Improved in vivo abdominal image quality using real-time estimation and correction of wavefront arrival time errors

Rigby, K.W.; Chalek, C.L.; Haider, B.; Lewandowski, R.S.; O’Donnell, Matthew; Smith, L.S.; Wildes, Douglas

doi:10.1109/ultsym.2000.921639

Cited by 29 publications

(38 citation statements)

References 30 publications

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“…It then follows, based on the random walk arguments presented in [2], that the average speckle brightness also has sinusoidal dependence. Furthermore, the form of (1) suggests that MBA is functionally similar to the "correlation against the beam-sum" method [5]. Figure 2 plots an experimentally measured brightness curve.…”

Section: Introductionmentioning

confidence: 98%

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P3G-3 The "N-Shot" Maximum Brightness Algorithm: An Efficient and Robust Delay-Aberration Estimator

Robinson

Haun

2006

2006 IEEE Ultrasonics Symposium

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The iterative "maximum brightness" delay aberration correction algorithm searches on each array element for the beamformer delay that maximizes the spatial-average speckle brightness. The array elements are optimized in turn until the entire aperture is corrected. A minimum of two transmits per line in the ROI (two "shots") are required for each element but the actual number is typically much greater, especially when small delay steps are employed. Furthermore, thermal or motioninduced noise can introduce false, transient maxima. These often cause the iterative search to halt prematurely at incorrect delay values, a problem which is also exacerbated as the step size is reduced. This paper describes a new family of algorithms, termed "N-shot", in which the number of shots is constant and small (as low as N = 2). All are based on the empirical observation that the average speckle brightness exhibits a nearly sinusoidal variation with respect to any one element's beamformer delay. Application of a priori knowledge allows the phase of the sinusoid, and hence the delay aberration value for a given element, to be determined with only two shots. An additional shot allows brightness trends due to "motion noise" to be estimated and removed. Appropriate separation of the delays used for the shots reduces susceptibility to thermal noise. Compared to the iterative algorithm, this new approach is at least as fast and typically much faster, the number of transmits is deterministic and independent of delay quantization, and it has reduced susceptibility to thermal and motion noise. The effectiveness of the algorithm was tested experimentally using an artificial aberrator attached to a phased array. Comparisons between aberrated and corrected phantom images confirm the ability of the N-shot algorithm to determine delay aberrations with only two ROI firings for each array element.

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Section: Introductionmentioning

confidence: 98%

“…Like correlation-based methods [3]- [5], MBA assumes that the aberrations are usefully approximated by a near-field phase screen. MBA then derives the set of beamformer delays that maximizes the spatial average speckle brightness within a region of interest (ROI).…”

Section: Introductionmentioning

confidence: 99%

P3G-3 The "N-Shot" Maximum Brightness Algorithm: An Efficient and Robust Delay-Aberration Estimator

Robinson

Haun

2006

2006 IEEE Ultrasonics Symposium

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“…Introduction R ecently, researchers have applied adaptive imaging techniques, including phase-aberration correction, to 1.5D and 1.75D arrays, typically 3 × 80 to 6 × 96 elements [1]- [5]. These multirow arrays allow focusing in both azimuth and elevation dimensions and enable better estimation of aberration profiles.…”

mentioning

confidence: 99%

“…Although most 1-D transducers meet this criteria in the lateral dimension, they fall far from it in the elevation dimension. Even with 1.75D arrays, there is limited sampling in the elevation dimension, with typical elevation dimensions of 1 mm [7] to 2.5 mm [5]. Research has suggested that an elevation pitch at least 75%, but perhaps as fine as 25 to 30% of the aberration correlation length, might be needed for effective aberration measurements [2], [8].…”

mentioning

confidence: 99%

Phase-aberration correction with a 3-D ultrasound scanner: feasibility study

Ivancevich

Dahl

Trahey

et al. 2006

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…Phase correction with this mode, however, requires twice the amount of time for correction than the SRA mode. In addition to multi-lag cross-correlation, a multi-lag speckle brightness [9] and the beamsum algorithm [10] were available for estimation of the delay profile.…”

Section: A Real-time Adaptive Imagingmentioning

confidence: 99%

Phase correction of skull aberration with 1.75-D and 2-D arrays using speckle targets

Dahl¹,

Ivancevich²,

Keen³

et al.

IEEE Ultrasonics Symposium, 2005.

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Wavefront distortion induced by the skull severely impacts transcranial ultrasound. In particular, the skull reduces the ability to monitor flow in the cerebral vasculature. We present B-scan and color flow images, aberratred with polymer casts of skull bone, that have been improved with near-field phase correction techniques. These algorithms rely on speckle targets for estimation of the phase profile.Real-time adaptive imaging experiements in tissue-mimicking phantoms with 4 mm spherical voids were performed using multi-lag cross-correlation and multi-lag speckle brightness phase correction algorithms. The real-time adaptive imaging was constructed on a Siemens Antares TM scanner and used a custom 3.5 MHz, 1.75-D transducer (8 × 96 elements). Phase correction with the 1.75-D array was performed in a matter of a few seconds. The contrast-to-speckle (CSR) of the spherical voids improved from 1.16 ± 0.39 in the aberrated images to 1.52 ± 0.37 in the phase corrected images.Using a 2.5 MHz, 2-D array on a real time 3-D scanner similar experiments with spherical voids were performed. The CSR of the lesions on the 3-D scanner improved from 0.9 in the aberrated images to 1.6 in the phase corrected images. In addition, phase correction was shown to improve the estimation of 3-D color flow when the transducer was focused on a speckle target through the skull cast.

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Improved in vivo abdominal image quality using real-time estimation and correction of wavefront arrival time errors

Cited by 29 publications

References 30 publications

P3G-3 The "N-Shot" Maximum Brightness Algorithm: An Efficient and Robust Delay-Aberration Estimator

P3G-3 The "N-Shot" Maximum Brightness Algorithm: An Efficient and Robust Delay-Aberration Estimator

Phase-aberration correction with a 3-D ultrasound scanner: feasibility study

Phase correction of skull aberration with 1.75-D and 2-D arrays using speckle targets

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