Determination of the Acoustic Velocity in Tissues Using an Inhomogeneous Media Model

Dameron, David H.

doi:10.1109/t-su.1979.31069

Cited by 4 publications

(2 citation statements)

References 3 publications

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“…They rely on deconvolution methods. 16,17 However, the random nature of biological tissues and the attenuation of the incident pulse with respect to frequency preclude the convolution techniques to be used in real biological tissues. 18 In order to overcome the limitations of the transmission methods and the invasive nature of the reflection methods mentioned previously, and to avoid the complications presented by the deconvolution methods, other approaches have been presented to measure the wave speed.…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic wave speed measurement using the time-delay profile of rf-backscattered signals: Simulation and experimental results

Pereira

Machado

Pereira

2002

The Journal of the Acoustical Society of America

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Conventional methods determine the ultrasonic wave speed measuring the medium path length propagated by a pulsed wave and the corresponding time-of-flight. In this work, the wave speed is determined without the need of the path length. A transmit transducer sends a pulsed wave into the medium (wave speed constant along the beam axis) and the backscattered signal is collected by a hydrophone placed at two distinct positions near the transmitted beam. The time-delay profile, between gated windows of the two rf-signals received by the hydrophone, is determined using a cross-correlation method. Also, a theoretical time-delay profile is determined considering the wave speed as a parameter. The estimated wave speed is obtained upon minimization of the rms error between theoretical and experimental time-delay profiles. A PZT conically focused transmitting transducer with center frequency of 3.3 MHz, focal depth of 30 mm, and beam full width (-3 dB) of 2 mm at the focus was used together with a PZT hydrophone (0.8 mm of aperture). The method was applied to three phantoms (wave speed of 1220, 1540, and 1720 m/s) and, in vitro, to fresh bovine liver sample, immersed in a temperature-controlled water bath. The results present a relative speed error less than 3% when compared with the sound speed obtained by a conventional method.

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Section: Introductionmentioning

confidence: 99%

Ultrasonic wave speed measurement using the time-delay profile of rf-backscattered signals: Simulation and experimental results

Pereira

Machado

Pereira

2002

The Journal of the Acoustical Society of America

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“…Some of the speed estimation methods used deconvolution for solving the inversescattering problem applied to backscattered ultrasound signals [56,57]. Shin et al [58,59] estimated velocities in homogeneous and inhomogeneous media using different point spread functions to perform deconvolution on a known layer boundary position of the images simulated using different sound speeds.…”

Section: Related Workmentioning

confidence: 99%

Stratified-Medium Sound Speed Profiling for CPWC Ultrasound Imaging

D'Souza

Rakhmatov

2020

2020 IEEE International Ultrasonics Symposium (IUS)

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Coherent plane-wave compounding (CPWC) ultrasound is an important modality enabling ultrafast biomedical imaging. To perform CWPC image reconstruction for a stratified (horizontally layered) medium, one needs to know how the speed of sound (SOS) varies with the propagation depth. Incorrect sound speed and layer thickness assumptions can cause focusing errors, degraded spatial resolution and significant geometrical distortions resulting in poor image reconstruction. We aim to determine the speed of sound and thickness values for each horizontal layer to accurately locate the recorded reflection events to their true locations within the medium. Our CPWC image reconstruction process is based on phase-shift migration (PSM) that requires the user to specify the speed of sound and thickness of each layer in advance. Prior to performing phase-shift migration (one layer at a time, starting from the surface), we first estimate the speed of sound values of a given layer using a cosine similarity metric, based on the data obtained by a multi-element transducer array for two different plane-wave emission angles. Then, we use our speed estimate to identify the layer thickness via end-of-layer boundary detection. A low-cost alternative that obtains reconstructed images with fewer phase shifts (i.e., fewer complex multiplications) using a spectral energy threshold is also proposed in this thesis. Our evaluation results, based on the CPWC imaging simulation of a three-layer medium, show that our sound speed and layer thickness estimates are within 4% of their true values (i.e., those used to generate simulated data). We have also confirmed the accuracy of our speed and layer thickness estimation separately, using two experimental datasets representing two special cases. For speed estimation, we used iv a CPWC imaging dataset for a constant-speed (i.e., single-layer) medium, yielding estimates within 1% of their true values. For layer thickness estimation, we used a monostatic (i.e., single-element) synthetic-aperture (SA) imaging dataset of the threelayer medium, also yielding estimates within 1% of their true values. Our evaluation results for the low-cost alternative showed a 93% reduction in complex multiplications for the three-layer CPWC imaging dataset and 76% for the three-layer monostatic SA imaging dataset, producing images nearly similar to those obtained using the original PSM methods.

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Ultrasound propagation in anisotropic soft tissues: The application of linear elastic theory

Levinson

1987

Journal of Biomechanics

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Determination of the Acoustic Velocity in Tissues Using an Inhomogeneous Media Model

Cited by 4 publications

References 3 publications

Ultrasonic wave speed measurement using the time-delay profile of rf-backscattered signals: Simulation and experimental results

Ultrasonic wave speed measurement using the time-delay profile of rf-backscattered signals: Simulation and experimental results

Stratified-Medium Sound Speed Profiling for CPWC Ultrasound Imaging

Ultrasound propagation in anisotropic soft tissues: The application of linear elastic theory

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