高强度聚焦超声治疗子宫肌瘤中水囊耦合的影响评估*

水囊作为一种特殊的辅助器件在高强度聚焦超声治疗子宫肌瘤的过程中发挥着重要作用，但它同时也会让声通道变得更加复杂，对超声治疗效率和超声引导影像均造成负面影响。基于实际临床场景，利用k-Wave声学仿真软件建立高强度聚焦超声辐照靶组织及其超声引导过程的仿真模型，在有无水囊两个场景下，对治疗效率和监控影像质量进行定量评估。结果表明，加入水囊后，声波的聚焦性变差，焦域处的最高温度降低；通过分析超声图像的分辨率、对比度、对比噪声以及背景信噪比，发现加入水囊后超声图像的质量降低。建立的数值仿真模型能够初步评估水囊对治疗效率和监控影像质量的影响，可作为一种评估体系用于优化水囊参数，如水囊材料、厚度、形状、内部溶液成分等，为下一步实验探索对治疗效率和影像质量影响最小的水囊耦合方式提供评估手段。

Evaluation of the effect of water bag on high intensity focused ultrasound in the treatment of uterine fibroids

As a special coupling method, water bag plays an important role in the treatment of uterine fibroids by high-intensity focused ultrasound. However, it also makes the acoustic passage more complicated and negatively affects the efficiency of ultrasound treatment and the quality of ultrasound-guiding image. Based on the realistic clinical settings, k-Wave acoustic simulation software was used to establish a model of the target tissue being irradiated by high-intensity focused ultrasound and its ultrasonic guidance process. The therapeutic efficiency and guiding image quality were quantitatively evaluated in two scenarios with or without water bag. These results show that the acoustic focusing became worse and the maximum temperature at the focal region decreased after the water bag was added. By analyzing the resolution, contrast, contrast noise and background signal-to-noise ratio of ultrasonic image, it is found that the quality of ultrasonic image decreased when there was a water bag within the acoustic passage. Numerical simulation model established in this paper can preliminarily assess the influence of water bag on the treatment efficiency and on the monitoring image quality. The proposed method can be used as a kind of evaluation platform for optimizing the water bag parameters, such as its material, thickness, shape, and its internal solution composition. This study also laid the foundation for searching for new water bag with experiment methods in the future.