1. Articles from giovanni gregori

    1-24 of 91 1 2 3 4 »
    1. Mitigating the effects of choroidal hyper- and hypo-transmission defects on choroidal vascularity index assessments using optical coherence tomography

      Mitigating the effects of choroidal hyper- and hypo-transmission defects on choroidal vascularity index assessments using optical coherence tomography

      Background: Changes in choroidal vascularity index (CVI) are associated with multiple choroid-related ocular diseases. CVI is calculated as the area/volume ratio of vessels in the choroid, which could be affected by alterations in regional signal intensities due to hypo-transmission defects (hypoTDs) caused by drusen and retinal pigment epithelium (RPE) detachments, and hyper-transmission defects (hyperTDs) caused by the absence of RPE. To develop a simulation model to verify the CVI assessments in eyes with hyper/hypoTDs and demonstrate that accurate CVIs can be achieved after attenuation correction on swept-source optical coherence tomography (SS-OCT). Methods: A simulation model was developed on ...

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    2. Swept-Source Optical Coherence Tomography Detection of Bruch’s Membrane and Choriocapillaris Abnormalities in Sorsby Macular Dystrophy

      Swept-Source Optical Coherence Tomography Detection of Bruch’s Membrane and Choriocapillaris Abnormalities in Sorsby Macular Dystrophy

      Purpose: Swept-source optical coherence tomography angiography (SS-OCTA) was used to analyze Bruch's membrane (BM) and choriocapillaris (CC) abnormalities in undiagnosed family members with Sorsby macular dystrophy (SMD). Methods: In a family with SMD (TIMP3 Tyr191Cys), SS-OCTA imaging was performed using the 6X6mm scan patter and previously validated algorithms to detect abnormalities in BM and the CC, as well as the presence of reticular pseudodrusen (RPD) and macular neovascularization (MNV). Genetic analyses were performed for TIMP3 mutations. Results: Of eight family members, two were previously diagnosed with SMD and six were asymptomatic. SS-OCTA imaging of the 33-year-old proband revealed type ...

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    3. Automatic geographic atrophy segmentation using optical attenuation in OCT scans with deep learning

      Automatic geographic atrophy segmentation using optical attenuation in OCT scans with deep learning

      A deep learning algorithm was developed to automatically identify, segment, and quantify geographic atrophy (GA) based on optical attenuation coefficients (OACs) calculated from optical coherence tomography (OCT) datasets. Normal eyes and eyes with GA secondary to age-related macular degeneration were imaged with swept-source OCT using 6 × 6 mm scanning patterns. OACs calculated from OCT scans were used to generate customized composite en face OAC images. GA lesions were identified and measured using customized en face sub-retinal pigment epithelium (subRPE) OCT images. Two deep learning models with the same U-Net architecture were trained using OAC images and subRPE OCT images. Model ...

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    4. Diagnosing Persistent Hyper-Transmission Defects on En Face OCT Imaging of Age-Related Macular Degeneration

      Diagnosing Persistent Hyper-Transmission Defects on En Face OCT Imaging of Age-Related Macular Degeneration

      Purpose: A training exercise was performed to study the ability of graders to reliably identify precursor lesions to geographic atrophy (GA), known as persistent choroidal hyper-transmission defects (hyperTDs), using en face optical coherence tomography (OCT) images from eyes with non-exudative age-related macular degeneration (AMD). Design: Intergrader agreement study PARTICIPANTS: Eleven graders participated in this exercise. Methods: Formal training on how to identify persistent hyperTDs on en face OCT images was provided to the graders. Persistent hyperTDs were defined as bright lesions having a greatest linear dimension (GLD) of at least 250 μm. Training consisted of a tutorial session followed by ...

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    5. Interocular asymmetry of choroidal thickness and vascularity index measurements in normal eyes assessed by swept-source optical coherence tomography

      Interocular asymmetry of choroidal thickness and vascularity index measurements in normal eyes assessed by swept-source optical coherence tomography

      Background: To investigate the symmetry of interocular choroidal thickness and vascularity index measurements in normal eyes using swept-source optical coherence tomography (SS-OCT). Cross-sectional and observational study. This study included 244 eyes of 122 normal adults with ages uniformly distributed from 19 to 89 years. Methods: SS-OCT imaging was performed using a scanning pattern of 12×12 mm. Mean choroidal thickness (MCT) and choroidal vascularity index (CVI) measurements in the entire scanning region were obtained using a validated and published automatic method. The correlation and differences (including signed and absolute differences) between bilateral MCT and CVI measurements were analyzed at the ...

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    6. Analysis of correlations between local geographic atrophy growth rates and local OCT angiography-measured choriocapillaris flow deficits

      Analysis of correlations between local geographic atrophy growth rates and local OCT angiography-measured choriocapillaris flow deficits

      The purpose of this study is to quantitatively assess correlations between local geographic atrophy (GA) growth rates and local optical coherence tomography angiography (OCTA)-measured choriocapillaris (CC) flow deficits. Thirty-eight eyes from 27 patients with GA secondary to age-related macular degeneration (AMD) were imaged with a commercial 1050 nm swept-source OCTA instrument at 3 visits, each separated by ∼6 months. Pearson correlations were computed between local GA growth rates, estimated using a biophysical GA growth model, and local OCTA CC flow deficit percentages measured along the GA margins of the baseline visits. The p-values associated with the null hypothesis of ...

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    7. WIDE-FIELD SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF DIABETIC TRACTIONAL RETINAL DETACHMENTS BEFORE AND AFTER SURGICAL REPAIR

      WIDE-FIELD SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF DIABETIC TRACTIONAL RETINAL DETACHMENTS BEFORE AND AFTER SURGICAL REPAIR

      Purpose: Wide-field (WF) swept-source (SS) optical coherence tomography angiography (SS-OCTA) was used to image diabetic tractional retinal detachments (TRDs) before and after pars plana vitrectomy. The clinical utility of SS-OCTA was assessed. Methods: Patients with diabetic TRDs were imaged prospectively with SS-OCTA. Ultrawide-field imaging was obtained when possible. Postoperative WF SS-OCTA imaging was performed. Results: From January 2018 through December 2019, 31 eyes of 21 patients with diabetic TRDs were imaged. Wide-field SS-OCTA en-face images captured all areas of TRD and fibrovascular proliferation within the posterior pole that were visualized on ultrawide-field imaging. Optical coherence tomography angiography B-scans revealed the ...

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    8. Swept-Source OCT En Face Imaging of Paravascular Inner Retinal Defects

      Swept-Source OCT En Face Imaging of Paravascular Inner Retinal Defects

      Widefield swept-source optical coherence tomography angiography (SS-OCTA) was performed on eyes with paravascular inner retinal defects (PIRDs) and the morphological alterations of PIRDs were described. Patients with PIRDs were imaged using 12 mm × 12 mm SS-OCTA scans. En face structural and angiographic images of the superficial retinal layers were reviewed along with retinal thickness maps. SS-OCTA en face structural images identified dark, scalloped regions along major retinal veins that corresponded to PIRDs on B-scans. The authors concluded that imaging with both structural and angiographic en face OCT was useful for the diagnosis and monitoring of patients with PIRDs.

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    9. Swept-Source OCT Angiographic Characteristics of Treatment-Naïve Nonexudative Macular Neovascularization in AMD Prior to Exudation

      Swept-Source OCT Angiographic Characteristics of Treatment-Naïve Nonexudative Macular Neovascularization in AMD Prior to Exudation

      Purpose: To investigate the characteristics of treatment-naïve nonexudative macular neovascularization (MNV) in age-related macular degeneration before the onset of exudation using swept-source optical coherence tomography angiography. Methods: MNV area, choriocapillaris (CC) flow deficits (FDs), vessel area density (VAD), vessel skeleton density (VSD), retinal pigment epithelial detachment (PED) volume, mean choroidal thickness (MCT), and choroid vascularity index (CVI) measurements were assessed at two visits prior to exudation. We compared measurements made at the second visit and the rate of change between visits in eyes with and without exudation. The differences in these parameters between eyes with and without subsequent exudation ...

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    10. Validation of a Novel Automated Algorithm to Measure Drusen Volume and Area Using Swept Source Optical Coherence Tomography Angiography

      Validation of a Novel Automated Algorithm to Measure Drusen Volume and Area Using Swept Source Optical Coherence Tomography Angiography

      Purpose : The purpose of this study was to validate a novel automated swept source optical coherence tomography angiography (SS-OCTA) algorithm to measure elevations of the retinal pigment epithelium (RPE) in eyes with nonexudative age-related macular degeneration (neAMD). Methods : Patients with drusen were enrolled in a prospective optical coherence tomography (OCT) study and underwent both spectral domain OCT (SD-OCT) and SS-OCTA imaging at the same visit using the 6 × 6 mm scan patterns. The RPE elevation measurements (square root area and cube root volume) from the SS-OCTA algorithm were compared with the automated validated SD-OCT algorithm on the instrument. Standard deviations ...

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    11. Replacement of polyps with type 1 macular neovascularization in polypoidal choroidal vasculopathy imaged with swept source OCT angiography

      Replacement of polyps with type 1 macular neovascularization in polypoidal choroidal vasculopathy imaged with swept source OCT angiography

      Purpose: To investigate the morphological changes of polyps in eyes with polypoidal choroidal vasculopathy (PCV) after treatment with vascular endothelial growth factor (VEGF) inhibitors using swept source optical coherence tomography angiography (SS-OCTA). Observations: Following anti-VEGF therapy, polyps were found to evolve into typical type 1 macular neovascularization (MNV) in five eyes. In all of these five eyes, a polypoidal lesion was detected adjacent to a serous or hemorrhagic retinal pigment epithelial detachment (PED). Conclusions and importance: Polypoidal lesions in PCV can evolve into typical type 1 MNV. This morphological evolution suggests that these polyps are clusters of tangled vessels that ...

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    12. Widefield en face optical coherence tomography monitoring of the peri-venular fern-like pattern of paracentral acute middle maculopathy

      Widefield en face optical coherence tomography monitoring of the peri-venular fern-like pattern of paracentral acute middle maculopathy

      Purpose To demonstrate the ability of widefield en face swept source optical coherence tomography (OCT) imaging to monitor peri-venular fern-like patterns of paracentral acute middle maculopathy (PAMM) associated with retinal arterial occlusions. Observations The peri-venular fern-like pattern of PAMM was diagnosed on the 12 × 12 mm en face structural OCT images from three patients. Fluorescein angiography images were unremarkable. Over time, all three patients demonstrated significant improvement in visual acuity with resolution of their peri-venular PAMM. Conclusions and Importance: The peri-venular fern-like pattern of PAMM is usually associated with retinal vein occlusions, but we identified three cases with this pattern ...

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    13. Correlations Between Choriocapillaris and Choroidal Measurements and the Growth of Geographic Atrophy using Swept Source OCT Imaging

      Correlations Between Choriocapillaris and Choroidal Measurements and the Growth of Geographic Atrophy using Swept Source OCT Imaging

      Purpose The correlations between enlargement rates (ERs) of geographic atrophy (GA) and choriocapillaris (CC) flow deficits (FDs), mean choroidal thickness (MCT), and choroidal vascularity index (CVI) were investigated using swept source optical coherence tomography (SS-OCT) in age-related macular degeneration (AMD). Design Retrospective review of prospective, observational case series. Methods Eyes with GA from AMD were imaged with SS-OCT (PLEX® Elite 9000; Carl Zeiss Meditec, Inc, Dublin, CA) using 6x6 mm scan pattern. GA lesions were identified and measured using custom en face structural images and annual square root ERs of GA were calculated. At baseline, CC FDs from different regions ...

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    14. Comparison Between Graders in Detection of Diabetic Neovascularization with Swept Source OCT Angiography and Fluorescein Angiography

      Comparison Between Graders in Detection of Diabetic Neovascularization with Swept Source OCT Angiography and Fluorescein Angiography

      Purpose To compare the ability of ophthalmologists to identify neovascularization (NV) in patients with proliferative diabetic retinopathy (PDR) using swept source optical coherence tomography angiography (SS-OCTA) and fluorescein angiography (FA). Design Retrospective study comparing diagnostic instruments. Methods Eyes with PDR or severe non-proliferative diabetic retinopathy and a high suspicion of NV based on clinical examination were imaged using SS-OCTA and FA at the same visit. Two separate grading sets consisting of scrambled, anonymized SS-OCTA and FA images were created. The ground truth for presence of NV was established by consensus of two graders with OCTA experience who did not participate ...

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    15. Pathological-Corneas Layer Segmentation and Thickness Measurement in OCT Images

      Pathological-Corneas Layer Segmentation and Thickness Measurement in OCT Images

      Purpose : The purpose of this study was to propose a new algorithm for the segmentation and thickness measurement of pathological corneas with irregular layers using a two-stage graph search and ray tracing. Methods : In the first stage, a graph, with only gradient edge-cost, is used to segment the air-epithelium and endothelium-aqueous boundaries. In the second stage, a graph, with gradient, directional, and multiplier edge-cost, is used to correct segmentation. The optical coherence tomography (OCT) image is flattened using the air-epithelium boundary and a graph search is used to segment the epithelium-Bowman's and Bowman's-stroma boundaries. Then, the OCT image ...

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    16. The effect of software versions on the measurement of retinal vascular densities using optical coherence tomography angiography

      The effect of software versions on the measurement of retinal vascular densities using optical coherence tomography angiography

      Background The goal of the study was to determine the effect of different software versions on the measurement of retinal vessel densities using optical coherence tomography angiography (OCTA) in normal subjects. Methods Thirty-two eyes of eighteen healthy subjects were imaged using two OCTA devices: the Optovue RTVue and the Zeiss Cirrus. The macular 3 × 3 mm scan protocol was used. The images acquired using the Optovue OCTA device were exported using two different software versions in the system and compared to the images acquired through the Zeiss OCTA. In addition, the Optovue OCTA images were exported after manual adjustment of ...

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    17. Validation of a Compensation Strategy used to Detect Choriocapillaris Flow Deficits Under Drusen with Swept Source OCT Angiography

      Validation of a Compensation Strategy used to Detect Choriocapillaris Flow Deficits Under Drusen with Swept Source OCT Angiography

      Purpose A compensation strategy that was developed to measure the choriocapillaris (CC) flow deficits (FDs) under drusen was tested in eyes with large drusen from age-related macular degeneration (AMD) before and after the drusen spontaneously resolved without evidence of disease progression. Design Prospective, observational consecutive case series. Methods Patients with AMD were enrolled in a prospective SS-OCT imaging study (PLEX® Elite 9000, Carl Zeiss Meditec). Consecutive eyes with large drusen were followed, and eyes that underwent spontaneous collapse of drusen without evidence of disease progression were identified retrospectively. The drusen-resolved regions were manually outlined. CC FDs were measured using a ...

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    18. Eliminating Visual Acuity and Dilated Fundus Exams Improves Cost Efficiency of Performing OCT-Guided Intravitreal Injections

      Eliminating Visual Acuity and Dilated Fundus Exams Improves Cost Efficiency of Performing OCT-Guided Intravitreal Injections

      Purpose The clinic efficiency and cost savings achieved by eliminating formal visual acuity (VA) and dilated fundus exams (DFEs) were assessed for established patients receiving OCT-guided intravitreal injections. Design Comparative cost analysis Methods Two different treatment models were evaluated. The first model included patients undergoing routine VA assessment, DFEs, OCT imaging, and intravitreal injections. The second model eliminated the routine VA assessment and DFE, while utilizing OCT imaging through an undilated pupil followed by the intravitreal injection. The two models incorporated both bevacizumab and aflibercept. The number of patients per clinic day, the cost per visit, and the daily revenues ...

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    19. A Comparison Study of Polypoidal Choroidal Vasculopathy Imaged with Indocyanine Green Angiography and Swept Source OCT Angiography

      A Comparison Study of Polypoidal Choroidal Vasculopathy Imaged with Indocyanine Green Angiography and Swept Source OCT Angiography

      Purpose Indocyanine green angiography (ICGA) was compared with swept source optical coherence tomography angiography (SS-OCTA) for the detection of polypoidal choroidal vasculopathy (PCV). Design Retrospective, cross-sectional. Methods Patients with treatment-naïve PCV based on ICGA imaging underwent same day SS-OCTA imaging at Kyung Hee University Medical Center between April 2017 to November 2018. ICGA and SS-OCTA images were graded independently. SS-OCTA images were graded using both flow and structural information. Images were graded for the number of polypoidal lesions and the total lesion area, which included both the polypoidal lesions and the branching vascular networks (BVNs). Results A total of ...

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    20. Longitudinal Swept Source OCT Angiography of Juxtapapillary Retinal Capillary Hemangioblastoma

      Longitudinal Swept Source OCT Angiography of Juxtapapillary Retinal Capillary Hemangioblastoma

      In this case report, SS-OCTA identified the key diagnostic features of JRCH seen with multimodal imaging. Serial SS-OCTA imaging showed transient decreases in vascular congestion and exudation after intravitreal anti-VEGF injections. SS-OCTA may be the sole imaging modality needed for the diagnosis of JRCH, an important entity that is commonly misdiagnosed as disc edema or choroidal neovascularization. Transient responses to anti-VEGF therapy suggests that higher dose or sustained-release anti-VEGF therapy may be effective for retinal capillary hemangioblastomas.

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    21. Correlations between Different Choriocapillaris Flow Deficit Parameters in Normal Eyes using Swept Source OCT Angiography

      Correlations between Different Choriocapillaris Flow Deficit Parameters in Normal Eyes using Swept Source OCT Angiography

      Purpose Choriocapillaris (CC) imaging of normal eyes with swept-source optical coherence tomography SS-OCTA was performed, and the percentage of CC flow deficits (FD%) and the average area of CC flow deficits (FDa) were compared within given macular regions. Design A prospective, cross-sectional study. Methods Subjects with normal eyes ranging in age from their 20s through their 80s were imaged with SS-OCTA (PLEX Elite 9000, Carl Zeiss Meditec, Dublin, CA) using both 3x3 mm and 6x6 mm macular scan patterns. The CC images were generated using a previously published and validated algorithm. In both 3x3 mm and 6x6 mm scans, the ...

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    22. Two-Year Risk of Exudation in Eyes with Nonexudative Age-Related Macular Degeneration and Subclinical Neovascularization Detected with Swept Source Optical Coherence Tomography Angiography

      Two-Year Risk of Exudation in Eyes with Nonexudative Age-Related Macular Degeneration and Subclinical Neovascularization Detected with Swept Source Optical Coherence Tomography Angiography

      Purpose Swept source optical coherence tomography angiography (SS-OCTA) was used to study the prevalence, incidence, and natural history of subclinical macular neovascularization (MNV) in eyes with unilateral nonexudative age-related macular degeneration. Design Prospective cohort study. Methods Patients were imaged using 3- × 3-mm and 6- × 6-mm SS-OCTA scan patterns. MNV was detected using the outer retina to choriocapillaris en face slab. Prevalence and incidence of subclinical MNV, Kaplan–Meier cumulative estimates for the overall risk of exudation, and the association between neovascular lesion size and the risk of exudation were assessed through 2 years. Results From August 2014 through March 2018 ...

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    23. Widefield Swept-Source Optical Coherence Tomography Angiography of Proliferative Diabetic Retinopathy

      Widefield Swept-Source Optical Coherence Tomography Angiography of Proliferative Diabetic Retinopathy

      BACKGROUND AND OBJECTIVE: To demonstrate the utility of widefield swept-source optical coherence tomography angiography (SS-OCTA) for the diagnosis and management of proliferative diabetic retinopathy (PDR). PATIENTS AND METHODS: Consecutive patients with vision-threatening diabetic retinopathy were imaged with widefield SS-OCTA using the 12 mm × 12 mm scan pattern. RESULTS: Twenty-four eyes of 12 patients underwent SS-OCTA imaging. In all 24 eyes, the en face total retinal flow images detected areas of decreased retinal perfusion, and the en face vitreoretinal interface (VRI) slabs detected foci of retinal neovascularization (NV). NV was treated and followed using the VRI images. CONCLUSIONS: Widefield SS-OCTA is ...

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    24. Quantification of choriocapillaris with OCTA: a comparison study

      Quantification of choriocapillaris with OCTA: a comparison study

      Purpose To demonstrate the variation in quantitative choriocapillaris (CC) metrics with various binarization approaches using optical coherence tomography angiography (OCTA). Design Retrospective, observational, cross-sectional case series. Methods 3x3 mm and 6x6 mm macular OCTA scans were obtained from normal eyes and from eyes with drusen secondary to AMD. The CC slab was extracted and the CC flow deficits (FDs) were segmented with two previously published algorithms: fuzzy C-means approach (FCM method) and Phansalkar’s local thresholding (Phansalkar method). Four different values for the radius were used in order to investigate the effect on the FD segmentation when using the Phansalkar ...

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