1. Articles from Kevin C. Zhou

    1-7 of 7
    1. In Vivo Quantitative Analysis of Anterior Chamber White Blood Cell Mixture Composition Using Spectroscopic Optical Coherence Tomography

      In Vivo Quantitative Analysis of Anterior Chamber White Blood Cell Mixture Composition Using Spectroscopic Optical Coherence Tomography

      Anterior uveitis is the most common form of intraocular inflammation, and one of its main signs is the presence of white blood cells (WBCs) in the anterior chamber (AC). Clinically, the true composition of cells can currently only be obtained using AC paracentesis, an invasive procedure to obtain AC fluid requiring needle insertion into the AC. We previously developed a spectroscopic optical coherence tomography (SOCT) analysis method to differentiate between populations of RBCs and subtypes of WBCs, including granulocytes, lymphocytes and monocytes, both in vitro and in ACs of excised porcine eyes. We have shown that different types of WBCs ...

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    2. Spectroscopic optical coherence refraction tomography

      Spectroscopic optical coherence refraction tomography

      In optical coherence tomography (OCT), the axial resolution is often superior to the lateral resolution, which is sacrificed for long imaging depths. To address this anisotropy, we previously developed optical coherence refraction tomography (OCRT), which uses images from multiple angles to computationally reconstruct an image with isotropic resolution, given by the OCT axial resolution. On the other hand, spectroscopic OCT (SOCT), an extension of OCT, trades axial resolution for spectral resolution and hence often has superior lateral resolution. Here, we present spectroscopic OCRT (SOCRT), which uses SOCT images from multiple angles to reconstruct a spectroscopic image with isotropic spatial resolution ...

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    3. Optical coherence refraction tomography

      Optical coherence refraction tomography

      Optical coherence tomography (OCT) is a cross-sectional, micrometre-scale imaging modality with widespread clinical application. Typical OCT systems sacrifice lateral resolution to achieve long depths of focus for bulk tissue imaging, and therefore tend to have better axial than lateral resolution. Such anisotropic resolution can obscure fine ultrastructural features. Furthermore, conventional OCT suffers from refraction-induced image distortions. Here, we introduce optical coherence refraction tomography (OCRT), which extends the superior axial resolution to the lateral dimension, synthesizing undistorted cross-sectional image reconstructions from multiple conventional images acquired with angular diversity. In correcting refraction-induced distortions to register the OCT images, OCRT also achieves spatially ...

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    4. Ocular anterior chamber blood cell population differentiation using spectroscopic optical coherence tomography

      Ocular anterior chamber blood cell population differentiation using spectroscopic optical coherence tomography

      There is potential clinical significance in identifying cellular responses in the anterior chamber (AC) of the eye, which can indicate hyphema (an accumulation of red blood cells [RBCs]) or aberrant intraocular inflammation (an accumulation of white blood cells [WBCs]). In this work, we developed a spectroscopic OCT analysis method to differentiate between populations of RBCs and subtypes of WBCs, including granulocytes, lymphocytes and monocytes, both in vitro and in ACs of porcine eyes. We developed an algorithm to track single cells within OCT data sets, and extracted the backscatter reflectance spectrum of each single cell from the detected interferograms using ...

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    5. Stimulated Raman scattering spectroscopic optical coherence tomography

      Stimulated Raman scattering spectroscopic optical coherence tomography

      We integrate spectroscopic optical coherence tomography (SOCT) with stimulated Raman scattering (SRS) to enable simultaneously multiplexed spatial and spectral imaging with sensitivity to many endogenous biochemical species that play an important role in biology and medicine. The combined approach, termed SRS-SOCT, overcomes the limitations of each individual method. Ultimately, SRS-SOCT has the potential to achieve fast, volumetric, and highly sensitive label-free molecular imaging. We demonstrate the approach by imaging excised human adipose tissue and detecting the lipids’ Raman signatures in the high-wavenumber region.

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    6. Particle streak velocimetry-optical coherence tomography: a novel method for multidimensional imaging of microscale fluid flows

      Particle streak velocimetry-optical coherence tomography: a novel method for multidimensional imaging of microscale fluid flows

      We present a new OCT method for flow speed quantification and directional velocimetry: particle streak velocimetry-OCT (PSV-OCT). PSV-OCT generates two-dimensional, 2.5-vector component ( v x ,| v y |, v z ) maps of microscale flow velocity fields. Knowledge of 2.5-vector components also enables the estimation of total flow speed. The enabling insight behind PSV-OCT is that tracer particles in sparsely-seeded fluid flow trace out streaks in ( x,z,t )-space. The streak orientations in x-t and z-t yield v x and v z , respectively. The in-plane ( x-z plane) residence time yields the out-of-plane speed | v y |. Vector component values are generated ...

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    7. Improved velocimetry in optical coherence tomography using Bayesian analysis

      Improved velocimetry in optical coherence tomography using Bayesian analysis

      OCT is a popular cross-sectional microscale imaging modality in medicine and biology. While structural imaging using OCT is a mature technology in many respects, flow and motion estimation using OCT remains an intense area of research. In particular, there is keen interest in maximizing information extraction from the complex-valued OCT signal. Here, we introduce a Bayesian framework into the data workflow in OCT-based velocimetry. We demonstrate that using prior information in this Bayesian framework can significantly improve velocity estimate precision in a correlation-based, model-based framework for Doppler and transverse velocimetry. We show results in calibrated flow phantoms as well as ...

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    1-7 of 7
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  2. Topics in the News

    1. (5 articles) Duke University
    2. (4 articles) Joseph A. Izatt
    3. (2 articles) Yale University
    4. (2 articles) Anthony N. Kuo
    5. (2 articles) Michael A. Choma
    6. (2 articles) Sina Farsiu
    7. (1 articles) Georgia Institute of Technology
    8. (1 articles) Francisco E. Robles
    9. (1 articles) University of Pennsylvania
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    14. (1 articles) Jung-Yeul Kim
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    Improved velocimetry in optical coherence tomography using Bayesian analysis Particle streak velocimetry-optical coherence tomography: a novel method for multidimensional imaging of microscale fluid flows Stimulated Raman scattering spectroscopic optical coherence tomography Ocular anterior chamber blood cell population differentiation using spectroscopic optical coherence tomography Optical coherence refraction tomography Spectroscopic optical coherence refraction tomography In Vivo Quantitative Analysis of Anterior Chamber White Blood Cell Mixture Composition Using Spectroscopic Optical Coherence Tomography Assessment of Anatomical and Functional Macular Changes with Optical Coherence Tomography Angiography After Macula-Off Rhegmatogenous Retinal Detachment Repair Comparison of Spectralis and Cirrus optical coherence tomography for the detection of incomplete and complete retinal pigment epithelium and outer retinal atrophy Wide-Field Swept-Source Optical Coherence Tomography Analysis of Interocular Symmetry of Choroidal Thickness in Healthy Young Individuals Impact of cardiometabolic factors on retinal vasculature: A 3x3, 6x6 and 8x8-mm optical coherence tomography angiography study Quantitative research on the interaction between cerebral edema and peripheral cerebral blood perfusion using swept-source optical coherence tomography