Displacement Vector Field Imaging

Motivation: Conventional techniques to encode tissue displacements induced by transcranial ultrasound only capture the magnitudes. To accurately measure the displacement, the encoding gradient must be aligned with the sonication direction. Goal(s): Develop a methodology to encode the displacements as vector field. Approach: Variable encoding gradient directions were incorporated in the scan. As a proof of concept, experiments were performed in phantom and ultrasound induced displacements fields were measured using 2D circular encoding gradients. Results: The measured displacement vector field revealed converging vectors towards the focal point and diverging vectors away from the focal point. Impact: Displacement Vector Field Imaging enables the visualization of displacements induced by transcranial ultrasound by quantifying both magnitude and angle. Improved measurements of the detailed interactions of pressure waves and medium can aid precise targeting in neuromodulation studies.