Spectral Shifts of Ultrasonic Propagation through Media with Nonlinear Dispersive Attenuation

Ophir, Jonathan; Jaeger, Paul

doi:10.1177/016173468200400304

Cited by 33 publications

(4 citation statements)

References 3 publications

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“…At all speed-of-sound values, both axial and lateral FWHMs increase as the depth increases. This is mainly due to the TMM's nonlinear acoustic attenuation frequency spectrum, 61,62 which causes a decrease in the spectral bandwidth as shown in Fig. 7(c) and a reduction of central frequency as shown in Fig.…”

Section: Effects Of Reconstruction Speed Of Sound Onmentioning

confidence: 99%

Two-layer heterogeneous breast phantom for photoacoustic imaging

et al. 2017

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Photoacoustic tomography (PAT) is emerging as a potentially important aid for breast cancer detection. Well-validated tissue-simulating phantoms are needed for objective, quantitative, and physically realistic testing for system development. Prior reported PAT phantoms with homogenous structures do not incorporate the irregular layered structure of breast tissue. To assess the impact of this simplification, we design and construct two-layer breast phantoms incorporating vessel-simulating inclusions and realistic undulations at the fat/fibroglandular tissue interface. The phantoms are composed of custom poly(vinyl chloride) plastisol formulations mimicking the acoustic properties of two breast tissue types and tissue-relevant similar optical properties. Resulting PAT images demonstrate that in tissue with acoustic heterogeneity, lateral size of imaging targets is sensitive to the choice of sound speed in image reconstruction. The undulating boundary can further degrade a target's lateral size due to sound speed variation in tissue and refraction of sound waves at the interface. The extent of this degradation is also influenced by the geometric relationship between an absorber and the boundary. Results indicate that homogeneous phantom matrixes may underestimate the degradation of PAT image quality in breast tissue, whereas heterogeneous phantoms can provide more realistic testing through improved reproduction of spatial variations in physical properties.

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Section: Effects Of Reconstruction Speed Of Sound Onmentioning

confidence: 99%

Two-layer heterogeneous breast phantom for photoacoustic imaging

et al. 2017

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“…The experimental spectral shifts in frequency of the fast and slow waves were compared to the spectral shifts predicted by the theory of Ophir and Jaeger (1982). When a wideband ultrasonic pulse propagates through a lossy medium whose attenuation coefficient increases with frequency, the higher frequency components will be attenuated more than lower frequency components.…”

Section: F Estimation Of Apparent Frequencymentioning

confidence: 99%

“…where f 0 is the center frequency of the reference signal, f c is the downshifted center frequency, b k is the slope of the attenuation coefficient (nBUA), d is the propagation distance, and r 2 is the variance of the spectrum of the transmitted pulse (Ophir and Jaeger, 1982). The predicted spectral shifts for the fast and slow waves were determined using Eq.…”

Section: F Estimation Of Apparent Frequencymentioning

confidence: 99%

Conventional, Bayesian, and Modified Prony's methods for characterizing fast and slow waves in equine cancellous bone

Groopman

Katz

Holland

et al. 2015

The Journal of the Acoustical Society of America

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Conventional, Bayesian, and the modified least-squares Prony's plus curve-fitting (MLSP þ CF) methods were applied to data acquired using 1 MHz center frequency, broadband transducers on a single equine cancellous bone specimen that was systematically shortened from 11.8 mm down to 0.5 mm for a total of 24 sample thicknesses. Due to overlapping fast and slow waves, conventional analysis methods were restricted to data from sample thicknesses ranging from 11.8 mm to 6.0 mm. In contrast, Bayesian and MLSP þ CF methods successfully separated fast and slow waves and provided reliable estimates of the ultrasonic properties of fast and slow waves for sample thicknesses ranging from 11.8 mm down to 3.5 mm. Comparisons of the three methods were carried out for phase velocity at the center frequency and the slope of the attenuation coefficient for the fast and slow waves. Good agreement among the three methods was also observed for average signal loss at the center frequency. The Bayesian and MLSP þ CF approaches were able to separate the fast and slow waves and provide good estimates of the fast and slow wave properties even when the two wave modes overlapped in both time and frequency domains making conventional analysis methods unreliable.

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“…From ( 5) and ( 7), attenuation has a low-pass effect, causing a downshift of the center frequency of the echoes as the propagation distance increases [16,17,41] and limiting the resolution. Such effect is represented in Figure 3a which shows a typical radiation transfer function |H r (f, z)| as a function of both frequency f and propagation distance z.…”

Section: A Model For a Single Targetmentioning

confidence: 99%

A linear model approach for ultrasonic inverse problems with attenuation and dispersion

Carcreff

Bourguignon²,

Idier³

et al. 2014

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

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Ultrasonic inverse problems such as spike train deconvolution, synthetic aperture focusing, or tomography attempt to reconstruct spatial properties of an object (discontinuities, delaminations, flaws, etc.) from noisy and incomplete measurements. They require an accurate description of the data acquisition process. Dealing with frequency-dependent attenuation and dispersion is therefore crucial because both phenomena modify the wave shape as the travel distance increases. In an inversion context, this paper proposes to exploit a linear model of ultrasonic data taking into account attenuation and dispersion. The propagation distance is discretized to build a finite set of radiation impulse responses. Attenuation is modeled with a frequency power law and then dispersion is computed to yield physically consistent responses. Using experimental data acquired from attenuative materials, this model outperforms the standard attenuation-free model and other models of the literature. Because of model linearity, robust estimation methods can be implemented. When matched filtering is employed for single echo detection, the model that we propose yields precise estimation of the attenuation coefficient and of the sound velocity. A thickness estimation problem is also addressed through spike deconvolution, for which the proposed model also achieves accurate results.

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Spectral Shifts of Ultrasonic Propagation through Media with Nonlinear Dispersive Attenuation

Cited by 33 publications

References 3 publications

Two-layer heterogeneous breast phantom for photoacoustic imaging

Two-layer heterogeneous breast phantom for photoacoustic imaging

Conventional, Bayesian, and Modified Prony's methods for characterizing fast and slow waves in equine cancellous bone

A linear model approach for ultrasonic inverse problems with attenuation and dispersion

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