Abstract: In order to meet the non-contact characterization application requirements of the elastic properties for viscoelastic materials, a kind of acoustic radiation force elasticity imaging technology based on maximum likelihood cross-correlation time delay estimator is proposed. To solve the drawback of the resolution declining in low SNR environment of the traditional acoustic radiation force elasticity imaging method based on normalized covariance time delay estimator, this new technology uses acoustic radiation force as the driving force source to non-contactly act on the tested viscoelastic material and deform it. And the ultrasonic echo signals are processed by maximum likelihood cross-correlation time delay estimator to detect the multi-resolution deformation of the tested material. Then the spatial distribution of the relative elastic modulus value is determined to achieve the non-contact characterization purpose of the elastic properties of viscoelastic material. Simulation and experimental results indicate that the new technology provides a higher elasticity imaging resolution, especially in low SNR environment, compared with conventional acoustic radiation force elasticity imaging technology. Meanwhile, the experimental radiation force response curve of the adipose tissue is completely consistent with the Voigt viscoelastic mechanical model of biological tissues, thus proving the feasibility and effectiveness of the proposed method.

Key words: Acoustic radiation force, Elasticity imaging, Maximum likelihood cross-correlation, Time delay estimator, Voigt viscoelastic model