Empirical Optimization Of Frequency Parameters In Chirp Inversion Imaging

Contrast ultrasound imaging has become a significant imaging technique for the last ten years. Physiological and pathological information are accessible thanks to microbubble injection and nonlinearity detection. To improve resolution and penetration, frequency modulated signals called chirps combined with compression filter have been utilized by radar technology. Recent studies applied the use of chirps in harmonic imaging. And since the setup parameters of the chirp are important to enhance the microbubble nonlinearities and thus the contrast; yet their full potential is not tapped. The present study aimed to empirically optimize the harmonic energy backscattered by microbubbles through a polynomial frequency modulation law of order three. Two imaging techniques were considered: harmonic chirp imaging and chirp inversion imaging. In simulation, the frequency parameters of chirps were sought for microbubbles of different sizes (1 μm and 2.5 μm). It was beneficial to increase the order of the polynomial chirp to improve the contrast. Chirp Inversion Imaging was preferable over harmonic chirp imaging using a polynomial chirp for contrast enhancement. Moreover, optimal frequency parameters were selected manually. Optimization of polynomial chirps was empirically capable of enhancing the contrast in images however, this study is paramountly conceived by an automatic technique.