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Park B, Oh D, Kim J, Kim C. Functional photoacoustic imaging: from nano- and micro- to macro-scale. NANO CONVERGENCE 2023; 10:29. [PMID: 37335405 PMCID: PMC10279631 DOI: 10.1186/s40580-023-00377-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 05/24/2023] [Indexed: 06/21/2023]
Abstract
Functional photoacoustic imaging is a promising biological imaging technique that offers such unique benefits as scalable resolution and imaging depth, as well as the ability to provide functional information. At nanoscale, photoacoustic imaging has provided super-resolution images of the surface light absorption characteristics of materials and of single organelles in cells. At the microscopic and macroscopic scales. photoacoustic imaging techniques have precisely measured and quantified various physiological parameters, such as oxygen saturation, vessel morphology, blood flow, and the metabolic rate of oxygen, in both human and animal subjects. This comprehensive review provides an overview of functional photoacoustic imaging across multiple scales, from nano to macro, and highlights recent advances in technology developments and applications. Finally, the review surveys the future prospects of functional photoacoustic imaging in the biomedical field.
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Affiliation(s)
- Byullee Park
- Departments of Convergence IT Engineering, Mechanical Engineering, and Electrical Engineering, School of Interdisciplinary Bioscience and Bioengineering, Medical Device Innovation Center, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
- Department of Biophysics, Institute of Quantum Biophysics, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Donghyeon Oh
- Departments of Convergence IT Engineering, Mechanical Engineering, and Electrical Engineering, School of Interdisciplinary Bioscience and Bioengineering, Medical Device Innovation Center, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jeesu Kim
- Departments of Cogno-Mechatronics Engineering and Optics and Mechatronics Engineering, College of Nanoscience and Nanotechnology, Pusan National University, Busan, 46241, Republic of Korea.
| | - Chulhong Kim
- Departments of Convergence IT Engineering, Mechanical Engineering, and Electrical Engineering, School of Interdisciplinary Bioscience and Bioengineering, Medical Device Innovation Center, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
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2
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Carmona-Barrón VG, Fernández del Campo IS, Delgado-García JM, De la Fuente AJ, Lopez IP, Merchán MA. Comparing the effects of transcranial alternating current and temporal interference (tTIS) electric stimulation through whole-brain mapping of c-Fos immunoreactivity. Front Neuroanat 2023; 17:1128193. [PMID: 36992795 PMCID: PMC10040600 DOI: 10.3389/fnana.2023.1128193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 02/16/2023] [Indexed: 03/16/2023] Open
Abstract
The analysis of the topography of brain neuromodulation following transcranial alternating current (AC) stimulation is relevant for defining strategies directed to specific nuclei stimulation in patients. Among the different procedures of AC stimulation, temporal interference (tTIS) is a novel method for non-invasive neuromodulation of specific deep brain targets. However, little information is currently available about its tissue effects and its activation topography in in vivo animal models. After a single session (30 min, 0.12 mA) of transcranial alternate current (2,000 Hz; ES/AC group) or tTIS (2,000/2,010 Hz; Es/tTIS group) stimulation, rat brains were explored by whole-brain mapping analysis of c-Fos immunostained serial sections. For this analysis, we used two mapping methods, namely density-to-color processed channels (independent component analysis (ICA) and graphical representation (MATLAB) of morphometrical and densitometrical values obtained by density threshold segmentation. In addition, to assess tissue effects, alternate serial sections were stained for glial fibrillary acidic protein (GFAP), ionized calcium-binding adapter molecule 1 (Iba1), and Nissl. AC stimulation induced a mild superficial increase in c-Fos immunoreactivity. However, tTIS stimulation globally decreased the number of c-Fos-positive neurons and increased blood brain barrier cell immunoreactivity. tTIS also had a stronger effect around the electrode placement area and preserved neuronal activation better in restricted areas of the deep brain (directional stimulation). The enhanced activation of intramural blood vessels’ cells and perivascular astrocytes suggests that low-frequency interference (10 Hz) may also have a trophic effect.
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Affiliation(s)
| | | | | | - Antonio J. De la Fuente
- Institute of Neuroscience of Castilla y Leon (INCYL), University of Salamanca, Salamanca, Spain
| | - Ignacio Plaza Lopez
- Institute of Neuroscience of Castilla y Leon (INCYL), University of Salamanca, Salamanca, Spain
| | - Miguel A. Merchán
- Institute of Neuroscience of Castilla y Leon (INCYL), University of Salamanca, Salamanca, Spain
- *Correspondence: Miguel A. Merchán
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3
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Li D, Humayun L, Vienneau E, Vu T, Yao J. Seeing through the Skin: Photoacoustic Tomography of Skin Vasculature and Beyond. JID INNOVATIONS 2021; 1:100039. [PMID: 34909735 PMCID: PMC8659408 DOI: 10.1016/j.xjidi.2021.100039] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 05/17/2021] [Accepted: 05/28/2021] [Indexed: 12/12/2022] Open
Abstract
Skin diseases are the most common human diseases and manifest in distinct structural and functional changes to skin tissue components such as basal cells, vasculature, and pigmentation. Although biopsy is the standard practice for skin disease diagnosis, it is not sufficient to provide in vivo status of the skin and highly depends on the timing of diagnosis. Noninvasive imaging technologies that can provide structural and functional tissue information in real time would be invaluable for skin disease diagnosis and treatment evaluation. Among the modern medical imaging technologies, photoacoustic (PA) tomography (PAT) shows great promise as an emerging optical imaging modality with high spatial resolution, high imaging speed, deep penetration depth, rich contrast, and inherent sensitivity to functional and molecular information. Over the last decade, PAT has undergone an explosion in technical development and biomedical applications. Particularly, PAT has attracted increasing attention in skin disease diagnosis, providing structural, functional, metabolic, molecular, and histological information. In this concise review, we introduce the principles and imaging capability of various PA skin imaging technologies. We highlight the representative applications in the past decade with a focus on imaging skin vasculature and melanoma. We also envision the critical technical developments necessary to further accelerate the translation of PAT technologies to fundamental skin research and clinical impacts.
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Key Words
- ACD, allergy contact dermatitis
- AR-PAM, acoustic-resolution photoacoustic microscopy
- CSC, cryogen spray cooling
- CSVV, cutaneous small-vessel vasculitis
- CTC, circulating tumor cell
- FDA, Food and Drug Administration
- NIR, near-infrared
- OR-PAM, optical-resolution photoacoustic microscopy
- PA, photoacoustic
- PACT, photoacoustic computed tomography
- PAM, photoacoustic microscopy
- PAT, photoacoustic tomography
- PWS, port-wine stain
- RSOM, raster-scan optoacoustic mesoscopy
- THb, total hemoglobin concentration
- sO2, oxygen saturation of hemoglobin
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Affiliation(s)
- Daiwei Li
- Photoacoustic Imaging Lab, Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
| | - Lucas Humayun
- Photoacoustic Imaging Lab, Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
| | - Emelina Vienneau
- Photoacoustic Imaging Lab, Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
- Department of Biomedical Engineering, School of Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Tri Vu
- Photoacoustic Imaging Lab, Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
| | - Junjie Yao
- Photoacoustic Imaging Lab, Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
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4
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Vu T, DiSpirito A, Li D, Wang Z, Zhu X, Chen M, Jiang L, Zhang D, Luo J, Zhang YS, Zhou Q, Horstmeyer R, Yao J. Deep image prior for undersampling high-speed photoacoustic microscopy. PHOTOACOUSTICS 2021; 22:100266. [PMID: 33898247 PMCID: PMC8056431 DOI: 10.1016/j.pacs.2021.100266] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/15/2021] [Accepted: 03/23/2021] [Indexed: 05/02/2023]
Abstract
Photoacoustic microscopy (PAM) is an emerging imaging method combining light and sound. However, limited by the laser's repetition rate, state-of-the-art high-speed PAM technology often sacrifices spatial sampling density (i.e., undersampling) for increased imaging speed over a large field-of-view. Deep learning (DL) methods have recently been used to improve sparsely sampled PAM images; however, these methods often require time-consuming pre-training and large training dataset with ground truth. Here, we propose the use of deep image prior (DIP) to improve the image quality of undersampled PAM images. Unlike other DL approaches, DIP requires neither pre-training nor fully-sampled ground truth, enabling its flexible and fast implementation on various imaging targets. Our results have demonstrated substantial improvement in PAM images with as few as 1.4 % of the fully sampled pixels on high-speed PAM. Our approach outperforms interpolation, is competitive with pre-trained supervised DL method, and is readily translated to other high-speed, undersampling imaging modalities.
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Affiliation(s)
- Tri Vu
- Photoacoustic Imaging Lab, Duke University, Durham, NC, 27708, USA
| | | | - Daiwei Li
- Photoacoustic Imaging Lab, Duke University, Durham, NC, 27708, USA
| | - Zixuan Wang
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Cambridge, MA, 02139, USA
| | - Xiaoyi Zhu
- Photoacoustic Imaging Lab, Duke University, Durham, NC, 27708, USA
| | - Maomao Chen
- Photoacoustic Imaging Lab, Duke University, Durham, NC, 27708, USA
| | - Laiming Jiang
- Department of Biomedical Engineering and USC Roski Eye Institute, University of Southern California, Los Angeles, CA, 90089, USA
| | - Dong Zhang
- Department of Biomedical Engineering, Tsinghua University, Beijing, 100084, China
| | - Jianwen Luo
- Department of Biomedical Engineering, Tsinghua University, Beijing, 100084, China
| | - Yu Shrike Zhang
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Cambridge, MA, 02139, USA
| | - Qifa Zhou
- Department of Biomedical Engineering and USC Roski Eye Institute, University of Southern California, Los Angeles, CA, 90089, USA
| | | | - Junjie Yao
- Photoacoustic Imaging Lab, Duke University, Durham, NC, 27708, USA
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Ravina K, Lin L, Liu CY, Thomas D, Hasson D, Wang LV, Russin JJ. Prospects of Photo- and Thermoacoustic Imaging in Neurosurgery. Neurosurgery 2020; 87:11-24. [PMID: 31620798 DOI: 10.1093/neuros/nyz420] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 07/25/2019] [Indexed: 12/25/2022] Open
Abstract
The evolution of neurosurgery has been, and continues to be, closely associated with innovations in technology. Modern neurosurgery is wed to imaging technology and the future promises even more dependence on anatomic and, perhaps more importantly, functional imaging. The photoacoustic phenomenon was described nearly 140 yr ago; however, biomedical applications for this technology have only recently received significant attention. Light-based photoacoustic and microwave-based thermoacoustic technologies represent novel biomedical imaging modalities with broad application potential within and beyond neurosurgery. These technologies offer excellent imaging resolution while generally considered safer, more portable, versatile, and convenient than current imaging technologies. In this review, we summarize the current state of knowledge regarding photoacoustic and thermoacoustic imaging and their potential impact on the field of neurosurgery.
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Affiliation(s)
- Kristine Ravina
- Neurorestoration Center, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Li Lin
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, Pasadena, California.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Charles Y Liu
- Neurorestoration Center, Keck School of Medicine, University of Southern California, Los Angeles, California.,Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California.,Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, California.,Tianqiao and Chrissy Chen Brain-machine Interface Center, California Institute of Technology, Pasadena, California
| | - Debi Thomas
- Department of Surgery, University of California Davis, Davis, California
| | - Denise Hasson
- Division of Critical Care Medicine, Cincinnati Children's Hospital, Cincinnati, Ohio
| | - Lihong V Wang
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, Pasadena, California
| | - Jonathan J Russin
- Neurorestoration Center, Keck School of Medicine, University of Southern California, Los Angeles, California.,Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
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He Y, Wang M, Yu X. High spatiotemporal vessel-specific hemodynamic mapping with multi-echo single-vessel fMRI. J Cereb Blood Flow Metab 2020; 40:2098-2114. [PMID: 31696765 PMCID: PMC7786852 DOI: 10.1177/0271678x19886240] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
High-resolution fMRI enables noninvasive mapping of the hemodynamic responses from individual penetrating vessels in animal brains. Here, a 2D multi-echo single-vessel fMRI (MESV-fMRI) method has been developed to map the fMRI signal from arterioles and venules with a 100 ms sampling rate at multiple echo times (TE, 3-30 ms) and short acquisition windows (<1 ms). The T2*-weighted signal shows the increased extravascular effect on venule voxels as a function of TE. In contrast, the arteriole voxels show an increased fMRI signal with earlier onset than venules voxels at the short TE (3 ms) with increased blood inflow and volume effects. MESV-fMRI enables vessel-specific T2* mapping and presents T2*-based fMRI time courses with higher contrast-to-noise ratios (CNRs) than the T2*-weighted fMRI signal at a given TE. The vessel-specific T2* mapping also allows semi-quantitative estimation of the oxygen saturation levels (Y) and their changes (ΔY) at a given blood volume fraction upon neuronal activation. The MESV-fMRI method enables vessel-specific T2* measurements with high spatiotemporal resolution for better modeling of the fMRI signal based on the hemodynamic parameters.
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Affiliation(s)
- Yi He
- Translational Neuroimaging and Neural Control Group, High Field Magnetic Resonance Department, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Graduate Training Centre of Neuroscience, International Max Planck Research School, University of Tuebingen, Tuebingen, Germany.,Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Maosen Wang
- Translational Neuroimaging and Neural Control Group, High Field Magnetic Resonance Department, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Graduate Training Centre of Neuroscience, International Max Planck Research School, University of Tuebingen, Tuebingen, Germany
| | - Xin Yu
- Translational Neuroimaging and Neural Control Group, High Field Magnetic Resonance Department, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
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7
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Kang J, Zhang HK, Kadam SD, Fedorko J, Valentine H, Malla AP, Yan P, Harraz MM, Kang JU, Rahmim A, Gjedde A, Loew LM, Wong DF, Boctor EM. Transcranial Recording of Electrophysiological Neural Activity in the Rodent Brain in vivo Using Functional Photoacoustic Imaging of Near-Infrared Voltage-Sensitive Dye. Front Neurosci 2019; 13:579. [PMID: 31447622 PMCID: PMC6696882 DOI: 10.3389/fnins.2019.00579] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 05/22/2019] [Indexed: 12/27/2022] Open
Abstract
Minimally-invasive monitoring of electrophysiological neural activities in real-time-that enables quantification of neural functions without a need for invasive craniotomy and the longer time constants of fMRI and PET-presents a very challenging yet significant task for neuroimaging. In this paper, we present in vivo functional PA (fPA) imaging of chemoconvulsant rat seizure model with intact scalp using a fluorescence quenching-based cyanine voltage-sensitive dye (VSD) characterized by a lipid vesicle model mimicking different levels of membrane potential variation. The framework also involves use of a near-infrared VSD delivered through the blood-brain barrier (BBB), opened by pharmacological modulation of adenosine receptor signaling. Our normalized time-frequency analysis presented in vivo VSD response in the seizure group significantly distinguishable from those of the control groups at sub-mm spatial resolution. Electroencephalogram (EEG) recording confirmed the changes of severity and frequency of brain activities, induced by chemoconvulsant seizures of the rat brain. The findings demonstrate that the near-infrared fPA VSD imaging is a promising tool for in vivo recording of brain activities through intact scalp, which would pave a way to its future translation in real time human brain imaging.
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Affiliation(s)
- Jeeun Kang
- Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, United States
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, United States
| | - Haichong K. Zhang
- Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, United States
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, United States
| | - Shilpa D. Kadam
- Department of Neurology, Hugo W. Moser Research Institute at Kennedy Krieger, Johns Hopkins Medical Institutions, Baltimore, MD, United States
| | - Julie Fedorko
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, United States
| | - Heather Valentine
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, United States
| | - Adarsha P. Malla
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, United States
| | - Ping Yan
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut Health, Farmington, CT, United States
| | - Maged M. Harraz
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, United States
| | - Jin U. Kang
- Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Arman Rahmim
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, United States
| | - Albert Gjedde
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, United States
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Leslie M. Loew
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut Health, Farmington, CT, United States
| | - Dean F. Wong
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, United States
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, United States
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, United States
- Department of Neurology, Johns Hopkins Medical Institutions, Baltimore, MD, United States
- Department of Environmental Sciences and Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Emad M. Boctor
- Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, United States
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, United States
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Ding N, Liu X, Chen N, Jiang J, Zhao H, Li Z, Zhang J, Liu C. Lack of association between acupoint sensitization and microcirculatory structural changes in a mouse model of knee osteoarthritis: A pilot study. JOURNAL OF BIOPHOTONICS 2019; 12:e201800458. [PMID: 30740905 PMCID: PMC7065615 DOI: 10.1002/jbio.201800458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 02/01/2019] [Accepted: 02/06/2019] [Indexed: 05/05/2023]
Abstract
As a stimulating point in acupuncture, acupoint has unique microcirculatory features, and its dynamics vary greatly depending on health status. Acupoint sensitization is defined as the transformation of an acupoint from a "silenced status" (healthy) to an "activated status" (disease). Our previous study demonstrated that acupoint sensitization is associated with an increase in the level of local blood perfusion. However, the structural changes in microcirculation during acupoint sensitization have yet to be elucidated because the high-resolution microcirculation imaging of acupoints has been difficult to obtain. In this study, the structural changes in microcirculation at the Zusanli (ST36), Yanglingquan (GB34) and nonacupoint sites on days 0, 7 and 21 were dynamically observed during acupoint sensitization in an experimental knee osteoarthritis mouse model by using optical-resolution photoacoustic microscopy. The results showed that no significant differences in microvessel density, the distribution of vessel diameters or vascular tortuosity were observed at the GB34, ST36 or nonacupoint sites among days 0, 7 and 21. We proposed that acupoint sensitization may not be associated with the structural changes in microcirculation and that the microcirculatory changes during acupoint sensitization are more likely to be functional. The functional characteristics of the sensitized acupoints warrant further investigation.
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Affiliation(s)
- Ning Ding
- School of Acupuncture, Moxibustion and TuinaBeijing University of Chinese MedicineBeijingChina
| | - Xiaoxiao Liu
- School of Acupuncture, Moxibustion and TuinaBeijing University of Chinese MedicineBeijingChina
| | - Ningbo Chen
- Research Laboratory for Biomedical Optics and Molecular ImagingShenzhen Institutes of Advanced Technology, Chinese Academy of SciencesShenzhenChina
- School of Mechanical and Electrical EngineeringGuangzhou UniversityGuangzhouChina
| | - Jing Jiang
- School of NursingBeijing University of Chinese MedicineBeijingChina
| | - Huangxuan Zhao
- Research Laboratory for Biomedical Optics and Molecular ImagingShenzhen Institutes of Advanced Technology, Chinese Academy of SciencesShenzhenChina
- School of Biomedical EngineeringCapital Medical UniversityBeijingChina
| | - Zhigang Li
- School of Acupuncture, Moxibustion and TuinaBeijing University of Chinese MedicineBeijingChina
| | - Jianhui Zhang
- School of Mechanical and Electrical EngineeringGuangzhou UniversityGuangzhouChina
| | - Chengbo Liu
- Research Laboratory for Biomedical Optics and Molecular ImagingShenzhen Institutes of Advanced Technology, Chinese Academy of SciencesShenzhenChina
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Li M, Tang Y, Yao J. Photoacoustic tomography of blood oxygenation: A mini review. PHOTOACOUSTICS 2018; 10:65-73. [PMID: 29988848 PMCID: PMC6033062 DOI: 10.1016/j.pacs.2018.05.001] [Citation(s) in RCA: 172] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 05/24/2018] [Accepted: 05/28/2018] [Indexed: 05/04/2023]
Abstract
Photoacoustic tomography (PAT) is a hybrid imaging modality that combines rich contrast of optical excitation and deep penetration of ultrasound detection. With its unique optical absorption contrast mechanism, PAT is inherently sensitive to the functional and molecular information of biological tissues, and thus has been widely used in preclinical and clinical studies. Among many functional capabilities of PAT, measuring blood oxygenation is arguably one of the most important applications, and has been widely performed in photoacoustic studies of brain functions, tumor hypoxia, wound healing, and cancer therapy. Yet, the complex optical conditions of biological tissues, especially the strong wavelength-dependent optical attenuation, have long hurdled the PAT measurement of blood oxygenation at depths beyond a few millimeters. A variety of PAT methods have been developed to improve the accuracy of blood oxygenation measurement, using novel laser illumination schemes, oxygen-sensitive fluorescent dyes, comprehensive mathematic models, or prior information provided by complementary imaging modalities. These novel methods have made exciting progress, while several challenges remain. This concise review aims to introduce the recent developments in photoacoustic blood oxygenation measurement, compare each method's advantages and limitations, highlight their representative applications, and discuss the remaining challenges for future advances.
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Affiliation(s)
| | | | - Junjie Yao
- Photoacoustic Imaging Laboratory, Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
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10
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Tan MJ, Pan HC, Tan HR, Chai JW, Lim QF, Wong TI, Zhou X, Hong ZY, Liao LD, Kong KV. Flexible Modulation of CO-Release Using Various Nuclearity of Metal Carbonyl Clusters on Graphene Oxide for Stroke Remediation. Adv Healthc Mater 2018; 7. [PMID: 29327505 DOI: 10.1002/adhm.201701113] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/29/2017] [Indexed: 11/11/2022]
Abstract
Utilizing the size-dependent adsorption properties of ruthenium carbonyl clusters (Ru-carbon monoxide (CO)) onto graphene oxide (GO), a facile CO-release platform for in situ vasodilation as a treatment for stroke-related vascular diseases is developed. The rate and amount of formation of the CO-release-active RuII (CO)2 species can be modulated by a simple mixing procedure at room temperature. The subsequent thermally induced oxidation of RuII (CO)2 to RuO2 on the GO surface results in the release of CO. Further modulation of thermal and CO-release properties can be achieved via a hybridization of medium- and high-nuclearity of Ru-CO clusters that produces a RuO2 /RuII (CO)2 /6 Ru-CO-GO composite, where 6 Ru-CO-GO provides a photothermally activated reservoir of RuII (CO)2 species and the combined infrared absorption properties of GO and RuO2 provides photothermal response for in situ CO-release. The RuO2 /RuII (CO)2 /6 Ru-CO-GO composite does not produce any cytotoxicity and the efficacy of the composite is further demonstrated in a cortical photothrombotic ischemia rat model.
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Affiliation(s)
- Mein Jin Tan
- Institute of Materials Research and Engineering; A*STAR; 2 Fusionopolis Way. Innovis, #08-03 138634 Singapore
| | - Han-Chi Pan
- Institute of Biomedical Engineering and Nanomedicine; National Health Research Institutes; 35 Keyan Road Zhunan Miaoli County 35053 Taiwan
| | - Hui Ru Tan
- Institute of Materials Research and Engineering; A*STAR; 2 Fusionopolis Way. Innovis, #08-03 138634 Singapore
| | - Jian Wei Chai
- Institute of Materials Research and Engineering; A*STAR; 2 Fusionopolis Way. Innovis, #08-03 138634 Singapore
| | - Qi Feng Lim
- Institute of Materials Research and Engineering; A*STAR; 2 Fusionopolis Way. Innovis, #08-03 138634 Singapore
| | - Ten It Wong
- Institute of Materials Research and Engineering; A*STAR; 2 Fusionopolis Way. Innovis, #08-03 138634 Singapore
| | - Xiaodong Zhou
- Institute of Materials Research and Engineering; A*STAR; 2 Fusionopolis Way. Innovis, #08-03 138634 Singapore
| | - Zi-Yao Hong
- Department of Chemistry; National Taiwan University; Taipei 10617 Taiwan
| | - Lun-De Liao
- Institute of Biomedical Engineering and Nanomedicine; National Health Research Institutes; 35 Keyan Road Zhunan Miaoli County 35053 Taiwan
| | - Kien Voon Kong
- Department of Chemistry; National Taiwan University; Taipei 10617 Taiwan
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Urban A, Golgher L, Brunner C, Gdalyahu A, Har-Gil H, Kain D, Montaldo G, Sironi L, Blinder P. Understanding the neurovascular unit at multiple scales: Advantages and limitations of multi-photon and functional ultrasound imaging. Adv Drug Deliv Rev 2017; 119:73-100. [PMID: 28778714 DOI: 10.1016/j.addr.2017.07.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 07/17/2017] [Accepted: 07/22/2017] [Indexed: 02/07/2023]
Abstract
Developing efficient brain imaging technologies by combining a high spatiotemporal resolution and a large penetration depth is a key step for better understanding the neurovascular interface that emerges as a main pathway to neurodegeneration in many pathologies such as dementia. This review focuses on the advances in two complementary techniques: multi-photon laser scanning microscopy (MPLSM) and functional ultrasound imaging (fUSi). MPLSM has become the gold standard for in vivo imaging of cellular dynamics and morphology, together with cerebral blood flow. fUSi is an innovative imaging modality based on Doppler ultrasound, capable of recording vascular brain activity over large scales (i.e., tens of cubic millimeters) at unprecedented spatial and temporal resolution for such volumes (up to 10μm pixel size at 10kHz). By merging these two technologies, researchers may have access to a more detailed view of the various processes taking place at the neurovascular interface. MPLSM and fUSi are also good candidates for addressing the major challenge of real-time delivery, monitoring, and in vivo evaluation of drugs in neuronal tissue.
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Affiliation(s)
- Alan Urban
- Neuroelectronics Research Flanders, Leuven, Belgium; VIB, Leuven, Belgium and/or IMEC, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium; Neurobiology Dept., Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Lior Golgher
- Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
| | - Clément Brunner
- Neuroelectronics Research Flanders, Leuven, Belgium; VIB, Leuven, Belgium and/or IMEC, Leuven, Belgium
| | - Amos Gdalyahu
- Neurobiology Dept., Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Hagai Har-Gil
- Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
| | - David Kain
- Neurobiology Dept., Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Gabriel Montaldo
- Neuroelectronics Research Flanders, Leuven, Belgium; VIB, Leuven, Belgium and/or IMEC, Leuven, Belgium
| | - Laura Sironi
- Physics Dept., Universita degli Studi di Milano Bicocca, Italy
| | - Pablo Blinder
- Neurobiology Dept., Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel; Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel.
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12
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Li Q, Li L, Yu T, Zhao Q, Zhou C, Chai X. Vascular tree extraction for photoacoustic microscopy and imaging of cat primary visual cortex. JOURNAL OF BIOPHOTONICS 2017; 10:780-791. [PMID: 27545832 DOI: 10.1002/jbio.201600150] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/21/2016] [Accepted: 08/05/2016] [Indexed: 06/06/2023]
Abstract
A vascular tree extraction algorithm is proposed to automatically extract independent and complete vascular trees from both background and other crossed vascular trees for photoacoustic microscopy (PAM) imaging. Extracted parameters include vascular tree centerline, diameters, boundaries and three-dimensional (3-D) direction along the tree. Based on the concept of blood vessel tracking, the proposed algorithm extracts complete vascular trees by utilizing a ray casting framework to realize functions which includes vessel direction estimation, vessel branching detection and vessel crossover point detection. An optical-resolution PAM (OR-PAM) system is set up and the acquired images of cat primary visual cortex are used to demonstrate the effectiveness of the proposed algorithm. The proposed algorithm successfully extracts a complete and complex arteriole tree composed of multiple loop structures. Most branches and vessel crossovers in the arteriole tree are accurately extracted. Accuray of the algorithm is further tested on phantom images and real OR-PAM vascular tree images. As the extracted parameters are directly related with monitoring hemodynamic responses at the level of vascular trees, the proposed algorithm may facilitate the application of PAM on studies of neurovascular coupling and related brain functions and diseases. OR-PAM maximum intensity projection image of cat primary visual cortex.
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Affiliation(s)
- Qian Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, 200240, Shanghai, China
| | - Lin Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, 200240, Shanghai, China
| | - Tianhao Yu
- School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, 200240, Shanghai, China
| | - Qingliang Zhao
- School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, 200240, Shanghai, China
| | - Chuanqing Zhou
- School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, 200240, Shanghai, China
| | - Xinyu Chai
- School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, 200240, Shanghai, China
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13
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Gottschalk S, Fehm TF, Deán-Ben XL, Tsytsarev V, Razansky D. Correlation between volumetric oxygenation responses and electrophysiology identifies deep thalamocortical activity during epileptic seizures. NEUROPHOTONICS 2017; 4:011007. [PMID: 27725948 PMCID: PMC5050254 DOI: 10.1117/1.nph.4.1.011007] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 09/13/2016] [Indexed: 05/05/2023]
Abstract
Visualization of whole brain activity during epileptic seizures is essential for both fundamental research into the disease mechanisms and the development of efficient treatment strategies. It has been previously discussed that pathological synchronization originating from cortical areas may reinforce backpropagating signaling from the thalamic neurons, leading to massive seizures through enhancement of high frequency neural activity in the thalamocortical loop. However, the study of deep brain neural activity is challenging with the existing functional neuroimaging methods due to lack of adequate spatiotemporal resolution or otherwise insufficient penetration into subcortical areas. To investigate the role of thalamocortical activity during epileptic seizures, we developed a new functional neuroimaging framework based on spatiotemporal correlation of volumetric optoacoustic hemodynamic responses with the concurrent electroencephalogram recordings and anatomical brain landmarks. The method is shown to be capable of accurate three-dimensional mapping of the onset, spread, and termination of the epileptiform events in a 4-aminopyridine acute model of focal epilepsy. Our study is the first to demonstrate entirely noninvasive real-time visualization of synchronized epileptic foci in the whole mouse brain, including the neocortex and subcortical structures, thus opening new vistas in systematic studies toward the understanding of brain signaling and the origins of neurological disorders.
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Affiliation(s)
- Sven Gottschalk
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - Thomas Felix Fehm
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
- Technical University of Munich, Faculty of Medicine, Ismaninger Str. 22, 81675 Munich, Germany
| | - Xose Luís Deán-Ben
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - Vassiliy Tsytsarev
- University of Maryland School of Medicine, Department of Anatomy and Neurobiology, 20 Penn Street, HSF II, Baltimore, Maryland 21201, United States
| | - Daniel Razansky
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
- Technical University of Munich, Faculty of Medicine, Ismaninger Str. 22, 81675 Munich, Germany
- Address all correspondence to: Daniel Razansky, E-mail:
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14
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Jiang B, Yang X, Luo Q. Reflection-mode Bessel-beam photoacoustic microscopy for in vivo imaging of cerebral capillaries. OPTICS EXPRESS 2016; 24:20167-76. [PMID: 27607624 DOI: 10.1364/oe.24.020167] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
A reflection-mode Bessel-beam photoacoustic microscope (BB-PAM) is developed for the in vivo imaging of cerebral capillaries with extended depth of field (DoF). The non-diffraction characteristic of Bessel beams means that a larger DoF can be expected in the PAM compared to that using a Gaussian beam (GB). In our system, we generate the Bessel beam using an axicon and an annular mask. The lateral resolution of the system is estimated to be 1.6 μm. The DoF is measured to be 483 μm, and this is verified by imaging a carbon fiber network. The DoF of BB-PAM is about 7 times that of a GB-PAM. The cerebral vasculature of an open-skull mouse is imaged using the developed BB-PAM to demonstrate its in vivo imaging capability and advantages over GB-PAM.
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15
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Guhathakurta D, Dutta A. Computational Pipeline for NIRS-EEG Joint Imaging of tDCS-Evoked Cerebral Responses-An Application in Ischemic Stroke. Front Neurosci 2016; 10:261. [PMID: 27378836 PMCID: PMC4913108 DOI: 10.3389/fnins.2016.00261] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/23/2016] [Indexed: 12/22/2022] Open
Abstract
Transcranial direct current stimulation (tDCS) modulates cortical neural activity and hemodynamics. Electrophysiological methods (electroencephalography-EEG) measure neural activity while optical methods (near-infrared spectroscopy-NIRS) measure hemodynamics coupled through neurovascular coupling (NVC). Assessment of NVC requires development of NIRS-EEG joint-imaging sensor montages that are sensitive to the tDCS affected brain areas. In this methods paper, we present a software pipeline incorporating freely available software tools that can be used to target vascular territories with tDCS and develop a NIRS-EEG probe for joint imaging of tDCS-evoked responses. We apply this software pipeline to target primarily the outer convexity of the brain territory (superficial divisions) of the middle cerebral artery (MCA). We then present a computational method based on Empirical Mode Decomposition of NIRS and EEG time series into a set of intrinsic mode functions (IMFs), and then perform a cross-correlation analysis on those IMFs from NIRS and EEG signals to model NVC at the lesional and contralesional hemispheres of an ischemic stroke patient. For the contralesional hemisphere, a strong positive correlation between IMFs of regional cerebral hemoglobin oxygen saturation and the log-transformed mean-power time-series of IMFs for EEG with a lag of about -15 s was found after a cumulative 550 s stimulation of anodal tDCS. It is postulated that system identification, for example using a continuous-time autoregressive model, of this coupling relation under tDCS perturbation may provide spatiotemporal discriminatory features for the identification of ischemia. Furthermore, portable NIRS-EEG joint imaging can be incorporated into brain computer interfaces to monitor tDCS-facilitated neurointervention as well as cortical reorganization.
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Affiliation(s)
| | - Anirban Dutta
- Department of Psychology and Neurosciences, IfADo - Leibniz Research Centre for Working Environment and Human Factors Dortmund, Germany
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16
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Zhou Y, Yao J, Wang LV. Tutorial on photoacoustic tomography. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:61007. [PMID: 27086868 PMCID: PMC4834026 DOI: 10.1117/1.jbo.21.6.061007] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/22/2016] [Indexed: 05/18/2023]
Abstract
Photoacoustic tomography (PAT) has become one of the fastest growing fields in biomedical optics. Unlike pure optical imaging, such as confocal microscopy and two-photon microscopy, PAT employs acoustic detection to image optical absorption contrast with high-resolution deep into scattering tissue. So far, PAT has been widely used for multiscale anatomical, functional, and molecular imaging of biological tissues. We focus on PAT’s basic principles, major implementations, imaging contrasts, and recent applications.
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Affiliation(s)
- Yong Zhou
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, Campus Box 1097, St. Louis, Missouri 63130, United States
| | - Junjie Yao
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, Campus Box 1097, St. Louis, Missouri 63130, United States
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, Campus Box 1097, St. Louis, Missouri 63130, United States
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17
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Abstract
Photoacoustic tomography (PAT) combines rich optical absorption contrast with the high spatial resolution of ultrasound at depths in tissue. The high scalability of PAT has enabled anatomical imaging of biological structures ranging from organelles to organs. The inherent functional and molecular imaging capabilities of PAT have further allowed it to measure important physiological parameters and track critical cellular activities. Integration of PAT with other imaging technologies provides complementary capabilities and can potentially accelerate the clinical translation of PAT.
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Affiliation(s)
- Junjie Yao
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, MO, USA
| | - Jun Xia
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, MO, USA Department of Biomedical Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Lihong V Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, MO, USA
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18
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Ultrasound-aided Multi-parametric Photoacoustic Microscopy of the Mouse Brain. Sci Rep 2015; 5:18775. [PMID: 26688368 PMCID: PMC4685318 DOI: 10.1038/srep18775] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 11/16/2015] [Indexed: 12/24/2022] Open
Abstract
High-resolution quantitative imaging of cerebral oxygen metabolism in mice is crucial for understanding brain functions and formulating new strategies to treat neurological disorders, but remains a challenge. Here, we report on our newly developed ultrasound-aided multi-parametric photoacoustic microscopy (PAM), which enables simultaneous quantification of the total concentration of hemoglobin (CHb), the oxygen saturation of hemoglobin (sO2), and cerebral blood flow (CBF) at the microscopic level and through the intact mouse skull. The three-dimensional skull and vascular anatomies delineated by the dual-contrast (i.e., ultrasonic and photoacoustic) system provide important guidance for dynamically focused contour scan and vessel orientation-dependent correction of CBF, respectively. Moreover, bi-directional raster scan allows determining the direction of blood flow in individual vessels. Capable of imaging all three hemodynamic parameters at the same spatiotemporal scale, our ultrasound-aided PAM fills a critical gap in preclinical neuroimaging and lays the foundation for high-resolution mapping of the cerebral metabolic rate of oxygen (CMRO2)-a quantitative index of cerebral oxygen metabolism. This technical innovation is expected to shed new light on the mechanism and treatment of a broad spectrum of neurological disorders, including Alzheimer's disease and ischemic stroke.
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19
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Xia J, Yao J, Wang LV. Photoacoustic tomography: principles and advances. ELECTROMAGNETIC WAVES (CAMBRIDGE, MASS.) 2015; 147:1-22. [PMID: 25642127 PMCID: PMC4311576 DOI: 10.2528/pier14032303] [Citation(s) in RCA: 297] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Photoacoustic tomography (PAT) is an emerging imaging modality that shows great potential for preclinical research and clinical practice. As a hybrid technique, PAT is based on the acoustic detection of optical absorption from either endogenous chromophores, such as oxy-hemoglobin and deoxy-hemoglobin, or exogenous contrast agents, such as organic dyes and nanoparticles. Because ultrasound scatters much less than light in tissue, PAT generates high-resolution images in both the optical ballistic and diffusive regimes. Over the past decade, the photoacoustic technique has been evolving rapidly, leading to a variety of exciting discoveries and applications. This review covers the basic principles of PAT and its different implementations. Strengths of PAT are highlighted, along with the most recent imaging results.
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Affiliation(s)
- Jun Xia
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, USA
| | - Junjie Yao
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, USA
| | - Lihong V. Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, USA
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20
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Abstract
AbstractSince its first demonstration of functional imaging in small animals about a decade ago, photoacoustic tomography (PAT) has quickly become one of the fastest growing biomedical imaging modalities. Combining optical excitation with acoustic detection, PAT can provide detailed images of tissues deep in the body. While PAT technology continues to improve significantly, substantial efforts have also been made to develop multimodal PAT systems. These systems not only provide complementary information for more comprehensive characterization of tissue, they also generate data that can be used to further improve PAT reconstruction. This review will present current progress in multimodal PAT imaging, focusing on the technical aspects of integration and its applications in biomedicine.
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21
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Yao J, Wang LV. Sensitivity of photoacoustic microscopy. PHOTOACOUSTICS 2014; 2:87-101. [PMID: 25302158 PMCID: PMC4182819 DOI: 10.1016/j.pacs.2014.04.002] [Citation(s) in RCA: 211] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 04/12/2014] [Indexed: 05/03/2023]
Abstract
Building on its high spatial resolution, deep penetration depth and excellent image contrast, 3D photoacoustic microscopy (PAM) has grown tremendously since its first publication in 2005. Integrating optical excitation and acoustic detection, PAM has broken through both the optical diffusion and optical diffraction limits. PAM has 100% relative sensitivity to optical absorption (i.e., a given percentage change in the optical absorption coefficient yields the same percentage change in the photoacoustic amplitude), and its ultimate detection sensitivity is limited only by thermal noise. Focusing on the engineering aspects of PAM, this Review discusses the detection sensitivity of PAM, compares the detection efficiency of different PAM designs, and summarizes the imaging performance of various endogenous and exogenous contrast agents. It then describes representative PAM applications with high detection sensitivity, and outlines paths to further improvement.
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Affiliation(s)
| | - Lihong V. Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
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22
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Yao J, Wang LV. Photoacoustic Brain Imaging: from Microscopic to Macroscopic Scales. NEUROPHOTONICS 2014; 1:1877516. [PMID: 25401121 PMCID: PMC4232215 DOI: 10.1117/1.nph.1.1.011003] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 03/28/2014] [Accepted: 03/31/2014] [Indexed: 05/12/2023]
Abstract
Human brain mapping has become one of the most exciting contemporary research areas, with major breakthroughs expected in the following decades. Modern brain imaging techniques have allowed neuroscientists to gather a wealth of anatomic and functional information about the brain. Among these techniques, by virtue of its rich optical absorption contrast, high spatial and temporal resolutions, and deep penetration, photoacoustic tomography (PAT) has attracted more and more attention, and is playing an increasingly important role in brain studies. In particular, PAT complements other brain imaging modalities by providing high-resolution functional and metabolic imaging. More importantly, PAT's unique scalability enables scrutinizing the brain at both microscopic and macroscopic scales, using the same imaging contrast. In this Review, we present the state-of-the-art PAT techniques for brain imaging, summarize representative neuroscience applications, outline the technical challenges in translating PAT to human brain imaging, and envision potential technological deliverables.
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Affiliation(s)
- Junjie Yao
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130
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23
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Wang H, Yang X, Liu Y, Jiang B, Luo Q. Reflection-mode optical-resolution photoacoustic microscopy based on a reflective objective. OPTICS EXPRESS 2013; 21:24210-8. [PMID: 24104331 DOI: 10.1364/oe.21.024210] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We developed a new reflection-mode optical-resolution photoacoustic microscopy (OR-PAM) based on the cooperation of a reflective objective and an ultrasonic transducer. The reflective objective is used to produce nearly diffraction-limited optical focusing, and the excited ultrasound waves are then directly detected by an ultrasonic transducer that was placed in the central cone of the objective. This new design avoids the coupling between optical focusing and ultrasound transmission in the reflection mode. Moreover, the proposed system is able to provide lateral resolution of 1.2 μm at 580 nm, penetration depth of 0.9 mm in biological tissues, and a work distance of 6.0 mm. We present in vivo imaging of the microvasculature in mouse ears and in vitro imaging of red blood cells (RBCs), which demonstrate the capability of the system to study microcirculation.
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24
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Yao J, Wang LV. Photoacoustic Microscopy. LASER & PHOTONICS REVIEWS 2013; 7:10.1002/lpor.201200060. [PMID: 24416085 PMCID: PMC3887369 DOI: 10.1002/lpor.201200060] [Citation(s) in RCA: 267] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 11/02/2012] [Indexed: 05/13/2023]
Abstract
Photoacoustic microscopy (PAM) is a hybrid in vivo imaging technique that acoustically detects optical contrast via the photoacoustic effect. Unlike pure optical microscopic techniques, PAM takes advantage of the weak acoustic scattering in tissue and thus breaks through the optical diffusion limit (~1 mm in soft tissue). With its excellent scalability, PAM can provide high-resolution images at desired maximum imaging depths up to a few millimeters. Compared with backscattering-based confocal microscopy and optical coherence tomography, PAM provides absorption contrast instead of scattering contrast. Furthermore, PAM can image more molecules, endogenous or exogenous, at their absorbing wavelengths than fluorescence-based methods, such as wide-field, confocal, and multi-photon microscopy. Most importantly, PAM can simultaneously image anatomical, functional, molecular, flow dynamic and metabolic contrasts in vivo. Focusing on state-of-the-art developments in PAM, this Review discusses the key features of PAM implementations and their applications in biomedical studies.
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Affiliation(s)
- Junjie Yao
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Lihong V. Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
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25
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Hu S, Wang L. Optical-resolution photoacoustic microscopy: auscultation of biological systems at the cellular level. Biophys J 2013; 105:841-7. [PMID: 23972836 PMCID: PMC3752103 DOI: 10.1016/j.bpj.2013.07.017] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 06/16/2013] [Accepted: 07/12/2013] [Indexed: 11/19/2022] Open
Abstract
Photoacoustic microscopy (PAM) offers unprecedented sensitivity to optical absorption and opens a new window to study biological systems at multiple length- and timescales. In particular, optical-resolution PAM (OR-PAM) has pushed the technical envelope to submicron length scales and millisecond timescales. Here, we review the state of the art of OR-PAM in biophysical research. With properly chosen optical wavelengths, OR-PAM can spectrally differentiate a variety of endogenous and exogenous chromophores, unveiling the anatomical, functional, metabolic, and molecular information of biological systems. Newly uncovered contrast mechanisms of linear dichroism and Förster resonance energy transfer further distinguish OR-PAM. Integrating multiple contrasts and advanced scanning mechanisms has capacitated OR-PAM to comprehensively interrogate biological systems at the cellular level in real time. Two future directions are discussed, where OR-PAM holds the potential to translate basic biophysical research into clinical healthcare.
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Affiliation(s)
- Song Hu
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Lihong V. Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri
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26
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Song W, Wei Q, Feng L, Sarthy V, Jiao S, Liu X, Zhang HF. Multimodal photoacoustic ophthalmoscopy in mouse. JOURNAL OF BIOPHOTONICS 2013; 6:505-512. [PMID: 22649053 PMCID: PMC3986594 DOI: 10.1002/jbio.201200061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 04/29/2012] [Accepted: 05/01/2012] [Indexed: 05/04/2023]
Abstract
Photoacoustic ophthalmoscopy (PAOM) is a novel imaging technology that measures optical absorption in the retina. The capability of PAOM can be further enhanced if it could image mouse eyes, because mouse models are widely used for various retinal diseases. The challenges in achieving high-quality imaging of mouse retina, however, come from the much smaller eyeball size. Here, we report an optimized imaging system, which integrates PAOM, spectral-domain optical coherence tomography (SD-OCT), and autofluorescence-scanning laser ophthalmoscopy (AF-SLO), for mouse eyes. Its multimodal capability was demonstrated by imaging transgenic Nrl-GFP mice that express green fluorescent protein (GFP) in photoreceptors. SD-OCT provided guidance of optical alignment for PAOM and AF-SLO, and complementary contrast with high depth-resolution retinal cross sections. PAOM visualized the retinal vasculature and retinal pigment epithelium melanin, and AF-SLO measured GFP-expressing in retinal photoreceptors. The in vivo imaging results were verified by histology and confocal microscopy.
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Affiliation(s)
- Wei Song
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd., Evanston IL 60208, USA
- Department of Physics, Harbin Institute of Technology, 92 West Da-Zhi Street Nangang District, Harbin, Heilongjiang, P.R. China 150080
| | - Qing Wei
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd., Evanston IL 60208, USA
| | - Liang Feng
- Department of Ophthalmology, Northwestern University, 645 North Michigan Ave., Chicago IL 60611, USA
| | - Vijay Sarthy
- Department of Ophthalmology, Northwestern University, 645 North Michigan Ave., Chicago IL 60611, USA
| | - Shuliang Jiao
- Department of Ophthalmology, University of Southern California, 1450 San Pablo Street, Los Angeles CA 90033, USA
| | - Xiaorong Liu
- Department of Ophthalmology, Northwestern University, 645 North Michigan Ave., Chicago IL 60611, USA
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd., Evanston IL 60208, USA
- Department of Ophthalmology, Northwestern University, 645 North Michigan Ave., Chicago IL 60611, USA
- Corresponding author: H.F. Zhang:
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27
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Tang H, Tang Z, Wu Y, Cai Q, Wu L, Chi Y. Differential photoacoustic microscopy technique. OPTICS LETTERS 2013; 38:1503-1505. [PMID: 23632532 DOI: 10.1364/ol.38.001503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Photoacoustic microscopy (PAM), whose image quality largely depends on the optical absorption of samples, provides endogenous information for structural and functional imaging. However, PAM technology in general can not provide edge enhancement imaging for absorbing objects. Therefore, PAM and differential microscopy are integrated for the first time in a single technique to obtain an edge enhancement image. The resolution test target RTA-07 and red blood cells are used as samples to achieve the desired spatial differential photoacoustic imaging. The feasible biomedical application of edge enhancement from the improved differential PAM was demonstrated.
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Affiliation(s)
- Hongchun Tang
- School of Physics and Telecom Engineering, South China Normal University, Guangzhou 510006, China
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Liao LD, Tsytsarev V, Delgado-Martínez I, Li ML, Erzurumlu R, Vipin A, Orellana J, Lin YR, Lai HY, Chen YY, Thakor NV. Neurovascular coupling: in vivo optical techniques for functional brain imaging. Biomed Eng Online 2013; 12:38. [PMID: 23631798 PMCID: PMC3655834 DOI: 10.1186/1475-925x-12-38] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 03/25/2013] [Indexed: 01/21/2023] Open
Abstract
Optical imaging techniques reflect different biochemical processes in the brain, which is closely related with neural activity. Scientists and clinicians employ a variety of optical imaging technologies to visualize and study the relationship between neurons, glial cells and blood vessels. In this paper, we present an overview of the current optical approaches used for the in vivo imaging of neurovascular coupling events in small animal models. These techniques include 2-photon microscopy, laser speckle contrast imaging (LSCI), voltage-sensitive dye imaging (VSDi), functional photoacoustic microscopy (fPAM), functional near-infrared spectroscopy imaging (fNIRS) and multimodal imaging techniques. The basic principles of each technique are described in detail, followed by examples of current applications from cutting-edge studies of cerebral neurovascular coupling functions and metabolic. Moreover, we provide a glimpse of the possible ways in which these techniques might be translated to human studies for clinical investigations of pathophysiology and disease. In vivo optical imaging techniques continue to expand and evolve, allowing us to discover fundamental basis of neurovascular coupling roles in cerebral physiology and pathophysiology.
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Affiliation(s)
- Lun-De Liao
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
| | - Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn street, HSF-2, Baltimore, MD 21201, USA
| | - Ignacio Delgado-Martínez
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
| | - Meng-Lin Li
- Department of Electrical Engineering, National Tsing Hua University, No. 101, Sec. 2, Kuang-Fu Rd, Hsinchu 300, R.O.C, Taiwan
| | - Reha Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn street, HSF-2, Baltimore, MD 21201, USA
| | - Ashwati Vipin
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
| | - Josue Orellana
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
| | - Yan-Ren Lin
- Department of Emergency Medicine, Changhua Christian Hospital, 135 Nanshsiao Street, Changhua 500, R.O.C, Taiwan
| | - Hsin-Yi Lai
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan 333, R.O.C, Taiwan
| | - You-Yin Chen
- Department of Biomedical Engineering, National Yang Ming University, No.155, Sec.2, Linong St, Taipei 112, R.O.C, Taiwan
| | - Nitish V Thakor
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
- Department of Biomedical Engineering, Johns Hopkins University, Traylor 701/720 Rutland Ave, Baltimore, MD 21205, USA
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Tsytsarev V, Arakawa H, Borisov S, Pumbo E, Erzurumlu RS, Papkovsky DB. In vivo imaging of brain metabolism activity using a phosphorescent oxygen-sensitive probe. J Neurosci Methods 2013; 216:146-51. [PMID: 23624034 DOI: 10.1016/j.jneumeth.2013.04.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Revised: 04/09/2013] [Accepted: 04/11/2013] [Indexed: 12/12/2022]
Abstract
Several approaches have been adopted for real-time imaging of neural activity in vivo. We tested a new cell-penetrating phosphorescent oxygen-sensitive probe, NanO2-IR, to monitor temporal and spatial dynamics of oxygen metabolism in the neocortex following peripheral sensory stimulation. Probe solution was applied to the surface of anesthetized mouse brain; optical imaging was performed using a MiCAM-02 system. Trains of whisker stimuli were delivered and associated changes in phosphorescent signal were recorded in the contralateral somatosensory ("barrel") cortex. Sensory stimulation led to changes in oxygenation of activated areas of the barrel cortex. The oxygen imaging results were compared to those produced by the voltage-sensitive dye RH-1691. While the signals emitted by the two probes differed in shape and amplitude, they both faithfully indicated specific whisker evoked cortical activity. Thus, NanO2-IR probe can be used as a tool in visualization and real-time analysis of sensory-evoked neural activity in vivo.
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Affiliation(s)
- Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, HSF II, 20 Penn Street, Baltimore, MD 21201-1075, USA.
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Tsytsarev V, Rao B, Maslov KI, Li L, Wang LV. Photoacoustic and optical coherence tomography of epilepsy with high temporal and spatial resolution and dual optical contrasts. J Neurosci Methods 2013; 216:142-5. [PMID: 23603664 DOI: 10.1016/j.jneumeth.2013.04.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 04/01/2013] [Accepted: 04/04/2013] [Indexed: 01/26/2023]
Abstract
Epilepsy mapping with high spatial and temporal resolution has great significance for both fundamental research on epileptic neurons and the clinical management of epilepsy. In this communication, we demonstrate for the first time in vivo epilepsy mapping with high spatial and temporal resolution and dual optical contrasts in an animal model. Through the variations of a depthresolved optical coherence tomography signal with optical scattering contrast, we observed that epileptic neuron activities modulated the optical refractive index of epileptic neurons and their surrounding tissue. Simultaneously, through neurovasculature coupling mechanisms and optical absorption contrast, we used photoacoustic signals to document the hemodynamic changes of the microvasculature surrounding the epileptic neurons. The epilepsy mapping results were confirmed by a simultaneously recorded electroencephalogram signal during epileptic seizure. Our new epilepsy mapping tool, with high temporal and spatial resolution and dual optical contrasts, may find many applications, such as drug development and epilepsy surgery.
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Affiliation(s)
- Vassiliy Tsytsarev
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
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Tsytsarev V, Bernardelli C, Maslov KI. Living Brain Optical Imaging: Technology, Methods and Applications. ACTA ACUST UNITED AC 2012; 1:180-192. [PMID: 28251038 DOI: 10.1166/jnsne.2012.1020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Within the last few decades, optical imaging methods have yielded revolutionary results when applied to all parts of the central nervous system. The purpose of this review is to analyze research possibilities and limitations of several novel imaging techniques and show some of the most interesting achievements obtained by these methods. Here we covered intrinsic optical imaging, voltage-sensitive dye, photoacoustic, optical coherence tomography, near-infrared spectroscopy and some other techniques. All of them are mainly applicable for experimental neuroscience but some of them also suitable for the clinical studies.
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Affiliation(s)
- Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, HSF II Room S251, 20 Penn Street, Baltimore, MD 21201-1075, USA
| | - Chad Bernardelli
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, HSF II Room S251, 20 Penn Street, Baltimore, MD 21201-1075, USA
| | - Konstantin I Maslov
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, USA
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Lenkov DN, Volnova AB, Pope ARD, Tsytsarev V. Advantages and limitations of brain imaging methods in the research of absence epilepsy in humans and animal models. J Neurosci Methods 2012; 212:195-202. [PMID: 23137652 DOI: 10.1016/j.jneumeth.2012.10.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 10/24/2012] [Accepted: 10/25/2012] [Indexed: 12/18/2022]
Abstract
The purpose of this review is to analyze research possibilities and limitations of several methods, technical tools and their combinations for elucidation of absence epilepsy mechanisms, particularly the childhood absences. Despite the notable collection of simultaneous recording of clinical electroencephalography (EEG) and behavioral changes in relation to absence seizures, shortcomings of scalp EEG in both spatial resolution and precise detection of subcortical centers have limited the understanding of the fundamental mechanisms of altered brain function during and after recurrent epileptic paroxysms. Therefore, in the past decade, EEG recordings have often been combined with simultaneous imaging methods in epilepsy studies. Among imaging methods, the following ones are used regularly: functional magnetic resonance imaging (fMRI), positron-emission tomography (PET), low-resolution electromagnetic tomography (LORETA), single photon emission spectroscopy (SPECT), near-infrared spectroscopy (NIRS), and optical imaging of intrinsic signals (IOS). In addition, voltage-sensitive dye optical imaging method and even photoacoustic microscopy can be applied to animal models of epilepsy. Samplings of some of the most relevant data obtained by the above methods are presented. It appears that the elaboration of more adequate animal models of the patterns of absence seizures during the early postnatal period is necessary for better correspondence of human and animal absence phenomena.
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Affiliation(s)
- Dmitry N Lenkov
- Nevsky Center of Scientific Collaboration-Saint Petersburg, Razjezshaya 43/1 Liter A, Suite 8N, Saint Petersburg 192119, Russia
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Deng Z, Wang Z, Yang X, Luo Q, Gong H. In vivo imaging of hemodynamics and oxygen metabolism in acute focal cerebral ischemic rats with laser speckle imaging and functional photoacoustic microscopy. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:081415-1. [PMID: 23224176 DOI: 10.1117/1.jbo.17.8.081415] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Stroke is a devastating disease. The changes in cerebral hemodynamics and oxygen metabolism associated with stroke play an important role in pathophysiology study. But the changes were difficult to describe with a single imaging modality. Here the changes in cerebral blood flow (CBF), cerebral blood volume (CBV), and oxygen saturation (SO2) were yielded with laser speckle imaging (LSI) and photoacoustic microscopy (PAM) during and after 3-h acute focal ischemic rats. These hemodynamic measures were further synthesized to deduce the changes in oxygen extraction fraction (OEF). The results indicate that all the hemodynamics except CBV had rapid declines within 40-min occlusion of middle cerebral artery (MCAO). CBV in arteries and veins first increased to the maximum value of 112.42 ± 36.69% and 130.58 ± 31.01% by 15 min MCAO; then all the hemodynamics had a persistent reduction with small fluctuations during the ischemic. When ischemia lasted for 3 h, CBF in arteries, veins decreased to 17 ± 14.65%, 24.52 ± 20.66%, respectively, CBV dropped to 62 ± 18.56% and 59 ± 18.48%. And the absolute SO2 decreased by 40.52 ± 22.42% and 54.24 ± 11.77%. After 180-min MCAO, the changes in hemodynamics and oxygen metabolism were also quantified. The study suggested that combining LSI and PAM provides an attractive approach for stroke detection in small animal studies.
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Affiliation(s)
- Zilin Deng
- Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Britton Chance Center for Biomedical Photonics, 1037 Luoyu Road, Wuhan 430074, China
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Shao P, Shi W, Chee RKW, Zemp RJ. Mosaic acquisition and processing for optical-resolution photoacoustic microscopy. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:080503-1. [PMID: 23224154 DOI: 10.1117/1.jbo.17.8.080503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In optical-resolution photo-acoustic microscopy (OR-PAM), data acquisition time is limited by both laser pulse repetition rate (PRR) and scanning speed. Optical-scanning offers high speed, but limited, field of view determined by ultrasound transducer sensitivity. In this paper, we propose a hybrid optical and mechanical-scanning OR-PAM system with mosaic data acquisition and processing. The system employs fast-scanning mirrors and a diode-pumped, nanosecond-pulsed, Ytterbium-doped, 532-nm fiber laser with PRR up to 600 kHz. Data from a sequence of image mosaic patches is acquired systematically, at predetermined mechanical scanning locations, with optical scanning. After all imaging locations are covered, a large panoramic scene is generated by stitching the mosaic patches together. Our proposed system is proven to be at least 20 times faster than previous reported OR-PAM systems.
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Affiliation(s)
- Peng Shao
- University of Alberta, Department of Electrical & Computer Engineering, Edmonton T6G2V4, Canada
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Shao P, Shi W, Hajireza P, Zemp RJ. Integrated micro-endoscopy system for simultaneous fluorescence and optical-resolution photoacoustic imaging. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:076024. [PMID: 22894507 DOI: 10.1117/1.jbo.17.7.076024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We present a new integrated micro-endoscopy system combining label-free, fiber-based, real-time C-scan optical-resolution photoacoustic microscopy (F-OR-PAM) and a high-resolution fluorescence micro-endoscopy system for visualizing fluorescently labeled cellular components and optically absorbing microvasculature simultaneously. With a diode-pumped 532-nm fiber laser, the F-OR-PAM sub-system is able to reach a resolution of ∼7 μm. The fluorescence subsystem, which does not require any mechanical scanning, consists of a 447.5-nm-centered diode laser as the light source, an objective lens, and a CCD camera. Proflavine is used as the fluorescent contrast agent by topical application. The scanning laser and the diode laser light source share the same light path within an optical fiber bundle containing 30,000 individual single-mode fibers. The absorption of proflavine at 532 nm is low, which mitigates absorption bleaching of the contrast agent by the photoacoustic excitation source. We demonstrate imaging in live murine models. The system is able to provide cellular morphology with cellular resolution co-registered with the structural information given by F-OR-PAM. Therefore, the system has the potential to serve as a virtual biopsy technique, helping visualize angiogenesis and the effects of anti-cancer drugs on both cells and the microcirculation, as well as aid in the study of other diseases.
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Affiliation(s)
- Peng Shao
- University of Alberta, Department of Electrical and Computer Engineering, Edmonton, Alberta, T6G 2V4, Canada
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Devor A, Sakadžić S, Srinivasan VJ, Yaseen MA, Nizar K, Saisan PA, Tian P, Dale AM, Vinogradov SA, Franceschini MA, Boas DA. Frontiers in optical imaging of cerebral blood flow and metabolism. J Cereb Blood Flow Metab 2012; 32:1259-76. [PMID: 22252238 PMCID: PMC3390808 DOI: 10.1038/jcbfm.2011.195] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In vivo optical imaging of cerebral blood flow (CBF) and metabolism did not exist 50 years ago. While point optical fluorescence and absorption measurements of cellular metabolism and hemoglobin concentrations had already been introduced by then, point blood flow measurements appeared only 40 years ago. The advent of digital cameras has significantly advanced two-dimensional optical imaging of neuronal, metabolic, vascular, and hemodynamic signals. More recently, advanced laser sources have enabled a variety of novel three-dimensional high-spatial-resolution imaging approaches. Combined, as we discuss here, these methods are permitting a multifaceted investigation of the local regulation of CBF and metabolism with unprecedented spatial and temporal resolution. Through multimodal combination of these optical techniques with genetic methods of encoding optical reporter and actuator proteins, the future is bright for solving the mysteries of neurometabolic and neurovascular coupling and translating them to clinical utility.
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Affiliation(s)
- Anna Devor
- Department of Neurosciences, UCSD, La Jolla, CA, USA.
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Deng Z, Yang X, Gong H, Luo Q. Adaptive synthetic-aperture focusing technique for microvasculature imaging using photoacoustic microscopy. OPTICS EXPRESS 2012; 20:7555-63. [PMID: 22453434 DOI: 10.1364/oe.20.007555] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
To improve the lateral resolution of the blood vessels along arbitrary direction out of focus in photoacoustic microscopy (PAM), we propose an adaptive synthetic-aperture focusing technique (ASAFT) for microvasculature imaging which can be automatically applied to each branch of blood vessels, based on our previous two-dimensional (2D) SAFT. The ASAFT is validated both in the phantom study and in vivo imaging. The results demonstrate that ASAFT can provide images of blood vessels with better lateral resolution both at different depths and along various directions compared with one-dimensional and 2D SAFT.
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Affiliation(s)
- Zilin Deng
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong, University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
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Tsytsarev V, Maslov KI, Yao J, Parameswar AR, Demchenko AV, Wang LV. In vivo imaging of epileptic activity using 2-NBDG, a fluorescent deoxyglucose analog. J Neurosci Methods 2011; 203:136-40. [PMID: 21939688 DOI: 10.1016/j.jneumeth.2011.09.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 09/06/2011] [Accepted: 09/07/2011] [Indexed: 11/15/2022]
Abstract
Accurately locating epileptic foci has great importance in advancing the treatment of epilepsy. In this study, epileptic seizures were first induced by intracortical injection of 4-aminopyridine in rats. A fluorescent deoxyglucose substitute, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), was then continuously injected via the tail vein. Brain glucose metabolism was subsequently monitored by fluorescence imaging of 2-NBDG. The initial uptake rate of 2-NBDG at the injection site of 4-aminopyridine significantly exceeded that of the control injection site, which indicated local hypermetabolism induced by seizures. Our results show that 2-NBDG can be used for localizing epileptic foci.
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Affiliation(s)
- Vassiliy Tsytsarev
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA.
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