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Ferraioli G, Barr RG, Berzigotti A, Sporea I, Wong VWS, Reiberger T, Karlas T, Thiele M, Cardoso AC, Ayonrinde OT, Castera L, Dietrich CF, Iijima H, Lee DH, Kemp W, Oliveira CP, Sarin SK. WFUMB Guidelines/Guidance on Liver Multiparametric Ultrasound. Part 2: Guidance on Liver Fat Quantification. ULTRASOUND IN MEDICINE & BIOLOGY 2024; 50:1088-1098. [PMID: 38658207 DOI: 10.1016/j.ultrasmedbio.2024.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/26/2024]
Abstract
The World Federation for Ultrasound in Medicine and Biology (WFUMB) has promoted the development of this document on multiparametric ultrasound. Part 2 is a guidance on the use of the available tools for the quantification of liver fat content with ultrasound. These are attenuation coefficient, backscatter coefficient, and speed of sound. All of them use the raw data of the ultrasound beam to estimate liver fat content. This guidance has the aim of helping the reader in understanding how they work and interpret the results. Confounding factors are discussed and a standardized protocol for measurement acquisition is suggested to mitigate them. The recommendations were based on published studies and experts' opinion but were not formally graded because the body of evidence remained low at the time of drafting this document.
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Affiliation(s)
- Giovanna Ferraioli
- Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy.
| | - Richard Gary Barr
- Department of Radiology, Northeastern Ohio Medical University, Youngstown, OH, USA
| | - Annalisa Berzigotti
- Department for Visceral Surgery and Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Ioan Sporea
- Department of Internal Medicine II, Division of Gastroenterology and Hepatology, Center for Advanced Research in Gastroenterology and Hepatology, "Victor Babeș" University of Medicine and Pharmacy, Timișoara, Romania
| | - Vincent Wai-Sun Wong
- Department of Medicine and Therapeutics, Medical Data Analytics Centre, The Chinese University of Hong Kong, Hong Kong, China; State Key Laboratory of Digestive Disease, Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China
| | - Thomas Reiberger
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria; Christian-Doppler Laboratory for Portal Hypertension and Liver Fibrosis, Medical University of Vienna, Vienna, Austria
| | - Thomas Karlas
- Department of Medicine II, Division of Gastroenterology, Leipzig University Medical Center, Leipzig, Germany
| | - Maja Thiele
- Center for Liver Research, Department of Gastroenterology and Hepatology, Odense University Hospital, Odense, Denmark; Department for Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Ana Carolina Cardoso
- Hepatology Division, School of Medicine, Federal University of Rio de Janeiro, Clementino, Fraga Filho Hospital, Rio de Janeiro, RJ, Brazil
| | - Oyekoya Taiwo Ayonrinde
- Department of Gastroenterology and Hepatology, Fiona Stanley Hospital, Murdoch, WA, Australia; Medical School, The University of Western Australia, Crawley, WA, Australia; Curtin Medical School, Curtin University, Bentley, WA, Australia
| | - Laurent Castera
- Université Paris-Cité, Inserm UMR1149, Centre de Recherche sur l'Inflammation, Paris, France; Service d'Hépatologie, Hôpital Beaujon, Assistance-Publique Hôpitaux de Paris, Clichy, France
| | - Christoph Frank Dietrich
- Department Allgemeine Innere Medizin (DAIM), Kliniken Hirslanden Beau Site, Salem and Permancence, Bern, Switzerland
| | - Hiroko Iijima
- Department of Gastroenterology, Division of Hepatobiliary and Pancreatic Disease, Hyogo Medical University, Nishinomiya, Hyogo, Japan; Ultrasound Imaging Center, Hyogo Medical University, Nishinomiya, Hyogo, Japan
| | - Dong Ho Lee
- Department of Radiology, College of Medicine, Seoul National University Hospital, Seoul National University, Seoul, Republic of Korea
| | - William Kemp
- Department of Gastroenterology, Alfred Hospital, Melbourne, Australia; Department of Medicine, Central Clinical School, Monash University, Melbourne, Australia
| | - Claudia P Oliveira
- Gastroenterology Department, Laboratório de Investigação (LIM07), Hospital das Clínicas de São Paulo, HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Shiv Kumar Sarin
- Department of Hepatology, Institute of Liver and Biliary Sciences, New Delhi, India
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2
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Nagaoka R, Omura M, Hasegawa H. Investigation of a method to estimate the average speed of sound using phase variances of element signals for ultrasound compound imaging. J Med Ultrason (2001) 2024; 51:17-28. [PMID: 37947986 PMCID: PMC10954954 DOI: 10.1007/s10396-023-01378-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 09/06/2023] [Indexed: 11/12/2023]
Abstract
PURPOSE In the receive beamforming of an ultrasonography system, a B-mode image is reconstructed by assuming an average speed of sound (SoS) as a constant value. In our previous studies, we proposed a method for estimating the average SoS based on the coherence factor (CF) and the reciprocal of phase variances of element signals in delay-and-sum (DAS) beamforming. In this paper, we investigate the accuracy of estimation of the average SoS for compound imaging. METHODS For this purpose, two numerical simulations were performed with k-Wave software. Also, the estimation methods based on the CF and the reciprocal were applied to in vivo data from the common carotid artery, and B-mode images were reconstructed using the estimated average SoS. RESULTS In the first numerical simulation using an inhomogeneous phantom, the relationship between the accuracy and the transmission angles for the estimation was investigated, and the root mean squared errors (RMSEs) of estimates obtained based on the CF and the reciprocal of the phase variance were 1.25 ± 0.09, and 0.765 ± 0.17% at the transmission sequence of steering angles of (- 10°, - 5°, 0°, 5°, 10°), respectively. In the second numerical simulation using a cyst phantom, lateral resolutions were improved by reconstructing the image using the estimates obtained using the proposed strategy (reciprocal). By the proposed strategy, improvement of the continuity of the lumen-intima interface in the lateral direction was observed in the in vivo experiment. CONCLUSION Consequently, the results indicated that the proposed strategy was beneficial for estimation of the average SoS and image reconstruction.
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Affiliation(s)
- Ryo Nagaoka
- Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan.
| | - Masaaki Omura
- Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan
| | - Hideyuki Hasegawa
- Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan
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Wang X, Bamber JC, Esquivel-Sirvent R, Ormachea J, Sidhu PS, Thomenius KE, Schoen S, Rosenzweig S, Pierce TT. Ultrasonic Sound Speed Estimation for Liver Fat Quantification: A Review by the AIUM-RSNA QIBA Pulse-Echo Quantitative Ultrasound Initiative. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:2327-2335. [PMID: 37550173 DOI: 10.1016/j.ultrasmedbio.2023.06.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 06/23/2023] [Accepted: 06/27/2023] [Indexed: 08/09/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a significant cause of diffuse liver disease, morbidity and mortality worldwide. Early and accurate diagnosis of NALFD is critical to identify patients at risk of disease progression. Liver biopsy is the current gold standard for diagnosis and prognosis. However, a non-invasive diagnostic tool is desired because of the high cost and risk of complications of tissue sampling. Medical ultrasound is a safe, inexpensive and widely available imaging tool for diagnosing NAFLD. Emerging sonographic tools to quantitatively estimate hepatic fat fraction, such as tissue sound speed estimation, are likely to improve diagnostic accuracy, precision and reproducibility compared with existing qualitative and semi-quantitative techniques. Various pulse-echo ultrasound speed of sound estimation methodologies have been investigated, and some have been recently commercialized. We review state-of-the-art in vivo speed of sound estimation techniques, including their advantages, limitations, technical sources of variability, biological confounders and existing commercial implementations. We report the expected range of hepatic speed of sound as a function of liver steatosis and fibrosis that may be encountered in clinical practice. Ongoing efforts seek to quantify sound speed measurement accuracy and precision to inform threshold development around meaningful differences in fat fraction and between sequential measurements.
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Affiliation(s)
- Xiaohong Wang
- Center for Ultrasound Research and Translation, Massachusetts General Hospital, Boston, MA, USA
| | - Jeffrey C Bamber
- Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, UK
| | | | | | - Paul S Sidhu
- Department of Radiology, King's College Hospital, London, UK
| | - Kai E Thomenius
- Center for Ultrasound Research and Translation, Massachusetts General Hospital, Boston, MA, USA
| | - Scott Schoen
- Center for Ultrasound Research and Translation, Massachusetts General Hospital, Boston, MA, USA
| | | | - Theodore T Pierce
- Center for Ultrasound Research and Translation, Massachusetts General Hospital, Boston, MA, USA; Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
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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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5
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Yeats E, Hall TL. Aberration correction in abdominal histotripsy. Int J Hyperthermia 2023; 40:2266594. [PMID: 37813397 PMCID: PMC10637766 DOI: 10.1080/02656736.2023.2266594] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 09/28/2023] [Indexed: 10/11/2023] Open
Abstract
In transabdominal histotripsy, ultrasound pulses are focused on the body to noninvasively destroy soft tissues via cavitation. However, the ability to focus is limited by phase aberration, or decorrelation of the ultrasound pulses due to spatial variation in the speed of sound throughout heterogeneous tissue. Phase aberration shifts, broadens, and weakens the focus, thereby reducing the safety and efficacy of histotripsy therapy. This paper reviews and discusses aberration effects in histotripsy and in related therapeutic ultrasound techniques (e.g., high intensity focused ultrasound), with an emphasis on aberration by soft tissues. Methods for aberration correction are reviewed and can be classified into two groups: model-based methods, which use segmented images of the tissue as input to an acoustic propagation model to predict and compensate phase differences, and signal-based methods, which use a receive-capable therapy array to detect phase differences by sensing acoustic signals backpropagating from the focus. The relative advantages and disadvantages of both groups of methods are discussed. Importantly, model-based methods can correct focal shift, while signal-based methods can restore substantial focal pressure, suggesting that both methods should be combined in a 2-step approach. Aberration correction will be critical to improving histotripsy treatments and expanding the histotripsy treatment envelope to enable non-invasive, non-thermal histotripsy therapy for more patients.
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Affiliation(s)
- Ellen Yeats
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States
| | - Timothy L. Hall
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States
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Preston C, Alvarez AM, Allard M, Barragan A, Witte RS. Acoustoelectric Time-Reversal for Ultrasound Phase-Aberration Correction. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2023; 70:854-864. [PMID: 37405897 PMCID: PMC10493188 DOI: 10.1109/tuffc.2023.3292595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
Acoustoelectric imaging (AEI) is a technique that combines ultrasound (US) with radio frequency recording to detect and map local current source densities. This study demonstrates a new method called acoustoelectric time reversal (AETR), which uses AEI of a small current source to correct for phase aberrations through a skull or other US-aberrating layers with applications to brain imaging and therapy. Simulations conducted at three different US frequencies (0.5, 1.5, and 2.5 MHz) were performed through media layered with different sound speeds and geometries to induce aberrations of the US beam. Time delays of the acoustoelectric (AE) signal from a monopole within the medium were calculated for each element to enable corrections using AETR. Uncorrected aberrated beam profiles were compared with those after applying AETR corrections, which demonstrated a strong recovery (29%-100%) of lateral resolution and increases in focal pressure up to 283%. To further demonstrate the practical feasibility of AETR, we further conducted bench-top experiments using a 2.5 MHz linear US array to perform AETR through 3-D-printed aberrating objects. These experiments restored lost lateral restoration up to 100% for the different aberrators and increased focal pressure up to 230% after applying AETR corrections. Cumulatively, these results highlight AETR as a powerful tool for correcting focal aberrations in the presence of a local current source with applications to AEI, US imaging, neuromodulation, and therapy.
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Ali R, Brevett T, Zhuang L, Bendjador H, Podkowa AS, Hsieh SS, Simson W, Sanabria SJ, Herickhoff CD, Dahl JJ. Aberration correction in diagnostic ultrasound: A review of the prior field and current directions. Z Med Phys 2023; 33:267-291. [PMID: 36849295 PMCID: PMC10517407 DOI: 10.1016/j.zemedi.2023.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/17/2022] [Accepted: 01/09/2023] [Indexed: 02/27/2023]
Abstract
Medical ultrasound images are reconstructed with simplifying assumptions on wave propagation, with one of the most prominent assumptions being that the imaging medium is composed of a constant sound speed. When the assumption of a constant sound speed are violated, which is true in most in vivoor clinical imaging scenarios, distortion of the transmitted and received ultrasound wavefronts appear and degrade the image quality. This distortion is known as aberration, and the techniques used to correct for the distortion are known as aberration correction techniques. Several models have been proposed to understand and correct for aberration. In this review paper, aberration and aberration correction are explored from the early models and correction techniques, including the near-field phase screen model and its associated correction techniques such as nearest-neighbor cross-correlation, to more recent models and correction techniques that incorporate spatially varying aberration and diffractive effects, such as models and techniques that rely on the estimation of the sound speed distribution in the imaging medium. In addition to historical models, future directions of ultrasound aberration correction are proposed.
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Affiliation(s)
- Rehman Ali
- Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY, USA
| | - Thurston Brevett
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Louise Zhuang
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Hanna Bendjador
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Anthony S Podkowa
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Scott S Hsieh
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Walter Simson
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Sergio J Sanabria
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA; University of Deusto/ Ikerbasque Basque Foundation for Science, Bilbao, Spain
| | - Carl D Herickhoff
- Department of Biomedical Engineering, University of Memphis, TN, USA
| | - Jeremy J Dahl
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA.
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8
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Salemi Yolgunlu P, Korta Martiartu N, Gerber UR, Frenz M, Jaeger M. Excluding Echo Shift Noise in Real-Time Pulse-Echo Speed-of-Sound Imaging. SENSORS (BASEL, SWITZERLAND) 2023; 23:5598. [PMID: 37420762 DOI: 10.3390/s23125598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/08/2023] [Accepted: 06/09/2023] [Indexed: 07/09/2023]
Abstract
Computed ultrasound tomography in echo mode (CUTE) allows real-time imaging of the tissue speed of sound (SoS) using handheld ultrasound. The SoS is retrieved by inverting a forward model that relates the spatial distribution of the tissue SoS to echo shift maps detected between varying transmit and receive angles. Despite promising results, in vivo SoS maps often show artifacts due to elevated noise in echo shift maps. To minimize artifacts, we propose a technique where an individual SoS map is reconstructed for each echo shift map separately, as opposed to a single SoS map from all echo shift maps simultaneously. The final SoS map is then obtained as a weighted average over all SoS maps. Due to the partial redundancy between different angle combinations, artifacts that appear only in a subset of the individual maps can be excluded via the averaging weights. We investigate this real-time capable technique in simulations using two numerical phantoms, one with a circular inclusion and one with two layers. Our results demonstrate that the SoS maps reconstructed using the proposed technique are equivalent to the ones using simultaneous reconstruction when considering uncorrupted data but show significantly reduced artifact level for data that are corrupted by noise.
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Affiliation(s)
- Parisa Salemi Yolgunlu
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - Naiara Korta Martiartu
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - Urs Richard Gerber
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - Martin Frenz
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - Michael Jaeger
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
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9
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van Hal VHJ, Muller JW, van Sambeek MRHM, Lopata RGP, Schwab HM. An aberration correction approach for single and dual aperture ultrasound imaging of the abdomen. ULTRASONICS 2023; 131:106936. [PMID: 36774785 DOI: 10.1016/j.ultras.2023.106936] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/20/2023] [Accepted: 01/22/2023] [Indexed: 06/18/2023]
Abstract
Abdominal ultrasound image quality is hampered by phase aberration, that is mainly caused by the large speed-of-sound (SoS) differences between fat and muscle tissue in the abdominal wall. The mismatch between the assumed and actual SoS distribution introduces general blurring of the ultrasound images, and acoustic refraction can lead to geometric distortion of the imaged features. Large aperture imaging or dual-transducer imaging can improve abdominal imaging at deep locations by providing increased contrast and resolution. However, aberration effects for large aperture imaging can be even more severe, which limits its full potential. In this study, a model-based aberration correction method for arbitrary acquisition schemes is introduced for delay-and-sum (DAS) beamforming and its performance was analyzed for both single- and dual-transducer ultrasound imaging. The method employs aberration corrected wavefront arrival times, using manually assigned local SoS values. Two wavefront models were compared. The first model is based on a straight ray approximation, and the second model on the Eikonal equation, which is solved by a multi-stencils fast marching method. Their accuracy for abdominal imaging was evaluated in acoustic simulations and phantom experiments involving tissue-mimicking and porcine material with large SoS contrast (∼100 m/s). The lateral resolution was improved by up to 90% in simulations and up to 65% in experiments compared to standard DAS, in which the use of Eikonal beamforming generally outperformed straight ray beamforming. Moreover, geometric distortions were mitigated in multi-aperture imaging, leading to a reduction in position error of around 80%. A study on the sensitivity of the aberration correction to shape and SoS of aberrating layers was performed, showing that even with imperfect segmentations or SoS values, aberration correction still outperforms standard DAS.
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Affiliation(s)
- Vera H J van Hal
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB Eindhoven, The Netherlands.
| | - Jan-Willem Muller
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB Eindhoven, The Netherlands; Department of Vascular Surgery, Catharina Hospital Eindhoven, P.O. Box 1350, 5602 ZA Eindhoven, The Netherlands.
| | - Marc R H M van Sambeek
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB Eindhoven, The Netherlands; Department of Vascular Surgery, Catharina Hospital Eindhoven, P.O. Box 1350, 5602 ZA Eindhoven, The Netherlands.
| | - Richard G P Lopata
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB Eindhoven, The Netherlands.
| | - Hans-Martin Schwab
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB Eindhoven, The Netherlands.
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10
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Ali R, Mitcham TM, Singh M, Doyley MM, Bouchard RR, Dahl JJ, Duric N. Sound Speed Estimation for Distributed Aberration Correction in Laterally Varying Media. IEEE TRANSACTIONS ON COMPUTATIONAL IMAGING 2023; 9:367-382. [PMID: 37997603 PMCID: PMC10665028 DOI: 10.1109/tci.2023.3261507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2023]
Abstract
Spatial variation in sound speed causes aberration in medical ultrasound imaging. Although our previous work has examined aberration correction in the presence of a spatially varying sound speed, practical implementations were limited to layered media due to the sound speed estimation process involved. Unfortunately, most models of layered media do not capture the lateral variations in sound speed that have the greatest aberrative effect on the image. Building upon a Fourier split-step migration technique from geophysics, this work introduces an iterative sound speed estimation and distributed aberration correction technique that can model and correct for aberrations resulting from laterally varying media. We first characterize our approach in simulations where the scattering in the media is known a-priori. Phantom and in-vivo experiments further demonstrate the capabilities of the iterative correction technique. As a result of the iterative correction scheme, point target resolution improves by up to a factor of 4 and lesion contrast improves by up to 10.0 dB in the phantom experiments presented.
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Affiliation(s)
- Rehman Ali
- Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY, USA
| | - Trevor M Mitcham
- Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY, USA
| | - Melanie Singh
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA
| | - Marvin M Doyley
- Department of Electrical Engineering, University of Rochester, Rochester, NY, USA
| | - Richard R Bouchard
- Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jeremy J Dahl
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Nebojsa Duric
- Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY, USA; Department of Electrical Engineering, University of Rochester, Rochester, NY, USA
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Yoon T, Kim Y, Awais M, Lee B. Acoustic Velocity Measurement for Enhancing Laser UltraSound Imaging Based on Time Domain Synthetic Aperture Focusing Technique. SENSORS (BASEL, SWITZERLAND) 2023; 23:2635. [PMID: 36904840 PMCID: PMC10007195 DOI: 10.3390/s23052635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
A method to enhance laser ultrasound (LUS) image reconstruction with the time-domain synthetic aperture focusing technique (T-SAFT) is presented, in which the acoustic velocity is extracted in situ with curve fitting. The operational principle is provided with the help of a numerical simulation, and the confirmation is provided experimentally. In these experiments, an all-optic LUS system was developed by using lasers for both excitation and detection of ultrasound. The acoustic velocity of a specimen was extracted in situ by fitting a hyperbolic curve to its B-scan image. The needle-like objects embedded within a polydimethylsiloxane (PDMS) block and a chicken breast have been successfully reconstructed using the extracted in situ acoustic velocity. Experimental results suggest that knowing the acoustic velocity in the T-SAFT process is important not only in finding the depth location of the target object but also for producing a high resolution image. This study is expected to pave the wave to the development and usage of all-optic LUS for bio-medical imaging.
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12
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Mast TD, Johnstone DA, Dumoulin CL, Lamba MA, Patch SK. Reconstruction of thermoacoustic emission sources induced by proton irradiation using numerical time reversal. Phys Med Biol 2023; 68:10.1088/1361-6560/acabfc. [PMID: 36595327 PMCID: PMC9976196 DOI: 10.1088/1361-6560/acabfc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Objective.Mapping of dose delivery in proton beam therapy can potentially be performed by analyzing thermoacoustic emissions measured by ultrasound arrays. Here, a method is derived and demonstrated for spatial mapping of thermoacoustic sources using numerical time reversal, simulating re-transmission of measured emissions into the medium.Approach.Spatial distributions of thermoacoustic emission sources are shown to be approximated by the analytic-signal form of the time-reversed acoustic field, evaluated at the time of the initial proton pulse. Given calibration of the array sensitivity and knowledge of tissue properties, this approach approximately reconstructs the acoustic source amplitude, equal to the product of the time derivative of the radiation dose rate, mass density, and Grüneisen parameter. This approach was implemented using two models for acoustic fields of the array elements, one modeling elements as line sources and the other as rectangular radiators. Thermoacoustic source reconstructions employed previously reported measurements of emissions from proton energy deposition in tissue-mimicking phantoms. For a phantom incorporating a bone layer, reconstructions accounted for the higher sound speed in bone. Dependence of reconstruction quality on array aperture size and signal-to-noise ratio was consistent with previous acoustic simulation studies.Main results.Thermoacoustic source distributions were successfully reconstructed from acoustic emissions measured by a linear ultrasound array. Spatial resolution of reconstructions was significantly improved in the azimuthal (array) direction by incorporation of array element diffraction. Source localization agreed well with Monte Carlo simulations of energy deposition, and was improved by incorporating effects of inhomogeneous sound speed.Significance.The presented numerical time reversal approach reconstructs thermoacoustic sources from proton beam radiation, based on straightforward processing of acoustic emissions measured by ultrasound arrays. This approach may be useful for ranging and dosimetry of clinical proton beams, if acoustic emissions of sufficient amplitude and bandwidth can be generated by therapeutic proton sources.
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Affiliation(s)
- T Douglas Mast
- Biomedical Engineering, University of Cincinnati, United States of America
| | - David A Johnstone
- Radiation Oncology, University of Cincinnati, United States of America
| | - Charles L Dumoulin
- Radiology, Cincinnati Children's Hospital Medical Center, United States of America
| | - Michael A Lamba
- Radiation Oncology, University of Cincinnati, United States of America
| | - Sarah K Patch
- Acoustic Range Estimates, Chicago, Illinois, United States of America
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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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Fetzer DT, Rosado-Mendez IM, Wang M, Robbin ML, Ozturk A, Wear KA, Ormachea J, Stiles TA, Fowlkes JB, Hall TJ, Samir AE. Pulse-Echo Quantitative US Biomarkers for Liver Steatosis: Toward Technical Standardization. Radiology 2022; 305:265-276. [PMID: 36098640 PMCID: PMC9613608 DOI: 10.1148/radiol.212808] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 04/07/2022] [Accepted: 04/14/2022] [Indexed: 11/11/2022]
Abstract
Excessive liver fat (steatosis) is now the most common cause of chronic liver disease worldwide and is an independent risk factor for cirrhosis and associated complications. Accurate and clinically useful diagnosis, risk stratification, prognostication, and therapy monitoring require accurate and reliable biomarker measurement at acceptable cost. This article describes a joint effort by the American Institute of Ultrasound in Medicine (AIUM) and the RSNA Quantitative Imaging Biomarkers Alliance (QIBA) to develop standards for clinical and technical validation of quantitative biomarkers for liver steatosis. The AIUM Liver Fat Quantification Task Force provides clinical guidance, while the RSNA QIBA Pulse-Echo Quantitative Ultrasound Biomarker Committee develops methods to measure biomarkers and reduce biomarker variability. In this article, the authors present the clinical need for quantitative imaging biomarkers of liver steatosis, review the current state of various imaging modalities, and describe the technical state of the art for three key liver steatosis pulse-echo quantitative US biomarkers: attenuation coefficient, backscatter coefficient, and speed of sound. Lastly, a perspective on current challenges and recommendations for clinical translation for each biomarker is offered.
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Affiliation(s)
| | | | - Michael Wang
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Michelle L. Robbin
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Arinc Ozturk
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Keith A. Wear
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Juvenal Ormachea
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Timothy A. Stiles
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - J. Brian Fowlkes
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Timothy J. Hall
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Anthony E. Samir
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
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16
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Yeats E, Gupta D, Xu Z, Hall TL. Effects of phase aberration on transabdominal focusing for a large aperture, low f-number histotripsy transducer. Phys Med Biol 2022; 67:10.1088/1361-6560/ac7d90. [PMID: 35772383 PMCID: PMC9396534 DOI: 10.1088/1361-6560/ac7d90] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 06/30/2022] [Indexed: 11/12/2022]
Abstract
Objective. Soft tissue phase aberration may be particularly severe for histotripsy due to large aperture and lowf-number transducer geometries. This study investigated how phase aberration from human abdominal tissue affects focusing of a large, strongly curved histotripsy transducer.Approach.A computational model (k-Wave) was experimentally validated withex vivoporcine abdominal tissue and used to simulate focusing a histotripsy transducer (radius: 14.2 cm,f-number: 0.62, central frequencyfc: 750 kHz) through the human abdomen. Abdominal computed tomography images from 10 human subjects were segmented to create three-dimensional acoustic property maps. Simulations were performed focusing at 3 target locations in the liver of each subject with ideal phase correction, without phase correction, and after separately matching the sound speed of water and fat to non-fat soft tissue.Main results.Experimental validation in porcine abdominal tissue showed that simulated and measured arrival time differences agreed well (average error, ∼0.10 acoustic cycles atfc). In simulations with human tissue, aberration created arrival time differences of 0.65μs (∼0.5 cycles) at the target and shifted the focus from the target by 6.8 mm (6.4 mm pre-focally along depth direction), on average. Ideal phase correction increased maximum pressure amplitude by 95%, on average. Matching the sound speed of water and fat to non-fat soft tissue decreased the average pre-focal shift by 3.6 and 0.5 mm and increased pressure amplitude by 2% and 69%, respectively.Significance.Soft tissue phase aberration of large aperture, lowf-number histotripsy transducers is substantial despite low therapeutic frequencies. Phase correction could potentially recover substantial pressure amplitude for transabdominal histotripsy. Additionally, different heterogeneity sources distinctly affect focusing quality. The water path strongly affects the focal shift, while irregular tissue boundaries (e.g. fat) dominate pressure loss.
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Affiliation(s)
- Ellen Yeats
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, United States of America
| | - Dinank Gupta
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, United States of America
| | - Zhen Xu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, United States of America
| | - Timothy L Hall
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, United States of America
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Ali R, Brevett T, Hyun D, Brickson LL, Dahl JJ. Distributed Aberration Correction Techniques Based on Tomographic Sound Speed Estimates. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:1714-1726. [PMID: 35353699 PMCID: PMC9164761 DOI: 10.1109/tuffc.2022.3162836] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Phase aberration is widely considered a major source of image degradation in medical pulse-echo ultrasound. Traditionally, near-field phase aberration correction techniques are unable to account for distributed aberrations due to a spatially varying speed of sound in the medium, while most distributed aberration correction techniques require the use of point-like sources and are impractical for clinical applications where diffuse scattering is dominant. Here, we present two distributed aberration correction techniques that utilize sound speed estimates from a tomographic sound speed estimator that builds on our previous work with diffuse scattering in layered media. We first characterize the performance of our sound speed estimator and distributed aberration correction techniques in simulations where the scattering in the media is known a priori. Phantom and in vivo experiments further demonstrate the capabilities of the sound speed estimator and the aberration correction techniques. In phantom experiments, point target resolution improves from 0.58 to 0.26 and 0.27 mm, and lesion contrast improves from 17.7 to 23.5 and 25.9 dB, as a result of distributed aberration correction using the eikonal and wavefield correlation techniques, respectively.
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18
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Ormachea J, Parker KJ. A Preliminary Study of Liver Fat Quantification Using Reported Ultrasound Speed of Sound and Attenuation Parameters. ULTRASOUND IN MEDICINE & BIOLOGY 2022; 48:675-684. [PMID: 35039191 DOI: 10.1016/j.ultrasmedbio.2021.12.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
The quantification of liver fat as a diagnostic assessment of steatosis remains an important priority for non-invasive imaging systems. We derive a framework in which the unknown fat volume percentage can be estimated from a pair of ultrasound measurements. The precise estimation of ultrasound speed of sound and attenuation within the liver is found to be sufficient for estimating fat volume assuming a classic model of the properties of a composite elastic material. In this model, steatosis is represented as a random dispersion of spherical fat vacuoles with acoustic properties similar to those of edible oils. Using values of speed of sound and attenuation from the literature in which normal and steatotic livers were studied near 3.5 MHz, we describe agreement of the new estimation method with independent measures of fat. This framework holds the potential for translation to clinical scanners with which the two ultrasound measurements can be made and used for improved quantitative assessment of steatosis.
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Affiliation(s)
- Juvenal Ormachea
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, USA
| | - Kevin J Parker
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, USA.
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Ali R, Telichko AV, Wang H, Sukumar UK, Vilches-Moure JG, Paulmurugan R, Dahl JJ. Local Sound Speed Estimation for Pulse-Echo Ultrasound in Layered Media. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:500-511. [PMID: 34723801 PMCID: PMC9127706 DOI: 10.1109/tuffc.2021.3124479] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Our previous methodology in local sound speed estimation utilized time delays measured by the cross correlation of delayed full-synthetic aperture channel data to estimate the average speed of sound. However, focal distortions in this methodology lead to biased estimates of the average speed of sound, which, in turn, leads to biased estimates of the local speed of sound. Here, we demonstrate the bias in the previous methodology and introduce a coherence-based average sound speed estimator that eliminates this bias and is computationally much cheaper in practice. Because this coherence-based approach estimates the average sound speed in the medium over an equally spaced grid in depth rather than time, we derive a refined model that relates the local and average speeds of sound as a function of depth in layered media. A fast, closed-form inversion of this model yields highly accurate local sound speed estimates. The root-mean-square (rms) error of local sound speed reconstruction in simulations of two-layer media is 4.6 and 2.5 m/s at 4 and 8 MHz, respectively. This work examines the impact of frequency, f -number, aberration, and reverberation on sound speed estimation. Phantom and in vivo experiments in rats further validate the coherence-based sound speed estimator.
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20
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Jeon S, Choi W, Park B, Kim C. A Deep Learning-Based Model That Reduces Speed of Sound Aberrations for Improved In Vivo Photoacoustic Imaging. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2021; 30:8773-8784. [PMID: 34665732 DOI: 10.1109/tip.2021.3120053] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Photoacoustic imaging (PAI) has attracted great attention as a medical imaging method. Typically, photoacoustic (PA) images are reconstructed via beamforming, but many factors still hinder the beamforming techniques in reconstructing optimal images in terms of image resolution, imaging depth, or processing speed. Here, we demonstrate a novel deep learning PAI that uses multiple speed of sound (SoS) inputs. With this novel method, we achieved SoS aberration mitigation, streak artifact removal, and temporal resolution improvement all at once in structural and functional in vivo PA images of healthy human limbs and melanoma patients. The presented method produces high-contrast PA images in vivo with reduced distortion, even in adverse conditions where the medium is heterogeneous and/or the data sampling is sparse. Thus, we believe that this new method can achieve high image quality with fast data acquisition and can contribute to the advance of clinical PAI.
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21
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Rau R, Schweizer D, Vishnevskiy V, Goksel O. Speed-of-sound imaging using diverging waves. Int J Comput Assist Radiol Surg 2021; 16:1201-1211. [PMID: 34160749 PMCID: PMC8260432 DOI: 10.1007/s11548-021-02426-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/28/2021] [Indexed: 10/29/2022]
Abstract
PURPOSE Due to its safe, low-cost, portable, and real-time nature, ultrasound is a prominent imaging method in computer-assisted interventions. However, typical B-mode ultrasound images have limited contrast and tissue differentiation capability for several clinical applications. METHODS Recent introduction of imaging speed-of-sound (SoS) in soft tissues using conventional ultrasound systems and transducers has great potential in clinical translation providing additional imaging contrast, e.g., in intervention planning, navigation, and guidance applications. However, current pulse-echo SoS imaging methods relying on plane wave (PW) sequences are highly prone to aberration effects, therefore suboptimal in image quality. In this paper we propose using diverging waves (DW) for SoS imaging and study this comparatively to PW. RESULTS We demonstrate wavefront aberration and its effects on the key step of displacement tracking in the SoS reconstruction pipeline, comparatively between PW and DW on a synthetic example. We then present the parameterization sensitivity of both approaches on a set of simulated phantoms. Analyzing SoS imaging performance comparatively indicates that using DW instead of PW, the reconstruction accuracy improves by over 20% in root-mean-square-error (RMSE) and by 42% in contrast-to-noise ratio (CNR). We then demonstrate SoS reconstructions with actual US acquisitions of a breast phantom. With our proposed DW, CNR for a high contrast tumor-representative inclusion is improved by 42%, while for a low contrast cyst-representative inclusion a 2.8-fold improvement is achieved. CONCLUSION SoS imaging, so far only studied using a plane wave transmission scheme, can be made more reliable and accurate using DW. The high imaging contrast of DW-based SoS imaging will thus facilitate the clinical translation of the method and utilization in computer-assisted interventions such as ultrasound-guided biopsies, where B-Mode contrast is often to low to detect potential lesions.
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Affiliation(s)
- Richard Rau
- Computer-assisted Applications in Medicine group, ETH Zurich, Zurich, Switzerland
| | - Dieter Schweizer
- Computer-assisted Applications in Medicine group, ETH Zurich, Zurich, Switzerland
| | - Valery Vishnevskiy
- Computer-assisted Applications in Medicine group, ETH Zurich, Zurich, Switzerland
| | - Orcun Goksel
- Computer-assisted Applications in Medicine group, ETH Zurich, Zurich, Switzerland
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Advances in ultrasonography: image formation and quality assessment. J Med Ultrason (2001) 2021; 48:377-389. [PMID: 34669073 PMCID: PMC8578163 DOI: 10.1007/s10396-021-01140-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 08/17/2021] [Indexed: 01/01/2023]
Abstract
Delay-and-sum (DAS) beamforming is widely used for generation of B-mode images from echo signals obtained with an array probe composed of transducer elements. However, the resolution and contrast achieved with DAS beamforming are determined by the physical specifications of the array, e.g., size and pitch of elements. To overcome this limitation, adaptive imaging methods have recently been explored extensively thanks to the dissemination of digital and programmable ultrasound systems. On the other hand, it is also important to evaluate the performance of such adaptive imaging methods quantitatively to validate whether the modification of the image characteristics resulting from the developed method is appropriate. Since many adaptive imaging methods have been developed and they often alter image characteristics, attempts have also been made to update the methods for quantitative assessment of image quality. This article provides a review of recent developments in adaptive imaging and image quality assessment.
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23
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Yamaguchi T. Basic concept and clinical applications of quantitative ultrasound (QUS) technologies. J Med Ultrason (2001) 2021; 48:391-402. [PMID: 34669072 PMCID: PMC8578064 DOI: 10.1007/s10396-021-01139-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 07/26/2021] [Indexed: 01/01/2023]
Abstract
In the field of clinical ultrasound, the full digitalization of diagnostic equipment in the 2000s enabled the technological development of quantitative ultrasound (QUS), followed by multiple diagnostic technologies that have been put into practical use in recent years. In QUS, tissue characteristics are quantified and parameters are calculated by analyzing the radiofrequency (RF) echo signals returning to the transducer. However, the physical properties (and pathological level structure) of the biological tissues responsible for the imaging features and QUS parameters have not been sufficiently verified as there are various conditions for observing living tissue with ultrasound and inevitable discrepancies between theoretical and actual measurements. A major issue of QUS in clinical application is that the evaluation results depend on the acquisition conditions of the RF echo signal as the source of the image information, and also vary according to the model of the diagnostic device. In this paper, typical examples of QUS techniques for evaluating attenuation, speed of sound, amplitude envelope characteristics, and backscatter coefficient in living tissues are introduced. Exemplary basic research and clinical applications related to these technologies, and initiatives currently being undertaken to establish the QUS method as a true tissue characterization technology, are also discussed.
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Affiliation(s)
- Tadashi Yamaguchi
- grid.136304.30000 0004 0370 1101Center for Frontier Medical Engineering, Chiba University, 1-33 Yayoicho, Inage, Chiba 2638522 Japan
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24
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Bernhardt M, Vishnevskiy V, Rau R, Goksel O. Training Variational Networks With Multidomain Simulations: Speed-of-Sound Image Reconstruction. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2020; 67:2584-2594. [PMID: 32746211 DOI: 10.1109/tuffc.2020.3010186] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Speed-of-sound (SoS) has been shown as a potential biomarker for breast cancer imaging, successfully differentiating malignant tumors from benign ones. SoS images can be reconstructed from time-of-flight measurements from ultrasound images acquired using conventional handheld ultrasound transducers. Variational networks (VNs) have recently been shown to be a potential learning-based approach for optimizing inverse problems in image reconstruction. Despite earlier promising results, these methods, however, do not generalize well from simulated to acquired data, due to the domain shift. In this work, we present for the first time a VN solution for a pulse-echo SoS image reconstruction problem using diverging waves with conventional transducers and single-sided tissue access. This is made possible by incorporating simulations with varying complexity into training. We use loop unrolling of gradient descent with momentum, with an exponentially weighted loss of outputs at each unrolled iteration in order to regularize the training. We learn norms as activation functions regularized to have smooth forms for robustness to input distribution variations. We evaluate reconstruction quality on the ray-based and full-wave simulations as well as on the tissue-mimicking phantom data, in comparison with a classical iterative [limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS)] optimization of this image reconstruction problem. We show that the proposed regularization techniques combined with multisource domain training yield substantial improvements in the domain adaptation capabilities of VN, reducing the median root mean squared error (RMSE) by 54% on a wave-based simulation data set compared to the baseline VN. We also show that on data acquired from a tissue-mimicking breast phantom, the proposed VN provides improved reconstruction in 12 ms.
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Stähli P, Kuriakose M, Frenz M, Jaeger M. Improved forward model for quantitative pulse-echo speed-of-sound imaging. ULTRASONICS 2020; 108:106168. [PMID: 32502892 DOI: 10.1016/j.ultras.2020.106168] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 02/24/2020] [Accepted: 04/24/2020] [Indexed: 05/24/2023]
Abstract
Computed ultrasound tomography in echo mode (CUTE) allows determining the spatial distribution of speed-of-sound (SoS) inside tissue using handheld pulse-echo ultrasound (US). This technique is based on measuring the changing phase of beamformed echoes obtained under varying transmit (Tx) and/or receive (Rx) steering angles. The SoS is reconstructed by inverting a forward model describing how the spatial distribution of SoS is related to the spatial distribution of the echo phase shift. Thanks to the straight-ray approximation, this forward model is linear and can be inverted in real-time when implemented in a state-of-the art system. Here we demonstrate that the forward model must contain two features that were not taken into account so far: (a) the phase shift must be detected between pairs of Tx and Rx angles that are centred around a set of common mid-angles, and (b) it must account for an additional phase shift induced by the offset of the reconstructed position of echoes. In a phantom study mimicking hepatic and cancer imaging, we show that both features are required to accurately predict echo phase shift among different phantom geometries, and that substantially improved quantitative SoS images are obtained compared to the model that has been used so far. The importance of the new model is corroborated by a preliminary volunteer result.
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Affiliation(s)
- Patrick Stähli
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - Maju Kuriakose
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - Martin Frenz
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland.
| | - Michael Jaeger
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
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26
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Renaud G, Clouzet P, Cassereau D, Talmant M. Measuring anisotropy of elastic wave velocity with ultrasound imaging and an autofocus method: application to cortical bone. ACTA ACUST UNITED AC 2020; 65:235016. [DOI: 10.1088/1361-6560/abb92c] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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27
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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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28
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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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29
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Rodriguez-Molares A, Rindal OMH, D'hooge J, Masoy SE, Austeng A, Lediju Bell MA, Torp H. The Generalized Contrast-to-Noise Ratio: A Formal Definition for Lesion Detectability. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2020; 67:745-759. [PMID: 31796398 PMCID: PMC8354776 DOI: 10.1109/tuffc.2019.2956855] [Citation(s) in RCA: 151] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In the last 30 years, the contrast-to-noise ratio (CNR) has been used to estimate the contrast and lesion detectability in ultrasound images. Recent studies have shown that the CNR cannot be used with modern beamformers, as dynamic range alterations can produce arbitrarily high CNR values with no real effect on the probability of lesion detection. We generalize the definition of CNR based on the overlap area between two probability density functions. This generalized CNR (gCNR) is robust against dynamic range alterations; it can be applied to all kind of images, units, or scales; it provides a quantitative measure for contrast; and it has a simple statistical interpretation, i.e., the success rate that can be expected from an ideal observer at the task of separating pixels. We test gCNR on several state-of-the-art imaging algorithms and, in addition, on a trivial compression of the dynamic range. We observe that CNR varies greatly between the state-of-the-art methods, with improvements larger than 100%. We observe that trivial compression leads to a CNR improvement of over 200%. The proposed index, however, yields the same value for compressed and uncompressed images. The tested methods showed mismatched performance in terms of lesion detectability, with variations in gCNR ranging from -0.08 to +0.29. This new metric fixes a methodological flaw in the way we study contrast and allows us to assess the relevance of new imaging algorithms.
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30
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Podkowa AS, Oelze ML. The convolutional interpretation of registration-based plane wave steered pulse-echo local sound speed estimators. Phys Med Biol 2020; 65:025003. [PMID: 31822647 DOI: 10.1088/1361-6560/ab6071] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Pulse-echo reconstruction of sound speed has long been considered a difficult problem within the domain of quantitative biomedical ultrasound. However, recent results (Jaeger 2015 Ultrasound Med. Biol. 41 235-50; Jaeger and Frenz 2015 Ultrasonics 62 299-304; Jaeger et al 2015 Phys. Med. Biol. 60 4497-515) have demonstrated that pulse-echo reconstructions of sound speed are achievable by exploiting correlations in post-beamformed data from steered, plane-wave excitations in the presence of diffuse scatterers. Despite these recent advances, a coherent theoretical imaging framework for describing the approach and results is lacking in the literature. In this work, the problem of sound speed reconstruction using steered, plane-wave excitations is reformulated as a truncated convolutional problem, and the theoretical implications of this reformulation are explored. Additionally, a matrix-free algorithm is proposed that leverages the computational and storage advantages of the fast Fourier transform (FFT) while simultaneously avoiding FFT wraparound artifacts. In particular, the storage constraints of the approach are reduced down from [Formula: see text] to [Formula: see text] over full matrix reconstruction, making this approach a better candidate for large reconstructions on clinical machines. This algorithm was then tested in the open source simulation package k-Wave to assess its robustness to modeling error and resolution reduction was demonstrated under full-wave propagation conditions relative to ideal straight-ray simulations. The method was also validated in a phantom experiment.
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31
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Receive Beam-Steering and Clutter Reduction for Imaging the Speed-of-Sound Inside the Carotid Artery. J Imaging 2018. [DOI: 10.3390/jimaging4120145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Handheld imaging of the tissue’s speed-of-sound (SoS) is a promising multimodal addition to diagnostic ultrasonography for the examination of tissue composition. Computed ultrasound tomography in echo mode (CUTE) probes the spatial distribution of SoS, conventionally via scanning the tissue under a varying angle of ultrasound transmission, and quantifying—in a spatially resolved way—phase variations of the beamformed echoes. So far, this technique is not applicable to imaging the lumen of vessels, where blood flow and tissue clutter inhibit phase tracking of the blood echoes. With the goal to enable the assessment of atherosclerotic plaque composition inside the carotid artery, we propose two modifications to CUTE: (a) use receive (Rx) beam-steering as opposed to transmit (Tx) beam-steering to increase acquisition speed and to reduce flow-related phase decorrelation, and (b) conduct pairwise subtraction of data obtained from repetitions of the scan sequence, to highlight blood echoes relative to static echo clutter and thus enable the phase tracking of blood echoes. These modifications were tested in a phantom study, where the echogenicity of the vessel lumen was chosen to be similar to the one of the background medium, which allows a direct comparison of SoS images obtained with the different techniques. Our results demonstrate that the combination of Rx-steering with the subtraction technique results in an SoS image of the same quality as obtained with conventional Tx-steering. Together with the improved acquisition speed, this makes the proposed technique a key step towards successful imaging of the SoS inside the carotid artery.
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32
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Arabul MU, Heres HM, Rutten MCM, van Sambeek MRHM, van de Vosse FN, Lopata RGP. Investigation on the Effect of Spatial Compounding on Photoacoustic Images of Carotid Plaques in the In Vivo Available Rotational Range. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2018; 65:440-447. [PMID: 29505410 DOI: 10.1109/tuffc.2018.2792903] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Photoacoustic imaging (PAI) is a promising imaging modality due to its high optical specificity. However, the low signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of in vivo PA images are major challenges that prevent PAI from finding its place in clinics. This paper investigates the merit of spatial compounding of PA images in arterial phantoms and the achievable improvements of SNR, when in vivo conditions are mimicked. The analysis of the compounding technique was performed on a polyvinyl alcohol vessel phantom with black threads embedded in its wall. The in vivo conditions were mimicked by limiting the rotation range in ±30°, adding turbid surrounding medium, and filling the lumen with porcine blood. Finally, the performance of the technique was evaluated in ex vivo human carotid plaque samples. Results showed that spatial compounding elevates the SNR by 5-10 dB and CNR by 1-5 dB, depending on the location of the absorbers. This paper elucidates prospective in vivo PA characterization of carotid plaques by proposing a method to enhance PA image quality.
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33
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He X. Sound speed optimization based on fuzzy sets using image texture as quality factors. BIO WEB OF CONFERENCES 2017. [DOI: 10.1051/bioconf/20170803014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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