1. Articles from Kengyeh K. Chu

    1-16 of 16
    1. First Clinical Application of Low-Cost OCT

      First Clinical Application of Low-Cost OCT

      Purpose : We present the design of a new low-cost optical coherence tomography (OCT) system and compare its retinal imaging capabilities to a standard commercial system through a clinical study. Methods : A spectral-domain OCT system was designed using various cost-reduction techniques to be low-cost, highly portable, and completely stand-alone. Clinical imaging was performed on 120 eyes of 60 patients (60 eyes of normal volunteers and 60 eyes with retinal disease) using both the low-cost OCT and a Heidelberg Engineering Spectralis OCT. Contrast-to-noise ratio (CNR) was measured from resulting images to determine system performance. Results : The low-cost OCT system was successfully applied ...

      Read Full Article
    2. Light-scattering methods for tissue diagnosis

      Light-scattering methods for tissue diagnosis

      Light scattering has become a common biomedical research tool, enabling diagnostic sensitivity to myriad tissue alterations associated with disease. Light–tissue interactions are particularly attractive for diagnostics due to the variety of contrast mechanisms that can be used, including spectral, angle-resolved, and Fourier-domain detection. Photonic diagnostic tools offer further benefits in that they are non-ionizing, non-invasive, and give real-time feedback. In this review, we summarize recent innovations in light-scattering technologies, with a focus on clinical achievements over the previous ten years.

      Read Full Article
      Mentions: Duke University
    3. Real-time speckle reduction in optical coherence tomography using the dual window method

      Real-time speckle reduction in optical coherence tomography using the dual window method

      Speckle is an intrinsic noise of interferometric signals which reduces contrast and degrades the quality of optical coherence tomography (OCT) images. Here, we present a frequency compounding speckle reduction technique using the dual window (DW) method. Using the DW method, speckle noise is reduced without the need to acquire multiple frames. A ~25% improvement in the contrast-to-noise ratio (CNR) was achieved using the DW speckle reduction method with only minimal loss (~17%) in axial resolution. We also demonstrate that real-time speckle reduction can be achieved at a B-scan rate of ~21 frames per second using a graphic processing unit (GPU ...

      Read Full Article
      Mentions: Duke University
    4. Illuminating dynamic neutrophil trans-epithelial migration with micro-optical coherence tomography

      Illuminating dynamic neutrophil trans-epithelial migration with micro-optical coherence tomography

      A model of neutrophil migration across epithelia is desirable to interrogate the underlying mechanisms of neutrophilic breach of mucosal barriers. A co-culture system consisting of a polarized mucosal epithelium and human neutrophils can provide a versatile model of trans-epithelial migration in vitro , but observations are typically limited to quantification of migrated neutrophils by myeloperoxidase correlation, a destructive assay that precludes direct longitudinal study. Our laboratory has recently developed a new isotropic 1-μm resolution optical imaging technique termed micro-optical coherence tomography (μOCT) that enables 4D (x,y,z,t) visualization of neutrophils in the co-culture environment. By applying μOCT to ...

      Read Full Article
    5. Assessment of ciliary phenotype in primary ciliary dyskinesia by micro-optical coherence tomography

      Assessment of ciliary phenotype in primary ciliary dyskinesia by micro-optical coherence tomography

      Ciliary motion defects cause defective mucociliary transport (MCT) in primary ciliary dyskinesia (PCD). Current diagnostic tests do not assess how MCT is affected by perturbation of ciliary motion. In this study, we sought to use micro-optical coherence tomography (μOCT) to delineate the mechanistic basis of cilia motion defects of PCD genes by functional categorization of cilia motion. Tracheae from three PCD mouse models were analyzed using μOCT to characterize ciliary motion and measure MCT. We developed multiple measures of ciliary activity, integrated these measures, and quantified dyskinesia by the angular range of the cilia effective stroke (ARC). Ccdc39 –/– mice, with ...

      Read Full Article
    6. Flexible, high-resolution micro-optical coherence tomography endobronchial probe toward in vivo imaging of cilia

      Flexible, high-resolution micro-optical coherence tomography endobronchial probe toward in vivo imaging of cilia

      We report the design and fabrication of a flexible, longitudinally scanning high-resolution micro-optical coherence tomography (μOCT) endobronchial probe, optimized for micro-anatomical imaging in airways. The 2.4 mm diameter and flexibility of the probe allows it to be inserted into the instrument channel of a standard bronchoscope, enabling real-time video guidance of probe placement. To generate a depth-of-focus enhancing annular beam, we utilized a new fabrication method, whereby a hollow glass ferrule was angle-polished and gold-coated to produce an elongated annular reflector. We present validation data that verifies the preservation of linear scanning, despite the use of flexible materials. When ...

      Read Full Article
    7. Micro-optical coherence tomography of the mammalian cochlea

      Micro-optical coherence tomography of the mammalian cochlea

      The mammalian cochlea has historically resisted attempts at high-resolution, non-invasive imaging due to its small size, complex three-dimensional structure, and embedded location within the temporal bone. As a result, little is known about the relationship between an individual’s cochlear pathology and hearing function, and otologists must rely on physiological testing and imaging methods that offer limited resolution to obtain information about the inner ear prior to performing surgery. Micro-optical coherence tomography (μOCT) is a non-invasive, low-coherence interferometric imaging technique capable of resolving cellular-level anatomic structures. To determine whether μOCT is capable of resolving mammalian intracochlear anatomy, fixed guinea pig ...

      Read Full Article
    8. Particle-Tracking Microrheology Using Micro-Optical Coherence Tomography

      Particle-Tracking Microrheology Using Micro-Optical Coherence Tomography

      Clinical manifestations of cystic fibrosis (CF) result from an increase in the viscosity of the mucus secreted by epithelial cells that line the airways. Particle-tracking microrheology (PTM) is a widely accepted means of determining the viscoelastic properties of CF mucus, providing an improved understanding of this disease as well as an avenue to assess the efficacies of pharmacologic therapies aimed at decreasing mucus viscosity. Among its advantages, PTM allows the measurement of small volumes, which was recently utilized for an in situ study of CF mucus formed by airway cell cultures. Typically, particle tracks are obtained from fluorescence microscopy video ...

      Read Full Article
    9. In vivo imaging of airway cilia and mucus clearance with micro-optical coherence tomography

      In vivo imaging of airway cilia and mucus clearance with micro-optical coherence tomography

      We have designed and fabricated a 4 mm diameter rigid endoscopic probe to obtain high resolution micro-optical coherence tomography (µOCT) images from the tracheal epithelium of living swine. Our common-path fiber-optic probe used gradient-index focusing optics, a selectively coated prism reflector to implement a circular-obscuration apodization for depth-of-focus enhancement, and a common-path reference arm and an ultra-broadbrand supercontinuum laser to achieve high axial resolution. Benchtop characterization demonstrated lateral and axial resolutions of 3.4 μm and 1.7 μm, respectively (in tissue). Mechanical standoff rails flanking the imaging window allowed the epithelial surface to be maintained in focus without disrupting ...

      Read Full Article
    10. Feature of the Week 04/24/2016: μOCT Imaging Using Depth of Focus Extension by Self-Imaging Wavefront Division in a Common-Path Fiber Optic Probe

      Feature of the Week 04/24/2016: μOCT Imaging Using Depth of Focus Extension by Self-Imaging Wavefront Division in a Common-Path Fiber Optic Probe

      Optical coherence tomography (OCT) is an attractive medical modality due to its ability to acquire high-resolution, cross-sectional images inside the body using flexible, small-diameter, scanning fiber optic probes. Conventional, cross-sectional OCT imaging technologies have approximately 10-μm axial resolution and 30-μm lateral resolution, specifications that enable the visualization of microscopic architectural morphology. While this resolution is useful for many clinical applications, it is insufficient for resolving individual cells that characterize many diseases. To address this gap, a supercontinuum-laser-based, μm-resolution OCT (μOCT) system and a 500 μm-diameter, extended depth of focus single fiber optic probe for endoscopic and intravascular imaging ...

      Read Full Article
    11. μOCT imaging using depth of focus extension by self-imaging wavefront division in a common-path fiber optic probe

      μOCT imaging using depth of focus extension by self-imaging wavefront division in a common-path fiber optic probe

      Optical coherence tomography (OCT) is an attractive medical modality due to its ability to acquire high-resolution, cross-sectional images inside the body using flexible, small-diameter, scanning fiber optic probes. Conventional, cross-sectional OCT imaging technologies have approximately 10-μm axial resolution and 30-μm lateral resolution, specifications that enable the visualization of microscopic architectural morphology. While this resolution is useful for many clinical applications, it is insufficient for resolving individual cells that characterize many diseases. To address this gap, a supercontinuum-laser-based, μm-resolution OCT (μOCT) system and a 500 μm-diameter, extended depth of focus single fiber optic probe for endoscopic and intravascular imaging ...

      Read Full Article
    12. Combination Therapy with Cystic Fibrosis Transmembrane Conductance Regulator Modulators Augment the Airway Functional Microanatomy

      Combination Therapy with Cystic Fibrosis Transmembrane Conductance Regulator Modulators Augment the Airway Functional Microanatomy

      Recently approved therapies that modulate CFTR function have shown significant clinical benefit, but recent investigations regarding their molecular mechanism when used in combination have not been consistent with clinical results. We employed Micro-Optical Coherence Tomography (µOCT) as a novel means to assess the mechanism of action of CFTR modulators, focusing on the effects on mucociliary clearance. Primary human airway monolayers from patients with a G551D mutation responded to ivacaftor treatment with increased ion transport, airway surface liquid depth, ciliary beat frequency, and mucociliary transport rate, in addition to decreased effective viscosity of the mucus layer, a unique mechanism established by ...

      Read Full Article
    13. Innovations in Microscopic Imaging of Atherosclerosis and Valvular Disease (Book Chapter)

      Innovations in Microscopic Imaging of Atherosclerosis and Valvular Disease (Book Chapter)

      Calcific aortic valve disease (CAVD) is still an unsolved medical problem, because the pathogenesis of CAVD is poorly understood and early calcification is hard to identify. The lack of high-resolution imaging tools to study early stage disease further hampers the search for therapeutic targets. Micro-optical coherence tomography (μOCT), which is a new form of OCT, is the highest-resolution cross-sectional OCT technology available today with 1 μm resolution. We used μOCT to visualize detailed cellular and subcellular structure associated with early calcific changes in diseased human and murine aortic valves. The results suggest that μOCT imaging has the potential to provide ...

      Read Full Article
    14. Feasibility of the Assessment of Cholesterol Crystals in Human Macrophages Using Micro Optical Coherence Tomography

      Feasibility of the Assessment of Cholesterol Crystals in Human Macrophages Using Micro Optical Coherence Tomography

      The presence of cholesterol crystals is a hallmark of atherosclerosis, but until recently, such crystals have been considered to be passive components of necrotic plaque cores. Recent studies have demonstrated that phagocytosis of cholesterol crystals by macrophages may actively precipitate plaque progression via an inflammatory pathway, emphasizing the need for methods to study the interaction between macrophages and crystalline cholesterol. In this study, we demonstrate the feasibility of detecting cholesterol in macrophages in situ using Micro-Optical Coherence Tomography (µOCT), an imaging modality we have recently developed with 1-µm resolution. Macrophages containing cholesterol crystals frequently demonstrated highly scattering constituents in ...

      Read Full Article
    15. A Functional Anatomic Defect of the Cystic Fibrosis Airway

      A Functional Anatomic Defect of the Cystic Fibrosis Airway

      Rationale: The mechanisms underlying cystic fibrosis (CF) lung disease pathogenesis are unknown. Objective: To establish mechanisms linking anion transport with the functional microanatomy, we evaluated normal and CF piglet trachea, as well as adult swine trachea in the presence of selective anion inhibitors. Methods: We investigated airway functional microanatomy using micro-optical coherence tomography, a new imaging modality that concurrently quantifies multiple functional parameters of airway epithelium in a co-localized fashion. Main Results: Tracheal explants from wild type swine demonstrated a direct link between periciliary liquid (PCL) hydration and mucociliary transport (MCT) rates, a relationship frequently invoked but never experimentally confirmed ...

      Read Full Article
    16. Method for Quantitative Study of Airway Functional Microanatomy Using Micro-Optical Coherence Tomography

      Method for Quantitative Study of Airway Functional Microanatomy Using Micro-Optical Coherence Tomography

      We demonstrate the use of a high resolution form of optical coherence tomography, termed micro-OCT (μOCT), for investigating the functional microanatomy of airway epithelia. μOCT captures several key parameters governing the function of the airway surface (airway surface liquid depth, periciliary liquid depth, ciliary function including beat frequency, and mucociliary transport rate) from the same series of images and without exogenous particles or labels, enabling non-invasive study of dynamic phenomena. Additionally, the high resolution of μOCT reveals distinguishable phases of the ciliary stroke pattern and glandular extrusion. Images and functional measurements from primary human bronchial epithelial cell cultures and excised ...

      Read Full Article
    1-16 of 16
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (13 articles) Harvard University
    2. (13 articles) Massachusetts General Hospital
    3. (5 articles) University of Alabama
    4. (3 articles) Duke University
    5. (3 articles) Nanyang Technological University
    6. (2 articles) Johns Hopkins University
    7. (1 articles) Emory University
    8. (1 articles) University of North Carolina
  3. Popular Articles

  4. Picture Gallery

    Method for Quantitative Study of Airway Functional Microanatomy Using Micro-Optical Coherence Tomography A Functional Anatomic Defect of the Cystic Fibrosis Airway Feasibility of the Assessment of Cholesterol Crystals in Human Macrophages Using Micro Optical Coherence Tomography Combination Therapy with Cystic Fibrosis Transmembrane Conductance Regulator Modulators Augment the Airway Functional Microanatomy μOCT imaging using depth of focus extension by self-imaging wavefront division in a common-path fiber optic probe Feature of the Week 04/24/2016: μOCT Imaging Using Depth of Focus Extension by Self-Imaging Wavefront Division in a Common-Path Fiber Optic Probe Particle-Tracking Microrheology Using Micro-Optical Coherence Tomography Micro-optical coherence tomography of the mammalian cochlea Flexible, high-resolution micro-optical coherence tomography endobronchial probe toward in vivo imaging of cilia First Clinical Application of Low-Cost OCT Vascular and Structural Alterations of the Choroid Evaluated by Optical Coherence Tomography Angiography and Enhanced-Depth Imaging Optical Coherence Tomography in Eyes with Reticular Pseudodrusen and Soft Drusen Total venous nature of retinal deep capillary plexus inferred by continuity of prominent middle limiting membrane sign in optical coherence tomography