Ultrasound pulse reflection mode measurement of nonlinearity parameter B/A and attenuation coefficient

Abstract

A new method for obtaining depth distribution of the nonlinearity parameter B/A and the frequency-dependent attenuation coefficient is outlined. In this method, the higher frequency probe pulse wave, superposed coaxially on the lower frequency pump pulse wave, is modulated nonlinearly due to their propagation, and is received as an echo signal. The relationship between these acoustic parameters and the modulation characteristics of the probe pulse wave is derived by the division of the spectra of modulated echo signals with each other. The possibility of canceling out of error factors, such as the frequency-dependent acoustic reflection coefficient of random scattering medium, in the above division process is discussed. A preliminary evaluation of this method is made by using an experimental system. B/A values are obtained for various kinds of sponge test targets immersed in water, n-propyl alcohol, isopropyl alcohol, ethylene glycol, or diethylene glycol; and for agar graphite phantom.

Post-processing enhancement of reverberation-noise suppression in dual-frequency SURF imaging

“…A variant of the time-delay post-processing adjustment analyzed in the present article is also considered. Furthermore, dual-frequency pulse insonification has been employed for imaging the nonlinearity parameter of different media [12][13][14][15][16][17].…”

Nonlinear propagation acoustics of dual-frequency wide-band excitation pulses in a focused ultrasound system

“…The increased or decreased sound velocity causes a time delay, and the linearly variable sound velocity a compression/expansion of the imaging pulse relative to the case when no manipulation pulse is present. This phenomenon is described and demonstrated by Fukukita et al, 10,11,13 and may be used for B/A estimation.…”

“…Fukukita et al 13 used a five-element annular array to generate a 2.5 MHz pulse, and a coaxial concentric external ring element for a 0.3 MHz pulse in order to transmit these pulses simultaneously for B/A estimation. The same solution was used by Måsøy et al 3 to generate a dual-frequency band transmit pulse of 0.9 MHz and 7.5 MHz for ultrasound contrast detection at 7.5 MHz.…”

“…A series of papers where dual-frequency pulse complexes were used to estimate or image the nonlinear parameter B/A in tissues and liquids have been published. [6][7][8][9][10][11][12][13] Ultrasound contrast agents are particularly sensitive to the manipulation pulse, and changes in their scattering properties may then be probed by the imaging pulse to form a high-frequency contrast agent detection technique. These effects have been demonstrated by several groups, including the authors of this article, through theory, simulations and laboratory measurements.…”

Preliminary investigation of nonlinear dual frequency mixing technique for the estimation of the nonlinear parameter B / A

“…The nonlinear parameter also describes the dependence of ultrasonic velocity on applied pressure. To estimate B/A Ravimeher [1], Ichida [2], Deahoon [3], Sehgal [4] and Fukukita [5] measured the variation in speed of sound as a function of the variations of the ambient pressure generated using a hydraulic pump. Deahoon [3] used this technique to generate B/A parametric images.…”