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Zheng T, Liversage AR, Tehrani KF, Call JA, Kner PA, Mortensen LJ. Imaging mitochondria through bone in live mice using two-photon fluorescence microscopy with adaptive optics. FRONTIERS IN NEUROIMAGING 2023; 2:959601. [PMID: 37554651 PMCID: PMC10406258 DOI: 10.3389/fnimg.2023.959601] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 01/09/2023] [Indexed: 08/10/2023]
Abstract
INTRODUCTION Mitochondria are extremely important organelles in the regulation of bone marrow and brain activity. However, live imaging of these subcellular features with high resolution in scattering tissues like brain or bone has proven challenging. METHODS In this study, we developed a two-photon fluorescence microscope with adaptive optics (TPFM-AO) for high-resolution imaging, which uses a home-built Shack-Hartmann wavefront sensor (SHWFS) to correct system aberrations and a sensorless approach for correcting low order tissue aberrations. RESULTS Using AO increases the fluorescence intensity of the point spread function (PSF) and achieves fast imaging of subcellular organelles with 400 nm resolution through 85 μm of highly scattering tissue. We achieved ~1.55×, ~3.58×, and ~1.77× intensity increases using AO, and a reduction of the PSF width by ~0.83×, ~0.74×, and ~0.9× at the depths of 0, 50 μm and 85 μm in living mouse bone marrow respectively, allowing us to characterize mitochondrial health and the survival of functioning cells with a field of view of 67.5× 67.5 μm. We also investigate the role of initial signal and background levels in sample correction quality by varying the laser power and camera exposure time and develop an intensity-based criteria for sample correction. DISCUSSION This study demonstrates a promising tool for imaging of mitochondria and other organelles in optically distorting biological environments, which could facilitate the study of a variety of diseases connected to mitochondrial morphology and activity in a range of biological tissues.
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Affiliation(s)
- Tianyi Zheng
- School of Electrical and Computer Engineering, University of Georgia, Athens, GA, United States
| | - Adrian R. Liversage
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA, United States
| | - Kayvan F. Tehrani
- Biophotonics Imaging Laboratory, The University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Jarrod A. Call
- Department of Physiology and Pharmacology, University of Georgia, Athens, GA, United States
| | - Peter A. Kner
- School of Electrical and Computer Engineering, University of Georgia, Athens, GA, United States
| | - Luke J. Mortensen
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA, United States
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA, United States
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Durand M, Chateau A, Jubréaux J, Devy J, Paquot H, Laurent G, Bazzi R, Roux S, Richet N, Reinhard-Ruch A, Chastagner P, Pinel S. Radiosensitization with Gadolinium Chelate-Coated Gold Nanoparticles Prevents Aggressiveness and Invasiveness in Glioblastoma. Int J Nanomedicine 2023; 18:243-261. [PMID: 36660336 PMCID: PMC9844821 DOI: 10.2147/ijn.s375918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 11/23/2022] [Indexed: 01/15/2023] Open
Abstract
Purpose This study aimed to evaluate the radiosensitizing potential of Au@DTDTPA(Gd) nanoparticles when combined with conventional external X-ray irradiation (RT) to treat GBM. Methods Complementary biological models based on U87 spheroids including conventional 3D invasion assay, organotypic brain slice cultures, chronic cranial window model were implemented to investigate the impact of RT treatments (10 Gy single dose; 5×2 Gy or 2×5 Gy) combined with Au@DTDTPA(Gd) nanoparticles on tumor progression. The main tumor mass and its infiltrative area were analyzed. This work focused on the invading cancer cells after irradiation and their viability, aggressiveness, and recurrence potential were assessed using mitotic catastrophe quantification, MMP secretion analysis and neurosphere assays, respectively. Results In vitro clonogenic assays showed that Au@DTDTPA(Gd) nanoparticles exerted a radiosensitizing effect on U87 cells, and in vivo experiments suggested a benefit of the combined treatment "RT 2×5 Gy + Au@DTDTPA(Gd)" compared to RT alone. Invasion assays revealed that invasion distance tended to increase after irradiation alone, while the combined treatments were able to significantly reduce tumor invasion. Monitoring of U87-GFP tumor progression using organotypic cultures or intracerebral grafts confirmed the anti-invasive effect of Au@DTDTPA(Gd) on irradiated spheroids. Most importantly, the combination of Au@DTDTPA(Gd) with irradiation drastically reduced the number, the viability and the aggressiveness of tumor cells able to escape from U87 spheroids. Notably, the combined treatments significantly reduced the proportion of escaped cells with stem-like features that could cause recurrence. Conclusion Combining Au@DTDTPA(Gd) nanoparticles and X-ray radiotherapy appears as an attractive therapeutic strategy to decrease number, viability and aggressiveness of tumor cells that escape and can invade the surrounding brain parenchyma. Hence, Au@DTDTPA(Gd)-enhanced radiotherapy opens up interesting perspectives for glioblastoma treatment.
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Affiliation(s)
- Maxime Durand
- Université de Lorraine, CNRS, CRAN, Nancy, F-54000, France
| | - Alicia Chateau
- Université de Lorraine, CNRS, CRAN, Nancy, F-54000, France
| | | | - Jérôme Devy
- Université de Reims-Champagne-Ardennes, UMR CNRS/URCA 7369, MEDyC, Reims, F-51100, France
| | - Héna Paquot
- Université de Lorraine, CNRS, CRAN, Nancy, F-54000, France
| | - Gautier Laurent
- Université Bourgogne Franche-Comté, UMR 6213 CNRS-UBFC, UTINAM, Besançon, F-25000, France
| | - Rana Bazzi
- Université Bourgogne Franche-Comté, UMR 6213 CNRS-UBFC, UTINAM, Besançon, F-25000, France
| | - Stéphane Roux
- Université Bourgogne Franche-Comté, UMR 6213 CNRS-UBFC, UTINAM, Besançon, F-25000, France
| | - Nicolas Richet
- Université de Reims-Champagne-Ardennes, Plateau Technique Mobile de Cytométrie Environnementale MOBICYTE Mobicyte, Reims, F-51100, France
| | | | - Pascal Chastagner
- Université de Lorraine, CNRS, CRAN, Nancy, F-54000, France,CHRU de Nancy, Hôpital d’enfants - Brabois, Vandoeuvre-lès-Nancy, F-54500, France
| | - Sophie Pinel
- Université de Lorraine, CNRS, CRAN, Nancy, F-54000, France,Correspondence: Sophie Pinel, Email
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Yeon C, Im JM, Kim M, Kim YR, Chung E. Cranial and Spinal Window Preparation for in vivo Optical Neuroimaging in Rodents and Related Experimental Techniques. Exp Neurobiol 2022; 31:131-146. [PMID: 35786637 PMCID: PMC9272117 DOI: 10.5607/en22015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 06/03/2022] [Accepted: 06/15/2022] [Indexed: 11/19/2022] Open
Abstract
Optical neuroimaging provides an effective neuroscience tool for multi-scale investigation of the neural structures and functions, ranging from molecular, cellular activities to the inter-regional connectivity assessment. Amongst experimental preparations, the implementation of an artificial window to the central nervous system (CNS) is primarily required for optical visualization of the CNS and associated brain activities through the opaque skin and bone. Either thinning down or removing portions of the skull or spine is necessary for unobstructed long-term in vivo observations, for which types of the cranial and spinal window and applied materials vary depending on the study objectives. As diversely useful, a window can be designed to accommodate other experimental methods such as electrophysiology or optogenetics. Moreover, auxiliary apparatuses would allow the recording in synchrony with behavior of large-scale brain connectivity signals across the CNS, such as olfactory bulb, cerebral cortex, cerebellum, and spinal cord. Such advancements in the cranial and spinal window have resulted in a paradigm shift in neuroscience, enabling in vivo investigation of the brain function and dysfunction at the microscopic, cellular level. This Review addresses the types and classifications of windows used in optical neuroimaging while describing how to perform in vivo studies using rodent models in combination with other experimental modalities during behavioral tests. The cranial and spinal window has enabled longitudinal examination of evolving neural mechanisms via in situ visualization of the brain. We expect transformable and multi-functional cranial and spinal windows to become commonplace in neuroscience laboratories, further facilitating advances in optical neuroimaging systems.
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Affiliation(s)
- Chanmi Yeon
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Jeong Myo Im
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Minsung Kim
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Young Ro Kim
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA.,Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
| | - Euiheon Chung
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.,AI Graduate School, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.,Research Center for Photon Science Technology, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
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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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5
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Current Review of Optical Neural Interfaces for Clinical Applications. MICROMACHINES 2021; 12:mi12080925. [PMID: 34442547 PMCID: PMC8400671 DOI: 10.3390/mi12080925] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/20/2021] [Accepted: 07/29/2021] [Indexed: 11/16/2022]
Abstract
Neural interfaces, which enable the recording and stimulation of living neurons, have emerged as valuable tools in understanding the brain in health and disease, as well as serving as neural prostheses. While neural interfaces are typically based on electrical transduction, alternative energy modalities have been explored to create safe and effective approaches. Among these approaches, optical methods of linking neurons to the outside world have gained attention because light offers high spatial selectivity and decreased invasiveness. Here, we review the current state-of-art of optical neural interfaces and their clinical applications. Optical neural interfaces can be categorized into optical control and optical readout, each of which can be divided into intrinsic and extrinsic approaches. We discuss the advantages and disadvantages of each of these methods and offer a comparison of relative performance. Future directions, including their clinical opportunities, are discussed with regard to the optical properties of biological tissue.
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Wang HL, Chen JW, Yang SH, Lo YC, Pan HC, Liang YW, Wang CF, Yang Y, Kuo YT, Lin YC, Chou CY, Lin SH, Chen YY. Multimodal Optical Imaging to Investigate Spatiotemporal Changes in Cerebrovascular Function in AUDA Treatment of Acute Ischemic Stroke. Front Cell Neurosci 2021; 15:655305. [PMID: 34149359 PMCID: PMC8209306 DOI: 10.3389/fncel.2021.655305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 05/10/2021] [Indexed: 01/03/2023] Open
Abstract
Administration of 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) has been demonstrated to alleviate infarction following ischemic stroke. Reportedly, the main effect of AUDA is exerting anti-inflammation and neovascularization via the inhibition of soluble epoxide hydrolase. However, the major contribution of this anti-inflammation and neovascularization effect in the acute phase of stroke is not completely elucidated. To investigate the neuroprotective effects of AUDA in acute ischemic stroke, we combined laser speckle contrast imaging and optical intrinsic signal imaging techniques with the implantation of a lab-designed cranial window. Forepaw stimulation was applied to assess the functional changes via measuring cerebral metabolic rate of oxygen (CMRO2) that accompany neural activity. The rats that received AUDA in the acute phase of photothrombotic ischemia stroke showed a 30.5 ± 8.1% reduction in the ischemic core, 42.3 ± 15.1% reduction in the ischemic penumbra (p < 0.05), and 42.1 ± 4.6% increase of CMRO2 in response to forepaw stimulation at post-stroke day 1 (p < 0.05) compared with the control group (N = 10 for each group). Moreover, at post-stroke day 3, increased functional vascular density was observed in AUDA-treated rats (35.9 ± 1.9% higher than that in the control group, p < 0.05). At post-stroke day 7, a 105.4% ± 16.4% increase of astrocytes (p < 0.01), 30.0 ± 10.9% increase of neurons (p < 0.01), and 65.5 ± 15.0% decrease of microglia (p < 0.01) were observed in the penumbra region in AUDA-treated rats (N = 5 for each group). These results suggested that AUDA affects the anti-inflammation at the beginning of ischemic injury and restores neuronal metabolic rate of O2 and tissue viability. The neovascularization triggered by AUDA restored CBF and may contribute to ischemic infarction reduction at post-stroke day 3. Moreover, for long-term neuroprotection, astrocytes in the penumbra region may play an important role in protecting neurons from apoptotic injury.
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Affiliation(s)
- Han-Lin Wang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Jia-Wei Chen
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shih-Hung Yang
- Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Chun Lo
- The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Han-Chi Pan
- National Laboratory Animal Center, Taipei, Taiwan
| | - Yao-Wen Liang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ching-Fu Wang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi Yang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yun-Ting Kuo
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi-Chen Lin
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chin-Yu Chou
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Sheng-Huang Lin
- Department of Neurology, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.,Department of Neurology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - You-Yin Chen
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan.,The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
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Cramer SW, Carter RE, Aronson JD, Kodandaramaiah SB, Ebner TJ, Chen CC. Through the looking glass: A review of cranial window technology for optical access to the brain. J Neurosci Methods 2021; 354:109100. [PMID: 33600850 DOI: 10.1016/j.jneumeth.2021.109100] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 02/07/2021] [Accepted: 02/09/2021] [Indexed: 02/07/2023]
Abstract
Deciphering neurologic function is a daunting task, requiring understanding the neuronal networks and emergent properties that arise from the interactions among single neurons. Mechanistic insights into neuronal networks require tools that simultaneously assess both single neuron activity and the consequent mesoscale output. The development of cranial window technologies, in which the skull is thinned or replaced with a synthetic optical interface, has enabled monitoring neuronal activity from subcellular to mesoscale resolution in awake, behaving animals when coupled with advanced microscopy techniques. Here we review recent achievements in cranial window technologies, appraise the relative merits of each design and discuss the future research in cranial window design.
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Affiliation(s)
- Samuel W Cramer
- Department of Neurosurgery, University of Minnesota, 420 Delaware St SE, Mayo D429, MMC 96, Twin Cities, Minneapolis, MN, 55455, USA
| | - Russell E Carter
- Department of Neuroscience, University of Minnesota, Twin Cities, Room 421, 2001 Sixth Street S.E., Minneapolis, MN, 55455 MN, USA
| | - Justin D Aronson
- Department of Neuroscience, University of Minnesota, Twin Cities, Room 421, 2001 Sixth Street S.E., Minneapolis, MN, 55455 MN, USA
| | - Suhasa B Kodandaramaiah
- Department of Mechanical Engineering, University of Minnesota, Twin Cities, MN, USA; Department of Biomedical Engineering, University of Minnesota, Twin Cities, MN, USA; Graduate Program in Neuroscience, University of Minnesota, Twin Cities, MN, USA
| | - Timothy J Ebner
- Department of Neuroscience, University of Minnesota, Twin Cities, Room 421, 2001 Sixth Street S.E., Minneapolis, MN, 55455 MN, USA.
| | - Clark C Chen
- Department of Neurosurgery, University of Minnesota, 420 Delaware St SE, Mayo D429, MMC 96, Twin Cities, Minneapolis, MN, 55455, USA.
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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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Tehrani KF, Koukourakis N, Czarske J, Mortensen LJ. In situ measurement of the isoplanatic patch for imaging through intact bone. JOURNAL OF BIOPHOTONICS 2021; 14:e202000160. [PMID: 32844561 PMCID: PMC10599401 DOI: 10.1002/jbio.202000160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
Wavefront-shaping (WS) enables imaging through scattering tissues like bone, which is important for neuroscience and bone-regeneration research. WS corrects for the optical aberrations at a given depth and field-of-view (FOV) within the sample; the extent of the validity of which is limited to a region known as the isoplanatic patch (IP). Knowing this parameter helps to estimate the number of corrections needed for WS imaging over a given FOV. In this paper, we first present direct transmissive measurement of murine skull IP using digital optical phase conjugation based focusing. Second, we extend our previously reported phase accumulation ray tracing (PART) method to provide in-situ in-silico estimation of IP, called correlative PART (cPART). Our results show an IP range of 1 to 3 μm for mice within an age range of 8 to 14 days old and 1.00 ± 0.25 μm in a 12-week old adult skull. Consistency between the two measurement approaches indicates that cPART can be used to approximate the IP before a WS experiment, which can be used to calculate the number of corrections required within a given field of view.
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Affiliation(s)
- Kayvan Forouhesh Tehrani
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA, 30602, USA
| | - Nektarios Koukourakis
- TU Dresden, Chair of Measurement and Sensor System Technique, Helmholtzstr. 18, 01062 Dresden, Germany
- Competence Center for Biomedical Computational Laser Systems (BIOLAS), TU Dresden, Germany
| | - Jürgen Czarske
- TU Dresden, Chair of Measurement and Sensor System Technique, Helmholtzstr. 18, 01062 Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, Germany
- Competence Center for Biomedical Computational Laser Systems (BIOLAS), TU Dresden, Germany
| | - Luke J Mortensen
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA, 30602, USA
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA 30602, USA
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10
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Intact in vivo visualization of telencephalic microvasculature in medaka using optical coherence tomography. Sci Rep 2020; 10:19831. [PMID: 33199719 PMCID: PMC7669881 DOI: 10.1038/s41598-020-76468-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 10/28/2020] [Indexed: 11/09/2022] Open
Abstract
To date, various human disease models in small fish-such as medaka (Oryzias lapties)-have been developed for medical and pharmacological studies. Although genetic and environmental homogeneities exist, disease progressions can show large individual differences in animal models. In this study, we established an intact in vivo angiographic approach and explored vascular networks in the telencephalon of wild-type adult medaka using the spectral-domain optical coherence tomography. Our approach, which required neither surgical operations nor labeling agents, allowed to visualize blood vessels in medaka telencephala as small as about 8 µm, that is, almost the size of the blood cells of medaka. Besides, we could show the three-dimensional microvascular distribution in the medaka telencephalon. Therefore, the intact in vivo imaging via optical coherence tomography can be used to perform follow-up studies on cerebrovascular alterations in metabolic syndrome and their associations with neurodegenerative disease models in medaka.
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11
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Rakymzhan A, Li Y, Tang P, Wang RK. Optical microangiography reveals temporal and depth-resolved hemodynamic change in mouse barrel cortex during whisker stimulation. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200117RR. [PMID: 32945154 PMCID: PMC7495356 DOI: 10.1117/1.jbo.25.9.096005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/04/2020] [Indexed: 06/01/2023]
Abstract
SIGNIFICANCE Cerebral blood flow (CBF) regulation at neurovascular coupling (NVC) plays an important role in normal brain functioning to support oxygen delivery to activating neurons. Therefore, studying the mechanisms of CBF adjustment is crucial for the improved understanding of brain activity. AIM We investigated the temporal profile of hemodynamic signal change in mouse cortex caused by neural activation and its variation over cortical depth. APPROACH Following the cranial window surgery, intrinsic optical signal imaging (IOSI) was used to spatially locate the activated region in mouse cortex during whisker stimulation. Optical microangiography (OMAG), the functional extension of optical coherence tomography, was applied to image the activated and control regions identified by IOSI. Temporal profiles of hemodynamic response signals obtained by IOSI and OMAG were compared, and OMAG signal was analyzed over cortical layers. RESULTS Our results showed that the hemodynamic response to neural activity revealed by blood flow change signal signal through IOSI is slower than that observed by OMAG signal. OMAG also indicated the laminar variation of the response over cortical depth, showing the largest response in cortical layer IV. CONCLUSIONS Overall, we demonstrated the development and application of dual-modality imaging system composed of IOSI and OMAG, which may have potential to enable the future investigations of depth-resolved CBF and to provide the insights of hemodynamic events associated with the NVC.
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Affiliation(s)
- Adiya Rakymzhan
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Yuandong Li
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Peijun Tang
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
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12
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Le N, Subhash HM, Kilpatrick-Liverman L, Wang RK. Noninvasive multimodal imaging by integrating optical coherence tomography with autofluorescence imaging for dental applications. JOURNAL OF BIOPHOTONICS 2020; 13:e202000026. [PMID: 32191393 DOI: 10.1002/jbio.202000026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/09/2020] [Accepted: 03/16/2020] [Indexed: 05/25/2023]
Abstract
We report the development of an integrated multifunctional imaging system capable of providing anatomical (optical coherence tomography, OCT), functional (OCT angiography, OCTA) and molecular imaging (light-induced autofluorescence, LIAF) for in vivo dental applications. Blue excitation light (405 nm) was used for LIAF imaging, while the OCT was powered by a 1310 nm swept laser source. A red-green-blue digital camera, with a 450 nm cut-on broadband optical filter, was used for LIAF detection. The exciting light source and camera were integrated directly with the OCT scanning probe. The integrated system used two noninvasive imaging modalities to improve the speed of in vivo OCT data collection and to better target the regions of interest. The newly designed system maintained the ability to detect differences between healthy and hypomineralized teeth, identify dental biofilm and visualize the microvasculature of gingival tissue. The development of the integrated OCT-LIAF system provides an opportunity to conduct clinical studies more efficiently, examining changes in oral conditions over time.
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Affiliation(s)
- Nhan Le
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Hrebesh M Subhash
- Clinical Method Development - Oral Care, Colgate-Palmolive Company, Piscataway, NJ, USA
| | | | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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13
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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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14
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Choi WJ, Paulson B, Yu S, Wang RK, Kim JK. Mean-Subtraction Method for De-shadowing of Tail Artifacts in Cerebral OCTA Images: A Proof of Concept. MATERIALS 2020; 13:ma13092024. [PMID: 32357466 PMCID: PMC7254351 DOI: 10.3390/ma13092024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 01/25/2023]
Abstract
When imaging brain vasculature with optical coherence tomography angiography (OCTA), volumetric analysis of cortical vascular networks in OCTA datasets is frequently challenging due to the presence of artifacts, which appear as multiple-scattering tails beneath superficial large vessels in OCTA images. These tails shadow underlying small vessels, making the assessment of vascular morphology in the deep cortex difficult. In this work, we introduce an image processing technique based on mean subtraction of the depth profile that can effectively reduce these tails to better reveal small hidden vessels compared to the current tail removal approach. With the improved vascular image quality, we demonstrate that this simple method can provide better visualization of three-dimensional vascular network topology for quantitative cerebrovascular studies.
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Affiliation(s)
- Woo June Choi
- School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 06974, Korea; (W.J.C.); (S.Y.)
| | - Bjorn Paulson
- Biomedical Engineering Research Center, Asan Institute for Life Science, Asan Medical Center, Seoul 05505, Korea;
| | - Sungwook Yu
- School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 06974, Korea; (W.J.C.); (S.Y.)
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA;
| | - Jun Ki Kim
- Biomedical Engineering Research Center, Asan Institute for Life Science, Asan Medical Center, Seoul 05505, Korea;
- Department of Convergence Medicine, University of Ulsan College of Medicine, Seoul 05505, Korea
- Correspondence: ; Tel.: +82-2-3010-8619
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15
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Tang P, Li Y, Rakymzhan A, Xie Z, Wang RK. Measurement and visualization of stimulus-evoked tissue dynamics in mouse barrel cortex using phase-sensitive optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2020; 11:699-710. [PMID: 32206393 PMCID: PMC7041479 DOI: 10.1364/boe.381332] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/04/2019] [Accepted: 01/02/2020] [Indexed: 05/24/2023]
Abstract
We describe a method to measure tissue dynamics in mouse barrel cortex during functional activation via phase-sensitive optical coherence tomography (PhS-OCT). The method measures the phase changes in OCT signals, which are induced by the tissue volume change, upon which to localize the activated tissue region. Phase unwrapping, compensation and normalization are applied to increase the dynamic range of the OCT phase detection. To guide the OCT scanning, intrinsic optical signal imaging (IOSI) system equipped with a green light laser source (532 nm) is integrated with the PhS-OCT system to provide a full field time-lapsed images of the reflectance that is used to identify the transversal 2D localized tissue response in the mouse brain. The OCT results show a localized decrease in the OCT phase signal in the activated region of the mouse brain tissue. The decrease in the phase signal may be originated from the brain tissue compression caused by the vasodilatation in the activated region. The activated region revealed in the cross-sectional OCT image is consistent with that identified by the IOSI imaging, indicating the phase change in the OCT signals may associate with the changes in the corresponding hemodynamics. In vivo localized tissue dynamics in the barrel cortex at depth during whisker stimulation is observed and monitored in this study.
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16
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Meiburger KM, Chen Z, Sinz C, Hoover E, Minneman M, Ensher J, Kittler H, Leitgeb RA, Drexler W, Liu M. Automatic skin lesion area determination of basal cell carcinoma using optical coherence tomography angiography and a skeletonization approach: Preliminary results. JOURNAL OF BIOPHOTONICS 2019; 12:e201900131. [PMID: 31100191 PMCID: PMC7065618 DOI: 10.1002/jbio.201900131] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/15/2019] [Accepted: 05/16/2019] [Indexed: 05/05/2023]
Abstract
Cutaneous blood flow plays a key role in numerous physiological and pathological processes and has significant potential to be used as a biomarker to diagnose skin diseases such as basal cell carcinoma (BCC). The determination of the lesion area and vascular parameters within it, such as vessel density, is essential for diagnosis, surgical treatment and follow-up procedures. Here, an automatic skin lesion area determination algorithm based on optical coherence tomography angiography (OCTA) images is presented for the first time. The blood vessels are segmented within the OCTA images and then skeletonized. Subsequently, the skeleton is searched over the volume and numerous quantitative vascular parameters are calculated. The vascular density is then used to segment the lesion area. The algorithm is tested on both nodular and superficial BCC, and comparing with dermatological and histological results, the proposed method provides an accurate, non-invasive, quantitative and automatic tool for BCC lesion area determination.
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Affiliation(s)
- Kristen M. Meiburger
- Biolab, Department of Electronics and TelecommunicationsPolitecnico di TorinoTorinoItaly
| | - Zhe Chen
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Christoph Sinz
- Department of DermatologyMedical University of ViennaViennaAustria
| | | | | | | | - Harald Kittler
- Department of DermatologyMedical University of ViennaViennaAustria
| | - Rainer A. Leitgeb
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Wolfgang Drexler
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Mengyang Liu
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
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17
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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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18
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Zhang P, Li L, Lin L, Shi J, Wang LV. In vivo superresolution photoacoustic computed tomography by localization of single dyed droplets. LIGHT, SCIENCE & APPLICATIONS 2019; 8:36. [PMID: 30962922 PMCID: PMC6445830 DOI: 10.1038/s41377-019-0147-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 03/21/2019] [Accepted: 03/22/2019] [Indexed: 05/03/2023]
Abstract
Photoacoustic (PA) computed tomography (PACT) is a noninvasive hybrid imaging technique that combines optical excitation and acoustic detection to realize high contrast, high resolution, and deep penetration in biological tissues. However, the spatial resolution of PACT is limited by acoustic diffraction. Here, we report in vivo superresolution PACT, which breaks the acoustic diffraction limit by localizing the centers of single dyed droplets that are flowing in blood vessels. The droplets were prepared by dissolving hydrophobic absorbing dye in oil, followed by mixing with water. The dyed droplets generate much higher-amplitude PA signals than blood and can flow smoothly in vessels; thus, they are excellent tracers for localization-based superresolution imaging. The in vivo resolution enhancement was demonstrated by continuously imaging the cortical layer of a mouse brain during droplet injection. The droplets that were flowing in the vessels were localized, and their center positions were used to construct a superresolution image that exhibits sharper features and more finely resolved vascular details. An improvement in spatial resolution by a factor of 6 has been realized in vivo by the droplet localization technique.
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Affiliation(s)
- Pengfei Zhang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130 USA
- Present Address: School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, 300072 China
| | - Lei Li
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, 1200 E. California Blvd., MC 138-78, Pasadena, CA 91125 USA
| | - Li Lin
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, 1200 E. California Blvd., MC 138-78, Pasadena, CA 91125 USA
| | - Junhui Shi
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, 1200 E. California Blvd., MC 138-78, Pasadena, CA 91125 USA
| | - Lihong V. Wang
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, 1200 E. California Blvd., MC 138-78, Pasadena, CA 91125 USA
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19
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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: 55] [Impact Index Per Article: 9.2] [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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20
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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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21
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Xu J, Song S, Li Y, Wang RK. Complex-based OCT angiography algorithm recovers microvascular information better than amplitude- or phase-based algorithms in phase-stable systems. Phys Med Biol 2017; 63:015023. [PMID: 29049034 DOI: 10.1088/1361-6560/aa94bc] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Optical coherence tomography angiography (OCTA) is increasingly becoming a popular inspection tool for biomedical imaging applications. By exploring the amplitude, phase and complex information available in OCT signals, numerous algorithms have been proposed that contrast functional vessel networks within microcirculatory tissue beds. However, it is not clear which algorithm delivers optimal imaging performance. Here, we investigate systematically how amplitude and phase information have an impact on the OCTA imaging performance, to establish the relationship of amplitude and phase stability with OCT signal-to-noise ratio (SNR), time interval and particle dynamics. With either repeated A-scan or repeated B-scan imaging protocols, the amplitude noise increases with the increase of OCT SNR; however, the phase noise does the opposite, i.e. it increases with the decrease of OCT SNR. Coupled with experimental measurements, we utilize a simple Monte Carlo (MC) model to simulate the performance of amplitude-, phase- and complex-based algorithms for OCTA imaging, the results of which suggest that complex-based algorithms deliver the best performance when the phase noise is < ~40 mrad. We also conduct a series of in vivo vascular imaging in animal models and human retina to verify the findings from the MC model through assessing the OCTA performance metrics of vessel connectivity, image SNR and contrast-to-noise ratio. We show that for all the metrics assessed, the complex-based algorithm delivers better performance than either the amplitude- or phase-based algorithms for both the repeated A-scan and the B-scan imaging protocols, which agrees well with the conclusion drawn from the MC simulations.
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Affiliation(s)
- Jingjiang Xu
- Department of Bioengineering, University of Washington, Seattle, WA 98195, United States of America
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22
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Baran U, Choi WJ, Li Y, Wang RK. Tail artifact removal in OCT angiography images of rodent cortex. JOURNAL OF BIOPHOTONICS 2017; 10:1421-1429. [PMID: 27600882 PMCID: PMC5340634 DOI: 10.1002/jbio.201600194] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/16/2016] [Accepted: 08/21/2016] [Indexed: 05/11/2023]
Abstract
Optical coherence tomography angiography (OCTA) is a surging non-invasive, label-free, in vivo volumetric imaging method, currently being translated to clinical ophthalmology and becoming popular in neuroscience. Despite its attractiveness, there is an inherent issue of using OCT angiograms for quantitative cerebrovascular studies: The dynamic scattering of moving erythrocytes within pial vasculature creates tail-like artifacts that shadow the capillary vessels in the deeper layers of cortex. This false flow effect is relatively benign for qualitative visualization purposes, but it might have a significant impact on quantitative interpretation of angiographic results. In this work, we propose a simple image processing method to remove these tail artifacts in depth-resolved OCTA images using an adaptive enface mask generated with OCT structural images. We demonstrate the effectiveness of our method by comparing vessel densities and vessel similarities of depth-resolved OCT angiograms in a stroke study in a rodent model, in vivo. Thanks to the ability of seeing through the tails of pial vessels, capillary vessels beneath these vessels could be recovered to some extend in the deeper layers of mouse cerebral cortex, leading to a more accurate quantification. Tail artifact removed enface OCT angiogram of deeper layer in vivo mouse cortex.
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Affiliation(s)
- Utku Baran
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Electrical Engineering, University of Washington, Seattle, WA, USA
| | - Woo June Choi
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Yuandong Li
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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23
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Mokbul MI. Optical Coherence Tomography: Basic Concepts and Applications in Neuroscience Research. J Med Eng 2017; 2017:3409327. [PMID: 29214158 PMCID: PMC5682075 DOI: 10.1155/2017/3409327] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/22/2017] [Accepted: 09/14/2017] [Indexed: 12/28/2022] Open
Abstract
Optical coherence tomography is a micrometer-scale imaging modality that permits label-free, cross-sectional imaging of biological tissue microstructure using tissue backscattering properties. After its invention in the 1990s, OCT is now being widely used in several branches of neuroscience as well as other fields of biomedical science. This review study reports an overview of OCT's applications in several branches or subbranches of neuroscience such as neuroimaging, neurology, neurosurgery, neuropathology, and neuroembryology. This study has briefly summarized the recent applications of OCT in neuroscience research, including a comparison, and provides a discussion of the remaining challenges and opportunities in addition to future directions. The chief aim of the review study is to draw the attention of a broad neuroscience community in order to maximize the applications of OCT in other branches of neuroscience too, and the study may also serve as a benchmark for future OCT-based neuroscience research. Despite some limitations, OCT proves to be a useful imaging tool in both basic and clinical neuroscience research.
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Affiliation(s)
- Mobin Ibne Mokbul
- Notre Dame College, Motijheel Circular Road, Arambagh, Motijheel, Dhaka 1000, Bangladesh
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24
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Wang RK, Zhang Q, Li Y, Song S. Optical coherence tomography angiography-based capillary velocimetry. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:66008. [PMID: 28617921 PMCID: PMC5472241 DOI: 10.1117/1.jbo.22.6.066008] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 05/19/2017] [Indexed: 05/05/2023]
Abstract
Challenge persists in the field of optical coherence tomography (OCT) when it is required to quantify capillary blood flow within tissue beds in vivo. We propose a useful approach to statistically estimate the mean capillary flow velocity using a model-based statistical method of eigendecomposition (ED) analysis of the complex OCT signals obtained with the OCT angiography (OCTA) scanning protocol. ED-based analysis is achieved by the covariance matrix of the ensemble complex OCT signals, upon which the eigenvalues and eigenvectors that represent the subsets of the signal makeup are calculated. From this analysis, the signals due to moving particles can be isolated by employing an adaptive regression filter to remove the eigencomponents that represent static tissue signals. The mean frequency (MF) of moving particles can be estimated by the first lag-one autocorrelation of the corresponding eigenvectors. Three important parameters are introduced, including the blood flow signal power representing the presence of blood flow (i.e., OCTA signals), the MF indicating the mean velocity of blood flow, and the frequency bandwidth describing the temporal flow heterogeneity within a scanned tissue volume. The proposed approach is tested using scattering phantoms, in which microfluidic channels are used to simulate the functional capillary vessels that are perfused with the scattering intralipid solution. The results indicate a linear relationship between the MF and mean flow velocity. In vivo animal experiments are also conducted by imaging mouse brain with distal middle cerebral artery ligation to test the capability of the method to image the changes in capillary flows in response to an ischemic insult, demonstrating the practical usefulness of the proposed method for providing important quantifiable information about capillary tissue beds in the investigations of neurological conditions in vivo.
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Affiliation(s)
- 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:
| | - Qinqin Zhang
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Yuandong Li
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Shaozhen Song
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
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25
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Coles JA, Myburgh E, Brewer JM, McMenamin PG. Where are we? The anatomy of the murine cortical meninges revisited for intravital imaging, immunology, and clearance of waste from the brain. Prog Neurobiol 2017; 156:107-148. [PMID: 28552391 DOI: 10.1016/j.pneurobio.2017.05.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 04/25/2017] [Accepted: 05/08/2017] [Indexed: 12/15/2022]
Abstract
Rapid progress is being made in understanding the roles of the cerebral meninges in the maintenance of normal brain function, in immune surveillance, and as a site of disease. Most basic research on the meninges and the neural brain is now done on mice, major attractions being the availability of reporter mice with fluorescent cells, and of a huge range of antibodies useful for immunocytochemistry and the characterization of isolated cells. In addition, two-photon microscopy through the unperforated calvaria allows intravital imaging of the undisturbed meninges with sub-micron resolution. The anatomy of the dorsal meninges of the mouse (and, indeed, of all mammals) differs considerably from that shown in many published diagrams: over cortical convexities, the outer layer, the dura, is usually thicker than the inner layer, the leptomeninx, and both layers are richly vascularized and innervated, and communicate with the lymphatic system. A membrane barrier separates them and, in disease, inflammation can be localized to one layer or the other, so experimentalists must be able to identify the compartment they are studying. Here, we present current knowledge of the functional anatomy of the meninges, particularly as it appears in intravital imaging, and review their role as a gateway between the brain, blood, and lymphatics, drawing on information that is scattered among works on different pathologies.
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Affiliation(s)
- Jonathan A Coles
- Centre for Immunobiology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, Sir Graeme Davis Building, University of Glasgow, Glasgow, G12 8TA, United Kingdom.
| | - Elmarie Myburgh
- Centre for Immunology and Infection Department of Biology, University of York, Wentworth Way, Heslington, York YO10 5DD, United Kingdom
| | - James M Brewer
- Centre for Immunobiology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, Sir Graeme Davis Building, University of Glasgow, Glasgow, G12 8TA, United Kingdom
| | - Paul G McMenamin
- Department of Anatomy & Developmental Biology, School of Biomedical and Psychological Sciences and Monash Biomedical Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, 10 Chancellor's Walk, Clayton, Victoria, 3800, Australia
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Cain MD, Salimi H, Gong Y, Yang L, Hamilton SL, Heffernan JR, Hou J, Miller MJ, Klein RS. Virus entry and replication in the brain precedes blood-brain barrier disruption during intranasal alphavirus infection. J Neuroimmunol 2017; 308:118-130. [PMID: 28501330 DOI: 10.1016/j.jneuroim.2017.04.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 04/27/2017] [Accepted: 04/27/2017] [Indexed: 12/25/2022]
Abstract
Viral infections of the central nervous system (CNS) are often associated with blood-brain barrier (BBB) disruption, yet the impact of virus replication and immune cell recruitment on BBB integrity are incompletely understood. Using two-photon microscopy, we demonstrate that Venezuelan equine encephalitis virus (VEEV) strain TC83-GFP, a GFP expressing, attenuated strain with a G3A mutation within the 5' UTR that is associated with increased sensitivity to type I interferons (IFNs), does not directly impact BBB permeability. Following intranasal infection of both wild-type and IFN-induced protein with tetratricopeptide repeats 1 (IFIT1)-deficient mice, which fail to block TC83-specific RNA translation, virus spreads to the olfactory bulb and cortex via migration along axonal tracts of neurons originating from the olfactory neuroepithelium. Global dissemination of virus in the CNS by 2days post-infection (dpi) was associated with increased BBB permeability in the olfactory bulb, but not in the cortex or hindbrain, where permeability only increased after the recruitment of CX3CR1+ and CCR2+ mononuclear cells on 6 dpi, which corresponded with tight junction loss and claudin 5 redistribution. Importantly, despite higher levels of viral replication, similar results were obtained in IFIT1-deficient mice. These findings indicate that TC83 gains CNS access via anterograde axonal migration without directly altering BBB function and that mononuclear and endothelial cell interactions may underlie BBB disruption during alphavirus encephalitis.
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Affiliation(s)
- Matthew D Cain
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Hamid Salimi
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Yongfeng Gong
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Lihua Yang
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Samantha L Hamilton
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, United States
| | - James R Heffernan
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Jianghui Hou
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Mark J Miller
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, United States.
| | - Robyn S Klein
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, United States; Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, United States; Department of Neuroscience, Washington University School of Medicine, St Louis, MO 63110, United States.
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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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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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Baran U, Zhu W, Choi WJ, Omori M, Zhang W, Alkayed NJ, Wang RK. Automated segmentation and enhancement of optical coherence tomography-acquired images of rodent brain. J Neurosci Methods 2016; 270:132-137. [PMID: 27328369 DOI: 10.1016/j.jneumeth.2016.06.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 05/09/2016] [Accepted: 06/15/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND Optical coherence tomography (OCT) is a non-invasive optical imaging method that has proven useful in various fields such as ophthalmology, dermatology and neuroscience. In ophthalmology, significant progress has been made in retinal layer segmentation and enhancement of OCT images. There are also segmentation algorithms to separate epidermal and dermal layers in OCT-acquired images of human skin. NEW METHOD We describe simple image processing methods that allow automatic segmentation and enhancement of OCT images of rodent brain. RESULTS We demonstrate the effectiveness of the proposed methods for OCT-based microangiography (OMAG) and tissue injury mapping (TIM) of mouse cerebral cortex. The results show significant improvement in image contrast, delineation of tissue injury, allowing visualization of different layers of capillary beds. COMPARISON WITH EXISTING METHODS Previously reported methods for other applications are yet to be used in neuroscience due to the complexity of tissue anatomy, unique physiology and technical challenges. CONCLUSIONS OCT is a promising tool that provides high resolution in vivo microvascular and structural images of rodent brain. By automatically segmenting and enhancing OCT images, structural and microvascular changes in mouse cerebral cortex after stroke can be monitored in vivo with high contrast.
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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
| | - Wenbin Zhu
- Dept. of Anesthesiology and Perioperative Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Woo June Choi
- Dept. of Bioengineering, University of Washington, 3720 15th Ave. NE, Seattle, WA 98195, USA
| | - Michael Omori
- Dept. of Electrical Engineering, University of Washington, 185 Stevens Way, Seattle, WA 98195, USA
| | - Wenri Zhang
- Dept. of Anesthesiology and Perioperative Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Nabil J Alkayed
- Dept. of Anesthesiology and Perioperative Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Ruikang K Wang
- Dept. of Bioengineering, University of Washington, 3720 15th Ave. NE, Seattle, WA 98195, USA.
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Xu J, Wei W, Song S, Qi X, Wang RK. Scalable wide-field optical coherence tomography-based angiography for in vivo imaging applications. BIOMEDICAL OPTICS EXPRESS 2016; 7:1905-19. [PMID: 27231630 PMCID: PMC4871090 DOI: 10.1364/boe.7.001905] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/08/2016] [Accepted: 04/08/2016] [Indexed: 05/03/2023]
Abstract
Recent advances in optical coherence tomography (OCT)-based angiography have demonstrated a variety of biomedical applications in the diagnosis and therapeutic monitoring of diseases with vascular involvement. While promising, its imaging field of view (FOV) is however still limited (typically less than 9 mm(2)), which somehow slows down its clinical acceptance. In this paper, we report a high-speed spectral-domain OCT operating at 1310 nm to enable wide FOV up to 750 mm(2). Using optical microangiography (OMAG) algorithm, we are able to map vascular networks within living biological tissues. Thanks to 2,048 pixel-array line scan InGaAs camera operating at 147 kHz scan rate, the system delivers a ranging depth of ~7.5 mm and provides wide-field OCT-based angiography at a single data acquisition. We implement two imaging modes (i.e., wide-field mode and high-resolution mode) in the OCT system, which gives highly scalable FOV with flexible lateral resolution. We demonstrate scalable wide-field vascular imaging for multiple finger nail beds in human and whole brain in mice with skull left intact at a single 3D scan, promising new opportunities for wide-field OCT-based angiography for many clinical applications.
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Baran U, Choi WJ, Wang RK. Potential use of OCT-based microangiography in clinical dermatology. Skin Res Technol 2016; 22:238-246. [PMID: 26335451 PMCID: PMC4777681 DOI: 10.1111/srt.12255] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2015] [Indexed: 11/26/2022]
Abstract
BACKGROUND Optical coherence tomography (OCT) is a revolutionary imaging technique used commonly in ophthalmology, and on the way to become clinically viable alternative in dermatology due to its capability of acquiring histopathology level details of in vivo tissue, non-invasively. In this study, we demonstrate the capabilities of OCT-based microangiography in detecting high resolution, three-dimensional structural, and microvascular features of in vivo human skin with various conditions. METHODS A swept-source OCT system that operates on a central wavelength of 1310 nm with an A-line rate of 100 kHz is used in this study. We apply optical microangiography (OMAG) technique to visualize the structural and microvascular changes in tissue. RESULTS OMAG images provide detailed visualization of functional microvasculature of healthy human skin from cheek and forehead areas, abnormal skin conditions from face, chest and belly. Moreover, OMAG is capable of monitoring the progress of wound healing on human skin from arm, delivering unprecedented detail of microstructural and microvascular information during longitudinal wound healing process. CONCLUSION The presented results promise the clinical use of OCT angiography, aiming to treat prevalent cutaneous diseases, by detecting blood perfusion, and structural changes within human skin, in vivo.
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Affiliation(s)
- Utku Baran
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Electrical Engineering, University of Washington, Seattle, WA, USA
| | - Woo June Choi
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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OCT-based label-free in vivo lymphangiography within human skin and areola. Sci Rep 2016; 6:21122. [PMID: 26892830 PMCID: PMC4759696 DOI: 10.1038/srep21122] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/18/2016] [Indexed: 01/29/2023] Open
Abstract
Due to the limitations of current imaging techniques, visualization of lymphatic capillaries within tissue in vivo has been challenging. Here, we present a label-free high resolution optical coherence tomography (OCT) based lymphangiography (OLAG) within human skin in vivo. OLAG enables rapid (~seconds) mapping of lymphatic networks, along with blood vessel networks, over 8 mm x 8 mm of human skin and 5 mm x 5 mm of human areola. Moreover, lymphatic system’s response to inflammation within human skin is monitored throughout an acne lesion development over 7 days. The demonstrated results promise OLAG as a revolutionary tool in the clinical research and treatment of patients with pathologic conditions such as cancer, diabetes, and autoimmune diseases.
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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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Zhang A, Zhang Q, Wang RK. Minimizing projection artifacts for accurate presentation of choroidal neovascularization in OCT micro-angiography. BIOMEDICAL OPTICS EXPRESS 2015; 6:4130-43. [PMID: 26504660 PMCID: PMC4605069 DOI: 10.1364/boe.6.004130] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 09/16/2015] [Accepted: 09/17/2015] [Indexed: 05/02/2023]
Abstract
Current optical coherence tomography (OCT) based micro-angiography is prone to a projection (or tailing) effect due to the high scattering property of blood within overlying patent vessels, creating artifacts that interfere with the interpretation of retinal angiographic results. In this work, the projection effect in OCT micro-angiography is examined and its causality is explained by strong light scattering and photon propagation within blood. A simple practical approach is then introduced to minimize these artifacts presented in the outer retinal avascular space, especially useful for examining clinical cases with choroidal neovascularization (CNV). Demonstrated through in-vivo human posterior eye imaging of healthy and CNV subjects, the proposed method is shown effective to eliminate the projection artifacts in outer retinal space of OCT micro-angiography, resulting in better visualization of the pathological neovascularization when compared with the current common approaches. In addition, it is also shown that the proposed method is applicable to minimize the projection artifacts appearing in deep retinal layers.
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35
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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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Kazmi SMS, Richards LM, Schrandt CJ, Davis MA, Dunn AK. Expanding applications, accuracy, and interpretation of laser speckle contrast imaging of cerebral blood flow. J Cereb Blood Flow Metab 2015; 35:1076-84. [PMID: 25944593 PMCID: PMC4640282 DOI: 10.1038/jcbfm.2015.84] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/17/2015] [Accepted: 03/09/2015] [Indexed: 12/21/2022]
Abstract
Laser speckle contrast imaging (LSCI) provides a rapid characterization of cortical flow dynamics for functional monitoring of the microcirculation. The technique stems from interactions of laser light with moving particles. These interactions encode the encountered Doppler phenomena within a random interference pattern imaged in widefield, known as laser speckle. Studies of neurovascular function and coupling with LSCI have benefited from the real-time characterization of functional dynamics in the laboratory setting through quantification of perfusion dynamics. While the technique has largely been relegated to acute small animal imaging, its scalability is being assessed and characterized for both chronic and clinical neurovascular imaging.
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Affiliation(s)
- S M Shams Kazmi
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Lisa M Richards
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Christian J Schrandt
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Mitchell A Davis
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Andrew K Dunn
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
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Lin JB, Phillips EH, Riggins TE, Sangha GS, Chakraborty S, Lee JY, Lycke RJ, Hernandez CL, Soepriatna AH, Thorne BRH, Yrineo AA, Goergen CJ. Imaging of small animal peripheral artery disease models: recent advancements and translational potential. Int J Mol Sci 2015; 16:11131-77. [PMID: 25993289 PMCID: PMC4463694 DOI: 10.3390/ijms160511131] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Accepted: 03/10/2015] [Indexed: 12/11/2022] Open
Abstract
Peripheral artery disease (PAD) is a broad disorder encompassing multiple forms of arterial disease outside of the heart. As such, PAD development is a multifactorial process with a variety of manifestations. For example, aneurysms are pathological expansions of an artery that can lead to rupture, while ischemic atherosclerosis reduces blood flow, increasing the risk of claudication, poor wound healing, limb amputation, and stroke. Current PAD treatment is often ineffective or associated with serious risks, largely because these disorders are commonly undiagnosed or misdiagnosed. Active areas of research are focused on detecting and characterizing deleterious arterial changes at early stages using non-invasive imaging strategies, such as ultrasound, as well as emerging technologies like photoacoustic imaging. Earlier disease detection and characterization could improve interventional strategies, leading to better prognosis in PAD patients. While rodents are being used to investigate PAD pathophysiology, imaging of these animal models has been underutilized. This review focuses on structural and molecular information and disease progression revealed by recent imaging efforts of aortic, cerebral, and peripheral vascular disease models in mice, rats, and rabbits. Effective translation to humans involves better understanding of underlying PAD pathophysiology to develop novel therapeutics and apply non-invasive imaging techniques in the clinic.
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Affiliation(s)
- Jenny B Lin
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Evan H Phillips
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Ti'Air E Riggins
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Gurneet S Sangha
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Sreyashi Chakraborty
- School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.
| | - Janice Y Lee
- Psychological Sciences, Purdue University, West Lafayette, IN 47907, USA.
| | - Roy J Lycke
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Clarissa L Hernandez
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Arvin H Soepriatna
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Bradford R H Thorne
- School of Sciences, Neuroscience, Purdue University, West Lafayette, IN 47907, USA.
| | - Alexa A Yrineo
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Craig J Goergen
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
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Zhang A, Wang RK. Feature space optical coherence tomography based micro-angiography. BIOMEDICAL OPTICS EXPRESS 2015; 6:1919-28. [PMID: 26137391 PMCID: PMC4467717 DOI: 10.1364/boe.6.001919] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/21/2015] [Accepted: 04/23/2015] [Indexed: 05/04/2023]
Abstract
Current optical coherence tomography (OCT) based micro-angiography is prone to noise that arises from static background. This work presents a novel feature space based optical micro-angiography (OMAG) method (fsOMAG) that can effectively differentiate flow signal from static background in the feature space. fsOMAG consists of two steps. In the first step a classification map is generated that provides criterion for classification in the second step to extract functional blood flow from experimental data set. The performance of fsOMAG is examined through phantom experiments and in-vivo human retinal imaging, and compared with the existing OMAG. The results indicate its potential for clinical applications.
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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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Baran U, Li Y, Choi WJ, Kalkan G, Wang RK. High resolution imaging of acne lesion development and scarring in human facial skin using OCT-based microangiography. Lasers Surg Med 2015; 47:231-8. [PMID: 25740313 DOI: 10.1002/lsm.22339] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2014] [Indexed: 11/10/2022]
Abstract
BACKGROUND AND OBJECTIVE Acne is a common skin disease that often leads to scarring. Collagen and other tissue damage from the inflammation of acne give rise to permanent skin texture and microvascular changes. In this study, we demonstrate the capabilities of optical coherence tomography-based microangiography in detecting high-resolution, three-dimensional structural, and microvascular features of in vivo human facial skin during acne lesion initiation and scar development. MATERIALS AND METHODS A real time swept source optical coherence tomography system is used in this study to acquire volumetric images of human skin. The system operates on a central wavelength of 1,310 nm with an A-line rate of 100 kHz, and with an extended imaging range (∼12 mm in air). The system uses a handheld imaging probe to image acne lesion on a facial skin of a volunteer. We utilize optical microangiography (OMAG) technique to evaluate the changes in microvasculature and tissue structure. RESULTS Thanks to the high sensitivity of OMAG, we are able to image microvasculature up to capillary level and visualize the remodeled vessels around the acne lesion. Moreover, vascular density change derived from OMAG measurement is provided as an alternative biomarker for the assessment of human skin diseases. In contrast to other techniques like histology or microscopy, our technique made it possible to image 3D tissue structure and microvasculature up to 1.5 mm depth in vivo without the need of exogenous contrast agents. CONCLUSIONS The presented results are promising to facilitate clinical trials aiming to treat acne lesion scarring, as well as other prevalent skin diseases, by detecting cutaneous blood flow and structural changes within human skin in vivo.
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Affiliation(s)
- Utku Baran
- Department of Bioengineering, University of Washington, Seattle, Washington; Department of Electrical Engineering, University of Washington, Seattle, Washington
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Baran U, Li Y, Choi WJ, Kalkan G, Wang RK. High resolution imaging of acne lesion development and scarring in human facial skin using OCT-based microangiography. Lasers Surg Med 2015. [PMID: 25740313 DOI: 10.1002/lsm.v47.3] [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] [Indexed: 05/03/2023]
Abstract
BACKGROUND AND OBJECTIVE Acne is a common skin disease that often leads to scarring. Collagen and other tissue damage from the inflammation of acne give rise to permanent skin texture and microvascular changes. In this study, we demonstrate the capabilities of optical coherence tomography-based microangiography in detecting high-resolution, three-dimensional structural, and microvascular features of in vivo human facial skin during acne lesion initiation and scar development. MATERIALS AND METHODS A real time swept source optical coherence tomography system is used in this study to acquire volumetric images of human skin. The system operates on a central wavelength of 1,310 nm with an A-line rate of 100 kHz, and with an extended imaging range (∼12 mm in air). The system uses a handheld imaging probe to image acne lesion on a facial skin of a volunteer. We utilize optical microangiography (OMAG) technique to evaluate the changes in microvasculature and tissue structure. RESULTS Thanks to the high sensitivity of OMAG, we are able to image microvasculature up to capillary level and visualize the remodeled vessels around the acne lesion. Moreover, vascular density change derived from OMAG measurement is provided as an alternative biomarker for the assessment of human skin diseases. In contrast to other techniques like histology or microscopy, our technique made it possible to image 3D tissue structure and microvasculature up to 1.5 mm depth in vivo without the need of exogenous contrast agents. CONCLUSIONS The presented results are promising to facilitate clinical trials aiming to treat acne lesion scarring, as well as other prevalent skin diseases, by detecting cutaneous blood flow and structural changes within human skin in vivo.
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Affiliation(s)
- Utku Baran
- Department of Bioengineering, University of Washington, Seattle, Washington; Department of Electrical Engineering, University of Washington, Seattle, Washington
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