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Buehler A, Brown E, Paulus L, Eckstein M, Thoma O, Oraiopoulou M, Rother U, Hoerning A, Hartmann A, Neurath MF, Woelfle J, Friedrich O, Waldner MJ, Knieling F, Bohndiek SE, Regensburger AP. Transrectal Absorber Guide Raster-Scanning Optoacoustic Mesoscopy for Label-Free In Vivo Assessment of Colitis. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300564. [PMID: 37083262 PMCID: PMC10288266 DOI: 10.1002/advs.202300564] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/21/2023] [Indexed: 05/03/2023]
Abstract
Optoacoustic imaging (OAI) enables microscale imaging of endogenous chromophores such as hemoglobin at significantly higher penetration depths compared to other optical imaging technologies. Raster-scanning optoacoustic mesoscopy (RSOM) has recently been shown to identify superficial microvascular changes associated with human skin pathologies. In animal models, the imaging depth afforded by RSOM can enable entirely new capabilities for noninvasive imaging of vascular structures in the gastrointestinal tract, but exact localization of intra-abdominal organs is still elusive. Herein the development and application of a novel transrectal absorber guide for RSOM (TAG-RSOM) is presented to enable accurate transabdominal localization and assessment of colonic vascular networks in vivo. The potential of TAG-RSOM is demonstrated through application during mild and severe acute colitis in mice. TAG-RSOM enables visualization of transmural vascular networks, with changes in colon wall thickness, blood volume, and OAI signal intensities corresponding to colitis-associated inflammatory changes. These findings suggest TAG-RSOM can provide a novel monitoring tool in preclinical IBD models, refining animal procedures and underlines the capabilities of such technologies to address inflammatory bowel diseases in humans.
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Affiliation(s)
- Adrian Buehler
- Department of Pediatrics and Adolescent MedicineUniversity Hospital ErlangenFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91054ErlangenGermany
| | - Emma Brown
- Department of Physics and Cancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeCB2 0REUK
| | - Lars‐Philip Paulus
- Department of Pediatrics and Adolescent MedicineUniversity Hospital ErlangenFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91054ErlangenGermany
| | - Markus Eckstein
- Institute of PathologyFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91054ErlangenGermany
| | - Oana‐Maria Thoma
- Department of Medicine 1University Hospital ErlangenFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91052ErlangenGermany
| | - Mariam‐Eleni Oraiopoulou
- Department of Physics and Cancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeCB2 0REUK
| | - Ulrich Rother
- Department of Vascular SurgeryUniversity Hospital ErlangenFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91054ErlangenGermany
| | - André Hoerning
- Department of Pediatrics and Adolescent MedicineUniversity Hospital ErlangenFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91054ErlangenGermany
| | - Arndt Hartmann
- Institute of PathologyFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91054ErlangenGermany
| | - Markus F. Neurath
- Department of Medicine 1University Hospital ErlangenFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91052ErlangenGermany
| | - Joachim Woelfle
- Department of Pediatrics and Adolescent MedicineUniversity Hospital ErlangenFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91054ErlangenGermany
| | - Oliver Friedrich
- Institute of Medical BiotechnologyDepartment of Chemical and Biological EngineeringFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91052ErlangenGermany
| | - Maximilian J. Waldner
- Department of Medicine 1University Hospital ErlangenFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91052ErlangenGermany
| | - Ferdinand Knieling
- Department of Pediatrics and Adolescent MedicineUniversity Hospital ErlangenFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91054ErlangenGermany
| | - Sarah E. Bohndiek
- Department of Physics and Cancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeCB2 0REUK
| | - Adrian P. Regensburger
- Department of Pediatrics and Adolescent MedicineUniversity Hospital ErlangenFriedrich‐Alexander‐Universität (FAU) Erlangen‐Nürnberg91054ErlangenGermany
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2
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Pang W, Wang Y, Guo L, Wang B, Lai P, Xiao J. Two-Dimensional Photoacoustic/Ultrasonic Endoscopic Imaging Based on a Line-Focused Transducer. Front Bioeng Biotechnol 2022; 9:807633. [PMID: 35071214 PMCID: PMC8770734 DOI: 10.3389/fbioe.2021.807633] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/16/2021] [Indexed: 11/13/2022] Open
Abstract
Existing acoustic-resolution photoacoustic/ultrasonic endoscopy (PA/USE) generally employs a point-focused transducer for ultrasound detection, which is only sensitive in its focal region, thus the lateral resolution and sensitivity drop dramatically when the targets move far from its focus. Even if a dynamic focusing algorithm is applied, the sensitivity out of the transducer focus is still much lower than that in the focus in ultrasonic imaging mode. In this work, we propose an acoustic-resolution PA/USE with a line-focused transducer to realize automatic focusing for the first time. In comparison to a point-focused transducer, the line-focused transducer emits a more uniform sound field, causing the original signal intensity and signal-to-noise ratio (SNR) of the front and rear targets to be closer in the radial direction, which is beneficial for improving target signal uniformity in ultrasonic imaging. Simultaneously, we improved the resolution of the defocus area by modifying a prior work of back-projection (BP) reconstruction algorithm typically used in point-focused transducer based PAE and applying it to line-focused PA/USE. This combined approach may significantly enhance the depth of field of ultrasonic imaging and the resolution of the defocus zone in PA/US imaging, compared to the conventional method. Sufficient numerical simulations and phantom experiments were performed to verify this method. The results show that our method can effectively improve the lateral resolution in the image's defocused region to achieve automatic focusing and perfectly solve the defect of the target signal difference in the far-focus region in ultrasonic imaging, while also enhancing the image SNR and contrast. The proposed method in this paper lays foundations for the realization of photoacoustic/ultrasonic combined endoscopy with enhanced lateral resolution and depth of field, which can potentially benefit a many of biomedical applications.
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Affiliation(s)
- Weiran Pang
- Department of Biomedical Engineering, School of Basic Medical Science, Central South University, Changsha, China.,Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, Hong Kong SAR, China
| | - Yongjun Wang
- Department of Biomedical Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Lili Guo
- Department of Biomedical Engineering, College of Biology, Hunan University, Changsha, China
| | - Bo Wang
- Department of Biomedical Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Puxiang Lai
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, Hong Kong SAR, China
| | - Jiaying Xiao
- Department of Biomedical Engineering, School of Basic Medical Science, Central South University, Changsha, China
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3
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Palma-Chavez J, Pfefer TJ, Agrawal A, Jokerst JV, Vogt WC. Review of consensus test methods in medical imaging and current practices in photoacoustic image quality assessment. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210176VSSR. [PMID: 34510850 PMCID: PMC8434148 DOI: 10.1117/1.jbo.26.9.090901] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 08/17/2021] [Indexed: 05/06/2023]
Abstract
SIGNIFICANCE Photoacoustic imaging (PAI) is a powerful emerging technology with broad clinical applications, but consensus test methods are needed to standardize performance evaluation and accelerate translation. AIM To review consensus image quality test methods for mature imaging modalities [ultrasound, magnetic resonance imaging (MRI), x-ray CT, and x-ray mammography], identify best practices in phantom design and testing procedures, and compare against current practices in PAI phantom testing. APPROACH We reviewed scientific papers, international standards, clinical accreditation guidelines, and professional society recommendations describing medical image quality test methods. Observations are organized by image quality characteristics (IQCs), including spatial resolution, geometric accuracy, imaging depth, uniformity, sensitivity, low-contrast detectability, and artifacts. RESULTS Consensus documents typically prescribed phantom geometry and material property requirements, as well as specific data acquisition and analysis protocols to optimize test consistency and reproducibility. While these documents considered a wide array of IQCs, reported PAI phantom testing focused heavily on in-plane resolution, depth of visualization, and sensitivity. Understudied IQCs that merit further consideration include out-of-plane resolution, geometric accuracy, uniformity, low-contrast detectability, and co-registration accuracy. CONCLUSIONS Available medical image quality standards provide a blueprint for establishing consensus best practices for photoacoustic image quality assessment and thus hastening PAI technology advancement, translation, and clinical adoption.
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Affiliation(s)
- Jorge Palma-Chavez
- University of California San Diego, Department of NanoEngineering, La Jolla, California, United States
| | - T. Joshua Pfefer
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, United States
| | - Anant Agrawal
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, United States
| | - Jesse V. Jokerst
- University of California San Diego, Department of NanoEngineering, La Jolla, California, United States
- University of California San Diego, Department of Radiology, La Jolla, California, United States
- University of California San Diego, Materials Science and Engineering Program, La Jolla, California, United States
| | - William C. Vogt
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, United States
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4
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Tian C, Zhang C, Zhang H, Xie D, Jin Y. Spatial resolution in photoacoustic computed tomography. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2021; 84:036701. [PMID: 33434890 DOI: 10.1088/1361-6633/abdab9] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 01/12/2021] [Indexed: 06/12/2023]
Abstract
Photoacoustic computed tomography (PACT) is a novel biomedical imaging modality and has experienced fast developments in the past two decades. Spatial resolution is an important criterion to measure the imaging performance of a PACT system. Here we survey state-of-the-art literature on the spatial resolution of PACT and analyze resolution degradation models from signal generation, propagation, reception, to image reconstruction. Particularly, the impacts of laser pulse duration, acoustic attenuation, acoustic heterogeneity, detector bandwidth, detector aperture, detector view angle, signal sampling, and image reconstruction algorithms are reviewed and discussed. Analytical expressions of point spread functions related to these impacting factors are summarized based on rigorous mathematical formulas. State-of-the-art approaches devoted to enhancing spatial resolution are also reviewed. This work is expected to elucidate the concept of spatial resolution in PACT and inspire novel image quality enhancement techniques.
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Affiliation(s)
- Chao Tian
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Chenxi Zhang
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Haoran Zhang
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Dan Xie
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Yi Jin
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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5
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Ali Z, Zakian C, Ntziachristos V. Ultra-broadband axicon transducer for optoacoustic endoscopy. Sci Rep 2021; 11:1654. [PMID: 33462279 PMCID: PMC7814136 DOI: 10.1038/s41598-021-81117-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/29/2020] [Indexed: 01/12/2023] Open
Abstract
Image performance in optoacoustic endoscopy depends markedly on the design of the transducer employed. Ideally, high-resolution performance is required over an expanded depth of focus. Current optoacoustic focused transducers achieve lateral resolutions in the range of tens of microns in the mesoscopic regime, but their depth of focus is limited to hundreds of microns by the nature of their spherical geometry. We designed an ultra-broadband axicon detector with a 2 mm central aperture and investigated whether the imaging characteristics exceeded those of a spherical detector of similar size. We show a previously undocumented ability to achieve a broadband elongated pencil-beam optoacoustic sensitivity with an axicon detection geometry, providing approximately 40 μm-lateral resolution maintained over a depth of focus of 950 μm—3.8 times that of the reference spherical detector. This performance could potentially lead to optoacoustic endoscopes that can visualize optical absorption deeper and with higher resolution than any other optical endoscope today.
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Affiliation(s)
- Zakiullah Ali
- Chair of Biological Imaging, Central Institute for Translational Cancer Research (TranslaTUM), Technical University of Munich, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany
| | - Christian Zakian
- Chair of Biological Imaging, Central Institute for Translational Cancer Research (TranslaTUM), Technical University of Munich, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany
| | - Vasilis Ntziachristos
- Chair of Biological Imaging, Central Institute for Translational Cancer Research (TranslaTUM), Technical University of Munich, Munich, Germany. .,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany.
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6
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He Z, Wang P, Ye X. Novel endoscopic optical diagnostic technologies in medical trial research: recent advancements and future prospects. Biomed Eng Online 2021; 20:5. [PMID: 33407477 PMCID: PMC7789310 DOI: 10.1186/s12938-020-00845-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 12/23/2020] [Indexed: 12/20/2022] Open
Abstract
Novel endoscopic biophotonic diagnostic technologies have the potential to non-invasively detect the interior of a hollow organ or cavity of the human body with subcellular resolution or to obtain biochemical information about tissue in real time. With the capability to visualize or analyze the diagnostic target in vivo, these techniques gradually developed as potential candidates to challenge histopathology which remains the gold standard for diagnosis. Consequently, many innovative endoscopic diagnostic techniques have succeeded in detection, characterization, and confirmation: the three critical steps for routine endoscopic diagnosis. In this review, we mainly summarize researches on emerging endoscopic optical diagnostic techniques, with emphasis on recent advances. We also introduce the fundamental principles and the development of those techniques and compare their characteristics. Especially, we shed light on the merit of novel endoscopic imaging technologies in medical research. For example, hyperspectral imaging and Raman spectroscopy provide direct molecular information, while optical coherence tomography and multi-photo endomicroscopy offer a more extensive detection range and excellent spatial-temporal resolution. Furthermore, we summarize the unexplored application fields of these endoscopic optical techniques in major hospital departments for biomedical researchers. Finally, we provide a brief overview of the future perspectives, as well as bottlenecks of those endoscopic optical diagnostic technologies. We believe all these efforts will enrich the diagnostic toolbox for endoscopists, enhance diagnostic efficiency, and reduce the rate of missed diagnosis and misdiagnosis.
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Affiliation(s)
- Zhongyu He
- Biosensor National Special Laboratory, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310027, People's Republic of China
| | - Peng Wang
- Biosensor National Special Laboratory, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310027, People's Republic of China
| | - Xuesong Ye
- Biosensor National Special Laboratory, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310027, People's Republic of China.
- State Key Laboratory of CAD and CG, Zhejiang University, Hangzhou, 310058, People's Republic of China.
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7
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Das D, Sharma A, Rajendran P, Pramanik M. Another decade of photoacoustic imaging. Phys Med Biol 2020; 66. [PMID: 33361580 DOI: 10.1088/1361-6560/abd669] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/23/2020] [Indexed: 01/09/2023]
Abstract
Photoacoustic imaging - a hybrid biomedical imaging modality finding its way to clinical practices. Although the photoacoustic phenomenon was known more than a century back, only in the last two decades it has been widely researched and used for biomedical imaging applications. In this review we focus on the development and progress of the technology in the last decade (2010-2020). From becoming more and more user friendly, cheaper in cost, portable in size, photoacoustic imaging promises a wide range of applications, if translated to clinic. The growth of photoacoustic community is steady, and with several new directions researchers are exploring, it is inevitable that photoacoustic imaging will one day establish itself as a regular imaging system in the clinical practices.
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Affiliation(s)
- Dhiman Das
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, SINGAPORE
| | - Arunima Sharma
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, SINGAPORE
| | - Praveenbalaji Rajendran
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, SINGAPORE
| | - Manojit Pramanik
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, N1.3-B2-11, Singapore, 637457, SINGAPORE
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8
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Ansari R, Zhang EZ, Desjardins AE, Beard PC. Miniature all-optical flexible forward-viewing photoacoustic endoscopy probe for surgical guidance. OPTICS LETTERS 2020; 45:6238-6241. [PMID: 33186959 PMCID: PMC8219374 DOI: 10.1364/ol.400295] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 05/13/2023]
Abstract
A miniature flexible photoacoustic endoscopy probe that provides high-resolution 3D images of vascular structures in the forward-viewing configuration is described. A planar Fabry-Perot ultrasound sensor with a -3dB bandwidth of 53 MHz located at the tip of the probe is interrogated via a flexible fiber bundle and a miniature optical relay system to realize an all-optical probe measuring 7.4 mm in outer diameter at the tip. This approach to photoacoustic endoscopy offers advantages over previous piezoelectric based distal-end scanning probes. These include a forward-viewing configuration in widefield photoacoustic tomography mode, finer spatial sampling (87 µm spatial sampling interval), and wider detection bandwidth (53 MHz) than has been achievable with conventional ultrasound detection technology and an all-optical passive imaging head for safe endoscopic use.
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Affiliation(s)
- Rehman Ansari
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, WC1E 6BT, UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, 43-45 Foley Street, London W1W 7TS, UK
| | - Edward Z. Zhang
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, WC1E 6BT, UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, 43-45 Foley Street, London W1W 7TS, UK
| | - Adrien E. Desjardins
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, WC1E 6BT, UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, 43-45 Foley Street, London W1W 7TS, UK
| | - Paul C. Beard
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, WC1E 6BT, UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, 43-45 Foley Street, London W1W 7TS, UK
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9
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Li Y, Chen J, Chen Z. Multimodal intravascular imaging technology for characterization of atherosclerosis. JOURNAL OF INNOVATIVE OPTICAL HEALTH SCIENCES 2020; 13:2030001. [PMID: 32308744 PMCID: PMC7164814 DOI: 10.1142/s1793545820300013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Early detection of vulnerable plaques is the critical step in the prevention of acute coronary events. Morphology, composition, and mechanical property of a coronary artery have been demonstrated to be the key characteristics for the identification of vulnerable plaques. Several intravascular multimodal imaging technologies providing co-registered simultaneous images have been developed and applied in clinical studies to improve the characterization of atherosclerosis. In this paper, the authors review the present system and probe designs of representative intravascular multimodal techniques. In addition, the scientific innovations, potential limitations, and future directions of these technologies are also discussed.
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Affiliation(s)
- Yan Li
- Beckman Laser Institute, University of California, Irvine 1002 Health Sciences Road, Irvine, CA 92617 USA
| | - Jason Chen
- Beckman Laser Institute, University of California, Irvine 1002 Health Sciences Road, Irvine, CA 92617 USA
| | - Zhongping Chen
- Department of Biomedical Engineering University of California, Irvine, CA 92697-2700 USA
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10
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Zhao T, Desjardins AE, Ourselin S, Vercauteren T, Xia W. Minimally invasive photoacoustic imaging: Current status and future perspectives. PHOTOACOUSTICS 2019; 16:100146. [PMID: 31871889 PMCID: PMC6909166 DOI: 10.1016/j.pacs.2019.100146] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/26/2019] [Accepted: 09/30/2019] [Indexed: 05/09/2023]
Abstract
Photoacoustic imaging (PAI) is an emerging biomedical imaging modality that is based on optical absorption contrast, capable of revealing distinct spectroscopic signatures of tissue at high spatial resolution and large imaging depths. However, clinical applications of conventional non-invasive PAI systems have been restricted to examinations of tissues at depths less than a few cm due to strong light attenuation. Minimally invasive photoacoustic imaging (miPAI) has greatly extended the landscape of PAI by delivering excitation light within tissue through miniature fibre-optic probes. In the past decade, various miPAI systems have been developed with demonstrated applicability in several clinical fields. In this article, we present an overview of the current status of miPAI and our thoughts on future perspectives.
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Affiliation(s)
- Tianrui Zhao
- School of Biomedical Engineering and Imaging Sciences, King’s College London, 4th Floor, Lambeth Wing St Thomas’ Hospital London, London SE1 7EH, United Kingdom
| | - Adrien E. Desjardins
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Charles Bell House, 67-73 Riding House Street, London W1W 7EJ, United Kingdom
| | - Sebastien Ourselin
- School of Biomedical Engineering and Imaging Sciences, King’s College London, 4th Floor, Lambeth Wing St Thomas’ Hospital London, London SE1 7EH, United Kingdom
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Tom Vercauteren
- School of Biomedical Engineering and Imaging Sciences, King’s College London, 4th Floor, Lambeth Wing St Thomas’ Hospital London, London SE1 7EH, United Kingdom
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Wenfeng Xia
- School of Biomedical Engineering and Imaging Sciences, King’s College London, 4th Floor, Lambeth Wing St Thomas’ Hospital London, London SE1 7EH, United Kingdom
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
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11
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He H, Stylogiannis A, Afshari P, Wiedemann T, Steiger K, Buehler A, Zakian C, Ntziachristos V. Capsule optoacoustic endoscopy for esophageal imaging. JOURNAL OF BIOPHOTONICS 2019; 12:e201800439. [PMID: 31034135 PMCID: PMC7065619 DOI: 10.1002/jbio.201800439] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 04/25/2019] [Accepted: 04/26/2019] [Indexed: 05/03/2023]
Abstract
Detection and monitoring of esophageal cancer severity require an imaging technique sensitive enough to detect early pathological changes in the esophagus and capable of analyzing the esophagus over 360 °in a non-invasive manner. Optoacoustic endoscopy (COE) has been shown to resolve superficial vascular structure of the esophageal lumen in rats and rabbits using catheter-type probes. Although these systems can work well in small animals, they are unsuitable for larger lumens with thicker walls as required for human esophageal screening, due to their lack of position stability along the full organ circumference, sub-optimal acoustic coupling and limited signal-to-noise ratio (SNR). In this work, we introduce a novel capsule COE system that provides high-quality 360° images of the entire lumen, specifically designed for typical dimensions of human esophagus. The pill-shaped encapsulated probe consists of a novel and highly sensitive ultrasound transducer fitted with an integrated miniature pre-amplifier, which increases SNR of 10 dB by minimizing artifacts during signal transmission compared to the configuration without the preamplifier. The scanner rotates helically around the central axis of the probe to capture three-dimensional images with uniform quality. We demonstrate for the first time ex vivo volumetric vascular network images to a depth of 2 mm in swine esophageal lining using COE. Vascular information can be resolved within the mucosa and submucosa layers as confirmed by histology of samples stained with hematoxylin and eosin and with antibody against vascular marker CD31. COE creates new opportunities for optoacoustic screening of esophageal cancer in humans.
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Affiliation(s)
- Hailong He
- Institute of Biological and Medical ImagingHelmholtz Zentrum MünchenNeuherbergGermany
- Chair of Biological Imaging and TranslaTUMTechnische Universität MünchenMunichGermany
| | - Antonios Stylogiannis
- Institute of Biological and Medical ImagingHelmholtz Zentrum MünchenNeuherbergGermany
- Chair of Biological Imaging and TranslaTUMTechnische Universität MünchenMunichGermany
| | - Parastoo Afshari
- Institute of Biological and Medical ImagingHelmholtz Zentrum MünchenNeuherbergGermany
- Chair of Biological Imaging and TranslaTUMTechnische Universität MünchenMunichGermany
| | - Tobias Wiedemann
- Institute for Diabetes and CancerHelmholtz Zentrum MünchenNeuherbergGermany
| | - Katja Steiger
- Department of PathologyKlinikum Rechts der Isar, Technical University of MunichMunichGermany
| | - Andreas Buehler
- Institute of Biological and Medical ImagingHelmholtz Zentrum MünchenNeuherbergGermany
- Chair of Biological Imaging and TranslaTUMTechnische Universität MünchenMunichGermany
| | - Christian Zakian
- Institute of Biological and Medical ImagingHelmholtz Zentrum MünchenNeuherbergGermany
- Chair of Biological Imaging and TranslaTUMTechnische Universität MünchenMunichGermany
| | - Vasilis Ntziachristos
- Institute of Biological and Medical ImagingHelmholtz Zentrum MünchenNeuherbergGermany
- Chair of Biological Imaging and TranslaTUMTechnische Universität MünchenMunichGermany
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12
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Deán-Ben XL, Razansky D. Optoacoustic image formation approaches-a clinical perspective. Phys Med Biol 2019; 64:18TR01. [PMID: 31342913 DOI: 10.1088/1361-6560/ab3522] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Clinical translation of optoacoustic imaging is fostered by the rapid technical advances in imaging performance as well as the growing number of clinicians recognizing the immense diagnostic potential of this technology. Clinical optoacoustic systems are available in multiple configurations, including hand-held and endoscopic probes as well as raster-scan approaches. The hardware design must be adapted to the accessible portion of the imaged region and other application-specific requirements pertaining the achievable depth, field of view or spatio-temporal resolution. Equally important is the adequate choice of the signal and image processing approach, which is largely responsible for the resulting imaging performance. Thus, new image reconstruction algorithms are constantly evolving in parallel to the newly-developed set-ups. This review focuses on recent progress on optoacoustic image formation algorithms and processing methods in the clinical setting. Major reconstruction challenges include real-time image rendering in two and three dimensions, efficient hybridization with other imaging modalitites as well as accurate interpretation and quantification of bio-markers, herein discussed in the context of ongoing progress in clinical translation.
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Affiliation(s)
- Xosé Luís Deán-Ben
- Faculty of Medicine and Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland. Department of Information Technology and Electrical Engineering and Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland
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13
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Lei H, Johnson LA, Eaton KA, Liu S, Ni J, Wang X, Higgins PDR, Xu G. Characterizing intestinal strictures of Crohn's disease in vivo by endoscopic photoacoustic imaging. BIOMEDICAL OPTICS EXPRESS 2019; 10:2542-2555. [PMID: 31143502 PMCID: PMC6524586 DOI: 10.1364/boe.10.002542] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/25/2019] [Accepted: 03/25/2019] [Indexed: 05/21/2023]
Abstract
Crohn's disease (CD) is one type of inflammatory bowel disease where both inflammation and fibrosis cause the thickening of the bowel wall and development of the strictures. Accurate assessment of the strictures is critical for the management of CD because the fibrotic strictures must be removed surgically. In this study, a prototype capsule-shaped acoustic resolution photoacoustic (PA) endoscope, which can perform mulitwavelength side-view scanning, was developed to characterize the intestinal strictures of CD. The imaging performance of the probe was tested in phantom experiments and a rabbit trinitrobenzene sulfonic acid (TNBS) model with acute (inflammatory only) or chronic (mixed fibrotic and inflammatory) colitis in vivo. The motion artifacts due to intestinal peristalsis and the respiratory motion of the animals were compensated to improve image qualities. Quantitative molecular component images derived from multi-wavelength PA measurements of normal, acute and chronic intestinal strictures demonstrated statistically significant differences among the three groups that were confirmed by histopathology. A longitudinal study demonstrated the capability of the system in monitoring the development of fibrosis. The results suggest that the proposed novel, capsule-shaped acoustic resolution PA endoscope can be used to characterize fibrostenotic disease in vivo.
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Affiliation(s)
- Hao Lei
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Laura A. Johnson
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Kathryn A. Eaton
- Department of Microbiology and Immunology, University of Michigan Medical Center, Ann Arbor, Michigan, MI 48109, USA
| | - Shengchun Liu
- College of Physical Science and Technology, Heilongjiang University, Harbin, 150080, China
| | - Jun Ni
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xueding Wang
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Peter D. R. Higgins
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Guan Xu
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Abstract
Fuelled by innovation, optical microscopy plays a critical role in the life sciences and medicine, from basic discovery to clinical diagnostics. However, optical microscopy is limited by typical penetration depths of a few hundred micrometres for in vivo interrogations in the visible spectrum. Optoacoustic microscopy complements optical microscopy by imaging the absorption of light, but it is similarly limited by penetration depth. In this Review, we summarize progress in the development and applicability of optoacoustic mesoscopy (OPAM); that is, optoacoustic imaging with acoustic resolution and wide-bandwidth ultrasound detection. OPAM extends the capabilities of optical imaging beyond the depths accessible to optical and optoacoustic microscopy, and thus enables new applications. We explain the operational principles of OPAM, its placement as a bridge between optoacoustic microscopy and optoacoustic macroscopy, and its performance in the label-free visualization of tissue pathophysiology, such as inflammation, oxygenation, vascularization and angiogenesis. We also review emerging applications of OPAM in clinical and biological imaging.
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Upputuri PK, Pramanik M. Photoacoustic imaging in the second near-infrared window: a review. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-20. [PMID: 30968648 PMCID: PMC6990072 DOI: 10.1117/1.jbo.24.4.040901] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 03/18/2019] [Indexed: 05/04/2023]
Abstract
Photoacoustic (PA) imaging is an emerging medical imaging modality that combines optical excitation and ultrasound detection. Because ultrasound scatters much less than light in biological tissues, PA generates high-resolution images at centimeters depth. In recent years, wavelengths in the second near-infrared (NIR-II) window (1000 to 1700 nm) have been increasingly explored due to its potential for preclinical and clinical applications. In contrast to the conventional PA imaging in the visible (400 to 700 nm) and the first NIR-I (700 to 1000 nm) window, PA imaging in the NIR-II window offers numerous advantages, including high spatial resolution, deeper penetration depth, reduced optical absorption, and tissue scattering. Moreover, the second window allows a fivefold higher light excitation energy density compared to the visible window for enhancing the imaging depth significantly. We highlight the importance of the second window for PA imaging and discuss the various NIR-II PA imaging systems and contrast agents with strong absorption in the NIR-II spectral region. Numerous applications of NIR-II PA imaging, including whole-body animal imaging and human imaging, are also discussed.
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Affiliation(s)
- Paul Kumar Upputuri
- Nanyang Technological University, School of Chemical and Biomedical Engineering, Singapore
| | - Manojit Pramanik
- Nanyang Technological University, School of Chemical and Biomedical Engineering, Singapore
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Stammes MA, Bugby SL, Porta T, Pierzchalski K, Devling T, Otto C, Dijkstra J, Vahrmeijer AL, de Geus-Oei LF, Mieog JSD. Modalities for image- and molecular-guided cancer surgery. Br J Surg 2018; 105:e69-e83. [PMID: 29341161 DOI: 10.1002/bjs.10789] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 10/25/2017] [Accepted: 11/05/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Surgery is the cornerstone of treatment for many solid tumours. A wide variety of imaging modalities are available before surgery for staging, although surgeons still rely primarily on visual and haptic cues in the operating environment. Image and molecular guidance might improve the adequacy of resection through enhanced tumour definition and detection of aberrant deposits. Intraoperative modalities available for image- and molecular-guided cancer surgery are reviewed here. METHODS Intraoperative cancer detection techniques were identified through a systematic literature search, with selection of peer-reviewed publications from January 2012 to January 2017. Modalities were reviewed, described and compared according to 25 predefined characteristics. To summarize the data in a comparable way, a three-point rating scale was applied to quantitative characteristics. RESULTS The search identified ten image- and molecular-guided surgery techniques, which can be divided into four groups: conventional, optical, nuclear and endogenous reflectance modalities. Conventional techniques are the most well known imaging modalities, but unfortunately have the drawback of a defined resolution and long acquisition time. Optical imaging is a real-time modality; however, the penetration depth is limited. Nuclear modalities have excellent penetration depth, but their intraoperative use is limited by the use of radioactivity. Endogenous reflectance modalities provide high resolution, although with a narrow field of view. CONCLUSION Each modality has its strengths and weaknesses; no single technique will be suitable for all surgical procedures. Strict selection of modalities per cancer type and surgical requirements is required as well as combining techniques to find the optimal balance.
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Affiliation(s)
- M A Stammes
- Department of Radiology, Leiden University Medical Centre, Leiden, The Netherlands.,Percuros, Enschede, The Netherlands
| | - S L Bugby
- Space Research Centre, Department of Physics and Astronomy, University of Leicester, Leicester, UK
| | - T Porta
- Maastricht MultiModal Molecular Imaging Institute (M4I), Division of Imaging Mass Spectrometry, Maastricht University, Maastricht, The Netherlands
| | - K Pierzchalski
- Maastricht MultiModal Molecular Imaging Institute (M4I), Division of Imaging Mass Spectrometry, Maastricht University, Maastricht, The Netherlands
| | | | - C Otto
- Medical Cell Bio Physics, University of Twente, Enschede, The Netherlands
| | - J Dijkstra
- Department of Radiology, Leiden University Medical Centre, Leiden, The Netherlands
| | - A L Vahrmeijer
- Department of Surgery, Leiden University Medical Centre, Leiden, The Netherlands
| | - L-F de Geus-Oei
- Department of Radiology, Leiden University Medical Centre, Leiden, The Netherlands.,Biomedical Photonic Imaging Group, MIRA Institute, University of Twente, Enschede, The Netherlands
| | - J S D Mieog
- Department of Surgery, Leiden University Medical Centre, Leiden, The Netherlands
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17
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Lan B, Liu W, Wang YC, Shi J, Li Y, Xu S, Sheng H, Zhou Q, Zou J, Hoffmann U, Yang W, Yao J. High-speed widefield photoacoustic microscopy of small-animal hemodynamics. BIOMEDICAL OPTICS EXPRESS 2018; 9:4689-4701. [PMID: 30319896 PMCID: PMC6179413 DOI: 10.1364/boe.9.004689] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/03/2018] [Accepted: 09/04/2018] [Indexed: 05/18/2023]
Abstract
Optical-resolution photoacoustic microscopy (OR-PAM) has become a popular tool in small-animal hemodynamic studies. However, previous OR-PAM techniques variously lacked a high imaging speed and/or a large field of view, impeding the study of highly dynamic physiologic and pathophysiologic processes over a large region of interest. Here we report a high-speed OR-PAM system with an ultra-wide field of view, enabled by an innovative water-immersible hexagon-mirror scanner. By driving the hexagon-mirror scanner with a high-precision DC motor, the new OR-PAM has achieved a cross-sectional frame rate of 900 Hz over a 12-mm scanning range, which is 3900 times faster than our previous motor-scanner-based system and 10 times faster than the MEMS-scanner-based system. Using this hexagon-scanner-based OR-PAM system, we have imaged epinephrine-induced vasoconstriction in the whole mouse ear and vascular reperfusion after ischemic stroke in the mouse cortex in vivo, with a high spatial resolution and high volumetric imaging speed. We expect that the hexagon-scanner-based OR-PAM system will become a powerful tool for small animal imaging where the hemodynamic responses over a large field of view are of interest.
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Affiliation(s)
- Bangxin Lan
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Wei Liu
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Ya-chao Wang
- Center for Perioperative Organ Protection (CPOP), Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Junhui Shi
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Yang Li
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Song Xu
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Tx 77843, USA
| | - Huaxin Sheng
- Center for Perioperative Organ Protection (CPOP), Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Qifa Zhou
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Jun Zou
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Tx 77843, USA
| | - Ulrike Hoffmann
- Center for Perioperative Organ Protection (CPOP), Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Wei Yang
- Center for Perioperative Organ Protection (CPOP), Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Junjie Yao
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
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He H, Buehler A, Bozhko D, Jian X, Cui Y, Ntziachristos V. Importance of Ultrawide Bandwidth for Optoacoustic Esophagus Imaging. IEEE TRANSACTIONS ON MEDICAL IMAGING 2018; 37:1162-1167. [PMID: 29727279 DOI: 10.1109/tmi.2017.2777891] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Optoacoustic (photoacoustic) endoscopy has shown potential to reveal complementary contrast to optical endoscopy methods, indicating clinical relevance. However operational parameters for accurate optoacoustic endoscopy must be specified for optimal performance. Recent support from the EU Horizon 2020 program ESOTRAC to develop a next-generation optoacoustic esophageal endoscope directs the interrogation of the optimal frequency required for accurate implementation. We simulated the frequency response of the esophagus wall and then validated the simulation results with experimental measurements of pig esophagus. Phantoms and fresh pig esophagus samples were measured using two detectors with central frequencies of 15 or 50 MHz, and the imaging performance of both detectors was compared. We analyzed the frequency bandwidth of optoacoustic signals in relation to morphological layer structures of the esophagus and found the 50 MHz detector to differentiate layer structures better than the 15 MHz detector. Furthermore, we identify the necessary detection bandwidth for visualizing esophagus morphology and selecting ultrasound transducers for future optoacoustic endoscopy of the esophagus.
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Guo Z, Li Y, Chen SL. Miniature probe for in vivo optical- and acoustic-resolution photoacoustic microscopy. OPTICS LETTERS 2018; 43:1119-1122. [PMID: 29489793 DOI: 10.1364/ol.43.001119] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/31/2018] [Indexed: 05/18/2023]
Abstract
We present a miniature probe capable of both optical-resolution (OR) and acoustic-resolution (AR) photoacoustic microscopy. A gradient-index-lens fiber and a multimode fiber are used to deliver light for OR and AR illumination, respectively. The probe achieves lateral resolution of 3.1 μm for OR mode and 46-249 μm (at depth of 1.2-4.3 mm) for AR mode, respectively. The size of the probe attains 3.7 mm in diameter, which can be used for endoscopic applications. In vivo imaging of several different parts of a mouse demonstrates the excellent imaging ability of the probe.
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20
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Liu N, Yang S, Xing D. Photoacoustic and hyperspectral dual-modality endoscope. OPTICS LETTERS 2018; 43:138-141. [PMID: 29328216 DOI: 10.1364/ol.43.000138] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We have developed a dual-modality endoscope composed of photoacoustic (PA) and hyperspectral imaging, capable of visualizing both structural and functional properties of bio-tissue. The endoscope's composition and scanning mechanism was described, and the feasibility of the dual-modality endoscope was verified by mimic phantom experiments. Lately, we demonstrated its endoscopic workability through in vivo experiments. The experimental results showed that the proposed herein hybrid endoscope can provide optical imaging of the surface and tomography imaging for the deeper features, and a functional oxygen saturation rate map of the same imaging area. We demonstrated optical-resolution PA imaging of vascular structures and an oxygen saturation rate map in a rabbit's rectum. It confirmed that this dual-modality endoscope can play an important role in comprehensive clinical applications.
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Ansari R, Zhang EZ, Desjardins AE, Beard PC. All-optical forward-viewing photoacoustic probe for high-resolution 3D endoscopy. LIGHT, SCIENCE & APPLICATIONS 2018; 7:75. [PMID: 30323927 PMCID: PMC6177463 DOI: 10.1038/s41377-018-0070-5] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/29/2018] [Accepted: 08/30/2018] [Indexed: 05/03/2023]
Abstract
A miniature forward-viewing endoscopic probe that provides high-resolution 3D photoacoustic images is demonstrated. The probe is of outer diameter 3.2 mm and comprised of a transparent Fabry-Pérot (FP) polymer-film ultrasound sensor that is located at the distal end of a rigid optical fiber bundle. Excitation laser pulses are coupled simultaneously into all cores of the bundle and are transmitted through the FP sensor to provide wide-field tissue illumination at the distal end. The resulting photoacoustic waves are mapped in 2D by sequentially scanning the input end of the bundle with an interrogation laser beam in order to individually address different points on the FP sensor. In this way, the sensor acts as a high-density ultrasound array that is comprised of 50,000 individual elements, each of which is 12 µm in diameter, within the 3.2 mm diameter footprint of the probe. The fine spatial sampling that this affords, along with the wide bandwidth (f -3dB = 34 MHz) of the sensor, enables a high-resolution photoacoustic image to be reconstructed. The measured on-axis lateral resolution of the probe was depth-dependent and ranged from 45-170 µm for depths between 1 and 7 mm, and the vertical resolution was 31 µm over the same depth range. The system was evaluated by acquiring 3D images of absorbing phantoms and the microvascular anatomies of a duck embryo and mouse skin. Excellent image fidelity was demonstrated. It is anticipated that this type of probe could find application as a tool for guiding laparoscopic procedures, fetal surgery and other minimally invasive interventions that require a millimeter-scale forward-viewing 3D photoacoustic imaging probe.
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Affiliation(s)
- Rehman Ansari
- Department Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Charles Bell House, 67-73 Riding House Street, London, W1W 7EJ UK
| | - Edward Z. Zhang
- Department Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Charles Bell House, 67-73 Riding House Street, London, W1W 7EJ UK
| | - Adrien E. Desjardins
- Department Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Charles Bell House, 67-73 Riding House Street, London, W1W 7EJ UK
| | - Paul C. Beard
- Department Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Charles Bell House, 67-73 Riding House Street, London, W1W 7EJ UK
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Cai D, Li G, Xia D, Li Z, Guo Z, Chen SL. Synthetic aperture focusing technique for photoacoustic endoscopy. OPTICS EXPRESS 2017; 25:20162-20171. [PMID: 29041700 DOI: 10.1364/oe.25.020162] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Photoacoustic endoscopy (PAE) is a promising tool for the detection of atherosclerotic plaque. In this work, we propose a novel design of a side-viewing PAE probe based on a synthetic aperture focusing technique (SAFT) to enable high transverse resolution over large depth of focus (DOF) along the radial direction. A point-like ultrasonic detector is used to ensure a wide detection angle and thus a large synthetic aperture for SAFT. We first perform numerical simulation to optimize the PAE probe design, which involves the placement of the point-like detector and the diameter of a reflection rod mirror. Then, experiments are conducted based on the optimized probe design. High transverse resolution of 115-190 µm over large DOF of 3.5 mm along the radial direction is experimentally obtained. The SAFT-based PAE holds promise for endoscopic imaging with a high transverse resolution for both the surface and deep regions of tissue.
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Deán-Ben XL, Gottschalk S, Mc Larney B, Shoham S, Razansky D. Advanced optoacoustic methods for multiscale imaging of in vivo dynamics. Chem Soc Rev 2017; 46:2158-2198. [PMID: 28276544 PMCID: PMC5460636 DOI: 10.1039/c6cs00765a] [Citation(s) in RCA: 186] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Visualization of dynamic functional and molecular events in an unperturbed in vivo environment is essential for understanding the complex biology of living organisms and of disease state and progression. To this end, optoacoustic (photoacoustic) sensing and imaging have demonstrated the exclusive capacity to maintain excellent optical contrast and high resolution in deep-tissue observations, far beyond the penetration limits of modern microscopy. Yet, the time domain is paramount for the observation and study of complex biological interactions that may be invisible in single snapshots of living systems. This review focuses on the recent advances in optoacoustic imaging assisted by smart molecular labeling and dynamic contrast enhancement approaches that enable new types of multiscale dynamic observations not attainable with other bio-imaging modalities. A wealth of investigated new research topics and clinical applications is further discussed, including imaging of large-scale brain activity patterns, volumetric visualization of moving organs and contrast agent kinetics, molecular imaging using targeted and genetically expressed labels, as well as three-dimensional handheld diagnostics of human subjects.
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Affiliation(s)
- X L Deán-Ben
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
| | - S Gottschalk
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
| | - B Mc Larney
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany. and Faculty of Medicine, Technical University of Munich, Ismaninger Str. 22, 81675 Munich, Germany
| | - S Shoham
- Department of Biomedical Engineering, Technion - Israel Institute of Technology, 32000 Haifa, Israel
| | - D Razansky
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany. and Faculty of Medicine, Technical University of Munich, Ismaninger Str. 22, 81675 Munich, Germany
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