1. Articles from Natalia D. Gladkova

    1-17 of 17
    1. Optical coefficients as tools for increasing the optical coherence tomography contrast for normal brain visualization and glioblastoma detection

      Optical coefficients as tools for increasing the optical coherence tomography contrast for normal brain visualization and glioblastoma detection

      The methods used for digital processing of optical coherence tomography (OCT) and crosspolarization (CP) OCT images are focused on improving the contrast ratio of native structural OCT images. Such advances are particularly important for the intraoperative detection of glioma margins where the visual assessment of OCT images can be difficult and lead to errors. The aim of the study was to investigate the application of optical coefficients obtained from CP OCT data for the differentiation of glial tumorous tissue from a normal brain. Pseudocolor en-face OCT maps based on two optical coefficients (the commonly used rate of attenuation in the ...

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    2. Cross-polarization optical coherence tomography for brain tumor imaging

      Cross-polarization optical coherence tomography for brain tumor imaging

      This paper considers valuable visual assessment criteria for distinguishing between tumorous and non-tumorous tissues, intraoperatively, using cross-polarization OCT (CP OCT) – OCT with a functional extension, that enables detection of the polarization properties of the tissues in addition to their conventional light scattering. Materials and methods. The study was performed on 176 ex vivo human specimens obtained from 30 glioma patients. To measure the degree to which the typical parameters of CP OCT images can be matched to the actual histology, 100 images of tumors and white matter were selected for visual analysis to be undertaken by three “single-blinded” investigators. An ...

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    3. Time-related ex vivo changes in the optical properties of normal brain tissues

      Time-related ex vivo changes in the optical properties of normal brain tissues

      The aim of the study was to observe time-related changes in the optical properties of normal brain tissues as measured using cross-polarization optical coherence tomography (CP OCT). 32 ex vivo tissue samples from 16 animals (rats) were monitored under different external conditions, over a period of 1 hour after excision, to measure time-related optical changes. It was found that the optical properties of white matter were quite stable over the time scales of the experiments, while the optical properties of the gray matter could change significantly. However, these changes could be minimized by using fresh sections from samples that had ...

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    4. Optical coherence angiography without motion correction preprocessing

      Optical coherence angiography without motion correction preprocessing

      The method for vessel visualization from optical coherence tomography (OCT) data is presented. The method is based on high-frequency filtration of the normalized absolute values of the scattered field measured with OCT. It is shown that in contrast with optical coherence angiography based on the processing of complex values of a scattered field, the proposed processing does not require motion correction preprocessing while providing resulting angiographic images of comparable quality.

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    5. Quantitative nontumorous and tumorous human brain tissue assessment using microstructural co- and cross-polarized optical coherence tomography

      Quantitative nontumorous and tumorous human brain tissue assessment using microstructural co- and cross-polarized optical coherence tomography

      Optical coherence tomography (OCT) is a promising method for detecting cancer margins during tumor resection. This study focused on differentiating tumorous from nontumorous tissues in human brain tissues using cross-polarization OCT (CP OCT). The study was performed on fresh ex vivo human brain tissues from 30 patients with high- and low-grade gliomas. Different tissue types that neurosurgeons should clearly distinguish during surgery, such as the cortex, white matter, necrosis and tumorous tissue, were separately analyzed. Based on volumetric CP OCT data, tumorous and normal brain tissue were differentiated using two optical coefficients — attenuation and forward cross-scattering. Compared with white matter ...

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    6. Multimodal optical coherence tomography for in vivo imaging of brain tissue structure and microvascular network at glioblastoma

      Multimodal optical coherence tomography for in vivo imaging of brain tissue structure and microvascular network at glioblastoma

      In the case of infiltrative brain tumors the surgeon faces difficulties in determining their boundaries to achieve total resection. The aim of the investigation was to evaluate the performance of multimodal OCT (MM OCT) for differential diagnostics of normal brain tissue and glioma using an experimental model of glioblastoma. The spectral domain OCT device that was used for the study provides simultaneously two modes: cross-polarization and microangiographic OCT. The comparative analysis of the both OCT modalities images from tumorous and normal brain tissue areas concurrently with histologic correlation shows certain difference between when accordingly to morphological and microvascular tissue features.

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    7. Quantitative evaluation of atherosclerotic plaques using cross-polarization optical coherence tomography, nonlinear, and atomic force microscopy

      Quantitative evaluation of atherosclerotic plaques using cross-polarization optical coherence tomography, nonlinear, and atomic force microscopy

      A combination of approaches to the image analysis in cross-polarization optical coherence tomography (CP OCT) and high-resolution imaging by nonlinear microscopy and atomic force microscopy (AFM) at the different stages of atherosclerotic plaque development is studied. This combination allowed us to qualitatively and quantitatively assess the disorganization of collagen in the atherosclerotic arterial tissue (reduction and increase of CP backscatter), at the fiber (change of the geometric distribution of fibers in the second-harmonic generation microscopy images) and fibrillar (violation of packing and different nature of a basket-weave network of fibrils in the AFM images) organization levels. The calculated CP channel-related ...

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    8. Vessel-contrast enhancement in label-free optical coherence angiography based on phase and amplitude speckle variability

      Vessel-contrast enhancement in label-free optical coherence angiography based on phase and amplitude speckle variability

      Recently proposed in vivo label-free optical coherence angiography techniques based on phase and amplitude speckle variability often require additional signal pre- and post processing operations to enhance vessel-contrast. We observe here 1) contrast enhancement by optimizing the signal normalization/weighing before processing; 2) algorithm based on Kasai estimator for phase compensation between processed A-scans to reduce masking role of motion artifacts; and 3) image projection through the imaging depth for en face plotting. We demonstrate the efficiency of proposed additional algorithms as for the microcirculation imaging of hamsters cheek in vivo as for the preliminary microcirculation imaging of patients after ...

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    9. Robust strain mapping in optical coherence elastography by combining local phase-resolved measurements and cumulative displacement tracking

      Robust strain mapping in optical coherence elastography by combining local phase-resolved measurements and cumulative displacement tracking

      We report a novel hybrid method of robust strain mapping in compressional optical coherence elastography using combined phase measurements on sub-wavelength-scale and cumulative pixel-scale displacement tracking. This hybrid nature significantly extends the range of measurable displacements and strains in comparison with conventional direct phase-resolved measurements. As a result, the proposed strain-mapping method exhibits significantly increased robustness with respect to both additive noise and decorrelation noise produced by displacements and strains. The main advantages of the proposed approach are illustrated by numerical simulations. Experimental examples of obtained strain maps for phantoms and real biological tissues are also presented

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    10. Characterization of atherosclerotic plaques by cross-polarization optical coherence tomography

      Characterization of atherosclerotic plaques by cross-polarization optical coherence tomography

      We combined cross-polarization optical coherence tomography (CP OCT) and non-linear microscopy based on second harmonic generation (SHG) and two-photon-excited fluorescence (2PEF) to assess collagen and elastin fibers in the development of the atherosclerotic plaque (AP). The study shows potential of CP OCT for the assessment of collagen and elastin fibers condition in atherosclerotic arteries. Specifically, the additional information afforded by CP OCT, related to birefringence and cross-scattering properties of arterial tissues, may improve the robustness and accuracy of assessment about the microstructure and composition of the plaque for different stages of atherosclerosis.

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    11. Multi-modal optical imaging characterization of atherosclerotic plaques

      Multi-modal optical imaging characterization of atherosclerotic plaques

      We combined cross-polarization optical coherence tomography (CP OCT) and non-linear microscopy based on second harmonic generation (SHG) and two-photon-excited fluorescence (2PEF) to assess collagen and elastin fibers and other vascular structures in the development of atherosclerosis, including identification of vulnerable plaques, which remains an important clinical problem and imaging application. CP OCT's ability to visualize tissue birefringence and cross-scattering adds new information about the microstructure and composition of the plaque. However its interpretation can be ambiguous, because backscattering contrast may have a similar appearance to the birefringence related fringes. Our results represent a step towards minimally invasive characterization and ...

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    12. Feature Of The Week 3/13/11: Russian Scientists Investigate Cross Polarization OCT for Early Bladder Cancer Detection

      Feature Of The Week 3/13/11: Russian Scientists Investigate Cross Polarization OCT for Early Bladder Cancer Detection
      Feature Of The Week 3/13/11: This week OCT News has another exciting “Feature Of The Week” presentation of exciting scientific results on the use of co- and cross-polarization OCT information applied to early bladder cancer detection.  The work is from the prestigious Institute of Applied and Fundamental Medicine at the Nizhny Novgorod State Medical Academy and the Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russia.  Please note the authors have some excellent animation techniques so go slowly when viewing the slides so the animation can complete.   Capabilities of Cross Polarization Optical Coherence Tomography ...
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    13. Optical coherence tomography apparatus, optical fiber lateral scanner and a method for studying biological tissues in vivo

      In a method for in vivo diagnostics of a biological tissue covered with epithelium an image of the biological tissue is acquired with the aid of a beam in the visible or near IR range directed towards a biological tissue by visualizing the intensity of optical radiation backscattered by the biological tissue. The basal membrane of said biological tissue, which separates the epithelium from an underlying stroma, is identified in the acquired image and diagnostics is performed on basis of the form of the basal membrane. For diagnostics of biological tissue lining the surface of cavities and internal organs of ...
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    14. Optical coherence tomography apparatus, optical fiber lateral scanner and a method for studying biological tissues in vivo

      The present invention relates to the analysis of the internal structures of objects using optical means. According to the invention there were designed an apparatus suited for optical coherence tomography (OCT), an optical fiber lateral scanner (15), which is a part of said apparatus and is incorporated into an optical fiber probe (8), and a method for studying biological tissue in vivo, which allows for making a diagnostics of the biological tissue under study on basis of the state of the basal membrane (46). The moving part of lateral scanner (15) of sampling arm (4) of interferometer (2) is arranged ...
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    15. Optical coherent tomography apparatus, fiberoptic lateral scanner and method for studying biological tissues in vivo

      The present invention relates to the analysis of the internal structures of objects using optical means. According to the invention there were designed an apparatus suited for optical coherence tomography (OCT), an optical fiber lateral scanner (15), which is a part of said apparatus and is incorporated into an optical fiber probe (8), and a method for studying biological tissue in vivo, which allows for making a diagnostics of the biological tissue under, study on basis of the state of the basal membrane (46). The moving part of lateral scanner (15) of sampling arm (4) of interferometer (2) is arranged ...
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    16. Optical fiber interferometer with PZT scanning of interferometer arm optical length

      The invention is related to technical physics, in particular to devices for investigating the internal structure of objects and can be used in medicine for diagnostics of human organs and systems, in particular for optical coherence tomography and in technical diagnostics, for example technological process control. The invention relates to the creation of an optical-fiber interferometer, which, being used in a device for optical coherence tomography, allows one to investigate media with short time of changing of optical characteristics or its position relative to the optical probe, for example biotissues in vivo. The invention also relates to the creation of ...
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    17. Optical fiber interferometer and piezoelectric modulator

      The invention is related to technical physics, in particular to devices for investigating the internal structure of objects and can be used in medicine for diagnostics of human organs and systems, in particular for optical coherence tomography and in technical diagnostics, for example technological process control. The invention relates to the creation of an optical-fiber interferometer, which, being used in a device for optical coherence tomography, allows one to investigate media with short time of changing of optical characteristics or its position relative to the optical probe, for example biotissues in vivo. The invention also relates to the creation of ...
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    1-17 of 17
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  2. Topics in the News

    1. (17 articles) Natalia D. Gladkova
    2. (16 articles) Institute of Applied Physics
    3. (16 articles) Grigory V. Gelikonov
    4. (10 articles) Elena B. Kiseleva
    5. (8 articles) Felix I. Feldchtein
    6. (8 articles) Valentin M. Gelikonov
    7. (7 articles) Nizhny Novgorod State Medical Academy
    8. (5 articles) Elena V. Zagaynova
    9. (5 articles) Alexander M. Sergeev
    10. (5 articles) Imalux
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    Feature Of The Week 3/13/11: Russian Scientists Investigate Cross Polarization OCT for Early Bladder Cancer Detection Multi-modal optical imaging characterization of atherosclerotic plaques Robust strain mapping in optical coherence elastography by combining local phase-resolved measurements and cumulative displacement tracking Vessel-contrast enhancement in label-free optical coherence angiography based on phase and amplitude speckle variability Quantitative evaluation of atherosclerotic plaques using cross-polarization optical coherence tomography, nonlinear, and atomic force microscopy In vivo evaluation of corneal biomechanical properties by optical coherence elastography at different cross-linking irradiances The Association of Optical Coherence Tomography Results With Neuroimaging Signs and Some Clinical Parameters in Idiopathic Intracranial Hypertension Low cost scalable monolithic common path probe design for the application in endoscopic optical coherence tomography Retinal and Choroidal Vascular Changes in Eyes with Pseudoexfoliation Syndrome: a Comparative Study Using Optical Coherence Tomography Angiography Longitudinal Detection of Radiation-Induced Peripapillary and Macular Retinal Capillary Ischemia Using Optical Coherence Tomography Angiography Morphometric characteristics of the optical disc and thickness of retinal nerve fibre layer using Cirrus 5000 optical coherence tomography in healthy patients attending the National Institute of Ophthalmology Comparison of vascular parameters between normal cynomolgus macaques and healthy humans by optical coherence tomography angiography