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    1. Quantitative Articular Cartilage Sub-Surface Defect Assessment Using Optical Coherence Tomography: An In-Vitro Study

      Quantitative Articular Cartilage Sub-Surface Defect Assessment Using Optical Coherence Tomography: An In-Vitro Study

      Assessment of structural cartilage damage is of high scientific and clinical interest. Optical Coherence Tomography (OCT) is a light-based cross-sectional imaging modality that allows the real-time assessment of articular cartilage at near-histological resolution. Algorithm routines for the detection, parameterization and quantification of sub-surface defects as assessed by OCT were implemented and validated in this study. Standard defects of 0.9 mm, 1.1 mm and 1.3 mm diameter were created in the sub-surface regions of macroscopically intact human articular cartilage samples (n = 60 defects of variable sizes in n = 20 samples). Subsequently, samples were scanned by 3D OCT and ...

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    2. Changes In Retinal Thickness On Optical Coherence Tomography From Intravitreal Melphalan

      Changes In Retinal Thickness On Optical Coherence Tomography From Intravitreal Melphalan

      PURPOSE To quantify changes in central retinal thickness (CRT) on intraoperative spectral domain optical coherence tomography (SD-OCT) pre- and post- intravitreal melphalan (IVM) injection for retinoblastoma (Rb). METHODS Retrospective review of 5 eyes of 5 patients with Rb without macular tumor involvement treated with IVM injection for vitreous seeding. Automated and manual ETDRS measurements of CRT sub-foveally were derived from SD-OCT images pre- and post- IVM injection. RESULTS Mean age of patients at first IVM was 512 days (range=133-1005). Mean follow-up duration was 266 days (range=21-532). Grade 1, Grade IV, and Grade V chorioretinal toxicity occurred in 2 ...

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    3. Investigation of Puccinia triticina contagion on wheat leaves using swept source optical coherence tomography

      Investigation of Puccinia triticina contagion on wheat leaves using swept source optical coherence tomography

      We present an investigation on applicability of swept-source optical coherence tomography (SSOCT) to examine the internal structures of plant leaves. This study helps to identify the growth and spread of the leaf rust disease in leaves of wheat plants, caused by Puccinia triticina . The epidermal cell layer and parenchyma cell layer of the acquired OCT images are correlated with the histological images to show distinctive leaf morphological boundaries. In the OCT images, the thickness of the parenchyma cell layer in healthy and infected samples are compared and analyzed. Accurate morphological and quantitative information are obtained with our developed system for ...

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      Mentions: Raju Poddar
    4. Optical coherence tomography angiography measured capillary density in normal and glaucoma eyes: RPCs and ONH capillary density in glaucoma

      Optical coherence tomography angiography measured capillary density in normal and glaucoma eyes: RPCs and ONH capillary density in glaucoma

      Purpose To compare the diagnostic ability of optical coherence tomography angiography (OCT-A) derived radial peripapillary capillary (RPC) measured capillary density (CD) and inside the optic nerve head (ONH) CD measurements to differentiate between the normal and primary open angle glaucoma (POAG) eyes. Methods AngioVue disc OCT-A images were obtained and assessed in 83 eyes of POAG patients and 74 age matched healthy eyes. RPC CD was quantitatively measured in the peripapillary area within 3.45 mm circle diameter around the ONH and inside the ONH in 8 equally divided sectors, using Bar – Selective Combination of Shifted Filter Responses method after ...

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    5. Correlation Between Intraocular Pressure and Angle Configuration Measured by Optical Coherence Tomography: The Chinese American Eye Study

      Correlation Between Intraocular Pressure and Angle Configuration Measured by Optical Coherence Tomography: The Chinese American Eye Study

      PURPOSE To characterize the relationship between angle configuration measured by anterior segment optical coherence tomography (AS-OCT) and intraocular pressure (IOP). DESIGN Cross-sectional study. PARTICIPANTS Subjects aged 50 years or older were identified from the Chinese American Eye Study (CHES), a population-based epidemiological study in Los Angeles, CA. METHODS Each subject underwent a complete ocular exam including Goldmann applanation tonometry, gonioscopy, and AS-OCT imaging. Four AS-OCT images were analyzed per eye and parameters describing angle configuration were measured, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), and scleral spur angle (SSA ...

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      Mentions: Rohit Varma UCLA
    6. Zinc oxide nanoparticles (ZnONPs) as contrast agent for imaging of animal tissue using swept source optical coherence tomography (SSOCT)

      Zinc oxide nanoparticles (ZnONPs) as contrast agent for imaging of animal tissue using swept source optical coherence tomography (SSOCT)

      We present applicability of ZnO nanoparticles (ZnONPs) as a potential contrast agent for Optical Coherence Tomography (OCT) imaging. A 1064 nm laser source was used in a swept source configuration capable of a scanning rate of 100 kHz (100,000 A-lines/s). Swept Source Optical Coherence Tomography (SSOCT) is a variation of OCT, offering greater scan rates, higher resolution and signal-to-noise ratios. To enhance the contrast of an OCT frame, ZnO nanoparticles were used as an exogeneous contrast agent, which were fabricated using zinc acetic acid derivation and oxalic acid via precipitation. The particles were characterized using UV–vis Spectroscopy ...

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      Mentions: Raju Poddar
    7. Wide-field swept-source optical coherence tomography and angiography in X-linked retinoschisis

      Wide-field swept-source optical coherence tomography and angiography in X-linked retinoschisis

      Objective Retinal vascular and structural changes, particularly outside of the central macula, are not well characterized in X-linked retinoschisis (XLRS). We aim to describe wide-field swept-source optical coherence tomography (SS-OCT) and angiography (SS-OCTA) findings in XLRS. Design Retrospective, cross-sectional study at a tertiary referral center Participants Nine consecutive male patients with molecularly-confirmed XLRS Methods All patients underwent complete ophthalmic examination with multimodal imaging, including SS-OCT with SS-OCTA (PLEX Elite 9000; Carl-Zeiss Meditec Inc, Dublin, California). Images were then reviewed by two retinal specialists as independent graders to determine the frequency and distribution of retinal structural and vascular abnormalities. Main Outcome ...

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    8. Detection of microvascular retinal changes in type I diabetic mice with optical coherence tomography angiography

      Detection of microvascular retinal changes in type I diabetic mice with optical coherence tomography angiography

      Optical coherence tomography (OCT) angiography is a dye-free and non-invasive angiography which allows visualization of retinal and choroid vascular flow, enabling observation of highly permeable and three dimensional vasculature. Although OCT angiography is providing new insights in human retinal and choroidal diseases, a few studies have been reported in experimental mice. In this study, to determine the potential of OCT angiography in experimental mice, we sought to examine whether OCT angiography can detect vascular change in type I diabetic mice. To conduct age dependent analysis, 2 and 6 month old male type 1 diabetic Ins2 Akita/+ and age matched C57BL ...

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    9. En Face Imaging of Geographic Atrophy Using Different Swept-Source Optical Coherence Tomography Scan Patterns

      En Face Imaging of Geographic Atrophy Using Different Swept-Source Optical Coherence Tomography Scan Patterns

      Purpose Different swept source optical coherence tomography (SS-OCT) scan patterns were used to image geographic atrophy (GA) to determine if they provided similar area and enlargement measurements in eyes with age-related macular degeneration (AMD). Design Prospective, observational case series. Participants Patients with GA secondary to non-exudative AMD Methods Patients were imaged using SS-OCT (PLEX Elite 9000 instrument, Carl Zeiss Meditec, Dublin, CA) with follow-up imaging performed after six months and one year. Both the 6x6 mm and 12x12 mm scan patterns were obtained at each visit. Area measurements of GA were performed on the en face images generated from a ...

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    10. A simple system of swept source optical coherence tomography for a large imaging depth range

      A simple system of swept source optical coherence tomography for a large imaging depth range

      In swept source optical coherence tomography (SSOCT), the imaging depth range sometimes limits its application, such as the whole eye measurement. The methods of extending depth range usually need to redesign the system or add some additional devices. In this paper, we propose a simple system of SSOCT for a large imaging depth range. The system is the same as the original SSOCT with using the swept source clock signal except for a slice glass in the reference arm. The large depth range is achieved by increasing the number of sampling point in every spectrum and wavenumber calibration. More sampling ...

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    11. A Supervised Joint Multi-layer Segmentation Framework for Retinal Optical Coherence Tomography Images using Conditional Random Field

      A Supervised Joint Multi-layer Segmentation Framework for Retinal Optical Coherence Tomography Images using Conditional Random Field

      Background and Objective: Accurate segmentation of the intra-retinal tissue layers in Optical Coherence Tomography (OCT) images plays an important role in the diagnosis and treatment of ocular diseases such as Age-Related Macular Degeneration (AMD) and Diabetic Macular Edema (DME). The existing energy minimization based methods employ multiple, manually handcrafted cost terms and often fail in the presence of pathologies. In this work, we eliminate the need to handcraft the energy by learning it from training images in an end-to-end manner. Our method can be easily adapted to pathologies by re-training it on an appropriate dataset. Methods: We propose a Conditional ...

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    12. Potential clinical applications of optical coherence tomography angiography in glaucoma

      Potential clinical applications of optical coherence tomography angiography in glaucoma

      Editorial: Elevated intraocular pressure has been identified as a major risk factor for primary open-angle glaucoma (POAG), and current treatments focus on reducing the intraocular pressure to prevent disease progression. However, some glaucomatous patients continue to progress despite intraocular pressure lowering, and in these patients, other risk factors like decreased ocular perfusion pressure and vascular dysfunction may be causative factors. 1 , 2 The recent advent of optical coherence tomography angiography (OCTA) has allowed for fast and noninvasive assessment of microvasculature in the peripapillary retina and macula. 3 Different strategies have been used for assessing microvasculature in different OCTA machines. The ...

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    13. Clinical and surgical implications of intraoperative optical coherence tomography imaging for benign pediatric vocal fold lesions

      Clinical and surgical implications of intraoperative optical coherence tomography imaging for benign pediatric vocal fold lesions

      Introduction Benign vocal disorders in children include an extensive list of abnormalities creating a variety of debilitating levels of dysphonia. Precise delineation of the benign lesion type and margins may have significant public health implications in children. An innovative technology such as optical coherence tomography (OCT) is being explored to delineate pediatric benign laryngeal lesions. An accurate assessment of the subepithelial morphology may help towards tailoring more personalized therapeutic treatments. This study was established to highlight key morphological and optical features of benign pediatric laryngeal lesions using intraoperative OCT and to suggest clinical implications that arise from such optical imaging ...

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    14. Determination of mechanical properties of biofilms by modeling the deformation measured using optical coherence tomography

      Determination of mechanical properties of biofilms by modeling the deformation measured using optical coherence tomography

      The advantage of using non-invasive imaging such as optical coherence tomography (OCT) to asses material properties from deformed biofilm geometries can be compromised by the assumptions made on fluid forces acting on the biofilm. This study developed a method for the determination of elastic properties of biofilms by modelling the biofilm deformation recorded by OCT imaging with poroelastic fluid-structure interaction computations. Two-dimensional biofilm geometries were extracted from OCT scans of non-deformed and deformed structures as a result of hydrodynamic loading. The biofilm geometries were implemented in a model coupling fluid dynamics with elastic solid mechanics and Darcy flow in the ...

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    15. Spectral-domain optical coherence tomography of peripheral lattice degeneration of myopic eyes before and after laser photocoagulation

      Spectral-domain optical coherence tomography of peripheral lattice degeneration of myopic eyes before and after laser photocoagulation

      Purpose To investigate the microstructural characteristics of lattice degenerations before and after laser photocoagulation in myopic eyes by spectral-domain optical coherence tomography (SD-OCT). Methods Twenty-five eyes of 25 consecutive patients at the High Myopia Clinic of the National Taiwan University Hospital were retrospectively reviewed. Myopic eyes with peripheral lattice degeneration were enrolled in the study. Best-corrected visual acuity (BCVA), axial length measurement, color fundus photography was performed. SD-OCT analyses on the lattice degeneration were performed before and after prophylactic laser photocoagulation. All patients were followed for at least 6 months. Results In total, 25 myopic eyes with peripheral lattice degenerations ...

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    16. Orbital arteriovenous fistula presenting with choroidal pulsations on optical coherence tomography

      Orbital arteriovenous fistula presenting with choroidal pulsations on optical coherence tomography

      Purpose To describe a case of orbital arteriovenous fistula diagnosed based on choroidal pulsations on optical coherence tomography (OCT). Observations A 69-year-old female originally referred for evaluation of macular degeneration . During acquisition of OCT images, choroidal pulsations of the right eye were noted on the B-scan on the instrument display. The pulsations were not noted on gross or funduscopic examination. Fluorescein angiography was unremarkable. Indocyanine green angiography revealed engorged choroidal vasculature in the right eye. OCT angiography revealed relative tortuosity and dilation of the superficial and deep vascular complexes respectively. B-scan ultrasonography revealed orbital pulsations on the right. MRI imaging ...

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      Mentions: Duke University
    17. Effect of biofilm structural deformation on hydraulic resistance during ultrafiltration: A numerical and experimental study

      Effect of biofilm structural deformation on hydraulic resistance during ultrafiltration: A numerical and experimental study

      Biofilm formation in membrane systems negatively impacts the filtration system performances. This study evaluated how biofilm compression driven by permeate flow increases the hydraulic resistance and leads to reduction in permeate flux. We analysed the effect of biofilm compression on hydraulic resistance and permeate flux through computational models supported by experimental data. Biofilms with homogeneous surface structure were subjected to step-wise changes in flux and transmembrane pressure during compression and relaxation tests. Biofilm thickness under applied forces was measured non-invasively in-situ using optical coherence tomography (OCT). A numerical model of poroelasticity, which couples water flow through the biofilm with biofilm ...

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    18. Rational and Design of the European Randomized Optical Coherence Tomography Optimized Bifurcation Event Reduction Trial (OCTOBER)

      Rational and Design of the European Randomized Optical Coherence Tomography Optimized Bifurcation Event Reduction Trial (OCTOBER)

      Background Percutaneous coronary intervention (PCI) in complex bifurcation lesions is prone to suboptimal implantation results and is associated with increased risk of subsequent clinical events. Angiographic ambiguity is high during bifurcation stenting but it is unknown if procedural guidance by intravascular optical coherence tomography (OCT) improves clinical outcome. Methods and design OCTOBER is a randomized, investigator initiated, multi-center trial aimed to show superiority of OCT guided stent implantation compared to standard angiographic guided implantation in bifurcation lesions. The primary outcome measure is a two-year composite endpoint of cardiac death, target lesion myocardial infarction, and ischemia driven target lesion revascularization. The ...

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    19. Correlation of spectral domain optical coherence tomography with histology and electron microscopy in the porcine retina

      Correlation of spectral domain optical coherence tomography with histology and electron microscopy in the porcine retina

      Spectral domain optical coherence tomography (SD-OCT) is used as a non-invasive tool for retinal morphological assessment in vivo . Information on the correlation of SD-OCT with retinal histology in the porcine retina, a model resembling the human retina, is limited. Herein, we correlated the hypo- and hyper-reflective bands on SD-OCT with histology of the lamellar architecture and cellular constituents of the porcine retina. SD-OCT images were acquired with the Heidelberg Spectralis HRA + OCT. Histological analysis was performed using epoxy resin embedded tissue and transmission electron microscopy. Photomicrographs from the histologic sections were linearly scaled to correct for tissue shrinkage and correlated ...

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    20. Spectral Domain-Optical Coherence Tomography Measurements in Alzheimer’s Disease: A Systematic Review and Meta-analysis

      Spectral Domain-Optical Coherence Tomography Measurements in Alzheimer’s Disease: A Systematic Review and Meta-analysis

      Topic Optical coherence tomography (OCT) is a non-invasive tool to measure specific retinal layers in the eye. The relationship of retinal spectral domain-OCT (SD-OCT) measurements with Alzheimer’s Disease (AD) and mild cognitive impairment (MCI) remains unclear. Hence, we conducted a systematic review and meta-analysis to examine the SD-OCT measurements in AD and MCI. Clinical Relevance Current methods of diagnosing early AD are expensive and invasive. Retinal measurements of SD-OCT, which are non-invasive, technically simple and inexpensive, are potential biomarkers of AD. Methods We conducted a literature search in PubMed and EMBASE to identify studies published before 31 December 2017 ...

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    21. Evaluation of a combination digital retinal camera with spectral-domain optical coherence tomography (SD-OCT) that might be used for the screening of diabetic retinopathy with telemedicine: A pilot study

      Evaluation of a combination digital retinal camera with spectral-domain optical coherence tomography (SD-OCT) that might be used for the screening of diabetic retinopathy with telemedicine: A pilot study

      Aims A pilot study to determine whether an instrument that combines a non-mydriatic retinal camera and spectral domain optical coherence tomography (SD-OCT) is effective for screening patients with diabetic retinopathy (DR). Methods Observational case series conducted between 2012 and 2013. DR imaged with a combination non-mydriatic retinal camera and SD-OCT instrument viewed remotely were compared to a dilated examination by a retina specialist. Results Overall, the combination instrument was better than the retina specialist in detecting more severe retinopathy, primarily because of the SD-OCT. For severe retinopathy (grade ≥ 3), the image grader had better sensitivity (87.3% [95% CI: 75 ...

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    22. Effect of plaque composition, morphology, and burden on DESolve novolimus-eluting bioresorbable vascular scaffold expansion and eccentricity — An optical coherence tomography analysis

      Effect of plaque composition, morphology, and burden on DESolve novolimus-eluting bioresorbable vascular scaffold expansion and eccentricity — An optical coherence tomography analysis

      Objective This study of patients treated with novolimus-eluting bioresorbable scaffold (BRS) investigated the impact of plaque burden on the acute mechanical performance of the BRS and the short-term outcome. Methods A total of 15 patients were enrolled. The following parameters were derived from optical coherence tomography (OCT) during the final pullback: mean and minimum area, residual area stenosis, incomplete strut apposition, tissue prolapse, scaffold expansion index (SEI), scaffold eccentricity index (SEC), symmetry index, strut fracture, and edge dissection. Fibrous plaque (FP) and calcific plaque (CP) characteristics were measured at each 200 μm longitudinal cross-section. The patients were divided into two ...

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    1-24 of 871 1 2 3 4 ... 35 36 37 »
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