摘　要：为了解决高强度聚焦超声（HIFU）治疗中的监测问题，在无需引入其他监测源的情况下，通过研究HIFU回波基波与二次谐波的多尺度模糊熵（MFE），提出了一种生物组织变性辨析新方法。HIFU回波信号通过谱减法去噪后，利用信息散度优化的变分模态分解（KLD-VMD）提取其基波与二次谐波分量，然后结合基波与二次谐波的MFE对组织进行变性识别，并使用等错误概率（EER）评价了该方法的有效性。最后，研究还比较了KLD-VMD与VMD、经验模态分解（EMD）和固有时间尺度分解（ITD）等其他分解方法，结合MFE分析了其辨析变性组织的能力。试验结果表明：基于KLD-VMD和MFE的组织变性识别其EER达到5.1%，相较于其他方法表现出了更好的识别效果；结合基波和二次谐波的识别结果比使用单一特征参数更好。该研究为HIFU治疗提供了一种新的监测方法，具有潜在的实际应用价值。

关键词：HIFU回波信号；优化变分模态分解；多尺度模糊熵；生物组织损伤识别；肿瘤治疗方式

中图分类号：TN911.7                       文献标志码：ADOI：10.3969/j.issn.1007-7146.2024.01.005

Abstract: To address the monitoring problem in high-intensity focused ultrasound (HIFU) therapy, a new method is proposed for identification of tissue damage without the need for additional monitoring sources. The method involves studying the multiscale fuzzy entropy (MFE) of the fundamental and second harmonic of the HIFU echo. The HIFU echo signal is denoised using spectral subtraction, and then the fundamental and second harmonic components of the signal are extracted using the kullback-leibler divergence-optimized variational mode decomposition (KLD-VMD) method. Finally, the MFE combining the fundamental and second harmonic is used to identify tissue damage. The validity of the method is verified using the equal error rate (EER), where a lower EER indicates better recognition. The study also compares the KLD-VMD method with other decomposition methods such as VMD, EMD, and ITD, in combination with MFE for tissue damage identification. The experimental results demonstrate that the tissue damage identification based on KLD-VMD and MFE achieves an EER of 5.1%, which is better compared to the other methods. Furthermore, the results also show that combining the fundamental and second harmonics improves the identification performance compared to using either echo alone. This study provides a new monitoring method for HIFU therapy with potential practical applications.

Key words: HIFU echo; optimized variational mode decomposition; multiscale fuzzy entropy; identification of tissue damage; tumor treatment methods

（Acta Laser Biology Sinica, 2024, 33(1): 040-047）