碱金属热消融特性的超声图像纹理刻画

Characterization of ultrasonic image texture for thermal ablation of alkali metal

目的碱金属热消融方法为肿瘤微创治疗提供了一种有效手段,该疗法结合了热疗与化疗的双重优势,具有显著的临床实用价值,但在热疗过程中无创监测热凝固区,并在热消融后判别热凝固区进行疗效评估是此消融手术的一个关键。本文拟采用超声图像对热疗进行评估,并选取出变化较大的纹理特征参数作为疗效评估手段。方法首先采集碱金属消融后猪肉组织的B超图像与正常组织的B超图像,利用图像纹理特征分析方法,评估灰度直方图、灰度共生矩阵等19个参数,统计20例实验结果,获得消融后变化率较大的参数,作为组织是否热凝固的判断依据。结果统计数据表明,碱金属热消融前后图像纹理特征变化较大的有灰度直方图中的灰度均值、灰度标准差以及灰度共生矩阵中0°和45°的对比度等4个参数。超声图像纹理特征可间接反映碱金属热消融的效果,并可作为热凝固区的判别依据。当灰度值增大50%及以上、灰度标准差增加100%及以上、灰度共生矩阵中对比度增加30%及以上时,可判定此时组织为凝固组织。结论本文为碱金属热消融方法的疗效评估及实时监测提供了一种有效手段,可为该疗法的快速实用化提供参考。

Objective Thermal therapy by alkali metal provides an effective method for minimally invasive cancer treatment. In particular,with combined merits from both hyperthermia and chemotherapy,such method has a strong clinical practical value. However,it is a serious problem to monitor the thermal coagulation zone and evaluate the therapeutic effect after thermal ablation. In this work,certain image texture parameters of ultrasonic images with lager change are took out for therapeutic effect evaluation. Methods In the ultrasonic images of the normal pork tissues as well as those after the alkali metal ablation,19 parameters,such as gray level histogram, gray level co-occurrence matrix, were analyzed with the method of image texture feature.Statistical results of 20 cases and parameters of the change rate were obtained. These parameters might be used as the basis to judge the tissue coagulation. Results Statistical data showed that the texture features： the mean of gray value and standard deviation in the gray histogram,the contrast of 0° and 45° in the gray level co-occurrencematrix,had a large variation after hyperthermia. Ultrasound image texture features could indirectly reflect the thermal ablation effect of alkali metal and be used as a criterion of thermal coagulation zone. When the gray value increased 50% and above,standard deviation increased 100% and above,the contrast in the gray level co-occurrence matrix increased 30% and above,the tissue could be judged as coagulation. Conclusions This paper provides an effective method for the therapeutic effect evaluation and real-time monitoring of the tumor ablation therapy by alkali metal.