Study on Preoperative HIFU Focus prediction Using Harmonic Motion Imaging

Precise preoperative localization of the treatment focus remains a significant challenge in high intensity focused ultrasound (HIFU) technology. Recently, ultrasound Harmonic Motion Imaging (HMI) has been applied to localize and monitor HIFU treatments. In this study, we investigated the effects of amplitude modulation frequency and acoustic power in HMI on localizing the focus of HIFU. Experiments were performed using ex-vivo pork tenderloin and beef liver tissues, with modulation frequencies ranging from 25 Hz to 100 Hz and acoustic powers from 0.7 W to 28 W. The HMI-based localization method was compared with post-treatment ultrasound B-mode images, and localization errors were quantitatively assessed. The localization errors of the method in ex-vivo pork tenderloin and beef liver tissues were 0.7 ± 0.2 mm and 0.5 ± 0.3 mm, respectively, when the acoustic power was 15 W. Using a focal localization error of less than 1 mm as a criterion for determining the effectiveness of the HMI-based localization method, the localization rates of the method were higher than 90% for ex-vivo pork tenderloin with acoustic power higher than 15 W, and reached 100% for beef liver when the acoustic power was higher than 7 W.