1. Articles from Nadia K. Waheed

    1-24 of 84 1 2 3 4 »
    1. A practical guide to optical coherence tomography angiography interpretation

      A practical guide to optical coherence tomography angiography interpretation

      Background Optical coherence tomography angiography (OCTA) can image the retinal vasculature in vivo, without the need for contrast dye. This technology has been commercially available since 2014, however, much of its use has been limited to the research setting. Over time, more clinical practices have adopted OCTA imaging. While countless publications detail OCTA’s use for the study of retinal microvasculature, few studies outline OCTA’s clinical utility. Body This review provides an overview of OCTA imaging and details tips for successful interpretation. The review begins with a summary of OCTA technology and artifacts that arise from image acquisition. New ...

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    2. Maximum A Posteriori Signal Recovery for Optical Coherence Tomography Angiography Image Generation and Denoising

      Maximum A Posteriori Signal Recovery for Optical Coherence Tomography Angiography Image Generation and Denoising

      Optical coherence tomography angiography (OCTA) is a novel and clinically promising imaging modality to image retinal and sub-retinal vasculature. Based on repeated optical coherence tomography (OCT) scans, intensity changes are observed over time and used to compute OCTA image data. OCTA data are prone to noise and artifacts caused by variations in flow speed and patientmovement. We propose a novel iterativemaximuma posteriori signal recovery algorithm in order to generate OCTA volumes with reduced noise and increased image quality. This algorithm is based on previous work on probabilistic OCTA signal models and maximum likelihood estimates. Reconstruction results using total variation minimization ...

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    3. Choroidal nonperfusion on optical coherence tomography angiography in a case of unilateral posterior segment ocular sarcoidosis misdiagnosed as MEWDS

      Choroidal nonperfusion on optical coherence tomography angiography in a case of unilateral posterior segment ocular sarcoidosis misdiagnosed as MEWDS

      Purpose To report a case of presumed ocular sarcoidosis initially presenting with features of multiple evanescent white dot syndrome (MEWDS) with atypical optical coherence tomography angiography (OCTA) findings. Observations A 23 year-old woman presented with a unilateral central scotoma, photophobia, and decreased visual acuity after a viral illness. Examination of the right eye revealed multiple round white macular spots and stippled granularity at the fovea. Multimodal imaging with fluorescein angiography (FA), indocyanine green angiography (ICG), fundus autofluorescence (FAF), and optical coherence tomography (OCT) was consistent with a diagnosis of MEWDS. However, OCTA demonstrated choriocapillaris (CC) flow deficits, which is not ...

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    4. Anterior-segment spectral domain optical coherence tomography in epidermolysis bullosa

      Anterior-segment spectral domain optical coherence tomography in epidermolysis bullosa

      Purpose Assess epidermolysis bullosa (EB)-related corneal pathology using anterior segment optical coherence tomography (AS-OCT) and correlate imaging with clinical metrics in EB patients versus age-matched controls. Methods EB patients and controls were recruited during an EB conference (July 2018) and at Tufts Medical Center (June–August 2019). Subjects completed a questionnaire, had best corrected visual acuity (BCVA) tested, and underwent AS-OCT scanning. Stromal and epithelial thickness were measured. Depth, length, and type of the three largest lesions were assessed by a masked examiner using a novel pathology grading system. Multivariate analysis of AS-OCT findings and clinical metrics was performed ...

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    5. Repeatability of binarization thresholding methods for optical coherence tomography angiography image quantification

      Repeatability of binarization thresholding methods for optical coherence tomography angiography image quantification

      Binarization is a critical step in analysis of retinal optical coherence tomography angiography (OCTA) images, but the repeatability of metrics produced from various binarization methods has not been fully assessed. This study set out to examine the repeatability of OCTA quantification metrics produced using different binarization thresholding methods, all of which have been applied in previous studies, across multiple devices and plexuses. Successive 3 × 3 mm foveal OCTA images of 13 healthy eyes were obtained on three different devices. For each image, contrast adjustments, 3 image processing techniques (linear registration, histogram normalization, and contrast-limited adaptive histogram equalization), and 11 binarization ...

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    6. Using the Pathophysiology of Dry AMD to Guide Binarization of the Choriocapillaris on OCTA: A Model

      Using the Pathophysiology of Dry AMD to Guide Binarization of the Choriocapillaris on OCTA: A Model

      Especially since the incorporation of swept laser sources, optical coherence tomography angiography (OCTA) has enabled quantification of choriocapillaris perfusion. A critical step in this process is binarization, which makes angiographic images quantifiable in terms of perfusion metrics. It remains challenging to have confidence that choriocapillaris perfusion metrics reflect the reality of pathophysiologic flow, largely because choice of binarization method can result in significantly different perfusion metric outcomes. This commentary discusses a proof-of-concept case involving comparative assessment of binarization methods for a set of dry age-related macular degeneration OCTA data. One of these methods was deemed preferable based on superior agreement ...

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    7. The long-term effects of anti-vascular endothelial growth factor therapy on the optical coherence tomography angiographic appearance of neovascularization in age-related macular degeneration

      The long-term effects of anti-vascular endothelial growth factor therapy on the optical coherence tomography angiographic appearance of neovascularization in age-related macular degeneration

      Background The short-term effects of anti-vascular endothelial growth factor (anti-VEGF) treatment on macular neovascularization (MNV) morphology is well described, but long-term studies on morphologic changes and correlation of such changes to the type of MNV have not been conducted. This study aims to determine if different types of MNVs in neovascular AMD (nAMD) behave differently with anti-VEGF treatment as visualized on optical coherence tomography angiography (OCTA). Methods Treatment-naïve nAMD patients were retrospectively screened for baseline and follow-up OCTA imaging 10 or more months after initial treatment. Images were graded for MNV type, area, activity, mature versus immature vessels, vessel ...

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    8. High-Speed, Ultrahigh-Resolution Spectral-Domain OCT with Extended Imaging Range Using Reference Arm Length Matching

      High-Speed, Ultrahigh-Resolution Spectral-Domain OCT with Extended Imaging Range Using Reference Arm Length Matching

      Purpose : To develop high-speed, extended-range, ultrahigh-resolution spectral-domain optical coherence tomography (UHR SD-OCT) and demonstrate scan protocols for clinical retinal imaging. Methods : A UHR SD-OCT operating at 840-nm with 150-nm bandwidths was developed. The axial imaging range was extended by dynamically matching reference arm length to the retinal contour during acquisition. Two scan protocols were demonstrated for imaging healthy participants and patients with dry age-related macular degeneration. A high-definition raster protocol with intra–B-scan reference arm length matching (ReALM) was used for high-quality cross-sectional imaging. A cube volume scan using horizontal and vertical rasters with inter–B-scan ReALM and software motion ...

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    9. Model-to-Data Approach for Deep Learning in Optical Coherence Tomography Intraretinal Fluid Segmentation

      Model-to-Data Approach for Deep Learning in Optical Coherence Tomography Intraretinal Fluid Segmentation

      Importance Amid an explosion of interest in deep learning in medicine, including within ophthalmology, concerns regarding data privacy, security, and sharing are of increasing importance. A model-to-data approach, in which the model itself is transferred rather than data, can circumvent many of these challenges but has not been previously demonstrated in ophthalmology. Objective To determine whether a model-to-data deep learning approach (ie, validation of the algorithm without any data transfer) can be applied in ophthalmology. Design, Setting, and Participants This single-center cross-sectional study included patients with active exudative age-related macular degeneration undergoing optical coherence tomography (OCT) at the New England ...

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    10. Concerns about the interpretation of OCT and fundus findings in COVID-19 patients in recent Lancet publication

      Concerns about the interpretation of OCT and fundus findings in COVID-19 patients in recent Lancet publication

      We read with great interest the correspondence in Lancet by Marinho et al. [ 1 ] describing purported retinal manifestations of coronavirus disease (COVID-19). While there is great interest to understand potential ocular complications of COVID-19 during this pandemic, we have some concerns regarding the interpretation of the fundus and optical coherence tomography (OCT) findings. Marinho et al. examined 12 COVID-19 patients (all confirmed by PCR or antibody testing) with typical systemic disease but no visual symptoms. The reported cohort was relatively young (25–69 years; no mean or median provided) without severe systemic disease, although 2 were hospitalized. Eleven of the ...

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    11. 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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    12. Macular and Peripapillary OCTA Metrics Predict Progression in Diabetic Retinopathy: A Sub-analysis of TIME-2b Study Data

      Macular and Peripapillary OCTA Metrics Predict Progression in Diabetic Retinopathy: A Sub-analysis of TIME-2b Study Data

      Purpose To identify optical coherence tomography angiography (OCTA) derived vessel metrics of the macula and optic nerve head (ONH) that predict diabetic retinopathy (DR) disease progression. Design Secondary analysis of clinical trial data Methods This was a sub-analysis of prospectively collected data from 73 subjects that participated in the TIME-2b Study (Aerpio Pharmaceuticals), a multi-center clinical trial for patients with moderate to severe DR treated with AKB-9778 and followed over a 12-month period. Eligible subjects were tested every 3 months with color fundus photography, spectral domain OCT and slit-lamp biomicroscopy. OCTA of the macula and ONH was obtained for a ...

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    13. Morphological changes in intraretinal microvascular abnormalities after anti-VEGF therapy visualized on optical coherence tomography angiography

      Morphological changes in intraretinal microvascular abnormalities after anti-VEGF therapy visualized on optical coherence tomography angiography

      Background To examine the baseline morphological characteristics and alterations in intraretinal microvascular abnormalities (IRMAs) in response to anti-vascular endothelial growth factor (anti-VEGF) treatment, documented by optical coherence tomography angiography (OCTA) in diabetic eyes. Methods In this retrospective study, IRMAs were evaluated with multimodal imaging (fundus photography, fluorescein angiography, OCTA) in treatment-naïve diabetic eyes before and after anti-VEGF treatment for diabetic macular edema (DME) and/or proliferative diabetic retinopathy (PDR) and compared to diabetic control eyes with similar diabetic retinopathy (DR) severity that did not receive anti-VEGF therapy. The morphological characteristics of IRMAs on enface OCTA imaging were graded by ...

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    14. Repeatability and reproducibility of vessel density measurements on optical coherence tomography angiography in diabetic retinopathy

      Repeatability and reproducibility of vessel density measurements on optical coherence tomography angiography in diabetic retinopathy

      Purpose Understanding the precision of measurements on and across optical coherence tomography angiography (OCTA) devices is critical for tracking meaningful change in disease. The purpose of this study is to investigate the repeatability and reproducibility of vessel area density and vessel skeleton density measurements from various commercial OCTA devices in diabetic eyes. Methods Patients were imaged three consecutive times each on three different OCTA devices. En face OCTA images of the superficial capillary plexus, deep capillary plexus, and full retinal layer were exported for analysis. Vessel area density and vessel skeleton density were calculated. The coefficient of repeatability (CoR) was ...

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    15. Correction propagation for user-assisted optical coherence tomography segmentation: general framework and application to Bruch’s membrane segmentation

      Correction propagation for user-assisted optical coherence tomography segmentation: general framework and application to Bruch’s membrane segmentation

      Optical coherence tomography (OCT) is a commonly used ophthalmic imaging modality. While OCT has traditionally been viewed cross-sectionally (i.e., as a sequence of B-scans), higher A-scan rates have increased interest in en face OCT visualization and analysis. The recent clinical introduction of OCT angiography (OCTA) has further spurred this interest, with chorioretinal OCTA being predominantly displayed via en face projections. Although en face visualization and quantitation are natural for many retinal features (e.g., drusen and vasculature), it requires segmentation. Because manual segmentation of volumetric OCT data is prohibitively laborious in many settings, there has been significant research and ...

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    16. Topographic analysis of macular choriocapillaris flow deficits in diabetic retinopathy using swept–source optical coherence tomography angiography

      Topographic analysis of macular choriocapillaris flow deficits in diabetic retinopathy using swept–source optical coherence tomography angiography

      Background The purpose of this study was to investigate the association between diabetic retinopathy (DR) severity and macular choriocapillaris (CC) flow deficit percentage (FD %) in different macular regions using swept-source optical coherence tomography angiography (SS-OCTA). Methods Diabetic patients with SS-OCTA images were graded by severity and retrospectively assessed. CC FD % was calculated in four different regions of the OCTA image: inner, middle, outer, and full-field region. The generalized estimating equations (GEE) approach for clustered eye data was used to determine effect size and significance of age and disease severity on FD % for each region. Results 160 eyes from 90 total ...

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    17. Diversity in optical coherence tomography normative databases: moving beyond race

      Diversity in optical coherence tomography normative databases: moving beyond race

      Normative databases of optical coherence tomography (OCT) metrics, such as retinal nerve fiber layer (RNFL) and macular thickness, are critical to clinical use of OCT imaging. In order to accurately represent the range of normal variation in patient populations, these normative databases must themselves be adequately diverse. Thus far, diversity in OCT normative databases has largely been defined as racial diversity. However, this has largely been based on self-reported “race,” which is inconsistent and generally not scientifically rigorous as a form of categorization. Moreover, there is a great deal of variation even within any single racial group, suggesting that other ...

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    18. SPATIAL DISTRIBUTION OF CHORIOCAPILLARIS IMPAIRMENT IN EYES WITH CHOROIDAL NEOVASCULARIZATION SECONDARY TO AGE-RELATED MACULAR DEGENERATION: A Quantitative OCT Angiography Study

      SPATIAL DISTRIBUTION OF CHORIOCAPILLARIS IMPAIRMENT IN EYES WITH CHOROIDAL NEOVASCULARIZATION SECONDARY TO AGE-RELATED MACULAR DEGENERATION: A Quantitative OCT Angiography Study

      Purpose: To develop an optical coherence tomography angiography ( OCTA )-based framework for quantitatively analyzing the spatial distribution of choriocapillaris (CC) impairment around choroidal neovascularization ( CNV ) secondary to age-related macular degeneration. Methods: In a retrospective, cross-sectional study, 400-kHz swept-source OCTA images from 7 eyes of 6 patients with CNV secondary to age-related macular degeneration were quantitatively analyzed using custom software. A lesion-centered zonal OCTA analysis technique—which portioned the field-of-view into zones relative to CNV boundaries—was developed to quantify the spatial dependence of CC flow deficits. Results: Quantitative, lesion-centered zonal analysis of CC OCTA images revealed highest flow-deficit percentages near ...

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    19. How SD-OCT is enhancing our management of DR

      How SD-OCT is enhancing our management of DR

      Laser therapy was a major breakthrough in diabetic retinopathy treatment, with its efficacy validated by a number of clinical studies in the last three decades of the 20th century. However, it relied on fundus photography and fluorescein angiography to diagnose clinically significant macular edema. Since then, optical coherence tomography has revolutionized the clinical management of diabetic macular edema because of its widespread availability, ease of use, and ability to quantify DME noninvasively. This tool has become even more powerful coupled with the emergence of pharmacotherapies to treat the disease. Here, we review how OCT has changed the way retina specialists ...

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    20. A Framework for Multiscale Quantitation of Relationships Between Choriocapillaris Flow Impairment and Geographic Atrophy Growth

      A Framework for Multiscale Quantitation of Relationships Between Choriocapillaris Flow Impairment and Geographic Atrophy Growth

      Purpose To develop a multiscale analysis framework for investigating the relationships between geographic atrophy (GA) growth rate and choriocapillaris (CC) blood flow impairment using optical coherence tomography (OCT) and OCT angiography (OCTA). Design Retrospective case series. Methods We developed an OCT/OCTA analysis framework that quantitatively measures GA growth rates at global and local scales, and CC impairment at global, zonal, and local scales. A geometric GA growth model was used to measure local GA growth rates. The utility of the framework was demonstrated on 7 eyes with GA imaged at two time points using a prototype 400 kHz, 1050 ...

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    21. Global Analysis of Macular Choriocapillaris Perfusion in Dry Age-Related Macular Degeneration using Swept-Source Optical Coherence Tomography Angiography

      Global Analysis of Macular Choriocapillaris Perfusion in Dry Age-Related Macular Degeneration using Swept-Source Optical Coherence Tomography Angiography

      Purpose : Swept-source optical coherence tomography angiography (SS-OCTA) was used to investigate if the clinical stage of dry age-related macular degeneration (AMD) was correlated with global and regional macular choriocapillaris (CC) perfusion. Methods : In this retrospective, cross-sectional study, 6 × 6-mm SS-OCTA images from eyes with early, intermediate, and advanced dry AMD (56 eyes, 41 patients) were analyzed using algorithms described in the literature to assess regional flow deficit percentage (FD%) and average flow deficit size. Regions were defined by concentric areas centered on the fovea: a 1-mm-diameter area, 3-mm-diameter ring, 5-mm-diameter area, 5-mm-diameter ring, and 6 × 6-mm whole image. Data were ...

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    22. Retinal Nonperfusion Relationship to Arteries or Veins Observed on Widefield Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Retinal Nonperfusion Relationship to Arteries or Veins Observed on Widefield Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Purpose : To evaluate whether retinal capillary nonperfusion is found predominantly adjacent to arteries or veins in eyes with diabetic retinopathy (DR). Methods : Sixty-three eyes from 44 patients with proliferative DR (PDR) or non-PDR (NPDR) were included. Images (12 × 12-mm) foveal-centered optical coherence tomography (OCT) angiography (OCTA) images were taken using the Zeiss Plex Elite 9000. In 37 eyes, widefield montages with five fixation points were also obtained. A semiautomatic algorithm that detects nonperfusion in full-retina OCT slabs was developed, and the percentages of capillary nonperfusion within the total image area were calculated. Retinal arteries and veins were manually traced. Based ...

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    23. DISTINGUISHING INTRARETINAL MICROVASCULAR ABNORMALITIES FROM RETINAL NEOVASCULARIZATION USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

      DISTINGUISHING INTRARETINAL MICROVASCULAR ABNORMALITIES FROM RETINAL NEOVASCULARIZATION USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

      Purpose: With the increasing prevalence of diabetes, fast, noninvasive identification of proliferative diabetic retinopathy ( PDR ) becomes essential. This study evaluated the utility of optical coherence tomography angiography ( OCTA ) to characterize intraretinal microvascular abnormalities ( IRMA ) and retinal neovascularization (NV). Methods: Patients with severe non- PDR or PDR were imaged with fluorescein angiography and widefield swept-source OCTA (Zeiss Plex Elite 9000; Carl Zeiss Meditec, Dublin, CA). Regions suspicious for IRMA or retinal NV were identified and the OCTA , including flow overlay on the co-registered structural optical coherence tomography, and fluorescein angiography images were graded by two masked readers. Results: Ninety-six foci of ...

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    24. Reply to Correspondence: Impact of Binarization Thresholding and Brightness/Contrast Adjustment Methodology on Optical Coherence Tomography Angiography Image Quantification

      Reply to Correspondence: Impact of Binarization Thresholding and Brightness/Contrast Adjustment Methodology on Optical Coherence Tomography Angiography Image Quantification

      We thank Dr Rabiolo and associates for their interest in our work and their correspondence.1 We also applaud them for their valuable study that examined the effect of binarization thresholding on vessel area density (VAD) in retinal vascular optical coherence tomography angiography (OCTA) images.2 In their correspondence, they highlight several points regarding our results and conclusions compared with their own findings.

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    1. (84 articles) Nadia K. Waheed
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