A model-based synthetic aperture image reconstruction technique for high-frequency ultrasound

A synthetic aperture focusing approach is presented, which is based on the cross-correlation of the measured data with the simulated depth-dependent response to a point scatterer of the imaging system. The method has been evaluated by measurements using a 20 MHz ultrasound system with a fixed-focus single-element transducer. The simulation of the system´s response is carried out with Field II. Measurements of a wire phantom show a depth-independent lateral and axial resolution below the focal point, even for large imaging depths and an increase of signal-to-noise ratio (SNR). These results are confirmed with small animal imaging experiments. The method is applicable to the near- and the far-field of the transducer, given that it is possible to simulate the system response.