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    1. Comparison between Widefield Optical Coherence Tomography Devices in Eyes with High Myopia

      Comparison between Widefield Optical Coherence Tomography Devices in Eyes with High Myopia

      Background: To compare four different optical coherence tomography (OCT) devices for visualization of retinal and subretinal layers in highly myopic eyes. Methods: In this prospective, observational, cross-sectional study, consecutive patients with high myopia and control subjects were imaged by four OCT devices: Spectralis OCT2, PlexElite 2.0 100 kHz, PlexElite 2.0 200 kHz and the Canon Xephilio OCT-S1. The acquisition protocol for comparison consisted of single vertical and horizontal line scans centered on the fovea. Comparison between the devices in the extent of visible retina, presence of conjugate image or mirror artifacts, visibility of the sclerochoroidal interface and retrobulbar ...

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      Mentions: UCLA
    2. Retinal Vascularization Analysis on Optical Coherence Tomography Angiography before and after Intraretinal or Subretinal Fluid Resorption in Exudative Age-Related Macular Degeneration: A Pilot Study

      Retinal Vascularization Analysis on Optical Coherence Tomography Angiography before and after Intraretinal or Subretinal Fluid Resorption in Exudative Age-Related Macular Degeneration: A Pilot Study

      The aim was to analyze the variations in macular vascularization on optical coherence tomography angiography (OCTA) according to the presence of intraretinal fluid (IRF) induced by exudative age-related macular degeneration (AMD). We included exudative AMD patients with IRF and/or subretinal fluid (SRF) and age-matched control eyes. All patients underwent a macular 6 × 6 mm swept-source OCTA. The mean perfusion density (MPD) and mean vascular density (MVD) were calculated in the superficial (SCP) and the deep (DCP) capillary plexus at two timepoints: during an episode of exudation (T0) and after its total resorption (T1). A total of 22 eyes in ...

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    3. Photonics, Vol. 8, Pages 118: Digital Image Processing and Development of Machine Learning Models for the Discrimination of Corneal Pathology: An Experimental Model

      Photonics, Vol. 8, Pages 118: Digital Image Processing and Development of Machine Learning Models for the Discrimination of Corneal Pathology: An Experimental Model

      Machine learning (ML) has an impressive capacity to learn and analyze a large volume of data. This study aimed to train different algorithms to discriminate between healthy and pathologic corneal images by evaluating digitally processed spectral-domain optical coherence tomography (SD-OCT) corneal images. A set of 22 SD-OCT images belonging to a random set of corneal pathologies was compared to 71 healthy corneas (control group). A binary classification method was applied where three approaches of ML were explored. Once all images were analyzed, representative areas from every digital image were also extracted, processed and analyzed for a statistical feature comparison between ...

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    4. Generation of Augmented Capillary Network Optical Coherence Tomography Image Data of Human Skin for Deep Learning and Capillary Segmentation

      Generation of Augmented Capillary Network Optical Coherence Tomography Image Data of Human Skin for Deep Learning and Capillary Segmentation

      The segmentation of capillaries in human skin in full-field optical coherence tomography (FF-OCT) images plays a vital role in clinical applications. Recent advances in deep learning techniques have demonstrated a state-of-the-art level of accuracy for the task of automatic medical image segmentation. However, a gigantic amount of annotated data is required for the successful training of deep learning models, which demands a great deal of effort and is costly. To overcome this fundamental problem, an automatic simulation algorithm to generate OCT-like skin image data with augmented capillary networks (ACNs) in a three-dimensional volume (which we called the ACN data) is ...

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    5. Longitudinal Changes on Optical Coherence Tomography Angiography in Retinal Vein Occlusion

      Longitudinal Changes on Optical Coherence Tomography Angiography in Retinal Vein Occlusion

      Background: To evaluate the longitudinal changes on optical coherence tomography angiography (OCTA) in retinal vein occlusion (RVO). Methods: Retrospective study of patients with RVO treated with intravitreal anti-vascular endothelial growth factors (VEGF) for macular edema. Foveal avascular zone (FAZ) area, vessel density (VD), vessel length density (VLD), and adjusted flow index (AFI) were calculated. The unaffected eye of each participant was used as a control. Results: Twelve RVO eyes were included, receiving 6 ± 3 anti-VEGF injections over a follow-up of 10.4 ± 3.1 months. Compared to fellow eyes, RVO eyes had lower VD and VLD at inclusion ( p = 0 ...

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    6. Optical Coherence Tomography of Plaque Erosion and Thrombus in Severe Vertebral Artery Stenosis

      Optical Coherence Tomography of Plaque Erosion and Thrombus in Severe Vertebral Artery Stenosis

      A 69-year-old male presented with medically refractory vertebrobasilar insufficiency and paroxysmal subjective dizziness for six months. Severe stenosis of a dominant left V2 vertebral artery segment was identified on digital subtraction angiography (DSA) with an irregular intraluminal filling defect immediately above the stenosis. Optical coherence tomography (OCT) demonstrated a normal lumen at the distal end, with red thrombus detected distal to the stenosis. Atherosclerotic plaque containing fibro-lipid was also identified and treated with a drug-eluting stent. Distal red thrombi were not covered by stenting, indicating embolization risk in the future. Clear posterior fossa symptoms occurred after intervention, and treatment with ...

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    7. Retinal Microvascular Impairment in COVID-19 Bilateral Pneumonia Assessed by Optical Coherence Tomography Angiography

      Retinal Microvascular Impairment in COVID-19 Bilateral Pneumonia Assessed by Optical Coherence Tomography Angiography

      The purpose of this study was to evaluate the presence of retinal and microvascular alterations in COVID-19 patients with bilateral pneumonia due to SARS-COV-2 that required hospital admission and compare this with a cohort of age- and sex-matched controls. COVID-19 bilateral pneumonia patients underwent retinal imaging 14 days after hospital discharge with structural optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) measurements. Vessel density (VD) and foveal avascular zone (FAZ) area were evaluated in the superficial, deep capillary plexus (SCP, DCP), and choriocapillaris (CC). After exclusion criteria, only one eye per patient was selected, and 50 eyes (25 ...

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    8. Characterization of Optical Coherence Tomography Images for Colon Lesion Differentiation under Deep Learning

      Characterization of Optical Coherence Tomography Images for Colon Lesion Differentiation under Deep Learning

      Background: Clinicians demand new tools for early diagnosis and improved detection of colon lesions that are vital for patient prognosis. Optical coherence tomography (OCT) allows microscopical inspection of tissue and might serve as an optical biopsy method that could lead to in-situ diagnosis and treatment decisions; (2) Methods: A database of murine (rat) healthy, hyperplastic and neoplastic colonic samples with more than 94,000 images was acquired. A methodology that includes a data augmentation processing strategy and a deep learning model for automatic classification (benign vs. malignant) of OCT images is presented and validated over this dataset. Comparative evaluation is ...

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    9. Retinal and Choriocapillaris Vascular Changes in Patients Affected by Different Clinical Phenotypes of β-Thalassemia: An Optical Coherence Tomography Angiography Study

      Retinal and Choriocapillaris Vascular Changes in Patients Affected by Different Clinical Phenotypes of β-Thalassemia: An Optical Coherence Tomography Angiography Study

      In this cross-sectional study we assessed the vascular alterations in retinal and choriocapillaris perfusion in patients affected by β-thalassemia, by means of optical coherence tomography angiography (OCTA). A total of 124 eyes of 62 patients (mean age 44.74 ± 5.79 years old) affected by β-thalassemia (transfusion dependent thalassemia (TDT), non-transfusion dependent thalassemia (NTDT) and minor) were compared to 40 eyes of twenty healthy subjects. We evaluated the vessel density (VD) in superficial capillary plexus, deep capillary plexus, radial peripapillary capillary, choriocapillaris and the foveal avascular zone area. The TDT group showed a statistically significant reduction in retinal and choriocapillaris ...

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    10. Functional Monitoring after Trabeculectomy or XEN Microstent Implantation Using Spectral Domain Optical Coherence Tomography and Visual Field Indices—A Retrospective Comparative Cohort Study

      Functional Monitoring after Trabeculectomy or XEN Microstent Implantation Using Spectral Domain Optical Coherence Tomography and Visual Field Indices—A Retrospective Comparative Cohort Study

      The aim of this study was to compare the efficacy of trabeculectomy (TE), single XEN microstent implantation (solo XEN) or combined XEN implantation and cataract surgery (combined XEN) in primary open-angle glaucoma cases, naïve to prior surgical treatment, using a monocentric retrospective comparative cohort study. Intraocular pressure (IOP) and the number of IOP-lowering drugs (Meds) were monitored during the first 24 months after surgery. Further disease progression was monitored using peripapillary retinal nerve fiber layer (RNFL) thickness examinations using spectral domain optical coherence tomography (OCT) as well as visual acuity (VA) and visual field (VF) tests. In the TE ...

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    11. The Paediatric Glaucoma Diagnostic Ability of Optical Coherence Tomography: A Comparison of Macular Segmentation and Peripapillary Retinal Nerve Fibre Layer Thickness

      The Paediatric Glaucoma Diagnostic Ability of Optical Coherence Tomography: A Comparison of Macular Segmentation and Peripapillary Retinal Nerve Fibre Layer Thickness

      Cite This Paper Simple Summary Optical coherence tomography (OCT) is an established ophthalmologic diagnostic tool to visualise vital retinal structures. In glaucoma, it is used to quantify the thickness decrease in the peripapillary retinal nerve fibre layer (pRNFL) and in the macula. While glaucoma management in adults incorporates traditional clinical parameters as well as instrumental methods such as OCT, guidelines for paediatric glaucoma focus on conventional methods.

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    12. Use of Vibrational Optical Coherence Tomography to Analyze the Mechanical Properties of Composite Materials

      Use of Vibrational Optical Coherence Tomography to Analyze the Mechanical Properties of Composite Materials

      Energy storage and dissipation by composite materials are important design parameters for sensors and other devices. While polymeric materials can reversibly store energy by decreased chain randomness (entropic loss) they fail to be able to dissipate energy effectively and ultimately fail due to fatigue and molecular chain breakage. In contrast, composite tissues, such as muscle and tendon complexes, store and dissipate energy through entropic changes in collagen (energy storage) and viscous losses (energy dissipation) by muscle fibers or through fluid flow of the interfibrillar matrix. In this paper we review the molecular basis for energy storage and dissipation by natural ...

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    13. Optical Coherence Tomography Angiography Monitors Cutaneous Wound Healing under Angiogenesis-Promoting Treatment in Diabetic and Non-Diabetic Mice

      Optical Coherence Tomography Angiography Monitors Cutaneous Wound Healing under Angiogenesis-Promoting Treatment in Diabetic and Non-Diabetic Mice

      During wound healing, the rapid re-establishment of a functional microcirculation in the wounded tissue is of utmost importance. We applied optical coherence tomography (OCT) angiography to evaluate vascular remodeling in an excisional wound model in the pinnae of C57BL/6 and db/db mice receiving different proangiogenic topical treatments. Analysis of the high-resolution OCT angiograms, including the four quantitative parameters vessel density, vessel length, number of bifurcations, and vessel tortuosity, revealed changes of the microvasculature and allowed identification of the overlapping wound healing phases hemostasis, inflammation, proliferation, and remodeling. Angiograms acquired in the inflammatory phase in the first days showed ...

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    14. OCT Capillary Depth Measurement in Copper Micro Welding Using Green Lasers

      OCT Capillary Depth Measurement in Copper Micro Welding Using Green Lasers

      The transition of the powertrain from combustion to electric systems increases the demand for reliable copper connections. For such applications, laser welding has become a key technology. Due to the complexity of laser welding, especially at micro welding with small weld seam dimensions and short process times, reliable in-line process monitoring has proven to be difficult. By using a green laser with a wavelength of λ = 515 nm, the welding process of copper benefits from an increased absorption, resulting in a shallow and stable deep penetration welding process. This opens up new possibilities for the process monitoring. In this contribution, the ...

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    15. Globotrioasylsphingosine Levels and Optical Coherence Tomography Angiography in Fabry Disease Patients

      Globotrioasylsphingosine Levels and Optical Coherence Tomography Angiography in Fabry Disease Patients

      Background: To date, there are no studies associating the dried blood spot (DBS) levels of globotrioasylsphingosine (lysoGb3) with quantitative optical coherence tomography angiography (OCTA) parameters in Fabry disease (FD) patients. Here, we aimed to investigate the association between OCTA vessel density (VD), vessel length density (VLD) with DBS lysoGb3. Methods: A retrospective, single center analysis of all consecutive FD patients enrolled at the Department of Ophthalmology of the University Hospital of Zurich from 1 December 2017 to 9 September 2020. An association between VD and VLD detected by OCTA and lysoGb3 was investigated using a linear mixed model. Results: A ...

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    16. Quantitative Optical Coherence Tomography Angiography (OCTA) Parameters in a Black Diabetic Population and Correlations with Systemic Diseases

      Quantitative Optical Coherence Tomography Angiography (OCTA) Parameters in a Black Diabetic Population and Correlations with Systemic Diseases

      This is a cross-sectional, prospective study of a population of black diabetic participants without diabetic retinopathy aimed to investigate optical coherence tomography angiography (OCTA) characteristics and correlations with systemic diseases in this population. These parameters could serve as novel biomarkers for microvascular complications; especially in black populations which are more vulnerable to diabetic microvascular complications. Linear mixed models were used to obtain OCTA mean values ± standard deviation and analyze statistical correlations to systemic diseases. Variables showing significance on univariate mixed model analysis were further analyzed with multivariate mixed models. 92 eyes of 52 black adult subjects were included. After multivariate ...

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    17. The Role of Optical Coherence Tomography Angiography(OCTA) in Detecting Choroidal Neovascularization in DifferentStages of Best Macular Dystrophy: A Case Series

      The Role of Optical Coherence Tomography Angiography(OCTA) in Detecting Choroidal Neovascularization in DifferentStages of Best Macular Dystrophy: A Case Series

      Best macular dystrophy (BMD) is an autosomal dominant macular dystrophy of childhood onset characterized by bilateral and symmetric vitelliform lesions. Several stages of disease have been well-described in the literature. Choroidal neovascularization (CNV) has traditionally been considered a hallmark of end-stage disease, and anti-vascular endothelial growth factor (anti-VEGF) agents have been used to improve visual prognosis. While CNV was historically detected with fluorescein angiography, optical coherence tomography angiography (OCTA) has recently been employed as a novel mechanism for identifying CNV in BMD. In this case series, we discuss our institutional experience with using OCTA to detect CNV in BMD and ...

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    18. Swept Source Optical Coherence Tomography Analysis of the Selected Eye’s Anterior Segment Parameters

      Swept Source Optical Coherence Tomography Analysis of the Selected Eye’s Anterior Segment Parameters

      Background: The present study determined the mean reference values of the anterior segment parameters of the selected eye using swept source optical coherence tomography (SS-OCT) in healthy Caucasian participants. Methods: A total of 166 volunteers (age 54–79 years), women ( n = 92) and men ( n = 74), were analyzed. One eye of each subject was randomly selected for anterior segment imaging. The anterior segment of the eye was scanned with CASIA2. The analyzed anterior segment parameters were divided into three groups, namely parameters of the cornea, lens, and angle. Results: The OCT (e.g., Ks, Kf, pKf, pKs, and central corneal ...

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    19. Dynamics of Central Remyelination and Treatment Evolution in a Model of Multiple Sclerosis with Optic Coherence Tomography

      Dynamics of Central Remyelination and Treatment Evolution in a Model of Multiple Sclerosis with Optic Coherence Tomography

      The need for remyelinating drugs is essential for healing disabling diseases such as multiple sclerosis (MS). One of the reasons for the lack of this class of therapies is the impossibility to monitor remyelination in vivo, which is of utmost importance to perform effective clinical trials. Here, we show how optical coherence tomography (OCT), a cheap and non-invasive technique commonly used in ophthalmology, may be used to assess remyelination in vivo in MS patients. Our pioneer approach validates OCT as a technique to study remyelination of the optic nerve and reflects what is occurring in non-accessible central nervous system (CNS ...

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    20. Postmortem Ocular Findings in the Optical Coherence Tomography Era: A Proof of Concept Study Based on Six Forensic Cases

      Postmortem Ocular Findings in the Optical Coherence Tomography Era: A Proof of Concept Study Based on Six Forensic Cases

      Postmortem analysis of the ocular globe is an important topic for forensic pathology and transplantology. Although crucial elements may be gathered from examining cadaveric eyes, the latter do not routinely undergo in-depth analysis. The paucity of quantitative and objective data that are obtainable using current, invasive necroscopic techniques is the main reason for the limited interest in this highly specialized procedure. The aim of the current study is to describe and to object for the first time the postmortem ocular changes by mean of portable optical coherence tomography for evaluating ocular tissues postmortem. The design involved the postmortem analysis (in ...

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    21. Optical Coherence Tomography Angiography of the Choriocapillaris in Age-Related Macular Degeneration

      Optical Coherence Tomography Angiography of the Choriocapillaris in Age-Related Macular Degeneration

      The advent of optical coherence tomography angiography (OCTA) has allowed for remarkable advancements in our understanding of the role of the choriocapillaris in age-related macular degeneration (AMD). As a relatively new imaging modality, techniques to analyze and quantify choriocapillaris images are still evolving. Quantification of the choriocapillaris requires careful consideration of many factors, including the type of OCTA device, segmentation of the choriocapillaris slab, image processing techniques, and thresholding method. OCTA imaging shows that the choriocapillaris is impaired in intermediate non-neovascular AMD, and the severity of impairment may predict the advancement of disease. In advanced atrophic AMD, the choriocapillaris is ...

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    22. Neovascularization in Human Intracranial Atherosclerotic In-Stent Restenosis

      Neovascularization in Human Intracranial Atherosclerotic In-Stent Restenosis

      Optical coherence tomography (OCT) has seen widespread use in cardiovascular and interventional endovascular imaging. While scattered reports of intracranial usage have been reported for the assessment of atherosclerotic stenosis, nutrifying neovasculature supplying plaque and neointima have not been demonstrated until now. We report the first in-vivo illustration of this phenomenon, which is a high-resolution depiction of a critical pathway for in-stent restenosis.

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    23. Integrated Quad-Scanner Strategy-Based Optical Coherence Tomography for the Whole-Directional Volumetric Imaging of a Sample

      Integrated Quad-Scanner Strategy-Based Optical Coherence Tomography for the Whole-Directional Volumetric Imaging of a Sample

      Whole-directional scanning methodology is required to observe distinctive features of an entire physical structure with a three dimensional (3D) visualization. However, the implementation of whole-directional scanning is challenging for conventional optical coherence tomography (OCT), which scans a limited portion of the sample by utilizing unidirectional and bidirectional scanning methods. Therefore, in this paper an integrated quad-scanner (QS) strategy-based OCT method was implemented to obtain the whole-directional volumetry of a sample by employing four scanning arms installed around the sample. The simultaneous and sequential image acquisition capabilities are the conceptual key points of the proposed QS-OCT method, and were implemented using ...

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    24. Clinical Utility of Artificial Intelligence Algorithms to Enhance Wide-Field Optical Coherence Tomography Angiography Images

      Clinical Utility of Artificial Intelligence Algorithms to Enhance Wide-Field Optical Coherence Tomography Angiography Images

      The aim of this paper is to investigate the clinical utility of the application of deep learning denoise algorithms on standard wide-field Optical Coherence Tomography Angiography (OCT-A) images. This was a retrospective case-series assessing forty-nine 10 × 10 mm OCT-A1 macula scans of 49 consecutive patients attending a medical retina clinic over a 6-month period. Thirty-seven patients had pathology; 13 had none. Retinal vascular layers were categorised into superficial or deep capillary plexus. For each category, the retinal experts compared the original standard image with the same image that had intelligent denoise applied. When analysing the Superficial Capillary Plexus (SCP), the ...

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