HIFU ablation monitoring with weighted ultrasound entropy imaging

Although B-mode imaging has been widely used in ultrasound-guided high-intensity focused ultrasound (HIFU) treatment, challenges remain in improving its quality and sensitivity for monitoring the thermal dose. Recently, quantitative ultrasound (QUS) imaging has been recognized with the potential to better sense the changes in the microstructure of ablated tissues. This study proposed to use a QUS method called weighted ultrasound entropy (WUE) imaging to monitor the HIFU ablation. Performance of the proposed WUE imaging in the monitoring of HIFU treatment was compared with the corresponding B-mode images in terms of their contrast-to-noise ratios (CNRs) between the focal region and the background. The performance of the proposed WUE method was evaluated through experiments with ex-vivo sample tissue and live rabbit liver. Results show that the WUE images had higher image quality in indicating lesion formation, with a 39.2% to 53.4% improvement in the CNR at different stages compared with the in-situ B-mode images. WUE imaging is more sensitive and accurate than B-mode imaging in monitoring HIFU therapy.