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    1. Unique corneal tomography features of allergic eye disease identified by OCT imaging and artificial intelligence

      Unique corneal tomography features of allergic eye disease identified by OCT imaging and artificial intelligence

      The purpose of this study was to assess unique corneal tomographic parameters of allergic eye disease (AED) using optical coherence tomography (OCT) and artificial intelligence (AI). A total of 57 eyes diagnosed with AED were included. The curvature and aberrations of the air‐epithelium (A‐E) and epithelium‐Bowman's layer (E‐B) interfaces were calculated. Random forest AI models were built combing this data with the parameters of healthy, forme fruste keratoconus (FFKC) and KC eyes. The AI models were cross‐validated with 3‐fold random sampling. Each model was limited to 10 trees. The AI model incorporating both ...

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    2. Determination of retinal nerve fibre layer (RNFL ) and ganglion cell/inner plexiform layers progression rates using two optical coherence tomography systems – the PROGRESSA study

      Determination of retinal nerve fibre layer (RNFL ) and ganglion cell/inner plexiform layers progression rates using two optical coherence tomography systems – the PROGRESSA study

      Importance Glaucoma progression rates may differ depending on the retinal structural parameters measured and between devices. Background To compare retinal nerve fibre layer (RNFL) and ganglion cell/inner plexiform layers (GCL/IPL) progression rates using two spectral‐domain optical coherence tomography (OCT) systems. Design Prospective, university hospital setting. Participants Cross‐sectional study: 100 eyes from 53 glaucoma suspects and early manifest glaucoma cases. Longitudinal study: subset of 61 eyes from 33 participants. Methods Same day optic nerve and macular images were acquired using Cirrus and Spectralis systems from which RNFL and GCL/IPL thicknesses were calculated. Longitudinal analysis of RNFL ...

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    3. Optical Coherence Tomography Angiography for Mapping Cerebral Microvasculature Based on Normalized Differentiation Analysis

      Optical Coherence Tomography Angiography for Mapping Cerebral Microvasculature Based on Normalized Differentiation Analysis

      Optical coherence tomography angiography (OCTA) is a label‐free, noninvasive biomedical imaging modality for mapping microvascular networks and quantifying blood flow velocities in vivo . Simple computation and fast processing are critical for the OCTA in some applications. Herein, we report on a normalized differentiation method for mapping cerebral microvasculature with the advantages of simple analysis and high image quality, benefitting from computation of differentiation and characteristics of normalization. Normalized differentiation values are validated to have a nearly linear relationship with flow velocities in a range using a flow phantom. The measurements in a rat cerebral cortex show that the OCTA ...

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    4. Determination and correction of aberrations in full field OCT using phase gradient autofocus by maximizing the likelihood function

      Determination and correction of aberrations in full field OCT using phase gradient autofocus by maximizing the likelihood function

      A method for numerical estimation and correction of aberrations of the eye in fundus imaging with optical coherence tomography (OCT) is presented. Aberrations are determined statistically by using the estimate based on likelihood function maximization. The method can be considered as an extension of the phase gradient autofocusing algorithm in synthetic aperture radar imaging to 2D optical aberration correction. The efficacy of the proposed method has been demonstrated in OCT fundus imaging with 6λ aberrations. After correction, single photoreceptors were resolved. It is also shown that wavefront distortions with high spatial frequencies can be determined and corrected.

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    5. Three‐year outcome with drug‐coated balloon percutaneous coronary intervention in coronary Takayasu arteritis: A case review

      Three‐year outcome with drug‐coated balloon percutaneous coronary intervention in coronary Takayasu arteritis: A case review

      We describe the first long‐term follow‐up of a young patient with active Takayasu arteritis who presented with an acute coronary syndrome, treated endovascularly with percutaneous coronary intervention without stenting. A drug‐coated balloon was used with high‐resolution coronary imaging guidance in the form of optical coherence tomography on a critical ostial left anterior descending coronary artery lesion. A repeat procedure was undertaken after 4 months confirming a durable coronary angioplasty result and the patient remained symptom‐free beyond 3 years. Coronary stenting in this population is associated with early and aggressive stent failure. Hence, this is an ...

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    6. Diagnosis of chronic stage of hypertensive retinopathy based on spectral domain optical coherence tomography

      Diagnosis of chronic stage of hypertensive retinopathy based on spectral domain optical coherence tomography

      Hypertensive retinopathy refers to the retinal vascular changes associated with systemic arterial hypertension. Hypertensive retinopathy can be divided into chronic and acute phases. A cross‐sectional study was performed to explore a method of measurement in the diameters of retinal vessels for diagnosis of chronic hypertensive retinopathy based on spectral domain optical coherence tomography (SD‐OCT). The central retinal artery diameter (CRAD), the central retinal vein diameter (CRVD), and the artery‐to‐vein ratio (AVR) were measured. A total of 119 subjects with 119 eyes were included in this study, in which 56 subjects with 56 eyes were included in ...

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    7. Towards quantitative assessment of burn based on photoacoustic and optical coherence tomography

      Towards quantitative assessment of burn based on photoacoustic and optical coherence tomography

      Accurate and timely assessment of the severity of burn is essential for the treatment of burns. Currently, although most first‐degree and third‐degree burns are easily diagnosed through visual inspection or auxiliary diagnostic methods, the second‐degree burn is still difficult to distinguish due to the ambiguity boundaries of second‐degree with first‐degree and third‐degree burns. In this study, we proposed a non‐invasive technique by combing photoacoustic imaging (PAI) and optical coherence tomography (OCT) to multi‐parameter quantitatively assess the burns. The feasibility and capacity of the dual‐mode PAT/OCT for assessing the burns was ...

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    8. Detailed optical coherence tomography angiographic short‐term response of type 3 neovascularization to combined treatment with photodynamic therapy and intravitreal bevacizumab

      Detailed optical coherence tomography angiographic short‐term response of type 3 neovascularization to combined treatment with photodynamic therapy and intravitreal bevacizumab

      Purpose To explore the short‐term vascular and structural changes of type 3 neovascularization using optical coherence tomography angiography (OCT‐A) when treated with a combination of photodynamic therapy (PDT) and intravitreal bevacizumab (IVB), and to evaluate the course of different sequences of the combined therapies. Methods Thirty eyes of 29 treatment‐naïve patients with a type 3 neovascularization were included in this prospective observational cohort study. They were all treated with PDT and IVB 2 weeks apart, starting either with PDT (PDT‐first group) or IVB (IVB‐first group). Optical coherence tomography angiography (OCT‐A) imaging was performed ...

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    9. Prevalence, risk factors and impact of posterior staphyloma diagnosed from wide‐field optical coherence tomography in Singapore adults with high myopia

      Prevalence, risk factors and impact of posterior staphyloma diagnosed from wide‐field optical coherence tomography in Singapore adults with high myopia

      Purpose To investigate the prevalence and risk factors of posterior staphyloma using wide‐field optical coherence tomography (WF‐OCT) in adults with high myopia in Singapore. Design Population‐based cross‐sectional study. Methods Adults with spherical equivalent (SE) ≤ −5D in either eye at the first visit of Singapore Epidemiology of Eye Diseases study and Singapore Prospective Study Program study were recruited. Posterior staphyloma was diagnosed using WF‐OCT (PLEX ® Elite9000, Carl Zeiss Meditec). Myopic macular degeneration (MMD), myopic traction maculopathy (MTM) and vision‐related quality of life (VRQoL) were assessed using fundus photographs, DRI‐Triton OCT (Topcon) and the Impact ...

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    10. Optical coherence tomography measures correlate with brain and spinal cord atrophy and multiple sclerosis disease‐related disability

      Optical coherence tomography measures correlate with brain and spinal cord atrophy and multiple sclerosis disease‐related disability

      ackground Both, optical coherence tomography (OCT) and MRI volumetric measures have been postulated as potential biomarkers of MS related disability. Objective To investigate the association between OCT and brain volume (BV) and spinal cord area (SCA) parameters in relapsing MS patients, and to assess their independent associations with disability. Methods Cross‐sectional analysis of 90 MS patients that underwent OCT and MRI exams. Values of peripapillary retinal nerve fibre layer (pRNFL), ganglion cell‐inner plexiform layer (GCIPL), and inner nuclear layer (INL) of eyes without previous ON were obtained. SCA and brain parenchymal, grey and white matter fractions (BPF, GMF ...

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    11. A comparison of choroidal thicknesses between pachychoroid and normochoroid eyes acquired from wide‐field swept‐source OCT

      A comparison of choroidal thicknesses between pachychoroid and normochoroid eyes acquired from wide‐field swept‐source OCT

      Purpose We investigated the wide‐field choroidal thickness (CT) using swept‐source optical coherence tomography (SS‐OCT) and compared the characteristics of the choroidal layer between pachychoroid and normochoroid groups. Methods A total of 120 eyes from 120 normal subjects were included. All subjects were divided into two groups according to the subfoveal CT (≥300 μm, pachychoroid group; <300μm, normochoroid group). All subjects underwent an HD spotlight 16 mm scan using SS‐OCT. The CT was measured at the following 12 points: subfoveal, 3 points in the nasal peripapillary area, 6 points in the macular area and 2 peripheral ...

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    12. Prediction of response to anti‐vascular endothelial growth factor treatment in diabetic macular oedema using an optical coherence tomography‐based machine learning method

      Prediction of response to anti‐vascular endothelial growth factor treatment in diabetic macular oedema using an optical coherence tomography‐based machine learning method

      Purpose To predict the anti‐vascular endothelial growth factor (VEGF) therapeutic response of diabetic macular oedema (DME) patients from optical coherence tomography (OCT) at the initiation stage of treatment using a machine learning‐based self‐explainable system. Methods A total of 712 DME patients were included and classified into poor and good responder groups according to central macular thickness decrease after three consecutive injections. Machine learning models were constructed to make predictions based on related features extracted automatically using deep learning algorithms from OCT scans at baseline. Five‐fold cross‐validation was applied to optimize and evaluate the models. The ...

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    13. Optical coherence tomography imaging of excised canine apocrine gland anal sac adenocarcinoma tumors

      Optical coherence tomography imaging of excised canine apocrine gland anal sac adenocarcinoma tumors

      Optical coherence tomography (OCT) is an optical imaging modality that has been investigated for real‐time surgical margin evaluation in human breast cancer patients. Previous veterinary OCT studies have been limited to surgical margin imaging for soft tissue sarcoma (STS) tumors. To the authors knowledge, OCT has never been used to characterize or evaluate other types of neoplasia in dogs. The goal of this study was to characterize the OCT imaging appearance of apocrine gland anal sac adenocarcinoma (AGASACA) in excised ex vivo specimens from five client‐owned dogs. All excised tissue surgical margins were imaged using a clinical spectral ...

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    14. Evaluating optical coherence tomography for surgical margin assessment of canine mammary tumors

      Evaluating optical coherence tomography for surgical margin assessment of canine mammary tumors

      Optical coherence tomography (OCT) uses near‐infrared light waves to generate real‐time, high‐resolution images on the microscopic scale similar to low power histopathology. Previous studies have demonstrated the use of OCT for real‐time surgical margin assessment for human breast cancer. The use of OCT for canine mammary tumors (CMT) could allow intra‐operative visualization of residual tumor at surgical margins. The purpose of this study was to assess OCT imaging for the detection of incomplete tumor resection following CMT surgery. We hypothesized that OCT images would have comparable features to histopathological images of tissues at the surgical ...

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    15. Quantitative Assessment of Optical Coherence Tomography Angiography Algorithms for Neuroimaging

      Quantitative Assessment of Optical Coherence Tomography Angiography Algorithms for Neuroimaging

      Optical coherence tomography (OCT) angiography can noninvasively map microvascular networks and quantify blood flow in a cerebral cortex with a resolution of 1–10 μm and a penetration depth of 2–3 mm incorporating OCT signals and angiography algorithms. Different angiography algorithms have been developed in recent years; however, the performance of the algorithms has not been assessed quantitatively for neuroimaging applications. In this paper, we developed four metrics including vascular connectivity, contrast‐to‐noise ratio (CNR), signal‐to‐noise ratio (SNR) and processing time to quantitatively assess the performance of OCT angiography algorithms in image quality and computation speed ...

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      Mentions: Jiang Zhu
    16. Dynamic Optical Coherence Tomography Imaging of Telangiectasia Prior to Intense Pulsed Light Treatment—An Opportunity to Target Treatment?

      Dynamic Optical Coherence Tomography Imaging of Telangiectasia Prior to Intense Pulsed Light Treatment—An Opportunity to Target Treatment?

      Background and Objectives To investigate whether optical coherence tomography (OCT) could be utilized to characterize blood flow and vessel dimensions of facial telangiectasias before and during consecutive intense pulsed light (IPL) treatment. Study Design/Materials and methods Dynamic OCT (D‐OCT) was used to image telangiectasia immediately before and after, 1–3 days after, and 1 month after IPL treatment. Measurements included vessel width and depth, blood flow, and attenuation. Vessel dimensions at baseline were verified by a blinded observer. Clinical improvement was detected as good, moderate, or none, and adverse effects were registered at 1‐month follow‐up. Results ...

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    17. Quantification of diabetic macular ischemia using novel three‐dimensional optical coherence tomography angiography metrics

      Quantification of diabetic macular ischemia using novel three‐dimensional optical coherence tomography angiography metrics

      We applied three‐dimensional (3D) analysis to optical coherence tomography angiography (OCTA) to measure macular ischemia in eyes affected by non‐proliferative diabetic retinopathy (DR). A previously validated algorithm was applied to OCTA data in order to obtain 3D visualization of the retinal vasculature. Successively, a global thresholding algorithm was applied and two novel quantitative metrics were introduced: 3D vascular volume and 3D perfusion density. Two‐dimensional (2D) OCTA metrics were also obtained with different binarization thresholds for comparison. Of the 30 patients included, 15 were diagnosed with DR and 15 were controls. The 3D vascular volume and 3D perfusion ...

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    18. Retinal optical coherence tomography for children with cerebral palsy

      Retinal optical coherence tomography for children with cerebral palsy

      Many individuals with cerebral palsy (CP) also have damage to their central visual pathways. These comprise the right and left optic tract (from optic chiasm to lateral geniculate nucleus [LGN]); the optic radiations from LGN to the occipital cortex; and several other networks that integrate the visual information with motor, attentional, and cognitive centres. Topographic information about which part of the retina (hence where in the visual field) is stimulated by light is preserved throughout the optic nerve and the central visual pathways. Jacobson et al. describe how regional variations in retinal layer thickness can therefore reflect focal central visual ...

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    19. Cross‐scanning optical coherence tomography angiography for eye motion correction

      Cross‐scanning optical coherence tomography angiography for eye motion correction

      We propose a cross‐scanning optical coherence tomography (CS‐OCT) system to correct eye motion artifacts in OCT angiography images. This system employs a dual illumination configuration with two orthogonally polarized beams, each of which simultaneously perform raster scanning in perpendicular direction with each other over the same area. In the reference arm, a polarization delay unit is used to acquire the two orthogonally polarized interferograms with a single photodetector by introducing different optical delay lines. The two cross‐scanned volume data are affected by the same eye motion but in two orthogonal directions. We developed a motion correction algorithm ...

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      Mentions: Korea University
    20. Visibility of microvessels in Optical Coherence Tomography Angiography depends on angular orientation

      Visibility of microvessels in Optical Coherence Tomography Angiography depends on angular orientation

      OCT Angiography (OCTA) is a widespread tool for depth‐resolved imaging of chorioretinal vasculature with single microvessel resolution. To improve the clinical interpretation of OCTA, the conditions affecting visualization of microvessels must be defined. Here we inject a scattering plasma tracer (Intralipid) during OCTA imaging of the anesthetized rat eye. In the retina, we find that interlaminar (vertical) vessels that connect laminae have one‐fourth to one‐third the OCTA red blood cell to tracer (RBC‐to‐tracer) signal ratio of intralaminar (horizontal) vessels. This finding suggests that the OCTA signal from microvessels depends on angular orientation, making vertically‐oriented ...

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    21. Comparison of different morphologies of choroidal neovascularization evaluated by optical coherence tomography angiography in age‐related macular degeneration

      Comparison of different morphologies of choroidal neovascularization evaluated by optical coherence tomography angiography in age‐related macular degeneration

      Importance The clinical implications of different morphologies of choroidal neovascularization (CNV), as evaluated by optical coherence tomography angiography (OCTA) in neovascular age‐related macular degeneration (nAMD), are lacking. Background To describe the morphology of CNV in nAMD using OCTA, and to compare the visual prognosis and other structural OCT biomarkers between different morphologic patterns. Design Retrospective cohort study. Participants 140 eyes with nAMD treated with anti‐vascular endothelial growth factor (VEGF). Methods Patients were examined using OCTA prior to and at 3, 6, and 12 months after receiving anti‐VEGF therapy. Main Outcome Measures Best‐corrected visual acuity (BCVA) and ...

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    22. Optical coherence tomography neurodegenerative findings in patients with bipolar disorder

      Optical coherence tomography neurodegenerative findings in patients with bipolar disorder

      Introduction Neuroimaging studies of patients with bipolar disorder (BD) have recently revealed neurodegenerative changes in the central nervous system. Optical coherence tomography (OCT) imaging of the retina, as an extension of brain, may be a biomarker in understanding the neurobiology of the disease. To assess OCT as a tool to detect neurodegeneration in BD we compared the retinal changes between patients with BD and healthy individuals. Methods We performed complete ophthalmological examinations and took OCT images for 70 eyes of 70 patients with BD, and for age and sex‐matched individual controls. We compared retinal nerve fiber layers (RNFLs) and ...

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    23. In vivo Imaging of Sarcoptes scabiei infestation using Line‐field Confocal Optical Coherence Tomography

      In vivo Imaging of Sarcoptes scabiei infestation using Line‐field Confocal Optical Coherence Tomography

      Scabies remains a worldwide spread disease of considerable health and economic burden with repeated outbreaks in community settings.(1) Scabies agent is the ectoparasite Sarcoptes scabiei var. hominis ; this invisible mite causes a progressive rash, which can be misdiagnosed with eczema or pruritus sine materia . Diagnosis is based on characteristic clinical features (intense nightly itch, inflammatory excoriated papules in typical sites) and history of contact to infected patients.

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