1. 49-72 of 824 « 1 2 3 4 5 6 ... 33 34 35 »
    1. Correlation between morphological characteristics in spectral-domain-optical coherence tomography, different functional tests and a patient's subjective handicap in acute central serous chorioretinopathy

      Correlation between morphological characteristics in spectral-domain-optical coherence tomography, different functional tests and a patient's subjective handicap in acute central serous chorioretinopathy

      Purpose The purpose of this study was to identify quantitatively measurable morphologic optical coherence tomography (OCT) characteristics in patients with an acute episode of central serous chorioretinopathy (CSC) and evaluate their correlation to functional and psychological variables for their use in daily clinical practice. Methods Retinal thickness (RT), the height, area and volume of subretinal fluid (SRF)/pigment epithelium detachments were evaluated using the standardized procedures of the Vienna Reading Center. These morphologic characteristics were compared with functional variables [best-corrected visual acuity (BCVA), contrast sensitivity (CS), retinal sensitivity/microperimetry, fixation stability], and patients’ subjective handicap from CSC using the National ...

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    2. Observation of curative effect of intravitreal injection of conbercept in wet age-related macular degeneration: Optical coherence tomography analysis after injection

      Observation of curative effect of intravitreal injection of conbercept in wet age-related macular degeneration: Optical coherence tomography analysis after injection

      To observe the clinical efficacy of intravitreal injection of conbercept in the treatment of wet age-related macular degeneration (wAMD), optical coherence tomography (OCT) and the best corrected visual acuity (BCVA) was observed to measure the changes of anatomical changes of central macular thickness (CMT) and the area and volume of retinal pigment epithelium (RPE) uplift. Fifteen patients (15 eyes) with wet AMD were enrolled in this study. All patients underwent intravitreal injection of conbercept of 0.05 mL once. After 1 week, 1 month, and 3 months, OCT and BCVA were used to examine and to compare with the preoperative ...

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    3. Scaffold thrombosis following implantation of the Absorb Bvs in routine clinical practice: Insight into possible mechanisms from optical coherence tomography

      Scaffold thrombosis following implantation of the Absorb Bvs in routine clinical practice: Insight into possible mechanisms from optical coherence tomography

      Objectives To identify potential underlying mechanisms of early and (very) late scaffold thrombosis (ScT) by optical coherence tomography (OCT), in a frame-by-frame analysis. Background The absorb scaffold is associated with an increased risk of ScT compared with metallic stents. Several potential causes of bioresorbable ScT have been identified, however the precise etiology still remains unclear. Methods Between February 2013 and February 2016, 13 patients presenting with definite ScT underwent OCT imaging. After guidewire passage or balloon inflations, OCT images were acquired. Pullbacks were assessed offline at each 1 mm longitudinal interval within the treated segment and the 5 mm segments ...

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    4. Evaluating the Effects of Maternal Alcohol Consumption on Murine Fetal Brain Vasculature Using Optical Coherence Tomography

      Evaluating the Effects of Maternal Alcohol Consumption on Murine Fetal Brain Vasculature Using Optical Coherence Tomography

      Prenatal alcohol exposure (PAE) can result in a range of anomalies including brain and behavioral dysfunctions, collectively termed fetal alcohol spectrum disorder (FASD). PAE during the 1 st and 2 nd trimester is common, and research in animal models has documented significant neural developmental deficits associated with PAE during this period. However, little is known about the immediate effects of PAE on fetal brain vasculature. In this study, we used in utero speckle variance optical coherence tomography (SVOCT), a high spatial- and temporal–resolution imaging modality, to evaluate dynamic changes in micro-vasculature of the 2 nd trimester-equivalent murine fetal brain ...

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    5. Measuring polarization changes in the human outer retina with polarization-sensitive optical coherence tomography

      Measuring polarization changes in the human outer retina with polarization-sensitive optical coherence tomography

      Morphological changes in the outer retina such as drusen are established biomarkers to diagnose age-related macular degeneration. However earlier diagnosis might be possible by taking advantage of more subtle changes that accompany tissues that bear polarization-altering properties. To test this hypothesis, we developed a method based on polarization-sensitive optical coherence tomography with which volumetric data sets of the macula were obtained from 10 young (<25 yr) and 10 older (>54 yr) subjects. All young subjects and five of the older subjects had retardance values induced by the retinal pigment epithelium and Bruch's membrane (RPE-BM) complex that were just above ...

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    6. Optical Coherence Tomography for Assessment of Epithelialization in a Human Ex Vivo Wound Model

      Optical Coherence Tomography for Assessment of Epithelialization in a Human Ex Vivo Wound Model

      The ex vivo human skin wound model is a widely accepted model to study wound epithelialization. Due to a lack of animal models that fully replicate human conditions, the ex vivo model is a valuable tool to study mechanisms of wound re-epithelialization, as well as for pre-clinical testing of novel therapeutics. The current standard for assessment of wound healing in this model is histomorphometric analysis, which is labor intensive, time consuming, and requires multiple biological and technical replicates in addition to assessment of different time points. Optical Coherence Tomography (OCT) is an emerging non-invasive imaging technology originally developed for non-invasive ...

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    7. Response to Comment on “Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography”

      Response to Comment on “Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography”

      We noticed that Spahr et al. commented on our latest paper “Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography”. In their comments, they concluded that the measured retinal pulse wave velocity (rPWV) in our paper was “highly surprising and contradictory to theoretical predictions and previously published results”. However, we have some different opinions regarding their comments.

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      Mentions: Chuanqing Zhou
    8. Corneal hysteresis and anterior segment optical coherence tomography anatomical parameters in primary angle closure suspects

      Corneal hysteresis and anterior segment optical coherence tomography anatomical parameters in primary angle closure suspects

      Importance Corneal hysteresis (CH) is a dynamic marker of structural and functional changes in the cornea associated with IOP and central corneal thickness, but its utility in assessing primary angle closure suspects (PACS) has not been fully elucidated. Background This study assesses if anterior segment measurements correlate with CH in PACS patients. Design IRB-approved retrospective review of imaging and records at a university practice. Participants 63 eyes from 37 patients diagnosed as primary angle closure suspects, without other ocular pathology. Methods Every eye underwent measurements including: ocular response analyzer (ORA), anterior segment OCT, and a clinical evaluation. ORA measurements were ...

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    9. Culprit plaque characteristics in women vs men with a first ST-segment elevation myocardial infarction: In vivo optical coherence tomography insights

      Culprit plaque characteristics in women vs men with a first ST-segment elevation myocardial infarction: In vivo optical coherence tomography insights

      Background It is unclear whether more severe coronary atherosclerosis is a prerequisite to an initial acute coronary event in women vs men. Hypothesis Women may have more severe coronary atherosclerosis than men in patients with acute coronary event. Methods We used intravascular optical coherence tomography (OCT) to evaluate gender differences in culprit-plaque morphology in patients with a first ST-segment elevation myocardial infarction (STEMI).We retrospectively enrolled 211 consecutive patients who experienced a first STEMI and underwent an OCT examination of their infarct-related artery before primary percutaneous coronary intervention. Results Of the 211 patients enrolled, 162 (76.7%) were men and ...

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    10. Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography

      Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography

      In their latest publication on retinal pulse wave velocity measurement using optical co-herence tomography (OCT), Qian Li et al. propose a method to determine the pulse wave velocity in retinal arteries and veins [1]. This should enable a non-invasive determination of biomechanical properties of the vessel network, particularly the elasticity of the vessel walls [2].

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    11. Image-guided recording system for spatial and temporal mapping of neuronal activities in brain slice

      Image-guided recording system for spatial and temporal mapping of neuronal activities in brain slice

      In this study, we introduce the novel image-guided recording system (IGRS) for efficient interpretation of neuronal activities in the brain slice. IGRS is designed to combine microelectrode array (MEA) and optical coherence tomography at the customized upright microscope. It allows to record multi-site neuronal signals and image the volumetric brain anatomy in a single body configuration. For convenient interconnection between a brain image and neuronal signals, we developed the automatic mapping protocol which enables for projecting acquired neuronal signals on a brain image. In order to evaluate the performance of IGRS, hippocampal signals of the brain slice were monitored, and ...

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    12. Imaging of the lamina cribrosa and its role in glaucoma: a review

      Imaging of the lamina cribrosa and its role in glaucoma: a review

      The lamina cribrosa of the optic nerve head serves two contrasting roles; it must be porous to allow retinal ganglion cell axons to pass through, and yet at the same time, it must also provide adequate structural support to withstand the stresses and strains across it. Improvements in imaging such as optical coherence tomography image capture and image processing have allowed detailed in vivo studies of lamina cribrosa macro- and micro-architectural characteristics. This has aided our understanding of the optic nerve head as a complex biomechanical structure. In this review, we first aim to frame the biomechanical considerations of lamina ...

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    13. Polarization-multiplexed, dual-beam swept source optical coherence tomography angiography

      Polarization-multiplexed, dual-beam swept source optical coherence tomography angiography

      A polarization-multiplexed, dual-beam setup is proposed to expand the field of view for a swept source optical coherence tomography angiography (OCTA) system. This method used a Wollaston prism to split sample path light into two orthogonal-polarized beams. This allowed two beams to shine on the cornea at an angle separation of ~ 14 degrees, which led to a separation of ~ 4.2 mm on the retina. A 3-mm glass plate was inserted into one of the beam paths to set a constant path length difference between the two polarized beams so the interferogram from the two beams are coded at different ...

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    14. Multifunctional in vivo imaging for monitoring wound healing using swept-source polarization-sensitive optical coherence tomography

      Multifunctional in vivo imaging for monitoring wound healing using swept-source polarization-sensitive optical coherence tomography

      Background and Objective Wound healing involves a complex and dynamic biological process in response to tissue injury. Monitoring of the cascade of cellular events is useful for wound management and treatment. The aim of this study is to demonstrate the potential of multifunctional polarization-sensitive optical coherence tomography (PS-OCT) to longitudinally monitor the self-healing process in a murine cutaneous wound model. Materials and Methods A multi-functional PS-OCT system based on swept source OCT configuration (1,310 nm central wavelength) was designed to obtain simultaneously microstructural, blood perfusion, and birefringent information of a biological tissue in vivo . A 1-mm-diameter wound was generated ...

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    15. Role of anterior segment optical coherence tomography in angle closure disease: a review

      Role of anterior segment optical coherence tomography in angle closure disease: a review

      This article aims to review the published literature pertaining to the use of anterior segment optical coherence tomography (AS-OCT) in the evaluation of angle closure disease. Searches on the available published literature were last conducted on June 15, 2017. Rated as Level I evidence, we found that AS-OCT has shown good sensitivity and moderate diagnostic accuracy to detect narrow angles when compared with gonioscopy. AS-OCT quantitative and qualitative parameters demonstrated strong association with the presence of gonioscopically closed-angles. This technology provides an objective non-contact method of assessing the angle that is well tolerated by the patient and correlates well with ...

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    16. Optical coherence tomography of basal cell carcinoma: influence of location, subtype, observer variability and image quality on diagnostic performance

      Optical coherence tomography of basal cell carcinoma: influence of location, subtype, observer variability and image quality on diagnostic performance

      Background We previously described the principal results from an observational, prospective, multi-centre, clinical trial of the diagnostic value of optical coherence tomography (OCT) for basal cell carcinoma (BCC) in a clinical setting. In this trial, much additional useful information was gathered that warranted further analysis, presented here. Objectives To investigate the influence of candidate diagnostic criteria, OCT image quality, lesion location, and observer confidence and inter-observer variability on the diagnostic performance, and to assess potential for diagnosis of BCC subtypes. Methods A total of 234 clinically unclear “pink lesions” were evaluated in three steps: after clinical examination, after adding dermoscopy ...

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    17. Hypoxia challenge test and retinal circulation changes – a study using ocular coherence tomography angiography

      Hypoxia challenge test and retinal circulation changes – a study using ocular coherence tomography angiography

      Purpose Previous studies report that the response of retinal vessels to a decrease in oxygen (hypoxia) is vasodilation, thus increasing blood flow. We aimed to characterize the changes in retinal microvasculature induced by a mild hypoxia stress test in a healthy population, using ocular coherence tomography angiography (OCT-A) technology. Methods Interventional repeated-measures study. The standardized hypoxia challenge test (HCT) was performed to all volunteers, according to the British Thoracic Society protocol. Ocular coherence tomography angiography (OCT-A) was performed at three time-points (baseline, during HCT and 30′ posthypoxia). Macular and peripapillary vessel densities were assessed using the built-in software. To minimize ...

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    18. Paravascular abnormalities observed by spectral domain optical coherence tomography are risk factors for retinoschisis in eyes with high myopia

      Paravascular abnormalities observed by spectral domain optical coherence tomography are risk factors for retinoschisis in eyes with high myopia

      Purpose To investigate the retinal features and distribution of paravascular abnormalities (PVAs) and their relationship with retinoschisis in eyes with high myopia. Methods One hundred and fifty-two eyes of 88 patients with high myopia [refractive error greater than −6 dioptres (D) or axial length (AL) ≥26.5 mm] who had undergone comprehensive ophthalmic examinations were evaluated in this cross-sectional study. Multiple optical coherence tomography (OCT) scans were performed to study the microstructural alterations adjacent to the retinal vascular arcades and the entire macular area. The presence and distribution patterns of various PVAs, retinoschisis and the association between these parameters were ...

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    19. In vitro determination of Mexican Mestizo hair shaft diameter using optical coherence tomography

      In vitro determination of Mexican Mestizo hair shaft diameter using optical coherence tomography

      Background Mexican mestizo population has a pluriethnic mixture of Amerindian, European and African ancestry, predominant in most Latin American countries. Until now, there are no reports about hair characteristics in this population, necessary to define normal values, for hair diseases evaluation and comparison among other ethnic groups. Methods The VivoSight ® swept-source multibeam optical coherence tomography system was used to evaluate hair diameter and shape in 30 females. Three hair samples from each volunteer were measured transversely along three distances, generating nine cross-sectional images, two measurements per image and 18 measurements per patient for a total of 540 diameter measurements. Results ...

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    20. Multi-contrast Endomyocardial Imaging By Single-channel High Resolution Cross-polarization Optical Coherence Tomography

      Multi-contrast Endomyocardial Imaging By Single-channel High Resolution Cross-polarization Optical Coherence Tomography

      A single-channel high-resolution cross-polarization (CP) optical coherence tomography (OCT) system is presented for multi-contrast imaging of human myocardium in one-shot measurement. The intensity contrast and functional contrasts, including the ratio between the cross- and co- polarization channels as well as the cumulative retardation, are reconstructed from the CP-OCT readout. By comparing the CP-OCT results with histological analysis, it is shown that the system can successfully delineate micro-structures in the myocardium and differentiate the fibrotic myocardium from normal or ablated myocardium based the functional contrasts provided by the CP-OCT system. The feasibility of using A-line profiles from the two orthogonal polarization ...

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    21. Spectrally Encoded Coherence Tomography and Reflectometry (SECTR): simultaneous en face and cross-sectional imaging at 2 gigapixels-per-second

      Spectrally Encoded Coherence Tomography and Reflectometry (SECTR): simultaneous en face and cross-sectional imaging at 2 gigapixels-per-second

      Non-invasive biological imaging is crucial for understanding in vivo structure and function. Optical coherence tomography (OCT) and reflectance confocal microscopy are two of the most widely used optical modalities for exogenous contrast-free high-resolution three-dimensional imaging in non-fluorescent scattering tissues. However, sample motion remains a critical barrier to raster-scanned acquisition and reconstruction of wide-field anatomically accurate volumetric datasets. We introduce spectrally encoded coherence tomography and reflectometry (SECTR), a high-speed multimodality system for simultaneous OCT and spectrally-encoded reflectance (SER) imaging. SECTR utilizes a robust system design consisting of shared optical relays, scanning mirrors, swept-laser, and digitizer to achieve the fastest reported in ...

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    22. An overview of methods to mitigate artifacts in optical coherence tomography imaging of the skin

      An overview of methods to mitigate artifacts in optical coherence tomography imaging of the skin

      Background Optical coherence tomography (OCT) of skin delivers three-dimensional images of tissue microstructures. Although OCT imaging offers a promising high-resolution modality, OCT images suffer from some artifacts that lead to misinterpretation of tissue structures. Therefore, an overview of methods to mitigate artifacts in OCT imaging of the skin is of paramount importance. Speckle, intensity decay, and blurring are three major artifacts in OCT images. Speckle is due to the low coherent light source used in the configuration of OCT. Intensity decay is a deterioration of light with respect to depth, and blurring is the consequence of deficiencies of optical components ...

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    49-72 of 824 « 1 2 3 4 5 6 ... 33 34 35 »
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