1. Articles from Yali Jia

    1-24 of 123 1 2 3 4 5 6 »
    1. Automated detection of shadow artifacts in optical coherence tomography angiography

      Automated detection of shadow artifacts in optical coherence tomography angiography

      Disclosed herein are methods and systems for automated detection of shadow artifacts in optical coherence tomography (OCT) and/or OCT angiography (OCTA). The shadow detection includes applying a machine-learning algorithm to the OCT dataset and the OCTA dataset to detect one or more shadow artifacts in the sample. The machine-learning algorithm is trained with first training data from first training samples that include manufactured shadows and no perfusion defects and second training data from second training samples that include perfusion defects and no manufactured shadows. The shadow artifacts in the OCTA dataset and/or OCT dataset may be suppressed to ...

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    2. Peripheral OCT Assisted by Scleral Depression in Retinopathy of Prematurity

      Peripheral OCT Assisted by Scleral Depression in Retinopathy of Prematurity

      Objective: To determine whether handheld widefield optical coherence tomography (OCT) can be used to document retinopathy of prematurity (ROP) stage while using scleral depression to improve peripheral views. Design: Prospective observational study. Participants: Consecutive neonates admitted to the neonatal intensive care unit (NICU) in a single academic medical center who also met criteria for ROP screening and consented for research imaging. Methods: Scleral depression was combined with widefield OCT using an investigational 400-kHz, 55-degree field of view handheld OCT during routine ROP screening from October 28, 2020 to March 03, 2021. Main outcome measures: Acquisition of en face and B-scan ...

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    3. Advantages of Widefield Optical Coherence Tomography in the Diagnosis of Retinopathy of Prematurity

      Advantages of Widefield Optical Coherence Tomography in the Diagnosis of Retinopathy of Prematurity

      Recent advances in portable optical coherence tomography (OCT) and OCT angiography (OCTA) have resulted in wider fields of view (FOV) and shorter capture times, further expanding the potential clinical role of OCT technology in the diagnosis and management of retinopathy of prematurity (ROP). Using a prototype, handheld OCT device, retinal imaging was obtained in non-sedated infants in the neonatal intensive care unit (NICU) as well as sedated infants in the operating room of Oregon Health & Science University (OHSU) Hospital. In this observational study, we provide an overview of potential advantages of OCT-based disease assessment in ROP. We observed that next-generation ...

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    4. 105° field of view non-contact handheld swept-source optical coherence tomography

      105° field of view non-contact handheld swept-source optical coherence tomography

      We demonstrate a handheld swept-source optical coherence tomography (OCT) system with a 400 kHz vertical-cavity surface-emitting laser (VCSEL) light source, a non-contact approach, and an unprecedented single shot 105° field of view (FOV). We also implemented a spiral scanning pattern allowing real-time visualization with improved scanning efficiency. To the best of our knowledge, this is the widest FOV achieved in a portable non-contact OCT retinal imaging system to date. Improvements to the FOV may aid the evaluation of retinal diseases such as retinopathy of prematurity, where important vitreoretinal changes often occur in the peripheral retina.

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    5. Deep learning-based signal-independent assessment of macular avascular area on 6×6 mm optical coherence tomography angiogram in diabetic retinopathy: a comparison to instrument-embedded software

      Deep learning-based signal-independent assessment of macular avascular area on 6×6 mm optical coherence tomography angiogram in diabetic retinopathy: a comparison to instrument-embedded software

      Synopsis: A deep-learning-based macular extrafoveal avascular area (EAA) on a 6×6 mm optical coherence tomography (OCT) angiogram is less dependent on the signal strength and shadow artefacts, providing better diagnostic accuracy for diabetic retinopathy (DR) severity than the commercial software measured extrafoveal vessel density (EVD). Aims: To compare a deep-learning-based EAA to commercial output EVD in the diagnostic accuracy of determining DR severity levels from 6×6 mm OCT angiography (OCTA) scans. Methods: The 6×6 mm macular OCTA scans were acquired on one eye of each participant with a spectral-domain OCTA system. After excluding the central 1 mm ...

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    6. Optical coherence tomographic angiography study of perfusion recovery after surgical lowering of intraocular pressure

      Optical coherence tomographic angiography study of perfusion recovery after surgical lowering of intraocular pressure

      We investigated the time and location of retinal perfusion recovery after surgical intraocular pressure (IOP) lowering in glaucoma by using optical coherent tomography angiography (OCTA). Seventeen patients were analyzed. The 4.5 × 4.5-mm OCTA scans centered on the disc were performed preoperatively and postoperatively at 6 weeks, 3 months, and 6 months. The peripapillary retinal nerve fiber layer (NFL) thickness, NFL plexus capillary density (NFLP-CD) and visual field (VF) were measured overall and in 8 corresponding sectors. The low-perfusion area (LPA) was used to assess the cumulative area where local NFLP-CD was significantly below normal. At 6 months, the ...

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    7. Normative intercapillary distance and vessel density data in the temporal retina assessed by wide-field spectral-domain optical coherence tomography angiography

      Normative intercapillary distance and vessel density data in the temporal retina assessed by wide-field spectral-domain optical coherence tomography angiography

      A limitation of conventional optical coherence tomography angiography (OCTA) is the limited field of view normally used in data acquisition. As the technology improves, larger fields of view that capture information away from the macular are being explored in order to provide an enhanced ability to detect pathology. However, normative measurements for important OCTA metrics like vessel density and intercapillary distance are not currently well-characterized in the peripheral retina. In this prospective study, we measured vessel density and intercapillary distance of the superficial vascular complex, ganglion cell layer plexus, and deep capillary plexus in montaged macular/temporal scans from 53 ...

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    8. Effect of algorithms and covariates in glaucoma diagnosis with optical coherence tomography angiography

      Effect of algorithms and covariates in glaucoma diagnosis with optical coherence tomography angiography

      Purpose: To assess the effects of algorithms and covariates in glaucoma diagnosis with optical coherence tomography angiography (OCTA). Methods: In this prospective cross-sectional study, one eye each of 36 normal controls and 64 patients with glaucoma underwent 4.5 mm disc-centred and 6 mm macula-centred OCTA scans. The peripapillary nerve fibre layer plexus capillary density (NFLP-CD) and macular superficial vascular complex vessel density (SVC-VD) were measured using both a commercial algorithm (AngioAnalytics) and a custom algorithm (Center for Ophthalmic Optics & Lasers Angiography Reading Toolkit (COOL-ART)). The nerve fibre layer and ganglion cell complex thicknesses were measured on structural OCT. Results ...

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    9. DcardNet: Diabetic Retinopathy Classification at Multiple Levels Based on Structural and Angiographic Optical Coherence Tomography

      DcardNet: Diabetic Retinopathy Classification at Multiple Levels Based on Structural and Angiographic Optical Coherence Tomography

      Objective: Optical coherence tomography (OCT) and its angiography (OCTA) have several advantages for the early detection and diagnosis of diabetic retinopathy (DR). However, automated, complete DR classification frameworks based on both OCT and OCTA data have not been proposed. In this study, a convolutional neural network (CNN) based method is proposed to fulfill a DR classification framework using en face OCT and OCTA.

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    10. Cognitive decline in older adults: What can we learn from optical coherence tomography (OCT)-based retinal vascular imaging?

      Cognitive decline in older adults: What can we learn from optical coherence tomography (OCT)-based retinal vascular imaging?

      Introduction: Accumulated vascular damage contributes to the onset and progression of vascular dementia and possibly to Alzheimer's disease. Here we evaluate the feasibility and utility of using retinal imaging of microvascular markers to identify older adults at risk of cognitive disease. Methods: The "Eye Determinants of Cognition" (EyeDOC) study recruited a biracial, population-based sample of participants from two sites: Jackson, MS, and Washington Co, MD. Optical coherence tomographic angiography (OCTA) was used to capture vessel density (VD) from a 6 × 6 mm scan of the macula in several vascular layers from 2017 to 2019. The foveal avascular zone (FAZ ...

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    11. High-speed and widefield handheld swept-source OCT angiography with a VCSEL light source

      High-speed and widefield handheld swept-source OCT angiography with a VCSEL light source

      Optical coherence tomography (OCT) and OCT angiography (OCTA) enable noninvasive structural and angiographic imaging of the eye. Portable handheld OCT/OCTA systems are required for imaging patients in the supine position. Examples include infants in the neonatal intensive care unit (NICU) and operating room (OR). The speed of image acquisition plays a pivotal role in acquiring high-quality OCT/OCTA images, particularly with the handheld system, since both the operator hand tremor and subject motion can cause significant motion artifacts. In addition, having a large field of view and the ability of real-time data visualization are critical elements in rapid disease ...

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    12. Phase-stabilized complex-decorrelation angiography

      Phase-stabilized complex-decorrelation angiography

      In this study, we developed a novel phase-stabilized complex-decorrelation (PSCD) optical coherence tomography (OCT) angiography (OCTA) method that can generate high quality OCTA images. This method has been validated using three different types of OCT systems and compared with conventional complex- and amplitude-based OCTA algorithms. Our results suggest that in combination with a pre-processing phase stabilization method, the PSCD method is insensitive to bulk motion phase shifts, less dependent on OCT reflectance than conventional complex methods and demonstrates extended dynamic range of flow signal, in contrast to other two methods.

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    13. Comparison of Central Macular Fluid Volume With Central Subfield Thickness in Patients With Diabetic Macular Edema Using Optical Coherence Tomography Angiography

      Comparison of Central Macular Fluid Volume With Central Subfield Thickness in Patients With Diabetic Macular Edema Using Optical Coherence Tomography Angiography

      Importance: Diabetic macular edema (DME) is the predominant cause of visual impairment in patients with type 1 or 2 diabetes. Automated fluid volume measurements using optical coherence tomography (OCT) may improve the diagnostic accuracy of DME screening. Objective: To assess the diagnostic accuracy of an automated central macular fluid volume (CMFV) quantification using OCT for DME. Design, setting, and participants: A cross-sectional observational study was conducted at a tertiary academic center among 215 patients with diabetes (1 eye each) enrolled from January 26, 2015, to December 23, 2019. All participants underwent comprehensive examinations, 6 × 6-mm macular structural OCT horizontal raster ...

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    14. Plexus-specific retinal vascular anatomy and pathologies as seen by projection-resolved optical coherence tomographic angiography

      Plexus-specific retinal vascular anatomy and pathologies as seen by projection-resolved optical coherence tomographic angiography

      Optical coherence tomographic angiography (OCTA) is a novel technology capable of imaging retinal vasculature three-dimensionally at capillary scale without the need to inject any extrinsic dye contrast. However, projection artifacts cause superficial retinal vascular patterns to be duplicated in deeper layers, thus interfering with the clean visualization of some retinal plexuses and vascular pathologies. Projection-resolved OCTA (PR-OCTA) uses post-processing algorithms to reduce projection artifacts. With PR-OCTA, it is now possible to resolve up to 4 distinct retinal vascular plexuses in the living human eye. The technology also allows us to detect and distinguish between various retinal and optic nerve diseases ...

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    15. Plexus-specific retinal capillary avascular area in exudative age-related macular degeneration with projection-resolved OCT angiography

      Plexus-specific retinal capillary avascular area in exudative age-related macular degeneration with projection-resolved OCT angiography

      Objective To detect the plexus-specific retinal capillary avascular area in exudative age-related macular degeneration (EAMD) with projection-resolved optical coherence tomography angiography (PR-OCTA). Methods and analysis In this prospective cross-sectional single centre study, eyes with treatment-naïve EAMD underwent macular 3×3 mm OCTA with AngioVue system. OCTA scans were analysed and processed including three-dimensional projection artefact removal, retinal layer semi-automated segmentation and en face angiogram generation. Automated quantification of extrafoveal (excluding the central 1 mm circle) avascular area (EAA) were calculated on projection-resolved superficial vascular complex (SVC), intermediate capillary plexus (ICP) and deep capillary plexus (DCP), respectively. Results Nineteen eyes ...

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    16. Split-spectrum amplitude-decorrelation angiography with optical coherence tomography

      Split-spectrum amplitude-decorrelation angiography with optical coherence tomography

      Amplitude decorrelation measurement is sensitive to transverse flow and immune to phase noise in comparison to Doppler and other phase-based approaches. However, the high axial resolution of OCT makes it very sensitive to the pulsatile bulk motion noise in the axial direction. To overcome this limitation, we developed split-spectrum amplitude-decorrelation angiography (SSADA) to improve the signal-to-noise ratio (SNR) of flow detection. The full OCT spectrum was split into several narrower bands. Inter-B-scan decorrelation was computed using the spectral bands separately and then averaged. The SSADA algorithm was tested on in vivo images of the human macula and optic nerve head ...

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    17. Sensorless adaptive-optics optical coherence tomographic angiography

      Sensorless adaptive-optics optical coherence tomographic angiography

      Optical coherence tomographic angiography (OCTA) can image the retinal blood flow but visualization of the capillary caliber is limited by the low lateral resolution. Adaptive optics (AO) can be used to compensate ocular aberrations when using high numerical aperture (NA), and thus improve image resolution. However, previously reported AO-OCTA instruments were large and complex, and have a small sub-millimeter field of view (FOV) that hinders the extraction of biomarkers with clinical relevance. In this manuscript, we developed a sensorless AO-OCTA prototype with an intermediate numerical aperture to produce depth-resolved angiograms with high resolution and signal-to-noise ratio over a 2 × 2 ...

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    18. Automated segmentation of retinal fluid volumes from structural and angiographic optical coherence tomography using deep learning

      Automated segmentation of retinal fluid volumes from structural and angiographic optical coherence tomography using deep learning

      Purpose: We proposed a deep convolutional neural network (CNN), named Retinal Fluid Segmentation Network (ReF-Net) to segment volumetric retinal fluid on optical coherence tomography (OCT) volume. Methods: 3 × 3-mm OCT scans were acquired on one eye by a 70-kHz OCT commercial AngioVue system (RTVue-XR; Optovue, Inc.) from 51 participants in a clinical diabetic retinopathy (DR) study (45 with retinal edema and 6 healthy controls). A CNN with U-Net-like architecture was constructed to detect and segment the retinal fluid. Cross-sectional OCT and angiography (OCTA) scans were used for training and testing ReF-Net. The effect of including OCTA data for retinal fluid ...

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    19. Retinal capillary oximetry with visible light optical coherence tomography

      Retinal capillary oximetry with visible light optical coherence tomography

      Assessing oxygen saturation (sO 2 ) remains challenging but is nonetheless necessary for understanding retinal metabolism. We and others previously achieved oximetry on major retinal vessels and measured the total retinal oxygen metabolic rate in rats using visible-light optical coherence tomography. Here we extend oximetry measurements to capillaries and investigate all three retinal vascular plexuses by amplifying and extracting the spectroscopic signal from each capillary segment under the guidance of optical coherence tomography (OCT) angiography. Using this approach, we measured capillary sO 2 in the retinal circulation in rats, demonstrated reproducibility of the results, validated the measurements in superficial capillaries with ...

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    20. Depth-resolved optimization of a real-time sensorless adaptive optics optical coherence tomography

      Depth-resolved optimization of a real-time sensorless adaptive optics optical coherence tomography

      Sensorless adaptive optics optical coherence tomography (AO-OCT) is a technology to image retinal tissue with high resolution by compensating ocular aberrations without wavefront sensors. In this Letter, a fast and robust hill-climbing algorithm is developed to optimize five Zernike modes in AO-OCT with a numerical aperture between that of conventional AO and commercial OCT systems. The merit function is generated in real time using graphics processing unit while axially tracking the retinal layer of interest. A new method is proposed to estimate the largest achievable field of view for which aberrations are corrected uniformly in sensorless AO-OCT.

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    21. Optical coherence tomography angiography avascular area association with one-year treatment requirement and disease progression in diabetic retinopathy

      Optical coherence tomography angiography avascular area association with one-year treatment requirement and disease progression in diabetic retinopathy

      Purpose To assess the association between optical coherence tomography angiography (OCTA) quantified avascular areas (AA) and diabetic retinopathy (DR) severity, progression and treatment requirement in the following year. Design Prospective cohort study. Methods We recruited diabetic patients from tertiary academic retina practice and obtained 3x3-mm macular OCTA scans with AngioVue system and standard 7-field color photographs at baseline and 1-year visit. A masked grader determined the DR severity from the color photographs using the Early Treatment of Diabetic Retinopathy (ETDRS) scale. A custom algorithm detected extrafoveal AA (EAA) excluding the central 1mm circle in projection-resolved superficial vascular complex (SVC), intermediate ...

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    22. Systems and methods to remove shadowgraphic flow projections on OCT angiography

      Systems and methods to remove shadowgraphic flow projections on OCT angiography

      Methods and systems for suppressing shadowgraphic flow projection artifacts in OCT angiography images of a sample are disclosed. In one example approach, normalized OCT angiography data is analyzed at the level of individual A-scans to classify signals as either flow or projection artifact. This classification information is then used to suppress projection artifacts in the three dimensional OCT angiography dataset.

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    23. Imaging retinal structures at cellular-level resolution by visible-light optical coherence tomography

      Imaging retinal structures at cellular-level resolution by visible-light optical coherence tomography

      In vivo high-resolution images are the most direct way to understand retinal function and diseases. Here we report the use of visible-light optical coherence tomography with volumetric registration and averaging to achieve cellular-level retinal structural imaging in a rat eye, covering the entire depth of the retina. Vitreous fibers, nerve fiber bundles, and vasculature were clearly revealed, as well as at least three laminar sublayers in the inner plexiform layer. We also successfully visualized ganglion cell somas in the ganglion cell layer, cells in the inner nuclear layer, and photoreceptors in the outer nuclear layer and ellipsoid zone. This technique ...

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    24. Application of Corneal Optical Coherence Tomography Angiography for Assessment of Vessel Depth in Corneal Neovascularization

      Application of Corneal Optical Coherence Tomography Angiography for Assessment of Vessel Depth in Corneal Neovascularization

      Purpose: To map and measure the depths of corneal neovascularization (NV) using 3-dimensional optical coherence tomography angiography (OCTA) at 2 different wavelengths. Methods: Corneal NV of varying severity, distribution, and underlying etiology was examined. Average NV depth and vessel density were measured using 840-nm spectral-domain OCTA and 1050-nm swept-source OCTA. The OCTA results were compared with clinical slit-lamp estimation of NV depth. Results: Twelve eyes with corneal NV from 12 patients were imaged with OCTA. Clinically “superficial,” “midstromal,” and “deep” cases had an average vessel depth of 23%, 39%, and 66% on 1050-nm OCTA, respectively. Average vessel depth on OCTA ...

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