1. 1-24 of 656 1 2 3 4 ... 26 27 28 »
    1. Optical coherence tomography angiography of the peripapillary retina and optic nerve head in dominant optic atrophy

      Optical coherence tomography angiography of the peripapillary retina and optic nerve head in dominant optic atrophy

      Peripapillar and nerve head vessel density (VD) was measured in 10 patients affected by Dominant optic atrophy (DOA) using optical coherence tomography angiography (OCT-A) and compared to the measurements of 15 age- and gender-matched controls. DOA patients showed VD reduction, mostly in the temporal and inferotemporal peripapillary sectors, according to the preferential involvement of the papillomacular bundle. Despite poor best-corrected visual acuity (BCVA), OCT-A revealed good repeatability. VD correlated with functional (mean deviation of visual field and BCVA) and structural (retinal nerve fiber layer thickness) parameters and could be a non-invasive, quantitative tool for the monitoring of the disease and ...

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    2. The REMEDEE-OCT Study : An Evaluation of the Bioengineered COMBO Dual-Therapy CD34 Antibody–Covered Sirolimus-Eluting Coronary Stent Compared With a Cobalt-Chromium Everolimus-Eluting Stent in Patients With Acute Coronary Syndromes: Insights From Optical

      The REMEDEE-OCT Study : An Evaluation of the Bioengineered COMBO Dual-Therapy CD34 Antibody–Covered Sirolimus-Eluting Coronary Stent Compared With a Cobalt-Chromium Everolimus-Eluting Stent in Patients With Acute Coronary Syndromes: Insights From Optical

      Objectives The aim of the present study was to evaluate vascular healing of the bioengineered COMBO Dual Therapy Stent compared with a cobalt-chromium (CoCr) everolimus-eluting stent (EES) as assessed by optical coherence tomography in patients with acute coronary syndromes. Background CD34+ cells promote endothelial repair after vascular injury. The bioengineered COMBO Dual Therapy Stent combines CD34+ cell–capturing technology with abluminal sirolimus release, but more data from clinical studies evaluating the vascular response are needed. Methods In a prospective randomized multicenter clinical trial, 60 patients with acute coronary syndromes were randomized 1:1 to COMBO or CoCr EES implantation. The ...

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    3. Imaging Resin Infiltration into Non-Cavitated Carious Lesions by Optical Coherence Tomography

      Imaging Resin Infiltration into Non-Cavitated Carious Lesions by Optical Coherence Tomography

      Objectives Visualisation of the etching process and resin penetration at white spot carious lesions by spectral domain optical coherence tomography (SD-OCT). Materials and methods The non-cavitated carious lesions (ICDAS code 2) of four visually preselected extracted human molars and premolars were verified as enamel lesions by micro computed tomography (μCT). One region of interest (ROI) per tooth was marked by two drill-holes in occlusal-cervical direction. The lesions were imaged by SD-OCT. Lesions were infiltrated (Icon, DMG) according to the manufacturer’s instructions. During each treatment step and after light curing of the infiltrant, the ROIs were imaged again by SD-OCT ...

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    4. Deep Learning Is Effective for Classifying Normal versus Age-Related Macular Degeneration Optical Coherence Tomography Images

      Deep Learning Is Effective for Classifying Normal versus Age-Related Macular Degeneration Optical Coherence Tomography Images

      Purpose The advent of electronic medical records (EMRs) with large electronic imaging databases along with advances in deep neural networks with machine learning has provided a unique opportunity to achieve milestones in automated image analysis. Optical coherence tomography (OCT) is the most common imaging modality in ophthalmology and represents a dense and rich data set when combined with labels derived from the EMR. We sought to determine whether deep learning could be utilized to distinguish normal OCT images from images from patients with age-related macular degeneration (AMD). Design EMR and OCT database study. Subjects Normal and AMD patients who underwent ...

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    5. Accuracy of computed tomography angiography to identify thin-cap fibroatheroma detected by optical coherence tomography

      Accuracy of computed tomography angiography to identify thin-cap fibroatheroma detected by optical coherence tomography

      Background Thin-cap fibroatheroma (TCFA) is assumed to cause acute coronary syndromes. Objective To compare the accuracy of different models for diagnosing TCFA using parameters derived by CT, validated against optical coherence tomography (OCT). Methods One hundred twenty-nine plaques in 106 patients were analyzed using data acquired by 64-row CT with a reconstruction thickness of 0.67 mm and an increment of 0.33 mm. TCFA was defined by OCT as a plaque with lipid content in ≥2 quadrants and the thinnest part of the fibrous cap measuring ≤65 μm. The following parameters were obtained from CT: remodeling index (RI), proportion ...

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    6. Spectral Domain Optical Coherence Tomography Angiography in Stargardt's Macular Dystrophy

      Spectral Domain Optical Coherence Tomography Angiography in Stargardt's Macular Dystrophy

      Stargardt's macular dystrophy (SMD) is the most common form of hereditary recessive macular dystrophy, seen in approximately 1 in 10 000 people, and accounts for 7% of all retinal degenerations. 1 The pathophysiology is a well-described mutation in the ABCA4 gene, resulting in the accumulation of lipofuscin (modified residues of incompletely digested photoreceptor outer segments), retinal pigment epithelium (RPE) cell death, and irreversible progressive atrophy in the macula. 2 Optical coherence tomography angiography (OCTA) is a unique imaging technique that provides high-resolution imaging of capillary networks and allows for segmentation of different layers of retinal and choroidal vasculature. 3 ...

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    7. Involuntary Eye Motion Correction in Retinal Optical Coherence Tomography: Hardware or Software Solution?

      Involuntary Eye Motion Correction in Retinal Optical Coherence Tomography: Hardware or Software Solution?

      In this paper, we review state-of-the-art techniques to correct eye motion artifacts in Optical Coherence Tomography (OCT) imaging. The methods for eye motion artifact reduction can be categorized into two major classes: 1) hardware-based techniques and 2) software-based techniques. In the first class, additional hardware is mounted onto the OCT scanner to gather information about the eye motion patterns during OCT data acquisition. This information is later processed and applied to the OCT data for creating an anatomically correct representation of the retina, either in an offline or online manner. In software based techniques, the motion patterns are approximated either ...

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    8. Optical coherence tomography in the diagnosis of actinic keratosis – A systematic review

      Optical coherence tomography in the diagnosis of actinic keratosis – A systematic review

      Background Optical coherence tomography (OCT) is a real-time non-invasive imaging tool, introduced in dermatology in the late 1990s. OCT uses near-infrared light impulses to produce images which can be displayed in cross-sectional and en-face mode. The technique has been used to image skin diseases especially non-melanoma skin cancer including actinic keratosis (AK). Morphological characteristics of AK can be visualized in OCT images and can be used for diagnosis as well as disease monitoring. Methods A systematic review of original papers on AK and OCT was performed on 31.03.16 and 24.10.16 in the major databases Pubmed, MEDLINE ...

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    9. Visualization of extensive intraplaque neovascularization by optical coherence tomography

      Visualization of extensive intraplaque neovascularization by optical coherence tomography

      Inflammation plays a key role in pathogenesis and progression of atherosclerosis (1) . Advent of novel intravascular imaging tools such as Optical Coherence Tomography (OCT) has led to visualization of coronary atherosclerotic plaque characteristics in vivo that were previously seen only on histology. Herein we discuss a case of extensive neovascularization, a feature that imparts vulnerability to atherosclerotic plaque in the coronary artery, as seen by two- and three-dimensional OCT images. A 63-year-old female with history of diabetes mellitus and hypertension presented with troponin-positive chest pain. She underwent coronary angiography followed by drug-eluting stent implantation to the mid segment of right ...

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    10. Multimodal Anatomic and Functional Imaging in a Case of “Eclipse Retinopathy”

      Multimodal Anatomic and Functional Imaging in a Case of “Eclipse Retinopathy”

      Eclipse retinopathy is a term used for a specific foveolar lesion caused by direct sun gazing. Ocular damage due to solar observation is well-known. Galileo, the famous scientist, suffered from permanent damage to his eyes by solar observation through the telescope. Solar retinopathy primarily occurs through a photo-oxidative pathway rather than by direct thermal injury. 1 Symptoms usually develop within 1 to 4 hours after exposure and include decreased vision, metamorphopsia, and micropsia with central or paracentral scotomas. We report a case of a 42-year-old woman who presented to our clinic with unprotected solar eclipse exposure to her right eye ...

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    11. Optical coherence tomography is a kid on the block: I would choose intravascular ultrasound

      Optical coherence tomography is a kid on the block: I would choose intravascular ultrasound

      Intravascular imaging has improved our understanding of in vivo pathophysiology of coronary artery disease (CAD) and predicted decision-making in percutaneous coronary intervention (PCI). Intravascular ultrasound (IVUS) has emerged as the first clinical imaging method contributing significantly to modern PCI techniques. This modality has outlived many other intravascular techniques 26 years after its inception. It has assisted us in understanding dynamics of atherosclerosis and provides several unique insights into plaque burden, remodeling, and restenosis. It is useful as an imaging endpoint in large progression-regression trial and as workhorse in many catheterization laboratories. IVUS guidance appears to be most beneficial in complex ...

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    12. Automatic Segmentation of Accumulated Fluid inside the Retinal Layers from Optical Coherence Tomography Images

      Automatic Segmentation of Accumulated Fluid inside the Retinal Layers from Optical Coherence Tomography Images

      Visual impairments are mostly associated with the retinal diseases such as glaucoma, age related macular degeneration, fluid accumulation inside the retinal layers and other diseases. To evaluate the visual loss associated with the sub-retinal fluid accumulation, OCT images are widely used. So long, the effected retinal segment is visually estimated from the images. In this paper, we have proposed a novel Retinal Fluid Automatic Detection (RFAD) algorithm for automatically extracting the affected retinal segment due to fluid accumulation and thereby noticeably increasing the visual impact of the affected area than earlier by proper edge detection. The proposed method is validated ...

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    13. A simplified algorithm for digital fringe analysis in two-wave interferometry with sinusoidal phase modulation

      A simplified algorithm for digital fringe analysis in two-wave interferometry with sinusoidal phase modulation

      A compact simplified algorithm for digital detection of the amplitude and phase of the interferometric signal delivered by a two-wave interferometer with sinusoidal phase modulation is presented. The algorithm consists of simple mathematical combinations of four frames obtained by integration by a camera of the time-varying intensity in an interference pattern during the four successive quarters of the modulation period. The algorithm is invariant by circular permutation of the four image frames. Any set of four consecutive frames can be used for the calculations, which simplifies the practical implementation of the method. A numerical simulation has been carried out to ...

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    14. Choroid Segmentation from Optical Coherence Tomography with Graph-Edge Weights Learned from Deep Convolutional Neural Networks

      Choroid Segmentation from Optical Coherence Tomography with Graph-Edge Weights Learned from Deep Convolutional Neural Networks

      Examining choroid in Optical Coherence Tomography (OCT) plays a vital role in pathophysiologic factors of many ocular conditions. Among the existing approaches to detecting choroidal boundaries, graph-searching based techniques belong to the state-of-the-art. However, most of these techniques rely on hand-crafted models on the graph-edge weight and their performances are limited mainly due to the weak choroidal boundaries, textural structure of the choroid, inhomogeneity of the textural structure of the choroid and great variation of the choroidal thickness. In order to circumvent this limitation, we present a multi-scale and end-to-end convolutional network architecture where an optimal graph-edge weight can be ...

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    15. In-situ biofouling assessment in spacer filled channels using optical coherence tomography (OCT): 3D biofilm thickness mapping

      In-situ biofouling assessment in spacer filled channels using optical coherence tomography (OCT): 3D biofilm thickness mapping

      Membrane systems for water purification can be seriously hampered by biofouling. The use of optical coherence tomography (OCT) to investigate biofilms in membrane systems has recently increased due to the ability to do the characterization in-situ and non-destructively. The OCT biofilm thickness map is presented for the first time as a tool to assess biofilm spatial distribution on a surface. The map allows the visualization and evaluation of the biofilm formation and growth in membrane filtration systems through the use of a false color scale. The biofilm development was monitored with OCT to evaluate the suitability of the proposed approach ...

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    16. Sensitivity of visual evoked potentials and spectral domain optical coherence tomography in early relapsing remitting multiple sclerosis

      Sensitivity of visual evoked potentials and spectral domain optical coherence tomography in early relapsing remitting multiple sclerosis

      Background Visual evoked potentials and spectral-domain optical coherence tomography are common ancillary studies that assess the visual pathways from a functional and structural aspect, respectively. Objective To compare prevalence of abnormalities of Visual evoked potentials (VEP) and spectral-domain optical coherence tomography (SDOCT) in patients with relapsing remitting multiple sclerosis (RRMS). Methods A cross-sectional study of 100 eyes with disease duration of less than 5 years since the diagnosis. Correlation between retinal nerve fiber layer and ganglion-cell/inner plexiform layer with pattern-reversal visual evoked potentials amplitude and latency and contrast sensitivity was performed. Results The prevalence of abnormalities in pattern-reversal visual ...

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    17. Prevalence of Vitreoretinal Interface Abnormalities on Spectral-Domain Optical Coherence Tomography in Healthy Participants over 45 Years of Age

      Prevalence of Vitreoretinal Interface Abnormalities on Spectral-Domain Optical Coherence Tomography in Healthy Participants over 45 Years of Age

      Purpose To assess the prevalence of vitreoretinal interface abnormalities in a general population of healthy adults ≥45 years of age. Design Cross-sectional study carried out at 17 ophthalmology services throughout Spain. Participants Between September 2015 and March 2016, all consecutive healthy persons aged ≥45 years who were accompanying patients to ophthalmology services were invited to take part in the study. Exclusion criteria were known retinal disease, uveitis, history of ocular trauma or previous intraocular surgery (including cataract surgery and intravitreal injections), severe myopia (>−6 dioptres), and poor ocular media transparency. Methods Spectral-domain optical coherence tomography (OCT) or swept-source OCT was ...

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    18. Abnormality of retinal arterial velocity profiles using Doppler Fourier-domain optical coherence tomography in a case of Takayasu's arteritis with aortic regurgitation

      Abnormality of retinal arterial velocity profiles using Doppler Fourier-domain optical coherence tomography in a case of Takayasu's arteritis with aortic regurgitation

      Purpose To evaluate the retinal microcirculation using a segmental-scanning Doppler optical coherence tomography (DOCT) flowmeter in a patient with Takayasu's arteritis (TA) with aortic valve regurgitation (AR). Observations We measured the retinal blood velocity (V), retinal blood flow (RBF), and retinal blood velocity profiles (RBVP) of the major retinal arterioles using a DOCT flowmeter. The arteries were measured at the straight portion 1 disc diameter from the optic disc. Horizontal velocity profiles were extracted to evaluate the RBVP during one cardiac cycle. A patient with TA with stage 2 Takayasu retinopathy (TR) and AR, had normal RBF and V ...

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