Ultrafast Ultrasound Imaging

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Acoustics and Vibrations".

Deadline for manuscript submissions: closed (9 March 2018) | Viewed by 52063

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Special Issue Editors

Graduate School of Science and Engineering for Research, University of Toyama, 3190 Gofuku, Toyama, Toyama Prefecture 930-8555, Japan
Interests: ultrasonic beamforming; ultrasonic signal processing; functional ultrasound imaging
Medical Ultrasound Imaging Center, Radboud University Medical Centre, Nijmegen, The Netherlands
Interests: ultrasound functional imaging; quantitative ultrasound; photoacoustic imaging

Special Issue Information

Dear Colleagues,

Ultrafast ultrasound is becoming an indispensable technique for functional ultrasonic imaging, such as transient elastography, blood flow imaging, high-intensity focused ultrasound (HIFU) monitoring, etc. On the other hand, to compensate for the limitations and weaknesses of ultrafast ultrasound imaging, such as lower resolution and contrast relative to conventional ultrasound imaging, further developments are highly demanded for enhancing the performance and applicability of ultrafast ultrasound imaging. We welcome your contributions to this Special Issue on any of the topics related to “Ultrafast Ultrasound Imaging”.

Prof. Dr. Hideyuki Hasegawa
Prof. Dr. Chris L. de Korte
Guest Editors

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Keywords

  • Imaging and signal processing methods
  • Blood flow imaging
  • Contrast agents
  • Elastography
  • Medical photoacoustics
  • Therapeutic monitoring

Published Papers (12 papers)

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Editorial

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4 pages, 161 KiB  
Editorial
Special Issue on Ultrafast Ultrasound Imaging and Its Applications
by Hideyuki Hasegawa and Chris L. De Korte
Appl. Sci. 2018, 8(7), 1110; https://doi.org/10.3390/app8071110 - 10 Jul 2018
Cited by 3 | Viewed by 2505
Abstract
Among medical imaging modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), ultrasound imaging stands out in terms of temporal resolution[…] Full article
(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)

Research

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16 pages, 8395 KiB  
Article
Iterative 2D Tissue Motion Tracking in Ultrafast Ultrasound Imaging
by John Albinsson, Hideyuki Hasegawa, Hiroki Takahashi, Enrico Boni, Alessandro Ramalli, Åsa Rydén Ahlgren and Magnus Cinthio
Appl. Sci. 2018, 8(5), 662; https://doi.org/10.3390/app8050662 - 25 Apr 2018
Cited by 7 | Viewed by 3143
Abstract
In order to study longitudinal movement and intramural shearing of the arterial wall with a Lagrangian viewpoint using ultrafast ultrasound imaging, a new tracking scheme is required. We propose the use of an iterative tracking scheme based on temporary down-sampling of the frame-rate, [...] Read more.
In order to study longitudinal movement and intramural shearing of the arterial wall with a Lagrangian viewpoint using ultrafast ultrasound imaging, a new tracking scheme is required. We propose the use of an iterative tracking scheme based on temporary down-sampling of the frame-rate, anteroposterior tracking, and unbiased block-matching using two kernels per position estimate. The tracking scheme was evaluated on phantom B-mode cine loops and considered both velocity and displacement for a range of down-sampling factors (k = 1–128) at the start of the iterations. The cine loops had a frame rate of 1300–1500 Hz and were beamformed using delay-and-sum. The evaluation on phantom showed that both the mean estimation errors and the standard deviations decreased with an increasing initial down-sampling factor, while they increased with an increased velocity or larger pitch. A limited in vivo study shows that the major pattern of movement corresponds well with state-of-the-art low frame rate motion estimates, indicating that the proposed tracking scheme could enable the study of longitudinal movement of the intima–media complex using ultrafast ultrasound imaging, and is one step towards estimating the propagation velocity of the longitudinal movement of the arterial wall. Full article
(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)
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18 pages, 32924 KiB  
Article
Multi-Plane Ultrafast Compound 3D Strain Imaging: Experimental Validation in a Carotid Bifurcation Phantom
by Stein Fekkes, Anne E. C. M. Saris, Jan Menssen, Maartje M. Nillesen, Hendrik H. G. Hansen and Chris L. De Korte
Appl. Sci. 2018, 8(4), 637; https://doi.org/10.3390/app8040637 - 20 Apr 2018
Cited by 7 | Viewed by 4139
Abstract
Strain imaging of the carotid artery (CA) has demonstrated to be a technique capable of identifying plaque composition. This study assesses the performance of volumetric strain imaging derived from multi-plane acquisitions with a single transducer, with and without displacement compounding. These methods were [...] Read more.
Strain imaging of the carotid artery (CA) has demonstrated to be a technique capable of identifying plaque composition. This study assesses the performance of volumetric strain imaging derived from multi-plane acquisitions with a single transducer, with and without displacement compounding. These methods were compared to a reference method using two orthogonally placed transducers. A polyvinyl alcohol phantom was created resembling a stenotic CA bifurcation. A realistic pulsatile flow was imposed on the phantom, resulting in fluid pressures inducing 10% strains. Two orthogonally aligned linear array transducers were connected to two Verasonics systems and fixed in a translation stage. For 120 equally spaced elevational positions, ultrasound series were acquired for a complete cardiac cycle and synchronized using a trigger. Each series consisted of ultrafast plane-wave acquisitions at 3 alternating angles. Inter-frame displacements were estimated using a 3D cross-correlation-based tracking algorithm. Horizontal displacements were acquired using the single probe lateral displacement estimate, the single probe compounded by axial displacement estimates obtained at angles of 19.47 and −19.47 degrees, and the dual probe registered axial displacement estimate. After 3D tracking, least squares strain estimations were performed to compare compressive and tensile principal strains in 3D for all methods. The compounding technique clearly outperformed the zero-degree method for the complete cardiac cycle and resulted in more accurate 3D strain estimates. Full article
(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)
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19 pages, 6826 KiB  
Article
A PSF-Shape-Based Beamforming Strategy for Robust 2D Motion Estimation in Ultrafast Data
by Anne E. C. M. Saris, Stein Fekkes, Maartje M. Nillesen, Hendrik H. G. Hansen and Chris L. De Korte
Appl. Sci. 2018, 8(3), 429; https://doi.org/10.3390/app8030429 - 13 Mar 2018
Cited by 12 | Viewed by 3415
Abstract
This paper presents a framework for motion estimation in ultrafast ultrasound data. It describes a novel approach for determining the sampling grid for ultrafast data based on the system’s point-spread-function (PSF). As a consequence, the cross-correlation functions (CCF) used in the speckle tracking [...] Read more.
This paper presents a framework for motion estimation in ultrafast ultrasound data. It describes a novel approach for determining the sampling grid for ultrafast data based on the system’s point-spread-function (PSF). As a consequence, the cross-correlation functions (CCF) used in the speckle tracking (ST) algorithm will have circular-shaped peaks, which can be interpolated using a 2D interpolation method to estimate subsample displacements. Carotid artery wall motion and parabolic blood flow simulations together with rotating disk experiments using a Verasonics Vantage 256 are used for performance evaluation. Zero-degree plane wave data were acquired using an ATL L5-12 (fc = 9 MHz) transducer for a range of pulse repetition frequencies (PRFs), resulting in 0–600 µm inter-frame displacements. The proposed methodology was compared to data beamformed on a conventionally spaced grid, combined with the commonly used 1D parabolic interpolation. The PSF-shape-based beamforming grid combined with 2D cubic interpolation showed the most accurate and stable performance with respect to the full range of inter-frame displacements, both for the assessment of blood flow and vessel wall dynamics. The proposed methodology can be used as a protocolled way to beamform ultrafast data and obtain accurate estimates of tissue motion. Full article
(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)
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16 pages, 5443 KiB  
Article
Quasi-Static Elastography and Ultrasound Plane-Wave Imaging: The Effect of Beam-Forming Strategies on the Accuracy of Displacement Estimations
by Gijs A.G.M. Hendriks, Chuan Chen, Hendrik H.G. Hansen and Chris L. De Korte
Appl. Sci. 2018, 8(3), 319; https://doi.org/10.3390/app8030319 - 26 Feb 2018
Cited by 9 | Viewed by 4208
Abstract
Quasi-static elastography is an ultrasound method which is widely used to assess displacements and strain in tissue by correlating ultrasound data at different levels of deformation. Ultrafast plane-wave imaging allows us to obtain ultrasound data at frame rates over 10 kHz, permitting the [...] Read more.
Quasi-static elastography is an ultrasound method which is widely used to assess displacements and strain in tissue by correlating ultrasound data at different levels of deformation. Ultrafast plane-wave imaging allows us to obtain ultrasound data at frame rates over 10 kHz, permitting the quantification and visualization of fast deformations. Currently, mainly three beam-forming strategies are used to reconstruct radio frequency (RF) data from plane-wave acquisitions: delay-and-sum (DaS), and Lu’s-fk and Stolt’s-fk operating in the temporal-spatial and Fourier spaces, respectively. However, the effect of these strategies on elastography is unknown. This study investigates the effect of these beam-forming strategies on the accuracy of displacement estimation in four transducers (L7-4, 12L4VF, L12-5, MS250) for various reconstruction line densities and apodization/filtering settings. A method was developed to assess the accuracy experimentally using displacement gradients obtained in a rotating phantom. A line density with multiple lines per pitch resulted in increased accuracy compared to one line per pitch for all transducers and strategies. The impact on displacement accuracy of apodization/filtering varied per transducer. Overall, Lu’s-fk beam-forming resulted in the most accurate displacement estimates. Although DaS in some cases provided similar results, Lu’s-fk is more computationally efficient, leading to the conclusion that Lu’s-fk is most optimal for plane wave ultrasound-based elastography. Full article
(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)
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16 pages, 8657 KiB  
Article
High-Frame-Rate Doppler Ultrasound Using a Repeated Transmit Sequence
by Anthony S. Podkowa, Michael L. Oelze and Jeffrey A. Ketterling
Appl. Sci. 2018, 8(2), 227; https://doi.org/10.3390/app8020227 - 01 Feb 2018
Cited by 13 | Viewed by 3965
Abstract
The maximum detectable velocity of high-frame-rate color flow Doppler ultrasound is limited by the imaging frame rate when using coherent compounding techniques. Traditionally, high quality ultrasonic images are produced at a high frame rate via coherent compounding of steered plane wave reconstructions. However, [...] Read more.
The maximum detectable velocity of high-frame-rate color flow Doppler ultrasound is limited by the imaging frame rate when using coherent compounding techniques. Traditionally, high quality ultrasonic images are produced at a high frame rate via coherent compounding of steered plane wave reconstructions. However, this compounding operation results in an effective downsampling of the slow-time signal, thereby artificially reducing the frame rate. To alleviate this effect, a new transmit sequence is introduced where each transmit angle is repeated in succession. This transmit sequence allows for direct comparison between low resolution, pre-compounded frames at a short time interval in ways that are resistent to sidelobe motion. Use of this transmit sequence increases the maximum detectable velocity by a scale factor of the transmit sequence length. The performance of this new transmit sequence was evaluated using a rotating cylindrical phantom and compared with traditional methods using a 15-MHz linear array transducer. Axial velocity estimates were recorded for a range of ± 300 mm/s and compared to the known ground truth. Using these new techniques, the root mean square error was reduced from over 400 mm/s to below 50 mm/s in the high-velocity regime compared to traditional techniques. The standard deviation of the velocity estimate in the same velocity range was reduced from 250 mm/s to 30 mm/s. This result demonstrates the viability of the repeated transmit sequence methods in detecting and quantifying high-velocity flow. Full article
(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)
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13 pages, 2913 KiB  
Article
Adaptive Beamformer Combined with Phase Coherence Weighting Applied to Ultrafast Ultrasound
by Michiya Mozumi and Hideyuki Hasegawa
Appl. Sci. 2018, 8(2), 204; https://doi.org/10.3390/app8020204 - 30 Jan 2018
Cited by 16 | Viewed by 3854
Abstract
Ultrafast ultrasound imaging is a promising technique for measurement of fast moving objects. In ultrafast ultrasound imaging, the high temporal resolution is realized at the expense of the lateral spatial resolution and image contrast. The lateral resolution and image contrast are important factors [...] Read more.
Ultrafast ultrasound imaging is a promising technique for measurement of fast moving objects. In ultrafast ultrasound imaging, the high temporal resolution is realized at the expense of the lateral spatial resolution and image contrast. The lateral resolution and image contrast are important factors determining the quality of a B-mode image, and methods for improvements of the lateral resolution and contrast have been developed. In the present study, we focused on two signal processing techniques; one is an adaptive beamformer, and the other is the phase coherence factor (PCF). By weighting the output of the modified amplitude and phase estimation (mAPES) beamformer by the phase coherence factor, image quality was expected to be improved. In the present study, we investigated how to implement the PCF into the mAPES beamformer. In one of the two examined strategies, the PCF is estimated using element echo signals before application of the weight vector determined by the adaptive beamformer. In the other strategy, the PCF was evaluated from the element signals subjected to the mAPES beamformer weights. The performance of the proposed method was evaluated by the experiments using an ultrasonic imaging phantom. Using the proposed strategies, the lateral full widths at half maximum (FWHM) were both 0.288 mm, which was better than that of 0.348 mm obtained by the mAPES beamformer only. Also, the image contrasts realized by the mAPES beamformer with the PCFs estimated before and after application of the mAPES beamformer weights to the element signals were 5.61 dB and 5.32 dB, respectively, which were better than that of 5.14 dB obtained by the mAPES beamformer only. Full article
(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)
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15 pages, 9576 KiB  
Article
Fast Volumetric Ultrasound B-Mode and Doppler Imaging with a New High-Channels Density Platform for Advanced 4D Cardiac Imaging/Therapy
by Lorena Petrusca, François Varray, Rémi Souchon, Adeline Bernard, Jean-Yves Chapelon, Hervé Liebgott, William Apoutou N’Djin and Magalie Viallon
Appl. Sci. 2018, 8(2), 200; https://doi.org/10.3390/app8020200 - 29 Jan 2018
Cited by 54 | Viewed by 7437
Abstract
A novel ultrasound (US) high-channels platform is a pre-requisite to open new frontiers in diagnostic and/or therapy by experimental implementation of innovative advanced US techniques. To date, a few systems with more than 1000 transducers permit full and simultaneous control in both transmission [...] Read more.
A novel ultrasound (US) high-channels platform is a pre-requisite to open new frontiers in diagnostic and/or therapy by experimental implementation of innovative advanced US techniques. To date, a few systems with more than 1000 transducers permit full and simultaneous control in both transmission and receiving of all single elements of arrays. A powerful US platform for implementing 4-D (real-time 3-D) advanced US strategies, offering full research access, is presented in this paper. It includes a 1024-elements array prototype designed for 4-D cardiac dual-mode US imaging/therapy and 4 synchronized Vantage systems. The physical addressing of each element was properly chosen for allowing various array downsampled combinations while minimizing the number of driving systems. Numerical simulations of US imaging were performed, and corresponding experimental data were acquired to compare full and downsampled array strategies, testing 4-D imaging sequences and reconstruction processes. The results indicate the degree of degradation of image quality when using full array or downsampled combinations, and the contrast ratio and the contrast to noise ratio vary from 7.71 dB to 2.02 dB and from 2.99 dB to −7.31 dB, respectively. Moreover, the feasibility of the 4-D US platform implementation was tested on a blood vessel mimicking phantom for preliminary Doppler applications. The acquired data with fast volumetric imaging with up to 2000 fps allowed assessing the validity of common 3-D power Doppler, opening in this way a large field of applications. Full article
(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)
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7068 KiB  
Article
Contrast-Enhanced Ultrasound Imaging Based on Bubble Region Detection
by Yurong Huang, Jinhua Yu, Yusheng Tong, Shuying Li, Liang Chen, Yuanyuan Wang and Qi Zhang
Appl. Sci. 2017, 7(10), 1098; https://doi.org/10.3390/app7101098 - 24 Oct 2017
Cited by 4 | Viewed by 4201
Abstract
The study of ultrasound contrast agent imaging (USCAI) based on plane waves has recently attracted increasing attention. A series of USCAI techniques have been developed to improve the imaging quality. Most of the existing methods enhance the contrast-to-tissue ratio (CTR) using the time-frequency [...] Read more.
The study of ultrasound contrast agent imaging (USCAI) based on plane waves has recently attracted increasing attention. A series of USCAI techniques have been developed to improve the imaging quality. Most of the existing methods enhance the contrast-to-tissue ratio (CTR) using the time-frequency spectrum differences between the tissue and ultrasound contrast agent (UCA) region. In this paper, a new USCAI method based on bubble region detection was proposed, in which the frequency difference as well as the dissimilarity of tissue and UCA in the spatial domain was taken into account. A bubble wavelet based on the Doinikov model was firstly constructed. Bubble wavelet transformation (BWT) was then applied to strengthen the UCA region and weaken the tissue region. The bubble region was thereafter detected by using the combination of eigenvalue and eigenspace-based coherence factor (ESBCF). The phantom and rabbit in vivo experiment results suggested that our method was capable of suppressing the background interference and strengthening the information of UCA. For the phantom experiment, the imaging CTR was improved by 10.1 dB compared with plane wave imaging based on delay-and-sum (DAS) and by 4.2 dB over imaging based on BWT on average. Furthermore, for the rabbit kidney experiment, the corresponding improvements were 18.0 dB and 3.4 dB, respectively. Full article
(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)
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2613 KiB  
Article
Effect of Ultrafast Imaging on Shear Wave Visualization and Characterization: An Experimental and Computational Study in a Pediatric Ventricular Model
by Annette Caenen, Mathieu Pernot, Ingvild Kinn Ekroll, Darya Shcherbakova, Luc Mertens, Abigail Swillens and Patrick Segers
Appl. Sci. 2017, 7(8), 840; https://doi.org/10.3390/app7080840 - 16 Aug 2017
Cited by 14 | Viewed by 4416
Abstract
Plane wave imaging in Shear Wave Elastography (SWE) captures shear wave propagation in real-time at ultrafast frame rates. To assess the capability of this technique in accurately visualizing the underlying shear wave mechanics, this work presents a multiphysics modeling approach providing access to [...] Read more.
Plane wave imaging in Shear Wave Elastography (SWE) captures shear wave propagation in real-time at ultrafast frame rates. To assess the capability of this technique in accurately visualizing the underlying shear wave mechanics, this work presents a multiphysics modeling approach providing access to the true biomechanical wave propagation behind the virtual image. This methodology was applied to a pediatric ventricular model, a setting shown to induce complex shear wave propagation due to geometry. Phantom experiments are conducted in support of the simulations. The model revealed that plane wave imaging altered the visualization of the shear wave pattern in the time (broadened front and negatively biased velocity estimates) and frequency domain (shifted and/or decreased signal frequency content). Furthermore, coherent plane wave compounding (effective frame rate of 2.3 kHz) altered the visual appearance of shear wave dispersion in both the experiment and model. This mainly affected stiffness characterization based on group speed, whereas phase velocity analysis provided a more accurate and robust stiffness estimate independent of the use of the compounding technique. This paper thus presents a versatile and flexible simulation environment to identify potential pitfalls in accurately capturing shear wave propagation in dispersive settings. Full article
(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)
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2629 KiB  
Article
Automatic Definition of an Anatomic Field of View for Volumetric Cardiac Motion Estimation at High Temporal Resolution
by Alejandra Ortega, João Pedrosa, Brecht Heyde, Ling Tong and Jan D’hooge
Appl. Sci. 2017, 7(7), 752; https://doi.org/10.3390/app7070752 - 24 Jul 2017
Cited by 1 | Viewed by 3911
Abstract
Fast volumetric cardiac imaging requires reducing the number of transmit events within a single volume. One way of achieving this is by limiting the field of view (FOV) of the recording to the myocardium when investigating cardiac mechanics. Although fully automatic solutions towards [...] Read more.
Fast volumetric cardiac imaging requires reducing the number of transmit events within a single volume. One way of achieving this is by limiting the field of view (FOV) of the recording to the myocardium when investigating cardiac mechanics. Although fully automatic solutions towards myocardial segmentation exist, translating that information in a fast ultrasound scan sequence is not trivial. In particular, multi-line transmit (MLT) scan sequences were investigated given their proven capability to increase frame rate (FR) while preserving image quality. The aim of this study was therefore to develop a methodology to automatically identify the anatomically relevant conically shaped FOV, and to translate this to the best associated MLT sequence. This approach was tested on 27 datasets leading to a conical scan with a mean opening angle of 19.7° ± 8.5°, while the mean “thickness” of the cone was 19° ± 3.4°, resulting in a frame rate gain of about 2. Then, to subsequently scan this conical volume, several MLT setups were tested in silico. The method of choice was a 10MLT sequence as it resulted in the highest frame rate gain while maintaining an acceptable cross-talk level. When combining this MLT scan sequence with at least four parallel receive beams, a total frame rate gain with a factor of approximately 80 could be obtained. As such, anatomical scan sequences can increase frame rate significantly while maintaining information of the relevant structures for functional myocardial imaging. Full article
(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)
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Review

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12 pages, 935 KiB  
Review
Riding the Plane Wave: Considerations for In Vivo Study Designs Employing High Frame Rate Ultrasound
by Jason S. Au, Richard L. Hughson and Alfred C. H. Yu
Appl. Sci. 2018, 8(2), 286; https://doi.org/10.3390/app8020286 - 14 Feb 2018
Cited by 7 | Viewed by 5308
Abstract
Advancements in diagnostic ultrasound have allowed for a rapid expansion of the quantity and quality of non-invasive information that clinical researchers can acquire from cardiovascular physiology. The recent emergence of high frame rate ultrasound (HiFRUS) is the next step in the quantification of [...] Read more.
Advancements in diagnostic ultrasound have allowed for a rapid expansion of the quantity and quality of non-invasive information that clinical researchers can acquire from cardiovascular physiology. The recent emergence of high frame rate ultrasound (HiFRUS) is the next step in the quantification of complex blood flow behavior, offering angle-independent, high temporal resolution data in normal physiology and clinical cases. While there are various HiFRUS methods that have been tested and validated in simulations and in complex flow phantoms, there is a need to expand the field into more rigorous in vivo testing for clinical relevance. In this tutorial, we briefly outline the major advances in HiFRUS, and discuss practical considerations of participant preparation, experimental design, and human measurement, while also providing an example of how these frameworks can be immediately applied to in vivo research questions. The considerations put forward in this paper aim to set a realistic framework for research labs which use HiFRUS to commence the collection of human data for basic science, as well as for preliminary clinical research questions. Full article
(This article belongs to the Special Issue Ultrafast Ultrasound Imaging)
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