Image reconstruction from shear wave modulated ultrasound echo data

Conventional ultrasound imaging uses mechanically focused transducers and/or delay-and-sum beamforming to focus transmit and receive beams and provide lateral resolution. Lateral resolution is determined by aperture size and wavelength. A sound speed of 1540 m/s is typically assumed; sound speed variations may degrade the focus. We present a novel method in which lateral resolution of the target is obtained by using traveling shear waves to encode the lateral position of targets in the phase of the received echo. This method separates the lateral resolution of the imaging system from the properties of the ultrasound aperture. We demonstrate image formation with an unfocused transducer in phantoms of uniform shear modulus.