1. Articles from Kevin C. Zhou

    1-5 of 5
    1. 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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    2. 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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    3. 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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    4. 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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    5. 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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    1-5 of 5
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  2. Topics in the News

    1. (3 articles) Duke University
    2. (2 articles) Yale University
    3. (2 articles) Michael A. Choma
    4. (2 articles) Joseph A. Izatt
    5. (1 articles) Georgia Institute of Technology
    6. (1 articles) Anthony N. Kuo
    7. (1 articles) Francisco E. Robles
    8. (1 articles) Sina Farsiu
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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 Measurement of the Shrinkage of Natural and Simulated Lesions on Root Surfaces using CP-OCT Optic-Net: A Novel Convolutional Neural Network for Diagnosis of Retinal Diseases from Optical Tomography Images Double layer sign: A new optical coherence tomography finding in active tubercular serpiginous-like choroiditis to monitor activity Influence of Epiretinal Membranes on the Retinal Nerve Fiber Layer Thickness Measured by Spectral Domain Optical Coherence Tomography in Glaucoma High signal-to-noise ratio reconstruction of low bit-depth optical coherence tomography using deep learning New Method of Quantitative Analysis of Hard Exudate Using Optical Coherence Tomography: Application in Diabetic Macular Edema Characterization and oxygen saturation study of human retinal blood vessels evaluated by spectroscopic Optical Coherence Tomography Angiography