Title :
Ultrasound coefficient of nonlinearity imaging
Author :
van Sloun, Ruud ; Demi, Libertario ; Caifeng Shan ; Mischi, Massimo
Author_Institution :
Lab. of Biomed. Diagnostics, Eindhoven Univ. of Technol., Eindhoven, Netherlands
Abstract :
Imaging the acoustical coefficient of nonlinearity, β, is of interest in several healthcare interventional applications. It is an important feature that can be used for discriminating tissues. In this paper, we propose a nonlinearity characterization method with the goal of locally estimating the coefficient of nonlinearity. The proposed method is based on a 1-D solution of the nonlinear lossy Westerfelt equation, thereby deriving a local relation between β and the pressure wave field. Based on several assumptions, a β imaging method is then presented that is based on the ratio between the harmonic and fundamental fields, thereby reducing the effect of spatial amplitude variations of the speckle pattern. By testing the method on simulated ultrasound pressure fields and an in vitro B-mode ultrasound acquisition, we show that the designed algorithm is able to estimate the coefficient of nonlinearity, and that the tissue types of interest are well discriminable. The proposed imaging method provides a new approach to β estimation, not requiring a special measurement setup or transducer, that seems particularly promising for in vivo imaging.
Keywords :
bioacoustics; biological tissues; biomedical ultrasonics; speckle; 1D solution; B-mode ultrasound acquisition; acoustical coefficient; fundamental fields; harmonic fields; nonlinear lossy Westerfelt equation; nonlinearity imaging; pressure wave field; spatial amplitude variations; speckle pattern; ultrasound coefficient; ultrasound pressure fields; Attenuation; Estimation; Harmonic analysis; Imaging; Mathematical model; Ultrasonic imaging;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
DOI :
10.1109/TUFFC.2015.007009