1. Ji Yi

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    1. Mentioned In 28 Articles

    2. 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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    3. 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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    4. 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
      Inertial microfluidic devices have recently attracted considerable interest due to their unique capability of high-throughput filtration, separation, and sorting of particles and live cells in a continuous flow manner. However, the underlying mechanism is not fully understood yet, which is due to limited options for real-time three-dimensional (3D) tracking and analysis of particles and live cells in microfluidic channels. Although micro-particle image velocimetry using optical confocal microscopy can be used ...
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    5. 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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    6. 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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    7. 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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    8. 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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    9. 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
    10. Postdoctoral positions open at Boston University School of Medicine

      Postdoctoral positions open at Boston University School of Medicine
      The research is to design, manufacture optical devises, develop novel optical theory and methods for biomedical and clinical applications. The desired experience or interest includes but not limited: light scattering theory, light-tissue interaction, optics design and instrumentation, precision instrumentation, electronics design, programming, fiber optics and endoscopy. Candidate should have PhD degree in physics, optical engineering, biomedical engineering, electronic engineering, mechanical engineering or equivalent training background. Please directly contact PI at ...
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    11. 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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    12. 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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    13. 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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    14. 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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    15. 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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    16. 1-15 of 28 1 2 »
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  2. About Ji Yi

    Ji Yi

    Ji Yi is an assistant professor in Boston University, School of Medicine.  His work focuses on novel optical techniques for early disease detection, and monitoring disease progression and prognosis.  He developed various imaging methods that enable non-invasive detection of nanoscale structural alterations in tissue and the local tissue oxygen metabolism. By applying those techniques, he demonstrated the detection of the earliest form of colorectal and pancreatic cancers, colonization of metastatic breast cancer cells, and retinal diseases. He also studied the nanoscale structural changes in both cellular and extracellular components in field carcinogenesis.  See more at www.yilab.org