronary Plaque Progression and Destabilization: JACC Focus Seminar Part 3/3

      The development of optical coherence tomography (OCT) has revolutionized our understanding of coronary artery disease. In vivo OCT research has paralleled with advances in computational fluid dynamics, providing additional insights in the various hemodynamic factors influencing plaque growth and stability. Recent OCT studies introduced a new concept of plaque healing in relation to clinical presentation. In addition to known mechanisms of acute coronary syndromes such as plaque rupture and plaque erosion, a new classification of calcified plaque was recently reported. This review will focus on important new insights that OCT has provided in recent years into coronary plaque development, progression ...

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    6. Optical coherence tomography angiography features of macular neovascularization in wet age-related macular degeneration: A cross-sectional study

      Optical coherence tomography angiography features of macular neovascularization in wet age-related macular degeneration: A cross-sectional study

      Background OCT-A is a recent imaging technique allowing a non-invasive assessment of the retinal and choroidal microvasculature , providing valuable data for the diagnosis and monitoring of wet AMD . We aim to determine the diagnosis accuracy, describe the morphological features, and assess the clinical activity of MNV in wet AMD using OCT-A. Materials and methods We conducted a descriptive cross-sectional study over a 15-month period. We enrolled patients with treatment-naive and treated MNV secondary to wet AMD. Macular OCT-A images were obtained using a swept-source OCT-A device (Triton SS-OCT, Topcon, Tokyo, Japan). Morphologic characteristics and semi-automated measurements were analyzed on the ...

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    7. A preliminary study of shaker-based optical coherence elastography for assessment of gingival elasticity

      A preliminary study of shaker-based optical coherence elastography for assessment of gingival elasticity

      Studies on the changes in biomechanical properties of the gingiva are significant, since they are closely related to the pathological process of gingivitis and periodontitis. Although some research has been conducted, the currently used techniques are not feasible for in vivo and clinical measurements due to their disadvantages, such as the invasive nature and the requirement of thin sectioning. In this study, we developed a shaker-based optical coherence elastography system which provides noninvasive measurement, high axial resolution, high displacement sensitivity, and real-time imaging, and explored its potential for the detection of gingival elasticity. The system was tested by an agar ...

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    8. Head-to-head comparison of quantitative measurements between intravascular imaging systems: An in vitro phantom study

      Head-to-head comparison of quantitative measurements between intravascular imaging systems: An in vitro phantom study

      Introduction The present study aimed to compare the accuracy of quantitative measurements by contemporary intravascular imaging systems including optical frequency domain imaging (OFDI), frequency domain optical coherence tomography (FD-OCT), and 6 intravascular ultrasound (IVUS) systems. Methods We imaged five cylindrical phantom models made from an acrylic resin with known lumen diameters (1.51, 2.03, 3.04, 4.04, and 5.04 mm, respectively) using OFDI (FastView and LUNAWAVE, Terumo), FD-OCT (Dragonfly JP and ILUMIEN OPTIS, Abbott Vascular), and 6 mechanically rotating IVUS systems including a system, two 40-MHz, one 45-MHz, two 60-Mhz and one broad-band frequency IVUS systems. The ...

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    9. In vivo optical coherence tomography-guided photodynamic therapy for skin pre-cancer and cancer

      In vivo optical coherence tomography-guided photodynamic therapy for skin pre-cancer and cancer

      Background: The primary aim of this prospective study is to demonstrate the technical feasibility of OCT to map real tumor margins and to monitor skin changes that occurred post- PDT. Moreover, to optimize PDT efficacy based on the relationship between measured OCT features and treatment outcome. Material and methods: A series of 12 patients with overall 18 facial skin lesions were investigated by OCT before surface illumination by PDT to determine tumor free margins. Monitoring of the healing process was undertaken at 3, 6 and 12 months post-PDT. Parameters measured by the in vivo OCT during healing phase were the ...

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    10. In vivo imaging of the inner retinal layer structure in mice after eye-opening using visible-light optical coherence tomography

      In vivo imaging of the inner retinal layer structure in mice after eye-opening using visible-light optical coherence tomography

      The growth of the mouse eye and retina after birth is a dynamic, highly regulated process. In this study, we applied visible-light optical coherence tomography (vis-OCT), a non-invasive imaging technique, to examine developing retinal layer structures after eye-opening. We introduced a resampled circumpapillary B-scan averaging technique to improve the inter-layer contrast, enabling retinal layer thickness measurements as early as postnatal day 13 (P13) - right after eye-opening. We confirmed vis-OCT measurements using ex vivo confocal microscopy of retinal sections at different ages. Our results demonstrate that vis-OCT can visualize the developmental murine retinal layer structure in vivo, which offers us new ...

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    11. In situ process monitoring and automated multi-parameter evaluation using optical coherence tomography during extrusion-based bioprinting

      In situ process monitoring and automated multi-parameter evaluation using optical coherence tomography during extrusion-based bioprinting

      In three-dimensional (3D) bioprinting, errors during the printing process leads to lower structural fidelity, and the desired structural and functional performances cannot be fully satisfied. Process monitoring with high-speed imaging techniques is helpful for identifying material deposition errors. 3D reconstruction of printed objects enables comprehensive evaluation of structural characteristics, with wide-field full-depth imaging being necessary for large objects. In this study, we demonstrate 3D extrusion-based bioprinter-associated optical coherence tomography (3D P-OCT) to achieve high-speed, wide-field and full-depth imaging, and provide in situ process monitoring and comprehensive evaluation for 3D bioprinting . In 3D P-OCT, a wide field was achieved with a ...

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    12. Detection of Hard Exudate using Retinal Optical Coherence Tomography (OCT) Images

      Detection of Hard Exudate using Retinal Optical Coherence Tomography (OCT) Images

      To distinguish DR retinal one device is utilized called Optical Coherence Tomography (OCT). So to break down hard exudates (HEs) and their antecedents in patients with diabetic retinopathy (DR) by utilizing Optical Coherence Tomography (OCT) pictures is fundamental. Hard Exudates (HEs) are one kind of principle sign of DR. It is the back shaft of an eye with macular edema. Modified acknowledgment of HE from the retinal picture is a critical development for the area of DR. HE is an essential in the eye for those having diabetes. This Hard Exudates can provoke visual weakness if not managed before all ...

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    13. Operando observation of concentrated SiO2 suspensions by optical coherent tomography during flow curve measurements: The relationship between polymer dispersant structures and surface interactions

      Operando observation of concentrated SiO2 suspensions by optical coherent tomography during flow curve measurements: The relationship between polymer dispersant structures and surface interactions

      Hypothesis Flow curve measurement is commonly used to characterize the flow behavior of concentrated suspensions. However, dynamic changes in the suspension inner microstructures under highly sheared conditions have not been correctly understood even though they strongly affect the measured shear stress. We hypothesize that the real particle dynamics during shearing could be effectively revealed by a systematic investigation that combines macroscopic flow curve measurements with operando microstructural observation employing an optical coherent tomography (OCT) apparatus and surface interaction measurements with the colloidal probe atomic force microscopy (AFM) method. Experiments The model system was spherical SiO 2 /toluene suspensions stabilized by ...

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    14. CDC-Net: Cascaded decoupled convolutional network for lesion-assisted detection and grading of retinopathy using optical coherence tomography (OCT) scans

      CDC-Net: Cascaded decoupled convolutional network for lesion-assisted detection and grading of retinopathy using optical coherence tomography (OCT) scans

      Retinopathy refers to any injury in the retinal region of the eye that can lead to distorted vision or even blindness. The segmentation of retinal lesions or biomarkers is crucial for the precise classification and grading of retinopathy. Optical coherence tomography imaging is the widely used eye examination tool by ophthalmologists due to its comprehensive visualization of the retinal lesions, which can assist in the prompt treatment of retinal conditions. However, due to vast clinical optical coherence tomography applications and the incidence of ocular syndromes, the number of scans collected daily outweighs ophthalmologists’ capacity to interpret these in a meaningful ...

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    15. Polarization Sensitive Optical Coherence Tomography for Bronchoscopic Airway Smooth Muscle Detection in Bronchial Thermoplasty-Treated Patients With Asthma

      Polarization Sensitive Optical Coherence Tomography for Bronchoscopic Airway Smooth Muscle Detection in Bronchial Thermoplasty-Treated Patients With Asthma

      Asthma is a chronic inflammatory disease characterized by airway remodeling (AR), including thickening of airway smooth muscle (ASM) as a key element of this alteration. 1 Patients with severe asthma may benefit from bronchial thermoplasty (BT), an endoscopic treatment that targets structural AR and induces ASM reduction. 2 Assessment of AR is critical to evaluate the impact of BT and might provide a tool for patient selection for BT. Polarization sensitive optical coherence tomography (PS-OCT) imaging has been proposed as a minimally invasive diagnostic method to assess ASM mass as an alternative to focal airway biopsies. Bronchoscopic standard optical coherence ...

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    16. A novel 3D printed hollow microneedle microelectromechanical system for controlled, personalized transdermal drug delivery

      A novel 3D printed hollow microneedle microelectromechanical system for controlled, personalized transdermal drug delivery

      The advancement of drug delivery devices is critical for the individualization of patient treatment and the improvement of healthcare. Here, we introduce the 3DMNMEMS, a novel device that combines 3D printing, microneedles (MNs) and Microelectromechanical Systems (MEMS), allowing versatile and controllable by the user transdermal drug delivery. Hollow MNs were designed and 3D printed using Stereolithography, followed by integrating into a MEMS. By employing advanced imaging techniques, we monitored the distribution of liquid delivered by the device within skin tissue in real time. In vivo testing revealed that the delivery of insulin using the 3DMNMEMS achieved improved glycemic control to ...

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    17. Automated delineation of corneal layers on OCT images using a boundary-guided CNN

      Automated delineation of corneal layers on OCT images using a boundary-guided CNN

      Accurate segmentation of corneal layers depicted on optical coherence tomography (OCT) images is very helpful for quantitatively assessing and diagnosing corneal diseases ( e.g ., keratoconus and dry eye). In this study, we presented a novel boundary-guided convolutional neural network (CNN) architecture (BG-CNN) to simultaneously extract different corneal layers and delineate their boundaries. The developed BG-CNN architecture used three convolutional blocks to construct two network modules on the basis of the classical U-Net network. We trained and validated the network on a dataset consisting of 1,712 OCT images acquired on 121 subjects using a 10-fold cross-validation method. Our experiments showed ...

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    18. In vivo optical coherence tomography in assessment of suspicious facial lesions: A prospective study

      In vivo optical coherence tomography in assessment of suspicious facial lesions: A prospective study

      Background: Skin cancer continues to be the most common cancer in the Caucasian population. Over the past two decades, researchers around the world started assessing the possibility of diagnosing tissue pathologies by using optical systems. In this study, we aimed to use in vivo optical coherence tomography (OCT) technology to describe the morphologic features of normal and pathologic skin conditions. Materials and methods: In this study, 72 patients with suspected skin pre-cancer/cancer were recruited. The lesions were subjected to in vivo OCT scanning using compact size probe. The main scanned areas were the centre of the lesion, periphery of ...

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    19. Circumpapillary OCT-focused hybrid learning for glaucoma grading using tailored prototypical neural networks

      Circumpapillary OCT-focused hybrid learning for glaucoma grading using tailored prototypical neural networks

      Glaucoma is one of the leading causes of blindness worldwide and Optical Coherence Tomography (OCT) is the quintessential imaging technique for its detection. Unlike most of the state-of-the-art studies focused on glaucoma detection, in this paper, we propose, for the first time, a novel framework for glaucoma grading using raw circumpapillary B-scans. In particular, we set out a new OCT-based hybrid network which combines hand-driven and deep learning algorithms. An OCT-specific descriptor is proposed to extract hand-crafted features related to the retinal nerve fibre layer (RNFL). In parallel, an innovative CNN is developed using skip-connections to include tailored residual and ...

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    20. Optical coherence tomography angiography vessel density parameters in primary open-angle glaucoma

      Optical coherence tomography angiography vessel density parameters in primary open-angle glaucoma

      Background: Many studies suggest the existence of an alteration of the retinal hemoperfusion in primary open-angle glaucoma. The OCT-A is a novel technique that allows to provide information on retinal microcirculation in a non-invasive way, thus it represents a possible imaging target for the early diagnosis and follow-up of glaucoma. The aim of our work is to evaluate the contribution of vascular parameters provided by OCT-A and their diagnostic abilities in the different stages of primary open-angle glaucoma. Method: This is a prospective cross-sectional study involving 200 eyes of control subjects and 250 eyes of glaucomatous subjects divided into early ...

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    21. Association of Cigarette Smoking with Retinal Thickness and Vascular Structure in Elderly Chinese Population

      Association of Cigarette Smoking with Retinal Thickness and Vascular Structure in Elderly Chinese Population

      Background: To explore the association of cigarette smoking with retinal thickness and vascular structure in an elderly Chinese population. Methods: This cross-sectional study enrolled employees and retirees aged over 50 years at Tianjin University of Sport from October 2020 to December 2020. Information on smoking status and lifestyle was obtained using a detailed questionnaire. All participants underwent full ophthalmic examination. OCTA image was acquired. Vascular and the thickness parameters in central fovea and peripapillary parameters were automatically calculated. Multiple linear regression analyses were utilized to assess the association of smoking with retinal thickness and vascular structure after controlling potential confounders ...

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    22. Evaluation of Subclinical Alterations in Retinal Layers and Microvascular Structures with OCT and OCTA in Healthy Young Short-term Smokers

      Evaluation of Subclinical Alterations in Retinal Layers and Microvascular Structures with OCT and OCTA in Healthy Young Short-term Smokers

      Purpose: To detect the changes that can be determined with optical coherence tomography(OCT) and optical coherence tomography angiography(OCTA) in young and short-term smokers. Method: In this cross-sectional, observational, and comparative study, 45 healthy smokers and 45 healthy non-smoker control participants were included. Those with a smoking history between 1 year to 5 years and an average of 10-30 cigarettes per day were included in the study. OCT and OCTA measurements were made at least 60 minutes after smoking and at least 8 hours after caffeine-containing beverages in order to end the effect of nicotine on systemic and retinal ...

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