Fast simulation of nonlinear radio frequency ultrasound images in inhomogeneous nonlinear media: CREANUIS

International audienceThe simulation of ultrasound image is usually based on two main strategies: either a linear convolution or the use of an acoustics model. However, only the linear propagation of the pressure wave is considered. CREANUIS is a recent simulation tool (freely available on the Internet: http://www.creatis.insa-lyon.fr/site/en/CREANUIS) which implements the nonlinear propagation of the wave to create realistic ultrasound images [Varray et al., IEEE International Ultrasonics Symposium 201] and opens new simulations perspectives based on nonlinear propagation: amplitude modulation, pulse inversion, second harmonic inversion... The nonlinear propagation in CREANUIS is simulated using a generalization of the angular spectrum method (GASM). This approach is implemented on a graphic processing unit (GPU) for a fast computation. Moreover, in GASM simulation, the possible inhomogeneity of the nonlinear parameter can be considered. It directly impacts the increase of the harmonics during propagation and consequently the resulting RF image. These resulting images perfectly translate the nonlinear parameter change in the medium. Finally, the total computation time for CREANUIS (fundamental and second-harmonic image) compared to FieldII (fundamental image only) is reduced by a factor comprised between 2 and 4 according to the geometric considerations