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

Pereira, Fernando Reiszel; Machado, João Carlos; Pereira, Wagner Coelho de Albuquerque

doi:10.1121/1.1445787

Cited by 18 publications

(16 citation statements)

References 35 publications

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“…Similar artifacts, with a stair-stepped appearance of time-delay profile, has been reported Robinson et al [23]. Simulation results given by Pereira et al [24] also confirm time-delay profiles positively biased with respect to theoretical ones.…”

Section: Discussionsupporting

confidence: 73%

Ultrasound characterization of coronary artery wall in vitro using temperature-dependent wave speed

Pereira

Machado

Foster

2003

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

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Temperature dependence of the speed of sound, @c=@T , is examined as a parameter to characterize tissue-equivalent phantoms and coronary artery tissue in vitro. The experimental system comprises an ultrasound biomicroscope, operating at center frequency of 50 MHz, and a temperature controlled micropositioning sample cell. Radio frequency (RF) backscattered signals were recorded, with a digital oscilloscope, from 64 independent positions and at 5 temperatures starting at 31 C (phantom) and 36 C (tissue) in steps of one degree. Time shift per degree Celsius ( t= T ) was obtained with a correlation technique applied between gated sections of two RF-signals collected with one degree temperature difference from the same location in the sample. The average h t= Ti, calculated for every position of the gated sections along the propagation axis of the ultrasound beam, has the slope proportional to the difference between the linear coefficient of thermal expansion and the thermal sensitivity of the speed of sound. Calibration measurements of @ c = @ T , made with single-and three-layer tissue equivalent phantoms, correlated well (r 0:91) with those measured by the time-offlight substitution method. The @ c = @ Twas estimated for the three layers on the wall of eight samples of human coronary arteries, obtained at autopsy from four individuals.The @c=@T for the intima layers decreases as the disease progresses from mild intimal thickening to a more advanced atherosclerosis.

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Section: Discussionsupporting

confidence: 73%

Ultrasound characterization of coronary artery wall in vitro using temperature-dependent wave speed

Pereira

Machado

Foster

2003

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

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“…Several correctors have been proposed to adjust the speed of sound in ultrasound imaging [50][51][52]. As a side note, because it is a constant speed method, the Stolt's f-k migration would be also limited in transcranial ultrasound imaging since the sound propagates much faster in the skull bone than in the brain.…”

Section: Pwi Using F-k Migration: Limitations and Perspectivesmentioning

confidence: 99%

Stolt's f-k migration for plane wave ultrasound imaging

Garcia¹,

Tarnec²,

Muth³

et al. 2013

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

217

165

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Ultrafast ultrasound is an emerging modality that offers new perspectives and opportunities in medical imaging. Plane wave imaging (PWI) allows one to attain very high frame rates by transmission of planar ultrasound wavefronts. As a plane wave reaches a given scatterer, the latter becomes a secondary source emitting upward spherical waves and creating a diffraction hyperbola in the received RF (radio-frequency) signals. To produce an image of the scatterers, all the hyperbolas must be migrated back to their apexes. In order to perform beamforming of plane wave echo RFs and return high-quality images at high frame rates, we propose a new migration method carried out in the frequency-wavenumber (f-k) domain.The f-k migration for PWI has been adapted from the Stolt migration for seismic imaging. This migration technique is based on the exploding reflector model (ERM), which consists in assuming that all the scatterers explode in concert and become acoustic sources. The classical ERM model, however, is not appropriate for PWI. We showed that the ERM can be made suitable for PWI by a spatial transformation of the hyperbolic traces present in the RF data. In vitro experiments were performed to sketch the advantages of PWI with Stolt's f-k migration over the conventional delayand-sum (DAS) approach. The Stolt's f-k migration was also compared with the Fourier-based method developed by J-Y Lu.Our findings show that multi-angle compounded f-k migrated images are of quality similar to those obtained with a state-of-the-art dynamic focusing mode. This remained true even with a very small number of steering angles thus ensuring a highly competitive frame rate. In addition, the new FFT-based f-k migration provides comparable or better contrast-to-noise ratio and lateral resolution than the Lu's and DAS migration schemes. Matlab codes of the Stolt's f-k migration for PWI are provided.

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“…As the PSF is assumed symmetric, only its amplitude spectrum is estimated and removed in the de-convolution scheme. Therefore, in order to obtain more accurate PSF with assuming that the PSF might be symmetric or asymmetric, we set the cepstrum for negative time to any value like below (7). The computation of the complex cepstrum is greatly simplified like the assumption of minimum phase.…”

Section: Log| ( )| = Log| ( )| + Log| ( )| (3)mentioning

confidence: 99%

Parametric phase information based 2D Cepstrum PSF estimation method for blind de-convolution of ultrasound imaging

et al. 2014

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In the ultrasound imaging system, blurring which occurs after passing through ultrasound scanner system, represents point spread function (PSF) that describes the response of the ultrasound imaging system to a point source distribution. So, de-blurring can be achieved by de-convolving the ultrasound images with an estimated of corresponding PSF. However, it is hard to attain an accurate estimation of PSF due to the unknown properties of the tissues of the human body through the ultrasound signal propagates. In this paper, we present a new method for PSF estimation in the Fourier domain (FD) based on parametric minimum phase information, and simultaneously, it performs fast 2D de-convolution in the ultrasound imaging system. Although most of complex cepstrum methods [14], are obtained using complex 2D phase unwrapping [18] [19] in order to estimate the FD-phase information of PSF, our algorithm estimates the 2D PSF using 2D FD-phase information with the parametric weighting factor α and β. They affect the feature of PSF shapes. This makes the computations much simpler and the estimation more accurate. Our algorithm works on the beam-formed uncompressed radio-frequency data, with pre-measured and estimated 2D PSFs database from actual probe used. We have tested our algorithm with vera-sonic system and commercial ultrasound scanner (Philips C4-2), in known speed of sound phantoms and unknown speeds in vivo scans.

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

Cited by 18 publications

References 35 publications

Ultrasound characterization of coronary artery wall in vitro using temperature-dependent wave speed

Ultrasound characterization of coronary artery wall in vitro using temperature-dependent wave speed

Stolt's f-k migration for plane wave ultrasound imaging

Parametric phase information based 2D Cepstrum PSF estimation method for blind de-convolution of ultrasound imaging

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