1. Articles mentioning both Ji Yi and Northwestern University

    1-24 of 31 1 2 »
    1. Visible light optical coherence tomography angiography (vis-OCTA) facilitates local microvascular oximetry in the human retina

      Visible light optical coherence tomography angiography (vis-OCTA) facilitates local microvascular oximetry in the human retina
      We report herein the first visible light optical coherence tomography angiography (vis-OCTA) for human retinal imaging. Compared to the existing vis-OCT systems, we devised a spectrometer with a narrower bandwidth to increase the spectral power density for OCTA imaging, while retaining the major spectral contrast in the blood. We achieved a 100 kHz A-line rate, the fastest acquisition speed reported so far for human retinal vis-OCT. We rigorously optimized the ...
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    2. Quantitative quality-control metrics for in vivo oximetry in small vessels by visible light optical coherence tomography angiography

      Quantitative quality-control metrics for in vivo oximetry in small vessels by visible light optical coherence tomography angiography
      Biological functions rely on local microvasculature to deliver oxygen and nutrients and carry away metabolic waste. Alterations to local oxygenation levels are manifested in diseases including cancer, diabetes mellitus, etc. The ability to quantify oxygen saturation (sO 2 ) within microvasculature in vivo to assess local tissue oxygenation and metabolic function is highly sought after. Visible light optical coherence tomography (vis-OCT) angiography has shown promise in reaching this goal. However, achieving ...
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    3. Single capillary oximetry and tissue ultrastructural sensing by dual-band dual-scan inverse spectroscopic optical coherence tomography

      Single capillary oximetry and tissue ultrastructural sensing by dual-band dual-scan inverse spectroscopic optical coherence tomography
      Measuring capillary oxygenation and the surrounding ultrastructure can allow one to monitor a microvascular niche and better understand crucial biological mechanisms. However, capillary oximetry and pericapillary ultrastructure are challenging to measure in vivo. Here, we demonstrate a novel optical imaging system, Dual-band Dual-scan Inverse Spectroscopic Optical Coherence Tomography (D2- ISOCT), that, for the first time, can simultaneously obtain the following metrics in vivo using endogenous contrast: (1) capillary-level oxygen saturation ...
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    4. In vivo broadband visible light optical coherence tomography probe enables inverse spectroscopic analysis

      In vivo broadband visible light optical coherence tomography probe enables inverse spectroscopic analysis
      We report the design and characterization of a 6 mm outer diameter pull-back circumferential scanning visible optical coherence tomography probe. The probes large visible bandwidth (500695 nm) allowed for inverse spectroscopic analysis and an axial resolution of 1.1 m 1.1m in tissue. We verify spectral imaging capabilities by measuring microsphere backscattering spectra and demonstrate in vivo spatial nanoscale characterization of tissue.
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    5. Biological tissue analysis by inverse spectroscopic optical coherence tomography

      Biological tissue analysis by inverse spectroscopic optical coherence tomography
      A method and system to measure and image the full optical scattering properties by inverse spectroscopic optical coherence tomography (ISOCT) is disclosed. Tissue is modeled as a medium with continuous refractive index (RI) fluctuation and such a fluctuation is described by the RI correlation functions. By measuring optical quantities of tissue (including the scattering power of the OCT spectrum, the reflection albedo .alpha. defined as the ratio of scattering coefficient ...
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    6. Devices, methods, and systems of functional optical coherence tomography

      Devices, methods, and systems of functional optical coherence tomography
      The present disclosure provides systems and methods for the determining a rate of change of one or more analyte concentrations in a target using non invasive non contact imaging techniques such as OCT. Generally, OCT data is acquired and optical information is extracted from OCT scans to quantitatively determine both a flow rate of fluid in the target and a concentration of one or more analytes. Both calculations can provide ...
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    7. Feature Of The Week 10/16/2016: Real-time Functional Analysis of Inertial Microfluidic Devices via Spectral Domain Optical Coherence Tomography

      Feature Of The Week 10/16/2016: Real-time Functional Analysis of Inertial Microfluidic Devices via Spectral Domain Optical Coherence Tomography
      ...tial microfluidic particle sorting devices. For more information see recent Article . Courtesy Cheng Sun from Northwestern University . Inertial microfluidic devices have recently attracted considerable interest due to t...
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    8. Real-time Functional Analysis of Inertial Microfluidic Devices via Spectral Domain Optical Coherence Tomography

      Real-time Functional Analysis of Inertial Microfluidic Devices via Spectral Domain Optical Coherence Tomography
      We report the application of spectral-domain optical coherence tomography (SD-OCT) technology that enables real-time functional analysis of sorting microparticles and cells in an inertial microfluidic device. We demonstrated high-speed, high-resolution acquisition of cross-sectional images at a frame rate of 350Hz, with a lateral resolution of 3m and an axial resolution of 1m within the microfluidic channel filled with water. We analyzed the temporal sequence of cross-sectional SD-OCT images to determine ...
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    9. Detection of extracellular matrix modification in cancer models with inverse spectroscopic optical coherence tomography

      Detection of extracellular matrix modification in cancer models with inverse spectroscopic optical coherence tomography
      In cancer biology, there has been a recent effort to understand tumor formation in the context of the tissue microenvironment. In particular, recent progress has explored the mechanisms behind how changes in the cell-extracellular matrix ensemble influence progression of the disease. The extensive use of in vitro tissue culture models in simulant matrix has proven effective at studying such interactions, but modalities for non-invasively quantifying aspects of these systems are ...
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    10. Visible-Light Optical Coherence Tomography Angiography for Monitoring Laser-Induced Choroidal Neovascularization in Mice

      Visible-Light Optical Coherence Tomography Angiography for Monitoring Laser-Induced Choroidal Neovascularization in Mice
      Purpose : This study sought to determine the earliest time-point at which evidence of choroidal neovascularization (CNV) could be detected with visible-light optical coherence tomography angiography (vis-OCTA) in a mouse model of laser-induced CNV. Methods : Visible light-OCTA was used to study laser-induced CNV at different time-points after laser injury to monitor CNV development and measure CNV lesion size. Measurements obtained from vis-OCTA angiograms were compared with histopathologic measurements from isolectin-stained choroidal ...
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    11. Dual-band optical coherence tomography using a single supercontinuum laser source

      Dual-band optical coherence tomography using a single supercontinuum laser source
      We developed a simultaneous visible-light (Vis) and near-infrared (NIR) dual-band optical coherence tomography (OCT) system using a single supercontinuum laser source. The goal was to benchmark our newly developed Vis-OCT against the well-developed NIR-OCT. The Vis-OCT subsystem operated at 91 nm full-width-at-half-maximum (FWHM) bandwidth centered at 566 nm; the NIR-OCT subsystem operated at 93 nm FWHM bandwidth centered at 841 nm. The axial resolutions were 1.8 and 4.4 ...
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    12. Devices, Methods, And Systems Of Functional Optical Coherence Tomography

      Devices, Methods, And Systems Of Functional Optical Coherence Tomography
      The present disclosure provides systems and methods for the determining a rate of change of one or more analyte concentrations in a target using non invasive non contact imaging techniques such as OCT. Generally, OCT data is acquired and optical information is extracted from OCT scans to quantitatively determine both a flow rate of fluid in the target and a concentration of one or more analytes. Both calculations can provide ...
      Read Full Article
    13. Visible light optical coherence tomography measures retinal oxygen metabolic response to systemic oxygenation

      Visible light optical coherence tomography measures retinal oxygen metabolic response to systemic oxygenation
      The lack of capability to quantify oxygen metabolism noninvasively impedes both fundamental investigation and clinical diagnosis of a wide spectrum of diseases including all the major blinding diseases such as age-related macular degeneration, diabetic retinopathy, and glaucoma. Using visible light optical coherence tomography (vis-OCT), we demonstrated accurate and robust measurement of retinal oxygen metabolic rate (rMRO 2 ) noninvasively in rat eyes. We continuously monitored the regulatory response of oxygen consumption ...
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    14. Human retinal imaging using visible-light optical coherence tomography guided by scanning laser ophthalmoscopy

      Human retinal imaging using visible-light optical coherence tomography guided by scanning laser ophthalmoscopy
      We achieved human retinal imaging using visible-light optical coherence tomography (vis-OCT) guided by an integrated scanning laser ophthalmoscopy (SLO). We adapted a spectral domain OCT configuration and used a supercontinuum laser as the illumating source. The center wavelength was 564 nm and the bandwidth was 115 nm, which provided a 0.97 m axial resolution measured in air. We characterized the sensitivity to be 86 dB with 226 W incidence ...
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    15. Measuring retinal blood flow in rats using Doppler optical coherence tomography without knowing eyeball axial length

      Measuring retinal blood flow in rats using Doppler optical coherence tomography without knowing eyeball axial length
      Purpose: Doppler optical coherence tomography (OCT) is widely used for measuring retinal blood flow. Existing Doppler OCT methods require the eyeball axial length, in which empirical values are usually used. However, variations in the axial length can create a bias unaccounted for in the retinal blood flow measurement. The authors plan to develop a Doppler OCT method that can measure the total retinal blood flow rate without requiring the eyeball ...
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    16. Measuring oxygen saturation in retinal and choroidal circulations in rats using visible light optical coherence tomography angiography

      Measuring oxygen saturation in retinal and choroidal circulations in rats using visible light optical coherence tomography angiography
      Visible light optical coherence tomography (vis-OCT) has demonstrated its capability of measuring vascular oxygen saturation (sO 2 ) in vivo . Enhanced by OCT angiography, the signal from microvasculature can be further isolated and directly used for sO 2 extraction. In this work, we extended the theoretical formulation for OCT angiography-based oximetry by incorporating the contribution from motion contrast enhancement. We presented a new method to eliminate the associated confounding variables due ...
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    17. Monte Carlo Investigation of Optical Coherence Tomography Retinal Oximetry

      Monte Carlo Investigation of Optical Coherence Tomography Retinal Oximetry
      Optical coherence tomography (OCT) oximetry explores the possibility to measure retinal hemoglobin oxygen saturation level (sO2). We investigated the accuracy of OCT retinal oximetry using Monte Carlo simulation in a commonlyused four-layer retinal model. After we determined the appropriate number of simulated photon packets, we studied the effects of blood vessel diameter, signal sampling position, physiological sO2 level, and the blood packing factor on the accuracy of sO2 estimation in ...
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    18. Measuring absolute microvascular blood flow in cortex using visible-light optical coherence tomography

      Measuring absolute microvascular blood flow in cortex using visible-light optical coherence tomography
      Understanding regulating mechanisms of cerebral blood flow (CBF) is important for clinical diagnosis and biomedical researches. We demonstrate here that phase sensitive Doppler optical coherence tomography is able to measure absolute CBF in mouse visual cortex in vivo when working in the visible-light spectral range. Both temporal and spatial profile of regional CBF variations can be resolved. We further assessed the accuracy of our method by in vitro experiments, which ...
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    19. A combined method to quantify the retinal metabolic rate of oxygen using photoacoustic ophthalmoscopy and optical coherence tomography

      A combined method to quantify the retinal metabolic rate of oxygen using photoacoustic ophthalmoscopy and optical coherence tomography
      ...d optical coherence tomography * Wei Song^1, 6, 7^, * Qing Wei^1, 7^, * Wenzhong Liu^1, 7^, * Tan Liu^1^, * Ji Yi^1^, * Nader Sheibani^2^, * Amani A. Fawzi^3^, * Robert A. Linsenmeier^1, 3, 4^, * Shuliang Jiao^5^, * Ha...
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    20. Spatially resolved optical and ultrastructural properties of colorectal and pancreatic field carcinogenesis observed by inverse spectroscopic optical coherence tomograph

      Spatially resolved optical and ultrastructural properties of colorectal and pancreatic field carcinogenesis observed by inverse spectroscopic optical coherence tomograph
      Field carcinogenesis is the initial stage of cancer progression. Understanding field carcinogenesis is valuable for both cancer biology and clinical medicine. Here, we used inverse spectroscopic optical coherence tomography to study colorectal cancer (CRC) and pancreatic cancer (PC) field carcinogenesis. Depth-resolved optical and ultrastructural properties of the mucosa were quantified from histologically normal rectal biopsies from patients with and without colon adenomas ( n = 85 ) as well as from histologically normal ...
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    21. Can OCT be sensitive to nanoscale structural alterations in biological tissue?

      Can OCT be sensitive to nanoscale structural alterations in biological tissue?
      Exploration of nanoscale tissue structures is crucial in understanding biological processes. Although novel optical microscopy methods have been developed to probe cellular features beyond the diffraction limit, nanometer-scale quantification remains still inaccessible forin situtissue. Here we demonstrate that, without actually resolving specific geometrical feature, OCT can be sensitive to tissue structural properties at the nanometer length scale. The statistical mass-density distribution in tissue is quantified by its autocorrelation function modeled ...
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    22. 1-24 of 31 1 2 »
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  2. Organizations in the News

    1. (5 articles) Boston University
    2. (2 articles) University of Wisconsin
    3. (1 articles) University of Minnesota
    4. (1 articles) Harbin Medical University
    5. (1 articles) University of Miami
  3. People in the News

    1. (19 articles) Hao F. Zhang
    2. (15 articles) Vadim Backman
    3. (3 articles) Shuliang Jiao
    4. (3 articles) Xu Li
    5. (3 articles) Cheng Sun
    6. (2 articles) Jianmin Gong