1
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Lee B, Jeong S, Lee J, Kim TS, Braaf B, Vakoc BJ, Oh WY. Wide-Field Three-Dimensional Depth-Invariant Cellular-Resolution Imaging of the Human Retina. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2203357. [PMID: 36642824 PMCID: PMC10023497 DOI: 10.1002/smll.202203357] [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: 05/31/2022] [Revised: 12/02/2022] [Indexed: 06/17/2023]
Abstract
Three-dimensional (3D) cellular-resolution imaging of the living human retina over a large field of view will bring a great impact in clinical ophthalmology, potentially finding new biomarkers for early diagnosis and improving the pathophysiological understanding of ocular diseases. While hardware-based and computational adaptive optics (AO) optical coherence tomography (OCT) have been developed to achieve cellular-resolution retinal imaging, these approaches support limited 3D imaging fields, and their high cost and intrinsic hardware complexity limit their practical utility. Here, this work demonstrates 3D depth-invariant cellular-resolution imaging of the living human retina over a 3 × 3 mm field of view using the first intrinsically phase-stable multi-MHz retinal swept-source OCT and novel computational defocus and aberration correction methods. Single-acquisition imaging of photoreceptor cells, retinal nerve fiber layer, and retinal capillaries is presented across unprecedented imaging fields. By providing wide-field 3D cellular-resolution imaging in the human retina using a standard point-scan architecture routinely used in the clinic, this platform proposes a strategy for expanded utilization of high-resolution retinal imaging in both research and clinical settings.
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Affiliation(s)
- ByungKun Lee
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- KI for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Sunhong Jeong
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- KI for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Joosung Lee
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- KI for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Tae Shik Kim
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston 02140, USA
| | - Boy Braaf
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston 02140, USA
| | - Benjamin J. Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston 02140, USA
| | - Wang-Yuhl Oh
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- KI for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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2
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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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3
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Wu M, Liu S, Leartprapun N, Adie S. Investigation of multiple scattering in space and spatial-frequency domains: with application to the analysis of aberration-diverse optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2021; 12:7478-7499. [PMID: 35003847 PMCID: PMC8713691 DOI: 10.1364/boe.439395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 05/12/2023]
Abstract
Optical microscopy suffers from multiple scattering (MS), which limits the optical imaging depth into scattering media. We previously demonstrated aberration-diverse optical coherence tomography (AD-OCT) for MS suppression, based on the principle that for datasets acquired with different aberration states of the imaging beam, MS backgrounds become decorrelated while single scattering (SS) signals remain correlated, so that a simple coherent average can be used to enhance the SS signal over the MS background. Here, we propose a space/spatial-frequency domain analysis framework for the investigation of MS in OCT, and apply the framework to compare AD-OCT (using astigmatic beams) to standard Gaussian-beam OCT via experiments in scattering tissue phantoms. Utilizing this framework, we found that increasing the astigmatic magnitude produced a large drop in both MS background and SS signal, but the decay experienced by the MS background was larger than the SS signal. Accounting for the decay in both SS signal and MS background, the overall signal-to-background ratio (SBR) of AD-OCT was similar to the Gaussian control after about 10 coherent averages, when deeper line foci was positioned at the plane-of-interest and the line foci spacing was smaller than or equal to 80 µm. For an even larger line foci spacing of 160 µm, AD-OCT resulted in a lower SBR than the Gaussian-beam control. This work provides an analysis framework to gain deeper levels of understanding and insights for the future study of MS and MS suppression in both the space and spatial-frequency domains.
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Affiliation(s)
- Meiqi Wu
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Siyang Liu
- School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Nichaluk Leartprapun
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Steven Adie
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
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4
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Joo J, Kim TS, Vakoc BJ, Oh WY. Robust and easy-to-operate stretched-pulse mode-locked wavelength-swept laser with an all-polarization-maintaining fiber cavity for 10 MHz A-line rate optical coherence tomography. OPTICS LETTERS 2021; 46:3857-3860. [PMID: 34388759 PMCID: PMC8455078 DOI: 10.1364/ol.424835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/01/2021] [Indexed: 05/18/2023]
Abstract
We demonstrate robust and easy-to-operate stretched-pulse mode-locked laser (SPML) architectures using all-polarization-maintaining fiber laser cavities. Because of the polarization-maintaining construction, the laser performance is unaffected by mechanical perturbation on the cavity fibers. The lasers automatically initiate linear-in-wavenumber sweeps across 100 nm centered at 1290 nm with a 10 MHz repetition rate. OCT imaging with a sensitivity of 98 dB and a single-sided 6 dB coherence length of 2.5 mm is demonstrated. OCT angiography of a mouse brain that visualized three-dimensional cerebral microvasculature over a field of 1.5mm×1.5mm (398 A-lines × 380 B-scans) at a rate of 5.26 volumes per second is also presented. The robust all-PMF SPML lasers are a turnkey, high-performance source for ultrahigh-speed OCT imaging.
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Affiliation(s)
- JongYoon Joo
- Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
- KI for Health Science and Technology, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Tae Shik Kim
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Benjamin J. Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Wang-Yuhl Oh
- Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
- KI for Health Science and Technology, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
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5
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Miao Y, Siadati M, Song J, Ma D, Jian Y, Beg MF, Sarunic MV, Ju MJ. Phase-corrected buffer averaging for enhanced OCT angiography using FDML laser. OPTICS LETTERS 2021; 46:3833-3836. [PMID: 34388753 DOI: 10.1364/ol.430915] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/07/2021] [Indexed: 05/18/2023]
Abstract
Megahertz-rate optical coherence tomography angiography (OCTA) is highly anticipated as an ultrafast imaging tool in clinical settings. However, shot-noise-limited sensitivity is inevitably reduced in high-speed imaging systems. In this Letter, we present a coherent buffer averaging technique for use with a Fourier-domain mode-locked (FDML) laser to improve OCTA contrast at 1060 nm MHz-rate retinal imaging. Full characterization of spectral variations among the FDML buffers and a numerical correction method are also presented, with the results demonstrating a 10-fold increase in the phase alignment among buffers. Coherent buffer averaging provided better OCTA contrast than the conventional multi-frame averaging approach with a faster acquisition time.
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6
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Choi S, Ota T, Nin F, Shioda T, Suzuki T, Hibino H. Rapid optical tomographic vibrometry using a swept multi-gigahertz comb. OPTICS EXPRESS 2021; 29:16749-16768. [PMID: 34154231 DOI: 10.1364/oe.425972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/10/2021] [Indexed: 06/13/2023]
Abstract
We propose a rapid tomographic vibrometer technique using an optical comb to measure internal vibrations, transient phenomena, and tomographic distributions in biological tissue and microelectromechanical system devices at high frequencies. This method allows phase-sensitive tomographic measurement in the depth direction at a multi-MHz scan rate using a frequency-modulated broadband electrooptic multi-GHz supercontinuum comb. The frequency spacing was swept instantaneously in time and axisymmetrically about the center wavelength via a dual-drive Mach-Zehnder modulator driven by a variable radio frequency signal. This unique sweeping method permits direct measurement of fringe-free interferometric amplitude and phase with arbitrarily changeable measurement range and scan rate. Therefore, a compressive measurement can be made in only the depth region where the vibration exists, reducing the number of measurement points. In a proof-of-principle experiment, the interferometric amplitude and phase were investigated for in-phase and quadrature phase-shifted interferograms obtained by a polarization demodulator. Tomographic transient displacement measurements were performed using a 0.12 mm thick glass film and piezo-electric transducer oscillating at 10-100 kHz with scan rates in the range 1-20 MHz. The depth resolution and precision of the vibrometer were estimated to be approximately 25 µm and 1.0 nm, respectively.
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7
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Nguyen TH, Ahsen OO, Liang K, Zhang J, Mashimo H, Fujimoto JG. Correction of circumferential and longitudinal motion distortion in high-speed catheter/endoscope-based optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2021; 12:226-246. [PMID: 33520383 PMCID: PMC7818954 DOI: 10.1364/boe.409074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/13/2020] [Accepted: 11/19/2020] [Indexed: 05/06/2023]
Abstract
Catheter/endoscope-based optical coherence tomography (OCT) is a powerful modality that visualizes structural information in luminal organs. Increases in OCT speed have reduced motion artifacts by enabling acquisition faster than or comparable to the time scales of physiological motion. However motion distortion remains a challenge because catheter/endoscope OCT imaging involves both circumferential and longitudinal scanning of tissue. This paper presents a novel image processing method to estimate and correct motion distortion in both the circumferential and longitudinal directions using a single en face image from a volumetric data set. The circumferential motion distortion is estimated and corrected using the en face image. Then longitudinal motion distortion is estimated and corrected using diversity of image features along the catheter pullback direction. Finally, the OCT volume is resampled and motion corrected. Results are presented on synthetic images and clinical OCT images of the human esophagus.
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Affiliation(s)
- Tan Huu Nguyen
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- PathAI Inc., 120 Brookline Ave, Boston, MA 02215, USA
| | - Osman Oguz Ahsen
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kaicheng Liang
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jason Zhang
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hiroshi Mashimo
- Veterans Affairs Boston Healthcare System, MA 02130, USA
- Havard Medical School, MA 02130, USA
| | - James G. Fujimoto
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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8
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Braaf B, Donner S, Uribe-Patarroyo N, Bouma BE, Vakoc BJ. A Neural Network Approach to Quantify Blood Flow from Retinal OCT Intensity Time-Series Measurements. Sci Rep 2020; 10:9611. [PMID: 32541887 PMCID: PMC7295995 DOI: 10.1038/s41598-020-66158-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 05/12/2020] [Indexed: 12/31/2022] Open
Abstract
Many diseases of the eye are associated with alterations in the retinal vasculature that are possibly preceded by undetected changes in blood flow. In this work, a robust blood flow quantification framework is presented based on optical coherence tomography (OCT) angiography imaging and deep learning. The analysis used a forward signal model to simulate OCT blood flow data for training of a neural network (NN). The NN was combined with pre- and post-processing steps to create an analysis framework for measuring flow rates from individual blood vessels. The framework’s accuracy was validated using both blood flow phantoms and human subject imaging, and across flow speed, vessel angle, hematocrit levels, and signal-to-noise ratio. The reported flow rate of the calibrated NN framework was measured to be largely independent of vessel angle, hematocrit levels, and measurement signal-to-noise ratio. In vivo retinal flow rate measurements were self-consistent across vascular branch points, and approximately followed a predicted power-law dependence on the vessel diameter. The presented OCT-based NN flow rate estimation framework addresses the need for a robust, deployable, and label-free quantitative retinal blood flow mapping technique.
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Affiliation(s)
- Boy Braaf
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA
| | | | - Néstor Uribe-Patarroyo
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Brett E Bouma
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Benjamin J Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA. .,Harvard Medical School, Boston, MA, USA.
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9
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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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10
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Yao X, Devarajan K, Werkmeister RM, dos Santos VA, Ang M, Kuo A, Wong DWK, Chua J, Tan B, Barathi VA, Schmetterer L. In vivo corneal endothelium imaging using ultrahigh resolution OCT. BIOMEDICAL OPTICS EXPRESS 2019; 10:5675-5686. [PMID: 31799039 PMCID: PMC6865113 DOI: 10.1364/boe.10.005675] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 08/19/2019] [Accepted: 08/20/2019] [Indexed: 05/03/2023]
Abstract
We investigate the influence of optical coherence tomography (OCT) system resolution on high-quality in vivo en face corneal endothelial cell images of the monkey eye, to allow for quantitative analysis of cell density. We vary the lateral resolution of the ultrahigh resolution (UHR) OCT system (centered at 850 nm) by using different objectives, and the axial resolution by windowing the source spectrum. By suppressing the motion of the animal, we are able to obtain a high-quality en face corneal endothelial cell map in vivo using UHR OCT for the first time with a lateral resolution of 3.1 µm. Increasing lateral resolution did not result in a better image quality but a smaller field of view (FOV), and the axial resolution had little impact on the visualization of corneal endothelial cells. Quantitative analysis of cell density was performed on in vivo en face OCT images of corneal endothelial cells, and the results are in agreement with previously reported data. Our study may offer a practical guideline for designing OCT systems that allow for in vivo corneal endothelial cell imaging with high quality.
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Affiliation(s)
- Xinwen Yao
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore
- These authors equally contributed to this work
| | - Kavya Devarajan
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- These authors equally contributed to this work
| | - René M. Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | | | - Marcus Ang
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
| | - Anthony Kuo
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
- Department of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Damon W. K. Wong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore
- NTU Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore
| | - Jacqueline Chua
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore
- Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
| | - Bingyao Tan
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore
| | - Veluchamy Amutha Barathi
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
| | - Leopold Schmetterer
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
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11
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Pijewska E, Gorczynska I, Szkulmowski M. Computationally effective 2D and 3D fast phase unwrapping algorithms and their applications to Doppler optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2019; 10:1365-1382. [PMID: 30891352 PMCID: PMC6420292 DOI: 10.1364/boe.10.001365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/20/2019] [Accepted: 01/22/2019] [Indexed: 05/07/2023]
Abstract
We propose a simplification for a robust and easy to implement fast phase unwrapping (FPU) algorithm that is used to solve the phase wrapping problem encountered in various fields of optical imaging and metrology. We show that the number of necessary computations using the algorithm can be reduced compared to its original version. FPU can be easily extended from two to three spatial dimensions. We demonstrate the applicability of the two- and three-dimensional FPU algorithm for Doppler optical coherence tomography (DOCT) in numerical simulations, and in the imaging of a flow phantom and blood flow in the human retina in vivo. We introduce an FPU applicability plot for use as a guide in the selection of the most suitable version of the algorithm depending on the phase noise in the acquired data. This plot uses the circular standard deviation of the wrapped phase distribution as a measure of noise and relates it to the root-mean-square error of the recovered, unwrapped phase.
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12
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Liu S, Lamont MRE, Mulligan JA, Adie SG. Aberration-diverse optical coherence tomography for suppression of multiple scattering and speckle. BIOMEDICAL OPTICS EXPRESS 2018; 9:4919-4935. [PMID: 30319912 PMCID: PMC6179412 DOI: 10.1364/boe.9.004919] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/06/2018] [Accepted: 09/07/2018] [Indexed: 05/05/2023]
Abstract
Multiple scattering is a major barrier that limits the optical imaging depth in scattering media. In order to alleviate this effect, we demonstrate aberration-diverse optical coherence tomography (AD-OCT), which exploits the phase correlation between the deterministic signals from single-scattered photons to suppress the random background caused by multiple scattering and speckle. AD-OCT illuminates the sample volume with diverse aberrated point spread functions, and computationally removes these intentionally applied aberrations. After accumulating 12 astigmatism-diverse OCT volumes, we show a 10 dB enhancement in signal-to-background ratio via a coherent average of reconstructed signals from a USAF target located 7.2 scattering mean free paths below a thick scattering layer, and a 3× speckle contrast reduction from an incoherent average of reconstructed signals inside the scattering layer. This AD-OCT method, when implemented using astigmatic illumination, is a promising approach for ultra-deep volumetric optical coherence microscopy.
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Affiliation(s)
- Siyang Liu
- School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Michael R. E. Lamont
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Jeffrey A. Mulligan
- School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Steven G. Adie
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
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13
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Liu S, Mulligan JA, Adie SG. Volumetric optical coherence microscopy with a high space-bandwidth- time product enabled by hybrid adaptive optics. BIOMEDICAL OPTICS EXPRESS 2018; 9:3137-3152. [PMID: 29984088 PMCID: PMC6033577 DOI: 10.1364/boe.9.003137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 05/31/2018] [Accepted: 05/31/2018] [Indexed: 05/06/2023]
Abstract
Optical coherence microscopy (OCM) is a promising modality for high resolution imaging, but has limited ability to capture large-scale volumetric information about dynamic biological processes with cellular resolution. To enhance the throughput of OCM, we implemented a hybrid adaptive optics (hyAO) approach that combines computational adaptive optics with an intentionally aberrated imaging beam generated via hardware adaptive optics. Using hyAO, we demonstrate the depth-equalized illumination and collection ability of an astigmatic beam compared to a Gaussian beam for cellular-resolution imaging. With this advantage, we achieved volumetric OCM with a higher space-bandwidth-time product compared to Gaussian-beam acquisition that employed focus-scanning across depth. HyAO was also used to perform volumetric time-lapse OCM imaging of cellular dynamics over a 1mm × 1mm × 1mm field-of-view with 2 μm isotropic spatial resolution and 3-minute temporal resolution. As hyAO is compatible with both spectral-domain and swept-source beam-scanning OCM systems, significant further improvements in absolute volumetric throughput are possible by use of ultrahigh-speed swept sources.
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Affiliation(s)
- Siyang Liu
- School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Jeffrey A. Mulligan
- School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Steven G. Adie
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
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