Improving contrast resolution in ultrasound holographic B-imaging: comparison between simulation and experiment

In ultrasound holographic B-imaging data are collected coherently over a synthetic aperture using a wide insonifying beam. The method under study uses monostatic approach in data acquisition which reduces significantly the amount of data and makes it feasible for real-time applications. The monostatic approach reduces, however, the dynamical range and resolution compared to a multistatic scheme. Also the numerical image focussing of the present method introduces some calculation noise typical to methods of this kind. The aim of this work was to improve contrast resolution by beamform optimization. A tissue model with a random distribution of point-scatterers was applied in simulation. The results from simulation were then verified by experiments, The simulated phantom consisted of similar internal targets as the real tissue-equivalent phantom used in experiments. Reducing the beam to the width determined by the Nyquist sampling rate improved the dynamical range more than 20 dB. The -6 dB spatial resolution was about 1 mm in a large depth range and cysts as small as 2 mm by diameter could be resolved