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Hosseindokht Z, Davoudi S, Rahdar M, Janahmadi M, Kolahdouz M, Sasanpoour P. Photoacoustic viscoelasticity assessment of prefrontal cortex and cerebellum in normal and prenatal valproic acid-exposed rats. PHOTOACOUSTICS 2024; 36:100590. [PMID: 38318427 PMCID: PMC10839762 DOI: 10.1016/j.pacs.2024.100590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/11/2023] [Accepted: 01/18/2024] [Indexed: 02/07/2024]
Abstract
Mechanical properties of brain tissues are from principal features from different points of view; diagnosis, the performance of the brain and neurological disorders. Particularly viscoelastic properties of the brain tissues are determinative. In this study based on a proposed accurate and non-invasive method, we have measured the viscoelastic properties of prefrontal cortex and cerebellum, two important brain regions involved in motor learning and pathophysiology of autism spectrum disorder (ASD). In this regard, using photoacoustic systems, viscoelastic properties of tissues from the cerebellum and prefrontal cortex of normal and prenatal VPA (Valproic acid)-exposed (i.e. autistic-like) offspring rats are measured. Results of our study show that the cerebellums of normal tissues are stiffer than the tissue obtained from autistic-like rats, while the viscoelasticity of the prefrontal cortex of normal tissues is higher than that of autistic ones. The proposed method for the measurement of viscoelastic properties of the brain tissue has the potential not only for the fundamental studies but as a diagnosis technique.
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Affiliation(s)
- Zahra Hosseindokht
- School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Shima Davoudi
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mona Rahdar
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahyar Janahmadi
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammadreza Kolahdouz
- School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Pezhman Sasanpoour
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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2
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Lin R, Lv S, Lou W, Wang X, Xie Z, Zeng S, Chen R, Gao W, Jiang T, Cheng KWE, Lam KH, Gong X. In-vivo assessment of a rat rectal tumor using optical-resolution photoacoustic endoscopy. BIOMEDICAL OPTICS EXPRESS 2024; 15:2251-2261. [PMID: 38633094 PMCID: PMC11019702 DOI: 10.1364/boe.518204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 02/14/2024] [Accepted: 02/26/2024] [Indexed: 04/19/2024]
Abstract
Optical-resolution photoacoustic endoscopy (OR-PAE) has been proven to realize imaging on the vascular network in the gastrointestinal (GI) tract with high sensitivity and spatial resolution, providing morphological information. Various photoacoustic endoscopic catheters were developed to improve the resolution and adaptivity of in-vivo imaging. However, this technology has not yet been validated on in-vivo GI tumors, which generally feature angiogenesis. The tumor causes thickened mucosa and neoplasia, requiring large depth-of-field (DOF) in imaging, which contradicts to high-resolution imaging. In this work, a novel catheter was developed with a high resolution of ∼27 µm, providing a matched DOF of ∼400 µm to cover the vessels up to the submucosa layer. Optical-resolution photoacoustic endoscopic imaging was first performed on in-vivo rat rectal tumors. In addition, to further characterize the vessel morphology, tumor-suspected regions and normal regions were selected for quantification and analysis of vessel dimension distribution and tortuosity. All the results suggest that the OR-PAE has great application potential in tumor diagnosis, evaluation, and monitoring of therapeutic efficacy.
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Affiliation(s)
- Riqiang Lin
- Research Center for Biomedical Optics and Molecular Imaging, Key Laboratory of Biomedical Imaging Science and System, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518055, China
- Department of Electrical and Electronic Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, SAR, China
| | - Shengmiao Lv
- Research Center for Biomedical Optics and Molecular Imaging, Key Laboratory of Biomedical Imaging Science and System, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518055, China
- Shenzhen Key Laboratory for Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, CAS Key Laboratory of Health Informatics, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518055, China
| | - Wenjing Lou
- Department of Ultrasound Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiatian Wang
- Research Center for Biomedical Optics and Molecular Imaging, Key Laboratory of Biomedical Imaging Science and System, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518055, China
- Shenzhen Key Laboratory for Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, CAS Key Laboratory of Health Informatics, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518055, China
| | - Zhihua Xie
- Research Center for Biomedical Optics and Molecular Imaging, Key Laboratory of Biomedical Imaging Science and System, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518055, China
- Shenzhen Key Laboratory for Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, CAS Key Laboratory of Health Informatics, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518055, China
| | - Silue Zeng
- Research Center for Biomedical Optics and Molecular Imaging, Key Laboratory of Biomedical Imaging Science and System, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518055, China
| | - Rui Chen
- Research Center for Biomedical Optics and Molecular Imaging, Key Laboratory of Biomedical Imaging Science and System, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518055, China
| | - Wen Gao
- Research Center for Biomedical Optics and Molecular Imaging, Key Laboratory of Biomedical Imaging Science and System, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518055, China
| | - Tianan Jiang
- Department of Ultrasound Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Ka-Wai Eric Cheng
- Department of Electrical and Electronic Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, SAR, China
| | - Kwok-Ho Lam
- Department of Electrical and Electronic Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, SAR, China
- Centre for Medical and Industrial Ultrasonics, James Watt School of Engineering, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Xiaojing Gong
- Research Center for Biomedical Optics and Molecular Imaging, Key Laboratory of Biomedical Imaging Science and System, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518055, China
- Shenzhen Key Laboratory for Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, CAS Key Laboratory of Health Informatics, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518055, China
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Wang B, Zhong H, Zhang J, Jiang J, Xiao J. Thin flexible photoacoustic endoscopic probe with a distal-driven micro-step motor for pump-probe-based high-specific molecular imaging. OPTICS EXPRESS 2024; 32:8308-8320. [PMID: 38439489 DOI: 10.1364/oe.514282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 02/09/2024] [Indexed: 03/06/2024]
Abstract
Conventional photoacoustic endoscopy (PAE) is mostly for structural imaging, and its molecular imaging ability is quite limited. In this work, we address this issue and present the development of a flexible acoustic-resolution-based photoacoustic endoscopic (AR-PAE) probe with an outer diameter of 8 mm. This probe is driven by a micro-step motor at the distal end, enabling flexible and precise angular step control to synchronize with the optical parametric oscillator (OPO) lasers. This probe retains the high spatial resolution, high penetration depth, and spectroscopic imaging ability of conventional AR-PAE. Moreover, it is capable for background-free high-specific photoacoustic molecular imaging with a novel pump-probe detection technique, as demonstrated by the distribution visualizing of the FDA approved contrast agent methylene blue (MB) in an ex-vivo pig ileum. This proposed method represents an important technical advancement in multimodal PAE, and can potentially make considerable contributions across various biomedical fields.
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Liu L, Li A, Zhao Y, Zhu L, Zhao Y, Gao F. An umbrella-inspired snap-on robotic 3D photoacoustic endoscopic probe for augmented intragastric sensing: Proof of concept study. PHOTOACOUSTICS 2024; 35:100568. [PMID: 38312806 PMCID: PMC10835348 DOI: 10.1016/j.pacs.2023.100568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 11/01/2023] [Accepted: 11/03/2023] [Indexed: 02/06/2024]
Abstract
In this paper, we present a novel on-demand modular robotic photoacoustic tomography (PAT) probe integrated into an endoscopic device, potentially for deep intragastric sensing. The proposed solution offers a plug-and-play approach through the use of meso-scale steerable endoscopy and a new 'snap-on' 3D robotic PAT probe that can reconfigure the geometry of the intracorporeal light delivery, inspired by an umbrella structure. Specifically, using the limited esophageal access, steerable endoscopy allows navigation and advancement of a distally mounted robotic add-on for PAT that is folded until it reaches the deep-seated gastric lesion. Once the tip is positioned near the lesion site in the gastric cavity, there is ample working space for the robotic probe to adjust its umbrella-like unfolded shape. This allows fine-tuning of the laser delivery orientation of the fiber bundles to achieve the lesion-specific light delivery scheme. This design allows volumetric imaging of the intragastric PAT with enhanced sensitivity. To evaluate the performance of the modular robotic PAT probe, we performed a simulation analysis of the light intensity and ultrasound field distribution. The simulation results show that the robotic probe is feasible for intracorporeal PAT imaging. In addition, we printed a 3D model of a human stomach containing a simulated gastric tumour. Both the phantom and ex vivo experimental results validate the feasibility of the proposed robotic PAT probe.
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Affiliation(s)
- Li Liu
- Department of Electronic Engineering, The Chinese University of Hong Kong, 999077, Hong Kong, special administrative region, China
| | - Ang Li
- Department of Electronic Engineering, The Chinese University of Hong Kong, 999077, Hong Kong, special administrative region, China
| | - Yisong Zhao
- Department of Electronic Engineering, The Chinese University of Hong Kong, 999077, Hong Kong, special administrative region, China
- School of Information Science and Technology, ShanghaiTech University, No. 393 HuaXia Middle Road, Pudong New Dist., 201210, China
| | - Luyao Zhu
- School of Information Science and Technology, ShanghaiTech University, No. 393 HuaXia Middle Road, Pudong New Dist., 201210, China
| | - Yongjian Zhao
- Department of Electronic Engineering, The Chinese University of Hong Kong, 999077, Hong Kong, special administrative region, China
| | - Fei Gao
- School of Information Science and Technology, ShanghaiTech University, No. 393 HuaXia Middle Road, Pudong New Dist., 201210, China
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Li T, Chang TS, Shirazi A, Wu X, Lin WK, Zhang R, Guo JL, Oldham KR, Wang TD. Scaling down the dimensions of a Fabry-Perot polymer film acoustic sensor for photoacoustic endoscopy. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:S11514. [PMID: 38169937 PMCID: PMC10760494 DOI: 10.1117/1.jbo.29.s1.s11514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/17/2023] [Accepted: 12/06/2023] [Indexed: 01/05/2024]
Abstract
Significance A Fabry-Perot (FP) polymer film sensor can be used to detect acoustic waves in a photoacoustic endoscope (PAE) if the dimensions can be adequately scaled down in size. Current FP sensors have limitations in size, sensitivity, and array configurability. Aim We aim to characterize and demonstrate the imaging performance of a miniature FP sensor to evaluate the effects of reduced size and finite dimensions. Approach A transfer matrix model was developed to characterize the frequency response of a multilayer miniature FP sensor. An analytical model was derived to describe the effects of a substrate with finite thickness. Finite-element analysis was performed to characterize the temporal response of a sensor with finite dimensions. Miniature 2 × 2 mm 2 FP sensors were designed and fabricated using gold films as reflective mirrors on either side of a parylene C film deposited on a glass wafer. A single-wavelength laser was used to interrogate the sensor using illumination delivered by fiber subprobes. Imaging phantoms were used to verify FP sensor performance, and in vivo images of blood vessels were collected from a live mouse. Results The finite thickness substrate of the FP sensor resulted in echoes in the time domain signal that could be removed by back filtering. The substrate acted as a filter in the frequency domain. The finite lateral sensor dimensions produced side waves that could be eliminated by surface averaging using an interrogation beam with adequate diameter. The fabricated FP sensor produced a noise-equivalent pressure = 0.76 kPa, bandwidth of 16.6 MHz, a spectral full-width at-half-maximum = 0.2886 nm, and quality factor Q = 2694 . Photoacoustic images were collected from phantoms and blood vessels in a live mouse. Conclusions A miniature wafer-based FP sensor design has been demonstrated with scaled down form factor for future use in PAE.
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Affiliation(s)
- Tong Li
- University of Michigan, Department of Mechanical Engineering, Ann Arbor, Michigan, United States
| | - Tse-Shao Chang
- University of Michigan, Department of Mechanical Engineering, Ann Arbor, Michigan, United States
| | - Ahmad Shirazi
- University of Michigan, Division of Integrative Systems and Design, Ann Arbor, Michigan, United States
| | - Xiaoli Wu
- University of Michigan, Department of Internal Medicine, Division of Gastroenterology, Ann Arbor, Michigan, United States
| | - Wei-Kuan Lin
- University of Michigan, Department of Electrical and Computer Engineering, Ann Arbor, Michigan, United States
| | - Ruoliu Zhang
- University of Michigan, Department of Biomedical Engineering, Ann Arbor, Michigan, United States
| | - Jay L. Guo
- University of Michigan, Department of Mechanical Engineering, Ann Arbor, Michigan, United States
- University of Michigan, Department of Electrical and Computer Engineering, Ann Arbor, Michigan, United States
- University of Michigan, Department of Macromolecular Science and Engineering, Ann Arbor, Michigan, United States
- University of Michigan, Department of Applied Physics, Ann Arbor, Michigan, United States
| | - Kenn R. Oldham
- University of Michigan, Department of Mechanical Engineering, Ann Arbor, Michigan, United States
| | - Thomas D. Wang
- University of Michigan, Department of Mechanical Engineering, Ann Arbor, Michigan, United States
- University of Michigan, Department of Internal Medicine, Division of Gastroenterology, Ann Arbor, Michigan, United States
- University of Michigan, Department of Biomedical Engineering, Ann Arbor, Michigan, United States
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Hosseindokht Z, Kolahdouz M, Hajikhani B, Sasanpour P. Photoacoustic based evaluation of viscoelastic properties of Gram-negative and Gram-positive bacterial colonies. Sci Rep 2023; 13:14656. [PMID: 37670076 PMCID: PMC10480163 DOI: 10.1038/s41598-023-41663-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 08/29/2023] [Indexed: 09/07/2023] Open
Abstract
Mechanical properties of bacterial colonies are crucial considering both addressing their pathogenic effects and exploring their potential applications. Viscoelasticity is a key mechanical property with major impacts on the cell shapes and functions, which reflects the information about the cell envelope constituents. Hereby, we have proposed the application of photoacoustic viscoelasticity (PAVE) for studying the rheological properties of bacterial colonies. In this regard, we employed an intensity-modulated laser beam as the excitation source followed by the phase delay measurement between the generated PA signal and the reference for the characterization of colonies of two different types of Gram-positive and Gram-negative bacteria. The results of our study show that the colony of Staphylococcus aureus as Gram-positive bacteria has a significantly higher viscoelasticity ratio compared to that value for Acinetobacter baumannii as Gram-negative bacteria (77% difference). This may be due to the differing cell envelope structure between the two species, but we cannot rule out effects of biofilm formation in the colonies. Furthermore, a lumped model has been provided for the mechanical properties of bacterial colonies.
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Affiliation(s)
- Zahra Hosseindokht
- School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Mohammadreza Kolahdouz
- School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran.
| | - Bahareh Hajikhani
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Pezhman Sasanpour
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Guo T, Xiong K, Yuan B, Zhang Z, Wang L, Zhang Y, Liang C, Liu Z. Homogeneous-resolution photoacoustic microscopy for ultrawide field-of-view neurovascular imaging in Alzheimer's disease. PHOTOACOUSTICS 2023; 31:100516. [PMID: 37313359 PMCID: PMC10258506 DOI: 10.1016/j.pacs.2023.100516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 05/25/2023] [Accepted: 05/25/2023] [Indexed: 06/15/2023]
Abstract
Neurovascular imaging is essential for investigating neurodegenerative diseases. However, the existing neurovascular imaging technology suffers from a trade-off between a field of view (FOV) and resolution in the whole brain, resulting in an inhomogeneous resolution and lack of information. Here, homogeneous-resolution arched-scanning photoacoustic microscopy (AS-PAM), which has an ultrawide FOV to cover the entire mouse cerebral cortex, was developed. Imaging of the neurovasculature was performed with a homogenous resolution of 6.9 µm from the superior sagittal sinus to the middle cerebral artery and caudal rhinal vein in an FOV of 12 × 12 mm2. Moreover, using AS-PAM, vascular features of the meninges and cortex were quantified in early Alzheimer's disease (AD) and wild-type (WT) mice. The results demonstrated high sensitivity to the pathological progression of AD on tortuosity and branch index. The high-fidelity imaging capability in large FOV enables AS-PAM to be a promising tool for precise brain neurovascular visualization and quantification.
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Affiliation(s)
- Ting Guo
- School of Medicine South China University of Technology, Guangzhou 510006, China
- Department of Radiology, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 510080, China
- Guangdong Provincial Key Laboratory of Artificial Intelligence in Medical Image Analysis and Application, Guangzhou 510080, China
| | - Kedi Xiong
- MOE Key Laboratory of Laser Life Science Institute of Laser Life Science, South China Normal University, Guangzhou 510631, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Bo Yuan
- MOE Key Laboratory of Laser Life Science Institute of Laser Life Science, South China Normal University, Guangzhou 510631, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Zhenhui Zhang
- MOE Key Laboratory of Laser Life Science Institute of Laser Life Science, South China Normal University, Guangzhou 510631, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Lijuan Wang
- Department of Radiology, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 510080, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangzhou 510080, China
| | - Yuhu Zhang
- Department of Radiology, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 510080, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangzhou 510080, China
| | - Changhong Liang
- Department of Radiology, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 510080, China
- Guangdong Provincial Key Laboratory of Artificial Intelligence in Medical Image Analysis and Application, Guangzhou 510080, China
| | - Zaiyi Liu
- Department of Radiology, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 510080, China
- Guangdong Provincial Key Laboratory of Artificial Intelligence in Medical Image Analysis and Application, Guangzhou 510080, China
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Xie Z, Liu J, Ren Y, Huang J, Lin R, Wang X, Tan Q, Lv S, Song L, Liu C, Ma T, Gong X. Circular array transducer based-photoacoustic/ultrasonic endoscopic imaging with tunable ring-beam excitation. PHOTOACOUSTICS 2023; 29:100441. [PMID: 36606259 PMCID: PMC9807825 DOI: 10.1016/j.pacs.2022.100441] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 12/18/2022] [Indexed: 06/17/2023]
Abstract
Photoacoustic/ultrasound endoscopic imaging is regarded as an effective method to achieve accurate detection of intestinal disease by offering both the functional and structural information, simultaneously. Compared to the conventional endoscopy with single transducer and laser spot for signal detection and optical excitation, photoacoustic/ultrasound endoscopic probe using circular array transducer and ring-shaped laser beam avoids the instability brought by the mechanical scanning point-to-point, offering the dual-modality imaging with high accuracy and efficiency. Meanwhile, considering the complex morphological environments of intestinal tracts in clinics, developing the probe having sufficient wide imaging distance range is especially important. In this work, we develop a compact circular photoacoustic/ultrasonic endoscopic probe, using the group of fiber, lens and home-made axicon, to generate relatively concentrated ring-shaped laser beam for 360° excitation with high efficiency. Furthermore, the laser ring size can be tuned conveniently by changing the fiber-lens distance to ensure the potential applicability of the probe in various and complex morphological environments of intestines. Phantom experimental results demonstrate imaging distance range wide enough to cover from 12 mm to 30 mm. In addition, the accessibility of the photoacoustic signals of molecular probes in ex vivo experiments at the tissue depth of 7 mm using excitation energy of 5 mJ has also been demonstrated, showing a high optical excitation efficiency of the probe.
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Affiliation(s)
- Zhihua Xie
- Research Laboratory for Biomedical Optics and Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Jiamei Liu
- CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Yaguang Ren
- Research Laboratory for Biomedical Optics and Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Jiqing Huang
- CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Riqiang Lin
- Research Laboratory for Biomedical Optics and Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Xiatian Wang
- Research Laboratory for Biomedical Optics and Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Qingyuan Tan
- CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Shengmiao Lv
- Research Laboratory for Biomedical Optics and Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Liang Song
- Research Laboratory for Biomedical Optics and Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Chengbo Liu
- Research Laboratory for Biomedical Optics and Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Teng Ma
- CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Xiaojing Gong
- Research Laboratory for Biomedical Optics and Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
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9
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Compressed Sensing Photoacoustic Imaging Reconstruction Using Elastic Net Approach. Mol Imaging 2022; 2022:7877049. [PMID: 36721731 PMCID: PMC9881674 DOI: 10.1155/2022/7877049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/04/2022] [Accepted: 12/10/2022] [Indexed: 12/24/2022] Open
Abstract
Photoacoustic imaging involves reconstructing an estimation of the absorbed energy density distribution from measured ultrasound data. The reconstruction task based on incomplete and noisy experimental data is usually an ill-posed problem that requires regularization to obtain meaningful solutions. The purpose of the work is to propose an elastic network (EN) model to improve the quality of reconstructed photoacoustic images. To evaluate the performance of the proposed method, a series of numerical simulations and tissue-mimicking phantom experiments are performed. The experiment results indicate that, compared with the L 1-norm and L 2-normbased regularization methods with different numerical phantoms, Gaussian noise of 10-50 dB, and different regularization parameters, the EN method with α = 0.5 has better image quality, calculation speed, and antinoise ability.
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10
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Liang Y, Fu W, Li Q, Chen X, Sun H, Wang L, Jin L, Huang W, Guan BO. Optical-resolution functional gastrointestinal photoacoustic endoscopy based on optical heterodyne detection of ultrasound. Nat Commun 2022; 13:7604. [PMID: 36494360 PMCID: PMC9734171 DOI: 10.1038/s41467-022-35259-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 11/24/2022] [Indexed: 12/13/2022] Open
Abstract
Photoacoustic endoscopy shows promise in the detection of gastrointestinal cancer, inflammation, and other lesions. High-resolution endoscopic imaging of the hemodynamic response necessitates a small-sized, high-sensitivity ultrasound sensor. Here, we utilize a laser ultrasound sensor to develop a miniaturized, optical-resolution photoacoustic endoscope. The sensor can boost the acoustic response by a gain factor of ωo/Ω (the frequency ratio of the signal light and measured ultrasound) by measuring the acoustically induced optical phase change. As a result, we achieve a noise-equivalent pressure density (NEPD) below 1.5 mPa·Hz-1/2 over the measured range of 5 to 25 MHz. The heterodyne phase detection using dual-frequency laser beams of the sensor can offer resistance to thermal drift and vibrational perturbations. The endoscope is used to in vivo image a rat rectum and visualize the oxygen saturation changes during acute inflammation, which can hardly be observed with other imaging modalities.
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Affiliation(s)
- Yizhi Liang
- grid.258164.c0000 0004 1790 3548Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, China
| | - Wubing Fu
- grid.258164.c0000 0004 1790 3548Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, China
| | - Qiang Li
- grid.258164.c0000 0004 1790 3548Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, China
| | - Xiaolong Chen
- grid.258164.c0000 0004 1790 3548Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, China
| | - Huojiao Sun
- grid.258164.c0000 0004 1790 3548Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, China
| | - Lidai Wang
- grid.35030.350000 0004 1792 6846Department of Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR China
| | - Long Jin
- grid.258164.c0000 0004 1790 3548Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, China
| | - Wei Huang
- grid.258164.c0000 0004 1790 3548Department of Gastroenterology, the First Affiliated Hospital, Jinan University, Guangzhou, Guangdong China
| | - Bai-Ou Guan
- grid.258164.c0000 0004 1790 3548Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, China
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11
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Xiao J, Jiang J, Zhang J, Wang Y, Wang B. Acoustic-resolution-based spectroscopic photoacoustic endoscopy towards molecular imaging in deep tissues. OPTICS EXPRESS 2022; 30:35014-35028. [PMID: 36242503 DOI: 10.1364/oe.469550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/22/2022] [Indexed: 06/16/2023]
Abstract
Due to many technical difficulties, the study of molecular photoacoustic endoscopic (PAE) imaging in deep tissues is limited. In this work, we have set up a multimodal acoustic-resolution-based PAE (AR-PAE) system to image the rabbit rectum and preliminarily explored the potential of molecular PAE for deep-seated targets in proof-of-concept. We developed an improved back-projection (IBP) algorithm for focused detection over the centimeter-scale imaging depth. We also developed a deep-learning-based algorithm to remove the electrical noise from the step motor to prevent data averaging for reduced scanning time. We injected a dose of indocyanine green (ICG) near the rabbit rectum and compared 2D and 3D photoacoustic/ultrasound (PA/US) images at different wavelengths. We proposed incorporating a small camera to guide the slow PA/US endoscopic scan. Results show that this system has achieved a lateral resolution of about 0.77/0.65 mm for PA/US images with a signal-to-noise ratio (SNR) of 25/38 dB at an imaging depth of 1.4 cm. We found that the rectum wall and the ICG can be well distinguished spectroscopically. Results also show that the PA images at 532 nm have higher signal intensity and reflection artifacts from pelvic tendons and bones than those at longer wavelengths such as 800 nm. The proposed methods and the intuitive findings in this work may guide and promote the development of high-penetration molecular PAE.
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12
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Design and Fabrication of a Tunable Optofluidic Microlens Driven by an Encircled Thermo-Pneumatic Actuator. MICROMACHINES 2022; 13:mi13081189. [PMID: 36014111 PMCID: PMC9415834 DOI: 10.3390/mi13081189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 06/26/2022] [Accepted: 06/30/2022] [Indexed: 11/17/2022]
Abstract
This paper presents the design, simulation, fabrication, assembly, and testing of a miniature thermo-pneumatic optofluidic lens. The device comprises two separate zones for air heating and fluid pressing on a flexible membrane. A buried three-dimensional spiral microchannel connects the two zones without pumps or valves. The three-dimensional microfluidic structure is realized using a high-resolution three-dimensional printing technique. Multi-physics finite element simulations are introduced to assess the optimized air chamber design and the low-temperature gradient of the optical liquid. The tunable lens can be operated using a direct-current power supply. The temperature change with time is measured using an infrared thermal imager. The focal length ranges from 5 to 23 mm under a maximum voltage of 6 V. Because of the small size and robust actuation scheme, the device can potentially be integrated into miniature micro-optics devices for the fine-tuning of focal lengths.
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13
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Kim K, Youm JY, Lee EH, Gulenko O, Kim M, Yoon BH, Jeon M, Kim TH, Ha YS, Yang JM. Tapered catheter-based transurethral photoacoustic and ultrasonic endoscopy of the urinary system. OPTICS EXPRESS 2022; 30:26169-26181. [PMID: 36236812 DOI: 10.1364/oe.461855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 06/13/2022] [Indexed: 06/16/2023]
Abstract
Early diagnosis is critical for treating bladder cancer, as this cancer is very aggressive and lethal if detected too late. To address this important clinical issue, a photoacoustic tomography (PAT)-based transabdominal imaging approach was suggested in previous reports, in which its in vivo feasibility was also demonstrated based on a small animal model. However, successful translation of this approach to real clinical settings would be challenging because the human bladder is located at a depth that far exceeds the typical penetration depth of PAT (∼3 cm for in vivo cases). In this study, we developed a tapered catheter-based, transurethral photoacoustic and ultrasonic endoscopic probe with a 2.8 mm outer diameter to investigate whether the well-known benefits of PAT can be harnessed to resolve unmet urological issues, including early diagnosis of bladder cancer. To demonstrate the in vivo imaging capability of the proposed imaging probe, we performed a rabbit model-based urinary system imaging experiment and acquired a 3D microvasculature map distributed in the wall of the urinary system, which is a first in PAT, to the best of our knowledge. We believe that the results strongly support the use of this transurethral imaging approach as a feasible strategy for addressing urological diagnosis issues.
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14
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Cheng Y, Li Z, Chen C, Cao J, Bao C, Ning Y, Hao Q. Varifocal liquid lens driven by a conical dielectric elastomer actuator. APPLIED OPTICS 2022; 61:4633-4637. [PMID: 36256307 DOI: 10.1364/ao.457886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/03/2022] [Indexed: 06/16/2023]
Abstract
A varifocal lens is an important part of optical systems with applications in biomedicine, photography, smartphones, and virtual reality. In this paper, we propose and demonstrate a varifocal liquid lens driven by a conical dielectric elastomer actuator. When the conical dielectric elastomer is subjected to an actuation voltage, the conical dielectric elastomer works as an out-plane actuator and makes the surface curvature of the liquid droplet increase; then the focal length of the proposed varifocal liquid lens changes. The overall dimensions of the proposed varifocal liquid lens are 9.4 mm in diameter and 12.5 mm in height. The focal length tuning range is 15.07mm∼9.50mm when the actuation voltage increases from 0 kV to 5.0 kV. The focal power variation of the proposed varifocal liquid lens is 35.5 D. The rise and fall times of the proposed varifocal liquid lens are 215 ms and 293 ms, respectively. The ability of the proposed liquid lens to focus on objects at different distances without any moving parts is demonstrated. The compact varifocal liquid lens driven by the conical dielectric elastomer actuator in the current study has the potential to be used in various compact imaging systems in the future.
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15
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Abstract
Photoacoustic (PA) imaging is able to provide extremely high molecular
contrast while maintaining the superior imaging depth of ultrasound (US)
imaging. Conventional microscopic PA imaging has limited access to deeper tissue
due to strong light scattering and attenuation. Endoscopic PA technology enables
direct delivery of excitation light into the interior of a hollow organ or
cavity of the body for functional and molecular PA imaging of target tissue.
Various endoscopic PA probes have been developed for different applications,
including the intravascular imaging of lipids in atherosclerotic plaque and
endoscopic imaging of colon cancer. In this paper, the authors review
representative probe configurations and corresponding preclinical applications.
In addition, the potential challenges and future directions of endoscopic PA
imaging are discussed.
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Affiliation(s)
- Yan Li
- Beckman Laser Institute, University of California Irvine,
Irvine, CA 92617, USA
| | - Gengxi Lu
- Roski Eye Institute, Keck School of Medicine, University of
Southern California, Los Angeles, CA 90033, USA
| | - Qifa Zhou
- Roski Eye Institute, Keck School of Medicine, University of
Southern California, Los Angeles, CA 90033, USA
| | - Zhongping Chen
- Beckman Laser Institute, University of California Irvine,
Irvine, CA 92617, USA
- The Edwards Lifesciences Center for Cardiovascular
Technology, University of California Irvine, Irvine, CA 92617, USA
- Department of Biomedical Engineering, University of
California Irvine, Irvine, CA 92697, USA
- Correspondence:
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16
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Fu B, Cheng Y, Shang C, Li J, Wang G, Zhang C, Sun J, Ma J, Ji X, He B. Optical ultrasound sensors for photoacoustic imaging: a narrative review. Quant Imaging Med Surg 2022; 12:1608-1631. [PMID: 35111652 DOI: 10.21037/qims-21-605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/23/2021] [Indexed: 11/06/2022]
Abstract
Optical ultrasound sensors have been increasingly employed in biomedical diagnosis and photoacoustic imaging (PAI) due to high sensitivity and resolution. PAI could visualize the distribution of ultrasound excited by laser pulses in biological tissues. The information of tissues is detected by ultrasound sensors in order to reconstruct structural images. However, traditional ultrasound transducers are made of piezoelectric films that lose sensitivity quadratically with the size reduction. In addition, the influence of electromagnetic interference limits further applications of traditional ultrasound transducers. Therefore, optical ultrasound sensors are developed to overcome these shortcomings. In this review, optical ultrasound sensors are classified into resonant and non-resonant ones in view of physical principles. The principles and basic parameters of sensors are introduced in detail. Moreover, the state of the art of optical ultrasound sensors and applications in PAI are also presented. Furthermore, the merits and drawbacks of sensors based on resonance and non-resonance are discussed in perspectives. We believe this review could provide researchers with a better understanding of the current status of optical ultrasound sensors and biomedical applications.
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Affiliation(s)
- Bo Fu
- BUAA-CCMU Advanced Innovation Center for Big Data-Based Precision Medicine, School of Engineering Medicine, Beihang University, Beijing, China.,School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China.,Key Laboratory of Big Data-Based Precision Medicine, Ministry of Industry and Information Technology, Interdisciplinary Innovation Institute of Medicine and Engineering, Beihang University, Beijing, China
| | - Yuan Cheng
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Ce Shang
- BUAA-CCMU Advanced Innovation Center for Big Data-Based Precision Medicine, School of Engineering Medicine, Beihang University, Beijing, China.,School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Jing Li
- BUAA-CCMU Advanced Innovation Center for Big Data-Based Precision Medicine, School of Engineering Medicine, Beihang University, Beijing, China.,School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Gang Wang
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Chenghong Zhang
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Jingxuan Sun
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Jianguo Ma
- BUAA-CCMU Advanced Innovation Center for Big Data-Based Precision Medicine, School of Engineering Medicine, Beihang University, Beijing, China.,School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China.,Key Laboratory of Big Data-Based Precision Medicine, Ministry of Industry and Information Technology, Interdisciplinary Innovation Institute of Medicine and Engineering, Beihang University, Beijing, China
| | - Xunming Ji
- Neurosurgery Department of Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Boqu He
- BUAA-CCMU Advanced Innovation Center for Big Data-Based Precision Medicine, School of Engineering Medicine, Beihang University, Beijing, China.,School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
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17
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Kim J, Ahn J, Kang G, Hwang JH, Kim C. High-resolution photoacoustic/ultrasound imaging of the porcine stomach wall: an ex vivo feasibility study. BIOMEDICAL OPTICS EXPRESS 2021; 12:6717-6729. [PMID: 34858676 PMCID: PMC8606154 DOI: 10.1364/boe.441241] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/22/2021] [Accepted: 09/22/2021] [Indexed: 05/05/2023]
Abstract
Photoacoustic (PA) imaging has become invaluable in preclinical and clinical research. Endoscopic PA imaging in particular has been explored as a noninvasive imaging modality to view vasculature and diagnose cancers in the digestive system. However, these feasibility studies are still limited to rodents or rabbits. Here, we develop a fully synchronized simultaneous ultrasound and photoacoustic microscopy system using two spectral bands (i.e., the visible and near-infrared) in both optical- and acoustic-resolution modes. We investigate the feasibility of imaging gastric vasculature in an ex vivo porcine model. The entire gastric wall, including the mucosa, submucosa, muscularis propria, and serosa, was excised from fresh porcine stomachs immediately followed by ultrasound and PA imaging being performed within a few hours of sacrifice. PA images of the mucosal vasculature were obtained at depths of 1.90 mm, which is a clinically significant accomplishment considering that the average thickness of the human mucosa is 1.26 mm. The layer structure of the stomach wall could be clearly distinguished in the overlaid PA and US images. Because gastric cancer starts from the mucosal surface and infiltrates into the submucosa, PA imaging can cover a clinically relevant depth in early gastric cancer diagnosis. We were able to detect mucosal vasculature in the entire mucosal layer, suggesting the potential utility of combined PA/US imaging in gastroenterology.
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Affiliation(s)
- Jaewoo Kim
- Department of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
- These authors have contributed equally
| | - Joongho Ahn
- Department of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
- These authors have contributed equally
| | - Gwansuk Kang
- Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Joo Ha Hwang
- Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Chulhong Kim
- Department of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
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18
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Cheng Y, Chen C, Cao J, Bao C, Yang A, Hao Q. Tunable lens using dielectric elastomer sandwiched by transparent conductive liquid. OPTICS LETTERS 2021; 46:4430-4433. [PMID: 34470033 DOI: 10.1364/ol.437644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 08/16/2021] [Indexed: 06/13/2023]
Abstract
We propose and demonstrate a compact tunable lens with high transmittance using a dielectric elastomer sandwiched by transparent conductive liquid. The transparent conductive liquid not only serves as the refractive material of the tunable lens but also works as the compliant electrode of the dielectric elastomer. The overall dimensions of the proposed tunable lens are 16 mm in diameter and 10 mm in height, and the optical transmittance is as high as 92.2% at 380-760 nm. The focal power variation of the tunable lens is -23.71D at an actuation voltage of 3.0 kV. The rise and fall times are 60 ms and 185 ms, respectively. The fabrication process of the tunable lens is free of the deposition of opaque compliant electrodes. Such a tunable lens promises a potential solution in various compact imaging systems.
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19
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Yang W, Zhou J, Shao W, Seong M, He P, Ye Z, Guo Z, Jing L, Chen SL. Photoacoustic-fluorescence microendoscopy in vivo. OPTICS LETTERS 2021; 46:2340-2343. [PMID: 33988578 DOI: 10.1364/ol.425753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
A miniature endoscope capable of imaging multiple tissue contrasts in high resolution is highly attractive, because it can provide complementary and detailed tissue information of internal organs. Here we present a photoacoustic (PA)-fluorescence (FL) endoscope for optical-resolution PA microscopy (PAM) and FL microscopy (FLM). The endoscope with a diameter of 2.8 mm achieves high lateral resolutions of 5.5 and 6.3 µm for PAM and FLM modes, respectively. In vivo imaging of zebrafish larvae and a mouse ear is conducted, and high-quality images are obtained. Additionally, in vivo endoscopic imaging of a rat rectum is demonstrated, showing the endoscopic imaging capability of our endoscope. By providing dual contrasts with high resolution, the endoscope may open up new opportunities for clinical endoscopic imaging applications.
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20
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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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21
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Zhou J, Jokerst JV. Photoacoustic imaging with fiber optic technology: A review. PHOTOACOUSTICS 2020; 20:100211. [PMID: 33163358 PMCID: PMC7606844 DOI: 10.1016/j.pacs.2020.100211] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/05/2020] [Accepted: 09/19/2020] [Indexed: 05/03/2023]
Abstract
Photoacoustic imaging (PAI) has achieved remarkable growth in the past few decades since it takes advantage of both optical and ultrasound (US) imaging. In order to better promote the wide clinical applications of PAI, many miniaturized and portable PAI systems have recently been proposed. Most of these systems utilize fiber optic technologies. Here, we overview the fiber optic technologies used in PAI. This paper discusses three different fiber optic technologies: fiber optic light transmission, fiber optic US transmission, and fiber optic US detection. These fiber optic technologies are analyzed in different PAI modalities including photoacoustic microscopy (PAM), photoacoustic computed tomography (PACT), and minimally invasive photoacoustic imaging (MIPAI).
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Affiliation(s)
- Jingcheng Zhou
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92092, USA
| | - Jesse V. Jokerst
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92092, USA
- Materials Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92092, USA
- Department of Radiology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92092, USA
- Corresponding author at: Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92092, USA.
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22
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Jin H, Zheng Z, Liu S, Zheng Y. Evaluation of Reconstruction Methodology for Helical Scan Guided Photoacoustic Endoscopy. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:4198-4208. [PMID: 32755852 DOI: 10.1109/tmi.2020.3014410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Photoacoustic endoscopy (PAE), combining both advantages of optical contrast and acoustic resolution, can visualize the chemical-specific optical information of tissues inside human-body. Recently, its corresponding reconstruction methods have been extensively researched. However, most of them are limited on cylindrical scan trajectories, rather than a helical scan which is more clinically practical. On this note, this article proposes a methodology of imaging reconstruction and evaluation for helical scan guided PAE. Different from traditional reconstruction method, synthetic aperture focusing technique (SAFT), our method reconstructs image using wavefield extrapolation which significantly improves computational efficiency and even takes only 0.25 seconds for 3-D reconstructions. In addition, the proposed evaluation methodology can estimate the resolutions and deviations of reconstructed images in advance, and then can be used to optimize the PAE scan parameters. Groups of simulations as well as ex-vivo experiments with different scan parameters are provided to fully demonstrate the performance of the proposed techniques. The quantitatively measured angular resolutions and deviations agree well with our theoretical derivation results D√{rs2 +h2} / [1.25(rs rd +h2)] (rad) and -h l / (rs rd +h2) (rad), respectively D,rd, rs,h and l represent transducer diameter, radius of scan trajectory, radius of source position, unit helical pitch and the distance from targets to helical scan plane, respectively). This theoretical result also suits for circular and cylindrical scan in case of h = 0 .
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23
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Guo H, Li Y, Qi W, Xi L. Photoacoustic endoscopy: A progress review. JOURNAL OF BIOPHOTONICS 2020; 13:e202000217. [PMID: 32935920 DOI: 10.1002/jbio.202000217] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/20/2020] [Accepted: 08/31/2020] [Indexed: 06/11/2023]
Abstract
Endoscopy has been widely used in biomedical imaging and integrated with various optical and acoustic imaging modalities. Photoacoustic imaging (PAI), one of the fastest growing biomedical imaging modalities, is a noninvasive and nonionizing method that owns rich optical contrast, deep acoustic penetration depth, multiscale and multiparametric imaging capability. Hence, it is preferred to miniaturize the volume of PAI and develop an emerged endoscopic imaging modality referred to as photoacoustic endoscopy (PAE). It has been developed for more than one decade since the first report of PAE. Unfortunately, until now, there is no mature photoacoustic endoscopic technique recognized in clinic due to various technical limitations. To address this concern, recent development of new scanning mechanisms, adoption of novel optical/acoustic devices, utilization of superior computation methods and exploration of multimodality strategies have significantly promoted the progress of PAE toward clinic. In this review, we comprehensively reviewed recent progresses in single- and multimodality PAE with new physics, mechanisms and strategies to achieve practical devices for potential applicable scenarios including esophageal, gastrointestinal, urogenital and intravascular imaging. We ended this review with challenges and prospects for future development of PAE.
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Affiliation(s)
- Heng Guo
- School of Physics, University of Electronic Science and Technology of China, Chengdu, China
| | - Ying Li
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Weizhi Qi
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Lei Xi
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
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24
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Lu C, Xiong K, Ma Y, Zhang W, Cheng Z, Yang S. Electrothermal-MEMS-induced nonlinear distortion correction in photoacoustic laparoscopy. OPTICS EXPRESS 2020; 28:15300-15313. [PMID: 32403561 DOI: 10.1364/oe.392493] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 04/25/2020] [Indexed: 05/18/2023]
Abstract
Micro-electro-mechanical systems (MEMS) scanner has significant advantages of miniature size, fast response and high stability, which is particularly applicable to photoacoustic laparoscopy (PAL). However, tilt angle-voltage curve of electrothermal MEMS shows a nonlinear character, which leads to inevitable nonlinear distortion in photoacoustic imaging. To overcome this problem, a nonlinear distortion correction was developed for the high-resolution forward-scanning electrothermal-MEMS-based PAL. The adaptive resampling method (ARM) was introduced to adaptively calibrate the projection of non-uniform scanning region to match the uniform scanning region. The correction performed low time complexity and high portability owing to the adaptive capacity of distortion decomposition in the reconstruction of physical models. Compared with the sample structure, phantom experiments demonstrated that the distortion was calibrated in all directions and the corrected image provided up to 96.82% high structural similarity in local subset. Furthermore, ARM was applied to imaging the abdominal cavity of rat and the vascular morphology was corrected in real-time display within a delay less than 2 seconds. All these results demonstrated that the nonlinear distortion correction possessed timely and effective correction in PAL, which suggested that it had the potential to employ to any other electrothermal-MEMS-based photoacoustic imaging systems for accurate and quantitative functional imaging.
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25
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Sangha GS, Goergen CJ. Label-free photoacoustic and ultrasound imaging for murine atherosclerosis characterization. APL Bioeng 2020; 4:026102. [PMID: 32266325 PMCID: PMC7127913 DOI: 10.1063/1.5142728] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/09/2020] [Indexed: 12/24/2022] Open
Abstract
Dual-modality photoacoustic tomography (PAT) and 4D ultrasound (4DUS) imaging have shown promise for cardiovascular applications, but their use in murine atherosclerosis imaging is limited. This study used PAT and 4DUS to correlate altered arterial strain and hemodynamics to morphological changes and lipid localization in a murine partial carotid ligation (PCL) model of atherosclerosis. Validation experiments showed a positive correlation between the PAT signal-to-noise ratio and plaque lipid composition obtained from oil-red O histology. Cross-sectional in situ PAT and longitudinal in vivo ultrasound imaging was performed using a 40 MHz transducer. Ultrasound timepoints included days 0, 1, 4, 7, 10, and 14 for hemodynamic and strain assessment, and 1100 nm and 1210 nm PAT was implemented at the study end point for hemoglobin and lipid characterization. These study groups were then separated into day 4 post-PCL with (n = 5) and without (n = 6) Western diet feeding, as well as days 7 (n = 8), 10 (n = 8), and 14 (n = 8) post-PCL, in addition to a sham control group on a Western diet (n = 5). Overall, our data revealed a substantial decrease in left carotid artery pulsatility by day 7. The hemodynamic results suggested greater disturbed flow in the caudal regions resulting in earlier vessel stenosis and greater lipid deposition than cranial regions. Morphological and compositional data revealed heterogeneous vascular remodeling between days 0 and 7, with a rapid decrease in the vessel volume/length and the presence of both intraplaque hematoma and lipid deposition at day 10 post-PCL. These results highlight the utility of utilizing dual-modality PAT and 4DUS to study atherosclerosis progression.
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Affiliation(s)
- Gurneet S Sangha
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Dr., West Lafayette, Indiana 47907, USA
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26
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Li G, Ye Z, Liang S, Chen SL. Miniature probe for dual-modality photoacoustic microscopy and white-light microscopy for image guidance: A prototype toward an endoscope. JOURNAL OF BIOPHOTONICS 2020; 13:e201960200. [PMID: 31920005 DOI: 10.1002/jbio.201960200] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/22/2019] [Accepted: 12/23/2019] [Indexed: 05/11/2023]
Abstract
In this study, a novel photoacoustic microscopy (PAM) probe integrating white-light microscopy (WLM) modality that provides guidance for PAM imaging and complementary information is implemented. One single core of an imaging fiber bundle is employed to deliver a pulsed laser for photoacoustic excitation for PAM mode, which provides high resolution with deep penetration. Meanwhile, for WLM mode, the imaging fiber bundle is used to transmit two-dimensional superficial images. Lateral resolution of 7.2 μm for PAM is achieved. Since miniature components are used, the probe diameter is only 1.7 mm. Imaging of phantom and animals in vivo is conducted to show the imaging capability of the probe. The probe has several advantages by introducing the WLM mode, such as being able to conveniently identify regions of interest and align the focus for PAM mode. The prototype of an endoscope shows potential to facilitate clinical photoacoustic endoscopic applications.
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Affiliation(s)
- Guangyao Li
- University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai, China
| | - Zhanhong Ye
- University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai, China
| | - Siqi Liang
- University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai, China
| | - Sung-Liang Chen
- University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai, China
- State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai, China
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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: 16] [Impact Index Per Article: 3.2] [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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Ultrathin Tunable Lens Based on Boundary Tension Effect. SENSORS 2019; 19:s19184018. [PMID: 31540368 PMCID: PMC6767671 DOI: 10.3390/s19184018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 09/09/2019] [Accepted: 09/12/2019] [Indexed: 12/12/2022]
Abstract
Solid and liquid lenses are commonly used in optical design. Such lenses have suitable thicknesses due to their working principle and processing mode. Thus, zoom optical systems comprising solid and liquid lenses are extremely large. This work presents a new ultrathin tunable lens (UTL) comprising two liquid film lenses (LFLs) obtained through aspheric deformation and produced from the surface of a micro-liquid under gravity and boundary tension. The UTL can flexibly change focal lengths between positive and negative lenses when the device thickness is merely 2.15 mm. The proposed lens has the advantages of small volume, light weight, simple fabrication, and independence from external force during zooming. This research makes up for the drawback that traditional solid and liquid lenses cannot further reduce their thicknesses. The proposed UTL provides a new lens form and fabrication method, and can be used to replace solid and liquid lenses for designing miniature zoom optical systems.
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Choi SSS, Mandelis A. Review of the state of the art in cardiovascular endoscopy imaging of atherosclerosis using photoacoustic techniques with pulsed and continuous-wave optical excitations. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-15. [PMID: 31414585 PMCID: PMC6983488 DOI: 10.1117/1.jbo.24.8.080902] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/22/2019] [Indexed: 05/15/2023]
Abstract
Intravascular photoacoustics (IV-PA) is an emerging atherosclerosis imaging modality that provides chemical-specific optical information of arterial walls with acoustic depth penetration and resolution. As lipid composition of atherosclerotic plaques is considered to be one of the primary indicators for plaque vulnerability, many IV-PA applications are calibrated so as to target plaque necrotic cores. Based on the mode of optical excitation and the corresponding signal processing technique, IV-PA is categorized into two different modalities. The pulse-based IV-PA has been the universal IV-PA imaging mode with its high peak power and straightforward time-domain signal processing technique. As an alternative, the low power continuous-wave (CW)-based IV-PA has been under intense development as a radar-like frequency-domain signal processing modality. The two state-of-the-art types of IV-PA are reviewed in terms of their physics and imaging capabilities, with major emphasis on frequency-swept CW-based IV-PA that has been recently introduced in the field.
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Affiliation(s)
- Sung Soo Sean Choi
- University of Toronto, Center for Advanced Diffusion-Wave and Photoacoustic Technologies, Department of Mechanical and Industrial Engineering, Toronto, Ontario, Canada
| | - Andreas Mandelis
- University of Toronto, Center for Advanced Diffusion-Wave and Photoacoustic Technologies, Department of Mechanical and Industrial Engineering, Toronto, Ontario, Canada
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Zhang Y, Cao Y, Cheng JX. High-resolution photoacoustic endoscope through beam self-cleaning in a graded index fiber. OPTICS LETTERS 2019; 44:3841-3844. [PMID: 31368982 DOI: 10.1364/ol.44.003841] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Intravascular photoacoustic imaging can potentially improve the identification of lipid-laden atherosclerotic plaque. Most intravascular photoacoustic endoscopes use multimode fibers, which do not allow tight focusing of photons. Recent experiments on pulse propagation in multimode graded-index fibers have shown a nonlinear improvement in beam quality. Here, we harness this nonlinear phenomenon for fiber-delivery of nanosecond laser pulses. We built a photoacoustic catheter 1.4 mm outer diameter, offering a lateral resolution as fine as 30 μm within a depth range of 2.5 mm. Such resolution is one order of magnitude better than current multimode fiber-based intravascular photoacoustic catheters. At the same time, the delivered pulse energy can reach as high as 20 μJ, which is two orders of magnitude higher than that of an optical resolution photoacoustic endoscope built with a single mode fiber. These improvements are expected to promote the biomedical application of photoacoustic endoscopes which require both high resolution and high pulse energy.
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Jin X, Wang X, Xiong K, Yang S. High-resolution and extended-depth-of-field photoacoustic endomicroscopy by scanning-domain synthesis of optical beams. OPTICS EXPRESS 2019; 27:19369-19381. [PMID: 31503697 DOI: 10.1364/oe.27.019369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 06/10/2019] [Indexed: 06/10/2023]
Abstract
Photoacoustic endomicroscopy (PAEM) is capable of imaging fine structures in digestive tract. However, conventional PAEM employs a tightly focused laser beam to irradiate the object, which results in a limited depth-of-field (DOF). Here, we propose a scanning-domain synthesis of optical beams (SDSOB) to optimize both transverse resolution and the DOF by synthetic effective focused beams in scanning domain for the PAEM. By utilizing the SDSOB technique, multiple defocused and scattered beams are refocused to synthesize virtual focuses covering a large range of depth. A transverse point spread function that is 5.7-time sharper, and a transverse spatial bandwidth that is 8.5-time broader than those of the conventional PAEM were simulatively obtained through SDSOB-PAEM at the defocus distance of 2.4 mm. We validated the transverse resolution improvement at both in- and out-focus positions via phantom experiments of carbon fibers. In addition, in vivo rabbit experiments were conducted to acquire vascular images over radial depth range of 900 µm. And further morphological analysis revealed that the SDSOB images were acquired with abundant vascular branches and nodes, large total-length and small average-length of blood vessels, which indicated that the SDSOB-PAEM achieved high-resolution imaging in distinct rectal layers. All these results suggest that the SDSOB-PAEM possesses high transverse resolution and extended DOF, which demonstrates the SDSOB-PAEM can provide more accurate information for clinical assessment.
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Zheng S, Yixuan J. An image reconstruction method for endoscopic photoacoustic tomography in tissues with heterogeneous sound speed. Comput Biol Med 2019; 110:15-28. [PMID: 31103813 DOI: 10.1016/j.compbiomed.2019.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/05/2019] [Accepted: 05/08/2019] [Indexed: 11/25/2022]
Abstract
The idealized assumption of a constant speed of sound (SOS) in acoustically inhomogeneous biological tissues usually results in blurred details, acoustic distortion and artifacts in in vivo endoscopic photoacoustic tomographic (EPAT) images. In this paper, we propose an image reconstruction method to improve EPAT imaging for luminal structures with the variable SOS. In our method, an optimal SOS providing the maximal local focusing of a measuring location within the imaging region is firstly determined. The deviation in the ultrasonic propagation time caused by the variable SOS is then compensated. The grayscale images of the optical absorption distribution on the cross-sections of the luminal structures are finally reconstructed with a filtered back-projection (FBP) algorithm based on the corrected propagation time. Any prior knowledge of the SOS distribution in the imaged tissues is not required. The results of numerical simulation experiments demonstrated that the proposed method can effectively improve the image quality by reducing the misalignment of tissues, acoustic distortion and artifacts caused by the variable SOS.
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Affiliation(s)
- Sun Zheng
- Department of Electronic and Communication Engineering, North China Electric Power University, Baoding, 071003, China.
| | - Jia Yixuan
- Department of Electronic and Communication Engineering, North China Electric Power University, Baoding, 071003, China
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Periyasamy V, Das N, Sharma A, Pramanik M. 1064 nm acoustic resolution photoacoustic microscopy. JOURNAL OF BIOPHOTONICS 2019; 12:e201800357. [PMID: 30511496 DOI: 10.1002/jbio.201800357] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/22/2018] [Accepted: 11/30/2018] [Indexed: 05/03/2023]
Abstract
Photoacoustic imaging is a noninvasive imaging technique having the advantages of high-optical contrast and good acoustic resolution at improved imaging depths. Light transport in biological tissues is mainly characterized by strong optical scattering and absorption. Photoacoustic microscopy is capable of achieving high-resolution images at greater depth compared to conventional optical microscopy methods. In this work, we have developed a high-resolution, acoustic resolution photoacoustic microscopy (AR-PAM) system in the near infra-red (NIR) window II (NIR-II, eg, 1064 nm) for deep tissue imaging. Higher imaging depth is achieved as the tissue scattering at 1064 nm is lesser compared to visible or near infrared window-I (NIR-I). Our developed system can provide a lateral resolution of 130 μm, axial resolution of 57 μm, and image up to 11 mm deep in biological tissues. This 1064-AR-PAM system was used for imaging sentinel lymph node and the lymph vessel in rat. Urinary bladder of rat filled with black ink was also imaged to validate the feasibility of the developed system to study deeply seated organs.
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Affiliation(s)
- Vijitha Periyasamy
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
| | - Nandan Das
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
| | - Arunima Sharma
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
| | - Manojit Pramanik
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
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Wang L, Lei P, Wen X, Zhang P, Yang S. Tapered fiber-based intravascular photoacoustic endoscopy for high-resolution and deep-penetration imaging of lipid-rich plaque. OPTICS EXPRESS 2019; 27:12832-12840. [PMID: 31052818 DOI: 10.1364/oe.27.012832] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
High-resolution intravascular photoacoustic (IVPA) imaging can potentially improve the identification of atherosclerosis plaque. However, the absorption of water and the low coupled laser energy resulted in insufficient excitation energy provided by the single-mode fiber-based IVPA endoscope to achieve high-resolution and deep-penetration plaque imaging. In this paper, we developed a 1 mm diameter IVPA endoscope assembled with a Ø25-Ø9 μm tapered fiber. Owing to high coupling efficiency and the small output facula of tapered fiber, the IVPA endoscope has an optimal lateral resolution of 18 μm and a large imaging-depth covering from the intima to the peri-adventitial adipose, as confirmed by imaging results respectively. Furthermore, IVPA imaging in the blood has confirmed that the tapered fiber-based endoscope can display the distribution and the relative concentration of lipid in ex vivo plaque precisely. By the obtained histology-like images, IVPA imaging shows great potential for accurately imaging atherosclerosis plaque.
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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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Hu Y, Chen Z, Xiang L, Xing D. Extended depth-of-field all-optical photoacoustic microscopy with a dual non-diffracting Bessel beam. OPTICS LETTERS 2019; 44:1634-1637. [PMID: 30933109 DOI: 10.1364/ol.44.001634] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
All-optical photoacoustic microscopy (AOPAM) facilitates high-sensitivity, wide-bandwidth, volumetric imaging without coupling media. However, the rapid divergence of the Gaussian beam restricts the stability and depth-of-field in typical Gaussian AOPAM (G-AOPAM). Here we report an extended depth-of-field AOPAM using a dual non-diffracting Bessel beam (B-AOPAM). Benefiting from the designing, the B-AOPAM has the unique advantages of increasing depth resolving ability and improving photoacoustic detection sensitivity. The proposed scheme shows optimal lateral resolution of 2.4 μm and a long depth-of-focus of 635 μm, which is 10-fold larger than that of the G-AOPAM. The scattering phantoms and in vivo animal experiments demonstrated the imaging feasibility and capability of the B-AOPAM, which can provide noncontact, high spatial resolution imaging of non-flat tissue and contribute to future clinical applications.
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