The State Key Laboratory of Ultrasound Engineering in Medicine, College of Biomedical Engineering, Chongqing Medical University, Chongqing, China.
The School of Microelectronics, Tianjin University, Tianjin, China.
Med Phys. 2024 Nov;51(11):8247-8259. doi: 10.1002/mp.17340. Epub 2024 Aug 2.
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.
Based on ex-vivo and in-vivo experiments, WUE images reflecting tissue changes during HIFU treatment under different acoustic power levels (174-308 W) were reconstructed with a newly established imaging framework. The 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.
It was found that HIFU irradiation with higher power generated larger WUE values in the focal region, and the bright spots grew in size as the acoustic sonication proceeded. Compared with the in-situ B-mode images, the WUE images had higher image quality in indicating lesion formation, with a 39.2%-53.4% improvement in the CNR at different stages. Meanwhile, a correlation (R = 0.84) between the damage area estimated in WUE images and that measured from the dissected ex-vivo tissue samples was found.
WUE imaging is more sensitive and accurate than B-mode imaging in monitoring HIFU therapy. These findings suggest that WUE imaging could be a promising technique for assisting ultrasound-guided HIFU ablation.
尽管 B 模式成像已广泛应用于超声引导高强度聚焦超声（HIFU）治疗，但在提高其质量和敏感性以监测热剂量方面仍存在挑战。最近，定量超声（QUS）成像已被认为具有更好地感知消融组织微结构变化的潜力。
本研究提出使用一种称为加权超声熵（WUE）成像的 QUS 方法来监测 HIFU 消融。
基于离体和体内实验，使用新建立的成像框架重建了反映不同声功率水平（174-308 W）下 HIFU 治疗过程中组织变化的 WUE 图像。在所提出的 WUE 成像在监测 HIFU 治疗中的性能方面，与相应的 B 模式图像相比，其焦点区域与背景之间的对比噪声比（CNR）。
结果发现，功率较高的 HIFU 照射在焦点区域产生较大的 WUE 值，并且随着声刺激的进行，亮点的尺寸增大。与原位 B 模式图像相比，WUE 图像在指示病变形成方面具有更高的图像质量，在不同阶段的 CNR 提高了 39.2%-53.4%。同时，在 WUE 图像估计的损伤面积与从离体组织样本测量的损伤面积之间发现了相关性（R=0.84）。
WUE 成像在监测 HIFU 治疗方面比 B 模式成像更敏感、更准确。这些发现表明，WUE 成像可能是一种有前途的技术，可用于辅助超声引导的 HIFU 消融。
