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    1. 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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    2. 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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    3. 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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    4. 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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    5. 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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    6. 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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    7. 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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    8. 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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    9. 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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    10. 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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    11. 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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    12. 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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    13. 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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    14. 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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    15. Optical Coherence Tomography–Guided Short-Duration Positioning after Macular Hole Surger

      Optical Coherence Tomography–Guided Short-Duration Positioning after Macular Hole Surger

      The current standard of care treatment for macular hole (MH) is pars plana vitrectomy (PPV), internal limiting membrane peel, injection of gas air tamponade, and postoperative facedown positioning. The proposed mechanism by which facedown positioning aids in the closure of MH is by allowing contact of the tamponade agent with the MH, thereby allowing reapproximation and closure, although the exact mechanism by which this occurs is not wellunderstood. Facedown positioning is uncomfortable and places a significant burden on patients after PPV for MH. For this reason, some have advocated short-duration facedown positioning after surgery for MH,1,2 and some ...

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    16. Progression of transsynaptic retinal degeneration with spectral-domain optical coherence tomography

      Progression of transsynaptic retinal degeneration with spectral-domain optical coherence tomography

      Purpose To illustrate the progression of retrograde transsynaptic retinal degeneration using spectral-domain optical coherence tomography (SD-OCT). Observations A 60 year-old man with a stroke was followed over a 17-month period using SD-OCT of the macula, ganglion cell layer (GCC), and retinal nerve fiber layer. Transsynaptic retinal degeneration progressed over this time. Conclusions and Importance Retrograde transsynaptic retinal degeneration may occur in patients with homonymous visual field loss caused by post-geniculate neurologic disease. This is best detected as homonymous thinning of the retina, corresponding to the pattern of visual field loss, using SD-OCT of the GCC and macula. The retinal changes ...

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    17. Optical coherence tomography: A quantitative tool to measure neurodegeneration and facilitate testing of novel treatments for tissue protection in multiple sclerosis

      Optical coherence tomography: A quantitative tool to measure neurodegeneration and facilitate testing of novel treatments for tissue protection in multiple sclerosis

      Optical coherence tomography (OCT) is a relatively new imaging technology that has been introduced as a powerful biomarker in neurological disease, including multiple sclerosis. In this review, OCT as an imaging technique, its reproducibility and validation in multiple sclerosis, application to other neurodegenerative diseases and future technological directions are discussed.

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    18. Effects of spacer orientations on the cake formation during membrane fouling: Quantitative analysis based on 3D OCT imaging

      Effects of spacer orientations on the cake formation during membrane fouling: Quantitative analysis based on 3D OCT imaging

      Spacer design plays an important role in improving the performance of membrane processes for water/wastewater treatment. This work focused on a fundamental issue of spacer design, i.e., investigating the effects of spacer orientations on the fouling behavior during a membrane process. A series of fouling experiments with different spacer orientation were carried out to in situ characterize the formation of a cake layer in a spacer unit cell via 3D optical coherence tomography (OCT) imaging. The cake layers formed at different times were digitalized for quantitatively analyzing the variation in the cake morphology as a function of time ...

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    19. Thrombus and Plaque Erosion Characterized by Optical Coherence Tomography in Patients With Vasospastic Angin

      Thrombus and Plaque Erosion Characterized by Optical Coherence Tomography in Patients With Vasospastic Angin

      Introduction and objectives Vasospastic angina (VSA) can result in endothelial damage and thrombus formation. The aim of this study was to evaluate the incidence of thrombus and plaque characteristics at coronary spasm segments compared with nonspasm segments by using optical coherence tomography (OCT) in patients with suspected VSA. Methods One hundred and eighty-three patients with suspected VSA were enrolled in this study. The ergonovine provocation test was performed in all patients for the diagnosis of VSA except in patients with spontaneous spasm. All target lesions were analyzed by OCT. Plaque erosion was defined as the presence of attached thrombus overlying ...

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