Difference-Frequency-Based Ultrasonic Contrast Imaging of Material Elasticities

The nonlinear interaction of two waves causes a signal at their difference frequency. Difference-frequency ultrasound (dfUS) is highly dependent on material stiffness, making it a superior alternative to conventional linear ultrasound when it comes to elastographic contrast imaging. We have constructed a 64-element ring array for dfUS imaging based on a 32×32 2D matrix array and conducted experiments on phantoms with various material stiffnesses. The results were quantitatively analyzed and successfully used to implement an elastographic contrast image.