Twinkling artifact of Doppler imaging for cavitation detection during high-intensity focused ultrasound therapy: Sensitivity and resolution

Abstract

The mechanism of the twinkling artifact (TA) during Doppler imaging of kidney stones is well-known and is hypothesized to stem from the irregular scattering of Doppler ensemble pulses from fluctuating microbubbles trapped in crevices of the kidney stone. We have previously demonstrated that the TA can be used to detect and image microbubbles in soft tissue during pulsed HIFU treatment. In this work, the characteristics of the method—the sensitivity to small bubbles and the spatial resolution—were investigated experimentally and compared to other passive and active cavitation imaging methods such as pulse inversion. An approach was proposed for quantification of the cavitation images provided by the method, and the resulting metric was compared to the inertial cavitation dose. The experiments were performed using pulsed 1-MHz HIFU exposures of transparent gel phantoms, ex vivo tissue and in vivo mouse model of pancreatic cancer. [Work supported by RFBR and NIH (EB007643, 1K01EB015745, and R01CA154451).]