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1
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He Y, Liu X, Zhang J, Peng C. A Backing-Layer-Shared Miniature Dual-Frequency Ultrasound Probe for Intravascular Ultrasound Imaging: In Vitro and Ex Vivo Validations. BIOSENSORS 2023; 13:971. [PMID: 37998146 PMCID: PMC10669229 DOI: 10.3390/bios13110971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/29/2023] [Accepted: 10/31/2023] [Indexed: 11/25/2023]
Abstract
Intravascular ultrasound (IVUS) imaging has been extensively utilized to visualize atherosclerotic coronary artery diseases and to guide coronary interventions. To receive ultrasound signals within the vessel wall safely and effectively, miniaturized ultrasound transducers that meet the strict size constraints and have a simple manufacturing procedure are highly demanded. In this work, the first known IVUS probe that employs a backing-layer-shared dual-frequency structure and a single coaxial cable is introduced, featuring a small thickness and easy interconnection procedure. The dual-frequency transducer is designed to have center frequencies of 30 MHz and 80 MHz, and both have an aperture size of 0.5 mm × 0.5 mm. The total thickness of the dual-frequency transducer is less than 700 µm. In vitro phantom imaging and ex vivo porcine coronary artery imaging experiments are conducted. The low-frequency transducer achieves spatial resolutions of 40 µm axially and 321 µm laterally, while the high-frequency transducer exhibits axial and lateral resolutions of 17 µm and 247 µm, respectively. A bandpass filter is utilized to separate the ultrasound images. Combining in vitro phantom imaging analysis with ex vivo imaging validation, a comprehensive demonstration of the promising application of the proposed miniature ultrasound probe is established.
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Affiliation(s)
- Yashuo He
- School of Biomedical Engineering, ShanghaiTech University, Shanghai 201210, China
| | - Xi Liu
- School of Biomedical Engineering, ShanghaiTech University, Shanghai 201210, China
| | - Jiayi Zhang
- School of Biomedical Engineering, ShanghaiTech University, Shanghai 201210, China
| | - Chang Peng
- School of Biomedical Engineering, ShanghaiTech University, Shanghai 201210, China
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2
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Hu H, Ma Y, Gao X, Song D, Li M, Huang H, Qian X, Wu R, Shi K, Ding H, Lin M, Chen X, Zhao W, Qi B, Zhou S, Chen R, Gu Y, Chen Y, Lei Y, Wang C, Wang C, Tong Y, Cui H, Abdal A, Zhu Y, Tian X, Chen Z, Lu C, Yang X, Mu J, Lou Z, Eghtedari M, Zhou Q, Oberai A, Xu S. Stretchable ultrasonic arrays for the three-dimensional mapping of the modulus of deep tissue. Nat Biomed Eng 2023; 7:1321-1334. [PMID: 37127710 DOI: 10.1038/s41551-023-01038-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/05/2023] [Indexed: 05/03/2023]
Abstract
Serial assessment of the biomechanical properties of tissues can be used to aid the early detection and management of pathophysiological conditions, to track the evolution of lesions and to evaluate the progress of rehabilitation. However, current methods are invasive, can be used only for short-term measurements, or have insufficient penetration depth or spatial resolution. Here we describe a stretchable ultrasonic array for performing serial non-invasive elastographic measurements of tissues up to 4 cm beneath the skin at a spatial resolution of 0.5 mm. The array conforms to human skin and acoustically couples with it, allowing for accurate elastographic imaging, which we validated via magnetic resonance elastography. We used the device to map three-dimensional distributions of the Young's modulus of tissues ex vivo, to detect microstructural damage in the muscles of volunteers before the onset of soreness and to monitor the dynamic recovery process of muscle injuries during physiotherapies. The technology may facilitate the diagnosis and treatment of diseases affecting tissue biomechanics.
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Affiliation(s)
- Hongjie Hu
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Yuxiang Ma
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Xiaoxiang Gao
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Dawei Song
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Mohan Li
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Hao Huang
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Xuejun Qian
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Ray Wu
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Keren Shi
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Hong Ding
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Muyang Lin
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Xiangjun Chen
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Wenbo Zhao
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Baiyan Qi
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Sai Zhou
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Ruimin Chen
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Yue Gu
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Yimu Chen
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Yusheng Lei
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Chonghe Wang
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Chunfeng Wang
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Yitian Tong
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Haotian Cui
- Department of Computer Science, University of Toronto, Toronto, Ontario, Canada
| | - Abdulhameed Abdal
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, USA
| | - Yangzhi Zhu
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Xinyu Tian
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Zhaoxin Chen
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Chengchangfeng Lu
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Xinyi Yang
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Jing Mu
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Zhiyuan Lou
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Mohammad Eghtedari
- Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Qifa Zhou
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Assad Oberai
- Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Sheng Xu
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA.
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA.
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA.
- Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA.
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3
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Lewis-Thompson I, Zhang EZ, Beard PC, Desjardins AE, Colchester RJ. All-optical ultrasound catheter for rapid B-mode oesophageal imaging. BIOMEDICAL OPTICS EXPRESS 2023; 14:4052-4064. [PMID: 37799692 PMCID: PMC10549740 DOI: 10.1364/boe.494878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/30/2023] [Accepted: 06/30/2023] [Indexed: 10/07/2023]
Abstract
All-optical ultrasound (OpUS) is an imaging paradigm that uses light to both generate and receive ultrasound, and has progressed from benchtop to in vivo studies in recent years, demonstrating promise for minimally invasive surgical applications. In this work, we present a rapid pullback imaging catheter for side-viewing B-mode ultrasound imaging within the upper gastrointestinal tract. The device comprised an ultrasound transmitter configured to generate ultrasound laterally from the catheter and a plano-concave microresonator for ultrasound reception. This imaging probe was capable of generating ultrasound pressures in excess of 1 MPa with corresponding -6 dB bandwidths > 20 MHz. This enabled imaging resolutions as low as 45 µm and 120 µm in the axial and lateral extent respectively, with a corresponding signal-to-noise ratio (SNR) of 42 dB. To demonstrate the potential of the device for clinical imaging, an ex vivo swine oesophagus was imaged using the working channel of a mock endoscope for device delivery. The full thickness of the oesophagus was resolved and several tissue layers were present in the resulting ultrasound images. This work demonstrates the promise for OpUS to provide rapid diagnostics and guidance alongside conventional endoscopy.
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Affiliation(s)
- India Lewis-Thompson
- Department of Medical Physics and
Biomedical Engineering,
University College London, Gower Street, London, WC1E 6BT, UK
- Wellcome/EPSRC Centre for Interventional
and Surgical Sciences,
University College London, Charles Bell House, Foley Street, London, W1W 7TY, UK
| | - Edward Z. Zhang
- Department of Medical Physics and
Biomedical Engineering,
University College London, Gower Street, London, WC1E 6BT, UK
| | - Paul C. Beard
- Department of Medical Physics and
Biomedical Engineering,
University College London, Gower Street, London, WC1E 6BT, UK
- Wellcome/EPSRC Centre for Interventional
and Surgical Sciences,
University College London, Charles Bell House, Foley Street, London, W1W 7TY, UK
| | - Adrien E. Desjardins
- Department of Medical Physics and
Biomedical Engineering,
University College London, Gower Street, London, WC1E 6BT, UK
- Wellcome/EPSRC Centre for Interventional
and Surgical Sciences,
University College London, Charles Bell House, Foley Street, London, W1W 7TY, UK
| | - Richard J. Colchester
- Department of Medical Physics and
Biomedical Engineering,
University College London, Gower Street, London, WC1E 6BT, UK
- Wellcome/EPSRC Centre for Interventional
and Surgical Sciences,
University College London, Charles Bell House, Foley Street, London, W1W 7TY, UK
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4
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Hu H, Huang H, Li M, Gao X, Yin L, Qi R, Wu RS, Chen X, Ma Y, Shi K, Li C, Maus TM, Huang B, Lu C, Lin M, Zhou S, Lou Z, Gu Y, Chen Y, Lei Y, Wang X, Wang R, Yue W, Yang X, Bian Y, Mu J, Park G, Xiang S, Cai S, Corey PW, Wang J, Xu S. A wearable cardiac ultrasound imager. Nature 2023; 613:667-675. [PMID: 36697864 PMCID: PMC9876798 DOI: 10.1038/s41586-022-05498-z] [Citation(s) in RCA: 104] [Impact Index Per Article: 104.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 10/31/2022] [Indexed: 01/26/2023]
Abstract
Continuous imaging of cardiac functions is highly desirable for the assessment of long-term cardiovascular health, detection of acute cardiac dysfunction and clinical management of critically ill or surgical patients1-4. However, conventional non-invasive approaches to image the cardiac function cannot provide continuous measurements owing to device bulkiness5-11, and existing wearable cardiac devices can only capture signals on the skin12-16. Here we report a wearable ultrasonic device for continuous, real-time and direct cardiac function assessment. We introduce innovations in device design and material fabrication that improve the mechanical coupling between the device and human skin, allowing the left ventricle to be examined from different views during motion. We also develop a deep learning model that automatically extracts the left ventricular volume from the continuous image recording, yielding waveforms of key cardiac performance indices such as stroke volume, cardiac output and ejection fraction. This technology enables dynamic wearable monitoring of cardiac performance with substantially improved accuracy in various environments.
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Affiliation(s)
- Hongjie Hu
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Hao Huang
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Mohan Li
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Xiaoxiang Gao
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Lu Yin
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Ruixiang Qi
- Department of Computer Science and Engineering, University of California San Diego, La Jolla, CA, USA
| | - Ray S Wu
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Xiangjun Chen
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Yuxiang Ma
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Keren Shi
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
- Materials Science and Engineering Program, University of California, Riverside, CA, USA
| | - Chenghai Li
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, USA
| | - Timothy M Maus
- Department of Anesthesiology, University of California, San Diego Health Sulpizio Cardiovascular Center, La Jolla, CA, USA
| | - Brady Huang
- Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Chengchangfeng Lu
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Muyang Lin
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Sai Zhou
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Zhiyuan Lou
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Yue Gu
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Yimu Chen
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Yusheng Lei
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Xinyu Wang
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Ruotao Wang
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Wentong Yue
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Xinyi Yang
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Yizhou Bian
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Jing Mu
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Geonho Park
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
| | - Shu Xiang
- Softsonics, Inc., San Diego, CA, USA
| | - Shengqiang Cai
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, USA
| | - Paul W Corey
- Department of Anesthesiology, Sharp Memorial Hospital, San Diego, CA, USA
| | - Joseph Wang
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Sheng Xu
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA.
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA.
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA.
- Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA.
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5
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Kim H, Yoo J, Heo D, Seo YS, Lim HG, Kim HH. High-Attenuation Backing Layer for Miniaturized Ultrasound Imaging Transducer. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:1960-1969. [PMID: 35377844 DOI: 10.1109/tuffc.2022.3164451] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Current miniaturized ultrasound transducers suffer from insufficient attenuation from the backing layer due to their limited thickness. The thickness of the backing layer is one of the critical factors determining the device size and transducer performance for miniaturized transducers inserted and operated in a limited space. Glass bubbles, polyamide resin, and tungsten powder are combined to form a new highly attenuative backing material. It has high attenuation (>160 dB/cm at 5 MHz), which is five times greater than silver-based conductive epoxy commonly used for high-frequency ultrasound transducers, appropriate acoustic impedance (4.6 MRayl), and acceptable damping capability. An intravascular ultrasound (IVUS) transducer constructed with the 170 [Formula: see text] of the proposed backing layer demonstrated that the amplitude of the signal returned from the backing layer was 1.8 times smaller, with ring-down attenuated by 6 dB. Wire-phantom imaging revealed that the axial resolution was 30% better with the suggested backing than silver-based conductive epoxy backing. Because of its excellent attenuation capability even at a limited thickness, simple manufacturing process, and easy customization capability, the suggested highly attenuative backing layer may be used for miniaturized ultrasound transducers.
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6
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Nguyen TP, Choi J, Nguyen VT, Mondal S, Bui NT, Vu DD, Park S, Oh J. Design and Micro-Fabrication of Focused High-Frequency Needle Transducers for Medical Imaging. SENSORS (BASEL, SWITZERLAND) 2022; 22:3763. [PMID: 35632172 PMCID: PMC9143298 DOI: 10.3390/s22103763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/09/2022] [Accepted: 05/13/2022] [Indexed: 01/25/2023]
Abstract
In this study, we report an advanced fabrication technique to develop a miniature focused needle transducer. Two different types of high-frequency (100 MHz) transducers were fabricated using the lead magnesium niobate-lead titanate (PMN-0.3PT) and lithium niobate (LiNbO3) single crystals. In order to enhance the transducer's performance, a unique mass-spring matching layer technique was adopted, in which gold and parylene play the roles of the mass layer and spring layer, respectively. The PMN-0.3PT transducer had a 103 MHz center frequency with a -6 dB bandwidth of 52%, and a signal-to-noise ratio (SNR) of 42 dB. The center frequency, -6 dB bandwidth, and SNR of the LiNbO3 transducer were 105 MHz, 66%, and 44 dB, respectively. In order to compare and evaluate the transducers' performances, an ultrasonic biomicroscopy (UBM) imaging on the fish eye was performed. The results showed that the LiNbO3 transducer had a better contrast resolution compared to the PMN-0.3PT transducer. The fabricated transducer showed an excellent performance with high-resolution corneal epithelium imaging of the experimental fish eye. These interesting findings are useful for the future biomedical implementation of the fabricated transducers in the field of high-resolution ultrasound imaging and diagnosis purpose.
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Affiliation(s)
- Thanh Phuoc Nguyen
- Department of Mechatronics, Cao Thang Technical College, Ho Chi Minh City 700000, Vietnam
| | - Jaeyeop Choi
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan 48513, Korea; (J.C.); (V.T.N.); (D.D.V.); (S.P.); (J.O.)
| | - Van Tu Nguyen
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan 48513, Korea; (J.C.); (V.T.N.); (D.D.V.); (S.P.); (J.O.)
| | - Sudip Mondal
- New-Senior Healthcare Innovation Center (BK21 Plus), Pukyong National University, Busan 48513, Korea;
| | - Ngoc Thang Bui
- Institute of Engineering, HUTECH University, Ho Chi Minh City 700000, Vietnam;
| | - Dinh Dat Vu
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan 48513, Korea; (J.C.); (V.T.N.); (D.D.V.); (S.P.); (J.O.)
| | - Sumin Park
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan 48513, Korea; (J.C.); (V.T.N.); (D.D.V.); (S.P.); (J.O.)
| | - Junghwan Oh
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan 48513, Korea; (J.C.); (V.T.N.); (D.D.V.); (S.P.); (J.O.)
- New-Senior Healthcare Innovation Center (BK21 Plus), Pukyong National University, Busan 48513, Korea;
- Ohlabs Corporation, Busan 48513, Korea
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7
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Liang S, Su M, Liu B, Liu R, Zheng H, Qiu W, Zhang Z. Evaluation of Blood Induced Influence for High-Definition Intravascular Ultrasound (HD-IVUS). IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:98-105. [PMID: 34437062 DOI: 10.1109/tuffc.2021.3108163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
High-definition intravascular ultrasound (HD-IVUS) utilizing more than 80 MHz frequency to assess atherosclerotic plaque, can theoretically achieve an axial resolution of less than [Formula: see text]. However, the blood is a high-attenuation source at high frequency, which would affect the imaging quality. There has been no research evaluating the blood-induced influence on HD-IVUS imaging. And whether a temporary removal of blood is needed for HD-IVUS is unknown. In this study, an ultrahigh-frequency (100 MHz) ultrasound transducer was developed to evaluate the blood-induced attenuation for HD-IVUS imaging. A series of tungsten-wire phantom images in saline and blood at varying hematocrits were obtained. The images showed that blood did influence the ultrahigh-frequency imaging quality greatly. The signal-to-noise ratio (SNR) decrease by 71.7% in porcine whole blood compared to that in saline at the same depth of 2.3 mm. Moreover, the potential flushing schemes for HD-IVUS were studied in varying hematocrits. Three flushing agents commonly used in intravascular optical coherence tomography (IV-OCT) were investigated, including iohexol, mannitol, and dextran 5% and saline as the control group. The attenuation of blood in varying hematocrits/flushing agents was measured from 90 to 110 MHz. The result indicated dextran 5% was a suitable flushing agent for HD-IVUS due to its less signal attenuation compared to others.
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8
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Feuillard G, Hue LPTH, Saadaoui N, Nguyen VT, Lethiecq M, Saillant JF. Symmetric Reflector Ultrasonic Transducer Modeling and Characterization: Role of the Matching Layer on Electroacoustic Performance. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:3608-3615. [PMID: 34319873 DOI: 10.1109/tuffc.2021.3101124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Symmetric reflector ultrasonic transducers (SRUTs) are a new type of ultrasonic transducer that take advantage of the ultrasonic wave emitted on the rear face of the active element. In this work, the electroacoustic modeling and characterization of such a structure is reported. Using the well-known Krimholtz, Leedom, et Matthaei (KLM) model, the electroacoustic response of a SRUT based on a piezoelectric ceramic with one matching layer is calculated. Simulations show that the optimal acoustic impedance of the matching layer should be lower than for conventional transducers, leading to a relative bandwidth of approximately 50%. The characterization of such a transducer based on a piezoceramic plate has been carried out. Bandwidth and sensitivity are reported. They are found to be close to the simulation results and demonstrate that these new types of transducers need to be designed according to new rules compared to conventional ones.
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9
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Kariminejad M, Tormey D, Huq S, Morrison J, McAfee M. Ultrasound Sensors for Process Monitoring in Injection Moulding. SENSORS (BASEL, SWITZERLAND) 2021; 21:5193. [PMID: 34372430 PMCID: PMC8347947 DOI: 10.3390/s21155193] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/22/2021] [Accepted: 07/28/2021] [Indexed: 11/17/2022]
Abstract
Injection moulding is an extremely important industrial process, being one of the most commonly-used plastic formation techniques. However, the industry faces many current challenges associated with demands for greater product customisation, higher precision and, most urgently, a shift towards more sustainable materials and processing. Accurate real-time sensing of the material and part properties during processing is key to achieving rapid process optimisation and set-up, reducing down-times, and reducing waste material and energy in the production of defective products. While most commercial processes rely on point measurements of pressure and temperature, ultrasound transducers represent a non-invasive and non-destructive source of rich information on the mould, the cavity and the polymer melt, and its morphology, which affect critical quality parameters such as shrinkage and warpage. In this paper the relationship between polymer properties and the propagation of ultrasonic waves is described and the application of ultrasound measurements in injection moulding is evaluated. The principles and operation of both conventional and high temperature ultrasound transducers (HTUTs) are reviewed together with their impact on improving the efficiency of the injection moulding process. The benefits and challenges associated with the recent development of sol-gel methods for HTUT fabrication are described together with a synopsis of further research and development needed to ensure a greater industrial uptake of ultrasonic sensing in injection moulding.
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Affiliation(s)
- Mandana Kariminejad
- Centre for Precision Engineering, Materials and Manufacturing (PEM Centre), Institute of Technology Sligo, Ash Lane, F91 YW50 Sligo, Ireland;
- Centre for Mathematical Modelling and Intelligent Systems for Health and Environment (MISHE), Institute of Technology Sligo, Ash Lane, F91 YW50 Sligo, Ireland
| | - David Tormey
- Centre for Precision Engineering, Materials and Manufacturing (PEM Centre), Institute of Technology Sligo, Ash Lane, F91 YW50 Sligo, Ireland;
| | - Saif Huq
- School of Computing and Digital Media, London Metropolitan University, 166-220 Holloway Rd, London N7 8DB, UK;
| | - Jim Morrison
- Department of Electronics and Mechanical Engineering, Letterkenny Institute of Technology, Port Rd, Gortlee, Letterkenny, F92 FC93 Donegal, Ireland;
| | - Marion McAfee
- Centre for Precision Engineering, Materials and Manufacturing (PEM Centre), Institute of Technology Sligo, Ash Lane, F91 YW50 Sligo, Ireland;
- Centre for Mathematical Modelling and Intelligent Systems for Health and Environment (MISHE), Institute of Technology Sligo, Ash Lane, F91 YW50 Sligo, Ireland
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10
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Sung JH, Chang JH. Mechanically Rotating Intravascular Ultrasound (IVUS) Transducer: A Review. SENSORS (BASEL, SWITZERLAND) 2021; 21:3907. [PMID: 34198822 PMCID: PMC8201242 DOI: 10.3390/s21113907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/31/2021] [Accepted: 06/03/2021] [Indexed: 12/30/2022]
Abstract
Intravascular ultrasound (IVUS) is a valuable imaging modality for the diagnosis of atherosclerosis. It provides useful clinical information, such as lumen size, vessel wall thickness, and plaque composition, by providing a cross-sectional vascular image. For several decades, IVUS has made remarkable progress in improving the accuracy of diagnosing cardiovascular disease that remains the leading cause of death globally. As the quality of IVUS images mainly depends on the performance of the IVUS transducer, various IVUS transducers have been developed. Therefore, in this review, recently developed mechanically rotating IVUS transducers, especially ones exploiting piezoelectric ceramics or single crystals, are discussed. In addition, this review addresses the history and technical challenges in the development of IVUS transducers and the prospects of next-generation IVUS transducers.
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Affiliation(s)
| | - Jin-Ho Chang
- Department of Information and Communication Engineering, Deagu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea;
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Peng C, Wu H, Kim S, Dai X, Jiang X. Recent Advances in Transducers for Intravascular Ultrasound (IVUS) Imaging. SENSORS (BASEL, SWITZERLAND) 2021; 21:3540. [PMID: 34069613 PMCID: PMC8160965 DOI: 10.3390/s21103540] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/11/2021] [Accepted: 05/17/2021] [Indexed: 12/16/2022]
Abstract
As a well-known medical imaging methodology, intravascular ultrasound (IVUS) imaging plays a critical role in diagnosis, treatment guidance and post-treatment assessment of coronary artery diseases. By cannulating a miniature ultrasound transducer mounted catheter into an artery, the vessel lumen opening, vessel wall morphology and other associated blood and vessel properties can be precisely assessed in IVUS imaging. Ultrasound transducer, as the key component of an IVUS system, is critical in determining the IVUS imaging performance. In recent years, a wide range of achievements in ultrasound transducers have been reported for IVUS imaging applications. Herein, a comprehensive review is given on recent advances in ultrasound transducers for IVUS imaging. Firstly, a fundamental understanding of IVUS imaging principle, evaluation parameters and IVUS catheter are summarized. Secondly, three different types of ultrasound transducers (piezoelectric ultrasound transducer, piezoelectric micromachined ultrasound transducer and capacitive micromachined ultrasound transducer) for IVUS imaging are presented. Particularly, the recent advances in piezoelectric ultrasound transducer for IVUS imaging are extensively examined according to their different working mechanisms, configurations and materials adopted. Thirdly, IVUS-based multimodality intravascular imaging of atherosclerotic plaque is discussed. Finally, summary and perspectives on the future studies are highlighted for IVUS imaging applications.
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Affiliation(s)
- Chang Peng
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA; (C.P.); (H.W.)
| | - Huaiyu Wu
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA; (C.P.); (H.W.)
| | | | - Xuming Dai
- Department of Cardiology, New York-Presbyterian Queens Hospital, Flushing, NY 11355, USA;
| | - Xiaoning Jiang
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA; (C.P.); (H.W.)
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12
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Lim HG, Kim HH, Yoon C. Synthetic Aperture Imaging Using High-Frequency Convex Array for Ophthalmic Ultrasound Applications. SENSORS 2021; 21:s21072275. [PMID: 33805048 PMCID: PMC8036709 DOI: 10.3390/s21072275] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/21/2021] [Accepted: 03/22/2021] [Indexed: 11/16/2022]
Abstract
High-frequency ultrasound (HFUS) imaging has emerged as an essential tool for pre-clinical studies and clinical applications such as ophthalmic and dermatologic imaging. HFUS imaging systems based on array transducers capable of dynamic receive focusing have considerably improved the image quality in terms of spatial resolution and signal-to-noise ratio (SNR) compared to those by the single-element transducer-based one. However, the array system still suffers from low spatial resolution and SNR in out-of-focus regions, resulting in a blurred image and a limited penetration depth. In this paper, we present synthetic aperture imaging with a virtual source (SA-VS) for an ophthalmic application using a high-frequency convex array transducer. The performances of the SA-VS were evaluated with phantom and ex vivo experiments in comparison with the conventional dynamic receive focusing method. Pre-beamformed radio-frequency (RF) data from phantoms and excised bovine eye were acquired using a custom-built 64-channel imaging system. In the phantom experiments, the SA-VS method showed improved lateral resolution (>10%) and sidelobe level (>4.4 dB) compared to those by the conventional method. The SNR was also improved, resulting in an increased penetration depth: 16 mm and 23 mm for the conventional and SA-VS methods, respectively. Ex vivo images with the SA-VS showed improved image quality at the entire depth and visualized structures that were obscured by noise in conventional imaging.
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Affiliation(s)
- Hae Gyun Lim
- Department of Biomedical Engineering, Pukyong National University, Busan 48513, Korea;
| | - Hyung Ham Kim
- Department of Convergence IT Engineering, Pohang University of Science and Technology, Pohang 37673, Korea
- Correspondence: (H.H.K.); or (C.Y.)
| | - Changhan Yoon
- Department of Biomedical Engineering, Inje University, Gimhae 50834, Korea
- Department of Nanoscience and Engineering, Inje University, Gimhae 50834, Korea
- Correspondence: (H.H.K.); or (C.Y.)
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Sung JH, Jeong EY, Jeong JS. Intravascular Ultrasound Transducer by Using Polarization Inversion Technique for Tissue Harmonic Imaging: Modeling and Experiments. IEEE Trans Biomed Eng 2020; 67:3380-3391. [PMID: 32286955 DOI: 10.1109/tbme.2020.2986284] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Intravascular ultrasound (IVUS) tissue harmonic imaging (THI) is a useful vessel imaging technique that can provide deep penetration depth as well as high spatial and contrast resolution. Typically, a high-frequency IVUS transducer for THI requires a broad bandwidth or dual-frequency bandwidth. However, it is very difficult to make an IVUS transducer with a frequency bandwidth covering from the fundamental frequency to the second harmonic or a dual-peak at the desired frequency. To solve this problem, in this study, we applied the polarization inversion technique (PIT) to the IVUS transducer for THI. The PIT makes it relatively easy to design IVUS transducers with suitable frequency characteristics for THI depending on the inversion ratio of the piezoelectric layer and specifications of the passive materials. In this study, two types of IVUS transducers based on the PIT were developed for THI. One is a front-side inversion layer (FSIL) transducer with a broad bandwidth, and the other is a back-side inversion layer (BSIL) transducer with a dual-frequency bandwidth. These transducers were designed using finite element analysis (FEA)-based simulation, and the prototype transducers were fabricated. Subsequently, the performance was evaluated by not only electrical impedance and pulse-echo response tests but also B-mode imaging tests with a 25 μm tungsten wire and tissue-mimicking gelatin phantoms. The FEA simulation and experimental results show that the proposed scheme can successfully implement the tissue harmonic IVUS image, and thus it can be one of the promising techniques for developing IVUS transducers for THI.
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Munding CE, Chérin E, Alves N, Goertz DE, Courtney BK, Foster FS. 30/80 MHz Bidirectional Dual-Frequency IVUS Feasibility Evaluated In Vivo and for Stent Imaging. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:2104-2112. [PMID: 32473846 DOI: 10.1016/j.ultrasmedbio.2020.03.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 03/15/2020] [Accepted: 03/29/2020] [Indexed: 06/11/2023]
Abstract
Although intravascular ultrasound (IVUS) is an important tool in guiding complex coronary interventions, the resolution of existing commercial IVUS devices is considerably poorer than that of optical coherence tomography. Dual-frequency IVUS (DF IVUS), incorporating a second, higher frequency transducer, has been proposed as a possible method of overcoming this limitation. Although preliminary studies have shown that DF IVUS can produce complementary images, including large-scale morphology and high detail of superficial features, it has not yet been determined that this approach would be feasible in a more clinically relevant environment. The purpose of this study was to demonstrate the first in vivo use of a 30/80 MHz DF IVUS catheter in visualizing coronary vessels in a porcine model. In addition, two commercially available stents were studied in vitro and in vivo. Clear subjective improvement of visualization of superficial structures is demonstrated, and sufficient dynamic range is achieved to image through both the catheter sheath and blood in vivo.
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Affiliation(s)
- Chelsea E Munding
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
| | | | | | - David E Goertz
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Sunnybrook Research Institute, Toronto, ON, Canada
| | - Brian K Courtney
- Sunnybrook Research Institute, Toronto, ON, Canada; Schulich Heart Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; Department of Medicine, University of Toronto, Toronto, ON, Canada; Conavi Medical Inc., Toronto, ON, Canada
| | - F Stuart Foster
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Sunnybrook Research Institute, Toronto, ON, Canada
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Ma X, Cao W. Single-Crystal High-Frequency Intravascular Ultrasound Transducer With 40- μ m Axial Resolution. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2020; 67:810-816. [PMID: 31794395 DOI: 10.1109/tuffc.2019.2956603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Intravascular ultrasound (IVUS) is one of the most useful tools available today to assist intravascular stenting procedures. Having higher resolution is very important for helping doctors to evaluate the nature of atherosclerotic plaques. The current commercial IVUS systems have a spatial resolution of 70- [Formula: see text] in the axial direction and 200- [Formula: see text] in the lateral direction, which are insufficient for accurate diagnosis. We report here a three-matching-layer IVUS transducer design using a 0.72Pb(Mg1/3Nb2/3O3 - 0.28PbTiO3 single crystal, which can improve the axial resolution to [Formula: see text] without sacrificing the penetration depth. Wire phantom imaging and in vitro porcine coronary artery imaging show noticeably better axial resolution and similar penetration depth compared with a commercial IVUS transducer.
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Li M, Shao W, Jiang X, Feng Z. Deconvolution in Intravascular Ultrasound to Improve Lateral Resolution. ULTRASONIC IMAGING 2019; 41:191-205. [PMID: 30990118 DOI: 10.1177/0161734619838456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Intravascular ultrasound (IVUS) is an important diagnostic method for coronary disease. The lateral and axial resolutions of IVUS systems under study are typically ~120 and ~30 µm, respectively. The lateral resolution has a lower quality than the axial one and is restricted by the aperture size of transducers. In addition, this resolution is difficult to further improve physically. However, IVUS is inherently suitable for lateral deconvolution because of its circular imaging area. In this paper, magnitude-based deconvolution was demonstrated to be feasible in IVUS imaging to improve the lateral resolution. The deconvolution process was first simulated to determine the highest feasible resolution. Next, the method was applied to a real system to validate the feasibility. The lateral resolution was improved significantly, that is, 2°-separated targets could be discerned using a transducer with 4.2° -6 dB lateral resolution.
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Affiliation(s)
- Mingxia Li
- 1 Department of Precision Machinery & Precision Instrumentation, University of Science and Technology of China, Hefei, China
| | - Weiwei Shao
- 2 Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, China
| | - Xiaoning Jiang
- 3 Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, USA
| | - Zhihua Feng
- 1 Department of Precision Machinery & Precision Instrumentation, University of Science and Technology of China, Hefei, China
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Arkan EF, Degertekin FL. Analysis and Design of High-Frequency 1-D CMUT Imaging Arrays in Noncollapsed Mode. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2019; 66:382-393. [PMID: 30571620 PMCID: PMC6415772 DOI: 10.1109/tuffc.2018.2887043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
High-frequency ultrasound imaging arrays are important for a broad range of applications, from small animal imaging to photoacoustics. Capacitive micromachined ultrasonic transducer (CMUT) arrays are particularly attractive for these applications as low noise receiver electronics can be integrated for an overall improved performance. In this paper, we present a comprehensive analysis of high-frequency CMUT arrays based on an experimentally verified CMUT array simulation tool. The results obtained on an example, a 40-MHz 1-D CMUT array for intravascular imaging, are used to obtain key design insights and tradeoffs for receive only and pulse-echo imaging. For the receiver side, thermal mechanical current noise, plane wave pressure sensitivity, and pressure noise spectrum are extracted from simulations. Using these parameters, we find that the receiver performance of CMUT arrays can be close to an ideal piston, independent of gap thickness, and applied dc bias, when coupled to low noise electronics with arrays utilizing smaller membranes performing better. For pulse-echo imaging, thermal mechanical current noise limited signal-to-noise ratio is observed to be dependent on the maximum available voltage and gap thickness. In terms of bandwidth, we find that the Bragg resonance of the array, related to the fill factor, is a significant determinant of the high frequency limit and the fluid loaded single membrane resonance determines the lower limit. Based on these results, we present design guidelines requiring only fluid loaded single membrane simulations and membrane pitch to achieve a desired pulse-echo response. We also provide a design example and discuss limitations of the approach.
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Development of High-Frequency (>60 MHz) Intravascular Ultrasound (IVUS) Transducer by Using Asymmetric Electrodes for Improved Beam Profile. SENSORS 2018; 18:s18124414. [PMID: 30551639 PMCID: PMC6308511 DOI: 10.3390/s18124414] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/07/2018] [Accepted: 12/08/2018] [Indexed: 02/01/2023]
Abstract
In most commercial single-element intravascular ultrasound (IVUS) transducers, with 20 MHz to 40 MHz center frequencies, a conductive adhesive is used to bond a micro-sized cable for the signal line to the surface of the transducer aperture (<1 mm × 1 mm size) where ultrasound beam is generated. Therefore, the vibration of the piezoelectric layer is significantly disturbed by the adhesive with the signal line, thereby causing problems, such as reduced sensitivity, shortened penetration depth, and distorted beam profile. This phenomenon becomes more serious as the center frequency of the IVUS transducer is increased, and the aperture size becomes small. Therefore, we propose a novel IVUS acoustic stack employing asymmetric electrodes with conductive and non-conductive backing blocks. The purpose of this study is to verify the extent of performance degradation caused by the adhesive with the signal line, and to demonstrate how much performance degradation can be minimized by the proposed scheme. Finite element analysis (FEA) simulation was conducted, and the results show that −3 dB, −6 dB, and −10 dB penetration depths of the conventional transducer were shortened by 20%, 25%, and 19% respectively, while those of the proposed transducer were reduced only 3%, 4%, and 0% compared with their ideal transducers which have the same effective aperture size. Besides, the proposed transducer improved the −3 dB, −6 dB, and −10 dB penetration depths by 15%, 12%, and 10% respectively, compared with the conventional transducer. We also fabricated a 60 MHz IVUS transducer by using the proposed technique, and high-resolution IVUS B-mode (brightness mode) images were obtained. Thus, the proposed scheme can be one of the potential ways to provide more uniform beam profile resulting in improving the signal to noise ratio (SNR) in IVUS image.
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Sano KH, Karasawa R, Yanagitani T. ScAlN Thick-Film Ultrasonic Transducer in 40-80 MHz. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2018; 65:2097-2102. [PMID: 30418872 DOI: 10.1109/tuffc.2018.2865791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A medical ultrasound diagnostic system and an ultrasonic microscope are generally used in the frequency range of 1-20 MHz and 100 MHz-2 GHz, respectively. Ultrasonic transducers in the frequency range of 20-100 MHz are, therefore, not well developed because of less application into ultrasonic imaging or suitable piezoelectric materials with this frequency range. Polyvinylidene difluoride (PVDF) is usually used for ultrasonic transducers in the 10-50-MHz ranges. However, their electromechanical coupling coefficient of 4% is not enough for the practical uses. In order to excite the ultrasonic wave in the 20-100 MHz range, a 125-25- -thick piezoelectric film is required when the longitudinal velocity of the material is assumed to be 5000 m/s. However, it is difficult to grow such a thick piezoelectric film without a crack being caused by the internal stress during the dry deposition technique. We achieved a stress-free film growth by employing the unique hot target sputtering technique without heating the substrate. High-efficient 81- ( .5%) and 43-MHz ( %) ultrasonic generation by using the 43- and 90- extremely thick ScAlN (Sc: 39%) films were demonstrated, respectively. We discussed the advantage of ScAlN thick-film transducers by comparing them with the conventional PVDF transducer for the water medium.
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Guo F, Wang Y, Huang Z, Qiu W, Zhang Z, Wang Z, Dong J, Yang B, Cao W. Magnesium Alloy Matching Layer for PMN-PT Single Crystal Transducer Applications. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2018; 65:1865-1872. [PMID: 30072319 DOI: 10.1109/tuffc.2018.2861394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this paper, we propose using magnesium alloy as the matching layer for the ultrasonic transducer made of 0.68 Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 (PMN-0.32PT) single crystal. The complete sets of elastic constants of AZ31B, GW83, and ZK60 magnesium alloys have been measured, which is practically a homogeneous material. The AZ31B magnesium alloy has an acoustic impedance of 10.36 MRayl, which is suitable for the development of high-performance ultrasonic transducers. A 3.5-MHz PMN-PT single crystal transducer has been designed and fabricated successfully using AZ31B magnesium alloy as the first quarter-wavelength matching layer. The -6-dB bandwidth and two-way insertion loss at the center frequency of the transducer are about 67% and 11.4 dB, respectively, much superior to the transducer fabricated using 0-3 composite matching layer. The high performance of this transducer indicates that the magnesium alloy is indeed an excellent matching layer material for ultrasonic transducer applications.
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Zhang J, Ren W, Liu Y, Wu X, Fei C, Quan Y, Zhou Q. Fabrication and Characterization of High-Frequency Ultrasound Transducers Based on Lead-Free BNT-BT Tape-Casting Thick Film. SENSORS (BASEL, SWITZERLAND) 2018; 18:E3166. [PMID: 30235869 PMCID: PMC6165567 DOI: 10.3390/s18093166] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/11/2018] [Accepted: 09/12/2018] [Indexed: 12/04/2022]
Abstract
A lead-free 0.94(Na0.5Bi0.5) TiO₃-0.06 BaTiO₃ (BNT-BT) thick film, with a thickness of 60 μm, has been fabricated using a tape-casting method. The longitudinal piezoelectric constant, clamped dielectric permittivity constant, remnant polarization and coercive field of the BNT-BT thick film were measured to be 150 pC/N, 1928, 13.6 μC/cm², and 33.6 kV/cm, respectively. The electromechanical coupling coefficient kt was calculated to be 0.55 according to the measured electrical impedance spectrum. A high-frequency plane ultrasound transducer was successfully fabricated using a BNT-BT thick film. The performance of the transducer was characterized and evaluated by the pulse-echo testing and wire phantom imaging operations. The BNT-BT thick film transducer exhibits a center frequency of 34 MHz, a -6 dB bandwidth of 26%, an axial resolution of 77 μm and a lateral resolution of 484 μm. The results suggest that lead-free BNT-BT thick film fabricated by tape-casting method is a promising lead-free candidate for high-frequency ultrasonic transducer applications.
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Affiliation(s)
- Junshan Zhang
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China.
- School of Equipment Engineering, Engineering University of People's Armed Police, Xi'an 710086, Shaanxi, China.
| | - Wei Ren
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China.
| | - Yantao Liu
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China.
| | - Xiaoqing Wu
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China.
| | - Chunlong Fei
- School of Microelectronics, Xidian University, Xi'an 740071, Shaanxi, China.
- Department of Ophthalmology and Biomedical Engineering, National Institutes of Health (NIH) Transducer Resource Center, University of Southern California, Los Angeles, CA 90089, USA.
| | - Yi Quan
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China.
| | - Qifa Zhou
- Department of Ophthalmology and Biomedical Engineering, National Institutes of Health (NIH) Transducer Resource Center, University of Southern California, Los Angeles, CA 90089, USA.
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Zhang T, Ou-Yang J, Yang X, Zhu B. Transferred PMN-PT Thick Film on Conductive Silver Epoxy. MATERIALS 2018; 11:ma11091621. [PMID: 30189636 PMCID: PMC6165122 DOI: 10.3390/ma11091621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 08/25/2018] [Accepted: 09/03/2018] [Indexed: 11/23/2022]
Abstract
Approximately 25 μm Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN-PT) thick film was synthesized based on a sol-gel/composite route. The obtained PMN-PT thick film was successfully transferred from the Silicon substrate to the conductive silver epoxy using a novel wet chemical method. The mechanism of this damage free transfer was explored and analyzed. Compared with the film on Silicon substrate, the transferred one exhibited superior dielectric, ferroelectric and piezoelectric properties. These promising results indicate that transferred PMN-PT thick film possesses the capability for piezoelectric device application, especially for ultrasound transducer fabrication. Most importantly, this chemical route opens a new path for transfer of thick film.
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Affiliation(s)
- Tao Zhang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Jun Ou-Yang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Xiaofei Yang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Benpeng Zhu
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
- State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 200050, China.
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A 35 MHz/105 MHz Dual-Element Focused Transducer for Intravascular Ultrasound Tissue Imaging Using the Third Harmonic. SENSORS 2018; 18:s18072290. [PMID: 30011948 PMCID: PMC6069256 DOI: 10.3390/s18072290] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 12/21/2022]
Abstract
The superharmonic imaging of tissue has the potential for high spatial and contrast resolutions, compared to the fundamental and second harmonic imaging. For this technique, the spectral bandwidth of an ultrasound transducer is divided for transmission of ultrasound and reception of its superharmonics (i.e., higher than the second harmonic). Due to the spectral division for the transmission and reception, transmitted ultrasound energy is not sufficient to induce superharmonics in media without using contrast agents, and it is difficult that a transducer has a −6 dB fractional bandwidth of higher than 100%. For the superharmonic imaging of tissue, thus, multi-frequency array transducers are the best choice if available; transmit and receive elements are separate and have different center frequencies. However, the construction of a multi-frequency transducer for intravascular ultrasound (IVUS) imaging is particularly demanding because of its small size of less than 1 mm. Here, we report a recently developed dual-element focused IVUS transducer for the third harmonic imaging of tissue, which consists of a 35-MHz element for ultrasound transmission and a 105-MHz element for third harmonic reception. For high quality third harmonic imaging, both elements were fabricated to have the same focus at 2.5 mm. The results of tissue mimicking phantom tests demonstrated that the third harmonic images produced by the developed transducer had higher spatial resolution and deeper imaging depth than the fundamental images.
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Munding CE, Chérin E, Jourard I, Weyers JJ, Goertz DE, Courtney BK, Foster FS. Development of a 3 French Dual-Frequency Intravascular Ultrasound Catheter. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:251-266. [PMID: 29150363 DOI: 10.1016/j.ultrasmedbio.2017.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 09/13/2017] [Accepted: 09/18/2017] [Indexed: 05/25/2023]
Abstract
Coronary plaque morphology, including plaque size and fibrous cap thickness, is thought to contribute to the risk of plaque rupture and future cardiac events. Dual-frequency intravascular ultrasound has been proposed as a possible technique to visualize both large-scale features and superficial detail of coronary plaque; however, it has not been found to be feasible within the constraints of a clinically functional intravascular ultrasound catheter. In this study, we describe the design and fabrication of a dual-frequency catheter using a bidirectional transducer stack with center frequencies of approximately 30 and 80 MHz. We describe how the high-frequency transducer achieves significantly improved axial and lateral resolution (16 and 120 µm, respectively, vs. 50 and 220 µm) at the expense of penetration depth. Finally, imaging of ex vivo human coronary artery segments reveals that the catheter can provide complementary images of the deeper arterial wall and superficial plaque features.
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Affiliation(s)
- Chelsea E Munding
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
| | | | - Isaac Jourard
- Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Jill J Weyers
- Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - David E Goertz
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Brian K Courtney
- Sunnybrook Research Institute, Toronto, Ontario, Canada; Schulich Heart Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Department of Medicine, University of Toronto, Toronto, Ontario, Canada; Conavi Medical Inc., Toronto, Ontario, Canada
| | - F Stuart Foster
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Sunnybrook Research Institute, Toronto, Ontario, Canada
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Fei C, Yang Y, Guo F, Lin P, Chen Q, Zhou Q, Sun L. PMN-PT Single Crystal Ultrasonic Transducer With Half-Concave Geometric Design for IVUS Imaging. IEEE Trans Biomed Eng 2017; 65:2087-2092. [PMID: 29989942 DOI: 10.1109/tbme.2017.2784437] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
As the key component of intravascular ultrasound (IVUS) imaging systems, traditional commercial side-looking IVUS transducers are flat and unfocused, which limits their lateral resolution. We propose a PMN-PT single crystal IVUS transducer with a half-concave geometry. This unique configuration makes it possible to conduct geometric focusing at a desired depth. To compare performances, the proposed and the traditional flat transducer with similar dimensions were fabricated. We determined that the half-concave transducer has a slightly higher center frequency (35 MHz), significantly broader -6 dB bandwidth (54%) but a higher insertion loss (-22.4 dB) compared to the flat transducer (32 MHz, 28%, and -19.3 dB, respectively). A significant enhancement of the lateral resolution was also confirmed. The experimental results are in agreement with the finite element simulation results. This preliminary investigation suggests that the half-concave geometry design is a promising approach in the development of focused IVUS transducers with broad bandwidth and high lateral resolution.
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Yu M, Li Y, Ma T, Shung KK, Zhou Q. Intravascular Ultrasound Imaging With Virtual Source Synthetic Aperture Focusing and Coherence Factor Weighting. IEEE TRANSACTIONS ON MEDICAL IMAGING 2017; 36:2171-2178. [PMID: 28692968 PMCID: PMC5812678 DOI: 10.1109/tmi.2017.2723479] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Intravascular ultrasound (IVUS) has been frequently used for coronary artery imaging clinically. More importantly, IVUS is the fundamental image modality for most advanced multimodality intravascular imaging techniques, since it provides a more comprehensive picture of vessel anatomy on which other imaging data can be superimposed. However, image quality in the deeper region is poor because of the downgraded lateral resolution and contrast-to-noise ratio (CNR). In this paper, we report on the application of an ultrasound beamforming method that combines virtual source synthetic aperture (VSSA) focusing and coherence factor weighting (CFW) to improve the IVUS image quality. The natural focal point of conventional IVUS transducer was treated as a virtual source that emits spherical waves within a certain region. Mono-static synthetic aperture focusing was conducted to achieve higher resolution. Coherence factor was calculated using delayed RF signals and applied to the synthesized beam to increase the CNR and focusing quality. The proposed method was tested through simulations in Field II and imaging experiments in both linear and rotational scans. The lateral resolution for linear scan mode is improved from 165-524 to 126-143 μm ; resolution for rotational scan mode improves by up to 42%. CNR improvement by up to 1.5 was observed on the anechoic cysts of different sizes and at different locations. Herein, it is demonstrated that the beamforming method, which combines VSSA and CFW, can significantly improve the IVUS image quality. This approach can be readily integrated into the current IVUS imaging system for enhanced clinical diagnosis.
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Affiliation(s)
| | | | - Teng Ma
- Teng Ma and Qifa Zhou are the corresponding authors for this work ( and )
| | - K. Kirk Shung
- Department of Biomedical Engineering, Los Angeles, CA 90089 USA
| | - Qifa Zhou
- Teng Ma and Qifa Zhou are the corresponding authors for this work ( and )
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Abstract
OBJECTIVE Photoacoustic (PA) imaging emerges as a unique tool to study biological samples based on optical absorption contrast. In PA imaging, piezoelectric transducers are commonly used to detect laser-induced ultrasonic waves. However, they typically lack adequate broadband sensitivity at ultrasonic frequency higher than 100 MHz, whereas their bulky size and optically opaque nature cause technical difficulties in integrating PA imaging with conventional optical imaging modalities. To overcome these limitations, optical methods of ultrasound detection were developed and shown their unique applications in PA imaging. METHODS We provide an overview of recent technological advances in optical methods of ultrasound detection and their applications in PA imaging. A general theoretical framework describing sensitivity, bandwidth, and angular responses of optical ultrasound detection is also introduced. RESULTS Optical methods of ultrasound detection can provide improved detection angle and sensitivity over significantly extended bandwidth. In addition, its versatile variants also offer additional advantages, such as device miniaturization, optical transparency, mechanical flexibility, minimal electrical/mechanical crosstalk, and potential noncontact PA imaging. CONCLUSION The optical ultrasound detection methods discussed in this review and their future evolution may play an important role in PA imaging for biomedical study and clinical diagnosis.
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Ma T, Zhou B, Hsiai TK, Shung KK. A Review of Intravascular Ultrasound-based Multimodal Intravascular Imaging: The Synergistic Approach to Characterizing Vulnerable Plaques. ULTRASONIC IMAGING 2016; 38:314-31. [PMID: 26400676 PMCID: PMC4803636 DOI: 10.1177/0161734615604829] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Catheter-based intravascular imaging modalities are being developed to visualize pathologies in coronary arteries, such as high-risk vulnerable atherosclerotic plaques known as thin-cap fibroatheroma, to guide therapeutic strategy at preventing heart attacks. Mounting evidences have shown three distinctive histopathological features-the presence of a thin fibrous cap, a lipid-rich necrotic core, and numerous infiltrating macrophages-are key markers of increased vulnerability in atherosclerotic plaques. To visualize these changes, the majority of catheter-based imaging modalities used intravascular ultrasound (IVUS) as the technical foundation and integrated emerging intravascular imaging techniques to enhance the characterization of vulnerable plaques. However, no current imaging technology is the unequivocal "gold standard" for the diagnosis of vulnerable atherosclerotic plaques. Each intravascular imaging technology possesses its own unique features that yield valuable information although encumbered by inherent limitations not seen in other modalities. In this context, the aim of this review is to discuss current scientific innovations, technical challenges, and prospective strategies in the development of IVUS-based multi-modality intravascular imaging systems aimed at assessing atherosclerotic plaque vulnerability.
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Affiliation(s)
- Teng Ma
- NIH Resource Center on Medical Ultrasonic Transducer Technology, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Bill Zhou
- David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Tzung K Hsiai
- Division of Cardiology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - K Kirk Shung
- NIH Resource Center on Medical Ultrasonic Transducer Technology, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
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29
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Shih CC, Lai TY, Huang CC. Evaluating the intensity of the acoustic radiation force impulse (ARFI) in intravascular ultrasound (IVUS) imaging: Preliminary in vitro results. ULTRASONICS 2016; 70:64-74. [PMID: 27135187 DOI: 10.1016/j.ultras.2016.04.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 04/18/2016] [Accepted: 04/19/2016] [Indexed: 05/13/2023]
Abstract
The ability to measure the elastic properties of plaques and vessels is significant in clinical diagnosis, particularly for detecting a vulnerable plaque. A novel concept of combining intravascular ultrasound (IVUS) imaging and acoustic radiation force impulse (ARFI) imaging has recently been proposed. This method has potential in elastography for distinguishing between the stiffness of plaques and arterial vessel walls. However, the intensity of the acoustic radiation force requires calibration as a standard for the further development of an ARFI-IVUS imaging device that could be used in clinical applications. In this study, a dual-frequency transducer with 11MHz and 48MHz was used to measure the association between the biological tissue displacement and the applied acoustic radiation force. The output intensity of the acoustic radiation force generated by the pushing element ranged from 1.8 to 57.9mW/cm(2), as measured using a calibrated hydrophone. The results reveal that all of the acoustic intensities produced by the transducer in the experiments were within the limits specified by FDA regulations and could still displace the biological tissues. Furthermore, blood clots with different hematocrits, which have elastic properties similar to the lipid pool of plaques, with stiffness ranging from 0.5 to 1.9kPa could be displaced from 1 to 4μm, whereas the porcine arteries with stiffness ranging from 120 to 291kPa were displaced from 0.4 to 1.3μm when an acoustic intensity of 57.9mW/cm(2) was used. The in vitro ARFI images of the artery with a blood clot and artificial arteriosclerosis showed a clear distinction of the stiffness distributions of the vessel wall. All the results reveal that ARFI-IVUS imaging has the potential to distinguish the elastic properties of plaques and vessels. Moreover, the acoustic intensity used in ARFI imaging has been experimentally quantified. Although the size of this two-element transducer is unsuitable for IVUS imaging, the experimental results reported herein can be applied in ARFI-IVUS imaging applications.
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Affiliation(s)
- Cho-Chiang Shih
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Ting-Yu Lai
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Chih-Chung Huang
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan.
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30
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Enhanced IVUS: Advances Allowing Higher Resolution and Integrated Devices. CURRENT CARDIOVASCULAR IMAGING REPORTS 2016. [DOI: 10.1007/s12410-016-9384-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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31
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Dixon AJ, Kilroy JP, Dhanaliwala AH, Chen JL, Phillips LC, Ragosta M, Klibanov AL, Wamhoff BR, Hossack JA. Microbubble-mediated intravascular ultrasound imaging and drug delivery. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2015; 62:1674-1685. [PMID: 26415129 DOI: 10.1109/tuffc.2015.007143] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Intravascular ultrasound (IVUS) provides radiation-free, real-time imaging and assessment of atherosclerotic disease in terms of anatomical, functional, and molecular composition. The primary clinical applications of IVUS imaging include assessment of luminal plaque volume and real-time image guidance for stent placement. When paired with microbubble contrast agents, IVUS technology may be extended to provide nonlinear imaging, molecular imaging, and therapeutic delivery modes. In this review, we discuss the development of emerging imaging and therapeutic applications that are enabled by the combination of IVUS imaging technology and microbubble contrast agents.
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32
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Yoon S, Williams J, Kang BJ, Yoon C, Cabrera-Munoz N, Jeong JS, Lee SG, Shung KK, Kim HH. Angled-focused 45 MHz PMN-PT single element transducer for intravascular ultrasound imaging. SENSORS AND ACTUATORS. A, PHYSICAL 2015; 228:16-22. [PMID: 25914443 PMCID: PMC4405812 DOI: 10.1016/j.sna.2015.02.037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A transducer with an angled and focused aperture for intravascular ultrasound imaging has been developed. The acoustic stack for the angled-focused transducer was made of PMN-PT single crystal with one matching layer, one protective coating layer, and a highly damped backing layer. It was then press-focused to a desired focal length and inserted into a thin needle housing with an angled tip. A transducer with an angled and unfocused aperture was also made, following the same fabrication procedure, to compare the performance of the two transducers. The focused and unfocused transducers were tested to measure their center frequencies, bandwidths, and spatial resolutions. Lateral resolution of the angled-focused transducer (AFT) improved more than two times compared to that of the angled-unfocused transducer (AUT). A tissue-mimicking phantom in water and a rabbit aorta tissue sample in rabbit blood were scanned using AFT and AUT. Imaging with AFT offered improved contrast, over imaging with AUT, of the tissue-mimicking phantom and the rabbit aorta tissue sample by 23 dB and 8 dB, respectively. The results show that AFT has strong potential to provide morphological and pathological information of coronary arteries with high resolution and high contrast.
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Affiliation(s)
- Sangpil Yoon
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Jay Williams
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Bong Jin Kang
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Changhan Yoon
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Nestor Cabrera-Munoz
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Jong Seob Jeong
- Department of Medical Biotechnology, Dongguk University, Seoul 100-715, Republic of Korea
| | - Sang Goo Lee
- IBULE Photonics Co., Ltd., Incheon, Republic of Korea
| | - K. Kirk Shung
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Hyung Ham Kim
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- Analogic Corporation, Peabody, MA 01960, USA
- Corresponding author at: 8 Centennial Drive, Peabody, MA 01960, USA. Tel.: +1 978 326 4511. (H.H. Kim)
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33
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Kawasaki M. An Integrated Backscatter Ultrasound Technique for Coronary Plaque Imaging. CURRENT CARDIOVASCULAR IMAGING REPORTS 2015. [DOI: 10.1007/s12410-015-9333-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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34
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Zhu B, Zhang Z, Ma T, Yang X, Li Y, Shung KK, Zhou Q. (100)-Textured KNN-based thick film with enhanced piezoelectric property for intravascular ultrasound imaging. APPLIED PHYSICS LETTERS 2015; 106:173504. [PMID: 25991874 PMCID: PMC4417015 DOI: 10.1063/1.4919387] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 04/17/2015] [Indexed: 06/01/2023]
Abstract
Using tape-casting technology, 35 μm free-standing (100)-textured Li doped KNN (KNLN) thick film was prepared by employing NaNbO3 (NN) as template. It exhibited similar piezoelectric behavior to lead containing materials: a longitudinal piezoelectric coefficient (d33) of ∼150 pm/V and an electromechanical coupling coefficient (kt ) of 0.44. Based on this thick film, a 52 MHz side-looking miniature transducer with a bandwidth of 61.5% at -6 dB was built for Intravascular ultrasound (IVUS) imaging. In comparison with 40 MHz PMN-PT single crystal transducer, the rabbit aorta image had better resolution and higher noise-to-signal ratio, indicating that lead-free (100)-textured KNLN thick film may be suitable for IVUS (>50 MHz) imaging.
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Affiliation(s)
| | - Zhiqiang Zhang
- Key Laboratory of Inorganic Functional Materials and Devices , Chinese Academy of Sciences, Shanghai 200050, China
| | - Teng Ma
- Department of Biomedical Engineering, NIH Transducer Resource Center, University of Southern California , Los Angeles, California 90089-1111, USA
| | - Xiaofei Yang
- School of Optical and Electronic Information, Huazhong University of Science and Technology , Wuhan 430074, China
| | - Yongxiang Li
- Key Laboratory of Inorganic Functional Materials and Devices , Chinese Academy of Sciences, Shanghai 200050, China
| | - K Kirk Shung
- Department of Biomedical Engineering, NIH Transducer Resource Center, University of Southern California , Los Angeles, California 90089-1111, USA
| | - Qifa Zhou
- Department of Biomedical Engineering, NIH Transducer Resource Center, University of Southern California , Los Angeles, California 90089-1111, USA
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35
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Colchester RJ, Zhang EZ, Mosse CA, Beard PC, Papakonstantinou I, Desjardins AE. Broadband miniature optical ultrasound probe for high resolution vascular tissue imaging. BIOMEDICAL OPTICS EXPRESS 2015; 6:1502-11. [PMID: 25909031 PMCID: PMC4399686 DOI: 10.1364/boe.6.001502] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 01/30/2015] [Accepted: 02/02/2015] [Indexed: 05/20/2023]
Abstract
An all-optical ultrasound probe for vascular tissue imaging was developed. Ultrasound was generated by pulsed laser illumination of a functionalized carbon nanotube composite coating on the end face of an optical fiber. Ultrasound was detected with a Fabry-Pérot (FP) cavity on the end face of an adjacent optical fiber. The probe diameter was < 0.84 mm and had an ultrasound bandwidth of ~20 MHz. The probe was translated across the tissue sample to create a virtual linear array of ultrasound transmit/receive elements. At a depth of 3.5 mm, the axial resolution was 64 µm and the lateral resolution was 88 µm, as measured with a carbon fiber target. Vascular tissues from swine were imaged ex vivo and good correspondence to histology was observed.
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Affiliation(s)
- Richard J. Colchester
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT,
UK
| | - Edward Z. Zhang
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT,
UK
| | - Charles A. Mosse
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT,
UK
| | - Paul C. Beard
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT,
UK
| | - Ioannis Papakonstantinou
- Department of Electronic and Electrical Engineering, University College London, Gower Street, London, WC1E 6BT,
UK
| | - Adrien E. Desjardins
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT,
UK
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36
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Qiu W, Chen Y, Wong CM, Liu B, Dai J, Zheng H. A novel dual-frequency imaging method for intravascular ultrasound applications. ULTRASONICS 2015; 57:31-5. [PMID: 25454093 DOI: 10.1016/j.ultras.2014.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 10/07/2014] [Accepted: 10/08/2014] [Indexed: 05/25/2023]
Abstract
Intravascular ultrasound (IVUS), which is able to delineate internal structures of vessel wall with fine spatial resolution, has greatly enriched the knowledge of coronary atherosclerosis. A novel dual-frequency imaging method is proposed in this paper for intravascular imaging applications. A probe combined two ultrasonic transducer elements with different center frequencies (36 MHz and 78 MHz) is designed and fabricated with PMN-PT single crystal material. It has the ability to balance both imaging depth and resolution, which are important imaging parameters for clinical test. A dual-channel imaging platform is also proposed for real-time imaging, and this platform has been proven to support programmable processing algorithms, flexible imaging control, and raw RF data acquisition for IVUS applications. Testing results show that the -6 dB axial and lateral imaging resolutions of low-frequency ultrasound are 78 and 132 μm, respectively. In terms of high-frequency ultrasound, axial and lateral resolutions are determined to be as high as 34 and 106 μm. In vitro intravascular imaging on healthy swine aorta is conducted to demonstrate the performance of the dual-frequency imaging method for IVUS applications.
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Affiliation(s)
- Weibao Qiu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Yan Chen
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China; Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China
| | - Chi-Man Wong
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China; Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China
| | - Baoqiang Liu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Jiyan Dai
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China; Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Hairong Zheng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
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37
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Zhangjian L, Weiwei S, Yongjia X, Zhile H, Yaoyao C. Different layer thickness influences of a 50MHz intravascular ultrasound transducer. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2014:542-5. [PMID: 25570016 DOI: 10.1109/embc.2014.6943648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In order to design a 50MHz intravascular ultrasound (IVUS) transducer with good pulse-echo responses, in this paper, a finite element model (FEM) was built to simulate the transducer acoustic performances with different layer thicknesses. According to comparisons of the acoustic fields and the admittance curves, the optimum thickness parameters are gained. And then, an IVUS PZT transducer with controlled layer thicknesses was fabricated and tested. The results of pulse-echo response tests shown this transducer with the optimum parameters had very good performance. The central frequency is 45.5MHz and its bandwidth was about 50% which are suitable for intravascular imaging.
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38
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Kawasaki M. An integrated backscatter ultrasound technique for the detection of coronary and carotid atherosclerotic lesions. SENSORS 2015; 15:979-94. [PMID: 25574937 PMCID: PMC4327059 DOI: 10.3390/s150100979] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 12/15/2014] [Indexed: 01/06/2023]
Abstract
The instability of carotid and coronary plaques has been reported to be associated with acute coronary syndrome, strokes and other cerebrovascular events. Therefore, recognition of the tissue characteristics of carotid and coronary plaques is important to understand and prevent coronary and cerebral artery disease. Recently, an ultrasound integrated backscatter (IB) technique has been developed. The ultrasound IB power ratio is a function of the difference in acoustic characteristic impedance between the medium and target tissue, and the acoustic characteristic impedance is determined by the density of tissue multiplied by the speed of sound. This concept allows for tissue characterization of carotid and coronary plaques for risk stratification of patients with coronary and cerebral artery disease. Two- and three-dimensional IB color-coded maps for the evaluation of tissue components consist of four major components: fibrous, dense fibrosis, lipid pool and calcification. Although several ultrasound techniques using special mathematical algorithms have been reported, a growing body of literature has shown the reliability and usefulness of the IB technique for the tissue characterization of carotid and coronary plaques. This review summarizes concepts, experimental procedures, image reliability and the application of the IB technique. Furthermore, the IB technique is compared with other techniques.
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Affiliation(s)
- Masanori Kawasaki
- Department of Cardiology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194, Japan.
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39
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Ma T, Yu M, Chen Z, Fei C, Shung KK, Zhou Q. Multi-frequency intravascular ultrasound (IVUS) imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2015; 62:97-107. [PMID: 25585394 PMCID: PMC4522164 DOI: 10.1109/tuffc.2014.006679] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Acute coronary syndrome (ACS) is frequently associated with the sudden rupture of a vulnerable atherosclerotic plaque within the coronary artery. Several unique physiological features, including a thin fibrous cap accompanied by a necrotic lipid core, are the targeted indicators for identifying the vulnerable plaques. Intravascular ultrasound (IVUS), a catheter-based imaging technology, has been routinely performed in clinics for more than 20 years to describe the morphology of the coronary artery and guide percutaneous coronary interventions. However, conventional IVUS cannot facilitate the risk assessment of ACS because of its intrinsic limitations, such as insufficient resolution. Renovation of the IVUS technology is essentially needed to overcome the limitations and enhance the coronary artery characterization. In this paper, a multi-frequency intravascular ultrasound (IVUS) imaging system was developed by incorporating a higher frequency IVUS transducer (80 to 150 MHz) with the conventional IVUS (30-50 MHz) system. The newly developed system maintains the advantage of deeply penetrating imaging with the conventional IVUS, while offering an improved higher resolution image with IVUS at a higher frequency. The prototyped multifrequency catheter has a clinically compatible size of 0.95 mm and a favorable capability of automated image co-registration. In vitro human coronary artery imaging has demonstrated the feasibility and superiority of the multi-frequency IVUS imaging system to deliver a more comprehensive visualization of the coronary artery. This ultrasonic-only intravascular imaging technique, based on a moderate refinement of the conventional IVUS system, is not only cost-effective from the perspective of manufacturing and clinical practice, but also holds the promise of future translation into clinical benefits.
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Affiliation(s)
- Teng Ma
- Department of Biomedical Engineering and the National Institutes of Health (NIH) Resource Center for Medical Ultrasonic Transducer Technology, University of Southern California, Los Angeles, CA
| | - Mingyue Yu
- Department of Biomedical Engineering and the National Institutes of Health (NIH) Resource Center for Medical Ultrasonic Transducer Technology, University of Southern California, Los Angeles, CA
| | - Zeyu Chen
- Department of Biomedical Engineering and the National Institutes of Health (NIH) Resource Center for Medical Ultrasonic Transducer Technology, University of Southern California, Los Angeles, CA
| | - Chunlong Fei
- School of Physics and Technology, Wuhan University, Wuhan, Hubei, China
| | - K. Kirk Shung
- Department of Biomedical Engineering and the National Institutes of Health (NIH) Resource Center for Medical Ultrasonic Transducer Technology, University of Southern California, Los Angeles, CA
| | - Qifa Zhou
- Department of Biomedical Engineering and the National Institutes of Health (NIH) Resource Center for Medical Ultrasonic Transducer Technology, University of Southern California, Los Angeles, CA
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40
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Li X, Ma T, Tian J, Han P, Zhou Q, Shung KK. Micromachined PIN-PMN-PT crystal composite transducer for high-frequency intravascular ultrasound (IVUS) imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2014; 61:1171-8. [PMID: 24960706 PMCID: PMC4414317 DOI: 10.1109/tuffc.2014.3016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In this paper, we report the use of micromachined PbIn1/2Nb1/2O3-PbMg1/3Nb2/3O3-PbTiO 3 (PIN-PMNPT) single crystal 1-3 composite material for intravascular ultrasound (IVUS) imaging application. The effective electromechanical coupling coefficient kt(eff) of the composite was measured to be 0.75 to 0.78. Acoustic impedance was estimated to be 20 MRayl. Based on the composite, needle-type and flexible-type IVUS transducers were fabricated. The composite transducer achieved an 86% bandwidth at the center frequency of 41 MHz, which resulted in a 43 μm axial resolution. Ex vivo IVUS imaging was conducted to demonstrate the improvement of axial resolution. The composite transducer was capable of identifying the three layers of a cadaver coronary artery specimen with high resolution. The PIN-PMN-PT-based composite has superior piezoelectric properties comparable to PMN-PT-based composite and its thermal stability is higher than PMN-PT. PIN-PMN-PT crystal can be an alternative approach for fabricating high-frequency composite, instead of using PMN-PT.
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41
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Kilroy JP, Patil AV, Rychak JJ, Hossack JA. An IVUS transducer for microbubble therapies. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2014; 61:441-9. [PMID: 24569249 PMCID: PMC4136497 DOI: 10.1109/tuffc.2014.2929] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
There is interest in examining the potential of modified intravascular ultrasound (IVUS) catheters to facilitate dual diagnostic and therapeutic roles using ultrasound plus microbubbles for localized drug delivery to the vessel wall. The goal of this study was to design, prototype, and validate an IVUS transducer for microbubble-based drug delivery. A 1-D acoustic radiation force model and finite element analysis guided the design of a 1.5-MHz IVUS transducer. Using the IVUS transducer, biotinylated microbubbles were displaced in water and bovine whole blood to the streptavidin-coated wall of a flow phantom by a 1.5-MHz center frequency, peak negative pressure = 70 kPa pulse with varying pulse repetition frequency (PRF) while monitoring microbubble adhesion with ultrasound. A fit was applied to the RF data to extract a time constant (τ). As PRF was increased in water, the time constant decreased (τ = 32.6 s, 1 kHz vs. τ = 8.2 s, 6 kHz), whereas in bovine whole blood an adhesion-no adhesion transition was found for PRFs ≥ 8 kHz. Finally, a fluorophore was delivered to an ex vivo swine artery using microbubbles and the IVUS transducer, resulting in a 6.6-fold increase in fluorescence. These results indicate the importance of PRF (or duty factor) for IVUS acoustic radiation force microbubble displacement and the potential for IVUS and microbubbles to provide localized drug delivery.
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Affiliation(s)
- Joseph P. Kilroy
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | | | - Joshua J. Rychak
- Targeson Inc. and the Department of Bioengineering, University of California, San Diego, CA
| | - John A. Hossack
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
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Nakatani S, Proniewska K, Pociask E, Paoletti G, de Winter S, Muramatsu T, Bruining N. How clinically effective is intravascular ultrasound in interventional cardiology? Present and future perspectives. Expert Rev Med Devices 2014; 10:735-49. [DOI: 10.1586/17434440.2013.841353] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Yan X, Ji H, Lam KH, Chen R, Zheng F, Ren W, Zhou Q, Shung KK. Lead-free BNT composite film for high-frequency broadband ultrasonic transducer applications. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2013; 60:1533-1537. [PMID: 25004521 DOI: 10.1109/tuffc.2013.2726] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A lead-free Bi0.5Na0.5TiO3 (BNT) piezoelectric composite thick film with a thickness of ~11 μm has been fabricated using a modified sol-gel method. Dielectric constant, remnant polarization, and coercive field of the BNT composite film were found to be 1018, 22.6 μC/cm2, and 76.1 kV/cm, respectively. The film was used to fabricate a high-frequency needle transducer and the performance of the transducer was measured. The transducer without a matching layer exhibits a center frequency of 98 MHz and a -6-dB bandwidth of 86%. A wire phantom image acquired using the transducer shows an axial resolution of 15 ¿m and lateral resolution of 68 μm, respectively. Results from this study suggest that the BNT composite film is a promising lead-free piezoelectric material for high-frequency broadband ultrasonic transducer applications.
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Yan X, Lam KH, Li X, Chen R, Ren W, Ren X, Zhou Q, Shung KK. Lead-free intravascular ultrasound transducer using BZT-50BCT ceramics. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2013; 60:1272-6. [PMID: 25004492 PMCID: PMC4090606 DOI: 10.1109/tuffc.2013.2692] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
This paper reports the fabrication and evaluation of a high-frequency ultrasonic transducer based on a new lead-free piezoelectric material for intravascular imaging application. Lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO4(BZT-50BCT) ceramic with a high dielectric constant (~2800) was employed to develop a high-frequency (~30 MHz) needle-type ultrasonic transducer. With superior piezoelectric performance (piezoelectric coefficient d33 ~ 600 pC/N), the lead-free transducer was found to exhibit a -6-dB bandwidth of 53% with an insertion loss of 18.7 dB. In vitro intravascular ultrasound (IVUS) imaging of a human cadaver coronary artery was performed to demonstrate the potential of the lead-free transducer for biomedical imaging applications. This is the first time that a lead-free transducer has been used for IVUS imaging application. The experimental results suggest that the BZT-50BCT ceramic is a promising lead-free piezoelectric material for high-frequency intravascular imaging applications.
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Qiu W, Chen Y, Li X, Yu Y, Cheng WF, Tsang FK, Zhou Q, Shung KK, Dai J, Sun L. An open system for intravascular ultrasound imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2012; 59:2201-9. [PMID: 23143570 PMCID: PMC3760234 DOI: 10.1109/tuffc.2012.2446] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Visualization of the blood vessels can provide valuable morphological information for diagnosis and therapy strategies for cardiovascular disease. Intravascular ultrasound (IVUS) is able to delineate internal structures of vessel wall with fine spatial resolution. However, the developed IVUS is insufficient to identify the fibrous cap thickness and tissue composition of atherosclerotic lesions. Novel imaging strategies have been proposed, such as increasing the center frequency of ultrasound or using a modulated excitation technique to improve the accuracy of diagnosis. Dual-mode tomography combining IVUS with optical tomography has also been developed to determine tissue morphology and characteristics. The implementation of these new imaging methods requires an open system that allows users to customize the system for various studies. This paper presents the development of an IVUS system that has open structures to support various imaging strategies. The system design is based on electronic components and printed circuit board, and provides reconfigurable hardware implementation, programmable image processing algorithms, flexible imaging control, and raw RF data acquisition. In addition, the proposed IVUS system utilized a miniaturized ultrasound transducer constructed using PMNPT single crystal for better piezoelectric constant and electromechanical coupling coefficient than traditional lead zirconate titanate (PZT) ceramics. Testing results showed that the IVUS system could offer a minimum detectable signal of 25 μV, allowing a 51 dB dynamic range at 47 dB gain, with a frequency range from 20 to 80 MHz. Finally, phantom imaging, in vitro IVUS vessel imaging, and multimodality imaging with photoacoustics were conducted to demonstrate the performance of the open system.
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Affiliation(s)
- Weibao Qiu
- Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Yan Chen
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Xiang Li
- National Institutes of Health Resource Center for Medical Ultrasonic Transducer Technology and Department of Biomedical Engineering, University of Southern California, Los Angeles, CA
| | - Yanyan Yu
- Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Wang Fai Cheng
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Fu Keung Tsang
- Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Qifa Zhou
- National Institutes of Health Resource Center for Medical Ultrasonic Transducer Technology and Department of Biomedical Engineering, University of Southern California, Los Angeles, CA
| | - K. Kirk Shung
- National Institutes of Health Resource Center for Medical Ultrasonic Transducer Technology and Department of Biomedical Engineering, University of Southern California, Los Angeles, CA
| | - Jiyan Dai
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Lei Sun
- Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China ()
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Li X, Wei W, Zhou Q, Shung KK, Chen Z. Intravascular photoacoustic imaging at 35 and 80 MHz. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:106005. [PMID: 23224004 PMCID: PMC3461096 DOI: 10.1117/1.jbo.17.10.106005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The catheter-based intravascular photoacoustic (IVPA) imaging for diagnosing atherosclerosis, which can provide optical absorption contrast of the arterial wall besides acoustic scattering contrast from the conventional intravascular ultrasound (IVUS) imaging, has been intensively researched recently. The resolution of IVPA is determined by the frequency bandwidth of an ultrasonic transducer. Higher resolution can be achieved by increasing the transducer's working frequency and bandwidth. We introduce IVPA imaging at 35 and 80 MHz by using newly designed integrated IVUS/IVPA probes. This is the first time IVPA has been achieved as high as 80 MHz. Six-micrometer tungsten wires were imaged to evaluate the probes' spatial resolutions and beam patterns. Healthy rabbit aorta was imaged in vitro. Imaging results show that IVPA has superior contrast over IVUS in identifying the arterial wall, and IVPA at 80 MHz demonstrates extraordinary resolution (35 μm) compared to 35 MHz.
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Affiliation(s)
- Xiang Li
- University of Southern California, Department of Biomedical Engineering, NIH Ultrasonic Transducer Resource Center, Los Angeles, California 90089
| | - Wei Wei
- University of California, Irvine, Beckman Laser Institute, Irvine, California 92612
- Wuhan University, Department of Physics and Key Laboratory of Acoustic and Photonic Materials and Devices, Wuhan 430072, China
| | - Qifa Zhou
- University of Southern California, Department of Biomedical Engineering, NIH Ultrasonic Transducer Resource Center, Los Angeles, California 90089
- Address all correspondence to: Qifa Zhou, University of Southern California, NIH Ultrasonic Transducer Resource Center, 1042 Downey Way, University Park, Los Angeles, California 90089. Tel: 213-740-9475; Fax: 213-821-3897; E-mail: ; Zhongping Chen, University of California, Irvine, Beckman Laser Institute, 1002 Health Sciences Road East, Irvine, California 92612. Tel: 949-824-1247; Fax: 949-824-8413; E-mail: .
| | - K. Kirk Shung
- University of Southern California, Department of Biomedical Engineering, NIH Ultrasonic Transducer Resource Center, Los Angeles, California 90089
| | - Zhongping Chen
- University of California, Irvine, Beckman Laser Institute, Irvine, California 92612
- University of California, Irvine, Department of Biomedical Engineering, Irvine, California 92697
- University of California, Irvine, Edwards Lifesciences Center for Advanced Cardiovascular Technology, Irvine, California 92697
- Address all correspondence to: Qifa Zhou, University of Southern California, NIH Ultrasonic Transducer Resource Center, 1042 Downey Way, University Park, Los Angeles, California 90089. Tel: 213-740-9475; Fax: 213-821-3897; E-mail: ; Zhongping Chen, University of California, Irvine, Beckman Laser Institute, 1002 Health Sciences Road East, Irvine, California 92612. Tel: 949-824-1247; Fax: 949-824-8413; E-mail: .
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