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    1. Altered ocular microvasculature in patients with systemic sclerosis and very early disease of systemic sclerosis using optical coherence tomography angiography

      Altered ocular microvasculature in patients with systemic sclerosis and very early disease of systemic sclerosis using optical coherence tomography angiography

      The vascular hypothesis of systemic sclerosis (SSc) would predict microvascular alterations should also affect anatomical regions like ocular microvasculature. The objective of this study was to evaluate retinal and choriocapillary vessel density (VD) in patients with definite SSc and very early disease of systemic sclerosis (VEDOSS) using optical coherence tomography angiography (OCTA). 22 eyes of 22 patients and 22 eyes of 22 healthy subjects were included in this study. Patients were classified into patients with definite SSc and patients with VEDOSS. VD data of the superficial OCT angiogram (OCTA-SCP), deep OCT angiogram (OCTA-DCP) and choriocapillaris (OCTA-CC) were analysed. VD in ...

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      Mentions: Visionix
    2. Measuring collagen injury depth for burn severity determination using polarization sensitive optical coherence tomography

      Measuring collagen injury depth for burn severity determination using polarization sensitive optical coherence tomography

      Determining the optimal treatment course for a dermatologic burn wound requires knowledge of the wound's severity, as quantified by the depth of thermal damage. In current clinical practice, burn depth is inferred based exclusively on superficial visual assessment, a method which is subject to substantial error rates in the classification of partial thickness (second degree) burns. Here, we present methods for direct, quantitative determination of the depth extent of injury to the dermal collagen matrix using polarization-sensitive optical coherence tomography (PS-OCT). By visualizing the depth-dependence of the degree of polarization of light in the tissue, rather than cumulative retardation ...

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    3. Subretinal drusenoid deposits as a biomarker of age-related macular degeneration progression via reduction of the choroidal vascularity index

      Subretinal drusenoid deposits as a biomarker of age-related macular degeneration progression via reduction of the choroidal vascularity index

      Background/Objectives This study aimed to analyse the role of the choroid in early age-related macular degeneration (AMD) by analysing choroidal vascularity index (CVI) in pure cohorts of patients with subretinal drusenoid deposits (SDD) or conventional drusen (CD). Subjects/Methods This was an observational cross-sectional study. Comprehensive ophthalmologic examination and multimodal imaging including fundus photography, autofluorescence, near infrared reflectance, and spectral domain optical coherence tomography (SDOCT) was performed. CVI processing was performed on a foveal horizontal SDOCT scan with binarization using Image J Image software and calculated as the ratio between luminal area (LA) and total area (TA). Results Sixty-nine ...

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    4. Light-sheet photonic force optical coherence elastography for high-throughput quantitative 3D micromechanical imaging

      Light-sheet photonic force optical coherence elastography for high-throughput quantitative 3D micromechanical imaging

      Quantitative characterisation of micro-scale mechanical properties of the extracellular matrix (ECM) and dynamic cell-ECM interactions can significantly enhance fundamental discoveries and their translational potential in the rapidly growing field of mechanobiology. However, quantitative 3D imaging of ECM mechanics with cellular-scale resolution and dynamic monitoring of cell-mediated changes to pericellular viscoelasticity remain a challenge for existing mechanical characterisation methods. Here, we present light-sheet photonic force optical coherence elastography (LS-pfOCE) to address this need by leveraging a light-sheet for parallelised, non-invasive, and localised mechanical loading. We demonstrate the capabilities of LS-pfOCE by imaging the micromechanical heterogeneity of fibrous collagen matrices and perform ...

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    5. Asymmetry between right and left optical coherence tomography images identified using convolutional neural networks

      Asymmetry between right and left optical coherence tomography images identified using convolutional neural networks

      In a previous study, we identified biocular asymmetries in fundus photographs, and macula was discriminative area to distinguish left and right fundus images with > 99.9% accuracy. The purposes of this study were to investigate whether optical coherence tomography (OCT) images of the left and right eyes could be discriminated by convolutional neural networks (CNNs) and to support the previous result. We used a total of 129,546 OCT images. CNNs identified right and left horizontal images with high accuracy (99.50%). Even after flipping the left images, all of the CNNs were capable of discriminating them (DenseNet121: 90.33 ...

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    6. Neuroimaging and cognitive correlates of retinal Optical Coherence Tomography (OCT) measures at late middle age in a twin sample

      Neuroimaging and cognitive correlates of retinal Optical Coherence Tomography (OCT) measures at late middle age in a twin sample

      Sharing in embryology and function between the eye and brain has led to interest in whether assessments of the eye reflect brain changes seen in neurodegeneration. We aimed to examine the associations between measures of retinal layer thickness using optical coherence tomography (OCT) and multimodal measures of brain structure and function. Using a convenient sample of twins discordant for type 2 diabetes, we performed cognitive testing, structural brain MRI (tissue volumetry), diffusion tensor imaging (white matter microstructure), and arterial spin labelling (cerebral blood flow). OCT images were recorded and retinal thickness maps generated. We used mixed level modelling to examine ...

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    7. Dynamic full-field optical coherence tomography allows live imaging of retinal pigment epithelium stress model

      Dynamic full-field optical coherence tomography allows live imaging of retinal pigment epithelium stress model

      Retinal degenerative diseases lead to the blindness of millions of people around the world. In case of age-related macular degeneration (AMD), the atrophy of retinal pigment epithelium (RPE) precedes neural dystrophy. But as crucial as understanding both healthy and pathological RPE cell physiology is for those diseases, no current technique allows subcellular in vivo or in vitro live observation of this critical cell layer. To fill this gap, we propose dynamic full-field OCT (D-FFOCT) as a candidate for live observation of in vitro RPE phenotype. In this way, we monitored primary porcine and human stem cell-derived RPE cells in stress ...

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    8. Multi-modal and multi-scale clinical retinal imaging system with pupil and retinal tracking

      Multi-modal and multi-scale clinical retinal imaging system with pupil and retinal tracking

      We present a compact multi-modal and multi-scale retinal imaging instrument with an angiographic functional extension for clinical use. The system integrates scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT) and OCT angiography (OCTA) imaging modalities and provides multi-scale fields of view. For high resolution, and high lateral resolution in particular, cellular imaging correction of aberrations by adaptive optics (AO) is employed. The entire instrument has a compact design and the scanning head is mounted on motorized translation stages that enable 3D self-alignment with respect to the subject’s eye by tracking the pupil position. Retinal tracking, based on the information ...

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    9. Multiplexed spatially-focused localization of light in adipose biological tissues

      Multiplexed spatially-focused localization of light in adipose biological tissues

      Last decades the effects of localization and focusing of light in turbid randomly inhomogeneous tissue-like scattering medium have been attracting a particular attention. Weak localization of light in disordered and weakly ordered biological tissue, polarization memory effect, correlations in transmission matrices, focusing light by wavefronts shaping have been widely exploited. Here, we represent an experimentally observed and theoretically confirmed new type of spatial localization of light within biological tissues. General description of the observed phenomenon based on Monte Carlo ray tracing model is provided. We find that innate body arrangements of individual adipocytes can act as a cascade of quasi-ordered ...

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    10. Predicting persistent central serous chorioretinopathy using multiple optical coherence tomographic images by deep learning

      Predicting persistent central serous chorioretinopathy using multiple optical coherence tomographic images by deep learning

      We sought to predict whether central serous chorioretinopathy (CSC) will persist after 6 months using multiple optical coherence tomography (OCT) images by deep convolutional neural network (CNN). This was a multicenter, retrospective, cohort study. Multiple OCT images, including B-scan and en face images of retinal thickness (RT), mid-retina, ellipsoid zone (EZ) layer, and choroidal layer, were collected from 832 eyes of 832 CSC patients (593 self-resolving and 239 persistent). Each image set and concatenated set were divided into training (70%), validation (15%), and test (15%) sets. Training and validation were performed using ResNet50 CNN architecture for predicting CSC requiring treatment ...

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    11. Changes in circumpapillary retinal nerve fiber layer thickness after vitrectomy for rhegmatogenous retinal detachment

      Changes in circumpapillary retinal nerve fiber layer thickness after vitrectomy for rhegmatogenous retinal detachment

      The study aimed to evaluate the long-term changes in circumpapillary retinal nerve fiber layer (RNFL) thickness after vitrectomy for rhegmatogenous retinal detachment (RRD) repair. A total of 33 eyes of 33 patients were enrolled. By using optical coherence tomography, the circumpapillary RNFL thickness was measured before surgery and 1, 3, 6 months and 1, 2, 3 years after surgery and compared with the preoperative value. The effect of duration, location, and extent of RRD on RNFL thickness change was evaluated. There was a significant increase of circumpapillary RNFL thickness at the 1-month, 3-month [except in the nasal superior sector ( P ...

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    12. Structural retinal changes in cerebral small vessel disease

      Structural retinal changes in cerebral small vessel disease

      Cerebral small vessel disease (CSVD) is an important contributor to cognitive impairment and stroke. Previous research has suggested associations with alterations in single retinal layers. We have assessed changes of all individual retinal layers in CSVD using high-resolution optical coherence tomography (OCT) for the first time. Subjects with recent magnetic resonance imaging (MRI) underwent macular and peripapillary retinal imaging using OCT for this case–control study. Number and volume ratio index (WMRI) of white matter lesions (WML) were determined on MRI. Data were analyzed using multiple linear regression models. 27 CSVD patients and 9 control participants were included. Ganglion cell ...

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    13. Epidural anesthesia needle guidance by forward-view endoscopic optical coherence tomography and deep learning

      Epidural anesthesia needle guidance by forward-view endoscopic optical coherence tomography and deep learning

      Epidural anesthesia requires injection of anesthetic into the epidural space in the spine. Accurate placement of the epidural needle is a major challenge. To address this, we developed a forward-view endoscopic optical coherence tomography (OCT) system for real-time imaging of the tissue in front of the needle tip during the puncture. We tested this OCT system in porcine backbones and developed a set of deep learning models to automatically process the imaging data for needle localization. A series of binary classification models were developed to recognize the five layers of the backbone, including fat, interspinous ligament, ligamentum flavum, epidural space ...

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    14. Ability of Swept-source OCT and OCT-angiography to detect neuroretinal and vasculature changes in patients with Parkinson disease and essential tremor

      Ability of Swept-source OCT and OCT-angiography to detect neuroretinal and vasculature changes in patients with Parkinson disease and essential tremor

      Background/Objectives To evaluate the ability of swept-source optical coherence tomography (SS-OCT) implemented with angiography analysis (SS-OCTA) to detect neuro-retinal and vasculature changes in patients with Parkinson’s disease (PD) and essential tremor (ET), and to distinguish between both pathologies. Subjects/Methods A total 42 PD and 26 ET patients and 146 controls underwent retinal evaluation using SS-OCT plus OCT-Angio™. The macular (m) and peripapillary (p) retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL), and macular vasculature were assessed. A Linear discriminant function (LDF) was calculated to evaluate the diagnostic ability of SS-OCTA in both PD and ET ...

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    15. Glaucoma diagnosis using multi-feature analysis and a deep learning technique

      Glaucoma diagnosis using multi-feature analysis and a deep learning technique

      In this study, we aimed to facilitate the current diagnostic assessment of glaucoma by analyzing multiple features and introducing a new cross-sectional optic nerve head (ONH) feature from optical coherence tomography (OCT) images. The data (n = 100 for both glaucoma and control) were collected based on structural, functional, demographic and risk factors. The features were statistically analyzed, and the most significant four features were used to train machine learning (ML) algorithms. Two ML algorithms: deep learning (DL) and logistic regression (LR) were compared in terms of the classification accuracy for automated glaucoma detection. The performance of the ML models was ...

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    16. Longitudinal in-vivo quantification of tumour microvasculature heterogeneity via optical coherence tomography (OCT) angiography in a pre-clinical model of radiation therapy

      Longitudinal in-vivo quantification of tumour microvasculature heterogeneity via optical coherence tomography (OCT) angiography in a pre-clinical model of radiation therapy

      Stereotactic body radiotherapy (SBRT) is an emerging cancer treatment due to its logistical and potential therapeutic benefits as compared to conventional radiotherapy. However, its mechanism of action is yet to be fully understood, likely involving the ablation of tumour microvasculature by higher doses per fraction used in SBRT. In this study, we hypothesized that longitudinal imaging and quantification of the vascular architecture may elucidate the relationship between the microvasculature and tumour response kinetics. Pancreatic human tumour xenografts were thus irradiated with single doses of 10 10 , 20 20 and 30 30 Gy to simulate the first fraction of a SBRT ...

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    17. Visual outcomes and predictors in optic pathway glioma: a single centre study

      Visual outcomes and predictors in optic pathway glioma: a single centre study

      Background/Aims Optic pathway gliomas (OPGs) may cause progressive visual loss despite chemotherapy. Newer, less toxic treatments might be given earlier, depending on visual prognosis. We aimed to investigate the prognostic value of visual evoked potentials (VEP) and optical coherence tomography (OCT). Methods A retrospective study of OPG patients (treated 2003–2017) was conducted. Primary outcome was PEDIG category visual acuity in better and worse eyes (good < = 0.2, moderate 0.3–0.6 and poor > = 0.7 logMAR). Binary logistic regression analysis was used to identify predictors of these outcomes. Results 60 patients (32 Neurofibromatosis type 1 [NF1] and ...

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    18. Retinal pigment epithelium melanin imaging using polarization-sensitive optical coherence tomography for patients with retinitis pigmentosa

      Retinal pigment epithelium melanin imaging using polarization-sensitive optical coherence tomography for patients with retinitis pigmentosa

      This study aimed to evaluate the distribution of retinal pigment epithelium (RPE) melanin in patients with retinitis pigmentosa (RP) using entropy measurements by custom-made polarization-sensitive optical coherence tomography (PS-OCT) images, and compare entropy with the intensity of short-wavelength (SW) and near-infrared (NIR) autofluorescence (AF). We retrospectively reviewed the retinal images, including PS-OCT, SW-AF, and NIR-AF of patients with RP who had a hyperautofluorescent ring on AF. A total of 12 eyes of 12 patients (8 women and 4 men; mean age: 37.9 years) were included. There was a strong positive correlation between entropy value and NIR-AF intensity (r = 0 ...

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    19. Intravascular polarization-sensitive optical coherence tomography based on polarization mode delay

      Intravascular polarization-sensitive optical coherence tomography based on polarization mode delay

      Intravascular polarization-sensitive optical coherence tomography (IV-PSOCT) provides depth-resolved tissue birefringence which can be used to evaluate the mechanical stability of a plaque. In our previous study, we reported a new strategy to construct polarization-sensitive optical coherence tomography in a microscope platform. Here, we demonstrated that this technology can be implemented in an endoscope platform, which has many clinical applications. A conventional intravascular OCT system can be modified for IV-PSOCT by introducing a 12-m polarization-maintaining fiber-based imaging probe. Its two polarization modes separately produce OCT images of polarization detection channels spatially distinguished by an image separation of 2.7 mm. We ...

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      Mentions: UC Irvine
    20. Optical coherence tomography in coronary atherosclerosis assessment and intervention

      Optical coherence tomography in coronary atherosclerosis assessment and intervention

      Since optical coherence tomography (OCT) was first performed in humans two decades ago, this imaging modality has been widely adopted in research on coronary atherosclerosis and adopted clinically for the optimization of percutaneous coronary intervention. In the past 10 years, substantial advances have been made in the understanding of in vivo vascular biology using OCT. Identification by OCT of culprit plaque pathology could potentially lead to a major shift in the management of patients with acute coronary syndromes. Detection by OCT of healed coronary plaque has been important in our understanding of the mechanisms involved in plaque destabilization and healing ...

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    21. Quantitative analysis of preclinical ocular microvascular changes in Multisystemic Inflammatory Syndrome in Children (MIS-C) detected by optical coherence tomography angiography

      Quantitative analysis of preclinical ocular microvascular changes in Multisystemic Inflammatory Syndrome in Children (MIS-C) detected by optical coherence tomography angiography

      Objectives To evaluate the macular and optic nerve head (ONH) vascular density, foveal avascular zone area, and outer retina and choriocapillaris flow in Multisystemic Inflammatory Syndrome in Children (MIS-C) using optical coherence tomography angiography (OCTA). Methods Thirty-four eyes of 34 patients with MIS-C and 36 age and sex-matched healthy controls were investigated in this prospective, cross-sectional study. The superficial capillary plexus (SCP) and deep capillary plexus (DCP), ONH, FAZ parameters, the flow area of the outer retina, and choriocapillaris were evaluated using OCTA. Results All VD parameters in SCP were significantly lower in MIS-C patients. There was no significant difference ...

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    22. Enhance the delivery of light energy ultra-deep into turbid medium by controlling multiple scattering photons to travel in open channels

      Enhance the delivery of light energy ultra-deep into turbid medium by controlling multiple scattering photons to travel in open channels

      Multiple light scattering is considered as the major limitation for deep imaging and focusing in turbid media. In this paper, we present an innovative method to overcome this limitation and enhance the delivery of light energy ultra-deep into turbid media with significant improvement in focusing. Our method is based on a wide-field reflection matrix optical coherence tomography (RM-OCT). The time-reversal decomposition of the RM is calibrated with the Tikhonov regularization parameter in order to get more accurate reversal results deep inside the scattering sample. We propose a concept named model energy matrix, which provides a direct mapping of light energy ...

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      Mentions: UC Irvine
    23. Optical coherence tomography as retinal imaging biomarker of neuroinflammation/neurodegeneration in systemic disorders in adults and children

      Optical coherence tomography as retinal imaging biomarker of neuroinflammation/neurodegeneration in systemic disorders in adults and children

      The retina and the optic nerve are considered extensions of the central nervous system (CNS) and thus can serve as the window for evaluation of CNS disorders. Spectral domain optical coherence tomography (OCT) allows for detailed evaluation of the retina and the optic nerve. OCT can non-invasively document changes in single retina layer thickness and structure due to neuronal and retinal glial cells (RGC) modifications in systemic and local inflammatory and neurodegenerative diseases. These can include evaluation of retinal nerve fibre layer and ganglion cell complex, hyper-reflective retinal spots (HRS, sign of activated microglial cells in the retina), subfoveal neuroretinal ...

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    24. Video-rate high-precision time-frequency multiplexed 3D coherent ranging

      Video-rate high-precision time-frequency multiplexed 3D coherent ranging

      Frequency-modulated continuous wave (FMCW) light detection and ranging (LiDAR) is an emerging 3D ranging technology that offers high sensitivity and ranging precision. Due to the limited bandwidth of digitizers and the speed limitations of beam steering using mechanical scanners, meter-scale FMCW LiDAR systems typically suffer from a low 3D frame rate, which greatly restricts their applications in real-time imaging of dynamic scenes. In this work, we report a high-speed FMCW based 3D imaging system, combining a grating for beam steering with a compressed time-frequency analysis approach for depth retrieval. We thoroughly investigate the localization accuracy and precision of our system ...

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      Mentions: Thorlabs
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