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Ayubi GA, Dubra A. Robust real-time estimation of non-uniform angular velocity and sub-pixel jitter in images captured with resonant scanners. OPTICS EXPRESS 2023; 31:44199-44211. [PMID: 38178497 DOI: 10.1364/oe.512233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 12/05/2023] [Indexed: 01/06/2024]
Abstract
Images captured with resonant scanners are affected by angular velocity fluctuations that result in image distortion and by poor synchronization between scanning and light detection that creates jitter between image rows. We previously demonstrated that both problems can be mitigated in post-processing by recording the scanner orientation in synchrony with the image capture, followed by data resampling [Opt. Express30, 112 (2022)10.1364/OE.446162]. Here we introduce more robust algorithms for estimation of both angular velocity fluctuation and jitter in the presence of random and deterministic noise. We also show linearization of the scanner oscillation model to reduce calculation times by two orders of magnitude, reaching 65,000 jitter estimations per second when using 2,800 samples per image row, and 500,000 when using only 500 samples, easily supporting real-time generation of jitter-corrected images.
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2
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Kowalski B, Akondi V, Dubra A. Correction of non-uniform angular velocity and sub-pixel jitter in optical scanning. OPTICS EXPRESS 2022; 30:112-124. [PMID: 35201185 PMCID: PMC8970701 DOI: 10.1364/oe.446162] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/10/2021] [Accepted: 12/10/2021] [Indexed: 05/08/2023]
Abstract
Optical scanners are widely used in high-resolution scientific, medical, and industrial devices. The accuracy and precision of these instruments are often limited by angular speed fluctuations due to rotational inertia and by poor synchronization between scanning and light detection, respectively. Here we demonstrate that both problems can be mitigated by recording scanner orientation in synchrony with light detection, followed by data resampling. This approach is illustrated with synthetic and experimental data from a point-scanning microscope with a resonant scanner and a non-resonant scanner. Fitting of the resonant scanner orientation data to a cosine model was used to correct image warping and sampling jitter, as well as to precisely interleave image lines collected during the clockwise and counterclockwise resonant scanner portions of the rotation cycle. Vertical scanner orientation data interpolation was used to correct image distortion due to angular speed fluctuations following abrupt control signal changes.
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Affiliation(s)
| | - Vyas Akondi
- Byers Eye Institute, Stanford University, Palo Alto, CA 94303, USA
| | - Alfredo Dubra
- Byers Eye Institute, Stanford University, Palo Alto, CA 94303, USA
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3
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Wei X, Hormel TT, Jia Y. Phase-stabilized complex-decorrelation angiography. BIOMEDICAL OPTICS EXPRESS 2021; 12:2419-2431. [PMID: 33996238 PMCID: PMC8086438 DOI: 10.1364/boe.420503] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/20/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
In this study, we developed a novel phase-stabilized complex-decorrelation (PSCD) optical coherence tomography (OCT) angiography (OCTA) method that can generate high quality OCTA images. This method has been validated using three different types of OCT systems and compared with conventional complex- and amplitude-based OCTA algorithms. Our results suggest that in combination with a pre-processing phase stabilization method, the PSCD method is insensitive to bulk motion phase shifts, less dependent on OCT reflectance than conventional complex methods and demonstrates extended dynamic range of flow signal, in contrast to other two methods.
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Affiliation(s)
- Xiang Wei
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
- Department of Biomedical Engineer, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Tristan T. Hormel
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Yali Jia
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
- Department of Biomedical Engineer, Oregon Health and Science University, Portland, Oregon 97239, USA
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4
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Optical coherence tomography angiography in preclinical neuroimaging. Biomed Eng Lett 2019; 9:311-325. [PMID: 31456891 DOI: 10.1007/s13534-019-00118-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/29/2019] [Accepted: 06/27/2019] [Indexed: 01/22/2023] Open
Abstract
Preclinical neuroimaging allows for the assessment of brain anatomy, connectivity, and function in laboratory animals, such as mice and this imaging field has been a rapidly growing aimed at bridging the translation gap between animal and human research. The progress in the animal research could be accelerated by high-resolution in vivo optical imaging technologies. Optical coherence tomography-based angiography (OCTA) estimates the scattering from moving red blood cells, providing the visualization of functional micro-vessel networks within tissue beds in vivo without a need for exogenous contrast agents. Recent advancement of OCTA methods have expanded its application to neuroimaging of small animal models of brain disorders. In this paper, we overview the recent development of OCTA techniques for blood flow imaging and its preclinical applications in neuroimaging. In specific, a summary of preclinical OCTA studies for traumatic brain injury, cerebral stroke, and aging brain on mice is reviewed.
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5
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Yamanari M, Uematsu S, Ishihara K, Ikuno Y. Parallel detection of Jones-matrix elements in polarization-sensitive optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2019; 10:2318-2336. [PMID: 31149375 PMCID: PMC6524579 DOI: 10.1364/boe.10.002318] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/16/2019] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
The polarization properties of a sample can be characterized using a Jones matrix. To measure the Jones matrix without assumptions of the sample, two different incident states of polarization are usually used. This requirement often causes certain drawbacks in polarization-sensitive optical coherence tomography (PS-OCT), e.g., a decrease in the effective A-scan rate or axial depth range, if a multiplexing scheme is used. Because both the A-scan rate and axial depth range are important for clinical applications, including the imaging of an anterior eye segment, a new PS-OCT method that does not have these drawbacks is desired. Here, we present a parallel-detection approach that maintains the same A-scan rate and axial measurement range as conventional OCT. The interferometer consists of fiber-optic components, most of which are polarization-maintaining components with fast-axis blocking free from polarization management. When a parallel detection is implemented using swept-source OCT (SS-OCT), synchronization between the A-scans and synchronization between the detection channels have critical effects on the Jones-matrix measurement. Because it is difficult to achieve perfect synchronization using only hardware, we developed a solution using a numerical correction with signals from a static mirror. Using the developed system, we demonstrate the imaging of an anterior eye segment from the cornea to the back surface of the crystalline lens.
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Affiliation(s)
- Masahiro Yamanari
- Engineering Department, Tomey Corporation, 2-11-33 Noritakeshinmachi, Nishiku, Nagoya, Aichi, 451-0051, Japan
| | - Sato Uematsu
- Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Kenji Ishihara
- Engineering Department, Tomey Corporation, 2-11-33 Noritakeshinmachi, Nishiku, Nagoya, Aichi, 451-0051, Japan
| | - Yasushi Ikuno
- Ikuno Eye Center, 2-9-10 3F Juso-Higashi, Yodogawaku, Osaka, Osaka, 532-0023, Japan
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6
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Son T, Alam M, Toslak D, Wang B, Lu Y, Yao X. Functional optical coherence tomography of neurovascular coupling interactions in the retina. JOURNAL OF BIOPHOTONICS 2018; 11:e201800089. [PMID: 29770594 PMCID: PMC6239985 DOI: 10.1002/jbio.201800089] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/15/2018] [Indexed: 05/19/2023]
Abstract
Quantitative evaluation of retinal neurovascular coupling is essential for a better understanding of visual function and early detection of eye diseases. However, there is no established method to monitor coherent interactions between stimulus-evoked neural activity and hemodynamic responses at high resolution. Here, we report a multimodal functional optical coherence tomography (OCT) imaging methodology to enable concurrent intrinsic optical signal (IOS) imaging of stimulus-evoked neural activity and hemodynamic responses at capillary resolution. OCT angiography guided IOS analysis was used to separate neural-IOS and hemodynamic-IOS changes in the same retinal image sequence. Frequency flicker stimuli evoked neural-IOS changes in the outer retina; that is, photoreceptor layer, first and then in the inner retina, including outer plexus layer (OPL), inner plexiform layer (IPL), and ganglion cell layer (GCL), which were followed by hemodynamic-IOS changes primarily in the inner retina; that is, OPL, IPL, and GCL. Different time courses and signal magnitudes of hemodynamic-IOS responses were observed in blood vessels with various diameters.
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Affiliation(s)
- Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Minhaj Alam
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Devrim Toslak
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Ophthalmology, Antalya Training and Research Hospital, Antalya, Turkey
| | - Benquan Wang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
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7
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Eugui P, Lichtenegger A, Augustin M, Harper DJ, Muck M, Roetzer T, Wartak A, Konegger T, Widhalm G, Hitzenberger CK, Woehrer A, Baumann B. Beyond backscattering: optical neuroimaging by BRAD. BIOMEDICAL OPTICS EXPRESS 2018; 9:2476-2494. [PMID: 30258667 PMCID: PMC6154182 DOI: 10.1364/boe.9.002476] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/13/2018] [Accepted: 04/26/2018] [Indexed: 05/20/2023]
Abstract
Optical coherence tomography (OCT) is a powerful technology for rapid volumetric imaging in biomedicine. The bright field imaging approach of conventional OCT systems is based on the detection of directly backscattered light, thereby waiving the wealth of information contained in the angular scattering distribution. Here we demonstrate that the unique features of few-mode fibers (FMF) enable simultaneous bright and dark field (BRAD) imaging for OCT. As backscattered light is picked up by the different modes of a FMF depending upon the angular scattering pattern, we obtain access to the directional scattering signatures of different tissues by decoupling illumination and detection paths. We exploit the distinct modal propagation properties of the FMF in concert with the long coherence lengths provided by modern wavelength-swept lasers to achieve multiplexing of the different modal responses into a combined OCT tomogram. We demonstrate BRAD sensing for distinguishing differently sized microparticles and showcase the performance of BRAD-OCT imaging with enhanced contrast for ex vivo tumorous tissue in glioblastoma and neuritic plaques in Alzheimer's disease.
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Affiliation(s)
- Pablo Eugui
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna,
Austria
| | - Antonia Lichtenegger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna,
Austria
| | - Marco Augustin
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna,
Austria
| | - Danielle J. Harper
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna,
Austria
| | - Martina Muck
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna,
Austria
- Institute of Neurology, General Hospital and Medical University of Vienna, Vienna,
Austria
| | - Thomas Roetzer
- Institute of Neurology, General Hospital and Medical University of Vienna, Vienna,
Austria
| | - Andreas Wartak
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna,
Austria
| | - Thomas Konegger
- Institute of Chemical Technologies and Analytics, TU Wien, Vienna,
Austria
| | - Georg Widhalm
- Department of Neurosurgery, General Hospital and Medical University of Vienna, Vienna,
Austria
| | - Christoph K. Hitzenberger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna,
Austria
| | - Adelheid Woehrer
- Institute of Neurology, General Hospital and Medical University of Vienna, Vienna,
Austria
| | - Bernhard Baumann
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna,
Austria
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8
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Liu G, Yang J, Wang J, Li Y, Zang P, Jia Y, Huang D. Extended axial imaging range, widefield swept source optical coherence tomography angiography. JOURNAL OF BIOPHOTONICS 2017; 10:1464-1472. [PMID: 28493437 PMCID: PMC6145849 DOI: 10.1002/jbio.201600325] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 05/05/2023]
Abstract
We developed a high-speed, swept source OCT system for widefield OCT angiography (OCTA) imaging. The system has an extended axial imaging range of 6.6 mm. An electrical lens is used for fast, automatic focusing. The recently developed split-spectrum amplitude and phase-gradient angiography allow high-resolution OCTA imaging with only two B-scan repetitions. An improved post-processing algorithm effectively removed trigger jitter artifacts and reduced noise in the flow signal. We demonstrated high contrast 3 mm×3 mm OCTA image with 400×400 pixels acquired in 3 seconds and high-definition 8 mm×6 mm and 12 mm×6 mm OCTA images with 850×400 pixels obtained in 4 seconds. A widefield 8 mm×11 mm OCTA image is produced by montaging two 8 mm×6 mm scans. An ultra-widefield (with a maximum of 22 mm along both vertical and horizontal directions) capillary-resolution OCTA image is obtained by montaging six 12 mm×6 mm scans.
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Affiliation(s)
- Gangjun Liu
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Jianlong Yang
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Jie Wang
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Yan Li
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Pengxiao Zang
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Yali Jia
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - David Huang
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
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9
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Gao SS, Jia Y, Zhang M, Su JP, Liu G, Hwang TS, Bailey ST, Huang D. Optical Coherence Tomography Angiography. Invest Ophthalmol Vis Sci 2017; 57:OCT27-36. [PMID: 27409483 PMCID: PMC4968919 DOI: 10.1167/iovs.15-19043] [Citation(s) in RCA: 239] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Optical coherence tomography angiography (OCTA) is a noninvasive approach that can visualize blood vessels down to the capillary level. With the advent of high-speed OCT and efficient algorithms, practical OCTA of ocular circulation is now available to ophthalmologists. Clinical investigations that used OCTA have increased exponentially in the past few years. This review will cover the history of OCTA and survey its most important clinical applications. The salient problems in the interpretation and analysis of OCTA are described, and recent advances are highlighted.
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10
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Bai Y, Nichols JJ. Advances in thickness measurements and dynamic visualization of the tear film using non-invasive optical approaches. Prog Retin Eye Res 2017; 58:28-44. [DOI: 10.1016/j.preteyeres.2017.02.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/09/2017] [Accepted: 02/20/2017] [Indexed: 12/13/2022]
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11
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Yang J, Liu L, Campbell JP, Huang D, Liu G. Handheld optical coherence tomography angiography. BIOMEDICAL OPTICS EXPRESS 2017; 8:2287-2300. [PMID: 28736672 PMCID: PMC5516829 DOI: 10.1364/boe.8.002287] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 02/25/2017] [Accepted: 03/12/2017] [Indexed: 05/03/2023]
Abstract
We developed a handheld optical coherence tomography angiography (OCTA) system using a 100-kHz swept-source laser. The handheld probe weighs 0.4 kg and measures 20.6 × 12.8 × 4.6 cm3. The system has dedicated features for handheld operation. The probe is equipped with a mini iris camera for easy alignment. Real-time display of the en face OCT and cross-sectional OCT images in the system allows accurately locating the imaging target. Fast automatic focusing was achieved by an electrically tunable lens controlled by a golden-section search algorithm. An extended axial imaging range of 6 mm allows easy alignment. A registration algorithm using cross-correlation to register adjacent OCT B-frames with propagation from the central frame was used to effectively minimize motion artifacts in volumetric OCTA images captured in relatively short durations of 1 and 2.1 seconds. 2.5 × 2.5 mm (200 × 200 pixels) and 3.5 × 3.5 mm (300 × 300 pixels) retinal angiograms were demonstrated on two awake adult human subjects without the use of any mydriatic eye drops.
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12
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Ling Y, Gan Y, Yao X, Hendon CP. Phase-noise analysis of swept-source optical coherence tomography systems. OPTICS LETTERS 2017; 42:1333-1336. [PMID: 28362762 PMCID: PMC6080202 DOI: 10.1364/ol.42.001333] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We propose a new model to characterize the phase noise in swept-source optical coherence tomography (SS-OCT). The new model explicitly incorporates scanning variability, timing jitter, and sample location in addition to intensity noise (shot noise). The model was analyzed and validated by using both Monte Carlo methods and experiments. We suggest that the proposed model can be used as a guideline for future SS-OCT experimental designs.
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13
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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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14
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Son T, Wang B, Thapa D, Lu Y, Chen Y, Cao D, Yao X. Optical coherence tomography angiography of stimulus evoked hemodynamic responses in individual retinal layers. BIOMEDICAL OPTICS EXPRESS 2016; 7:3151-62. [PMID: 27570706 PMCID: PMC4986822 DOI: 10.1364/boe.7.003151] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 06/08/2016] [Accepted: 06/10/2016] [Indexed: 05/05/2023]
Abstract
Blood flow changes are highly related to neural activities in the retina. It has been reported that neural activity increases when flickering light stimulation of the retina is used. It is known that blood flow changes with flickering light stimulation can be altered in patients with vascular disease and that measurement of flicker-induced vasodilatation is an easily applied tool for monitoring functional microvascular alterations. However, details of distortions in retinal neurovascular coupling associated with major eye diseases are not well understood due to the limitation of existing techniques. In this study, flickering light stimulation was applied to mouse retinas to investigate stimulus evoked hemodynamic responses in individual retinal layers. A spectral domain optical coherence tomography (OCT) angiography imaging system was developed to provide dynamic mapping of hemodynamic responses in the ganglion cell layer, inner plexiform layer, outer plexiform layer and choroid layer before, during and after flickering light stimulation. Experimental results showed hemodynamic responses with different magnitudes and time courses in individual retinal layers. We anticipate that the dynamic OCT angiography of stimulus evoked hemodynamic responses can greatly foster the study of neurovascular coupling mechanisms in the retina, promising new biomarkers for retinal disease detection and diagnosis.
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Affiliation(s)
- Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Benquan Wang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Damber Thapa
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yanjun Chen
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Dingcai Cao
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
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15
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Nandy S, Salehi HS, Wang T, Wang X, Sanders M, Kueck A, Brewer M, Zhu Q. Correlating optical coherence elastography based strain measurements with collagen content of the human ovarian tissue. BIOMEDICAL OPTICS EXPRESS 2015; 6:3806-11. [PMID: 26504631 PMCID: PMC4605040 DOI: 10.1364/boe.6.003806] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 08/27/2015] [Accepted: 08/30/2015] [Indexed: 05/06/2023]
Abstract
In this manuscript, the initial feasibility of a catheter based phase stabilized swept source optical coherence tomography (OCT) system was studied for characterization of the strain inside different human ovarian tissue groups. The ovarian tissue samples were periodically compressed with 500 Hz square wave signal along the axial direction between the surface of an unfocused transducer and a glass cover slide. The displacement and corresponding strain were calculated during loading from different locations for each tissue sample. A total of 27 ex vivo ovaries from 16 patients were investigated. Statistically significant difference (p < 0.001) was observed between the average displacement and strain of the normal and malignant tissue groups. A sensitivity of 93.2% and a specificity of 83% were achieved using 25 microstrain (με) as the threshold. The collagen content of the tissues was quantified from the Sirius Red stained histological sections. The average collagen area fraction (CAF) obtained from the tissue groups were found to have a strong negative correlation (R = -0.75, p < 0.0001) with the amount of strain inside the tissue. This indicates much softer and degenerated tissue structure for the malignant ovaries as compared to the dense, collagen rich structure of the normal ovarian tissue. The initial results indicate that the swept source OCT system can be useful for estimating the elasticity of the human ovarian tissue.
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Affiliation(s)
- Sreyankar Nandy
- University of Connecticut, Department of Biomedical Engineering, Storrs, CT 06269, USA
| | - Hassan S. Salehi
- University of Connecticut, Department of Electrical and Computer Engineering, Storrs, CT 06269, USA
| | - Tianheng Wang
- University of Connecticut, Department of Electrical and Computer Engineering, Storrs, CT 06269, USA
| | - Xiaohong Wang
- University of Connecticut Health Center, Division of Pathology, Farmington, CT 06030, USA
| | - Melinda Sanders
- University of Connecticut Health Center, Division of Pathology, Farmington, CT 06030, USA
| | - Angela Kueck
- University of Connecticut Health Center, Division of Gynecologic Oncology, Farmington, CT 06030, USA
| | - Molly Brewer
- University of Connecticut Health Center, Division of Gynecologic Oncology, Farmington, CT 06030, USA
| | - Quing Zhu
- University of Connecticut, Department of Biomedical Engineering, Storrs, CT 06269, USA
- University of Connecticut, Department of Electrical and Computer Engineering, Storrs, CT 06269, USA
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16
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Su JP, Li Y, Tang M, Liu L, Pechauer AD, Huang D, Liu G. Imaging the anterior eye with dynamic-focus swept-source optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:126002. [PMID: 26662065 PMCID: PMC4674840 DOI: 10.1117/1.jbo.20.12.126002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 11/02/2015] [Indexed: 05/20/2023]
Abstract
A custom-built dynamic-focus swept-source optical coherence tomography (SS-OCT) system with a central wavelength of 1310 nm was used to image the anterior eye from the cornea to the lens. An electrically tunable lens was utilized to dynamically control the positions of focusing planes over the imaging range of 10 mm. The B-scan images were acquired consecutively at the same position but with different focus settings. The B-scan images were then registered and averaged after filtering the out-of-focus regions using a Gaussian window. By fusing images obtained at different depth focus locations, high-resolution and high signal-strength images were obtained over the entire imaging depth. In vivo imaging of human anterior segment was demonstrated. The performance of the system was compared with two commercial OCT systems. The human eye ciliary body was better visualized with the dynamic-focusing SS-OCT system than using the commercial 840 and 1310 nm OCT systems. The sulcus-to-sulcus distance was measured, and the result agreed with that acquired with ultrasound biomicroscopy
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Affiliation(s)
- Johnny P. Su
- Oregon Health and Science University, Casey Eye Institute, 3375 SW Terwilliger Boulevard, Portland, Oregon 97239, United States
| | - Yan Li
- Oregon Health and Science University, Casey Eye Institute, 3375 SW Terwilliger Boulevard, Portland, Oregon 97239, United States
| | - Maolong Tang
- Oregon Health and Science University, Casey Eye Institute, 3375 SW Terwilliger Boulevard, Portland, Oregon 97239, United States
| | - Liang Liu
- Oregon Health and Science University, Casey Eye Institute, 3375 SW Terwilliger Boulevard, Portland, Oregon 97239, United States
| | - Alex D. Pechauer
- Oregon Health and Science University, Casey Eye Institute, 3375 SW Terwilliger Boulevard, Portland, Oregon 97239, United States
| | - David Huang
- Oregon Health and Science University, Casey Eye Institute, 3375 SW Terwilliger Boulevard, Portland, Oregon 97239, United States
| | - Gangjun Liu
- Oregon Health and Science University, Casey Eye Institute, 3375 SW Terwilliger Boulevard, Portland, Oregon 97239, United States
- Address all correspondence to: Gangjun Liu, E-mail:
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