1. Institute of Applied Physics

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    1. Mentioned In 164 Articles

    2. Brain white matter morphological structure correlation with its optical properties estimated from optical coherence tomography (OCT) data

      Brain white matter morphological structure correlation with its optical properties estimated from optical coherence tomography (OCT) data
      A pilot post-mortem study identifies a strong correlation between the attenuation coefficient estimated from the OCT data and some morphological features of the sample, namely the number of nuclei in the field of view of the histological image and the fiber structural parameter introduced in the study to quantify the difference in the myelinated fibers arrangements. The morphological features were identified from the histopathological images of the sample taken from ...
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    3. OCT-Guided Surgery for Gliomas: Current Concept and Future Perspectives

      OCT-Guided Surgery for Gliomas: Current Concept and Future Perspectives
      Optical coherence tomography (OCT) has been recently suggested as a promising method to obtain in vivo and real-time high-resolution images of tissue structure in brain tumor surgery. This review focuses on the basics of OCT imaging, types of OCT images and currently suggested OCT scanner devices and the results of their application in neurosurgery. OCT can assist in achieving intraoperative precision identification of tumor infiltration within surrounding brain parenchyma by ...
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    4. Single-cell all-optical coherence elastography with optical tweezers

      Single-cell all-optical coherence elastography with optical tweezers
      The elastic properties of cells are important for many of their functions, however the development of label free noninvasive cellular elastography method is a challenging topic. We present a novel single-cell all-optical coherence elastography method that combines optical tweezers producing mechanical excitation on the cell membrane or organelle and phase-sensitive optical coherence microscopy measuring sample response and determining its mechanical properties. The method allows living cells imaging with a lateral ...
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    5. An Improved Analytical Model of a Spectrometer for Optical Coherence Tomography

      An Improved Analytical Model of a Spectrometer for Optical Coherence Tomography
      We present an improved analytical model of a spectrometer for optical coherence tomography (OCT), which more accurately describes the OCT in-depth sensitivity fall-off. The model considers the intrinsic spectral resolution of the dispersive element and the influence of additional components (inequidistance-correcting prism). The model is validated by experimental data obtained both from other studies and our own experiments. The influence of the frequency response of the CCD electrical circuit and ...
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    6. Simulating scan formation in multimodal optical coherence tomography: angular-spectrum formulation based on ballistic scattering of arbitrary-form beams

      Simulating scan formation in multimodal optical coherence tomography: angular-spectrum formulation based on ballistic scattering of arbitrary-form beams
      We present a computationally highly efficient full-wave spectral model of OCT-scan formation with the following features: allowance of arbitrary phase-amplitude profile of illuminating beams; absence of paraxial approximation; utilization of broadly used approximation of ballistic scattering by discrete scatterers without limitations on their density/location and scattering strength. The model can easily incorporate the wave decay, dispersion, measurement noises with given signal-to-noise ratios and arbitrary inter-scan displacements of scatterers. We ...
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    7. Optical coherence tomography, intravascular ultrasound or angiography guidance for distal left main coronary stenting. The ROCK cohort II study

      Optical coherence tomography, intravascular ultrasound or angiography guidance for distal left main coronary stenting. The ROCK cohort II study
      Objectives: to test the safety and efficacy of intravascular imaging and specifically optical coherence tomography (OCT) as a diagnostic tool for left main angioplasty and analyze the mid-term outcome accordingly. Background: Clinical data and international guidelines recommend the use of intravascular imaging ultrasound (IVUS) to guide left main (LM) angioplasty. Despite early experience using OCT in this setting is encouraging, the evidence supporting its use is still limited. Methods: ROCK ...
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    8. Lymph vessels visualization from Optical Coherence Tomography data using depth-resolved attenuation coefficient calculation

      Lymph vessels visualization from Optical Coherence Tomography data using depth-resolved attenuation coefficient calculation
      Multimodal Optical Coherent Tomography grows popularity with researchers and clinicians over the past decade. One of the modalities is lymphangiography, which allows visualization of the lymphatic vessel networks within OCT imaging volume. In the present study, it is shown that lymphatic vessel visualization obtained from the depth-resolved attenuation coefficient distributions, corrected for the noise, shows improved contrast and detail in comparison with previously proposed approaches. We also argue that the ...
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    9. Recognition of individual scatterers against the noise background in the optical coherence tomography image

      Recognition of individual scatterers against the noise background in the optical coherence tomography image
      The problem of recognising single sparsely located scatterers against the noise background in the image obtained by the method of optical coherence tomography (OCT) is considered. An identification method based on the use of specific scanning features upon OCT image registration and on the statistical analysis of image fragments is proposed. The efficiency of the method is demonstrated experimentally in the diagnosis of otitis media with effusion. The approach can ...
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    10. Prospects of Intraoperative Multimodal OCT Application in Patients with Acute Mesenteric Ischemia

      Prospects of Intraoperative Multimodal OCT Application in Patients with Acute Mesenteric Ischemia
      Introduction: Despite the introduction of increasingly multifaceted diagnostic techniques and the general advances in emergency abdominal and vascular surgery, the outcome of treatment of patients with acute impaired intestinal circulation remains unsatisfactory. The non-invasive and high-resolution technique of optical coherence tomography (OCT) can be used intraoperatively to assess intestine viability and associated conditions that frequently emerge under conditions of impaired blood circulation. This study aims to demonstrate the effectiveness of ...
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    11. Capability of physically reasonable OCT-based differentiation between intact brain tissues, human brain gliomas of different WHO grades, and glioma model 101.8 from rats

      Capability of physically reasonable OCT-based differentiation between intact brain tissues, human brain gliomas of different WHO grades, and glioma model 101.8 from rats
      Optical coherence tomography (OCT) of the ex vivo rat and human brain tissue samples is performed. The set of samples comprises intact white and gray matter, as well as human brain gliomas of the World Health Organization (WHO) Grades I-IV and glioma model 101.8 from rats. Analysis of OCT signals is aimed at comparing the physically reasonable properties of tissues, and determining the attenuation coefficient, parameter related to effective ...
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    12. Slow axis displacement correction for stripe artefact removal in optical coherence angiography

      Slow axis displacement correction for stripe artefact removal in optical coherence angiography
      The method for displacement correction along the slow axis of optical coherence tomography (OCT) data volumes is presented. The method is based on the recursive replacement of the next displaced OCT measurements by the weighted summation of itself and the previous OCT measurement in the slow axis dimension already corrected for the displacement. The values of the appropriate weight multipliers were defined from the local correlation of the two measurements ...
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    13. Calibration of Lateral Scanning in Optical Coherence Tomography Devices

      Calibration of Lateral Scanning in Optical Coherence Tomography Devices
      Methods for determining the dependence of the lateral-scan coordinate on the A-scan number from tomographic images of test samples are investigated and techniques for compensating for horizontal distortions of tomographic images caused by uneven speed of the probing-beam displacement are proposed. An opal-glass Ronchi ruling and an inclined flat surface of the volume-scattering plate were used as test samples .
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    14. Depth-resolved approach for the attenuation coefficient calculation from the Optical Coherence Tomography data and its application for the brain imaging

      Depth-resolved approach for the attenuation coefficient calculation from the Optical Coherence Tomography data and its application for the brain imaging
      Optical coherence tomography (OCT) is a promising tool for intraoperative tissue morphology determination. Several studies suggest that the attenuation coefficient, derived from the OCT images can differentiate between normal and tumorous tissues, as well as between gray and white brain matter. The methods used for attenuation coefficient derivation in these studies follow the assumption that the optical properties of the specimen are uniform within the OCT imaging depth range. Although ...
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    15. Strain and elasticity imaging in compression optical coherence elastography: the two‐decade perspective and recent advances

      Strain and elasticity imaging in compression optical coherence elastography: the two‐decade perspective and recent advances
      Quantitative mapping of deformation and elasticity in optical coherence tomography has attracted much attention of researchers during the last two decades. However, despite intense effort it took ~15years to demonstrate optical coherence elastography (OCE) as a practically useful technique. Similarly to medical ultrasound, where elastography was first realized using the quasi‐static compression principle and later shear‐wave‐based systems were developed, in OCE these two approaches also developed in ...
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    16. 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 Youngs modulus (stiffness) falls in specific ranges corresponding to ...
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  2. About Institute of Applied Physics

    Institute of Applied Physics

    Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS) was created by a Decree of the Soviet Government on July 28, 1976. Annually the IAP RAS performs about 350 scientific projects, funded by federal special programs, academic, industry, international and other programs and projects. Among the most prominent achievements of the Institute of Applied Physics RAS are the invention of gyrotrons and gyroklystrons and their upgrading to a high technical level, the development of effective methods to convert and transport powerful electromagnetic radiation, the elaboration of physical principles for excitation and reception of low-frequency sound fields in the ocean and the creation of hardware for hydroacoustics and long-term acoustical monitoring in the ocean, complexes for research of noise radiation characteristics of moving objects, the development of high-rate growth and precision processing of water-soluble crystals, developmet of optical coherent tomography to image biotissue structures and designing an optical tomograph for medical diagnostics of human internal organs  See IAP RAS OCT link HERE.