1. 1-24 of 1620 1 2 3 4 ... 66 67 68 »
    1. Revealing how maltodextrin-containing droplets dry using optical coherence tomography

      Revealing how maltodextrin-containing droplets dry using optical coherence tomography

      Properties of powders produced from drying solute-containing droplets arise from the dynamic redistribution of solute during drying. While insights on the dynamic redistribution are instrumental for the rational design of powders and for the optimized operation of equipment such as spray dryers, experimental techniques that allow measuring the spatio-temporal concentration of solute in drying droplets are scarce. In this work, we explore and demonstrate the use of optical coherence tomography (OCT) to measure the spatio-temporal concentration of solute in drying droplets and the development of a solidifying shell at the liquid-air interface, using aqueous droplets of maltodextrin as a model ...

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    2. Volume Rendering of Deep Retinal Age-Related Microvascular Anomalies

      Volume Rendering of Deep Retinal Age-Related Microvascular Anomalies

      Purpose To characterize and distinguish non-neovascular deep retinal age-related microvascular anomalies (DRAMA) from type 3 macular neovascularization (MNV) using volume rendering of optical coherence tomography (OCT) and OCT angiography (OCTA). Design Retrospective, consecutive case series. Subjects Consecutive patients with age-related macular degeneration (AMD) exhibiting de novo non-neovascular abnormalities within the deep vascular plexus (DCP) on high-resolution (High-Res) spectral domain and swept-source OCT/OCTA. Patients with retinal vascular alterations attributable to other disease entities were excluded. Methods Complete ophthalmologic examination and multimodal imaging including confocal fundus photography (CFP), spectral domain OCT (SD-OCT), High-Res SD-OCT and OCTA, and volume-averaged swept-source OCTA (SS-OCTA ...

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    3. Treatment of Descemet's membrane detachment after primary Descemet's stripping automated endothelial keratoplasty during surgery using intraoperative optical coherence tomography

      Treatment of Descemet's membrane detachment after primary Descemet's stripping automated endothelial keratoplasty during surgery using intraoperative optical coherence tomography

      Purpose: To present a novel microscope-integrated optical coherence tomography (iOCT)-guided surgical technique wherein Descemet's membrane detachment (DMD), occurring during vitrectomy, was treated intraoperatively in a patient who had previously undergone Descemet's stripping automated endothelial keratoplasty (DSAEK). Observations: The surgical technique was performed on a 75-year-old man with a history of DSAEK to intraoperatively treat DMD, which occurred during vitrectomy in the left eye. A fine needle mounted on a syringe was inserted into the supra-Descemet's space under iOCT guidance. The location of the needle was easily identified by its high reflection. The interface fluid was safely ...

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      Mentions: Osaka University
    4. Dynamic full-field optical coherence tomography as complementary tool in fungal diagnostics

      Dynamic full-field optical coherence tomography as complementary tool in fungal diagnostics

      Histopathology and microscopic examination of infected tissue are the gold standards to prove the diagnosis of invasive fungal infection (IFI). Yet, they suffer from essential limitations that hamper rapid diagnosis and require the future development of new imaging tools dedicated to fungal diagnostics. To this end, the present work introduces the first use of dynamic full-field optical coherence tomography (D-FF-OCT) for the visualization of microscopic filamentous fungi. Data collected from the observation of three different fungal species (Nannizzia gypsea, Aspergillus fumigatus and Rhizopus arrhizus) confirm the ability of D-FF-OCT to visualize not only the main structures of all selected fungal ...

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    5. Volumetric quantification of choroid and Haller's sublayer using OCT scans: An accurate and unified approach based on stratified smoothing

      Volumetric quantification of choroid and Haller's sublayer using OCT scans: An accurate and unified approach based on stratified smoothing

      Background and objective: The choroid, a dense vascular structure in the posterior segment of the eye, maintains the health of the retina by supplying oxygen and nutrients, and assumes clinical significance in screening ocular diseases including age-related macular degeneration (AMD) and central serous chorioretinopathy (CSCR). As a technological assist, algorithmic estimation of choroidal biomarkers has been suggested based on sectional (B-scan) optical coherence tomography (OCT) images. However, most such 2D estimation techniques are compute-intensive, yet enjoy limited accuracy and have only been validated on OCT image datasets of healthy eyes. Not surprisingly, fine-scale analyses, including those involving Haller's sublayer ...

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    6. Attention to region: Region-based integration-and-recalibration networks for nuclear cataract classification using AS-OCT images

      Attention to region: Region-based integration-and-recalibration networks for nuclear cataract classification using AS-OCT images

      Nuclear cataract (NC) is a leading eye disease for blindness and vision impairment globally. Accurate and objective NC grading/classification is essential for clinically early intervention and cataract surgery planning. Anterior segment optical coherence tomography (AS-OCT) images are capable of capturing the nucleus region clearly and measuring the opacity of NC quantitatively. Recently, clinical research has suggested that the opacity correlation and repeatability between NC severity levels and the average nucleus density on AS-OCT images is high with the interclass and intraclass analysis. Moreover, clinical research has suggested that opacity distribution is uneven on the nucleus region, indicating that the ...

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    7. Ozone-induced retinal vascular reactivity as assessed by optical coherence tomography angiography

      Ozone-induced retinal vascular reactivity as assessed by optical coherence tomography angiography

      Background: This study aimed to investigate the retinal vascular reactivity (RVR) of the macular and peripapillary capillary network in response to ozonated autohemotherapy (AHT) using optical coherence tomography angiography (OCTA). Methods: This was a single-centre prospective study. All participants that were planned to have a combination of major and minor ozone AHT underwent a complete ocular examination and OCTA imaging before and after the ozone AHT. Foveal avascular zone (FAZ) metrics and vessel density (VD) of superficial (SCP), deep capillary plexus (DCP), and radial peripapillary capillary (RPC) plexus were assessed using the built-in software. Results: A total of 40 right ...

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    8. The effect of pegcetacoplan treatment on photoreceptor maintenance in geographic atrophy monitored by AI-based OCT analysis

      The effect of pegcetacoplan treatment on photoreceptor maintenance in geographic atrophy monitored by AI-based OCT analysis

      Purpose: To investigate the therapeutic effect of intravitreal pegcetacoplan on the inhibition of photoreceptor (PR) loss and thinning in geographic atrophy (GA) on conventional spectral domain-optical coherence tomography (SD-OCT) imaging by deep learning-based automated PR quantification. Design: Post-hoc analysis of a prospective, multicenter, randomized, sham-controlled, masked phase II trial investigating the safety and efficacy of pegcetacoplan for the treatment of GA due to age-related macular degeneration. Participants: Study eyes of 246 patients, randomized 1:1:1 to monthly (AM), bimonthly (AEOM) and sham (SM) treatment. Methods: We performed fully automated, deep learning-based segmentation of retinal pigment epithelium (RPE) loss and ...

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    9. Deep Capillary Geometric Perfusion Deficits on OCT Angiography Detect Clinically Referable Eyes with Diabetic Retinopathy

      Deep Capillary Geometric Perfusion Deficits on OCT Angiography Detect Clinically Referable Eyes with Diabetic Retinopathy

      Purpose: To evaluate the sensitivity (SN) and specificity (SP) of optical coherence tomography angiography (OCTA) parameters for detecting clinically referable eyes with diabetic retinopathy (DR) in a cohort of patients with diabetes mellitus (DM). Design: Retrospective, cross-sectional study. Subjects: Patients with DM with various levels of DR. Methods: We measured vessel density, vessel length density (VLD), and geometric perfusion deficits (GPD) in the full retina, superficial (SCP) and deep capillary plexus (DCP) on 3 x 3 mm OCTA images. GPD was recently described as retinal tissue located further than 30 μm from blood vessels, excluding the foveal avascular zone (FAZ ...

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    10. Effect of caffeine on superficial retinal vasculature of the macula in high myopes using optical coherence tomography angiography - A pilot study

      Effect of caffeine on superficial retinal vasculature of the macula in high myopes using optical coherence tomography angiography - A pilot study

      Purpose: To monitor effect of caffeine on vasculature of the inner retina of high myopes METHODS: This was a crossover, self-control, randomized trial. Healthy young high myopes were recruited to take 200 mg of caffeine capsule and placebo capsule, randomly assigned in two visits separated by at least one week. Superficial retinal vasculature in terms of vessel length density (VD) and perfusion area density (PD) was captured and monitored using a spectral domain optical coherence tomography angiography (OCTA) machine. After baseline measurements, blood pressure (BP), intraocular pressure (IOP), and subfoveal choroidal thickness (ChT) were also monitored at 30-min intervals till ...

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    11. Analysis of optic disc tilt angle in intrapapillary hemorrhage adjacent to peripapillary subretinal hemorrhage using swept-source optical coherence tomography

      Analysis of optic disc tilt angle in intrapapillary hemorrhage adjacent to peripapillary subretinal hemorrhage using swept-source optical coherence tomography

      Purpose: To report findings on the tilt angle of optic nerve heads (ONHs) that developed intrapapillary hemorrhage with adjacent peripapillary subretinal hemorrhage (IHAPSH) using swept-source optical coherence tomography (SS-OCT). Observations: Five consecutive patients who presented with IHAPSH were reviewed retrospectively. We reviewed five consecutive eyes from the five patients, analyzed the optic tilt angle obtained from SS-OCT B-scans, and compared the results and other clinical characteristics. All patients had larger optic disc tilt angles in the eyes with IHAPSH than in the contralateral, unaffected eye. The mean ratio of the tilt angle in the eyes with IHAPSH to that in ...

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      Mentions: Osaka University
    12. PIPE-Net: A pyramidal-input-parallel-encoding network for the segmentation of corneal layer interfaces in OCT images

      PIPE-Net: A pyramidal-input-parallel-encoding network for the segmentation of corneal layer interfaces in OCT images

      Segmentation of corneal layer interfaces in optical coherence tomography (OCT) images is necessary to generate thickness maps used for cornea diagnosis. In this paper, we propose PIPE-Net, a fully convolutional neural network with a pyramidal input, parallel encoders, and a densely connected decoder to segment four corneal layer interfaces. The pyramidal input is encoded using parallel encoders, which allows the network to process a larger receptive field. The encoders are connected level-wise to the decoder through residual summations. The decoder is densely connected using residual summations between its levels to enhance the gradient flow. We use a linear growth rate ...

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    13. Comparing Optical Coherence Tomography and Intravascular Ultrasound Guidance for Percutaneous Coronary Intervention

      Comparing Optical Coherence Tomography and Intravascular Ultrasound Guidance for Percutaneous Coronary Intervention

      Background: Optical coherence tomography (OCT) and intravascular ultrasound (IVUS) optimize percutaneous coronary intervention (PCI) by characterizing lesion morphology, accurately measuring vessel dimensions, and optimizing stent characteristics. We sought to compare the utilization of OCT and IVUS to guide inpatient PCI and their relative association with in-hospital mortality and readmission rates. Methods: We queried the National Readmission Database to identify patients undergoing intracoronary imaging-guided PCI from 2010 to 2019 and compared outcomes and readmission rates between patients undergoing OCT-guided PCI and IVUS-guided PCI. Multivariable logistic regression was performed to generate adjusted odds ratios (aOR) of adverse outcomes between the 2 groups ...

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    14. Ex-vivo evaluation of miniaturized probes for endoscopic optical coherence tomography in urothelial cancer diagnostics

      Ex-vivo evaluation of miniaturized probes for endoscopic optical coherence tomography in urothelial cancer diagnostics

      Background: The gold standard for detecting bladder cancer is white light cystoscopy (WLC) and resection of suspicious lesions. In this study, we evaluate two miniaturized Optical Coherence Tomography (OCT) probes for endoscopic use, regarding their applicability in diagnosing urothelial cancer. Materials and methods: In total, 33 patients who underwent a radical cystectomy were included. Preoperative oncological staging and determining the indication for the surgical intervention were done following the latest European Association of Urology (EAU) guidelines. Samples were taken from bladder tissue after bladder removal and prepared for OCT measurement. Additionally, porcine bladder samples were used as reference tissue. We ...

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    15. Effects of microplastics on lentil (Lens culinaris) seed germination and seedling growth

      Effects of microplastics on lentil (Lens culinaris) seed germination and seedling growth

      Widespread use of plastics and mishandling has resulted in severe environmental issues affecting seed germination and seedling growth. This study investigates the effect of polyethylene microplastics (740–4990 nm PEMPs) on lentil ( Lens culinaris ) seed germination and seedling growth using Biospeckle Optical Coherence Tomography (bOCT), a technique that we successfully demonstrated earlier in visualizing the internal activity of plants. Lentil seeds were exposed to PEMPs bioassay for seven days with 10, 50, and 100 mg L −1 concentrations. The average speckle contrast was calculated after 0 h, 6 h, 12 h, and 24 h of exposure, and statistically significant differences ...

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    16. Current limitations and future of optical coherence tomography angiography

      Current limitations and future of optical coherence tomography angiography

      For flow signal detection, OCTA protocols scan the same retinal region several times using dense patterns 1 . This requires much higher scanning speeds (high number of A-scans per second) to achieve optimal acquisition time in daily clinical practice. In recent years there has been a trend to increase the acquisition speed, but work is also continuing to expand the scanning area in the various devices on the market. Some articles have shown imaging in larger scan areas with great utility in

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    17. Acute Effect of Hyperbaric Oxygen Therapy on Macular and Choroidal Thickness in Patients with Type 2 Diabetes and Diabetic Foot Ulcers: Optical Coherence Tomography Based Study

      Acute Effect of Hyperbaric Oxygen Therapy on Macular and Choroidal Thickness in Patients with Type 2 Diabetes and Diabetic Foot Ulcers: Optical Coherence Tomography Based Study

      Purpose: To evaluate the acute effect of hyperbaric oxygen therapy (HBOT) on central macular thickness (CMT) and choroidal thickness (CT) in patients with type 2 diabetes mellitus (T2D) undergoing HBOT due to diabetic foot ulcer (DFU). Methods: For this cross-sectional study, patients with T2D were recruited between May 2019 and June 2020. Only eyes with non-proliferative or no diabetic retinopathy (DR) were included. CMT and subfoveal, nasal, and temporal CT values measured by spectral-domain optical coherence tomography (Nidek RS-3000 Advance, Aichi, Japan) before and 45 minutes after the first HBOT session were compared between eyes with and without DR and ...

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      Mentions: Nidek
    18. Preclinical ocular microvascular changes in juvenile dermatomyositis: A pilot optical coherence tomography angiography study

      Preclinical ocular microvascular changes in juvenile dermatomyositis: A pilot optical coherence tomography angiography study

      Objectives To evaluate the macular and optic nerve head (ONH) vascular density, foveal avascular zone area, and outer retina and choriocapillaris flow in juvenile dermatomyositis (JDM) using optical coherence tomography angiography (OCTA). Methods Ten eyes of 10 patients with JDM and 15 age and sex-matched healthy controls were investigated in this prospective, cross-sectional study. The superficial capillary plexus (SCP) and deep capillary plexus (DCP), ONH, foveal avascular zone (FAZ) parameters, the flow area of the outer retina, and choriocapillaris were evaluated using OCTA. Results Vessel density (VD) of the parafovea ( p = 0.036) and parafoveal subregions ( p = 0.041 for ...

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    19. Assessment of post-dilatation strategies for optimal stent expansion in calcified coronary lesions: Ex vivo analysis with optical coherence tomography

      Assessment of post-dilatation strategies for optimal stent expansion in calcified coronary lesions: Ex vivo analysis with optical coherence tomography

      Introduction: Interventional cardiologists make adjustments in the presence of coronary calcifications known to limit stent expansion, but proper balloon sizing, plaque-modification approaches, and high-pressure regimens are not well established. Intravascular optical coherence tomography (IVOCT) provides high-resolution images of coronary tissues, including detailed imaging of calcifications, and accurate measurements of stent deployment, providing a means for detailed study of stent deployment. Objective: Evaluate stent expansion in an ex vivo model of calcified coronary arteries as a function of balloon size and high-pressure, post-dilatation strategies. Methods: We conducted experiments on cadaver hearts with calcified coronary lesions. We assessed stent expansion as a ...

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    20. Quantitative and qualitative characterization of retinal dystrophies in canine models of inherited retinal diseases using spectral domain optical coherence tomography (SD-OCT)

      Quantitative and qualitative characterization of retinal dystrophies in canine models of inherited retinal diseases using spectral domain optical coherence tomography (SD-OCT)

      The purpose of this study was to establish spectral domain optical coherence tomography (SD-OCT) assessment data in well-established canine models of inherited retinal dystrophies: PDE6B-rod-cone dysplasia 1 (RCD1: early onset retinitis pigmentosa), PRCD-progressive rod-cone degeneration (PRCD: late onset retinitis pigmentosa), CNGB3-achromatopsia, and RPE65-Leber congenital amaurosis (LCA). High resolution SD-OCT images of the retina were acquired from both eyes in 5 planes: temporal; superotemporal; superior; nasal; and inferior in adult dogs with: RCD1 (n = 4 dogs, median age: 1.5 yrs); PRCD (n = 2, 4.3 yrs); LCA (n = 3, 5.2 yrs); achromatopsia (n = 3, 4.2 yrs); and wild ...

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    21. Normative data and associations of Optical Coherence Tomography Angiography measurements of the macula: The Singapore Malay Eye Study

      Normative data and associations of Optical Coherence Tomography Angiography measurements of the macula: The Singapore Malay Eye Study

      Objective: To describe the normative quantitative parameters of macular retinal vasculature and their systemic and ocular associations, using optical coherence tomography angiography (OCTA). Design: Population based cross sectional study SUBJECTS: Adults above 50 years old were recruited from the third examination of the population-based Singapore Malay Eye Study. Methods: All participants underwent standardized comprehensive examination and Spectral domain-OCTA (Optovue, USA) of the macula. OCTA scans with pre-existing retinal disease, macular pathology, and poor quality were excluded. Main outcome measures: Normative quantitative vessel densities of the superficial, deep layer and foveal avascular zone were evaluated. Ocular and systemic associations with macular ...

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    22. Changes of blood flow in macular zone of patients with diabetic retinopathy at different stages evaluated by optical coherence tomography angiography

      Changes of blood flow in macular zone of patients with diabetic retinopathy at different stages evaluated by optical coherence tomography angiography

      Purpose: To evaluate changes in macular blood flow in patients with various stages of diabetic retinopathy (DR) by optical coherence tomography angiography (OCTA). Materials and methods: The data of 94 patients (122 eyes) with type 2 diabetes mellitus admitted from January 2018 to May 2021 were recorded, including 31 patients (42 eyes) with no DR (NDR group), 33 patients (40 eyes) with mild non-proliferative DR (mild NPDR group) and 30 patients (40 eyes) with moderate NPDR (moderate NPDR group). Forty healthy patients (40 eyes) who were examined during the same period were selected as control group. The blood flow densities ...

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    23. A novel algorithm for multiplicative speckle noise reduction in ex vivo human brain OCT images

      A novel algorithm for multiplicative speckle noise reduction in ex vivo human brain OCT images

      Optical coherence tomography (OCT) images of ex vivo human brain tissue are corrupted by multiplicative speckle noise that degrades the contrast to noise ratio (CNR) of microstructural compartments. This work proposes a novel algorithm to reduce noise corruption in OCT images that minimizes the penalized negative log likelihood of gamma distributed speckle noise. The proposed method is formulated as a majorize-minimize problem that reduces to solving an iterative regularized least squares optimization. We demonstrate the usefulness of the proposed method by removing speckle in simulated data, phantom data and real OCT images of human brain tissue. We compare the proposed ...

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    24. Retinal changes in bipolar disorder as an endophenotype candidate: Comparison of OCT-detected retinal changes in patients, siblings, and healthy controls

      Retinal changes in bipolar disorder as an endophenotype candidate: Comparison of OCT-detected retinal changes in patients, siblings, and healthy controls

      Optical coherence tomography (OCT) is a non-invasive imaging technique that detects retinal changes reflecting neurodegeneration. In recent studies in patients with bipolar disorder (BD) abnormal OCT findings have shown. In this study, we aimed to investigate the retinal changes in BD patients and their healthy siblings (HS) by comparing them with the healthy control (HC) group and to explore these findings as potential endophenotype candidates. 31 patients with BD, 31 age-matched HSs and 46 HCs were included and peripapillary retinal nerve fiber layer (RNFL), ganglion cell layer (GCL)+inner plexiform layer (IPL) and macular volume (MV) thicknesses were measured by ...

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