Phase-aberration correction using signals from point reflectors and diffuse scatterers: basic principles

Flax, S.W.; O'Donnell, M.

doi:10.1109/58.9333

Cited by 460 publications

(224 citation statements)

References 8 publications

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“…The interference between these rays causes strong amplitude distortions in breast UT. Different deaberration methods have been proposed to compensate for phase distortion in UT [18], [19]. However, so far they have been inadequate to correct the strong amplitude distortion caused by refraction [20].…”

Section: Introductionmentioning

confidence: 99%

Effects of acoustic heterogeneity in breast thermoacoustic tomography

Wang

2003

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

119

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Abstract-The effects of wavefront distortions induced by acoustic heterogeneities in breast thermoacoustic tomography (TAT) are studied. Amplitude distortions are shown to be insignificant for different scales of acoustic heterogeneities. For wavelength-scale, or smaller, heterogeneities, amplitude distortion of the wavefront is minor as a result of diffraction when the detectors are placed in the far field of the heterogeneities. For larger-scale heterogeneities at the parenchyma wall, by using a ray approach (geometric optics), we show that no refraction-induced multipath interference occurs and, consequently, that no severe amplitude distortion, such as is found in ultrasound tomography, exists. Next, we consider the effects of phase distortions (errors in time-of-flight) in our numerical studies. The numerical results on the spreads of point sources and boundaries caused by the phase distortions are in good agreement with the proposed formula. After that, we demonstrate that the blurring of images can be compensated for by using the distribution of acoustic velocity in the tissues in the reconstructions. The effects of the errors in the acoustical velocities on this compensation also are investigated. An approach to implement the compensation using only TAT data is proposed. Lastly, the differences in the effects of acoustic heterogeneity and the generation of speckles in breast TAT and breast ultrasound imaging are discussed.

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Section: Introductionmentioning

confidence: 99%

Effects of acoustic heterogeneity in breast thermoacoustic tomography

Wang

2003

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

119

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“…Several different point-target based algorithms have been proposed (Flax and O'Donnell, 1988;Zhao and Trahey, 1991;Fink, 1992). All point-target techniques rely on the existence of sparsely distributed point scatterers/point sources in the region of interest.…”

Section: Introduction and Literaturementioning

confidence: 99%

Towards Aberration Correction of Transcranial Ultrasound Using Acoustic Droplet Vaporization

Haworth

Fowlkes

Carson

et al. 2008

Ultrasound in Medicine & Biology

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We report on the first experiments demonstrating the transcranial acoustic formation of stable gas bubbles that can be used for transcranial ultrasound aberration correction. It is demonstrated that the gas bubbles can be formed transcranially by phase-transitioning single, superheated, micron-size, liquid dodecafluoropentane droplets with ultrasound, a process known as acoustic droplet vaporization (ADV). ADV was performed at 550 kHz, where the skull is less attenuating and aberrating, allowing for higher-amplitudes to be reached at the focus. Additionally, it is demonstrated that time-reversal focusing at 1 MHz can be used to correct for transcranial aberrations with a single gas bubble acting as a point beacon. Aberration correction was performed using a synthetic aperture approach and verified by the realignment of the scattered waveforms. Under the conditions described below, time-reversal aberration correction using gas bubbles resulted in a gain of 1.9 ± 0.3 in an introduced focusing factor. This is a small fraction of the gain anticipated from complete transmitreceive of a fully-populated two-dimensional array with sub-wavelength elements.

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“…From this approach, we found that the status of each quality factor is not identical. Actually, the texture contrast has little preference for the group decision-making because of its higher sensitive to the sound speed errors which can be seen in [9]. So, not all the rules need to be used in actual processing, e.g.…”

Section: Discussionmentioning

confidence: 99%

“…Meanwhile, isolated point reflectors couldn't be present in clinical ultrasound imaging [9]. Therefore, to deal with complex clinical cases, this paper presents a sound speed optimization system based on fuzzy sets with image texture as quality factors.…”

Section: Introductionmentioning

confidence: 99%

Sound speed optimization based on fuzzy sets using image texture as quality factors

2017

BIO Web Conf.

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Abstract.A constant sound speed of 1540 m/s is usually used by ultrasound imaging systems for calculating delay curves in beamforming. A mismatch of this constant system sound speed and the real one in human tissue could result in significant defocusing and degrade the image resolution in the modern ultrasound imaging system. This paper has investigated characteristics and potential relationship of image texture parameters to image focusing quality due to unmatched speed of sound. Algorithms for sound speed optimization (SSO) system based on fuzzy process and image texture parameters are presented. The proposed method has been investigated and verified from phantom imaging including speckle, point targets and cyst images. Test results show that individual texture feature may help to determine appropriate sound speed used for beamforming; however, only the proposed fuzzy process based system can achieve the best sound speed detection with consistent and robust output.

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Phase-aberration correction using signals from point reflectors and diffuse scatterers: basic principles

Cited by 460 publications

References 8 publications

Effects of acoustic heterogeneity in breast thermoacoustic tomography

Effects of acoustic heterogeneity in breast thermoacoustic tomography

Towards Aberration Correction of Transcranial Ultrasound Using Acoustic Droplet Vaporization

Sound speed optimization based on fuzzy sets using image texture as quality factors

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