1. Articles from Sergey G. Proskurin

    1-14 of 14
    1. An improved algorithm of structural image reconstruction with rapid scanning optical delay line for Optical Coherence Tomography

      An improved algorithm of structural image reconstruction with rapid scanning optical delay line for Optical Coherence Tomography

      A new algorithm of structural image reconstruction in Optical Coherence Tomography is described. The modified rapid scanning optical delay (RSOD) line, low numerical aperture, small angle raster scanning with consecutive averaging and multilevel digital filtering have been used to obtain high quality structural images of an onion and the nail bed of a human thumb. The proposed method significantly improves image contrast and allows visualization of small blood capillaries under the nail plate.

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    2. One specific velocity color mapping using optical coherence tomography

      One specific velocity color mapping using optical coherence tomography

      Depth resolved coherence gating along with Doppler shift detection of the carrier frequency is used for one predetermined velocity mapping in different flows. Bidirectional rapid scanning optical delay of optical coherence tomography system is applied in the reference arm. Tilted capillary entry is used as a hydrodynamic phantom to model a sign-variable flow with complex geometry. Structural and one specific velocity images are obtained from the scanning interferometer signal processing in the frequency domain using analog and digital filtering. A standard structural image is decomposed into three parts: stationary object, and positive and negative velocity distributions. The latter two show ...

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    3. Raster scanning and averaging for reducing the influence of speckles in optical coherence tomography

      Raster scanning and averaging for reducing the influence of speckles in optical coherence tomography

      The application of small-angle raster scanning and averaging in the sample arm of the Michelson interferometer in optical coherence tomography (OCT) is described. Raster averaging is used to increase the signal-to-noise ratio and to reduce the speckle noise of the 2D OCT image in diagnostics of surface layers of human skin and subcutaneous blood vessels in vivo. The method allows using low-coherence source of low-power radiation and increasing the depth of human skin coherent probing up to 1.5 – 1.8 mm. The reduction of speckle noise in the obtained OCT image for the first time allowed visualisation of subcutaneous ...

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    4. Optical Coherence-domain Imaging of Subcutaneous Human Blood Vessels in vivo

      Optical Coherence-domain Imaging of Subcutaneous Human Blood Vessels in vivo

      Experimental methods of Optical Coherence Tomography (OCT) are applied for two-dimensional mapping of subcutaneous human blood vessels. Structural images of in vivo human finger and human palm macro vessels (0.2-1.0 mm) before and after optical clearing using the modified low power rapid scanning optical delay line are presented. Images are scanned with 12 µm minimum spatial resolution. The described modifications enable to apply low power (0.4-0.5 mW), low noise broadband near infrared light source and to obtain structural images with detection of not only reflected but also multiply scattered coherence-gated photons. The achieved transcutaneous probing depth ...

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    5. Feature Of The Week 4/2/11: Doppler Optical Coherence Tomography

      Feature Of The Week 4/2/11: Doppler Optical Coherence Tomography
      Feature Of The Week 4/3/11: Doppler detection and imaging in optical coherence tomography has proven to be a powerful technique to extract important biological information. The research community has presented some very impressive results some of which can been seen by searching "Doppler" or "blood flow" or similar terms in the search box above or clicking on the category tag "Doppler". It seems that Doppler processing is one area where OCT products in the commercial world lag far behind research results which is a bit surprising given the power of the Doppler processing to bring out additional information ...
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    6. One specific velocity visualization in flows with complex geometry

      One specific velocity visualization in flows with complex geometry
      Flows with complex geometries, converging flows in a symmetric die-entry and an asymmetric oblique die-entry are investigated by means of direction sensitive one specific velocity (OSV) imaging. Near infrared, 1.3 nm, low coherence source giving resolution of about 10 micron is used for two-dimensional velocity mapping of the flows. Structural optical coherence tomography (OCT) images of a Y-junction of human subcutaneous macro blood vessels, with diameter up to 1 mm, are acquired noninvasively and in vivo. Images are acquired with transcutaneous coherence probing depth up to 1.5 - 1.6 mm. Application of the optical clearing and direction sensitive ...
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    7. Comparison of high and low coherence Doppler spectra for human subcutaneous blood flow diagnostics in vivo

      Comparison of high and low coherence Doppler spectra for human subcutaneous blood flow diagnostics in vivo
      Experimental methods of coherence-gated time domain imaging (TD-OCT), Doppler OCT and quasielastic laser light scattering are compared in terms of optimal data acquisition and processing. Low coherence methods are applied for flow visualization in hydrodynamic phantoms and in vivo. Low coherence reflection Doppler spectra are compared with laser Doppler spectra. Structural images of in vivo human subcutaneous veins with diameter of about 1 mm are demonstrated before and after optical clearing and raster averaging. Structural images of human thumb nail and ~1 mm in depth tissue underneath in the transitional OCT mode are presented. Low power rapid scanning optical delay ...
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    8. Optical clearing of in vivo human skin with hyperosmotic chemicals investigated by optical coherence tomography and near-infrared reflectance spectroscopy

      Optical clearing of in vivo human skin with hyperosmotic chemicals investigated by optical coherence tomography and near-infrared reflectance spectroscopy
      Although application of clearing agents to skin and other tissues in vitro has been studied, few have led to quantifiable results in vivo human skin. This study was to evaluate the optical clearing of human skin in vivo with topical application of hyperosmotic agents. Optical coherence tomography imaging was used to perform visual assessment of human skin during optical clearing process. Topical application of 80% glycerol and 50% DMSO to palmar skin of volunteers results in an increase in imaging depth and contrast. Imaging depth was increased to 1.1 mm after 15 minute topical treatment. The layers that consist ...
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    9. Optical coherence tomography imaging of converging flow

      Optical coherence tomography imaging of converging flow
      The experimental methods of Doppler OCT are applied for two-dimensional flow mapping of highly scattering fluid in converging flow (die entry) to demonstrate non-invasive methods to map velocity distribution and velocity profiles before and after the entry. Complex geometry flow is scanned with ~ 10x10x10 μm3 spatial resolution. Broadening of Doppler spectra obtained with slow and rapid scanning optical delay lines are compared. Structural image of human finger tip in vivo using grating based rapid OCT is presented. Velocity profiles of different shapes were obtained before and after the phantom entry. Blunted, triangular and parabolic velocity profiles as well as structural ...
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    10. Doppler optical coherence imaging of converging flow

      Doppler optical coherence imaging of converging flow
      The experimental methods of Doppler optical coherence tomography are applied for two-dimensional flow mapping of highly scattering fluid in flow with complex geometry. Converging flow (die entry) is used to demonstrate non-invasive methods to map varying velocity profiles before and after the entry. Complex geometry flow is scanned with ~10 × 10 × 10 µm3 spatial resolution. Structural images of the phantom and specific velocity images are demonstrated. A variety of velocity profiles have been obtained before and after the entry. Concave, blunted, parabolic and triangular profiles are obtained at different distances after the entry. Application of the technique to the study ...
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    11. Investigation of flows with complex geometry using coherence domain tomography

      Investigation of flows with complex geometry using coherence domain tomography
      The experimental methods of Doppler OCT are applied for two-dimensional flow mapping of highly scattering fluid in a converging flow to demonstrate non-invasive methods of velocity distribution mapping before and after the entry to a lumen of smaller diameter. A flow with complex geometry is scanned with ~10x10x10 μm3 spatial resolution. Velocity profiles of different shapes were obtained before and after the entry. Blunted, triangular and parabolic velocity profiles as well as structural images of the converging flow and images of a specific velocity are demonstrated. Broadening of Doppler spectra obtained with slow and rapid scanning optical delay lines are ...
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    12. Imaging of non-parabolic velocity profiles in converging flow with optical coherence tomography

      Imaging of non-parabolic velocity profiles in converging flow with optical coherence tomography
      The optical coherence tomography method was explored for two-dimensional flow mapping of a highly scattering fluid in flow with complex geometry. Converging flow (capillary entry) with 4:1 constriction was used for demonstration of non-invasive and remote methods of mapping varying velocity profiles. Downstream of the geometry was scanned with ~10 × 10 × 10 µm3 spatial resolution and structural imaging of the lumen and images of one particular velocity were acquired. Stable concave, blunted and parabolic profiles are obtained at different distances of the inlet length. Application of the technique for the blood circulation is also discussed.
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    13. Determination of flow velocity vector based on Doppler shift and spectrum broadening with optical coherence tomography

      Determination of flow velocity vector based on Doppler shift and spectrum broadening with optical coherence tomography
      We describe a technique that uses Doppler optical coherence tomography to estimate accurately the scattering fluid-flow velocity without a priori knowledge of the Doppler angle. Our technique is based on the combined use of the Doppler shift on the interference signal and the Doppler spectrum broadening caused by the particles moving across the probe beam. It is shown that the estimated values of the Doppler angle and average fluid velocity from the experiments agree well with the preset values.
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    14. Application of optical coherence tomography for diagnosis and measurements of glycated hemoglobin

      Application of optical coherence tomography for diagnosis and measurements of glycated hemoglobin
      The hemoglobin solution with different concentrations of glucose and, therefore, different levels of glycated hemoglobin was studied by optical coherence tomography (OCT). Obtained images of OCT were used for the measurements of refractive index of samples. Our results showed that the refractive index can be potentially applied as simple and sensitive method for the evaluation of glycated hemoglobin amount.
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    1-14 of 14
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  2. Topics in the News

    1. (14 articles) Sergey G. Proskurin
    2. (11 articles) Cranfield University
    3. (9 articles) Ruikang K. Wang
    4. (6 articles) Yonghong He
    5. (1 articles) Moscow State University
    6. (1 articles) Saratov State University
    7. (1 articles) Valery V. Tuchin
    8. (1 articles) Samsung
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    Doppler optical coherence imaging of converging flow Imaging of non-parabolic velocity profiles in converging flow with optical coherence tomography Determination of flow velocity vector based on Doppler shift and spectrum broadening with optical coherence tomography Investigation of flows with complex geometry using coherence domain tomography Optical coherence tomography imaging of converging flow Optical clearing of in vivo human skin with hyperosmotic chemicals investigated by optical coherence tomography and near-infrared reflectance spectroscopy Application of optical coherence tomography for diagnosis and measurements of glycated hemoglobin Feature Of The Week 4/2/11: Doppler Optical Coherence Tomography Optical Coherence-domain Imaging of Subcutaneous Human Blood Vessels in vivo Raster scanning and averaging for reducing the influence of speckles in optical coherence tomography Factors Associated with Changes in Retinal Layers Following Acute Optic Neuritis: A Longitudinal Study Using Optical Coherence Tomography Relationship between N95 Amplitude of Pattern Electroretinogram and Optical Coherence Tomography Angiography in Open-Angle Glaucoma