Tsui Po-Hsiang, Wang Chiao-Yin, Zhou Zhuhuang, Wan Yung-Liang
Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
Medical Imaging Research Center, Institute for Radiological Research, Chang Gung University and Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.
PLoS One. 2016 Sep 7;11(9):e0162488. doi: 10.1371/journal.pone.0162488. eCollection 2016.
Radiofrequency ablation (RFA) is a minimally invasive method for treating tumors. Shear wave elastography (SWE) has been widely applied in evaluating tissue stiffness and final ablation size after RFA. However, the usefulness of periablation SWE imaging in assessing RFA remains unclear. Therefore, this study investigated the correlation between periablation SWE imaging and final ablation size. An in vitro porcine liver model was used for experimental validation (n = 36). During RFA with a power of 50 W, SWE images were collected using a clinical ultrasound system. To evaluate the effects of tissue temperature and gas bubbles during RFA, changes in the ablation temperature were recorded, and image echo patterns were measured using B-mode and ultrasound statistical parametric images. After RFA, the gross pathology of each tissue sample was compared with the region of change in the corresponding periablation SWE image. The experimental results showed that the tissue temperature at the ablation site varied between 70°C and 100°C. Hyperechoic regions and changes were observed in the echo amplitude distribution induced by gas bubbles. Under this condition, the confounding effects (including the temperature increase, tissue stiffness increase, and presence of gas bubbles) resulted in artifacts in the periablation SWE images, and the corresponding region correlated with the estimated final ablation size obtained from the gross pathology (r = 0.8). The findings confirm the feasibility of using periablation SWE imaging in assessing RFA.
射频消融术（RFA）是一种治疗肿瘤的微创方法。剪切波弹性成像（SWE）已广泛应用于评估RFA术后的组织硬度和最终消融大小。然而，消融周围SWE成像在评估RFA中的作用仍不明确。因此，本研究调查了消融周围SWE成像与最终消融大小之间的相关性。使用体外猪肝模型进行实验验证（n = 36）。在功率为50 W的RFA过程中，使用临床超声系统采集SWE图像。为了评估RFA过程中组织温度和气泡的影响，记录消融温度的变化，并使用B模式和超声统计参数图像测量图像回声模式。RFA术后，将每个组织样本的大体病理与相应消融周围SWE图像中的变化区域进行比较。实验结果表明，消融部位的组织温度在70°C至100°C之间变化。观察到由气泡引起的高回声区域和回声幅度分布的变化。在此条件下，混杂效应（包括温度升高、组织硬度增加和气泡的存在）导致消融周围SWE图像出现伪像，且相应区域与从大体病理获得的估计最终消融大小相关（r = 0.8）。这些发现证实了使用消融周围SWE成像评估RFA的可行性。
