Supersonic shear imaging

[RemiDelaunay]

Supersonic shear imaging

[mlp6]

@RemiDelaunay we have used these tools for that purpose before (example: https://doi.org/10.1109/TUFFC.2014.006594); but the excitation has to be manually created using one of two approaches:

1. You can do multiple Field II simulations, one for each focal depth, and superpose those intensity fields to create a single intensity field to create the point loads. This approach neglects the timing offset between the start/finish of each sequential excitation at discrete focal depths.
2. You can run multiple FEM simulations for each single-focus excitation, which can take into account the different start/end times of the impulsive excitation, and then superpose the FEM outputs. We've used this approach in the past to evaluate the effects of the timing of the excitations (shallow -> deep foci, vs. deep -> shallow foci).

Since we decouple the acoustic simulation from the resultant tissue dynamics, you can choose what assumptions are best for your problem.

I hope this helps!

[RemiDelaunay]

@mlp6 Thank you for your detailed answer. It does help a lot !

I suppose the second solution is preferable to account for the time offset for each push. When you say 'superpose the FEM outputs', do you mean I would just need to sum the resulting displacement data for each single-focus excitation by considering the time difference between each push (in order to obtain the 'cone' shape) ? Would it requires any normalisation/pre-processing step prior the sum operation in that case ?

Remi

[mlp6]

@RemiDelaunay yep - just doing a temporally-aligned summation should work since this is all simulated as a linear system. W/r to normalization, you can take that into account w/ how you scale the Isppa for each excitation if you have experimental data to set this magnitude, or let Field II take into account the attenuation effects for each case.

[RemiDelaunay]

Great I will try that then. Thank you !