1
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De La Hoz A, Villegas L, Marcos S, Birkenfeld JS. A simple computational model for scleral stiffness assessments via air-puff deformation OCT. Front Bioeng Biotechnol 2024; 12:1426060. [PMID: 39144479 PMCID: PMC11323745 DOI: 10.3389/fbioe.2024.1426060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 07/16/2024] [Indexed: 08/16/2024] Open
Abstract
Introduction: The mechanical properties of the sclera are related to its structural function, and changes to these properties are believed to contribute to pathologies such as myopia. Air-puff deformation imaging is a tool that uses an imaging system coupled with an air-puff excitation source to induce and measure deformation in a tissue in vivo. Typically used for the study of the cornea's mechanical properties and IOP, this tool has been proposed as a method to evaluate scleral stiffness. Methods: In this work, we present a computational model of the rabbit eye to assess scleral deformation under air-puff. Parametric studies were conducted to evaluate the effects of material properties, intraocular pressure, and other parameters on the deformation response. Output from the model was also compared to experimental measurements of air-puff deformation in rabbit eyes under varying IOP. Results: Central deformation response was found to be most influenced by material properties of the sclera (at site of air-puff and posterior), thickness, and IOP, whereas deformation profile was most influenced by material properties. Experimental and simulated IOP dependence were found to be similar (RMSE = 0.13 mm). Discussion: Scleral APDI could be a useful tool for quick in vivo assessment of scleral stiffness.
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Affiliation(s)
- Andres De La Hoz
- Instituto de Óptica “Daza de Valdés”, Consejo Superior de Investigaciones Científicas (IO-CSIC), Madrid, Spain
| | - Lupe Villegas
- Instituto de Óptica “Daza de Valdés”, Consejo Superior de Investigaciones Científicas (IO-CSIC), Madrid, Spain
| | - Susana Marcos
- Center for Visual Science, The Institute of Optics, Flaum Eye Institute, University of Rochester, Rochester, NY, United States
| | - Judith S. Birkenfeld
- Instituto de Óptica “Daza de Valdés”, Consejo Superior de Investigaciones Científicas (IO-CSIC), Madrid, Spain
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2
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Li K, Yang G, Chang S, Yao J, He C, Lu F, Wang X, Wang Z. Comprehensive assessment of the anterior segment in refraction corrected OCT based on multitask learning. BIOMEDICAL OPTICS EXPRESS 2023; 14:3968-3987. [PMID: 37799701 PMCID: PMC10549746 DOI: 10.1364/boe.493065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/28/2023] [Accepted: 06/28/2023] [Indexed: 10/07/2023]
Abstract
Anterior segment diseases are among the leading causes of irreversible blindness. However, a method capable of recognizing all important anterior segment structures for clinical diagnosis is lacking. By sharing the knowledge learned from each task, we proposed a fully automated multitask deep learning method that allows for simultaneous segmentation and quantification of all major anterior segment structures, including the iris, lens, cornea, as well as implantable collamer lens (ICL) and intraocular lens (IOL), and meanwhile for landmark detection of scleral spur and iris root in anterior segment OCT (AS-OCT) images. In addition, we proposed a refraction correction method to correct for the true geometry of the anterior segment distorted by light refraction during OCT imaging. 1251 AS-OCT images from 180 patients were collected and were used to train and test the model. Experiments demonstrated that our proposed network was superior to state-of-the-art segmentation and landmark detection methods, and close agreement was achieved between manually and automatically computed clinical parameters associated with anterior chamber, pupil, iris, ICL, and IOL. Finally, as an example, we demonstrated how our proposed method can be applied to facilitate the clinical evaluation of cataract surgery.
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Affiliation(s)
- Kaiwen Li
- School of Electronic Science and Engineering,
University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
| | - Guangqian Yang
- School of Electronic Science and Engineering,
University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
| | - Shuimiao Chang
- Department of Cataract, Shanxi Eye Hospital Affiliated to Shanxi Medical University, Taiyuan, Shanxi 030001, China
| | - Jinhan Yao
- Department of Cataract, Shanxi Eye Hospital Affiliated to Shanxi Medical University, Taiyuan, Shanxi 030001, China
| | - Chong He
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
| | - Fang Lu
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
| | - Xiaogang Wang
- Department of Cataract, Shanxi Eye Hospital Affiliated to Shanxi Medical University, Taiyuan, Shanxi 030001, China
| | - Zhao Wang
- School of Electronic Science and Engineering,
University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
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3
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Garcia-Marin YF, Alonso-Caneiro D, Fisher D, Vincent SJ, Collins MJ. Patch-based CNN for corneal segmentation of AS-OCT images: Effect of the number of classes and image quality upon performance. Comput Biol Med 2023; 152:106342. [PMID: 36481759 DOI: 10.1016/j.compbiomed.2022.106342] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 10/24/2022] [Accepted: 11/16/2022] [Indexed: 12/03/2022]
Abstract
Anterior segment optical coherence tomography (AS-OCT) is a fundamental ophthalmic imaging technique. AS-OCT images can be examined by experts and segmented to provide quantitative metrics that inform clinical decision making. Manual segmentation of these images is time-consuming and subjective, encouraging software developers in the field to automate segmentation procedures. Traditional programing segmentation approaches are being replaced by deep learning methods, which have shown state-of-the-art performance in AS-OCT image analysis. In this study, a method based on patch-based convolutional neural networks (CNN) was used to segment the three main boundaries of the cornea: the epithelium, Bowman's layer, and the endothelium. To assess the effect of the number of classes on performance, the model was designed as a patch-based boundary classifier using 4 and 8 classes. The effect of image quality was also assessed using different data distributions during the training process. While the Dice coefficient and probability revealed greater precision for the 8 class models, the boundary error metric indicated comparable performance. Additionally, for 8 class models, the image quality test had only a small negative effect on performance, which may be an indication of the robustness of the model and could also suggest that the data augmentation methods did not show significant improvement. These findings contribute to the development of automatic segmentation techniques for AS-OCT images, since patch-based methods have been largely unexplored in favor of other deep learning techniques. The overall performance of the proposed method is comparable to other well-established segmentation methods.
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Affiliation(s)
- Yoel F Garcia-Marin
- Queensland University of Technology (QUT), Contact Lens and Visual Optics Laboratory, Centre for Vision and Eye Research, School of Optometry and Vision Science, Kelvin Grove, Qld, 4059, Australia.
| | - David Alonso-Caneiro
- Queensland University of Technology (QUT), Contact Lens and Visual Optics Laboratory, Centre for Vision and Eye Research, School of Optometry and Vision Science, Kelvin Grove, Qld, 4059, Australia
| | - Damien Fisher
- Queensland University of Technology (QUT), Contact Lens and Visual Optics Laboratory, Centre for Vision and Eye Research, School of Optometry and Vision Science, Kelvin Grove, Qld, 4059, Australia
| | - Stephen J Vincent
- Queensland University of Technology (QUT), Contact Lens and Visual Optics Laboratory, Centre for Vision and Eye Research, School of Optometry and Vision Science, Kelvin Grove, Qld, 4059, Australia
| | - Michael J Collins
- Queensland University of Technology (QUT), Contact Lens and Visual Optics Laboratory, Centre for Vision and Eye Research, School of Optometry and Vision Science, Kelvin Grove, Qld, 4059, Australia
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4
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Hackmann MJ, Elliot JG, Green FHY, Cairncross A, Cense B, McLaughlin RA, Langton D, James AL, Noble PB, Donovan GM. Requirements and limitations of imaging airway smooth muscle throughout the lung in vivo. Respir Physiol Neurobiol 2022; 301:103884. [PMID: 35301143 DOI: 10.1016/j.resp.2022.103884] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 02/08/2022] [Accepted: 03/05/2022] [Indexed: 11/18/2022]
Abstract
Clinical visualization and quantification of the amount and distribution of airway smooth muscle (ASM) in the lungs of individuals with asthma has major implications for our understanding of airway wall remodeling as well as treatments targeted at the ASM. This paper theoretically investigates the feasibility of quantifying airway wall thickness (focusing on the ASM) throughout the lung in vivo by means of bronchoscopic polarization-sensitive optical coherence tomography (PS-OCT). Using extensive human biobank data from subjects with and without asthma in conjunction with a mathematical model of airway compliance, we define constraints that airways of various sizes pose to any endoscopic imaging technique and how this is impacted by physiologically relevant processes such as constriction, inflation and deflation. We identify critical PS-OCT system parameters and pinpoint parts of the airway tree that are conducive to successful quantification of ASM. We further quantify the impact of breathing and ASM contraction on the measurement error and recommend strategies for standardization and normalization.
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Affiliation(s)
- Michael J Hackmann
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Engineering, University of Western Australia, Perth, Western Australia, Australia.
| | - John G Elliot
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia; West Australian Sleep Disorders Research Institute, Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Francis H Y Green
- Department of Pathology and Laboratory Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Alvenia Cairncross
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Barry Cense
- School of Engineering, University of Western Australia, Perth, Western Australia, Australia; Department of Mechanical Engineering, Yonsei University, Seoul, South-Korea
| | - Robert A McLaughlin
- School of Engineering, University of Western Australia, Perth, Western Australia, Australia; Australian Research Council Centre of Excellence for Nanoscale Biophotonics, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, South Australia, Australia; Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, South Australia, Australia
| | - David Langton
- Faculty of Medicine, Nursing and Allied Health, Monash University, Melbourne, Victoria, Australia
| | - Alan L James
- West Australian Sleep Disorders Research Institute, Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Medical School, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, New Zealand
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5
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Alexopoulos P, Madu C, Wollstein G, Schuman JS. The Development and Clinical Application of Innovative Optical Ophthalmic Imaging Techniques. Front Med (Lausanne) 2022; 9:891369. [PMID: 35847772 PMCID: PMC9279625 DOI: 10.3389/fmed.2022.891369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/23/2022] [Indexed: 11/22/2022] Open
Abstract
The field of ophthalmic imaging has grown substantially over the last years. Massive improvements in image processing and computer hardware have allowed the emergence of multiple imaging techniques of the eye that can transform patient care. The purpose of this review is to describe the most recent advances in eye imaging and explain how new technologies and imaging methods can be utilized in a clinical setting. The introduction of optical coherence tomography (OCT) was a revolution in eye imaging and has since become the standard of care for a plethora of conditions. Its most recent iterations, OCT angiography, and visible light OCT, as well as imaging modalities, such as fluorescent lifetime imaging ophthalmoscopy, would allow a more thorough evaluation of patients and provide additional information on disease processes. Toward that goal, the application of adaptive optics (AO) and full-field scanning to a variety of eye imaging techniques has further allowed the histologic study of single cells in the retina and anterior segment. Toward the goal of remote eye care and more accessible eye imaging, methods such as handheld OCT devices and imaging through smartphones, have emerged. Finally, incorporating artificial intelligence (AI) in eye images has the potential to become a new milestone for eye imaging while also contributing in social aspects of eye care.
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Affiliation(s)
- Palaiologos Alexopoulos
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
| | - Chisom Madu
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
- Center for Neural Science, College of Arts & Science, New York University, New York, NY, United States
| | - Joel S. Schuman
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
- Center for Neural Science, College of Arts & Science, New York University, New York, NY, United States
- Department of Electrical and Computer Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
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6
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Göb M, Pfeiffer T, Draxinger W, Lotz S, Kolb JP, Huber R. Continuous spectral zooming for in vivo live 4D-OCT with MHz A-scan rates and long coherence. BIOMEDICAL OPTICS EXPRESS 2022; 13:713-727. [PMID: 35284187 PMCID: PMC8884208 DOI: 10.1364/boe.448353] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/20/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
We present continuous three-dimensional spectral zooming in live 4D-OCT using a home-built FDML based OCT system with 3.28 MHz A-scan rate. Improved coherence characteristics of the FDML laser allow for imaging ranges up to 10 cm. For the axial spectral zoom feature, we switch between high resolution and long imaging range by adjusting the sweep range of our laser. We present a new imaging setup allowing for synchronized adjustments of the imaging range and lateral field of view during live OCT imaging. For this, a novel inline recalibration algorithm was implemented that enables numerical k-linearization of the raw OCT fringes for every frame instead of every volume. This is realized by acquiring recalibration data within the dead time of the raster scan at the turning points of the fast axis scanner. We demonstrate in vivo OCT images of fingers and hands at different resolution modes and show real three-dimensional zooming during live 4D-OCT. A three-dimensional spectral zooming feature for live 4D-OCT is expected to be a useful tool for a wide range of biomedical, scientific and research applications, especially in OCT guided surgery.
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Affiliation(s)
- Madita Göb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Tom Pfeiffer
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Optores GmbH, Gollierstr. 70, 80339 Munich, Germany
| | - Wolfgang Draxinger
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Simon Lotz
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Jan Philip Kolb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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7
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High speed, long range, deep penetration swept source OCT for structural and angiographic imaging of the anterior eye. Sci Rep 2022; 12:992. [PMID: 35046423 PMCID: PMC8770693 DOI: 10.1038/s41598-022-04784-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/13/2021] [Indexed: 11/24/2022] Open
Abstract
This study reports the development of prototype swept-source optical coherence tomography (SS-OCT) technology for imaging the anterior eye. Advances in vertical-cavity surface-emitting laser (VCSEL) light sources, signal processing, optics and mechanical designs, enable a unique combination of high speed, long range, and deep penetration that addresses the challenges of anterior eye imaging. We demonstrate SS-OCT with a 325 kHz A-scan rate, 12.2 µm axial resolution (in air), and 15.5 mm depth range (in air) at 1310 nm wavelength. The ultrahigh 325 kHz A-scan rate not only facilitates biometry measurements by minimizing acquisition time and thus reducing motion, but also enables volumetric OCT for comprehensive structural analysis and OCT angiography (OCTA) for visualizing vasculature. The 15.5 mm (~ 11.6 mm in tissue) depth range spans all optical surfaces from the anterior cornea to the posterior lens capsule. The 1310 nm wavelength range enables structural OCT and OCTA deep in the sclera and through the iris. Achieving high speed and long range requires linearizing the VCSEL wavenumber sweep to efficiently utilize analog-to-digital conversion bandwidth. Dual channel recording of the OCT and calibration interferometer fringe signals, as well as sweep to sweep wavenumber compensation, is used to achieve invariant 12.2 µm (~ 9.1 µm in tissue) axial resolution and optimum point spread function throughout the depth range. Dynamic focusing using a tunable liquid lens extends the effective depth of field while preserving the lateral resolution. Improved optical and mechanical design, including parallax “split view” iris cameras and stable, ergonomic patient interface, facilitates accurate instrument positioning, reduces patient motion, and leads to improved imaging data yield and measurement accuracy. We present structural and angiographic OCT images of the anterior eye, demonstrating the unique imaging capabilities using representative scanning protocols which may be relevant to future research and clinical applications.
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8
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Bouma B, de Boer J, Huang D, Jang I, Yonetsu T, Leggett C, Leitgeb R, Sampson D, Suter M, Vakoc B, Villiger M, Wojtkowski M. Optical coherence tomography. NATURE REVIEWS. METHODS PRIMERS 2022; 2:79. [PMID: 36751306 PMCID: PMC9901537 DOI: 10.1038/s43586-022-00162-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Optical coherence tomography (OCT) is a non-contact method for imaging the topological and internal microstructure of samples in three dimensions. OCT can be configured as a conventional microscope, as an ophthalmic scanner, or using endoscopes and small diameter catheters for accessing internal biological organs. In this Primer, we describe the principles underpinning the different instrument configurations that are tailored to distinct imaging applications and explain the origin of signal, based on light scattering and propagation. Although OCT has been used for imaging inanimate objects, we focus our discussion on biological and medical imaging. We examine the signal processing methods and algorithms that make OCT exquisitely sensitive to reflections as weak as just a few photons and that reveal functional information in addition to structure. Image processing, display and interpretation, which are all critical for effective biomedical imaging, are discussed in the context of specific applications. Finally, we consider image artifacts and limitations that commonly arise and reflect on future advances and opportunities.
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Affiliation(s)
- B.E. Bouma
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,Institute for Medical Engineering and Physics, Massachusetts Institute of Technology, Cambridge, MA, USA,Harvard Medical School, Boston, MA, USA,Corresponding author:
| | - J.F. de Boer
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - D. Huang
- Casey Eye Institute, Oregon Health and Science University, Portland, OR, USA
| | - I.K. Jang
- Harvard Medical School, Boston, MA, USA,Cardiology Division, Massachusetts General Hospital, Boston, MA, USA
| | - T. Yonetsu
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - C.L. Leggett
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - R. Leitgeb
- Institute of Medical Physics, University of Vienna, Wien, Austria
| | - D.D. Sampson
- School of Physics and School of Biosciences and Medicine, University of Surrey, Guildford, United Kingdom
| | - M. Suter
- Harvard Medical School, Boston, MA, USA,Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - B. Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,Harvard Medical School, Boston, MA, USA
| | - M. Villiger
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,Harvard Medical School, Boston, MA, USA
| | - M. Wojtkowski
- Institute of Physical Chemistry and International Center for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland,Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun, Poland
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9
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Bronte-Ciriza D, Birkenfeld JS, de la Hoz A, Curatolo A, Germann JA, Villegas L, Varea A, Martínez-Enríquez E, Marcos S. Estimation of scleral mechanical properties from air-puff optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2021; 12:6341-6359. [PMID: 34745741 PMCID: PMC8548012 DOI: 10.1364/boe.437981] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/15/2021] [Accepted: 08/15/2021] [Indexed: 05/11/2023]
Abstract
We introduce a method to estimate the biomechanical properties of the porcine sclera in intact eye globes ex vivo, using optical coherence tomography that is coupled with an air-puff excitation source, and inverse optimization techniques based on finite element modeling. Air-puff induced tissue deformation was determined at seven different locations on the ocular globe, and the maximum apex deformation, the deformation velocity, and the arc-length during deformation were quantified. In the sclera, the experimental maximum deformation amplitude and the corresponding arc length were dependent on the location of air-puff excitation. The normalized temporal deformation profile of the sclera was distinct from that in the cornea, but similar in all tested scleral locations, suggesting that this profile is independent of variations in scleral thickness. Inverse optimization techniques showed that the estimated scleral elastic modulus ranged from 1.84 ± 0.30 MPa (equatorial inferior) to 6.04 ± 2.11 MPa (equatorial temporal). The use of scleral air-puff imaging holds promise for non-invasively investigating the structural changes in the sclera associated with myopia and glaucoma, and for monitoring potential modulation of scleral stiffness in disease or treatment.
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Affiliation(s)
- David Bronte-Ciriza
- Instituto de Óptica "Daza de Valdés", Consejo Superior de Investigaciones Científicas (IO-CSIC), Madrid, Spain
- CNR - IPCF, Istituto per i Processi Chimico-Fisici, Messina, Italy
- Co-first authors
| | - Judith S Birkenfeld
- Instituto de Óptica "Daza de Valdés", Consejo Superior de Investigaciones Científicas (IO-CSIC), Madrid, Spain
- Co-first authors
| | - Andrés de la Hoz
- Instituto de Óptica "Daza de Valdés", Consejo Superior de Investigaciones Científicas (IO-CSIC), Madrid, Spain
| | - Andrea Curatolo
- Instituto de Óptica "Daza de Valdés", Consejo Superior de Investigaciones Científicas (IO-CSIC), Madrid, Spain
- International Centre for Translational Eye Research, Warsaw, Poland
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - James A Germann
- Instituto de Óptica "Daza de Valdés", Consejo Superior de Investigaciones Científicas (IO-CSIC), Madrid, Spain
| | - Lupe Villegas
- Instituto de Óptica "Daza de Valdés", Consejo Superior de Investigaciones Científicas (IO-CSIC), Madrid, Spain
| | - Alejandra Varea
- Instituto de Óptica "Daza de Valdés", Consejo Superior de Investigaciones Científicas (IO-CSIC), Madrid, Spain
| | - Eduardo Martínez-Enríquez
- Instituto de Óptica "Daza de Valdés", Consejo Superior de Investigaciones Científicas (IO-CSIC), Madrid, Spain
| | - Susana Marcos
- Instituto de Óptica "Daza de Valdés", Consejo Superior de Investigaciones Científicas (IO-CSIC), Madrid, Spain
- Center for Visual Science, The Institute of Optics, Flaum Eye Institute, University of Rochester, NY 14642, USA
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10
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Ultimate Spatial Resolution Realisation in Optical Frequency Domain Reflectometry with Equal Frequency Resampling. SENSORS 2021; 21:s21144632. [PMID: 34300374 PMCID: PMC8309478 DOI: 10.3390/s21144632] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/28/2021] [Accepted: 06/29/2021] [Indexed: 11/17/2022]
Abstract
A method based on equal frequency resampling is proposed to suppress laser nonlinear frequency sweeping for the ultimate spatial resolution in optical frequency domain reflectometry. Estimation inaccuracy of the sweeping frequency distribution caused by the finite sampling rate in the auxiliary interferometer can be efficiently compensated by the equal frequency resampling method. With the sweeping range of 130 nm, a 12.1 µm spatial resolution is experimentally obtained. In addition, the sampling limitation of the auxiliary interferometer-based correction is discussed. With a 200 m optical path delay in the auxiliary interferometer, a 21.3 µm spatial resolution is realised at the 191 m fibre end. By employing the proposed resampling and a drawing tower FBG array to enhance the Rayleigh backscattering, a distributed temperature sensing over a 105 m fibre with a sensing resolution of 1 cm is achieved. The measured temperature uncertainty is limited to ±0.15 °C.
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11
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12
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Wei X, Hormel TT, Jia Y. Phase-stabilized complex-decorrelation angiography. BIOMEDICAL OPTICS EXPRESS 2021; 12:2419-2431. [PMID: 33996238 PMCID: PMC8086438 DOI: 10.1364/boe.420503] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/20/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
In this study, we developed a novel phase-stabilized complex-decorrelation (PSCD) optical coherence tomography (OCT) angiography (OCTA) method that can generate high quality OCTA images. This method has been validated using three different types of OCT systems and compared with conventional complex- and amplitude-based OCTA algorithms. Our results suggest that in combination with a pre-processing phase stabilization method, the PSCD method is insensitive to bulk motion phase shifts, less dependent on OCT reflectance than conventional complex methods and demonstrates extended dynamic range of flow signal, in contrast to other two methods.
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Affiliation(s)
- Xiang Wei
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
- Department of Biomedical Engineer, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Tristan T. Hormel
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Yali Jia
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
- Department of Biomedical Engineer, Oregon Health and Science University, Portland, Oregon 97239, USA
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13
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Imaging Motion: A Comprehensive Review of Optical Coherence Tomography Angiography. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1310:343-365. [PMID: 33834441 DOI: 10.1007/978-981-33-6064-8_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Optical coherence tomography (OCT) is a three-dimensional (3-D) optical imaging technology that provides noninvasive, micrometer resolution images of structural interiors within biological samples with an approximately 1 ~ 2 mm penetration depth. Over the last decades, advances in OCT have revolutionized biomedical imaging by demonstrating a potential of optical biopsy in preclinical and clinical settings. Recently, functional OCT imaging has shown a promise as angiography to visualize cell-perfused vasculatures in the tissue bed in vivo without requiring any exogenous contrast agents. This new technology termed OCT angiography (OCTA) possesses a unique imaging capability of delineating tissue morphology and blood or lymphatic vessels down to capillaries at real-time acquisition rates. For the past 10 years since 2007, OCTA has been proven to be a useful tool to identify disorder or dysfunction in tissue microcirculation from both experimental animal studies and clinical studies in ophthalmology and dermatology. In this section, we overview about OCTA including a basic principle of OCTA explained with simple optical physics, and its scan protocols and post-processing algorithms for acquisition of angiography. Then, potential and challenge of OCTA for clinical settings are shown with outcomes of human studies.
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Curatolo A, Birkenfeld JS, Martinez-Enriquez E, Germann JA, Muralidharan G, Palací J, Pascual D, Eliasy A, Abass A, Solarski J, Karnowski K, Wojtkowski M, Elsheikh A, Marcos S. Multi-meridian corneal imaging of air-puff induced deformation for improved detection of biomechanical abnormalities. BIOMEDICAL OPTICS EXPRESS 2020; 11:6337-6355. [PMID: 33282494 PMCID: PMC7687933 DOI: 10.1364/boe.402402] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/07/2020] [Accepted: 09/13/2020] [Indexed: 05/18/2023]
Abstract
Corneal biomechanics play a fundamental role in the genesis and progression of corneal pathologies, such as keratoconus; in corneal remodeling after corneal surgery; and in affecting the measurement accuracy of glaucoma biomarkers, such as the intraocular pressure (IOP). Air-puff induced corneal deformation imaging reveals information highlighting normal and pathological corneal response to a non-contact mechanical excitation. However, current commercial systems are limited to monitoring corneal deformation only on one corneal meridian. Here, we present a novel custom-developed swept-source optical coherence tomography (SSOCT) system, coupled with a collinear air-puff excitation, capable of acquiring dynamic corneal deformation on multiple meridians. Backed by numerical simulations of corneal deformations, we propose two different scan patterns, aided by low coil impedance galvanometric scan mirrors that permit an appropriate compromise between temporal and spatial sampling of the corneal deformation profiles. We customized the air-puff module to provide an unobstructed SSOCT field of view and different peak pressures, air-puff durations, and distances to the eye. We acquired multi-meridian corneal deformation profiles (a) in healthy human eyes in vivo, (b) in porcine eyes ex vivo under varying controlled IOP, and (c) in a keratoconus-mimicking porcine eye ex vivo. We detected deformation asymmetries, as predicted by numerical simulations, otherwise missed on a single meridian that will substantially aid in corneal biomechanics diagnostics and pathology screening.
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Affiliation(s)
- Andrea Curatolo
- Instituto de Óptica “Daza de Valdés”,
Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid,
Spain
| | - Judith S. Birkenfeld
- Instituto de Óptica “Daza de Valdés”,
Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid,
Spain
| | - Eduardo Martinez-Enriquez
- Instituto de Óptica “Daza de Valdés”,
Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid,
Spain
| | - James A. Germann
- Instituto de Óptica “Daza de Valdés”,
Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid,
Spain
| | - Geethika Muralidharan
- Instituto de Óptica “Daza de Valdés”,
Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid,
Spain
| | | | - Daniel Pascual
- Instituto de Óptica “Daza de Valdés”,
Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid,
Spain
| | - Ashkan Eliasy
- Biomechanical Engineering Group, University
of Liverpool, Liverpool, United
Kingdom
| | - Ahmed Abass
- Biomechanical Engineering Group, University
of Liverpool, Liverpool, United
Kingdom
| | - Jędrzej Solarski
- Physical Optics and Biophotonics Group,
Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw,
Poland
| | - Karol Karnowski
- Physical Optics and Biophotonics Group,
Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw,
Poland
| | - Maciej Wojtkowski
- Physical Optics and Biophotonics Group,
Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw,
Poland
| | - Ahmed Elsheikh
- Biomechanical Engineering Group, University
of Liverpool, Liverpool, United
Kingdom
- Beijing Advanced Innovation Centre for
Biomedical Engineering, Beihang University, Beijing, China
- NIHR Biomedical Research Centre for
Ophthalmology, Moorfields Eye Hospital, NHS Foundation Trust, and UCL
Institute of Ophthalmology, United
Kingdom
| | - Susana Marcos
- Instituto de Óptica “Daza de Valdés”,
Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid,
Spain
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15
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Martinez-Enriquez E, de Castro A, Mohamed A, Sravani NG, Ruggeri M, Manns F, Marcos S. Age-Related Changes to the Three-Dimensional Full Shape of the Isolated Human Crystalline Lens. Invest Ophthalmol Vis Sci 2020; 61:11. [PMID: 32293664 PMCID: PMC7401430 DOI: 10.1167/iovs.61.4.11] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Studying the full shape crystalline lens geometry is important to understand the changes undergone by the crystalline lens leading to presbyopia, cataract, or failure of emmetropization, and to aid in the design and selection of intraocular lenses and new strategies for correction. We used custom-developed three-dimensional (3-D) quantitative optical coherence tomography (OCT) to study age-related changes in the full shape of the isolated human crystalline lens. Methods A total of 103 ex vivo human isolated lenses from 87 subjects (age range, 0–56 years) were imaged using a 3-D spectral-domain OCT system. Lens models, constructed after segmentation of the surfaces and distortion correction, were used to automatically quantify central geometric parameters (lens thickness, radii of curvatures, and asphericities of anterior and posterior surfaces) and full shape parameters (lens volume, surface area, diameter, and equatorial plane position). Age-dependencies of these parameters were studied. Results Most of the measured parameters showed a biphasic behavior, statistically significantly increasing (radii of curvature, lens volume, surface area, diameter) or decreasing (asphericities, lens thickness) very fast in the first two decades of life, followed by a slow but significant increase after age 20 years (for all the parameters except for the posterior surface asphericity and the equatorial plane position, that remained constant). Conclusions Three-dimensional quantitative OCT allowed us to study the age-dependency of geometric parameters of the full isolated human crystalline lens. We found that most of the lens geometric parameters showed a biphasic behavior, changing rapidly before age 20 years and with a slower linear growth thereafter.
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16
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Xu M, Tang C, Hao F, Chen M, Lei Z. Texture preservation and speckle reduction in poor optical coherence tomography using the convolutional neural network. Med Image Anal 2020; 64:101727. [DOI: 10.1016/j.media.2020.101727] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 05/10/2020] [Accepted: 05/11/2020] [Indexed: 11/25/2022]
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Mitsukawa T, Suzuki Y, Momota Y, Suzuki S, Yamada M. Anterior Segment Biometry During Accommodation and Effects of Cycloplegics by Swept-Source Optical Coherence Tomography. Clin Ophthalmol 2020; 14:1237-1243. [PMID: 32440090 PMCID: PMC7213076 DOI: 10.2147/opth.s252474] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 04/21/2020] [Indexed: 11/23/2022] Open
Abstract
Purpose We analyzed changes in the crystalline lens during accommodation and the effects of cycloplegics by swept-source anterior-segment optical coherence tomography (AS-OCT). Materials and Methods Twenty healthy volunteers (7 males and 13 females, aged 22–34 years), with no history of eye disease except for refractive errors, were recruited. Biometric parameters, including anterior chamber depth (ACD), lens thickness (LT), and anterior and posterior curvature of the lens (ACL and PCL), were measured using AS-OCT (CASIA2). The measurements were performed with or without an accommodative demand of 5.0 diopters (D). The same tests were repeated following the topical administration of 1% cyclopentolate or a compounding agent comprising 0.5% tropicamide and 0.5% phenylephrine. Results The AS-OCT system was capable of simultaneous visualization of all optical components of the anterior segment in a single frame. ACD, LAC, and LPC decreased and LT increased significantly during 5.0 D accommodative stimulation in both eyes. Both cyclopentolate and tropicamide/phenylephrine eyedrops led to deeper ACD, thinner LT, and flatter LAC. There were no significant differences in all lens parameters despite having 5.0 D accommodative stimulation in both eyes with cycloplegia. Conclusion Our results suggest that both tropicamide/phenylephrine and cyclopentolate eyedrops have enough cycloplegic effects in young adults.
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Affiliation(s)
- Tadahiro Mitsukawa
- Department of Ophthalmology, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Yumi Suzuki
- Department of Ophthalmology, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Yosuke Momota
- Department of Ophthalmology, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Shun Suzuki
- Department of Ophthalmology, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Masakazu Yamada
- Department of Ophthalmology, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan
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18
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Pijewska E, Sylwestrzak M, Gorczynska I, Tamborski S, Pawlak MA, Szkulmowski M. Blood flow rate estimation in optic disc capillaries and vessels using Doppler optical coherence tomography with 3D fast phase unwrapping. BIOMEDICAL OPTICS EXPRESS 2020; 11:1336-1353. [PMID: 32206414 PMCID: PMC7075620 DOI: 10.1364/boe.382155] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/13/2020] [Accepted: 01/24/2020] [Indexed: 05/25/2023]
Abstract
The retinal volumetric flow rate contains useful information not only for ophthalmology but also for the diagnosis of common civilization diseases such as diabetes, Alzheimer's disease, or cerebrovascular diseases. Non-invasive optical methods for quantitative flow assessment, such as Doppler optical coherence tomography (OCT), have certain limitations. One is the phase wrapping that makes simultaneous calculations of the flow in all human retinal vessels impossible due to a very large span of flow velocities. We demonstrate that three-dimensional Doppler OCT combined with three-dimensional four Fourier transform fast phase unwrapping (3D 4FT FPU) allows for the calculation of the volumetric blood flow rate in real-time by the implementation of the algorithms in a graphics processing unit (GPU). The additive character of the flow at the furcations is proven using a microfluidic device with controlled flow rates as well as in the retinal veins bifurcations imaged in the optic disc area of five healthy volunteers. We show values of blood flow rates calculated for retinal capillaries and vessels with diameters in the range of 12-150 µm. The potential of quantitative measurement of retinal blood flow volume includes noninvasive detection of carotid artery stenosis or occlusion, measuring vascular reactivity and evaluation of vessel wall stiffness.
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Affiliation(s)
- Ewelina Pijewska
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziądzka 5, 87-100 Torun, Poland
| | - Marcin Sylwestrzak
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziądzka 5, 87-100 Torun, Poland
| | - Iwona Gorczynska
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziądzka 5, 87-100 Torun, Poland
| | - Szymon Tamborski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziądzka 5, 87-100 Torun, Poland
| | - Mikolaj A. Pawlak
- Department of Neurology and Cerebrovascular Disorders, Poznan University of Medical Sciences, Fredry 10, 61-701 Poznań, Poland
- Department of Clinical Genetics, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Maciej Szkulmowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziądzka 5, 87-100 Torun, Poland
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Corneal pulsation and biomechanics during induced ocular pulse. An ex-vivo pilot study. PLoS One 2020; 15:e0228920. [PMID: 32053692 PMCID: PMC7018024 DOI: 10.1371/journal.pone.0228920] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 01/15/2020] [Indexed: 01/16/2023] Open
Abstract
The purpose of this study was to ascertain the relationships between the amplitude of the corneal pulse (CP) signal and the parameters of corneal biomechanics during ex-vivo intraocular pressure (IOP) elevation experiments on porcine eyes with artificially induced ocular pulse cycles. Two experiments were carried out using porcine eyes. In the first one, a selected eye globe was subjected to three IOP levels (15, 30 and 45 mmHg), where changes in physical ocular pulse amplitude were controlled by infusion/withdrawal volumes (ΔV). In the second experiment, six eyes were subjected to IOP from 15 mmHg to 45 mmHg in steps of 5 mmHg with a constant ΔV, where corneal deformation parameters were measured using Corvis ST. In both experiments, at each IOP, the CP and IOP signals were acquired synchronically using a non-contact ultrasonic distance sensor and a pressure transmitter, respectively. Based on the amplitudes of the CP and IOP signals ocular pulse based corneal rigidity index (OPCRI) was calculated. Results indicate positive correlations between ΔV and the physical ocular pulse amplitude, and between ΔV and the corneal pulse amplitude (both p < 0.001). OPCRI was found to increase with elevated IOP. Furthermore, IOP statistically significantly differentiated changes in OPCRI, the amplitudes of CP and IOP signals and in most of the corneal deformation parameters (p < 0.05). The partial correlation analysis, with IOP as a control variable, revealed a significant correlation between the length of the flattened cornea during the first applanation (A1L) and the corneal pulse amplitude (p = 0.002), and between A1L and OPCRI (p = 0.003). In conclusion, this study proved that natural corneal pulsations, detected with a non-contact ultrasonic technique, reflect pressure-volume dynamics and can potentially be utilized to assess stiffness of the cornea. The proposed new rigidity index could be a simple approach to estimating corneal rigidity.
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20
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An amplitude variation Field subtraction technique for visualization of vasculature of the human eye. Biomed Signal Process Control 2019. [DOI: 10.1016/j.bspc.2019.101573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Pantalon A, Pfister M, Aranha dos Santos V, Sapeta S, Unterhuber A, Pircher N, Schmidinger G, Garhöfer G, Schmidl D, Schmetterer L, Werkmeister RM. Ultrahigh-resolution anterior segment optical coherence tomography for analysis of corneal microarchitecture during wound healing. Acta Ophthalmol 2019; 97:e761-e771. [PMID: 30762310 PMCID: PMC6767559 DOI: 10.1111/aos.14053] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 01/19/2019] [Indexed: 12/29/2022]
Abstract
PURPOSE To employ ultrahigh-resolution (UHR) optical coherence tomography (OCT) for investigation of the early wound healing process in corneal epithelium. METHODS A custom-built UHR-OCT system assessed epithelial healing in human keratoconic cornea after epi-off crosslinking (CXL) procedure and a wound healing model in rabbits with iatrogenic corneal injury. 3D OCT data sets enhanced obtaining epithelial thickness maps and evaluation of reepithelization stage. Accompanying changes in deeper corneal microarchitecture were analysed. RESULTS The mean central corneal thickness in 40 eyes with keratoconus at baseline was 482.7 ± 38.2 μm, while mean central epithelial thickness (CET) was 43.8 ± 6.4 μm. At the final visit 20 ± 5 days post-CXL procedure, CET was 35.0 ± 5.8 μm, significantly thinner after reepithelization (p < 0.001). Surgical success was assessed at the final visit through the demarcation line (DL), identified at 43.7 ± 13.5% stromal depth. In rabbits, the mean CET in 20 eyes at baseline was 35.9 ± 2.6 μm. In rabbits that revealed complete wound closure (10/20 eyes) at the last study day at 72 hr, CET was significantly thinner compared to baseline (30.4 ± 2.8 μm versus 35.4 ± 2.9 μm, p = 0.005). An intra-stromal landmark indicating early keratocyte apoptosis was measured at 30.0 ± 5.1% stromal depth. Epithelial thickness maps showed the time-course of corneal healing. CONCLUSION Ultrahigh-resolution (UHR)-OCT provided precise assessment of epithelial wound and its healing by 3D-mapping. In addition, microarchitectural changes in the cornea in early phases of epithelial healing were revealed.
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Affiliation(s)
- Anca Pantalon
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Department of OphthalmologyGr. T. Popa University of Medicine and PharmacyIasiRomania
| | - Martin Pfister
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Ocular and Dermal Effects of ThiomersMedical University of ViennaViennaAustria
| | | | - Sabina Sapeta
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Angelika Unterhuber
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Niklas Pircher
- Department of OphthalmologyMedical University of ViennaViennaAustria
| | | | - Gerhard Garhöfer
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Doreen Schmidl
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Leopold Schmetterer
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Ocular and Dermal Effects of ThiomersMedical University of ViennaViennaAustria
- Singapore Eye Research InstituteSingapore National Eye CentreSingaporeSingapore
- Ophthalmology and Visual Sciences Academic Clinical ProgramDuke‐NUS Medical SchoolSingaporeSingapore
- Ophthalmic Engineering & Innovation LaboratoryDepartment of Biomedical EngineeringFaculty of EngineeringNational University of SingaporeSingaporeSingapore
- Lee Kong Chian School of MedicineNanyang Technological UniversitySingaporeSingapore
| | - René M. Werkmeister
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Ocular and Dermal Effects of ThiomersMedical University of ViennaViennaAustria
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Observation of treated iris neovascularization by swept-source-based en-face anterior-segment optical coherence tomography angiography. Sci Rep 2019; 9:10262. [PMID: 31311970 PMCID: PMC6635404 DOI: 10.1038/s41598-019-46514-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/26/2019] [Indexed: 11/08/2022] Open
Abstract
We evaluated regression of iris neovascularization (INV) using en-face anterior-segment optical coherence tomography angiography (AS-OCTA) after anti-vascular endothelial growth factor (VEGF) therapy. Seven consecutive eyes with INV were examined before and after anti-VEGF therapy, and all AS-OCTA scans were obtained using a swept-source OCTA system with an anterior-segment lens adapter. Slit-lamp microscopy photography and anterior indocyanine green angiography also were performed. Quantitative analyses of the vascular density, vascular lacunarity, and fractal dimension on AS-OCTA images were performed. AS-OCTA visualized the INV as signals around the pupillary margin, which corresponded to the vasculature confirmed by slit-lamp microscopy. After anti-VEGF drug injection, regression of INV was observed by AS-OCTA in all eyes (100%). The vascular density decreased and vascular lacunarity increased significantly after anti-VEGF therapy. This pilot study demonstrated the ability of AS-OCTA not only to detect but also to evaluate INV. Further study is warranted to improve the algorithm for delineating the iris vasculature to decrease artifacts.
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23
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Jiménez-villar A, Mączyńska E, Cichański A, Wojtkowski M, Kałużny BJ, Grulkowski I. High-speed OCT-based ocular biometer combined with an air-puff system for determination of induced retraction-free eye dynamics. BIOMEDICAL OPTICS EXPRESS 2019; 10:3663-3680. [PMID: 31467798 PMCID: PMC6706022 DOI: 10.1364/boe.10.003663] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/16/2019] [Accepted: 06/16/2019] [Indexed: 05/20/2023]
Abstract
We demonstrate a swept source OCT-based ocular biometer integrated with an air-puff stimulus to study the reaction of the eye to mechanical stimulation in vivo. The system enables simultaneous measurement of the stimulus strength and high-speed imaging of the eye dynamics along the visual axis. We characterize the stimulus and perform optimization of the data acquisition for a proper interpretation of the results. Access to the dynamics of axial eye length allows for a determination of the eye retraction, which is used to correct the air-puff induced displacement of ocular structures. We define the parameters to quantify the reaction of the eye to the air puff and determine their reproducibility in a group of healthy subjects. We observe the corneal deformation process and axial wobbling of the crystalline lens. OCT biometer combined with the air puff is the first instrument with the potential to provide comprehensive information on the biomechanics of ocular components.
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Affiliation(s)
- Alfonso Jiménez-villar
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, ul. Grudziądzka 5, 87-100 Toruń, Poland
| | - Ewa Mączyńska
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, ul. Grudziądzka 5, 87-100 Toruń, Poland
| | - Artur Cichański
- Institute of Mechanics and Machine Design, Faculty of Mechanical Engineering, UTP University of Science and Technology, Al. Prof. S. Kaliskiego 7, 85-796 Bydgoszcz, Poland
| | - Maciej Wojtkowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, ul. Grudziądzka 5, 87-100 Toruń, Poland
- Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Bartłomiej J. Kałużny
- Division of Ophthalmology and Optometry, Department of Ophthalmology, Collegium Medicum, Nicolaus Copernicus University, ul. Ujejskiego 75, 85-168 Bydgoszcz, Poland
| | - Ireneusz Grulkowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, ul. Grudziądzka 5, 87-100 Toruń, Poland
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24
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Developments in Contact Lens Imaging: New Applications of Optical Coherence Tomography. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9132580] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Optical coherence tomography (OCT) is a high-speed and non-contact optical imaging technology widely used for noninvasive cross-sectional imaging of biological objects. Two main OCT technologies have been developed: time domain and Fourier domain technologies. The latter can be further divided into spectral domain OCT, which uses a broadband light source and a spectrometer as a detector, and swept source OCT, which employs a quickly-rotating laser source. Advances in OCT technology have made it one of the most helpful devices in ophthalmic practice. Fourier OCT has revolutionized imaging of the posterior segment of the eye, as well as of anterior structures and has enhanced the ability to diagnose and manage patients. It provides high-resolution information about the tear film, contact lens (CL), a qualitative and quantitative assessment of the anterior eye that is important in contact lens fitting, and allows possible eye surface changes while wearing contact lenses to be monitored. Potential swept source OCT technology applications include industrial processes of lens design and quality control. In this paper, we describe clinical applications and outline a variety of multifunctional uses of OCT in the field of refractive error correction with contact lenses.
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25
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Duan Y, Dong X, Zhang L, Li Y, Lei Z, Chen L, Zhou X, Zhang C, Zhang X. Ultrafast discrete swept source based on dual chirped combs for microscopic imaging. OPTICS EXPRESS 2019; 27:2621-2631. [PMID: 30732297 DOI: 10.1364/oe.27.002621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 12/27/2018] [Indexed: 06/09/2023]
Abstract
An inertial-free, ultrafast frequency comb source based on two chirped optical frequency combs (OFCs) is proposed and experimentally demonstrated. The high linearity frequency sweeping is realized by the Vernier effect between the two OFCs rather than any mechanical motion component, so that good stability and reliability are ensured and no recalibration or resampling process is required. Swept rate up to 1 MHz is realized while keeping a narrow instantaneous linewidth of 0.03 nm, thanks to the extra-cavity frequency sweeping method. The wavelength step is proportional to the swept rate (3.8 pm at 10 kHz), and can be tuned by changing the repetition rate difference between the two OFCs. This swept source is applied for high-speed wavelength encoded imaging and achieves 4.4-μm spatial resolution at a 329-kHz frame rate. Compared with the traditional time-stretch microscopy, the signal acquisition bandwidth decreased from 3.8 GHz to below 90 MHz to achieve the same spatial resolution. Furthermore, the exposure time for a specific wavelength is much longer due to the discrete sweeping feature, which is a benefit for higher sensitivity. This discrete swept source provided a promising low-cost option for high-speed biomedical imaging systems and high-accuracy spectroscopy.
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26
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Ling Y, Meiniel W, Singh-Moon R, Angelini E, Olivo-Marin JC, Hendon CP. Compressed sensing-enabled phase-sensitive swept-source optical coherence tomography. OPTICS EXPRESS 2019; 27:855-871. [PMID: 30696165 PMCID: PMC6410915 DOI: 10.1364/oe.27.000855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/30/2018] [Accepted: 12/21/2018] [Indexed: 05/21/2023]
Abstract
Here we present a novel phase-sensitive swept-source optical coherence tomography (PhS-SS-OCT) system. The simultaneously recorded calibration signal, which is commonly used in SS-OCT to stabilize the phase, is randomly sub-sampled during the acquisition, and it is later reconstructed based on the Compressed Sensing (CS) theory. We first mathematically investigated the method, and verified it through computer simulations. We then conducted a vibrational frequency test and a flow velocity measurement in phantoms to demonstrate the system's capability of handling phase-sensitive tasks. The proposed scheme shows excellent phase stability with greatly discounted data bandwidth compared with conventional procedures. We further showcased the usefulness of the system in biological samples by detecting the blood flow in ex vivo swine left marginal artery. The proposed system is compatible with most of the existing SS-OCT systems and could be a preferred solution for future high-speed phase-sensitive applications.
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Affiliation(s)
- Yuye Ling
- Department of Electrical Engineering, Columbia University, 500 W 120th St., New York, New York 10027,
USA
| | - William Meiniel
- Institut Mines-Telecom, Telecom-ParisTech, CNRS LTCI, Paris,
France
- Institut Pasteur, BioImage Analysis unit, CNRS UMR 3691, Paris,
France
| | - Rajinder Singh-Moon
- Department of Electrical Engineering, Columbia University, 500 W 120th St., New York, New York 10027,
USA
| | - Elsa Angelini
- Institut Mines-Telecom, Telecom-ParisTech, CNRS LTCI, Paris,
France
- NIHR Imperial BRC, ITMAT Data Science Group, Imperial College, London,
United Kingdom
- Department of Biomedical Engineering, Columbia University, 500 W 120th St., New York, New York 10027,
USA
| | | | - Christine P. Hendon
- Department of Electrical Engineering, Columbia University, 500 W 120th St., New York, New York 10027,
USA
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Wells WA, Thrall M, Sorokina A, Fine J, Krishnamurthy S, Haroon A, Rao B, Shevchuk MM, Wolfsen HC, Tearney GJ, Hariri LP. In Vivo and Ex Vivo Microscopy: Moving Toward the Integration of Optical Imaging Technologies Into Pathology Practice. Arch Pathol Lab Med 2018; 143:288-298. [PMID: 30525931 DOI: 10.5858/arpa.2018-0298-ra] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The traditional surgical pathology assessment requires tissue to be removed from the patient, then processed, sectioned, stained, and interpreted by a pathologist using a light microscope. Today, an array of alternate optical imaging technologies allow tissue to be viewed at high resolution, in real time, without the need for processing, fixation, freezing, or staining. Optical imaging can be done in living patients without tissue removal, termed in vivo microscopy, or also in freshly excised tissue, termed ex vivo microscopy. Both in vivo and ex vivo microscopy have tremendous potential for clinical impact in a wide variety of applications. However, in order for these technologies to enter mainstream clinical care, an expert will be required to assess and interpret the imaging data. The optical images generated from these imaging techniques are often similar to the light microscopic images that pathologists already have expertise in interpreting. Other clinical specialists do not have this same expertise in microscopy, therefore, pathologists are a logical choice to step into the developing role of microscopic imaging expert. Here, we review the emerging technologies of in vivo and ex vivo microscopy in terms of the technical aspects and potential clinical applications. We also discuss why pathologists are essential to the successful clinical adoption of such technologies and the educational resources available to help them step into this emerging role.
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Affiliation(s)
- Wendy A Wells
- From the Department of Pathology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire (Dr Wells); the Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas (Dr Thrall); the Department of Pathology, University of Illinois at Chicago, Chicago (Dr Sorokina); the Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Dr Fine); the Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston (Dr Krishnamurthy); the Department of Dermatology, Rutgers-Robert Wood Johnson Medical School, Somerset, New Jersey (Drs Haroon and Rao); the Department of Pathology, Weill Cornell Medical College, New York, New York (Dr Shevchuk); the Division of Gastroenterology & Hepatology, Mayo Clinic, Jacksonville, Florida (Dr Wolfsen); and the Wellman Center for Photomedicine (Dr Tearney) and the Department of Pathology (Drs Tearney and Hariri), Massachusetts General Hospital, Harvard Medical School, Boston
| | - Michael Thrall
- From the Department of Pathology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire (Dr Wells); the Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas (Dr Thrall); the Department of Pathology, University of Illinois at Chicago, Chicago (Dr Sorokina); the Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Dr Fine); the Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston (Dr Krishnamurthy); the Department of Dermatology, Rutgers-Robert Wood Johnson Medical School, Somerset, New Jersey (Drs Haroon and Rao); the Department of Pathology, Weill Cornell Medical College, New York, New York (Dr Shevchuk); the Division of Gastroenterology & Hepatology, Mayo Clinic, Jacksonville, Florida (Dr Wolfsen); and the Wellman Center for Photomedicine (Dr Tearney) and the Department of Pathology (Drs Tearney and Hariri), Massachusetts General Hospital, Harvard Medical School, Boston
| | - Anastasia Sorokina
- From the Department of Pathology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire (Dr Wells); the Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas (Dr Thrall); the Department of Pathology, University of Illinois at Chicago, Chicago (Dr Sorokina); the Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Dr Fine); the Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston (Dr Krishnamurthy); the Department of Dermatology, Rutgers-Robert Wood Johnson Medical School, Somerset, New Jersey (Drs Haroon and Rao); the Department of Pathology, Weill Cornell Medical College, New York, New York (Dr Shevchuk); the Division of Gastroenterology & Hepatology, Mayo Clinic, Jacksonville, Florida (Dr Wolfsen); and the Wellman Center for Photomedicine (Dr Tearney) and the Department of Pathology (Drs Tearney and Hariri), Massachusetts General Hospital, Harvard Medical School, Boston
| | - Jeffrey Fine
- From the Department of Pathology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire (Dr Wells); the Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas (Dr Thrall); the Department of Pathology, University of Illinois at Chicago, Chicago (Dr Sorokina); the Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Dr Fine); the Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston (Dr Krishnamurthy); the Department of Dermatology, Rutgers-Robert Wood Johnson Medical School, Somerset, New Jersey (Drs Haroon and Rao); the Department of Pathology, Weill Cornell Medical College, New York, New York (Dr Shevchuk); the Division of Gastroenterology & Hepatology, Mayo Clinic, Jacksonville, Florida (Dr Wolfsen); and the Wellman Center for Photomedicine (Dr Tearney) and the Department of Pathology (Drs Tearney and Hariri), Massachusetts General Hospital, Harvard Medical School, Boston
| | - Savitri Krishnamurthy
- From the Department of Pathology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire (Dr Wells); the Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas (Dr Thrall); the Department of Pathology, University of Illinois at Chicago, Chicago (Dr Sorokina); the Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Dr Fine); the Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston (Dr Krishnamurthy); the Department of Dermatology, Rutgers-Robert Wood Johnson Medical School, Somerset, New Jersey (Drs Haroon and Rao); the Department of Pathology, Weill Cornell Medical College, New York, New York (Dr Shevchuk); the Division of Gastroenterology & Hepatology, Mayo Clinic, Jacksonville, Florida (Dr Wolfsen); and the Wellman Center for Photomedicine (Dr Tearney) and the Department of Pathology (Drs Tearney and Hariri), Massachusetts General Hospital, Harvard Medical School, Boston
| | - Attiya Haroon
- From the Department of Pathology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire (Dr Wells); the Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas (Dr Thrall); the Department of Pathology, University of Illinois at Chicago, Chicago (Dr Sorokina); the Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Dr Fine); the Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston (Dr Krishnamurthy); the Department of Dermatology, Rutgers-Robert Wood Johnson Medical School, Somerset, New Jersey (Drs Haroon and Rao); the Department of Pathology, Weill Cornell Medical College, New York, New York (Dr Shevchuk); the Division of Gastroenterology & Hepatology, Mayo Clinic, Jacksonville, Florida (Dr Wolfsen); and the Wellman Center for Photomedicine (Dr Tearney) and the Department of Pathology (Drs Tearney and Hariri), Massachusetts General Hospital, Harvard Medical School, Boston
| | - Babar Rao
- From the Department of Pathology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire (Dr Wells); the Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas (Dr Thrall); the Department of Pathology, University of Illinois at Chicago, Chicago (Dr Sorokina); the Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Dr Fine); the Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston (Dr Krishnamurthy); the Department of Dermatology, Rutgers-Robert Wood Johnson Medical School, Somerset, New Jersey (Drs Haroon and Rao); the Department of Pathology, Weill Cornell Medical College, New York, New York (Dr Shevchuk); the Division of Gastroenterology & Hepatology, Mayo Clinic, Jacksonville, Florida (Dr Wolfsen); and the Wellman Center for Photomedicine (Dr Tearney) and the Department of Pathology (Drs Tearney and Hariri), Massachusetts General Hospital, Harvard Medical School, Boston
| | - Maria M Shevchuk
- From the Department of Pathology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire (Dr Wells); the Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas (Dr Thrall); the Department of Pathology, University of Illinois at Chicago, Chicago (Dr Sorokina); the Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Dr Fine); the Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston (Dr Krishnamurthy); the Department of Dermatology, Rutgers-Robert Wood Johnson Medical School, Somerset, New Jersey (Drs Haroon and Rao); the Department of Pathology, Weill Cornell Medical College, New York, New York (Dr Shevchuk); the Division of Gastroenterology & Hepatology, Mayo Clinic, Jacksonville, Florida (Dr Wolfsen); and the Wellman Center for Photomedicine (Dr Tearney) and the Department of Pathology (Drs Tearney and Hariri), Massachusetts General Hospital, Harvard Medical School, Boston
| | - Herbert C Wolfsen
- From the Department of Pathology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire (Dr Wells); the Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas (Dr Thrall); the Department of Pathology, University of Illinois at Chicago, Chicago (Dr Sorokina); the Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Dr Fine); the Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston (Dr Krishnamurthy); the Department of Dermatology, Rutgers-Robert Wood Johnson Medical School, Somerset, New Jersey (Drs Haroon and Rao); the Department of Pathology, Weill Cornell Medical College, New York, New York (Dr Shevchuk); the Division of Gastroenterology & Hepatology, Mayo Clinic, Jacksonville, Florida (Dr Wolfsen); and the Wellman Center for Photomedicine (Dr Tearney) and the Department of Pathology (Drs Tearney and Hariri), Massachusetts General Hospital, Harvard Medical School, Boston
| | - Guillermo J Tearney
- From the Department of Pathology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire (Dr Wells); the Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas (Dr Thrall); the Department of Pathology, University of Illinois at Chicago, Chicago (Dr Sorokina); the Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Dr Fine); the Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston (Dr Krishnamurthy); the Department of Dermatology, Rutgers-Robert Wood Johnson Medical School, Somerset, New Jersey (Drs Haroon and Rao); the Department of Pathology, Weill Cornell Medical College, New York, New York (Dr Shevchuk); the Division of Gastroenterology & Hepatology, Mayo Clinic, Jacksonville, Florida (Dr Wolfsen); and the Wellman Center for Photomedicine (Dr Tearney) and the Department of Pathology (Drs Tearney and Hariri), Massachusetts General Hospital, Harvard Medical School, Boston
| | - Lida P Hariri
- From the Department of Pathology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire (Dr Wells); the Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas (Dr Thrall); the Department of Pathology, University of Illinois at Chicago, Chicago (Dr Sorokina); the Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Dr Fine); the Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston (Dr Krishnamurthy); the Department of Dermatology, Rutgers-Robert Wood Johnson Medical School, Somerset, New Jersey (Drs Haroon and Rao); the Department of Pathology, Weill Cornell Medical College, New York, New York (Dr Shevchuk); the Division of Gastroenterology & Hepatology, Mayo Clinic, Jacksonville, Florida (Dr Wolfsen); and the Wellman Center for Photomedicine (Dr Tearney) and the Department of Pathology (Drs Tearney and Hariri), Massachusetts General Hospital, Harvard Medical School, Boston
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Moon S, Chen Z. Phase-stability optimization of swept-source optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2018; 9:5280-5295. [PMID: 30460128 PMCID: PMC6238911 DOI: 10.1364/boe.9.005280] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/21/2018] [Accepted: 09/25/2018] [Indexed: 05/18/2023]
Abstract
Phase-resolved imaging of swept-source optical coherence tomography (SS-OCT) is subject to phase measurement instabilities involved with the sweep variation of a frequency-swept source. In general, optically generated timing references are utilized to track the variations imposed on OCT signals. But they might not be accurately synchronized due to relative time delays. In this research, we investigated the impact of the signal delays on the timing instabilities and the consequent deviations of the measured phases. We considered two types of timing signals utilized in a popular digitizer operation mode: a sweep trigger from a fiber Bragg grating (FBG) that initiates a series of signal sampling actions clocked by an auxiliary Mach-Zehnder interferometer (MZI) signal. We found that significant instabilities were brought by the relative delays through incoherent timing corrections and timing collisions between the timing references. The best-to-worst ratio of the measured phase errors was higher than 200 while only the signal delays varied. Noise-limited phase stability was achieved with a wide dynamic range of OCT signals above 50 dB in optimized delays. This demonstrated that delay optimization is very effective in phase stabilization of SS-OCT.
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Affiliation(s)
- Sucbei Moon
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92617, USA
- Department of Physics, Kookmin University, Seoul 02707, South Korea
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92617, USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697, USA
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Relevance of Swept-Source Anterior Segment Optical Coherence Tomography for Corneal Imaging in Patients With Flap-Related Complications After LASIK. Cornea 2018; 38:93-97. [DOI: 10.1097/ico.0000000000001773] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ang M, Baskaran M, Werkmeister RM, Chua J, Schmidl D, Aranha dos Santos V, Garhöfer G, Mehta JS, Schmetterer L. Anterior segment optical coherence tomography. Prog Retin Eye Res 2018; 66:132-156. [DOI: 10.1016/j.preteyeres.2018.04.002] [Citation(s) in RCA: 216] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 02/20/2018] [Accepted: 04/04/2018] [Indexed: 02/03/2023]
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Park YM, Lee JS, Yoo JM, Park JM, Seo SW, Chung IY, Kim SJ. Comparison of anterior segment optical coherence tomography findings in acanthamoeba keratitis and herpetic epithelial keratitis. Int J Ophthalmol 2018; 11:1416-1420. [PMID: 30140650 DOI: 10.18240/ijo.2018.08.26] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 06/05/2018] [Indexed: 11/23/2022] Open
Abstract
This study is to investigate the characteristic features of Acanthamoeba keratitis (AK) that differentiating it from herpetic epithelial keratitis (HEK) using anterior segment optical coherence tomography (AS-OCT). Medical records of three eyes of each AK and herpetic keratitis who had AS-OCT examination were reviewed in this study. Slit-lamp biomicroscopy and AS-OCT was performed on the initial visit and on every follow-up visits in all patients. In all three AK cases, reflective bands in the corneal stroma that correspond to the area of radial keratoneuritis were observed. The depth of the reflective bands varied in each case. After AK treatment, slit-lamp biomicroscopy confirmed that radial keratoneuritis had resolved and AS-OCT confirmed that reflective bands in the corneal stroma had also disappeared in all patients. Unlike the AS-OCT results found in AK, highly reflective HEK lesions were observed only in the subepithelial area, not in the stroma. AS-OCT seems to be helpful analyzing the specific depth of the lesion which enables to distinguish AK from HEK.
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Affiliation(s)
- Young Min Park
- Department of Ophthalmology, School of Medicine, Gyeongsang National University, Jinju 52727, South Korea.,Gyeongsang National University Changwon Hospital, Samjeongja-ro, Seongsan-gu, Changwon-si, Gyeongsangnam-do 51472, South Korea
| | - Jong Soo Lee
- Department of Ophthalmology, School of Medicine, Pusan National University and Medical Research Institute, Pusan National University Hospital, Pusan 49241, South Korea
| | - Ji-Myong Yoo
- Department of Ophthalmology, School of Medicine, Gyeongsang National University, Jinju 52727, South Korea.,Institute of Health Science, Gyeongsang National University, Jinju 52727, South Korea
| | - Jong Moon Park
- Department of Ophthalmology, School of Medicine, Gyeongsang National University, Jinju 52727, South Korea.,Gyeongsang National University Changwon Hospital, Samjeongja-ro, Seongsan-gu, Changwon-si, Gyeongsangnam-do 51472, South Korea
| | - Seong-Wook Seo
- Department of Ophthalmology, School of Medicine, Gyeongsang National University, Jinju 52727, South Korea.,Institute of Health Science, Gyeongsang National University, Jinju 52727, South Korea
| | - In-Young Chung
- Department of Ophthalmology, School of Medicine, Gyeongsang National University, Jinju 52727, South Korea.,Institute of Health Science, Gyeongsang National University, Jinju 52727, South Korea
| | - Seong Jae Kim
- Department of Ophthalmology, School of Medicine, Gyeongsang National University, Jinju 52727, South Korea.,Institute of Health Science, Gyeongsang National University, Jinju 52727, South Korea
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Shao Y, Tao A, Jiang H, Shen M, Zhu D, Lu F, Karp CL, Ye Y, Wang J. Long scan depth optical coherence tomography on imaging accommodation: impact of enhanced axial resolution, signal-to-noise ratio and speed. EYE AND VISION (LONDON, ENGLAND) 2018; 5:16. [PMID: 30003116 PMCID: PMC6036665 DOI: 10.1186/s40662-018-0111-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 06/23/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND Spectral domain optical coherence tomography (SD-OCT) was a useful tool to study accommodation in human eye, but the maximum image depth is limited due to the decreased signal-to-noise ratio (SNR). In this study, improving optical resolutions, speeds and the SNR were achieved by custom built SD-OCT, and the evaluation of the impact of the improvement during accommodation was investigated. METHODS Three systems with different spectrometer designs, including two Charge Coupled Device (CCD) cameras and one Complementary Metal-Oxide-Semiconductor Transistor (CMOS) camera, were tested. We measured the point spread functions of a mirror at different positions to obtain the axial resolution and the SNR of three OCT systems powered with a light source with a 50 nm bandwidth, centered at a wavelength of 840 nm. Two normal subjects, aged 26 and 47, respectively, and one 75-year-old patient with an intraocular lens implanted were imaged. RESULTS The results indicated that spectrometers using cameras with 4096 camera pixels optimized the axial resolutions, due to the use of the full spectrum provided by the light source. The CCD camera system with 4096 pixels had the highest SNR and the best image quality. The system with the CMOS camera with 4096 pixels had the highest speed but had a compromised SNR compared to the CCD camera with 4096 pixels. CONCLUSIONS Using these three OCT systems, we imaged the anterior segment of the human eye before and after accommodation, which showed similar results among the different systems. The system using the CMOS camera with an ultra-long scan depth, high resolution and high scan speed exhibited the best overall performance and therefore was recommended for imaging real-time accommodation.
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Affiliation(s)
- Yilei Shao
- Bascom Palmer Eye Institute, University of Miami, Miami, FL USA
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang China
| | - Aizhu Tao
- Bascom Palmer Eye Institute, University of Miami, Miami, FL USA
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang China
| | - Hong Jiang
- Bascom Palmer Eye Institute, University of Miami, Miami, FL USA
| | - Meixiao Shen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang China
| | - Dexi Zhu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang China
| | - Fan Lu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang China
| | - Carol L. Karp
- Bascom Palmer Eye Institute, University of Miami, Miami, FL USA
| | - Yufeng Ye
- Bascom Palmer Eye Institute, University of Miami, Miami, FL USA
- Hangzhou First People’s Hospital, Hangzhou, China
| | - Jianhua Wang
- Bascom Palmer Eye Institute, University of Miami, Miami, FL USA
- Electrical and Computer Engineering, University of Miami, Miami, FL USA
- Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, 1638 NW 10th Avenue, McKnight Building - Room 202A, Miami, FL 33136 USA
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Vupparaboina KK, Dansingani KK, Goud A, Rasheed MA, Jawed F, Jana S, Richhariya A, Freund KB, Chhablani J. Quantitative shadow compensated optical coherence tomography of choroidal vasculature. Sci Rep 2018; 8:6461. [PMID: 29691426 PMCID: PMC5915389 DOI: 10.1038/s41598-018-24577-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 04/05/2018] [Indexed: 11/09/2022] Open
Abstract
Conventionally rendered optical coherence tomography (OCT) images of the posterior segment contain shadows which influence the visualization of deep structures such as the choroid. The purpose of this study was to determine whether OCT shadow compensation (SC) alters the appearance of the choroid and the apparent choroidal vascularity index (CVI), an OCT-derived estimated ratio of luminal to total choroidal volume. All scans were shadow compensated using a previously published algorithm, binarized using a novel validated algorithm and extracted binarized choroid to estimate CVI. On 27 raw swept-source OCT volume-scans of healthy subjects, the effect of SC on CVI was established both qualitatively and quantitatively. In shadow compensated scans, the choroid was visualized with greater brightness than the neurosensory retina and the masking of deep tissues by retinal blood vessels was greatly reduced. Among study subjects, significant mean difference in CVI of -0.13 was observed between raw and shadow compensated scans. Conventionally acquired OCT underestimates both choroidal reflectivity and calculated CVI. Quantitative analysis based on subjective grading demonstrated that SC increased the contrast between stromal and luminal regions and are in agreement with true tissue regions. This study is warranted to determine the effects of SC on CVI in diseased eyes.
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Affiliation(s)
- Kiran Kumar Vupparaboina
- Surjana Center for Innovation, LV Prasad Eye Institute Hyderabad, Hyderabad, Telangana, India.,Department of Electrical Engineering, Indian Institute of Technology Hyderabad, Hyderabad, Telangana, India
| | - Kunal K Dansingani
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Abhilash Goud
- Clinical Research, LV Prasad Eye Institute Hyderabad, Hyderabad, Telangana, India
| | | | - Fayez Jawed
- Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Soumya Jana
- Department of Electrical Engineering, Indian Institute of Technology Hyderabad, Hyderabad, Telangana, India
| | - Ashutosh Richhariya
- Surjana Center for Innovation, LV Prasad Eye Institute Hyderabad, Hyderabad, Telangana, India
| | - K Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, New York, USA.,LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York, USA
| | - Jay Chhablani
- Vitreo-retinal Service, LV Prasad Eye Institute Hyderabad, Hyderabad, Telangana, India.
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Montonen R, Kassamakov I, Lehmann P, Österberg K, Hæggström E. Group refractive index quantification using a Fourier domain short coherence Sagnac interferometer. OPTICS LETTERS 2018; 43:887-890. [PMID: 29444019 DOI: 10.1364/ol.43.000887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 01/12/2018] [Indexed: 06/08/2023]
Abstract
The group refractive index is important in length calibration of Fourier domain interferometers by transparent transfer standards. We demonstrate accurate group refractive index quantification using a Fourier domain short coherence Sagnac interferometer. Because of a justified linear length calibration function, the calibration constants cancel out in the evaluation of the group refractive index, which is then obtained accurately from two uncalibrated lengths. Measurements of two standard thickness coverslips revealed group indices of 1.5426±0.0042 and 1.5434±0.0046, with accuracies quoted at the 95% confidence level. This agreed with the dispersion data of the coverslip manufacturer and therefore validates our method. Our method provides a sample specific and accurate group refractive index quantification using the same Fourier domain interferometer that is to be calibrated for the length. This reduces significantly the requirements of the calibration transfer standard.
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Mazlin V, Xiao P, Dalimier E, Grieve K, Irsch K, Sahel JA, Fink M, Boccara AC. In vivo high resolution human corneal imaging using full-field optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2018; 9:557-568. [PMID: 29552393 PMCID: PMC5854058 DOI: 10.1364/boe.9.000557] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/29/2017] [Accepted: 01/04/2018] [Indexed: 05/18/2023]
Abstract
We present the first full-field optical coherence tomography (FFOCT) device capable of in vivo imaging of the human cornea. We obtained images of the epithelial structures, Bowman's layer, sub-basal nerve plexus (SNP), anterior and posterior stromal keratocytes, stromal nerves, Descemet's membrane and endothelial cells with visible nuclei. Images were acquired with a high lateral resolution of 1.7 µm and relatively large field-of-view of 1.26 mm x 1.26 mm - a combination, which, to the best of our knowledge, has not been possible with other in vivo human eye imaging methods. The latter together with a contactless operation, make FFOCT a promising candidate for becoming a new tool in ophthalmic diagnostics.
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Affiliation(s)
- Viacheslav Mazlin
- Institute Langevin, ESPCI PARIS, PSL Research University, 1 Rue Jussieu, Paris, 75005, France
| | - Peng Xiao
- Institute Langevin, ESPCI PARIS, PSL Research University, 1 Rue Jussieu, Paris, 75005, France
| | - Eugénie Dalimier
- LLTech SAS, 29 Rue du Faubourg Saint Jacques, Paris, 75014, France
| | - Kate Grieve
- Vision Institute/CIC 1423, UPMC-Sorbonne Universities, UMR_S 968/INSERM, U968/CNRS, UMR_7210, 17 Rue Moreau, Paris, 75012, France
- Quinze-Vingts National Eye Hospital, 28 Rue de Charenton, Paris, 75012, France
| | - Kristina Irsch
- Vision Institute/CIC 1423, UPMC-Sorbonne Universities, UMR_S 968/INSERM, U968/CNRS, UMR_7210, 17 Rue Moreau, Paris, 75012, France
- Quinze-Vingts National Eye Hospital, 28 Rue de Charenton, Paris, 75012, France
- Laboratory of Ophthalmic Instrument Development, The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 600 N Wolfe Street, Baltimore, MD 21287, USA
| | - José-Alain Sahel
- Vision Institute/CIC 1423, UPMC-Sorbonne Universities, UMR_S 968/INSERM, U968/CNRS, UMR_7210, 17 Rue Moreau, Paris, 75012, France
- Quinze-Vingts National Eye Hospital, 28 Rue de Charenton, Paris, 75012, France
- Department of Ophthalmology, University of Pittsburgh School of Medicine, 3550 Terrace Street, Pittsburgh, PA 15213, USA
| | - Mathias Fink
- Institute Langevin, ESPCI PARIS, PSL Research University, 1 Rue Jussieu, Paris, 75005, France
| | - A. Claude Boccara
- Institute Langevin, ESPCI PARIS, PSL Research University, 1 Rue Jussieu, Paris, 75005, France
- LLTech SAS, 29 Rue du Faubourg Saint Jacques, Paris, 75014, France
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36
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Kakue T, Endo Y, Nishitsuji T, Shimobaba T, Masuda N, Ito T. Digital holographic high-speed 3D imaging for the vibrometry of fast-occurring phenomena. Sci Rep 2017; 7:10413. [PMID: 28874744 PMCID: PMC5585211 DOI: 10.1038/s41598-017-10919-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/09/2017] [Indexed: 11/20/2022] Open
Abstract
Digital holography allows production of high-speed three-dimensional images at rates over 100,000 frames per second; however, simultaneously obtaining suitable performance and levels of accuracy using digital holography is difficult. This problem prevents high-speed three-dimensional imaging from being used for vibrometry. In this paper, we propose and test a digital holography method that can produce vibration measurements. The method is based on single-shot phase-shifting interferometry. Herein, we imaged the surface of a loudspeaker diaphragm and measured its displacement due to the vibrations produced by a frequency sweep signal. We then analyzed the frequency of the experimental data and confirmed that the frequency spectra inferred from the reconstructed images agreed well with the spectra produced by the sound recorded by a microphone. This method can be used for measuring vibrations with three-dimensional imaging for loudspeakers, microelectromechanical systems, surface acoustic wave filters, and biological tissues and organs.
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Affiliation(s)
- Takashi Kakue
- Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
| | - Yutaka Endo
- Institute of Science and Engineering, Kanazawa University, Kakuma, Kanazawa, 920-1192, Japan
| | - Takashi Nishitsuji
- Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Tomoyoshi Shimobaba
- Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Nobuyuki Masuda
- Department of Applied Electronics, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
| | - Tomoyoshi Ito
- Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
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37
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Ling Y, Yao X, Hendon CP. Highly phase-stable 200 kHz swept-source optical coherence tomography based on KTN electro-optic deflector. BIOMEDICAL OPTICS EXPRESS 2017; 8:3687-3699. [PMID: 29082103 PMCID: PMC5560834 DOI: 10.1364/boe.8.003687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/08/2017] [Accepted: 07/08/2017] [Indexed: 05/04/2023]
Abstract
The rapid advance in swept-source optical coherence tomography (SS-OCT) technology has enabled exciting new applications in elastography, angiography, and vibrometry, where both high temporal resolution and phase stability are highly sought-after. In this paper, we present a 200 kHz SS-OCT system centered at 1321 nm by using an electro-optically tuned swept source. The proposed system's performance was fully characterized, and it possesses superior phase stability (0.0012% scanning variability and <1 ns timing jitter) that is promising for many phase-sensitive imaging applications. Biological experiments were demonstrated within ex vivo human tracheobronchial ciliated epithelium where both the ciliary motion and ciliary beat frequency were successfully extracted.
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38
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Huang Y, Badar M, Nitkowski A, Weinroth A, Tansu N, Zhou C. Wide-field high-speed space-division multiplexing optical coherence tomography using an integrated photonic device. BIOMEDICAL OPTICS EXPRESS 2017; 8:3856-3867. [PMID: 28856055 PMCID: PMC5560846 DOI: 10.1364/boe.8.003856] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/21/2017] [Accepted: 07/23/2017] [Indexed: 05/15/2023]
Abstract
Space-division multiplexing optical coherence tomography (SDM-OCT) is a recently developed parallel OCT imaging method in order to achieve multi-fold speed improvement. However, the assembly of fiber optics components used in the first prototype system was labor-intensive and susceptible to errors. Here, we demonstrate a high-speed SDM-OCT system using an integrated photonic chip that can be reliably manufactured with high precisions and low per-unit cost. A three-layer cascade of 1 × 2 splitters was integrated in the photonic chip to split the incident light into 8 parallel imaging channels with ~3.7 mm optical delay in air between each channel. High-speed imaging (~1s/volume) of porcine eyes ex vivo and wide-field imaging (~18.0 × 14.3 mm2) of human fingers in vivo were demonstrated with the chip-based SDM-OCT system.
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Affiliation(s)
- Yongyang Huang
- Department of Electrical and Computer Engineering, Lehigh University, 27 Memorial Drive W, Bethlehem, PA 18015, USA
- Center for Photonics and Nanoelectronics, Lehigh University, 27 Memorial Drive W, Bethlehem, PA 18015, USA
| | - Mudabbir Badar
- Department of Electrical and Computer Engineering, Lehigh University, 27 Memorial Drive W, Bethlehem, PA 18015, USA
- Center for Photonics and Nanoelectronics, Lehigh University, 27 Memorial Drive W, Bethlehem, PA 18015, USA
| | - Arthur Nitkowski
- Tornado Spectral Systems, Inc., 555 Richmond Street West, Suite 402, Toronto, ON, M5V 3(B)1, Canada
| | - Aaron Weinroth
- Tornado Spectral Systems, Inc., 555 Richmond Street West, Suite 402, Toronto, ON, M5V 3(B)1, Canada
| | - Nelson Tansu
- Department of Electrical and Computer Engineering, Lehigh University, 27 Memorial Drive W, Bethlehem, PA 18015, USA
- Center for Photonics and Nanoelectronics, Lehigh University, 27 Memorial Drive W, Bethlehem, PA 18015, USA
| | - Chao Zhou
- Department of Electrical and Computer Engineering, Lehigh University, 27 Memorial Drive W, Bethlehem, PA 18015, USA
- Center for Photonics and Nanoelectronics, Lehigh University, 27 Memorial Drive W, Bethlehem, PA 18015, USA
- Department of Bioengineering, Lehigh University, Bethlehem, PA 18015, USA
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39
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Ling Y, Gan Y, Yao X, Hendon CP. Phase-noise analysis of swept-source optical coherence tomography systems. OPTICS LETTERS 2017; 42:1333-1336. [PMID: 28362762 PMCID: PMC6080202 DOI: 10.1364/ol.42.001333] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We propose a new model to characterize the phase noise in swept-source optical coherence tomography (SS-OCT). The new model explicitly incorporates scanning variability, timing jitter, and sample location in addition to intensity noise (shot noise). The model was analyzed and validated by using both Monte Carlo methods and experiments. We suggest that the proposed model can be used as a guideline for future SS-OCT experimental designs.
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40
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Werkmeister RM, Sapeta S, Schmidl D, Garhöfer G, Schmidinger G, Aranha dos Santos V, Aschinger GC, Baumgartner I, Pircher N, Schwarzhans F, Pantalon A, Dua H, Schmetterer L. Ultrahigh-resolution OCT imaging of the human cornea. BIOMEDICAL OPTICS EXPRESS 2017; 8:1221-1239. [PMID: 28271013 PMCID: PMC5330598 DOI: 10.1364/boe.8.001221] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 12/19/2016] [Accepted: 12/26/2016] [Indexed: 05/03/2023]
Abstract
We present imaging of corneal pathologies using optical coherence tomography (OCT) with high resolution. To this end, an ultrahigh-resolution spectral domain OCT (UHR-OCT) system based on a broad bandwidth Ti:sapphire laser is employed. With a central wavelength of 800 nm, the imaging device allows to acquire OCT data at the central, paracentral and peripheral cornea as well as the limbal region with 1.2 µm x 20 µm (axial x lateral) resolution at a rate of 140 000 A-scans/s. Structures of the anterior segment of the eye, not accessible with commercial OCT systems, are visualized. These include corneal nerves, limbal palisades of Vogt as well as several corneal pathologies. Cases such as keratoconus and Fuchs's endothelial dystrophy as well as infectious changes caused by diseases like Acanthamoeba keratitis and scarring after herpetic keratitis are presented. We also demonstrate the applicability of our system to visualize epithelial erosion and intracorneal foreign body after corneal trauma as well as chemical burns. Finally, results after Descemet's membrane endothelial keratoplasty (DMEK) are imaged. These clinical cases show the potential of UHR-OCT to help in clinical decision-making and follow-up. Our results and experience indicate that UHR-OCT of the cornea is a promising technique for the use in clinical practice, but can also help to gain novel insight in the physiology and pathophysiology of the human cornea.
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Affiliation(s)
- René M. Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- Christian Doppler Laboratory for Ocular and Dermal Effects of Thiomers, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Sabina Sapeta
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- Singapore Eye Research Institute The Academia, 20 College Road, Discovery Tower Level 6, 169856, Singapore
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Gerhard Garhöfer
- Christian Doppler Laboratory for Ocular and Dermal Effects of Thiomers, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Gerald Schmidinger
- Department of Ophthalmology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Valentin Aranha dos Santos
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Gerold C. Aschinger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Isabella Baumgartner
- Department of Ophthalmology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Niklas Pircher
- Department of Ophthalmology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Florian Schwarzhans
- Department of Ophthalmology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Spitalgasse 23, A-1090 Vienna, Austria
| | - Anca Pantalon
- Department of Ophthalmology, Gr. T. Popa University of Medicine and Pharmacy, Iasi, Sf. Spiridon University Hospital, 16 Universitatii Str, Iasi, 700115, Romania
| | - Harminder Dua
- Academic Section of Ophthalmology, Division of Clinical Neuroscience, Nottingham University Hospitals NHS Trust QMC campus, Derby Road, Nottingham, NG7 2UH, UK
| | - Leopold Schmetterer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- Christian Doppler Laboratory for Ocular and Dermal Effects of Thiomers, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- Singapore Eye Research Institute The Academia, 20 College Road, Discovery Tower Level 6, 169856, Singapore
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- Lee Kong Chian School of Medicine, Nanyang Technological University Novena Campus, 11 Mandalay Road, 308232, Singapore
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41
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Noncontact Evaluation of Corneal Grafts: Swept-Source Fourier Domain OCT Versus High-Resolution Scheimpflug Imaging. Cornea 2017; 36:434-439. [DOI: 10.1097/ico.0000000000001133] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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42
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Shin JG, Hwang HS, Eom TJ, Lee BH. In vivo three-dimensional imaging of human corneal nerves using Fourier-domain optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:10501. [PMID: 28056144 DOI: 10.1117/1.jbo.22.1.010501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 12/07/2016] [Indexed: 05/09/2023]
Abstract
We have employed Fourier-domain optical coherence tomography (FD-OCT) to achieve corneal nerve imaging, which could be useful in surgical planning and refractive surgery. Because the three-dimensional (3-D) images of the corneal nerves were acquired in vivo, unintentional movement of the subject during the measurement led to imaging artifacts. These artifacts were compensated for with a series of signal processing techniques, namely realigning A-scan images to flatten the boundary and cross-correlating adjacent B-scan images. To overcome the undesirably large signal from scattering at the corneal surface and iris, volume rendering and maximum intensity projections were performed with only the data taken in the stromal region of the cornea, which is located between 200 and 500???m from the corneal surface. The 3-D volume imaging of a 10×10??mm2 area took 9.8 s, which is slightly shorter than the normal tear breakup time. This allowed us to image the branched and threadlike corneal nerve bundles within the human eye. The experimental results show that FD-OCT systems have the potential to be useful in clinical investigations of corneal nerves and by minimizing nerve injury during clinical or surgical procedures.
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Affiliation(s)
- Jun Geun Shin
- Gwangju Institute of Science and Technology, School of Electrical Engineering and Computer Science, 123 Cheomdan-gwagiro, Gwangju 61005, Republic of Korea
| | - Ho Sik Hwang
- Hallym University, Chuncheon Sacred Heart Hospital College of Medicine, Department of Ophthalmology, 153 Gyo-dong, Chuncheon 24253, Republic of Korea
| | - Tae Joong Eom
- Gwangju Institute of Science and Technology, Advanced Photonic Research Institute, 123 Cheomdan-gwagiro, Gwangju 61005, Republic of Korea
| | - Byeong Ha Lee
- Gwangju Institute of Science and Technology, School of Electrical Engineering and Computer Science, 123 Cheomdan-gwagiro, Gwangju 61005, Republic of Korea
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43
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Szkulmowski M, Tamborski S, Wojtkowski M. Spectrometer calibration for spectroscopic Fourier domain optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2016; 7:5042-5054. [PMID: 28018723 PMCID: PMC5175550 DOI: 10.1364/boe.7.005042] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 10/15/2016] [Accepted: 10/22/2016] [Indexed: 05/19/2023]
Abstract
We propose a simple and robust procedure for Fourier domain optical coherence tomography (FdOCT) that allows to linearize the detected FdOCT spectra to wavenumber domain and, at the same time, to determine the wavelength of light for each point of detected spectrum. We show that in this approach it is possible to use any measurable physical quantity that has linear dependency on wavenumber and can be extracted from spectral fringes. The actual values of the measured quantity have no importance for the algorithm and do not need to be known at any stage of the procedure. As example we calibrate a spectral OCT spectrometer using Doppler frequency. The technique of spectral calibration can be in principle adapted to of all kind of Fourier domain OCT devices.
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44
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Ratheesh KM, Seah LK, Murukeshan VM. Spectral phase-based automatic calibration scheme for swept source-based optical coherence tomography systems. Phys Med Biol 2016; 61:7652-7663. [PMID: 27740940 DOI: 10.1088/0031-9155/61/21/7652] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The automatic calibration in Fourier-domain optical coherence tomography (FD-OCT) systems allows for high resolution imaging with precise depth ranging functionality in many complex imaging scenarios, such as microsurgery. However, the accuracy and speed of the existing automatic schemes are limited due to the functional approximations and iterative operations used in their procedures. In this paper, we present a new real-time automatic calibration scheme for swept source-based optical coherence tomography (SS-OCT) systems. The proposed automatic calibration can be performed during scanning operation and does not require an auxiliary interferometer for calibration signal generation and an additional channel for its acquisition. The proposed method makes use of the spectral component corresponding to the sample surface reflection as the calibration signal. The spectral phase function representing the non-linear sweeping characteristic of the frequency-swept laser source is determined from the calibration signal. The phase linearization with improved accuracy is achieved by normalization and rescaling of the obtained phase function. The fractional-time indices corresponding to the equidistantly spaced phase intervals are estimated directly from the resampling function and are used to resample the OCT signals. The proposed approach allows for precise calibration irrespective of the path length variation induced by the non-planar topography of the sample or galvo scanning. The conceived idea was illustrated using an in-house-developed SS-OCT system by considering the specular reflection from a mirror and other test samples. It was shown that the proposed method provides high-performance calibration in terms of axial resolution and sensitivity without increasing computational and hardware complexity.
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Affiliation(s)
- K M Ratheesh
- Center for Optical & Laser Engineering, School of Mechanical & Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
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45
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Shrestha S, Serafino MJ, Rico-Jimenez J, Park J, Chen X, Zhaorigetu S, Walton BL, Jo JA, Applegate BE. Multimodal optical coherence tomography and fluorescence lifetime imaging with interleaved excitation sources for simultaneous endogenous and exogenous fluorescence. BIOMEDICAL OPTICS EXPRESS 2016; 7:3184-3197. [PMID: 27699091 PMCID: PMC5030003 DOI: 10.1364/boe.7.003184] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 07/26/2016] [Accepted: 07/27/2016] [Indexed: 05/24/2023]
Abstract
Multimodal imaging probes a variety of tissue properties in a single image acquisition by merging complimentary imaging technologies. Exploiting synergies amongst the data, algorithms can be developed that lead to better tissue characterization than could be accomplished by the constituent imaging modalities taken alone. The combination of optical coherence tomography (OCT) with fluorescence lifetime imaging microscopy (FLIM) provides access to detailed tissue morphology and local biochemistry. The optical system described here merges 1310 nm swept-source OCT with time-domain FLIM having excitation at 355 and 532 nm. The pulses from 355 and 532 nm lasers have been interleaved to enable simultaneous acquisition of endogenous and exogenous fluorescence signals, respectively. The multimodal imaging system was validated using tissue phantoms. Nonspecific tagging with Alexa Flour 532 in a Watanbe rabbit aorta and active tagging of the LOX-1 receptor in human coronary artery, demonstrate the capacity of the system for simultaneous acquisition of OCT, endogenous FLIM, and exogenous FLIM in tissues.
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Affiliation(s)
- Sebina Shrestha
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technology Building, College Station, TX, 77843, USA
| | - Michael J. Serafino
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technology Building, College Station, TX, 77843, USA
| | - Jesus Rico-Jimenez
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technology Building, College Station, TX, 77843, USA
| | - Jesung Park
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technology Building, College Station, TX, 77843, USA
| | - Xi Chen
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technology Building, College Station, TX, 77843, USA
| | - Siqin Zhaorigetu
- Cardiovascular Experimental Imaging and Therapeutics, Texas Heart Institute, 6519 Fannin St., Houston, TX, 77030, USA
| | - Brian L. Walton
- Cardiovascular Experimental Imaging and Therapeutics, Texas Heart Institute, 6519 Fannin St., Houston, TX, 77030, USA
| | - Javier A. Jo
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technology Building, College Station, TX, 77843, USA
| | - Brian E. Applegate
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technology Building, College Station, TX, 77843, USA
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46
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Kim S, Raphael PD, Oghalai JS, Applegate BE. High-speed spectral calibration by complex FIR filter in phase-sensitive optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2016; 7:1430-44. [PMID: 27446666 PMCID: PMC4929652 DOI: 10.1364/boe.7.001430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/14/2016] [Accepted: 03/15/2016] [Indexed: 05/03/2023]
Abstract
Swept-laser sources offer a number of advantages for Phase-sensitive Optical Coherence Tomography (PhOCT). However, inter- and intra-sweep variability leads to calibration errors that adversely affect phase sensitivity. While there are several approaches to overcoming this problem, our preferred method is to simply calibrate every sweep of the laser. This approach offers high accuracy and phase stability at the expense of a substantial processing burden. In this approach, the Hilbert phase of the interferogram from a reference interferometer provides the instantaneous wavenumber of the laser, but is computationally expensive. Fortunately, the Hilbert transform may be approximated by a Finite Impulse-Response (FIR) filter. Here we explore the use of several FIR filter based Hilbert transforms for calibration, explicitly considering the impact of filter choice on phase sensitivity and OCT image quality. Our results indicate that the complex FIR filter approach is the most robust and accurate among those considered. It provides similar image quality and slightly better phase sensitivity than the traditional FFT-IFFT based Hilbert transform while consuming fewer resources in an FPGA implementation. We also explored utilizing the Hilbert magnitude of the reference interferogram to calculate an ideal window function for spectral amplitude calibration. The ideal window function is designed to carefully control sidelobes on the axial point spread function. We found that after a simple chromatic correction, calculating the window function using the complex FIR filter and the reference interferometer gave similar results to window functions calculated using a mirror sample and the FFT-IFFT Hilbert transform. Hence, the complex FIR filter can enable accurate and high-speed calibration of the magnitude and phase of spectral interferograms.
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Affiliation(s)
- Sangmin Kim
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Patrick D. Raphael
- Department of Otolaryngology, Head and Neck Surgery, Stanford University, Stanford, CA, USA
| | - John S. Oghalai
- Department of Otolaryngology, Head and Neck Surgery, Stanford University, Stanford, CA, USA
| | - Brian E. Applegate
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
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47
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High Resolution Optical Coherence Tomography for Bio-Imaging. FRONTIERS IN BIOPHOTONICS FOR TRANSLATIONAL MEDICINE 2016. [DOI: 10.1007/978-981-287-627-0_6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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48
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Hyeon MG, Kim HJ, Kim BM, Eom TJ. Spectral domain optical coherence tomography with balanced detection using single line-scan camera and optical delay line. OPTICS EXPRESS 2015; 23:23079-91. [PMID: 26368412 DOI: 10.1364/oe.23.023079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We propose a spectral domain optical coherence tomography (SD-OCT) system that uses a single line-scan detection scheme for balanced detection. Two phase-opposed spectra, generated by two optical fiber couplers, were detected by using a spectrometer with fast optical switching. A 2.69 km optical fiber was introduced to provide a proper time delay to prevent phase errors caused by the difference in measurement time between the two opposing spectra and unstable output voltages for controlling the galvano-scanner. Hence, a phase difference of π was obtained between the spectra over the sample depth without a phase error, which improved sensitivity by approximately 6 dB compared to that of conventional SD-OCT. We directly showed and compared the OCT images before and after applying the proposed balanced detection method in a phantom and in vivo sample.
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49
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Yang W, Gerke SA, Ng KW, Rao Y, Chase C, Chang-Hasnain CJ. Laser optomechanics. Sci Rep 2015; 5:13700. [PMID: 26333804 PMCID: PMC4558576 DOI: 10.1038/srep13700] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 08/03/2015] [Indexed: 11/09/2022] Open
Abstract
Cavity optomechanics explores the interaction between optical field and mechanical motion. So far, this interaction has relied on the detuning between a passive optical resonator and an external pump laser. Here, we report a new scheme with mutual coupling between a mechanical oscillator supporting the mirror of a laser and the optical field generated by the laser itself. The optically active cavity greatly enhances the light-matter energy transfer. In this work, we use an electrically-pumped vertical-cavity surface-emitting laser (VCSEL) with an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced regenerative oscillation of the laser optomechanical cavity. We observe >550 nm self-oscillation amplitude of the micromechanical oscillator, two to three orders of magnitude larger than typical, and correspondingly a 23 nm laser wavelength sweep. In addition to its immediate applications as a high-speed wavelength-swept source, this scheme also offers a new approach for integrated on-chip sensors.
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Affiliation(s)
- Weijian Yang
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA
| | - Stephen Adair Gerke
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA
| | - Kar Wei Ng
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA
| | - Yi Rao
- Bandwidth10, Inc., San Jose, CA 95132, USA
| | | | - Connie J Chang-Hasnain
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA
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50
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Del Águila-Carrasco AJ, Ferrer-Blasco T, García-Lázaro S, Esteve-Taboada JJ, Montés-Micó R. Assessment of corneal thickness and tear meniscus during contact-lens wear. Cont Lens Anterior Eye 2015; 38:185-93. [DOI: 10.1016/j.clae.2015.01.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/10/2014] [Accepted: 01/26/2015] [Indexed: 11/15/2022]
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