Optimisation des paramètres fréquentiels du signal d'émission appliquée à l'imagerie de contraste ultrasonore du second harmonique

Many ultrasound contrast-imaging techniques use the nonlinear behavior of contrast agents to enhance the contrast of medical images. They are based on the generation of harmonic frequencies when microbubbles are insonified by ultrasound waves. The frequential parameters of the transmitted ultrasound signal maximize the harmonic power of microbubbles. We propose an adaptive method, which seeks automatically the optimal pulse parameters. These parameters allow us to maximise an energetic cost-function. The transmitted signal is composed of two different half-sines truncated, instead of a sinus wave composed of two identical half-sines truncated. With the used simulation model, the method can gives us a gain of 1,3 dB compared with the non-optimized system. Such results are interesting and encourage us to continue in this way.