Characterization of biological media by means of their non-linearity

Determination of nonlinear medium parameter B/A using model assisted variable-length measurement approach

“…1). In addition to effective radius, a eff , and determination of the surface pressure amplitude, P 0 , other input parameters that included the media density, sound velocity and linear attenuation coefficient were extracted from the data published in the literature [1,5,6,13]. Subsequently, with the help of the JW model it was determined that the total length of the assembly needed was equal to 120 mm.…”

“…As already noted, the primary purpose of this work was to examine whether determination of the B/A parameter in biological media could be simplified without sacrificing the achievable uncertainty of approximately 10% [1,5], and to explore whether this uncertainty could be reduced. As described in the following this was done by using a modified FA method and combining it with a semi-empirical nonlinear propagation model.…”

“…The B/A nonlinear parameter values published in the literature were experimentally obtained using either finite amplitude or thermodynamic procedures. The principles of both methods along with their advantages and disadvantages were comprehensively discussed in [1,5]. The thermodynamic (TD) procedure requires either the knowledge of the sound velocity variation with pressure or temperature or derivatives of isothermal compressibility and isobaric thermal expansion, which in general are not easy to determine experimentally.…”

Noninvasive Estimation of Temperature Elevations in Biological Tissues Using Acoustic Nonlinearity Parameter Imaging

“…A thermodynamic method (Coppens et al 1965;Zhu et al 1983) and a finite-amplitude method (Gong et al 1989;Law et al 1985) are most commonly used to measure this parameter for liquid and liquid-like media. It has been reported that, compared with the linear ultrasonic parameters, the acoustic nonlinearity parameter B/A can provide more information on the state of the tissues and may become a novel parameter for biological tissue characterization (Bjørnø 1986;Gong et al 1993;Law et al 1985;Muir and Carstensen 1980;Sehgal et al 1986;Yoshizumi et al 1987). To explore the potential applications of this parameter in ultrasound imaging, several imaging techniques have been proposed (Cain 1986;Gong et al 2004;Ichida et al 1983Ichida et al , 1984Nakagawa et al 1986;Zhang et al 1996Zhang et al , 1999.…”

Acoustic nonlinearity parameter tomography for biological tissues via parametric array from a circular piston source—Theoretical analysis and computer simulations

“…For enhancement of the discrimination and evaluation of healthy and diseased tissues, much attention has been directed to the acoustic nonlinearity parameter B/A in the field of ultrasonic biomedicine. 1,2 The acoustic nonlinearity parameter B/A is an important parameter in nonlinear acoustics, which is defined as the ratio of the coefficients of the quadratic term to the linear term in the Taylor expansion of the state equation: B/A ϭ2 0 c 0 (‫ץ‬c/‫ץ‬p) o,s , 3 where 0 and c 0 are the density and velocity of the medium, p is the static pressure, and s is the entropy. Many reports have indicated that compared with linear ultrasonic parameters the acoustic nonlinearity parameter B/A could provide more information on the state of the tissues.…”