All Articles from Sina Farsiu -Optical Coherence Tomography News

Articles from Sina Farsiu

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1. Deep learning-based single-shot prediction of differential effects of anti-VEGF treatment in patients with diabetic macular edema
  
  Explore OSA | OSA Publishing Jan 28 2020 Ophthalmology
  
  Anti-vascular endothelial growth factor (VEGF) agents are widely regarded as the first line of therapy for diabetic macular edema (DME) but are not universally effective. An automatic method that can predict whether a patient is likely to respond to anti-VEGF therapy can avoid unnecessary trial and error treatment strategies and promote the selection of more effective first-line therapies. The objective of this study is to automatically predict the efficacy of anti-VEGF treatment of DME in individual patients based on optical coherence tomography (OCT) images. We performed a retrospective study of 127 subjects treated for DME with three consecutive injections of ...
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  Mentions: Duke University Sina Farsiu
2. Beyond Performance Metrics: Automatic Deep Learning Retinal OCT Analysis Reproduces Clinical Trial Outcome
  
  Explore ScienceDirect Dec 28 2019 Ophthalmology
  
  Purpose To validate the efficacy of a fully-automatic, deep learning-based segmentation algorithm beyond conventional performance metrics by measuring the primary outcome of a clinical trial for macular telangiectasia type 2 (MacTel2) Design Evaluation of diagnostic test or technology Participants 92 eyes from 62 participants with MacTel2 from a phase 2 clinical trial (NCT01949324) randomized to one of two treatment groups Methods The ellipsoid zone (EZ) defect areas were measured on spectral domain optical coherence tomography images of each eye at two time points (Baseline and Month 24) by a fully-automatic, deep learning-based segmentation algorithm. The change in EZ defect area ...
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  Mentions: Duke University Sina Farsiu
3. Special Section Guest Editorial: Advances in Retinal Imaging
  
  Explore SPIE Digital Library Dec 12 2019 Ophthalmology
  
  The guest editorial provides an introduction to the Special Section on Advanced Retinal Imaging: Instrumentation, Methods, and Applications. The retina is a peripheral part of the central nerve system (CNS) and shares many similarities with the cerebral cortex. They both have layered anatomy, the same types of functional elements and neurotransmitters, and similar vascular organization and blood-tissue barriers. With far fewer neuronal cell types and simpler anatomical structures, the retina is an excellent target for studying neural circuitry and neurovascular coupling. Meanwhile, approximately 80 percent of information from the outside world is processed as visual perception, 1 and retina-related blindness ...
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  Mentions: Duke University Stanford University Boston University
4. Optical coherence refraction tomography
  
  Explore Nature Publishing Group Aug 21 2019
  
  $Optical coherence refraction tomography$
  Optical coherence tomography (OCT) is a cross-sectional, micrometre-scale imaging modality with widespread clinical application. Typical OCT systems sacrifice lateral resolution to achieve long depths of focus for bulk tissue imaging, and therefore tend to have better axial than lateral resolution. Such anisotropic resolution can obscure fine ultrastructural features. Furthermore, conventional OCT suffers from refraction-induced image distortions. Here, we introduce optical coherence refraction tomography (OCRT), which extends the superior axial resolution to the lateral dimension, synthesizing undistorted cross-sectional image reconstructions from multiple conventional images acquired with angular diversity. In correcting refraction-induced distortions to register the OCT images, OCRT also achieves spatially ...
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  Mentions: Joseph A. Izatt Duke University Sina Farsiu
5. Postdoctoral Associate Position at Duke Vision and Image Processing Laboratory
  
  Explore Optical Coherence Tomography News Aug 15 2019 Jobs & Studentships
  
  Immediate opening at Duke University Biomedical Engineering Department for a postdoc interested in interdisciplinary applications of image analysis and computer vision with emphasis on optical coherence tomography image analysis. Postdoc will be supervised by Prof. Sina Farsiu ( http://people.duke.edu/~sf59/ ). The candidate must have a demonstrated strong background in image processing as evidenced by publication of papers in high-impact peer-reviewed journals. Programming skill in MATLAB/Python is required. PhD in EE, BME, or CS. Prior experience in ophthalmic sciences, optical coherence tomography, adaptive optics is a plus but not necessary. Projects can be chosen based on the interests ...
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  Mentions: Duke University Sina Farsiu
6. Deep longitudinal transfer learning-based automatic segmentation of photoreceptor ellipsoid zone defects on optical coherence tomography images of macular telangiectasia type 2
  
  Explore OSA | OSA Publishing May 22 2018 Ophthalmology
  
  Photoreceptor ellipsoid zone (EZ) defects visible on optical coherence tomography (OCT) are important imaging biomarkers for the onset and progression of macular diseases. As such, accurate quantification of EZ defects is paramount to monitor disease progression and treatment efficacy over time. We developed and trained a novel deep learning-based method called Deep OCT Atrophy Detection (DOCTAD) to automatically segment EZ defect areas by classifying 3-dimensional A-scan clusters as normal or defective. Furthermore, we introduce a longitudinal transfer learning paradigm in which the algorithm learns from segmentation errors on images obtained at one time point to segment subsequent images with higher ...
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  Mentions: Duke University Sina Farsiu
7. Comparison of chorioretinal layers in rhesus macaques using spectral-domain optical coherence tomography and high-resolution histological sections
  
  Explore ScienceDirect Jan 21 2018 Ophthalmology
  
  Nonhuman primates are important preclinical models of retinal diseases because they uniquely possess a macula similar to humans. Ocular imaging technologies such as spectral-domain optical coherence tomography (SD-OCT) allow noninvasive, in vivo measurements of chorioretinal layers with near-histological resolution. However, the boundaries are based on differences in reflectivity, and detailed correlations with histological tissue layers have not been explored in rhesus macaques, which are widely used for biomedical research. Here, we compare the macular anatomy and thickness measurements of chorioretinal layers in rhesus macaque eyes using SD-OCT and high-resolution histological sections. Images were obtained from methylmethacrylate-embedded histological sections of 6 ...
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  Mentions: Duke University UC Davis Sina Farsiu
8. Statistical Models of Signal and Noise and Fundamental Limits of Segmentation Accuracy in Retinal Optical Coherence Tomography
  
  Explore IEEE Xplore Nov 18 2017 Ophthalmology
  
  Optical coherence tomography (OCT) has revolutionized diagnosis and prognosis of ophthalmic diseases by visualization and measurement of retinal layers. To speed up quantitative analysis of disease biomarkers, an increasing number of automatic segmentation algorithms have been proposed to estimate the boundary locations of retinal layers. While the performance of these algorithms has significantly improved in recent years, a critical question to ask is how far we are from a theoretical limit to OCT segmentation performance. In this paper, we present the Cramèr-Rao lower bounds (CRLBs) for the problem of OCT layer segmentation. In deriving the CRLBs, we address the ...
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  Mentions: Joseph A. Izatt Duke University Sina Farsiu
9. Characterization of Long Working Distance Optical Coherence Tomography for Imaging of Pediatric Retinal Pathology
  
  Explore TVST Journal Oct 22 2017 Ophthalmology
  
  Purpose : We determined the feasibility of fovea and optic nerve head imaging with a long working distance (LWD) swept source optical coherence tomography (OCT) prototype in adults, teenagers, and young children. Methods : A prototype swept source OCT system with a LWD (defined as distance from the last optical element of the imaging system to the eye) of 350 mm with custom fixation targets was developed to facilitate imaging of children. Imaging was performed in 49 participants from three age groups: 26 adults, 16 children 13 to 18 years old (teenagers), and seven children under 6 years old (young children) under ...
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  Mentions: Joseph A. Izatt Duke University Cynthia A. Toth
10. Macular fluid reduces reproducibility of choroidal thickness measurements on enhanced depth optical coherence tomography
  
  Explore American Journal of Ophthalmology Oct 13 2017 Ophthalmology
  
  Purpose To determine if different types of retinal fluid in the central macula affect the reproducibility of choroidal thickness (CT) measurements on enhanced depth imaging optical coherence tomography (EDI-OCT) Design retrospective, reliability analysis Methods EDI-OCT images were obtained and the choroidal-scleral junction was analyzed through semi-automated segmentation. CT was measured at the fovea and averaged across the central 3 mm horizontal segment. Demographic data, central macular thickness and type of fluid present were recorded. Intragrader and intergrader repeatability were assessed using the intraclass correlation coefficient (ICC) and coefficient of repeatability (CR). Results Of 124 eyes analyzed, 60 (48.4%) had ...
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  Mentions: Duke University UC Davis Sina Farsiu
11. Correlation Between Macular Integrity Assessment and Optical Coherence Tomography Imaging of Ellipsoid Zone in Macular Telangiectasia Type 2
  
  Explore IOVS Journal Oct 4 2017 Ophthalmology
  
  Purpose : To correlate ellipsoid zone (EZ) defects on spectral-domain optical coherence tomography (SD-OCT) with retinal sensitivity loss on macular integrity assessment (MAIA) microperimetry in macular telangiectasia type 2 (MacTel). Methods : Macular SD-OCT volumes and microperimetry maps were obtained during the international, multicenter, randomized phase 2 trial of ciliary neurotrophic factor for type 2 MacTel on two visits within 5 days of one another. Software was developed to register SD-OCT to MAIA scanning laser ophthalmoscopy images and to overlay EZ defect areas on the microperimetry maps generated from microperimetry sensitivity values at specific points and from interpolated sensitivity values. A total ...
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  Mentions: Duke University Sina Farsiu
12. Retinal imaging in human autopsy eyes using a custom optical coherence tomography periscope
  
  Explore OSA | OSA Publishing Sep 2 2017
  
  Age-related macular degeneration (AMD) is a major cause of vision loss in the elderly. To better study the pathobiology of AMD, postmortem eyes offer an excellent opportunity to correlate optical coherence tomography (OCT) imaging characteristics with histopathology. However, postmortem eyes from autopsy present challenges to standard OCT imaging including opaque anterior segment structures and standard of care autopsy processing resulting in oblique views to the macula. To overcome these challenges, we report a custom periscope attached by a standard mount to an OCT sample arm and demonstrate high quality macular OCT acquisitions in autopsy-processed eyes.
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  Mentions: Joseph A. Izatt Duke University Sina Farsiu
13. Optical Coherence Tomography Predictors of Risk for Progression to Non-Neovascular Atrophic Age-Related Macular Degeneration
  
  Explore Ophthalmology Aug 25 2017 Ophthalmology
  
  Purpose Appearance of geographic atrophy (GA) on color photography (CP) is preceded by specific features on spectral-domain optical coherence tomography (SD OCT). We aimed to build SD OCT–based risk assessment models for 5-year new onset of GA and central GA on CP. Design Prospective, longitudinal study. Participants Age-Related Eye Disease Study 2 Ancillary SD OCT study participants with age-related macular degeneration (AMD) with bilateral large drusen or noncentral GA and at least 1 eye without advanced disease (n = 317). Methods For 1 eye per participant, qualitative and quantitative SD OCT variables were derived from standardized grading and semiautomated segmentation ...
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  Mentions: Duke University Cynthia A. Toth Sina Farsiu
14. Automatic segmentation of nine retinal layer boundaries in OCT images of non-exudative AMD patients using deep learning and graph search
  
  Explore OSA | OSA Publishing Jul 1 2017 Ophthalmology
  
  We present a novel framework combining convolutional neural networks (CNN) and graph search methods (termed as CNN-GS) for the automatic segmentation of nine layer boundaries on retinal optical coherence tomography (OCT) images. CNN-GS first utilizes a CNN to extract features of specific retinal layer boundaries and train a corresponding classifier to delineate a pilot estimate of the eight layers. Next, a graph search method uses the probability maps created from the CNN to find the final boundaries. We validated our proposed method on 60 volumes (2915 B-scans) from 20 human eyes with non-exudative age-related macular degeneration (AMD), which attested to ...
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  Mentions: Duke University Sina Farsiu University of Melbourne
15. Enhanced visualization of peripheral retinal vasculature with wavefront sensorless adaptive optics optical coherence tomography angiography in diabetic patients
  
  Explore OSA | OSA Publishing Dec 20 2016 Ophthalmology
  
  Optical coherence tomography angiography (OCTA) is a promising technique for non-invasive visualization of vessel networks in the human eye. We debut a system capable of acquiring wide field-of-view ( > 70 ° >70° ) OCT angiograms without mosaicking. Additionally, we report on enhancing the visualization of peripheral microvasculature using wavefront sensorless adaptive optics (WSAO). We employed a fast WSAO algorithm that enabled wavefront correction in < 2 s <2 s by iterating the mirror shape at the speed of OCT B-scans rather than volumes. Also, we contrasted ∼ 7 ° ∼7° field-of-view OCTA angiograms acquired in the periphery with and without WSAO correction. On average, WSAO improved ...
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  Mentions: Joseph A. Izatt Duke University Sina Farsiu
16. Wide-field retinal optical coherence tomography with wavefront sensorless adaptive optics for enhanced imaging of targeted regions
  
  Explore OSA | OSA Publishing Dec 3 2016 Ophthalmology
  
  The peripheral retina of the human eye offers a unique opportunity for assessment and monitoring of ocular diseases. We have developed a novel wide-field (>70°) optical coherence tomography system (WF-OCT) equipped with wavefront sensorless adaptive optics (WSAO) for enhancing the visualization of smaller (<25°) targeted regions in the peripheral retina. We iterated the WSAO algorithm at the speed of individual OCT B-scans (~20 ms) by using raw spectral interferograms to calculate the optimization metric. Our WSAO approach with a 3 mm beam diameter permitted primarily low- but also high- order peripheral wavefront correction in less than 10 seconds. In preliminary ...
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  Mentions: Joseph A. Izatt Duke University Sina Farsiu
17. Segmentation guided registration of wide field-of-view retinal optical coherence tomography volumes
  
  Explore OSA | OSA Publishing Nov 1 2016 Ophthalmology
  
  Patient motion artifacts are often visible in densely sampled or large wide field-of-view (FOV) retinal optical coherence tomography (OCT) volumes. A popular strategy for reducing motion artifacts is to capture two orthogonally oriented volumetric scans. However, due to larger volume sizes, longer acquisition times, and corresponding larger motion artifacts, the registration of wide FOV scans remains a challenging problem. In particular, gaps in data acquisition due to eye motion, such as saccades, can be significant and their modeling becomes critical for successful registration. In this article, we develop a complete computational pipeline for the automatic motion correction and accurate registration ...
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  Mentions: Duke University Sina Farsiu Anthony N. Kuo
18. Needle Depth and Big-Bubble Success in Deep Anterior Lamellar Keratoplasty: An Ex Vivo Microscope-Integrated OCT Study
  
  Explore LWW Online Oct 7 2016 Ophthalmology
  
  Purpose: To examine big-bubble (BB) formation success rates in deep anterior lamellar keratoplasty (DALK) at various corneal depths using real-time guidance from swept-source, microscope-integrated optical coherence tomography (SS-MIOCT). Methods: The DALK procedure was performed ex vivo with 34 human donor corneoscleral buttons on pressurized artificial anterior chambers using the BB technique employed by Anwar and Teichmann. We inserted a needle under controlled ex vivo conditions to corneal depths ranging from 40% to ≥90% using real-time guidance from SS-MIOCT and injected air. BB success was then determined for each injection. Results: The average needle depth for successful full BB formation was ...
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  Mentions: Joseph A. Izatt Duke University Cynthia A. Toth
19. Segmentation Based Sparse Reconstruction of Optical Coherence Tomography Images
  
  Explore IEEE Xplore Sep 27 2016 Ophthalmology
  
  We demonstrate the usefulness of utilizing a segmentation step for improving the performance of sparsity based image reconstruction algorithms. In specific, we will focus on retinal optical coherence tomography (OCT) reconstruction and propose a novel segmentation based reconstruction framework with sparse representation, termed segmentation based sparse reconstruction (SSR). The SSR method uses automatically segmented retinal layer information to construct layer-specific structural dictionaries. In addition, the SSR method efficiently exploits patch similarities within each segmented layer to enhance the reconstruction performance. Our experimental results on clinical-grade retinal OCT images demonstrate the effectiveness and efficiency of the proposed SSR method for both ...
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  Mentions: Duke University Sina Farsiu
20. Length-adaptive graph search for automatic segmentation of pathological features in optical coherence tomography images
  
  Explore SPIE | Journal Aug 2 2016 Ophthalmology
  
  We introduce a metric in graph search and demonstrate its application for segmenting retinal optical coherence tomography (OCT) images of macular pathology. Our proposed “adjusted mean arc length” (AMAL) metric is an adaptation of the lowest mean arc length search technique for automated OCT segmentation. We compare this method to Dijkstra’s shortest path algorithm, which we utilized previously in our popular graph theory and dynamic programming segmentation technique. As an illustrative example, we show that AMAL-based length-adaptive segmentation outperforms the shortest path in delineating the retina/vitreous boundary of patients with full-thickness macular holes when compared with expert manual ...
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  Mentions: Joseph A. Izatt Duke University Sina Farsiu
21. Impact of Microscope-Integrated OCT on Ophthalmology Resident Performance of Anterior Segment Surgical Maneuvers in Model Eyes
  
  Explore IOVS Journal Jul 14 2016 Ophthalmology
  
  Purpose : The integration of swept-source optical coherence tomography (SS-OCT) into the operating microscope enables real-time, tissue-level three-dimensional (3D) imaging to aid in ophthalmic microsurgery. In this prospective randomized controlled study, we evaluated the impact of SS microscope-integrated OCT (MI-OCT) on ophthalmology residents' performance of ophthalmic microsurgical maneuvers. Methods : Fourteen ophthalmology residents from a single institution were stratified by year of training and randomized to perform four anterior segment surgical maneuvers on porcine eyes with (MI-OCT+) or without (MI-OCT−) direct intraoperative OCT guidance. Subsequently, both groups repeated the same maneuvers without MI-OCT feedback to test whether initial MI-OCT experience affected subsequent ...
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  Mentions: Joseph A. Izatt Duke University Cynthia A. Toth
22. Posterior Eye Shape Measurement With Retinal OCT Compared to MRI
  
  Explore IOVS Journal Jul 14 2016 Ophthalmology
  
  Purpose : Posterior eye shape assessment by magnetic resonance imaging (MRI) is used to study myopia. We tested the hypothesis that optical coherence tomography (OCT), as an alternative, could measure posterior eye shape similarly to MRI. Methods : Macular spectral-domain OCT and brain MRI images previously acquired as part of the Singapore Epidemiology of Eye Diseases study were analyzed. The right eye in the MRI and OCT images was automatically segmented. Optical coherence tomography segmentations were corrected for optical and display distortions requiring biometry data. The segmentations were fitted to spheres and ellipsoids to obtain the posterior eye radius of curvature ( R ...
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  Mentions: Joseph A. Izatt Duke University Sina Farsiu
23. Repeatability of Choroidal Thickness Measurements on Enhanced Depth Imaging OCT using Different Posterior Boundaries
  
  Explore American Journal of Ophthalmology Jun 23 2016 Ophthalmology
  
  Purpose To assess the reliability of manual choroidal thickness measurements by comparing different posterior boundary definitions of the choroidal-scleral junction on enhanced depth imaging optical coherence tomography (EDI-OCT). Design Reliability analysis Methods Two graders marked the choroidal-scleral junction with segmentation software using different posterior boundaries: 1) the outer border of the choroidal vessel lumen, 2) the outer border of the choroid stroma, and 3) the inner border of the sclera, to measure the vascular choroidal thickness (VCT), stromal choroidal thickness (SCT), and total choroidal thickness (TCT), respectively. Measurements were taken at 0.5 mm intervals from 1.5 mm nasal ...
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  Mentions: Duke University Sina Farsiu
24. Postdoctoral Research Fellowship in Clinical Applications of Image Processing at Duke University
  
  Explore Optical Coherence Tomography News May 19 2016 Jobs & Studentships
  
  Immediate opening at Duke University Biomedical Engineering Department for a Postdoctoral Research Associate interested in interdisciplinary applications of image analysis and computer vision with emphasis on applications in Optical Coherence Tomography (OCT) and adaptive optics (AO) imaging. Postdoc will be supervised by Prof. Sina Farsiu ( http://people.duke.edu/~sf59/ ) in collaboration with Prof. Joseph A. Izatt ( http://bme.duke.edu/faculty/joseph-izatt ) and other senior professors from Duke University School of Medicine. The candidate must have a demonstrated strong background in image processing as evidenced by publication of papers in high-impact peer-reviewed journals. Programming skill in MATLAB is required ...
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  Mentions: Joseph A. Izatt Duke University Sina Farsiu
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