Ultrasound contrast agents modeling using an extended Volterra model

Fatima Sbeity (1) , Jean-Marc Girault (1) , Sébastien Ménigot , Jamal Charara (2)

1 iBraiN - Imaging, Brain & Neuropsychiatry
2 LU / ULB - الجامعة اللبنانية [بيروت] = Lebanese University [Beirut] = Université libanaise [Beyrouth]

Harmonic imaging has historically occurred with the introduction of ultrasound contrast agents such as microbubbles. These agents, due to their nonlinear behavior, have provided a great increase in the contrast of ultrasound images. Although this modality has revolutionized the clinical practice, it still suffers from the presence of harmonics in the echo of the tissue that reduce its efficiency. One way to overcome this problem was to turn to the sub-harmonic imaging based on the reception of sub-harmonics generated by microbubbles at high pressure levels. Modeling of the signals backscattered by microbubbles was performed with nonlinear models such as Volterra series. These models have exhibited high efficiency in modeling harmonics. However, they are inadequate to model sub- and ultra-harmonics. In this paper, we propose an extension of the Volterra series in order to model these sub- and ultra-harmonics. Results showed that signals backscattered by the medium infused with microbubbles can be accurately represented by the derived model. The gain achieved with our method was 2.3 dB compared to the standard Volterra modeling. In the frequency domain, the spectrum of the simulated signal has described perfectly that of the microbubble.

Mots clés: Identification; microbubbles; sub-harmonics; Volterra model

Domaines: Acoustique [physics.class-ph]

Fatima Sbeity, Jean-Marc Girault, Sébastien Ménigot, Jamal Charara. Ultrasound contrast agents modeling using an extended Volterra model. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810770⟩