1. Ji Yi

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    1. Mentioned In 41 Articles

    2. Deep spectral learning for label-free optical imaging oximetry with uncertainty quantification

      Deep spectral learning for label-free optical imaging oximetry with uncertainty quantification
      Measurement of blood oxygen saturation ( s O 2 ) by optical imaging oximetry provides invaluable insight into local tissue functions and metabolism. Despite different embodiments and modalities, all label-free optical-imaging oximetry techniques utilize the same principle of s O 2 -dependent spectral contrast from haemoglobin. Traditional approaches for quantifying s O 2 often rely on analytical models that are fitted by the spectral measurements. These approaches in practice suffer from uncertainties ...
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    3. Longitudinal detection of retinal alterations by visible and near-infrared optical coherence tomography in a dexamethasone-induced ocular hypertension mouse model

      Longitudinal detection of retinal alterations by visible and near-infrared optical coherence tomography in a dexamethasone-induced ocular hypertension mouse model
      The retina, as part of the central nervous system, has distinct anatomical and structural properties for its visual function. Light scattering spectroscopy, while widely used for tissue structural characterization and disease diagnosis, has been relatively unexplored in the living retina. Recently, we have developed a fiber-based visible and near-infrared optical coherence tomography system (vnOCT) for in vivo retinal imaging, to uniquely measure a spectroscopic marker (VN ratio) sensitive to nanoscale ...
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    4. Detection of Malignancy in Ocular Surface Lesions by Inverse Spectroscopic Optical Coherence Tomography and Two-Photon Autofluorescence

      Detection of Malignancy in Ocular Surface Lesions by Inverse Spectroscopic Optical Coherence Tomography and Two-Photon Autofluorescence
      Purpose : Advanced imaging is increasingly important in the diagnosis of ocular surface malignancy. Inverse spectroscopic optical coherence tomography (ISOCT) and two-photon autofluorescence microscopy (2P-AF) are emerging techniques capable of quantifying ultrastructural and metabolic changes, respectively. We aimed to detect malignancy in ocular surface lesions using ISOCT and 2P-AF. Methods : Portions of excised specimens from patients undergoing conjunctival biopsy at Boston Medical Center were imaged by ISOCT and/or 2P-AF, and ...
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    5. 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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    6. Retinal blood flow reduction after panretinal photocoagulation in Type 2 diabetes mellitus: Doppler optical coherence tomography flowmeter pilot study

      Retinal blood flow reduction after panretinal photocoagulation in Type 2 diabetes mellitus: Doppler optical coherence tomography flowmeter pilot study
      ...graphy flowmeter pilot study. PLoS ONE 13(11): e0207288. https://doi.org/10.1371/journal.pone.0207288 Editor: Ji Yi, Boston Medical Center, Boston University School of Medicine, UNITED STATES Received: June 17, 2018; Acc...
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    7. 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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    8. Multimodal Volumetric Retinal Imaging by Oblique Scanning Laser Ophthalmoscopy (oSLO) and Optical Coherence Tomography (OCT)

      Multimodal Volumetric Retinal Imaging by Oblique Scanning Laser Ophthalmoscopy (oSLO) and Optical Coherence Tomography (OCT)
      While fluorescence imaging is widely used in ophthalmology, a large field of view (FOV) three-dimensional (3D) fluorescence retinal image is still a big challenge with the state-of-the-art retinal imaging modalities because they would require z-stacking to compile a volumetric dataset. Newer optical coherence tomography (OCT) and OCT angiography (OCTA) systems overcome these restrictions to provide three-dimensional (3D) anatomical and vascular images, but the dye-free nature of OCT cannot visualize leakage ...
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    9. Fiber-based visible and near infrared optical coherence tomography (vnOCT) enables quantitative elastic light scattering spectroscopy in human retina

      Fiber-based visible and near infrared optical coherence tomography (vnOCT) enables quantitative elastic light scattering spectroscopy in human retina
      Elastic light scattering spectroscopy (ELSS) has been proven a powerful method in measuring tissue structures with exquisite nanoscale sensitivity. However, ELSS contrast in the living human retina has been relatively underexplored, primarily due to the lack of imaging tools with a large spectral bandwidth. Here, we report a simple all fiber-based setup to implement dual-channel visible and near infrared (NIR) optical coherence tomography (vnOCT) for human retinal imaging, bridging over ...
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    10. Measurement of Flow‐Mediated Dilation of Mouse Femoral Artery in vivo by Optical Coherence Tomography

      Measurement of Flow‐Mediated Dilation of Mouse Femoral Artery in vivo by Optical Coherence Tomography
      Flow‐mediated vasodilation (FMD) is used for assessment of vascular endothelial function in humans as a predictor of cardiovascular events. It has been challenging to carry it on preclinical murine models due to the diminutive size of the femoral artery. Here, we present a new approach to accurately measure the blood velocity and femoral artery diameters of mice by acquiring Doppler optical coherence tomography (DOCT) and optical coherence tomography angiography ...
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      Mentions: Ji Yi
    11. 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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    12. Oblique scanning laser microscopy for simultaneously volumetric structural and molecular imaging using only one raster scan

      Oblique scanning laser microscopy for simultaneously volumetric structural and molecular imaging using only one raster scan
      Multi-modal three dimensional (3D) optical imaging combining both structural sensitivity and molecular specificity is highly desirable in biomedical research. In this paper, we present a method termed oblique scanning laser microscopy (OSLM) to combine optical coherence tomography (OCT), for simultaneously volumetric structural and molecular imaging with cellular resolution in all three dimensions. Conventional 3D laser scanning fluorescence microscopy requires repeated optical sectioning to create z-stacks in depth. Here, the use ...
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    13. 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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    14. 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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    15. 1-15 of 41 1 2 3 »
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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