All Articles from David Huang -Optical Coherence Tomography News

Articles from David Huang

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1. Bulk motion subtraction in optical coherence tomography angiography
  
  Explore uspto.gov Mar 17 2020 Ophthalmology , Patents
  
  Described herein is an algorithm to remove decorrelation noise due to bulk motion in optical coherence tomography angiography (OCTA). OCTA B-frames are divided into segments within which the bulk motion velocity could be assumed constant. This velocity is recovered using linear regression of decorrelation versus the logarithm of reflectance in axial lines (A-lines) identified as bulk tissue by percentile analysis. The fitting parameters are used to calculate a reflectance-adjusted threshold for bulk motion decorrelation. Below this threshold, voxels are identified as non-flow tissue, and their flow values are set to zeros. Above this threshold, the voxels are identified as flow ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
2. Application of Corneal Optical Coherence Tomography Angiography for Assessment of Vessel Depth in Corneal Neovascularization
  
  Explore LWW Online Dec 28 2019 Ophthalmology
  
  Purpose: To map and measure the depths of corneal neovascularization (NV) using 3-dimensional optical coherence tomography angiography (OCTA) at 2 different wavelengths. Methods: Corneal NV of varying severity, distribution, and underlying etiology was examined. Average NV depth and vessel density were measured using 840-nm spectral-domain OCTA and 1050-nm swept-source OCTA. The OCTA results were compared with clinical slit-lamp estimation of NV depth. Results: Twelve eyes with corneal NV from 12 patients were imaged with OCTA. Clinically “superficial,” “midstromal,” and “deep” cases had an average vessel depth of 23%, 39%, and 66% on 1050-nm OCTA, respectively. Average vessel depth on OCTA ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto David Huang
3. Estimating Visual Field Mean Deviation using Optical Coherence Tomographic Nerve Fiber Layer Measurements in Glaucoma Patients
  
  Explore Nature Publishing Group Dec 10 2019 Ophthalmology
  
  To construct an optical coherence tomography (OCT) nerve fiber layer (NFL) parameter that has maximal correlation and agreement with visual field (VF) mean deviation (MD). The NFL_MD parameter in dB scale was calculated from the peripapillary NFL thickness profile nonlinear transformation and VF area-weighted averaging. From the Advanced Imaging for Glaucoma study, 245 normal, 420 pre-perimetric glaucoma (PPG), and 289 perimetric glaucoma (PG) eyes were selected. NFL_MD had significantly higher correlation (Pearson R: 0.68 vs 0.55, p < 0.001) with VF_MD than the overall NFL thickness. NFL_MD also had significantly higher sensitivity in detecting PPG (0.14 vs ...
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  Mentions: David Huang Joel S. Schuman Oregon Health & Science University
4. Sectorwise Visual Field Simulation Using Optical Coherence Tomographic Angiography Nerve Fiber Layer Plexus Measurements in Glaucoma
  
  Explore ScienceDirect Nov 29 2019 Ophthalmology
  
  Purpose To simulate 24-2 visual field (VF) using optical coherence tomographic angiography (OCTA) for glaucoma evaluation. Design Cross-sectional study. Methods One eye each of 39 glaucoma and 31 age-matched normal participants was scanned using 4.5-mm OCTA scans centered on the disc. The peripapillary retinal nerve fiber layer plexus capillary density (NFLP_CD, %area) was measured. The NFLP_CD and 24-2 VF maps were divided into 8 corresponding sectors using an extension of Garway-Heath scheme. Results Sector NFLP_CD was transformed to a logarithmic dB scale and converted to sector simulated VF deviation maps. Comparing simulated and actual 24-2 VF maps, the worst ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
5. Measuring Glaucomatous Focal Perfusion Loss in the Peripapillary Retina using Optical Coherence Tomographic Angiography
  
  Explore Ophthalmology Nov 12 2019 Ophthalmology
  
  Purpose To measure low perfusion areas (LPA) and focal perfusion loss (FPL) in the peripapillary retina using optical coherence tomographic angiography (OCTA) in glaucoma. Design Prospective observation study. Participants Forty-seven primary open angle glaucoma (POAG) patients and 36 normal subjects were analyzed. Methods One eye of each subject was scanned using AngioVue 4.5-mm OCTA scan centered on the disc. En face nerve fiber layer plexus angiogram was generated. Using custom software, capillary density map was obtained by computing the fraction of area occupied by flow pixels within each superpixel containing 21×21-pixels. The low-perfusion map is defined by local ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
6. The Bruno Lumbroso Lecture at the 7th International Congress on OCT Angiography
  
  Explore Optical Coherence Tomography News Oct 18 2019 Ophthalmology
  
  Dear Colleagues: As you know, the International Congress on OCT Angiography, En Face OCT and Advances in OCT that Professor Bruno Lumbroso initiated few years ago will be in its 7th Year this December 2019 in Rome. Certainly, this global Congress has become one of the most successful, most-attended, and most educational meetings in the field of retinal imaging. Every December during the past six years, more than 1,000 of us have enjoyed spending few days in Rome learning the latest advances in retinal imaging, from OCT to OCTA to adaptive optics to microperimetry, among others, and meeting new ...
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  Mentions: Philip J. Rosenfeld David Huang Oregon Health & Science University
7. Automated quantification of nonperfusion in the retina using optical coherence tomography angiography
  
  Explore uspto.gov Oct 1 2019 Ophthalmology , Patents
  
  Disclosed are methods and systems for measuring areas of nonperfusion in the retina using OCT imaging. The disclosed methods and systems allow for the automated segmentation and quantification of avascular areas of the retina utilizing information obtained from both structural OCT and OCT angiography (OCTA) data. The disclosed methods include filtering approaches which enhance vessel structure while suppressing noise, dynamic thresholding approaches to mitigate the detrimental effects of within-scan variability and low scan quality, and distance transform-based approaches to improve detection of ischemic regions. When combined with methods such as projection-resolved OCTA, the sensitivity to detect nonperfusion within different plexuses ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
8. Detecting and measuring areas of choriocapillaris low perfusion in intermediate, non-neovascular age-related macular degeneration
  
  Explore SPIE Digital Library Sep 17 2019 Ophthalmology
  
  Age-related macular degeneration (AMD) is a vision-threatening disease that affects the outer retina and choroid of elderly adults. Because photoreceptors are found in the outer retina and rely primarily on the trophic support of the underlying choriocapillaris, imaging of flow or lack thereof in choriocapillaris by optical coherence tomography angiography (OCTA) has great clinical potential in AMD assessment. We introduce a metric using OCTA, named “focal perfusion loss” (FPL) to describe the effects of age and non-neovascular AMD on choriocapillaris flow. Because OCTA imaging of choriocapillaris is vulnerable to artifacts—namely motion, projections, segmentation errors, and shadows—they are removed ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
9. Detection of reduced retinal vessel density in eyes with geographic atrophy secondary to age-related macular degeneration using projection-resolved optical coherence tomography angiography
  
  Explore American Journal of Ophthalmology Sep 14 2019 Ophthalmology
  
  Purpose To compare retinal vessel density in eyes with geographic atrophy (GA) secondary to age-related macular degeneration (AMD) to age-matched healthy eyes using projection-resolved optical coherence tomography angiography (PR-OCTA). Design Prospective cross-sectional study. Methods Study participants underwent macular 3×3-mm OCTA scans with spectral domain OCTA. Reflectance-compensated retinal vessel densities were calculated on projection-resolved superficial vascular complex (SVC), intermediate capillary plexus (ICP), and deep capillary plexus (DCP). Quantitative analysis using normalized deviation compared the retinal vessel density in GA regions, 500 μm GA rim regions, and non-GA regions to similar macular locations in control eyes. Results Ten eyes with GA ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
10. Automated segmentation of peripapillary retinal boundaries in OCT combining a convolutional neural network and a multi-weights graph search
  
  Explore OSA | OSA Publishing Aug 29 2019
  
  Quantitative analysis of the peripapillary retinal layers and capillary plexuses from optical coherence tomography (OCT) and OCT angiography images depend on two segmentation tasks – delineating the boundary of the optic disc and delineating the boundaries between retinal layers. Here, we present a method combining a neural network and graph search to perform these two tasks. A comparison of this novel method’s segmentation of the disc boundary showed good agreement with the ground truth, achieving an overall Dice similarity coefficient of 0.91 ± 0.04 in healthy and glaucomatous eyes. The absolute error of retinal layer boundaries segmentation in the ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
11. Monitoring retinal responses to acute intraocular pressure elevation in rats with visible light optical coherence tomography
  
  Explore SPIE Digital Library Jul 18 2019 Ophthalmology
  
  Elevated intraocular pressure (IOP) is an important risk factor for glaucoma. However, the role of IOP in glaucoma progression, as well as retinal physiology in general, remains incompletely understood. We demonstrate the use of visible light optical coherence tomography to measure retinal responses to acute IOP elevation in Brown Norway rats. We monitored retinal responses in reflectivity, angiography, blood flow, oxygen saturation (sO2 ), and oxygen metabolism over a range of IOP from 10 to 100 mmHg. As IOP was elevated, nerve fiber layer reflectivity was found to decrease. Vascular perfusion in the three retinal capillary plexuses remained steady until IOP ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
12. International Ocular Circulation Society Inaugural Meeting, August 10, 2019 Portland Oregon
  
  Explore Optical Coherence Tomography News Jul 11 2019 Ophthalmology
  
  The International Ocular Circulation Society (IOCS) was co-founded by a group of leading researchers in America, Asia, and Europe in 2018. The inaugural meeting of the new Society will be hosted by David Huang, M.D. and Yali Jia, Ph.D. of the Casey Eye Institute in Portland Oregon on August 10, 2019. The meeting will present 28 papers and 35 posters on technologies on the topics of imaging and measurement of ocular blood flow and oxygen metabolism, vascular anatomy and physiology, and the roles of ocular circulation in retina, optic nerve, neurological, and systemic diseases. The Oregon Health & Science ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
13. Projection-Resolved Optical Coherence Tomography Angiography of the Peripapillary Retina in Glaucoma
  
  Explore American Journal of Ophthalmology Jun 3 2019 Ophthalmology
  
  To detect plexus-specific peripapillary retinal perfusion defects in glaucoma using projection-resolved optical coherence tomography angiography (PR-OCTA).
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  Mentions: David Huang Oregon Health & Science University Yali Jia
14. Correlation of Outer Retinal Degeneration and Choriocapillaris Loss in Stargardt Disease Using En Face Optical Coherence Tomography and Optical Coherence Tomography Angiography
  
  Explore American Journal of Ophthalmology May 23 2019 Ophthalmology
  
  Purpose This study measured and correlated degeneration of the junction between the inner and outer segments (IS/OS), the retinal pigment epithelium (RPE), and the choriocapillaris (CC) in Stargardt disease (STGD). Design Prospective cross-sectional study. Methods This study was conducted at the Casey Eye Institute. A total of 23 patients with STGD were enrolled and underwent optical coherence tomography angiography (OCTA). Scans were centered on the fovea. OCT slab projections and en face boundary maps were used to create masks to measure total IS/OS loss or RPE atrophy as well as regions of isolated IS/OS loss, isolated RPE ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
15. Signal strength reduction effects in optical coherence tomographic angiography
  
  Explore Ophthalmology Retina May 11 2019 Ophthalmology
  
  Objective To elucidate the relationship between vessel density (VD) measurements and signal strength in optical coherence tomography angiography (OCTA). Design Cross-sectional study. Subjects: Healthy volunteers. Methods OCTA images obtained from healthy volunteers were analyzed to demonstrate the relationship between signal strength index (SSI) and VD. Experiments were performed to determine the effects of signal strength reduction on VD measurements on the Optovue/AngioVue and Cirrus/AngioPlex OCTA systems. Signal strength reduction was generated by either neutral density filters (NDF) or defocus. Main Outcome Measures Regression analysis of signal strength effects on VD. Results VD decreased linearly with signal strength with ...
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  Mentions: Optovue David Huang Oregon Health & Science University
16. Maximum value projection produces better en face OCT angiograms than mean value projection
  
  Explore OSA | OSA Publishing May 9 2019 Ophthalmology
  
  Optical coherence tomography angiography (OCTA) images rely on en face data projections for both qualitative and quantitative interpretation. Both maximum value and mean value projections are commonly used, and many researchers consider them essentially interchangeable approaches. On the contrary, we find that maximum value projection achieves a consistently higher signal-to-noise ratio and higher image contrast across multiple vascular layers, in both healthy eyes and for each disease examined.
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  Mentions: David Huang Oregon Health & Science University Yali Jia
17. Detection of Non-exudative Choroidal Neovascularization and Progression to Exudative Choroidal Neovascularization Using Optical Coherence Tomography Angiography
  
  Explore ScienceDirect Mar 26 2019 Ophthalmology
  
  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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  Mentions: Optovue David Huang Oregon Health & Science University
18. Real-time cross-sectional and en face OCT angiography guiding high-quality scan acquisition
  
  Explore OSA | OSA Publishing Mar 16 2019 Ophthalmology
  
  Defocusing, vignetting, and bulk motion degrade the image quality of optical coherence tomography angiography (OCTA) more significantly than structural OCT. The assessment of focus, alignment conditions, and stability of imaging subjects in commercially available OCTA systems are currently based on OCT signal quality alone, without knowledge of OCTA signal quality. This results in low yield rates for further quantification. In this Letter, we developed a novel OCTA platform based on a graphics processing unit (GPU) for a real-time, high refresh rate, B-san-by-B-scan split-spectrum amplitude-decorrelation angiography. The GPU provides a real-time display of both cross-sectional and en face images to assist ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
19. Visual Optics Postdoctoral/Research Fellow Opening at Oregon Health & Science University
  
  Explore Optical Coherence Tomography News Mar 14 2019 Ophthalmology , Jobs & Studentships
  
  A postdoctoral research fellow position is available in the Center for Ophthalmic Optics & Lasers Lab ( www.coollab.net ), Casey Eye Institute, Oregon Health & Science University. This is an outstanding opportunity for a candidate to use optical coherence tomography to conduct visual optics research in an academic ophthalmology setting. The researcher on this position will work with a team of scientists, engineers and physicians to develop ultrahigh-performance OCT systems for comprehensive optical characterization of the anterior eye and wide-field ocular surface topography, to improve post-refractive surgery intraocular lens power calculation, therapeutic scleral lens design, diagnosis and classification of corneal shape irregularities ...
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  Mentions: National Institutes of Health David Huang Oregon Health & Science University
20. DETECTION OF CLINICALLY UNSUSPECTED RETINAL NEOVASCULARIZATION WITH WIDE-FIELD OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY
  
  Explore LWW Online Mar 12 2019 Ophthalmology
  
  Purpose: To evaluate wide-field optical coherence tomography angiography (OCTA) for detection of clinically unsuspected neovascularization (NV) in diabetic retinopathy (DR). Methods: This prospective observational single-center study included adult patients with a clinical diagnosis of nonproliferative DR. Participants underwent a clinical examination, standard 7-field color photography, and OCTA with commercial and prototype swept-source devices. The wide-field OCTA was achieved by montaging five 6 × 10-mm scans from a prototype device into a 25 × 10-mm image and three 6 × 6-mm scans from a commercial device into a 15 × 6-mm image. A masked grader determined the retinopathy severity from color photographs. Two trained readers ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
21. Automated detection of shadow artifacts in optical coherence tomography angiography
  
  Explore OSA | OSA Publishing Mar 1 2019 Ophthalmology
  
  Frequently, when imaging retinal vasculature with optical coherence tomography angiography (OCTA) in diseased eyes, there are unavoidable obstacles to the propagation of light such as vitreous floaters or the pupil boundary. These obstacles can block the optical coherence tomography (OCT) beam and impede the visualization of the underlying retinal microcirculation. Detecting these shadow artifacts is especially important in the quantification of metrics that assess retinal disease progression because they might masquerade as regional perfusion loss. In this work, we present an algorithm to identify shadowed areas in OCTA of healthy subjects as well as patients with diabetic retinopathy, uveitis and ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
22. Systems and methods for retinal layer segmentation in OCT imaging and OCT angiography
  
  Explore uspto.gov Nov 13 2018 Ophthalmology , Patents
  
  Disclosed herein are methods and systems for segmenting, visualizing, and quantifying the layered structure of retina in optical coherence tomography datasets. The disclosed methods have particular application to OCT angiography data, where specific retina layers have distinct vascular structures and characteristics that can be altered in various pathological conditions of the eye.
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  Mentions: David Huang Oregon Health & Science University Yali Jia
23. Rodent retinal circulation organization and oxygen metabolism revealed by visible-light optical coherence tomography
  
  Explore OSA | OSA Publishing Nov 3 2018 Ophthalmology
  
  Visible light optical coherence tomography (vis-OCT) is an emerging label-free and high-resolution 3-dimensional imaging technique that can provide retinal oximetry, angiography, and flowmetry in one modality. In this paper, we studied the organization of the arterial and venous retinal circulation in rats using vis-OCT. Arterioles were found predominantly in the superficial vascular plexus whereas veins tended to drain capillaries from the deep capillary plexus. After that, we determined the oxygen metabolic rate supported by retinal microcirculation by combining retinal vessel oxygen saturation and blood flow measurements. The ability to visualize and monitor retinal circulation organization and oxygen metabolism by vis-OCT ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
24. Quantitative evaluation of retinal artery occlusion using optical coherence tomography angiography: A case report
  
  Explore LWW Online Oct 9 2018 Ophthalmology
  
  Rationale: Retinal artery occlusion (RAO) results in painless, catastrophic vision loss in a period of seconds. Optical coherence tomography angiography (OCTA) can image retinal microcirculation, which is helpful to evaluate treatment response during the follow-up period. Using a single case with central RAO, we report its retinal perfusion changes before and after treatment using OCTA. Patient concerns: A 36-year-old Chinese man came to our clinic with a sudden, painless loss of vision (hand motion) in his left eye. A vasodilator (nicotinic acid) was used as the primary treatment. OCTA imaging and a visual field examination were performed to assess the ...
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  Mentions: David Huang Oregon Health & Science University Yali Jia
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