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    1. Diagnosis of Intraplaque Hemorrhage by High-Definition Intravascular Ultrasound and Optical Coherence Tomography

      Diagnosis of Intraplaque Hemorrhage by High-Definition Intravascular Ultrasound and Optical Coherence Tomography

      A 67-year-old woman, a heavy smoker and with hypothyroidism, presented with a non–STsegment elevation myocardial infarction with negative T waves on the inferior leads. Coronary angiography revealed a focal stenosis in the mid right coronary artery (arrow in Figure 1A) but no other coronary lesions. High-definition (60-MHz) intravascular ultrasound (IVUS) (ACIST Medical Systems, Eden Prairie, Minnesota) revealed a large hyperechoic noncalcific plaque encompassing a well-delineated, crescent-shaped area showing a striking hypoechogenicity (echolucent “black” area) (yellow asterisks in Figures 1B and 1C [white asterisk denotes wire artifact]). The immediately adjacent plaque had a more reflective pattern with marked speckling (Figures ...

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      Mentions: Fernando Alfonso
    2. Optical Coherence Tomography Facilitating Early Withdrawal of Antiplatelet Agents in a High–Bleeding Risk Patient

      Optical Coherence Tomography Facilitating Early Withdrawal of Antiplatelet Agents in a High–Bleeding Risk Patient

      Optical coherence tomography (OCT) can guide percutaneous coronary interventions to optimize results, thus minimizing the risk of stent thrombosis. We present the case of a cancer patient, paroxysmal atrial fibrillation, and unstable angina who underwent OCT–guided complex percutaneous coronary intervention and who required early discontinuation of antiplatelet therapy because of major bleeding. 

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    3. Absolute depth LIBS-stratigraphy with NoScSiSp-OCT

      Absolute depth LIBS-stratigraphy with NoScSiSp-OCT

      LIBS is a proven method for elemental analysis. It needs little to no sample preparation and relies solely on optical access to the sample. LIBS has therefore been handled as a promising analytical method for layered or structured samples with the potential to replace metallurgic cross-sections followed by SEM/EDX raster screenings. Due to the strong dependency of the ablation process on changing crater geometries, laser fluence, and plasma dynamics ( e.g. laser absorption and scattering by the plasma, material dependent optical depth, reflecting coefficients, scattering processes, etc. ), attributing an absolute depth to the number of laser pulses applied to ...

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    4. Looking in the mirror: An unusual optical coherence tomography image

      Looking in the mirror: An unusual optical coherence tomography image

      A 75-year-old male underwent primary angioplasty of a subocclusive proximal to medial left anterior descending artery (LAD) stenosis, involving the origin of the first diagonal (D1). A provisional stenting technique was used, with two guidewires in the distal LAD and D1 and implantation of 3 mm×30 mm and 2.75 mm×28 mm drug-eluting stents (DES) in the LAD. Withdrawal of the jailed D1 guidewire caused a deep intubation of the guide catheter into the LAD. The subsequent angiogram was notable for a suspicious haziness proximal to the stents ( Figure 1 A , arrow). We decided to perform optical coherence ...

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    5. Analysis of the perfusion of the optic nerve using angio-OCT in glaucoma

      Analysis of the perfusion of the optic nerve using angio-OCT in glaucoma

      The introduction of optical coherence tomography angiography (OCT-A) has generated interest in evaluating vascular dysfunctions in the optic nerve head for the diagnosis and monitoring of glaucoma. The purpose of this study is to compare perfusion of the optic disc between normal subjects and subjects with glaucoma using OCT-A in order to detect changes in perfusion of the optic disc. Using the OCT-A AngioVue® system, an examination was performed on 40 eyes of 40 patients (20 with glaucoma and 20 healthy controls). Total radial peripapillary flow density (4.5 × 4.5 mm) was measured at different levels of segmentation. The ...

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    6. Quantification of Geographic Atrophy using Spectral Domain Optical Coherence Tomography in Age-Related Macular Degeneration

      Quantification of Geographic Atrophy using Spectral Domain Optical Coherence Tomography in Age-Related Macular Degeneration

      Purpose To compare geographic atrophy (GA) area and enlargement rate measured with SD OCT to fundus autofluorescence (FAF), color fundus photography (CFP), and infrared reflectance (IR) imaging. Design; Retrospective, multicenter, natural history case series. Participants 70 eyes with GA from 48 participants were included. Methods Participants underwent SD OCT, FAF, CFP, and IR imaging at baseline and 12 months in the study eye. SD OCT images were graded for GA area using two distinct criteria: 1) complete retinal pigment epithelium and outer retinal atrophy (cRORA) and 2) hypertransmission through Bruch’s membrane. Areas were measured with SD OCT using a ...

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    7. Mathematical Analysis of Texture Indicators for the Segmentation of Optical Coherence Tomography Images

      Mathematical Analysis of Texture Indicators for the Segmentation of Optical Coherence Tomography Images

      Optical Coherence Tomography (OCT) is a non-invasive technology which facilitates the process of capturing images from light-scattering organs like retina. Retina is a layered structure each layer of which has its own morphological properties. The segmentation of retinal layers helps to identify retinal diseases. In this paper, a novel mathematical model is proposed which can extract boundary pixels located on the borders between layers. The new model uses texture properties of pixels to extract distinguishing characteristics for boundary pixels. It is explored that boundary pixels provide certain values for texture indicators leading to the existence of special relation between neighbor ...

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    8. In-vivo analysis of iron-gold composite nanoparticles as potential exogenous contrast agents for Magnetomotive Optical Coherence Tomography (MMOCT)

      In-vivo analysis of iron-gold composite nanoparticles as potential exogenous contrast agents for Magnetomotive Optical Coherence Tomography (MMOCT)

      Magnetomotive optical coherence tomography (MMOCT) is a functional modification of conventional optical coherence tomography (OCT). It utilizes the nano-scale displacement embedded magnetic nanoparticles (MNPs) and subsequent amplitude and phase changes in OCT interferogram scattered from samples. We report a new robust method for ‘phase-lock-in’ detection of MMOCT signals and subsequent imaging. We validated this method utilizing iron-gold (Fe-Au) composite nanoparticles as an exogenous contrast agent for MMOCT. High contrast and specific background-subtracted images was generated for Fe-Au MNPs targeted samples. MMOCT with MNPs imaging systems was corroborated with tissue phantoms and in-vivo swiss albino mice model with modulating external magnetic ...

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    9. Posterior capsule rupture with FLACS due to erroneous interpretation of a high OCT intensity area in anterior vitreous

      Posterior capsule rupture with FLACS due to erroneous interpretation of a high OCT intensity area in anterior vitreous

      Purpose We describe a case of posterior capsule rupture during femtosecond laser-assisted cataract surgery (FLACS) due to direct exposure of the posterior capsule to the laser beam. Observations A 47-year-old man underwent FLACS for anterior capsule opacity. The CATALYS® system automatically detected the posterior capsule from the optical coherence tomography (OCT) images, after which the operator manually adjusted the line of posterior capsule. Femtosecond laser irradiation was presumed to be completed successfully. However, upon insertion of a phaco-tip, the diced nucleus of the lens dropped into the vitreous chamber. Reviewing intraoperative OCT images of the treatment summary to check the ...

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    10. A Comparison of OCT Parameters in Identifying Glaucoma Damage in Eyes Suspected of Having Glaucoma

      A Comparison of OCT Parameters in Identifying Glaucoma Damage in Eyes Suspected of Having Glaucoma

      Purpose To compare retinal nerve fiber layer thickness (RNFLT) and Bruch’s membrane opening (BMO) minimum rim width (MRW) measured by spectral-domain (SD) OCT for diagnosing glaucoma in those suspected of having the disease. Design Observational cohort study. Participants One hundred thirteen eyes from 81 patients suspected of having glaucoma based on optic nerve appearance. Methods Participants were imaged using SD OCT, and RNFLT and BMO MRW were measured. All participants showed normal visual fields at the time of imaging but were considered suspects based on the appearance of the optic disc during clinical examination. Eyes were classified as glaucomatous ...

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    11. Association of systemic inflammatory biomarkers with morphological characteristics of the coronary atherosclerotic plaque by intravascular optical coherence tomography.

      Association of systemic inflammatory biomarkers with morphological characteristics of the coronary atherosclerotic plaque by intravascular optical coherence tomography.

      Despite significant advances in preventive, medical and interventional management, coronary artery disease remains the leading cause of death worldwide. We now know that in the majority of acute coronary syndromes, a thrombotic event is triggered either by the rupture or erosion of the so-called high-risk or ‘vulnerable’ plaque. However, accurately identifying the individual who is at significant risk of acute event remains the holy grail of preventive cardiology. To better stratify an individual’s risk of developing and suffering a cardiovascular event, biomarkers are needed that can accurately predict coronary events, and if possible monitor disease activity in response to ...

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    12. The protective effect of astaxanthin on the ganglion cell complex in glutamate/aspartate transporter deficient mice, a model of normal tension glaucoma, analyzed by spectral domain-optical coherence tomography

      The protective effect of astaxanthin on the ganglion cell complex in glutamate/aspartate transporter deficient mice, a model of normal tension glaucoma, analyzed by spectral domain-optical coherence tomography

      Astaxanthin (AST), a natural marine carotenoid, possess a wide variety of biological functions. In particular, as a strong antioxidant, AST effectively scavenges oxygen free radicals and reduces oxidative stress. In addition, recent in vitro studies have suggested that AST attenuates glutamate-induced apoptosis and cytotoxicity. The glutamate/aspartate transporter (GLAST) deficient (GLAST -/- ) mouse is a mouse model of normal tension glaucoma (NTG) caused by both the glutamate neurotoxicity and oxidative stress in the retina. In the present study, we investigated the effects of AST on the ganglion cell complex, indicator of glaucomatous structural damage, using spectral domain-optical coherence tomography. As a ...

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    13. Determination of peripapillary vessel density in optic disc drusen using EDI-OCT and OCT angiography

      Determination of peripapillary vessel density in optic disc drusen using EDI-OCT and OCT angiography

      Optical coherence tomography angiography (OCTA) is a rapidly developing technique which generates angiographic images non-invasively. This study proposes a method to determine the vessel density in OCTA scans in general and especially the local peripapillary vessel density. The method produces vessel density heatmaps that contain information about the local vessel density. We apply the method in a small study to demonstrate its applicability and its potential to investigate the influence of local conditions on the vessel density. In the study, we combine information from enhanced depth imaging optical coherence tomography (EDI-OCT) about the location of optic disc drusen (ODD) with ...

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    14. Reorganization of the perifoveal microvasculature after macular hole closure assessed via optical coherence tomography angiography

      Reorganization of the perifoveal microvasculature after macular hole closure assessed via optical coherence tomography angiography

      Purpose To quantify short-term microvascular changes after pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling in patients with idiopathic macular hole (IMH) using optical coherence tomography angiography (OCTA). Design Cohort Study. Participants This study included patients with IMH. Affected eyes were compared with fellow eyes. Methods 6 × 6 mm OCTA (Zeiss Angioplex, Zeiss Meditec, Dublin, CA, USA) images of the study eye and fellow eye were acquired one day before surgery, 4 weeks and 12 weeks after surgery. Microvascular alterations in the superficial and deep capillary plexus were assessed by measuring vessel density and the shortest distance to ...

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    15. Speckle reduction of OCT via super resolution reconstruction and its application on retinal layer segmentation

      Speckle reduction of OCT via super resolution reconstruction and its application on retinal layer segmentation

      Optical coherence tomography (OCT) is a rapidly developing non-invasive three dimensional imaging approach, and it has been widely used in examination and diagnosis of eye diseases. However, speckle noise are often inherited from image acquisition process, and may obscure the anatomical structure, such as the retinal layers. In this paper, we propose a novel method to reduce the speckle noise in 3D OCT scans, by introducing a new super-resolution approach. It uses a multi-frame fusion mechanism that merges multiple scans for the same scene, and utilizes the movements of sub-pixels to recover missing signals in one pixel, which significantly improves ...

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    16. Optical coherence tomography findings in a case of macular hole treated with an autologous retinal transplant

      Optical coherence tomography findings in a case of macular hole treated with an autologous retinal transplant

      A case is presented of a 56-year-old female patient with a long-standing large macular hole who underwent autologous retina transplant surgery. Fundus images and spectral-domain optical coherence tomography images showed the presence of graft oedema with its corresponding hyper-reflectivity of the inner retinal layers in the first weeks of follow-up. Hyper-reflective dots later appeared mainly in the inner retinal layers. The integrity of the outer retinal layers and a woolly-looking material on the surface of the graft were observed. At the end of follow-up, the graft had integrated with the recipient tissue with functional improvement.

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    17. Predicting Progression of Age-Related Macular Degeneration Using Optical Coherence Tomography and Fundus Photography

      Predicting Progression of Age-Related Macular Degeneration Using Optical Coherence Tomography and Fundus Photography

      Purpose To compare the performance of automatically quantified optical coherence tomography (OCT) imaging biomarkers and conventional risk factors manually graded on color fundus photographs (CFP) for predicting progression to late age-related macular degeneration (AMD). Design Longitudinal observational study. Participants 280 eyes from 140 participants with bilateral large drusen. Methods All participants underwent OCT and CFP imaging at baseline and were then reviewed at six-monthly intervals to determine progression to late AMD. CFPs were manually graded and OCT scans underwent automated image analyses to quantify risk factors and imaging biomarkers respectively based on drusen and AMD pigmentary abnormalities. Four predictive models ...

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    18. In vivo based biomechanics of right and left coronary arteries

      In vivo based biomechanics of right and left coronary arteries

      A realistic/comprehensive biomechanical model of right/left coronary arteries is developed using the in vivo geometric and haemodynamic properties obtained from optical coherence tomography (OCT), angiography, and electrocardiography (ECG). The developed biomechanical model is constructed with the help of an image processing technique and simulated via the finite element method (FEM) for determination of regions with highest shear/von Mises stresses (which determine the potential areas for plaque rupture and initiation of myocardial infarction). A set of simulation results is compared to clinically obtained data to assess the validity of modelling/simulations. The model comprehensively incorporates information relating to ...

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    19. Optical coherence tomography in mild cognitive impairment – systematic review and meta-analysis

      Optical coherence tomography in mild cognitive impairment – systematic review and meta-analysis

      Thinning of retinal layers, measured using optical coherence tomography (OCT), is associated with some neurodegenerative disorders such as established Alzheimer’s disease and multiple sclerosis. The evidence for retinal layer thinning in both mild cognitive impairment (MCI), a precursor of dementia, and delirium, a potential pre-clinical stage of neurodegenerative disorder, is unclear. We performed a systematic review of the associations, in older people, between retinal layer thickness changes (measured using OCT) and delirium or MCI compared to controls (Protocol registration ID (Prospero) CRD42019122165). We did not identify any relevant studies on delirium. This report is therefore a review of retinal ...

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    20. New computerized volume measurement method for optic nerve head (ONH) region comparison with measurements by Heidelberg SPECTRALIS optical coherence tomography

      New computerized volume measurement method for optic nerve head (ONH) region comparison with measurements by Heidelberg SPECTRALIS optical coherence tomography

      Purpose To introduce an innovative computerized methodology to calculate the volume of the optic nerve head (ONH) region from SPECTRALIS optical coherence tomography (OCT) images, a new parameter called as OCT ONH coronal volume is proposed. Method 47 OCT ONH examinations were obtained, 25 right eyes and 22 left eyes. For each OCT ONH examination, the automated diagnosis by OCT SPECTRALIS was also obtained. This included three parameters: retinal nerve fiber layer (RNFL) thickness, retina thickness, and ONH region's volume. The OCT ONH coronal volume - a new quantitative parameter - was reported for each OCT ONH test. It was generated ...

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    21. Defocus and contrast agent absorption compensation method in intravascular optical coherence tomography imaging

      Defocus and contrast agent absorption compensation method in intravascular optical coherence tomography imaging

      Intravascular optical coherence tomography (IVOCT) has been widely used in clinical coronary artery intervention field. Owing to defocus and contrast agent absorption effects, the intensity fluctuation caused by imaging catheter locating at an eccentric position significantly influence the quality of IVOCT imaging and even plaque type identification. In this paper, we present a novel method to compensate intensity fluctuation caused by defocus and contrast agent absorption in IVOCT imaging. We construct a principle model of IVOCT intensity signal based on defocus function and contrast agent absorption. By measuring the parameters of defocus function and contrast agent absorption, we compensate intensity ...

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    22. Radio frequency based material estimation of old age 3D sculptures

      Radio frequency based material estimation of old age 3D sculptures

      The cultural heritage has its importance due to the information communicated by the heritage to the future generations. It is difficult to preserve cultural heritage over the centuries because of their volatile nature. In this paper, the preservation aids are considered for sculptures. The sculpture also includes the type of monument. The challenges are face deterioration during logistic and handling. Hence, it destroys the information carried by sculpture. In addition, the knowledge about materials used for construction of these sculptures help in maintenance of these sculpture. It helps in reconstructing the shape and color, which have been damaged earlier. The ...

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    23. Analyzing Relative Flow Speeds in Diabetic Retinopathy Using Variable Interscan Time Analysis Optical Coherence Tomography Angiography

      Analyzing Relative Flow Speeds in Diabetic Retinopathy Using Variable Interscan Time Analysis Optical Coherence Tomography Angiography

      Objective Further insight into the flow characteristics of the vascular features associated with diabetic retinopathy (DR) may improve assessment and treatment of disease progression. The variable interscan time analysis (VISTA) algorithm is an extension of optical coherence tomography angiography (OCTA) that detects relative blood flow speeds which can then be depicted on a color-coded map. This study utilized VISTA to analyze relative blood flow speeds in the microvascular changes associated with DR. Design and Participants: In this cross-sectional study at New England Eye Center, Boston, Massachusetts, thirteen patients of varying severities of DR were enrolled. Methods OCTA images centered at ...

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