Wang Chiao-Yin, Zhou Zhuhuang, Chang Yu-Hsuan, Ho Ming-Chih, Lu Chiu-Min, Wu Chih-Horng, Tsui Po-Hsiang
Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China.
Front Oncol. 2022 Jul 22;12:894246. doi: 10.3389/fonc.2022.894246. eCollection 2022.
Radiofrequency ablation (RFA) is an alternative treatment for early-stage hepatocellular carcinoma (HCC). The production of gas bubbles by RFA indicates threshold temperature of tissue necrosis and results in changes in backscattered energy (CBE) when ultrasound monitors RFA. In this study, ultrasound single-phase CBE imaging was used as a means of monitoring RFA of the liver tumor by analyzing the backscattering of ultrasound from gas bubbles in the liver. A total of 19 HCC patients were enrolled in the study. An ultrasound system was used during RFA to monitor the ablation process and acquire raw image data consisting of backscattered signals for single-phase CBE imaging. On the basis of single-phase CBE imaging, the area corresponding to the range of gas bubbles was compared with the tumor sizes and ablation zones estimated from computed tomography. During RFA, ultrasound single-phase CBE imaging enabled improved visualization of gas bubbles. Measured gas bubble areas by CBE were related to tumor size (the Spearman correlation coefficient = 0.86; < 0.05); less dependent on the ablation zone. Approximately 95% of the data fell within the limits of agreement in Bland-Altman plots, and 58% of the data fell within the 95% CI. This study suggests that single-phase CBE imaging provides information about liver tumor size because of the abundant vessels in liver tumors that promote the generation of gas bubbles, which serve as natural contrast agents in RFAs to enhance ultrasound backscattering. Ultrasound single-phase CBE imaging may allow clinicians to determine if the required minimum RFA efficacy level is reached by assessing gas bubbles in the liver tumors.
射频消融（RFA）是早期肝细胞癌（HCC）的一种替代治疗方法。RFA产生的气泡表明组织坏死的阈值温度，并且在超声监测RFA时会导致背向散射能量（CBE）发生变化。在本研究中，超声单相CBE成像通过分析肝脏中气泡的超声背向散射，被用作监测肝肿瘤RFA的一种手段。共有19例HCC患者纳入本研究。在RFA期间使用超声系统监测消融过程，并获取由背向散射信号组成的原始图像数据用于单相CBE成像。基于单相CBE成像，将与气泡范围对应的区域与根据计算机断层扫描估计的肿瘤大小和消融区进行比较。在RFA期间，超声单相CBE成像能够更好地显示气泡。通过CBE测量的气泡面积与肿瘤大小相关（Spearman相关系数 = 0.86；<0.05）；对消融区的依赖性较小。在Bland-Altman图中，约95%的数据落在一致性界限内，58%的数据落在95%CI内。本研究表明，由于肝肿瘤中丰富的血管促进了气泡的产生，单相CBE成像可提供有关肝肿瘤大小的信息，这些气泡在RFA中作为天然对比剂增强超声背向散射。超声单相CBE成像可能使临床医生通过评估肝肿瘤中的气泡来确定是否达到所需的最低RFA疗效水平。
