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Meng L, Huang M, Feng S, Wang Y, Lu J, Li P. Optical Flow-Based Full-Field Quantitative Blood-Flow Velocimetry Using Temporal Direction Filtering and Peak Interpolation. Int J Mol Sci 2023; 24:12048. [PMID: 37569421 PMCID: PMC10419297 DOI: 10.3390/ijms241512048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/15/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
The quantitative measurement of the microvascular blood-flow velocity is critical to the early diagnosis of microvascular dysfunction, yet there are several challenges with the current quantitative flow velocity imaging techniques for the microvasculature. Optical flow analysis allows for the quantitative imaging of the blood-flow velocity with a high spatial resolution, using the variation in pixel brightness between consecutive frames to trace the motion of red blood cells. However, the traditional optical flow algorithm usually suffers from strong noise from the background tissue, and a significant underestimation of the blood-flow speed in blood vessels, due to the errors in detecting the feature points in optical images. Here, we propose a temporal direction filtering and peak interpolation optical flow method (TPIOF) to suppress the background noise, and improve the accuracy of the blood-flow velocity estimation. In vitro phantom experiments and in vivo animal experiments were performed to validate the improvements in our new method.
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Affiliation(s)
- Liangwei Meng
- Britton Chance Center for Biomedical Photonics and MoE Key Laboratory for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China; (L.M.); (M.H.); (Y.W.); (J.L.)
- Research Unit of Multimodal Cross Scale Neural Signal Detection and Imaging, Chinese Academy of Medical Science, HUST-Suzhou Institute for Brainsmatics, Jiangsu Industrial Technology Reserch Institute (JITRI), Suzhou 215100, China
| | - Mange Huang
- Britton Chance Center for Biomedical Photonics and MoE Key Laboratory for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China; (L.M.); (M.H.); (Y.W.); (J.L.)
- Research Unit of Multimodal Cross Scale Neural Signal Detection and Imaging, Chinese Academy of Medical Science, HUST-Suzhou Institute for Brainsmatics, Jiangsu Industrial Technology Reserch Institute (JITRI), Suzhou 215100, China
| | - Shijie Feng
- Britton Chance Center for Biomedical Photonics and MoE Key Laboratory for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China; (L.M.); (M.H.); (Y.W.); (J.L.)
- Research Unit of Multimodal Cross Scale Neural Signal Detection and Imaging, Chinese Academy of Medical Science, HUST-Suzhou Institute for Brainsmatics, Jiangsu Industrial Technology Reserch Institute (JITRI), Suzhou 215100, China
| | - Yiqian Wang
- Britton Chance Center for Biomedical Photonics and MoE Key Laboratory for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China; (L.M.); (M.H.); (Y.W.); (J.L.)
- Research Unit of Multimodal Cross Scale Neural Signal Detection and Imaging, Chinese Academy of Medical Science, HUST-Suzhou Institute for Brainsmatics, Jiangsu Industrial Technology Reserch Institute (JITRI), Suzhou 215100, China
| | - Jinling Lu
- Britton Chance Center for Biomedical Photonics and MoE Key Laboratory for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China; (L.M.); (M.H.); (Y.W.); (J.L.)
- Research Unit of Multimodal Cross Scale Neural Signal Detection and Imaging, Chinese Academy of Medical Science, HUST-Suzhou Institute for Brainsmatics, Jiangsu Industrial Technology Reserch Institute (JITRI), Suzhou 215100, China
| | - Pengcheng Li
- Britton Chance Center for Biomedical Photonics and MoE Key Laboratory for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China; (L.M.); (M.H.); (Y.W.); (J.L.)
- Research Unit of Multimodal Cross Scale Neural Signal Detection and Imaging, Chinese Academy of Medical Science, HUST-Suzhou Institute for Brainsmatics, Jiangsu Industrial Technology Reserch Institute (JITRI), Suzhou 215100, China
- Department of Biomedical Engineering, Hainan University, Haikou 570228, China
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2
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Stamenkovic S, Li Y, Waters J, Shih A. Deep Imaging to Dissect Microvascular Contributions to White Matter Degeneration in Rodent Models of Dementia. Stroke 2023; 54:1403-1415. [PMID: 37094035 PMCID: PMC10460612 DOI: 10.1161/strokeaha.122.037156] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
The increasing socio-economic burden of Alzheimer disease (AD) and AD-related dementias has created a pressing need to define targets for therapeutic intervention. Deficits in cerebral blood flow and neurovascular function have emerged as early contributors to disease progression. However, the cause, progression, and consequence of small vessel disease in AD/AD-related dementias remains poorly understood, making therapeutic targets difficult to pinpoint. Animal models that recapitulate features of AD/AD-related dementias may provide mechanistic insight because microvascular pathology can be studied as it develops in vivo. Recent advances in in vivo optical and ultrasound-based imaging of the rodent brain facilitate this goal by providing access to deeper brain structures, including white matter and hippocampus, which are more vulnerable to injury during cerebrovascular disease. Here, we highlight these novel imaging approaches and discuss their potential for improving our understanding of vascular contributions to AD/AD-related dementias.
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Affiliation(s)
- Stefan Stamenkovic
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Yuandong Li
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Jack Waters
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Andy Shih
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Allen Institute for Brain Science, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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3
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Choi WJ, Li Y, Wang RK, Kim JK. Automated counting of cerebral penetrating vessels using optical coherence tomography images of a mouse brain in vivo. Med Phys 2022; 49:5225-5235. [PMID: 35616390 DOI: 10.1002/mp.15775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 05/17/2022] [Accepted: 05/17/2022] [Indexed: 11/08/2022] Open
Abstract
RATIONALE AND OBJECTIVES Penetrating blood vessels emanating from cortical surface vasculature and lying deep in the cortex are essential vascular conduits for the shuttling of blood from superficial pial vessels to the capillary beds in parenchyma for the nourishment of neuronal brain tissues. Locating and counting the penetrating vessels is beneficial for the quantification of a course of ischemia in blood occlusive events such as stroke. This paper seeks to demonstrate and validate a method for automated penetrating vessel counting that uses optical coherence tomography (OCT). MATERIALS AND METHODS This paper proposes an OCT method that effectively identifies and grades the cortical penetrating vessels in perfusion. The key to the proposed method is the harnessing of vascular features found in the penetrating vessels, which are distinctive from those of other vessels. In particular, with an increase in the light attenuation and flow turbulence, the contrast in the mean projection of the OCT datacube decreases, whereas that in the maximum projection of the Doppler frequency variance datacube increases. By multiplying the inversion of the former with the latter, its binary thresholding is sufficient to highlight the penetrating vessels and allows for their counting over the projection image. RESULTS A computational method that leverages the decrease in mean OCT projection intensity and the increase in Doppler frequency variance at the penetrating vessel is developed. It successfully identifies and counts penetrating vessels with a high accuracy of over 87%. The penetrating vessel density is observed to be significantly reduced in the mouse model of focal ischemic stroke. CONCLUSION The OCT analysis is effective for counting penetrating blood vessels in mice brains and may be applied to the rapid diagnosis and treatment of stroke in stroke models of small animals. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Woo June Choi
- School of Electrical and Electronics Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Korea
| | - Yuandong Li
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Jun Ki Kim
- Department of Convergence Medicine, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Seoul, 05505, Korea.,Asan Institute for Life Science, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea
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4
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Wu J, Wu N, Tang P, Lin J, Lian Y, Tang Z. Pulse photothermal optical coherence tomography for multimodal hemodynamic imaging. OPTICS LETTERS 2021; 46:5635-5638. [PMID: 34780424 DOI: 10.1364/ol.442552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
To realize multimodal hemodynamic imaging, pulse photothermal optical coherence tomography (P-PTOCT) is proposed in this Letter to solve the separation problem of photothermal phase and Doppler phase, which is difficult to solve in traditional PTOCT. This technique can obtain blood flow distribution, light absorption distribution, and concentration images simultaneously. Based on the difference between pulse photothermal phase and Doppler phase, we propose an even number differential demodulation algorithm that can separate the photothermal phase and Doppler phase from the same scanning data set. The separated photothermal phase can characterize the trend of drug concentration, which provides the possibility for quantitative measurement of plasma concentration. The combination of photothermal phase and Doppler phase is helpful for potential clinical research on hemodynamics of cerebral ischemia and provides a technical reference for the rapid acquisition of perfusion volume and plasma concentration at one time.
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Rakymzhan A, Li Y, Tang P, Wang RK. Differences in cerebral blood vasculature and flow in awake and anesthetized mouse cortex revealed by quantitative optical coherence tomography angiography. J Neurosci Methods 2021; 353:109094. [PMID: 33549637 DOI: 10.1016/j.jneumeth.2021.109094] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 01/27/2021] [Accepted: 01/31/2021] [Indexed: 12/25/2022]
Abstract
BACKGROUND Most of the in vivo neurovascular imaging studies are performed in anesthetized animals. However, anesthesia significantly affects cerebral hemodynamics. NEW METHOD We applied optical coherence tomography (OCT) methods such as optical microangiography (OMAG) and Doppler optical microangiography (DOMAG) to quantitatively evaluate the effect of anesthesia in cerebral vasculature and blood flow in mouse brain. RESULTS The OMAG results indicated the increase of large vessel diameter and capillary density induced by ketamine-xylazine and isoflurane, meaning that both anesthetics caused vasodilation. In addition, the preliminary results from DOMAG showed that isoflurane increased the baseline cerebral blood flow. COMPARISON WITH EXISTING METHODS In comparison with other in vivo imaging modalities, OCT can provide label-free assessment of cortical tissue including tissue morphology, cerebral blood vessel network and flow information down to capillary level, with a large field of view and high imaging speed. CONCLUSIONS OCT angiography methods demonstrated the ability to measure the differences in the baseline morphological and flow parameters of both large and capillary cerebrovascular networks between awake and anesthetized mice.
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Affiliation(s)
- Adiya Rakymzhan
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA
| | - Yuandong Li
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA
| | - Peijun Tang
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA.
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6
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Li Y, Rakymzhan A, Tang P, Wang RK. Procedure and protocols for optical imaging of cerebral blood flow and hemodynamics in awake mice. BIOMEDICAL OPTICS EXPRESS 2020; 11:3288-3300. [PMID: 32637255 PMCID: PMC7316002 DOI: 10.1364/boe.394649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/09/2020] [Accepted: 05/19/2020] [Indexed: 05/10/2023]
Abstract
We describe a method and procedure that allows for the optical coherence tomography angiography (OCTA) and intrinsic optical signal imaging (IOSI) of cerebral blood flow and hemodynamics in fully awake mice. We detail the procedure of chronic cranial window preparation, the use of an air-lift mobile homecage to achieve stable optical recording in the head-restrained awake mouse, and the imaging methods to achieve multiparametric hemodynamic measurements. The results show that by using a collection of OCTA algorithms, the high-resolution cerebral vasculature can be reliably mapped at a fully awake state, including flow velocity measurements in penetrating arterioles and capillary bed. Lastly, we demonstrate how the awake imaging paradigm is used to study cortical hemodynamics in the mouse barrel cortex during whisker stimulation. The method presented here will facilitate optical recording in the awake, active mice and open the door to many projects that can bridge the hemodynamics in neurovascular units to naturalistic behavior.
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7
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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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Choi WJ, Li Y, Wang RK. Monitoring Acute Stroke Progression: Multi-Parametric OCT Imaging of Cortical Perfusion, Flow, and Tissue Scattering in a Mouse Model of Permanent Focal Ischemia. IEEE TRANSACTIONS ON MEDICAL IMAGING 2019; 38:1427-1437. [PMID: 30714910 PMCID: PMC6660833 DOI: 10.1109/tmi.2019.2895779] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Cerebral ischemic stroke causes injury to brain tissue characterized by a complex cascade of neuronal and vascular events. Imaging during the early stages of its development allows prediction of tissue infarction and penumbra so that optimal intervention can be determined in order to salvage brain function impairment. Therefore, there is a critical need for novel imaging techniques that can characterize brain injury in the earliest phases of the ischemic stroke. This paper examined optical coherence tomography (OCT) for imaging acute injury in experimental ischemic stroke in vivo. Based on endogenous optical scattering signals provided by OCT imaging, we have developed a single, integrated imaging platform enabling the measurement of changes in blood perfusion, blood flow, erythrocyte velocity, and light attenuation within a cortical tissue, during focal cerebral ischemia in a mouse model. During the acute phase (from 5 min to the first few hours following the blood occlusion), the multi-parametric OCT imaging revealed multiple hemodynamic and tissue scattering responses in vivo, including cerebral blood flow deficits, capillary non-perfusion, displacement of penetrating vessels, and increased light attenuation in the cortical tissue at risk that are spatially correlated with the infarct core, as determined by postmortem staining with triphenyltetrazolium chloride. The use of multi-parametric OCT imaging may aid in the comprehensive evaluation of ischemic lesions during the early stages of stroke, thereby providing essential knowledge for guiding treatment decisions.
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Affiliation(s)
- Woo June Choi
- School of Electrical and Electronics Engineering, College of ICT Engineering, Chung-Ang University, Seoul, 06974, Korea
| | - Yuandong Li
- Department of Bioengineering, University of Washington, Seattle WA 98195, USA
| | - Ruikang K. Wang
- Corresponding author, phone: 206-616-5025; fax: 206-616-5025;
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9
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Li Y, Choi WJ, Wei W, Song S, Zhang Q, Liu J, Wang RK. Aging-associated changes in cerebral vasculature and blood flow as determined by quantitative optical coherence tomography angiography. Neurobiol Aging 2018; 70:148-159. [PMID: 30007164 DOI: 10.1016/j.neurobiolaging.2018.06.017] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 06/14/2018] [Accepted: 06/14/2018] [Indexed: 01/29/2023]
Abstract
Normal aging is associated with significant alterations in brain's vascular structure and function, which can lead to compromised cerebral circulation and increased risk of neurodegeneration. The in vivo examination of cerebral blood flow (CBF), including capillary beds, in aging brains with sufficient spatial detail remains challenging with current imaging modalities. In the present study, we use 3-dimensional (3-D) quantitative optical coherence tomography angiography (OCTA) to examine characteristic differences of the cerebral vasculatures and hemodynamics at the somatosensory cortex between old (16 months old) and young mice (2 months old) in vivo. The quantitative metrics include cortical vascular morphology, CBF, and capillary flow velocity. We show that compared with young mice, the pial arterial tortuosity increases by 14%, the capillary vessel density decreases by 15%, and the CBF reduces by 33% in the old mice. Most importantly, changes in capillary velocity and heterogeneity with aging are quantified for the first time with sufficiently high statistical power between young and old populations, with a 21% (p < 0.05) increase in capillary mean velocity and 19% (p ≤ 0.05) increase in velocity heterogeneity in the latter. Our findings through noninvasive imaging are in line with previous studies of vascular structure modification with aging, with additional quantitative assessment in capillary velocity enabled by advanced OCTA algorithms on a single imaging platform. The results offer OCTA as a promising neuroimaging tool to study vascular aging, which may shed new light on the investigations of vascular factors contributing to the pathophysiology of age-related neurodegenerative disorders.
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Affiliation(s)
- Yuandong Li
- Department of Bioengineering, College of Engineering and School of Medicine, University of Washington, Seattle, WA, USA
| | - Woo June Choi
- Department of Bioengineering, College of Engineering and School of Medicine, University of Washington, Seattle, WA, USA; School of Electrical and Electronics Engineering, College of ICT Engineering, Chung-Ang University, Seoul, Korea
| | - Wei Wei
- Department of Bioengineering, College of Engineering and School of Medicine, University of Washington, Seattle, WA, USA
| | - Shaozhen Song
- Department of Bioengineering, College of Engineering and School of Medicine, University of Washington, Seattle, WA, USA
| | - Qinqin Zhang
- Department of Bioengineering, College of Engineering and School of Medicine, University of Washington, Seattle, WA, USA
| | - Jialing Liu
- Department of Neurological Surgery, University of California, San Francisco and SFVAMC, San Francisco, CA, USA
| | - Ruikang K Wang
- Department of Bioengineering, College of Engineering and School of Medicine, University of Washington, Seattle, WA, USA.
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Park T, Jang SJ, Han M, Ryu S, Oh WY. Wide dynamic range high-speed three-dimensional quantitative OCT angiography with a hybrid-beam scan. OPTICS LETTERS 2018; 43:2237-2240. [PMID: 29762561 DOI: 10.1364/ol.43.002237] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We demonstrate a novel hybrid-beam scanning-based quantitative optical coherence tomography angiography (OCTA) that provides high-speed wide dynamic range blood flow speed imaging. The hybrid-beam scanning scheme enables multiple OCTA image acquisitions with a wide range of multiple time intervals simultaneously providing wide dynamic range blood flow speed imaging independent of the blood vessel orientation, which was quantified over a speed range of 0.6∼104 mm/s through the blood flow phantom experiments. A fully automated high-speed hybrid-beam scanning-based quantitative OCTA system demonstrates visualization of blood flow speeds in various vessels from the main arteries to capillaries in a 4 mm×4 mm area (1024 A-lines × 512 B-scans) in vivo in 20 s, showing its potential as a useful imaging tool for various biomedical applications.
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11
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Li Y, Wei W, Wang RK. Capillary flow homogenization during functional activation revealed by optical coherence tomography angiography based capillary velocimetry. Sci Rep 2018. [PMID: 29515156 PMCID: PMC5841298 DOI: 10.1038/s41598-018-22513-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Elaborate modeling study suggests an important role of capillary transit time heterogeneity (CTTH) reduction in brain oxygenation during functional hyperemia. Here, we use optical coherence tomography angiography (OCTA) capillary velocimetry to probe blood flow dynamics in cerebral capillary beds and validate the change in CTTH during functional activation in an in vivo rodent model. Through evaluating flow dynamics and consequent transit time parameters from thousands of capillary vessels within three-dimensional (3-D) tissue volume upon hindpaw electrical stimulation, we observe reductions in both capillary mean transit time (MTT) (9.8% ± 2.2) and CTTH (5.9% ± 1.4) in the hindlimb somatosensory cortex (HLS1). Additionally, capillary flow pattern modification is observed with a significant difference (p < 0.05) between the HLS1 and non-activated cortex regions. These quantitative findings reveal a localized microcirculatory adjustment during functional activation, consistent with previous studies, and support the critical contribution of capillary flow homogenization to brain oxygenation. The OCTA velocimetry is a useful tool to image microcirculatory dynamics in vivo using animal models, enabling a more comprehensive understanding as to hemodynamic-metabolic coupling.
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Affiliation(s)
- Yuandong Li
- Department of Bioengineering, University of Washington, Seattle, USA
| | - Wei Wei
- Department of Bioengineering, University of Washington, Seattle, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, USA.
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12
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Chu Z, Chen CL, Zhang Q, Pepple K, Durbin M, Gregori G, Wang RK. Complex signal-based optical coherence tomography angiography enables in vivo visualization of choriocapillaris in human choroid. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-10. [PMID: 29178697 PMCID: PMC5745879 DOI: 10.1117/1.jbo.22.12.121705] [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: 08/04/2017] [Accepted: 11/08/2017] [Indexed: 05/15/2023]
Abstract
The choriocapillaris (CC) plays an essential role in maintaining the normal functions of the human eye. There is increasing interest in the community to develop an imaging technique for visualizing the CC, yet this remains underexplored due to technical limitations. We propose an approach for the visualization of the CC in humans via a complex signal-based optical microangiography (OMAG) algorithm, based on commercially available spectral domain optical coherence tomography (SD-OCT). We show that the complex signal-based OMAG was superior to both the phase and amplitude signal-based approaches in detailing the vascular lobules previously seen with histological analysis. With this improved ability to visualize the lobular vascular networks, it is possible to identify the feeding arterioles and draining venules around the lobules, which is important in understanding the role of the CC in the pathogenesis of ocular diseases. With built-in FastTrac™ and montage scanning capabilities, we also demonstrate wide-field SD-OCT angiograms of the CC with a field of view at 9×11 mm2.
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Affiliation(s)
- Zhongdi Chu
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Chieh-Li Chen
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Qinqin Zhang
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Kathryn Pepple
- University of Washington, Department of Ophthalmology, Seattle, Washington, United States
| | - Mary Durbin
- Carl Zeiss Meditec, Inc., Advanced Development, Dublin, California, United States
| | - Giovanni Gregori
- University of Miami Miller School of Medicine, Bascom Palmer Eye Institute, Department of Ophthalmology, Miami, Florida, United States
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
- University of Washington, Department of Ophthalmology, Seattle, Washington, United States
- Address all correspondence to: Ruikang K. Wang, E-mail:
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Tang J, Erdener SE, Fu B, Boas DA. Capillary red blood cell velocimetry by phase-resolved optical coherence tomography. OPTICS LETTERS 2017; 42:3976-3979. [PMID: 28957175 PMCID: PMC5972360 DOI: 10.1364/ol.42.003976] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 09/05/2017] [Indexed: 05/05/2023]
Abstract
We present a phase-resolved optical coherence tomography (OCT) method to extend Doppler OCT for the accurate measurement of the red blood cell (RBC) velocity in cerebral capillaries. OCT data were acquired with an M-mode scanning strategy (repeated A-scans) to account for the single-file passage of RBCs in a capillary, which were then high-pass filtered to remove the stationary component of the signal to ensure an accurate measurement of phase shift of flowing RBCs. The angular frequency of the signal from flowing RBCs was then quantified from the dynamic component of the signal and used to calculate the axial speed of flowing RBCs in capillaries. We validated our measurement by RBC passage velocimetry using the signal magnitude of the same OCT time series data.
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Affiliation(s)
- Jianbo Tang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Sefik Evren Erdener
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Buyin Fu
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - David A. Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
- Neurophotonics Center, Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
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14
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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: 270] [Impact Index Per Article: 38.6] [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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15
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Xu J, Song S, Wei W, Wang RK. Wide field and highly sensitive angiography based on optical coherence tomography with akinetic swept source. BIOMEDICAL OPTICS EXPRESS 2017; 8:420-435. [PMID: 28101428 PMCID: PMC5231310 DOI: 10.1364/boe.8.000420] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/15/2016] [Accepted: 12/18/2016] [Indexed: 05/03/2023]
Abstract
Wide-field vascular visualization in bulk tissue that is of uneven surface is challenging due to the relatively short ranging distance and significant sensitivity fall-off for most current optical coherence tomography angiography (OCTA) systems. We report a long ranging and ultra-wide-field OCTA (UW-OCTA) system based on an akinetic swept laser. The narrow instantaneous linewidth of the swept source with its high phase stability, combined with high-speed detection in the system enable us to achieve long ranging (up to 46 mm) and almost negligible system sensitivity fall-off. To illustrate these advantages, we compare the basic system performances between conventional spectral domain OCTA and UW-OCTA systems and their functional imaging of microvascular networks in living tissues. In addition, we show that the UW-OCTA is capable of different depth-ranging of cerebral blood flow within entire brain in mice, and providing unprecedented blood perfusion map of human finger in vivo. We believe that the UW-OCTA system has promises to augment the existing clinical practice and explore new biomedical applications for OCT imaging.
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16
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Nishijima Y, Akamatsu Y, Yang SY, Lee CC, Baran U, Song S, Wang RK, Tominaga T, Liu J. Impaired Collateral Flow Compensation During Chronic Cerebral Hypoperfusion in the Type 2 Diabetic Mice. Stroke 2016; 47:3014-3021. [PMID: 27834741 DOI: 10.1161/strokeaha.116.014882] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/03/2016] [Accepted: 09/14/2016] [Indexed: 01/30/2023]
Abstract
BACKGROUND AND PURPOSE The presence of collaterals is associated with a reduced risk of stroke and transient ischemic attack in patients with steno-occlusive carotid artery disease. Although metabolic syndrome negatively impacts collateral status, it is unclear whether and to what extent type 2 diabetes mellitus affects cerebral collateral flow regulation during hypoperfusion. METHODS We examined the spatial and temporal changes of the leptomeningeal collateral flow and the flow dynamics of the penetrating arterioles in the distal middle cerebral artery and anterior cerebral artery branches over 2 weeks after unilateral common carotid artery occlusion (CCAO) using optical coherent tomography in db/+ and db/db mice. We also assessed the temporal adaptation of the circle of Willis after CCAO by measuring circle of Willis vessel diameters. RESULTS After unilateral CCAO, db/db mice exhibited diminished leptomeningeal collateral flow compensation compared with db/+ mice, which coincided with a reduced dilation of distal anterior cerebral artery branches, leading to reduced flow not only in pial vessels but also in penetrating arterioles bordering the distal middle cerebral artery and anterior cerebral artery. However, no apparent cell death was detected in either strain of mice during the first week after CCAO. db/db mice also experienced a more severe early reduction in the vessel diameters of several ipsilateral main feeding arteries in the circle of Willis, in addition to a delayed post-CCAO adaptive response by 1 to 2 weeks, compared with db/+ mice. CONCLUSIONS Type 2 diabetes mellitus is an additional risk factor for hemodynamic compromise during cerebral hypoperfusion, which may increase the severity and the risk of stroke or transient ischemic attack.
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Affiliation(s)
- Yasuo Nishijima
- Department of Neurological Surgery, University of California at San Francisco (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); San Francisco Veterans Affairs Medical Center, CA (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); Department of Neurosurgery, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan (Y.N., Y.A., T.T.); and Departments of Bioengineering & Ophthalmology, University of Washington, Seattle (U.B., S.S., R.K.W.)
| | - Yosuke Akamatsu
- Department of Neurological Surgery, University of California at San Francisco (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); San Francisco Veterans Affairs Medical Center, CA (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); Department of Neurosurgery, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan (Y.N., Y.A., T.T.); and Departments of Bioengineering & Ophthalmology, University of Washington, Seattle (U.B., S.S., R.K.W.)
| | - Shih Yen Yang
- Department of Neurological Surgery, University of California at San Francisco (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); San Francisco Veterans Affairs Medical Center, CA (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); Department of Neurosurgery, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan (Y.N., Y.A., T.T.); and Departments of Bioengineering & Ophthalmology, University of Washington, Seattle (U.B., S.S., R.K.W.)
| | - Chih Cheng Lee
- Department of Neurological Surgery, University of California at San Francisco (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); San Francisco Veterans Affairs Medical Center, CA (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); Department of Neurosurgery, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan (Y.N., Y.A., T.T.); and Departments of Bioengineering & Ophthalmology, University of Washington, Seattle (U.B., S.S., R.K.W.)
| | - Utku Baran
- Department of Neurological Surgery, University of California at San Francisco (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); San Francisco Veterans Affairs Medical Center, CA (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); Department of Neurosurgery, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan (Y.N., Y.A., T.T.); and Departments of Bioengineering & Ophthalmology, University of Washington, Seattle (U.B., S.S., R.K.W.)
| | - Shaozhen Song
- Department of Neurological Surgery, University of California at San Francisco (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); San Francisco Veterans Affairs Medical Center, CA (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); Department of Neurosurgery, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan (Y.N., Y.A., T.T.); and Departments of Bioengineering & Ophthalmology, University of Washington, Seattle (U.B., S.S., R.K.W.)
| | - Ruikang K Wang
- Department of Neurological Surgery, University of California at San Francisco (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); San Francisco Veterans Affairs Medical Center, CA (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); Department of Neurosurgery, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan (Y.N., Y.A., T.T.); and Departments of Bioengineering & Ophthalmology, University of Washington, Seattle (U.B., S.S., R.K.W.)
| | - Teiji Tominaga
- Department of Neurological Surgery, University of California at San Francisco (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); San Francisco Veterans Affairs Medical Center, CA (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); Department of Neurosurgery, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan (Y.N., Y.A., T.T.); and Departments of Bioengineering & Ophthalmology, University of Washington, Seattle (U.B., S.S., R.K.W.)
| | - Jialing Liu
- Department of Neurological Surgery, University of California at San Francisco (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); San Francisco Veterans Affairs Medical Center, CA (Y.N., Y.A., S.Y.Y., C.C.L., J.L.); Department of Neurosurgery, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan (Y.N., Y.A., T.T.); and Departments of Bioengineering & Ophthalmology, University of Washington, Seattle (U.B., S.S., R.K.W.).
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17
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Li Y, Choi WJ, Qin W, Baran U, Habenicht LM, Wang RK. Optical coherence tomography based microangiography provides an ability to longitudinally image arteriogenesis in vivo. J Neurosci Methods 2016; 274:164-171. [PMID: 27751893 DOI: 10.1016/j.jneumeth.2016.10.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 10/11/2016] [Accepted: 10/13/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND Arteriogenesis describes the active growth of the pre-existing collateral arterioles, which is a crucial tissue-saving process in occlusive vascular diseases. NEW METHOD We propose to use optical coherence tomography (OCT)-based microangiography (OMAG) to monitor arteriogenesis following artery transection in mouse ear and focal stroke in mouse brain. RESULTS Our longitudinal mouse ear study shows that the growth phase of arteriogenesis, indicated by changes in collateral vessel diameter and velocity, occurs between 12 and 24h after vessel transection. Additionally, the magnitude of local inflammation is consistent with the time course of arteriogenesis, judging by the tissue thickness measurement and lymphatic vessel signals in OCT. In the mouse brain study, collateral vessel morphology, blood flow velocity and directionality are identified, and an activation of the collateral flow at the arteriolo-arteriolar anastomoses (AAA) is observed during stroke. COMPARISON WITH EXISTING METHODS In comparison with histology and fluorescence imaging, OCT/OMAG is completely non-invasive and capable of producing consistent results of longitudinal changes in collateral vessel morphology and vasodynamics. CONCLUSION OCT/OMAG is a promising imaging tool for longitudinal study of collateral vessel remodeling in small animals. This technique can be applied in guiding the in vivo experiments of arteriogenesis stimulation to treat occlusive vascular diseases, including stroke.
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Affiliation(s)
- Yuandong Li
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Woo June Choi
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Wan Qin
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Utku Baran
- Department of Bioengineering, University of Washington, Seattle, WA, USA; Department of Electrical Engineering, University of Washington, Seattle, WA, USA
| | - Lauren M Habenicht
- Department of Comparative Medicine, University of Washington, Seattle, WA, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA.
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18
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Lal C, Leahy MJ. An Updated Review of Methods and Advancements in Microvascular Blood Flow Imaging. Microcirculation 2016; 23:345-63. [DOI: 10.1111/micc.12284] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Accepted: 04/17/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Cerine Lal
- Department of Applied Physics; Tissue Optics and Microcirculation Imaging; National University of Ireland; Galway Ireland
| | - Martin J Leahy
- Department of Applied Physics; Tissue Optics and Microcirculation Imaging; National University of Ireland; Galway Ireland
- Royal College of Surgeons in Ireland; Dublin Ireland
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19
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Choi WJ, Qin W, Chen CL, Wang J, Zhang Q, Yang X, Gao BZ, Wang RK. Characterizing relationship between optical microangiography signals and capillary flow using microfluidic channels. BIOMEDICAL OPTICS EXPRESS 2016; 7:2709-28. [PMID: 27446700 PMCID: PMC4948624 DOI: 10.1364/boe.7.002709] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 06/15/2016] [Accepted: 06/15/2016] [Indexed: 05/17/2023]
Abstract
Optical microangiography (OMAG) is a powerful optical angio-graphic tool to visualize micro-vascular flow in vivo. Despite numerous demonstrations for the past several years of the qualitative relationship between OMAG and flow, no convincing quantitative relationship has been proven. In this paper, we attempt to quantitatively correlate the OMAG signal with flow. Specifically, we develop a simplified analytical model of the complex OMAG, suggesting that the OMAG signal is a product of the number of particles in an imaging voxel and the decorrelation of OCT (optical coherence tomography) signal, determined by flow velocity, inter-frame time interval, and wavelength of the light source. Numerical simulation with the proposed model reveals that if the OCT amplitudes are correlated, the OMAG signal is related to a total number of particles across the imaging voxel cross-section per unit time (flux); otherwise it would be saturated but its strength is proportional to the number of particles in the imaging voxel (concentration). The relationship is validated using microfluidic flow phantoms with various preset flow metrics. This work suggests OMAG is a promising quantitative tool for the assessment of vascular flow.
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Affiliation(s)
- Woo June Choi
- Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA
- These authors contributed equally to this work
| | - Wan Qin
- Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA
- These authors contributed equally to this work
| | - Chieh-Li Chen
- Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA
| | - Jingang Wang
- Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA
| | - Xiaoqi Yang
- Department of Bioengineering and COMSET, Clemson University, Clemson, SC 29634, USA
| | - Bruce Z. Gao
- Department of Bioengineering and COMSET, Clemson University, Clemson, SC 29634, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA
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20
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Atry F, Pashaie R. Analysis of intermediary scan-lens and tube-lens mechanisms for optical coherence tomography. APPLIED OPTICS 2016; 55:646-53. [PMID: 26836064 DOI: 10.1364/ao.55.000646] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Combining an optical coherence tomography (OCT) scanner with other techniques such as optogenetic neurostimulation or fluorescence imaging requires integrating auxiliary components into the optical path of the setup. Due to the short scanning distance of most OCT objectives, adding scan and tube lenses in the device is essential to open space between the back-focal-plane of the objective and center of mass of the mirrors in the galvanometer. The effect of the scan and tube lenses on the focal spot size of the scanner using off-the-shelf components are theoretically explored for three different designs in this paper. Two lens mechanisms were implemented and tested in a custom-built OCT scanner to experimentally measure point-spread functions. Based on our analysis, proper form of a four-element semi-Plössl lens provides a superior performance compared with an achromatic doublet when used as a scan/tube lens. The former lens design provides close to diffraction-limited resolution for scan angles up to 6.4°; however, due to aberrations in an achromatic doublet, the later design offers diffraction-limited resolution confined to 2° scan angles.
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21
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Baran U, Wang RK. Review of optical coherence tomography based angiography in neuroscience. NEUROPHOTONICS 2016; 3:010902. [PMID: 26835484 PMCID: PMC4719095 DOI: 10.1117/1.nph.3.1.010902] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 12/14/2015] [Indexed: 05/09/2023]
Abstract
The brain is a complex ecosystem, consisting of multiple layers and tissue compartments. To facilitate the understanding of its function and its response to neurological insults, a fast in vivo imaging tool with a micron-level resolution, which can provide a field of view at a few millimeters, is desirable. Optical coherence tomography (OCT) is a noninvasive method for imaging three-dimensional biological tissues with high resolution ([Formula: see text]) and without a need for contrast agents. Recent development of OCT-based angiography has started to shed some new light on cerebral hemodynamics in neuroscience. We give an overview of the recent developments of OCT-based imaging techniques for neuroscience applications in rodents. We summarize today's technological alternatives for OCT-based angiography for neuroscience and provide a discussion of challenges and opportunities. Moreover, a summary of OCT angiography studies for stroke, traumatic brain injury, and subarachnoid hemorrhage cases on rodents is provided.
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Affiliation(s)
- 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
| | - 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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22
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Baran U, Li Y, Wang RK. In vivo tissue injury mapping using optical coherence tomography based methods. APPLIED OPTICS 2015; 54:6448-53. [PMID: 26367827 PMCID: PMC4570269 DOI: 10.1364/ao.54.006448] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
An injury causes changes in the optical attenuation coefficient (OAC) of a light beam traveling inside a tissue. We report a method called tissue injury mapping (TIM), which utilizes a noninvasive in vivo optical coherence tomography approach to generate an OAC and microvascular map of the injured tissue. Using TIM, the infarct region development in a mouse cerebral cortex during a stroke is visualized. Moreover, we demonstrate the changes in human facial skin structure and microvasculature during an acne lesion development from initiation to scarring. The results indicate that TIM may be used to aid in the characterization and the treatment of various diseases by enabling a high-resolution detection of tissue structural and microvascular changes.
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Affiliation(s)
- Utku Baran
- Dept. of Bioengineering, University of Washington, 3720 15th Ave. NE, Seattle WA 98195, USA
- Dept. of Electrical Engineering, University of Washington, 185 Stevens Way, Seattle WA 98195, USA
| | - Yuandong Li
- Dept. of Bioengineering, University of Washington, 3720 15th Ave. NE, Seattle WA 98195, USA
| | - Ruikang K. Wang
- Dept. of Bioengineering, University of Washington, 3720 15th Ave. NE, Seattle WA 98195, USA
- Corresponding author:
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23
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Dziennis S, Qin J, Shi L, Wang RK. Macro-to-micro cortical vascular imaging underlies regional differences in ischemic brain. Sci Rep 2015; 5:10051. [PMID: 25941797 PMCID: PMC4419594 DOI: 10.1038/srep10051] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 03/19/2015] [Indexed: 01/05/2023] Open
Abstract
The ability to non-invasively monitor and quantify hemodynamic responses down to the capillary level is important for improved diagnosis, treatment and management of neurovascular disorders, including stroke. We developed an integrated multi-functional imaging system, in which synchronized dual wavelength laser speckle contrast imaging (DWLS) was used as a guiding tool for optical microangiography (OMAG) to test whether detailed vascular responses to experimental stroke in male mice can be evaluated with wide range sensitivity from arteries and veins down to the capillary level. DWLS enabled rapid identification of cerebral blood flow (CBF), prediction of infarct area and hemoglobin oxygenation over the whole mouse brain and was used to guide the OMAG system to hone in on depth information regarding blood volume, blood flow velocity and direction, vascular architecture, vessel diameter and capillary density pertaining to defined regions of CBF in response to ischemia. OMAG-DWLS is a novel imaging platform technology to simultaneously evaluate multiple vascular responses to ischemic injury, which can be useful in improving our understanding of vascular responses under pathologic and physiological conditions, and ultimately facilitating clinical diagnosis, monitoring and therapeutic interventions of neurovascular diseases.
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Affiliation(s)
- Suzan Dziennis
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Jia Qin
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Lei Shi
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
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24
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Baran U, Li Y, Wang RK. Vasodynamics of pial and penetrating arterioles in relation to arteriolo-arteriolar anastomosis after focal stroke. NEUROPHOTONICS 2015; 2:025006. [PMID: 26158010 PMCID: PMC4478965 DOI: 10.1117/1.nph.2.2.025006] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 05/18/2015] [Indexed: 05/18/2023]
Abstract
Changes in blood perfusion in highly interconnected pial arterioles provide important insights about the vascular response to ischemia within brain. The functional role of arteriolo-arteriolar anastomosis (AAA) in regulating blood perfusion through penetrating arterioles is yet to be discovered. We apply a label-free optical microangiography (OMAG) technique to evaluate the changes in vessel lumen diameter and red blood cell velocity among a large number of pial and penetrating arterioles within AAA abundant region overlaying the penumbra in the parietal cortex after a middle cerebral artery occlusion (MCAO). In comparison with two-photon microscopy, the OMAG technique makes it possible to image a large number of vessels in a short period of time without administering exogenous contrast agents during a time-constrained MCAO experiment. We compare vasodynamics in penetrating arterioles at various locations. The results show that the MCA connected penetrating arterioles close to a strong AAA dilate, while those belonging to a region away from AAAs constrict in various degrees. These results suggest AAAs play a major role in supporting the active dilation of the penetrating arterioles, thus compensating a significant amount of blood to the ischemic region, whereas the poor blood perfusion occurs at the regions away from AAA connections, leading to ischemia.
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Affiliation(s)
- Utku Baran
- University of Washington, Department of Bioengineering, 3720 NE 15th Avenue, Seattle, Washington 98195, United States
- University of Washington, Department of Electrical Engineering, 185 Stevens Way, Seattle, Washington 98195, United States
| | - Yuandong Li
- University of Washington, Department of Bioengineering, 3720 NE 15th Avenue, Seattle, Washington 98195, United States
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, 3720 NE 15th Avenue, Seattle, Washington 98195, United States
- Address all correspondence to: Ruikang K. Wang, E-mail:
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25
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Wang H, Baran U, Wang RK. In vivo blood flow imaging of inflammatory human skin induced by tape stripping using optical microangiography. JOURNAL OF BIOPHOTONICS 2015; 8:265-72. [PMID: 24659511 PMCID: PMC4308563 DOI: 10.1002/jbio.201400012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 02/25/2014] [Accepted: 02/27/2014] [Indexed: 05/03/2023]
Abstract
Vasculature response is a hallmark for most inflammatory skin disorders. Tape stripping on human skin causes a minor inflammation which leads to changes in microvasculature. In this study, optical microangiography (OMAG), noninvasive volumetric microvasculature in vivo imaging method, has been used to track the vascular responses after tape stripping. Vessel density has been quantified and used to correlate with the degree of skin irritation. The proved capability of OMAG technique in visualizing the microvasculature network under inflamed skin condition can play an important role in clinical trials of treatment and diagnosis of inflammatory skin disorders.
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Affiliation(s)
- Hequn Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Utku Baran
- Department of Electrical Engineering, University of Washington, Seattle, WA, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Electrical Engineering, University of Washington, Seattle, WA, USA
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26
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Li Y, Baran U, Wang RK. Application of thinned-skull cranial window to mouse cerebral blood flow imaging using optical microangiography. PLoS One 2014; 9:e113658. [PMID: 25426632 PMCID: PMC4245213 DOI: 10.1371/journal.pone.0113658] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 10/02/2014] [Indexed: 11/26/2022] Open
Abstract
In vivo imaging of mouse brain vasculature typically requires applying skull window opening techniques: open-skull cranial window or thinned-skull cranial window. We report non-invasive 3D in vivo cerebral blood flow imaging of C57/BL mouse by the use of ultra-high sensitive optical microangiography (UHS-OMAG) and Doppler optical microangiography (DOMAG) techniques to evaluate two cranial window types based on their procedures and ability to visualize surface pial vessel dynamics. Application of the thinned-skull technique is found to be effective in achieving high quality images for pial vessels for short-term imaging, and has advantages over the open-skull technique in available imaging area, surgical efficiency, and cerebral environment preservation. In summary, thinned-skull cranial window serves as a promising tool in studying hemodynamics in pial microvasculature using OMAG or other OCT blood flow imaging modalities.
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Affiliation(s)
- Yuandong Li
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
| | - Utku Baran
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
- Department of Electrical Engineering, University of Washington, Seattle, Washington, United States of America
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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27
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Yousefi S, Wang RK. Simultaneous estimation of bidirectional particle flow and relative flux using MUSIC-OCT: phantom studies. Phys Med Biol 2014; 59:6693-708. [PMID: 25327449 PMCID: PMC4220784 DOI: 10.1088/0031-9155/59/22/6693] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In an optical coherence tomography (OCT) scan from a living tissue, red blood cells (RBCs) are the major source of backscattering signal from moving particles within microcirculatory system. Measuring the concentration and velocity of RBC particles allows assessment of RBC flux and flow, respectively, to assess tissue perfusion and oxygen/nutrition exchange rates within micro-structures. In this paper, we propose utilizing spectral estimation techniques to simultaneously quantify bi-directional particle flow and relative flux by spectral estimation of the received OCT signal from moving particles within capillary tubes embedded in tissue mimicking phantoms. The proposed method can be directly utilized for in vivo quantification of capillaries and microvessels. Compared to the existing methods in the literature that can either quantify flow direction or power, our proposed method allows simultaneous flow (velocity) direction and relative flux (power) estimation.
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Affiliation(s)
- Siavash Yousefi
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
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28
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Wang H, Shi L, Qin J, Yousefi S, Li Y, Wang RK. Multimodal optical imaging can reveal changes in microcirculation and tissue oxygenation during skin wound healing. Lasers Surg Med 2014; 46:470-8. [PMID: 24788236 DOI: 10.1002/lsm.22254] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2014] [Indexed: 11/10/2022]
Abstract
BACKGROUND AND OBJECTIVE Faster and better wound healing is a longstanding goal. Blood flow, angiogenesis, and tissue oxygenation are important parameters in evaluating the healing process. Optical microangiography (OMAG) allows 3D imaging of tissue vasculature and can provide quantitative blood flow information down to the capillary level of resolution. Dual wavelength laser speckle imaging (DW-LSI) can measure tissue oxygenation status. MATERIALS AND METHODS Cutaneous wound healing of a mouse ear model using a multimodal imaging system that combines OMAG with DWLSI was studied. RESULTS A complete microvasculature map of the ear in vivo was obtained. The imaging system revealed both hemodynamic and metabolic changes during acute stage wound healing. Blood flow velocity, blood flow direction, as well as changes in concentration of oxygenated hemoglobin (ΔHbO) and deoxygenated hemoglobin (ΔHb) were measured and quantified. In addition, capillary recruitment and angiogenesis were visualized during the chronic stage of repairing. CONCLUSIONS The combination of DW-LSI and OMAG imaging technique may be a powerful tool to visualize and understand microvascular, hemodynamic, and metabolic changes during cutaneous wound healing.
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Affiliation(s)
- Hequn Wang
- Department of Bioengineering, University of Washington, Seattle, Washington
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29
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Abstract
We report on the functional optical coherence tomography (OCT) imaging of iris tissue morphology and microcirculation in living small animals. Anterior segments of healthy mouse and rat eyes are imaged with high-speed spectral domain OCT (SD-OCT) utilizing ultrahigh sensitive optical microangiography (UHS-OMAG) imaging protocol. 3D iris microvasculature is produced by the use of an algorithm that calculates absolute differences between the amplitudes of the OCT interframes. We demonstrate that the UHS-OMAG is capable of delineating iris microvascular beds in the mouse and rat with capillary-level resolution. Furthermore, the fast imaging speed enables dynamic imaging of iris micro-vascular response during drug-induced pupil dilation. We believe that this OCT angiographic approach has a great potential for in situ and in vivo monitoring of the microcirculation within iris tissue beds in rodent disease models that have microvascular involvement.
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Affiliation(s)
- Woo June Choi
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Zhongwei Zhi
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
- Department of Ophthalmology, University of Washington, Seattle, Washington 98195, USA
- Corresponding author:
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30
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Choi WJ, Wang RK. Volumetric cutaneous microangiography of human skin in vivo by VCSEL swept-source optical coherence tomography. QUANTUM ELECTRONICS 2014; 44:740. [PMID: 25635163 PMCID: PMC4307845 DOI: 10.1070/qe2014v044n08abeh015542] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Three-dimensional (3D) assessment of cutaneous microcirculation in human skin is essential in the identification of disease states in skin or other organs. Few 3D imaging techniques have revealed the skin micro-vasculatures non-invasively and with sufficient imaging depth. Here, we demonstrate volumetric cutaneous microangiography of the human skin in vivo that utilizes a 1.3 µm high-speed swept-source optical coherence tomography (SS-OCT). The swept source is based on a MEMS tunable vertical cavity surface emission laser (VCSEL) that is advantageous in terms of long coherence length over 50 mm and 100 nm spectral bandwidth that enables the visualization of microstructures within a few mm from the skin surface. We show that skin microvasculature can be delineated in 3D SS-OCT images using ultrahigh-sensitive optical microangiography (UHS-OMAG) with a correlation mapping mask, providing a contrast enhanced blood perfusion map with capillary flow sensitivity. 3D microangiograms of a healthy human finger are shown with distinct cutaneous vessel architectures from different dermal layers and even within hypodermis. These findings suggest that the OCT microangiography could be a beneficial biomedical assay to assess cutaneous vascular functions in clinic.
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Affiliation(s)
| | - Ruikang K. Wang
- Address all correspondence to: Ruikang K. Wang, University of Washington, Department of Bioengineering, Seattle, Washington 98195; Tel: +1 206-616-5025; Fax: +1 206-685-3300;
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31
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Yousefi S, Qin J, Dziennis S, Wang RK. Assessment of microcirculation dynamics during cutaneous wound healing phases in vivo using optical microangiography. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:76015. [PMID: 25036212 PMCID: PMC4103582 DOI: 10.1117/1.jbo.19.7.076015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 05/24/2014] [Accepted: 06/05/2014] [Indexed: 05/20/2023]
Abstract
Cutaneous wound healing consists of multiple overlapping phases starting with blood coagulation following incision of blood vessels. We utilized label-free optical coherence tomography and optical microangiography (OMAG) to noninvasively monitor healing process and dynamics of microcirculation system in a mouse ear pinna wound model. Mouse ear pinna is composed of two layers of skin separated by a layer of cartilage and because its total thickness is around 500 μm, it can be utilized as an ideal model for optical imaging techniques. These skin layers are identical to human skin structure except for sweat ducts and glands. Microcirculatory system responds to the wound injury by recruiting collateral vessels to supply blood flow to hypoxic region. During the inflammatory phase, lymphatic vessels play an important role in the immune response of the tissue and clearing waste from interstitial fluid. In the final phase of wound healing, tissue maturation, and remodeling, the wound area is fully closed while blood vessels mature to support the tissue cells. We show that using OMAG technology allows noninvasive and label-free monitoring and imaging each phase of wound healing that can be used to replace invasive tissue sample histology and immunochemistry technologies.
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Affiliation(s)
- Siavash Yousefi
- University of Washington, Department of Bioengineering, Seattle, Washington 98195, United States
| | - Jia Qin
- University of Washington, Department of Bioengineering, Seattle, Washington 98195, United States
| | - Suzan Dziennis
- 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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