1. Articles from Lingfeng Yu

    1-24 of 43 1 2 »
    1. Visualization systems and methods for optimized optical coherence tomography

      Visualization systems and methods for optimized optical coherence tomography

      The present disclosure provides a visualization system for performing optimized optical coherence tomography (OCT) by determining the absolute distance between the OCT source and a sample. The present disclosure also provides a method for optimizing OCT, which includes determining an absolute distance between the OCT source and a sample using data relating to the focal length or position of an autofocus imager lens.

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      Mentions: Lingfeng Yu
    2. Subtractive en face optical coherence tomography imaging

      Subtractive en face optical coherence tomography imaging

      En face or 3D volumetric OCT imaging during ophthalmic surgery may be performed with an OCT scanning controller that interfaces to an OCT scanner used with a surgical microscope. The OCT scanner may generate en face images before and after surgical operations, such as retinal membrane peeling, are performed. Using digital subtraction on the en face images, an overlay image indicative of the changes from the surgical operations to the eye may be generated and overlaid onto an optical image displayed to a user of the surgical microscope.

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      Mentions: Lingfeng Yu
    3. Forward scanning-optical probes, circular scan patterns, offset fibers

      Forward scanning-optical probes, circular scan patterns, offset fibers

      An optical light scanning probe is presented, the probe comprising a handle, shaped for grasping by a user; a cannula, protruding from a distal portion of the handle with an outer diameter smaller than 20 gauge; an optical fiber with a distal fiber-portion off a probe-axis, configured to receive a light from a light-source at a proximal fiber-portion, and to emit the received light at the distal fiber-portion; a fixed beam forming unit, disposed at a distal portion of the cannula, configured to receive the light from the distal fiber-portion, and to deflect the received light toward a target region ...

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    4. Optical coherence tomography guided epiretinal membrane peeling

      Optical coherence tomography guided epiretinal membrane peeling

      An epiretinal membrane (ERM) visualization system includes an OCT system operable to generate an OCT image of a region of a patient's eye, the region of the patient's eye including an ERM. The ERM visualization system further includes an image processing unit operable to process the OCT image to identify the ERM by differentiating the ERM from other structures within the region of the patient's eye and generate an ERM map depicting one or more characteristics (including at least a location of a portion of the ERM within the region of the patient's eye) of the ...

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      Mentions: Lingfeng Yu
    5. Devices, systems, and methods for calibrating an OCT imaging system in a laser surgical system

      Devices, systems, and methods for calibrating an OCT imaging system in a laser surgical system

      An adjustment system for an Optical Coherence Tomography (OCT) imaging system includes an OCT light source; a beam splitter, splitting the OCT light beam into an imaging beam to an imaging arm, and a reference beam to a reference arm; a probe, guiding the imaging beam onto a target and receiving a returned imaging beam from the target; the beam splitter generating an interference beam from the returned imaging beam and a returned reference beam from the reference arm; an imaging detector, detecting the interference beam; an imaging processor, generating an OCT image from the detected interference beam; and an ...

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      Mentions: Lingfeng Yu
    6. Surgical microscope with integrated optical coherence tomography and display systems

      Surgical microscope with integrated optical coherence tomography and display systems

      An ophthalmic surgical microscope includes a beam coupler positioned along an optical path of the surgical microscope between a first eyepiece and magnifying/focusing optics, the beam coupler operable to direct the OCT imaging beam along a first portion of the optical path of the surgical microscope between the beam coupler and a patient's eye (an OCT image being generated based on a reflected portion of the OCT imaging beam). The surgical microscope additionally includes a real-time data projection unit operable to project the OCT image generated by the OCT system and a beam splitter positioned along the optical ...

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      Mentions: Lingfeng Yu
    7. Location indicator for optical coherence tomography in ophthalmic visualization

      Location indicator for optical coherence tomography in ophthalmic visualization

      An ophthalmic visualization system can include a computing device in communication with an OCT system configured to scan a surgical field to generate an OCT image. The computing device can be configured to determine locations within the surgical field corresponding to locations within the OCT image. The ophthalmic visualization system can also include an indicator mechanism in communication with the computing device and a surgical microscope configured to image the surgical field. The indicator mechanism can be configured to cause a location indicator to be positioned within a field of view of the surgical microscope. The location indicator can graphically ...

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      Mentions: Lingfeng Yu
    8. Tracking system for surgical optical coherence tomography

      Tracking system for surgical optical coherence tomography

      An OCT tracking system includes an imaging unit operable to generate a fundus image of a patient's eye and a tracking system operable to process the fundus image to determine a location of a surgical instrument inserted into the patient's eye. The OCT tracking system further includes an OCT system including an OCT light source operable to generate an OCT imaging beam and a beam scanner. Based at least in part on the determined location of the surgical instrument, the beam scanner directs the OCT imaging beam to a particular region within the patient's eye, the particular ...

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      Mentions: Lingfeng Yu
    9. Microscope-less wide field-of-view surgical OCT visualization system

      Microscope-less wide field-of-view surgical OCT visualization system

      A surgical imaging system can comprise a light source, configured to generate an imaging light beam; a beam guidance system, configured to guide the imaging light beam from the light source; a beam scanner, configured to receive the imaging light from the beam guidance system, and to generate a scanned imaging light beam; a beam coupler, configured to redirect the scanned imaging light beam; and a wide field of view (WFOV) lens, configured to guide the redirected scanned imaging light beam into a target region of a procedure eye.

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      Mentions: Lingfeng Yu
    10. Integrated OCT-refractometer system for ocular biometry

      Integrated OCT-refractometer system for ocular biometry

      A Slit-lamp-or-Microscope-Integrated-OCT-Refractometer system includes an eye-visualization system, configured to provide a visual image of an imaged region in an eye; an Optical Coherence Tomographic (OCT) imaging system, configured to generate an OCT image of the imaged region; a refractometer, configured to generate a refractive mapping of the imaged region; and an analyzer, configured to determine refractive characteristics of the eye based on the OCT image and the refractive mapping, wherein the refractometer and the OCT imaging system are integrated into the eye visualization system

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    11. Forward scanning optical probes and associated devices, systems, and methods

      Forward scanning optical probes and associated devices, systems, and methods

      Devices, systems, and methods that utilize a technique of changing a position of the set of optical fibers of the fiber bundle in cooperation with the scanning of the imaging light across a proximal surface of the fiber bundle to improve the resolution of the scanned image. In particular, a bundle actuator can be provided to change a position of the set of optical fibers of the fiber bundle in cooperation with a scanning of the imaging light across the proximal surface of the fiber bundle to cover the areas of the gaps between the optical fibers and to increase ...

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    12. Devices, Systems, And Methods For Calibrating An Oct Imaging System In A Laser Surgical System

      Devices, Systems, And Methods For Calibrating An Oct Imaging System In A Laser Surgical System

      An adjustment system for an Optical Coherence Tomography (OCT) imaging system includes an OCT light source; a beam splitter, splitting the OCT light beam into an imaging beam to an imaging arm, and a reference beam to a reference arm; a probe, guiding the imaging beam onto a target and receiving a returned imaging beam from the target; the beam splitter generating an interference beam from the returned imaging beam and a returned reference beam from the reference arm.

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      Mentions: Lingfeng Yu
    13. Inter-frame complex OCT data analysis techniques

      Inter-frame complex OCT data analysis techniques

      Techniques for collecting and processing complex OCT data to detect localized motion contrast information with enhanced accuracy and sensitivity are presented. In a preferred embodiment, vector differences between complex OCT signals taken at the same location on the sample are used to detect blood flow in the retina. Additional embodiments involving non-linear intensity weighting of the motion contrast information, normalization of the vector difference amplitudes, and calculating the absolute value of the standard deviation of Doppler signal are described. Image processing techniques to enhance the images resulting from these motion contrast techniques are also presented.

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    14. Systems And Methods For SWEPT-SOURCE Optical Coherence Tomography

      Systems And Methods For SWEPT-SOURCE Optical Coherence Tomography

      Systems and methods for increasing the duty cycle and/or producing interleaved pulses of alternating polarization states in swept-source optical coherence tomography (OCT) systems are considered. Embodiments including improved buffering, frequency selecting filter sharing among multiple SOAs, intracavity switching, and multiple wavelength bands are described. The unique polarization properties of the source configurations have advantages in speckle reduction, polarization-sensitive measurements, polarization state dependent phase shifts, spatial shifts, and temporal shifts in OCT measurements.

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    15. Methods, Systems And Applications Of Variable Imaging Depth In Fourier Domain Optical Coherence Tomography

      Methods, Systems And Applications Of Variable Imaging Depth In Fourier Domain Optical Coherence Tomography

      Systems, methods and applications for adjusting the imaging depth of a Fourier Domain optical coherence tomography system without impacting the axial resolution of the system are presented. One embodiment of the invention involves changing the sweep rate of a swept- source OCT system while maintaining the same data acquisition rate and spectral bandwidth of the source. Another embodiment involves changing the data acquisition rate of a SS-OCT system while maintaining the same sweep rate over the same spectral bandwidth. Several applications of variable imaging depth in the field of ophthalmic imaging are described.

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    16. Using optical coherence tomography to monitor effects of electromechanical reshaping in septal cartilage

      Using optical coherence tomography to monitor effects of electromechanical reshaping in septal cartilage
      Electromechanical reshaping (EMR) of cartilage is a promising noninvasive technique with potential for broad application in reconstructive surgery. EMR involves applying direct current electrical fields to localized stress regions and then initiating a series of oxidation-reduction reactions, thus effecting a shape change. Previous EMR studies have focused on macroscopic structural measurements of the shape change effect or monitoring of electrical current flow. Only limited investigation of structural changes in the tissue at the histologic level have been performed, and not in real time. This study is the first to use optical coherence tomography (OCT) to examine structural changes in cartilage ...
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    17. Optimized doppler optical coherence tomography for choroidal capillary vasculature imaging

      Optimized doppler optical coherence tomography for choroidal capillary vasculature imaging
      In this paper, we analyzed the retinal and choroidal blood vasculature in the posterior segment of the human eye with optimized color Doppler and Doppler variance optical coherence tomography. Depth-resolved structure, color Doppler and Doppler variance images were compared. Blood vessels down to capillary level were able to be obtained with the optimized optical coherence color Doppler and Doppler variance method. For in-vivo imaging of human eyes, bulkmotion induced bulk phase must be identified and removed before using color Doppler method. It was found that the Doppler variance method is not sensitive to bulk motion and the method can be ...
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    18. Real-time bulk-motion-correction free Doppler variance optical coherence tomography for choroidal capillary vasculature imaging

      Real-time bulk-motion-correction free Doppler variance optical coherence tomography for choroidal capillary vasculature imaging
      In this paper, we analyze the retinal and choroidal blood vasculature in the posterior segment of the human eye with optimized color Doppler and Doppler variance optical coherence tomography. Depth-resolved structure, color Doppler and Doppler variance images are compared. Blood vessels down to the capillary level were detected and visualized with the optimized optical coherence color Doppler and Doppler variance method. For in-vivo imaging of human eyes, bulk-motion induced bulk phase must be identified and removed before using the color Doppler method. It was found that the Doppler variance method is not sensitive to bulk-motion and the method can be ...
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    19. Spectral Doppler optical coherence tomography imaging of localized ischemic stroke in a mouse model

      Spectral Doppler optical coherence tomography imaging of localized ischemic stroke in a mouse model
      We report the use of spectral Doppler optical coherence tomography imaging (SDOCTI) for quantitative evaluation of dynamic blood circulation before and after a localized ischemic stroke in a mouse model. Rose Bengal photodynamic therapy (PDT) is used as a noninvasive means for inducing localized ischemia in cortical microvasculature of the mouse. Fast, repeated Doppler optical coherence tomography scans across vessels of interest are performed to record flow dynamic information with high temporal resolution. Doppler-angle-independent flow indices are used to quantify vascular conditions before and after the induced ischemia by the photocoagulation of PDT. The higher (or lower) flow resistive indices ...
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    20. Velocity Variation Assessment of Red Blood Cell Aggregation with Spectral Domain Doppler Optical Coherence Tomography

      Velocity Variation Assessment of Red Blood Cell Aggregation with Spectral Domain Doppler Optical Coherence Tomography
      We propose spectral domain Doppler optical coherence tomography (SD-D-OCT) to qualitatively measure red blood cell aggregation. Variance/standard deviation (SD) of the Doppler frequency spectrum in Doppler variance imaging of flowing blood under shearing conditions was developed as a new aggregation index. In in vitro microchannel-flow experiments, porcine blood at various hematocrits with aggregation characteristics induced by dextran 500 or at the presence of plasma fibrinogen was measured by a SD-D-OCT system with a spectrum centered at 1310 nm. The effects of shear rate, hematocrit, aggregation level on the SD values were investigated. The results demonstrate that Doppler variance imaging ...
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    21. Three-dimensional optical coherence tomography imaging of retinal sheet implants in live rats

      Three-dimensional optical coherence tomography imaging of retinal sheet implants in live rats
      Purpose To obtain three-dimensional images from retinal transplants in live animals and evaluate the placement and structural quality of the transplants. Methods Donor retinal sheets were isolated from E19 fetuses of transgenic rats expressing human alkaline phosphatase (hPAP), and transplanted to the subretinal space of 19–56 days old S334ter-3 rat recipients with fast retinal degeneration (average age at surgery 32 days). A total of 143 rats were imaged 1 day to 2.8 months after surgery, using a Fourier-domain optical coherence tomography (FDOCT) system, with an axial resolution of 3.5 μm. The CCD A-line integration time was set ...
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    22. Functional Doppler optical coherence tomography for cortical blood flow imaging

      Functional Doppler optical coherence tomography for cortical blood flow imaging
      Optical methods have been widely used in basic neuroscience research to study the cerebral blood flow dynamics in order to overcome the low spatial resolution associated with magnetic resonance imaging and positron emission tomography. Although laser Doppler imaging and laser speckle imaging can map out en face cortical hemodynamics and columns, depth resolution is not available. Two-photon microscopy has been used for mapping cortical activity. However, flow measurement requires fluorescent dye injection, which can be problematic. The noninvasive and high resolution tomographic capabilities of optical coherence tomography make it a promising technique for mapping depth resolved cortical blood flow. Here ...
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    23. Using optical coherence tomography to monitor effects of electromechanical reshaping in septal cartilage

      Using optical coherence tomography to monitor effects of electromechanical reshaping in septal cartilage
      Elctromechanical reshaping (EMR) of cartilage is a promising noninvasive technique with potential for broad application in reconstructive surgery. EMR involves applying direct current electrical fields to localized stress regions and initiating a series of oxidation-reduction reactions, thus effecting a shape change. Previous EMR studies have focused on macroscopic structural measurements of the shape change effect or monitoring of electrical current flow. Only limited investigation of structural changes in the tissue at the histologic level have been performed, and not in real time. This study is the first to use optical coherence tomography (OCT) to examine structural changes in cartilage during ...
      Read Full Article
    1-24 of 43 1 2 »
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    1. (39 articles) Lingfeng Yu
    2. (26 articles) UC Irvine
    3. (24 articles) Zhongping Chen
    4. (10 articles) Gangjun Liu
    5. (6 articles) Brian J. F. Wong
    6. (5 articles) National Institutes of Health
    7. (4 articles) Jun Zhang
    8. (3 articles) Utkarsh Sharma
    9. (3 articles) Matthew J. Everett
    10. (3 articles) Shuguang Guo
    11. (3 articles) Carl Zeiss Meditec
    12. (1 articles) University of Houston
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    15. (1 articles) Yale University
    16. (1 articles) Massachusetts Institute of Technology
    17. (1 articles) James G. Fujimoto
    18. (1 articles) Taner Akkin
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    High-dynamic-range quantitative phase imaging with spectral domain phase microscopy In vivo early detection of smoke-induced airway injury using three-dimensional swept-source optical coherence tomography Functional Doppler optical coherence tomography for cortical blood flow imaging Spectral Doppler optical coherence tomography imaging of localized ischemic stroke in a mouse model Real-time bulk-motion-correction free Doppler variance optical coherence tomography for choroidal capillary vasculature imaging Indiana University Receives NIH Grant for Imaging Spatial and Temporal Dynamics of Retinal Ganglion Cells University of Houston Receives NIH Grant for Structural and Molecular Phenotyping of Embryonic Development Through Multi-Modal Optical Imaging. Massachusetts Institute of Technology Receives NIH Grant for Novel Optical Diagnostics with Optical Coherence Tomography Yale University Receives a NIH Grant for Xenopus As A Model System for Hydrocephaly and Ependymal Ciliogenesis University of Minnesota Receives NIH Grant for Optical Imaging of Neural Activity Based on Lorentz Effect Skin Imaging to Inform Laser Treatments Diabetes and Fundus OCT: 1st Edition (Textbook)