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Wan H, Zhou Y, Ying L, Meng J, Song L, Xia J. Enabling high-speed wide-field dynamic imaging in multifocal photoacoustic computed microscopy: a simulation study. APPLIED OPTICS 2016; 55:3724-9. [PMID: 27168282 PMCID: PMC4877034 DOI: 10.1364/ao.55.003724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Photoacoustic-computed microscopy (PACM) is an emerging technology that employs thousands of optical foci to provide wide-field high-resolution images of tissue optical absorption. A major limitation of PACM is the slow imaging speed, limiting its usage in dynamic imaging. In this study, we improved the speed through a two-step approach. First, we employed compressed sensing with partially known support to reduce the transducer element number, which subsequently improved the imaging speed at each optical scanning step. Second, we use the high-speed low-resolution image acquired without microlens array to inform dynamic changes in the high-resolution PACM image. Combining both approaches, we achieved high-resolution dynamic imaging over a wide field.
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Affiliation(s)
- Hongying Wan
- Department of Biomedical Engineering, University at Buffalo, the State University of New York, Buffalo, NY, 14260, USA
| | - Yihang Zhou
- Department of Biomedical Engineering, University at Buffalo, the State University of New York, Buffalo, NY, 14260, USA
| | - Leslie Ying
- Department of Biomedical Engineering, University at Buffalo, the State University of New York, Buffalo, NY, 14260, USA
| | - Jing Meng
- College of Information Science and Engineering, Qufu Normal University, 80 Yantai Road North, Rizhao, Shandong 276826, China
| | - Liang Song
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Boulevard, Shenzhen 518055, China
| | - Jun Xia
- Department of Biomedical Engineering, University at Buffalo, the State University of New York, Buffalo, NY, 14260, USA
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52
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Wearable 3-D Photoacoustic Tomography for Functional Brain Imaging in Behaving Rats. Sci Rep 2016; 6:25470. [PMID: 27146026 PMCID: PMC4857106 DOI: 10.1038/srep25470] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 04/18/2016] [Indexed: 01/11/2023] Open
Abstract
Understanding the relationship between brain function and behavior remains a major challenge in neuroscience. Photoacoustic tomography (PAT) is an emerging technique that allows for noninvasive in vivo brain imaging at micrometer-millisecond spatiotemporal resolution. In this article, a novel, miniaturized 3D wearable PAT (3D-wPAT) technique is described for brain imaging in behaving rats. 3D-wPAT has three layers of fully functional acoustic transducer arrays. Phantom imaging experiments revealed that the in-plane X-Y spatial resolutions were ~200 μm for each acoustic detection layer. The functional imaging capacity of 3D-wPAT was demonstrated by mapping the cerebral oxygen saturation via multi-wavelength irradiation in behaving hyperoxic rats. In addition, we demonstrated that 3D-wPAT could be used for monitoring sensory stimulus-evoked responses in behaving rats by measuring hemodynamic responses in the primary visual cortex during visual stimulation. Together, these results show the potential of 3D-wPAT for brain study in behaving rodents.
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53
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Van de Sompel D, Sasportas LS, Jokerst JV, Gambhir SS. Comparison of Deconvolution Filters for Photoacoustic Tomography. PLoS One 2016; 11:e0152597. [PMID: 27031832 PMCID: PMC4816281 DOI: 10.1371/journal.pone.0152597] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 03/16/2016] [Indexed: 11/18/2022] Open
Abstract
In this work, we compare the merits of three temporal data deconvolution methods for use in the filtered backprojection algorithm for photoacoustic tomography (PAT). We evaluate the standard Fourier division technique, the Wiener deconvolution filter, and a Tikhonov L-2 norm regularized matrix inversion method. Our experiments were carried out on subjects of various appearances, namely a pencil lead, two man-made phantoms, an in vivo subcutaneous mouse tumor model, and a perfused and excised mouse brain. All subjects were scanned using an imaging system with a rotatable hemispherical bowl, into which 128 ultrasound transducer elements were embedded in a spiral pattern. We characterized the frequency response of each deconvolution method, compared the final image quality achieved by each deconvolution technique, and evaluated each method's robustness to noise. The frequency response was quantified by measuring the accuracy with which each filter recovered the ideal flat frequency spectrum of an experimentally measured impulse response. Image quality under the various scenarios was quantified by computing noise versus resolution curves for a point source phantom, as well as the full width at half maximum (FWHM) and contrast-to-noise ratio (CNR) of selected image features such as dots and linear structures in additional imaging subjects. It was found that the Tikhonov filter yielded the most accurate balance of lower and higher frequency content (as measured by comparing the spectra of deconvolved impulse response signals to the ideal flat frequency spectrum), achieved a competitive image resolution and contrast-to-noise ratio, and yielded the greatest robustness to noise. While the Wiener filter achieved a similar image resolution, it tended to underrepresent the lower frequency content of the deconvolved signals, and hence of the reconstructed images after backprojection. In addition, its robustness to noise was poorer than that of the Tikhonov filter. The performance of the Fourier filter was found to be the poorest of all three methods, based on the reconstructed images' lowest resolution (blurriest appearance), generally lowest contrast-to-noise ratio, and lowest robustness to noise. Overall, the Tikhonov filter was deemed to produce the most desirable image reconstructions.
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Affiliation(s)
- Dominique Van de Sompel
- Molecular Imaging Program at Stanford (MIPS), Stanford University School of Medicine, Stanford University, Stanford, CA 94305, United States of America
| | - Laura S. Sasportas
- Molecular Imaging Program at Stanford (MIPS), Stanford University School of Medicine, Stanford University, Stanford, CA 94305, United States of America
| | - Jesse V. Jokerst
- Department of NanoEngineering, UC San Diego, La Jolla, CA 92093, United States of America
| | - Sanjiv S. Gambhir
- Molecular Imaging Program at Stanford (MIPS), Stanford University School of Medicine, Stanford University, Stanford, CA 94305, United States of America
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54
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Hui J, Li R, Phillips EH, Goergen CJ, Sturek M, Cheng JX. Bond-selective photoacoustic imaging by converting molecular vibration into acoustic waves. PHOTOACOUSTICS 2016; 4:11-21. [PMID: 27069873 PMCID: PMC4811918 DOI: 10.1016/j.pacs.2016.01.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 01/11/2016] [Indexed: 05/04/2023]
Abstract
The quantized vibration of chemical bonds provides a way of detecting specific molecules in a complex tissue environment. Unlike pure optical methods, for which imaging depth is limited to a few hundred micrometers by significant optical scattering, photoacoustic detection of vibrational absorption breaks through the optical diffusion limit by taking advantage of diffused photons and weak acoustic scattering. Key features of this method include both high scalability of imaging depth from a few millimeters to a few centimeters and chemical bond selectivity as a novel contrast mechanism for photoacoustic imaging. Its biomedical applications spans detection of white matter loss and regeneration, assessment of breast tumor margins, and diagnosis of vulnerable atherosclerotic plaques. This review provides an overview of the recent advances made in vibration-based photoacoustic imaging and various biomedical applications enabled by this new technology.
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Affiliation(s)
- Jie Hui
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907, USA
| | - Rui Li
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Evan H. Phillips
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Craig J. Goergen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Michael Sturek
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Ji-Xin Cheng
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
- Purdue Institute of Inflammation, Immunology and Infectious Diseases, West Lafayette, IN 47907, USA
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55
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Lutzweiler C, Tzoumas S, Rosenthal A, Ntziachristos V, Razansky D. High-Throughput Sparsity-Based Inversion Scheme for Optoacoustic Tomography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2016; 35:674-684. [PMID: 26469127 DOI: 10.1109/tmi.2015.2490799] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The concept of sparsity is extensively exploited in the fields of data acquisition and image processing, contributing to better signal-to-noise and spatio-temporal performance of the various imaging methods. In the field of optoacoustic tomography, the image reconstruction problem is often characterized by computationally extensive inversion of very large datasets, for instance when acquiring volumetric multispectral data with high temporal resolution. In this article we seek to accelerate accurate model-based optoacoustic inversions by identifying various sources of sparsity in the forward and inverse models as well as in the single- and multi-frame representation of the projection data. These sources of sparsity are revealed through appropriate transformations in the signal, model and image domains and are subsequently exploited for expediting image reconstruction. The sparsity-based inversion scheme was tested with experimental data, offering reconstruction speed enhancement by a factor of 40 to 700 times as compared with the conventional iterative model-based inversions while preserving similar image quality. The demonstrated results pave the way for achieving real-time performance of model-based reconstruction in multi-dimensional optoacoustic imaging.
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Cho Y, Chang CC, Wang LV, Zou J. Micromachined Silicon Parallel Acoustic Delay Lines as Time Delayed Ultrasound Detector Array for Real-Time Photoacoustic Tomography. JOURNAL OF OPTICS (2010) 2016; 18:10.1088/2040-8978/18/2/024003. [PMID: 31998470 PMCID: PMC6988759 DOI: 10.1088/2040-8978/18/2/024003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
This paper reports the development of a new 16-channel parallel acoustic delay line (PADL) array for real-time photoacoustic tomography (PAT). The PADLs were directly fabricated from single-crystalline silicon substrates using deep reactive ion etching. Compared with other acoustic delay lines (e.g., optical fibers), the micromachined silicon PADLs offer higher acoustic transmission efficiency, smaller form factor, easier assembly, and mass production capability. To demonstrate its real-time photoacoustic imaging capability, the silicon PADL array was interfaced with one single-element ultrasonic transducer followed by one channel of DAQ electronics to receive 16 channels of photoacoustic signals simultaneously. A PAT image of an optically-absorbing target embedded in an optically-scattering phantom was reconstructed, which matched well with the actual size of the imaged target. Because the silicon PADL array allows a signal-to-channel reduction ratio of 16:1, it could significantly simplify the design and construction of ultrasonic receivers for real-time PAT.
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Affiliation(s)
- Y Cho
- Texas A&M University, Department of Electrical and Computer Engineering, College Station, Texas 77843, United States
| | - C-C Chang
- Texas A&M University, Department of Electrical and Computer Engineering, College Station, Texas 77843, United States
| | - L V Wang
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130, United States
| | - J Zou
- Texas A&M University, Department of Electrical and Computer Engineering, College Station, Texas 77843, United States
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57
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Wang D, Wu Y, Xia J. Review on photoacoustic imaging of the brain using nanoprobes. NEUROPHOTONICS 2016; 3:010901. [PMID: 26740961 PMCID: PMC4699324 DOI: 10.1117/1.nph.3.1.010901] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 11/24/2015] [Indexed: 05/18/2023]
Abstract
Photoacoustic (PA) tomography (PAT) is a hybrid imaging modality that integrates rich optical contrasts with a high-ultrasonic spatial resolution in deep tissue. Among various imaging applications, PA neuroimaging is becoming increasingly important as it nicely complements the limitations of conventional neuroimaging modalities, such as the low-temporal resolution in magnetic resonance imaging and the low depth-to-resolution ratio in optical microscopy/tomography. In addition, the intrinsic hemoglobin contrast PA neuroimaging has also been greatly improved by recent developments in nanoparticles (NPs). For instance, near-infrared absorbing NPs greatly enhanced the vascular contrast in deep-brain PAT; tumor-targeting NPs allowed highly sensitive and highly specific delineation of brain tumors; and multifunctional NPs enabled comprehensive examination of the brain through multimodal imaging. We aim to give an overview of NPs used in PA neuroimaging. Classifications of various NPs used in PAT will be introduced at the beginning, followed by an overview of PA neuroimaging systems, and finally we will discuss major applications of NPs in PA neuroimaging and highlight representative studies.
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Affiliation(s)
- Depeng Wang
- State University of New York, University at Buffalo, Department of Biomedical Engineering, 208 Bonner Hall, Buffalo, New York 14260, United States
| | - Yun Wu
- State University of New York, University at Buffalo, Department of Biomedical Engineering, 208 Bonner Hall, Buffalo, New York 14260, United States
| | - Jun Xia
- State University of New York, University at Buffalo, Department of Biomedical Engineering, 208 Bonner Hall, Buffalo, New York 14260, United States
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58
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Kneipp M, Turner J, Estrada H, Rebling J, Shoham S, Razansky D. Effects of the murine skull in optoacoustic brain microscopy. JOURNAL OF BIOPHOTONICS 2016; 9:117-23. [PMID: 25919801 DOI: 10.1002/jbio.201400152] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/05/2015] [Accepted: 03/24/2015] [Indexed: 05/20/2023]
Abstract
Despite the great promise behind the recent introduction of optoacoustic technology into the arsenal of small-animal neuroimaging methods, a variety of acoustic and light-related effects introduced by adult murine skull severely compromise the performance of optoacoustics in transcranial imaging. As a result, high-resolution noninvasive optoacoustic microscopy studies are still limited to a thin layer of pial microvasculature, which can be effectively resolved by tight focusing of the excitation light. We examined a range of distortions introduced by an adult murine skull in transcranial optoacoustic imaging under both acoustically- and optically-determined resolution scenarios. It is shown that strong low-pass filtering characteristics of the skull may significantly deteriorate the achievable spatial resolution in deep brain imaging where no light focusing is possible. While only brain vasculature with a diameter larger than 60 µm was effectively resolved via transcranial measurements with acoustic resolution, significant improvements are seen through cranial windows and thinned skull experiments.
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Affiliation(s)
- Moritz Kneipp
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
- Faculty of Medicine and Faculty of Electrical Engineering and Information Technology, Technische Universität München, Germany
| | - Jake Turner
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
- Faculty of Medicine and Faculty of Electrical Engineering and Information Technology, Technische Universität München, Germany
| | - Héctor Estrada
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
| | - Johannes Rebling
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
- Faculty of Medicine and Faculty of Electrical Engineering and Information Technology, Technische Universität München, Germany
| | - Shy Shoham
- Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel
| | - Daniel Razansky
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany.
- Faculty of Medicine and Faculty of Electrical Engineering and Information Technology, Technische Universität München, Germany.
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59
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Klibanov AL, Hossack JA. Ultrasound in Radiology: From Anatomic, Functional, Molecular Imaging to Drug Delivery and Image-Guided Therapy. Invest Radiol 2015; 50:657-70. [PMID: 26200224 PMCID: PMC4580624 DOI: 10.1097/rli.0000000000000188] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
During the past decade, ultrasound has expanded medical imaging well beyond the "traditional" radiology setting: a combination of portability, low cost, and ease of use makes ultrasound imaging an indispensable tool for radiologists as well as for other medical professionals who need to obtain imaging diagnosis or guide a therapeutic intervention quickly and efficiently. Ultrasound combines excellent ability for deep penetration into soft tissues with very good spatial resolution, with only a few exceptions (ie, those involving overlying bone or gas). Real-time imaging (up to hundreds and thousands of frames per second) enables guidance of therapeutic procedures and biopsies; characterization of the mechanical properties of the tissues greatly aids with the accuracy of the procedures. The ability of ultrasound to deposit energy locally brings about the potential for localized intervention encompassing the following: tissue ablation, enhancing penetration through the natural barriers to drug delivery in the body and triggering drug release from carrier microparticles and nanoparticles. The use of microbubble contrast agents brings the ability to monitor and quantify tissue perfusion, and microbubble targeting with ligand-decorated microbubbles brings the ability to obtain molecular biomarker information, that is, ultrasound molecular imaging. Overall, ultrasound has become the most widely used imaging modality in modern medicine; it will continue to grow and expand.
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Affiliation(s)
- Alexander L Klibanov
- From the *Cardiovascular Division, Robert M. Berne Cardiovascular Research Center, School of Medicine, and †Department of Biomedical Engineering, University of Virginia, Charlottesville VA
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60
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Tang J, Xi L, Zhou J, Huang H, Zhang T, Carney PR, Jiang H. Noninvasive high-speed photoacoustic tomography of cerebral hemodynamics in awake-moving rats. J Cereb Blood Flow Metab 2015; 35:1224-32. [PMID: 26082016 PMCID: PMC4527999 DOI: 10.1038/jcbfm.2015.138] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 04/10/2015] [Accepted: 05/06/2015] [Indexed: 11/09/2022]
Abstract
We present a noninvasive method of photoacoustic tomography (PAT) for imaging cerebral hemodynamics in awake-moving rats. The wearable PAT (wPAT) system has a size of 15 mm in height and 33 mm in diameter, and a weight of ~8 g (excluding cabling). The wPAT achieved an imaging rate of 3.33 frames/s with a lateral resolution of 243 μm. Animal experiments were designed to show wPAT feasibility for imaging cerebral hemodynamics on awake-moving animals. Results showed that the cerebral oxy-hemoglobin and deoxy-hemoglobin changed significantly in response to hyperoxia; and, after the injection of pentylenetetrazol (PTZ), cerebral blood volume changed faster over time and larger in amplitude for rats in awake-moving state compared with rats under anesthesia. By providing a light-weight, high-resolution technology for in vivo monitoring of cerebral hemodynamics in awake-behaving animals, it will be possible to develop a comprehensive understanding on how activity alters hemodynamics in normal and diseased states.
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Affiliation(s)
- Jianbo Tang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, USA
| | - Lei Xi
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, USA
| | - Junli Zhou
- Department of Pediatrics, University of Florida, Gainesville, Florida, USA
| | - Hua Huang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, USA
| | - Tao Zhang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, USA
| | - Paul R Carney
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, USA
- Department of Pediatrics, University of Florida, Gainesville, Florida, USA
- Department of Neurology, University of Florida, Gainesville, Florida, USA
- Department of Neuroscience, University of Florida, Gainesville, Florida, USA
| | - Huabei Jiang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, USA
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61
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Lin JB, Phillips EH, Riggins TE, Sangha GS, Chakraborty S, Lee JY, Lycke RJ, Hernandez CL, Soepriatna AH, Thorne BRH, Yrineo AA, Goergen CJ. Imaging of small animal peripheral artery disease models: recent advancements and translational potential. Int J Mol Sci 2015; 16:11131-77. [PMID: 25993289 PMCID: PMC4463694 DOI: 10.3390/ijms160511131] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Accepted: 03/10/2015] [Indexed: 12/11/2022] Open
Abstract
Peripheral artery disease (PAD) is a broad disorder encompassing multiple forms of arterial disease outside of the heart. As such, PAD development is a multifactorial process with a variety of manifestations. For example, aneurysms are pathological expansions of an artery that can lead to rupture, while ischemic atherosclerosis reduces blood flow, increasing the risk of claudication, poor wound healing, limb amputation, and stroke. Current PAD treatment is often ineffective or associated with serious risks, largely because these disorders are commonly undiagnosed or misdiagnosed. Active areas of research are focused on detecting and characterizing deleterious arterial changes at early stages using non-invasive imaging strategies, such as ultrasound, as well as emerging technologies like photoacoustic imaging. Earlier disease detection and characterization could improve interventional strategies, leading to better prognosis in PAD patients. While rodents are being used to investigate PAD pathophysiology, imaging of these animal models has been underutilized. This review focuses on structural and molecular information and disease progression revealed by recent imaging efforts of aortic, cerebral, and peripheral vascular disease models in mice, rats, and rabbits. Effective translation to humans involves better understanding of underlying PAD pathophysiology to develop novel therapeutics and apply non-invasive imaging techniques in the clinic.
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Affiliation(s)
- Jenny B Lin
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Evan H Phillips
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Ti'Air E Riggins
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Gurneet S Sangha
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Sreyashi Chakraborty
- School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.
| | - Janice Y Lee
- Psychological Sciences, Purdue University, West Lafayette, IN 47907, USA.
| | - Roy J Lycke
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Clarissa L Hernandez
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Arvin H Soepriatna
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Bradford R H Thorne
- School of Sciences, Neuroscience, Purdue University, West Lafayette, IN 47907, USA.
| | - Alexa A Yrineo
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
| | - Craig J Goergen
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, Room 3025, West Lafayette, IN 47907, USA.
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62
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Edmunds KJ, Gargiulo P. Imaging Approaches in Functional Assessment of Implantable Myogenic Biomaterials and Engineered Muscle Tissue. Eur J Transl Myol 2015; 25:4847. [PMID: 26913149 PMCID: PMC4749010 DOI: 10.4081/ejtm.2015.4847] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 01/21/2015] [Indexed: 12/13/2022] Open
Abstract
The fields of tissue engineering and regenerative medicine utilize implantable biomaterials and engineered tissues to regenerate damaged cells or replace lost tissues. There are distinct challenges in all facets of this research, but functional assessments and monitoring of such complex environments as muscle tissues present the current strategic priority. Many extant methods for addressing these questions result in the destruction or alteration of tissues or cell populations under investigation. Modern advances in non-invasive imaging modalities present opportunities to rethink some of the anachronistic methods, however, their standard employment may not be optimal when considering advancements in myology. New image analysis protocols and/or combinations of established modalities need to be addressed. This review focuses on efficacies and limitations of available imaging modalities to the functional assessment of implantable myogenic biomaterials and engineered muscle tissues.
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Affiliation(s)
- Kyle J. Edmunds
- Institute for Biomedical and Neural Engineering, University of Reykjavík
| | - Paolo Gargiulo
- Institute for Biomedical and Neural Engineering, University of Reykjavík
- University Hospital Landspítali, Reykjavík, Iceland
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63
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Cash KJ, Li C, Xia J, Wang LV, Clark HA. Optical drug monitoring: photoacoustic imaging of nanosensors to monitor therapeutic lithium in vivo. ACS NANO 2015; 9:1692-8. [PMID: 25588028 PMCID: PMC4364417 DOI: 10.1021/nn5064858] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Personalized medicine could revolutionize how primary care physicians treat chronic disease and how researchers study fundamental biological questions. To realize this goal, we need to develop more robust, modular tools and imaging approaches for in vivo monitoring of analytes. In this report, we demonstrate that synthetic nanosensors can measure physiologic parameters with photoacoustic contrast, and we apply that platform to continuously track lithium levels in vivo. Photoacoustic imaging achieves imaging depths that are unattainable with fluorescence or multiphoton microscopy. We validated the photoacoustic results that illustrate the superior imaging depth and quality of photoacoustic imaging with optical measurements. This powerful combination of techniques will unlock the ability to measure analyte changes in deep tissue and will open up photoacoustic imaging as a diagnostic tool for continuous physiological tracking of a wide range of analytes.
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Affiliation(s)
- Kevin J. Cash
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Chiye Li
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Jun Xia
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Lihong V. Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Heather A. Clark
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
- Corresponding Author Correspondence to:
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64
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Li G, Xia J, Wang K, Maslov K, Anastasio MA, Wang LV. Tripling the detection view of high-frequency linear-array-based photoacoustic computed tomography by using two planar acoustic reflectors. Quant Imaging Med Surg 2015; 5:57-62. [PMID: 25694954 DOI: 10.3978/j.issn.2223-4292.2014.11.09] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 10/19/2014] [Indexed: 11/14/2022]
Abstract
BACKGROUND Linear-array-based photoacoustic computed tomography (PACT) suffers from a limited view. Circular scanning does increase the detection view angle but is time-consuming. Therefore, it is desirable to increase the detection view angle of linear-array-based PACT without sacrificing imaging speed. METHODS Two planar acoustic reflectors placed at 120 degrees to each other were added to a linear-array-based PACT system. Each reflector redirects originally undetectable photoacoustic waves back to the transducer array elements, and together they triple the original detection view angle of the PACT system. RESULTS Adding two reflectors increased the detection view angle from 80 to 240 degrees. As a comparison, a single-reflector PACT has a detection view angle of only 160 degrees. A leaf skeleton phantom with a rich vascular network was imaged with the double-reflector PACT, and most of its features were recovered. CONCLUSIONS The two acoustic reflectors triple the detection view angle of a linear-array-based PACT without compromising the original imaging speed. This nearly full-view detection capability produces higher-quality images than single-reflector PACT or conventional PACT without reflectors.
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Affiliation(s)
- Guo Li
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
| | - Jun Xia
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
| | - Kun Wang
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
| | - Konstantin Maslov
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
| | - Mark A Anastasio
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
| | - Lihong V Wang
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
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Kim J, Lee D, Jung U, Kim C. Photoacoustic imaging platforms for multimodal imaging. Ultrasonography 2015; 34:88-97. [PMID: 25754364 PMCID: PMC4372714 DOI: 10.14366/usg.14062] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/09/2015] [Accepted: 02/16/2015] [Indexed: 11/22/2022] Open
Abstract
Photoacoustic (PA) imaging is a hybrid biomedical imaging method that exploits both acoustical Epub ahead of print and optical properties and can provide both functional and structural information. Therefore, PA imaging can complement other imaging methods, such as ultrasound imaging, fluorescence imaging, optical coherence tomography, and multi-photon microscopy. This article reviews techniques that integrate PA with the above imaging methods and describes their applications.
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Affiliation(s)
- Jeesu Kim
- Departments of Electrical Engineering, Pohang University of Science and Technology, Pohang, Korea
| | - Donghyun Lee
- Departments of Creative IT Engineering, Pohang University of Science and Technology, Pohang, Korea
| | - Unsang Jung
- Departments of Future IT Innovation Laboratory, Pohang University of Science and Technology, Pohang, Korea
| | - Chulhong Kim
- Departments of Electrical Engineering, Pohang University of Science and Technology, Pohang, Korea ; Departments of Creative IT Engineering, Pohang University of Science and Technology, Pohang, Korea
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66
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Lin L, Xia J, Wong TTW, Li L, Wang LV. In vivo deep brain imaging of rats using oral-cavity illuminated photoacoustic computed tomography. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:016019. [PMID: 25611865 PMCID: PMC4302266 DOI: 10.1117/1.jbo.20.1.016019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/06/2015] [Indexed: 05/04/2023]
Abstract
Using internal illumination with an optical fiber in the oral cavity, we demonstrate, for the first time, photoacoustic computed tomography (PACT) of the deep brain of rats in vivo. The experiment was performed on a full-ring-array PACT system, with the capability of providing high-speed cross-sectional imaging of the brain. Compared with external illumination through the cranial skull, internal illumination delivers more light to the base of the brain. Consequently, in vivo photoacoustic images clearly reveal deep brain structures such as the hypothalamus, brain stem, and cerebral medulla.
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Affiliation(s)
- Li Lin
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, St. Louis, Missouri 63130, United States
| | - Jun Xia
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, St. Louis, Missouri 63130, United States
- The State University of New York, University at Buffalo, Department of Biomedical Engineering, Buffalo, New York 14260, United States
| | - Terence T. W. Wong
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, St. Louis, Missouri 63130, United States
| | - Lei Li
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, St. Louis, Missouri 63130, United States
| | - Lihong V. Wang
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, St. Louis, Missouri 63130, United States
- Address all correspondence to: Lihong V. Wang, E-mail:
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67
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Lutzweiler C, Deán-Ben XL, Razansky D. Expediting model-based optoacoustic reconstructions with tomographic symmetries. Med Phys 2014; 41:013302. [PMID: 24387532 DOI: 10.1118/1.4846055] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Image quantification in optoacoustic tomography implies the use of accurate forward models of excitation, propagation, and detection of optoacoustic signals while inversions with high spatial resolution usually involve very large matrices, leading to unreasonably long computation times. The development of fast and memory efficient model-based approaches represents then an important challenge to advance on the quantitative and dynamic imaging capabilities of tomographic optoacoustic imaging. METHODS Herein, a method for simplification and acceleration of model-based inversions, relying on inherent symmetries present in common tomographic acquisition geometries, has been introduced. The method is showcased for the case of cylindrical symmetries by using polar image discretization of the time-domain optoacoustic forward model combined with efficient storage and inversion strategies. RESULTS The suggested methodology is shown to render fast and accurate model-based inversions in both numerical simulations and post mortem small animal experiments. In case of a full-view detection scheme, the memory requirements are reduced by one order of magnitude while high-resolution reconstructions are achieved at video rate. CONCLUSIONS By considering the rotational symmetry present in many tomographic optoacoustic imaging systems, the proposed methodology allows exploiting the advantages of model-based algorithms with feasible computational requirements and fast reconstruction times, so that its convenience and general applicability in optoacoustic imaging systems with tomographic symmetries is anticipated.
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Affiliation(s)
- Christian Lutzweiler
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstädter Landstraβe 1, 85764 Neuherberg, Germany and Faculty of Medicine, Technical University of Munich, Ismaninger Straβe 22, 81675 Munich, Germany
| | - Xosé Luís Deán-Ben
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstädter Landstraβe 1, 85764 Neuherberg, Germany and Faculty of Medicine, Technical University of Munich, Ismaninger Straβe 22, 81675 Munich, Germany
| | - Daniel Razansky
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstädter Landstraβe 1, 85764 Neuherberg, Germany and Faculty of Medicine, Technical University of Munich, Ismaninger Straβe 22, 81675 Munich, Germany
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Jarrett CW, Caskey CF, Gore JC. Detection of a novel mechanism of acousto-optic modulation of incoherent light. PLoS One 2014; 9:e104268. [PMID: 25105880 PMCID: PMC4126715 DOI: 10.1371/journal.pone.0104268] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 07/07/2014] [Indexed: 11/20/2022] Open
Abstract
A novel form of acoustic modulation of light from an incoherent source has been detected in water as well as in turbid media. We demonstrate that patterns of modulated light intensity appear to propagate as the optical shadow of the density variations caused by ultrasound within an illuminated ultrasonic focal zone. This pattern differs from previous reports of acousto-optical interactions that produce diffraction effects that rely on phase shifts and changes in light directions caused by the acoustic modulation. Moreover, previous studies of acousto-optic interactions have mainly reported the effects of sound on coherent light sources via photon tagging, and/or the production of diffraction phenomena from phase effects that give rise to discrete sidebands. We aimed to assess whether the effects of ultrasound modulation of the intensity of light from an incoherent light source could be detected directly, and how the acoustically modulated (AOM) light signal depended on experimental parameters. Our observations suggest that ultrasound at moderate intensities can induce sufficiently large density variations within a uniform medium to cause measurable modulation of the intensity of an incoherent light source by absorption. Light passing through a region of high intensity ultrasound then produces a pattern that is the projection of the density variations within the region of their interaction. The patterns exhibit distinct maxima and minima that are observed at locations much different from those predicted by Raman-Nath, Bragg, or other diffraction theory. The observed patterns scaled appropriately with the geometrical magnification and sound wavelength. We conclude that these observed patterns are simple projections of the ultrasound induced density changes which cause spatial and temporal variations of the optical absorption within the illuminated sound field. These effects potentially provide a novel method for visualizing sound fields and may assist the interpretation of other hybrid imaging methods.
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Affiliation(s)
- Christopher W. Jarrett
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, United States of America
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- * E-mail:
| | - Charles F. Caskey
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States of America
| | - John C. Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, United States of America
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States of America
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Cho Y, Chang CC, Yu J, Jeon M, Kim C, Wang LV, Zou J. Handheld photoacoustic tomography probe built using optical-fiber parallel acoustic delay lines. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:086007. [PMID: 25104413 PMCID: PMC4407766 DOI: 10.1117/1.jbo.19.8.086007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 06/30/2014] [Accepted: 07/14/2014] [Indexed: 05/19/2023]
Abstract
The development of the first miniaturized parallel acoustic delay line (PADL) probe for handheld photoacoustic tomography (PAT) is reported. Using fused-silica optical fibers with low acoustic attenuation, we constructed two arrays of eight PADLs. Precision laser micromachining was conducted to produce robust and accurate mechanical support and alignment structures for the PADLs, with minimal acoustic distortion and interchannel coupling. The 16 optical-fiber PADLs, each with a different time delay, were arranged to form one input port and two output ports. A handheld PADL probe was constructed using two single-element transducers and two data acquisition channels (equal to a channel reduction ratio of 8∶1). Photoacoustic (PA) images of a black-ink target embedded in an optically scattering phantom were successfully acquired. After traveling through the PADLs, the eight channels of differently time-delayed PA signals reached each single-element ultrasonic transducer in a designated nonoverlapping time series, allowing clear signal separation for PA image reconstruction. Our results show that the PADL technique and the handheld probe can potentially enable real-time PAT, while significantly reducing the complexity and cost of the ultrasound receiver system.
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Affiliation(s)
- Young Cho
- Texas A&M University, Department of Electrical and Computer Engineering, College Station, Texas 77843, United States
| | - Cheng-Chung Chang
- Texas A&M University, Department of Electrical and Computer Engineering, College Station, Texas 77843, United States
| | - Jaesok Yu
- University of Pittsburgh, Department of Bioengineering, Pittsburgh, Pennsylvania 15260, United States
| | - Mansik Jeon
- Pohang University of Science and Technology, Department of Creative IT Engineering, Pohang 790-784, Republic of Korea
| | - Chulhong Kim
- Pohang University of Science and Technology, Department of Creative IT Engineering, Pohang 790-784, Republic of Korea
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130, United States
| | - Jun Zou
- Texas A&M University, Department of Electrical and Computer Engineering, College Station, Texas 77843, United States
- Address all correspondence to: Jun Zou, E-mail:
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Erkol H, Aytac-Kipergil E, Unlu MB. Photoacoustic radiation force on a microbubble. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:023001. [PMID: 25215814 DOI: 10.1103/physreve.90.023001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Indexed: 06/03/2023]
Abstract
We investigate the radiation force on a microbubble due to the photoacoustic wave which is generated by using a pulsed laser. In particular, we focus on the dependence of pulsed laser parameters on the radiation force. In order to do so, we first obtain a new and comprehensive analytical solution to the photoacoustic wave equation based on the Fourier transform for various absorption profiles. Then, we write an expression of the radiation force containing explicit laser parameters, pulse duration, and beamwidth of the laser. Furthermore, we calculate the primary radiation force acting on a microbubble. We show that laser parameters and the position of the microbubble relative to a photoacoustic source have a considerable effect on the primary radiation force. By means of recent developments in laser technologies that render tunability of pulse duration and repetition frequency possible, an adjustable radiation force can be applied to microbubbles. High spatial control of applied force is ensured on account of smaller focal spots achievable by focused optics. In this context, conventional piezoelectric acoustic source applications could be surpassed. In addition, it is possible to increase the radiation force by making source wavelength with the absorption peak of absorber concurrent. The application of photoacoustic radiation force can open a cache of opportunities such as manipulation of microbubbles used as contrast agents and as carrier vehicles for drugs and genes with a desired force along with in vivo applications.
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Affiliation(s)
- Hakan Erkol
- Department of Physics, Bogazici University, Bebek, 34342 Istanbul, Turkey
| | | | - Mehmet Burcin Unlu
- Department of Physics, Bogazici University, Bebek, 34342 Istanbul, Turkey
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71
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Abstract
Photoacoustic imaging (PAI) of biological tissue has seen immense growth in the past decade, providing unprecedented spatial resolution and functional information at depths in the optical diffusive regime. PAI uniquely combines the advantages of optical excitation and those of acoustic detection. The hybrid imaging modality features high sensitivity to optical absorption and wide scalability of spatial resolution with the desired imaging depth. Here we first summarize the fundamental principles underpinning the technology, then highlight its practical implementation, and finally discuss recent advances toward clinical translation.
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Affiliation(s)
- Lihong V. Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis
| | - Liang Gao
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis
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72
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Wang K, Xia J, Li C, Wang LV, Anastasio MA. Fast spatiotemporal image reconstruction based on low-rank matrix estimation for dynamic photoacoustic computed tomography. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:056007. [PMID: 24817620 PMCID: PMC4046831 DOI: 10.1117/1.jbo.19.5.056007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 03/21/2014] [Indexed: 05/06/2023]
Abstract
In order to monitor dynamic physiological events in near-real time, a variety of photoacoustic computed tomography (PACT) systems have been developed that can rapidly acquire data. Previously reported studies of dynamic PACT have employed conventional static methods to reconstruct a temporally ordered sequence of images on a frame-by-frame basis. Frame-by-frame image reconstruction (FBFIR) methods fail to exploit correlations between data frames and are known to be statistically and computationally suboptimal. In this study, a low-rank matrix estimation-based spatiotemporal image reconstruction (LRME-STIR) method is investigated for dynamic PACT applications. The LRME-STIR method is based on the observation that, in many PACT applications, the number of frames is much greater than the rank of the ideal noiseless data matrix. Using both computer-simulated and experimentally measured photoacoustic data, the performance of the LRME-STIR method is compared with that of conventional FBFIR method followed by image-domain filtering. The results demonstrate that the LRME-STIR method is not only computationally more efficient but also produces more accurate dynamic PACT images than a conventional FBFIR method followed by image-domain filtering.
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Affiliation(s)
- Kun Wang
- Washington University in St.
Louis, Department of Biomedical Engineering, St. Louis,
Missouri, 63130
| | - Jun Xia
- Washington University in St.
Louis, Department of Biomedical Engineering, St. Louis,
Missouri, 63130
| | - Changhui Li
- Peking University,
Department of Biomedical Engineering, Beijing 100871,
China
| | - Lihong V. Wang
- Washington University in St.
Louis, Department of Biomedical Engineering, St. Louis,
Missouri, 63130
| | - Mark A. Anastasio
- Washington University in St.
Louis, Department of Biomedical Engineering, St. Louis,
Missouri, 63130
- Address all correspondence to: Mark A. Anastasio,
E-mail:
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73
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Abstract
With the wide use of small animals for biomedical studies, in vivo small-animal whole-body imaging plays an increasingly important role. Photoacoustic tomography (PAT) is an emerging whole-body imaging modality that shows great potential for preclinical research. As a hybrid technique, PAT is based on the acoustic detection of optical absorption from either endogenous tissue chromophores, such as oxyhemoglobin and deoxyhemoglobin, or exogenous contrast agents. Because ultrasound scatters much less than light in tissue, PAT generates high-resolution images in both the optical ballistic and diffusive regimes. Using near-infrared light, which has relatively low blood absorption, PAT can image through the whole body of small animals with acoustically defined spatial resolution. Anatomical and vascular structures are imaged with endogenous hemoglobin contrast, while functional and molecular images are enabled by the wide choice of exogenous optical contrasts. This paper reviews the rapidly growing field of small-animal whole-body PAT and highlights studies done in the past decade.
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Affiliation(s)
- Jun Xia
- J. Xia and L.V. Wang are with the Optical Imaging Lab, Department of Biomedical Engineering, Washington University in St. Louis ( and )
| | - Lihong V. Wang
- J. Xia and L.V. Wang are with the Optical Imaging Lab, Department of Biomedical Engineering, Washington University in St. Louis ( and )
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74
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Buehler A, Deán-Ben XL, Razansky D, Ntziachristos V. Volumetric optoacoustic imaging with multi-bandwidth deconvolution. IEEE TRANSACTIONS ON MEDICAL IMAGING 2014; 33:814-21. [PMID: 24058023 DOI: 10.1109/tmi.2013.2282173] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Optoacoustic (photoacoustic) imaging based on cylindrically focused 1-D transducer arrays comes with powerful characteristics in visualizing optical contrast. Parallel reading of multiple detectors arranged around a tissue cross section enables capturing data for generating images of this plane within micro-seconds. Dedicated small animals scanners and handheld systems using 1-D cylindrically focused ultrasound transducer arrays have demonstrated real-time cross-sectional imaging and high in-plane resolution. Yet, the resolution achieved along the axis perpendicular to the focal plane, i.e., the elevation resolution, is determined by the focusing capacities of the detector and is typically lower than the in-plane resolution. Herein, we investigated whether deconvolution of the sensitivity field of the transducer could lead to tangible image improvements. We showcase the findings on experimental measurements from phantoms and animals and discuss the features and the limitations of the approach in improving resolution along the elevation dimension.
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75
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Krumholz A, Shcherbakova DM, Xia J, Wang LV, Verkhusha VV. Multicontrast photoacoustic in vivo imaging using near-infrared fluorescent proteins. Sci Rep 2014; 4:3939. [PMID: 24487319 PMCID: PMC3909896 DOI: 10.1038/srep03939] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 01/15/2014] [Indexed: 11/15/2022] Open
Abstract
Non-invasive imaging of biological processes in vivo is invaluable in advancing biology. Photoacoustic tomography is a scalable imaging technique that provides higher resolution at greater depths in tissue than achievable by purely optical methods. Here we report the application of two spectrally distinct near-infrared fluorescent proteins, iRFP670 and iRFP720, engineered from bacterial phytochromes, as photoacoustic contrast agents. iRFPs provide tissue-specific contrast without the need for delivery of any additional substances. Compared to conventional GFP-like red-shifted fluorescent proteins, iRFP670 and iRFP720 demonstrate stronger photoacoustic signals at longer wavelengths, and can be spectrally resolved from each other and hemoglobin. We simultaneously visualized two differently labeled tumors, one with iRFP670 and the other with iRFP720, as well as blood vessels. We acquired images of a mouse as 2D sections of a whole animal, and as localized 3D volumetric images with high contrast and sub-millimeter resolution at depths up to 8 mm. Our results suggest iRFPs are genetically-encoded probes of choice for simultaneous photoacoustic imaging of several tissues or processes in vivo.
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Affiliation(s)
- Arie Krumholz
- Department of Biomedical Engineering, Optical Imaging Laboratory, Washington University in St. Louis, St. Louis, MO 63130, USA
- These authors contributed equally to this work
| | - Daria M. Shcherbakova
- Department of Anatomy and Structural Biology, and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- These authors contributed equally to this work
| | - Jun Xia
- Department of Biomedical Engineering, Optical Imaging Laboratory, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Lihong V. Wang
- Department of Biomedical Engineering, Optical Imaging Laboratory, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Vladislav V. Verkhusha
- Department of Anatomy and Structural Biology, and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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76
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Paltauf G, Nuster R. Artifact removal in photoacoustic section imaging by combining an integrating cylindrical detector with model-based reconstruction. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:026014. [PMID: 24566958 DOI: 10.1117/1.jbo.19.2.026014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 01/15/2014] [Indexed: 05/18/2023]
Abstract
Photoacoustic section imaging reveals optically absorbing structures within a thin slice of an object. It requires measuring acoustic waves excited by absorption of short laser pulses with a cylindrical acoustic lens detector rotating around the object. Owing to the finite detector size and its limited depth of focus, various artifacts arise, seen as distortions within the imaging slice and cross-talk from neighboring areas of the object. The presented solution aims at avoiding these artifacts by a special design of the sensor and by use of a model-based reconstruction algorithm that improves section images by incorporating information from neighboring sections. The integrating property of the cylindrical detector, which exceeds in direction of the cylinder axis the size of the imaged object, avoids the lateral blurring that normally results from the finite width of a small detector. Applying a maximum likelihood reconstruction method for the inversion of the imaging system matrix to the temporal pressure signals yields line projections of the initial energy distribution, from which section images are obtained by applying the inverse Radon transform. By using data from few sections, a significant reduction of artifacts related to the imperfections of the sensor is demonstrated both in simulations and in phantom experiments.
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77
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Rosenthal A, Ntziachristos V, Razansky D. Acoustic Inversion in Optoacoustic Tomography: A Review. Curr Med Imaging 2014; 9:318-336. [PMID: 24772060 PMCID: PMC3996917 DOI: 10.2174/15734056113096660006] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 06/19/2013] [Accepted: 06/24/2013] [Indexed: 01/01/2023]
Abstract
Optoacoustic tomography enables volumetric imaging with optical contrast in biological tissue at depths beyond
the optical mean free path by the use of optical excitation and acoustic detection. The hybrid nature of optoacoustic
tomography gives rise to two distinct inverse problems: The optical inverse problem, related to the propagation of the excitation
light in tissue, and the acoustic inverse problem, which deals with the propagation and detection of the generated
acoustic waves. Since the two inverse problems have different physical underpinnings and are governed by different types
of equations, they are often treated independently as unrelated problems. From an imaging standpoint, the acoustic inverse
problem relates to forming an image from the measured acoustic data, whereas the optical inverse problem relates to
quantifying the formed image. This review focuses on the acoustic aspects of optoacoustic tomography, specifically
acoustic reconstruction algorithms and imaging-system practicalities. As these two aspects are intimately linked, and no
silver bullet exists in the path towards high-performance imaging, we adopt a holistic approach in our review and discuss
the many links between the two aspects. Four classes of reconstruction algorithms are reviewed: time-domain (so called
back-projection) formulae, frequency-domain formulae, time-reversal algorithms, and model-based algorithms. These algorithms
are discussed in the context of the various acoustic detectors and detection surfaces which are commonly used in
experimental studies. We further discuss the effects of non-ideal imaging scenarios on the quality of reconstruction and
review methods that can mitigate these effects. Namely, we consider the cases of finite detector aperture, limited-view
tomography, spatial under-sampling of the acoustic signals, and acoustic heterogeneities and losses.
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Affiliation(s)
- Amir Rosenthal
- Institute for Biological and Medical Imaging, Helmholtz Zentrum München, Ingoldstädter Landstraße 1, Neuherberg 85764, Germay; ; Chair for Biological Imaging, Technische Universität München, Ismaninger Str. 22, München 81675, Germany
| | - Vasilis Ntziachristos
- Institute for Biological and Medical Imaging, Helmholtz Zentrum München, Ingoldstädter Landstraße 1, Neuherberg 85764, Germay; ; Chair for Biological Imaging, Technische Universität München, Ismaninger Str. 22, München 81675, Germany
| | - Daniel Razansky
- Institute for Biological and Medical Imaging, Helmholtz Zentrum München, Ingoldstädter Landstraße 1, Neuherberg 85764, Germay; ; Chair for Biological Imaging, Technische Universität München, Ismaninger Str. 22, München 81675, Germany
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Nasiriavanaki M, Xia J, Wan H, Bauer AQ, Culver JP, Wang LV. High-resolution photoacoustic tomography of resting-state functional connectivity in the mouse brain. Proc Natl Acad Sci U S A 2014; 111:21-6. [PMID: 24367107 PMCID: PMC3890828 DOI: 10.1073/pnas.1311868111] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The increasing use of mouse models for human brain disease studies presents an emerging need for a new functional imaging modality. Using optical excitation and acoustic detection, we developed a functional connectivity photoacoustic tomography system, which allows noninvasive imaging of resting-state functional connectivity in the mouse brain, with a large field of view and a high spatial resolution. Bilateral correlations were observed in eight functional regions, including the olfactory bulb, limbic, parietal, somatosensory, retrosplenial, visual, motor, and temporal regions, as well as in several subregions. The borders and locations of these regions agreed well with the Paxinos mouse brain atlas. By subjecting the mouse to alternating hyperoxic and hypoxic conditions, strong and weak functional connectivities were observed, respectively. In addition to connectivity images, vascular images were simultaneously acquired. These studies show that functional connectivity photoacoustic tomography is a promising, noninvasive technique for functional imaging of the mouse brain.
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Affiliation(s)
| | - Jun Xia
- Optical Imaging Laboratory, Department of Biomedical Engineering and
| | - Hanlin Wan
- Optical Imaging Laboratory, Department of Biomedical Engineering and
| | - Adam Quentin Bauer
- Department of Radiology, Washington University in St. Louis, St. Louis, MO 63130
| | - Joseph P. Culver
- Department of Radiology, Washington University in St. Louis, St. Louis, MO 63130
| | - Lihong V. Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering and
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Xia J, Chen W, Maslov K, Anastasio MA, Wang LV. Retrospective respiration-gated whole-body photoacoustic computed tomography of mice. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:16003. [PMID: 24395586 PMCID: PMC3881607 DOI: 10.1117/1.jbo.19.1.016003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Revised: 11/20/2013] [Accepted: 11/27/2013] [Indexed: 05/23/2023]
Abstract
Photoacoustic tomography (PAT) is an emerging technique that has a great potential for preclinical whole-body imaging. To date, most whole-body PAT systems require multiple laser shots to generate one cross-sectional image, yielding a frame rate of <1 Hz. Because a mouse breathes at up to 3 Hz, without proper gating mechanisms, acquired images are susceptible to motion artifacts. Here, we introduce, for the first time to our knowledge, retrospective respiratory gating for whole-body photoacoustic computed tomography. This new method involves simultaneous capturing of the animal's respiratory waveform during photoacoustic data acquisition. The recorded photoacoustic signals are sorted and clustered according to the respiratory phase, and an image of the animal at each respiratory phase is reconstructed subsequently from the corresponding cluster. The new method was tested in a ring-shaped confocal photoacoustic computed tomography system with a hardware-limited frame rate of 0.625 Hz. After respiratory gating, we observed sharper vascular and anatomical images at different positions of the animal body. The entire breathing cycle can also be visualized at 20 frames/cycle.
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Affiliation(s)
- Jun Xia
- Washington University in St. Louis, Optical Imaging Lab, Department of Biomedical Engineering, One Brookings Drive, Saint Louis, Missouri 63130
| | - Wanyi Chen
- Washington University in St. Louis, Optical Imaging Lab, Department of Biomedical Engineering, One Brookings Drive, Saint Louis, Missouri 63130
| | - Konstantin Maslov
- Washington University in St. Louis, Optical Imaging Lab, Department of Biomedical Engineering, One Brookings Drive, Saint Louis, Missouri 63130
| | - Mark A. Anastasio
- Washington University in St. Louis, Optical Imaging Lab, Department of Biomedical Engineering, One Brookings Drive, Saint Louis, Missouri 63130
| | - Lihong V. Wang
- Washington University in St. Louis, Optical Imaging Lab, Department of Biomedical Engineering, One Brookings Drive, Saint Louis, Missouri 63130
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80
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Xia J, Li G, Wang L, Nasiriavanaki M, Maslov K, Engelbach JA, Garbow JR, Wang LV. Wide-field two-dimensional multifocal optical-resolution photoacoustic-computed microscopy. OPTICS LETTERS 2013; 38:5236-9. [PMID: 24322226 PMCID: PMC3928040 DOI: 10.1364/ol.38.005236] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Optical-resolution photoacoustic microscopy (OR-PAM) is an emerging technique that directly images optical absorption in tissue at high spatial resolution. To date, the majority of OR-PAM systems are based on single-focused optical excitation and ultrasonic detection, limiting the wide-field imaging speed. While 1D multifocal OR-PAM (1D-MFOR-PAM) has been developed, the potential of microlens and transducer arrays has not been fully realized. Here we present the development of 2D multifocal optical-resolution photoacoustic-computed microscopy (2D-MFOR-PACM), using a 2D microlens array and a full-ring ultrasonic transducer array. The 10 mm×10 mm microlens array generates 1800 optical foci within the focal plane of the 512-element transducer array, and raster scanning the microlens array yields optical-resolution photoacoustic images. The system has improved the in-plane resolution of a full-ring transducer array from ≥100 to 29 μm and achieved an imaging time of 36 s over a 10 mm×10 mm field of view. In comparison, the 1D-MFOR-PAM would take more than 4 min to image over the same field of view. The imaging capability of the system was demonstrated on phantoms and animals both ex vivo and in vivo.
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Affiliation(s)
- Jun Xia
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Saint Louis, Missouri 63130, USA
| | - Guo Li
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Saint Louis, Missouri 63130, USA
| | - Lidai Wang
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Saint Louis, Missouri 63130, USA
| | - Mohammadreza Nasiriavanaki
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Saint Louis, Missouri 63130, USA
| | - Konstantin Maslov
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Saint Louis, Missouri 63130, USA
| | - John A. Engelbach
- Department of Radiology, Washington University in St. Louis, 660 S. Euclid Ave, Saint Louis, Missouri 63110, USA
| | - Joel R. Garbow
- Department of Radiology, Washington University in St. Louis, 660 S. Euclid Ave, Saint Louis, Missouri 63110, USA
| | - Lihong V. Wang
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Saint Louis, Missouri 63130, USA
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81
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Dean-Ben XL, Ozbek A, Razansky D. Volumetric real-time tracking of peripheral human vasculature with GPU-accelerated three-dimensional optoacoustic tomography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:2050-5. [PMID: 23846468 DOI: 10.1109/tmi.2013.2272079] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Optoacoustic tomography provides a unique possibility for ultra-high-speed 3-D imaging by acquiring complete volumetric datasets from interrogation of tissue by a single nanosecond-duration laser pulse. Yet, similarly to ultrasound, optoacoustics is a time-resolved imaging method, thus, fast 3-D imaging implies real-time acquisition and processing of high speed data from hundreds of detectors simultaneously, which presents significant technological challenges. Herein we present a highly efficient graphical processing unit (GPU) framework for real-time reconstruction and visualization of 3-D tomographic optoacoustic data. By utilizing a newly developed 3-D optoacoustic scanner, which simultaneously acquires signals with a handheld 256-element spherical ultrasonic array system, we further demonstrate tracking of deep tissue human vasculature rendered at a rate of 10 volumetric frames per second. The flexibility provided by the handheld hardware design, combined with the real-time operation, makes the developed platform highly usable for both clinical imaging practice and small animal research applications.
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82
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Wang Y, Xia J, Wang LV. Deep-tissue photoacoustic tomography of Förster resonance energy transfer. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:101316. [PMID: 23884608 PMCID: PMC3719951 DOI: 10.1117/1.jbo.18.10.101316] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 07/01/2013] [Accepted: 07/03/2013] [Indexed: 05/20/2023]
Abstract
Förster resonance energy transfer (FRET) is a distance-dependent process that transfers excited state energy from a donor molecule to an acceptor molecule without the emission of a photon. The FRET rate is determined by the proximity between the donor and the acceptor molecules; it becomes significant only when the proximity is within several nanometers. Therefore, FRET has been applied to visualize interactions and conformational changes of biomolecules, such as proteins, lipids, and nucleic acids that cannot be resolved by optical microscopy. Here, we report photoacoustic tomography of FRET efficiency at a 1-cm depth in chicken breast tissue, whereas conventional high-resolution fluorescence imaging is limited to <0.1 cm. Photoacoustic tomography is expected to facilitate the examination of FRET phenomena in living organisms.
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Affiliation(s)
- Yu Wang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, 1 Brookings Dr., St. Louis, Missouri 63130
| | - Jun Xia
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, 1 Brookings Dr., St. Louis, Missouri 63130
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, 1 Brookings Dr., St. Louis, Missouri 63130
- Address all correspondence to: Lihong V. Wang, Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, 1 Brookings Dr., St. Louis, Missouri 63130. Tel: (314) 935-6152; Fax: (314) 935-7448; E-mail:
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83
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Xia W, Piras D, van Hespen JCG, van Veldhoven S, Prins C, van Leeuwen TG, Steenbergen W, Manohar S. An optimized ultrasound detector for photoacoustic breast tomography. Med Phys 2013; 40:032901. [PMID: 23464340 DOI: 10.1118/1.4792462] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Photoacoustic imaging has proven to be able to detect vascularization-driven optical absorption contrast associated with tumors. In order to detect breast tumors located a few centimeter deep in tissue, a sensitive ultrasound detector is of crucial importance for photoacoustic mammography. Further, because the expected photoacoustic frequency bandwidth (a few MHz to tens of kHz) is inversely proportional to the dimensions of light absorbing structures (0.5-10+ mm), proper choices of materials and their geometries and proper considerations in design have to be made to implement optimal photoacoustic detectors. In this study, we design and evaluate a specialized ultrasound detector for photoacoustic mammography. METHODS Based on the required detector sensitivity and its frequency response, a selection of active material and matching layers and their geometries is made leading to functional detector models. By iteration between simulation of detector performances, fabrication and experimental characterization of functional models an optimized implementation is made and evaluated. For computer simulation, we use 1D Krimholtz-Leedom-Matthaei and 3D finite-element based models. RESULTS The experimental results of the designed first and second functional detectors matched with the simulations. In subsequent bare piezoelectric samples the effect of lateral resonances was addressed and their influence minimized by subdicing the samples. Consequently, using simulations, a final optimized detector was designed, with a center frequency of 1 MHz and a -6 dB bandwidth of 0.4-1.25 MHz (fractional bandwidth of ~80%). The minimum detectable pressure was measured to be 0.5 Pa. CONCLUSIONS A single-element, large-aperture, sensitive, and broadband detector is designed and developed for photoacoustic tomography of the breast. The detector should be capable of detecting vascularized tumors with 1-2 mm resolution. The minimum detectable pressure is 0.5 Pa, which will facilitate deeper imaging compared to the current systems. Further improvements by proper electrical grounding and shielding and implementation of this design into an arrayed detector will pave the way for clinical applications of photoacoustic mammography.
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Affiliation(s)
- Wenfeng Xia
- Biomedical Photonic Imaging Group, Mira Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
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84
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Appel AA, Anastasio MA, Larson JC, Brey EM. Imaging challenges in biomaterials and tissue engineering. Biomaterials 2013; 34:6615-30. [PMID: 23768903 PMCID: PMC3799904 DOI: 10.1016/j.biomaterials.2013.05.033] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 05/18/2013] [Indexed: 12/11/2022]
Abstract
Biomaterials are employed in the fields of tissue engineering and regenerative medicine (TERM) in order to enhance the regeneration or replacement of tissue function and/or structure. The unique environments resulting from the presence of biomaterials, cells, and tissues result in distinct challenges in regards to monitoring and assessing the results of these interventions. Imaging technologies for three-dimensional (3D) analysis have been identified as a strategic priority in TERM research. Traditionally, histological and immunohistochemical techniques have been used to evaluate engineered tissues. However, these methods do not allow for an accurate volume assessment, are invasive, and do not provide information on functional status. Imaging techniques are needed that enable non-destructive, longitudinal, quantitative, and three-dimensional analysis of TERM strategies. This review focuses on evaluating the application of available imaging modalities for assessment of biomaterials and tissue in TERM applications. Included is a discussion of limitations of these techniques and identification of areas for further development.
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Affiliation(s)
- Alyssa A. Appel
- Department of Biomedical Engineering, Illinois Institute of Technology, 3255 South Dearborn St, Chicago, IL 60616, USA
- Research Service, Hines Veterans Administration Hospital, Hines, IL, USA
| | - Mark A. Anastasio
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Jeffery C. Larson
- Department of Biomedical Engineering, Illinois Institute of Technology, 3255 South Dearborn St, Chicago, IL 60616, USA
- Research Service, Hines Veterans Administration Hospital, Hines, IL, USA
| | - Eric M. Brey
- Department of Biomedical Engineering, Illinois Institute of Technology, 3255 South Dearborn St, Chicago, IL 60616, USA
- Research Service, Hines Veterans Administration Hospital, Hines, IL, USA
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85
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Xia J, Huang C, Maslov K, Anastasio MA, Wang LV. Enhancement of photoacoustic tomography by ultrasonic computed tomography based on optical excitation of elements of a full-ring transducer array. OPTICS LETTERS 2013; 38:3140-3. [PMID: 24104670 PMCID: PMC3884569 DOI: 10.1364/ol.38.003140] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Photoacoustic computed tomography (PACT) is a hybrid technique that combines optical excitation and ultrasonic detection to provide high-resolution images in deep tissues. In the image reconstruction, a constant speed of sound (SOS) is normally assumed. This assumption, however, is often not strictly satisfied in deep tissue imaging, due to acoustic heterogeneities within the object and between the object and the coupling medium. If these heterogeneities are not accounted for, they will cause distortions and artifacts in the reconstructed images. In this Letter, we incorporated ultrasonic computed tomography (USCT), which measures the SOS distribution within the object, into our full-ring array PACT system. Without the need for ultrasonic transmitting electronics, USCT was performed using the same laser beam as for PACT measurement. By scanning the laser beam on the array surface, we can sequentially fire different elements. As a first demonstration of the system, we studied the effect of acoustic heterogeneities on photoacoustic vascular imaging. We verified that constant SOS is a reasonable approximation when the SOS variation is small. When the variation is large, distortion will be observed in the periphery of the object, especially in the tangential direction.
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86
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Xia J, Danielli A, Liu Y, Wang L, Maslov K, Wang LV. Calibration-free quantification of absolute oxygen saturation based on the dynamics of photoacoustic signals. OPTICS LETTERS 2013; 38:2800-3. [PMID: 23903146 PMCID: PMC3884570 DOI: 10.1364/ol.38.002800] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Photoacoustic tomography (PAT) is a hybrid imaging technique that has broad preclinical and clinical applications. Based on the photoacoustic effect, PAT directly measures specific optical absorption, which is the product of the tissue-intrinsic optical absorption coefficient and the local optical fluence. Therefore, quantitative PAT, such as absolute oxygen saturation (sO₂) quantification, requires knowledge of the local optical fluence, which can only be estimated through invasive measurements or sophisticated modeling of light transportation. In this Letter, we circumvent this requirement by taking advantage of the dynamics in sO₂. The new method works when the sO₂ transition can be simultaneously monitored with multiple wavelengths. For each wavelength, the ratio of photoacoustic amplitudes measured at different sO₂ states is utilized. Using the ratio cancels the contribution from optical fluence and allows calibration-free quantification of absolute sO₂. The new method was validated through both phantom and in vivo experiments.
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Affiliation(s)
| | | | | | | | | | - Lihong V. Wang
- Corresponding author: . Received Month X, XXXX; revised Month X, XXXX; accepted Month X, XXXX; posted Month X, XXXX (Doc. ID XXXXX); published Month X, XXXX
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87
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Wu D, Tao C, Liu X. Photoacoustic tomography extracted from speckle noise in acoustically inhomogeneous tissue. OPTICS EXPRESS 2013; 21:18061-7. [PMID: 23938677 DOI: 10.1364/oe.21.018061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Photoacoustic tomography is usually limited to acoustically homogeneous tissue. A hybrid scheme is developed to break this limitation by utilizing ultrasound to determine the unknown Green's function of inhomogeneous tissue. The method can effectively decrease the distortion and false contrast in images by extracting information from speckle noise. The method does not depend on the prior knowledge of tissue and the medium complexity. Moreover, the estimation of Green's function and the photoacoustic detection are performed by the same transducer. Therefore, the scheme could be easily integrated into a classical photoacoustic tomography system and extend its application in speckle environment.
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Affiliation(s)
- Dan Wu
- MOE Key Laboratory of Modern Acoustics, Nanjing University, Nanjing 210093, China
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88
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Wang P, Rajian JR, Cheng JX. Spectroscopic Imaging of Deep Tissue through Photoacoustic Detection of Molecular Vibration. J Phys Chem Lett 2013; 4:2177-2185. [PMID: 24073304 PMCID: PMC3780401 DOI: 10.1021/jz400559a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The quantized vibration of chemical bonds provides a way of imaging target molecules in a complex tissue environment. Photoacoustic detection of harmonic vibrational transitions provides an approach to visualize tissue content beyond the ballistic photon regime. This method involves pulsed laser excitation of overtone transitions in target molecules inside a tissue. Fast relaxation of the vibrational energy into heat results in a local temperature rise on the order of mK and a subsequent generation of acoustic waves detectable with an ultrasonic transducer. In this perspective, we review recent advances that demonstrate the advantages of vibration-based photoacoustic imaging and illustrate its potential in diagnosing cardiovascular plaques. An outlook into future development of vibrational photoacoustic endoscopy and tomography is provided.
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Affiliation(s)
- Pu Wang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907 USA
| | - Justin R. Rajian
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907 USA
| | - Ji-Xin Cheng
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907 USA
- Department of Chemistry, Purdue University, West Lafayette, IN 47907 USA
- Corresponding Author:
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89
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Lutzweiler C, Razansky D. Optoacoustic imaging and tomography: reconstruction approaches and outstanding challenges in image performance and quantification. SENSORS (BASEL, SWITZERLAND) 2013; 13:7345-84. [PMID: 23736854 PMCID: PMC3715274 DOI: 10.3390/s130607345] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/29/2013] [Accepted: 05/31/2013] [Indexed: 12/24/2022]
Abstract
This paper comprehensively reviews the emerging topic of optoacoustic imaging from the image reconstruction and quantification perspective. Optoacoustic imaging combines highly attractive features, including rich contrast and high versatility in sensing diverse biological targets, excellent spatial resolution not compromised by light scattering, and relatively low cost of implementation. Yet, living objects present a complex target for optoacoustic imaging due to the presence of a highly heterogeneous tissue background in the form of strong spatial variations of scattering and absorption. Extracting quantified information on the actual distribution of tissue chromophores and other biomarkers constitutes therefore a challenging problem. Image quantification is further compromised by some frequently-used approximated inversion formulae. In this review, the currently available optoacoustic image reconstruction and quantification approaches are assessed, including back-projection and model-based inversion algorithms, sparse signal representation, wavelet-based approaches, methods for reduction of acoustic artifacts as well as multi-spectral methods for visualization of tissue bio-markers. Applicability of the different methodologies is further analyzed in the context of real-life performance in small animal and clinical in-vivo imaging scenarios.
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Affiliation(s)
- Christian Lutzweiler
- Institute for Biological and Medical Imaging, Technical University of Munich and Helmholtz Center Munich, Ingolstadter Landstraße 1, Neuherberg 85764, Germany; E-Mail:
| | - Daniel Razansky
- Institute for Biological and Medical Imaging, Technical University of Munich and Helmholtz Center Munich, Ingolstadter Landstraße 1, Neuherberg 85764, Germany; E-Mail:
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90
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Nuster R, Schmitner N, Wurzinger G, Gratt S, Salvenmoser W, Meyer D, Paltauf G. Hybrid photoacoustic and ultrasound section imaging with optical ultrasound detection. JOURNAL OF BIOPHOTONICS 2013; 6:549-559. [PMID: 23650129 DOI: 10.1002/jbio.201200223] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 03/27/2013] [Accepted: 04/11/2013] [Indexed: 06/02/2023]
Abstract
A setup is proposed that provides perfectly co-registered photoacoustic (PA) and ultrasound (US) section images. Photoacoustic and ultrasound backscatter signals are generated by laser pulses coming from the same laser system, the latter by absorption of some of the laser energy on an optically absorbing target near the imaged object. By measuring both signals with the same optical detector, which is focused into the selected section by use of a cylindrical acoustic mirror, the information for both images is acquired simultaneously. Co-registered PA and US images are obtained after applying the inverse Radon transform to the data, which are gathered while rotating the object relative to the detector. Phantom experiments demonstrate a resolution of 1.1 mm between the sections of both imaging modalities and a in-plane resolution of about 60 µm and 120 µm for the US and PA modes, respectively. The complementary contrast mechanisms of the two modalities are shown by images of a zebrafish.
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Affiliation(s)
- Robert Nuster
- Department of Physics, Karl-Franzens University Graz, 8010 Graz, Austria.
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91
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Dima A, Gateau J, Claussen J, Wilhelm D, Ntziachristos V. Optoacoustic imaging of blood perfusion: techniques for intraoperative tissue viability assessment. JOURNAL OF BIOPHOTONICS 2013; 6:485-492. [PMID: 23494993 DOI: 10.1002/jbio.201200201] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 01/29/2013] [Accepted: 03/04/2013] [Indexed: 06/01/2023]
Abstract
Reliably assessing tissue viability during surgery is of major importance in surgical procedures. The most basic requirement for viability is sufficient oxygen supply to the tissue. Therefore it is highly desirable to visualize in real-time the dynamic process of blood perfusion up to and within the microvasculature. A modality sensitive to structures in the range of few hundred micrometers and offering high contrast to the embedding tissue is then needed. To this end, a number of methods have been developed, but have had no significant impact on the clinical routine due to various deficiencies. In this paper we demonstrate the applicability of optoacoustic imaging, which combines ultrasonic resolution with strong optical contrast. A method for optoacoustic perfusion assessment, based on a local and repeatable injection of saline, was proposed and assessed ex-vivo on large pig bowels and in-vivo in mouse tails. The obtained dynamic perfusion images highlight the method's potential to enable immediate and quantitative assessment of tissue viability during surgery.
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Affiliation(s)
- Alexander Dima
- Institute for Biological and Medical Imaging IBMI, Helmholtz Zentrum München, Germany
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92
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Buehler A, Kacprowicz M, Taruttis A, Ntziachristos V. Real-time handheld multispectral optoacoustic imaging. OPTICS LETTERS 2013; 38:1404-6. [PMID: 23632499 DOI: 10.1364/ol.38.001404] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Multispectral optoacoustic tomography (MSOT) of functional and molecular contrast has the potential to find broad deployment in clinical practice. We have developed the first handheld MSOT imaging device with fast wavelength tuning achieving a frame rate of 50 Hz. In this Letter, we demonstrate its clinical potential by dynamically resolving multiple disease-relevant tissue chromophores, including oxy-/deoxyhemoglobin, and melanin, in human volunteers.
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Affiliation(s)
- Andreas Buehler
- Institute for Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg 85764, Germany. andreas.buehler@helmholtz‑muenchen.de
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93
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Xia W, Piras D, van Hespen JC, Steenbergen W, Manohar S. A new acoustic lens material for large area detectors in photoacoustic breast tomography. PHOTOACOUSTICS 2013; 1:9-18. [PMID: 25302146 PMCID: PMC4134907 DOI: 10.1016/j.pacs.2013.05.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/13/2013] [Accepted: 05/16/2013] [Indexed: 05/07/2023]
Abstract
OBJECTIVES We introduce a new acoustic lens material for photoacoustic tomography (PAT) to improve lateral resolution while possessing excellent acoustic acoustic impedance matching with tissue to minimize lens induced image artifacts. BACKGROUND A large surface area detector due to its high sensitivity is preferable to detect weak signals in photoacoustic mammography. The lateral resolution is then limited by the narrow acceptance angle of such detectors. Acoustic lenses made of acrylic plastic (PMMA) have been used to enlarge the acceptance angle of such detectors and improve lateral resolution. However, such PMMA lenses introduce image artifacts due to internal reflections of ultrasound within the lenses, the result of acoustic impedance mismatch with the coupling medium or tissue. METHODS A new lens is proposed based on the 2-component resin Stycast 1090SI. We characterized the acoustic properties of the proposed lens material in comparison with commonly used PMMA, inspecting the speed of sound, acoustic attenuation and density. We fabricated acoustic lenses based on the new material and PMMA, and studied the effect of the acoustic lenses on detector performance comparing finite element (FEM) simulations and measurements of directional sensitivity, pulse-echo response and frequency response. We further investigated the effect of using the acoustic lenses on the image quality of a photoacoustic breast tomography system using k-Wave simulations and experiments. RESULTS Our acoustic characterization shows that Stycast 1090SI has tissue-like acoustic impedance, high speed of sound and low acoustic attenuation. These acoustic properties ensure an excellent acoustic lens material to minimize the acoustic insertion loss. Both acoustic lenses show significant enlargement of detector acceptance angle and lateral resolution improvement from modeling and experiments. However, the image artifacts induced by the presence of an acoustic lens are reduced using the proposed lens compared to PMMA lens, due to the minimization of internal reflections. CONCLUSIONS The proposed Stycast 1090SI acoustic lens improves the lateral resolution of photoacoustic tomography systems while not suffering from internal reflection-induced image artifacts compared a lens made of PMMA.
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Affiliation(s)
- Wenfeng Xia
- Biomedical Photonic Imaging group, Mira Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
| | - Daniele Piras
- Biomedical Photonic Imaging group, Mira Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
| | - Johan C.G. van Hespen
- Biomedical Photonic Imaging group, Mira Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
| | - Wiendelt Steenbergen
- Biomedical Photonic Imaging group, Mira Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
| | - Srirang Manohar
- Biomedical Photonic Imaging group, Mira Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
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94
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Jose J, Willemink RGH, Steenbergen W, Slump CH, van Leeuwen TG, Manohar S. Speed-of-sound compensated photoacoustic tomography for accurate imaging. Med Phys 2013; 39:7262-71. [PMID: 23231277 DOI: 10.1118/1.4764911] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
PURPOSE In most photoacoustic (PA) tomographic reconstructions, variations in speed-of-sound (SOS) of the subject are neglected under the assumption of acoustic homogeneity. Biological tissue with spatially heterogeneous SOS cannot be accurately reconstructed under this assumption. The authors present experimental and image reconstruction methods with which 2D SOS distributions can be accurately acquired and reconstructed, and with which the SOS map can be used subsequently to reconstruct highly accurate PA tomograms. METHODS The authors begin with a 2D iterative reconstruction approach in an ultrasound transmission tomography setting, which uses ray refracted paths instead of straight ray paths to recover accurate SOS images of the subject. Subsequently, they use the SOS distribution in a new 2D iterative PA reconstruction approach, where refraction of rays originating from PA sources is accounted for in accurately retrieving the distribution of these sources. Both the SOS reconstruction and SOS-compensated PA reconstruction methods utilize the Eikonal equation to model acoustic wavefront propagation. The equation is solved using a high accuracy fast marching method. RESULTS The authors validated the new reconstruction algorithms using numerical phantoms. For experiments they utilized the recently introduced PER-PACT method which can be used to simultaneously acquire SOS and PA data from subjects. CONCLUSIONS It is first confirmed that it is important to take SOS inhomogeneities into account in high resolution PA tomography. The iterative reconstruction algorithms, that model acoustic refractive effects, in reconstructing SOS distributions, and subsequently using these distributions to correct PA tomograms, yield artifact-free highly accurate images. The approach of using the hybrid measurement method and the new reconstruction algorithms is successful in substantially improving the quality of PA images with a minimization of blurring and artifacts.
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Affiliation(s)
- Jithin Jose
- University of Twente, AE Enschede, The Netherlands
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95
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Yang D, Zeng L, Pan C, Zhao X, Ji X. Noninvasive photoacoustic detecting intraocular foreign bodies with an annular transducer array. OPTICS EXPRESS 2013; 21:984-991. [PMID: 23388992 DOI: 10.1364/oe.21.000984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a fast photoacoustic imaging system based on an annular transducer array for detection of intraocular foreign bodies. An eight-channel data acquisition system is applied to capture the photoacoustic signals using multiplexing and the total time of data acquisition and transferring is within 3 s. A limited-view filtered back projection algorithm is used to reconstruct the photoacoustic images. Experimental models of intraocular metal and glass foreign bodies were constructed on ex vivo pig's eyes and clear photoacoustic images of intraocular foreign bodies were obtained. Experimental results demonstrate the photoacoustic imaging system holds the potential for in clinic detecting the intraocular foreign bodies.
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Affiliation(s)
- Diwu Yang
- Department of Physics and Engineering, Hunan University of Technology, Zhuzhou 412000, China.
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96
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Chang CC, Cho Y, Wang L, Zou J. Micromachined silicon acoustic delay lines for ultrasound applications. JOURNAL OF MICROMECHANICS AND MICROENGINEERING : STRUCTURES, DEVICES, AND SYSTEMS 2013; 23:025006. [PMID: 26523093 PMCID: PMC4627599 DOI: 10.1088/0960-1317/23/2/025006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this paper, we present the design, fabrication and testing of novel micromachined silicon-based acoustic delay lines. The acoustic properties of different silicon delay line structures have been characterized. Based on the experiment results, two different acoustic delay line systems (parallel and serial) have been successfully demonstrated to create controlled time delays in multiple channels of ultrasound signals. The time-delayed ultrasound signals are received with a single-element ultrasound transducer in a time-serial manner. This unique capability could be used to merge multiple signal channels, thereby enabling new ultrasound receiver designs with potentially less complexity and lower cost.
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Affiliation(s)
- Cheng-Chung Chang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Young Cho
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Lihong Wang
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Jun Zou
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
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97
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Yapici MK, Kim C, Chang CC, Jeon M, Guo Z, Cai X, Zou J, Wang LV. Parallel acoustic delay lines for photoacoustic tomography. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:116019. [PMID: 23139043 PMCID: PMC3491084 DOI: 10.1117/1.jbo.17.11.116019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Achieving real-time photoacoustic (PA) tomography typically requires multi-element ultrasound transducer arrays and their associated multiple data acquisition (DAQ) electronics to receive PA waves simultaneously. We report the first demonstration of a photoacoustic tomography (PAT) system using optical fiber-based parallel acoustic delay lines (PADLs). By employing PADLs to introduce specific time delays, the PA signals (on the order of a few micro seconds) can be forced to arrive at the ultrasonic transducers at different times. As a result, time-delayed PA signals in multiple channels can be ultimately received and processed in a serial manner with a single-element transducer, followed by single-channel DAQ electronics. Our results show that an optically absorbing target in an optically scattering medium can be photoacoustically imaged using the newly developed PADL-based PAT system. Potentially, this approach could be adopted to significantly reduce the complexity and cost of ultrasonic array receiver systems.
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Affiliation(s)
- Murat Kaya Yapici
- Khalifa University, Department of Electrical and Computer Engineering, Abu Dhabi, UAE
| | - Chulhong Kim
- The State University of New York, The University at Buffalo, Department of Biomedical Engineering, Buffalo, New York 14260
| | - Cheng-Chung Chang
- Texas A&M University, Department of Electrical and Computer Engineering, College Station, Texas 77843
| | - Mansik Jeon
- The State University of New York, The University at Buffalo, Department of Biomedical Engineering, Buffalo, New York 14260
| | - Zijian Guo
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130
| | - Xin Cai
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130
| | - Jun Zou
- Texas A&M University, Department of Electrical and Computer Engineering, College Station, Texas 77843
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130
- Address all correspondence to: Lihong V. Wang, Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130. Tel: 314-935-6152; Fax: 314-935-7448; E-mail:
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98
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Wang L, Maslov K, Xing W, Garcia-Uribe A, Wang LV. Video-rate functional photoacoustic microscopy at depths. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:106007. [PMID: 23224006 PMCID: PMC3461058 DOI: 10.1117/1.jbo.17.10.106007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 09/07/2012] [Accepted: 09/10/2012] [Indexed: 05/18/2023]
Abstract
We report the development of functional photoacoustic microscopy capable of video-rate high-resolution in vivo imaging in deep tissue. A lightweight photoacoustic probe is made of a single-element broadband ultrasound transducer, a compact photoacoustic beam combiner, and a bright-field light delivery system. Focused broadband ultrasound detection provides a 44-μm lateral resolution and a 28-μm axial resolution based on the envelope (a 15-μm axial resolution based on the raw RF signal). Due to the efficient bright-field light delivery, the system can image as deep as 4.8 mm in vivo using low excitation pulse energy (28 μJ per pulse, 0.35 mJ/cm² on the skin surface). The photoacoustic probe is mounted on a fast-scanning voice-coil scanner to acquire 40 two-dimensional (2-D) B-scan images per second over a 9-mm range. High-resolution anatomical imaging is demonstrated in the mouse ear and brain. Via fast dual-wavelength switching, oxygen dynamics of mouse cardio-vasculature is imaged in realtime as well.
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Affiliation(s)
- Lidai Wang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, Campus Box 1097, One Brookings Drive, St. Louis, Missouri 63130-4899
| | - Konstantin Maslov
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, Campus Box 1097, One Brookings Drive, St. Louis, Missouri 63130-4899
| | - Wenxin Xing
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, Campus Box 1097, One Brookings Drive, St. Louis, Missouri 63130-4899
| | - Alejandro Garcia-Uribe
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, Campus Box 1097, One Brookings Drive, St. Louis, Missouri 63130-4899
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, Campus Box 1097, One Brookings Drive, St. Louis, Missouri 63130-4899
- Address all correspondence to: Lihong V. Wang, Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, Campus Box 1097, One Brookings Drive, St. Louis, Missouri 63130-4899. Tel: (314) 935-6152; Fax: (314) 935-7448; E-mail:
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99
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Buehler A, Deán-Ben XL, Claussen J, Ntziachristos V, Razansky D. Three-dimensional optoacoustic tomography at video rate. OPTICS EXPRESS 2012; 20:22712-9. [PMID: 23037421 DOI: 10.1364/oe.20.022712] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Using optoacoustic excitation, a complete volumetric tomographic data sets from the imaged object can in principle be generated with a single interrogating laser pulse. Thus, optoacoustic imaging intrinsically has the potential for fast three-dimensional imaging. We have developed a system capable of acquiring volumetric optoacoustic data in real time and showcase in this work the undocumented capacity to generate high resolution three-dimensional optoacoustic images at a rate of 10 Hz, currently mainly limited by the pulse repetition rate of the excitation laser.
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Affiliation(s)
- A Buehler
- Institute for Biological and Medical Imaging, Technische Universität München and Helmholtz Zentrum München, Ingoldstädter Landstraße 1, D-85764 Neuherberg, Germany
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100
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Yao J, Xia J, Maslov KI, Nasiriavanaki M, Tsytsarev V, Demchenko AV, Wang LV. Noninvasive photoacoustic computed tomography of mouse brain metabolism in vivo. Neuroimage 2012; 64:257-66. [PMID: 22940116 DOI: 10.1016/j.neuroimage.2012.08.054] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 08/13/2012] [Accepted: 08/15/2012] [Indexed: 10/28/2022] Open
Abstract
We have demonstrated the feasibility of imaging mouse brain metabolism using photoacoustic computed tomography (PACT), a fast, noninvasive and functional imaging modality with optical contrast and acoustic resolution. Brain responses to forepaw stimulations were imaged transdermally and transcranially. 2-NBDG, which diffuses well across the blood-brain-barrier, provided exogenous contrast for photoacoustic imaging of glucose response. Concurrently, hemoglobin provided endogenous contrast for photoacoustic imaging of hemodynamic response. Glucose and hemodynamic responses were quantitatively decoupled by using two-wavelength measurements. We found that glucose uptake and blood perfusion around the somatosensory region of the contralateral hemisphere were both increased by stimulations, indicating elevated neuron activity. While the glucose response area was more homogenous and confined within the somatosensory region, the hemodynamic response area had a clear vascular pattern and spread wider than the somatosensory region. Our results demonstrate that 2-NBDG-enhanced PACT is a promising tool for noninvasive studies of brain metabolism.
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Affiliation(s)
- Junjie Yao
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
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