The Experts below are selected from a list of 9972 Experts worldwide ranked by ideXlab platform
Mickael Tanter - One of the best experts on this subject based on the ideXlab platform.
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a large aperture row column addressed probe for in vivo 4d Ultrafast doppler ultrasound Imaging
Physics in Medicine and Biology, 2018Co-Authors: Jack Sauvage, Mickael Tanter, Mathieu Pernot, Martin Flesch, Guillaume Ferin, An Nguyendinh, Jonathan Poree, Thomas DeffieuxAbstract:: Four-dimensional (4D) Ultrafast ultrasound Imaging was recently proposed to image and quantify blood flow with high sensitivity in 3D as well as anatomical, mechanical or functional information. In 4D Ultrafast Imaging, coherent compounding of tilted planes waves emitted by a 2D matrix array were used to image the medium at high volume rate. 4D Ultrafast Imaging, however, requires a high channel count (>1000) to drive those probes. Alternative approaches have been proposed and investigated to efficiently reduce the density of elements, such as sparse or under-sampled arrays while maintaining a decent image quality and high volume rate. The row-columns configuration presents the advantage of keeping a large active surface with a low amount of elements and a simple geometry. In this study, we investigate the row and column addressed (RCA) approach with the orthogonal plane wave (OPW) compounding strategy using real hardware limitations. We designed and built a large 7 MHz 128 + 128 probe dedicated to vascular Imaging and connected to a 256-channel scanner to implement the OPW Imaging scheme. Using this strategy, we demonstrate that 4D Ultrafast Power Doppler Imaging of a large volume of [Formula: see text] up to [Formula: see text] depth, both in vitro on flow phantoms and in vivo on the carotid artery of a healthy volunteer at a volume rate of 834 Hz.
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adaptive spatiotemporal svd clutter filtering for Ultrafast doppler Imaging using similarity of spatial singular vectors
IEEE Transactions on Medical Imaging, 2018Co-Authors: Jerome Baranger, Mickael Tanter, Bastien Arnal, Fabienne Perren, Olivier Baud, Charlie DemeneAbstract:Singular value decomposition of Ultrafast Imaging ultrasonic data sets has recently been shown to build a vector basis far more adapted to the discrimination of tissue and blood flow than the classical Fourier basis, improving by large factor clutter filtering and blood flow estimation. However, the question of optimally estimating the boundary between the tissue subspace and the blood flow subspace remained unanswered. Here, we introduce an efficient estimator for automatic thresholding of subspaces and compare it to an exhaustive list of thirteen estimators that could achieve this task based on the main characteristics of the singular components, namely the singular values, the temporal singular vectors, and the spatial singular vectors. The performance of those fourteen estimators was tested in vitro in a large set of controlled experimental conditions with different tissue motion and flow speeds on a phantom. The estimator based on the degree of resemblance of spatial singular vectors outperformed all others. Apart from solving the thresholding problem, the additional benefit with this estimator was its denoising capabilities, strongly increasing the contrast to noise ratio and lowering the noise floor by at least 5 dB. This confirms that, contrary to conventional clutter filtering techniques that are almost exclusively based on temporal characteristics, efficient clutter filtering of Ultrafast Doppler Imaging cannot overlook space. Finally, this estimator was applied in vivo on various organs (human brain, kidney, carotid, and thyroid) and showed efficient clutter filtering and noise suppression, improving largely the dynamic range of the obtained Ultrafast power Doppler images.
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non invasive evaluation of aortic stiffness dependence with aortic blood pressure and internal radius by shear wave elastography and Ultrafast Imaging
Irbm, 2017Co-Authors: Clement Papadacci, Mickael Tanter, Emmanuel Messas, T Mirault, Blandine Dizier, Mathieu PernotAbstract:Abstract Background Elastic properties of arteries have long been recognized as playing a major role in the cardiovascular system. However, non-invasive in vivo assessment of local arterial stiffness remains challenging and imprecise as current techniques rely on indirect estimates such as wall deformation or pulse wave velocity. Recently, Shear Wave Elastography (SWE) has been proposed to non-invasively assess the intrinsic arterial stiffness. Methods In this study, we applied SWE in the abdominal aortas of rats while increasing blood pressure (BP) to investigate the dependence of shear wave speed with invasive arterial pressure and non-invasive arterial diameter measurements. A 15 MHz linear array connected to an Ultrafast ultrasonic scanner, set non-invasively, on the abdominal aorta of anesthetized rats ( N = 5 ) was used. The SWE acquisition followed by an Ultrafast (UF) acquisition was repeated at different moment of the cardiac cycle to assess shear wave speed and arterial diameter variations respectively. Invasive arterial BP catheter placed in the carotid, allowed the accurate measurement of pressure responses to increasing does of phenylephrine infused via a venous catheter. Results The SWE acquisition coupled to the UF acquisition was repeated for different range of pressure. For normal range of BP, the shear wave speed was found to follow the aortic BP variation during a cardiac cycle. A minimum of (5.06 ± 0.82) m/s during diastole and a maximum of (5.97 ± 0.90) m/s during systole was measured. After injection of phenylephrine, a strong increase of shear wave speed (13.85 ± 5.51) m/s was observed for a peak systolic arterial pressure of (190 ± 10) mmHg. A non-linear relationship between shear wave speed and arterial BP was found. A complete non-invasive method was proposed to characterize the artery with shear wave speed combined with arterial diameter variations. Finally, the results were validated against two elastic moduli: the incremental elastic modulus and the pressure elastic modulus derived from BP and arterial diameter variations. Conclusion The slopes derived from the proposed method could be a useful index to characterize arteries completely non-invasively in the clinic without the need to use blood pressure measurements.
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high frequency row column addressed matrix array for volumetric Ultrafast ultrasound Imaging
Internaltional Ultrasonics Symposium, 2017Co-Authors: Guillaume Ferin, Mickael Tanter, Thomas Deffieux, Martin Flesch, Claire Bantignies, Mariecoline Dumoux, Tony Mateo, Agnes Lejeune, Bogdan Rosinski, Mathieu PernotAbstract:Volumetric “Ultrafast” Imaging is one of the major trends in ultrasound Imaging techniques. It indeed paves the way for novel modalities when combined with Doppler, elastography and contrast Imaging [1]. Unfortunately, due to the complexity and the inherently unaffordable costs, fully populated matrix-based systems are facing to pricing problems that limit their commercial development. Recently, row-column addressed (RCA) matrix transducer approaches have been proposed to overcome both complexity and costs issues but in a limited frequency range, i.e. below 10MHz. However, there is also a tremendous need to deploy this solution to higher frequencies, typically 15MHz and above, mainly for brain functional ultrasound Imaging investigation.
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Ultrafast harmonic coherent compound uhcc Imaging for high frame rate echocardiography and shear wave elastography
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2016Co-Authors: Mafalda Correia, Mickael Tanter, Jean Provost, Simon Chatelin, Olivier Villemain, Mathieu PernotAbstract:Transthoracic shear-wave elastography (SWE) of the myocardium remains very challenging due to the poor quality of transthoracic Ultrafast Imaging and the presence of clutter noise, jitter, phase aberration, and ultrasound reverberation. Several approaches, such as diverging-wave coherent compounding or focused harmonic Imaging, have been proposed to improve the Imaging quality. In this study, we introduce Ultrafast harmonic coherent compounding (UHCC), in which pulse-inverted diverging waves are emitted and coherently compounded, and show that such an approach can be used to enhance both SWE and high frame rate (FR) B-mode Imaging. UHCC SWE was first tested in phantoms containing an aberrating layer and was compared against pulse-inversion harmonic Imaging and against Ultrafast coherent compounding (UCC) Imaging at the fundamental frequency. In vivo feasibility of the technique was then evaluated in six healthy volunteers by measuring myocardial stiffness during diastole in transthoracic Imaging. We also demonstrated that improvements in Imaging quality could be achieved using UHCC B-mode Imaging in healthy volunteers. The quality of transthoracic images of the heart was found to be improved with the number of pulse-inverted diverging waves with a reduction of the Imaging mean clutter level up to 13.8 dB when compared against UCC at the fundamental frequency. These results demonstrated that UHCC B-mode Imaging is promising for Imaging deep tissues exposed to aberration sources with a high FR.
Mathias Fink - One of the best experts on this subject based on the ideXlab platform.
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high contrast Ultrafast Imaging of the heart
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2014Co-Authors: Clement Papadacci, Mathieu Couade, Mathias Fink, Mathieu Pernot, Mickael TanterAbstract:Noninvasive Ultrafast Imaging of intrinsic waves such as electromechanical waves or remotely induced shear waves in elastography Imaging techniques for human cardiac applications remains challenging. In this paper, we propose Ultrafast Imaging of the heart with adapted sector size by coherently compounding diverging waves emitted from a standard transthoracic cardiac phased-array probe. As in Ultrafast Imaging with plane wave coherent compounding, diverging waves can be summed coherently to obtain high-quality images of the entire heart at high frame rate in a full field of view. To image the propagation of shear waves with a large SNR, the field of view can be adapted by changing the angular aperture of the transmitted wave. Backscattered echoes from successive circular wave acquisitions are coherently summed at every location in the image to improve the image quality while maintaining very high frame rates. The transmitted diverging waves, angular apertures, and subaperture sizes were tested in simulation, and Ultrafast coherent compounding was implemented in a commercial scanner. The improvement of the Imaging quality was quantified in phantoms and in one human heart, in vivo. Imaging shear wave propagation at 2500 frames/s using 5 diverging waves provided a large increase of the SNR of the tissue velocity estimates while maintaining a high frame rate. Finally, Ultrafast Imaging with 1 to 5 diverging waves was used to image the human heart at a frame rate of 4500 to 900 frames/s over an entire cardiac cycle. Spatial coherent compounding provided a strong improvement of the Imaging quality, even with a small number of transmitted diverging waves and a high frame rate, which allows Imaging of the propagation of electromechanical and shear waves with good image quality.
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Ultrafast Imaging in biomedical ultrasound
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2014Co-Authors: Mickael Tanter, Mathias FinkAbstract:Although the use of ultrasonic plane-wave transmissions rather than line-per-line focused beam transmissions has been long studied in research, clinical application of this technology was only recently made possible through developments in graphical processing unit (GPU)-based platforms. Far beyond a technological breakthrough, the use of plane or diverging wave transmissions enables attainment of Ultrafast frame rates (typically faster than 1000 frames per second) over a large field of view. This concept has also inspired the emergence of completely novel Imaging modes which are valuable for ultrasound-based screening, diagnosis, and therapeutic monitoring. In this review article, we present the basic principles and implementation of Ultrafast Imaging. In particular, present and future applications of Ultrafast Imaging in biomedical ultrasound are illustrated and discussed.
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quantitative assessment of arterial wall biomechanical properties using shear wave Imaging
Ultrasound in Medicine and Biology, 2010Co-Authors: Mathieu Couade, Mathias Fink, Mathieu Pernot, Claire Prada, Emmanuel Messas, Joseph Emmerich, Patrick Bruneval, Aline Laure Criton, Mickael TanterAbstract:A new ultrasound-based technique is proposed to assess the arterial stiffness: the radiation force of an ultrasonic beam focused on the arterial wall induces a transient shear wave (� 10 ms) whose propagation is tracked by Ultrafast Imaging. The large and high-frequency content (100 to 1500 Hz) of the induced wave enables studying the wave dispersion, which is shown experimentally in vitro and numerically to be linked to arterial wall stiffness and geometry.The proposedmethod isappliedinvivo.Byrepeatingtheacquisition upto 10timesper second(theo- retical maximal frame rate is � 100 Hz), it is possible to assess in vivo the arterial wall elasticity dynamics: shear modulus of a healthy volunteer carotid wall is shown to vary strongly during the cardiac cycle and measured to be 130 ± 15 kPa in systole and 80 ± 10 kPa in diastole. (E-mail: mathieu.couade@gmail.com) 2010 World Feder- ation for Ultrasound in Medicine & Biology.
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Ultrafast Imaging of ultrasound contrast agents
Ultrasound in Medicine and Biology, 2009Co-Authors: Olivier Couture, Mickael Tanter, Mathias Fink, Souad Bannouf, Gabriel Montaldo, Jeanfrancois AubryAbstract:The disappearance of ultrasound contrast agents after disruption can provide useful information on their environment. However, in vivo acoustical Imaging of this transient phenomenon, which has a duration on the order of milliseconds, requires high frame rates that are unattainable by conventional ultrasound scanners. In this article, Ultrafast Imaging is applied to microbubble tracking using a 128-element linear array and an elastography scanner. Contrast agents flowing in a wall-less tissue phantom are insonified with a high-intensity disruption pulse followed by a series of plane waves emitted at a 5kHz PRF. A collection of compounded images depicting the evolution of microbubbles is obtained after the echoes are beamformed in silico. The backscattering of the microbubbles appears to increase in the first image after disruption (4 ms) and decrease following an exponential decay in the next hundred milliseconds. This microbubble dynamic depends on the length and amplitude of the high-intensity pulse. Furthermore, confined microbubbles are found to differ significantly from their free-flowing counterparts in their dissolution curves. The high temporal resolution provided by Ultrafast Imaging could help distinguish targeted microbubbles during molecular Imaging.
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quantitative assessment of breast lesion viscoelasticity initial clinical results using supersonic shear Imaging
Ultrasound in Medicine and Biology, 2008Co-Authors: Mickael Tanter, Jeremy Bercoff, A Athanasiou, Thomas Deffieux, Jeanluc Gennisson, G Montaldo, Marie Muller, A Tardivon, Mathias FinkAbstract:Abtract This paper presents an initial clinical evaluation of in vivo elastography for breast lesion Imaging using the concept of supersonic shear Imaging. This technique is based on the combination of a radiation force induced in tissue by an ultrasonic beam and an Ultrafast Imaging sequence capable of catching in real time the propagation of the resulting shear waves. The local shear wave velocity is recovered using a time-offlight technique and enables the 2-D mapping of shear elasticity. This Imaging modality is implemented on a conventional linear probe driven by a dedicated Ultrafast echographic device. Consequently, it can be performed during a standard echographic examination. The clinical investigation was performed on 15 patients, which corresponded to 15 lesions (4 cases BI-RADS 3, 7 cases BI-RADS 4 and 4 cases BI-RADS 5). The ability of the supersonic shear Imaging technique to provide a quantitative and local estimation of the shear modulus of abnormalities with a millimetric resolution is illustrated on several malignant (invasive ductal and lobular carcinoma) and benign cases (fibrocystic changes and viscous cysts). In the investigated cases, malignant lesions were found to be significantly different from benign solid lesions with respect to their elasticity values. Cystic lesions have shown no shear wave propagate at all in the lesion (because shear waves do not propage in liquid). These preliminary clinical results directly demonstrate the clinical feasibility of this new elastography technique in providing quantitative assessment of relative stiffness of breast tissues. This technique of evaluating tissue elasticity gives valuable information that is complementary to the B-mode morphologic information. More extensive studies are necessary to validate the assumption that this new mode potentially helps the physician in both false-positive and false-negative rejection. (E-mail: Mickael.tanter@espci.fr )
Thomas Deffieux - One of the best experts on this subject based on the ideXlab platform.
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a large aperture row column addressed probe for in vivo 4d Ultrafast doppler ultrasound Imaging
Physics in Medicine and Biology, 2018Co-Authors: Jack Sauvage, Mickael Tanter, Mathieu Pernot, Martin Flesch, Guillaume Ferin, An Nguyendinh, Jonathan Poree, Thomas DeffieuxAbstract:: Four-dimensional (4D) Ultrafast ultrasound Imaging was recently proposed to image and quantify blood flow with high sensitivity in 3D as well as anatomical, mechanical or functional information. In 4D Ultrafast Imaging, coherent compounding of tilted planes waves emitted by a 2D matrix array were used to image the medium at high volume rate. 4D Ultrafast Imaging, however, requires a high channel count (>1000) to drive those probes. Alternative approaches have been proposed and investigated to efficiently reduce the density of elements, such as sparse or under-sampled arrays while maintaining a decent image quality and high volume rate. The row-columns configuration presents the advantage of keeping a large active surface with a low amount of elements and a simple geometry. In this study, we investigate the row and column addressed (RCA) approach with the orthogonal plane wave (OPW) compounding strategy using real hardware limitations. We designed and built a large 7 MHz 128 + 128 probe dedicated to vascular Imaging and connected to a 256-channel scanner to implement the OPW Imaging scheme. Using this strategy, we demonstrate that 4D Ultrafast Power Doppler Imaging of a large volume of [Formula: see text] up to [Formula: see text] depth, both in vitro on flow phantoms and in vivo on the carotid artery of a healthy volunteer at a volume rate of 834 Hz.
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high frequency row column addressed matrix array for volumetric Ultrafast ultrasound Imaging
Internaltional Ultrasonics Symposium, 2017Co-Authors: Guillaume Ferin, Mickael Tanter, Thomas Deffieux, Martin Flesch, Claire Bantignies, Mariecoline Dumoux, Tony Mateo, Agnes Lejeune, Bogdan Rosinski, Mathieu PernotAbstract:Volumetric “Ultrafast” Imaging is one of the major trends in ultrasound Imaging techniques. It indeed paves the way for novel modalities when combined with Doppler, elastography and contrast Imaging [1]. Unfortunately, due to the complexity and the inherently unaffordable costs, fully populated matrix-based systems are facing to pricing problems that limit their commercial development. Recently, row-column addressed (RCA) matrix transducer approaches have been proposed to overcome both complexity and costs issues but in a limited frequency range, i.e. below 10MHz. However, there is also a tremendous need to deploy this solution to higher frequencies, typically 15MHz and above, mainly for brain functional ultrasound Imaging investigation.
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Multiplane wave Imaging increases signal-to-noise ratio in Ultrafast ultrasound Imaging
Physics in Medicine and Biology, 2015Co-Authors: Elodie Tiran, Thomas Deffieux, Mathieu Pernot, Mafalda Correia, David Maresca, Bruno-felix Osmanski, Lim-anna Sieu, Antoine Bergel, Ivan Cohen, Mickael TanterAbstract:Ultrafast Imaging using plane or diverging waves has recently enabled new ultrasound Imaging modes with improved sensitivity and very high frame rates. Some of these new Imaging modalities include shear wave elastography, Ultrafast Doppler, Ultrafast contrast-enhanced Imaging and functional ultrasound Imaging. Even though Ultrafast Imaging already encounters clinical success, increasing even more its penetration depth and signal-to-noise ratio for dedicated applications would be valuable. Ultrafast Imaging relies on the coherent compounding of backscattered echoes resulting from successive tilted plane waves emissions; this produces high-resolution ultrasound images with a trade-off between final frame rate, contrast and resolution. In this work, we introduce multiplane wave Imaging, a new method that strongly improves Ultrafast images signal-to-noise ratio by virtually increasing the emission signal amplitude without compromising the frame rate. This method relies on the successive transmissions of multiple plane waves with differently coded amplitudes and emission angles in a single transmit event. Data from each single plane wave of increased amplitude can then be obtained, by recombining the received data of successive events with the proper coefficients. The benefits of multiplane wave for B-mode, shear wave elastography and Ultrafast Doppler Imaging are experimentally demonstrated. Multiplane wave with 4 plane waves emissions yields a 5.8 +/- 0.5 dB increase in signal-to-noise ratio and approximately 10 mm in penetration in a calibrated ultrasound phantom (0.7 d MHz(-1) cm(-1)). In shear wave elastography, the same multiplane wave configuration yields a 2.07 +/- 0.05 fold reduction of the particle velocity standard deviation and a two-fold reduction of the shear wave velocity maps standard deviation. In functional ultrasound Imaging, the mapping of cerebral blood volume results in a 3 to 6 dB increase of the contrast-to-noise ratio in deep structures of the rodent brain.
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4 d Ultrafast shear wave Imaging
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2015Co-Authors: Jeanluc Gennisson, Thomas Deffieux, Mathieu Pernot, Clement Papadacci, Jean Provost, Marion Imbault, Mickael TanterAbstract:Over the last ten years, shear wave elastography (SWE) has seen considerable development and is now routinely used in clinics to provide mechanical characterization of tissues to improve diagnosis. The most advanced technique relies on the use of an Ultrafast scanner to generate and image shear waves in real time in a 2-D plane at several thousands of frames per second. We have recently introduced 3-D Ultrafast ultrasound Imaging to acquire with matrix probes the 3-D propagation of shear waves generated by a dedicated radiation pressure transducer in a single acquisition. In this study, we demonstrate 3-D SWE based on Ultrafast volumetric Imaging in a clinically applicable configuration. A 32 × 32 matrix phased array driven by a customized, programmable, 1024-channel ultrasound system was designed to perform 4-D shear-wave Imaging. A matrix phased array was used to generate and control in 3-D the shear waves inside the medium using the acoustic radiation force. The same matrix array was used with 3-D coherent plane wave compounding to perform high-quality Ultrafast Imaging of the shear wave propagation. Volumetric Ultrafast acquisitions were then beamformed in 3-D using a delay-and-sum algorithm. 3-D volumetric maps of the shear modulus were reconstructed using a time-of-flight algorithm based on local multiscale cross-correlation of shear wave profiles in the three main directions using directional filters. Results are first presented in an isotropic homogeneous and elastic breast phantom. Then, a full 3-D stiffness reconstruction of the breast was performed in vivo on healthy volunteers. This new full 3-D Ultrafast ultrasound system paves the way toward real-time 3-D SWE.
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quantitative assessment of breast lesion viscoelasticity initial clinical results using supersonic shear Imaging
Ultrasound in Medicine and Biology, 2008Co-Authors: Mickael Tanter, Jeremy Bercoff, A Athanasiou, Thomas Deffieux, Jeanluc Gennisson, G Montaldo, Marie Muller, A Tardivon, Mathias FinkAbstract:Abtract This paper presents an initial clinical evaluation of in vivo elastography for breast lesion Imaging using the concept of supersonic shear Imaging. This technique is based on the combination of a radiation force induced in tissue by an ultrasonic beam and an Ultrafast Imaging sequence capable of catching in real time the propagation of the resulting shear waves. The local shear wave velocity is recovered using a time-offlight technique and enables the 2-D mapping of shear elasticity. This Imaging modality is implemented on a conventional linear probe driven by a dedicated Ultrafast echographic device. Consequently, it can be performed during a standard echographic examination. The clinical investigation was performed on 15 patients, which corresponded to 15 lesions (4 cases BI-RADS 3, 7 cases BI-RADS 4 and 4 cases BI-RADS 5). The ability of the supersonic shear Imaging technique to provide a quantitative and local estimation of the shear modulus of abnormalities with a millimetric resolution is illustrated on several malignant (invasive ductal and lobular carcinoma) and benign cases (fibrocystic changes and viscous cysts). In the investigated cases, malignant lesions were found to be significantly different from benign solid lesions with respect to their elasticity values. Cystic lesions have shown no shear wave propagate at all in the lesion (because shear waves do not propage in liquid). These preliminary clinical results directly demonstrate the clinical feasibility of this new elastography technique in providing quantitative assessment of relative stiffness of breast tissues. This technique of evaluating tissue elasticity gives valuable information that is complementary to the B-mode morphologic information. More extensive studies are necessary to validate the assumption that this new mode potentially helps the physician in both false-positive and false-negative rejection. (E-mail: Mickael.tanter@espci.fr )
Shigao Chen - One of the best experts on this subject based on the ideXlab platform.
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improved super resolution ultrasound microvessel Imaging with spatiotemporal nonlocal means filtering and bipartite graph based microbubble tracking
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2018Co-Authors: Pengfei Song, Joshua D Trzasko, Armando Manduca, Runqing Huang, Ramanathan Kadirvel, David F Kallmes, Shigao ChenAbstract:Super-resolution ultrasound microvessel Imaging with contrast microbubbles has recently been proposed by multiple studies, demonstrating outstanding resolution with high potential for clinical applications. This paper aims at addressing the potential noise issue in in vivo human super-resolution Imaging with Ultrafast plane-wave Imaging. The rich spatiotemporal information provided by Ultrafast Imaging presents features that allow microbubble signals to be separated from background noise. In addition, the high-frame-rate recording of microbubble data enables the implementation of robust tracking algorithms commonly used in particle tracking velocimetry. In this paper, we applied the nonlocal means (NLM) denoising filter on the spatiotemporal domain of the microbubble data to preserve the microbubble tracks caused by microbubble movement and suppress random background noise. We then implemented a bipartite graph-based pairing method with the use of persistence control to further improve the microbubble signal quality and microbubble tracking fidelity. In an in vivo rabbit kidney perfusion study, the NLM filter showed effective noise rejection and substantially improved microbubble localization. The bipartite graph pairing and persistence control demonstrated further noise reduction, improved microvessel delineation, and a more consistent microvessel blood flow speed measurement. With the proposed methods and freehand scanning on a free-breathing rabbit, a single microvessel cross-sectional profile with full-width at half-maximum of $57~\mu \text{m}$ could be imaged at approximately 2-cm depth (ultrasound transmit center frequency = 8 MHz, theoretical spatial resolution $\sim 200~\mu \text{m}$ ). Cortical microvessels that are $76~\mu \text{m}$ apart can also be clearly separated. These results suggest that the proposed methods have good potential in facilitating robust in vivo clinical super-resolution microvessel Imaging.
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delay encoded harmonic Imaging de hi in multiplane wave compounding
Internaltional Ultrasonics Symposium, 2017Co-Authors: Ping Gong, Pengfei Song, Shigao ChenAbstract:The development of Ultrafast ultrasound Imaging brings great opportunities to improve Imaging technologies such as shear wave elastography and Ultrafast Doppler Imaging. In Ultrafast Imaging, there are trade-offs among image signal-to-noise ratio (SNR), resolution, and the high frame rate. Multiplane wave (MW) Imaging is proposed to solve this tradeoff by encoding multiple plane waves with positive/negative pulse polarities during one transmission event (i.e., pulse-echo event), to improve SNR in Ultrafast Imaging. However, it suffers from stronger reverberation clutters in B-mode images compared to standard plane wave compounding due to longer transmitted pulses. In this paper, we propose a delay-encoded harmonic Imaging (DE-HI) technique to implement HI in MW compounding. It encodes the 2nd harmonic signals with 1/4 period delay calculated at the transmit center frequency during MW transmissions, rather than reversing the pulse polarity. This is because the 2nd harmonic signals cannot be encoded by pulse inversion. Received DE-HI signals can then be decoded in the frequency domain to recover the signals as in single plane wave emissions, but mainly with increased SNR at the 2nd harmonic component instead of the fundamental component. DE-HI reduces image clutters as in HI and improves image SNR as in MW. The image quality enhancement was demonstrated by an in-vivo human liver study, in which DE-HI provided enhanced contrast-to-noise ratio (CNR) and vessel identification, as compared to plane wave fundamental Imaging, MW compounding, and plane wave HI without coding. The enhanced Imaging quality and potential high frame rate of DE-HI made the method promising for a wide spectrum of Imaging applications.
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delay encoded harmonic Imaging de hi in multiplane wave compounding
IEEE Transactions on Medical Imaging, 2017Co-Authors: Ping Gong, Pengfei Song, Shigao ChenAbstract:The development of Ultrafast ultrasound Imaging brings great opportunities to improve Imaging technologies such as shear wave elastography and Ultrafast Doppler Imaging. In Ultrafast Imaging, several tilted plane or diverging wave images are coherently combined to form a compounded image, leading to trade-offs among image signal-to-noise ratio (SNR), resolution, and post-compounded frame rate. Multiplane wave (MW) Imaging is proposed to solve this trade-off by encoding multiple plane waves with Hadamard matrix during one transmission event (i.e. pulse-echo event), to improve image SNR without sacrificing the resolution or frame rate. However, it suffers from stronger reverberation artifacts in B-mode images compared to standard plane wave compounding due to longer transmitted pulses. If harmonic Imaging can be combined with MW Imaging, the reverberation artifacts and other clutter noises such as sidelobes and multipath scattering clutters should be suppressed. The challenge, however, is that the Hadamard codes used in MW Imaging cannot encode the $2^{\mathrm {nd}}$ harmonic component by inversing the pulse polarity. In this paper, we propose a delay-encoded harmonic Imaging (DE-HI) technique to encode the $2^{\mathrm {nd}}$ harmonic with a one quarter period delay calculated at the transmit center frequency, rather than reversing the pulse polarity during multiplane wave emissions. Received DE-HI signals can then be decoded in the frequency domain to recover the signals as in single plane wave emissions, but mainly with improved SNR at the $2^{\mathrm {nd}}$ harmonic component instead of the fundamental component. DE-HI was tested experimentally with a point target, a B-mode Imaging phantom, and in-vivo human liver Imaging. Improvements in image contrast-to-noise ratio (CNR), spatial resolution, and lesion-signal-to-noise ratio ( $l$ SNR) have been achieved compared to standard plane wave compounding, MW Imaging, and standard harmonic Imaging (maximal improvement of 116% on CNR and 115% on $l$ SNR as compared to standard HI around 55 mm depth in the B-mode Imaging phantom study). The potential high frame rate and the stability of encoding and decoding processes of DE-HI were also demonstrated, which made DE-HI promising for a wide spectrum of Imaging applications.
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Ultrafast synthetic transmit aperture Imaging using hadamard encoded virtual sources with overlapping sub apertures
IEEE Transactions on Medical Imaging, 2017Co-Authors: Ping Gong, Pengfei Song, Shigao ChenAbstract:The development of Ultrafast ultrasound Imaging offers great opportunities to improve Imaging technologies, such as shear wave elastography and Ultrafast Doppler Imaging. In Ultrafast Imaging, there are tradeoffs among image signal-to-noise ratio (SNR), resolution, and post-compounded frame rate. Various approaches have been proposed to solve this tradeoff, such as multiplane wave Imaging or the attempts of implementing synthetic transmit aperture Imaging. In this paper, we propose an Ultrafast synthetic transmit aperture (USTA) Imaging technique using Hadamard-encoded virtual sources with overlapping sub-apertures to enhance both image SNR and resolution without sacrificing frame rate. This method includes three steps: 1) create virtual sources using sub-apertures; 2) encode virtual sources using Hadamard matrix; and 3) add short time intervals (a few microseconds) between transmissions of different virtual sources to allow overlapping sub-apertures. The USTA was tested experimentally with a point target, a B-mode phantom, and in vivo human kidney micro-vessel Imaging. Compared with standard coherent diverging wave compounding with the same frame rate, improvements on image SNR, lateral resolution (+33%, with B-mode phantom Imaging), and contrast ratio (+3.8 dB, with in vivo human kidney micro-vessel Imaging) have been achieved. The ${f}$ -number of virtual sources, the number of virtual sources used, and the number of elements used in each sub-aperture can be flexibly adjusted to enhance resolution and SNR. This allows very flexible optimization of USTA for different applications.
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accelerated singular value based ultrasound blood flow clutter filtering with randomized singular value decomposition and randomized spatial downsampling
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2017Co-Authors: Pengfei Song, Joshua D Trzasko, Armando Manduca, Ramanathan Kadirvel, David F Kallmes, Bo Qiang, Shigao ChenAbstract:Singular value decomposition (SVD)-based ultrasound blood flow clutter filters have recently demonstrated substantial improvement in clutter rejection for Ultrafast plane wave microvessel Imaging, and have become the commonly used clutter filtering method for many novel Ultrafast Imaging applications such as functional ultrasound and super-resolution Imaging. At present, however, the computational burden of SVD remains as a major hurdle for practical implementation and clinical translation of this method. To address this challenge, in the study we present two blood flow clutter filtering methods based on randomized SVD (rSVD) and randomized spatial downsampling to accelerate SVD clutter filtering with minimal compromise to the clutter filter performance. rSVD accelerates SVD computation by approximating the $k$ largest singular values, while random downsampling accelerates both full SVD and rSVD by decomposing the original large data matrix into small matrices that can be processed in parallel. An in vitro blood flow phantom study with the presence of heavy tissue clutter showed significantly improved computational performance using the proposed methods with minimal deterioration to the clutter filter performance (less than 3-dB reduction in blood to clutter ratio, less than 0.2-cm2/s2 increase in flow mean squared error, less than 0.1-cm/s increase in the standard deviation of the vessel blood flow signal, and less than 0.3-cm/s increase in tissue clutter velocity for both full SVD and rSVD when the downsampling factor was less than $20\times$ ). The maximum acceleration was about threefold from randomized spatial downsampling, and approximately another threefold from rSVD. An in vivo rabbit kidney perfusion study showed that rSVD provided comparable performance to full SVD in clutter rejection in vivo (maximum difference of blood to clutter ratio was less than 0.6 dB), and random downsampling provided artifact-free perfusion Imaging results when combined with both full SVD and rSVD. The blood to clutter ratio was still above 10 dB with a downsampling factor of $60\times$ . We also demonstrated real-time microvessel Imaging feasibility (~40-ms processing time) by combining rSVD with random downsampling. The findings and methods presented in this paper may greatly facilitate the new area of Ultrafast microvessel Imaging research.
Mathieu Pernot - One of the best experts on this subject based on the ideXlab platform.
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a large aperture row column addressed probe for in vivo 4d Ultrafast doppler ultrasound Imaging
Physics in Medicine and Biology, 2018Co-Authors: Jack Sauvage, Mickael Tanter, Mathieu Pernot, Martin Flesch, Guillaume Ferin, An Nguyendinh, Jonathan Poree, Thomas DeffieuxAbstract:: Four-dimensional (4D) Ultrafast ultrasound Imaging was recently proposed to image and quantify blood flow with high sensitivity in 3D as well as anatomical, mechanical or functional information. In 4D Ultrafast Imaging, coherent compounding of tilted planes waves emitted by a 2D matrix array were used to image the medium at high volume rate. 4D Ultrafast Imaging, however, requires a high channel count (>1000) to drive those probes. Alternative approaches have been proposed and investigated to efficiently reduce the density of elements, such as sparse or under-sampled arrays while maintaining a decent image quality and high volume rate. The row-columns configuration presents the advantage of keeping a large active surface with a low amount of elements and a simple geometry. In this study, we investigate the row and column addressed (RCA) approach with the orthogonal plane wave (OPW) compounding strategy using real hardware limitations. We designed and built a large 7 MHz 128 + 128 probe dedicated to vascular Imaging and connected to a 256-channel scanner to implement the OPW Imaging scheme. Using this strategy, we demonstrate that 4D Ultrafast Power Doppler Imaging of a large volume of [Formula: see text] up to [Formula: see text] depth, both in vitro on flow phantoms and in vivo on the carotid artery of a healthy volunteer at a volume rate of 834 Hz.
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non invasive evaluation of aortic stiffness dependence with aortic blood pressure and internal radius by shear wave elastography and Ultrafast Imaging
Irbm, 2017Co-Authors: Clement Papadacci, Mickael Tanter, Emmanuel Messas, T Mirault, Blandine Dizier, Mathieu PernotAbstract:Abstract Background Elastic properties of arteries have long been recognized as playing a major role in the cardiovascular system. However, non-invasive in vivo assessment of local arterial stiffness remains challenging and imprecise as current techniques rely on indirect estimates such as wall deformation or pulse wave velocity. Recently, Shear Wave Elastography (SWE) has been proposed to non-invasively assess the intrinsic arterial stiffness. Methods In this study, we applied SWE in the abdominal aortas of rats while increasing blood pressure (BP) to investigate the dependence of shear wave speed with invasive arterial pressure and non-invasive arterial diameter measurements. A 15 MHz linear array connected to an Ultrafast ultrasonic scanner, set non-invasively, on the abdominal aorta of anesthetized rats ( N = 5 ) was used. The SWE acquisition followed by an Ultrafast (UF) acquisition was repeated at different moment of the cardiac cycle to assess shear wave speed and arterial diameter variations respectively. Invasive arterial BP catheter placed in the carotid, allowed the accurate measurement of pressure responses to increasing does of phenylephrine infused via a venous catheter. Results The SWE acquisition coupled to the UF acquisition was repeated for different range of pressure. For normal range of BP, the shear wave speed was found to follow the aortic BP variation during a cardiac cycle. A minimum of (5.06 ± 0.82) m/s during diastole and a maximum of (5.97 ± 0.90) m/s during systole was measured. After injection of phenylephrine, a strong increase of shear wave speed (13.85 ± 5.51) m/s was observed for a peak systolic arterial pressure of (190 ± 10) mmHg. A non-linear relationship between shear wave speed and arterial BP was found. A complete non-invasive method was proposed to characterize the artery with shear wave speed combined with arterial diameter variations. Finally, the results were validated against two elastic moduli: the incremental elastic modulus and the pressure elastic modulus derived from BP and arterial diameter variations. Conclusion The slopes derived from the proposed method could be a useful index to characterize arteries completely non-invasively in the clinic without the need to use blood pressure measurements.
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high frequency row column addressed matrix array for volumetric Ultrafast ultrasound Imaging
Internaltional Ultrasonics Symposium, 2017Co-Authors: Guillaume Ferin, Mickael Tanter, Thomas Deffieux, Martin Flesch, Claire Bantignies, Mariecoline Dumoux, Tony Mateo, Agnes Lejeune, Bogdan Rosinski, Mathieu PernotAbstract:Volumetric “Ultrafast” Imaging is one of the major trends in ultrasound Imaging techniques. It indeed paves the way for novel modalities when combined with Doppler, elastography and contrast Imaging [1]. Unfortunately, due to the complexity and the inherently unaffordable costs, fully populated matrix-based systems are facing to pricing problems that limit their commercial development. Recently, row-column addressed (RCA) matrix transducer approaches have been proposed to overcome both complexity and costs issues but in a limited frequency range, i.e. below 10MHz. However, there is also a tremendous need to deploy this solution to higher frequencies, typically 15MHz and above, mainly for brain functional ultrasound Imaging investigation.
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Ultrafast harmonic coherent compound uhcc Imaging for high frame rate echocardiography and shear wave elastography
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2016Co-Authors: Mafalda Correia, Mickael Tanter, Jean Provost, Simon Chatelin, Olivier Villemain, Mathieu PernotAbstract:Transthoracic shear-wave elastography (SWE) of the myocardium remains very challenging due to the poor quality of transthoracic Ultrafast Imaging and the presence of clutter noise, jitter, phase aberration, and ultrasound reverberation. Several approaches, such as diverging-wave coherent compounding or focused harmonic Imaging, have been proposed to improve the Imaging quality. In this study, we introduce Ultrafast harmonic coherent compounding (UHCC), in which pulse-inverted diverging waves are emitted and coherently compounded, and show that such an approach can be used to enhance both SWE and high frame rate (FR) B-mode Imaging. UHCC SWE was first tested in phantoms containing an aberrating layer and was compared against pulse-inversion harmonic Imaging and against Ultrafast coherent compounding (UCC) Imaging at the fundamental frequency. In vivo feasibility of the technique was then evaluated in six healthy volunteers by measuring myocardial stiffness during diastole in transthoracic Imaging. We also demonstrated that improvements in Imaging quality could be achieved using UHCC B-mode Imaging in healthy volunteers. The quality of transthoracic images of the heart was found to be improved with the number of pulse-inverted diverging waves with a reduction of the Imaging mean clutter level up to 13.8 dB when compared against UCC at the fundamental frequency. These results demonstrated that UHCC B-mode Imaging is promising for Imaging deep tissues exposed to aberration sources with a high FR.
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Multiplane wave Imaging increases signal-to-noise ratio in Ultrafast ultrasound Imaging
Physics in Medicine and Biology, 2015Co-Authors: Elodie Tiran, Thomas Deffieux, Mathieu Pernot, Mafalda Correia, David Maresca, Bruno-felix Osmanski, Lim-anna Sieu, Antoine Bergel, Ivan Cohen, Mickael TanterAbstract:Ultrafast Imaging using plane or diverging waves has recently enabled new ultrasound Imaging modes with improved sensitivity and very high frame rates. Some of these new Imaging modalities include shear wave elastography, Ultrafast Doppler, Ultrafast contrast-enhanced Imaging and functional ultrasound Imaging. Even though Ultrafast Imaging already encounters clinical success, increasing even more its penetration depth and signal-to-noise ratio for dedicated applications would be valuable. Ultrafast Imaging relies on the coherent compounding of backscattered echoes resulting from successive tilted plane waves emissions; this produces high-resolution ultrasound images with a trade-off between final frame rate, contrast and resolution. In this work, we introduce multiplane wave Imaging, a new method that strongly improves Ultrafast images signal-to-noise ratio by virtually increasing the emission signal amplitude without compromising the frame rate. This method relies on the successive transmissions of multiple plane waves with differently coded amplitudes and emission angles in a single transmit event. Data from each single plane wave of increased amplitude can then be obtained, by recombining the received data of successive events with the proper coefficients. The benefits of multiplane wave for B-mode, shear wave elastography and Ultrafast Doppler Imaging are experimentally demonstrated. Multiplane wave with 4 plane waves emissions yields a 5.8 +/- 0.5 dB increase in signal-to-noise ratio and approximately 10 mm in penetration in a calibrated ultrasound phantom (0.7 d MHz(-1) cm(-1)). In shear wave elastography, the same multiplane wave configuration yields a 2.07 +/- 0.05 fold reduction of the particle velocity standard deviation and a two-fold reduction of the shear wave velocity maps standard deviation. In functional ultrasound Imaging, the mapping of cerebral blood volume results in a 3 to 6 dB increase of the contrast-to-noise ratio in deep structures of the rodent brain.
