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Chen H, Mirg S, Gaddale P, Agrawal S, Li M, Nguyen V, Xu T, Li Q, Liu J, Tu W, Liu X, Drew PJ, Zhang N, Gluckman BJ, Kothapalli S. Multiparametric Brain Hemodynamics Imaging Using a Combined Ultrafast Ultrasound and Photoacoustic System. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2401467. [PMID: 38884161 PMCID: PMC11336909 DOI: 10.1002/advs.202401467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/25/2024] [Indexed: 06/18/2024]
Abstract
Studying brain-wide hemodynamic responses to different stimuli at high spatiotemporal resolutions can help gain new insights into the mechanisms of neuro- diseases and -disorders. Nonetheless, this task is challenging, primarily due to the complexity of neurovascular coupling, which encompasses interdependent hemodynamic parameters including cerebral blood volume (CBV), cerebral blood flow (CBF), and cerebral oxygen saturation (SO2). The current brain imaging technologies exhibit inherent limitations in resolution, sensitivity, and imaging depth, restricting their capacity to comprehensively capture the intricacies of cerebral functions. To address this, a multimodal functional ultrasound and photoacoustic (fUSPA) imaging platform is reported, which integrates ultrafast ultrasound and multispectral photoacoustic imaging methods in a compact head-mountable device, to quantitatively map individual dynamics of CBV, CBF, and SO2 as well as contrast agent enhanced brain imaging at high spatiotemporal resolutions. Following systematic characterization, the fUSPA system is applied to study brain-wide cerebrovascular reactivity (CVR) at single-vessel resolution via relative changes in CBV, CBF, and SO2 in response to hypercapnia stimulation. These results show that cortical veins and arteries exhibit differences in CVR in the stimulated state and consistent anti-correlation in CBV oscillations during the resting state, demonstrating the multiparametric fUSPA system's unique capabilities in investigating complex mechanisms of brain functions.
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Affiliation(s)
- Haoyang Chen
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Center for Neural EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Shubham Mirg
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Center for Neural EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Prameth Gaddale
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Sumit Agrawal
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Menghan Li
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Van Nguyen
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Tianbao Xu
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Qiong Li
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Jinyun Liu
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Wenyu Tu
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Xiao Liu
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Institute for Computational and Data SciencesThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Patrick J. Drew
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Center for Neural EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of Engineering Science and MechanicsThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of BiologyThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of NeurosurgeryThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Nanyin Zhang
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Center for Neural EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Bruce J. Gluckman
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Center for Neural EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of Engineering Science and MechanicsThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Department of NeurosurgeryThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Sri‐Rajasekhar Kothapalli
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Center for Neural EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Penn State Cancer InstituteThe Pennsylvania State UniversityHersheyPA17033USA
- Graduate Program in AcousticsThe Pennsylvania State UniversityUniversity ParkPA16802USA
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2
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Nolte DD. Coherent light scattering from cellular dynamics in living tissues. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:036601. [PMID: 38433567 DOI: 10.1088/1361-6633/ad2229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/24/2024] [Indexed: 03/05/2024]
Abstract
This review examines the biological physics of intracellular transport probed by the coherent optics of dynamic light scattering from optically thick living tissues. Cells and their constituents are in constant motion, composed of a broad range of speeds spanning many orders of magnitude that reflect the wide array of functions and mechanisms that maintain cellular health. From the organelle scale of tens of nanometers and upward in size, the motion inside living tissue is actively driven rather than thermal, propelled by the hydrolysis of bioenergetic molecules and the forces of molecular motors. Active transport can mimic the random walks of thermal Brownian motion, but mean-squared displacements are far from thermal equilibrium and can display anomalous diffusion through Lévy or fractional Brownian walks. Despite the average isotropic three-dimensional environment of cells and tissues, active cellular or intracellular transport of single light-scattering objects is often pseudo-one-dimensional, for instance as organelle displacement persists along cytoskeletal tracks or as membranes displace along the normal to cell surfaces, albeit isotropically oriented in three dimensions. Coherent light scattering is a natural tool to characterize such tissue dynamics because persistent directed transport induces Doppler shifts in the scattered light. The many frequency-shifted partial waves from the complex and dynamic media interfere to produce dynamic speckle that reveals tissue-scale processes through speckle contrast imaging and fluctuation spectroscopy. Low-coherence interferometry, dynamic optical coherence tomography, diffusing-wave spectroscopy, diffuse-correlation spectroscopy, differential dynamic microscopy and digital holography offer coherent detection methods that shed light on intracellular processes. In health-care applications, altered states of cellular health and disease display altered cellular motions that imprint on the statistical fluctuations of the scattered light. For instance, the efficacy of medical therapeutics can be monitored by measuring the changes they induce in the Doppler spectra of livingex vivocancer biopsies.
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Affiliation(s)
- David D Nolte
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907, United States of America
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3
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Chen H, Mirg S, Gaddale P, Agrawal S, Li M, Nguyen V, Xu T, Li Q, Liu J, Tu W, Liu X, Drew PJ, Zhang N, Gluckman BJ, Kothapalli SR. Dissecting Multiparametric Cerebral Hemodynamics using Integrated Ultrafast Ultrasound and Multispectral Photoacoustic Imaging. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566048. [PMID: 37986863 PMCID: PMC10659547 DOI: 10.1101/2023.11.07.566048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Understanding brain-wide hemodynamic responses to different stimuli at high spatiotemporal resolutions can help study neuro-disorders and brain functions. However, the existing brain imaging technologies have limited resolution, sensitivity, imaging depth and provide information about only one or two hemodynamic parameters. To address this, we propose a multimodal functional ultrasound and photoacoustic (fUSPA) imaging platform, which integrates ultrafast ultrasound and multispectral photoacoustic imaging methods in a compact head-mountable device, to quantitatively map cerebral blood volume (CBV), cerebral blood flow (CBF), oxygen saturation (SO2) dynamics as well as contrast agent enhanced brain imaging with high spatiotemporal resolutions. After systematic characterization, the fUSPA system was applied to quantitatively study the changes in brain hemodynamics and vascular reactivity at single vessel resolution in response to hypercapnia stimulation. Our results show an overall increase in brain-wide CBV, CBF, and SO2, but regional differences in singular cortical veins and arteries and a reproducible anti-correlation pattern between venous and cortical hemodynamics, demonstrating the capabilities of the fUSPA system for providing multiparametric cerebrovascular information at high-resolution and sensitivity, that can bring insights into the complex mechanisms of neurodiseases.
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Affiliation(s)
- Haoyang Chen
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Shubham Mirg
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Prameth Gaddale
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sumit Agrawal
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Menghan Li
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Van Nguyen
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Tianbao Xu
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Qiong Li
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Jinyun Liu
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Wenyu Tu
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Xiao Liu
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Institute for Computational and Data Sciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Patrick J. Drew
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA 16802, USA
| | - Nanyin Zhang
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Bruce J. Gluckman
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sri-Rajasekhar Kothapalli
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Penn State Cancer Institute, The Pennsylvania State University, Hershey, PA 17033, USA
- Graduate Program in Acoustics, The Pennsylvania State University, University Park, PA 16802, USA
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4
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DPSF: a Novel Dual-Parametric Sigmoid Function for Optical Coherence Tomography Image Enhancement. Med Biol Eng Comput 2022; 60:1111-1121. [PMID: 35233689 DOI: 10.1007/s11517-022-02538-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 02/13/2022] [Indexed: 10/19/2022]
Abstract
Speckle noise reduces the image contrast significantly making the highly scattering structures boundaries difficult to distinguish. This has limited the usage of optical coherence tomography (OCT) images in clinical routine and hindered its potential by depriving clinicians from assessing useful information that are needed in disease monitoring, treatment, progression, and decision making. To overcome this limitation, we propose a fast and robust OCT image enhancement framework using non-linear statistical parametric technique. In the proposed framework, we utilize prior statistical information to model the image to follow Gaussian distribution. After which, a newly designed dual-parametric sigmoid function (DPSF) is utilized to control the dynamic range and contrast level of the image. To balance the intensity range and contrast level, both linear and non-linear normalization operations are performed, then followed by a mapping operation to obtain the enhanced image. Experimentation results on the three OCT vendors show that the proposed method obtained high values in EME, PSNR, SSIM, ρ, and low value in MSE of 36.72, 38.87, 0.87, 0.98, and 25.12 for Cirrus; 40.77, 41.84, 0.89, 0.98, and 22.15 for Spectralis; and 30.81, 32.10, 0.81, 0.96, and 28.55 for Topcon OCT devices, respectively. The proposed DPSF framework performs better than the state-of-the-art methods and improves the interpretability and perception of the OCT images, which can provide clinicians and computer vision program with good quantitative and qualitative information.
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5
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Şencan İ, Esipova T, Kılıç K, Li B, Desjardins M, Yaseen MA, Wang H, Porter JE, Kura S, Fu B, Secomb TW, Boas DA, Vinogradov SA, Devor A, Sakadžić S. Optical measurement of microvascular oxygenation and blood flow responses in awake mouse cortex during functional activation. J Cereb Blood Flow Metab 2022; 42:510-525. [PMID: 32515672 PMCID: PMC8985437 DOI: 10.1177/0271678x20928011] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The cerebral cortex has a number of conserved morphological and functional characteristics across brain regions and species. Among them, the laminar differences in microvascular density and mitochondrial cytochrome c oxidase staining suggest potential laminar variability in the baseline O2 metabolism and/or laminar variability in both O2 demand and hemodynamic response. Here, we investigate the laminar profile of stimulus-induced intravascular partial pressure of O2 (pO2) transients to stimulus-induced neuronal activation in fully awake mice using two-photon phosphorescence lifetime microscopy. Our results demonstrate that stimulus-induced changes in intravascular pO2 are conserved across cortical layers I-IV, suggesting a tightly controlled neurovascular response to provide adequate O2 supply across cortical depth. In addition, we observed a larger change in venular O2 saturation (ΔsO2) compared to arterioles, a gradual increase in venular ΔsO2 response towards the cortical surface, and absence of the intravascular "initial dip" previously reported under anesthesia. This study paves the way for quantification of layer-specific cerebral O2 metabolic responses, facilitating investigation of brain energetics in health and disease and informed interpretation of laminar blood oxygen level dependent functional magnetic resonance imaging signals.
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Affiliation(s)
- İkbal Şencan
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Tatiana Esipova
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Kıvılcım Kılıç
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Baoqiang Li
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Michèle Desjardins
- Department of Physics, Engineering Physics and Optics, Université Laval, QC, Canada
| | - Mohammad A Yaseen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Hui Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Jason E Porter
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Sreekanth Kura
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Buyin Fu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, AZ, USA
| | - David A Boas
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Sergei A Vinogradov
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Anna Devor
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.,Department of Biomedical Engineering, Boston University, Boston, MA, USA.,Department of Neurosciences, University of California San Diego, La Jolla, CA, USA.,Department of Radiology, University of California San Diego, La Jolla, CA, USA
| | - Sava Sakadžić
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
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6
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Abdelfattah AS, Ahuja S, Akkin T, Allu SR, Brake J, Boas DA, Buckley EM, Campbell RE, Chen AI, Cheng X, Čižmár T, Costantini I, De Vittorio M, Devor A, Doran PR, El Khatib M, Emiliani V, Fomin-Thunemann N, Fainman Y, Fernandez-Alfonso T, Ferri CGL, Gilad A, Han X, Harris A, Hillman EMC, Hochgeschwender U, Holt MG, Ji N, Kılıç K, Lake EMR, Li L, Li T, Mächler P, Miller EW, Mesquita RC, Nadella KMNS, Nägerl UV, Nasu Y, Nimmerjahn A, Ondráčková P, Pavone FS, Perez Campos C, Peterka DS, Pisano F, Pisanello F, Puppo F, Sabatini BL, Sadegh S, Sakadzic S, Shoham S, Shroff SN, Silver RA, Sims RR, Smith SL, Srinivasan VJ, Thunemann M, Tian L, Tian L, Troxler T, Valera A, Vaziri A, Vinogradov SA, Vitale F, Wang LV, Uhlířová H, Xu C, Yang C, Yang MH, Yellen G, Yizhar O, Zhao Y. Neurophotonic tools for microscopic measurements and manipulation: status report. NEUROPHOTONICS 2022; 9:013001. [PMID: 35493335 PMCID: PMC9047450 DOI: 10.1117/1.nph.9.s1.013001] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Neurophotonics was launched in 2014 coinciding with the launch of the BRAIN Initiative focused on development of technologies for advancement of neuroscience. For the last seven years, Neurophotonics' agenda has been well aligned with this focus on neurotechnologies featuring new optical methods and tools applicable to brain studies. While the BRAIN Initiative 2.0 is pivoting towards applications of these novel tools in the quest to understand the brain, this status report reviews an extensive and diverse toolkit of novel methods to explore brain function that have emerged from the BRAIN Initiative and related large-scale efforts for measurement and manipulation of brain structure and function. Here, we focus on neurophotonic tools mostly applicable to animal studies. A companion report, scheduled to appear later this year, will cover diffuse optical imaging methods applicable to noninvasive human studies. For each domain, we outline the current state-of-the-art of the respective technologies, identify the areas where innovation is needed, and provide an outlook for the future directions.
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Affiliation(s)
- Ahmed S. Abdelfattah
- Brown University, Department of Neuroscience, Providence, Rhode Island, United States
| | - Sapna Ahuja
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Taner Akkin
- University of Minnesota, Department of Biomedical Engineering, Minneapolis, Minnesota, United States
| | - Srinivasa Rao Allu
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Joshua Brake
- Harvey Mudd College, Department of Engineering, Claremont, California, United States
| | - David A. Boas
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Erin M. Buckley
- Georgia Institute of Technology and Emory University, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
- Emory University, Department of Pediatrics, Atlanta, Georgia, United States
| | - Robert E. Campbell
- University of Tokyo, Department of Chemistry, Tokyo, Japan
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
| | - Anderson I. Chen
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Xiaojun Cheng
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Tomáš Čižmár
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Irene Costantini
- University of Florence, European Laboratory for Non-Linear Spectroscopy, Department of Biology, Florence, Italy
- National Institute of Optics, National Research Council, Rome, Italy
| | - Massimo De Vittorio
- Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies, Arnesano, Italy
| | - Anna Devor
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Patrick R. Doran
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Mirna El Khatib
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | | | - Natalie Fomin-Thunemann
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Yeshaiahu Fainman
- University of California San Diego, Department of Electrical and Computer Engineering, La Jolla, California, United States
| | - Tomas Fernandez-Alfonso
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Christopher G. L. Ferri
- University of California San Diego, Departments of Neurosciences, La Jolla, California, United States
| | - Ariel Gilad
- The Hebrew University of Jerusalem, Institute for Medical Research Israel–Canada, Department of Medical Neurobiology, Faculty of Medicine, Jerusalem, Israel
| | - Xue Han
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Andrew Harris
- Weizmann Institute of Science, Department of Brain Sciences, Rehovot, Israel
| | | | - Ute Hochgeschwender
- Central Michigan University, Department of Neuroscience, Mount Pleasant, Michigan, United States
| | - Matthew G. Holt
- University of Porto, Instituto de Investigação e Inovação em Saúde (i3S), Porto, Portugal
| | - Na Ji
- University of California Berkeley, Department of Physics, Berkeley, California, United States
| | - Kıvılcım Kılıç
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Evelyn M. R. Lake
- Yale School of Medicine, Department of Radiology and Biomedical Imaging, New Haven, Connecticut, United States
| | - Lei Li
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
| | - Tianqi Li
- University of Minnesota, Department of Biomedical Engineering, Minneapolis, Minnesota, United States
| | - Philipp Mächler
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Evan W. Miller
- University of California Berkeley, Departments of Chemistry and Molecular & Cell Biology and Helen Wills Neuroscience Institute, Berkeley, California, United States
| | | | | | - U. Valentin Nägerl
- Interdisciplinary Institute for Neuroscience University of Bordeaux & CNRS, Bordeaux, France
| | - Yusuke Nasu
- University of Tokyo, Department of Chemistry, Tokyo, Japan
| | - Axel Nimmerjahn
- Salk Institute for Biological Studies, Waitt Advanced Biophotonics Center, La Jolla, California, United States
| | - Petra Ondráčková
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Francesco S. Pavone
- National Institute of Optics, National Research Council, Rome, Italy
- University of Florence, European Laboratory for Non-Linear Spectroscopy, Department of Physics, Florence, Italy
| | - Citlali Perez Campos
- Columbia University, Zuckerman Mind Brain Behavior Institute, New York, United States
| | - Darcy S. Peterka
- Columbia University, Zuckerman Mind Brain Behavior Institute, New York, United States
| | - Filippo Pisano
- Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies, Arnesano, Italy
| | - Ferruccio Pisanello
- Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies, Arnesano, Italy
| | - Francesca Puppo
- University of California San Diego, Departments of Neurosciences, La Jolla, California, United States
| | - Bernardo L. Sabatini
- Harvard Medical School, Howard Hughes Medical Institute, Department of Neurobiology, Boston, Massachusetts, United States
| | - Sanaz Sadegh
- University of California San Diego, Departments of Neurosciences, La Jolla, California, United States
| | - Sava Sakadzic
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Shy Shoham
- New York University Grossman School of Medicine, Tech4Health and Neuroscience Institutes, New York, New York, United States
| | - Sanaya N. Shroff
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - R. Angus Silver
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Ruth R. Sims
- Sorbonne University, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Spencer L. Smith
- University of California Santa Barbara, Department of Electrical and Computer Engineering, Santa Barbara, California, United States
| | - Vivek J. Srinivasan
- New York University Langone Health, Departments of Ophthalmology and Radiology, New York, New York, United States
| | - Martin Thunemann
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Lei Tian
- Boston University, Departments of Electrical Engineering and Biomedical Engineering, Boston, Massachusetts, United States
| | - Lin Tian
- University of California Davis, Department of Biochemistry and Molecular Medicine, Davis, California, United States
| | - Thomas Troxler
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Antoine Valera
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Alipasha Vaziri
- Rockefeller University, Laboratory of Neurotechnology and Biophysics, New York, New York, United States
- The Rockefeller University, The Kavli Neural Systems Institute, New York, New York, United States
| | - Sergei A. Vinogradov
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Flavia Vitale
- Center for Neuroengineering and Therapeutics, Departments of Neurology, Bioengineering, Physical Medicine and Rehabilitation, Philadelphia, Pennsylvania, United States
| | - Lihong V. Wang
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
| | - Hana Uhlířová
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Chris Xu
- Cornell University, School of Applied and Engineering Physics, Ithaca, New York, United States
| | - Changhuei Yang
- California Institute of Technology, Departments of Electrical Engineering, Bioengineering and Medical Engineering, Pasadena, California, United States
| | - Mu-Han Yang
- University of California San Diego, Department of Electrical and Computer Engineering, La Jolla, California, United States
| | - Gary Yellen
- Harvard Medical School, Department of Neurobiology, Boston, Massachusetts, United States
| | - Ofer Yizhar
- Weizmann Institute of Science, Department of Brain Sciences, Rehovot, Israel
| | - Yongxin Zhao
- Carnegie Mellon University, Department of Biological Sciences, Pittsburgh, Pennsylvania, United States
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7
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Network-driven anomalous transport is a fundamental component of brain microvascular dysfunction. Nat Commun 2021; 12:7295. [PMID: 34911962 PMCID: PMC8674232 DOI: 10.1038/s41467-021-27534-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 11/18/2021] [Indexed: 12/17/2022] Open
Abstract
Blood microcirculation supplies neurons with oxygen and nutrients, and contributes to clearing their neurotoxic waste, through a dense capillary network connected to larger tree-like vessels. This complex microvascular architecture results in highly heterogeneous blood flow and travel time distributions, whose origin and consequences on brain pathophysiology are poorly understood. Here, we analyze highly-resolved intracortical blood flow and transport simulations to establish the physical laws governing the macroscopic transport properties in the brain micro-circulation. We show that network-driven anomalous transport leads to the emergence of critical regions, whether hypoxic or with high concentrations of amyloid-β, a waste product centrally involved in Alzheimer's Disease. We develop a Continuous-Time Random Walk theory capturing these dynamics and predicting that such critical regions appear much earlier than anticipated by current empirical models under mild hypoperfusion. These findings provide a framework for understanding and modelling the impact of microvascular dysfunction in brain diseases, including Alzheimer's Disease.
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8
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Merkle CW, Augustin M, Harper DJ, Gesperger J, Lichtenegger A, Eugui P, Garhöfer G, Glösmann M, Baumann B. High-resolution, depth-resolved vascular leakage measurements using contrast-enhanced, correlation-gated optical coherence tomography in mice. BIOMEDICAL OPTICS EXPRESS 2021; 12:1774-1791. [PMID: 33996197 PMCID: PMC8086440 DOI: 10.1364/boe.415227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 01/22/2021] [Accepted: 01/24/2021] [Indexed: 06/09/2023]
Abstract
Vascular leakage plays a key role in vision-threatening retinal diseases such as diabetic retinopathy and age-related macular degeneration. Fluorescence angiography is the current gold standard for identification of leaky vasculature in vivo, however it lacks depth resolution, providing only 2D images that complicate precise identification and localization of pathological vessels. Optical coherence tomography (OCT) has been widely adopted for clinical ophthalmology due to its high, micron-scale resolution and rapid volumetric scanning capabilities. Nevertheless, OCT cannot currently identify leaky blood vessels. To address this need, we have developed a new method called exogenous contrast-enhanced leakage OCT (ExCEL-OCT) which identifies the diffusion of tracer particles around leaky vasculature following injection of a contrast agent. We apply this method to a mouse model of retinal neovascularization and demonstrate high-resolution 3D vascular leakage measurements in vivo for the first time.
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Affiliation(s)
- Conrad W. Merkle
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Marco Augustin
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Danielle J. Harper
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Johanna Gesperger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Antonia Lichtenegger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Pablo Eugui
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Martin Glösmann
- Core Facility for Research and Technology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Bernhard Baumann
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
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9
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Zhu J, Bernucci MT, Merkle CW, Srinivasan VJ. Visibility of microvessels in Optical Coherence Tomography angiography depends on angular orientation. JOURNAL OF BIOPHOTONICS 2020; 13:e202000090. [PMID: 32468737 PMCID: PMC7737355 DOI: 10.1002/jbio.202000090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 05/02/2023]
Abstract
Optical Coherence Tomography angiography (OCTA) is a widespread tool for depth-resolved imaging of chorioretinal vasculature with single microvessel resolution. To improve the clinical interpretation of OCTA, the conditions affecting visualization of microvessels must be defined. Here we inject a scattering plasma tracer (Intralipid) during OCTA imaging of the anesthetized rat eye. In the retina, we find that interlaminar (vertical) vessels that connect laminae have one-fourth to one-third the OCTA red blood cell to tracer (RBC-to-tracer) signal ratio of intralaminar (horizontal) vessels. This finding suggests that the OCTA signal from microvessels depends on angular orientation, making vertically-oriented vessels more difficult to visualize using intrinsic contrast alone. Clinicians should be aware of this potential artifact when interpreting OCTA.
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Affiliation(s)
- Jun Zhu
- Biomedical Engineering Department, University of California Davis, Davis, California
| | - Marcel T. Bernucci
- Biomedical Engineering Department, University of California Davis, Davis, California
| | - Conrad W. Merkle
- Biomedical Engineering Department, University of California Davis, Davis, California
| | - Vivek J. Srinivasan
- Biomedical Engineering Department, University of California Davis, Davis, California
- Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, California
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10
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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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11
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Palma-Chavez JA, Kim W, Serafino M, Jo JA, Charoenphol P, Applegate BE. Methylene blue-filled biodegradable polymer particles as a contrast agent for optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2020; 11:4255-4274. [PMID: 32923040 PMCID: PMC7449750 DOI: 10.1364/boe.399322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/30/2020] [Accepted: 07/06/2020] [Indexed: 05/11/2023]
Abstract
Optical coherence tomography (OCT) images largely lack molecular information or molecular contrast. We address that issue here, reporting on the development of biodegradable micro and nano-spheres loaded with methylene blue (MB) as molecular contrast agents for OCT. MB is a constituent of FDA approved therapies and widely used as a dye in off-label clinical applications. The sequestration of MB within the polymer reduced toxicity and improved signal strength by drastically reducing the production of singlet oxygen and leuco-MB. The former leads to tissue damage and the latter to reduced image contrast. The spheres are also strongly scattering which improves molecular contrast signal localization and enhances signal strength. We demonstrate that these contrast agents may be imaged using both pump-probe OCT and photothermal OCT, using a 830 nm frequency domain OCT system and a 1.3 µm swept source OCT system. We also show that these contrast agents may be functionalized and targeted to specific receptors, e.g. the VCAM receptor known to be overexpressed in inflammation.
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Affiliation(s)
- Jorge A. Palma-Chavez
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Wihan Kim
- Department of Otolaryngology–Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
| | - Michael Serafino
- Department of Electrical and Computer Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Javier A. Jo
- Department of Electrical and Computer Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Phapanin Charoenphol
- Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Brian E. Applegate
- Department of Otolaryngology–Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
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12
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Merkle CW, Augustin M, Harper DJ, Baumann B. Indocyanine green provides absorption and spectral contrast for optical coherence tomography at 840 nm in vivo. OPTICS LETTERS 2020; 45:2359-2362. [PMID: 32287239 DOI: 10.1364/ol.380051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 01/10/2020] [Indexed: 05/25/2023]
Abstract
In recent years, there has been growing interest in the application of exogenous contrast agents to supplement the traditional strengths of optical coherence tomography (OCT) and provide additional biological information. In this Letter, we present how indocyanine green, a common fluorescent contrast agent approved by the United States Food and Drug Administration, can provide absorption and spectral contrast for OCT imaging in the mouse eye in vivo. We further demonstrate high stability of spectral contrast measurements for the long-term monitoring of contrast agents in spite of fluctuations in intensity.
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13
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Si P, Honkala A, de la Zerda A, Smith BR. Optical Microscopy and Coherence Tomography of Cancer in Living Subjects. Trends Cancer 2020; 6:205-222. [PMID: 32101724 DOI: 10.1016/j.trecan.2020.01.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 01/05/2020] [Accepted: 01/07/2020] [Indexed: 12/16/2022]
Abstract
Intravital microscopy (IVM) and optical coherency tomography (OCT) are two powerful optical imaging tools that allow visualization of dynamic biological activities in living subjects with subcellular resolutions. Recent advances in labeling and label-free techniques empower IVM and OCT for a wide range of preclinical and clinical cancer imaging, providing profound insights into the complex physiological, cellular, and molecular behaviors of tumors. Preclinical IVM and OCT have elucidated many otherwise inscrutable aspects of cancer biology, while clinical applications of IVM and OCT are revolutionizing cancer diagnosis and therapies. We review important progress in the fields of IVM and OCT for cancer imaging in living subjects, highlighting key technological developments and their emerging applications in fundamental cancer biology research and clinical oncology investigation.
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Affiliation(s)
- Peng Si
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA; Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 94305, USA
| | - Alexander Honkala
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Adam de la Zerda
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA; Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 94305, USA; Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA; The Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
| | - Bryan Ronain Smith
- Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 94305, USA; Department of Biomedical Engineering and Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA.
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14
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Merkle CW, Zhu J, Bernucci MT, Srinivasan VJ. Dynamic Contrast Optical Coherence Tomography reveals laminar microvascular hemodynamics in the mouse neocortex in vivo. Neuroimage 2019; 202:116067. [PMID: 31394180 DOI: 10.1016/j.neuroimage.2019.116067] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 07/01/2019] [Accepted: 08/01/2019] [Indexed: 12/18/2022] Open
Abstract
Studies of flow-metabolism coupling often presume that microvessel architecture is a surrogate for blood flow. To test this assumption, we introduce an in vivo Dynamic Contrast Optical Coherence Tomography (DyC-OCT) method to quantify layer-resolved microvascular blood flow and volume across the full depth of the mouse neocortex, where the angioarchitecture has been previously described. First, we cross-validate average DyC-OCT cortical flow against conventional Doppler OCT flow. Next, with laminar DyC-OCT, we discover that layer 4 consistently exhibits the highest microvascular blood flow, approximately two-fold higher than the outer cortical layers. While flow differences between layers are well-explained by microvascular volume and density, flow differences between subjects are better explained by transit time. Finally, from layer-resolved tracer enhancement, we also infer that microvascular hematocrit increases in deep cortical layers, consistent with predictions of plasma skimming. Altogether, our results show that while the cortical blood supply derives mainly from the pial surface, laminar hemodynamics ensure that the energetic needs of individual cortical layers are met. The laminar trends reported here provide data that links predictions based on the cortical angioarchitecture to cerebrovascular physiology in vivo.
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Affiliation(s)
- Conrad W Merkle
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, USA
| | - Jun Zhu
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, USA
| | - Marcel T Bernucci
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, USA
| | - Vivek J Srinivasan
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, USA; Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, CA, 95817, USA.
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15
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Li B, Esipova TV, Sencan I, Kılıç K, Fu B, Desjardins M, Moeini M, Kura S, Yaseen MA, Lesage F, Østergaard L, Devor A, Boas DA, Vinogradov SA, Sakadžić S. More homogeneous capillary flow and oxygenation in deeper cortical layers correlate with increased oxygen extraction. eLife 2019; 8:42299. [PMID: 31305237 PMCID: PMC6636997 DOI: 10.7554/elife.42299] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 07/01/2019] [Indexed: 01/01/2023] Open
Abstract
Our understanding of how capillary blood flow and oxygen distribute across cortical layers to meet the local metabolic demand is incomplete. We addressed this question by using two-photon imaging of resting-state microvascular oxygen partial pressure (PO2) and flow in the whisker barrel cortex in awake mice. Our measurements in layers I-V show that the capillary red-blood-cell flux and oxygenation heterogeneity, and the intracapillary resistance to oxygen delivery, all decrease with depth, reaching a minimum around layer IV, while the depth-dependent oxygen extraction fraction is increased in layer IV, where oxygen demand is presumably the highest. Our findings suggest that more homogeneous distribution of the physiological observables relevant to oxygen transport to tissue is an important part of the microvascular network adaptation to local brain metabolism. These results will inform the biophysical models of layer-specific cerebral oxygen delivery and consumption and improve our understanding of the diseases that affect cerebral microcirculation.
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Affiliation(s)
- Baoqiang Li
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Tatiana V Esipova
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, United States.,Department of Chemistry, University of Pennsylvania, Philadelphia, United States
| | - Ikbal Sencan
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Kıvılcım Kılıç
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Buyin Fu
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Michele Desjardins
- Department of Radiology, University of California, San Diego, La Jolla, United States
| | - Mohammad Moeini
- Institute of Biomedical Engineering, École Polytechnique de Montréal, Montréal, Canada.,Research Centre, Montreal Heart Institute, Montréal, Canada
| | - Sreekanth Kura
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Mohammad A Yaseen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Frederic Lesage
- Institute of Biomedical Engineering, École Polytechnique de Montréal, Montréal, Canada.,Research Centre, Montreal Heart Institute, Montréal, Canada
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Anna Devor
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States.,Department of Neurosciences, University of California, San Diego, La Jolla, United States.,Department of Radiology, University of California, San Diego, La Jolla, United States
| | - David A Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States.,Department of Biomedical Engineering, Boston University, Boston, United States
| | - Sergei A Vinogradov
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, United States.,Department of Chemistry, University of Pennsylvania, Philadelphia, United States
| | - Sava Sakadžić
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
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16
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Tang J, Erdener SE, Sunil S, Boas DA. Normalized field autocorrelation function-based optical coherence tomography three-dimensional angiography. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-8. [PMID: 30868803 PMCID: PMC6414735 DOI: 10.1117/1.jbo.24.3.036005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 02/06/2019] [Indexed: 05/02/2023]
Abstract
Optical coherence tomography angiography (OCTA) has been widely used for en face visualization of the microvasculature, but is challenged for real three-dimensional (3-D) topologic imaging due to the "tail" artifacts that appear below large vessels. Further, OCTA is generally incapable of differentiating descending arterioles from ascending venules. We introduce a normalized field autocorrelation function-based OCTA (g1-OCTA), which minimizes the tail artifacts and is capable of distinguishing penetrating arterioles from venules in the 3-D image. g1 ( τ ) is calculated from repeated optical coherence tomography (OCT) acquisitions for each spatial location. The decay amplitude of g1 ( τ ) is retrieved to represent the dynamics for each voxel. To account for the small g1 ( τ ) decay in capillaries where red blood cells are flowing slowly and discontinuously, Intralipid is injected to enhance the OCT signal. We demonstrate that the proposed technique realizes 3-D OCTA with negligible tail projections and the penetrating arteries are readily identified. In addition, compared to regular OCTA, the proposed g1-OCTA largely increased the depth-of-field. This technique provides a more accurate rendering of the vascular 3-D anatomy and has the potential for more quantitative characterization of vascular networks.
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Affiliation(s)
- Jianbo Tang
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, United States
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
- Address all correspondence to Jianbo Tang, E-mail:
| | - Sefik Evren Erdener
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, United States
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Smrithi Sunil
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - David A. Boas
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, United States
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
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17
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Yoshimura R, Choi DH, Fujimoto M, Uji A, Hiwatashi F, Ohbayashi K. Dynamic optical coherence tomography imaging of the lacrimal passage with an extrinsic contrast agent. BIOMEDICAL OPTICS EXPRESS 2019; 10:1482-1495. [PMID: 30891362 PMCID: PMC6420300 DOI: 10.1364/boe.10.001482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/31/2019] [Accepted: 01/31/2019] [Indexed: 06/09/2023]
Abstract
Recently, in vivo trans-conjunctiva optical coherence tomography (OCT) imaging of the lacrimal passage was demonstrated using a turbid commercial eye drop as an extrinsic contrast agent. However, static OCT images are not sufficient to unambiguously delineate the lumen boundary to render 3D lumen images of the lacrimal passage by segmentation. The turbid eye drop is expected to include small particles that flow and undergo Brownian motion and can be used as an extrinsic contrast agent for dynamic OCT. We conducted dynamic OCT measurements of the lacrimal passage using a swept source OCT system. Firstly, characterization of the dynamic OCT properties of the eye drop was performed. For improved delineation of the lumen boundary, we calculated the sum of the squared differences of intensities with two different normalization parameters. By making composite color images from OCT images and these two dynamic OCT images, we could execute unambiguous segmentation of the lumen of the lacrimal passage. Three-dimensional volumetric images of parts of the lacrimal passage, i.e., lacrimal canaliculus and lacrimal punctum, are demonstrated.
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Affiliation(s)
- Reiko Yoshimura
- Center for Natural Science, Kitasato University, 1-15-1 Kitazato, Minami, Sagamihara, Kanagawa 252-0374, Japan
| | - Dong-Hak Choi
- Center for Natural Science, Kitasato University, 1-15-1 Kitazato, Minami, Sagamihara, Kanagawa 252-0374, Japan
| | - Masahiro Fujimoto
- Department of Ophthalmology and Visual Sciences, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Akihito Uji
- Department of Ophthalmology and Visual Sciences, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Fumiko Hiwatashi
- Systems Engineering Inc., 2-19-24 Honkomagome, Bunkyo-ku, Tokyo 113-0021, Japan
| | - Kohji Ohbayashi
- Systems Engineering Inc., 2-19-24 Honkomagome, Bunkyo-ku, Tokyo 113-0021, Japan
- Advanced Imaging Co. Ltd., 2-23-9 Someino, Sakura, Chiba 285-0831, Japan
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18
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Bernucci MT, Merkle CW, Srinivasan VJ. Investigation of artifacts in retinal and choroidal OCT angiography with a contrast agent. BIOMEDICAL OPTICS EXPRESS 2018; 9:1020-1040. [PMID: 29541501 PMCID: PMC5846511 DOI: 10.1364/boe.9.001020] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 01/22/2018] [Accepted: 01/24/2018] [Indexed: 05/18/2023]
Abstract
Optical coherence tomography angiography (OCTA) has recently emerged for imaging vasculature in clinical ophthalmology. Yet, OCTA images contain artifacts that remain challenging to interpret. To help explain these artifacts, we perform contrast-enhanced OCTA with a custom-designed wide-field ophthalmoscope in rats in vivo. We choose an intravascular contrast agent (Intralipid) with particles that are more isotropically scattering and more symmetrically shaped than red blood cells (RBCs). Then, by examining how OCTA artifacts change after contrast agent injection, we attribute OCTA artifacts to RBC-specific properties. In this work, we investigate retinal and choroidal OCTA in rats with or without melanosomes, both before and after contrast agent injection, at a wavelength at which scattering dominates the image contrast (1300 nm). First, baseline images suggest that high backscattering of choroidal melanosomes accounts for the relatively dark appearance of choroidal vessel lumens in OCTA. Second, Intralipid injection tends to eliminate the hourglass pattern artifact in OCTA images of vessel lumens and highlights vertical capillaries that were previously faint in OCTA, showing that RBC orientation is important in determining OCTA signal. Third, Intralipid injection increases lumen signal without significantly affecting the tails, suggesting that projection artifacts, or tails, are due to RBC multiple scattering. Fourth, Intralipid injection increases the side-to-top signal ratio less in choroidal vessel lumens of pigmented rats, suggesting that melanosome multiple scattering makes the hourglass artifact less prominent. This study provides the first direct experimental in vivo evidence to explain light scattering-related artifacts in OCTA.
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Affiliation(s)
- Marcel T. Bernucci
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA
| | - Conrad W. Merkle
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA
| | - Vivek J. Srinivasan
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA
- Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, California, USA
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19
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Merkle CW, Chong SP, Kho AM, Zhu J, Dubra A, Srinivasan VJ. Visible light optical coherence microscopy of the brain with isotropic femtoliter resolution in vivo. OPTICS LETTERS 2018; 43:198-201. [PMID: 29328237 PMCID: PMC5953552 DOI: 10.1364/ol.43.000198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 11/21/2017] [Indexed: 05/10/2023]
Abstract
Most flying-spot optical coherence tomography and optical coherence microscopy (OCM) systems use a symmetric confocal geometry, where the detection path retraces the illumination path starting from and ending with the spatial mode of a single-mode optical fiber. Here we describe a visible light OCM instrument that breaks this symmetry to improve transverse resolution without sacrificing collection efficiency in scattering tissue. This was achieved by overfilling a water immersion objective on the illumination path while maintaining a conventional Gaussian mode detection path (1/e2 intensity diameter ∼0.82 Airy disks), enabling ∼1.1 μm full width at half-maximum (FWHM) transverse resolution. At the same time, a ∼0.9 μm FWHM axial resolution in tissue, achieved by a broadband visible light source, enabled femtoliter volume resolution. We characterized this instrument according to paraxial coherent microscopy theory and, finally, used it to image the meningeal layers, intravascular red blood cell-free layer, and myelinated axons in the mouse neocortex in vivo through the thinned skull.
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Affiliation(s)
- Conrad William Merkle
- Biomedical Engineering Department, University of California Davis, Davis, California 95616, USA
| | - Shau Poh Chong
- Biomedical Engineering Department, University of California Davis, Davis, California 95616, USA
| | - Aaron Michael Kho
- Biomedical Engineering Department, University of California Davis, Davis, California 95616, USA
| | - Jun Zhu
- Biomedical Engineering Department, University of California Davis, Davis, California 95616, USA
| | - Alfredo Dubra
- Byers Eye Institute, Stanford University, Palo Alto, California 94303, USA
| | - Vivek Jay Srinivasan
- Biomedical Engineering Department, University of California Davis, Davis, California 95616, USA
- Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, California 95817, USA
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20
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Harris SS, Boorman LW, Kennerley AJ, Sharp PS, Martin C, Redgrave P, Schwartz TH, Berwick J. Seizure epicenter depth and translaminar field potential synchrony underlie complex variations in tissue oxygenation during ictal initiation. Neuroimage 2017; 171:165-175. [PMID: 29294386 PMCID: PMC5883323 DOI: 10.1016/j.neuroimage.2017.12.088] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 12/01/2017] [Accepted: 12/27/2017] [Indexed: 12/21/2022] Open
Abstract
Whether functional hyperemia during epileptic activity is adequate to meet the heightened metabolic demand of such events is controversial. Whereas some studies have demonstrated hyperoxia during ictal onsets, other work has reported transient hypoxic episodes that are spatially dependent on local surface microvasculature. Crucially, how laminar differences in ictal evolution can affect subsequent cerebrovascular responses has not been thus far investigated, and is likely significant in view of possible laminar-dependent neurovascular mechanisms and angioarchitecture. We addressed this open question using a novel multi-modal methodology enabling concurrent measurement of cortical tissue oxygenation, blood flow and hemoglobin concentration, alongside laminar recordings of neural activity, in a urethane anesthetized rat model of recurrent seizures induced by 4-aminopyridine. We reveal there to be a close relationship between seizure epicenter depth, translaminar local field potential (LFP) synchrony and tissue oxygenation during the early stages of recurrent seizures, whereby deep layer seizures are associated with decreased cross laminar synchrony and prolonged periods of hypoxia, and middle layer seizures are accompanied by increased cross-laminar synchrony and hyperoxia. Through comparison with functional activation by somatosensory stimulation and graded hypercapnia, we show that these seizure-related cerebrovascular responses occur in the presence of conserved neural-hemodynamic and blood flow-volume coupling. Our data provide new insights into the laminar dependency of seizure-related neurovascular responses, which may reconcile inconsistent observations of seizure-related hypoxia in the literature, and highlight a potential layer-dependent vulnerability that may contribute to the harmful effects of clinical recurrent seizures. The relevance of our findings to perfusion-related functional neuroimaging techniques in epilepsy are also discussed.
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Affiliation(s)
- Samuel S Harris
- Department of Psychology, Neurovascular and Neuroimaging Research Group, University of Sheffield, Sheffield S10 2TN, UK.
| | - Luke W Boorman
- Department of Psychology, Neurovascular and Neuroimaging Research Group, University of Sheffield, Sheffield S10 2TN, UK
| | - Aneurin J Kennerley
- Department of Psychology, Neurovascular and Neuroimaging Research Group, University of Sheffield, Sheffield S10 2TN, UK
| | - Paul S Sharp
- Department of Psychology, Neurovascular and Neuroimaging Research Group, University of Sheffield, Sheffield S10 2TN, UK
| | - Chris Martin
- Department of Psychology, Neurovascular and Neuroimaging Research Group, University of Sheffield, Sheffield S10 2TN, UK
| | - Peter Redgrave
- Department of Psychology, Neurovascular and Neuroimaging Research Group, University of Sheffield, Sheffield S10 2TN, UK
| | - Theodore H Schwartz
- Department of Neurological Surgery, Brain and Mind Research Institute, Brain and Spine Center, Weill Cornell Medical College, New York Presbyterian Hospital, 525 East 68th Street, Box 99, New York, NY 10021, USA
| | - Jason Berwick
- Department of Psychology, Neurovascular and Neuroimaging Research Group, University of Sheffield, Sheffield S10 2TN, UK
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21
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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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22
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Petridou N, Siero JCW. Laminar fMRI: What can the time domain tell us? Neuroimage 2017; 197:761-771. [PMID: 28736308 DOI: 10.1016/j.neuroimage.2017.07.040] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 07/06/2017] [Accepted: 07/19/2017] [Indexed: 01/30/2023] Open
Abstract
The rapid developments in functional MRI (fMRI) acquisition methods and hardware technologies in recent years, particularly at high field (≥7 T), have enabled unparalleled visualization of functional detail at a laminar or columnar level, bringing fMRI close to the intrinsic resolution of brain function. These advances highlight the potential of high resolution fMRI to be a valuable tool to study the fundamental processing performed in cortical micro-circuits, and their interactions such as feedforward and feedback processes. Notably, because fMRI measures neuronal activity via hemodynamics, the ultimate resolution it affords depends on the spatial specificity of hemodynamics to neuronal activity at a detailed spatial scale, and by the evolution of this specificity over time. Several laminar (≤1 mm spatial resolution) fMRI studies have examined spatial characteristics of the measured hemodynamic signals across cortical depth, in light of understanding or improving the spatial specificity of laminar fMRI. Few studies have examined temporal features of the hemodynamic response across cortical depth. Temporal features of the hemodynamic response offer an additional means to improve the specificity of fMRI, and could help target neuronal processes and neurovascular coupling relationships across laminae, for example by differences in the onset times of the response across cortical depth. In this review, we discuss factors that affect the timing of neuronal and hemodynamic responses across laminae, touching on the neuronal laminar organization, and focusing on the laminar vascular organization. We provide an overview of hemodynamics across the cortical vascular tree based on optical imaging studies, and review temporal aspects of hemodynamics that have been examined across cortical depth in high spatiotemporal resolution fMRI studies. Last, we discuss the limits and potential of high spatiotemporal resolution fMRI to study laminar neurovascular coupling and neuronal processes.
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Affiliation(s)
- Natalia Petridou
- Radiology, University Medical Centre Utrecht, Utrecht, The Netherlands.
| | - Jeroen C W Siero
- Radiology, University Medical Centre Utrecht, Utrecht, The Netherlands; Spinoza Centre for Neuroimaging, Amsterdam, The Netherlands
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23
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Zhu J, Merkle CW, Bernucci MT, Chong SP, Srinivasan VJ. Can OCT Angiography Be Made a Quantitative Blood Measurement Tool? APPLIED SCIENCES-BASEL 2017; 7. [PMID: 30009045 PMCID: PMC6042878 DOI: 10.3390/app7070687] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Optical Coherence Tomography Angiography (OCTA) refers to a powerful class of OCT scanning protocols and algorithms that selectively enhance the imaging of blood vessel lumens, based mainly on the motion and scattering of red blood cells (RBCs). Though OCTA is widely used in clinical and basic science applications for visualization of perfused blood vessels, OCTA is still primarily a qualitative tool. However, more quantitative hemodynamic information would better delineate disease mechanisms, and potentially improve the sensitivity for detecting early stages of disease. Here, we take a broader view of OCTA in the context of microvascular hemodynamics and light scattering. Paying particular attention to the unique challenges presented by capillaries versus larger supplying and draining vessels, we critically assess opportunities and challenges in making OCTA a quantitative tool.
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Affiliation(s)
- Jun Zhu
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA
| | - Conrad W. Merkle
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA
| | - Marcel T. Bernucci
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA
| | - Shau Poh Chong
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA
| | - Vivek J. Srinivasan
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA
- Department of Ophthalmology and Vision Science, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
- Correspondence: ; Tel.: +1-530-752-9277
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24
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You J, Volkow ND, Park K, Zhang Q, Clare K, Du C, Pan Y. Cerebrovascular adaptations to cocaine-induced transient ischemic attacks in the rodent brain. JCI Insight 2017; 2:e90809. [PMID: 28289715 PMCID: PMC5333953 DOI: 10.1172/jci.insight.90809] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 01/24/2017] [Indexed: 12/15/2022] Open
Abstract
Occurrence of transient ischemic attacks (TIA) and cerebral strokes is a recognized risk associated with cocaine abuse. Here, we use a rodent model along with optical imaging to study cocaine-induced TIA and the associated dynamic changes in cerebral blood flow velocity (CBFv) and cerebrovasculature. We show that chronic cocaine exposure in mice resulted in marked cortical hypoperfusion, in significant arterial and venous vasoconstriction, and in a sensitized vascular response to an acute cocaine injection. Starting after 10 days of exposure, an acute cocaine challenge to these mice resulted in a TIA, which presented as hemiparalysis and was associated with an abrupt exacerbation of CBFv. The severity of the TIA correlated with the decreases in cortical CBFv such that the greater the decreases in flow, the longer the TIA duration. The severity of TIA peaked around 17-22 days of cocaine exposure and decreased thereafter in parallel to a reorganization of CBFv from superficial to deep cortical layers, along with an increase in vessel density into these layers. Here, we document for the first time to our knowledge evidence of a TIA in an animal model of chronic cocaine exposure that was associated with profound decreases in CBFv, and we revealed that while the severity of the TIA initially increased with repeated exposures, it subsequently improved in parallel to an increase in the vessel density. This suggests that strategies to accelerate cerebrovascular recovery might be therapeutically beneficial in cocaine abusers.
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Affiliation(s)
- Jiang You
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, USA
| | - Nora D. Volkow
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
| | - Kicheon Park
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, USA
| | - Qiujia Zhang
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, USA
| | - Kevin Clare
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, USA
| | - Congwu Du
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, USA
| | - Yingtian Pan
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, USA
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25
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Baumann B, Woehrer A, Ricken G, Augustin M, Mitter C, Pircher M, Kovacs GG, Hitzenberger CK. Visualization of neuritic plaques in Alzheimer's disease by polarization-sensitive optical coherence microscopy. Sci Rep 2017; 7:43477. [PMID: 28262719 PMCID: PMC5337955 DOI: 10.1038/srep43477] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/24/2017] [Indexed: 12/16/2022] Open
Abstract
One major hallmark of Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA) is the deposition of extracellular senile plaques and vessel wall deposits composed of amyloid-beta (Aβ). In AD, degeneration of neurons is preceded by the formation of Aβ plaques, which show different morphological forms. Most of them are birefringent owing to the parallel arrangement of amyloid fibrils. Here, we present polarization sensitive optical coherence microscopy (PS-OCM) for imaging mature neuritic Aβ plaques based on their birefringent properties. Formalin-fixed, post-mortem brain samples of advanced stage AD patients were investigated. In several cortical brain regions, neuritic Aβ plaques were successfully visualized in tomographic and three-dimensional (3D) images. Cortical grey matter appeared polarization preserving, whereas neuritic plaques caused increased phase retardation. Consistent with the results from PS-OCM imaging, the 3D structure of senile Aβ plaques was computationally modelled for different illumination settings and plaque sizes. Furthermore, the birefringent properties of cortical and meningeal vessel walls in CAA were investigated in selected samples. Significantly increased birefringence was found in smaller vessels. Overall, these results provide evidence that PS-OCM is able to assess amyloidosis based on intrinsic birefringent properties.
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Affiliation(s)
- Bernhard Baumann
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, A-1090, Vienna, Austria
| | - Adelheid Woehrer
- General Hospital and Medical University of Vienna, Institute of Neurology, A-1090, Vienna, Austria
| | - Gerda Ricken
- General Hospital and Medical University of Vienna, Institute of Neurology, A-1090, Vienna, Austria
| | - Marco Augustin
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, A-1090, Vienna, Austria
| | - Christian Mitter
- General Hospital and Medical University of Vienna, Institute of Neurology, A-1090, Vienna, Austria
- General Hospital and Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, A-1090, Vienna, Austria
| | - Michael Pircher
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, A-1090, Vienna, Austria
| | - Gabor G. Kovacs
- General Hospital and Medical University of Vienna, Institute of Neurology, A-1090, Vienna, Austria
| | - Christoph K. Hitzenberger
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, A-1090, Vienna, Austria
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26
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Merkle CW, Leahy C, Srinivasan VJ. Dynamic contrast optical coherence tomography images transit time and quantifies microvascular plasma volume and flow in the retina and choriocapillaris. BIOMEDICAL OPTICS EXPRESS 2016; 7:4289-4312. [PMID: 27867732 PMCID: PMC5102529 DOI: 10.1364/boe.7.004289] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/19/2016] [Accepted: 09/16/2016] [Indexed: 05/18/2023]
Abstract
Despite the prevalence of optical imaging techniques to measure hemodynamics in large retinal vessels, quantitative measurements of retinal capillary and choroidal hemodynamics have traditionally been challenging. Here, a new imaging technique called dynamic contrast optical coherence tomography (DyC-OCT) is applied in the rat eye to study microvascular blood flow in individual retinal and choroidal layers in vivo. DyC-OCT is based on imaging the transit of an intravascular tracer dynamically as it passes through the field-of-view. Hemodynamic parameters can be determined through quantitative analysis of tracer kinetics. In addition to enabling depth-resolved transit time, volume, and flow measurements, the injected tracer also enhances OCT angiograms and enables clear visualization of the choriocapillaris, particularly when combined with a post-processing method for vessel enhancement. DyC-OCT complements conventional OCT angiography through quantification of tracer dynamics, similar to fluorescence angiography, but with the important added benefit of laminar resolution.
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Affiliation(s)
- Conrad W. Merkle
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA
| | - Conor Leahy
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA
| | - Vivek J. Srinivasan
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA
- Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, California, USA
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27
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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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