1. Institute of Applied Physics

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    1. Mentioned In 160 Articles

    2. 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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    3. 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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    4. 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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    5. 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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    6. 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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    7. 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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    8. 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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    9. 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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    10. 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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    11. 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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    12. 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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    13. Magnetic Resonance Contrast Agents in Optical Clearing: Prospects for Multimodal Tissue Imaging

      Magnetic Resonance Contrast Agents in Optical Clearing: Prospects for Multimodal Tissue Imaging
      Skin optical clearing effect ex vivo and in vivo was achieved by topical application of low molecular weight paramagnetic magnetic resonance contrast agents. This novel feature has not been explored before. By using collimated transmittance the diffusion coefficients of three clinically used magnetic resonance contrast agents, i.e. Gadovist, Magnevist and Dotarem as well as X‐ray contrast agent Visipaque in mouse skin were determined ex vivo as (4.290 ...
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    14. Determination and correction of aberrations in full field OCT using phase gradient autofocus by maximizing the likelihood function

      Determination and correction of aberrations in full field OCT using phase gradient autofocus by maximizing the likelihood function
      A method for numerical estimation and correction of aberrations of the eye in fundus imaging with optical coherence tomography (OCT) is presented. Aberrations are determined statistically by using the estimate based on likelihood function maximization. The method can be considered as an extension of the phase gradient autofocusing algorithm in synthetic aperture radar imaging to 2D optical aberration correction. The efficacy of the proposed method has been demonstrated in OCT ...
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    15. TRANS-SEROSAL MULTIMODAL OPTICAL COHERENCE TOMOGRAPHY FOR VISUALIZATION OF MICROSTRUCTURE AND BLOOD CIRCULATION OF THE SMALL INTESTINE WALL

      TRANS-SEROSAL MULTIMODAL OPTICAL COHERENCE TOMOGRAPHY FOR VISUALIZATION OF MICROSTRUCTURE AND BLOOD CIRCULATION OF THE SMALL INTESTINE WALL
      The aim of the study was to evaluate the performance of trans-serosal multimodal OCT (MM OCT) in in vivo detecting of changes in microstructure and blood circulation of the small intestine wall caused by arteriovenous ischemia resulted from intestine strangulation. Materials and Methods. In experiments on Wistar rats (n=22), we examined the small intestine wall in vivo using MM OCT; the access to the intestine was reached through laparotomy ...
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    16. Application of Phase Correction for Compensation of Motion Artifacts in Spectral-Domain Optical Coherence Tomography

      Application of Phase Correction for Compensation of Motion Artifacts in Spectral-Domain Optical Coherence Tomography
      The application of computational methods to correct distortions in spectral-domain optical coherence tomography due to fast probe movements relative to a studied object is described. This technique is intended for use in endoscopy or in the study of external biological tissues using a handheld probe. The effectiveness of the method was confirmed experimentally.
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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.