Experimental Observation of Speckle Motion Artifact with Rotation

Abstract

Ultrasound speckles may move in a way that bears no simple relationship to the motion of the corresponding tissue. In some instances, the speckle motion does not replicate the underlying tissue motion and has a strong artifactual component. Kallel et al.¹ proposed an image formation model to explain the motion artifact under tissue rotation. We are now validating this model by imaging a rotating phantom with a linear array. For a rotating tissue, the model predicts an apparent movement composed of the expected rotation plus a strong horizontal translation. The model explains this translation by the non-linear phase characteristics which originate from the curvature of the system point spread function (PSF). In the far field, the translation artifact is proportional to the scan depth and the rotation angle. Using a correlation method to compute the displacement field, we can determine the amplitude of the motion artifact. This paper reports on an experimental validation of the motion artefact model predictions.