Acoustic Radiation Force Impulse Imaging Using Displacements of Lateral Dimension

Acoustic radiation force (ARF) induced elasticity imaging is usually used to obtain the elastic properties of media by detecting the induced displacement at the focal point. However, the ARF induced displacement response actually appears not only at the focal point, but also in lateral dimension at the focal depth. The relationship between the stiffness of media and the axial-directional displacements in lateral dimension at the focal depth has been analyzed through theoretical derivation, simulation and experimental verification. The results demonstrate that the maximum displacement in lateral dimension is inversely proportional to the lateral distance from the currently estimated point to the focal point. Therefore, the maximum displacement in lateral dimension at the focal depth is capable of estimating the elastic properties of the media. Based on this conclusion, an ARF impulse imaging method using displacements of lateral dimension is proposed. The induced displacements at the focal point as well as in the lateral dimension at the focal depth are detected under only the focal point excited. In this way, the proposed imaging method is expected to broaden the ARF impulse imaging region from the focal point to a larger region in the lateral dimension while reducing patient acoustic exposure and transducer heating.