1. Depth-resolved imaging and detection of micro-retroreflectors within biological tissue using Optical Coherence Tomography

    Explore Article opticsinfobase.org (Aug 2 2010)

    Depth-resolved imaging and detection of micro-retroreflectors within biological tissue using Optical Coherence Tomography A new approach to in vivo biosensor design is introduced, based on the use of an implantable micron-sized retroreflector-based platform and non-invasive imaging of its surface reflectivity by Optical Coherence Tomography (OCT). The possibility of using OCT for the depth-resolved imaging and detection of micro-retroreflectors in highly turbid media, including tissue, is demonstrated. The maximum imaging depth for the detection of the micro-retroreflector-based platform within the surrounding media was found to be 0.91 mm for porcine tissue and 1.65 mm for whole milk. With further development, it may be possible to utilize OCT and micro-retroreflectors as a tool for continuous ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   University of Houston   Saratov State University

  2. Imaging of mouse embryonic eye development using optical coherence tomography

    Explore Article SPIE Digital Library (Mar 2 2010)

    Imaging of mouse embryonic eye development using optical coherence tomography Congenital abnormalities are often caused by genetic disorders which alter the normal development of the eye. Embryonic eye imaging in mouse model is important for understanding of normal and abnormal eye development and can contribute to prevention and treatment of eye defects in humans. In this study, we used Swept Source Optical Coherence Tomography (SS-OCT) to image eye structure in mouse embryos at 12.5 to 17.5 days post coitus (dpc). The imaging depth of the OCT allowed us to visualize the whole eye globe at these stages. Different ocular tissues including lens, cornea, eyelids, and hyaloid vasculature were visualized. These ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   Baylor College of Medicine   University of Houston

  3. Measurement of vibrations induced on the surface of crystalline eye lens using PhS-SDOCT

    Explore Article SPIE Digital Library (Mar 2 2010)

    Measurement of vibrations induced on the surface of crystalline eye lens using PhS-SDOCT Experimental assessment of stiffness of crystalline lens of the eye can help in understanding several ocular diseases. Studies have shown that stiffness of the eye lens increases with age that might contribute to loss of accommodation. The stiffness of the lens could be assessed by measuring mechanically induced surface waves propagating on its surface. Here we present preliminary results on phase sensitive spectral domain optical coherence tomography (PhS-SDOCT) measurements of the vibrations induced on surface of an eye lens. The system shows an axial resolution of 8 µm, phase sensitivity of 0.01 radians, imaging depth of up to 3.4 mm ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   Stepan A. Baranov   University of Houston

  4. Quantification of microbubbles in blood with phase-sensitive SSOCT

    Explore Article SPIE Digital Library (Feb 23 2010)

    Quantification of microbubbles in blood with phase-sensitive SSOCT We have developed a phase stabilized swept source optical coherence tomography (PhS-SSOCT), that shows an axial resolution of 10 µm, phase sensitivity of 0.04 radians, imaging depth of up to 6 mm in air and a scanning speed of 20 kHz for a single A-line. In this paper, the PhS-SSOCT is applied to quantify gas microbubbles in blood in vitro. The results indicate that the system is able to detect bubbles of diameters greater than 10 µm using the structural image and the microbubbles of diameter less than 10 µm could be detected using the temporal phase response. Images of ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   University of Houston

  5. Multiple-cardiac-cycle noise reduction in dynamic optical coherence tomography of the embryonic heart and vasculature

    Explore Article opticsinfobase.org (Nov 20 2009)

    Multiple-cardiac-cycle noise reduction in dynamic optical coherence tomography of the embryonic heart and vasculature Recent progress in optical coherence tomography (OCT) allows imaging dynamic structures and fluid flow within scattering tissue, such as the beating heart and blood flow in mouse embryos. Accurate representation and analysis of these dynamic behaviors require reducing the noise of the acquired data. Although noise can be reduced by averaging multiple neighboring pixels in space or time, such operations reduce the effective spatial or temporal resolution that can be achieved. We have developed a computational postprocessing technique to restore image sequences of cyclically moving structures that preserves frame rate and spatial resolution. The signal-to-noise ratio (SNR) is improved by ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   Baylor College of Medicine   University of Houston

  6. Monitoring of glucose permeability in monkey skin in vivo using Optical Coherence Tomography

    Explore Article www3.interscience.wiley.com (Oct 12 2009)

    Topical trans-dermal delivery of drugs has proven to be a promising route for treatment of many dermatological diseases. The aim of this study is to monitor and quantify the permeability rate of glucose solutions in rhesus monkey skin noninvasively in vivo as a primate model for drug diffusion. A time-domain Optical Coherence Tomography (OCT) system was used to image the diffusion of glucose in the skin of anesthetized monkeys for which the permeability rate was calculated. From 5 experiments on 4 different monkeys, the permeability for glucose-20% was found to be (4.41 ± 0.28) 10-6 cm/sec. The results suggest that ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   University of Houston   Saratov State University

  7. Live imaging of rat embryos with Doppler swept-source optical coherence tomography

    Explore Article Scitation (Oct 1 2009)

    The rat has long been considered an excellent system to study mammalian embryonic cardiovascular physiology, but has lacked the extensive genetic tools available in the mouse to be able to create single gene mutations. However, the recent establishment of rat embryonic stem cell lines facilitates the generation of new models in the rat embryo to link changes in physiology with altered gene function to define the underlying mechanisms behind congenital cardiovascular birth defects. Along with the ability to create new rat genotypes there is a strong need for tools to analyze phenotypes with high spatial and temporal resolution. Doppler OCT ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   University of Houston

  8. Phase-sensitive swept source optical coherence tomography for imaging and quantifying of microbubbles in clear and scattering media

    Explore Article Scitation (May 20 2009)

    phase resolved system based on swept source optical coherence tomography (SSOCT) called as phase-sensitive SSOCT to detect and quantify gas microbubbles in aqueous and tissue simulated media is developed. The structural images of gas microbubbles are obtained using conventional SSOCT, while common path SSOCT was used to perform the phase-sensitive measurements. The system shows an axial resolution of 10 µm, a phase sensitivity of 0.03 rad, an imaging depth of up to 6 mm in air, and a scanning speed of 20 kHz for a single A-line. The structural images of the bubbles show an accuracy of 10 µm, whereas ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   University of Houston   Saratov State University

  9. Hemodynamic measurements from individual blood cells in early mammalian embryos with Doppler swept source OCT

    Explore Article opticsinfobase.org (Mar 18 2009)

    Hemodynamic measurements from individual blood cells in early mammalian embryos with Doppler swept source OCT The most common and lethal birth defects affect the cardiovascular (CV) system. The mouse is a superior model for identifying and understanding mammalian CV birth defects, but there is a great need for tools that can detect early and subtle deficiencies in cardiac function in mouse embryos. We combined swept source optical coherence tomography (SS-OCT) with live mouse embryo culture protocols to generate structural two-dimensional and three-dimensional imaging and hemodynamic measurements in a live 8.5 day embryo just a few hours after the beginning of a heartbeat. Our data show that individual circulating blood cells can be visualized with structural ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   Baylor College of Medicine   University of Houston

  10. Effect of temperature on permeation of low-density lipoprotein particles through human carotid artery tissues

    Explore Article www3.interscience.wiley.com (Mar 11 2009)

    Quantification of the diffusion of small molecules and large lipid transporting lipoproteins across arterial tissues could be useful in elucidating the mechanism(s) of atherosclerosis. Optical coherence tomography (OCT) was used to determine the effect of temperature on the rate of diffusion of glucose and low-density lipoproteins (LDL) in human carotid endarterectomy tissue in vitro. The permeability rate for glucose was calculated to be (3.51 ± 0.27) × 10-5 cm/s (n = 13) at 20 °C, and (3.70 ± 0.44) × 10-5 cm/s (n = 5) at 37 °C; for LDL the rate was (2.42 ± 0.33) × 10-5 cm/s (n ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   University of Houston   Mohamad G. Ghosn

  11. The nonlinear relationship between concentration of analyte and its permeability coefficient in ocular tissues

    Explore Article SPIE Digital Library (Feb 23 2009)

    The nonlinear relationship between concentration of analyte and its permeability coefficient in ocular tissues Monitoring and quantifying the permeability of different drugs and chemical solutions through ocular tissues is of great importance due to its potential use in pharmacological research. In this study, Optical Coherence Tomography, a relatively new innovation in biomedical imaging was used for the functional imaging of glucose diffusion in the sclera of the eye. The permeability coefficient for different glucose concentrations was quantified non-destructively in order to compare the effect of glucose concentration on its rate of diffusion. In these in vitro experiments, fresh New Zealand white rabbit eyes were imaged during the diffusion of different glucose concentrations (10, 15, ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   Valery V. Tuchin   Mohamad G. Ghosn

  12. Quantifying the effect of milli-molar glucose concentration on thickness of rabbit cornea with optical coherence tomography

    Explore Article SPIE Digital Library (Feb 20 2009)

    The cornea contributes about 65% of the eye's ability to refract light. Thus, any fluctuation in corneal thickness can cause noticeable changes in vision. The presence of glucose molecules induces a driving force for water to leave the collagen fibrils in the cornea due to the concentration gradient created, thus changing its thickness. In this study, the effect of various milli-molar glucose concentrations on corneal thickness was explored using Optical Coherence Tomography. Whole rabbit eyes were placed in a specially designed dish while immersed in saline to ensure proper hydration of the eye. The cornea was imaged for 10 minutes. ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   Mohamad G. Ghosn   University of Houston

  13. Enhanced OCT imaging of embryonic tissue with optical clearing

    Explore Article SPIE Digital Library (Feb 20 2009)

    Optical coherence tomography (OCT) holds great promise as a routine research tool for 3-D analysis of mammalian embryos. However, despite the depth penetration afforded by this imaging modality, light attenuation in tissues imposes limitations. Here we studied the optical clearing effect of differen ... [Proc. SPIE 7168, 71682C (2009)] published Fri Feb 20, 2009. (Read Full Article)

    Comment on Article Mentions:   Valery V. Tuchin   Baylor College of Medicine   Kirill V. Larin

  14. Imaging of cardiovascular dynamics in early mouse embryos with swept source optical coherence tomography

    Explore Article SPIE Digital Library (Feb 19 2009)

    Congenital cardiovascular defects are very common, occurring in 1% of live births, and cardiovascular failures are the leading cause of birth defect-related deaths in infants. To improve diagnostics, prevention and treatment of cardiovascular abnormalities, we need to understand not only how cells f ... [Proc. SPIE 7168, 71680E (2009)] published Thu Feb 19, 2009. (Read Full Article)

    Comment on Article Mentions:   Baylor College of Medicine   Kirill V. Larin   University of Houston

  15. Optical coherence tomography in estimating molecular diffusion of drugs and analytes in ocular tissues

    Explore Article SPIE Digital Library (Feb 18 2009)

    Aside from other ocular drug delivery methods, topical application and follow up drug diffusion through the cornea and sclera of the eye remain the favored method, as they impose the least pain and discomfort to the patient. However, this delivery route suffers from the low permeability of epithelia ... [Proc. SPIE 7163, 71631H (2009)] published Wed Feb 18, 2009. (Read Full Article)

    Comment on Article Mentions:   Valery V. Tuchin   Mohamad G. Ghosn   Kirill V. Larin

  16. Live imaging of blood flow in mammalian embryos using Doppler swept-source optical coherence tomography

    Explore Article SPIE Digital Library (Dec 21 2008)

    Irina V. Larina, Narendran Sudheendran, Mohamad Ghosn et al. Studying hemodynamic changes during early mammalian embryonic development is critical for further advances in prevention, diagnostics, and treatment of congenital cardiovascular (CV) birth defects and diseases. Doppler optical coherence tomography (OCT) has been shown to provide sensitive measuremen ... [J. Biomed. Opt. 13, 060506 (2008)] published Fri Dec 19, 2008. (Read Full Article)

    Comment on Article Mentions:   Alex E. Cable   Thorlabs   Kirill V. Larin

  17. Assessing molecular diffusion in tissues using optical coherence tomography

    Explore Article Home: SPIE.org (Jun 20 2008)

    Assessing molecular diffusion in tissues using optical coherence tomography Advanced imaging near the surface of tissues could assist the development of novel therapeutic agents, drug delivery systems, and diagnostic tests. (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   University of Houston   Valery V. Tuchin

  18. Concentration effect on the diffusion of glucose in ocular tissues

    Explore Article ScienceDirect (Jun 17 2008)

    In this study, optical coherence tomography (OCT) was utilized in the functional imaging of glucose diffusion through scleral tissues. Permeability coefficients for different concentrations of glucose were quantified nondestructively. Obtained results indicate an inverse proportionality between the permeability coefficient and the concentration of the analyte in epithelial tissues: in-depth diffusion of solutions with lower glucose concentration was faster than those with a higher concentration. The permeability coefficient decreased from (1.67±0.17)×10−5 cm/s of 10% glucose solution to (5.08±0.23)×10−6 cm/s of 25% glucose solution. The dependence of the permeability on the concentration of hyperosmotic analytes could potentially be used in various basic ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   University of Houston   Saratov State University

  19. Functional imaging and assessment of the glucose diffusion rate in epithelial tissues in optical coherence tomography

    Explore Article Institute of Physics (Jun 15 2008)

    Functional imaging, monitoring and quantitative description of glucose diffusion in epithelial and underlying stromal tissues in vivo and controlling of the optical properties of tissues are extremely important for many biomedical applications including the development of noninvasive or minimally invasive glucose sensors as well as for therapy and diagnostics of various diseases, such as cancer, diabetic retinopathy, and glaucoma. Recent progress in the development of a noninvasive molecular diffusion biosensor based on optical coherence tomography (OCT) is described. The diffusion of glucose was studied in several epithelial tissues both in vitro and in vivo. Because OCT provides depth-resolved imaging of ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   Saratov State University   Valery V. Tuchin

  20. Ultra-sensitive monitoring of analyte concentrations using phase sensitive spectral domain OCT

    Explore Article SPIE Digital Library (Jun 9 2008)

    V. G. R. Manne, R. K. Manapuram, N. Sudheendran et al. The refractive index is a basic optical property of a medium which is of great importance in physics, chemistry and most of biomedical applications. In our current study we monitor the change in refractive index for aqueous solutions of glucose, CaCl, MgCl, NaCl, KCl and urea using a phase sensitive ... [Proc. SPIE 6791, 67910A (2008)] published Mon Jun 9, 2008. (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   University of Houston

  21. The effect of solution concentration on diffusion in scleral tissues

    Explore Article SPIE Digital Library (Jun 9 2008)

    Mohamad G. Ghosn, Esteban F. Carbajal, Natasha A. Befrui et al. The calculation of permeability coefficient of analytes could potentially be used in a variety of basic science and clinical fields, as well as advanced diagnostic imaging. Before this can occur, a more thorough understanding of the diffusion rate of analytes in biological tissues is needed. For thi ... [Proc. SPIE 6791, 679107 (2008)] published Mon Jun 9, 2008. (Read Full Article)

    Comment on Article Mentions:   Mohamad G. Ghosn   Kirill V. Larin   University of Houston

  22. Differential permeability rate and percent clearing of glucose in different regions in rabbit sclera

    Explore Article SPIE Digital Library (Apr 21 2008)

    Mohamad G. Ghosn, Esteban F. Carbajal, Natasha A. Befrui et al. Imaging of biological tissues with optical coherence tomography (OCT) poses a great interest for its capability to noninvasively outline subsurface microstructures within tissues. However, a major limitation for many optical imaging techniques is inadequate depth penetration of light in turbid media ... [J. Biomed. Opt. 13, 021110 (2008)] published Mon Apr 21, 2008. (Read Full Article)

    Comment on Article Mentions:   Saratov State University   Mohamad G. Ghosn   University of Houston

  23. Three-dimensional imaging of artificial fingerprint by optical coherence tomography

    Explore Article SPIE Digital Library (Mar 17 2008)

    Kirill V. Larin and Yezeng Cheng Fingerprint recognition is one of the popular used methods of biometrics. However, due to the surface topography limitation, fingerprint recognition scanners are easily been spoofed, e.g. using artificial fingerprint dummies. Thus, biometric fingerprint identification devices need to be more accurat ... [Proc. SPIE Int. Soc. Opt. Eng. 6944, 69440M (2008)] published Mon Mar 17, 2008. (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   University of Houston

  24. Permeability of hyperosmotic agent in normal and atherosclerotic vascular tissues

    Explore Article SPIE Digital Library (Feb 28 2008)

    Noninvasive cardiovascular imaging could lead to the early detection and timely treatment of complex atherosclerotic lesions responsible for major cardiovascular events. Recent investigations have suggested that optical coherence tomography (OCT) is an ideal diagnostic tool due to the high resolution this technology achieves in discriminating the different features of atherosclerotic lesions based on structural imaging. We explore the capability of OCT for functional imaging of normal and atherosclerotic aortic tissues based on time- and depth-resolved quantification of the permeability of biomolecules through these tissues. The permeability coefficient of 20% aqueous solution of glucose was found to be (6.80±0.18)×10−6 cm/s in ... (Read Full Article)

    Comment on Article Mentions:   Kirill V. Larin   University of Houston   Mohamad G. Ghosn

  25. Quantifying permeability of glucose in normal and atherosclerotic pig aorta in vitro using optical coherence tomography

    Explore Article SPIE Digital Library (Feb 18 2008)

    Mohamad G. Ghosn, Esteban Carbajal, Natasha Befrui et al. High in-depth resolution imaging, such as Optical Coherence Tomography, could be the next frontier in noninvasive quantification of diffusion in epithelial tissues. In this study we employed OCT in a method that could help differentiate various forms of atherosclerosis and distinguish between normal ... [Proc. SPIE Int. Soc. Opt. Eng. 6847, 68471E (2008)] published Mon Feb 18, 2008. (Read Full Article)

    Comment on Article Mentions:   Mohamad G. Ghosn   Kirill V. Larin   University of Houston

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