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Bureau F, Robin J, Le Ber A, Lambert W, Fink M, Aubry A. Three-dimensional ultrasound matrix imaging. Nat Commun 2023; 14:6793. [PMID: 37880210 PMCID: PMC10600255 DOI: 10.1038/s41467-023-42338-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 10/05/2023] [Indexed: 10/27/2023] Open
Abstract
Matrix imaging paves the way towards a next revolution in wave physics. Based on the response matrix recorded between a set of sensors, it enables an optimized compensation of aberration phenomena and multiple scattering events that usually drastically hinder the focusing process in heterogeneous media. Although it gave rise to spectacular results in optical microscopy or seismic imaging, the success of matrix imaging has been so far relatively limited with ultrasonic waves because wave control is generally only performed with a linear array of transducers. In this paper, we extend ultrasound matrix imaging to a 3D geometry. Switching from a 1D to a 2D probe enables a much sharper estimation of the transmission matrix that links each transducer and each medium voxel. Here, we first present an experimental proof of concept on a tissue-mimicking phantom through ex-vivo tissues and then, show the potential of 3D matrix imaging for transcranial applications.
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Affiliation(s)
- Flavien Bureau
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 75005, Paris, France
| | - Justine Robin
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 75005, Paris, France
- Physics for Medicine, ESPCI Paris, PSL University, INSERM, CNRS, Paris, France
| | - Arthur Le Ber
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 75005, Paris, France
| | - William Lambert
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 75005, Paris, France
- Hologic / SuperSonic Imagine, 135 Rue Emilien Gautier, 13290, Aix-en-Provence, France
| | - Mathias Fink
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 75005, Paris, France
| | - Alexandre Aubry
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 75005, Paris, France.
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2
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Koike T, Tomii N, Watanabe Y, Azuma T, Takagi S. Deep learning for hetero-homo conversion in channel-domain for phase aberration correction in ultrasound imaging. ULTRASONICS 2023; 129:106890. [PMID: 36462461 DOI: 10.1016/j.ultras.2022.106890] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 10/21/2022] [Accepted: 11/13/2022] [Indexed: 06/17/2023]
Abstract
Echo imaging in ultrasound computed tomography (USCT) using the synthetic aperture technique is performed with the assumption that the speed of sound is constant in the system. However, tissue heterogeneity causes a mismatch between the predicted arrival time and the actual arrival time of the echo signal, which will result in phase aberration, leading to the quality degradation of the reconstructed B-mode image. The conventional correction methods that use the correlation of each different channel require the presence of strong point scatterers and involve the problem of local solutions due to excessive correction. In this study, we propose a novel approach to correcting the signal distortion due to sound speed heterogeneity using a deep neural network (DNN). The DNN was trained to convert the distorted radio frequency (RF) inputs for the heterogeneous medium to the distortion-free RF outputs for the homogeneous medium. The network with U-net architecture using ResNet-34 as a backbone was trained using the hetero-homo corresponding channel-domain RF data generated via numerical simulations. The trained network performed phase aberration correction in the channel-domain RF, with the B-mode images reconstructed with the corrected RF demonstrating a higher contrast and an improved resolution compared with uncorrected cases. It was also demonstrated that the DNN model is robust to both varied reflection intensities and varied sound speed heterogeneities. The successful results demonstrated that the proposed DNN-based method is effective for phase aberration correction in US imaging.
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Affiliation(s)
- Tatsuki Koike
- Faculty of Engineering, The University of Tokyo, 7-3-1, Bunkyo-ku, 113-8656, Tokyo, Japan
| | - Naoki Tomii
- Faculty of Engineering, The University of Tokyo, 7-3-1, Bunkyo-ku, 113-8656, Tokyo, Japan.
| | - Yoshiki Watanabe
- Faculty of Engineering, The University of Tokyo, 7-3-1, Bunkyo-ku, 113-8656, Tokyo, Japan
| | - Takashi Azuma
- Faculty of Engineering, The University of Tokyo, 7-3-1, Bunkyo-ku, 113-8656, Tokyo, Japan
| | - Shu Takagi
- Faculty of Engineering, The University of Tokyo, 7-3-1, Bunkyo-ku, 113-8656, Tokyo, Japan
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3
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Lambert W, Cobus LA, Robin J, Fink M, Aubry A. Ultrasound Matrix Imaging-Part II: The Distortion Matrix for Aberration Correction Over Multiple Isoplanatic Patches. IEEE TRANSACTIONS ON MEDICAL IMAGING 2022; 41:3921-3938. [PMID: 35976837 DOI: 10.1109/tmi.2022.3199483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This is the second article in a series of two which report on a matrix approach for ultrasound imaging in heterogeneous media. This article describes the quantification and correction of aberration, i.e. the distortion of an image caused by spatial variations in the medium speed-of-sound. Adaptive focusing can compensate for aberration, but is only effective over a restricted area called the isoplanatic patch. Here, we use an experimentally-recorded matrix of reflected acoustic signals to synthesize a set of virtual transducers. We then examine wave propagation between these virtual transducers and an arbitrary correction plane. Such wave-fronts consist of two components: (i) An ideal geometric wave-front linked to diffraction and the input focusing point, and; (ii) Phase distortions induced by the speed-of-sound variations. These distortions are stored in a so-called distortion matrix, the singular value decomposition of which gives access to an optimized focusing law at any point. We show that, by decoupling the aberrations undergone by the outgoing and incoming waves and applying an iterative strategy, compensation for even high-order and spatially-distributed aberrations can be achieved. After a numerical validation of the process, ultrasound matrix imaging (UMI) is applied to the in-vivo imaging of a gallbladder. A map of isoplanatic modes is retrieved and is shown to be strongly correlated with the arrangement of tissues constituting the medium. The corresponding focusing laws yield an ultrasound image with drastically improved contrast and transverse resolution. UMI thus provides a flexible and powerful route towards computational ultrasound.
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Lambert W, Robin J, Cobus LA, Fink M, Aubry A. Ultrasound Matrix Imaging-Part I: The Focused Reflection Matrix, the F-Factor and the Role of Multiple Scattering. IEEE TRANSACTIONS ON MEDICAL IMAGING 2022; 41:3907-3920. [PMID: 35976836 DOI: 10.1109/tmi.2022.3199498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This is the first article in a series of two dealing with a matrix approach for aberration quantification and correction in ultrasound imaging. Advanced synthetic beamforming relies on a double focusing operation at transmission and reception on each point of the medium. Ultrasound matrix imaging (UMI) consists in decoupling the location of these transmitted and received focal spots. The response between those virtual transducers form the so-called focused reflection matrix that actually contains much more information than a confocal ultrasound image. In this paper, a time-frequency analysis of this matrix is performed, which highlights the single and multiple scattering contributions as well as the impact of aberrations in the monochromatic and broadband regimes. Interestingly, this analysis enables the measurement of the incoherent input-output point spread function at any pixel of this image. A fitting process enables the quantification of the single scattering, multiple scattering and noise components in the image. From the single scattering contribution, a focusing criterion is defined, and its evolution used to quantify the amount of aberration throughout the ultrasound image. In contrast to the state-of-the-art coherence factor, this new indicator is robust to multiple scattering and electronic noise, thereby providing a contrasted map of the focusing quality at a much better transverse resolution. After a validation of the proof-of-concept based on time-domain simulations, UMI is applied to the in-vivo study of a human calf. Beyond this specific example, UMI opens a new route for speed-of-sound and scattering quantification in ultrasound imaging.
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Jiang C, Li Y, Xu K, Ta D. Full-Matrix Phase Shift Migration Method for Transcranial Ultrasonic Imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:72-83. [PMID: 32795967 DOI: 10.1109/tuffc.2020.3016382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A spectrum-domain method, called full-matrix phase shift migration (FM-PSM), is presented for transcranial ultrasound phase correction and imaging with ideal synthetic aperture focusing technology. The simulated data obtained using the pseudospectral time-domain method are used to evaluate the feasibility of the method. The experimental data measured from a 3-D printed skull phantom are used to evaluate the algorithm performance in terms of resolution, contrast-to-noise ratio (CNR), and eccentricity comparing with the classical ray-tracing delay and sum (DAS) method. In wire imaging experiment, FM-PSM has a lateral resolution of 0.22 mm and ray-tracing DAS has a lateral resolution of 0.24 mm measured at -6-dB drop using a transducer with a center frequency of 6.25 MHz. In cylinder imaging experiment, FM-PSM has a CNR of 2.14 and ray-tracing DAS has a CNR of 1.82, which illustrates about 17% improvement. For a J -element array and an output image with pixels M ×N (lateral × axial), the computational cost of the DAS is of O(J ×M2×N2) ; on the contrary, it reduces to O(J ×M ×N2) with the proposed FM-PSM. The results suggest that FM-PSM is an efficiency method for transcranial ultrasonic imaging.
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Bendjador H, Deffieux T, Tanter M. The SVD Beamformer: Physical Principles and Application to Ultrafast Adaptive Ultrasound. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:3100-3112. [PMID: 32286965 DOI: 10.1109/tmi.2020.2986830] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A shift of paradigm is currently underway in biomedical ultrasound thanks to plane or diverging waves coherent compounding for faster imaging. One remaining challenge consists in handling phase and amplitude aberrations induced during the ultrasonic propagation through complex layers. Unlike conventional line-per-line imaging, ultrafast ultrasound provides backscattering information from the whole imaged area for each transmission. Here, we take benefit from this feature and propose an efficient approach to perform fast aberration correction. Our method is based on the Singular Value Decomposition (SVD) of an ultrafast compound matrix containing backscattered data for several plane wave transmissions. First, we explain the physical signification of SVD and associated singular vectors within the ultrafast matrix formalism. We theoretically demonstrate that the separation of spatial and angular variables, rendered by SVD on ultrafast data, provides an elegant and straightforward way to optimize the angular coherence of backscattered data. In heterogeneous media, we demonstrate that the first spatial and angular singular vectors retrieve respectively the non-aberrated image of a region of interest, and the phase and amplitude of its aberration law. Numerical, in vitro and in vivo results prove the efficiency of the image correction, but also the accuracy of the aberrator determination. Based on spatial and angular coherence, we introduce a complete methodology for adaptive beamforming of ultrafast data, performed on successive isoplanatism patches undergoing SVD beamforming. The simplicity of this method paves the way to real-time adaptive ultrafast ultrasound imaging and provides a theoretical framework for future quantitative ultrasound applications.
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Badon A, Barolle V, Irsch K, Boccara AC, Fink M, Aubry A. Distortion matrix concept for deep optical imaging in scattering media. SCIENCE ADVANCES 2020; 6:eaay7170. [PMID: 32923603 PMCID: PMC7455485 DOI: 10.1126/sciadv.aay7170] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 06/05/2020] [Indexed: 05/03/2023]
Abstract
In optical imaging, light propagation is affected by the inhomogeneities of the medium. Sample-induced aberrations and multiple scattering can strongly degrade the image resolution and contrast. On the basis of a dynamic correction of the incident and/or reflected wavefronts, adaptive optics has been used to compensate for those aberrations. However, it only applies to spatially invariant aberrations or to thin aberrating layers. Here, we propose a global and noninvasive approach based on the distortion matrix concept. This matrix basically connects any focusing point of the image with the distorted part of its wavefront in reflection. A singular value decomposition of the distortion matrix allows to correct for high-order aberrations and forward multiple scattering over multiple isoplanatic modes. Proof-of-concept experiments are performed through biological tissues including a turbid cornea. We demonstrate a Strehl ratio enhancement up to 2500 and recover a diffraction-limited resolution until a depth of 10 scattering mean free paths.
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Affiliation(s)
- Amaury Badon
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 1 rue Jussieu, 75005 Paris, France
| | - Victor Barolle
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 1 rue Jussieu, 75005 Paris, France
| | - Kristina Irsch
- Vision Institute/Quinze-Vingts National Eye Hospital, Sorbonne University, CNRS UMR 7210, INSERM U 068, 17 rue Moreau, 75012 Paris, France
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - A. Claude Boccara
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 1 rue Jussieu, 75005 Paris, France
| | - Mathias Fink
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 1 rue Jussieu, 75005 Paris, France
| | - Alexandre Aubry
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 1 rue Jussieu, 75005 Paris, France
- Corresponding author.
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8
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Lambert W, Cobus LA, Frappart T, Fink M, Aubry A. Distortion matrix approach for ultrasound imaging of random scattering media. Proc Natl Acad Sci U S A 2020; 117:14645-14656. [PMID: 32522873 PMCID: PMC7334504 DOI: 10.1073/pnas.1921533117] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Focusing waves inside inhomogeneous media is a fundamental problem for imaging. Spatial variations of wave velocity can strongly distort propagating wave fronts and degrade image quality. Adaptive focusing can compensate for such aberration but is only effective over a restricted field of view. Here, we introduce a full-field approach to wave imaging based on the concept of the distortion matrix. This operator essentially connects any focal point inside the medium with the distortion that a wave front, emitted from that point, experiences due to heterogeneities. A time-reversal analysis of the distortion matrix enables the estimation of the transmission matrix that links each sensor and image voxel. Phase aberrations can then be unscrambled for any point, providing a full-field image of the medium with diffraction-limited resolution. Importantly, this process is particularly efficient in random scattering media, where traditional approaches such as adaptive focusing fail. Here, we first present an experimental proof of concept on a tissue-mimicking phantom and then, apply the method to in vivo imaging of human soft tissues. While introduced here in the context of acoustics, this approach can also be extended to optical microscopy, radar, or seismic imaging.
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Affiliation(s)
- William Lambert
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 75005 Paris, France
- SuperSonic Imagine, 13857 Aix-en-Provence, France
| | - Laura A Cobus
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 75005 Paris, France
| | | | - Mathias Fink
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 75005 Paris, France
| | - Alexandre Aubry
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 75005 Paris, France;
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9
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Reconstruction of Photoacoustic Tomography Inside a Scattering Layer Using a Matrix Filtering Method. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9102071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Photoacoustic (PA) tomography (PAT) has potential for use in brain imaging due to its rich optical contrast, high acoustic resolution in deep tissue, and good biosafety. However, the skull often poses challenges for transcranial brain imaging. The skull can cause severe distortion and attenuation of the phase and amplitude of PA waves, which leads to poor resolution, low contrast, and strong noise in the images. In this study, we propose an image reconstruction method to recover the PA image insider a skull-like scattering layer. This method reduces the scattering artifacts by combining a correlation matrix filter and a time reversal operator. Both numerical simulations and PA imaging experiments demonstrate that the proposed approach effectively improves the image quality with less speckle noise and better signal-to-noise ratio. The proposed method may improve the quality of PAT in a complex acoustic scattering environment, such as transcranial brain imaging.
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Rui W, Tao C, Liu X. Imaging acoustic sources through scattering media by using a correlation full-matrix filter. Sci Rep 2018; 8:15611. [PMID: 30353141 PMCID: PMC6199323 DOI: 10.1038/s41598-018-34039-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 10/10/2018] [Indexed: 12/25/2022] Open
Abstract
In the inhomogeneous medium, acoustic scattering is always a fundamental challenge for photoacoustic imaging. We implement a correlation full-matrix filter (CFMF) combing with a time reversal operator to improve the imaging quality of acoustic sources in complex media. The correlation full-matrix filtering process extracts the direct wave component from the detected signal and preserve all the useful information at the same time. A location factor is considered in the time reversal operator to compensate for the image distortion and false contrast caused by the limited-view detection. The numerical simulations demonstrate that the proposed approach can perform good imaging quality with the higher image signal-noise ratio and better resolution in an acoustic scattering environment. This scheme might be applied to improve the photoacoustic imaging for inhomogeneous biological tissues.
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Affiliation(s)
- Wei Rui
- Laboratory of Modern Acoustics, Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Chao Tao
- Laboratory of Modern Acoustics, Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China. .,Shenzhen Research Institute of Nanjing University, Shenzhen, 51800, China.
| | - Xiaojun Liu
- Laboratory of Modern Acoustics, Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
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Rui W, Tao C, Liu X. Photoacoustic imaging in scattering media by combining a correlation matrix filter with a time reversal operator. OPTICS EXPRESS 2017; 25:22840-22850. [PMID: 29041590 DOI: 10.1364/oe.25.022840] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 09/06/2017] [Indexed: 06/07/2023]
Abstract
Acoustic scattering medium is a fundamental challenge for photoacoustic imaging. In this study, we reveal the different coherent properties of the scattering photoacoustic waves and the direct photoacoustic waves in a matrix form. Direct waves show a particular coherence on the antidiagonals of the matrix, whereas scattering waves do not. Based on this property, a correlation matrix filter combining with a time reversal operator is proposed to preserve the direct waves and recover the image behind a scattering layer. Both numerical simulations and photoacoustic imaging experiments demonstrate that the proposed approach effectively increases the image contrast and decreases the background speckles in a scattering medium. This study might improve the quality of photoacoustic imaging in an acoustic scattering environment and extend its applications.
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12
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Thouvenin O, Grieve K, Xiao P, Apelian C, Boccara AC. En face coherence microscopy [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:622-639. [PMID: 28270972 PMCID: PMC5330590 DOI: 10.1364/boe.8.000622] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/29/2016] [Accepted: 12/31/2016] [Indexed: 05/13/2023]
Abstract
En face coherence microscopy or flying spot or full field optical coherence tomography or microscopy (FF-OCT/FF-OCM) belongs to the OCT family because the sectioning ability is mostly linked to the source coherence length. In this article we will focus our attention on the advantages and the drawbacks of the following approaches: en face versus B scan tomography in terms of resolution, coherent versus incoherent illumination and influence of aberrations, and scanning versus full field imaging. We then show some examples to illustrate the diverse applications of en face coherent microscopy and show that endogenous or exogenous contrasts can add valuable information to the standard morphological image. To conclude we discuss a few domains that appear promising for future development of en face coherence microscopy.
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Affiliation(s)
- Olivier Thouvenin
- Institut Langevin ESPCI, PSL Research University, CNRS UMR7587 1rue Jussieu, Paris F75005, France
| | - Kate Grieve
- CHNO des Quinze Vingts/Institut de la Vision, 28 rue de Charenton, Paris F75012, France
| | - Peng Xiao
- Institut Langevin ESPCI, PSL Research University, CNRS UMR7587 1rue Jussieu, Paris F75005, France
| | - Clement Apelian
- Institut Langevin ESPCI, PSL Research University, CNRS UMR7587 1rue Jussieu, Paris F75005, France; LLTech Pépinière Paris Santé Cochin 29 rue du Faubourg Saint Jacques Paris F75014, France
| | - A Claude Boccara
- Institut Langevin ESPCI, PSL Research University, CNRS UMR7587 1rue Jussieu, Paris F75005, France
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Badon A, Li D, Lerosey G, Boccara AC, Fink M, Aubry A. Smart optical coherence tomography for ultra-deep imaging through highly scattering media. SCIENCE ADVANCES 2016; 2:e1600370. [PMID: 27847864 PMCID: PMC5099988 DOI: 10.1126/sciadv.1600370] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 09/27/2016] [Indexed: 05/18/2023]
Abstract
Multiple scattering of waves in disordered media is a nightmare whether it is for detection or imaging purposes. So far, the best approach to get rid of multiple scattering is optical coherence tomography. This basically combines confocal microscopy and coherence time gating to discriminate ballistic photons from a predominant multiple scattering background. Nevertheless, the imaging-depth range remains limited to 1 mm at best in human soft tissues because of aberrations and multiple scattering. We propose a matrix approach of optical imaging to push back this fundamental limit. By combining a matrix discrimination of ballistic waves and iterative time reversal, we show, both theoretically and experimentally, an extension of the imaging-depth limit by at least a factor of 2 compared to optical coherence tomography. In particular, the reported experiment demonstrates imaging through a strongly scattering layer from which only 1 reflected photon out of 1000 billion is ballistic. This approach opens a new route toward ultra-deep tissue imaging.
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Kober J, Dvorakova Z, Prevorovsky Z, Krofta J. Time reversal transfer: Exploring the robustness of time reversed acoustics in media with geometry perturbations. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2015; 138:EL49-EL53. [PMID: 26233060 DOI: 10.1121/1.4922623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this letter, fundamentals of transferring a time reversal experiment between similar objects are discussed. The time reversal experiment consists of two steps: forward propagation, when a source excites the medium and a complex wave field is created, and back propagation, resulting in time reversal focusing. Here the procedure of performing the first step on one specimen and the second step on another is investigated. The theory of time reversal transfer is explained on an example of object shape variations. However, conclusions of the theoretical analysis are applicable universally. The feasibility of the proposed procedure is validated in experiments modeling conditions in practice.
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Affiliation(s)
- Jan Kober
- Institute of Thermomechanics, Academy of Sciences of the Czech Republic, Dolejskova 5, 18200 Prague 8, Czech Republic , , ,
| | - Zuzana Dvorakova
- Institute of Thermomechanics, Academy of Sciences of the Czech Republic, Dolejskova 5, 18200 Prague 8, Czech Republic , , ,
| | - Zdenek Prevorovsky
- Institute of Thermomechanics, Academy of Sciences of the Czech Republic, Dolejskova 5, 18200 Prague 8, Czech Republic , , ,
| | - Josef Krofta
- Institute of Thermomechanics, Academy of Sciences of the Czech Republic, Dolejskova 5, 18200 Prague 8, Czech Republic , , ,
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15
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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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16
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Li Y, Robinson B. Timing-error-difference calibration of a two-dimensional array imaging system using the overlapping-subaperture algorithm. ULTRASONICS 2012; 52:1005-1009. [PMID: 22947242 DOI: 10.1016/j.ultras.2012.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 07/13/2012] [Accepted: 08/02/2012] [Indexed: 06/01/2023]
Abstract
Timing errors in the transmitting and receiving electronic channels of an imaging system can generate different transmission and reception phase-aberration profiles. To decide if these two profiles need to be measured separately, an overlapping-subaperture algorithm has been proposed in a previous paper to measure the difference between timing errors in transmitting and receiving channels connected to each element in a two-dimensional array. This algorithm has been used to calibrate a custom built imaging system with a curved linear two-dimensional array, and the results are presented in this paper. The experimental results have demonstrated that the overlapping-subaperture algorithm is capable of calibrating the timing-error-difference profile of this imaging system with a standard deviation of only a few nanoseconds. Experimental results have also shown that the time-error-difference profile of this imaging system is smaller than one tenth of a wavelength and there is no need to measure the transmission and reception phase-aberration profiles separately. The derived average phase-aberration profile using the near-field signal-redundancy algorithm can be used to correct phase aberrations for both transmission and reception.
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Affiliation(s)
- Yue Li
- Information and Communication Technologies Center, Commonwealth Scientific and Industrial Research Organisation, Marsfield, NSW 2122, Australia.
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17
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Li Y, Robinson B. Correction of tissue-motion effects on common-midpoint signals using reciprocal signals. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2012; 132:872-882. [PMID: 22894210 DOI: 10.1121/1.4730913] [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
The near field signal redundancy algorithm for phase-aberration correction is sensitive to tissue motion because several separated transmissions are usually needed to acquire a set of common-midpoint signals. If tissues are moving significantly due to, for example, heart beats, the effects of tissue motion on common-midpoint signals need to be corrected before the phase-aberration profile can be successfully measured. Theoretical analyses in this paper show that the arrival-time difference between a pair of common-midpoint signals due to tissue motion is usually very similar to that between the pair of reciprocal signals acquired using the same two transmissions. Based on this conclusion, an algorithm for correcting tissue-motion effects on the peak position of cross-correlation functions between common-midpoint signals is proposed and initial experimental results are also presented.
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Affiliation(s)
- Yue Li
- Information and Communication Technologies Centre, Commonwealth Scientific and Industrial Research Organisation, Marsfield, New South Wales 2122, Australia.
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Osmanski BF, Montaldo G, Tanter M, Fink M. Aberration correction by time reversal of moving speckle noise. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2012; 59:1575-1583. [PMID: 22828852 DOI: 10.1109/tuffc.2012.2357] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Focusing a wave through heterogeneous media is an important problem in medical ultrasound imaging. In such aberrating media, in the presence of a small number of point reflectors, iterative time reversal is a well-known method able to focus on the strongest reflector. However, in presence of speckle noise generated by many non-resolved scatterers, iterative time reversal alone does not work. In this paper, we propose the use of the echoes coming from moving particles in a flow, such as red blood cells, to generate a virtual point reflector by iterative time reversal. The construction of the virtual point reflector is performed by a coherent addition of independent realizations of speckle coming from moving particles. After focusing on a virtual point reflector, ultrasound images can be locally corrected inside an isoplanatic patch. An application for the correction of power Doppler images is presented. A theoretical analysis shows that this iterative method allows focusing on the point of maximal insonification of the uncorrected beam.
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Affiliation(s)
- Bruno-Felix Osmanski
- Institut Langevin, Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris-ESPCI, ParisTech, Inserm U979, CNRS UMR7587, Universite Denis Diderot, France.
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19
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Montaldo G, Tanter M, Fink M. Time reversal of speckle noise. PHYSICAL REVIEW LETTERS 2011; 106:054301. [PMID: 21405400 DOI: 10.1103/physrevlett.106.054301] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 12/27/2010] [Indexed: 05/30/2023]
Abstract
Focusing a wave in an unknown inhomogeneous medium is an open problem in wave physics. This work presents an iterative method able to focus in pulse-echo mode in an inhomogeneous medium containing a random distribution of scatterers. By performing a coherent summation of the random echoes backscattered from a set of points surrounding the desired focus, a virtual bright pointlike reflector is generated. A time-reversal method enables an iterative convergence towards the optimal wave field focusing at the location of this virtual scatterer. Thanks to this iterative time-reversal process, it is possible to focus at any arbitrary point in the heterogeneous medium even in the absence of pointlike source. An experimental demonstration is given for the correction of strongly distorted images in the field of medical ultrasound imaging. This concept enables envisioning many other applications in wave physics.
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Affiliation(s)
- Gabriel Montaldo
- Institut Langevin, ESPCI ParisTech, CNRS, INSERM, Université Paris VII, 10 rue Vauquelin, 75005, Paris, France
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Guo G, Yang Y, Sun C. Reverberation nulling and echo enhancement at low frequency using waveguide invariance. CHINESE SCIENCE BULLETIN-CHINESE 2011. [DOI: 10.1007/s11434-010-4207-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Dianis SW, von Ramm OT. Harmonic source wavefront aberration correction for ultrasound imaging. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2011; 129:507-17. [PMID: 21303031 PMCID: PMC3055292 DOI: 10.1121/1.3518771] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 10/28/2010] [Accepted: 10/29/2010] [Indexed: 05/24/2023]
Abstract
A method is proposed which uses a lower-frequency transmit to create a known harmonic acoustical source in tissue suitable for wavefront correction without a priori assumptions of the target or requiring a transponder. The measurement and imaging steps of this method were implemented on the Duke phased array system with a two-dimensional (2-D) array. The method was tested with multiple electronic aberrators [0.39π to 1.16π radians root-mean-square (rms) at 4.17 MHz] and with a physical aberrator 0.17π radians rms at 4.17 MHz) in a variety of imaging situations. Corrections were quantified in terms of peak beam amplitude compared to the unaberrated case, with restoration between 0.6 and 36.6 dB of peak amplitude with a single correction. Standard phantom images before and after correction were obtained and showed both visible improvement and 14 dB contrast improvement after correction. This method, when combined with previous phase correction methods, may be an important step that leads to improved clinical images.
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Affiliation(s)
- Scott W Dianis
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708-0281, USA
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Robert JL, Fink M. Spatio-temporal invariants of the time reversal operator. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2010; 127:2904-2912. [PMID: 21117741 DOI: 10.1121/1.3372642] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The decomposition of the time reversal operator, known by the French acronym DORT, is a technique to extract point scatterers' monochromatic Green's functions from a medium. It is used to detect, locate, and focus on scatterers in various domains such as underwater acoustics, medical ultrasound, and nondestructive evaluation. A limitation of the method arises from its single-frequency nature, when the signals used in acoustics are often broadband. Reconstruction of the broadband Green's functions from the single-frequency Green's functions can be very difficult when numerous scatterers are present in the medium. Moreover, the method does not take advantage of the axial resolution associated with broadband signals. Time domain methods are investigated here as an answer to these problems. It is shown that the time reversal operator in the time domain takes the form of a tensor. The properties of the invariants are discussed. It is shown they do not have all the expected properties. Another method is proposed that requires a priori information on the medium.
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Affiliation(s)
- Jean-Luc Robert
- Philips Research North America, 345 Scarborough Road, Briarcliff Manor, New York 10510, USA
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Walker SC, Roux P, Kuperman WA. Synchronized time-reversal focusing with application to remote imaging from a distant virtual source array. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2009; 125:3828-34. [PMID: 19507965 DOI: 10.1121/1.3117374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Time-reversing the transfer function between a time-reversal mirror (TRM) and a distant probe source location generates an acoustic spatio-temporal focus at the location. It is shown that a TR focus behaves as a "virtual" source (in the far-field limit) in the outbound direction with respect to the TRM. By extension, a collection of TRM-to-probe source transfer functions constitutes a virtual source array (VSA) that can serve as a remote platform for active imaging methods such as beam-steering and other coherent wavefront techniques. As a demonstration, a set of a-priori sampled TRM-to-VSA transfer functions are steered to coherently focus at a selected location beyond the VSA for which the transfer function is not known a-priori. In this case the VSA acts as a lens that refocuses the TRM field to the target location. Under proper conditions, the resolution is comparable to that of standard TR. While the specific application of active focusing is presented as a validation of the concept, the relationship between coherent focusing and the transfer function implies that the virtual array concept may find use in a range of imaging methods, both active and passive. Possible applications are discussed, and simulation and experimental results are presented.
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Affiliation(s)
- S C Walker
- Marine Physical Laboratory of the Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093-0238, USA.
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Robert JL, Fink M. The prolate spheroidal wave functions as invariants of the time reversal operator for an extended scatterer in the Fraunhofer approximation. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2009; 125:218-226. [PMID: 19173409 DOI: 10.1121/1.3023060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The decomposition of the time reversal operator, known by the French acronym DORT, is widely used to detect, locate, and focus on scatterers in various domains such as underwater acoustics, medical ultrasound, and nondestructive evaluation. In the case of point-scatterers, the theory is well understood: The number of nonzero eigenvalues is equal to the number of scatterers, and the eigenvectors correspond to the scatterers Green's function. In the case of extended objects, however, the formalism is not as simple. It is shown here that, in the Fraunhofer approximation, analytical solutions can be found and that the solutions are functions called prolate spheroidal wave-functions. These functions have been studied in information theory as a basis of band-limited and time-limited signals. They also arise in optics. The theoretical solutions are compared to simulation results. Most importantly, the intuition that for an extended objects, the number of nonzero eigenvalues is proportional to the number of resolution cell in the object is justified. The case of three-dimensional objects imaged by a two-dimensional array is also dealt with. Comparison with previous solutions is made, and an application to super-resolution of scatterers is presented.
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Affiliation(s)
- Jean-Luc Robert
- Philips Research North America, Briarcliff Manor, New York 10510, USA
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Robert JL, Fink M. The time-reversal operator with virtual transducers: application to far-field aberration correction. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2008; 124:3659-3668. [PMID: 19206794 DOI: 10.1121/1.3005560] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The decomposition of the time-reversal operator (DORT) is a detection and focusing technique using an array of transmit receive transducers. It can extract Green's functions of scatterers in a medium. A variant consists in transmitting focused beams (FDORT). It is shown here that the FDORT method can be interpreted as the decomposition of a time-reversal operator between an array of virtual transducers located at the transmit beams' foci and the physical array. The receive singular vectors correspond to scatterers' Green's functions expressed in the physical array while the transmit singular vectors correspond to Green's functions expressed in the virtual array. The position of the virtual array can be changed by varying the position of the foci, thus offering different points of view. Parameters and performance of some transmit schemes are discussed. Appropriately positioning the virtual transducers can simplify some problems. One application is measuring and correcting aberration in the case of a far-field phase screen model. Placing the virtual transducers near the phase screen transforms the problem in a simpler near-field phase screen problem.
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Affiliation(s)
- Jean-Luc Robert
- Philips Research North America, Briarcliff Manor, New York 10510, USA
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