1. Articles from Ekaterina V. Gubarkova

    1-7 of 7
    1. Histological validation of in vivo assessment of cancer tissue inhomogeneity and automated morphological segmentation enabled by Optical Coherence Elastography

      Histological validation of in vivo assessment of cancer tissue inhomogeneity and automated morphological segmentation enabled by Optical Coherence Elastography

      We present a non-invasive (albeit contact) method based on Optical Coherence Elastography (OCE) enabling the in vivo segmentation of morphological tissue constituents, in particular, monitoring of morphological alterations during both tumor development and its response to therapies. The method uses compressional OCE to reconstruct tissue stiffness map as the first step. Then the OCE-image is divided into regions, for which the Young’s modulus (stiffness) falls in specific ranges corresponding to the morphological constituents to be discriminated. These stiffness ranges (characteristic "stiffness spectra") are initially determined by careful comparison of the "gold-standard" histological data and the OCE-based stiffness map for ...

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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. 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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    4. 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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    5. 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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    6. 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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    7. 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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    1-7 of 7
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    1. (7 articles) Natalia D. Gladkova
    2. (6 articles) Institute of Applied Physics
    3. (6 articles) Nizhny Novgorod State Medical Academy
    4. (5 articles) Grigory V. Gelikonov
    5. (5 articles) Elena B. Kiseleva
    6. (3 articles) University of Toronto
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    9. (2 articles) Ontario Cancer Institute
    10. (2 articles) Valentin M. Gelikonov
    11. (1 articles) Seoul National University
    12. (1 articles) Università Vita-Salute San Raffaele
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    Multi-modal optical imaging characterization of atherosclerotic plaques Characterization of atherosclerotic plaques by cross-polarization optical coherence tomography 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 Multimodal optical coherence tomography for in vivo imaging of brain tissue structure and microvascular network at glioblastoma Cross-polarization optical coherence tomography for brain tumor imaging Histological validation of in vivo assessment of cancer tissue inhomogeneity and automated morphological segmentation enabled by Optical Coherence Elastography Diagnosis of Intraplaque Hemorrhage by High-Definition Intravascular Ultrasound and Optical Coherence Tomography Beyond plaque stenosis, into plaque composition, the answer comes from optical coherence tomography Guidelines on Optical Coherence Tomography Angiography Imaging: 2020 Focused Update Optical coherence tomography of the Tokay gecko (Gekko gecko) eye Santec announces sales launch by Alcon of SS-OCT biometer for cataract specialists in Japan under the brand MOVU