Accuracy of backscatter coefficient estimation in aberrating media using different phase aberration correction strategies - A simulation study

González, Eduardo; Sheth, Niral; Castaneda, Benjamín; Dahl, Jeremy J.; Lavarello, Roberto

doi:10.1109/ultsym.2014.0608

Cited by 5 publications

(2 citation statements)

References 14 publications

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“…Approaches for aberration corrections include using the peak position of cross correlation with iteration methods to estimate the arrival time differences across the transducer array [74,75]. Multiple estimates of the aberration delays for a group of adjacent elements were computed in the multi-lag cross correlation method and the arrival time was estimated using least-meansquare error [76][77][78]. In order to obtain a more accurate aberration measurement profile, a 2-D spatial filter was designed to be implemented prior to the measurement to suppress off-axis signals [57].…”

Section: Phase Aberration Correctionmentioning

confidence: 99%

Novel ultrasound transmission and reconstruction techniques for synthetic transmit aperture imaging

Gong¹

2021

Preprint

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This dissertation describes ultrasound algorithms developed for synthetic transmit aperture (STA) imaging during the transmission and the image reconstruction stages. Images generated using these algorithms demonstrate image quality enhancement both theoretically and experimentally. The advanced algorithms also improve the application of STA imaging. Due to the single element transmission pattern, the low signal-to-noise ratio is a major limitation for STA imaging. A delay-encoded transmission scheme (DE-STA) was designed in this dissertation to encode all the transmissions. The decoded RF signals were equivalent to the standard STA signals, but with a higher SNR. Improved image qualities were observed under DE-STA transmission in terms of lateral resolution (+28%), peak-signal-to-noise ratio (PSNR, +7 dB) and target contrast-to-noise ratio (CNR, +360%) compared to those acquired with the standard STA mode. The stability of DE-STA was analyzed and verified under various noise levels by the special distribution of the singular values of the encoding matrix through singular value decomposition (SVD) (i.e. all the singular values were the same except for the first one and the last one). A more efficient decoding process was also derived based on pseudo-inversion (PI) and the computation complexity was reduced by 2/3. Speckle and undesired sidelobe signals can reduce the lesion CNR and detectability in ultrasound images. Typically, the CNR can be increased by spatial compounding (SC) or frequency compounding (FC) during reconstruction. We proposed methods to implement a 2-dimentional (2-D) aperture domain filter in the SC/FC processes, referred to as filtered spatial compounding (FSC) and filtered frequency compounding (FFC), for synthetic transmit aperture (STA) imaging. Both techniques reduced the sidelobe interference and provided improved lesion CNR. Consequently, the lesion signal-to-noise ratio (lSNR) in FSC and FFC increased (up to +130%), compared to that in the standard delay-and-sum (DAS) method. This dissertation investigates all these proposed advanced ultrasound algorithms, with the end goal of implementing these methods in STA imaging to extend its application in clinic.

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Section: Phase Aberration Correctionmentioning

confidence: 99%

Novel ultrasound transmission and reconstruction techniques for synthetic transmit aperture imaging

Gong¹

2021

Preprint

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“…The first two were used because they are common methods used in the PAC literature. 13,17,18 The SCM was selected because it is based on the covariance matrix and it could possibly integrate better with the MV beamforming calculations.…”

Section: Pacmentioning

confidence: 99%

Effects of Phase Aberration and Phase Aberration Correction on the Minimum Variance Beamformer

2017

Self Cite

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The minimum variance (MV) beamformer has the potential to enhance the resolution and contrast of ultrasound images but is sensitive to steering vector errors. Robust MV beamformers have been proposed but mainly evaluated in the presence of gross sound speed mismatches, and the impact of phase aberration correction (PAC) methods in mitigating the effects of phase aberration in MV beamformed images has not been explored. In this study, an analysis of the effects of aberration on conventional MV and eigenspace MV (ESMV) beamformers is carried out. In addition, the impact of three PAC algorithms on the performance of MV beamforming is analyzed. The different beamformers were tested on simulated data and on experimental data corrupted with electronic and tissue-based aberration. It is shown that all gains in performance of the MV beamformer with respect to delay-and-sum (DAS) are lost at high aberration strengths. For instance, with an electronic aberration of 60 ns, the lateral resolution of DAS degrades by 17% while MV degrades by 73% with respect to the images with no aberration. Moreover, although ESMV shows robustness at low aberration levels, its degradation at higher aberrations is approximately the same as that of regular MV. It is also shown that basic PAC methods improve the aberrated MV beamformer. For example, in the case of electronic aberration, multi-lag reduces degradation in lateral resolution from 73% to 28% and contrast loss from 85% to 25%. These enhancements allow the combination of MV and PAC to outperform DAS and PAC and ESMV in moderate and strong aberrations. We conclude that the effect of aberration on the MV beamformer is stronger than previously reported in the literature and that PAC is needed to improve its clinical potential.

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Effects of phase aberration correction methods on the minimum variance beamformer

Chau

Dahl

Lavarello

2016

2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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The minimum variance (MV) beamformer is a method that has the potential to enhance the resolution and contrast of ultrasound images. However, it suffers from sensitivity to speed of sound errors and aberration. Although there have been several studies on the application of phase aberration correction (PAC) methods to conventional delay-and-sum (DAS) beamforming, the benefits of PAC methods in mitigating the effects of phase aberration in MV beamformed images are not well understood. A study of this type would be helpful in designing a robust beamformer based on PAC knowledge present in the literature. This study analyzes three PAC algorithms (multi-lag cross-correlation, Rigby's beamsum and scaled covariance matrix) and their impact on the performance of the MV beamformer in the presence of second order phase aberrations. The PAC methods in combination with the MV beamformer were tested on simulated and experimental data corrupted with an electronically created near field phase aberrator. It is shown that all gains in performance of the MV beamformer with respect to DAS is lost at high aberration strengths. For instance, at 60 ns of aberration the lateral resolution of DAS degrades by 22% while MV degrades by 600%. It is also shown that basic PAC methods improve the aberrated MV beamformer. PAC methods reduces degradation in lateral resolution from 600% to 5%. Similar improvements are observed in peak sidelobe level (96% to 27%), contrast (88% to 49% for the simulations and 43% to 15% for experiments) and contrast-to-noise ratio (86% to 42% for the simulations and 68% to 55% for experiments). These enhancements allow the MV beamformer to outperform DAS even in the strongest aberration case.

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Accuracy of backscatter coefficient estimation in aberrating media using different phase aberration correction strategies - A simulation study

Cited by 5 publications

References 14 publications

Novel ultrasound transmission and reconstruction techniques for synthetic transmit aperture imaging

Novel ultrasound transmission and reconstruction techniques for synthetic transmit aperture imaging

Effects of Phase Aberration and Phase Aberration Correction on the Minimum Variance Beamformer

Effects of phase aberration correction methods on the minimum variance beamformer

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