1. Articles from David J. Wilson

    1-21 of 21
    1. Automated Quantification of Nonperfusion Areas in 3 Vascular Plexuses With Optical Coherence Tomography Angiography in Eyes of Patients With Diabetes

      Automated Quantification of Nonperfusion Areas in 3 Vascular Plexuses With Optical Coherence Tomography Angiography in Eyes of Patients With Diabetes

      Importance Diabetic retinopathy (DR) is a leading cause of vision loss that is managed primarily through qualitative clinical examination of the retina. Optical coherence tomography angiography (OCTA) may offer an objective and quantitative method of evaluating DR. Objective To quantify capillary nonperfusion in 3 vascular plexuses in the macula of eyes patients with diabetes of various retinopathy severity using projection-resolved OCTA (PR-OCTA). Design, Setting, and Participants Cross-sectional study at a tertiary academic center comprising 1 eye each from healthy control individuals and patients with diabetes at different severity stages of retinopathy. Data were acquired and analyzed between January 2015 and ...

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    2. Automated detection of photoreceptor disruption in mild diabetic retinopathy on volumetric optical coherence tomography

      Automated detection of photoreceptor disruption in mild diabetic retinopathy on volumetric optical coherence tomography

      Diabetic retinopathy is a pathology where microvascular circulation abnormalities ultimately result in photoreceptor disruption and, consequently, permanent loss of vision. Here, we developed a method that automatically detects photoreceptor disruption in mild diabetic retinopathy by mapping ellipsoid zone reflectance abnormalities from en face optical coherence tomography images. The algorithm uses a fuzzy c-means scheme with a redefined membership function to assign a defect severity level on each pixel and generate a probability map of defect category affiliation. A novel scheme of unsupervised clustering optimization allows accurate detection of the affected area. The achieved accuracy, sensitivity and specificity were about 90 ...

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    3. Reflectance-based projection-resolved optical coherence tomography angiography [Invited]

      Reflectance-based projection-resolved optical coherence tomography angiography [Invited]

      O ptical coherence tomography angiography (OCTA) is limited by projection artifacts from the superficial blood vessels onto deeper layers. We have recently described projection-resolved (PR) OCTA that solves the ambiguity between in situ flow and flow projection along each axial scan and suppresses the artifact on both en face and cross-sectional angiograms. While this method significantly improved the depth resolution of OCTA, the vascular integrity of the deeper layers was not fully preserved. In this study, we propose a novel reflectance-based projection-resolved (rbPR) OCTA algorithm which uses OCT reflectance to enhance the flow signal and suppress the projection artifacts in ...

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    4. Automated boundary detection of the optic disc and layer segmentation of the peripapillary retina in volumetric structural and angiographic optical coherence tomography

      Automated boundary detection of the optic disc and layer segmentation of the peripapillary retina in volumetric structural and angiographic optical coherence tomography

      To improve optic disc boundary detection and peripapillary retinal layer segmentation, we propose an automated approach for structural and angiographic optical coherence tomography. The algorithm was performed on radial cross-sectional B-scans. The disc boundary was detected by searching for the position of Bruch’s membrane opening, and retinal layer boundaries were detected using a dynamic programming-based graph search algorithm on each B-scan without the disc region. A comparison of the disc boundary using our method with that determined by manual delineation showed good accuracy, with an average Dice similarity coefficient ≥0.90 in healthy eyes and eyes with diabetic retinopathy ...

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    5. Automated three-dimensional registration and volume rebuilding for wide-field angiographic and structural optical coherence tomography

      Automated three-dimensional registration and volume rebuilding for wide-field angiographic and structural optical coherence tomography

      We propose a three-dimensional (3-D) registration method to correct motion artifacts and construct the volume structure for angiographic and structural optical coherence tomography (OCT). This algorithm is particularly suitable for the nonorthogonal wide-field OCT scan acquired by a ultrahigh-speed swept-source system ( > 200    kHz >200  kHz A-scan rate). First, the transverse motion artifacts are corrected by the between-frame registration based on en face OCT angiography (OCTA). After A-scan transverse translation between B-frames, the axial motions are corrected based on the rebuilt boundary of inner limiting membrane. Finally, a within-frame registration is performed for local optimization based on cross-sectional OCTA. We evaluated ...

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    6. Automated detection of dilated capillaries on optical coherence tomography angiography

      Automated detection of dilated capillaries on optical coherence tomography angiography

      Automated detection and grading of angiographic high-risk features in diabetic retinopathy can potentially enhance screening and clinical care. We have previously identified capillary dilation in angiograms of the deep plexus in optical coherence tomography angiography as a feature associated with severe diabetic retinopathy. In this study, we present an automated algorithm that uses hybrid contrast to distinguish angiograms with dilated capillaries from healthy controls and then applies saliency measurement to map the extent of the dilated capillary networks. The proposed algorithm agreed well with human grading.

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    7. Optical coherence tomographic angiography of choroidal neovascularization ill-defined with fluorescein angiography

      Optical coherence tomographic angiography of choroidal neovascularization ill-defined with fluorescein angiography

      Purpose To evaluate the morphological structure of ill-defined choroidal neovascularisation (CNV) with traditional fluorescein angiography (FA) compared with optical coherence tomographic angiography (OCTA). Methods A retrospective case series study of 11 eyes with ill-defined CNV on FA was performed. Eyes were scanned with commercially available spectral-domain optical coherence tomography (OCT) (70 000 A-scans/s). The split-spectrum amplitude-decorrelation angiography (SSADA) algorithm was used to distinguish blood flow from static tissue. En face OCT angiograms were compared with FA. Results Eleven cases of ill-defined CNV on FA were identified from 10 study participants. Mean age of the participants was 74.5±6 ...

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    8. Visualization of 3 Distinct Retinal Plexuses by Projection-Resolved Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Visualization of 3 Distinct Retinal Plexuses by Projection-Resolved Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Importance Projection artifacts in optical coherence tomography angiography (OCTA) blur the retinal vascular plexuses together and limit visualization of the individual plexuses. Objective To describe projection-resolved (PR) OCTA in eyes with diabetic retinopathy (DR) and healthy eyes. Design, Setting, and Participants In this case-control study, patients with DR and healthy controls were enrolled in this observational study from January 26, 2015, to December 4, 2015, at a tertiary academic center. Spectral-domain, 70-kHz OCT obtained 3 × 3-mm macular scans. The PR algorithm suppressed projection artifacts. A semiautomated segmentation algorithm divided PR-OCTA into superficial, intermediate, and deep retinal plexuses. Two masked graders ...

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    9. Automated Quantification of Nonperfusion in Three Retinal Plexuses Using Projection-Resolved Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Automated Quantification of Nonperfusion in Three Retinal Plexuses Using Projection-Resolved Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Purpose : The purpose of this study was to evaluate an automated algorithm for detecting avascular area (AA) in optical coherence tomography angiograms (OCTAs) separated into three individual plexuses using a projection-resolved technique. Methods : A 3 × 3 mm macular OCTA was obtained in 13 healthy and 13 mild nonproliferative diabetic retinopathy (NPDR) participants. A projection-resolved algorithm segmented OCTA into three vascular plexuses: superficial, intermediate, and deep. An automated algorithm detected AA in each of the three plexuses that were segmented and in the combined inner-retinal angiograms. We assessed the diagnostic accuracy of extrafoveal and total AA using segmented and combined angiograms ...

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    10. Evaluation of artifact reduction in optical coherence tomography angiography with real-time tracking and motion correction technology

      Evaluation of artifact reduction in optical coherence tomography angiography with real-time tracking and motion correction technology

      Artifacts introduced by eye motion in optical coherence tomography angiography (OCTA) affect the interpretation of images and the quantification of parameters with clinical value. Eradication of such artifacts in OCTA remains a technical challenge. We developed an algorithm that recognizes five different types of motion artifacts and used it to evaluate the performance of three motion removal technologies. On en face maximum projection of flow images, the summed flow signal in each row and column and the correlation between neighboring rows and columns were calculated. Bright line artifacts were recognized by large summed flow signal. Drifts, distorted lines, and stretch ...

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    11. Projection-resolved optical coherence tomographic angiography

      Projection-resolved optical coherence tomographic angiography

      Shadowgraphic projection artifacts from superficial vasculature interfere with the visualization of deeper vascular networks in optical coherence tomography angiography (OCT-A). We developed a novel algorithm to remove this artifact by resolving the ambiguity between in situ and projected flow signals. The algorithm identifies voxels with in situ flow as those where intensity-normalized decorrelation values are higher than all shallower voxels in the same axial scan line. This “projection-resolved” (PR) algorithm effectively suppressed the projection artifact on both en face and cross-sectional angiograms and enhanced depth resolution of vascular networks. In the human macula, the enhanced angiograms show three distinct vascular ...

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    12. Automated volumetric segmentation of retinal fluid on optical coherence tomography

      Automated volumetric segmentation of retinal fluid on optical coherence tomography

      We propose a novel automated volumetric segmentation method to detect and quantify retinal fluid on optical coherence tomography (OCT). The fuzzy level set method was introduced for identifying the boundaries of fluid filled regions on B-scans (x and y-axes) and C-scans (z-axis). The boundaries identified from three types of scans were combined to generate a comprehensive volumetric segmentation of retinal fluid. Then, artefactual fluid regions were removed using morphological characteristics and by identifying vascular shadowing with OCT angiography obtained from the same scan. The accuracy of retinal fluid detection and quantification was evaluated on 10 eyes with diabetic macular edema ...

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    13. Structure-Function Modeling of Optical Coherence Tomography and Standard Automated Perimetry in the Retina of Patients with Autosomal Dominant Retinitis Pigmentosa

      Structure-Function Modeling of Optical Coherence Tomography and Standard Automated Perimetry in the Retina of Patients with Autosomal Dominant Retinitis Pigmentosa

      Purpose To assess relationships between structural and functional biomarkers, including new topographic measures of visual field sensitivity, in patients with autosomal dominant retinitis pigmentosa. Methods Spectral domain optical coherence tomography line scans and hill of vision (HOV) sensitivity surfaces from full-field standard automated perimetry were semi-automatically aligned for 60 eyes of 35 patients. Structural biomarkers were extracted from outer retina b-scans along horizontal and vertical midlines. Functional biomarkers were extracted from local sensitivity profiles along the b-scans and from the full visual field. These included topographic measures of functional transition such as the contour of most rapid sensitivity decline around ...

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    14. Automated Quantification of Capillary Nonperfusion Using Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Automated Quantification of Capillary Nonperfusion Using Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Importance Macular ischemia is a key feature of diabetic retinopathy (DR). Quantification of macular ischemia has potential as a biomarker for DR. Objective To assess the feasibility of automated quantification of capillary nonperfusion as a potential sign of macular ischemia using optical coherence tomography (OCT) angiography. Design, Setting, and Participants An observational study conducted in a tertiary, subspecialty, academic practice evaluated macular nonperfusion with 6 × 6-mm OCT angiography obtained with commercially available 70-kHz OCT and fluorescein angiography (FA). The study was conducted from January 22 to September 18, 2014. Data analysis was performed from October 1, 2014, to April 7 ...

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    15. Advanced image processing for optical coherence tomographic angiography of macular diseases

      Advanced image processing for optical coherence tomographic angiography of macular diseases

      This article provides an overview of advanced image processing for three dimensional (3D) optical coherence tomographic (OCT) angiography of macular diseases, including age-related macular degeneration (AMD) and diabetic retinopathy (DR). A fast automated retinal layers segmentation algorithm using directional graph search was introduced to separates 3D flow data into different layers in the presence of pathologies. Intelligent manual correction methods are also systematically addressed which can be done rapidly on a single frame and then automatically propagated to full 3D volume with accuracy better than 1 pixel. Methods to visualize and analyze the abnormalities including retinal and choroidal neovascularization, retinal ...

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    16. DETECTION OF NONEXUDATIVE CHOROIDAL NEOVASCULARIZATION IN AGE-RELATED MACULAR DEGENERATION WITH OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

      DETECTION OF NONEXUDATIVE CHOROIDAL NEOVASCULARIZATION IN AGE-RELATED MACULAR DEGENERATION WITH OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

      Purpose: To evaluate eyes with age-related macular degeneration and high-risk characteristics for choroidal neovascularization (CNV) with optical coherence tomographic (OCT) angiography to determine whether earlier detection of CNV is possible. Methods: Eyes with drusen, pigmentary changes, and with CNV in the fellow eye were scanned with a 70-kHz spectral domain OCT system (Optovue RTVue-XR Avanti). The split-spectrum amplitude-decorrelation angiography (SSADA) algorithm was used to distinguish blood flow from static tissue. Two masked graders reviewed scans for CNV, defined as flow in the outer retinal/sub-RPE slab. Choroidal neovascularization flow area repeatability and between-grader reproducibility were calculated. Results: Of 32 eyes ...

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    17. OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FEATURES OF DIABETIC RETINOPATHY

      OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FEATURES OF DIABETIC RETINOPATHY

      Purpose: To describe the optical coherence tomography angiography features of diabetic retinopathy. Methods: Using a 70 kHz optical coherence tomography and the split-spectrum amplitude decorrelation angiography algorithm, 6 mm x 6 mm 3-dimensional angiograms of the macula of 4 patients with diabetic retinopathy were obtained and compared with fluorescein angiography for features cataloged by the Early Treatment of Diabetic Retinopathy Study. Results: Optical coherence tomography angiography detected enlargement and distortion of the foveal avascular zone, retinal capillary dropout, and pruning of arteriolar branches. Areas of capillary loss obscured by fluorescein leakage on fluorescein angiography were more clearly defined on optical ...

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    18. Quantitative optical coherence tomography angiography of vascular abnormalities in the living human eye

      Quantitative optical coherence tomography angiography of vascular abnormalities in the living human eye

      Retinal vascular diseases are important causes of vision loss. A detailed evaluation of the vascular abnormalities facilitates diagnosis and treatment in these diseases. Optical coherence tomography (OCT) angiography using the highly efficient split-spectrum amplitude decorrelation angiography algorithm offers an alternative to conventional dye-based retinal angiography. OCT angiography has several advantages, including 3D visualization of retinal and choroidal circulations (including the choriocapillaris) and avoidance of dye injection-related complications. Results from six illustrative cases are reported. In diabetic retinopathy, OCT angiography can detect neovascularization and quantify ischemia. In age-related macular degeneration, choroidal neovascularization can be observed without the obscuration of details caused ...

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    19. Quantitative Optical Coherence Tomography Angiography of Choroidal Neovascularization in Age-related Macular Degeneration

      Quantitative Optical Coherence Tomography Angiography of Choroidal Neovascularization in Age-related Macular Degeneration

      Purpose To detect and quantify choroidal neovascularization (CNV) in patients with age-related macular degeneration (AMD) using optical coherence tomography (OCT) angiography. Design Observational, cross-sectional study. Participants A total of 5 normal subjects and 5 subjects with neovascular AMD were included. Methods A total of 5 eyes with neovascular AMD and 5 normal age-matched controls were scanned by a high-speed (100 000 A-scans/seconds) 1050-nm wavelength swept-source OCT. The macular angiography scan covered a 3×3-mm area and comprised 200×200×8 A-scans acquired in 3.5 seconds. Flow was detected using the split-spectrum amplitude-decorrelation angiography (SSADA) algorithm. Motion artifacts were ...

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    20. High-resolution wide-field imaging of retinal and choroidal blood perfusion with optical microangiography

      High-resolution wide-field imaging of retinal and choroidal blood perfusion with optical microangiography
      We present high-resolution wide-field imaging of retinal and choroidal blood perfusion with optical microangiography (OMAG) technology. Based on spatial frequency analysis, OMAG is capable of visualizing the vascular perfusion map down to capillary-level resolution. An OMAG system operating at 840 nm is used with an A-scan rate of 27,000 Hz, axial resolution of 8 µm, and sensitivity of 98 dB. To achieve wide-field imaging, we capture 16 optical coherence tomography (OCT) 3-D datasets in a sequential order, which together provide an area of ~7.4×7.4 mm2 at the posterior segment of the human eye. For each of ...
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    21. A Comparison of Optic Nerve Head Morphology Viewed by Spectral Domain Optical Coherence Tomography and By Serial Histology

      PURPOSE: To compare serial optic nerve head (ONH) histology with interpolated B-scans generated from a three-dimensional (3D) spectral domain OCT (SD-OCT) ONH volume acquired in vivo from the same normal monkey eye. METHODS: A 15°, ONH SD-OCT volume was acquired in a normal monkey eye, with IOP manometrically controlled at 10 mmHg, using the Heidelberg Spectralis. Following perfusion fixation at 10 mmHg, the ONH was trephined, embedded in a paraffin block and serial sagittal sections were cut at 4 µm intervals. The location of each histologic section was identified within the optic disc photograph by matching the position of the ...
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    1-21 of 21
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    High-resolution wide-field imaging of retinal and choroidal blood perfusion with optical microangiography Quantitative Optical Coherence Tomography Angiography of Choroidal Neovascularization in Age-related Macular Degeneration Quantitative optical coherence tomography angiography of vascular abnormalities in the living human eye OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FEATURES OF DIABETIC RETINOPATHY DETECTION OF NONEXUDATIVE CHOROIDAL NEOVASCULARIZATION IN AGE-RELATED MACULAR DEGENERATION WITH OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY Advanced image processing for optical coherence tomographic angiography of macular diseases Automated Quantification of Capillary Nonperfusion Using Optical Coherence Tomography Angiography in Diabetic Retinopathy Automated Quantification of Nonperfusion in Three Retinal Plexuses Using Projection-Resolved Optical Coherence Tomography Angiography in Diabetic Retinopathy Visualization of 3 Distinct Retinal Plexuses by Projection-Resolved Optical Coherence Tomography Angiography in Diabetic Retinopathy Measurement of the Shrinkage of Natural and Simulated Lesions on Root Surfaces using CP-OCT Optic-Net: A Novel Convolutional Neural Network for Diagnosis of Retinal Diseases from Optical Tomography Images Double layer sign: A new optical coherence tomography finding in active tubercular serpiginous-like choroiditis to monitor activity