Temporal approach of the synthetic aperture imaging using Hadamard matrix

Mosca, Frédéric; Nicolas, Jean‐Marie; Kopp, L.; Couade, Mathieu

doi:10.1121/1.2932899

Cited by 2 publications

(2 citation statements)

References 3 publications

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“…without losing the maximum amplitude level for each transmission). Hadamard matrices have many applications in signal processing, coding or cryptography (Horadam 2007) and have already been applied to synthetic aperture imaging in Ultrasound (Chiao et al 1997, Mosca et al 2008. An Hadamard matrix is a square matrix with +1 or −1 coefficients and whose rows are mutually orthogonal.…”

Section: Multiplane Wave Imaging Basic Principlesmentioning

confidence: 99%

Multiplane wave imaging increases signal-to-noise ratio in ultrafast ultrasound imaging

et al. 2015

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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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Section: Multiplane Wave Imaging Basic Principlesmentioning

confidence: 99%

Multiplane wave imaging increases signal-to-noise ratio in ultrafast ultrasound imaging

et al. 2015

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“…As a consequence, their focusing is not as ideal as STA. To obtain the complete STA dataset with higher SNR, spatial coding methods such as Hadamard encoding (Mosca et al 2008, Chiao et al 1997, 2000, S-sequence (Harrison et al 2014), and delay-encoded transmission (Gong et al 2015, Gong et al 2016 were proposed. In these methods, all the elements are encoded and activated in each transmission.…”

Section: Introductionmentioning

confidence: 99%

Partial Hadamard encoded synthetic transmit aperture for high frame rate imaging with minimal l ₂-norm least squares method

Zhang¹,

Liu²,

Fan³

et al. 2022

Phys. Med. Biol.

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Objective: Synthetic transmit aperture (STA) ultrasound imaging is well known for ideal focusing in the full field of view. However, it suffers from low signal-to-noise ratio (SNR) and low frame rate, because each transducer element must be activated individually. In our previous study, we encoded all the transducer elements with partial Hadamard matrix and reconstructed the complete STA dataset with compressed sensing (CS) algorithm (CS-STA). As all the elements are activated in each transmission and the number of transmissions is smaller than that of STA, this method can achieve higher SNR and higher frame rate. Its main drawback is the time-consuming CS reconstruction (~ hours). In this study, we propose to accelerate the complete STA dataset reconstruction with minimal l2-norm least squares method. Approach: Partial Hadamard apodized PW transmissions were performed to acquire the PW dataset. Thereafter, the complete STA dataset can be reconstructed from the PW dataset with minimal l2-norm least squares method. Due to the orthogonality of partial Hadamard matrix, the minimal l2-norm least squares solution can be easily calculated. Main results: The proposed method is tested with simulation data and experimental phantom and in-vivo data. The results demonstrate that the proposed method achieves ~5×103 times faster reconstruction speed than CS algorithm. The simulation results demonstrate that the proposed method is capable of achieving the same accuracy as the conventional CS-STA method for the STA dataset reconstruction. The simulations, phantom and in-vivo experiments show that the proposed method is capable of improving the generalized contrast-to-noise ratio (gCNR) and SNR with maintained spatial resolution and fewer transmissions, compared with STA. Significance: In conclusion, the improved image quality and reduced computational time of LS-STA pave the way for its real-time applications in the clinics.

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Temporal approach of the synthetic aperture imaging using Hadamard matrix

Cited by 2 publications

References 3 publications

Multiplane wave imaging increases signal-to-noise ratio in ultrafast ultrasound imaging

Multiplane wave imaging increases signal-to-noise ratio in ultrafast ultrasound imaging

Partial Hadamard encoded synthetic transmit aperture for high frame rate imaging with minimal l ₂-norm least squares method

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Temporal approach of the synthetic aperture imaging using Hadamard matrix

Cited by 2 publications

References 3 publications

Multiplane wave imaging increases signal-to-noise ratio in ultrafast ultrasound imaging

Multiplane wave imaging increases signal-to-noise ratio in ultrafast ultrasound imaging

Partial Hadamard encoded synthetic transmit aperture for high frame rate imaging with minimal l 2-norm least squares method

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Partial Hadamard encoded synthetic transmit aperture for high frame rate imaging with minimal l ₂-norm least squares method