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Zhang J, Long X, Zhang G, Ma Z, Li W, Wang Y, Yang F, Lin R, Li C, Lam KH. Broadband transparent ultrasound transducer with polymethyl methacrylate as matching layer for in vivo photoacoustic microscopy. PHOTOACOUSTICS 2023; 33:100548. [PMID: 38021293 PMCID: PMC10658616 DOI: 10.1016/j.pacs.2023.100548] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/20/2023] [Accepted: 08/22/2023] [Indexed: 12/01/2023]
Abstract
Photoacoustic imaging (PAI) uniquely combines optics and ultrasound, presenting a promising role in biomedical imaging as a non-invasive and label-free imaging technology. As the traditional opaque ultrasound (US) transducers could hinder the transportation of the excitation light and limit the performance of PAI system, piezoelectric transparent ultrasonic transducers (TUTs) with indium tin oxide (ITO) electrodes have been developed to allow light transmission through the transducer and illuminate the sample directly. Nevertheless, without having transparent matching materials with appropriate properties, the bandwidth of those TUTs was generally narrow. In this work, we propose to employ polymethyl methacrylate (PMMA) as the matching layer material to improve the bandwidth of lithium niobate (LN)-based TUTs. The effects of PMMA matching layer on the performance of TUTs have been systematically studied. With the optimized PMMA matching layer, the very wide bandwidth of > 50 % could be achieved for the TUTs even with different transducer frequencies, leading to the great enhancement of axial resolution when compared to the similar reported work. In addition, the imaging performance of the developed TUT prototype has been evaluated in a PAI system and demonstrated by both phantom and in vivo small animal imaging.
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Affiliation(s)
- Jiaming Zhang
- Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Xing Long
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, China
| | - Guangjie Zhang
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, China
| | - Zhongtian Ma
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, China
| | - Wenzhao Li
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, China
| | - Yibing Wang
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, China
| | - Fan Yang
- Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Riqiang Lin
- Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Changhui Li
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, China
- National Biomedical Imaging Center, Peking University, Beijing 100871, China
| | - Kwok-Ho Lam
- Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
- Centre for Medical and Industrial Ultrasonics, James Watt School of Engineering, University of Glasgow, Glasgow, Scotland, UK
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García-Garrigós JJ, Cebrecos A, Navarro-Calvo JA, Camarena F. A fiber-coupled laser diode design for reflection mode optical resolution photoacoustic microscopy. ULTRASONICS 2023; 132:107008. [PMID: 37099938 DOI: 10.1016/j.ultras.2023.107008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/09/2023] [Accepted: 04/07/2023] [Indexed: 05/29/2023]
Abstract
Pulsed Laser Diodes (PLD) are compact and high pulse repetition rate laser sources that show a great potential for low-cost Optical Resolution Photoacoustic Microscopes (OR-PAM). Nevertheless, their non-uniform multimode laser beams are of low quality so that high lateral resolutions with tightly focused beams are difficult to realize at long focusing distances, as required for reflection mode OR-PAM devices of clinical application. A new strategy based on homogenizing and shaping the laser diode beam with a square-core multimode optical fiber allowed to attain competitive lateral resolutions while keeping one centimeter working distance. The theoretical expressions for the laser spot size, determining optical lateral resolution, and the depth of focus are also written for general multimode beams. An OR-PAM system was built in confocal reflection mode with a linear phased-array as the ultrasound receiver in order to test its performance, first, on a resolution test target and, afterwards, on ex vivo rabbit ears to show the system potential for subcutaneous imaging of blood vessels and hair follicles.
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Affiliation(s)
- Juan J García-Garrigós
- Instituto de Instrumentación para Imagen Molecular (i3M), CSIC - Universitat Politècnica de València, Camino de Vera S/N, 46022, València, Spain.
| | - Alejandro Cebrecos
- Instituto de Instrumentación para Imagen Molecular (i3M), CSIC - Universitat Politècnica de València, Camino de Vera S/N, 46022, València, Spain
| | - Javier A Navarro-Calvo
- Instituto de Instrumentación para Imagen Molecular (i3M), CSIC - Universitat Politècnica de València, Camino de Vera S/N, 46022, València, Spain
| | - Francisco Camarena
- Instituto de Instrumentación para Imagen Molecular (i3M), CSIC - Universitat Politècnica de València, Camino de Vera S/N, 46022, València, Spain
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Ahn J, Baik JW, Kim D, Choi K, Lee S, Park SM, Kim JY, Nam SH, Kim C. In vivo photoacoustic monitoring of vasoconstriction induced by acute hyperglycemia. PHOTOACOUSTICS 2023; 30:100485. [PMID: 37082618 PMCID: PMC10112177 DOI: 10.1016/j.pacs.2023.100485] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 03/19/2023] [Accepted: 03/29/2023] [Indexed: 05/03/2023]
Abstract
Postprandial hyperglycemia, blood glucose spikes, induces endothelial dysfunction, increasing cardiovascular risks. Endothelial dysfunction leads to vasoconstriction, and observation of this phenomenon is important for understanding acute hyperglycemia. However, high-resolution imaging of microvessels during acute hyperglycemia has not been fully developed. Here, we demonstrate that photoacoustic microscopy can noninvasively monitor morphological changes in blood vessels of live animals' extremities when blood glucose rises rapidly. As blood glucose level rose from 100 to 400 mg/dL following intraperitoneal glucose injection, heart/breath rate, and body temperature remained constant, but arterioles constricted by approximately -5.7 ± 1.1% within 20 min, and gradually recovered for another 40 min. In contrast, venular diameters remained within about 0.6 ± 1.5% during arteriolar constriction. Our results experimentally and statistically demonstrate that acute hyperglycemia produces transitory vasoconstriction in arterioles, with an opposite trend of change in blood glucose. These findings could help understanding vascular glucose homeostasis and the relationship between diabetes and cardiovascular diseases.
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Affiliation(s)
- Joongho Ahn
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Jin Woo Baik
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Donggyu Kim
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Karam Choi
- Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., Suwon 16678, Republic of Korea
| | - Seunghyun Lee
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Sung-Min Park
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Jin Young Kim
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Sung Hyun Nam
- Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., Suwon 16678, Republic of Korea
- Corresponding authors.
| | - Chulhong Kim
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Corresponding authors.
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Hofmann UA, Li W, Deán-Ben XL, Subochev P, Estrada H, Razansky D. Enhancing optoacoustic mesoscopy through calibration-based iterative reconstruction. PHOTOACOUSTICS 2022; 28:100405. [PMID: 36246932 PMCID: PMC9554813 DOI: 10.1016/j.pacs.2022.100405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/19/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
Optoacoustic mesoscopy combines rich optical absorption contrast with high spatial resolution at tissue depths beyond reach for microscopic techniques employing focused light excitation. The mesoscopic imaging performance is commonly hindered by the use of inaccurate delay-and-sum reconstruction approaches and idealized modeling assumptions. In principle, image reconstruction performance could be enhanced by simulating the optoacoustic signal generation, propagation, and detection path. However, for most realistic experimental scenarios, the underlying total impulse response (TIR) cannot be accurately modelled. Here we propose to capture the TIR by scanning of a sub-resolution sized absorber. Significant improvement of spatial resolution and depth uniformity is demonstrated over 3 mm range, outperforming delay-and-sum and model-based reconstruction implementations. Reconstruction performance is validated by imaging subcutaneous murine vasculature and human skin in vivo. The proposed experimental calibration and reconstruction paradigm facilitates quantitative inversions while averting complex physics-based simulations. It can readily be applied to other imaging modalities employing TIR-based reconstructions.
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Affiliation(s)
- Urs A.T. Hofmann
- Institute for Biomedical Engineering and Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Switzerland
| | - Weiye Li
- Institute for Biomedical Engineering and Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Switzerland
| | - Xosé Luís Deán-Ben
- Institute for Biomedical Engineering and Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Switzerland
| | - Pavel Subochev
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
| | - Héctor Estrada
- Institute for Biomedical Engineering and Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Switzerland
| | - Daniel Razansky
- Institute for Biomedical Engineering and Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Switzerland
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