1
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Niederleithner M, de Sisternes L, Stino H, Sedova A, Schlegl T, Bagherinia H, Britten A, Matten P, Schmidt-Erfurth U, Pollreisz A, Drexler W, Leitgeb RA, Schmoll T. Ultra-Widefield OCT Angiography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2023; 42:1009-1020. [PMID: 36383595 DOI: 10.1109/tmi.2022.3222638] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Optical Coherence Tomography Angiography (OCTA), a functional extension of OCT, has the potential to replace most invasive fluorescein angiography (FA) exams in ophthalmology. So far, OCTA's field of view is however still lacking behind fluorescence fundus photography techniques. This is problematic, because many retinal diseases manifest at an early stage by changes of the peripheral retinal capillary network. It is therefore desirable to expand OCTA's field of view to match that of ultra-widefield fundus cameras. We present a custom developed clinical high-speed swept-source OCT (SS-OCT) system operating at an acquisition rate 8-16 times faster than today's state-of-the-art commercially available OCTA devices. Its speed allows us to capture ultra-wide fields of view of up to 90 degrees with an unprecedented sampling density and hence extraordinary resolution by merging two single shot scans with 60 degrees in diameter. To further enhance the visual appearance of the angiograms, we developed for the first time a three-dimensional deep learning based algorithm for denoising volumetric OCTA data sets. We showcase its imaging performance and clinical usability by presenting images of patients suffering from diabetic retinopathy.
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2
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Makita S, Azuma S, Mino T, Yamaguchi T, Miura M, Yasuno Y. Extending field-of-view of retinal imaging by optical coherence tomography using convolutional Lissajous and slow scan patterns. BIOMEDICAL OPTICS EXPRESS 2022; 13:5212-5230. [PMID: 36425618 PMCID: PMC9664899 DOI: 10.1364/boe.467563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/27/2022] [Accepted: 08/28/2022] [Indexed: 06/16/2023]
Abstract
Optical coherence tomography (OCT) is a high-speed non-invasive cross-sectional imaging technique. Although its imaging speed is high, three-dimensional high-spatial-sampling-density imaging of in vivo tissues with a wide field-of-view (FOV) is challenging. We employed convolved Lissajous and slow circular scanning patterns to extend the FOV of retinal OCT imaging with a 1-µm, 100-kHz-sweep-rate swept-source OCT prototype system. Displacements of sampling points due to eye movements are corrected by post-processing based on a Lissajous scan. Wide FOV three-dimensional retinal imaging with high sampling density and motion correction is achieved. Three-dimensional structures obtained using repeated imaging sessions of a healthy volunteer and two patients showed good agreement. The demonstrated technique will extend the FOV of simple point-scanning OCT, such as commercial ophthalmic OCT devices, without sacrificing sampling density.
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Affiliation(s)
- Shuichi Makita
- Computational Optics Group,
University of Tsukuba, 1–1–1 Tennodai, Tsukuba, Ibaraki 305–8573, Japan
| | - Shinnosuke Azuma
- Topcon Corporation, 75–1 Hasunumacho, Itabashi, Tokyo 174–8580, Japan
| | - Toshihiro Mino
- Topcon Corporation, 75–1 Hasunumacho, Itabashi, Tokyo 174–8580, Japan
| | - Tatsuo Yamaguchi
- Topcon Corporation, 75–1 Hasunumacho, Itabashi, Tokyo 174–8580, Japan
| | - Masahiro Miura
- Department of Ophthalmology, Tokyo Medical University Ibaraki Medical Center, 3–20–1 Chuo, Ami, Ibaraki 300–0395, Japan
| | - Yoshiaki Yasuno
- Computational Optics Group,
University of Tsukuba, 1–1–1 Tennodai, Tsukuba, Ibaraki 305–8573, Japan
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3
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Huang D, Shi Y, Li F, Wai PKA. Fourier Domain Mode Locked Laser and Its Applications. SENSORS 2022; 22:s22093145. [PMID: 35590839 PMCID: PMC9105910 DOI: 10.3390/s22093145] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/05/2022] [Accepted: 04/12/2022] [Indexed: 11/16/2022]
Abstract
The sweep rate of conventional short-cavity lasers with an intracavity-swept filter is limited by the buildup time of laser signals from spontaneous emissions. The Fourier domain mode-locked (FDML) laser was proposed to overcome the limitations of buildup time by inserting a long fiber delay in the cavity to store the whole swept signal and has attracted much interest in both theoretical and experimental studies. In this review, the theoretical models to understand the dynamics of the FDML laser and the experimental techniques to realize high speed, wide sweep range, long coherence length, high output power and highly stable swept signals in FDML lasers will be discussed. We will then discuss the applications of FDML lasers in optical coherence tomography (OCT), fiber sensing, precision measurement, microwave generation and nonlinear microscopy.
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Affiliation(s)
- Dongmei Huang
- Photonics Research Institute, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China; (D.H.); (Y.S.)
- Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen 518057, China;
| | - Yihuan Shi
- Photonics Research Institute, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China; (D.H.); (Y.S.)
- Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen 518057, China;
| | - Feng Li
- Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen 518057, China;
- Photonics Research Institute, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hong Kong, China
- Correspondence:
| | - P. K. A. Wai
- Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen 518057, China;
- Photonics Research Institute, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hong Kong, China
- Department of Physics, Hong Kong Baptist University, Hong Kong, China
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4
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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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5
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Xie R, Qiu B, Chhablani J, Zhang X. Evaluation of Choroidal Thickness Using Optical Coherent Tomography: A Review. Front Med (Lausanne) 2021; 8:783519. [PMID: 34926529 PMCID: PMC8677938 DOI: 10.3389/fmed.2021.783519] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 10/18/2021] [Indexed: 12/21/2022] Open
Abstract
The choroid is the main source of blood and nourishment supply to the eye. The dysfunction of the choroid has been implicated in various retinal and choroidal diseases. The identification and in-depth understanding of pachychoroid spectrum disorders are based on the tremendous progress of optical coherence tomography (OCT) technology in recent years, although visibility of choroid is challenging in the era of the time or spectral domain OCT. The recent rapid revolution of OCTs, such as the enhanced depth imaging OCT and the swept-source OCT, has greatly contributed to the significant improvement in the analysis of the morphology and physiology of the choroid precisely, especially to the choroid-scleral boundary and vasculature. The present review highlights the recently available evidence on the measurement methodology and the clinical significance of choroidal thickness in retinal or choroidal disorders.
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Affiliation(s)
- Rui Xie
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Retinal and Choroidal Vascular Diseases Study Group, Beijing, China
| | - Bingjie Qiu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Retinal and Choroidal Vascular Diseases Study Group, Beijing, China
| | - Jay Chhablani
- The University of Pittsburgh Medical Center Eye Center, University of Pittsburgh, Pittsburgh, PA, United States
| | - Xinyuan Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Retinal and Choroidal Vascular Diseases Study Group, Beijing, China
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6
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Leitgeb R, Placzek F, Rank E, Krainz L, Haindl R, Li Q, Liu M, Andreana M, Unterhuber A, Schmoll T, Drexler W. Enhanced medical diagnosis for dOCTors: a perspective of optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210150-PER. [PMID: 34672145 PMCID: PMC8528212 DOI: 10.1117/1.jbo.26.10.100601] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/23/2021] [Indexed: 05/17/2023]
Abstract
SIGNIFICANCE After three decades, more than 75,000 publications, tens of companies being involved in its commercialization, and a global market perspective of about USD 1.5 billion in 2023, optical coherence tomography (OCT) has become one of the fastest successfully translated imaging techniques with substantial clinical and economic impacts and acceptance. AIM Our perspective focuses on disruptive forward-looking innovations and key technologies to further boost OCT performance and therefore enable significantly enhanced medical diagnosis. APPROACH A comprehensive review of state-of-the-art accomplishments in OCT has been performed. RESULTS The most disruptive future OCT innovations include imaging resolution and speed (single-beam raster scanning versus parallelization) improvement, new implementations for dual modality or even multimodality systems, and using endogenous or exogenous contrast in these hybrid OCT systems targeting molecular and metabolic imaging. Aside from OCT angiography, no other functional or contrast enhancing OCT extension has accomplished comparable clinical and commercial impacts. Some more recently developed extensions, e.g., optical coherence elastography, dynamic contrast OCT, optoretinography, and artificial intelligence enhanced OCT are also considered with high potential for the future. In addition, OCT miniaturization for portable, compact, handheld, and/or cost-effective capsule-based OCT applications, home-OCT, and self-OCT systems based on micro-optic assemblies or photonic integrated circuits will revolutionize new applications and availability in the near future. Finally, clinical translation of OCT including medical device regulatory challenges will continue to be absolutely essential. CONCLUSIONS With its exquisite non-invasive, micrometer resolution depth sectioning capability, OCT has especially revolutionized ophthalmic diagnosis and hence is the fastest adopted imaging technology in the history of ophthalmology. Nonetheless, OCT has not been completely exploited and has substantial growth potential-in academics as well as in industry. This applies not only to the ophthalmic application field, but also especially to the original motivation of OCT to enable optical biopsy, i.e., the in situ imaging of tissue microstructure with a resolution approaching that of histology but without the need for tissue excision.
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Affiliation(s)
- Rainer Leitgeb
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Medical University of Vienna, Christian Doppler Laboratory OPTRAMED, Vienna, Austria
| | - Fabian Placzek
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Elisabet Rank
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Lisa Krainz
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Richard Haindl
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Qian Li
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Mengyang Liu
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Marco Andreana
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Angelika Unterhuber
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Tilman Schmoll
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Carl Zeiss Meditec, Inc., Dublin, California, United States
| | - Wolfgang Drexler
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Address all correspondence to Wolfgang Drexler,
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7
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Zhang Y, Liu T, Singh M, Çetintaş E, Luo Y, Rivenson Y, Larin KV, Ozcan A. Neural network-based image reconstruction in swept-source optical coherence tomography using undersampled spectral data. LIGHT, SCIENCE & APPLICATIONS 2021; 10:155. [PMID: 34326306 PMCID: PMC8322159 DOI: 10.1038/s41377-021-00594-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 07/02/2021] [Accepted: 07/06/2021] [Indexed: 05/13/2023]
Abstract
Optical coherence tomography (OCT) is a widely used non-invasive biomedical imaging modality that can rapidly provide volumetric images of samples. Here, we present a deep learning-based image reconstruction framework that can generate swept-source OCT (SS-OCT) images using undersampled spectral data, without any spatial aliasing artifacts. This neural network-based image reconstruction does not require any hardware changes to the optical setup and can be easily integrated with existing swept-source or spectral-domain OCT systems to reduce the amount of raw spectral data to be acquired. To show the efficacy of this framework, we trained and blindly tested a deep neural network using mouse embryo samples imaged by an SS-OCT system. Using 2-fold undersampled spectral data (i.e., 640 spectral points per A-line), the trained neural network can blindly reconstruct 512 A-lines in 0.59 ms using multiple graphics-processing units (GPUs), removing spatial aliasing artifacts due to spectral undersampling, also presenting a very good match to the images of the same samples, reconstructed using the full spectral OCT data (i.e., 1280 spectral points per A-line). We also successfully demonstrate that this framework can be further extended to process 3× undersampled spectral data per A-line, with some performance degradation in the reconstructed image quality compared to 2× spectral undersampling. Furthermore, an A-line-optimized undersampling method is presented by jointly optimizing the spectral sampling locations and the corresponding image reconstruction network, which improved the overall imaging performance using less spectral data points per A-line compared to 2× or 3× spectral undersampling results. This deep learning-enabled image reconstruction approach can be broadly used in various forms of spectral-domain OCT systems, helping to increase their imaging speed without sacrificing image resolution and signal-to-noise ratio.
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Affiliation(s)
- Yijie Zhang
- Electrical and Computer Engineering Department, University of California, Los Angeles, CA, 90095, USA
- Department of Bioengineering, University of California, Los Angeles, CA, 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA
| | - Tairan Liu
- Electrical and Computer Engineering Department, University of California, Los Angeles, CA, 90095, USA
- Department of Bioengineering, University of California, Los Angeles, CA, 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA
| | - Manmohan Singh
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Ege Çetintaş
- Electrical and Computer Engineering Department, University of California, Los Angeles, CA, 90095, USA
- Department of Bioengineering, University of California, Los Angeles, CA, 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA
| | - Yilin Luo
- Electrical and Computer Engineering Department, University of California, Los Angeles, CA, 90095, USA
- Department of Bioengineering, University of California, Los Angeles, CA, 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA
| | - Yair Rivenson
- Electrical and Computer Engineering Department, University of California, Los Angeles, CA, 90095, USA
- Department of Bioengineering, University of California, Los Angeles, CA, 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA
| | - Kirill V Larin
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, University of Houston, Houston, TX, 77204, USA
| | - Aydogan Ozcan
- Electrical and Computer Engineering Department, University of California, Los Angeles, CA, 90095, USA.
- Department of Bioengineering, University of California, Los Angeles, CA, 90095, USA.
- California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA.
- Department of Surgery, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA.
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8
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Schottenhamml J, Moult EM, Ploner SB, Chen S, Novais E, Husvogt L, Duker JS, Waheed NK, Fujimoto JG, Maier AK. OCT-OCTA segmentation: combining structural and blood flow information to segment Bruch's membrane. BIOMEDICAL OPTICS EXPRESS 2021; 12:84-99. [PMID: 33520378 PMCID: PMC7818963 DOI: 10.1364/boe.398222] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 10/28/2020] [Accepted: 11/11/2020] [Indexed: 05/13/2023]
Abstract
In this paper we present a fully automated graph-based segmentation algorithm that jointly uses optical coherence tomography (OCT) and OCT angiography (OCTA) data to segment Bruch's membrane (BM). This is especially valuable in cases where the spatial correlation between BM, which is usually not visible on OCT scans, and the retinal pigment epithelium (RPE), which is often used as a surrogate for segmenting BM, is distorted by pathology. We validated the performance of our proposed algorithm against manual segmentation in a total of 18 eyes from healthy controls and patients with diabetic retinopathy (DR), non-exudative age-related macular degeneration (AMD) (early/intermediate AMD, nascent geographic atrophy (nGA) and drusen-associated geographic atrophy (DAGA) and geographic atrophy (GA)), and choroidal neovascularization (CNV) with a mean absolute error of ∼0.91 pixel (∼4.1 μm). This paper suggests that OCT-OCTA segmentation may be a useful framework to complement the growing usage of OCTA in ophthalmic research and clinical communities.
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Affiliation(s)
- Julia Schottenhamml
- Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany
| | - Eric M. Moult
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Stefan B. Ploner
- Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany
| | - Siyu Chen
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Eduardo Novais
- New England Eye Center, Tufts Medical Center, Boston, MA 02116, USA
- Federal University of São Paulo, School of Medicine, São Paulo - SP, 04021-001, Brazil
| | - Lennart Husvogt
- Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jay S. Duker
- New England Eye Center, Tufts Medical Center, Boston, MA 02116, USA
| | - Nadia K. Waheed
- New England Eye Center, Tufts Medical Center, Boston, MA 02116, USA
| | - James G. Fujimoto
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Andreas K. Maier
- Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany
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9
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Athwal A, Balaratnasingam C, Yu DY, Heisler M, Sarunic MV, Ju MJ. Optimizing 3D retinal vasculature imaging in diabetic retinopathy using registration and averaging of OCT-A. BIOMEDICAL OPTICS EXPRESS 2021; 12:553-570. [PMID: 33659089 PMCID: PMC7899521 DOI: 10.1364/boe.408590] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/06/2020] [Accepted: 12/07/2020] [Indexed: 05/29/2023]
Abstract
High resolution visualization of optical coherence tomography (OCT) and OCT angiography (OCT-A) data is required to fully take advantage of the imaging modality's three-dimensional nature. However, artifacts induced by patient motion often degrade OCT-A data quality. This is especially true for patients with deteriorated focal vision, such as those with diabetic retinopathy (DR). We propose a novel methodology for software-based OCT-A motion correction achieved through serial acquisition, volumetric registration, and averaging. Motion artifacts are removed via a multi-step 3D registration process, and visibility is significantly enhanced through volumetric averaging. We demonstrate that this method permits clear 3D visualization of retinal pathologies and their surrounding features, 3D visualization of inner retinal capillary connections, as well as reliable visualization of the choriocapillaris layer.
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Affiliation(s)
- Arman Athwal
- School of Engineering Science, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Chandrakumar Balaratnasingam
- Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Australia
- Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Dao-Yi Yu
- Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Australia
- Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Morgan Heisler
- School of Engineering Science, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Marinko V. Sarunic
- School of Engineering Science, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Myeong Jin Ju
- School of Engineering Science, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
- University of British Columbia, Department of Ophthalmology and Visual Sciences, 2550 Willow Street, Vancouver, BC, V5Z 3N9, Canada
- University of British Columbia, School of Biomedical Engineering, 251–2222 Health Sciences Mall, Vancouver, BC, V6 T 1Z3, Canada
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10
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Pfeiffer T, Göb M, Draxinger W, Karpf S, Kolb JP, Huber R. Flexible A-scan rate MHz-OCT: efficient computational downscaling by coherent averaging. BIOMEDICAL OPTICS EXPRESS 2020; 11:6799-6811. [PMID: 33282524 PMCID: PMC7687947 DOI: 10.1364/boe.402477] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/18/2020] [Accepted: 09/28/2020] [Indexed: 05/29/2023]
Abstract
In order to realize adjustable A-scan rates of fast optical coherence tomography (OCT) systems, we investigate averaging of OCT image data acquired with a MHz-OCT system based on a Fourier Domain Mode Locked (FDML) laser. Increased system sensitivity and image quality can be achieved with the same system at the cost of lower imaging speed. Effectively, the A-scan rate can be reduced in software by a freely selectable factor. We demonstrate a detailed technical layout of the strategies necessary to achieve efficient coherent averaging. Since there are many new challenges specific to coherent averaging in swept source MHz-OCT, we analyze them point by point and describe the appropriate solutions. We prove that coherent averaging is possible at MHz OCT-speed without special interferometer designs or digital phase stabilization. We find, that in our system up to ∼100x coherent averaging is possible while achieving a sensitivity increase close to the ideal values. This corresponds to a speed reduction from 3.3 MHz to 33 kHz and a sensitivity gain of 20 dB. We show an imaging comparison between coherent and magnitude averaging of a human finger knuckle joint in vivo with 121 dB sensitivity for the coherent case. Further, the benefits of computational downscaling in low sensitivity MHz-OCT systems are analyzed.
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Affiliation(s)
- Tom Pfeiffer
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Optores GmbH, Gollierstr. 70, 80339 Munich, Germany
| | - Madita Göb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Wolfgang Draxinger
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Sebastian Karpf
- 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
- Medizinisches Laserzentrum Lübeck GmbH, 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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11
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Huang Z, Jiang Z, Hu Y, Zou D, Yu Y, Ren Q, Liu G, Lu Y. Retinal choroidal vessel imaging based on multi-wavelength fundus imaging with the guidance of optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2020; 11:5212-5224. [PMID: 33014609 PMCID: PMC7510854 DOI: 10.1364/boe.397750] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 08/12/2020] [Accepted: 08/17/2020] [Indexed: 06/11/2023]
Abstract
A multispectral fundus camera (MSFC), as a novel noninvasive technology, uses an extensive range of monochromatic light sources that enable the view of different sectional planes of the retinal and choroidal structures. However, MSFC imaging involves complex processes affected by various factors, and the recognized theory based on light absorption above the choroid is not sufficient. In an attempt to supplement the relevant explanations, in this study, we used optical coherence tomography (OCT), a three-dimensional tomography modality, to analyze MSFC results at the retina and choroid. The swept-source OCT system at 1060 nm wavelength with a 200 kHz A-scan rate and an MSFC with 11 bands at 470 to 845 nm are employed. A quantitative evaluation procedure is proposed to compare MSFC and OCT en face images. The comparative study shows that 1) the MSFC images with the illumination wavelength of less than 605 nm could mainly provide the retinal structure information; 2) Relative choroidal layer thickness information could be inferred from the MSFC images, especially the image acquiring under the wavelength more than 605 nm. According to the results, further investigation revealed the contribution of the perivascular tissue and the sclera scattering in the difference of vascular brightness in MSFC images.
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Affiliation(s)
- Zhiyu Huang
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Zhe Jiang
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Yicheng Hu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, No. 9 Duxue Road, Nanshan District, Shenzhen 518071, China
| | - Da Zou
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Yue Yu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Qiushi Ren
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, No. 9 Duxue Road, Nanshan District, Shenzhen 518071, China
- Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Gangjun Liu
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, No. 9 Duxue Road, Nanshan District, Shenzhen 518071, China
- Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Yanye Lu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
- Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen 518055, China
- Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-University, Erlangen-Nuremberg, Martensstrasse 3, 91058 Erlangen, Germany
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12
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Tan B, Sim R, Chua J, Wong DWK, Yao X, Garhöfer G, Schmidl D, Werkmeister RM, Schmetterer L. Approaches to quantify optical coherence tomography angiography metrics. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1205. [PMID: 33241054 PMCID: PMC7576021 DOI: 10.21037/atm-20-3246] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Optical coherence tomography (OCT) has revolutionized the field of ophthalmology in the last three decades. As an OCT extension, OCT angiography (OCTA) utilizes a fast OCT system to detect motion contrast in ocular tissue and provides a three-dimensional representation of the ocular vasculature in a non-invasive, dye-free manner. The first OCT machine equipped with OCTA function was approved by U.S. Food and Drug Administration in 2016 and now it is widely applied in clinics. To date, numerous methods have been developed to aid OCTA interpretation and quantification. In this review, we focused on the workflow of OCTA-based interpretation, beginning from the generation of the OCTA images using signal decorrelation, which we divided into intensity-based, phase-based and phasor-based methods. We further discussed methods used to address image artifacts that are commonly observed in clinical settings, to the algorithms for image enhancement, binarization, and OCTA metrics extraction. We believe a better grasp of these technical aspects of OCTA will enhance the understanding of the technology and its potential application in disease diagnosis and management. Moreover, future studies will also explore the use of ocular OCTA as a window to link ocular vasculature to the function of other organs such as the kidney and brain.
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Affiliation(s)
- Bingyao Tan
- Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore
| | - Ralene Sim
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Jacqueline Chua
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
| | - Damon W K Wong
- Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore
| | - Xinwen Yao
- Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - René M Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Leopold Schmetterer
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore.,Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore, Singapore.,Department of Ophthalmology, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.,Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
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13
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Kim TS, Joo J, Shin I, Shin P, Kang WJ, Vakoc BJ, Oh WY. 9.4 MHz A-line rate optical coherence tomography at 1300 nm using a wavelength-swept laser based on stretched-pulse active mode-locking. Sci Rep 2020; 10:9328. [PMID: 32518256 PMCID: PMC7283258 DOI: 10.1038/s41598-020-66322-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 05/08/2020] [Indexed: 01/07/2023] Open
Abstract
In optical coherence tomography (OCT), high-speed systems based at 1300 nm are among the most broadly used. Here, we present 9.4 MHz A-line rate OCT system at 1300 nm. A wavelength-swept laser based on stretched-pulse active mode locking (SPML) provides a continuous and linear-in-wavenumber sweep from 1240 nm to 1340 nm, and the OCT system using this light source provides a sensitivity of 98 dB and a single-sided 6-dB roll-off depth of 2.5 mm. We present new capabilities of the 9.4 MHz SPML-OCT system in three microscopy applications. First, we demonstrate high quality OCTA imaging at a rate of 1.3 volumes/s. Second, by utilizing its inherent phase stable characteristics, we present wide dynamic range en face Doppler OCT imaging with multiple time intervals ranging from 0.25 ms to 2.0 ms at a rate of 0.53 volumes/s. Third, we demonstrate video-rate 4D microscopic imaging of a beating Xenopus embryo heart at a rate of 30 volumes/s. This high-speed and high-performance OCT system centered at 1300 nm suggests that it can be one of the most promising high-speed OCT platforms enabling a wide range of new scientific research, industrial, and clinical applications at speeds of 10 MHz.
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Affiliation(s)
- Tae Shik Kim
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea.,KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - JongYoon Joo
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea.,KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Inho Shin
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea.,KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Paul Shin
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea.,KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Woo Jae Kang
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea.,KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Benjamin J Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | - Wang-Yuhl Oh
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea. .,KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea.
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14
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Leitgeb RA. En face optical coherence tomography: a technology review [Invited]. BIOMEDICAL OPTICS EXPRESS 2019; 10:2177-2201. [PMID: 31143489 PMCID: PMC6524600 DOI: 10.1364/boe.10.002177] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/01/2019] [Accepted: 03/05/2019] [Indexed: 05/20/2023]
Abstract
A review on the technological development of en face optical coherence tomography (OCT) and optical coherence microscopy (OCM) is provided. The terminology originally referred to time domain OCT, where the preferential scanning was performed in the en face plane. Potentially the fastest realization of en face image recording is full-field OCT, where the full en face plane is illuminated and recorded simultaneously. The term has nowadays been adopted for high-speed Fourier domain approaches, where the en face image is reconstructed from full 3D volumes either by direct slicing or through axial projection in post processing. The success of modern en face OCT lies in its immediate and easy image interpretation, which is in particular of advantage for OCM or OCT angiography. Applications of en face OCT with a focus on ophthalmology are presented. The review concludes by outlining exciting technological prospects of en face OCT based both on time as well as on Fourier domain OCT.
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Affiliation(s)
- R A Leitgeb
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
- Christian Doppler Laboratory for Innovative Optical Imaging and its Translation to Medicine, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
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15
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Chlebiej M, Gorczynska I, Rutkowski A, Kluczewski J, Grzona T, Pijewska E, Sikorski BL, Szkulmowska A, Szkulmowski M. Quality improvement of OCT angiograms with elliptical directional filtering. BIOMEDICAL OPTICS EXPRESS 2019; 10:1013-1031. [PMID: 30800529 PMCID: PMC6377873 DOI: 10.1364/boe.10.001013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/09/2019] [Accepted: 01/09/2019] [Indexed: 05/06/2023]
Abstract
We present a method of OCT angiography (OCTA) data filtering for noise suppression and improved visualization of the retinal vascular networks in en face projection images. In our approach, we use a set of filters applied in three orthogonal axes in the three-dimensional (3-D) data sets. Minimization of artifacts generated in B-scan-wise data processing is accomplished by filtering the cross-sections along the slow scanning axis. A-scans are de-noised by axial filtering. The core of the method is the application of directional filtering to the C-scans, i.e. one-pixel thick sections of the 3-D data set, perpendicular to the direction of the scanning OCT beam. The method uses a concept of structuring, directional kernels of shapes matching the geometry of the image features. We use rotating ellipses to find the most likely local orientation of the vessels and use the best matching ellipses for median filtering of the C-scans. We demonstrate our approach in the imaging of a normal human eye with laboratory-grade spectral-domain OCT setup. The "field performance" is demonstrated in imaging of diabetic retinopathy cases with a commercial OCT device. The absolute complex differences method is used for the generation of OCTA images from the data collected in the most noise-wise unfavorable OCTA scanning regime-two frame scanning.
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Affiliation(s)
- Michał Chlebiej
- Faculty of Mathematics and Computer Science, Nicolaus Copernicus University in Torun, Chopina 12/18, 87-100 Torun, Poland
- AM2M Ltd. L.P., Mickiewicza 7/17, 87-100 Torun, Poland
| | | | - Andrzej Rutkowski
- Faculty of Mathematics and Computer Science, Nicolaus Copernicus University in Torun, Chopina 12/18, 87-100 Torun, Poland
- AM2M Ltd. L.P., Mickiewicza 7/17, 87-100 Torun, Poland
| | - Jakub Kluczewski
- Faculty of Mathematics and Computer Science, Nicolaus Copernicus University in Torun, Chopina 12/18, 87-100 Torun, Poland
- AM2M Ltd. L.P., Mickiewicza 7/17, 87-100 Torun, Poland
| | - Tomasz Grzona
- Faculty of Mathematics and Computer Science, Nicolaus Copernicus University in Torun, Chopina 12/18, 87-100 Torun, Poland
- AM2M Ltd. L.P., Mickiewicza 7/17, 87-100 Torun, Poland
| | - Ewelina Pijewska
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
| | - Bartosz L. Sikorski
- Department of Ophthalmology, Nicolaus Copernicus University in Torun, 9 M. Sklodowskiej-Curie St., Bydgoszcz, Poland
- Oculomedica Eye Centre, 9 Broniewskiego St. Bydgoszcz, Poland
| | | | - Maciej Szkulmowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
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16
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Mohsen T, Kishk H. Optical coherence tomography angiography in the diagnosis of choroidal neovascular membrane. JOURNAL OF THE EGYPTIAN OPHTHALMOLOGICAL SOCIETY 2019. [DOI: 10.4103/ejos.ejos_37_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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17
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Migacz JV, Gorczynska I, Azimipour M, Jonnal R, Zawadzki RJ, Werner JS. Megahertz-rate optical coherence tomography angiography improves the contrast of the choriocapillaris and choroid in human retinal imaging. BIOMEDICAL OPTICS EXPRESS 2019; 10:50-65. [PMID: 30775082 PMCID: PMC6363198 DOI: 10.1364/boe.10.000050] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/25/2018] [Accepted: 11/27/2018] [Indexed: 05/03/2023]
Abstract
Angiographic imaging of the human eye with optical coherence tomography (OCT) is becoming an increasingly important tool in the scientific investigation and clinical management of several blinding diseases, including age-related macular degeneration and diabetic retinopathy. We have observed that OCT angiography (OCTA) of the human choriocapillaris and choroid with a 1.64 MHz A-scan rate swept-source laser yields higher contrast images as compared to a slower rate system operating at 100 kHz. This result is unexpected because signal sensitivity is reduced when acquisition rates are increased, and the incident illumination power is kept constant. The contrast of angiography images generated by acquiring multiple sequential frames and calculating the variation caused by blood flow, however, appears to be improved significantly when lower-contrast images are taken more rapidly. To demonstrate that the acquisition rate plays a role in the quality improvement, we have imaged five healthy subjects with a narrow field of view (1.2 mm) OCTA imaging system using two separate swept-source lasers of different A-line rates and compared the results quantitatively using the radially-averaged power spectrum. The average improvement in the contrast is 23.0% (+/-7.6%). Although the underlying cause of this enhancement is not explicitly determined here, we speculate that the higher-speed system suppresses the noise contribution from eye motion in subjects and operates with an inter-scan time that better discriminates the flow velocities present in the choroid and choriocapillaris. Our result informs OCT system developers on the merits of ultrahigh-speed acquisition in functional imaging applications.
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Affiliation(s)
- Justin V. Migacz
- Vison Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
| | - Iwona Gorczynska
- Vison Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
- Institute of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
| | - Mehdi Azimipour
- Vison Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
| | - Ravi Jonnal
- Vison Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
| | - Robert J. Zawadzki
- Vison Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
| | - John S. Werner
- Vison Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
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18
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Leitgeb RA, Baumann B. Multimodal Optical Medical Imaging Concepts Based on Optical Coherence Tomography. FRONTIERS IN PHYSICS 2018; 6. [PMID: 0 DOI: 10.3389/fphy.2018.00114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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19
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Yang J, Chandwani R, Zhao R, Wang Z, Jia Y, Huang D, Liu G. Polarization-multiplexed, dual-beam swept source optical coherence tomography angiography. JOURNAL OF BIOPHOTONICS 2018; 11:10.1002/jbio.201700303. [PMID: 29215796 PMCID: PMC7189903 DOI: 10.1002/jbio.201700303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 11/16/2017] [Accepted: 12/04/2017] [Indexed: 06/07/2023]
Abstract
A polarization-multiplexed, dual-beam setup is proposed to expand the field of view (FOV) for a swept source optical coherence tomography angiography (OCTA) system. This method used a Wollaston prism to split sample path light into 2 orthogonal-polarized beams. This allowed 2 beams to shine on the cornea at an angle separation of ~14°, which led to a separation of ~4.2 mm on the retina. A 3-mm glass plate was inserted into one of the beam paths to set a constant path length difference between the 2 polarized beams so the interferogram from the 2 beams are coded at different frequency bands. The resulting OCTA images from the 2 beams were coded with a depth separation of ~2 mm. A total of 5 × 5 mm2 angiograms from the 2 beams were obtained simultaneously in 4 seconds. The 2 angiograms then were montaged to get a wider FOV of ~5 × 9.2 mm2 .
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20
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Kolb JP, Pfeiffer T, Eibl M, Hakert H, Huber R. High-resolution retinal swept source optical coherence tomography with an ultra-wideband Fourier-domain mode-locked laser at MHz A-scan rates. BIOMEDICAL OPTICS EXPRESS 2018; 9:120-130. [PMID: 29359091 PMCID: PMC5772568 DOI: 10.1364/boe.9.000120] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/14/2017] [Accepted: 11/15/2017] [Indexed: 05/13/2023]
Abstract
We present a new 1060 nm Fourier domain mode locked laser (FDML laser) with a record 143 nm sweep bandwidth at 2∙ 417 kHz = 834 kHz and 120 nm at 1.67 MHz, respectively. We show that not only the bandwidth alone, but also the shape of the spectrum is critical for the resulting axial resolution, because of the specific wavelength-dependent absorption of the vitreous. The theoretical limit of our setup lies at 5.9 µm axial resolution. In vivo MHz-OCT imaging of human retina is performed and the image quality is compared to the previous results acquired with 70 nm sweep range, as well as to existing spectral domain OCT data with 2.1 µm axial resolution from literature. We identify benefits of the higher resolution, for example the improved visualization of small blood vessels in the retina besides several others.
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21
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Tremoleda JL, Alvarez K, Aden A, Donnan R, Michael-Titus AT, Tomlins PH. Heart-rate sensitive optical coherence angiography for measuring vascular changes due to posttraumatic brain injury in mice. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-6. [PMID: 29210221 DOI: 10.1117/1.jbo.22.12.121710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/09/2017] [Indexed: 06/07/2023]
Abstract
Traumatic brain injury (TBI) results in direct vascular disruption, triggering edema, and reduction in cerebral blood flow. Therefore, understanding the pathophysiology of brain microcirculation following TBI is important for the development of effective therapies. Optical coherence angiography (OCA) is a promising tool for evaluating TBI in rodent models. We develop an approach to OCA that uses the heart-rate frequency to discriminate between static tissue and vasculature. This method operates on intensity data and is therefore not phase sensitive. Furthermore, it does not require spatial overlap of voxels and thus can be applied to pre-existing datasets for which oversampling may not have been explicitly considered. Heart-rate sensitive OCA was developed for dynamic assessment of mouse microvasculature post-TBI. Results show changes occurring at 5-min intervals within the first 50 min of injury.
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Affiliation(s)
- Jordi L Tremoleda
- Queen Mary University of London, Blizard Institute, Barts and the London School of Medicine and Dent, United Kingdom
| | - Karl Alvarez
- Queen Mary University of London, School of Electrical Engineering and Computer Science, London, United Kingdom
| | - Abdirahman Aden
- Queen Mary University of London, Institute of Dentistry, Barts and the London School of Medicine and, United Kingdom
| | - Robert Donnan
- Queen Mary University of London, School of Electrical Engineering and Computer Science, London, United Kingdom
| | - Adina T Michael-Titus
- Queen Mary University of London, Blizard Institute, Barts and the London School of Medicine and Dent, United Kingdom
| | - Peter H Tomlins
- Queen Mary University of London, Institute of Dentistry, Barts and the London School of Medicine and, United Kingdom
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22
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Poddar R, Migacz JV, Schwartz DM, Werner JS, Gorczynska I. Challenges and advantages in wide-field optical coherence tomography angiography imaging of the human retinal and choroidal vasculature at 1.7-MHz A-scan rate. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-14. [PMID: 29090534 PMCID: PMC9062069 DOI: 10.1117/1.jbo.22.10.106018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 10/04/2017] [Indexed: 05/08/2023]
Abstract
We present noninvasive, three-dimensional, depth-resolved imaging of human retinal and choroidal blood circulation with a swept-source optical coherence tomography (OCT) system at 1065-nm center wavelength. Motion contrast OCT imaging was performed with the phase-variance OCT angiography method. A Fourier-domain mode-locked light source was used to enable an imaging rate of 1.7 MHz. We experimentally demonstrate the challenges and advantages of wide-field OCT angiography (OCTA). In the discussion, we consider acquisition time, scanning area, scanning density, and their influence on visualization of selected features of the retinal and choroidal vascular networks. The OCTA imaging was performed with a field of view of 16 deg (5 mm×5 mm) and 30 deg (9 mm×9 mm). Data were presented in en face projections generated from single volumes and in en face projection mosaics generated from up to 4 datasets. OCTA imaging at 1.7 MHz A-scan rate was compared with results obtained from a commercial OCTA instrument and with conventional ophthalmic diagnostic methods: fundus photography, fluorescein, and indocyanine green angiography. Comparison of images obtained from all methods is demonstrated using the same eye of a healthy volunteer. For example, imaging of retinal pathology is presented in three cases of advanced age-related macular degeneration.
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Affiliation(s)
- Raju Poddar
- University of California Davis, Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, Sacramento, California, United States
- Birla Institute of Technology, Department of Bio-Engineering, Mesra, Ranchi, Jharkhand, India
- Address all correspondence to: Raju Poddar, E-mail:
| | - Justin V. Migacz
- University of California Davis, Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, Sacramento, California, United States
| | - Daniel M. Schwartz
- University of California San Francisco, Department of Ophthalmology and Vision Science, San Francisco, California, United States
| | - John S. Werner
- University of California Davis, Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, Sacramento, California, United States
| | - Iwona Gorczynska
- University of California Davis, Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, Sacramento, California, United States
- Nicolaus Copernicus University, Institute of Physics, Toruń, Poland
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23
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Knickelbein JE, Tucker W, Kodati S, Akanda M, Sen HN. Non-invasive method of monitoring retinal vasculitis in patients with birdshot chorioretinopathy using optical coherence tomography. Br J Ophthalmol 2017; 102:815-820. [PMID: 28844053 DOI: 10.1136/bjophthalmol-2016-309837] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 07/07/2017] [Accepted: 08/14/2017] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS To investigate the utility of using montaged optical coherence tomography (OCT) thickness maps to monitor perivascular thickness as a marker of vasculitic activity in patients with large-vessel retinal vasculitis. METHODS This is a retrospective cohort study of 22 eyes of 11 patients with a history of retinal vasculitis associated with birdshot chorioretinopathy (BCR). Patients had serial spectral domain 6×6 mm cube OCT scans centred on the fovea, optic nerve and proximal branches of the superior and inferior retinal vessels. OCT thickness change maps for each respective region were analysed. Changes in perivascular thickness were confirmed by assessing vasculitic activity on fluorescein angiography (FA), when clinically indicated. RESULTS In three patients, montaged OCT scans were acquired at diagnosis and serially through initial treatment. In all three patients, montaged OCT demonstrated reduced perivascular thickening with oral prednisone treatment, which was confirmed by FA showing reduced vascular leakage in both eyes. Eight patients had serial montaged OCT scans after diagnosis and initial treatment of BCR. Four of these patients showed fluctuations in perivascular thickness during flares and treatment that were confirmed by either increased or decreased vascular leakage on FA. The other four patients remained quiet on their immunosuppressive treatment regimens, and no changes in perivascular thickness were detected. CONCLUSIONS Evaluating large-vessel perivascular thickness on OCT scans may be a useful method for non-invasively monitoring posterior pole large-vessel retinal vasculitis.
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Affiliation(s)
- Jared E Knickelbein
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - William Tucker
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Shilpa Kodati
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Marib Akanda
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - H Nida Sen
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
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24
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Khan HA, Mehmood A, Khan QA, Iqbal F, Rasheed F, Khan N, Pizzimenti JJ. A major review of optical coherence tomography angiography. EXPERT REVIEW OF OPHTHALMOLOGY 2017. [DOI: 10.1080/17469899.2017.1356229] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Hashim Ali Khan
- Ophthalmology, SEHHAT Foundation Hospital, Main KKH, Danyore, Gilgit, Pakistan
| | - Asim Mehmood
- Ophthalmology, Multan Medical & Dental College, Multan, Pakistan
| | - Qaim Ali Khan
- Ophthalmology, Poonch Medical College, AJK, Pakistan
| | - Fatima Iqbal
- School of Optometry, The University of Faisalabad, Faisalabad, Pakistan
| | - Faisal Rasheed
- Ophthalmology, Sheikh Zayd Medical College, Rahim Yar Khan, Pakistan
| | - Naeemullah Khan
- Ophthalmology, SEHHAT Foundation Hospital, Main KKH, Danyore, Gilgit, Pakistan
| | - Joseph J. Pizzimenti
- Rosenberg School of Optometry, University of the Incarte Word, San Antonio, TX, USA
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25
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de Boer JF, Leitgeb R, Wojtkowski M. Twenty-five years of optical coherence tomography: the paradigm shift in sensitivity and speed provided by Fourier domain OCT [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:3248-3280. [PMID: 28717565 PMCID: PMC5508826 DOI: 10.1364/boe.8.003248] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 04/26/2017] [Accepted: 05/22/2017] [Indexed: 05/19/2023]
Abstract
Optical coherence tomography (OCT) has become one of the most successful optical technologies implemented in medicine and clinical practice mostly due to the possibility of non-invasive and non-contact imaging by detecting back-scattered light. OCT has gone through a tremendous development over the past 25 years. From its initial inception in 1991 [Science254, 1178 (1991)] it has become an indispensable medical imaging technology in ophthalmology. Also in fields like cardiology and gastro-enterology the technology is envisioned to become a standard of care. A key contributor to the success of OCT has been the sensitivity and speed advantage offered by Fourier domain OCT. In this review paper the development of FD-OCT will be revisited, providing a single comprehensive framework to derive the sensitivity advantage of both SD- and SS-OCT. We point out the key aspects of the physics and the technology that has enabled a more than 2 orders of magnitude increase in sensitivity, and as a consequence an increase in the imaging speed without loss of image quality. This speed increase provided a paradigm shift from point sampling to comprehensive 3D in vivo imaging, whose clinical impact is still actively explored by a large number of researchers worldwide.
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Affiliation(s)
- Johannes F. de Boer
- Department of Physics and Astronomy and LaserLaB Amsterdam, VU University, De Boelelaan 1105, 1081 HV Amsterdam, Department of Ophthalmology, VU Medical Center, Amsterdam, The Netherlands
- Authors are listed in alphabetical order and contributed equally
| | - Rainer Leitgeb
- Christian Doppler Laboratory OPTRAMED, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
- Authors are listed in alphabetical order and contributed equally
| | - Maciej Wojtkowski
- Physical Optics and Biophotonics Group, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52 01-224 Warsaw, Poland
- Authors are listed in alphabetical order and contributed equally
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26
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Louzada RN, Ferrara D, Novais EA, Moult E, Cole E, Lane M, Fujimoto J, Duker JS, Baumal CR. Analysis of Scleral Feeder Vessel in Myopic Choroidal Neovascularization Using Optical Coherence Tomography Angiography. Ophthalmic Surg Lasers Imaging Retina 2017; 47:960-964. [PMID: 27759864 DOI: 10.3928/23258160-20161004-11] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 07/19/2016] [Indexed: 12/27/2022]
Abstract
To describe the appearance of a scleral-derived feeder vessel in a highly myopic eye with secondary choroidal neovascularization (CNV) as visualized on both en face high-speed swept-source (SS) optical coherence tomography angiography (OCTA) prototype, and a commercially available spectral-domain (SD) OCTA, with the corresponding en face and cross-sectional structural OCT images. In this case report, a 60-year-old white male presented with high myopia and secondary CNV in the right eye, previously treated with anti-vascular endothelial growth factor, and was imaged on both SD-OCT and SS-OCT. The neovascular complex could be visualized on both devices. Structural en face SS-OCT images demonstrated a large choroidal-scleral feeder vessel that was not visualized with SD-OCT. The authors concluded that structural en face SS-OCT better visualizes scleral feeder vessel compared to SD-OCT due to the longer wavelength (∼1,050 nm) with increased choroidal penetration and decreased sensitivity roll-off in the SS-OCT system. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:960-964.].
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27
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Kurokawa K, Liu Z, Miller DT. Adaptive optics optical coherence tomography angiography for morphometric analysis of choriocapillaris [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:1803-1822. [PMID: 28663867 PMCID: PMC5480582 DOI: 10.1364/boe.8.001803] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/14/2017] [Accepted: 02/14/2017] [Indexed: 05/18/2023]
Abstract
Histological studies have shown that morphometric changes at the microscopic level of choriocapillaris (CC) occur with aging and disease onset, and therefore may be sensitive biomarkers of outer retinal health. However, visualizing CC at this level in the living human eye is challenging because its microvascular is tightly interconnected and weakly reflecting. In this study, we address these challenges by developing and validating a method based on adaptive optics optical coherence tomography with angiography (AO-OCTA) that provides the necessary 3D resolution and image contrast to visualize and quantify these microscopic details. The complex network of anastomotic CC capillaries was successfully imaged in nine healthy subjects (26 to 68 years of age) and at seven retinal eccentricities across the macula. Using these images, four fundamental morphometric parameters of CC were characterized: retinal pigment epithelium-to-CC depth separation (17.5 ± 2.1 µm), capillary diameter (17.4 ± 2.3 µm), normalized capillary density (0.53 ± 0.08), and capillary length per unit area (50.4 ± 9.5 mm-1). AO-OCTA results were consistent with histologic studies and, unlike OCTA, showed clear delineation of CC capillaries, a requirement for measuring three of the four morphometric parameters. Success in younger and older eyes establishes a path for testing aging and disease effects in larger populations. To the best of our knowledge, this is the first quantitative morphometry of choriocapillaris at the level of individual capillaries in the living human retina.
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28
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Chen CL, Wang RK. Optical coherence tomography based angiography [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:1056-1082. [PMID: 28271003 PMCID: PMC5330554 DOI: 10.1364/boe.8.001056] [Citation(s) in RCA: 263] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/16/2017] [Indexed: 05/18/2023]
Abstract
Optical coherence tomography (OCT)-based angiography (OCTA) provides in vivo, three-dimensional vascular information by the use of flowing red blood cells as intrinsic contrast agents, enabling the visualization of functional vessel networks within microcirculatory tissue beds non-invasively, without a need of dye injection. Because of these attributes, OCTA has been rapidly translated to clinical ophthalmology within a short period of time in the development. Various OCTA algorithms have been developed to detect the functional micro-vasculatures in vivo by utilizing different components of OCT signals, including phase-signal-based OCTA, intensity-signal-based OCTA and complex-signal-based OCTA. All these algorithms have shown, in one way or another, their clinical values in revealing micro-vasculatures in biological tissues in vivo, identifying abnormal vascular networks or vessel impairment zones in retinal and skin pathologies, detecting vessel patterns and angiogenesis in eyes with age-related macular degeneration and in skin and brain with tumors, and monitoring responses to hypoxia in the brain tissue. The purpose of this paper is to provide a technical oriented overview of the OCTA developments and their potential pre-clinical and clinical applications, and to shed some lights on its future perspectives. Because of its clinical translation to ophthalmology, this review intentionally places a slightly more weight on ophthalmic OCT angiography.
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Affiliation(s)
- Chieh-Li Chen
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98195, USA
- Department of Ophthalmology, University of Washington, 325 9th Ave, Seattle, WA 98104, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98195, USA
- Department of Ophthalmology, University of Washington, 325 9th Ave, Seattle, WA 98104, USA
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29
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Klein T, Huber R. High-speed OCT light sources and systems [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:828-859. [PMID: 28270988 PMCID: PMC5330584 DOI: 10.1364/boe.8.000828] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/02/2017] [Accepted: 01/03/2017] [Indexed: 05/18/2023]
Abstract
Imaging speed is one of the most important parameters that define the performance of optical coherence tomography (OCT) systems. During the last two decades, OCT speed has increased by over three orders of magnitude. New developments in wavelength-swept lasers have repeatedly been crucial for this development. In this review, we discuss the historical evolution and current state of the art of high-speed OCT systems, with focus on wavelength swept light sources and swept source OCT systems.
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Affiliation(s)
- Thomas Klein
- Optores GmbH, Gollierstr. 70, 80339 Munich, Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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30
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Salas M, Augustin M, Ginner L, Kumar A, Baumann B, Leitgeb R, Drexler W, Prager S, Hafner J, Schmidt-Erfurth U, Pircher M. Visualization of micro-capillaries using optical coherence tomography angiography with and without adaptive optics. BIOMEDICAL OPTICS EXPRESS 2017; 8:207-222. [PMID: 28101412 PMCID: PMC5231293 DOI: 10.1364/boe.8.000207] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/10/2016] [Accepted: 12/06/2016] [Indexed: 05/18/2023]
Abstract
The purpose of this work is to investigate the benefits of adaptive optics (AO) technology for optical coherence tomography angiography (OCTA). OCTA has shown great potential in non-invasively enhancing the contrast of vessels and small capillaries. Especially the capability of the technique to visualize capillaries with a lateral extension that is below the transverse resolution of the system opens unique opportunities in diagnosing retinal vascular diseases. However, there are some limitations of this technology such as shadowing and projection artifacts caused by overlying vasculature or the inability to determine the true extension of a vessel. Thus, the evaluation of the vascular structure and density based on OCTA alone can be misleading. In this paper we compare the performance of AO-OCT, AO-OCTA and OCTA for imaging retinal vasculature. The improved transverse resolution and the reduced depth of focus of AO-OCT and AO-OCTA greatly reduce shadowing artifacts allowing for a better differentiation and segmentation of different vasculature layers of the inner retina. The comparison is done on images recorded in healthy volunteers and in diabetic patients with distinct pathologies of the retinal microvasculature.
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Affiliation(s)
- Matthias Salas
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
| | - Marco Augustin
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
| | - Laurin Ginner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
- Christian Doppler Laboratory for Innovative Optical Imaging and Its Translation to Medicine, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
| | - Abhishek Kumar
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
| | - Bernhard Baumann
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
| | - Rainer Leitgeb
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
- Christian Doppler Laboratory for Innovative Optical Imaging and Its Translation to Medicine, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
| | - Wolfgang Drexler
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
| | - Sonja Prager
- Department of Ophthalmology and Optometry, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
| | - Julia Hafner
- Department of Ophthalmology and Optometry, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
| | - Ursula Schmidt-Erfurth
- Department of Ophthalmology and Optometry, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
| | - Michael Pircher
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20 A-1090 Vienna, Austria
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31
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Li P, Cheng Y, Li P, Zhou L, Ding Z, Ni Y, Pan C. Hybrid averaging offers high-flow contrast by cost apportionment among imaging time, axial, and lateral resolution in optical coherence tomography angiography. OPTICS LETTERS 2016; 41:3944-7. [PMID: 27607943 DOI: 10.1364/ol.41.003944] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The current temporal, wavelength, angular, and spatial averaging approaches trade imaging time and resolution for multiple independent measurements that improve the flow contrast in optical coherence tomography angiography (OCTA). We find that these averaging approaches are equivalent in principle, offering almost the same flow contrast enhancement as the number of averages increases. Based on this finding, we propose a hybrid averaging strategy for contrast enhancement by cost apportionment. We demonstrate that, compared with any individual approach, the hybrid averaging is able to offer a desired flow contrast without severe degradation of imaging time and resolution. Making use of the extended range of a VCSEL-based swept-source OCT, an angular averaging approach by path length encoding is also demonstrated for flow contrast enhancement.
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32
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Chen Z, Liu M, Minneman M, Ginner L, Hoover E, Sattmann H, Bonesi M, Drexler W, Leitgeb RA. Phase-stable swept source OCT angiography in human skin using an akinetic source. BIOMEDICAL OPTICS EXPRESS 2016; 7:3032-48. [PMID: 27570695 PMCID: PMC4986811 DOI: 10.1364/boe.7.003032] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/30/2016] [Accepted: 07/07/2016] [Indexed: 05/19/2023]
Abstract
We demonstrate noninvasive structural and microvascular contrast imaging of human skin in vivo, using phase difference swept source OCT angiography (pOCTA). The pOCTA system employs an akinetic, all-semiconductor, highly phase-stable swept laser source which operates at 1340 nm central wavelength, with 37 nm bandwidth (at 0 dB region) and 200 kHz A-scan rate. The phase sensitive detection does not need any external phase stabilizing implementations, due to the outstanding high phase linearity and sweep phase repeatability within 2 mrad. We compare the performance of phase based OCTA to speckle based OCTA for visualizing human vascular networks. pOCTA shows better contrast especially for deeper vascular details as compared to speckle based OCTA. The phase stability of the akinetic source allows the OCTA system to show decent vascular contrast only with 2 B-scans. We compare the performance of using 2 versus 4 B-scans for calculating the vascular contrast. Finally, the performance of a 100 nm bandwidth akinetic laser at 1310 nm is investigated for both OCT and OCTA.
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Affiliation(s)
- Zhe Chen
- Center of Medical Physics and Biomedical Engineering, Medical University Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Mengyang Liu
- Center of Medical Physics and Biomedical Engineering, Medical University Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Michael Minneman
- Insight Photonic Solutions, Inc., 300 S. Public Rd., Lafayette CO 80026, USA
| | - Laurin Ginner
- Center of Medical Physics and Biomedical Engineering, Medical University Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
- Christian Doppler Laboratory for Innovative Optical Imaging and its Translation to Medicine, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Erich Hoover
- Insight Photonic Solutions, Inc., 300 S. Public Rd., Lafayette CO 80026, USA
| | - Harald Sattmann
- Center of Medical Physics and Biomedical Engineering, Medical University Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
- Insight Photonic Solutions, Inc., 300 S. Public Rd., Lafayette CO 80026, USA
| | - Marco Bonesi
- Center of Medical Physics and Biomedical Engineering, Medical University Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Wolfgang Drexler
- Center of Medical Physics and Biomedical Engineering, Medical University Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Rainer A. Leitgeb
- Center of Medical Physics and Biomedical Engineering, Medical University Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
- Christian Doppler Laboratory for Innovative Optical Imaging and its Translation to Medicine, Währinger Gürtel 18-20, 1090 Vienna, Austria
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33
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Liu G, Jia Y, Pechauer AD, Chandwani R, Huang D. Split-spectrum phase-gradient optical coherence tomography angiography. BIOMEDICAL OPTICS EXPRESS 2016; 7:2943-54. [PMID: 27570689 PMCID: PMC4986805 DOI: 10.1364/boe.7.002943] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/28/2016] [Accepted: 07/05/2016] [Indexed: 05/20/2023]
Abstract
A phase gradient angiography (PGA) method is proposed for optical coherence tomography (OCT). This method allows the use of phase information to map the microvasculature in tissue without the correction of bulk motion and laser trigger jitter induced phase artifacts. PGA can also be combined with the amplitude/intensity to improve the performance. Split-spectrum technique can further increase the signal to noise ratio by more than two times. In-vivo imaging of human retinal circulation is shown with a 70 kHz, 840 nm spectral domain OCT system and a 200 kHz, 1050 nm swept source OCT system. Four different OCT angiography methods are compared. The best performance was achieved with split-spectrum amplitude and phase-gradient angiography.
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34
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Makita S, Kurokawa K, Hong YJ, Miura M, Yasuno Y. Noise-immune complex correlation for optical coherence angiography based on standard and Jones matrix optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2016; 7:1525-48. [PMID: 27446673 PMCID: PMC4929659 DOI: 10.1364/boe.7.001525] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 03/24/2016] [Accepted: 03/24/2016] [Indexed: 05/18/2023]
Abstract
This paper describes a complex correlation mapping algorithm for optical coherence angiography (cmOCA). The proposed algorithm avoids the signal-to-noise ratio dependence and exhibits low noise in vasculature imaging. The complex correlation coefficient of the signals, rather than that of the measured data are estimated, and two-step averaging is introduced. Algorithms of motion artifact removal based on non perfusing tissue detection using correlation are developed. The algorithms are implemented with Jones-matrix OCT. Simultaneous imaging of pigmented tissue and vasculature is also achieved using degree of polarization uniformity imaging with cmOCA. An application of cmOCA to in vivo posterior human eyes is presented to demonstrate that high-contrast images of patients' eyes can be obtained.
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Affiliation(s)
- Shuichi Makita
- Computational Optics Group, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573,
Japan
| | - Kazuhiro Kurokawa
- Computational Optics Group, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573,
Japan
| | - Young-Joo Hong
- Computational Optics Group, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573,
Japan
| | - Masahiro Miura
- Department of Ophthalmology, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuo, Ami, Inashiki, Ibaraki 300-0395,
Japan
| | - Yoshiaki Yasuno
- Computational Optics Group, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573,
Japan
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35
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Wei W, Xu J, Baran U, Song S, Qin W, Qi X, Wang RK. Intervolume analysis to achieve four-dimensional optical microangiography for observation of dynamic blood flow. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:36005. [PMID: 26968387 PMCID: PMC5996864 DOI: 10.1117/1.jbo.21.3.036005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/11/2016] [Indexed: 05/19/2023]
Abstract
We demonstrate in vivo volumetric optical microangiography at ∼ 200 volumes/s by the use of 1.6 MHz Fourier domain mode-locking swept source optical coherence tomography and an effective 36 kHz microelectromechanical system (MEMS) scanner. We propose an intervolume analysis strategy to contrast the dynamic blood flow signal from the static tissue background. The proposed system is demonstrated by imaging cerebral blood flow in mice in vivo. For the first time, imaging speed, sensitivity, and temporal resolution become possible for a direct four-dimensional observation of microcirculations within live body parts.
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Affiliation(s)
- Wei Wei
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
| | - Jingjiang Xu
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
| | - Utku Baran
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
- University of Washington, Department of Electrical Engineering, 185 Stevens Way, Seattle, Washington 98195, United States
| | - Shaozhen Song
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
| | - Wan Qin
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
| | - Xiaoli Qi
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
- Address all correspondence to: Ruikang K. Wang, E-mail:
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36
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Gorczynska I, Migacz JV, Zawadzki RJ, Capps AG, Werner JS. Comparison of amplitude-decorrelation, speckle-variance and phase-variance OCT angiography methods for imaging the human retina and choroid. BIOMEDICAL OPTICS EXPRESS 2016; 7:911-42. [PMID: 27231598 PMCID: PMC4866465 DOI: 10.1364/boe.7.000911] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 02/03/2016] [Accepted: 02/12/2016] [Indexed: 05/18/2023]
Abstract
We compared the performance of three OCT angiography (OCTA) methods: speckle variance, amplitude decorrelation and phase variance for imaging of the human retina and choroid. Two averaging methods, split spectrum and volume averaging, were compared to assess the quality of the OCTA vascular images. All data were acquired using a swept-source OCT system at 1040 nm central wavelength, operating at 100,000 A-scans/s. We performed a quantitative comparison using a contrast-to-noise (CNR) metric to assess the capability of the three methods to visualize the choriocapillaris layer. For evaluation of the static tissue noise suppression in OCTA images we proposed to calculate CNR between the photoreceptor/RPE complex and the choriocapillaris layer. Finally, we demonstrated that implementation of intensity-based OCT imaging and OCT angiography methods allows for visualization of retinal and choroidal vascular layers known from anatomic studies in retinal preparations. OCT projection imaging of data flattened to selected retinal layers was implemented to visualize retinal and choroidal vasculature. User guided vessel tracing was applied to segment the retinal vasculature. The results were visualized in a form of a skeletonized 3D model.
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Affiliation(s)
- Iwona Gorczynska
- Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
- Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun 87-100, Poland
| | - Justin V. Migacz
- Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
| | - Robert J. Zawadzki
- Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
| | - Arlie G. Capps
- Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
- Physics Division, Lawrence Livermore National Laboratory Livermore, CA 94550, USA
| | - John S. Werner
- Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
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37
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Choi W, Moult EM, Waheed NK, Adhi M, Lee B, Lu CD, de Carlo TE, Jayaraman V, Rosenfeld PJ, Duker JS, Fujimoto JG. Ultrahigh-Speed, Swept-Source Optical Coherence Tomography Angiography in Nonexudative Age-Related Macular Degeneration with Geographic Atrophy. Ophthalmology 2015; 122:2532-44. [PMID: 26481819 PMCID: PMC4658257 DOI: 10.1016/j.ophtha.2015.08.029] [Citation(s) in RCA: 211] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 08/13/2015] [Accepted: 08/24/2015] [Indexed: 10/22/2022] Open
Abstract
PURPOSE To investigate ultrahigh-speed, swept-source optical coherence tomography (SSOCT) angiography for visualizing vascular changes in eyes with nonexudative age-related macular degeneration (AMD) with geographic atrophy (GA). DESIGN Observational, prospective, cross-sectional study. PARTICIPANTS A total of 63 eyes from 32 normal subjects and 12 eyes from 7 patients with nonexudative AMD with GA. METHODS A 1050-nm, 400-kHz A-scan rate SSOCT system was used to perform volumetric optical coherence tomography angiography (OCTA) of the retinal and choriocapillaris (CC) vasculatures in normal subjects and patients with nonexudative AMD with GA. Optical coherence tomography angiography using variable interscan time analysis (VISTA) was performed to assess CC alteration and differentiate varying degrees of CC flow impairment. MAIN OUTCOME MEASURES Qualitative comparison of retinal and CC vasculatures in normal subjects versus those in patients with a clinical diagnosis of nonexudative AMD with GA. RESULTS In all 12 eyes with GA, OCTA showed pronounced CC flow impairment within the region of GA. In 10 of the 12 eyes with GA, OCTA with VISTA showed milder CC flow impairment extending beyond the margin of GA. Of the 5 eyes exhibiting foveal-sparing GA, OCTA showed CC flow within the region of foveal sparing in 4 of the eyes. CONCLUSIONS The ability of ultrahigh-speed, swept-source OCTA to noninvasively visualize alterations in the retinal and CC vasculatures makes it a promising tool for assessing nonexudative AMD with GA. Optical coherence tomography angiography using VISTA can distinguish varying degrees of CC alteration and flow impairment and may be useful for elucidating disease pathogenesis, progression, and response to therapy.
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Affiliation(s)
- WooJhon Choi
- Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Eric M Moult
- Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts; Division of Health Sciences and Technology, Harvard-Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Nadia K Waheed
- New England Eye Center, Tufts University Medical Center, Boston, Massachusetts
| | - Mehreen Adhi
- New England Eye Center, Tufts University Medical Center, Boston, Massachusetts
| | - ByungKun Lee
- Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Chen D Lu
- Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Talisa E de Carlo
- New England Eye Center, Tufts University Medical Center, Boston, Massachusetts
| | | | - Philip J Rosenfeld
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Jay S Duker
- New England Eye Center, Tufts University Medical Center, Boston, Massachusetts
| | - James G Fujimoto
- Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts.
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Amarakoon S, de Jong JH, Braaf B, Yzer S, Missotten T, van Velthoven MEJ, de Boer JF. Phase-Resolved Doppler Optical Coherence Tomographic Features in Retinal Angiomatous Proliferation. Am J Ophthalmol 2015. [PMID: 26210860 DOI: 10.1016/j.ajo.2015.07.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE To study patients diagnosed with retinal angiomatous proliferation (RAP) based on conventional imaging techniques with phase-resolved Doppler optical coherence tomography (OCT) to detect and localize blood flow in RAP lesions; and to compare these findings to conventional imaging, which are mostly invasive and give limited information concerning intra- and transretinal blood flow. DESIGN Single-center, consecutive observational case series. METHODS Twelve treatment-naïve patients diagnosed with RAP based on fundus examination, fluorescein angiography, and indocyanine green angiography were included. Median age was 79 years (range 65-90). Patients were imaged with an experimental 1040 nm swept-source phase-resolved Doppler OCT instrument. Abnormal flow was defined as intraretinal neovascularization or retinal choroidal anastomosis. RESULTS In 11 patients adequate phase-resolved Doppler OCT images were obtained showing abnormal blood flow in the RAP lesion. In 4 patients a retinal choroidal anastomosis was found, 3 patients showed intraretinal neovascularization connected with a pigment epithelial detachment, 2 patients showed only intraretinal neovascularization, and in 2 patients flow was limited to the subretinal or sub-retinal pigment epithelial space. CONCLUSIONS Phase-resolved Doppler OCT is able to detect and localize abnormal blood flow within RAP lesions. Blood flow was mostly confined to the intraretinal structures with or without a connecting pigment epithelial detachment; in one-third of patients a retinal choroidal anastomosis was detected. The potential of angiography with phase-resolved Doppler OCT to accurately distinguish between normal and pathologic blood flow in addition to structural OCT data without invasive procedures will help to further elucidate both retinal and choroidal vascular pathologies like RAP.
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Affiliation(s)
- Sankha Amarakoon
- Rotterdam Ophthalmic Institute, Rotterdam, Netherlands; Medical Retina Service, Rotterdam Eye Hospital, Rotterdam, Netherlands
| | - Jan H de Jong
- Rotterdam Ophthalmic Institute, Rotterdam, Netherlands
| | - Boy Braaf
- Rotterdam Ophthalmic Institute, Rotterdam, Netherlands
| | - Suzanne Yzer
- Medical Retina Service, Rotterdam Eye Hospital, Rotterdam, Netherlands
| | - Tom Missotten
- Rotterdam Ophthalmic Institute, Rotterdam, Netherlands; Medical Retina Service, Rotterdam Eye Hospital, Rotterdam, Netherlands
| | - Mirjam E J van Velthoven
- Rotterdam Ophthalmic Institute, Rotterdam, Netherlands; Medical Retina Service, Rotterdam Eye Hospital, Rotterdam, Netherlands.
| | - Johannes F de Boer
- Rotterdam Ophthalmic Institute, Rotterdam, Netherlands; Institute for Lasers, Life and Biophotonics Amsterdam, Department of Physics and Astronomy, VU University, Amsterdam, Netherlands
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Zhang A, Zhang Q, Chen CL, Wang RK. Methods and algorithms for optical coherence tomography-based angiography: a review and comparison. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:100901. [PMID: 26473588 PMCID: PMC4881033 DOI: 10.1117/1.jbo.20.10.100901] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/28/2015] [Indexed: 05/18/2023]
Abstract
Optical coherence tomography (OCT)-based angiography is increasingly becoming a clinically useful and important imaging technique due to its ability to provide volumetric microvascular networks innervating tissue beds in vivo without a need for exogenous contrast agent. Numerous OCT angiography algorithms have recently been proposed for the purpose of contrasting microvascular networks. A general literature review is provided on the recent progress of OCT angiography methods and algorithms. The basic physics and mathematics behind each method together with its contrast mechanism are described. Potential directions for future technical development of OCT based angiography is then briefly discussed. Finally, by the use of clinical data captured from normal and pathological subjects, the imaging performance of vascular networks delivered by the most recently reported algorithms is evaluated and compared, including optical microangiography, speckle variance,phase variance, split-spectrum amplitude decorrelation angiography, and correlation mapping. It is found that the method that utilizes complex OCT signal to contrast retinal blood flow delivers the best performance among all the algorithms in terms of image contrast and vessel connectivity. The purpose of this review is to help readers understand and select appropriate OCT angiography algorithm for use in specific applications.
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Affiliation(s)
- Anqi Zhang
- University of Washington, Department of Bioengineering, Seattle, Washington 98195, United States
| | - Qinqin Zhang
- University of Washington, Department of Bioengineering, Seattle, Washington 98195, United States
| | - Chieh-Li Chen
- University of Washington, Department of Bioengineering, Seattle, Washington 98195, United States
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, Seattle, Washington 98195, United States
- Address all correspondence to: Ruikang K. Wang, E-mail:
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40
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Ruminski D, Sikorski BL, Bukowska D, Szkulmowski M, Krawiec K, Malukiewicz G, Bieganowski L, Wojtkowski M. OCT angiography by absolute intensity difference applied to normal and diseased human retinas. BIOMEDICAL OPTICS EXPRESS 2015; 6:2738-54. [PMID: 26309740 PMCID: PMC4541504 DOI: 10.1364/boe.6.002738] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 06/30/2015] [Accepted: 06/30/2015] [Indexed: 05/22/2023]
Abstract
We compare four optical coherence tomography techniques for noninvasive visualization of microcapillary network in the human retina and murine cortex. We perform phantom studies to investigate contrast-to-noise ratio for angiographic images obtained with each of the algorithm. We show that the computationally simplest absolute intensity difference angiographic OCT algorithm that bases only on two cross-sectional intensity images may be successfully used in clinical study of healthy eyes and eyes with diabetic maculopathy and branch retinal vein occlusion.
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Affiliation(s)
- Daniel Ruminski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
- both authors contributed equally
| | - Bartosz L. Sikorski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
- Department of Ophthalmology, Nicolaus Copernicus University, 9 M. Sklodowskiej-Curie St., 85-094 Bydgoszcz, Poland
- both authors contributed equally
| | - Danuta Bukowska
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
| | - Maciej Szkulmowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
| | - Krzysztof Krawiec
- Laboratory of Intelligent Decision Support Systems, Poznan University of Technology, Piotrowo 2, 60-965 Poznań, Poland
| | - Grazyna Malukiewicz
- Department of Ophthalmology, Nicolaus Copernicus University, 9 M. Sklodowskiej-Curie St., 85-094 Bydgoszcz, Poland
| | - Lech Bieganowski
- Collegium Medicum, Nicolaus Copernicus University in Torun, Jagiellońska 13-15, 85-067 Bydgoszcz, Poland
| | - Maciej Wojtkowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
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Miura M, Muramatsu D, Hong YJ, Yasuno Y, Itami A, Iwasaki T, Goto H. Noninvasive vascular imaging of ruptured retinal arterial macroaneurysms by Doppler optical coherence tomography. BMC Ophthalmol 2015. [PMID: 26198253 PMCID: PMC4510894 DOI: 10.1186/s12886-015-0077-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background To describe Doppler optical coherence tomography (OCT) imaging of ruptured retinal arterial macroaneurysms (RAMs). Methods Four eyes of four patients with ruptured RAMs were prospectively studied. Vascular imaging was obtained using swept-source Doppler OCT, and compared with indocyanine green angiography images. Results En face projection of Doppler OCT images clearly showed RAMs at the corresponding locations of lesions in the indocyanine green angiography images. In Doppler OCT images, RAMs were located in the inner retina in three eyes and in the medium layer of the retina in one eye. In one eye, detection of RAMs by standard OCT was difficult because of the presence of inner retinal hemorrhage. In one eye, disappearance of blood flow after direct laser photocoagulation could be confirmed by Doppler OCT images. Conclusions Doppler OCT imaging may potentially function as a noninvasive complementary procedure with indocyanine green angiography.
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Affiliation(s)
- Masahiro Miura
- Department of Ophthalmology, Tokyo Medical University, Ibaraki Medical Center, 3-20-1 Chuo, Ami, Inashiki, Ibaraki, 3000395, Japan. .,Department of Ophthalmology, Tokyo Medical University, 6-7-1 Nishi-Shinjuku, Shinjuku, Tokyo, 1600023, Japan.
| | - Daisuke Muramatsu
- Department of Ophthalmology, Tokyo Medical University, Ibaraki Medical Center, 3-20-1 Chuo, Ami, Inashiki, Ibaraki, 3000395, Japan. .,Department of Ophthalmology, Tokyo Medical University, 6-7-1 Nishi-Shinjuku, Shinjuku, Tokyo, 1600023, Japan.
| | - Young-Joo Hong
- Computational Optics Group, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 3058571, Japan.
| | - Yoshiaki Yasuno
- Computational Optics Group, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 3058571, Japan.
| | - Ayako Itami
- Department of Ophthalmology, Tokyo Medical University, Ibaraki Medical Center, 3-20-1 Chuo, Ami, Inashiki, Ibaraki, 3000395, Japan. .,Department of Ophthalmology, Tokyo Medical University, 6-7-1 Nishi-Shinjuku, Shinjuku, Tokyo, 1600023, Japan.
| | - Takuya Iwasaki
- Department of Ophthalmology, Tokyo Medical University, Ibaraki Medical Center, 3-20-1 Chuo, Ami, Inashiki, Ibaraki, 3000395, Japan. .,Department of Ophthalmology, Tokyo Medical University, 6-7-1 Nishi-Shinjuku, Shinjuku, Tokyo, 1600023, Japan.
| | - Hiroshi Goto
- Department of Ophthalmology, Tokyo Medical University, 6-7-1 Nishi-Shinjuku, Shinjuku, Tokyo, 1600023, Japan.
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Jirauschek C, Huber R. Wavelength shifting of intra-cavity photons: Adiabatic wavelength tuning in rapidly wavelength-swept lasers. BIOMEDICAL OPTICS EXPRESS 2015; 6:2448-2465. [PMID: 26203373 PMCID: PMC4505701 DOI: 10.1364/boe.6.002448] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 05/10/2015] [Indexed: 05/18/2023]
Abstract
We analyze the physics behind the newest generation of rapidly wavelength tunable sources for optical coherence tomography (OCT), retaining a single longitudinal cavity mode during operation without repeated build up of lasing. In this context, we theoretically investigate the currently existing concepts of rapidly wavelength-swept lasers based on tuning of the cavity length or refractive index, leading to an altered optical path length inside the resonator. Specifically, we consider vertical-cavity surface-emitting lasers (VCSELs) with microelectromechanical system (MEMS) mirrors as well as Fourier domain mode-locked (FDML) and Vernier-tuned distributed Bragg reflector (VT-DBR) lasers. Based on heuristic arguments and exact analytical solutions of Maxwell's equations for a fundamental laser resonator model, we show that adiabatic wavelength tuning is achieved, i.e., hopping between cavity modes associated with a repeated build up of lasing is avoided, and the photon number is conserved. As a consequence, no fundamental limit exists for the wavelength tuning speed, in principle enabling wide-range wavelength sweeps at arbitrary tuning speeds with narrow instantaneous linewidth.
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Affiliation(s)
- Christian Jirauschek
- Institute for Nanoelectronics, Technische Universität München, Arcisstr. 21, D-80333 Munich,
Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, D-23562 Lübeck,
Germany
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, D-80538 Munich,
Germany
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43
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Quantitative optical coherence tomography angiography of vascular abnormalities in the living human eye. Proc Natl Acad Sci U S A 2015; 112:E2395-402. [PMID: 25897021 DOI: 10.1073/pnas.1500185112] [Citation(s) in RCA: 474] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Retinal vascular diseases are important causes of vision loss. A detailed evaluation of the vascular abnormalities facilitates diagnosis and treatment in these diseases. Optical coherence tomography (OCT) angiography using the highly efficient split-spectrum amplitude decorrelation angiography algorithm offers an alternative to conventional dye-based retinal angiography. OCT angiography has several advantages, including 3D visualization of retinal and choroidal circulations (including the choriocapillaris) and avoidance of dye injection-related complications. Results from six illustrative cases are reported. In diabetic retinopathy, OCT angiography can detect neovascularization and quantify ischemia. In age-related macular degeneration, choroidal neovascularization can be observed without the obscuration of details caused by dye leakage in conventional angiography. Choriocapillaris dysfunction can be detected in the nonneovascular form of the disease, furthering our understanding of pathogenesis. In choroideremia, OCT's ability to show choroidal and retinal vascular dysfunction separately may be valuable in predicting progression and assessing treatment response. OCT angiography shows promise as a noninvasive alternative to dye-based angiography for highly detailed, in vivo, 3D, quantitative evaluation of retinal vascular abnormalities.
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44
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Huang Y, Zhang Q, Wang RK. Efficient method to suppress artifacts caused by tissue hyper-reflections in optical microangiography of retina in vivo. BIOMEDICAL OPTICS EXPRESS 2015; 6:1195-208. [PMID: 25909004 PMCID: PMC4399659 DOI: 10.1364/boe.6.001195] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 01/17/2015] [Accepted: 02/24/2015] [Indexed: 05/20/2023]
Abstract
Optical microangiography (OMAG) is an optical coherence tomography (OCT)-based imaging technique that is capable of achieving the angiographic imaging of biological tissues in vivo with a high imaging resolution and no need for dye injection. OMAG has a potential to become a clinical tool for the diagnosis and treatment monitoring of various retinopathies. In principle, OMAG extracts blood flow information based on a direct differentiation of complex or intensity OCT signals between repeated B-scans acquired at the same cross section, which is sensitive to blood cell movement. In practice, this method is prone to artifacts due to tissue hyper-reflection, commonly seen in retinal diseases such as diabetic retinopathy. In this paper, we propose a novel method to suppress the artifacts induced by hyper-reflection. We propose to scale OMAG flow signals by a weighting factor that is motion-sensitive but hyper-reflection insensitive. We show that this simple weighting approach is effective in suppressing the artifacts due to tissue hyper-reflections while still maintaining the detected capillary networks with high fidelity, especially in deeper retina. The effectiveness of the proposed technique is demonstrated by a phantom study and case studies on patients' eyes with hyper-reflective foci. Finally we discuss potential applications of this technique.
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45
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Fechtig DJ, Grajciar B, Schmoll T, Blatter C, Werkmeister RM, Drexler W, Leitgeb RA. Line-field parallel swept source MHz OCT for structural and functional retinal imaging. BIOMEDICAL OPTICS EXPRESS 2015; 6:716-35. [PMID: 25798298 PMCID: PMC4361428 DOI: 10.1364/boe.6.000716] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/26/2015] [Accepted: 01/27/2015] [Indexed: 05/17/2023]
Abstract
We demonstrate three-dimensional structural and functional retinal imaging with line-field parallel swept source imaging (LPSI) at acquisition speeds of up to 1 MHz equivalent A-scan rate with sensitivity better than 93.5 dB at a central wavelength of 840 nm. The results demonstrate competitive sensitivity, speed, image contrast and penetration depth when compared to conventional point scanning OCT. LPSI allows high-speed retinal imaging of function and morphology with commercially available components. We further demonstrate a method that mitigates the effect of the lateral Gaussian intensity distribution across the line focus and demonstrate and discuss the feasibility of high-speed optical angiography for visualization of the retinal microcirculation.
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Affiliation(s)
- Daniel J. Fechtig
- Center for Med. Physics and Biomed. Engineering, Medical University Vienna, Waehringer Guertel 18-20, A-1090, Vienna,
Austria
- Christian Doppler Laboratory for Laser Development and their Application to Medicine and Biology, Center for Medical Physics and Biomedical Engineering, Medical University Vienna,
Austria
| | - Branislav Grajciar
- Center for Med. Physics and Biomed. Engineering, Medical University Vienna, Waehringer Guertel 18-20, A-1090, Vienna,
Austria
| | - Tilman Schmoll
- Carl Zeiss Meditec, Inc., 5160 Hacienda Drive, Dublin, CA 94568,
USA
| | - Cedric Blatter
- Center for Med. Physics and Biomed. Engineering, Medical University Vienna, Waehringer Guertel 18-20, A-1090, Vienna,
Austria
| | - Rene M. Werkmeister
- Center for Med. Physics and Biomed. Engineering, Medical University Vienna, Waehringer Guertel 18-20, A-1090, Vienna,
Austria
| | - Wolfgang Drexler
- Center for Med. Physics and Biomed. Engineering, Medical University Vienna, Waehringer Guertel 18-20, A-1090, Vienna,
Austria
- Christian Doppler Laboratory for Laser Development and their Application to Medicine and Biology, Center for Medical Physics and Biomedical Engineering, Medical University Vienna,
Austria
| | - Rainer A. Leitgeb
- Center for Med. Physics and Biomed. Engineering, Medical University Vienna, Waehringer Guertel 18-20, A-1090, Vienna,
Austria
- Christian Doppler Laboratory for Laser Development and their Application to Medicine and Biology, Center for Medical Physics and Biomedical Engineering, Medical University Vienna,
Austria
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46
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Moult E, Choi W, Waheed NK, Adhi M, Lee B, Lu CD, Jayaraman V, Potsaid B, Rosenfeld PJ, Duker JS, Fujimoto JG. Ultrahigh-speed swept-source OCT angiography in exudative AMD. Ophthalmic Surg Lasers Imaging Retina 2014; 45:496-505. [PMID: 25423628 PMCID: PMC4712918 DOI: 10.3928/23258160-20141118-03] [Citation(s) in RCA: 174] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 11/04/2014] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND OBJECTIVE To investigate the potential of ultrahigh-speed swept-source optical coherence tomography angiography (OCTA) to visualize retinal and choroidal vascular changes in patients with exudative age-related macular degeneration (AMD). PATIENTS AND METHODS Observational, prospective cross-sectional study. An ultrahigh-speed swept-source prototype was used to perform OCTA of the retinal and choriocapillaris microvasculature in 63 eyes of 32 healthy controls and 19 eyes of 15 patients with exudative AMD. MAIN OUTCOME MEASURE qualitative comparison of the retinal and choriocapillaris microvasculature in the two groups. RESULTS Choroidal neovascularization (CNV) was clearly visualized in 16 of the 19 eyes with exudative AMD, located above regions of severe choriocapillaris alteration. In 14 of these eyes, the CNV lesions were surrounded by regions of choriocapillaris alteration. CONCLUSION OCTA may offer noninvasive monitoring of the retinal and choriocapillaris microvasculature in patients with CNV, which may assist in diagnosis and monitoring.
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47
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48
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Wieser W, Draxinger W, Klein T, Karpf S, Pfeiffer T, Huber R. High definition live 3D-OCT in vivo: design and evaluation of a 4D OCT engine with 1 GVoxel/s. BIOMEDICAL OPTICS EXPRESS 2014; 5:2963-77. [PMID: 25401010 PMCID: PMC4230855 DOI: 10.1364/boe.5.002963] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 05/18/2023]
Abstract
We present a 1300 nm OCT system for volumetric real-time live OCT acquisition and visualization at 1 billion volume elements per second. All technological challenges and problems associated with such high scanning speed are discussed in detail as well as the solutions. In one configuration, the system acquires, processes and visualizes 26 volumes per second where each volume consists of 320 x 320 depth scans and each depth scan has 400 usable pixels. This is the fastest real-time OCT to date in terms of voxel rate. A 51 Hz volume rate is realized with half the frame number. In both configurations the speed can be sustained indefinitely. The OCT system uses a 1310 nm Fourier domain mode locked (FDML) laser operated at 3.2 MHz sweep rate. Data acquisition is performed with two dedicated digitizer cards, each running at 2.5 GS/s, hosted in a single desktop computer. Live real-time data processing and visualization are realized with custom developed software on an NVidia GTX 690 dual graphics processing unit (GPU) card. To evaluate potential future applications of such a system, we present volumetric videos captured at 26 and 51 Hz of planktonic crustaceans and skin.
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Affiliation(s)
- Wolfgang Wieser
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
| | - Wolfgang Draxinger
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
| | - Thomas Klein
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
| | - Sebastian Karpf
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
| | - Tom Pfeiffer
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
| | - Robert Huber
- Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck Germany
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49
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Leitgeb RA, Werkmeister RM, Blatter C, Schmetterer L. Doppler optical coherence tomography. Prog Retin Eye Res 2014; 41:26-43. [PMID: 24704352 PMCID: PMC4073226 DOI: 10.1016/j.preteyeres.2014.03.004] [Citation(s) in RCA: 227] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 03/21/2014] [Accepted: 03/26/2014] [Indexed: 11/19/2022]
Abstract
Optical Coherence Tomography (OCT) has revolutionized ophthalmology. Since its introduction in the early 1990s it has continuously improved in terms of speed, resolution and sensitivity. The technique has also seen a variety of extensions aiming to assess functional aspects of the tissue in addition to morphology. One of these approaches is Doppler OCT (DOCT), which aims to visualize and quantify blood flow. Such extensions were already implemented in time domain systems, but have gained importance with the introduction of Fourier domain OCT. Nowadays phase-sensitive detection techniques are most widely used to extract blood velocity and blood flow from tissues. A common problem with the technique is that the Doppler angle is not known and several approaches have been realized to obtain absolute velocity and flow data from the retina. Additional studies are required to elucidate which of these techniques is most promising. In the recent years, however, several groups have shown that data can be obtained with high validity and reproducibility. In addition, several groups have published values for total retinal blood flow. Another promising application relates to non-invasive angiography. As compared to standard techniques such as fluorescein and indocyanine-green angiography the technique offers two major advantages: no dye is required and depth resolution is required is provided. As such Doppler OCT has the potential to improve our abilities to diagnose and monitor ocular vascular diseases.
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Affiliation(s)
- Rainer A Leitgeb
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - René M Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Cedric Blatter
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Leopold Schmetterer
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria; Department of Clinical Pharmacology, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
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50
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Choi WJ, Reif R, Yousefi S, Wang RK. Improved microcirculation imaging of human skin in vivo using optical microangiography with a correlation mapping mask. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:36010. [PMID: 24623159 PMCID: PMC3951585 DOI: 10.1117/1.jbo.19.3.036010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 02/07/2014] [Accepted: 02/11/2014] [Indexed: 05/18/2023]
Abstract
Optical microangiography based on optical coherence tomography (OCT) is prone to noise that arises from a static tissue region. Here, we propose a method that can significantly reduce this noise. The method is developed based on an approach that uses the magnitude information of OCT signals to produce tissue microangiograms, especially suitable for the case where a swept-source OCT system is deployed. By combined use of two existing OCT microangiography methods-ultrahigh-sensitive optical microangiography (UHS-OMAG) and correlation mapping OCT (cmOCT)-the final tissue microangiogram is generated by masking UHS-OMAG image using the binary representation of cmOCT image. We find that this process masks the residual static artifacts while preserving the vessel structures. The noise rejection capability of the masked approach (termed as mOMAG) is tested on a tissue-like flow phantom as well as an in vivo human skin tissue. Compared to UHS-OMAG and cmOCT, we demonstrate that the proposed method is capable of achieving improved signal-to-noise ratio in providing microcirculation images. Finally, we show its clinical potential by quantitatively assessing the vascular difference between a burn scar and a normal skin of human subject in vivo.
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Affiliation(s)
- Woo June Choi
- University of Washington, Department of Bioengineering, Seattle, Washington 98195
| | - Roberto Reif
- University of Washington, Department of Bioengineering, Seattle, Washington 98195
| | - Siavash Yousefi
- University of Washington, Department of Bioengineering, Seattle, Washington 98195
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, Seattle, Washington 98195
- Address all correspondence to: Ruikang K. Wang, E-mail:
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