1. Articles from Amir H. Kashani

    1-25 of 25
    1. The clinical potential of WF-OCT and OCTA

      The clinical potential of WF-OCT and OCTA

      O ptical coherence tomography, introduced in 1991, 1 has had a transformational impact on the diagnosis and management of macular pathology such as choroidal neovascularization and macular edema. In short order the application of OCT to diseases of the vitreoretinal interface also rapidly evolved. 2,3 With these applications, the importance of peripheral retinal imaging also emerged when investigators began to use montages of spectral-domain OCT images 4 or larger scan patterns 5 to explore vitreoretinal interface findings outside the macula. These studies revealed that OCT of the retinal periphery was a significantly underutilized application that could provide important diagnostic ...

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    2. Recommendations for OCTA reporting in retinal vascular disease: A Delphi approach by International Experts

      Recommendations for OCTA reporting in retinal vascular disease: A Delphi approach by International Experts

      Purpose: To develop a consensus nomenclature for reporting optical coherence tomography angiography (OCTA) findings in retinal vascular disease (e.g., diabetic retinopathy, retinal vein occlusion) by international experts. Design: Delphi-based survey SUBJECTS, PARTICIPANTS AND/OR CONTROLS: Twenty-five retinal vascular disease and OCTA imaging experts METHODS, INTERVENTION, OR TESTING: A Delphi method of consensus development was used, comprising two rounds of online questionnaires, followed by a face-to-face meeting conducted virtually. Twenty-five experts in retinal vascular disease and retinal OCTA imaging were selected to constitute the OCTA Nomenclature in Delphi Study Group for retinal vascular disease. The four main areas of consensus ...

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    3. OCTA Derived Vessel Skeleton Density Versus Flux and Their Associations With Systemic Determinants of Health

      OCTA Derived Vessel Skeleton Density Versus Flux and Their Associations With Systemic Determinants of Health

      Purpose: To examine the associations of optical coherence tomography angiography (OCTA)-derived retinal capillary flux with systemic determinants of health. Methods: This is a cross-sectional study of subjects recruited from the African American Eye Disease Study. A commercially available swept-source (SS)-OCTA device was used to image the central 3 × 3 mm macular region. Retinal capillary perfusion was assessed using vessel skeleton density (VSD) and flux. Flux approximates the number of red blood cells moving through vessel segments and is a novel metric, whereas VSD is a previously validated measure commonly used to quantify capillary density. The associations of OCTA ...

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    4. Capillary density and caliber as assessed by optical coherence tomography angiography may be significant predictors of diabetic retinopathy severity

      Capillary density and caliber as assessed by optical coherence tomography angiography may be significant predictors of diabetic retinopathy severity

      Purpose To validate retinal capillary density and caliber associations with diabetic retinopathy (DR) severity in different clinical settings. Methods This cross-sectional study assessed retinal capillary density and caliber in the superficial retinal layer of 3-mm OCTA scans centered on the fovea. Images were collected from non-diabetic controls and subjects with mild or referable DR (defined DR worse than mild DR) between February 2016 and December 2019 at secondary and tertiary eye care centers. Vessel Skeleton Density (VSD), a measure of capillary density, and Vessel Diameter Index (VDI), a measure of vascular caliber, were calculated from these images. Discriminatory performance of ...

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    5. Optical Coherence Tomography Angiography-Derived Flux As a Measure of Physiological Changes in Retinal Capillary Blood Flow

      Optical Coherence Tomography Angiography-Derived Flux As a Measure of Physiological Changes in Retinal Capillary Blood Flow

      Purpose: To compare optical coherence tomography angiography (OCTA)-derived flux with conventional OCTA measures of retinal vascular density in assessment of physiological changes in retinal blood flow. Methods: Healthy subjects were recruited, and 3 × 3-mm2 fovea-centered scans were acquired using commercially available swept-source OCTA (SS-OCTA) while participants were breathing room air, 100% O2, or 5% CO2. Retinal perfusion was quantified using vessel area density (VAD) and vessel skeleton density (VSD), as well as novel measures of retinal perfusion, vessel area flux (VAF) and vessel skeleton flux (VSF). Flux is proportional to the number of red blood cells moving through a ...

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    6. Standardization of optical coherence tomography angiography nomenclature in retinal vascular diseases: first survey results

      Standardization of optical coherence tomography angiography nomenclature in retinal vascular diseases: first survey results

      Purpose: To develop a consensus nomenclature for optical coherence tomography angiography (OCTA) findings in retinal vascular diseases. Design: Online survey using Delphi Method SUBJECTS, PARTICIPANTS AND/OR CONTROLS: Members of The Retina Society, European Society of Retina Specialists (EURETINA) and the Japanese Retina and Vitreous Society (JRVS). Methods, intervention, or testing: An online questionnaire on OCTA terminology in retinal vascular diseases was sent to members of The Retina Society, EURETINA and the JRVS. The respondents were divided into two groups (experts vs users) based on the number of their publications in this field. The respondents who had more than 5 ...

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    7. Classification of advanced and early stages of diabetic retinopathy from non-diabetic subjects by an ordinary least squares modeling method applied to OCTA images

      Classification of advanced and early stages of diabetic retinopathy from non-diabetic subjects by an ordinary least squares modeling method applied to OCTA images

      As the prevalence of diabetic retinopathy (DR) continues to rise, there is a need to develop computer-aided screening methods. The current study reports and validates an ordinary least squares (OLS) method to model optical coherence tomography angiography (OCTA) images and derive OLS parameters for classifying proliferative DR (PDR) and no/mild non-proliferative DR (NPDR) from non-diabetic subjects. OLS parameters were correlated with vessel metrics quantified from OCTA images and were used to determine predicted probabilities of PDR, no/mild NPDR, and non-diabetics. The classification rates of PDR and no/mild NPDR from non-diabetic subjects were 94% and 91%, respectively. The ...

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      Mentions: UCLA
    8. Quantifying Subclinical and Longitudinal Microvascular Changes Following Episcleral Plaque Brachytherapy Using Spectral Domain–Optical Coherence Tomography Angiography

      Quantifying Subclinical and Longitudinal Microvascular Changes Following Episcleral Plaque Brachytherapy Using Spectral Domain–Optical Coherence Tomography Angiography

      Purpose: This work assesses longitudinal microvascular changes in eyes treated with iodine-125 episcleral plaque brachytherapy (EPB). Methods: High-resolution optical coherence tomography angiograms (OCTAs) of the central 3 × 3-mm macula were obtained from iodine-125 EPB–treated and untreated fellow eyes of 61 patients. Previously validated semiautomated algorithms quantified capillary density (vessel skeleton density [VSD]) and caliber (vessel diameter index). Nonperfusion was also quantified as flow impairment region (FIR). Examinations from treated and fellow eyes obtained before treatment and at 6-month, 1-year, and 2-year intervals were compared using generalized estimating equation linear models. Dosimetry maps evaluated spatial correlation between radiation dose and ...

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    9. 3D Image Registration Based Atlas for Large Field of View Human Eye Optical Coherence Tomography

      3D Image Registration Based Atlas for Large Field of View Human Eye Optical Coherence Tomography

      Purpose : Optical coherence tomography (OCT) is a non-invasive imaging modality used for high resolution (10 μ) imaging of ocular tissue. Retinal cell layers are clearly visible on OCT providing a means for quantitative and topographical analysis. Medical atlases are important tools for detecting abnormal structural and anatomical tissue alterations, relative to a standardized normal. They can also serve as a reference for registration of individual images for deformation-based analysis. The purpose of the current study is to present a method for generating an atlas of the human eye using large field of view 3D OCT image volumes. Methods : Imaging was performed ...

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    10. 3D Shape Modeling and Analysis of Retinal Microvasculature in OCT-Angiography Images

      3D Shape Modeling and Analysis of Retinal Microvasculature in OCT-Angiography Images

      3D optical coherence tomography angiography (OCT-A) is a novel and non-invasive imaging modality for analyzing retinal diseases. The studies of microvasculature in 2D en face projection images have been widely implemented, but comprehensive 3D analysis of OCT-A images with rich depth-resolved microvascular information is rarely considered. In this paper, we propose a robust, effective, and automatic 3D shape modeling framework to provide a high-quality 3D vessel representation and to preserve valuable 3D geometric and topological information for vessel analysis. Effective vessel enhancement and extraction steps by means of curvelet denoising and optimally oriented flux (OOF) filtering are first designed to ...

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    11. Automated Deformation-Based Analysis of 3D Optical Coherence Tomography in Diabetic Retinopathy

      Automated Deformation-Based Analysis of 3D Optical Coherence Tomography in Diabetic Retinopathy

      Diabetic retinopathy (DR) is a significant microvascular complication of diabetes mellitus and a leading cause of vision impairment in working age adults. Optical coherence tomography (OCT) is a routinely used clinical tool to observe retinal structural and thickness alterations in DR. Pathological changes that alter the normal anatomy of the retina, such as intraretinal edema, pose great challenges for conventional layer-based analysis of OCT images. We present an alternative approach for the automated analysis of OCT volumes in DR research based on nonlinear registration. In our work, we first obtain an anatomically consistent volume of interest (VOI) in different OCT ...

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    12. Impaired Retinal Vascular Reactivity in Diabetic Retinopathy as Assessed by Optical Coherence Tomography Angiography

      Impaired Retinal Vascular Reactivity in Diabetic Retinopathy as Assessed by Optical Coherence Tomography Angiography

      Purpose : To assess retinal vascular reactivity in healthy controls and subjects with diabetic retinopathy (DR). Methods : A total of 22 healthy control eyes and 16 eyes with DR were enrolled. Images were acquired using a commercially available swept-source optical coherence tomography angiography (SS-OCTA) system. Three conditions were tested for each patient (hyperoxia, hypercapnia, and room-air) by employing a non-rebreathing apparatus that delivered appropriate gas mixtures (100% O 2 , 5% CO 2 , room air). Vessel skeleton density (VSD) and vessel diameter index (VDI) were compared between the conditions using mixed-model ANOVA adjusting for age and hypertension. Significant gas or interaction effects ...

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    13. Diagnostic Performance of Macular Versus Peripapillary Vessel Parameters by Optical Coherence Tomography Angiography for Glaucoma

      Diagnostic Performance of Macular Versus Peripapillary Vessel Parameters by Optical Coherence Tomography Angiography for Glaucoma

      Purpose : To compare the diagnostic ability of the vessel parameters in macular and peripapillary regions measured using spectral-domain optical coherence tomography angiography (SD-OCTA) in differentiating primary open-angle glaucoma (POAG) from healthy eyes. Methods : POAG patients and healthy subjects underwent 6 × 6-mm scans centered on the macula and optic nerve head. Commercially available automatic segmentation created en face images from SD-OCTA of the superficial retinal layer (SRL) of the macular (m) and peripapillary (cp) regions. Vessel area density (VAD), vessel skeleton density (VSD), vessel complexity index (VCI), and flux were calculated. Area under curve (AUC) statistics controlled for age and intereye ...

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    14. Normative Retinal Thicknesses in Common Animal Models of Eye Disease Using Spectral Domain Optical Coherence Tomography

      Normative Retinal Thicknesses in Common Animal Models of Eye Disease Using Spectral Domain Optical Coherence Tomography

      Purpose This study demonstrates a standardized approach to measuring retinal thickness (RT) using spectral domain optical coherence tomography (SD-OCT) in commonly used animal models of disease and reports a normative data set for future use. Materials and Methods Twenty normal eyes of 4 adult animal models (5 rats, 5 rabbits, 5 canines, and 5 mini-pigs) were used. Manual measurements were made on the commercially available Heidelberg Spectralis™ SD-OCT to determine the total, inner, and outer retinal thickness (RT) at fixed distances from the optic nerve head (ONH) (1, 2, 3, 4, 5, and 6 mm away) in order to control ...

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    15. Optical coherence tomography angiography: A comprehensive review of current methods and clinical applications

      Optical coherence tomography angiography: A comprehensive review of current methods and clinical applications

      OCT has revolutionized the practice of ophthalmology over the past 10–20 years. Advances in OCT technology have allowed for the creation of novel OCT-based methods. OCT-Angiography (OCTA) is one such method that has rapidly gained clinical acceptance since it was approved by the FDA in late 2016. OCTA images are based on the variable backscattering of light from the vascular and neurosensory tissue in the retina. Since the intensity and phase of backscattered light from retinal tissue varies based on the intrinsic movement of the tissue (e.g. red blood cells are moving, but neurosensory tissue is static), OCTA ...

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    16. Quantitative microvascular analysis of retinal venous occlusions by spectral domain optical coherence tomography angiography

      Quantitative microvascular analysis of retinal venous occlusions by spectral domain optical coherence tomography angiography

      Purpose To quantitatively evaluate the retinal microvasculature in human subjects with retinal venous occlusions (RVO) using optical coherence tomography angiography (OCTA). Design Retrospective, cross-sectional, observational case series. Participants Sixty subjects (84 eyes) were included (20 BRVO, 14 CRVO, 24 unaffected fellow eyes, and 26 controls). Methods OCTA was performed on a prototype, spectral domain-OCTA system in the 3x3mm central macular region. Custom software was used to quantify morphology and density of retinal capillaries using four quantitative parameters. The vasculature of the segmented retinal layers and nonsegmented whole retina were analyzed. Main outcome measures Fractal dimension (FD), vessel density (VD), skeletal ...

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    17. Quantifying Retinal Microvascular Changes in Uveitis Using Spectral-Domain Optical Coherence Tomography Angiography

      Quantifying Retinal Microvascular Changes in Uveitis Using Spectral-Domain Optical Coherence Tomography Angiography

      Purpose To quantify retinal capillary density and morphology in uveitis using SD-OCTA. Design Cross-sectional, observational study Methods Healthy and uveitic subjects were recruited from two tertiary care eye centers. Prototype SD-OCTA devices (Cirrus, Carl Zeiss Meditec, Inc., Dublin, CA) were used to generate 3x3 mm 2 OCTA images centered on the fovea. Subjects were placed into 3 groups based on the type of optical microangiography (OMAG) algorithm used for image processing (intensity- and/or phase) and type of retinal segmentation (automatic or manual). A semi-automated method was used to calculate skeleton density (SD), vessel density (VD), fractal dimension (FD), and ...

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    18. Quantifying Microvascular Density and Morphology in Diabetic Retinopathy Using Spectral-Domain Optical Coherence Tomography Angiography

      Quantifying Microvascular Density and Morphology in Diabetic Retinopathy Using Spectral-Domain Optical Coherence Tomography Angiography

      Purpose : To quantify changes in retinal microvasculature in diabetic retinopathy (DR) by using spectral-domain optical coherence tomography angiography (SD-OCTA). Methods : Retrospective, cross-sectional, observational study of healthy and diabetic adult subjects with and without DR. Retinal microvascular changes were assessed by using SD-OCTA images and an intensity-based optical microangiography algorithm. A semiautomated program was used to calculate indices of microvascular density and morphology in nonsegmented and segmented SD-OCTA images. Microvascular density was quantified by using skeleton density (SD) and vessel density (VD), while vessel morphology was quantified as fractal dimension (FD) and vessel diameter index (VDI). Statistical analyses were performed by ...

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    19. OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF RETINAL VENOUS OCCLUSION

      OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF RETINAL VENOUS OCCLUSION

      Purpose: To noninvasively evaluate the retinal microvasculature in human subjects with retinal venous occlusions using optical coherence tomography angiography and assess potential clinical applications. Methods: This was a prospective, observational study of adult human subjects with clinical and imaging findings demonstrating retinal venous occlusion. Subjects underwent complete ophthalmic examination and fluorescein angiography as appropriate for their standard of care. Optical coherence tomography angiography was performed on a prototype spectral domain-OCTA system in 3 mm x 3 mm and 6 mm x 6 mm regions centered on the fovea and parafoveal areas. Retinal vasculature was assessed within three horizontal slabs consisting ...

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    20. Optical Coherence Tomography Angiography of Diabetic Retinopathy in Human Subjects

      Optical Coherence Tomography Angiography of Diabetic Retinopathy in Human Subjects

      BACKGROUND AND OBJECTIVE: Optical coherence tomography angiography (OCTA) is a novel, non-invasive OCT technique capable of imaging the retinal vasculature. This study aims to evaluate the retinal microvasculature in diabetic human subjects with OCTA and assess potential clinical applications. PATIENTS AND METHODS: Cross-sectional study of 33 subjects with diabetic retinopathy. OCTA was performed on 3 mm × 3 mm sections using a swept-source OCTA prototype and a phase- and intensity-based contrasting algorithm. OCT angiograms were studied with corresponding clinical examination and fluorescein angiograms, when available, to assess accuracy and clinical utility. RESULTS: OCTA was able to demonstrate most clinically relevant vascular ...

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    21. Optical Coherence Tomography Angiography

      Optical Coherence Tomography Angiography

      A primer on this promising new technology for evaluating retinal vasculature. Optical coherence tomography (OCT) is a commonly used technology that noninvasively generates images of the retina in cross section or in three dimensions. 1-5 Advances in technology have facilitated additional applications of OCT such as phase-sensitive OCT, polarization-sensitive OCT, and spectroscopic OCT. 6 These methods hold the promise of combining structural information with functional imaging capabilities to assess the metabolic state of the retinal tissue. 7 This article reviews recent developments in the use of OCT technology for noninvasive assessment of the retinal vasculature. We refer to this technology ...

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    22. OCT Angiography in Healthy Human Subjects

      OCT Angiography in Healthy Human Subjects

      BACKGROUND AND OBJECTIVE: To noninvasively evaluate the retinal microvasculature in healthy human subjects with optical coherence tomography angiography (OCTA). PATIENTS AND METHODS: Cross-sectional, observational study of five healthy subjects. OCTA was performed on 3 × 3 mm(2) sections centered on the fovea, nasal macula, and temporal macula. Retinal vasculature was assessed within three horizontal slabs consisting of the inner, middle, and outer retina. The vasculature within each retinal slab was reconstructed using phase-based and intensity contrast-based algorithms and visualized as separate en face images. RESULTS: OCTA in healthy subjects demonstrates capillary networks consistent with previous histological studies. No retinal vessels ...

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    23. Quantitative Analysis of Retinal Structures Using Spectral Domain Optical Coherence Tomography in Normal Rabbits

      Quantitative Analysis of Retinal Structures Using Spectral Domain Optical Coherence Tomography in Normal Rabbits

      Purpose: The purpose of this study is to quantify the normal retinal thickness (RT) and retinal nerve fiber layer thickness (RNFLT), and to obtain cross-sectional area measurements of the main retinal artery and vein in the rabbit animal model using spectral domain optical coherence tomography (SD-OCT). Materials and methods: Fifteen eyes of 15 adult rabbits were used to obtain SD-OCT scans. RT, RNFLT and cross-sectional areas of the main retinal artery and vein were measured with a custom-made software grading tool (OCTOR) on selected B-scans at the edge of the optic nerve head and at 1, 2, 3 and 4 ...

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    24. Retinal Thickness Analysis by Race, Gender, and Age Using Stratus OCT

      Purpose: To detect differences in retinal thickness among patients of different race, gender, and age using Stratus OCT.Design: Cross-sectional study.Methods: In a multicenter, university-based study, 126 patients with no history of ocular disease were enrolled (78 diabetics without retinopathy and 48 nondiabetics). Optical coherence tomography measurements were performed using Stratus OCT. Statistical comparisons of center point foveal thickness and mean foveal thickness were made using generalized estimating equations adjusting for diabetic status, race, age, and gender.Results: The study population consisted of 36% male subjects, 39% Caucasian, 33% African-American, and 28% Hispanic. Mean foveal thickness was 191.6 ...

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    25. Quantitative Subanalysis of Intraretinal Cystoid Spaces and Outer Nuclear Layer using Optical Coherence Tomography in Neovascular Age-Related Macular Degeneration

      Purpose: To quantify intraretinal cystoid spaces (ICS) and the outer nuclear layer (ONL) using optical coherence tomography (OCT) in patients with neovascular age-related macular degeneration (AMD), and to investigate the correlation of these parameters with visual acuity. Methods: StratusOCT images from 53 patients receiving their initial treatment with intravitreal ranibizumab were collected. Images were analyzed using custom software (entitled OCTOR) that allows accurate manual segmentation of OCT B-scans, and provides thickness/volume measurements of ICS, ONL, neurosensory retina, pigment epithelial detachments (PEDs), subretinal fluid (SRF) and subretinal tissue (SRT). Univariate and multivariate analyses were used to correlate OCT parameters with ...

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    1-25 of 25
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    Quantitative Analysis of Retinal Structures Using Spectral Domain Optical Coherence Tomography in Normal Rabbits OCT Angiography in Healthy Human Subjects Optical Coherence Tomography Angiography Optical Coherence Tomography Angiography of Diabetic Retinopathy in Human Subjects OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF RETINAL VENOUS OCCLUSION Quantifying Microvascular Density and Morphology in Diabetic Retinopathy Using Spectral-Domain Optical Coherence Tomography Angiography Quantifying Retinal Microvascular Changes in Uveitis Using Spectral-Domain Optical Coherence Tomography Angiography Quantitative microvascular analysis of retinal venous occlusions by spectral domain optical coherence tomography angiography The truth about invisible posterior vitreous structures Increased Macrophage-like Cell Density in Retinal Vein Occlusion as Characterized by en Face Optical Coherence Tomography The Influence of Eyelid Position and Environmental Conditions on the Corneal Changes in Early Postmortem Interval: A Prospective, Multicentric OCT Study The Use of Optical Coherence Tomography for Gross Examination and Sampling of Fixed Breast Specimens: A Pilot Study