1. Articles from David Levitz

    1-12 of 12
    1. Associating optical coherence tomography (OCT) data with visual imagery of a sample

      Associating optical coherence tomography (OCT) data with visual imagery of a sample

      A multi-modal imaging and optical property measurement device that is integrated into an interferometer. Data acquired by the multiple imaging modalities in parallel include measurements of single-scattered, multiple-scattered, and diffuse light that enable characterization of different ranges within different depth regions in the sample. The system includes different interferometer configurations and different imaging modalities, and has a signal-processing unit that associates and co-registers interferometric, multi-spectral, and polarization sensitive measurements to derive and analyze optical properties of a sample and enhance an image display of the sample.

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    2. Attaching Optical Coherence Tomography Systems Onto Smartphones

      Attaching Optical Coherence Tomography Systems Onto Smartphones

      A multi-modal imaging and optical property measurement device that is integrated into an interferometer. Data acquired by the multiple imaging modalities in parallel include measurements of single-scattered, multiple-scattered, and diffuse light that enable characterization of different ranges within different depth regions in the sample. The system includes different interferometer configurations and different imaging modalities, and has a signal-processing unit that associates and co-registers interferometric, multi- spectral, and polarization sensitive measurements to derive and analyze optical properties of a sample and enhance an image display of the sample.

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    3. Dermal reflectivity determined by optical coherence tomography is an indicator of epidermal hyperplasia and dermal edema within inflamed skin

      Dermal reflectivity determined by optical coherence tomography is an indicator of epidermal hyperplasia and dermal edema within inflamed skin
      Psoriasis is a common inflammatory skin disease resulting from genetic and environmental alterations of cutaneous immune responses. While numerous therapeutic targets involved in the immunopathogenesis of psoriasis have been identified, the in vivo dynamics of inflammation in psoriasis remain unclear. We undertook in vivo time course focus-tracked optical coherence tomography (OCT) imaging to noninvasively document cutaneous alterations in mouse skin treated topically with Imiquimod (IMQ), an established model of a psoriasis-like disease. Quantitative appraisal of dermal architectural changes was achieved through a two parameter fit of OCT axial scans in the dermis of the form A(x, y, z) = ρ ...
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    4. Non-destructive label-free monitoring of collagen gel remodeling using optical coherence tomography

      Non-destructive label-free monitoring of collagen gel remodeling using optical coherence tomography
      Matrix remodeling plays a fundamental role in physiological and pathological processes, as well as in tissue engineering applications. In this paper, optical coherence tomography (OCT), a non-destructive optical imaging technology, was used to image collagen gel remodeling by smooth muscle cells (SMCs). The optical scattering properties of collagen–SMC gels were characterized quantitatively by fitting OCT data to a theoretical model. Matrix remodeling over 5 days produced a 10-fold increase in the reflectivity of the collagen gels, corresponding to a decrease in scattering anisotropy from 0.91 to 0.46. The increase in reflectivity was corroborated in confocal mosaic images ...
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    5. Measuring Optical Properties of Engineered Tissues Using Optical Coherence Tomography (Thesis)

      Measuring Optical Properties of Engineered Tissues Using Optical Coherence Tomography (Thesis)
      The ability of optical imaging techniques such as optical coherence tomography (OCT) to non-destructively characterize engineered tissues has generated enormous interest recently. The engineered tissue of interest here is the collagen gel, wherein smooth muscle cells (SMCs) are embedded in a 3D collagen I matrix. This thesis focuses on characterizing collagen gels quantitatively, by measuring the optical properties – the scattering coefficient s and anisotropy factor g – from OCT data by fitting the signal to a theoretical model. μ[subscript s] and g are macroscopic physical properties that provide information on the density and size of scattering particles in the sample ...
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    6. Quantitative characterization of developing collagen gels using optical coherence tomography

      Quantitative characterization of developing collagen gels using optical coherence tomography
      Nondestructive optical imaging methods such as optical coherence tomography (OCT) have been proposed for characterizing engineered tissues such as collagen gels. In our study, OCT was used to image collagen gels with different seeding densities of smooth muscle cells (SMCs), including acellular gels, over a five-day period during which the gels contracted and became turbid with increased optical scattering. The gels were characterized quantitatively by their optical properties, specified by analysis of OCT data using a theoretical model. At 6 h, seeded cell density and scattering coefficient (µs) were correlated, with µs equal to 10.8 cm−1/(106 cells ...
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    7. Characterizing matrix remodeling in collagen gels using optical coherence tomography

      Characterizing matrix remodeling in collagen gels using optical coherence tomography
      Optical coherence tomography (OCT) has shown promise at non-destructively characterizing engineered tissues such as collagen gels. However, as the collagen gels develop, the OCT images lose contrast of structures as the gels develop, making visual assessment difficult. Our group proposed quantitatively characterizing these gels by fitting the optical properties from the OCT signals. In this paper, we imaged collagen gels seeded with smooth muscle cells (SMCs) over a 5-day period and used the data to measure their optical properties. Our results showed that over time, the reflectivity of the samples increased 10-fold, corresponding to a decrease in anisotropy factor g ...
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    8. Optically characterizing collagen gels made with different cell types

      Optically characterizing collagen gels made with different cell types
      The ability of optical imaging techniques such as optical coherence tomography (OCT) to non-destructively characterize tissue-engineered constructs has generated enormous interest recently. Collagen gels are 3D structures that represent a simple common model of many engineered tissues that contain 2 primary scatterers: collagen and cells. We are testing the ability of OCT data to characterize the remodeling of such collagen-based constructs by 3 different types of cells: vascular smooth muscle cells (SMCs), endothelial cells (ECs), and osteoblasts (OBs). Collagen gels were prepared with SMCs, ECs, and OBs with a seeding density of 1×106 cells/ml; additionally, acellular controls were ...
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    9. The effect of wavelength on optical properties extracted from images of engineered tissue

      The effect of wavelength on optical properties extracted from images of engineered tissue
      Optical imaging modalities such as confocal microscopy and optical coherence tomography (OCT) are emerging as appealing methods for non-destructive evaluation of engineered tissues. The information offered by such optical imaging methods depends on the wavelength vis-á-vis the optical scattering properties of the sample. These properties affect many factors critical to image analysis in a nonlinear and nontrivial manner. Thus, we sought to characterize the effect wavelength has on the optical properties collagen remodeled by cells at 3 common imaging wavelengths: 488, 633, and 1310 nm. To do this, we seeded smooth muscle cells (SMCs) in soluble collagen gels at a ...
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    10. Evaluating optical properties of isolated biological scatterers from confocal and low-coherence images

      In biomedical optics applications, the scattering of light by biological tissue is typically mimicked by embedding microparticles such as polystyrene microspheres or TiO within a non-scattering matrix. Such particles are well structured and give rise to uniform optical scattering properties. However ... [Proc. SPIE Int. Soc. Opt. Eng. 6870, 68700G (2008)] published Fri Feb 15, 2008.
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    11. Measuring tissue optical properties in vivo using reflectance-mode confocal microscopy and OCT

      The ability to separately measure the scattering coefficient ([mu] [cm]) and the anisotropy (g) is difficult, especially when measuring an in vivo site that can not be excised for bench-top measurements. The scattering properties ([mu] and g) can characterize the ultrastructure of a biological tissu ... [Proc. SPIE Int. Soc. Opt. Eng. 6864, 68640B (2008)] published Fri Feb 15, 2008.
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    12. Optically characterizing vascular tissue constructs made with soluble versus homogenized collagen

      The ability of optical imaging techniques such as optical coherence tomography (OCT) to non-destructively characterize tissue-engineered constructs has generated enormous interest recently. We are testing the hypothesis that OCT data can be used to characterize the cellularity of collagen-based vasc ... [Proc. SPIE Int. Soc. Opt. Eng. 6858, 68580E (2008)] published Wed Feb 6, 2008.
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    1-12 of 12
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  2. Topics in the News

    1. (11 articles) David Levitz
    2. (10 articles) Oregon Health & Science University
    3. (10 articles) Steven L. Jacques
    4. (1 articles) Technical University of Denmark (DTU)
    5. (1 articles) Ruikang K. Wang
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    The effect of wavelength on optical properties extracted from images of engineered tissue Optically characterizing collagen gels made with different cell types Characterizing matrix remodeling in collagen gels using optical coherence tomography Quantitative characterization of developing collagen gels using optical coherence tomography Non-destructive label-free monitoring of collagen gel remodeling using optical coherence tomography Dermal reflectivity determined by optical coherence tomography is an indicator of epidermal hyperplasia and dermal edema within inflamed skin Measuring Optical Properties of Engineered Tissues Using Optical Coherence Tomography (Thesis) Intravascular Imaging-Guided Percutaneous Coronary Intervention: A Universal Approach for Optimization of Stent Implantation Clinical Usefulness of a Novel Optical Coherence Tomography Procedure, “Low Molecular Weight Dextran Infusion Followed by Catheter PUSH (D-PUSH)” Optical Coherence Tomography to Guide Percutaneous Coronary Intervention of the Left Main Coronary Artery: the LEMON study Impact of optical coherence tomography findings on clinical outcomes in ST-segment elevation myocardial infarction patients: a MATRIX (Minimizing Adverse Hemorrhagic Events by Trans-radial Access Site and angioX) OCT sub-study OCTA Multilayer and Multisector Peripapillary Microvascular Modeling for Diagnosing and Staging of Glaucoma