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    1. Spectral interferogram prediction in high resolution dual- and multiple-band Fourier domain optical coherence tomography

      Spectral interferogram prediction in high resolution dual- and multiple-band Fourier domain optical coherence tomography

      Using dual-band in Fourier domain optical coherence tomography (FD-OCT) aims at improving resolution. Previous work showed that direct application of Fourier transform to the spectral interferogram with gap between the two bands leads in many cases to resolution poorer than using a single band. In this work we propose an algorithm to fill in the gap in the spectral interferogram based on the linear prediction technique. The results showed that in dual-band FD-OCT we can get resolution equivalent to a continuous band whose width is the sum of the widths of the two bands and plus the width of the ...

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    2. Retinal single-layer analysis with optical coherence tomography (OCT) in schizophrenia spectrum disorder

      Retinal single-layer analysis with optical coherence tomography (OCT) in schizophrenia spectrum disorder

      Background Volume reductions in brain structures of patients with schizophrenia spectrum disorder (SSD) have repeatedly been found in voxel-based morphometry MRI studies. Hence, an underlying neurodegenerative etiological component of SSD is currently being discussed. In recent years, the imaging method of optical coherence tomography (OCT) has shown its potential in evaluating structural changes in the retina in patients with confirmed neurodegenerative disorders, providing a window into the brain. Methods Twenty-six patients with schizophrenia or schizoaffective disorder and 23 age- and sex-matched healthy controls were examined with the Heidelberg Spectralis OCT system to derive a single-layer analysis of both retinas. The ...

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    3. Progression of Diabetic Microaneurysms According to the Internal Reflectivity on Structural Optical Coherence Tomography and Visibility on Optical Coherence Tomography Angiography

      Progression of Diabetic Microaneurysms According to the Internal Reflectivity on Structural Optical Coherence Tomography and Visibility on Optical Coherence Tomography Angiography

      Purpose To investigate the progression of diabetic microaneurysms (MAs) according to the spectral-domain optical coherence tomography (SD-OCT) and OCT angiography (OCTA) characteristics and to evaluate their influence on the retinal extracellular fluid accumulation at 1 year follow-up in patients with nonproliferative diabetic retinopathy (NPDR). Design Prospective, observational case series. Methods Fourteen patients with NPDR underwent SD-OCT and OCTA at the baseline and at 1 year follow-up. For all the selected MAs the visibility, the changes of internal reflectivity, graded as hyporeflective, moderate, or hyperreflective, and the extracellular fluid accumulation surrounding each MA on SD-OCT at 1 year were evaluated. The ...

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    4. Analysis of new attachment site in medial rectus resection with advancement using anterior segment optical coherence tomography

      Analysis of new attachment site in medial rectus resection with advancement using anterior segment optical coherence tomography

      Objective To evaluate the surgical outcome of unilateral medial rectus resection with small advancement for recurrent exotropia , ≤30 prism diopters (PD), and verify new attachment site anatomically using anterior segment optical coherence tomography (ASOCT). Method This study is a retrospective chart review of patients who underwent 1.0mm advancement of unilateral resected medial rectus from original medial rectus (OMR) insertion for recurrent exotropia since 2014. The age at operation, sex, preoperative angle of deviation, near stereopsis , and suppression were evaluated. Success was defined as ≤5 PD of esodeviation or ≤10 PD of exodeviation at the final visit. Preoperative scleral thickness ...

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      Mentions: Korea University
    5. Application of optical coherence tomography angiography in diabetic retinopathy: a comprehensive review

      Application of optical coherence tomography angiography in diabetic retinopathy: a comprehensive review

      Optical coherence tomography angiography (OCTA) is a noninvasive method that enables visualization of blood flow within retinal vessels down to the size of capillaries by detecting motion contrast from moving blood cells. OCTA provides a fast and safe procedure to assess retinal microvasculature with higher contrast and resolution than conventional fluorescence angiography . The different capillary plexuses are displayed separately and their perfusion density can be quantified. Imaging capabilities such as these have led to an emerging field of clinical application for OCTA in vascular diseases such as diabetic retinopathy (DR). Evaluation of parameters such as parafoveal capillary perfusion density could ...

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    6. Comparison of Coronary Culprit Lesion Morphology Determined by Optical Coherence Tomography and Relation to Outcomes in Patients Diagnosed with Acute Coronary Syndrome During Winter –vs– Other Season

      Comparison of Coronary Culprit Lesion Morphology Determined by Optical Coherence Tomography and Relation to Outcomes in Patients Diagnosed with Acute Coronary Syndrome During Winter –vs– Other Season

      Patients diagnosed with acute coronary syndrome (ACS) during winter have worse outcomes; however, mechanisms driving this trend are unclear. We examined coronary culprit lesion morphologies using optical coherence tomography (OCT). Features and outcomes were retrospectively compared between patients admitted with ACS in winter (W-ACS; n=390) and in other seasons (O-ACS; n=1027). Angiography and OCT results were analyzed in patients who underwent OCT examination (173 patients in W-ACS and 450 in O-ACS). On initial angiography, minimum lumen diameter was smaller (median; 0.12 mm vs. 0.25 mm, p=0.021) and Thrombolysis in Myocardial Infarction (TIMI) flow grade ...

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      Mentions: Masamichi Takano
    7. Optical Coherence Tomography Angiographic Findings of Tamoxifen Retinopathy: Similarity with Macular Telangiectasia Type 2

      Optical Coherence Tomography Angiographic Findings of Tamoxifen Retinopathy: Similarity with Macular Telangiectasia Type 2

      Purpose We aimed to describe the vascular changes in eyes associated with tamoxifen retinopathy using optical coherence tomography angiography (OCTA) and to compare these changes with abnormalities in macular telangiectasia type 2 (MacTel2) previously reported in the literature. Design Retrospective, observational study Participants Seventeen eyes with tamoxifen retinopathy and 17 eyes of age-matched normal controls. Methods The medical records of patients who visited the ophthalmology department with a history of taking tamoxifen were reviewed. Tamoxifen retinopathy was diagnosed based on typical spectral domain-optical coherence tomography (SD-OCT) findings, such as intraretinal cavitation and/or photoreceptor disruption. Multimodal imaging, particularly focused on ...

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    8. Glaucoma progression analysis by Spectral-Domain Optical Coherence Tomography (SD-OCT)

      Glaucoma progression analysis by Spectral-Domain Optical Coherence Tomography (SD-OCT)

      Spectral domain optical coherence tomography (SD-OCT) provides an objective quantification of the lesions of various target tissue structures in glaucoma, with unprecedented resolution, which has now demonstrated its interest in controlling the progression of glaucomatous neuropathy , from early stages to late stages. A certain number of well-established proofs state that a progressive modification in OCT is a common predictor of functional loss, and that patients with rapid OCT changes have an increased risk of developing glaucomatous scotoma . Follow-up of the progression goes through three stages. It consists first of all in detecting the evolution of damage to the retinal nerve ...

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    9. Efficacy of post-dilatation during carotid artery stenting for unstable plaque using closed-cell design stent evaluated by optical coherence tomography

      Efficacy of post-dilatation during carotid artery stenting for unstable plaque using closed-cell design stent evaluated by optical coherence tomography

      Background and Purpose: This study aimed to use optical coherence tomography (OCT) to evaluate the efficacy of post-dilatation (PD) after stent placement for unstable plaques during carotid artery stenting (CAS) using closed-cell design stent. Materials and Methods: Twelve unstable carotid plaque lesions diagnosed by magnetic resonance imaging were evaluated by OCT during CAS. Pre-procedural minimum lumen diameter and area were 1.5 ± 0.6 mm and 2.6 ± 1.6 mm2, respectively. The lesion was pre-dilated with balloon catheters (diameter 4.8 ± 0.3 mm), and closed-cell stent was deployed. PD was performed with balloon catheters of the same size ...

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    10. High-accurate and robust fingerprint anti-spoofing system using Optical Coherence Tomography

      High-accurate and robust fingerprint anti-spoofing system using Optical Coherence Tomography

      Traditional commercial automated fingerprint recognition systems (AFRSs) are vulnerable to fake attacks by the use of artificial fingerprints, due to its limitation on resolution and the difficulty of obtaining depth information. Developing new systems with strong anti-spoofing ability are of increasing concern in the current digital age. Inspired by the observation and comparison of fingertip skin structure and the one dimensional (1D) depth signals derived from OCT acquisition images between real finger and artificial fingerprints, two novel anti-spoofing features, namely depth-double-peak feature and sub-single-peak feature, were specifically defined. Depth-double-peak feature refers that there must be two and only two peaks ...

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    11. Retinal pathology on optical coherence tomography among eyes of older adults judged normal by color fundus photography

      Retinal pathology on optical coherence tomography among eyes of older adults judged normal by color fundus photography

      Purpose Optical coherence tomography (OCT) has revealed many details of retinal disease that were not available with older imaging technologies. In eyes of adults >60 years old with normal maculas as determined by color fundus photography (CFP) and a validated grading system, we screened for pathology using OCT. We also tested visual functions to assess potential impact of the observed pathologies on patients. Design cross-sectional study Participants This study recruited persons from primary ophthalmology care clinics. METHODS: CFP were assessed by the 9-step AREDS scale. OCT macular volumes of participants at step 1 on the AREDS scale, considered normal, were ...

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    12. Towards characterization of bacterial colonies and biofilms: an approach based on swept source optical coherence tomography

      Towards characterization of bacterial colonies and biofilms: an approach based on swept source optical coherence tomography

      The continuous development of microorganism colonies may lead to the development of biofilms. The ability to observe bacterial layers in real time using Optical Coherence Tomography (OCT) can be beneficial for cross-sectional growth studies of bacterial biofilms. A new mathematical model has been developed and utilized to calculate the backscattering optical properties of sample and estimate the necessary parameters. The spectroscopic based analytical method has been successfully demonstrated for characterization of different bacterial colonies and biofilms. The results were verified with conventional ‘Gram staining’ method. The proposed analytical method has potential to monitor realtime growth kinetics of bacteria. The quantities ...

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      Mentions: Raju Poddar
    13. Statistical evaluation method to determine the laser welding depth by optical coherence tomography

      Statistical evaluation method to determine the laser welding depth by optical coherence tomography

      A statistical filtering method to determine the depth of laser-welded seams from signals recorded by means of optical coherence tomography (OCT) is proposed and discussed. The measured data points are initially classified into noise and significant data by means of a noise probability, which was defined based on the normalized Poisson distribution. A percentile filter is then applied to the significant data to obtain the depth of the weld seam. It is shown that the depth determined by this approach corresponds to the real seam depth, as obtained from longitudinal sections, to within an average error of less than 5 ...

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    14. Possible Undiagnosed Glaucoma Detected by MultiColor Imaging of Retinal Diseases

      Possible Undiagnosed Glaucoma Detected by MultiColor Imaging of Retinal Diseases

      Purpose To evaluate for the presence of visible retinal nerve fiber layer (RNFL) defects consistent with undiagnosed glaucoma in MultiColor images (Heidelberg Engineering, Heidelberg, Germany) obtained at clinicians’ discretion for the diagnosis and management of retinal diseases. Design Retrospective chart review of MultiColor images obtained as part of routine clinical care between December 25, 2013 and June 24, 2014. Images were reviewed by 2 fellowship-trained glaucoma specialists (S.H.V.T., S.G.A.) for the presence of RNFL defects in the superotemporal or inferotemporal quadrants. No attention was given to the optic nerve head when identifying candidate images. Retinal ...

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    15. Retinal microvascular density on Optical Coherence Tomography Angiography and Osteoprotegerin serum levels in acute coronary syndrome patients

      Retinal microvascular density on Optical Coherence Tomography Angiography and Osteoprotegerin serum levels in acute coronary syndrome patients

      Introduction Optical Coherence Tomography - Angiography (OCT-A) is a quick and non-invasive exam performed to obtain a quantitative analysis of retinal microvascularisation . It is still unknown if this analysis reflects the systemic vascular status, and thus could be used as a screening tool for cardiovascular diseases . Osteoprotegerin is an atherosclerosis biomarker involved in the development of ischemic cardiovascular diseases. The aim of this study was to seek for a relation between Osteoprotegerin serum and retinal microvascularisation density through OCT-A in patients with a high cardiovascular risk profile. Materials and methods Patients hospitalized for an acute coronary syndrome in our University Hospital ...

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    16. Detection of Non-exudative Choroidal Neovascularization and Progression to Exudative Choroidal Neovascularization Using Optical Coherence Tomography Angiography

      Detection of Non-exudative Choroidal Neovascularization and Progression to Exudative Choroidal Neovascularization Using Optical Coherence Tomography Angiography

      Objective To detect non-exudative choroidal neovascularization (CNV) in age-related macular degeneration with optical coherence tomography angiography (OCTA) and determine risk of developing exudative CNV compared to eyes without non-exudative CNV. Design Prospective longitudinal observational study Participants Consecutive patients with drusen and pigmentary changes in the study eye and exudative neovascular AMD in the fellow eye. Methods Study participants underwent spectral domain OCTA (AngioVue, Optovue, Inc), clinical exam, and structural OCT at baseline and six-month intervals for two years. OCTA images were exported for custom processing to remove projection artifact and calculate CNV vessel area. Main Outcome Rate of developing exudation ...

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    17. COmbined multimodal analysis of Peripheral Retinal and mAcular circulation in Diabetic Retinopathy (COPRA Study)

      COmbined multimodal analysis of Peripheral Retinal and mAcular circulation in Diabetic Retinopathy (COPRA Study)

      Importance The relationship between peripheral retinal capillary non-perfusion with central NP is non-linear. Objective To systematically examine the relationships between the microvascular indices that are measured on OCTA and the presence and extent of peripheral non-perfusion in persons with diabetic retinopathy Design Retrospective cross-sectional study of patients with varying degrees of diabetic retinopathy ; Setting: Two large tertiary referral retina clinics Participants Eighty-two eyes of forty-five patients with varying degrees of diabetic retinopathy were enrolled and analyzed Main outcome Relationships between peripheral ischemia measured on FA and OCTA metrics, including FAZ and vessel density measurements. Results A significant decrease in mean ...

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    18. Ultra-widefield optical coherence tomographic imaging of posterior vitreous in eyes with high myopia

      Ultra-widefield optical coherence tomographic imaging of posterior vitreous in eyes with high myopia

      Purpose To investigate the morphological changes of posterior vitreous in highly myopic (HM) eyes of patients older than 50 years. Design Retrospective, observational case series. Methods Ultra-widefield swept-source OCT (UWF-OCT) examinations were performed on 768 eyes of 448 HM patients (50- to 89-years) and 54 eyes of 52 non-HM subjects with scan width of 23 mm and depth of 5 mm. HM was defined as an axial length longer than 26.5 mm. The area and morphology of the posterior vitreous detachments (PVDs) and adhesions onto retinal vessels were examined for 167 HM eyes and 11 non-HM eyes in which ...

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    19. Using intraoperative optical coherence tomography to image pediatric unilateral vocal fold paralysis

      Using intraoperative optical coherence tomography to image pediatric unilateral vocal fold paralysis

      Objectives Unilateral vocal fold paralysis (UVFP) impairs communication and reduces academic performance and social interactions in children. Deciding between temporary, permanent, or potentially destructive surgical interventions can be challenging, as there currently exists no reliable means of predicting vocal fold recovery or assessing the presence of vocal fold atrophy. Regarding vocal fold atrophy, optical coherence tomography (OCT) has been shown to be an appealing non-invasive alternative for accessing vocal fold structures. This study describes UVFP microanatomy and identifies possible vocal fold atrophy using OCT. Methods Three UVFP patients (ages 1, 11, and 17 years) underwent bilateral OCT imaging using a ...

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    20. Effect of Heart Rate on Early Progression of Cardiac Allograft Vasculopathy: A Prospective Study Using Highly Automated 3-D Optical Coherence Tomography Analysis

      Effect of Heart Rate on Early Progression of Cardiac Allograft Vasculopathy: A Prospective Study Using Highly Automated 3-D Optical Coherence Tomography Analysis

      Purpose Despite the controversial effect of elevated heart rate on progression of cardiac allograft vasculopathy (CAV), heart-rate-slowing agents are frequently prescribed with the assumption that higher heart rate predicts worse outcomes in cardiovascular disease. Methods This prospective 2-center trial investigated progression of CAV in 116 heart transplant (HTx) patients. Both baseline (1 month after HTx) and follow-up (12 months after HTx) examinations by coronary optical coherence tomography (OCT) were analyzed using highly automated 3D graph-based segmentation software. Mean heart rate was assessed by 24-hour ambulatory ECG monitoring at baseline and at 12-month follow-ups after HTx. Results During the first post-transplant ...

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    21. Techniques to Optimize the Use of Optical Coherence Tomography: Insights From the Manufacturer and User Facility Device Experience (MAUDE) Database

      Techniques to Optimize the Use of Optical Coherence Tomography: Insights From the Manufacturer and User Facility Device Experience (MAUDE) Database

      Background/Purpose Optical coherence tomography (OCT) is a high-resolution intravascular imaging modality used to assess coronary arteries and as an adjunctive tool for optimization of percutaneous coronary interventions. Overall, the rate of complications and adverse events related to intravascular imaging is low. Limited data exist on the most commonly reported complications and modes of failure related to the use of OCT. Therefore, we analyzed the post-marketing surveillance data from the Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) database to assess the reported complications and failure modes for OCT and reviewed techniques to optimize device use. Methods ...

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    22. Intra-operative point-of-procedure delineation of oral cancer margins using optical coherence tomography

      Intra-operative point-of-procedure delineation of oral cancer margins using optical coherence tomography

      Objectives Surgical margin status is a significant determinant of treatment outcome in oral cancer. Negative surgical margins can decrease the loco-regional recurrence by five-fold. The current standard of care of intraoperative clinical examination supplemented by histological frozen section, can result in a risk of positive margins from 5 to 17 percent. In this study, we attempted to assess the utility of intraoperative optical coherence tomography (OCT) imaging with automated diagnostic algorithm to improve on the current method of clinical evaluation of surgical margin in oral cancer. Materials and methods We have used a modified handheld OCT device with automated algorithm ...

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    23. Spontaneous Coronary Artery Dissection: Pathophysiological Insights From Optical Coherence Tomography

      Spontaneous Coronary Artery Dissection: Pathophysiological Insights From Optical Coherence Tomography

      Objectives This study used optical coherence tomography to investigate the mechanism of false lumen (FL) formation in spontaneous coronary artery dissection (SCAD) by studying: 1) differences between fenestrated and nonfenestrated SCAD; 2) vasa vasorum density; and 3) light attenuation characteristics of the FL. Background SCAD is an increasingly recognized cause of acute coronary syndromes , characterized by FL formation and compression of the true lumen (TL). The mechanisms underlying FL formation remain poorly understood. Methods A total of 65 SCAD patients (68 vessels) who underwent acute OCT imaging as part of routine clinical care were included. Images were classified by the ...

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