1. Articles from Khalil Ghasemi Falavarjani

    1-24 of 24
    1. Differentiating features of OCT angiography in diabetic macular edema

      Differentiating features of OCT angiography in diabetic macular edema

      The purpose of current study was to evaluate different optical coherence tomography angiography (OCTA) metrics in eyes with diabetic retinopathy with and without diabetic macular edema (DME). In this retrospective study, macular OCTA images of eyes with non-proliferative or proliferative diabetic retinopathy were evaluated. Vascular density, vascular complexity and non-perfusion densities were compared between eyes with and without DME. One-hundred-thirty-eight eyes of 92 diabetic patients including 49 eyes with DME were included. In multivariate analysis, the presence of DME was positively associated with geometric perfusion deficit (GPD) in superficial capillary plexus (SCP), capillary non-perfusion (CNP) of SCP, and GPD in ...

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    2. Artifacts in Optical Coherence Tomography Angiography

      Artifacts in Optical Coherence Tomography Angiography

      We performed a comprehensive search of the published literature in PubMed and Google Scholar to identify types, prevalence, etiology, clinical impact, and current methods for correction of various artifacts in optical coherence tomography angiography (OCTA) images. We found that the prevalence of OCTA image artifacts is fairly high. Artifacts associated with eye motion, misidentification of retinal layers, projections, and low optical coherence tomography signal are the most prevalent types. Artifacts in OCTA images are the major limitations of this diagnostic modality in clinical practice and identification of these artifacts and measures to mitigate them are essential for correct diagnosis and ...

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    3. Optical coherence tomography angiography and structural analyses of the pale optic discs: is it possible to differentiate the cause?

      Optical coherence tomography angiography and structural analyses of the pale optic discs: is it possible to differentiate the cause?

      Introduction: To compare the optic nerve head (ONH) structure and microvasculature in patients with optic atrophy due to non-arteritic anterior ischemic optic neuropathy (NAION), compressive optic neuropathy (CON), methanol-induced optic neuropathy (MION), and traumatic optic neuropathy (TON) using optical coherence tomography angiography. Methods: In this comparative, cross-sectional study, 32 eyes with NAION, 18 eyes with CON, 32 eyes with MION, 23 eyes with TON, and 55 normal eyes were enrolled. Radial peripapillary capillary (RPC) vessel density, peripapillary retinal nerve fiber layer (RNFL) thickness, disc area, cup volume, and cup/disc area ratio were obtained using the RTVue XR Avanti system ...

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      Mentions: Visionix
    4. The effect of intravitreal recombinant tissue plasminogen activator injection on diabetic tractional fibrovascular membranes: Proposed criteria using optical coherence tomography

      The effect of intravitreal recombinant tissue plasminogen activator injection on diabetic tractional fibrovascular membranes: Proposed criteria using optical coherence tomography

      Purpose: To evaluate the effect of intravitreal recombinant tissue plasminogen activator (tPA) on diabetic tractional fibrovascular membranes (FVM) using proposed optical coherence tomography (OCT) criteria. Methods: This prospective, interventional case series enrolled eyes with tractional retinal detachment who were candidates for pars plana vitrectomy. OCT images were obtained to evaluate the border of the attached-detached retina and overlying FVP at baseline and 1 week post-intravitreal tPA injection using the follow-up scan acquisition protocol. Two independent graders assessed retinal detachment (RD) height, FVM height, and retinal thickness at the site of membrane attachment. Results: Thirteen eyes from 13 individuals were included ...

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    5. Foveal avascular zone segmentation in optical coherence tomography angiography images using a deep learning approach

      Foveal avascular zone segmentation in optical coherence tomography angiography images using a deep learning approach

      The purpose of this study was to introduce a new deep learning (DL) model for segmentation of the fovea avascular zone (FAZ) in en face optical coherence tomography angiography (OCTA) and compare the results with those of the device’s built-in software and manual measurements in healthy subjects and diabetic patients. In this retrospective study, FAZ borders were delineated in the inner retinal slab of 3 × 3 enface OCTA images of 131 eyes of 88 diabetic patients and 32 eyes of 18 healthy subjects. To train a deep convolutional neural network (CNN) model, 126 enface OCTA images (104 eyes with ...

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    6. Comparison of Superficial and Deep Foveal Avascular Zone Area in Healthy Subjects Using Two Spectral Domain Optical Coherence Tomography Angiography Devices

      Comparison of Superficial and Deep Foveal Avascular Zone Area in Healthy Subjects Using Two Spectral Domain Optical Coherence Tomography Angiography Devices

      Purpose: To compare the area of the foveal avascular zone (FAZ) in the superficial and deep retinal layers using two different spectral-domain optical coherence tomography angiography (OCTA) devices. Methods: A cross-sectional comparative study was conducted to obtain macular OCTA images from healthy subjects using Optovue RTVue XR Avanti (Optovue, Inc, Fremont, CA) and Spectralis HRA+OCTA (Heidelberg Engineering, Heidelberg, Germany). Two independent trained graders measured the FAZ area using automated slab segmentation. The FAZ area in the superficial and deep retinal layers were compared. Results: Twenty-three eyes of 23 subjects were included. The graders agreement was excellent (>0.86) for ...

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    7. Quantitative analysis of optical coherence tomography angiography metrics in diabetic retinopathy

      Quantitative analysis of optical coherence tomography angiography metrics in diabetic retinopathy

      Purpose: To evaluate the correlation of the visual acuity and diabetic retinopathy stage using optical coherence tomography and optical coherence tomography angiography metrics. Methods: In this prospective study, optical coherence tomography and optical coherence tomography angiography images of patients with different stages of diabetic retinopathy were obtained. In optical coherence tomography angiography images, the size of foveal avascular zone, central macular thickness, and vessel density at superficial and deep capillary layers of the macula were measured. In optical coherence tomography images, the presence of intraretinal cyst, disorganization of retinal inner layer, and ellipsoid zone and external limiting membrane disruption were ...

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    8. Stepwise segmentation error correction in optical coherence tomography angiography images of patients with diabetic macular edema

      Stepwise segmentation error correction in optical coherence tomography angiography images of patients with diabetic macular edema

      Aim: To determine the minimum number of optical coherence tomography B-scan corrections required to provide acceptable vessel density measurements on optical coherence tomography angiography images in eyes with diabetic macular edema. Methods: In this prospective, noninterventional case series, the optical coherence tomography angiography images of eyes with center-involving diabetic macular edema were assessed. Optical coherence tomography angiography imaging was performed using RTVue Avanti spectral-domain optical coherence tomography system with the AngioVue software (V.2017.1.0.151; Optovue, Fremont, CA, USA). Segmentation error was recorded and manually corrected in the inner retinal layers in the central foveal, 100th and 200th ...

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      Mentions: Visionix
    9. Optical coherence tomography angiography (OCTA) applications in ocular oncology

      Optical coherence tomography angiography (OCTA) applications in ocular oncology

      Optical coherence tomography angiography (OCTA) is a revolutionary method in the visualization of the vascular system in different retinal and choroidal layers. During the last 4 years since the commercial availability of different OCTA devices, attempts have been made to utilize this technology in various aspects of ocular oncology from the differentiation of benign and malignant lesions to assisting in evaluation of post-treatment complications, such as radiation retinopathy. However, current OCTA technology is restricted by various artefacts and inherent limitations, some of which are more pronounced in the presence of elevated tumoural lesions. Imminent advancements in OCTA systems and image ...

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    10. Choroidal thickness and the retinal ganglion cell complex in chronic Leberʼs hereditary optic neuropathy: a prospective study using swept-source optical coherence tomography

      Choroidal thickness and the retinal ganglion cell complex in chronic Leberʼs hereditary optic neuropathy: a prospective study using swept-source optical coherence tomography

      Background/Objectives Choroidal thinning has been suggested in Leber’s hereditary optic neuropathy (LHON). No study has been conducted of the choroid in relation to the retinal ganglion cell-inner plexiform layer (RGC-IPL). We sought to measure choroidal thickness in chronic LHON and to correlate thickness changes with the RGC-IPL. Subjects/Methods Chronic LHON, 11778 mitochondrial DNA (mtDNA) mutation, patients (26 eyes; mean age: 35.1 ± 16.1 years) were prospectively recruited at Doheny Eye Center, University of California Los Angeles from March 2016 to July 2017. Age-matched healthy controls (27 eyes; mean age: 32.4 ± 11.1 years) were enroled ...

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    11. En Face OCT of Type 2 Neovascularization:A Reappraisal of the Pitchfork Sign

      En Face OCT of Type 2 Neovascularization:A Reappraisal of the Pitchfork Sign

      To describe a new en face optical coherence tomography (OCT) imaging feature of type 2 choroidal neovascularization (CNV) and illustrate the OCT angiographic (OCTA) findings in these eyes. PATIENTS AND METHODS: Multimodal images of patients with type 2 CNV who displayed the typical “pitchfork” sign with cross-sectional OCT were reviewed. Corresponding en face structural OCT and OCTA images were analyzed to correlate the finding before and after anti-vascular endothelial growth factor (VEGF) therapy. RESULTS: Five eyes of five patients, including two females and three males with a median age of 13 years (range: 8 years to 84 years), were studied ...

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    12. Effect of segmentation error correction on optical coherence tomography angiography measurements in healthy subjects and diabetic macular oedema

      Effect of segmentation error correction on optical coherence tomography angiography measurements in healthy subjects and diabetic macular oedema

      Purpose To evaluate the impact of segmentation error on vessel density measurements in healthy eyes and eyes with diabetic macular oedema (DMO). Methods In this prospective, comparative, non-interventional study, enface optical coherence tomography angiography (OCTA) images of the macula from healthy eyes and eyes with DMO were acquired. Two expert graders assessed and corrected the segmentation error. The rate of segmentation error and the changes in vessel density and inner retinal thickness after correction of the segmentation error were recorded and compared between the two groups. Results 20 eyes with DMO and 24 healthy eyes were evaluated. Intergrader agreement was ...

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      Mentions: UCLA
    13. Optical coherence tomography angiography features of optic nerve head drusen and nonarteritic anterior ischemic optic neuropathy

      Optical coherence tomography angiography features of optic nerve head drusen and nonarteritic anterior ischemic optic neuropathy

      Objective To evaluate the optic disc microvasculature in optic nerve head drusen (ONHD) vasculature in comparison to acute nonarteritic anterior ischemic optic neuropathy (NAION) and normal eyes using optical coherence tomography angiography (OCT-A). Methods Ten eyes with ONHD, 10 eyes with acute NAION, and 10 healthy eyes were included in this prospective, comparative, observational case series. OCT-A imaging was performed on the optic discs. Qualitative grading was performed for dilation and tortuosity of the peripapillary vessels by 3 graders. Quantitative comparison was performed for peripapillary and inside disc vessel densities in nerve head (NH) and retinal peripapillary capillary (RPC) slabs ...

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    14. Foveal avascular zone and vessel density in healthy subjects: An optical coherence tomography angiography study

      Foveal avascular zone and vessel density in healthy subjects: An optical coherence tomography angiography study

      Purpose: To report the normal characteristics and correlations of the foveal microvascular networks using optical coherence tomography angiography (OCTA) in a healthy Iranian population. Methods: Enface 3x3 OCTA images were obtained using the RTVue Avanti spectral-domain optical coherence tomography with AngioVue software (Optovue, Fremont, CA, USA). Foveal avascular zone (FAZ) area, central foveal point thickness and inner retinal thickness at the foveal center and the vascular density of the superficial retinal capillary plexus (SCP) and deep retinal capillary plexus (DCP) in the fovea were recorded. Results: Seventy normal eyes of 70 subjects (range, 9 to 71 years) were studied. Mean ...

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      Mentions: Visionix
    15. Optical Coherence Tomography Angiography of the Macula in Adults With a History of Preterm Birth

      Optical Coherence Tomography Angiography of the Macula in Adults With a History of Preterm Birth

      BACKGROUND AND OBJECTIVE: To evaluate the fovea microvasculature in adult subjects with history of preterm birth using optical coherence angiography (OCTA). PATIENTS AND METHODS: In this retrospective study, macular OCTA images were obtained from adult subjects with a history of preterm birth. The presence of the foveal avascular zone (FAZ) and its size was determined. RESULTS: Ten eyes from six subjects with ages ranging from 26 years old to 65 years old were evaluated. A distinct FAZ was not observed in three eyes (30%). The FAZ was small in other eyes, ranging from 0.07 mm 2 to 0.18 ...

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    16. Quantitative Features of the Choriocapillaris in Healthy Individuals Using Swept-Source Optical Coherence Tomography Angiography

      Quantitative Features of the Choriocapillaris in Healthy Individuals Using Swept-Source Optical Coherence Tomography Angiography

      BACKGROUND AND OBJECTIVE: To quantify vessel density (VD) and grey value (GV) as a measure of flow in the choriocapillaris (CC) in healthy subjects with optical coherence tomography angiography (OCTA). PATIENTS AND METHODS: In this prospective, noncomparative case series, 3 mm × 3 mm OCTA images of 36 eyes of 22 healthy individuals were obtained using a swept-source instrument. VD and GV levels were calculated on CC en face slabs in the central 1-mm (subfoveal field) and surrounding 2.5-mm parafoveal ring. VD was calculated as a ratio of vessel area over nonvessel area following image binarization. GV was computed as ...

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    17. Optical coherence tomography angiography of the retina and choroid; current applications and future directions

      Optical coherence tomography angiography of the retina and choroid; current applications and future directions

      Dye-based angiography has been the standard of care for the diagnosis of retinal, choroidal and optic nerve vascular disorders for a long period of time. Since its introduction in 1961, angiography techniques and instrumentation have remarkably improved. 1 These advancements include, but are not limited to, the development of confocal scanning laser ophthalmoscopy, digital angiography, and wide-field imaging techniques. However, dye-based angiography remains a time-consuming, invasive procedure that requires skilled photographers. In addition, the images have limited depth resolution. Recently, a novel imaging strategy, optical coherence tomography angiography (OCTA) has been introduced. OCTA is a noninvasive modality for vascular mapping ...

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      Mentions: UCLA
    18. En Face OCT Analysis to Assess the Spectrum of Perivenular Ischemia and Paracentral Acute Middle Maculopathy in Retinal Vein Occlusion

      En Face OCT Analysis to Assess the Spectrum of Perivenular Ischemia and Paracentral Acute Middle Maculopathy in Retinal Vein Occlusion

      Purpose To assess the spectrum of perivenular ischemia in eyes with retinal vascular obstruction (typically central or hemicentral retinal vein obstruction) using en face optical coherence tomography (OCT). Design Retrospective observational case series. Methods Eyes with recent retinal vascular occlusion illustrating paracentral acute middle maculopathy (PAMM) in a perivenular fern-like pattern with en face OCT were evaluated in this study. Multimodal retinal imaging including en face OCT segmentation of the inner nuclear layer was performed in all patients. Color fundus photography and fluorescein angiography (FA) images were used to create a vascular overlay of the retinal veins versus the retinal ...

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    19. Optical coherence tomography angiography of the optic disc; an overview

      Optical coherence tomography angiography of the optic disc; an overview

      Different diseases of the optic disc may be caused by or lead to abnormal vasculature at the optic nerve head. Optical coherence tomography angiography (OCTA) is a novel technology that provides high resolution mapping of the retinal and optic disc vessels. Recent studies have shown the ability of OCTA to visualize vascular abnormalities in different optic neuropathies. In addition, quantified OCTA measurements were found promising for differentiating optic neuropathies from healthy eyes.

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    20. Optical Coherence Tomography Angiography Analysis of the Foveal Avascular Zone and Macular Vessel Density After Anti-VEGF Therapy in Eyes With Diabetic Macular Edema and Retinal Vein Occlusion

      Optical Coherence Tomography Angiography Analysis of the Foveal Avascular Zone and Macular Vessel Density After Anti-VEGF Therapy in Eyes With Diabetic Macular Edema and Retinal Vein Occlusion

      Purpose : To evaluate the changes in foveal avascular zone (FAZ) area and the retinal capillary density after a single intravitreal anti-VEGF injection for macular edema secondary to diabetic retinopathy or retinal vein occlusion. Methods : In this prospective noncomparative case series, 18 eyes of 15 patients with diabetic macular edema (13 eyes) or macular edema secondary to central retinal vein occlusion (5 eyes) were included. Optical coherence tomography angiography (OCTA) images were obtained, and retinal capillary vessel density and FAZ area were measured in the foveal and parafoveal regions at the level of the superficial (SCP) and deep retinal capillary plexus ...

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    21. Retinal vessel calibre measurements by optical coherence tomography angiography

      Retinal vessel calibre measurements by optical coherence tomography angiography

      Purpose To compare the vessel calibre measurements between optical coherence tomography angiography (OCTA) and colour fundus photography. Methods In this retrospective comparative study, OCTA and colour fundus images of healthy eyes and eyes with optic atrophy were evaluated. The colour fundus image was registered manually using Image J software to the OCTA image of the optic disc. Two independent graders measured the vessel calibre of the widest vein and artery in each peripapillary quadrant on a 3.4 mm diameter circle centred on the optic disc in the same location on both images. The difference in vessel calibre between the ...

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    22. Image artefacts in swept-source optical coherence tomography angiography

      Image artefacts in swept-source optical coherence tomography angiography

      Purpose To describe optical coherence tomography angiography (OCTA) image artefacts in eyes with and without ocular pathologies. Methods The OCTA images of healthy subjects and patients with age-related macular degeneration, diabetic retinopathy and retinal vascular occlusions were retrospectively reviewed. All OCTA images were obtained using a swept-source OCTA instrument (Triton, Topcon). The frequency of various image artefacts including segmentation, banding, motion, projection, masking, unmasking, doubling of the retinal vessels, blink, stretching, out-of-window and crisscross artefacts was assessed. The impact of the artefact on the grading of the images for the foveal avascular zone in deep and superficial retinal layers, capillary ...

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    23. Effect of Spectral Domain Optical Coherence Tomography Image Quality on Macular Thickness Measurements and Error Rate

      Effect of Spectral Domain Optical Coherence Tomography Image Quality on Macular Thickness Measurements and Error Rate

      Purpose : To evaluate the effect of Topcon spectral domain optical coherence tomography (OCT) image quality on macular thickness measurements and the error rate in healthy subjects and patients with clinically significant diabetic macular edema (CSME). Methods : In this prospective, comparative case series, macular thickness measurements, and the rate of decentration and segmentation errors were evaluated before and after reducing the image quality factor (QF). The measurements were evaluated again after correcting the decentration and segmentation errors. To reduce the image QF below 45, tetracycline eye ointment was applied on the corneal surface. Results : Forty eyes of 40 subjects including 18 ...

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    24. Detection of optic disc oedema using optical coherence tomography

      Detection of optic disc oedema using optical coherence tomography

      We read with great interest the study by Vartin C and associates,1 describing the role of spectral domain optical coherence tomography (OCT) for the detection of optic disc oedema. Currently, the standard method for the diagnosis of disc oedema is fundus examination. Obviously, the detection of moderate to severe disc oedema is easy. Patients with small cupless discs (so-called crowded discs) may have a prominent optic nerve head which looks like a mild disc oedema. In this subset of patients, the differentiation of oedematous from non-oedematous discs is problematic, and at this time, the ancillary test may be helpful ...

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    Detection of optic disc oedema using optical coherence tomography Effect of Spectral Domain Optical Coherence Tomography Image Quality on Macular Thickness Measurements and Error Rate Image artefacts in swept-source optical coherence tomography angiography Retinal vessel calibre measurements by optical coherence tomography angiography Optical Coherence Tomography Angiography Analysis of the Foveal Avascular Zone and Macular Vessel Density After Anti-VEGF Therapy in Eyes With Diabetic Macular Edema and Retinal Vein Occlusion Optical coherence tomography angiography of the optic disc; an overview En Face OCT Analysis to Assess the Spectrum of Perivenular Ischemia and Paracentral Acute Middle Maculopathy in Retinal Vein Occlusion Optical coherence tomography angiography of the retina and choroid; current applications and future directions Quantitative Features of the Choriocapillaris in Healthy Individuals Using Swept-Source Optical Coherence Tomography Angiography Optical Coherence Tomography Angiography of the Macula in Adults With a History of Preterm Birth New insights from non-invasive imaging: from prospection of skin photodamages to training with mobile application Short-sighted woman assumes debilitating headaches mean she needs new glasses but discovers she has multiple sclerosis